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Ti2AlC/TiAl composites with different volume fractions were prepared by hot pressing technology, and their reinforced structural characteristics and mechanical properties were evaluated. The results showed that when the reinforced phase volume fraction of Ti2AlC was 20%, three-dimensional interpenetrating network structures were formed in the composites. Above 20%, Ti2AlC phase in the composites accumulated and grew to form thick skeletal networks. The microplastic deformation behavior of Ti2AlC phase, such as kink band and delamination, improved the fracture toughness of the composites. Comparative analysis indicated that the uniform and small interconnecting network structures could further reinforce the composites. The bending strengths of composites prepared with 20 vol.% Ti2AlC reached (900.9±45.0) MPa, which was 25.5% higher than that of TiAl matrix. In general, the co-continuous Ti2AlC/TiAl composite with excellent mechanical properties can be prepared by powder metallurgy method.

We develop a theoretical approach to investigate the impact that nonlocal and finite-size effects have on the dielectric response of plasmonic nanostructures. Through simulations, comprehensive comparisons of the electron energy loss spectroscopy (EELS) and the optical performance are discussed for a gold spherical dimer system in terms of different dielectric models. Our study offers a paradigm of high efficiency compatible dielectric theoretical framework for accounting the metallic nanoparticles behavior combining local, nonlocal and size-dependent effects in broader energy and size ranges. The results of accurate analysis and simulation for these effects unveil the weight and the evolution of both surface and bulk plasmons vibrational mechanisms, which are important for further understanding the electrodynamics properties of structures at the nanoscale. Particularly, our method can be extended to other plasmonic nanostructures where quantum-size or strongly interacting effects are likely to play an important role.

The dynamic parameter model based on cellular automata was not taken into account interaction between pedestrian and environment,it resulted in quite different from that of in real life.So a new model was proposed by taking into account one of the interactions:repulsion.In the present work, evacuation involving repulsion problem was studied in the room with single exit.The expanded model based on dynamic parameter model is introduced by using the quantitative of repulsion.The model could be used to explore the different degree of panic through repulsion.The corresponding simulations of pedestrian evacuation with repulsion were carried out. It extends the constraint where the original model was applied. The improved model is more accordance with actual circumstance than the original dynamic parameters model.The improved model is not only expected to model evacuations in detail but also has high efficiency. Refereed/Peer-reviewed

The oscillator model on nonrelativistic Canonical (soft), Lie-Algebraic deformation noncommutative space and deformed Heisenberg-Weyl Algebra noncomutative phase space are analyzed. For canonical deformation the additional dynamical effects are absent. For two kinds of Lie-Algebraic deformation space the additional effects are generated. Remarkably angular frequency ω ρ is stepfunction, non-periodic function, and contains imaginary frequency. The corresponding particle trajectory varies greatly along with the deformation and time parameter $\hat{k}$ , t. For deformed Heisenberg-Weyl Algebra noncommutative phase space the additional corrections are generated. K ρ ,ω ρ and particle trajectory have constant second-order correction with deformation parameters Θ and Π, but the particle still keep trajectory of classical oscillator.

On the basis of the Landauer-Buttiker scattering formalism and transfer matrix method, we investigated the spin-dependent shot noise in parabolic-well with two ferromagnetic contacts (F/PW/F). The quantum size and Rashba spin-orbit interaction are discussed simultaneously. The results indicate that the shot noise is periodic function of the parabolic-well width. The oscillation frequencies of the shot noise decrease with the increasing of the parabolic-well depth, and increase with the increasing of the Rashba spin-orbit coupling strength. The amplitude and peak to valley ratio of the shot noise are strongly dependent on the magnetization configuration of the junction.

We have investigated theoretically the gas phase reactions of dimethyl sulfoxide (DMSO) with atom Cl in the absence and presence of a single water molecule. The calculations of the potential energy surfaces in the water-free and water-assisted along the different channels are performed at the CCSD(T)/6-311++G(2df,2p)//MP2/6-31G(d) level. The calculated results show that energy barriers of the Hc-abstraction reaction are reduced due to one water molecule added. The computed rate constants of Hc-abstraction reaction indicate that the reaction with water is faster than the value of the naked reaction. However, Ha-abstraction reaction, path2, path3, and path4 are slower without water than hydrous channels.

The gas phase reaction between dimethylsulfide (DMSO) and hydroxyl rad- ical (OH) without and with a single water molecule are investigated employing the quantum chemical calculations at the b3lyp/aug-cc-pvtz and mp2/aug-cc-pvtz levels of theory, respectively. We have been given five paths of OH radical with DMSO (A , B, C, D and E). The geometries and computed energies not only indicate that water molecule produces a catalytic effect for path A and path B, but produces a negative ef- fect for path C, path D and path E. We also give the rate constants to support the above result. We can draw the conclusion that water molecule can influence the reaction process, through forming new molecular compounds.

The initial reactions of HO2 with oxalyl dichloride, oxalyl dibromide, acetyl chloride, and acetyl bromide are studied for the first time using the density functional theory with CAM-B3LYP and wB97XD, CBS-QB3, and G3 theoretical methods and the transition state theory. The reactions occur via the similar mechanism that the prereactive complex is formed before the transition state and product. The calculated results demonstrate that the HO2 radical with ClC(O)C(O)Cl and BrC(O)C(O)Br reactions is feasible and could play a significant role in the atmosphere because the barriers are 0.13 kcal/mol, −0.05 kcal/mol with respect to the free reactants, respectively at the CBS-QB3 level of theory. In addition, the rate constants of the HO2 + ClC(O)C(O)Cl and HO2 + BrC(O)C(O)Br reactions are computed to be 1.37 × 10−15 cm3 mol−1 s−1, 1.70 × 10−15 cm3 mol−1 s−1 at 298 K. However, the HO2 reactions with acetyl chloride and acetyl bromide are of no importance because of higher activated barrier and slower rate constant. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011

To increase the mechanical properties of the metal rollers, Mo and Mo+Y2O3alloy powders were designed. And a kind of coating fabricated by a continuous wave CO2laser surface alloying(LSA) on 40Cr steel roller was obtained. The effect of Mo and Mo+Y2O3on microstructure, hardness and wearing resistance of alloying coating were studied by OM, SEM, XRD, microhardness tester and wearing tester. The experimental results indicate that the grain size in alloying coating is obviously fined, and the grain boundary is strengthened. The uniformity and density of microstructure are improved. The microhardness and wear resistance of alloying coating are significantly increased.

The uncertainty relations are discussed on a noncommutative plane when noncommutativity of momentum spaces is considered. It is possible to construct normalizable states by simultaneously saturating two coordinate-momentum uncertainty relations. However, under the natural condition θη ≪ 4ħ2 one can not construct a normalizable state by simultaneously saturating any other pairs out of four basic nontrivial uncertainty relations.

The entangled state representation has been constructed on noncommutative phase space. Using this appropriate representation, the energy spectrum of general two-dimensional harmonic oscillator has been obtained exactly.

Stimulated emission has been observed from oxide structure of silicon when optically excited by 514 nm laser. The twin peaks in the region from 690 nm to 700 nm are dominated by stimulated emission which can be demonstrated by its threshold behavior and transition in linear evolution. The oxide structure was fabricated by laser irradiation and annealing treatment on silicon. A model for explaining the stimulated emission has been proposed in which the trap states of the interface between oxide of silicon and porous nanocrystal play an important role.

In this work, the Schrodinger equation with the time-dependent potential \(V(z,\hat{p},t)=g_{1}(t)z+g_{2}(t)\hat{p}+g_{3}(t)\) has been solved by the method of time-space transformation in 1+1 dimensions. The corresponding analytical wave function to Schrodinger equation is obtained. In addition, the discussion of solutions to particular cases has been made.

Stimulated emission has been observed from oxide structure of silicon when optically excited by 514 nm laser. The photoluminescence (PL) pulse has a Lorentzian shape with a full width at half maximum (FWHM) of 0.5–0.6 nm. The twin peaks at 694 nm and 692 nm are dominated by stimulated emission which can be demonstrated by its threshold behavior and transition from sub-threshold to linear evolution in light emission. The gain coefficient from the evolution of the peak-emission intensity as a function of the optically pumped sample length has been measured. The oxide structure was fabricated by laser irradiation and annealing treatment on silicon. A model for explaining the stimulated emission has been proposed in which the trap states of the interface between oxide of silicon and porous nanocrystal play an important role.

We proposed a scheme to implement the entanglement swapping based on cavity QED. Using this scheme, we can obtain the entanglement swapping with the success probability of 100% for a two atoms system and a three atoms system respectively, and the entanglement swapping is insensitive to both the cavity decay and thermal field.

Relativistic comparison theorems are established for discrete eigenvalues of Klein–Gordon equation with vector and scalar potentials in d -dimensions. Theorem 1 : If V ( λ ) and S ( λ ) depend on a parameter λ , ∂ S / ∂ λ ⩾ 0 , S ⩾ 0 , ∂ V / ∂ λ ⩾ 0 , V ⩽ 0 , E > 0 , then it follows that ∂ E n / ∂ λ ⩾ 0 . Theorem 2 : If S 2 ⩾ S 1 ⩾ 0 , 0 ⩾ V 2 ⩾ V 1 , E > 0 , then the corresponding eigenvalues are ordered as E n ( 2 ) ⩾ E n ( 1 ) . Theorem 3 : If 0 ⩾ V 2 ⩾ V 1 , S 2 ⩾ | S 1 | , E n ( 1 ) > 0 , E n ( 2 ) > 0 , then E n ( 2 ) ⩾ E n ( 1 ) . Some illustrative examples are given.

It is shown that the Dirac equation for a new equal scalar and vector anharmonic oscillator potentials could be separated into a solvable angular equation and a radial equation. Corresponding exact solutions of bound states for the Dirac equation have been obtained. The angular solutions are the associated-Legendre polynomial and the radial solutions are expressed in terms of the confluent hypergeometric functions. Finally, the energy equation is found from the boundary condition satisfied by the radial wavefunction.

An expanded dynamic parameter model is introduced based on cellular automata. In this model friction is modeled quantitatively. The dynamic parameters including direction parameter and empty parameter are formulated to simplify tactically the process of making decisions for pedestrian evacuation. The pedestrian moving rule is modified by bringing in the conception of friction under high density, corresponding simulations of pedestrian evacuation is carried out. The improved model considers the impact of interactions among pedestrians on the evacuation process. Therefore, it is more accordance with actual circumstance than the original dynamic parameters model. Refereed/Peer-reviewed

The formic acid catalyzed gas-phase reaction between H(2)O and SO(3) and its reverse reaction are respectively investigated by means of quantum chemical calculations at the CCSD(T)//B3LYP/cc-pv(T+d)z and CCSD(T)//MP2/aug-cc-pv(T+d)z levels of theory. Remarkably, the activation energy relative to the reactants for the reaction of H(2)O with SO(3) is lowered through formic acid catalysis from 15.97 kcal mol(-1) to -15.12 and -14.83 kcal mol(-1) for the formed H(2)O⋅⋅⋅SO(3) complex plus HCOOH and the formed H(2)O⋅⋅⋅HCOOH complex plus SO(3), respectively, at the CCSD(T)//MP2/aug-cc-pv(T+d)z level. For the reverse reaction, the energy barrier for decomposition of sulfuric acid is reduced to -3.07 kcal mol(-1) from 35.82 kcal mol(-1) with the aid of formic acid. The results show that formic acid plays a strong catalytic role in facilitating the formation and decomposition of sulfuric acid. The rate constant of the SO(3)+H(2)O reaction with formic acid is 10(5) times greater than that of the corresponding reaction with water dimer. The calculated rate constant for the HCOOH+H(2)SO(4) reaction is about 10(-13) cm(3) molecule(-1) s(-1) in the temperature range 200-280 K. The results of the present investigation show that formic acid plays a crucial role in the cycle between SO(3) and H(2)SO(4) in atmospheric chemistry.

In this paper, the Schrodinger equation of time-dependent potentials has been studied in non- commutative phase space. As an example, the analytical solution of time-dependent harmonic oscillator has been obtained.

A laser-induced plasma in laser-material interaction due to the fact that it is in an extreme state of high-energy concentration is shown to be a powerful tool to perform drilling process to create micro channels in bulk quartz substrates under certain conditions. The plasma was induced by a Q-Switched Nd:YAG laser incident to a quartz substrate after pre-damaged by thermal-induced processing. The channels are of high quality with smooth kerf surface and the dimension of channels can be controlled from around 25 to 140 microns by a software program that interfaces with the laser system. A study of the dependence of drilling rate on the depth of channels provides a straightforward method for controlling the formation of plasma. The process technology, process characterization, and initial test results of the fabricated micro channels are presented in this paper.

This paper reports a novel laser processing technique for making channels in the nano regime. A Nd:YAG laser was used to dry fabricate micro channels (25 /spl mu/m-100 /spl mu/m diameter) in a 1 cm/sup 3/ fused silica substrate by thermal-induced processing. By controlling the locations of these initiating micro channels on a silica cube, 1D-controllable self-connecting nano fractures can be formed as rectangular channels. These nano channels are smooth and with extremely high aspect ratio (/spl sim/10/sup 4/ depth to width ratio). The length of the channels is controlled by the separation of the initiating micro channels. This laser-based nano channel fabrication technique is fast and inexpensive, and with potential applications in capillary electrophoresis and electro-osmosis driven nano-filtration.

A novel process technology was developed to create 3D micro channel systems bounded by solid 3D quartz substrates without damaging the bounding surfaces of the substrate. The process uses a Nd:YAG laser to induce thermal energy or plasma to micromachine channels in substrates which are transparent to Nd:YAG laser wavelength. We have demonstrated that this process is capable of fabricating up 4mm long circular cross-section channels with diameters ranging from 25 to 200 microns. The channel diameter can be controlled by a software program that interfaces with the laser system, thus allowing complete channel systems to be designed on a CAD software and then directly fabricated by a laser system. The process technology, process characterization, and initial test results of the fabricated micro channels are presented in this paper.

A physical model is derived to create a biological cell separator that is based on controlling the entropy in a microfluidic system having conjoined spherical structures. A one-dimensional simplified model of this three-dimensional problem in terms of the corresponding effects of entropy on the Brownian motion of particles is presented. This dynamic mechanism is based on the Langevin equation from statistical thermodynamics and takes advantage of the characteristics of the Fokker-Planck equation. This mechanism can be applied to manipulate biological particles inside a microfluidic system with identical, conjoined, spherical compartments. This theoretical analysis is verified by performing a rapid and a simple technique for separating yeast cells in these conjoined, spherical microfluidic structures. The experimental results basically match with our theoretical model and we further analyze the parameters which can be used to control this separation mechanism. Both numerical simulations and experimental results show that the motion of the particles depends on the geometrical boundary conditions of the microfluidic system and the initial concentration of the diffusing material. This theoretical model can be implemented in future biophysics devices for the optimized design of passive cell sorters.