In this paper, we use a kind of univariate multiquadric
quasi-interpolation to solve a parabolic equation with overspecified
data, which has arisen in many physical phenomena. We obtain the
numerical scheme by using the derivative of the quasi-interpolation
to approximate the spatial derivative of the dependent variable and
a simple forward difference to approximate the temporal derivative
of the dependent variable. The advantage of the presented scheme is
that the algorithm is very simple so it is very easy to
implement. The results of the numerical experiment are presented and are
compared with the exact solution to confirm the good accuracy of the
presented scheme.

A new eight-dimensional Lie superalgebra is constructed
and two isospectral problems with six potentials are designed.
Corresponding hierarchies of nonlinear evolution equations, as well
as super-AKNS and super-Levi, are derived. Their super-Hamiltonian
structures are established by making use of the supertrace identity,
and they are integrable in the sense of Liouville.

A class of singularly perturbed initial boundary value
problems of reaction diffusion equations for the nonlinear boundary
condition with two parameters is considered. Under suitable
conditions, by using the theory of differential inequalities, the
existence and the asymptotic behaviour of the solution for the initial boundary
value problem are studied. The obtained solution indicates that
there are initial and boundary layers and the thickness of the
boundary layer is less than the thickness of the initial layer.

In this paper, we introduce an asymmetric payoff
distribution mechanism into the evolutionary prisoner's dilemma game
(PDG) on Newman--Watts social networks, and study its effects on the
evolution of cooperation. The asymmetric payoff distribution
mechanism can be adjusted by the parameter α: if α>0,
the rich will exploit the poor to get richer; if α<0, the
rich are forced to offer part of their income to the poor.
Numerical results show that the cooperator frequency monotonously
increases with α and is remarkably promoted when α>0.
The effects of updating order and self-interaction are also
investigated. The co-action of random updating and self-interaction
can induce the highest cooperation level. Moreover, we employ the Gini
coefficient to investigate the effect of asymmetric payoff
distribution on the the system's wealth distribution. This work may
be helpful for understanding cooperative behaviour and wealth
inequality in society.

Chaos game representation (CGR) is proposed as a
scale-independent representation for DNA sequences and provides
information about the statistical distribution of oligonucleotides
in a DNA sequence. CGR images of DNA sequences represent some kinds of
fractal patterns, but the common multifractal analysis based on the
box counting method cannot deal with CGR images perfectly. Here, the
wavelet transform modulus maxima (WTMM) method is applied to the
multifractal analysis of CGR images. The results show that the
scale-invariance range of CGR edge images can be extended to three
orders of magnitude, and complete singularity spectra can be
calculated. Spectrum parameters such as the singularity spectrum
span are extracted to describe the statistical character of DNA
sequences. Compared with the singularity spectrum span, exon
sequences with a minimal spectrum span have the most uniform
fractal structure. Also, the singularity spectrum parameters are
related to oligonucleotide length, sequence component and species,
thereby providing a method of studying the length polymorphism of
repeat oligonucleotides.

The Lie symmetries and conserved quantities of a
two-dimensional nonlinear diffusion equation of concentration are
considered. Based on the invariance of the two-dimensional nonlinear
diffusion equation of concentration under the infinitesimal
transformation with respect to the generalized coordinates and time,
the determining equations of Lie symmetries are presented. The Lie
groups of transformation and infinitesimal generators of this
equation are obtained. The conserved quantities associated with the
nonlinear diffusion equation of concentration are derived by
integrating the characteristic equations. Also, the solutions of the
two-dimensional nonlinear diffusion equation of concentration can be
obtained.

Cylindrical waveguides without end surfaces can serve as
two-dimensional resonant cavities. In such cavities the
electromagnetic oscillations corresponding to an eigenfrequency can
always be taken as TM or TE modes even when the walls have a finite
conductivity and the medium is absorptive. This paper obtains
analytic solutions to the field equations when the cylinder has a
circular cross section. Some nonperturbative conclusions are drawn
from the eigenvalue equation. Approximate analytic results for the
resonant frequencies are obtained when the absorption of the medium
is small and the walls are good conductors. Stability of the eigen
modes is discussed. Similar results for the coaxial line are
presented.

Utilizing a three-particle W state, we come up with a
protocol for the teleportation of an unknown two-particle entangled
state. It is shown that the teleportation can be deterministically
and exactly realized. Moreover, two-particle entanglement
teleportation is generalized to a system consisting of many
particles via a three-particle W state and a multi-particle W
state, respectively. All unitary transformations performed by the
receiver are given in a concise formula.

We present two kinds of exact vector-soliton solutions for
coupled nonlinear Schr?dinger equations with time-varying
interactions and time-varying harmonic potential. Using the
variational approach, we investigate the dynamics of the vector
solitons. It is found that the two bright solitons oscillate about
slightly and pass through each other around the equilibration state
which means that they are stable under our model. At the same time, we
obtain the opposite situation for dark--dark solitons.

We consider a two-qubit system described by the Heisenberg
XY model with Dzyaloshinski--Moriya (DM) anisotropic interaction
in a perpendicular magnetic field to investigate the relation
between entanglement, geometric phase and quantum phase transition
(QPT). It is shown that the DM interaction has an effect on the
critical boundary. The combination of entanglement and geometric
phase may characterize QPT completely. Their jumps mean that the occurrence
of QPT and inversely the QPT at the critical point at least
corresponds to a jump of one of them.

After the birth of quantum mechanics, the notion in physics that the frequency of light is the only factor that determines the energy of a single photon has played a fundamental role. However, under the assumption that the theory of Lewis--Riesenfeld invariants is applicable in quantum optics, it is shown in the present work that this widely accepted notion is valid only for light described by a time-independent Hamiltonian, i.e., for light in media satisfying the conditions,ε(t)=ε(0), μ(t)=μ(0), and σ(t)=0 simultaneously. The use of the Lewis--Riesenfeld invariant operator method in quantum optics leads to a marvelous result:the energy of a single photon propagating through time-varying linear media exhibits nontrivial time dependence without a change of frequency.

A scheme, based on the two two-level atoms resonantly
driven by the classical field separately trapped in two cavities
coupled by an optical fibre, for the implementation of remote
two-qubit gates is investigated. It is found that the quantum
controlled-phase and swap gates can be achieved with the assistance
of the classical field when there are detunings of the coupling quantum
fields. Moreover, the influence of the dissipation of the cavities
and the optical fibre is analysed while the spontaneous emission of
the atoms can be effectively suppressed by introducing Λ-type atoms.

Using the intermediate coordinate--momentum representation
|x>_{s,r}, we introduce a new Hadamard
transform. It is found that the operator U corresponding to this
transform can be considered as a combination of the Fresnel operator
F(r,s) and the Fourier transform operator F
by decomposing U. We also find that the matrix element
_{s,r}< x| U|f>
just corresponds to an optical scaled Fresnel--Fourier transform.

An experimentally feasible scheme for implementing
four-atom quantum dense coding of an atom--cavity system
is proposed. The cavity is only virtually excited and no quantum information will be
transferred from the atoms to the cavity. Thus the scheme is
insensitive to cavity decay and the thermal field. In the
scheme, Alice can send faithfully 4 bits of classical information to
Bob by sending two qubits. Generalized Bell states can be exactly
distinguished by detecting the atomic state, and quantum dense
coding can be realized in a simple way.

Based on the concept of concurrence, we have investigated the
entanglement dynamics of two two-level atoms coupled to a
single-mode cavity field with inhomogeneous couplings. We find that,
for some initial states, the inhomogeneous couplings not only
induce but also enhance the entanglement in the process of its
evolution. In addition, considering the intrinsic decoherence
proposed by Milburn, we also find that a proper value of
inhomogeneous couplings can enhance the stationary entanglement, and
as a result, the destructive effect of intrinsic decoherence on
entanglement can be moderated by the inhomogeneous couplings.

A scheme to perfectly preserve an initial qubit state in
geometric quantum computation is proposed for a single-qubit geometric
quantum gate in a nuclear magnetic resonance system. At first, by
adjusting some magnetic field parameters, one can let the dynamic
phase be proportional to the geometric phase. Then, by controlling
the azimuthal angle in the initial state, we may realize a
geometric quantum gate whose fidelity is equal to one under
cyclic evolution. This means that the quantum information is no
distortion in the process of geometric quantum computation.

In this paper, we propose a classical secret broadcasting and
splitting joint protocol in a quantum scenario. With those genuinely
entangled states, the boss can always broadcast some of his secrets
and split some others to multi-receivers at the same time.
The efficiency of the joint protocol is also compared with that of two
separate ones which realise classical secret broadcasting and
classical secret splitting respectively, and based on the comparison
we can see the promising advantage of our joint protocol is that it
can realise the two tasks more efficiently and more conveniently.

A simple scheme is proposed to generate the W state of
N Λ-type neutral atoms trapped in an optical cavity via Raman
transition. Conditional on no photon leakage from the cavity, the
N-qubit W state can be prepared perfectly by turning on a classical
coupling field for an appropriate time. Compared with the previous
ones, our scheme requires neither individual laser addressing of
the atoms, nor demand for controlling N atoms to go through an
optical cavity simultaneously with a constant velocity. We
investigate the influence of cavity decay using the quantum jump
approach and show that the preparation time decreases and
the success probability increases with atom number because of
a collective enhancement of the coupling.

We study the eigenenergies and eigenfunctions of the
ground and first-excited states of an electron which is
strongly coupled to an LO-phonon in a quantum dot with a triangular
bound potential and Coulomb bound potential by using the Pekar
variational method. This system may be used as a two-level qubit.
Phonon spontaneous emission causes the decoherence of the qubit.
Numerical calculations are performed on the decoherence rate as a
function of the polar angle, the Coulomb binding parameter, the
coupling strength, the confinement length of the quantum dot and the
dispersion coefficient.

The macroscopic quantum entanglement in capacitively
coupled SQUID (superconducting quantum interference device)-based
charge qubits is
investigated theoretically. The entanglement characteristic is discussed by
employing the quantum Rabi oscillations and the concurrence. An
interesting conclusion is obtained, i.e., the magnetic fluxes
Ф_{x1} and Ф_{x2} through the superconducting
loops can adjust the entanglement degree between the qubits.

This paper uses the background field method to calculate
one-loop divergent corrections to the gauge field propagators in
noncommutative U(1) gauge theory with scalar fields. It shows that
for a massless scalar field, the gauge field propagators are
renormalizable to θ^{2}-order, but for a massive scalar field they
are renormalizable only to θ-order.

In this paper we investigate the evolution of the
cosmology model with dark energy interacting with massive neutrinos
and dark matter. Using the numerical method to investigate the
dynamical system, we find that the stronger the interaction between
dark energy and dark matter, the lower the ratio of dark matter
in the universe is; also, the stronger the interaction between dark
energy and massive neutrinos, the lower the ratio of massive
neutrinos in the universe is. On the other hand, the interaction
between dark energy and dark matter or massive neutrinos has an
effect on disturbing the universe's acceleration; we also find that
our universe is still accelerating.

After considering the generalized uncertainty principle, we
discuss the quantum tunneling radiation of a five-dimensional
Schwarzschild anti de Sitter black hole. The radiation spectrum and
the correction value of the Bekenstein--Hawking entropy are derived.
In a five-dimensional black hole the one order correction term in the
Bekenstein--Hawking entropy correction term is proportional to the third
power of the area, and the logarithmic correction term is a two-order
small quantity. The correction term is related to the dimension
constant introduced in the generalized uncertainty principle. Because
the black hole entropy is not divergent, the lowest value of the
five-dimensional Schwarzschild anti de Sitter black hole horizon
radius is obtained. After considering the generalized uncertainty
principle, the radiation spectrum is still consistent with
normalization theory.

Taking a black hole as a black body system, using general
black body radiation theory, a Schwarzschild black hole and a
Kerr--Newman black hole are investigated respectively. It is
concluded that a black hole can be regarded as an ideal general
black body system exactly for the changing process only. However, a
stationary global black hole cannot be smoothly regarded as a general black
body system. A black hole has some special characteristics which
different from a general thermodynamics system. This conclusion means
that a black hole should be inherently dynamical, at least when it is
taken as a black body system.

This paper investigates the two-time intensity correlation
function of a two-mode ring laser system subjected to both pump
and quantum noises by stochastic simulation. It finds that the
decay rate of the intensity correlation function of one mode gets
faster with decreasing values of relevant parameters, i.e., the
coupling constant ξ, the cross-correlation coefficient λ
, the difference of the pump parameters Δa and the pump
parameter a_{1}; however, its variations get complex in the other
mode when relevant parameters are changed. The investigating results
also show that the effects of the mode competition on intensity
correlation function are obvious.

This paper investigates the correlation between stochastic
resonance (SR) and the average phase-synchronization time which is
between the input signal and the output signal in a bistable system
driven by colour-correlated noises. The results show that the output
signal-to-noise ratio can reach a maximum with the increase of the
average phase-synchronization time, which may be helpful for
understanding the principle of SR from the point of synchronization;
however, SR and the maximum of the average phase-synchronization
time appear at different optimal noise level, moreover, the effects
on them of additive and multiplicative noise are different.

We investigate stochastic resonance (SR) in the
FitzHugh--Nagumo system under combined bounded noise and weak
harmonic excitation. Taking a spectral amplification factor as a
signal-to-noise ratio, we show numerically that bounded noise can
induce SR by adjusting either the intensity of bounded noise or its
colour. Moreover, the increase of noise colour can enhance the SR
and make the peak of the SR shift toward lower noise intensities, which
is more feasible in practice. Since bounded noise is flexible to
model random excitation, these findings may have some potential
applications in engineering, neuroscience and biology.

This paper proposes a lattice Boltzmann model with an
amending function for one-dimensional nonlinear partial
differential equations (NPDEs) in the form u_t+α uusub>x+β
u^{n}usub>x+γ usub>xx+δ usub>xxx+ζ usub>xxxx=0. This model is
different from existing models because it lets the time step
be equivalent to the square of the space step and derives higher
accuracy and nonlinear terms in NPDEs. With the Chapman--Enskog
expansion, the governing evolution equation is recovered correctly
from the continuous Boltzmann equation. The numerical results
agree well with the analytical solutions.

A chaotic system is bounded, and its trajectory is confined
to a certain region which is called the chaotic attractor. No matter how
unstable the interior of the system is, the trajectory never
exceeds the chaotic attractor. In the present paper, the sphere
bound of the generalized Lorenz system is given, based on the
Lyapunov function and the Lagrange multiplier method. Furthermore, we
show the actual parameters and perform numerical simulations.

A permanent magnet synchronous motor (PMSM) may have
chaotic behaviours under certain working conditions, especially for
uncertain values of parameters, which threatens the security and
stability of motor-driven operation. Hence, it is important to study
methods of controlling or suppressing chaos in PMSMs. In this paper,
the stability of a PMSM with parameter uncertainties is investigated.
After uncertain matrices which represent the variable system
parameters are formulated through matrix analysis, a novel
asymptotical stability criterion is established by employing the
method of Lyapunov functions and linear matrix inequality
technology. An example is also given to illustrate the
effectiveness of our results.

The problem of reliable impulsive synchronization for a
class of nonlinear chaotic systems has been investigated in this
paper. Firstly a reliable impulsive controller is designed by using
the impulsive control theory. Then by the uniform asymptotic
stability criteria of systems with impulsive effects, some
sufficient conditions for reliable impulsive synchronization between
the drive system and the response system are obtained. Numerical
simulations are given to show the effectiveness of the proposed
method.

In this paper, a novel adaptive control approach is
presented to simultaneously achieve synchronization and
anti-synchronization in partially linear chaotic systems. Through
appropriately separating state vectors of such systems,
synchronization and anti-synchronization could be simultaneously
realized in different subspaces, which may be strictly proven
theoretically. Simulation results for a Lorenz chaotic system and a
new hyper-chaotic system are provided to illustrate the
effectiveness of the proposed method. Finally, a new secure
communication scheme based on such a synchronization phenomenon of
the hyper-chaotic system is demonstrated. Numerical results show
success in transmitting a periodic signal with high security.

The vibrational dynamics of HOCl and HOBr between
bending and OCl/OBr stretching coordinates with anharmonicity and
Fermi coupling is studied with the classical dynamical potential
approach. The quantal vibrational dynamics is mostly mapped out by
the classical nonlinear variables such as fixed points, except for
the state energies, which are quantized. This approach is global in
the sense that the focus is on a set of levels instead of individual
ones. The dynamics of HOBr is demonstrated to be less complicated.
The localized modes along the OCl/OBr stretching coordinates are
also shown to have O--Br bonds more prone to dissociation.

This paper aims to study the stochastic period-doubling
bifurcation of the three-dimensional R?ssler system with an
arch-like bounded random parameter. First, we transform the
stochastic R?ssler system into its equivalent deterministic one
in the sense of minimal residual error by the Chebyshev polynomial
approximation method. Then, we explore the dynamical behaviour of
the stochastic R?ssler system through its equivalent
deterministic system by numerical simulations. The numerical results
show that some stochastic period-doubling bifurcation, akin to the
conventional one in the deterministic case, may also appear in the
stochastic R?ssler system. In addition, we also examine the
influence of the random parameter intensity on bifurcation
phenomena in the stochastic R?ssler system.

The full velocity difference model proposed by Jiang et
al. [2001 Phys. Rev. E 64 017101] has been improved
by introducing velocity anticipation. Velocity anticipation means
the follower estimates the future velocity of the leader. The
stability condition of the new model is obtained by using the linear
stability theory. Theoretical results show that the stability region
increases when we increase the anticipation time interval. The mKdV
equation is derived to describe the kink--antikink soliton wave and
obtain the coexisting stability line. The delay time of car motion
and kinematic wave speed at jam density are obtained in this model.
Numerical simulations exhibit that when we increase the anticipation
time interval enough, the new model could avoid accidents under
urgent braking cases. Also, the traffic jam could be suppressed by
considering the anticipation velocity. All results demonstrate that
this model is an improvement on the full velocity difference model.

In this paper, we attempt to understand complex network
evolution from the underlying evolutionary relationship between
biological organisms. Firstly, we construct a Pfam domain interaction
network for each of the 470 completely sequenced organisms, and
therefore each organism is correlated with a specific Pfam domain
interaction network; secondly, we infer the evolutionary
relationship of these organisms with the nearest neighbour joining
method; thirdly, we use the evolutionary relationship between
organisms constructed in the second step as the evolutionary course
of the Pfam domain interaction network constructed in the first step.
This analysis of the evolutionary course shows: (i) there is
a conserved sub-network structure in network evolution; in this
sub-network, nodes with lower degree prefer to maintain their
connectivity invariant, and hubs tend to maintain their role as a hub
is attached preferentially to new added nodes; (ii) few nodes are
conserved as hubs; most of the other nodes are conserved as one
with very low degree; (iii) in the course of network evolution, new
nodes are added to the network either individually in most cases or
as clusters with relative high clustering coefficients in a very few
cases.

Based on a recent loopless mounting method, a simplified
loopless and bufferless crystal mounting method is developed for
macromolecular crystallography. This simplified crystal mounting
system is composed of the following components: a home-made glass
capillary, a brass seat for holding the glass capillary, a flow
regulator, and a vacuum pump for evacuation. Compared with the
currently prevalent loop mounting method, this simplified method has
almost the same mounting procedure and thus is compatible with the
current automated crystal mounting system. The advantages of this
method include higher signal-to-noise ratio, more accurate
measurement, more rapid flash cooling, less x-ray absorption
and thus less radiation damage to the crystal. This method can be
extended to the flash-freeing of a crystal without or with soaking
it in a lower concentration of cryoprotectant, thus it may be the best
option for data collection in the absence of suitable
cryoprotectant. Therefore, it is suggested that this mounting method
should be further improved and extensively applied to
cryocrystallographic experiments.

We propose a substrate-free focal plane array (FPA) in
this paper. The solid substrate is completely removed, and the
microcantilevers extend from a supporting frame. Using finite
element analysis, the thermal and mechanical characterizations
of the substrate-free FPA are presented. Because of the large
decrease in thermal conductance, the supporting frame is temperature
dependent, which brings out a unique feature: the lower the thermal
conductance of the supporting frame is, the higher the energy
conversion efficiency in the substrate-free FPA will be. The results
from the finite element analyses are consistent with our
measurements: two types of substrate-free FPAs with pixel sizes
of 200× 200 and 60× 60~μ m^{2} are implemented
in the proposed infrared detector. The noise equivalent temperature
difference (NETD) values are experimentally measured to be 520 and
300~mK respectively. Further refinements are considered in various
aspects, and the substrate-free FPA with a pixel size of 30×
30~μ m^{2} has a potential of achieving an NETD value of
10~mK.

The compound diffractive telescope is a novel space optical
system which combines the structure of compound eyes with
diffractive optics and so it has a lighter weight, a wider field of
view (FOV), a lower cost as well as looser fabrication tolerance. In
this paper, the design of a compound diffractive telescope
composed of one primary lens and twenty-one eyepieces is
introduced. Then the influence of diffraction orders on the
performance of the system is analysed. A modified phase function
model of diffractive optics is proposed to analyse the modulation
transfer function (MTF) curves for 0℃ FOV, which provides a
more accurate prediction of the performance of the system. In
addition, an optimized mechanism is also proposed to suppress stray
light. The star image and resolution tests show that the system can
achieve diffraction limit imaging within ± 2℃ of FOV and
±4~mm of eccentricity. Finally, a series of pictures of an object
are taken from different channels, and the splicing of pictures from
adjacent FOVs is demonstrated. In summary, the designed system has
been proved to have great potential applications.

The accelerator-generating 6.13~MeV pulsed Gamma by
^{19}F(p, αγ )^{160} reaction usually synchronizes
with an intense bremsstrahlung x-ray which has a maximum energy of
1~MeV. This paper proposes a new method, named the scattering and
absorbing method, to diagnose the 6.13~MeV Gamma. This method
includes two parts: the detector and a scatterer placed in front of
the detector. The detector converts the Gamma to electrons and then
collects the electrons by a scintillator. In order to restrain the
interference of the low-energy background, the scintillator collects the
electrons at a small angle. The scintillator is wrapped with
electro-absorbing material to absorb the low-energy electrons
generated by background x-rays. The theoretical sensitivity ratio of
6.13~MeV Gamma to 1~MeV x-rays is greater than 150. The scatterer is a
pretreatment tool to scatter some background x-rays away from the
radial beam before they enter the detector. By varying the length,
the scatterer can reduce the background x-rays to an acceptable level for
the detector.

The carburizing of titanium (Ti) is accomplished by utilizing
energetic ion pulses of a 1.5 kJ Mather type dense plasma focus (DPF)
device operated in methane discharge. X-ray diffraction (XRD)
analysis confirms the deposition of polycrystalline titanium carbide
(TiC). The samples carburized at lower axial and angular positions
show an improved texture for a typical (200)TiC plane.
The Williamson--Hall method is employed to estimate average crystallite
size and microstrains in the carburized Ti surface. Crystallite size
is found to vary from ～ 50 to 100~nm, depending on the deposition
parameters. Microstrains vary with the sample position and hence ion
flux, and are converted from tensile to compressive by increasing
the flux. The carburizing of Ti is confirmed by two major doublets
extending from 300 to 390~cm^{-1} and from 560 to 620~cm^{-1} corresponding to acoustic and optical active modes in Raman
spectra, respectively. Analyses by scanning electron
microscopy/energy dispersive x-ray spectroscopy (SEM/EDS) have
provided qualitative and quantitative profiles of the carburized
surface. The Vickers microhardness of Ti is significantly improved after
carburizing.

A detailed first-principles study of the diffusion behaviour of point
defects in the O-terminated (0001) surface in wurtzite ZnO was performed.
The O vacancy and interstitial are found to diffuse much more easily in
surface than in bulk. The Zn vacancy has a similar migration barrier for
both bulk and surface, but has much smaller barrier for the diffuse-in
process. The Zn interstitial is difficult to diffuse in the surface
directly, but it can diffuse into the bulk relatively easily. Specific
values of corresponding migration barriers are obtained.

Absorption spectra of β -carotene in 31 solvents
are measured in ambient conditions. Solvent effects on the 0--0 band
energy, the bandwidth, and the transition moment of the S_{0} →
S_{2} transition are analysed. The discrepancies between published
results of the solvent effects on the 0--0 band energy are
explained by taking into account microscopic solute-solvent
interactions. The contributions of polarity and polarizability of
solvents to 0--0 band energy and bandwidth are quantitatively
distinguished. The 0--0 transition energy of the S_{2} state at the gas
phase is predicted to locate between 23000 and 23600~cm^{-1}.

An interaction potential for an N_{2}(X^{1}σ_{g+}) molecule is constructed by using the highly accurate
valence internally contracted multireference configuration
interaction method and the largest basis set, aug-cc-pV6Z, in the
valence range. The potential is used to investigate the elastic
scattering of two N atoms at energies from 1.0× 10^{-1}1
to 1.0× 10^{-4} a.u. The derived total elastic cross
sections are very large and almost constant at ultralow
temperatures, and the shape of total elastic cross section curve is
mainly dominated by the s-partial wave at very low collision
energies. Three shape resonances are found in the total elastic
cross sections. Concretely, the first one is very sharp and strong.
It results from the g-partial-wave contribution and the resonant
energy is 3.645× 10^{-6} a.u. The second one is contributed
by the h-partial wave and the resonant energy is 1.752× 10^{-5} a.u. This resonance is broadened by those from the d- and
f-partial waves. The third one comes from the l = 6 partial wave
contribution and the resonant energy is 3.522× 10^{-5} a.u.
This resonance is broadened by those from the g- and h-partial
waves. The N_{2}(X^{1}σ_{g+}) molecular
parameters, which are determined at the current theoretical level,
achieve very high accuracy due to the employment of the largest
correlation-consistent basis set in the valence range.

Depth profiled positronium (Ps) annihilation lifetime
spectroscopy (PALS) is an extremely useful probe of the pore
characteristics in nanoporous low-dielectric (low-k) constant thin
films. PALS has also been considered as a potential probe to
investigate diffusion barrier integrity and the structural changes
of porous low-k films during their integration with Cu. Hence, it
is essential to understand the diffusion behaviour of positronium/Cu
atoms in the films. In this work, based on the fact that porous
materials possess characteristics of statistical self-similarity, a
fractal model, the Menger sponge model, has been applied to simulate the
structure of a promising dielectric, porous methylsilsesquioxane
(MSQ) films. The diffusion behaviour of Ps out of the fractal model and
into the surrounding vacuum is studied by means of the diffusion
equation and traditional advective--diffusive theory. Predictive
results from our model show good agreement with measurement data.

This paper stuides numerically the model equation in a one
dimensional defective photonic lattice by modifying the potential
function to a periodic function. It is found that defect modes (DMs)
can be regarded as Bloch modes which are excited from the extended
photonic band-gap structure at Bloch wave-numbers with k_{x} = 0.
The DMs for both positive and negative defects are considered in
this method.

We demonstrate coherent beam combining of two
tiled-aperture single-frequency fibre amplifiers with a total output
power of 29.65~W by using the multi-dithering technique. The two laser
beams are packaged closely by using free-space mirrors side by side
into a tiled-aperture with a near-field fill factor of 62\%.
Active phase control of the amplifier is performed on commercially
available digital lock-in amplifiers. Experimental results show that
the power contained in the main-lobe in closed-loop is 1.72 times greater
than that in open-loop, which is 86\% for the ideal case. The
fringe contrast of the far-field fringe pattern is as high as 80\%
when the system is in closed-loop. The beam quality of the combined beam
is computed to be BQ = 1.48. The whole system in closed-loop performs
well in a long-time observation.

In this paper the relations between two spreads, between
two group delays, and between one spread and one group delay in
fractional Fourier transform (FRFT) domains, are presented and three
theorems on the uncertainty principle in FRFT domains are also
developed. Theorem 1 gives the bounds of two spreads in two FRFT
domains. Theorem 2 shows the uncertainty relation between two group
delays in two FRFT domains. Theorem 3 presents the crossed
uncertainty relation between one group delay and one spread in two
FRFT domains. The novelty of their results lies in connecting the
products of different physical measures and giving their physical
interpretations. The existing uncertainty principle in the FRFT domain
is only a special case of theorem 1, and the conventional
uncertainty principle in time-frequency domains is a special case of
their results. Therefore, three theorems develop the relations of
two spreads in time-frequency domains into the relations between two
spreads, between two group delays, and between one spread and one
group delay in FRFT domains.

A dynamic theoretical model of photochemistry and
hologram formation in holographic photopolymer is established, and
the dynamic development process of holographic gratings in the
photopolymer is discussed with the model. A novel multi-wavelength
visible light sensitive photopolymer for holographic storage is
prepared. The influence of exposure wavelength on holographic
storage characteristics is analysed. By fitting the experimental
data of transmittance and diffraction efficiency to a function of
time with different exposure intensities and wavelengths, the
variations of dynamic parameters of photochemistry and
photopolymerization diffusion are presented.

In this paper, we investigate the effects of the spatial
variation of driving-laser phase in a collective two-atom system on
the intensity--intensity correlations of the resonant fluorescence.
It is shown that the intensity--intensity correlations exhibit quite
different characteristics for the different values of the spatial
phase of the laser at the position of the two atoms in both cases of
the weak and strong driving lasers. Our results suggest that the
intensity--intensity correlations can serve as a probe of the spatial
interference effect arising from the spatial variation of the laser
phase.

The entropy squeezing of an atom with a k-photon in the
Jaynes--Cummings model is investigated. For comparison, we also
study the corresponding variance squeezing and atomic inversion.
Analytical results show that entropy squeezing is preferable
to variance squeezing for zero atomic inversion. Moreover, for
initial conditions of the system the relation between squeezing and
photon transition number is also discussed. This provides a
theoretical approach to finding out the optimal entropy squeezing.

Based on the Einstein, Podolsky, and Rosen (EPR) entangled
state representation, this paper introduces the wave function for
the squeezed atomic coherent state (SACS), which turns out to be
just proportional to a single-variable ordinary Hermite polynomial
of order 2j. As important applications of the wave function,
the Wigner function of the SACS and its marginal distribution are
obtained and the eigenproblems of some Hamiltonians for the
generalized angular momentum system are solved.

Based on the rotation transformation in phase space and
the technique of integration within an ordered product of operators,
the coherent state representation of the multimode phase shifting
operator and one of its new applications in quantum mechanics are
given. It is proved that the coherent state is a natural language
for describing the phase shifting operator or multimode phase
shifting operator. The multimode phase shifting operator is also
a useful tool to solve the dynamic problems of the multimode
coordinate--momentum coupled harmonic oscillators. The exact energy
spectra and eigenstates of such multimode coupled harmonic
oscillators can be easily obtained by using the multimode phase
shifting operator.

The emission spectrum of a two-level atom interacting
dispersively with a single mode radiation field in the dissipative
cavity is investigated. A general expression for the emission
spectrum is derived. The numerical results for the initial field in
coherent state are calculated. It is found that the spectrum
structure is influenced significantly by the cavity damping constant
\kappa , and the spectrum structure is dependent on the
interaction time T when the cavity dissipation is present. Only
one peak located at Ω_{a} appears in the atomic spectra for
larger T.

The effects of an applied low frequency field on the
dynamics of a two-level atom interacting with a single-mode field
are investigated. It is shown that the time evolution of the atomic
population is mainly controlled by the coupling constants and the
frequency of the low frequency field, which leads to a low frequency
modulation function for the time evolution of the upper state
population. The amplitude of the modulation function becomes larger
as the coupling constants increase. The frequency of the modulation
function is proportional to the frequency of the low frequency
field, and decreases with increasing coupling constant.

In this paper we have investigated three external fields
interacting with the four-level Y-type atomic system described by
the density-matrix approach. The results show that
left-handedness with zero absorption is achieved. The zero
absorption property displays the possibility of manipulation by
varying the phase and the intensity of the coupling field. Also, the
zero absorption property may be used to amplify the evanescent waves
that have been lost in imaging by traditional lenses. We propose
an approach to obtain a negative refractive medium with zero
absorption and the possibility of enhanceingthe imaging resolution in
realizing `superlenses'.

The filtering mechanism of a free output coupler
mode-locked laser based on large-mode-area photonic-crystal fibre is
analysed. A filtering-soliton mode-locked laser with 495~fs pulse
width and 21 nJ pulse energy is achieved. Another novel cavity
configuration is established to eliminate the filtering effect.
Pulses, each 457~fs in width and 16.5 nJ in energy, are
obtained in a soliton-like regime. Pulses, each 387~fs in
width and 15.8 nJ in energy, are also generated in a stretched pulse
regime and could be dechirped to 119~fs externally to the cavity.

It is important to determine quantitatively the internal
carrier loss arising from heating and barrier height variation in a
vertical-cavity surface-emitting quantum well laser (VCSEL).
However, it is generally difficult to realize this goal using
purely theoretical formulas due to difficulty in deriving the
parameters relating to the quantum well structure. In this paper, we
describe an efficient approach to characterizing and calculating the
carrier loss due to the heating and the barrier height change in the
VCSEL. In the method, the thermal carrier loss mechanism is combined
with gain measurement and calculation. The carrier loss is
re-characterized in a calculable form by constructing the threshold
current and gain detuning-related loss current using the measured
gain data and then substituting them for the quantum well-related
parameters in the formula. The result can be expressed as a product
of an exponential weight factor linked to the barrier height change
and the difference between the threshold current and gain
detuning-related loss current. The gain variation at cavity
frequency due to thermal carrier loss and gain detuning processes is
measured by using an AlInGaAs--AlGaAs VCSEL structure. This work
provides a useful approach to analysing threshold and loss
properties of the VCSEL, particularly, gain offset design for high
temperature operation of VCSELs.

A theory of a two-stream free-electron laser in a combined
electromagnetic wiggler (EMW) is developed, in which we use an
axial-guide magnetic field and take into account the effects of the
self-fields. The electron trajectories and the small signal gain are
derived. The stability of the trajectories, the characteristics of
the linear-gain, and the normalised maximum gain are studied
numerically. The results show that there are nine stable groups of
orbits in the presence of self-fields instead of seven groups
reported in the absence of the self-field. It is also shown that
the normalised gains of four groups of the orbits are decreasing and
those for the rest of them are increasing with growing \barΩ_{0}. Furthermore, it is found that the two-stream
laser with self-field enhances the maximum gain in comparison with
the single stream case.

A Kerr-lens mode-locked Ti:sapphire laser operating in a
non-soliton regime is demonstrated. Dispersive wave generation is
observed as a result of third order dispersion in the vicinity of
zero dispersion. The characteristics of the Ti:sapphire laser
operating in a positive dispersion regime are presented, where the
oscillator directly generates pulses with duration continuously
tunable from 0.37~ps to 2.11~ps, and 36~fs pulses are achieved after
extracavity compression. The oscillation is numerically simulated
with an extended nonlinear Schr?dinger equation, and the
simulation results are in good agreement with the experimental
results.

A novel relative rotation sensor based on slow light is
proposed and analysed. A theoretical analysis shows that the high
sensitivity of the proposed rotation sensor is achieved through an
electromagnetically-induced-transparency medium. Unlike the
tradition detection method, the idea of rotation sensing is to
detect group delay between counterpropagating wave packets.
It can be used to realize an ultra-precise rotation sensor.

Nonsymmetrical transition from reverse-saturable
absorption (RSA) to saturable absorption (SA) caused by excited
state absorption induced mass transport of the CuPcTs dissolved in
dimethyl sulfoxide is observed in an open aperture Z-scan experiment
with a 21-ps laser pulse. The nonsymmetrical transition from RSA to SA
is ascribed neither to saturation of excited state absorption nor to
thermal induced mass transport, the so-called Soret effect. In our
consideration, strong nonlinear absorption causes the rapid
accumulation of the non-uniform kinetic energy of the solute
molecules. The non-uniform kinetic field in turn causes the
migration of the solute molecules. Additionally, an
energy-gradient-induced mass transport theory is presented to
interpret the experimental results, and the theoretical calculations
are also taken to fit our experimental results.

2D and 3D submicron periodic structures are first
fabricated by red-induced photopolymerization using a common 635~nm
semiconductor laser and specially developed red-sensitive polymer
material. The principle of this new photo-polymer material
fabrication is explained and the absorption spectra of the material
are measured. This fabrication technique allows a deeper penetration
into volume and larger interference irradiation area which is more
than 1~cm^{2}. The optical design, theoretical calculations
and experimental results including diffraction patterns
verifying the formation of periodic structures are presented.
Compared with other fabrication technologies using high-power
lasers, this approach has greatly reduced the demand for laser
apparatus. Therefore, it is much more accessible to most
laboratories and potentially usable in holographic fabrication of
photonic crystals and devices in micro electro-mechanical
systems (MEMS).

A high efficiency and broad bandwidth grating coupler
between a silicon-on-insulator (SOI) nanophotonic waveguide and fibre
is designed and fabricated. Coupling efficiencies of 46\% and
25\% at a wavelength of 1.55~μ m are achieved by simulation
and experiment, respectively. An optical 3~dB bandwidth of 45~nm
from 1530~nm to 1575~nm is also obtained in experiment. Numerical
calculation shows that a tolerance to fabrication error of 10~nm
in etch depth is achievable. The measurement results indicate that
the alignment error of ±2~μ m results in less than 1~dB
additional coupling loss.

In this work, we investigate strain effects induced by the
deposition of gate dielectrics on the valence band structures in Si
(110) nanowire via the simulation of strain distribution and the
calculation of a generalized 6× 6k.p strained
valence band. The nanowire is surrounded by the gate dielectric. Our
simulation indicates that the strain of the amorphous SiO_{2}
insulator is negligible without considering temperature factors. On
the other hand, the thermal residual strain in a nanowire with
amorphous SiO_{2} insulator which has negligible lattice misfit
strain pushes the valence subbands upwards by chemical vapour
deposition and downwards by thermal oxidation treatment. In contrast
with the strain of the amorphous SiO_{2} insulator, the strain of
the HfO_{2} gate insulator in Si (110) nanowire pushes the valence
subbands upwards remarkably. The thermal residual strain by
HfO_{2} insulator contributes to the up-shifting tendency. Our
simulation results for valence band shifting and warping in Si
nanowires can provide useful guidance for further nanowire device
design.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

Taking into account both the intrinsic curvature and
Zeeman effects, persistent currents in a multi-walled carbon nanotorus
are explored by using a supercell method, within the tight-binding
formalism. It is shown that in the absence of the Zeeman effect, the
intrinsic curvature induces some dramatic changes in energy spectra
and thus changes in the shape of the flux-dependent current. A
paramagnetism--diamagnetism transition is observed. With consideration of
the Zeeman splitting energy, the period of persistent current is
destroyed, and a diamagnetism--paramagnetism transition is obtained
at high magnetic field. In addition, we further explore the effect
of external electric field energy (E_{ef}) on persistent
current, indicating that it changes unmonotonously with E_{ef}.

The interaction between an edge dislocation and a crack
emanating from a semi-elliptic hole is dealt with. Utilizing the
complex variable method, closed form solutions are derived for
complex potentials and stress fields. The stress intensity factor at
the tip of the crack and the image force acting on the edge
dislocation are also calculated. The influence of the morphology of
the blunt crack and the position of the edge dislocation on the
shielding effect to the crack and the image force is examined in
detail. The results indicate that the shielding or anti-shielding
effect to the stress intensity factor increases acutely when the
dislocation approaches the tip of the crack. The effect of the
morphology of the blunt crack on the stress intensity factor of the
crack and the image force is very significant.

We investigate the microstructures of the pure aluminium foil
and filter used on the space solar telescope, irradiated by photons
with different doses. The vacancy defect clusters induced by proton
irradiation in both samples are characterized by transmission
electron microscopy, and the density and the size distribution of
vacancy defect clusters are determined. Their transmittances are
measured before and after irradiating the samples by protons
with energy E=100~keV and dose φ =6× 10^{11}/mm^{2}.
Our experimental results show that the density and the size of
vacancy defect clusters increase with the increase of irradiation
doses in the irradiated pure aluminium foils. As irradiation dose
increases, vacancies incline to form larger defect clusters. In the
irradiated filter, a large number of banded void defects are
observed at the agglomerate boundary, which results in the
degradation of the optical and mechanical performances of the
filter after proton irradiation.

Using first-principles calculations, this paper
systematically investigates the structural, elastic, and electronic
properties of ReN_{4}. The calculated positive eigenvalues of the
elastic constant matrix show that the orthorhombic Pbca structure
of ReN_{4} is elastically stable. The calculated band structure
indicates that ReN_{4} is metallic. Compared with the synthesized
superhard material WB_{4}, it finds that ReN_{4} exhibits larger
bulk and shear moduli as well as a smaller Poisson's ratio. In
addition, the elastic constant c_44 of ReN_{4} is larger than
all the known 5d transition metal nitrides and borides. This
combination of properties makes it an ideal candidate for a superhard
material.

The phonon dispersion relations of three kinds of 4~?
carbon nanotubes are calculated by using the density functional
perturbation theory. It is found that the frequencies of some phonon
modes are very sensitive to the smearing width used in the
calculations, and eventually become negative at low electronic
temperature. Moreover, two kinds of soft modes are identified for
the (5,0) tube which are quite different from those reported
previously. Our results suggest that the (5,0) tube remains metallic
at very low temperature, instead of the metallic-semiconducting
transition claimed before.

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

This paper describes the accepted meaning of the term`negative resistance' and its use in the literature, and discusses
the features in the previously published data on QTC^{TM} (market name of a metal--polymer composite) that show that the non-linear, hysteretic current voltage characteristics are not caused by Joule heating. The benefit of the high metal filler loading in QTC^{TM} and other unique features of this composite are reviewed.

The effects of La and Sb doping on the electronic structure and optical properties of SrTiO_{3} are investigated by first-principles calculation of the plane wave ultra-soft pseudo-potential based on density functional theory. The calculated results reveal that corner-shared TiO_{6} octahedra dominate the main electronic properties of SrTiO_{3}, and its structural stability can be improved by La doping. The La^{3+} ion fully acts as an electron donor in Sr_{0.875}La_{0.125}TiO_{3} and the Fermi level shifts into the conduction bands (CBs) after La doping. As for SrSb_{0.125}Ti_{0.875}O_{3}, there is a distortion near the bottom of the CBs for SrSb_{0.125}Ti_{0.875}O_{3} after Sb doping and an incipient localization of some of the doped electrons trapped in the Ti site, making it impossible to describe the evolution of the density of states (DOS) within the rigid band model. At the same time, the DOSs of the two electron-doped systems shift towards low energies and the optical band gaps are broadened by about 0.4 and 0.6 eV for Sr_0.875La_0.125TiO_{3} and
SrSb_{0.125}Ti_{0.875}O_{3}, respectively. Moreover, the
transmittance of SrSb_{0.125}Ti_{0.875}O_{3} is as high as
95\% in most of the visible region, which is higher than that of
Sr_{0.875}La_{0.125}TiO_3 (85\%). The wide band gap, the
small transition probability and the weak absorption due to the low
partial density of states (PDOS) of impurity in the Fermi level
result in the significant optical transparency of
SrSb_0.125Ti_0.875O_{3}.

The low temperature specific heat of Sm-Al-Co ternary
metallic glasses is investigated and a clear anomaly associated with
the Boson peak is identified. While this anomaly depends slightly on
the chemical composition, it has no dependence on external magnetic
field. To figure out the mechanism of the Boson peak, we interpret
the data within various model frameworks. Unlike earlier
work, our study shows that this Boson peak is mainly ascribed to an
additional T^{2} term of the specific heat, which may originate
from the quasi-two-dimensional and short-range ordered structure
units possibly existing in the metallic glasses.

Conductances of different geometric conformations of boron
ribbon devices are calculated by the ab initio method.
The I--V characteristics of three devices are rather different due
to the difference in structure. The current of the hexagonal boron
device is the largest and increases nonlinearly. The current of the
hybrid hexagon-triangle boron device displays a large low-bias
current and saturates at a value of about 5.2~μ A. The current
of the flat triangular boron flake exhibits a voltage gap at low bias
and rises sharply with increasing voltage. The flat triangular boron
device can be either conducting or insulating, depending on the
field.

Cubic boron nitride thin films were deposited on silicon
substrates by low-pressure inductively coupled plasma-enhanced
chemical vapour deposition. It was found that the introduction of
O_{2} into the deposition system suppresses both nucleation and
growth of cubic boron nitride. At a B_{2}H_{6} concentration of
2.5\% during film deposition, the critical O_{2} concentration
allowed for the nucleation of cubic boron nitride was found to be
less than 1.4\%, while that for the growth of cubic boron nitride
was higher than 2.1\%. Moreover, the infrared absorption peak
observed at around 1230--1280~cm^{-1}, frequently detected for
cubic boron nitride films prepared using non-ultrahigh vacuum
systems, appears to be due to the absorption of boron oxide, a
contaminant formed as a result of the oxygen impurity. Therefore,
the existence of trace oxygen contamination in boron nitride films
can be evaluated qualitatively by this infrared absorption peak.

Ion-implantation layers are fabricated by multiple
nitrogen ion-implantations (3 times for sample A and 4 times for
sample B) into a p-type 4H-SiC epitaxial layer. The implantation depth
profiles are calculated by using the Monte Carlo simulator TRIM. The
fabrication process and the I--V and C--V characteristics
of the lateral Ti/4H-SiC Schottky barrier diodes (SBDs) fabricated
on these multiple box-like ion-implantation layers are presented in
detail. Measurements of the reverse I--V characteristics
demonstrate a low reverse current, which is good enough for many
SiC-based devices such as SiC metal--semiconductor field-effect
transistors (MESFETs), and SiC static induction transistors (SITs).
The parameters of the diodes are extracted from the forward I--V
and C--V characteristics. The values of ideality factor n of
SBDs for samples A and B are 3.0 and 3.5 respectively, and the
values of series resistance R_\rm s are 11.9 and 1.0~kΩ
respectively. The values of barrier height φ _\rm B of
Ti/4H-SiC are 0.95 and 0.72 eV obtained by the I--V method and 1.14
and 0.93 eV obtained by the C--V method for samples A and B
respectively. The activation rates for the implanted nitrogen ions
of samples A and B are 2\% and 4\% respectively extracted from
C--V testing results.

The ohmic contacts of 4H-SiC are fabricated on nitrogen ion implanted layers made by performing
box-like-profile implantation three and four times. Implantation parameters such as the standard deviation σ and the projection range R_{p} are calculated by the Monte Carlo simulator TRIM. Ni/Cr ohmic contacts on Si-face 4H-SiC implantation layers are measured by transfer length methods (TLMs). The results show that the values of sheet resistance R_{sh} are 30~kΩ /□ and 4.9~kΩ/□ and the values of specific contact resistance ρ_{c} of ohmic contacts are 7.1× 10^{-4}Ω.cm^{2} and 9.5× 10^{-5}Ω.cm^{2} for the implanted layers with
implantation performed three and four times respectively.

The interaction of Ag atoms with a defective MgO(001)
surface is systematically studied based on density functional
theory. The Ag clusters are deposited on neutral and charged oxygen
vacancies of the MgO(001) surface. The structures of Ag clusters
take the shape of simple models of two- or three-dimensional (2D and
3D) metal particles deposited on the MgO surface. When the nucleation of
the metal clusters occurs in the F_{s} (missing neutral O)
centre, the interaction with the substrate is considerably stronger
than that in the F_{s+} (missing O^{-} ) centre. The
results show that the adsorption of Ag atoms on the MgO surface with
oxygen vacancy is stronger than on a clear MgO surface, thereby
attracting more Ag atoms to cluster together, and forming atomic
islands.

In this paper, two kinds of modified surface plasmonic
waveguides formed by nanometric parallel lines are proposed. The
finite-difference frequency-domain method is used to study
propagation properties of the fundamental mode supported by these
surface plasmonic waveguide structures. Results show that the
transverse magnetic field of the fundamental mode is mainly
distributed in the face to face region formed by two rods. With the
same geometrical parameters and the same working wavelength of
632.8~nm, in the case of rods with a triangular cross-section, the
degree of localization of field is strong, i.e. the mode area is
small, but the fraction of the modal power in the metal increases,
so the effective index increases and the propagation length of the
mode decreases. With the same geometrical parameters, relative to
the case of a working wavelength of 632.8~nm, when working wavelength
is large, the mode area of transverse magnetic field distribution is
large, i.e. the degree of localization of field is weak, and the
interaction of field and silver is weak too, then the effective
index decreases, so the propagation length increases. The rounded
radii of rods have a great influence on the performance of the surface
plasmonic waveguides with rounded triangular cross-sections, but have
little influence on the performance of surface plasmonic waveguides
with rounded square cross-sections. Since the distribution of
transverse magnetic field, effective index, propagation length and
the mode area can be adjusted by the geometrical parameters, this
kind of modified surface plasmonic waveguide can be applied to the
field of photonic device integration and sensors.

We investigate the transmission properties of a normally
incident TM plane wave through metal films with periodic
parabolic-shaped grooves on single and double surfaces using the
finite-difference-time-domain method. Nearly zero transmission
efficiency is found at wavelengths corresponding to surface plasmon
excitation on a flat surface in the case where the single surface is
grooved. Meanwhile, resonant excitation of surface plasmon polariton
(SPP) Bloch modes leads to a strong transmission peak at slightly
larger wavelengths. When the grating is grooved on double surfaces,
the transmission enhancement can be dramatically improved due to the
resonant tunnelling between SPP Bloch modes.

Nanocomposites of
poly[(2-methoxy,5-octoxy)1,4-phenylenevinylene]-zinc selenide
(MOPPV-ZnSe) are synthesized by mixing the polymerization of 1,4-bis
(chloromethyl)-2-methoxy-5-octoxy-benzene in the presence of ZnSe
quantum dots. The resulting MOPPV-ZnSe nanocomposites possess a
well-defined interfacial contact, thus significantly promoting the
dispersion of ZnSe within the MOPPV matrix and facilitating the
electronic interaction between these two components. Raman and
UV--visible absorption spectra are influenced by the incorporation
of ZnSe nanocrystals. High-resolution transmission electron
microscopic and tapping-mode atomic force microscopic results show
clearly the evidence for phase-segregated networks of ZnSe
nanocrystals, which provide a large area of interface for charge
separation to occur. Steady-state spectra of MOPPV-ZnSe
nanocomposites are markedly quenched by the introduction of intimate
polymer/ZnSe junctions. Time-resolved photoluminescence
measurements show that the lifetime decays quickly, which further
confirms the occurrence of charge transfer in MOPPV-ZnSe
nanocomposites.

Phase field investigation reveals that the stability of
the planar interface is related to the anisotropic intensity of
surface tension and the misorientation of preferred crystallographic
orientation with respect to the heat flow direction. The large
anisotropic intensity may compete to determine the stability of the
planar interface. The destabilizing effect or the stabilizing effect
depends on the misorientation. Moreover, the interface morphology of
initial instability is also affected by the surface tension
anisotropy.

SiN_x is commonly used as a passivation material for
AlGaN/GaN high electron mobility transistors (HEMTs). In this paper,
the effects of SiN_x passivation film on both two-dimensional
electron gas characteristics and current collapse of AlGaN/GaN HEMTs
are investigated. The SiN_x films are deposited by high- and
low-frequency plasma-enhanced chemical vapour deposition, and they
display different strains on the AlGaN/GaN heterostructure, which
can explain the experiment results.

To form low-resistance Ohmic contact to p-type GaN,
InGaN/GaN multiple quantum well light emitting diode wafers are
treated with boiled aqua regia prior to Ni/Au (5~nm/5~nm) film
deposition. The surface morphology of wafers and the current--voltage
characteristics of fabricated light emitting diode devices are
investigated. It is shown that surface treatment with boiled
aqua regia could effectively remove oxide from the surface of the p-GaN
layer, and reveal defect-pits whose density is almost the same as
the screw dislocation density estimated by x-ray rocking curve
measurement. It suggests that the metal atoms of the Ni/Au transparent
electrode of light emitting diode devices may diffuse into the p-GaN
layer along threading dislocation lines and form additional leakage
current channels. Therefore, the surface treatment time with boiled
aqua regia should not be too long so as to avoid the increase of
threading dislocation-induced leakage current and the degradation of
electrical properties of light emitting diodes.

The influence of orientation on electromagnetic properties
of basalt fibre/nickel core--shell heterostructures prepared by a
simple electroless plating method is investigated. For comparison,
the same investigation is also performed on naked basalt fibres.
For electromagnetic measurement, the directions of basalt
fibre/nickel and naked basalt fibres are parallel, random and
perpendicular to the direction of external electric field, termed
E_\vert\vert sample, random sample and E_{⊥} sample,
respectively. Electromagnetic anisotropy can be clearly observed in
the basalt fibre/nickel core--shell heterostructures, while
electromagnetic properties of naked basalt fibres are unrelated to
the orientation. The E_{⊥} basalt fibre/nickel shows the
highest dielectric loss but the lowest magnetic loss, and E_{||} basalt fibre/nickel exhibits the highest magnetic loss but the lowest dielectric loss. The dielectric loss of E_{⊥}
basalt fibre/nickel is several times as large as that of E_{||} basalt fibre/nickel, which could be attributed to the increase of polarization relaxation time as a consequence of the
nanosize-confinement effect. The magnetic loss of E_{||}
basalt fibre/nickel is even one order of magnitude higher than that
of E_{⊥} basalt fibre/nickel, which originates mainly from
the natural magnetic resonance of basalt fibre/nickel core--shell
heterostructures.

This paper reports that single-phase γ
-Y_{2}Si_{2}O_{7} is prepared via a sufficient blending
and cold-pressed sintering technique from Y_{2}O_{3} powder and
SiO_{2} nanopowder. It studies the dielectric properties of
γ -Y_{2}Si_{2}O_{7} as a function of the
temperature and frequency. The γ -Y_{2}Si_{2}O_{7}
exhibits low dielectric loss and non-Debye relaxation behaviour from
25 to 1400~℃C in the range of 7.3--18~GHz. The mechanism for
polarization relaxation of the as-prepared γ
-Y_{2}Si_{2}O_{7} differing from that of SiO_{2} is
explained. Such particular dielectric properties could potentially
make specific attraction for extensive practical applications.

This paper reports that a novel yellow phosphor, LiSrBO_{3}:Eusup>2+, was
synthesized by the solid-state reaction. The excitation and emission
spectra indicate that this phosphor can be effectively excited by
ultraviolet (360 and 400~nm) and blue (425 and 460~nm) light, and
exhibits a satisfactory yellow performance (565~nm). The role of
concentration of Eusup>2+ on the emission intensity in
LiSrBO_{3} is studied, and it is found that the critical
concentration is 3 mol\%, and the concentration self-quenching
mechanism is the dipole--dipole interaction according to the Dexter theory.
White light emitting diodes were generated by using an InGaN chip
(460~nm or 400~nm) with LiSrBO_{3}:Eusup>2+ phosphor, the CIE
chromaticity is (x=0.341, y=0.321) and (x=0.324, y=0.318),
respectively. Therefore, LiSrBO_{3}:Eusup>2+ is a promising
yellow phosphor for white light emitting diodes.

8000 CROSSDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY

The scaling of the flowfield in a gas--gas combustion
chamber is investigated theoretically, numerically and
experimentally. To obtain the scaling criterion of the gas--gas
combustion flowfield, formulation analysis of the three-dimensional
(3D) Navier--Stokes equations for a gaseous multi-component mixing
reaction flow is conducted and dimensional analysis on the gas--gas
combustion phenomena is also carried out. The criterion implies that
the size and the pressure of the gas--gas combustion chamber can be
changed. Based on the criterion, multi-element injector chambers
with different geometric sizes and at different chamber pressures
ranging from 3~MPa to 20~MPa are numerically simulated. A
multi-element injector chamber is designed and hot-fire tested at
five chamber pressures from 1.64~MPa to 3.68~MPa. Wall temperature
measurements are used to understand the similarity of combustion
flowfields in the tests. The results have verified the similarities
between combustion flowfields under different chamber pressures and
geometries, with the criterion applied.

We propose a scheme to generate isolated attosecond pulses
in the water-window spectral region. Based on the numerical solutions of
the single active electron model, we investigate high-order harmonic
generation in helium atoms driven by a multi-cycle two-colour
optical field synthesized by an intense 2000 nm, 20 fs pulse and its
frequency-doubled pulse. When the latter is slightly detuned and
properly phase shifted with respect to the fundamental laser pulse,
an ultra-broad extreme ultraviolet supercontinuum with a spectral
width of 130~eV can be generated in the 270--400~eV spectral regions.
A supercontinuum from 280--340~eV in the water window can be
selected to yield an isolated 67 attosecond pulse without employing
any phase compensation. This water window coherent x-ray pulse with
less than 100 attosecond duration is a potential tool for studying
the ultrafast electronic dynamics of biological samples in water.

In this paper, the properties of dark energy are
investigated according to the parameterized deceleration parameter
q(z), which is used to describe the extent of the accelerating
expansion of the universe. The potential of dark energy V(φ)
and the cosmological parameters, such as the dimensionless energy
density \varOmega_φ, \varOmega_m, and the state parameter
w_φ, are connected to it. Concretely, by giving two kinds of
parameterized deceleration parameters q(z)=a+bz/(1+z) and
q(z)=1/2+(az+b)/(1+z)^2, the evolution of these parameters
and the reconstructed potentials V(φ) are plotted and analysed.
It is found that the potentials run away with the evolution of
universe.

Combining the general relativity and the uncertainty
relation in quantum mechanics, the energy density of quantum
fluctuations of space-time can be viewed as dark energy. The
so-called agegraphic dark energy model is just based on this
viewpoint, in which the age of the universe is introduced as the
length measure. Recently, the new agegraphic dark energy model was
proposed, where the dynamical dark energy is measured by the
conformal age of the universe. On the other hand, scalar-field dark
energy models like tachyons are often regarded as an effective
description of some underlying theory of dark energy. In this paper,
we show that the new agegraphic dark energy can be described
completely by a tachyon scalar-field. We thus reconstruct the
potential and the dynamics of the tachyon scalar-field, according to
the evolution of the new agegraphic dark energy.

According to recent investigations of states of quantum fields, we
postulate that there exist negative energy photons in the universe.
With this assumption, we find a solution of Einstein's equation
without introducing the cosmological constant. A new and sizable
type Ia supernovae sample is employed to perform a fit with our
model and the conventional model. Both models can well account for
the current type Ia supernovae observation and they are not
distinguishable. With the new model, the cause of the accelerated
expansion of the universe and the mechanism of the negative pressure
existing in outer space can be explained in ordinary physical terms.

[an error occurred while processing this directive]