A class of oscillator of the El Ni?o-Southern
oscillation model is considered. Using Mawhin's continuation
theorem, a result on the existence of periodic solutions for ENSO
model is obtained.

A reduces equation of the Kelvin wave is considered. By
using the homotopic mapping solving method, the approximate solution
is obtained. The homptopic mapping method is an analytic method,
the obtained solution can analyse operations sequentially.

The dynamical behaviour of the generalized Korteweg-de
Vries (KdV) equation under a periodic perturbation is investigated
numerically. The bifurcation and chaos in the system are observed by
applying bifurcation diagrams, phase portraits and Poincaré maps.
To characterise the chaotic behaviour of this system, the spectra of
the Lyapunov exponent and Lyapunov dimension of the attractor are also
employed.

We derive the non-dimensional coupling equation of two
exciters, including inertia coupling, stiffness coupling and load
coupling. The concept of general dynamic symmetry is proposed to
physically explain the synchronisation of the two exciters, which
stems from the load coupling that produces the torque of general
dynamic symmetry to force the phase difference between the two
exciters close to the angle of general dynamic symmetry. The
condition of implementing synchronisation is that the torque of
general dynamic symmetry is greater than the asymmetric torque of
the two motors. A general Lyapunov function is constructed to derive
the stability condition of synchronisation that the non-dimensional
inertia coupling matrix is positive definite and all its elements are
positive. Numeric results show that the structure of the vibrating
system can guarantee the stability of synchronisation of the two
exciters, and that the greater the distances between the
installation positions of the two exciters and the mass centre of
the vibrating system are, the stronger the ability of general
dynamic symmetry is.

This paper constructs an almost-Poisson structure for the
non-self-adjoint dynamical systems, which can be decomposed into a
sum of a Poisson bracket and the other almost-Poisson bracket. The
necessary and sufficient condition for the decomposition of the
almost-Poisson bracket to be two Poisson ones is obtained. As an
application, the almost-Poisson structure for generalised
Chaplygin's systems is discussed in the framework of the
decomposition theory. It proves that the almost-Poisson bracket for
the systems can be decomposed into the sum of a canonical Poisson
bracket and another two noncanonical Poisson brackets in some special
cases, which is useful for integrating the equations of motion.

This paper studies the symmetry of Lagrangians of
nonholonomic systems of non-Chetaev's type. First, the definition
and the criterion of the symmetry of the system are given. Secondly,
it obtains the condition under which there exists a conserved
quantity and the form of the conserved quantity. Finally, an example
is shown to illustrate the application of the result.

Mei symmetry and Mei conserved quantity of Appell
equations for a variable mass holonomic system are investigated.
Appell equations and differential equations of motion for a variable
mass holonomic system are established. A new expression of the total
first derivative of the function with respect of time t along the
systematic motional track curve, and the definition and the
criterion of Mei symmetry for Appell equations under the
infinitesimal transformations of groups are given. The expressions
of the structural equation and Mei conserved quantity for Mei
symmetry in Appell are obtained. An example is given to illustrate
the application of the results.

Mei symmetry and Mei conserved quantity of Nielsen
equations for a non-holonomic, non-conservative system of Chetaev's
type with variable mass are studied. The differential equations of
motion of the Nielsen equation for the system, the definition and
criterion of Mei symmetry, and the condition and the form of Mei
conserved quantity deduced directly by Mei symmetry for the system
are obtained. An example is given to illustrate the application of
the results.

Recently the (G'/G)-expansion
method was proposed to find the traveling wave solutions of
nonlinear evolution equations. This paper shows that the
(G'/G)-expansion method is a special form of the truncated
Painlevé expansion method by introducing an intermediate
expansion method. Then the generalized
(G'/G)--(G'/G) expansion method is naturally
derived from the standpoint of the nonstandard truncated
Painlevé expansion. The application of the generalized method to
the mKdV equation shows that it extends the range of exact solutions
obtained by using the (G'/G)-expansion
method.

A new approach is developed to solve the Green's function
that satisfies the Hehmholtz equation with complex refractive index.
Especially, the Green's function for the Helmholtz equation can be
expressed in terms of a one-dimensional integral, which can convert
a Helmholtz equation into a Schr?dinger equation with complex
potential. And the Schr?dinger equation can be solved by Feynman path
integral. The result is in excellent agreement with the previous
work.

Using the method developed by Gurvitz [1996 Phys. Rev. B 53 15932], we obtained the Bloch-type rate equations
describing the entire system of a periodically driving qubit monitored by a quantum point contact detector. The results
demonstrate that the isolated qubit can be kept in its initial state with a large driving frequency due to more difficult electron tunneling in qubit, and this initial state can always be measured at a small measurement-induced decoherence rate during a short time.

In this paper, the entanglement dynamics of a double
two-photon Jaynes--Cummings model with Kerr-like medium is
investigated. It is shown that initial entanglement has an
interesting subsequent time evolution, including the so-called
entanglement sudden death effect. It is also shown analytically that
the Kerr-like medium can repress entanglement sudden death and enhance
the degree of atom--atom entanglement. A more interesting fact is
that the Kerr effect is more obvious when each of the two cavities
with have the Kerr-like medium than only one of them with the Kerr-like medium.

A scheme is proposed to controll the decoherence of
three-level rf-SQUID qubit with asymmetric potential by designing an
external electric circuit for superconductive flux qubit. The
results show that it may not only raise the gate speed but also extend
decoherence time for a three-level structure.

A scheme, based on the system composed of three atoms
separately trapped in three cavities coupled by optical fibres, for
entangling two distant atoms via the adiabatic passage is proposed. It
is found that the multi-particle W entangled state can also be
generated. Moreover, the quantum information sharing can be
implemented using this system. These results may be helpful for the
implementation of quantum network and useful in quantum
cryptography. This scheme is also convenient for operating since only
the laser fields applied to the atoms need to be adjusted to
accomplish the processes.

This paper applies the minimum variance V_{1} criterion to
monitor the evolution of signal and idler modes of a composite
non-degenerate optical parametric amplification (NOPA) system. The analytics
and numerical calculation show the influence of the transition time,
the vacuum fluctuations, and the thermal noise level on the EPR
entanglement of the composite NOPA system. It finds that the
entanglement and the squeezing degrade as the minimum variance V_{1}
increases.

We propose a scheme to engineer a non-local two-qubit
phase gate between two remote quantum-dot spins. Along with
one-qubit local operations, one can in principal perform various
types of distributed quantum information processing. The scheme
employs a photon with linearly polarisation interacting one after
the other with two remote quantum-dot spins in cavities. Due to the
optical spin selection rule, the photon obtains a Faraday rotation
after the interaction process. By measuring the polarisation of the
final output photon, a non-local two-qubit phase gate between the
two remote quantum-dot spins is constituted. Our scheme may has very
important applications in the distributed quantum information
processing.

The Homotopy analysis method is applied to obtain the approximate solution of the Klein--Gordon--Schr?dinger equation. The Homotopy analysis solutions of the Klein--Gordon--Schr?dinger equation contain an auxiliary parameter which provides a convenient way to control the convergence region and rate of the series solutions. Through errors analysis and numerical simulation, we can see the approximate solution is very close to the exact solution.

The multipole moment method not only conduces to the
understanding of the deformation of the space--time, but also serves
as an effective tool to approximately solve the Einstein field
equation with. However, the usual multipole moments are recursively
determined by a sequence of symmetric and trace-free tensors, which
is inconvenient for practical resolution. In this paper, we develop
a simplified procedure to generate the series solutions to the
metric of the stationary vacuum with axisymmetry, and show its
validity. In order to understand the free parameters in the
solution, we propose to take the Schwarzschild metric as a standard
ruler, and some well- known examples are analysed and compared with
the series solutions in detail.

A logit-based discrete choice model is proposed to study
the exit choice behaviour of evacuees in rooms with internal
obstacles and multiple exits. Several factors influencing the exit
choice behaviour, including the information obtained by evacuees,
the tendency of following others, the visibility and familiarity of
exits and the physical conditions of nearby exits, are considered.
Evacuees are allowed to re-select their target exits for minimizing
the perceived disutility during evacuation process. Numerical
results from applying the model to cellular automata simulation of
evacuation are presented and the effects of some model parameters on
evacuation time are investigated.

Based on the thermodynamic potential function of Fermi gas
in a strong magnetic field, using the thermodynamics method, the
integrated analytical expressions of thermodynamic quantities of the
system at low temperatures are derived, and the effects of the
magnetic field on the statistic properties of the system are
analysed. It is shown that, as long as the temperature is not zero, the
effects of the magnetic field on the thermodynamic quantities of the
system contain both oscillatory and non-oscillatory parts. For the
non-oscillatory part, compared with the situation of Fermi gas in a
weak magnetic field, the influence of the magnetic field on the
thermodynamic quantities is not exactly the same. For the
oscillatory part, the period and amplitude of the oscillation are
all related to the magnetic field. Due to the oscillation, the chemical
potential may be greater than Ferim energy of the system, but the
oscillation does not affect the thermodynamic stability of the
system.

We have investigated in the adiabatic limit the phenomenon
of stochastic resonance in the gene transcriptional regulatory
system subjected to an additive noise, a multiplicative noise, and a
weakly periodic signal. Using the general two-state approach for the
asymmetry system, the analytic expression of signal-to-noise ratio
is obtained. The effects of the additive noise intensity α,
the multiplicative noise intensity D and the amplitude of input
periodic signal A on the signal-to-noise ratio are analysed by
numerical calculation. It is found that the existence of a maximum
in the R_{SNR}--α and R_{SNR}--D plots is the
identifying characteristic of the stochastic resonance phenomenon in
the weakened noise intensity region. The stochastic resonance
phenomena are restrained with increasing α and D, and
enhanced with increasing A.

The behaviour of the current in a two-dimensional
Büttiker--Landauer motor, which is a position-dependent
temperature-driven Brownian motor, is investigated in the presence
of entropic and energy barriers. It is found that the motion of the
Brownian particles is influenced by the shape of the channel. The
existence of an entropic barrier can cause an asymmetric current as
the flatness ratio of the shape varies. There exists an optimized
flatness ratio (nonzero) at which the current reaches its maximum
value.

This paper investigates the chaos synchronisation between
two coupled chaotic Chua's circuits. The sufficient condition presented
by linear matrix inequalities (LMIs) of global asymptotic
synchronisation is attained based on piecewise quadratic Lyapunov
functions. First, we obtain the piecewise linear differential
inclusions (pwLDIs) model of synchronisation error dynamics, then we
design a switching (piecewise-linear) feedback control law to
stabilise it based on the piecewise quadratic Laypunov functions.
Then we give some numerical simulations to demonstrate the
effectiveness of our theoretical results.

The chaotic oscillator has already been considered as a
powerful method to detect weak signals, even weak signals
accompanied with noises. However, many examples, analyses and
simulations indicate that chaotic oscillator detection system cannot
guarantee the immunity to noises (even white noise). In fact the
randomness of noises has a serious or even a destructive effect on
the detection results in many cases. To solve this problem, we
present a new detecting method based on wavelet threshold processing
that can detect the chaotic weak signal accompanied with noise. All
theoretical analyses and simulation experiments indicate that the
new method reduces the noise interferences to detection
significantly, thereby making the corresponding chaotic oscillator
that detects the weak signals accompanied with noises more stable
and reliable.

The eigenvalue space of the canonical four-dimensional
Chua's circuit which can realize every eigenvalue for
four-dimensional system is studied in this paper. First, the
analytical relations between the circuit parameters and the
eigenvalues of the system are established, and therefore all the
circuit parameters can be determined explicitly by any given set of
eigenvalues. Then, the eigenvalue space of the circuit is
investigated in two cases by the nonlinear elements used. According
to the types of the eigenvalues, some novel hyperchaotic attractors
are presented. Further, the dynamic behaviours of the circuit are
studied by the bifurcation diagrams and the Lyapunov spectra of the
eigenvalues.

A modified spatially extended Tang--Othmer Ca^{2+}
model is used to study intracellular Ca^{2+} spiral waves
numerically. It is found that, as a local stimulation, the local
agonist-binding on the cell membrane，which enhances the local
concentration of the messenger molecule inositol
1,4,5-trisphosphate(IP_{3}), can influence the dynamics of the
spiral waves. {1}) Strong enough stimuli can change the spiral wave
from a meandering to a rigidly rotating one. {2}) On the other hand,
strong enough stimuli can suppress the spiral wave from the system.
It provides the theoretical clue for controlling the spiral waves by
stimulating the cell membrane.

This paper reports a new hyperchaotic system by adding an
additional state variable into a three-dimensional chaotic dynamical
system. Some of its basic dynamical properties, such as the
hyperchaotic attractor, Lyapunov exponents, bifurcation diagram and
the hyperchaotic attractor evolving into periodic, quasi-periodic
dynamical behaviours by varying parameter k are studied. An effective
nonlinear feedback control method is used to suppress hyperchaos to
unstable equilibrium. Furthermore, a circuit is designed to realize
this new hyperchaotic system by electronic workbench (EWB).
Numerical simulations are presented to show these results.

This paper presents a new smooth memristor oscillator,
which is derived from Chua's oscillator by replacing Chua's diode
with a flux-controlled memristor and a negative conductance. Novel
parameters and initial conditions are dependent upon dynamical behaviours
such as transient chaos and stable chaos with an intermittence
period and are found in the smooth memristor oscillator. By using
dynamical analysis approaches including time series, phase portraits
and bifurcation diagrams, the dynamical behaviours of the proposed
memristor oscillator are effectively investigated in this paper.

Direct time delay feedback can make non-chaotic Chen
circuit chaotic. The chaotic Chen circuit with direct time delay
feedback possesses rich and complex dynamical behaviours. To reach a
deep and clear understanding of the dynamics of such circuits
described by delay differential equations, Hopf bifurcation in the
circuit is analysed using the Hopf bifurcation theory and the
central manifold theorem in this paper. Bifurcation points and
bifurcation directions are derived in detail, which prove to be
consistent with the previous bifurcation diagram. Numerical
simulations and experimental results are given to verify the
theoretical analysis. Hopf bifurcation analysis can explain and
predict the periodical orbit (oscillation) in Chen circuit with
direct time delay feedback. Bifurcation boundaries are derived using
the Hopf bifurcation analysis, which will be helpful for determining
the parameters in the stabilisation of the originally chaotic
circuit.

In this paper, the asymptotical p-moment stability of
stochastic impulsive differential equations is studied and a
comparison theory to ensure the asymptotical p-moment stability of
the trivial solution is established, which is important for studying
the impulsive control and synchronization in stochastic systems. As
an application of this theory, we study the problem of chaos
synchronization in the Chen system excited by parameter white-noise
excitation, by using the impulsive method. Numerical simulations
verify the feasibility of this method.

A crisis in a Duffing--van del Pol system with fuzzy
uncertainties is studied by means of the fuzzy generalised cell
mapping (FGCM) method. A crisis happens when two fuzzy attractors
collide simultaneously with a fuzzy saddle on the basin boundary as
the intensity of fuzzy noise reaches a critical point. The two fuzzy
attractors merge discontinuously to form one large fuzzy attractor
after a crisis. A fuzzy attractor is characterized by its global
topology and membership function. A fuzzy saddle with a complicated
pattern of several disjoint segments is observed in phase space. It
leads to a discontinuous merging crisis of fuzzy attractors. We
illustrate this crisis event by considering a fixed point under
additive and multiplicative fuzzy noise. Such a crisis is fuzzy
noise-induced effects which cannot be seen in deterministic
systems.

This paper presents a new chaotic Hopfield network with
a piecewise linear activation function. The dynamic of the network is
studied by virtue of the bifurcation diagram, Lyapunov exponents
spectrum and power spectrum. Numerical simulations show that the
network displays chaotic behaviours for some well selected
parameters.

In this paper, the problem of generalised synchronisation
of two different chaotic systems is investigated. Some less
conservative conditions are derived using linear matrix inequality
other than existing results. Furthermore, a simple adaptive control
scheme is proposed to achieve the generalised synchronisation of chaotic
systems. The proposed method is simple and easy to implement in
practice and can be applied to secure communications. Numerical
simulations are also given to demonstrate the effectiveness and
feasibility of the theoretical analysis.

In this paper, a chaos system and proportional
differential control are both used to detect the frequency of an
unknown signal. In traditional methods the useful signal is obtained
through the Duffing equation or other chaotic oscillators. But these
methods are too complex because of using a lot of chaos oscillators.
In this paper a new method is presented that uses the R?ssler
equation and proportional differential control to detect a weak
signal frequency. Substituting the detected signal frequency into
the R?ssler equation leads the R?ssler phase state to be
considerably changed. The chaos state can be controlled through the
proportional differential method. Through its phase diagram and
spectrum analysis, the unknown frequency is obtained. The simulation
results verify that the presented method is feasible and that the
detection accuracy is higher than those of other methods.

The Shilnikov sense Smale horseshoe chaos in a simple 3D
nonlinear system is studied. The proportional integral derivative
(PID) controller is improved by introducing the quadratic and cubic
nonlinearities into the governing equations. For the discussion of
chaos, the bifurcate parameter value is selected in a reasonable
regime at the requirement of the Shilnikov theorem. The analytic
expression of the Shilnikov type homoclinic orbit is accomplished.
It depends on the series form of the manifolds surrounding the
saddle-focus equilibrium. Then the methodology is extended to
research the dynamical behaviours of the simplified
solar-wind-driven-magnetosphere-ionosphere system. As is
illustrated, the Lyapunov characteristic exponent spectra of the two
systems indicate the existence of chaotic attractor under some
specific parameter conditions.

The dynamics character of a two degree-of-freedom
aeroelastic airfoil with combined freeplay and cubic stiffness
nonlinearities in pitch submitted to supersonic and hypersonic flow
has been gaining significant attention. The Poincaré mapping
method and Floquet theory are adopted to analyse the limit cycle
oscillation flutter and chaotic motion of this system. The result
shows that the limit cycle oscillation flutter can be accurately
predicted by the Floquet multiplier. The phase trajectories of both
the pitch and plunge motion are obtained and the results show that
the plunge motion is much more complex than the pitch motion. It is
also proved that initial conditions have important influences on the
dynamics character of the airfoil system. In a certain range of
airspeed and with the same system parameters, the stable limit cycle
oscillation, chaotic and multi-periodic motions can be detected
under different initial conditions. The figure of the Poincaré
section also approves the previous conclusion.

According to random walk, in this paper, we propose a new
traffic model for scheduling trains on a railway network. In the
proposed method, using some iteration rules for walkers, the
departure and the arrival times of trains at each station are
determined. We test the proposed method on an assumed railway
network. The numerical simulations and the analytical results
demonstrate that the proposed method provides an effective tool for
scheduling trains. Some characteristic behaviours of train movement
can be reproduced, such as train delay.

A stochastic dynamical system with double singularities
driven by non-Gaussian noise is investigated. The Fokker--Plank
equation of the system is obtained through the path-integral
approach and the method of transformation. Based on the definition
of Shannon's information entropy and the Schwartz inequality
principle, the upper bound for the time derivative of entropy is
calculated both in the absence and in the presence of
non-equilibrium constraint. The present calculations can be used to
interpret the effects of the system dissipative parameter, the
system singularity strength parameter, the noise correlation time
and the noise deviation parameter on the upper bound.

The phase modulation and the closed-loop controller can
generate electrical crosstalk-coupling in digital closed-loop fibre
optic gyro. Four electrical cross-coupling paths are verified by
the open-loop testing approach. It is found the variation of ramp
amplitude will lead to the alternation of gyro bias. The amplitude
and the phase parameters of the electrical crosstalk signal are measured
by lock-in amplifier, and the variation of gyro bias is confirmed to
be caused by the alternation of phase according to the amplitude of
the ramp. A digital closed-loop fibre optic gyro electrical
crosstalk-coupling model is built by approximating the electrical
cross-coupling paths as a proportion and integration segment. The
results of simulation and experiment show that the modulation signal
electrical crosstalk-coupling can cause the dead zone of the gyro when a
small angular velocity is inputted, and it could also lead to a
periodic vibration of the bias error of the gyro when a large angular
velocity is inputted.

To simulate the intense bunched beam transport, a computer
program LEADS-3D has been developed. The particle trajectories are
analysed with the Lie algebraic method. The third order
approximation of the trajectory solutions is made with space charge
forces off, and the second order approximation is made with space
charge forces on. The particle distribution in the 3D ellipsoid is
uniform or Gaussian. Most of the conventional beam optical elements
are incorporated in the code. The optimization procedures are
provided to fit the beam lines to satisfy the given optical
conditions.

The remaining challenges, confronting high-power microwave
(HPM) sources and pulsed power generators, stimulate the
developments of robust relativistic electron beam sources. This
paper presents a carbon fibre cathode which is tested in a single
pulsed power generator. The distribution and the development of
cathode plasma are observed by time-and-space resolved diagnostics,
and the uniformity of electron beam density is checked by taking
x-ray images. A quasistationary behaviour of cathode plasma
expansion is observed. It is found that the uniformity of the
extracted electron beam is satisfactory in spite of individual
plasma jets on the cathode surface. These results show that carbon
fibre cathodes can provide a positive prospect for developing
a high-quality electron beam.

We study the effect of Landau--Zener (LZ) tunneling caused
by the varying sweeping rate of the external field, and solve the
problem about the LZ tunneling rate among many levels. The LZ
tunneling rate is essentially changed by the unsteady variation of
the time-dependent sweeping field and is different from the steadily
varying sweeping field, which makes the particles in lower states
transit periodically to upper states within a finite time.

Using the algebraic dynamical method, this paper
investigates the laser cooling of a moving two-level atom coupled to
a cavity field. Analytical solutions of optical forces and the
cooling temperatures are obtained. Considering Rb atoms as an
example, it finds that the numerical results are relevant to the recent
experimental laser cooling investigations.

Wave packet dynamics of the Li_{2} molecule are investigated
by using the time-dependent quantum wave packet method, and the
time-resolved photoelectron spectra of the Li_{2} molecule are
calculated. The time-resolved wave packet theory is used to
reasonably interpret the phenomena of the photoelectron spectra for
different parameters. Our calculation shows that the loss of the
wave packets in the shelf state area of E{ }^1\Sigma_{g}^ +
plays a prominent role in the process of photoionization with the
increase of the delay time. Moreover, the oscillation of the wave
packet on the E{ }^1\Sigma_{g}^ + curve symbolizes a
decreasing process of energy.

The molecular structures and the vibrational frequencies
of uranium hexahalides UX_{6 } (x=F, Cl, Br and I) molecules
are investigated by using local density approximation (LDA) and
generalised gradient approximation (GGA) functions (BP, BLYP and
RPBE) in combination with two different relativistic methods (scalar
and scalar+spin--orbit relativistic effects). The calculated results
show that the differences are trivial between scalar and
scalar+spin--orbit relativistic methods. The vibrational frequencies
are also compared with existing experimental values, and overall,
the RPBE approach gives the smallest error. The bond dissociation
energies (BDEs) of UX_{6} are computed by using the RPBE
function, thereby obtaining exact vibrational frequencies. In
addition, the calculated magnitudes of the spin--orbit effect on the BDE
of UX_{6 } (x=F, Cl, Br, and I) are found to be approximately
--0.3198, --0.3218, --0.3609 and --0.4415~eV, respectively.

This paper utilizes multireference configuration
interaction theory to calculate the lifetime of A^{2}\Pi _{\rm u}
state for nitrogen molecular ion N_{2}^{ + }. It obtains the
transition moment function for A^{2}\Pi _{\rm u} \to x^{2}\Sigma
_{g}^{ + }, Franck--Condon factors between vibrational levels
of the two states. The calculated lifetimes are 16.81, 14.62, 13.10,
12.18, 11.40, and 11.64~μ s for v'=0, 1, 2, 3, 4, 5
vibrational levels of A^{2}\Pi _{\rm u} state, respectively, which
are in excellent agreement with available experimental values.

This paper theoretically investigates the coherent phase control in
electron--argon scattering assisted by a bichromatic laser field.
The laser field is composed of a fundamental component and its
second harmonic. The incoming and out going states of electron are
described by the Volkov wave functions, and the electron--target
interaction is treated as a screening potential. Numerical results
for differential cross section of multiphoton processes vs the
phase difference between the two components of laser field are
discussed
for several scattering angles and
impact energies.

The possible geometrical and the electronic structures of
small Mg_{n}Ni (n=1-7) clusters are optimised by the density
functional theory with a LANL2DZ basis set. The binding energy, the
energy gap, the electron affinity, the dissociation energy and the
second difference in energy are calculated and discussed. The
properties of Mg_{n}Ni clusters are also discussed when the number
of Mg atom increases.

Employing first-principles methods, based on the density function theory, and using the LANL2DZ basis sets, the ground-state geometric, the stable and the electronic properties of Au_{n-2}Y_{2} clusters are investigated in this paper. Meanwhile, the differences in property among pure gold clusters, pure yttrium
clusters, gold clusters doped with one yttrium atom, and gold clusters doped with two yttrium atoms are studied. We find that when gold clusters are doped by two yttrium atoms, the odd--even
oscillatory behaviours of Au_{n-1}Y and Au_{n} disappear.
The properties of Au_{n-2}Y_{2} clusters are close to those of
pure yttrium clusters.

This paper uses the density functional theory under
generalised gradient approximation to analyse the stability,
frontier orbitals, bond character, and static linear polarizability
of H_{20}@C_{80}F_{60}, which has not been isolated, as well
as those of the synthesised H_{20}@C_{80}F_{60}. The
H_{20}@C_{80}F_{60} should be considerably stable by analysing
its energy and aromaticity. The inside H and outside x will play
different role in the chemical reaction involving
H_{20}@C_{80}F_{60} (X= H and F). The covalence of C--H bond
is in the order that the inside C--H bond of
H_{20}@C_{80}F_{60}> the inside C--H bond of
H_{20}@C_{80}F_{60}> the outside C--H bond of
H_{20}@C_{80}F_{60}, whereas the C--F bond of
H_{20}@C_{80}F_{60} have both the covalent and ionic
characters. The static linear polarizabilities of C_{80} and
H_{20}@C_{80}X_{60} (X= H and F) are all isotropic.

This paper uses the generalised gradient approximation
based on density functional theory to analyse the geometric
structure and properties of the 3d transition metal atom doped
endohedral fullerene M@C_{20}F_{20} (M= Sc--Ni). The
geometric optimization shows that the cage centre is the most stable
position for M, forming the structure named as
M@C_{20}F_{20}-4. The inclusion energy, zero-point energy, and
energy gap calculations tell us that Ni@C_{20}F_{20}-4 should be
thermodynamically and kinetically stablest. M@C_{20}F_{20}-4
(M= Sc--Co) possesses high magnetic moments varied from 1 to
6~μ_{B}, while Ni@C_{20}F_{20}-4 is nonmagnetic. The
Ni--C bond in Ni@C_{20}F_{20}-4 contains both the covalent and
ionic characters.

The static large field of the view polarization interference
imaging spectrometer is based on the modified Savart polariscope.
There appears a dispersion between the ordinary ray and extraordinary
ray when light passes through the modified Savart polariscope. The
dispersion greatly influences the intensities and the results of the
interferogram and target image in the static large field of the view
polarization interference imaging spectrometer. At the same time,
the incident angle determines the dispersion. When the light goes
through the modified Savart polariscope, the dispersion occurs in
the left plate, the half-wave plate and the right plate of the
modified Savart polariscope. Using the extension of Snell's law, the
dispersion in the crystal is theoretically calculated and
numerically simulated separately. The relationship curve between
incident angle and the dispersion is obtained by simulation.

A far-field optical lithography is developed in this
paper. By designing the structure of a far-field optical superlens,
lithographical resolution can be improved by using a
conventional UV light source. The finite different time domain
numerical studies indicate that the lithographic resolution at 50~nm
line width is achievable with the structure shown in this paper by
using 365~nm wavelength light, and the light can be transferred to a
far distance in the photoresist.

This paper proposes a theoretical analysis for the
characteristics of an external cavity Nd:YAG laser with feedback of
multiple-beam interference, which is induced by the multi-reentrance
of the light from the external Fabry--Perot cavity. The theoretical
model considers the multiple beam interference of the external
Fabry--Perot cavity. It is found that the optical feedback signals
are distorted to pulse waveforms instead of the sinusoidal ones in
conventional feedback. The experimental results are in good
agreement with the theoretical analysis. The obtained theoretical
and experimental results can advance the development of a laser
feedback interferometer.

This paper investigates the generation of self-organized
surface structures on amorphous alloys by vortex femtosecond laser
pulses. The scanning electron microscope characterizations show that
the as-formed structures are periodic ripples, aperiodic ripples,
and `coral-like' structures. Optimal conditions for forming these
surface structures are determined in terms of pulses number at a
given pulse energy. The applicable mechanism is suggested to
interpret the formation and evolution of the `coral-like'
structures.

We propose a scheme for controllably implementing an
N-qubit phase gate by one step within a ground-state subspace of
N three-state atoms trapped in a cavity through a double Raman
passage. We can extend our scheme to the realisation of an arbitrary
N-qubit phase gate by appropriately adjusting coupling strengths
and detunings between atoms and external driving fields. The
advantage of this one-step scheme is its robustness against
decoherence.

We discuss quantum fluctuation in excited states (named
thermo number states) of mesoscopic LC circuits at a finite
temperature. By introducing the coherent thermo state into the
thermo field dynamics pioneered by Umezawa and using the natural
representation of thermo squeezing operator we can concisely derive
the fluctuation. The result shows that the noise becomes larger when
either temperature or the excitation number increases.

This paper proposes a simple scheme to generate a
four-atom entangled cluster state in cavity quantum electrodynamics.
With the assistantce of a strong classical field the cavity is only
virtually excited and no quantum information will be transferred
from the atoms to the cavity during the preparation for a four-atom
entangled cluster state, and thus the scheme is insensitive to the
cavity field states and cavity decay. Assuming that deviation of
laser intensity is 0.01 and that of simultaneity for the interaction
is 0.01, it shows that the fidelity of the resulting four-atom
entangled cluster state is about 0.9886. The scheme can also be
used to generate a four-ion entangled cluster state in a hot
trapped-ion system. Assuming that deviation of laser intensity is
0.01, it shows that the fidelity of the resulting four-ion entangled
cluster state is about 0.9990. Experimental feasibility for
achieving this scheme is also discussed.

Using a stimulated parametric down-conversion process
combined with a conventional detector, we theoretically propose a
scheme to realize the stimulated emission-based detector, and
investigate the antinormally ordered correlation function and Fano
factor for the coherent field based on it. Such a detection has
advantages over the normally ordered one especially when the
intensity of the field is weak.

We present an experimental investigation of a
filamentation-assisted fourth-order nonlinear optical process in KTP
crystals pumped by intense 1.53~eV (807~nm) femtosecond laser
pulses. Femtosecond light pulses at 2.58~eV (480~nm) are generated
by the fourth-order nonlinear polarization (P^{4}(ω _{2} ) =
χ ^{4}(ω _{2} ,ω ,ω ,ω ,- ω _{1}
)E^{3}(ω )E^{*} (ω _{1} ), where E(ω ) corresponds to
the pump frequency and E(ω _{1} ) to the supercontinuum
generated through filamentation). If the system is seeded by a laser
beam at ω _{1} or ω _{2} and there are spatial and
temporal overlaps with the pump beam, E(ω _{1} ) and E(ω
_{2} ) are simultaneously amplified. When the intensity of the seed
laser beam exceeds a certain intensity threshold, the contribution
of P^{4}(ω ) = χ ^{4}(ω ,ω _{1} ,ω _{2} ,-ω, - ω )E(ω _{1} )E(ω _{2} )(E^{*} (ω))^{2} becomes non-negligible, and the amplification weakens. The
conversion efficiency from the pump to the signal at 2.58~eV
(480~nm) attains to 0.1%.

This paper studies dispersion characteristics of the
transverse magnetic (TM) mode for two-dimensional unmagnetized
dielectric plasma photonic crystal by a modified plane wave method.
First, the cutoff behaviour is made clear by using the
Maxwell--Garnett effective medium theory, and the influences of
dielectric filling factor and dielectric constant on effective
plasma frequency are analysed. Moreover, the occurence of large gaps in
dielectric plasma photonic crystal is demonstrated by comparing the
skin depth with the lattice constant, and the influence of plasma
frequency on the first three gaps is also studied. Finally, by using
the particle-in-cell simulation method, a transmission curve in the
\Gamma -X direction is obtained in dielectric plasma photonic
crystal, which is in accordance with the dispersion curves
calculated by the modified plane wave method, and the large gap between
the transmission points of 27~GHz and 47~GHz is explained by
comparing the electric field patterns in particle-in-cell
simulation.

We investigate the deflection and the fluctuation of
stresses due to different sizes of granular material in a
cylindrical column. It is experimentally observed that the
saturation mass systemically increases with granule diameter . The
results indicate the shielding of vertical stress in silo is
varying. We show that the ratio between the horizontal and the
vertical stresses, K, decreases with the increase in grainule
diameter D. In addition, it has also been found that the presence
of larger granules leads to stronger stress fluctuation on the
bottom plate of silo.

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

A two-dimensional particle-in-cell simulation is used to
study the time-dependent evolution of the sheath surrounding a
prolate spheroid target during a high voltage pulse in plasma source
ion implantation. Our study shows that the potential contour lines
pack more closely in the plasma sheath near the vertex of the major
axis, i.e. where a thinner sheath is formed, and a non-uniform total
ion dose distribution is incident along the surface of the prolate
spheroid target due to the focusing of ions by the potential
structure. Ion focusing takes place not only at the vertex of the
major axis, where dense potential contour lines exist, but also at
the vertex of the minor axis, where sparse contour lines exist. This
results in two peaks of the received ion dose, locating at the
vertices of the major and minor axes of the prolate spheroid target,
and an ion dose valley, staying always between the vertices, rather
than at the vertex of the minor axis.

The interaction between intense femtosecond laser pulses
and hydrogen atomic clusters is studied by a simplified Coulomb
explosion model. The dependences of average proton kinetic energy on
cluster size, pulse duration, laser intensity and wavelength are
studied respectively. The calculated results indicate that the
irradiation of a femtosecond laser of longer wavelength on hydrogen
atomic clusters may be a simple, economical way to produce highly
kinetic hydrogen ions. The phenomenon suggests that the irradiation
of femtosecond laser of longer wavelength on deuterium atomic
clusters may be easier than that of shorter wavelength to drive
nuclear fusion reactions. The product of the laser intensity and the
squared laser wavelength needed to make proton energy saturated as a
function of the squared cluster radius is also investigated. The
proton energy distribution calculated is also shown and compared
with the experimental data. Our results are in agreement with the
experimental results fairly well.

In this paper, singular value decomposition (SVD) as a
filter-noise method is applied to electron cyclotron emission (ECE)
diagnostic signals. The decomposed vectors contain the information
about sawtooth such as the temporal vectors that show the sawtooth
period and the spatial vectors that indicate the inverse radius. The
propagation of electron heat pulse is investigated from electron
cyclotron emission signals by using the perturbation method in HT-7
tokamak. The heat diffusivities are obtained at different densities
in ohmic plasmas. The special result is that the heat diffusivity
becomes larger as the heat pulse propagates outwards
from the outside of the inverse radius.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

The researches on the structure of water and its changes
induced by solutes are of enduring interests. The changes of the local
structure of liquid water induced by NaCl solute under ambient
conditions are studied and presented quantitatively with some order
parameters and visualized with 2-body and 3-body correlation
functions. The results show that, after the NaCl are solvated, the
translational order t of water is decreased for the suppression of
the second hydration shells around H_{2}O molecules; the tetrahedral
order ｜q｜ of water is also decreased and its favorite
distribution peak moves from 0.76 to 0.5. In addition, the
orientational freedom k and the diffusion coefficient D of water
molecules are reduced because of new formed hydrogen-bonding
structures between water and solvated ions.

Physical and chemical phenomena of low-energy ion
irradiation on solid surfaces have been studied systematically for
many years, due to the wide applications in surface modification,
ion implantation and thin-film growth. Recently the bombardment of
nano-scale materials with low-energy ions gained much attention.
Comared to bulk materials, nano-scale materials show different
physical and chemical properties. In this article, we employed
molecular dynamics simulations to study the damage caused by
low-energy ion irradiation on copper nanowires. By simulating the ion
bombardment of 5 different incident energies, namely, 1~keV, 2~keV,
3~keV, 4~keV and 5~keV, we found that the sputtering yield of
the incident ion is linearly proportional to the energies of incident
ions. Low-energy impacts mainly induce surface damage to the
nanowires, and only a few bulk defects were observed. Surface
vacancies and adatoms accumulated to form defect clusters on the
surface, and their distribution are related to the type of crystal
plane, e.g. surface vacancies prefer to stay on (100) plane, while
adatoms prefer (110) plane. These results reveal that the size
effect will influence the interaction between low-energy ion and
nanowire.

This paper applies a density functional theory (DFT) and
grand canonical Monte Carlo simulations (GCMC) to investigate the
physisorptions of molecular hydrogen in single-walled BC_{3}
nanotubes and carbon nanotubes. The DFT calculations may provide
useful information about the nature of hydrogen adsorption and
physisorption energies in selected adsorption sites of these two
nanotubes. Furthermore, the GCMC simulations can reproduce their
storage capacity by calculating the weight percentage of the
adsorbed molecular hydrogen under different conditions. The present
results have shown that with both computational methods, the
hydrogen storage capacity of BC_{3} nanotubes is superior to that
of carbon nanotubes. The reasons causing different behaviour of
hydrogen storage in these two nanotubes are explained by using their
contour plots of electron density and charge-density difference.

Based on a damage evolution equation and a critical damage
function model, this paper has completed the numerical simulation of
ductile spall fracture. The free-surface velocity and damage
distribution have been used to determine jointly the physical
parameters D_{l} (the critical linking damage), D_{f}
(the critical fracturing damage) and k (the softening rate of
critical damage function model）of the critical damage function
model, which are 0.11, 0.51 and 0.57 respectively. Results indicate
that the parameters determined by any of shots could be applicable
to the rest of other shots, which is convincing proof for the
universal property of critical damage function. In our experiments,
the shock pressure is about 1~GPa to 2.5~GPa. For the reason of
limited pressure range, there are still some limitations in the
methods of present analysis. Moreover, according to the damage
evolution characteristic of pure aluminum obtained by experiments,
two critical damages are obtained, which are 0.11 and 0.51
respectively. The results are coincident with the experimental ones,
which indicate that the critical growth behaviour of damage occurs
in the plastic metal under dynamic loading.

We present the growth of GaN epilayer on Si (111)
substrate with a single AlGaN interlayer sandwiched between the GaN
epilayer and AlN buffer layer by using the metalorganic chemical
vapour deposition. The influence of the AlN buffer layer thickness
on structural properties of the GaN epilayer has been investigated
by scanning electron microscopy, atomic force microscopy, optical
microscopy and high-resolution x-ray diffraction. It is found that
an AlN buffer layer with the appropriate thickness plays an important
role in increasing compressive strain and improving crystal quality
during the growth of AlGaN interlayer, which can introduce a more
compressive strain into the subsequent grown GaN layer, and
reduce the crack density and threading dislocation density in GaN
film.

Polycrystalline ferroelectric
Bi_{3.25}La_{0.75}Ti_{3}O_{12} thin films are prepared on
Pt/Ti/SiO_{2}/Si substrates by the conventional metalorganic
decomposition method. It is observed that with the increase of
switching pulse width, the remnant polarisation and the coercive
field increase. A wider switching pulse can result in poorer
fatigue properties, which comes from more charged defects diffusing
to and being trapped on domain walls. On the other hand, when the
compressive stress is applied to films, the fatigue properties can
be improved. This phenomenon is due to the reorientation of domains
under stress.

This paper presents the results of unintentionally doped
4H-SiC epilayers grown on n-type Si-faced 4H-SiC substrates with 8°
off-axis toward the [11\overline 2 0] direction by low pressure
horizontal hot-wall chemical vapour deposition. Growth temperature
and pressure are 1580~°C and 10^{4}~Pa, respectively. Good surface
morphology of the sample is observed using atomic force
microscopy (AFM) and scanning electron microscopy (SEM). Fourier transform
infrared spectroscopy (FTIR) and x-ray diffraction (XRD) are used to
characterize epitaxial layer thickness and the structural quality of the
films respectively. The carrier concentration in the unintentional 4H-SiC
homoepitaxial layer is about 6.4×10^{14}~cm^{-3} obtained by
c--V measurements. Schottky barrier diodes (SBDs) are fabricated on the
epitaxial wafer in order to verify the quality of the wafer and to obtain
information about the correlation between background impurity and electrical
properties of the devices. Ni and Ti/4H-SiC Schottky barrier diodes with
very good performances were obtained and their ideality factors are 1.10 and 1.05
respectively.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

Switching the orientation of a vortex core by
spin-polarised pulse current introduces a promising concept for the
reliable addressing of a single nanodisc element inside dense
arrays. In this paper, micromagnetic simulations are employed to
study the vortex core switching behaviour excited by a short
in-plane Gaussian current pulse. We find that both the switching
mechanism and the switching time are not sensitive to changes in
the phenomenological parameters of spin-torque nonadiabaticity and
Gilbert damping. The switching time, however, strongly depends on
the current strength. In addition, we have theoretically predicted
the parameter range of current pulses to achieve a single
switching event.

The effect of Nb content on the martensitic transformation
of NbRu high-temperature shape memory alloys is investigated by
experiments and first-principles calculations. We calculate the
lattice parameters, density of states, charge density, and heats of
formation of Nb_{50+x}Ru_{50-x} β phase. The
results show that an increase in Nb content increases the stability
of Nb_{50+x}Ru_{50-x} β phase, leading to a
significant decrease of the β to β' martensitic
transformation temperature. In addition, the mechanism of the
effects of Nb content on phase stability and martensitic
transformation temperature is studied on the basis of
electronic structure.

With the help of the ab initio full-potential
linearized augmented plane wave (FPLAPW) method, calculations of
the electronic structure and linear optical properties are carried
out for red HgI_{2} and yellow HgI_{2}. It is found that
the red HgI_{2} has a direct gap of 1.22834 eV and the yellow
HgI_{2} has an indirect gap of 2.11222 eV. For the red
HgI_{2}, the calculated optical spectra are qualitatively in agreement with the
experimental data. Furthermore, the origins of the
different peaks of ε _{2} (ω ) are discussed. Our
calculated anisotropic dielectric function of the red HgI_{2} is
a nice match with the experimental results. Our calculated results
are able to reproduce the overall trend of the experimental
reflectivity spectra. Although no comparable experimental and
theoretical results are available, clearly, the above proves the
reliability of our calculations, suggesting that our calculations
should be convincing for the yellow HgI_{2}. Finally, the
different optical properties are discussed.

The geometrical structures of Cd_{0.75}TM_{0.25}Se (TM
= Ti, V, Cr and Mn) are optimized, and then their electric and
magnetic properties are investigated by performing
first-principles calculations within the generalized gradient
approximation for the exchange--correlation function based on
density functional theory. Cd_{0.75}TM_{0.25}Se (TM = Ti and V)
are found to have high spin-polarization near 100% at the Fermi
level. Cd_{0.75}TM_{0.25}Se (TM = Cr and Mn) are half-metallic
ferromagnets whose spin-polarization at the Fermi level is
absolutely +100%. The supercell magnetic moments of
Cd_{0.75}Cr_{0.25}Se and Cd_{0.75}Mn_{0.25}Se are 4.00 and
5.00~μ_{B}, which arise mainly from Cr-ions and Mn-ions,
respectively. The half-metallicity of Cd_{0.75}Cr_{0.25}Se is
more stable than that of Cd_{0.75}Mn_{0.25}Se. The electronic
structures of Cr-ions and Mn-ions are Cr e_{g}^{2}↑
t_{2g}^{2}↑ and Mn e_{g}^{2}↑
t_{2g}^{3}↑, respectively.

The structure of a heterojunction made up of an (8, 0)
carbon nanotube and an (8, 0) boron nitride nanotube is achieved
through geometry optimization implemented in the CASTEP package. Based
on the optimized geometry, the model of the heterojunction is
established. Its transport properties are investigated by combining
the nonequilibrium Green's function with density functional
theory. Results show that both the lowest unoccupied molecular
orbital and the highest occupied molecular orbital mainly locate on
the carbon nanotube section. In the current--voltage characteristic
of the heterojunction, a rectification feature is revealed.

This paper utilizes multilayer organic light-emitting
diodes with a thin layer of dye molecules to study the mechanism of
charge trapping under different electric regimes. It demonstrates
that the carrier trapping was independent of the current density in
devices using fluorescent material as the emitting molecule while this
process was exactly opposite when phosphorescent material was used.
The triplet--triplet annihilation and dissociation of excitons into
free charge carriers was considered to contribute to the decrease in
phosphorescent emission under high electric fields. Moreover, the
fluorescent dye molecule with a lower energy gap and ionized
potential than the host emitter was observed to facilitate the
carrier trapping mechanism, and it would produce photon emission.

This paper presents two n-channel organic heterojunction
transistors with modified insulator by using
hexadecafluorophthalocyaninatocopper (F_{16}CuPc)/copper
phthalocyanine (CuPc) and F_{16}CuPc/pentacene as the active
layers. Compared with a single-layer device, it reports that an
improved field-effect mobility and a 6-fold higher drain current are
observed. The highest mobility of 0.081~cm^{2}/(V.s) was
obtained from F_{16}CuPc/CuPc heterojunction devices. This result
is attributed to the dual effects of the organic heterojunction and
interface modification. Furthermore, for two heterojunction devices,
the performance of the F_{16}CuPc/CuPc-based transistor is better than
that of F_{16}CuPc/pentacene. This is attributed to the
morphologic match of two organic components.

We investigate several models of a one-dimensional chain
coupling with surrounding atoms to elucidate disorder-induced
delocalization in quantum wires, a peculiar behaviour against
common wisdom. We show that the localization length is enhanced by
disorder of side sites in the case of strong disorder, but in the
case of weak disorder there is a plateau in this dependence. The
above behaviour is the conjunct influence of the coupling to the
surrounding atoms and the antiresonant effect. We also discuss
different effects and their physical origin of different types of
disorder in such systems. The numerical results show that
coupling with the surrounding atoms can induce either the
localization or delocalization effect depending on the values of
parameters.

This paper presents an accurate analytical model of the random telegraph signal (RTS) noise time-constant ratio (\bar {τ}_{c}/ \bar {τ}_{e} for RTS noise in nano-MOSFETs, in which the Coulomb-blockade effect on trapping and detrapping processes was taken into account. Based on this new model, the depth of the trap responsible for RTS noise in a sample n-type nano-MOSFET is extracted. The results show that large errors will be introduced to the calculated trap depth when the Coulomb-blockade effect is neglected.

We investigate the thermoelectric-transport properties of
metal/graphene/metal hetero-structure. We use a single band
tight-binding model to present the two-dimensional electronic band
structure of graphene. Using the Landauer--Butticker formula and taking
the coupling between graphene and the two electrodes into account,
we can calculate the thermoelectric potential and current versus
temperature. It is found that in spite of metal electrodes, the
carrier type of graphene determines the electron motion direction
driven by the difference in temperature between the two electrodes,
while for n type graphene, the electrons move along the thermal
gradient, and for p type graphene, the electrons move against the
thermal gradient.

This paper proposes a universal spin-dependent variable
range hopping theoretical model to describe various experimental
transport phenomena observed in wide-band-gap oxide ferromagnetic
semiconductors with high transition metal concentration. The
contributions of the `hard gap' energy, Coulomb interaction,
correlation energy, and exchange interaction to the electrical
transport are considered in the universal variable range hopping
theoretical model. By fitting the temperature and magnetic field
dependence of the experimental sheet resistance to the theoretical
model, the spin polarization ratio of electrical carriers near the Fermi
level and interactions between electrical carriers can be
obtained.

This paper studies the electronic transport property
through a square potential barrier in armchair-edge graphene
nanoribbon (AGNR). Using the Dirac equation with the continuity
condition for wave functions at the interfaces between regions with
and without a barrier, we calculate the mode-dependent transmission
probability for both semiconducting and metallic AGNRs,
respectively. It is shown that, by some numerical examples, the
transmission probability is generally an oscillating function of the
height and range of the barrier for both types of AGNRs. The main
difference between the two types of systems is that the magnitude of
oscillation for the semiconducting AGNR is larger than that for
the metallic one. This fact implies that the electronic transport
property for AGNRs depends sensitively on their widths and edge
details due to the Dirac nature of fermions in the system.

The spin-dependent conductance and magnetoresistance ratio
(MRR) for a semiconductor heterostructures consisting of two
magnetic barriers with different height and space have been
investigated by the transfer-matrix method. It is shown that the
splitting of the conductance for parallel and antiparallel
magnetization configurations results in tremendous spin-dependent
MRR, and the maximal MRRs reach 5300\% and 3800\% for the magnetic
barrier spaces W=81.3 and 243.9~nm, respectively. The obtained
spin-filtering transport property of nanostructures with magnetic
barriers may be useful to magnetic-barrier-based spintronics.

This paper applies a novel quad-layer resist and e-beam
lithography technique to fabricate a GaAs-based InAlAs/InGaAs
metamorphic high electron mobility transistor (HEMT) grown by metal
organic chemical vapour deposition (MOCVD). The gate length of
the metamorphic HEMT was 150~nm, the maximum current density was
330~mA/mm, the maximum transconductance was 470~mS/mm, the threshold
voltage was -0.6~V, and the maximum current gain cut-off frequency
and maximum oscillation frequency were 102~GHz and 450~GHz,
respectively. This is the first report on tri-termination devices
whose frequency value is above 400~GHz in China. The excellent
frequency performances promise the possibility of metamorphic HEMTs
grown by MOCVD for millimetre-wave applications, and more
outstanding device performances would be obtained after optimizing
the material structure, the elaborate T-gate and other device
processes further.

A new partial-SOI (PSOI) high voltage device structure
called a CI PSOI (charge island PSOI) is proposed for the first time
in this paper. The device is characterized by a charge island layer
on the interface of the top silicon layer and the dielectric buried layer in
which a series of equidistant high concentration n^{+}-regions
is inserted. Inversion holes resulting from the vertical electric field
are located in the spacing between two neighbouring n^{+}-regions
on the interface by the force with ionized donors in the
undepleted n^{+}-regions, and therefore effectively enhance the
electric field of the dielectric buried layer (E_{I}) and increase
the breakdown voltage (BV), thereby alleviating the self-heating effect
(SHE) by the silicon window under the source. An analytical model of
the vertical interface electric field for the CI PSOI is presented
and the analytical results are in good agreement with the 2D
simulation results. The BV and E_{I} of the CI PSOI LDMOS increase to
631~V and 584~V/μ m from 246~V and 85.8~V/μ m for the
conventional PSOI with a lower SHE, respectively. The effects of the
structure parameters on the device characteristics are analysed for the
proposed device in detail.

We report that fully transparent resistive random access
memory (TRRAM) devices based on ITO/TiO2/ITO sandwich structure,
which are prepared by the method of RF magnetron sputtering, exhibit
excellent switching stability. In the visible region (400--800~nm in
wavelength) the TRRAM device has a transmittance of more than
80%. The fabricated TRRAM device shows a bipolar resistance
switching behaviour at low voltage, while the retention test and
rewrite cycles of more than 300,000 indicate the enhancement of
switching capability. The mechanism of resistance switching is
further explained by the forming and rupture processes of the
filament in the TiO_{2} layer with the help of more oxygen vacancies
which are provided by the transparent ITO electrodes.

Based on the density functional theory (DFT), using the
scheme of the linearized augmented plane wave and the improved local
orbital (APW + lo), the structure, the electronic bands and the
magnetism of superconducting compounds Ca_{1-x}k_{x}Fe_{2}As_{2} (x=0, 0.25, 0.5, 0.75, 1) are optimized
and calculated. The calculation results indicate that with
K-doping the lengths of the A, b axes can decrease, and the length
of the c axis, the volume, the energy of spin-down valence bands, and
the DOS at the Fermi level can increase, which leads the magnetic moment
of the system to increase.

The magneto-transport properties are investigated in
metamagnetic CoMnSi_{0.88}Ge_{0.12} alloy. By applying a
magnetic field or increasing temperature, a metamagnetic phase
transition from antiferromagnetic to ferromagnetic is observed in
this alloy. Around the metamagnetic phase transition,
CoMnSi_{0.88}Ge_{0.12} alloy exhibits a large and negative
magnetoresistance effect (～ 32%) under a magnetic field of
20~kOe (1~Oe = 79.5775~A/m), which is ascribed to the spin-dependent
scattering of conduction electrons.

The magnetocaloric properties of the
Gd_{5}Ge_{2.025}Si_{1.925}In_{0.05} compound have been
studied by x-ray diffraction, magnetic and heat capacity
measurements. Powder x-ray diffraction measurement shows that the
compound has a dominant phase of monoclinic
Gd_{5}Ge_{2}Si_{2}-type structure and a small quantity of
Gd_{5}(Ge,Si)_{3}-type phase at room temperature. At about 270 K,
this compound shows a first order phase transition. The isothermal
magnetic entropy change (Δ S_{M}) is calculated from the
temperature and magnetic field dependences of the magnetization and
the temperature dependence of MCE in terms of adiabatic temperature
change (Δ T_{ad}) is calculated from the isothermal
magnetic entropy change and the temperature variation in zero-field
heat-capacity data. The maximum Δ S_{M} is
-13.6~J.kg^{-1}.k^{-1} and maximum Δ T_{ad} is 13~K for the magnetic field change of 0--5~T. The Debye
temperature (θ_{D}) of this compound is 149~K and the
value of DOS at the Fermi level is 1.6 states/eV.atom from the low
temperature zero-field heat-capacity data. A considerable isothermal
magnetic entropy change and adiabatic temperature change under a field
change of 0--5~T jointly make the
Gd_{5}Ge_{2.025}Si_{1.925}In_{0.05} compound an attractive
candidate for a magnetic refrigerant.

This paper reports that a CoFe/IrMn bilayer was deposited by high vacuum magnetron sputtering on silicon wafer
substrate; the thermal relaxation of the CoFe/IrMn bilayer is investigated by means of holding the film in a negative saturation field at various temperatures. The exchange bias decreases with increasing period of time while holding the film in a negative saturation field at a given temperature. Increasing the temperature accelerates the decrease of exchange field. The results can be explained by the quantitative model of the nucleation and growth of antiferromagnetic domains suggested by Xi H W et al. [2007 Phys. Rev. B 75 014434], and it is believed that two energy barriers exist in the
investigated temperature range.

A hard/soft SmCo_{5}/ Fe nanocomposite magnetic bilayer
system is fabricated on x-ray transparent 100--200~nm thin
Si_{3}N_{4} films by magnetron sputtering. The microscopic
magnetic domain pattern and its behaviours during magnetization
reversal in the hard and the soft magnetic phases are studied
separately by element specific magnetic soft x-ray microscopy at a
spatial resolution of better than 25~nm. We observe that the domain
patterns for the soft and hard phases show coherent
behaviours in varying magnetic fields. We derive local M(H) curves
from the images of Fe and SmCo_{5} separately and find the
switches for hard and soft phases to be the same.

Ga^{+} ion irradiation is performed on the surfaces of
IrMn-based spin valves and the effects of ion irradiation on
the magnetisation reversal process and magnetoresistance (MR) are
investigated. The results show that the exchange bias field and
magnetoresistance ratio of the spin valve decrease with the increase
of ion dose. The width of the forward step between the free layer and
the pinned layer becomes gradually smaller with the increase of ion dose
whilst the recoil step tends to be narrower with ion dose increasing
up to 6× 10^{13} ions/cm^{2} and the step disappears
afterwards. Two peaks in the R--H curve are found to be
asymmetric.

La/Mn co-doped Bi_{4}Ti_{3}O_{12} ceramics,
Bi_{3.25}La_{0.75}Ti_{3-x}Mn_{x}O_{12} (x=0.02, 0.04,
0.06, 0.08), were prepared by the solid-state reaction method. The
influence of manganese substitution for the titanium part in
Bi_{3.25}La_{0.75}Ti_{3}O_{12} on the sintering behaviour,
microstructure, Raman spectra and electrical properties was
investigated. The experimental results show that the phase
composition of all samples with and without manganese doping,
sintered at 1000~°C, consists of a single phase with a
bismuth-layered structure belonging to the crystalline phase
Bi_{4}Ti_{3}O_{12}. There is no evidence of any impurity
phase, but a small change in crystallographic orientation is
observed. The Curie temperature of Bi_{3.25}La_{0.75}Ti_{3-x}Mn_{x}O_{12} ceramics is steadily shifted to lower
temperature with increasing Mn-doping content. Moreover, the remnant
polarisation (P_{r}) of Bi_{3.25}La_{0.75}Ti_{3-x}Mn_{x}O_{12} samples increases with Mn-doping content,
and the Bi_{3.25}La_{0.75}Ti_{2.92}Mn_{0.08}O_{12} sample
exhibits the largest P_{r} of 16.6~μ C/cm^{2}.

White organic light-emitting diodes with a blue emitting
material fluorene-centred ethylene-liked carbazole oligomer (Cz6F)
doped into polyvinyl carbazole (PVK) as the single light-emitting
layer are reported. The optical properties of Cz6F, PVK, and PVK:Cz6F
blends are studied. Single and double layer devices are fabricated
by using PVK: Cz6F blends, and the device with the configuration of
indium tin oxide (ITO)/PVK:Cz6F/ tris(8-hydroxyquinolinate)aluminium
(Alq_{3})/LiF/Al exhibits white light emission with Commission
Internationale de l'éclairage chromaticity coordinates of (0.30,
0.33) and a brightness of 402~cd/m^{2}. The investigation reveals
that the white light is composed of a blue--green emission
originating from the excimer of Cz6F molecules and a red emission
from an electroplex from the PVK:Cz6F blend films.

This paper reports that La-doped BiFeO_{3} (Bi_{1-x}La_{x}FeO_{3}, x=0, 0.1, 0.2, 0.3, 0.6, 0.8 and 1.0) were
studied by using micro-Raman spectroscopy and x-ray diffraction
(XRD). The XRD patterns indicate that the structure of Bi_{1-x}La_{x}FeO_{3} changes from rhombohedral BiFeO_{3} to
orthorhombic LaFeO_{3}. The results of Raman spectroscopy show
good agreement with the XRD results. Strikingly, the phonon peak at
around 610~cm^{-1} and the two-phonon peaks in the high
frequency range exist in all compounds and enhance with increasing
La substitution. The increasing intensity of the 610~cm^{-1}
peak is attributed to the changes in the FeO_{6} octahedron during
the rhombohedral--orthorhombic phase transition. The enhancements of
the two-phonon peaks are associated with the breakdown of the
cycloid spin configuration with the appearance of the orthorhombic
structure. These results indicate the existence of strong
spin--phonon coupling in Bi_{1-x}La_{x}FeO_{3}, which may
provide useful information for understanding the effects of La
content on the structural and magnetic properties of Bi_{1-x}La_{x}FeO_{3}.

Nanodevices using the photovoltaic effect of a single nanowire
have attracted growing interest. In this paper, we consider
potential applications of the photovoltaic effect to optical signal
coupling and optical power transmission, and report on the
realization of a heterojunction formed between WO_{2} and WO_{3} in a fine-wire having a diameter on the micrometer scale. Using a
laser beam of 514.5~nm as a signal source, the WO_{2}--WO_{3}
heterojunction yields a maximum output power of up to 37.4 pico watt
per heterojunction. Fast responses (less than a second) of both
photovoltaic voltage and current are also observed. In addition, we
demonstrate that it is a simple and effective way to adapt a
commercial Raman spectrometer for the combined functions of
fabrication, material characterization and photovoltaic measurement
of an optical signal coupler and optical power transmitter based on a
fine-wire. Our results show an attractive perspective of developing
nanowire or fine-wire elements for coupling optical signals into and
for powering a nanoelectronic or nano-optoelectronic integrated
circuit that works under the condition of preventing it from
directly electrically connecting with the optical coupler.

In this paper, the electroluminescence quenching mechanism
in a 5,6,11,12-tetraphenylnaphthacene (Rubrene) doped host--guest
system is studied by utilizing a specially designed organic
light-emitting diode with an emission layer consisting of a few
periodic host/guest structures. Tris-(8-hydroxyquinoline) aluminium
(Alq_{3}) and Rubrene are used as the host and the guest,
respectively. The thickness variation of the guest layer in each
period enables the study of the effect of molecule aggregation, and
the thickness variation of the host layer suggests a long range
quenching mechanism of dipole--dipole interaction. The long range
quenching mechanism is a F?rster process, and the F?rster
radius of Rubrene is between 3 and 10~nm.

8000 CROSSDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY

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