The stability of second-order differential equations is studied by using
their integrals. A system of second-order differential equations can be
considered as a mechanical system with holonomic constraints. A conserved
quantity of the mechanical system or a part of the system is obtained by
using the Noether theory. It is possible that the conserved quantity becomes
a Liapunov function and the stability of the system is proved by the
Liapunov theorem.

In this paper a submerged horseshoe vortex under a free surface is discussed
and the algebraic expression of the wave elevation is obtained. From this
expression, some characteristics of the ship wave are described. There
exists a smooth region near $\theta = 0^\circ$, but when the uniform stream
passes the other singularities (source, sink, doublet, etc.) there is no
smooth region. The mechanism of synthetic aperture radar (SAR) images of the
narrow ship wakes is also explained.

In this paper,
based on hyperbolic tanh-function method and homogeneous balance
method, and auxiliary equation method, some new exact solitary
solutions to the generalized mKdV equation and generalized
Zakharov--Kuzentsov equation are constructed by the method of
auxiliary equation with function transformation with aid of
symbolic computation system Mathematica. The method is of important
significance in seeking new exact solutions to the evolution
equation with arbitrary nonlinear term.

The ring dark solitons and their head-on collisions in a
Bose--Einstein condensates with thin disc-shaped potential
are studied. It is shown that the system admits a solution with
two concentric ring solitons, one moving inwards and the other
moving outwards, which in small-amplitude limit, are described by
the two cylindrical KdV equations in the respective reference
frames. By using the extended Poincar\'e--Lighthill--Kuo
perturbation method, the analytical phase shifts following
the head-on collisions between two ring dark solitary waves are
derived. It is shown that the phase shifts decrease with the
radial coordinate $r$ according to the $r^{-1/3}$ law and depend
on the initial soliton amplitude and radius.

In this paper, we present the electromagnetic analysis of a rectangular
cavity partially filled with a left-handed material slab. Our
theoretical investigation shows that there exist novel resonant modes
in the cavity, and such a cavity becomes a subwavelength cavity. The eigenvalue equation of the
cavity is derived and the resonant frequencies of the novel modes
are calculated by using numerical simulation. We also discuss the
stability of the novel resonant modes and show the best condition
under which
a useful rectangular cavity of subwavelength dimensions with
tolerable stability is obtained.

Based on the exact solution of the time-dependent Schr\"{o}dinger
equation for two-species Bose--Einstein condensates (BECs)
consisting of two hyperfine states of the atoms coupled by a tuned
adiabatic and time-varying Raman coupling, we obtain analytically
the entanglement dynamics of the system with various initial
states, particularly the SU(2) coherent state, for both of
cases with and without the nonlinear interactions. It is shown
that the effect of nonlinear interaction on the entanglement
appears only in a longer time period depending on the BEC
parameters.

The analytical transfer matrix method (ATMM) is applied to
calculating the critical radius $r_{\rm c}$ and the dipole
polarizability $\alpha_{\rm d}$ in two confined systems: the hydrogen
atom and the Hulth\'{e}n potential. We find that there exists a
linear relation between $r_{\rm c}^{1/2}$ and the quantum number $n_{r}$
for a fixed angular quantum number $l$, moreover, the three bounds
of $\alpha_{\rm d}$ ($\alpha_{\rm d}^{K}$, $\alpha_{\rm d}^{B}$,
$\alpha_{\rm d}^{U}$) satisfy an inequality:
$\alpha_{\rm d}^{K}\leq\alpha_{\rm d}^{B}\leq\alpha_{\rm d}^{U}$. A comparison
between the ATMM, the exact numerical analysis, and the variational
wavefunctions shows that our method works very well in the systems.

We propose a method to probabilistically implement a nonlocal operation, $%
\exp {[}\i\xi U_{A}U_{B}{]}$, between two distant qutrits $A$ and $B$, where $%
\xi \in [0,2\pi ]$ and $U_{A}$, $U_{B}$ are local unitary and Hermitian
operations for qutrits $A$ and $B$ respectively. The consumptions of
resource for one performance of the method are a single non-maximally
entangled qutrit state and 1-trit classical communication. For a given $\xi $%
, the successful probability of the method depends on the forms of both
entanglement resource and Bob's partial-measurement basis. We systematically
discuss the optimal successful probabilities and their corresponding
conditions for three cases: adjustable entanglement resource, adjustable
partial-measurement basis, adjustable entanglement resource and
partial-measurement basis. It is straightforward to generalize the method
for producing nonlocal unitary operations between any two $N$-level systems.

The entropy density, energy density, pressure and equation
of state around the RNAdS black hole are calculated in the WKB
approximation on the Teukolsky-type master equation. The
appearance of spin-dependent terms is demonstrated. The existence
of these terms shows that the black hole radiation is not exactly
thermal radiation and the black hole entropy is not strictly proportional to
the area of the event horizon.

A finite-time controller is designed for a class of nonlinear systems
subject to sector nonlinear inputs. A novel and simple approach is suggested
based on the finite-time control principle. The designed sliding-mode
controller
can drive a chaotic system to track a smooth target signal in a
finite time.
The chaotic Duffing--Holmes oscillator is used for verification and
demonstration.

Support vector machines (SVM) have been widely used in chaotic time series
predictions in recent years. In order to enhance the prediction efficiency
of this method and implement it in hardware, the sigmoid kernel in SVM is
drawn in a more natural way by using the fuzzy logic method proposed in this
paper. This method provides easy hardware implementation and straightforward
interpretability. Experiments on two typical chaotic time series predictions
have been carried out and the obtained results show that the average CPU
time can be reduced significantly at the cost of a small decrease in
prediction accuracy, which is favourable for the hardware implementation for
chaotic time series prediction.

In this paper, the fractional-order Genesio--Tesi system showing chaotic
behaviours is introduced, and the corresponding one in an integer-order form
is studied intensively. Based on the harmonic balance principle, which is
widely used in the frequency analysis of nonlinear control systems, a
theoretical approach is used to investigate the conditions of system
parameters under which this fractional-order system can give rise to a
chaotic attractor. Finally, the numerical simulation is used to verify the
validity of the theoretical results.

In this paper, we propose a multidimensional version of recurrent least
squares support vector machines (MDRLS-SVM) to solve the problem about the
prediction of chaotic system. To acquire better prediction performance, the
high-dimensional space, which provides more information on the system than
the scalar time series, is first reconstructed utilizing Takens's embedding
theorem. Then the MDRLS-SVM instead of traditional RLS-SVM is used in the
high-dimensional space, and the prediction performance can be improved from
the point of view of reconstructed embedding phase space. In addition, the
MDRLS-SVM algorithm is analysed in the context of noise, and we also find
that the MDRLS-SVM has lower sensitivity to noise than the RLS-SVM.

This paper reports a new four-dimensional hyperchaotic system obtained by
adding a controller to a three-dimensional autonomous chaotic system. The
new system has two parameters, and each equation of the system has one
quadratic cross-product term. Some basic properties of the new system are
analysed. The different dynamic behaviours of the new system are studied when
the system parameter $a$ or $b$ is varied. The system is hyperchaotic in
several different regions of the parameter $b$. Especially, the two positive
Lyapunov exponents are both larger, and the hyperchaotic region is also
larger when this system is hyperchaotic in the case of varying $a$. The
hyperchaotic system is analysed by Lyapunov-exponents spectrum, bifurcation
diagrams and Poincar\'{e} sections.

The K-V beam through an axisymmetric uniform-focusing channel is studied
using the particle--core model. The beam halo-chaos is found, and a sample
function controller is proposed based on mechanism of halo formation and
strategy of controlling halo-chaos. We perform multiparticle simulation to
control the halo by using the sample function controller. The numerical
results show that our control method is effective. We also find that the radial
ion density changes when the ion beam is in the channel: not only can the
halo-chaos and its regeneration be eliminated by using the sample
function control method, but also the density uniformity can be found at the
beam's centre as long as an appropriate control method is chosen.

The Chebyshev polynomial approximation is applied to investigate the stochastic
period-doubling bifurcation and chaos problems of a stochastic Duffing--van
der Pol system with bounded random parameter of exponential probability
density function subjected to a harmonic excitation. Firstly the stochastic
system is reduced into its equivalent deterministic one, and then the
responses of stochastic system can be obtained by numerical methods.
Nonlinear dynamical behaviour related to stochastic period-doubling
bifurcation and chaos in the stochastic system is explored. Numerical
simulations show that similar to its counterpart in deterministic nonlinear
system of stochastic period-doubling bifurcation and chaos may occur in the
stochastic Duffing--van der Pol system even for weak intensity of random
parameter. Simply increasing the intensity of the random parameter may
result in the period-doubling bifurcation which is absent from the
deterministic system.

In this paper a minority game (MG) is modified by adding into it some agents
who play a majority game. Such a game is referred to as a mix-game. The
highlight of this model is that the two groups of agents in the mix-game
have different bounded abilities to deal with historical information and to
count their own performance. Through simulations, it is found that the local
volatilities change a lot by adding some agents who play the majority game
into the MG, and the change of local volatilities greatly depends on
different combinations of historical memories of the two groups.
Furthermore, the analyses of the underlying mechanisms for this finding are
made. The applications of mix-game mode are also given as an example.

In this paper we present a model
with spatial heterogeneity based on cellular automata (CA). In the
model we consider the relevant heterogeneity of host (susceptible)
mixing and the natural birth rate. We divide the susceptible
population into three groups according to the immunity of each
individual based on the classical susceptible--infected--removed
(SIR) epidemic models, and consider the spread of an infectious
disease transmitted by direct contact among humans and vectors
that have not an incubation period to become infectious. We test
the local stability and instability of the disease-free
equilibrium by the spectrum radii of Jacobian. The simulation
shows that the structure of the nearest neighbour size of the cell
(or the degree of the scale-free networks) plays a very important
role in the spread properties of infectious disease. The positive
equilibrium of the infections versus the neighbour size follows
the third power law if an endemic equilibrium point exists.
Finally, we analyse the feature of the infection waves for the
homogeneity and heterogeneous cases respectively.

From the history of the theta--tau puzzle and the discovery of parity non-conservation in 1956, we review the current status of discrete symmetry violations in the weak interaction. Possible origin of these symmetry violations are discussed.

This paper proposes a deterministic quantum key distribution scheme based
on Gaussian-modulated continuous variable EPR correlations. This
scheme can implement fast and efficient key distribution. The
security is guaranteed by continuous variable EPR entanglement correlations
produced by nondegenerate optical parametric amplifier. For
general beam splitter eavesdropping strategy, the secret
information rate $\Delta I=I(\alpha,\beta)-I(\alpha,\epsilon)$ is
calculated in view of Shannon information theory. Finally the
security analysis is presented.

In this paper, the electronic states of the ground states and dissociation
limits of BC and BC$^-$ are correctly determined based on group theory and
atomic and molecular reaction statics. The equilibrium geometries, harmonic
frequencies and dissociation energies of the ground state of BC and BC$^-$
are calculated by using density function theory and quadratic CI method
including single and double substitutions. The analytical potential
energy functions of these states have been fitted with Murrell--Sorbie
potential energy function from our ab initio calculation results. The
spectroscopic data ($\alpha _\e $, $\omega _\e $ and $\omega _\e \chi _\e )$ of
each state is calculated via the relation between analytical potential
energy function and spectroscopic data. All the calculations are in good
agreement with the experimental data.

We have theoretically and experimentally studied the quantum coherence effects of
a degenerate transition $F_g = 3 \leftrightarrow F_e = 2$ system interacting
with a weak linearly polarized (with $\sigma _\pm $ components) probe light
and a strong linearly polarized (with $\sigma _\pm $ components) coupling
field. Due to the competition between the drive Rabi frequency and the
Zeeman splitting, electromagnetically induced transparency (EIT) and
electromagnetically induced absorption (EIA) are present at the different
values of applied magnetic field in the case where the Zeeman splitting of
excited state $\Delta e$ is larger than the Zeeman splitting of
ground state ${\Delta} g$ (i.e. ${\Delta} e > {\Delta} g)$.

In this paper the generation of four-wave mixing (FWM) signal using a
noncycling transition of caesium atoms is investigated when the pumping laser
is locked to the transition $6{\rm S}_{1/2}F=4\to6{\rm P}_{3/2}F'=4$, and
meanwhile the probe frequency is scanned across the $6{\rm S}_{1/2}F=4
\to6{\rm P}_{3/2}$ transition. The efficiency of the four-wave mixing signal
as a function of the intensity of the pumping beams and the detuning of the
pumping beams is also studied. In order to increase the detection
efficiency, a repumping laser which is resonant with $6{\rm S}_{1/2}
F=3\to 6{\rm P}_{3/2}F'=4$ transition is used. A theoretical model is also
introduced, and the theoretical results are in qualitative agreement with
experimental ones.

The luminescence of Er$^{3+}$:YAlO$_{3}$ in ultraviolet, visible and
infrared ranges
under the 518\,nm excitation
of the multiples $^{2}$H$_{11 / 2}$ have been investigated. Ultraviolet
(275\,nm and 318\,nm), violet
(405\,nm and 413\,nm) and blue (474\,nm) upconversion and infrared
downconversion luminescence has been observed. By means of measuring
the
fluorescence decay curves and using the theory of rate equations, the luminescence
kinetics was studied in detail and the processes of energy transfer upconversion
(ETU) and excitation state absorption (ESA) were proposed to explain the
upconversion phenomena.

A complex optical model potential modified by
incorporating the concept of bonded atom, which takes into consideration the
overlapping effect of electron clouds between two atoms in a molecule, is
first employed to calculate the total cross sections for electrons
scattering from such complex molecules as C$_{2}$H$_{6}$, C$_{2}$F$_{6}$,
C$_{6}$H$_{6}$ and C$_{6}$F$_{6}$ using the additivity rule model at
Hartree--Fock level over the energy range from 100~eV to 5000~eV. The
total cross sections are quantitatively compared with those obtained by
experiments wherever available, and they are in good agreement with
each other over a wide
energy range. It is shown that the modified potential together with the
additivity rule model is completely suitable for the calculation of
total cross sections
of electrons scattering from such complex molecules as
C$_{2}$H$_{6}$, C$_{2}$F$_{6}$, C$_{6}$H$_{6}$ and C$_{6}$F$_{6}$ above
200~eV--300~eV.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

In this paper, hollow and porous Cu$_{2}$O nanoparticles were prepared by
adjusting the cationic surfactant cetyltrimethylammonium (CTAB)
concentration in the solution-phase reaction. Structural investigations
reveal that Cu$_{2}$O nanoparticles can be either well-defined hollow
nanoboxes or porous nanocubes depending on the synthesis conditions. The
transmission electron microscopy (TEM) observations demonstrated that the
nanoparticles in general are composed of small grains coherently growing
along certain preferred orientations.

Through the investigation of the sample surface and interface of 3, 4, 9,
10-perylenetetracarboxylic dianhydride (PTCDA)/indium-tin-oxide (ITO) thin
films using atomic
force microscopy, it has been found that the surface is complanate, the
growth is uniform and the
defects cover basically the surface of ITO. Furthermore, the number of
pinholes is small. The
analysis of the sample surface and interface further verifies this result by
using x-ray
photoemission spectroscopy . At the same time, PTCDA is found to have the
ability of restraining
the diffusion of chemical constituents from ITO to the hole transport layer,
which is beneficial to
the improvement of the performance and the useful lifetime of the organic
light emitting
diodes (OLEDs).

In the classical
Peierls--Nabarro (P-N) theory of dislocation,
there is a long-standing contradiction that the stable configuration
of dislocation has maximum energy rather than minimum energy. In
this paper, the dislocation energy is calculated rigorously in the
context of the full lattice theory. It is found that besides the
misfit energy considered in the classical P-N theory, there is an
extra elastic strain energy that is also associated with the
discreteness of lattice. The contradiction can be automatically
removed provided that the elastic strain energy associated with the
discreteness is taken into account. This elastic strain energy is
very important because its magnitude is larger than the misfit
energy, its sign is opposite to the misfit energy. Since the elastic
strain energy and misfit energy associated with discreteness cancel
each other, and the width of dislocation becomes wide in the lattice
theory, the Peierls energy, which measures the height of the
effective potential barrier, becomes much smaller than that given in
the classical P-N theory. The results calculated here agree with
experimental data. Furthermore, based on the results obtained, a
useful formula of the Peierls stress is proposed to fully include
the discreteness effects.

Polycrystalline silicon (poly-Si) thin film has been prepared by means of
nickel-disilicide (NiSi$_{2})$ assisted excimer laser crystallization (ELC).
The process to prepare a sample includes two steps. One step consists of the
formation of NiSi$_{2}$ precipitates by heat-treating the dehydrogenated
amorphous silicon (a-Si) coated with a thin layer of Ni. And the other step
consists of the formation of poly-Si grains by means of ELC. According to
the test results of scanning electron microscopy (SEM), another grain growth
model named two-interface grain growth has been proposed to contrast with
the conventional Ni-metal-induced lateral crystallization (Ni-MILC) model and the
ELC model. That is, an additional grain growth interface other than that in
conventional ELC is formed, which consists of NiSi$_{2}$ precipitates and
a-Si. The processes for grain growth according to various excimer laser
energy densities delivered to the a-Si film have been discussed. It is
discovered that grains with needle shape and most of a uniform orientation
are formed which grow up with NiSi$_{2}$ precipitates as seeds. The reason
for the formation of such grains which are different from that of Ni-MILC without
migration of Ni atoms is not clear. Our model and analysis point out a
method to prepare grains with needle shape and mostly of a uniform
orientation. If such grains are utilized to make thin-film transistor,
its characteristics may be improved.

In this paper, we perform systematic calculations of the stress and strain
distributions in InAs/GaAs truncated pyramidal quantum dots (QDs) with
different wetting layer (WL) thickness, using the finite element method (FEM).
The stresses and strains are concentrated at the boundaries of the WL and
QDs, are reduced gradually from the boundaries to the interior, and tend to
a uniform state for the positions away from the boundaries. The maximal
strain energy density occurs at the vicinity of the interface between the WL
and the substrate. The stresses, strains and released strain energy are
reduced gradually with increasing WL thickness. The above results show that
a critical WL thickness may exist, and the stress and strain distributions
can make the growth of QDs a growth of strained three-dimensional island
when the WL thickness is above the critical value, and FEM can be applied to
investigate such nanosystems, QDs, and the relevant results are supported by
the experiments.

In this paper intrinsic microcrystalline silicon films have been prepared by very high
frequency plasma enhanced chemical vapour deposition (VHF-PECVD) with
different substrate temperature and pressure. The film properties were
investigated by using Raman spectra, x-ray diffraction, scanning
electron microscope (SEM), and optical
transmittance measurements, as well as dark conductivity. Raman results
indicate that increase of substrate temperature improves the microcrystallinity
of the film. The crystallinity is improved when the pressure increases from
50Pa to 80Pa and the structure transits from microcrystalline to amorphous
silicon for pressure higher than 80Pa. SEM reveals the effect of substrate
temperature and pressure on surface morphology.

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

The Schottky photodetector was fabricated on GaN epilayers grown by
metalorganic chemical vapour deposition (MOCVD). The spectral response of the
Schottky photodetector was characterized. A new model is proposed to
interpret the characteristic of the spectral response curve of the Schottky
photodetectors by introducing a penetrating distance of an incident light at
a certain wavelength in the current continuity equation and the interface
recombination at the metal--semiconductor rectifying contact. The expressions
for the spectral response of the Schottky photodetector are deduced and used
successfully to fit the experimental data.

This paper found that the crystalline volume ratio ($X_{\rm c}$) of $\mu$c-Si
deposited on SiN$_x$ substrate is higher than that on 7059 glass. At the same
silane concentration (SC) (for example, at SC=2{\%}), the $X_{\rm c}$ of $\mu$c-Si
deposited on SiN$_x$ is more than 64{\%}, but just 44{\%} if deposited on
Conning 7059. It considered that the `hills' on SiN$_x$ substrate
would promote the
crystalline growth of $\mu$c-Si thin film, which has been confirmed by
atomic force microscope (AFM)
observation. Comparing several thin film transistor (TFT) samples whose
active-layer were deposited
under various SC, this paper found that the appropriate SC for the
$\mu$c-Si thin
film used in TFT as active layer should be more than 2{\%}, and $X_{\rm c}$ should be
around 50\%. Additionally, the stability comparison of $\mu$c-Si TFT and
a-Si TFT is shown in this paper.

This paper reports that InAs/In$_{0.53}$Ga$_{0.47}$As/AlAs resonant tunnelling diodes have
been grown on InP substrates by molecular beam epitaxy. Peak to valley
current ratio of these devices is 17 at 300K. A peak current density of
3kA/cm$^{2}$ has been obtained for diodes with AlAs barriers of ten
monolayers, and an In$_{0.53}$Ga$_{0.47}$As well of eight monolayers with
four monolayers of InAs insert layer. The effects of growth interruption for
smoothing potential barrier interfaces have been investigated by high
resolution transmission electron microscope.

A novel vertical stack heterostructure CMOSFET is investigated, which is
structured by strained SiGe/Si with a hole quantum well channel in the
compressively strained Si$_{1 - x}$Ge$_{x}$ layer for p-MOSFET and an electron
quantum well channel in the tensile strained Si layer for n-MOSFET. The device
possesses several advantages including: 1) the integration of electron
quantum well channel with hole quantum well channel into the same vertical
layer structure; 2) the gate work function modifiability due to the
introduction of poly-SiGe as a gate material; 3) better transistor matching;
and 4) flexibility of layout design of CMOSFET by adopting exactly the same
material lays for both n-channel and p-channel. The MEDICI simulation result
shows that p-MOSFET and n-MOSFET have approximately the same matching
threshold voltages. Nice performances are displayed in transfer
characteristic, transconductance and cut-off frequency. In addition, its
operation as an inverter confirms the CMOSFET structured device to be normal
and effective in function.

In this paper the magnetic properties of a three layer superlattice with the crystal field on
the honeycomb and square lattice have been studied based on the
effective-field theory with self-spin correlations and the differential
operator technique. The effects of the crystal field and longitudinal
magnetic field on the susceptibility are discussed in detail. A number of
interesting phenomena, originating from the competition between the
longitudinal magnetic field, crystal-field, and coordination number, have
been found.

The dependences of soft magnetic properties and microstructures of the
sputtered FeCo (=Fe$_{65}$Co$_{35}$) films on Co underlayer thickness
$t_{\rm Co}$, FeCo thickness $t_{\rm FeCo}$, substrate temperature
$T_{\rm s}$ and target-substrate spacing $d_{\rm T-S}$ are studied.
FeCo single layer generally shows a high coercivity with no obvious
magnetic anisotropy. Excellent soft magnetic properties with
saturation magnetization $\mu_{0}M_{\rm s}$ of 2.35 T and
hard axis coercivity $H_{\rm ch}$ of 0.25 kA/m in FeCo films can be
achieved by introducing a Co underlayer. It is shown that sandwiching
a Co underlayer causes a change in orientation and reduction in grain size from 70 nm to
about 10 nm in the FeCo layer. The magnetic softness can be explained by the
Hoffmann's ripple theory due to the effect of grain size. The magnetic
anisotropy can be controlled by changing $d_{\rm T-S}$, and a maximum of
14.3 kA/m for anisotropic field $H_{\rm k}$ is obtained
with $d_{\rm T-S}$=18.0 cm.

The equivalent circuit with complex physical constants for a piezoelectric
ceramic in thickness mode is established. In the equivalent circuit,
electric components (equivalent circuit parameters) are connected to real
and imaginary parts of complex physical coefficients of piezoelectric
materials. Based on definitions of dissipation factors, three of them
(dielectric, elastic and piezoelectric dissipation factors) are represented
by equivalent circuit parameters. Since the equivalent circuit parameters
are detectable, the dissipation factors can be easily obtained. In the
experiments, the temperature and the stress responses of the three
dissipation factors are measured.

The temperature gradients that arise in the paraelectric--ferroelectric
interface dynamics induced by the latent heat transfer are studied from the
point of view that a ferroelectric phase transition is a stationary,
thermal-electric coupled transport process. The local entropy production is
derived for a ferroelectric phase transition system from the Gibbs equation.
Three types of regions in the system are described well by using the Onsager
relations and the principle of minimum entropy production. The
theoretical results coincides with the experimental ones.

This paper reports on the n-type ZnS used as electron transport layer
for the organic light-emitting diodes (OLEDs). The naphthyl-substituted
benzidine derivative (NPB) and tris (8-hydroxyquinoline) aluminium
(Alq$_{3})$ are used as the hole transport layer and the emitting layer
respectively. The insertion of the n-type ZnS layer enhances the electron
injection in the OLEDs. The study was carried out on OLEDs of structures:
indium--tin-oxide (ITO)/NPB/Alq$_{3}$/ZnS/LiF/AL, ITO/NPB/Alq$_{3}$/LiF/AL
and ITO/NPB/Alq$_{3}$/AL. The luminance and efficiency of the device
containing this electron transport layer are increased significantly over
those obtained from conventional devices due to better carrier balance.

The role of hydrogen in hydrogenated microcrystalline silicon ($\mu $c-Si:H)
thin films in deposition processes with very high frequency
plasma-enhanced chemical vapour deposition (VHF-PECVD) technique have been
investigated in this paper. With \textit{in situ} optical emission spectroscopy (OES)
diagnosis during the fabrication of $\mu $c-Si:H thin films under different
plasma excitation frequency $\nu _{\rm e }$ (60MHz--90MHz), the
characteristic peak intensities ($I_{{\rm SiH}^*}$, $I_{{\rm H}\alpha^*}$
and $I_{{\rm H}\beta ^*}$) in SiH$_{4}$+H$_{2}$ plasma and the ratio
of ($I_{{\rm H}\alpha^* }$ +
$I_{{\rm H}\beta^*}$) to $I_{{\rm SiH}^*}$ were measured; all the characteristic peak
intensities and the ratio ($I_{{\rm H}\alpha^* }$
+ $I_{{\rm H}\beta^* }$)/$I_{{\rm SiH}^*}$ are
increased with plasma excitation frequency. It is identified that high
plasma excitation frequency is favourable to promote the decomposition of
SiH$_{4}$+H$_{2 }$ to produce atomic hydrogen and SiH$_x$ radicals. The
influences of atomic hydrogen on structural properties and that of SiH$_x$
radicals on deposition rate of $\mu $c-Si:H thin films have been studied
through Raman spectra and thickness measurements, respectively. It can
be concluded that both the crystalline volume fraction and deposition rate
are enhanced with the increase of plasma excitation frequency, which is in
good accord with the OES results. By means of FTIR measurements, hydrogen
contents of $\mu $c-Si:H thin films deposited at different plasma
excitation frequency have been evaluated from the integrated intensity of
wagging mode near 640 cm$^{ - 1}$. The hydrogen contents vary from 4{\%} to 5{\%},
which are much lower than those of $\mu $c-Si:H
films deposited with RF-PECVD technique. This implies that $\mu $c-Si:H thin
films deposited with VHF-PECVD technique usually have good stability under
light-soaking.

Extreme sensitivity to initial values is an intrinsic character of
chaotic systems. The evolution of a chaotic system has a
spatiotemporal structure containing quasi-periodic changes of
different spatiotemporal scales. This paper uses an empirical mode
decomposition (EMD) method to decompose and compare the evolution of
the time-dependent evolutions of the $x$-component of the Lorenz system.
The results indicate that the sensitivity of
intrinsic mode function (IMF) component is dependent on initial
values, which provides some scientific evidence for the possibility
of long-range climatic prediction.

The technique of optical tweezers has been improved a lot since its
invention, which extends the application fields of optical tweezers. Besides
the conventionally used Gaussian beams, different types of ring beams have also been
used to form optical tweezers for different purposes. The two typical
kinds of ring beams used in optical tweezers are the hollow Gaussian beam and
Laguerre--Gaussian (LG) beam. Both theoretical computation and experiments
have shown that the axial trapping force is improved for the ring beams
compared with the Gaussian beam, and hence the trapping stability is
improved, although the transverse trapping forces of ring beams are smaller
than that of Gaussian beam. However, no systematic study on the trapping
forces of ring beam has ever been discussed. In this article, we will investigate
the axial and transverse trapping forces of different types of ring beams
with different parameters systematically, by numerical computation in which
the ray optics model is adopted. The spherical aberration caused by the
refractive index mismatch between oil and water is also considered in the
article. The trapping forces for different objectives that obey the sine
condition and tangent condition are also compared with each other.
The result of systematical calculation will be useful for the applications
of optical tweezers formed by different types of ring beams.