鄱阳湖三维水质模拟软件设计与仿真

随着鄱阳湖生态经济区建设的推进,鄱阳湖水环境保护问题引起了各方高度关注。通过建立水质数学模型,用计算机进行模型求解、模拟和预测,以及设计相应的水质模拟仿真软件来进行水污染扩散仿真,是水污染控制和水环境管理的有效手段。鉴于国外三维水质数据模拟软件价格高、使用受限以及鄱阳湖三维水质数据模拟的特定应用研究需求,利用软件工程的结构化方法和图形可视化技术,设计了一个面向鄱阳湖三维水质数据模拟和分析的软件工具WSAT/H3D-PYH。通过使用该软件进行BOD和DO扩散模拟和趋势预测实验表明,软件具有较好的预测精度,并能以可视化形式直观分析和预测未来一段时间湖区水质浓度的变化趋势。此外,软件还可对局部点污染源扩散进行动态模拟,以便于对突发污染事件可能造成的后果进行提前的估计,为后续治理方案措施的制定提供很好的依据。     

赣南新塘萤石矿区地下水元素钙氟变化及其成矿意义

对新塘脉状矿床及其附近地下水的钙、氟元素进行了系统检测,发现钙、氟含量存在明显的空间分布差异。采矿矿床及其附近地下水的钙、氟含量偏高,而2km远的地下水钙、氟含量低且接近流域平均值,两处平均含量相差近10倍。钙、氟的相关性分析显示,水体中钙、氟含量具有很好的相关性,揭示该区萤石矿成矿受沉积物钙氟控制,并与地下水运动密切相关,通过热液循环不断淋滤溶蚀围岩获取钙氟形成萤石矿。由此,矿区的钙氟异常变化可以作为找矿的重要指标。     

宁波市中小学生视力不良状况调查

为了解宁波市中小学生视力不良的发生率,以2010年浙江省学生体质调研数据为基础,对宁波市3085名中小学生视力进行了调查研究.结果表明:宁波市中小学生视力不良检出率为69.9%,其中男生为69.0%,女生为70.8%;城市学生视力不良检出率为71.2%,乡村学生为68.6%,可见城市学生的视力不良检出率高于乡村学生,并存在统计学意义(P<0.05);但这种城乡差异和2005年学生体质调研中得到的数据相比较,呈现弱化趋势;视力不良的检出率已不再有性别差异;在低年龄段和轻度视力不良程度内,视力不良检出率随年龄的增长突增期提前,中学学段是学生视力不良重灾区,同年龄段视力不良的检出率远超过2005年调查数据.     

岩体动力变形破坏的层次特性(英文)

岩体具有复杂的内部结构,内部结构对于岩土的力学性质具有决定性的影响.文章从岩体结构层次的角度研究了岩体的动力变形与破坏过程,在松弛模型的框架内研究了变形破坏的空间尺度与应变率之间的关系.讨论了裂纹传播速度与荷载强度之间的关系,研究了岩体变形破坏的层次特性.最后从岩体结构层次角度研究了岩体的破坏准则.研究表明:岩体的动力变形与破坏具有层次特性,这一层次特性依赖于外载的空间与时间特性、岩体的结构层次和岩体变形与破坏过程速度的有限性.时间准则与极限变形准则可以较好地描述岩体的动力破坏.     

Energy-efficient beamforming optimization for MISO communication based on reconfigurable intelligent surface

Reconfigurable intelligent surface (RIS), a planar metasurface consisting of a large number of low-cost reflecting elements, has received much attention due to its ability to improve both the spectrum and energy efficiency (EE) by reconfiguring the wireless propagation environment. In this paper, we propose a base station (BS) beamforming and RIS phase shift optimization technique that maximizes the EE of a RIS-aided multiple-input–single-output system. In particular, considering the system circuits’ energy consumption, an EE maximization problem is formulated by jointly optimizing the active beamforming at the BS and the passive beamforming at the RIS, under the constraints of each user’ rate requirement, the BS’s maximal transmit power budget and unit-modulus constraint of the RIS phase shifts. Due to the coupling of optimization variables, this problem is a complex non-convex optimization problem, and it is challenging to solve it directly. To overcome this obstacle, we divide the problem into active and passive beamforming optimization subproblems. For the first subproblem, the active beamforming is given by the maximum ratio transmission optimal strategy. For the second subproblem, the optimal phase shift matrix at the RIS is obtained by exploiting sine cosine algorithm (SCA). Moreover, for this case where each reflection element’s working state is controlled by a circuit switch, each reflection element’s switch value is optimized with the aid of particle swarm optimization algorithm. Finally, numerical results verify the effectiveness of our proposed algorithm compared to other algorithms.     

Landau damping of ion-acoustic waves with simultaneous effects of non-extensivity and non-thermality in the presence of hybrid Cairns-Tsallis distributed electrons

The dispersion properties and Landau damping rate of ion-acoustic waves (IAWs) with the hybrid Cairns-Tsallis distributed (CTD) electrons and Maxwellian ions are investigated using the plasma kinetic model based on Vlasov-Poisson's equations. For both super-extensive (q < 1) and sub-extensive (q > 1) plasmas, the dielectric response function, real frequency, and Landau damping rate of IAWs are derived. By taking the effect of θ_{i, e} (ion-to-electron temperature ratio) into account, it is found that with the increase of ion temperature, the real frequency and wave dispersion effects increase as well (for both super-extensive and sub-extensive cases). Exploring the properties of the Landau damping rate of IAWs with the simultaneous presence of non-thermal parameter α and non-extensive parameter q, a comparison of numerical and analytical results is presented. It is found that in different ranges of θ_{e, i} (electron-to-ion temperature ratio), on decreasing the values of the non-extensive parameter and increasing values of the non-thermal parameter, the weak damping rate is observed (vice versa) in super-extensive or super-thermal plasma, although the trend of the damping rate in sub-thermal plasma is similar (as in the case of super-thermal plasma) but is less weak. It is further revealed that the damping rate of IAWs in thermal plasmas (Maxwellian) is stronger than the damping rate of IAWs in the case of non-thermal plasmas (CTD). The current study is applicable to provide deep insight and further allow the exploration of electrostatic plasma modes in different space and laboratory plasma environments where the hybrid CTD plasma exists.     

Random walks on inhomogeneous lattices

For lattices with two kinds of points (black and white), distributed according to a translation-invariant joint probability distribution, we study statistical properties of the sequence of consecutive colors encountered by a random walker moving through the lattice. The probability distribution for the single steps of the walk is considered to be independent of the colors of the points. Several exact results are presented which are valid in any number of dimensions and for arbitrary probability distributions for the coloring of the points and the steps of the walk. They are used to derive a few general properties of random walks on lattices containing traps.Presented at the Symposium on Random Walks, Gaithersburg, MD, June 1982.     

不同负冲角工况下透平叶栅二次流的数值模拟及分析

本文应用TVD格式和Baldwin－Lomax代数紊流模型求解三维NS方程，对一个透平直列叶栅流场在两个不同的负冲角工况下进行了数值模拟，给出了叶栅马蹄涡及其分离鞍点、通道涡、角涡等二次流涡系的结构及其产生发展过程，并对不同工况下的涡系结构及冲角的影响作了详细的分析和比较．本文结果有助于对叶栅二次流涡系结构的产生发展机制的深入了解，同时表明所用数值求解技术有较高的精度和分辨率。     

Spectral action and big desert

The values of the Higgs mass are obtained for two possibilities of extending the standard model in a way compatible with the existence of a noncommutative structure at high energies. We assume the existence of a big desert between the low energy electroweak scale and the high energy scale Λ=1.1×10¹⁷ GeV, where noncommutative features become relevant. We conclude that it is extremely difficult to depart from the Higgs mass value obtained from noncommutative geometry for the standard model with three generations only.     

AuZn和AuAl分子基态与低激发态的势能函数与热力学性质

用密度泛函理论B3LYP方法计算研究AuZn和AuAl分子基态与低激发态的结构与势能函数,导出分子的光谱数据.结果表明,AuZn和AuAl分子基态分别为X²Σ和X¹Σ,基态与低激发态的势能函数均可用Murrell-Sorbie函数来表达.AuZn分子低激发态a⁴Σ的绝热激发能为43529kJ/mol,AuAl分子低激发态a³Σ的绝热激发能为19991kJ/mol.计算固体AuZn和AuAl的内能和熵时,近似以气体分子的电子能和振动能代替固体分子的内能,用电子熵和振动熵代替固体分子的熵.在此近似下,计算得到AuZn和AuAl基态与低激发态固态分子生成反应热力学性质与温度的关系. 关键词： AuZn和AuAl B3LYP 热力学性质 势能函数