n维简并理想费米气体的化学势和热容量

本文对能谱为ε =aps 的n维简并理想费米气体作了统一讨论 ,给出了它的一级近似下的费米能 ,有限温度下的化学势、内能以及热容量的表达式。

关于体育运动中的体势语研究

体势语是研究人们在社会活动交往过程中所表达出的能被人们认识和理解的非语言信号。体育运动是一种社会现象,那么,体势语也同样地反映到社会现象之一的体育运动中。人们从事体育活动时,通过特定的体势语来指导和管理学校体育教学、运动训练、体育竞赛、体育竞赛管理等。为此,本文就体势语在体育运动中的作用和意义进行了粗浅的研究,阐明了体势语在体育运动中的用途,提出了“体育体势语”这一概念,探讨了建立体育体势语学科的可能性,并还就其研究内容、研究对象和方法进行了初步研究。

非语言交际在教学中的应用

文章主要论述非语言交际研究中的四个方面:非语言交际与语言交际,非语言交际研究的主要课题,非语言交际与跨文化交际,非语言交际与外语教学。通过深入研究非语言交际的各个方面,将有助于我们正确认识非语言交际在教学中的作用,从而提高教学效果。

The Bipolar Theory of the Field-Effect Transistor:X.The Fundamental Physics and Theory(All Device Structures)

This paper describes the foundation underlying the device physics and theory of the semiconductor field effect transistor which is applicable to any devices with two carrier species in an electric field. The importance of the boundary conditions on the device current-voltage characteristics is discussed. An illustration is given of the transfer DCIV characteristics computed for two boundary conditions,one on electrical potential,giving much higher drift-limited parabolic current through the intrinsic transistor, and the other on the electrochemical potentials, giving much lower injection-over-thebarrier diffusion-limited current with ideal 60mV per decade exponential subthreshold roll-off, simulating electron and hole contacts. The two-MOS-gates on thin pure-body silicon field-effect transistor is used as examples

Structures and Dynamics of a Two-Dimensional Confined Dusty Plasma System

The influence of the confining potential strength and temperature on the structures and dynamics of a two-dimensional (2D) dusty plasma system is investigated through molecular dynamic (MD) simulation. The circular symmetric confining potential leads to the nonuniform packing of particles, that is, an inner core with a hexagon lattice surrounded by a few outer circular shells. Under the appropriate confining potential and temperature, the particle trajectories on middle shells form a series of concentric and nested hexagons due to tangential movements of particles.Mean square displacement, self-diffusion constant, pair correlation function, and the nearest bond are used to characterize the structural and dynamical properties of the system. With the increase of the confining potential, the radial and tangential movements of particles have different behaviors. With the increase of temperature, the radial and tangential motions strengthen, particle trajectories gradually become disordered, and the system gradually changes from a crystal or liquid state to a gas state.

Molecular Thermodynamics of Charged Hard-Dumbbell Fluids

Chemical potentials of charged hard-dumbbell fluids are obtained by Monte Carlo simulations using Widom's test-particle method, corresponding compressibility factors are achieved by integration of chemical potentials at different densities. A molecular thermodynamic model is also developed for these charged hard-dumbbell fluids where the residual Helmholtz function is composed of two terms: a reference term responsible for the charged hard spheres and a bonding contribution measuring the sticky interactions between positive and negative hard ions.Model predictions are in good agreement with simulation results.

Wave Drift Forces on Two Floating Bodies Arranged Side by Side

An innovative hydrodynamic theory and numerical model were developed to help improve the efficiency, accuracy, and convergence of the numerical prediction of wave drift forces on two side-by-side deepwater floating bodies. The wave drift forces were expressed by the double integration of source strength and the corresponding Green function on the body surface, which is consistent with the far field formula based on momentum conservation and sharing the advantage of near field calculations providing the drift force on each body. Numerical results were validated through comparing the general far field model and pressure integral model, as well as the middle field model developed usin^z the software HydroStar.

Numerical simulation of an algal bloom in Dianshan Lake

A hydrodynamic model and an aquatic ecology model of Dianshan Lake,Shanghai,were built using a hydrodynamic simulation module and the water quality simulation module of Delft3D,which is an integrated modelling suite offered by Deltares. The simulated water elevation,current velocity,and direction were validated with observed data to ensure the reliability of hydrodynamic model. The seasonal growth of different algae was analyzed with consideration of observed and historical data,as well as simulated results. In 2008,the dominant algae in Dianshan Lake was Bacillariophyta from February to March,while it was Chlorophyta from April to May,and Cyanophyta from July to August. In summer,the biomass of Cyanophyta grew quickly,reaching levels much higher than the peaks of Bacillariophyta and Chlorophyta. Algae blooms primarily occurred in the stagnation regions. This phenomenon indicates that water residence time can influence algal growth significantly. A longer water residence time was associated with higher algal growth. Two conclusions were drawn from several simulations: reducing the nutrients inflow had little effect on algal blooms in Dianshan Lake; however,increasing the discharge into Dianshan Lake could change the flow field characteristic and narrow the range of stagnation regions,resulting in inhibition of algal aggregation and propagation and a subsequent reduction in areas of high concentration algae.

Study of Thermodynamics of Liquid Noble-Metals Alloys Through a Pseudopotential Theory

The Gibbs-Bogoliubov （GB） inequality is applied to investigate the thermodynamic properties of some equiatomic noble metal alloys in liquid phase such as Au-Cu, Ag-Cu, and Ag-Au using well recognized pseudopotential formalism. For description of the structure, well known Percus-Yevick （PY） hard sphere model is used as a reference system. By applying a variation method the best hard core diameters have been found which correspond to minimum free energy. With this procedure the thermodynamic properties such as entropy and heat of mixing have been computed. The influence of local field correction function viz; Hartree （H）, Taylor （T）, lehimaru-Utsumi （IU）, Farid et al. （F）, and Sarkar et al. （S） is also investigated. The computed results of the excess entropy compares favourably in the case of liquid alloys while the agreement with experiment is poor in the case of heats of mixing. This may be due to the sensitivity of the heats of mixing with the potential parameters and the dielectric function.

In the Name of ESP Comments on the Recent Discussion on College English Teaching Reform in China

One of the most controversial debate topics in current College English teaching is whether EGP （English for General Purposes） should be replaced by ESP （English for Specific Purposes）. The latest College English Curriculum issued by MOE （Ministry of Education） does not reflect the trend of developing College English Teaching by focusing on ESP, but rather on improving general English course books. However, the first local College English Curriculum published in 2012 in Shanghai focuses on developing ESP and English for academic purpose as its teaching objectives. This paper analyzes different definitions of ESP in China＇s education setting, compares different views on handling the relationship between EGP and ESP in China＇s College English Reform, and explores how to apply an appropriate notion of EGP to College English teaching in China.

Numerical simulation of leading edge cavitation within the whole flow passage of a centrifugal pump

In this paper, the periodically unsteady pressure field and head-drop phenomenon caused by leading edge cavitation have been investigated numerically by computational fluid dynamics （CFD） in a single stage centrifugal pump. A CFD model for cavita- tion steady and unsteady simulation has been calculated using the κ-ω SST turbulence model combining with a multiphase ap- proach, based on a homogeneous model assumption. A truncated form of Rayleigh-Plesset equation is used as a source term for the inter-phase mass transfer. The CFD computational region includes the suction cone, impeller, side chambers and volute, as well as suction and pressure pipes. The results were compared with experimental data under non-cavitation and cavitation conditions and a good agreement was obtained for the global performance, the experimental data of the head and the efficiency are 34.04 m and 74.42% at BEP, respectively, the predicted head is 34.31 m and the predicted efficiency is 73.75%. The analy- sis of inner flow pattern shows that the vortex flow generation in the rear of cavity region is the main reason of the head-drop. Obvious increasing can be observed for the amplitude of the pressure fluctuation at the blade passing frequency with different cavitation situations, and subpeak can be found. Besides, the effects of unsteady flow in the side chambers cannot be neglected for accurately predicting the inner flow of the pump. These results imply that this numerical method is suitable for the cavitat- ing flow in the pump.

Self-trapping and Macroscopic Tunnelling of Superfluid Fermi Gases in Multi-well Potentials

We study the tunnelling dynamics of superfluid Fermi gases trapped in multi-well system along the BEC-BCS crossover. Within the hydrodynamical model and by using the multi-mode approximation, the self-trapping dynamics of superfluid Fermi gases in multi-well system are obtained numerically. We find that the self-trapping to diffusion transition strongly depends on the well number. When the well number is less than three, the self-trapped state takes place easier on the BEC side than that on the BCS side. However, when the well number is larger than three, the self-trapped state takes place easier on the BCS side instead of the BEC side. Furthermore, by considering a superfluid of 40K atoms, we obtain the zero-mode and π-mode Josephson frequencies of coherent atomic oscillations in double-well system. It is noteworthy that the Josephson mode, especially, the existence of π-mode frequency strongly depends on the atoms number on the BCS side.

Theoretical study of the low-lying electronic excited states for molecular aggregates

We present here a brief summary of a National Natural Science Foundation Major Project entitled "Theoretical study of the low-lying electronic excited state for molecular aggregates". The project focuses on theoretical investigation of the electronic structures and dynamic processes upon photo-and electric-excitation for molecules and aggregates. We aim to develop reliable methodology to predict the optoelectronic properties of molecular materials related to the electronic excitations and to apply in the experiments. We identify two essential scientific challenges: (i) nature of intramolecular and intermolecular electronic excited states; (ii) theoretical description of the dynamic processes of the coupled motion of electronic excitations and nucleus. We propose the following four subjects of research: (i) linear scaling time-dependent density-functional theory and its application to open shell system; (ii) computational method development of electronic excited state for molecular aggregates; (iii) theoretical investigation of the time evolution of the excited state dynamics; (iv) methods to predict the optoelectronic properties starting from electronic excited state investigation for organic materials and experimental verifications.

The influence of mitochondria in epigenetics revealed through naturally occurring fish cybrids

Epigenetic processes are important mechanisms for phenotypic changes that occur in response to the environment. As such, it is expected that the alteration of cytoplasmic composition （the immediate environment of nuclei） results in the modifica- tion of the methylome and the expression of the nuclear genome. Cytoplasmic hybrids （or cybrids） are an ideal model to study the influence of mitochondria on gene expression. In this study, we take advantage of the natural of two biotypes that have a similar nuclear genome type Chrosomus eos, but harbor mitochondria from different species （C. eos in wild type or C. neogaeus in cybrids） to assess the effects of mitochondria on DNA methylation profiles and protein expression of the nuclear ge- nome. Comparison between these biotypes is particularly relevant given their recent divergence and their low level of genetic dif- ferentiation. Variations of DNA methylation assessed on tissues from different embryonic origins revealed the distinct profiles of cybrid and wild type populations. Differences are more pronounced between wild type and cybrids than between populations of a given biotype. The proteome is also more different between biotypes than within a given biotype. These results indicate a strong influence of mitochondria on the nuclear genome, which remains detectable in different genetic and environmental contexts. These changes in the methylome and proteome of cybrids are expected to reflect the adjustments imposed by the coexistence of nuclear and mitochondrial genomes from different species [Current Zoology 58 （1）： 138-145, 2012].