Painlevé Analysis and Determinant Solutions of a （3＋1）-Dimensional Variable-Coefficient Kadomtsev-Petviashvili Equation in Wronskian and Grammian Form

In this paper, the investigation is focused on a （3＋1）-dimensional variable-coefficient Kadomtsev- Petviashvili （vcKP） equation, which can describe the realistic nonlinear phenomena in the fluid dynamics and plasma in three spatial dimensions. In order to study the integrability property of such an equation, the Painlevé analysis is performed on it. And then, based on the truncated Painlevé expansion, the bilinear form of the （3＋1）-dimensionaJ vcKP equation is obtained under certain coefficients constraint, and its solution in the Wronskian determinant form is constructed and verified by virtue of the Wronskian technique. Besides the Wronskian determinant solution, it is shown that the （3＋1）-dimensional vcKP equation also possesses a solution in the form of the Grammian determinant.     

浅谈高中化学教科书中习题的作用及编制

本文简述了教科书中习题的性质、特点及其作用,并就教科书中习题如何编制问题,谈了一些想法.     

初中生数学高阶思维的结构模型建构及问卷编制

互联网技术的高速发展、全球化进程的持续发酵等时代因素推进了学生对高阶思维的需求,也促使高阶思维能力成为21世纪人才成功的先决条件.通俗来说,高阶思维是完成复杂任务、解决劣构问题的一种重要能力和心理特征,是21世纪的一种高级综合能力[1].数学作为中学教育中的主要科目,是一门极具抽象性、逻辑性的学科,核心素养的倡导要求数...     

Effects of preparation and operation conditions on precipitated iron nickel catalysts for Fischer-Tropsch synthesis

Iron nickel oxide catalysts were prepared using co-precipitation procedure and studied for the conversion of synthesis gas to light olefins. In particular, the effects of a range of preparation variables such as [Fe]/[Ni] molar ratios of the precipitation solution, precipitate aging times, calcination conditions, different supports and loading of optimum support on the structure of catalysts and their catalytic performance for the tested reaction were investigated. It was found that the catalyst containing 40%Fe/60%Ni/40wt%Al2O3, which was aged for 180 min and calcined at 600 ℃ for 6 h was the optimum modified catalyst. The catalytic performance of optimal catalyst has been studied in different operation conditions such as reaction temperatures, H2/CO molar feed ratios and reaction total pressure. Characterization of both precursors and calcined catalysts was carried out by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area measurements, thermal analysis methods such as thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC).     

A Closed-Form Model for Position-Dependent Potential across the Channel in DG-MOSFETs

A closed-form model for electrostatic potential distribution in the direction normal to the channel for double-gate （DG） MOSFETs is presented. The effects of doping （NA for nMOS） and minority carriers both are taken into account for the first time, in solving Poisson＇s equation analytically. Excellent agreement between model-predicted results and numerical device simulation is achieved for a wide range of body thickness, light or high channeldoping, under various bias conditions. This complete closed form for position-dependent potential distribution has wide applications for MOS compact modelling and device design.     

例析习题（试题）编制中的科学性问题

结合具体案例分析了高中物理习题（试题）编制中存在的表述不恰当、数据不合理、设计不严谨、模型不正确、与实际不符等典型科学性问题,并总结出科学命题的几点启示．     

《精细化工配方常用原料手册》

侯滨滨主编杜晓雪、张浩副主编本书列举了精细化工配方中常用的原料954余种,主要涉及无机、有机、高分子、有机溶剂、工业填料、化学助剂等种类。用其可以混配出数以千计的各种精细化学品。书中每个品种以表格形式总结其物化性质、安全性、应用性能、生产方法及质量指标。可供精细化工及应用领域如食品、化妆品、洗涤剂、皮革、造纸、金属加工、石油加工、环保卫生等从业人员参考。     

巧查星期几

现在的周末假日,是连同"星期记日法"从西方引进的,它最初形成的时候,人们只知道天上有金、木、水、火、土五颗大行星,加上太阳、月亮,总共是七个重要天体,所以把一星期定为七天,每天对应一个天体,要是早知道太阳系有九大行星,大概一星期就要长达十一天     

半导体超晶格国家重点实验室诚聘英才

中国科学院半导体研究所半导体超晶格国家重点实验室是以半导体物理研究为主的国家重点实验室,在半导体材料生长、器件加工、物理测试和理论研究方面有着非常雄厚的研究基础,20年来为我国在半导体领域的基础研究方面做出了突出的贡献。现计划在半导体自旋电子学、半导体材料与器件物理以及固态量子信息方面招聘人才,研究职位包括固定编制人员、项目聘用人员和博士后。一、招聘岗位(一)科研人才从事半导体自旋电子学、半导体材料与器件物理和固态量子信息方面的科学研究,特别是实验方面的研究工作。