混煤煤灰熔融特性及矿物质形态的研究

本文对混煤熔融特性温度进行测定，并利用X-射线衍射分析对混煤煤灰的矿物组成进行试验分析，结果表明：混煤可改变原煤的结渣程度；混煤灰熔点与混煤比不成线性关系变化是混煤煤灰的低温共熔现象所致；在变形温度T1下煤灰中矿物质莫来石对煤灰熔融特性温度影响较大，莫来石含量越高，灰熔点越高．     

Study of the Binding Energy of Relativistic Nuclear Matter in the Relativistic σ-ω-π Model

A relativistic σ-ω-π model is proposed to calculate the binding energy of relativistic nuclear matter. We put emphasis on the relativistic particle-hole, delta-hole excitation of pion propagator in nuclear matter. The renormalization of the nucleon self-energy in nuclear matter is made for the pseudo-vector πNN and πNΔ couplings by introducing corresponding form factor and by dispersion relation. We find that the density dependence correction to meson-NN coupling constants is very important to saturate the binding energy of nuclear matter. The density dependence correction to πNN and πNΔ coupling constants has the effect of softening the EOS of nuclear matter.     

非对称耦合量子阱中亚毫米波辐射及其带间激子复合发光特性的理论研究

基于V形三能级模型运用密度矩阵方程研究了非对称耦合量子阱退局域化现象，并具体分析了导带中电子作阱间振荡所产生的亚毫米辐射和激子复合所产生的近红外发射物理过程.理论结果表明：阱间电子波包振荡等效为一经典阻尼振子，其寿命由载流子与纵向光学声子散射时间和电子穿过势垒的渡越时间决定，所产生的亚毫米波辐射强度衰减仅与阱间阻尼系数有关，其线性服从洛仑兹分布.由带间激子复合所产生的近红外辐射频率随电子阱间振荡频率增加而减小，表现为量子限域斯塔克红移，即非对称量子阱在近红外发光区特性随反向偏压而变.这一结果预示着耦合量子 关键词： 非对称耦合量子阱 电子波包振荡 亚毫米波辐射 近红外发射     

Exact Solution of a Cellular Automaton for Traffic

We present an exact solution of a probabilistic cellular automaton for traffic with open boundary conditions, e.g., cars can enter and leave a part of a highway with certain probabilities. The model studied is the asymmetric exclusion process (ASEP) with simultaneous updating of all sites. It is equivalent to a special case (v _max=1) of the Nagel–Schreckenberg model for highway traffic, which has found many applications in real-time traffic simulations. The simultaneous updating induces additional strong short-range correlations compared to other updating schemes. The stationary state is written in terms of a matrix product solution. The corresponding algebra, which expresses a system-size recursion relation for the weights of the configurations, is quartic, in contrast to previous cases, in which the algebra is quadratic. We derive the phase diagram and compute various properties such as density profiles, two-point functions, and the fluctuations in the number of particles (cars) in the system. The current and the density profiles can be mapped onto the ASEP with other time-discrete updating procedures. Through use of this mapping, our results also give new results for these models.     

SU(3)L × U(l)X Model and N-Particle as Dark Matter Particle

We proposed an SU(3)_L × U(l)_X gauge model for the electroweak interactions. In the model each lepton family contains two neutral particles. We show that the new neutral lepton (N-particle) can play the role of dark matter particle.     

土壤水分去除算法的田间原位光谱反演棉田有机质

田间原位可见-近红外光谱(VIS-NIR)能够有效的提高土壤属性的检测效率,但由于原位土壤中水分因素的影响,土壤属性的预测精度很难达到预期。如何有效去除土壤中的水分对土壤其他属性光谱预测的影响,是利用田间原位光谱高精度预测土壤属性所面临的难题,也是土壤光谱技术由室内转向田间的突破口。该问题的有效解决,可减除土壤样品的采集与室内预处理等过程,实现土壤属性的田间原位光谱测定。以新疆南部地区阿拉尔垦区十二团棉田为研究区,采用网格采样法共采集了116个0～20 cm深度的表层土壤样品,剔除1个异常值样品,得到115个有用样品,利用SR-3500型便携式地物光谱仪采集了231个样点的田间原位光谱数据,土样经风干、研磨和过筛等处理后测定其室内光谱和有机质含量。利用Kennard-Stone算法将115个土样分为69个转换子集及46个预测集,采用外部参数正交化法(EPO)、光谱直接转换法(DS)及光谱间接转换法(PDS)三种去除水分算法结合原位光谱反射率(R)、反射率一阶微分(R′)、反射率对数(LOG(R))以及反射率倒数(1/R)四种数学变换方式,运用随机森林(RF)模型进行不同组合模型的构建及精度评价。结果表明：(1)土壤有机质含量越高,土壤光谱反射率越低。土壤田间原位光谱反射率低于土壤室内光谱反射率;(2)室内光谱反射率与土壤有机质含量之间的相关性大于田间原位光谱,室内光谱经一阶微分变换后与土壤有机质含量之间的相关性显著提升。(3)土壤室内光谱反射率模型预测精度(R2=0.86, RPD=2.08, RMSE=1.55 g·kg-1, MAPE= 0.14)高于田间原位光谱反射率模型(R2=0.71, RPD=1.49, RMSE=2.17 g·kg-1, MAPE=0.20)。在去除水分算法模型中,以EPO一阶微分模型去除水分效果最好,决定系数R2由0.71提高到0.83,RPD由1.49提高到2.04,RMSE由2.17 g·kg-1降低至1.58 g·kg-1,MAPE由0.20降低至0.14。本研究实现了去除土壤水分因素的影响,提高了田间原位光谱预测土壤有机质的精度,为南疆棉田大尺度土壤有机质的预测及土壤肥力的评价提供了重要的参考。     

Phase structures of neutral dense quark matter and applicationto strange stars

In the contact interaction model,the quark propagator has only one solution,namely,the chiral symmetry breaking solution,at vanishing temperature and density in the case of physical quark mass.We generalize the condensate feedback onto the coupling strength from the 2 flavor case to the 2+1 flavor case,and find the Wigner solution appears in some regions,which enables us to tackle chiral phase transition as two-phase coexistences.At finite chemical potential,we analyze the chiral phase transition in the conditions of electric charge neutrality andβequilibrium.The four chemical potentials,μ_u,μ_d,μ_s and He,are constrained by three conditions,so that one inde-pendent variable remains:we choose the average quark chemical potential as the free variable.All quark masses and number densities suffer discontinuities at the phase transition point.The strange quarks appear after the phase trans-ition since the system needg more energy to produce a d.-quark than an s-quark.Taking the EOS as an input,the TOV equations are solved numerically,and we show that the mass--radius relation is sensitive to the EOS.The max-imum mass of strange quark stars is not susceptible to the parameter Aq we introduced.     

基于面跳跃方法的半导体纳米材料从头算非绝热分子动力学研究

在光电子学应用中,器件性能主要取决于半导体纳米材料中的光生载流子动力学过程. 但是,受反应速率、材料表面积、材料组成等多种因素影响,描述其中的动力学过程非常具有挑战性. 模拟光生载流子动力学过程可以通过绝热分子动力学方法实现,即求解包含非绝热耦合项的含时薛定谔方程. 在众多绝热分子动力学方法中,面跳跃方法出色地平衡了计算精度和计算成本,因而成为描述半导体纳米材料中不同非绝热过程间竞争的有力工具,已被用来模拟材料中的超快动力学过程和其他复杂效应,如Janus过渡金属二硫族化合物范德华异质结中的电荷分离. 本综述通过介绍该领域代表性的理论及实验工作,阐述了光生载流子对半导体纳米材料性能的重要影响,以及面跳跃方法在描述其动力学行为中的重要作用. 由于日趋复杂的材料体系对理论工作提出了巨大的挑战,本综述重点介绍了最近用于模拟这些复杂材料的一些开创性的新方法,包括高精度的电子结构方法和与之相结合的绝热分子动力学方法.     

Active thermophoresis and diffusiophoresis

Thermophoresis and diffusiophoresis respectively refer to the directed drift of suspended particles in solutions with external thermal and chemical gradients, which have been widely used in the manipulation of mesoscopic particles. We here study a phoretic-like motion of a passive colloidal particle immersed in inhomogeneous active baths, where the thermal and chemical gradients are replaced separately by activity and concentration gradients of the active particles. By performing simulations, we show that the passive colloidal particle experiences phoretic-like forces that originate from its interactions with the inhomogeneous active fluid, and thus drifts along the gradient field, leading to an accumulation. The results are similar to the traditional phoretic effects occurring in passive colloidal suspensions, implying that the concepts of thermophoresis and diffusiophoresis could be generalized into active baths.     

基于F-W暗物质模型的暗物质探测仪的设计思路

按F-W暗物质模型,暗物质之间有相互作用,能够形成暗天体.飞临地球的小暗天体会对已知物体有微引力效应.由此提出了暗物质小天体探测仪的设计原理,定量计算了飞临地球的暗天体通过探测仪时导致的力矩变化.