The electronic structures of coupled quantum dots grown on (11N)-oriented substrates are studied in the framework of effective-mass envelope-function theory. The results show that the all-hole subbands have the smallest widths and the optical properties are best for the (113), (114), and (115) growth directions. Our theoretical results agree with the available experimental data. Our calculated results are useful for the application of coupled quantum dots in photoelectric devices.

In this pager a pure algebraic method implemented in a computer
algebraic system, named multiple Riccati equations rational
expansion method, is presented to construct a novel class of
complexiton solutions to integrable equations and nonintegrable
equations. By solving the (2+1)-dimensional dispersive long wave
equation, it obtains many new types of complexiton solutions such as
various combination of trigonometric periodic and hyperbolic
function solutions, various combination of trigonometric periodic
and rational function solutions, various combination of hyperbolic
and rational function solutions, etc.

Using unitary transformations, this paper obtains the eigenvalues
and the common eigenvector of Hamiltonian and a new-defined generalized
angular momentum (L_{z}) for an electron confined in quantum
dots under a uniform magnetic field (UMF) and a
static electric field (SEF). It finds that the eigenvalue of
L_{z} just stands for the expectation value of a usual angular
momentum l_{z} in the eigen-state. It first obtains the matrix
density for this system via directly calculating a transfer matrix
element of operator \exp( -\beta H) in some representations with
the technique of integral within an ordered products (IWOP) of
operators, rather than via solving a Bloch equation. Because the
quadratic homogeneity of potential energy is broken due to the
existence of SEF, the virial theorem in statistical physics is not
satisfactory for this system, which is confirmed through the
calculation of thermal averages of physical quantities.

Based on two mutually conjugate entangled state representations, we
establish the path integral formalism for some Hamiltonians of
quantum optics in entangled state representations. The Wigner
operator in the entangled state representation is presented. Its
advantages are explained.

We employ the parallel computing technology to study numerically the
three-dimensional structure of quantized vortices of Bose--Einstein
condensates. For anisotropic cases, the bending process of vortices
is described in detail by the decrease of Gross--Pitaevskii energy. A
completely straight vortex and the steady and symmetrical
multiple-vortex configurations are obtained. We analyse the effect of
initial conditions and angular velocity on the number and shape of
vortices.

Following a recent proposal ( Phys. Lett. A 346
(2005) 330) about quantum dense coding using a tripartite
entangled GHZ state and W state, this paper proposes an
experimentally feasible scheme for dense coding in cavity QED by
using another peculiar tripartite entangled state. In the scheme
the atoms interact simultaneously with a highly detuned cavity
mode with the assistance of a classical field, the successful
probability of dense coding scheme with this peculiar tripartite
entangled state equals 1.

This paper shows the Fokker--Planck equation of a dynamical system
driven by coloured cross-correlated white noises in the absence and
presence of a small external force. Based on the Fokker--Planck
equation and the definition of Shannon's information entropy, the
time dependence of entropy flux and entropy production can be
calculated. The present results can be used to explain the extremal
behaviour of time dependence of entropy flux and entropy production
in view of the dissipative parameter γ of the system, coloured
cross-correlation time \tau and coloured cross-correlation strength
\la.

In this paper, a simple model for the strength dynamics of weighted evolving
networks is proposed to characterize the weighted networks. By considering
the congestion effects, this approach can yield power law strength
distribution appeared on the many real weighted networks, such as traffic
networks, internet networks. Besides, the relationship between strength and
degree is given. Numerical simulations indicate that the strength
distribution is strongly related to the strength dynamics decline. The model
also provides us with a better description of the real weighted networks.

A new GaAs(100) spin polarized electron source with an optical
polarimeter, which is employed in the field of polarized electron
and gas atom collision, is presented in detail. The apparatus is
passive-magnetic-shielded by a box and a cylinder made of
nickel--iron--molybdenum soft magnetic alloy without Helmholtz coil
arrangement. And a uniformly distributed residual magnetic field of
less than 5×10^{-7},T is obtained near the collision area. The
spin polarized electron beam is transmitted and focused onto
collision point from photocathode by a set of electron optics with
more than 25% transmission 95cm distance through an 1mm
diameter aperture. Construction and operation of the apparatus, such
as vacuum and magnetic shielding system, photocathode, laser optics,
electron optics and polarimeter are discussed. The polarization of
the spin polarized electron beam is determined to be 30.8\pm3.5%
measured with a He optical polarimeter.

This paper presents a study on `hard' and `soft' interactions in
pp (pp) collisions using a phenomenological model of HIJING, the
jet-cone reconstruction method is employed to select the `hard' and
`soft' event sub-samples from minimum bias events. It is found that
the HIJING model can reproduce the energy scaling behaviour of mean
transverse momentum (< p_{T}>) distributions of charged
hadrons versus multiplicity (N_{ch}) in `soft' events. From the
PYTHIA simulation comparing with the HIJING model, the enhancement of
the kaon and proton yields from `hard' interactions comparing with
`soft' interactions is observed to be due to the mini-jets effect.
These mechanisms responsible for the increase of charged hadron's

T> are different in `soft' and `hard' interactions.

The desirable physical properties of hardness, high temperature
stability, and conductivity make the early transition metal nitrides
important materials for various technological applications. To learn
more about the nature of these materials, the local-density
approximation(LDA) and GW approximation i.e. combination of the
Green function G and the screened Coulomb interaction W, have been
performed. This paper investigates the bulk electronic and physical
properties of early transition metal mononitrides, ScN and YN in the
rocksalt structure. In this paper, the semicore electrons are
regarded as valance electrons. ScN appears to be a semimetal, and YN
is semiconductor with band gap of 0.142eV within the LDA, but are
in fact semiconductors with indirect band gaps of 1.244 and
0.544\,eV respectively, as revealed by calculations performed using
GW approximation.

This paper calculates the lifetime of resonant state and
transmission probability of a single electron tunnelling in a
spherical quantum dot (SQD) structure by using the transfer matrix
technique. In the SQD, the electron is confined both transversally
and longitudinally, the motion in the transverse and longitudinal
directions is separated by using the adiabatic approximation theory.
Meanwhile, the energy levels of the former are
considered as the
effective confining potential. The numerical calculations are carried out
for the SQD consisting of GaAs/InAs material. The obtained results show that the
bigger radius of the quantum dot not only leads significantly to the shifts
of resonant peaks toward the low-energy region, but also causes the
lengthening of the lifetime of resonant state. The lifetime of resonant
state can be calculated from the uncertainty principle between the energy
half width and lifetime.

We used the close-coupling optical (CCO) approach to investigate the
open-shell carbon atom. The elastic cross sections have been
presented at the energies below 90eV, and the present CCO results
have been compared with other theoretical results. We found that
polarization and the continuum states have significant contributions
to the elastic cross sections. The present calculations show that the
CCO method is capable of calculating electron scattering from
open-shell atoms.

The structural relaxation of a cluster containing 55 atoms at elevated
temperatures is simulated by molecular dynamics. The interatomic
interactions are given by using the embedded atom method (EAM) potential. By
decomposing the peaks of the radial distribution functions (RDFs) according
to the pair analysis technique, the local structural patterns are identified
for this cluster. During increasing temperature, structural changes of
different shells determined by atom density profiles result in an abrupt
increase in internal energy. The simulations show how local structural
changes can strongly cause internal energy to change accordingly.

In this paper high-order harmonic generation (HHG) spectra and the
ionization probabilities of various charge states of small cluster
Na_{2} in the multiphoton regimes are calculated by using
time-dependent local density approximation (TDLDA) for one-colour
(1064 nm) and two-colour (1064 nm and 532 nm) ultrashort (25 fs)
laser pulses. HHG spectra of Na_{2} have not the large extent of
plateaus due to pronounced collective effects of electron dynamics.
In addition, the two-colour laser field can result in the breaking of
the symmetry and generation of the even order harmonic such as the
second order harmonic. The results of ionization probabilities show
that a two-colour laser field can increase the ionization probability
of higher charge state.

This paper investigates the properties of the ultrashort pulsed beam aimed to the
capture-and-acceleration-scenario (CAS) vacuum electron acceleration. The result
shows that the spatiotemporal distribution of the phase velocity, the longitudinal
component of the electric field and the acceleration quality factor are
qualitatively similar to that of the continuous-wave Gaussian beam, and are slightly
influenced by the spatiotemporal coupling of the ultrashort pulsed beam. When the
pulse is compressed to an ultrashort one in which the pulse duration T_{FWHM}
<5T_{0}, the variation of the maximum net energy gain due to the
carrier-envelope phase is a crucial disadvantage in the CAS acceleration process.

The microstructure and optical properties of Ni-doped SnO_{2}
nano-powders are studied in detail. By Ni-doping, not only the grain
size reduces, but also the grain shape changes from nano-rods to
spherical particles. The crystallization becomes better with
annealing temperature increasing. The band gap energy decreases as
nickel doping level increases. The sp--d hybridization and alloying
effect due to amorphous SnO_{2-X} phase should be responsible for
the band gap narrowing effect. Nickel dopant does not change the
photoluminescence (PL) peak positions.

Based on a modified coupled wave theory of Kogelnik, we have studied
the diffraction of an ultrashort pulsed beam with an arbitrary
polarization state from a volume holographic grating in
photorefractive LiNbO_{3} crystals. The results indicate that the
diffracted intensity distributions in the spectral and temporal
domains and the diffraction efficiency of the grating are both
changed by the polarization state and spectral bandwidth of the input
pulsed beam. A method is given of choosing the grating parameters and
input conditions to obtain a large variation range of the spectral
bandwidth of the diffracted pulsed beam with an appropriate
diffraction efficiency. Our study presents a possibility of using a
volume holographic grating recorded in anisotropic materials to shape
a broadband ultrashort pulsed beam by modulating its polarization
state.

In this paper, we study the nonclassical properties of the
electromagnetic field resulting from the interaction of a
three-level Λ-type atom with a two-mode field initially
in the coherent state, such as squeezing properties and
sub-Poisson statistics. We show that the squeezing can be
enhanced by selective atomic measurement.

By introducing the von Neumann entropy as a measure of the extent of
noise, this paper discusses the entropy evolution in a two-level
quantum feedback controlled system. The results show that the
feedback control can induce the reduction of the degree of noise, and
different control schemes exhibit different noise controlling
ability, the extent of the reduction also related with the position
of the target state on the Bloch sphere. It is shown that the
evolution of entropy can provide a real time noise observation and a
systematic guideline to make reasonable choice of control strategy.

A scheme for teleporting an arbitrary n-bit one-photon and vacuum entangled
Greenberger--Horne--Zeilinger (GHZ) state is proposed. In this scheme, the
maximum entanglement GHZ state is used as a quantum channel. We find a
method of distinguishing four Bell states just by detecting the atomic
states three times, which is irrelevant to the qubit number of the state to
be teleported.

Stochastic resonance (SR) is studied in a gain--noise model of a
single-mode laser driven by a coloured pump noise and a quantum noise
with cross-correlation between real and imaginary parts under a
direct signal modulation. By using a linear approximation method, we
find that the SR appears during the variation of signal-to-noise
ratio (SNR) separately with the pump noise self-correlation time
\tau , the noise correlation coefficient between the real part and
the imaginary part of the quantum noise \lambda_{q} , the
attenuation coefficient \gamma and the deterministic steady-state
intensity I_0 . In addition, it is found that the SR can be
characterized not only by the dependence of SNR on the noise
variables of \tau and \lambda_{q}, but also by the
dependence of SNR on the laser system variables of \gamma and I_{0}. Thus our investigation extends the characteristic quantity of SR
proposed before.

Absorption and refraction of the inner transition F_{2}\leftrightarrow
F_{3} of the closed four level N-type atom have been investigated under a
weak field. The outer transitions F_{1}\leftrightarrow F_{3} and
F_{2}\leftrightarrow F_{4} are resonantly interacted with drive field with
frequency \omega_{c} and Rabi frequency \Omega_{c}, and saturation
field with \Omega_{s} and \Omega_{s}, respectively. For the suitable Rabi
frequencies \Omega_{c} and \Omega_{s}, we obtain
the Mollow absorption
spectrum of probe field. The reason is that the drive field excites the atom
to the upper level F_{c} and simultaneously the saturation field takes
the atom out of the lower level F_{2}, leading to the stimulated emission.
Meanwhile, due to the dynamic energy splitting induced by the drive and
saturation fields, the two- and four-peaked absorption spectra are observed.
At the zero off-resonance detuning of probe field, we also find the transfer
of dispersion from negative to positive with an increment of \Omega_{s}.
Finally, the refractive index enhancement is predicted for a wide spectral
region.

This paper studies the focusing properties of Gaussian Schell-model
(GSM) beams by an astigmatic aperture lens. It is shown that the
axial irradiance distribution, the maximum axial irradiance and its
position of focused GSM beams by an astigmatic aperture lens depend
upon the astigmatism of the lens, the coherence of partially
coherent light, the truncation parameter of the aperture and Fresnel
number. The numerical calculation results are given to illustrate
how these parameters affect the focusing property.

Starting from the vectorial Rayleigh--Sommerfeld integrals, the
free-space propagation expressions for vectorial
Hermite--Laguerre--Gaussian (HLG) beams beyond the paraxial
approximation are derived. The far-field expressions and the
scalar paraxial results are given as special cases of our
general expressions. The intensity distributions of vectorial
nonparaxial HLG beams are studied and illustrated with numerical
examples.

This paper investigates the adjacent interactions of three novel solitons for the
quintic complex Ginzburg--Landau equation, which are plain pulsating,
erupting and creeping solitons. It is found that different
performances are presented for different solitons due to isolated regions of
the parameter space where they exist. For example, plain pulsating and
erupting solitons exhibit mutual annihilation during collisions with the
decrease of total energy, but for creeping soliton, the two adjacent
pulses present soliton fusion without any loss of energy. Otherwise, the
method for restraining the interactions is also found and it can suppress
interactions between these two adjacent pulses effectively.

In order to measure the Brillouin frequency shift (BFS) of the
medium, this paper proposes a method using mixtures in a two-cell
stimulated Brillouin scattering system, which uses a medium to be
measured as amplifier medium and a mixture medium as generator
medium. The seed light from the generator gains effective
amplification in the amplifier and the amplification ratio changes
with the mixing fraction. Only when the BFS of the mixture medium is
equal to that of the medium in the amplifier does the seed light
obtain the maximum amplification ratio. The method has the advantage
of independence of the wavelength of the incident light.

This paper predicts that grey spatial solitons can exist in
two-photon photorefractive materials. In steady state and under
appropriate external bias conditions, it obtains the grey spatial
soliton solutions of the optical wave evolution equation. The
intensity profile, phase distribution，and transverse velocity of
these grey solitons are discussed.

The dynamical evolution of both signal and pump beams are traced
by numerically solving the coupled-wave equation for a
photorefractive two-wave mixing system. The direct simulations
show that, when the intensity ratio of the pump beam to the
signal beam is large enough, the pump beam presents a common
decaying behaviour without modulational instability (MI), while
the signal beam can evolve into a quasistable spatial soliton
within a regime in which the pump beam is depleted slightly. The
larger the ratio is, the longer the regime is. Such quasistable
solitons can overcome the initial perturbations and numerical
noises in the course of propagation, perform several cycles of
slow oscillation in intensity and width, and persist over tens
of diffraction lengths. From physical viewpoints, these solitons
actually exist as completely rigorous physical objects. If the
ratio is quite small, the pump beam is apt to show MI, during
which the signal beam experiences strong expansion and shrinking
in width and a drastic oscillation in intensity, or completely
breaks up. The simulations using actual experimental parameters
demonstrate that the observation of an effectively stable
soliton is quite possible in the proposed system.

We have discussed theoretically the negative refraction in finite
one-dimensional (1D) photonic crystals (PCs) composed of alternative
layers with high index contrast. The frequency bands of negative
refraction are obtained with the help of the photonic band structure,
the group velocity and the power transmittance, which are all
obtained in analytical expression. There shows negative transverse
position shift at the endface when negative refraction occurs, which
is analysed in detail.

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

Non-steady interactions between plasmas and aircraft in its near wake region
are investigated in detail. Under the non-static limit, a set of equations
that describe these interactions are obtained. The results of the numerical
simulation show that the cavitons of transverse plasmas are excited and
density cavitons appear when the envelope of plasma becomes sufficiently
intensive. This is very important for detecting the moving body that has a
`stealth' characteristic.

In the present paper, a physical model is proposed for reducing the
problem of the drag reduction of an attached bow shock around the
nose of a high-speed vehicle with on-board discharge, to the problem
of a balance between the magnetic pressure and gas pressure of plane
shock of a partially ionized gas consisting of the environmental gas
around the nose of the vehicle and the on-board discharge-produced
plasma. The relation between the shock strength and the
discharge-induced magnetic pressure is studied by means of a set of
one-fluid, hydromagnetic equations reformed for the present purpose,
where the discharge-induced magnetic field consists of the electron
current (produced by the discharge)-induced magnetic field and the
partially ionized gas flow-induced one. A formula for the relation
between the above parameters is derived. It shows that the
discharge-induced magnetic pressure can minimize the shock strength,
successfully explaining the two recent experimental observations on
attached bow shock mitigation and elimination in a supersonic flow
during on-board discharge [Phys. Plasmas 9 (2002) 721 and
Phys. Plasmas 7 (2000) 1345]. In addition, the formula
implies that the shock elimination leaves room for a layer of
higher-density plasma rampart moving around the nose of the vehicle,
being favourable to the plasma radar cloaking of the vehicle. The
reason for it is expounded.

Diffusive heat waves play an important role in radiation
hydrodynamics. In low density material, it may be possible that the
radiative energy flux dominates the material energy flux and thus
energy flow can be determined. In this paper by means of a simple
algebraic method, the expressions characterizing the condition of
diffusion approximation and supersonic transport of heat wave are
found. In this case, the ratio of the radiative energy flux to the
material energy flux is directly proportional to the product of Mach
number M multiplied by optical depth \tau. And it may also be
expressed by radiation temperature heating material. The material
density and length may be determined in order to achieve
above-mentioned conditions when the driven temperature and duration
are given.

HL-2A tokamak is the first tokamak with divertors in China. The
plasma boundary and the position of the striking point on the target
plates of the HL-2A closed divertor were simulated by the current
filament code and they were in agreement with the diagnostic results
in the divertor. Supersonic molecular beam injection (SMBI) system
was first installed and tested on the HL-2A tokamak in 2004. In the
present experiment low pressure SMBI fuelling on the HL-2A closed
divertor was carried out. The experimental results indicate that the
divertor was operated in the `linear regime' and during the period of
SMB pulse injection into the HL-2A plasma the power density convected
at the target plate surfaces was 0.4 times of that before or after
the beam injection. It is a useful fuelling method for decreasing the
heat load on the neutralizer plates of the divertor.

It is difficult to obtain the asymmetrical factor along the
observation direction parallel to the plasma mid-plane when the
detected radiation is also in the mid-plane. This paper
considers the magnetic surfaces and Grad--Shafranov shift, and
develops a new method for inverse asymmetric electron density
information, during magnetic equilibrium configuration in a
tokamak.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

This paper reports that an atomic scale study of [\bar {1}10]
symmetrical tilt grain
boundary (STGB) has been made with modified analytical embedded atom
method (MAEAM) for 44 planes in three noble metals Au, Ag and Cu. For
each metal, the energies of two crystals ideally joined together are
unrealistically high due to very short distance between atoms near
the grain boundary (GB) plane. A relative slide between grains in the
GB plane results in a significant decrease in GB energy and a minimum
value is obtained at specific translation distance. The minimum
energy of Cu is much higher than that of Ag and Au, while the minimum
energy of Ag is slightly higher than that of Au. For all the three
metals, the three lowest energies correspond to identical (111),
\mbox(113) and \mbox(331) boundary successively for two
translations considered; from minimization of GB energy, these
boundaries should be preferable in [\bar {1}10] STGB for noble
metals. This is consistent with the experimental results. In
addition, the minimum energy increases with increasing reciprocal
planar coincidence density \Sigma, but decreases with
increasing relative interplanar distance d /a.

The elastic constants and thermodynamic properties of c-BN are
calculated using the first-principles plane wave method with the
relativistic analytic pseudopotential of the Hartwigen, Goedecker
and Hutter (HGH) type in the frame of local density approximation
and using the quasi-harmonic Debye model, separately. Moreover, the
dependences of the normalized volume V/V_{0} on pressure P, as
well as the bulk modulus B, the thermal expansion α, and the
heat capacity C_{V} on pressure P and temperature T are also
successfully obtained.

This paper studies the evolution of wave in the system of a pure
anharmonic lattice with a double well on-site potential by numerical
calculation. It finds that an initial distribution of static or
moving wave can evolve into two travelling soliton-like trains with
contrary directions and a region of oscillation in this lattice
system. It presents that some cases with cosine-square-shape and
Gaussian-shape initial distribution of static or moving wave will
produce ordered soliton-like train. Careful numerical observation
shows that the centre oscillation region in this system may act as a
resource of generating soliton-like train.

The discrete gap breathers (DGBs) in a one-dimensional diatomic chain
with K_{2}--K_{32}--K_{4} potential are analysed. Using the
local anharmonicity approximation, the analytical investigation has
been implemented. The dependence of the central amplitude of the
discrete gap breathers on the breather frequency and the localization
parameter are calculated. With increasing breather frequency, the DGB
amplitudes decrease. As a function of the localization parameter, the
central amplitude exhibits bistability, corresponding to the two
branches of the curve \omega = \omega (\zeta). With a nonzero cubic
term, the HS mode of DGB profiles becomes weaker. With increasing
$K_{3}$, the HS mode of DGB profiles becomes weaker and a bit
narrower. For the LS mode, with increasing K_{3}, the central
particle amplitude becomes larger, and the DGB profile becomes much
sharper. But, as k_{3} increases further, the central particle
amplitude of the LS mode becomes smaller.

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

A number of researchers have reported discrepancies between surface
resistance (SR) measurements and classical theoretical predictions in
normal metals for millimetre wavelengths (MW). In this paper, a
rigorous model is developed for analysing SR of normal metals. This
model is based on quantum mechanical analysis of the spatial
dispersion within the metal. We use the model to predict SR and
eliminate the discrepancies between SR measurements and classical
theoretical predictions in normal metals for MW. Moreover, we have
compared the results of this model with that of the classical
skin-effect model and classical relaxation-effect model. Our analysis
shows that the conductivity is not only frequency- but also
wave-vector-dependent for MW. We demonstrate that our model has good
quantitative agreement with the published experimental data for the
room temperature surface resistance of normal metals for MW.

In this paper, we propose a novel Schottky barrier MOSFET structure,
in which the silicide source/drain is designed on the buried metal
(SSDOM). The source/drain region consists of two layers of silicide
materials. Two Schottky barriers are formed between the silicide
layers and the silicon channel. In the device design, the top barrier
is lower and the bottom is higher. The lower top contact barrier is
to provide higher {on-state} current, and the higher bottom contact
barrier to reduce the off-state current. To achieve this, ErSi is
proposed for the top silicide and CoSi_{2} for the bottom in the
n-channel case. The 50~nm n-channel SSDOM is thus simulated to
analyse the performance of the SSDOM device. In the simulations, the
top contact barrier is 0.2e~V (for ErSi) and the bottom barrier is
0.6eV (for CoSi_{2}. Compared with the corresponding conventional
Schottky barrier MOSFET structures (CSB), the high on-state
current of the SSDOM is maintained, and the off-state current is
efficiently reduced. Thus, the high drive ability (1.2mA/μm
at V_{ds}=1V,
V_{gs}=2V) and the high I_{on}/I_{min} ratio (10^{6})
are both achieved by applying the SSDOM
structure.

This paper reports that the high-K HfO_{2} gate dielectrics are fabricated on
n-germanium substrates by sputtering Hf on Ge and following by a furnace
annealing. The impacts of sputtering ambient, annealing ambient and
annealing temperature on the electrical properties of high-K HfO_{2} gate
dielectrics on germanium substrates are investigated. Experimental results
indicate that high-K HfO_{2} gate dielectrics on germanium substrates with
good electrical characteristics are obtained, the electrical properties of
high-K HfO_{2} gate dielectrics is strongly correlated with sputtering
ambient, annealing ambient and annealing temperature.

Optical responses in dilute composites are controlled through the
local dielectric resonance of metallic clusters. We consider two
located metallic clusters close to each other with admittances
\varepsilon_{1} and \varepsilon_{2}. Through varying the
difference admittance ratio \eta [ = (\varepsilon_{2}- \varepsilon
_{0}) / (\varepsilon_{1}- \varepsilon_{0})], we find that their
optical responses are determined by the local resonance. There is a
blueshift of absorption peaks with the increase of \eta.
Simultaneously, it is known that the absorption peaks will be
redshifted by enlarging the cluster size. By adjusting the
nano-metallic cluster geometry, size and admittances, we can control
the positions and intensities of absorption peaks effectively. We
have also deduced the effective linear optical responses of
three-component composites \varepsilon_{e}= \varepsilon_{0}
\bigl(1 + \sum_{n=1}^{n_{s}} [(\gamma_{n2}+ \eta \gamma_{n2})/({\varepsilon_{0}(s - s_{n}))]} \bigr), and the sum
rule of cross sections: \sum_{n=1}^{n_{s}} {(\gamma_{n2}+
\eta \gamma_{n2} ) = N_{h1}+ N_{h2}, where N_{h1}and
N_{h2} are the numbers of \varepsilon_{1} and \varepsilon_{2}
bonds along the electric field, respectively. These results may be
beneficial to the study of surface plasmon resonances on a nanometre
scale.

The double-doped
La_{2/3+4x/3}Sr_{1/3-4x/3}Mn_{1-x}Mg_{x}O_{3} samples with
fixed Mn^{3+}/Mn^{4+} ratio equal to 2/1 are investigated by
means of magnetism and transport measurements. Phase separation is
observed at temperature higher than T_{c}^{onset} for
x=0.10 and 0.15. For x=0.10, rather strong phase separation
induces drastic magnetic random potential and results in the
localization of carriers. Thus, the variable-range hopping process
dominates. For other samples, there is no or only weak phase
separation above T_{c}^{onset}. Thus, thermal activation
mechanism is responsible for the high temperature transport
behaviour. For x=0.20 and 0.25, unexpected AFM behaviour is
observed at low temperature. All these results are well understood by
considering the special role of the ``double-doping".

8000 CROSSDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY

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