基于数据挖掘建立高校系科办学评估体系的合理性评价系统

本文运用关联规则发现方法与人事信息库进行数据挖掘,寻找高校系科办学评估体系中各因素间的关联关系,并根据关联关系强弱分析各因素的权重设置的合理性。本文分析和指出了现有一些看法的优缺点,提出了在Tid-optim算法,并对发现的规则进行分析,通过数据抽样建立合理性评价体系,有效地解决了权重设置的不合理问题,为高校管理决策提供科学依据。     

复变量重构核粒子法与有限元法耦合解弹性力学问题

提出了弹性力学的复变量重构核粒子法与有限元法的耦合法(CVRKPM/FEM).采用场量耦合试函数法将弹性力学的复变量重构核粒子法与有限元法进行耦合,详细推导了在整个求解域上的耦合公式.最后通过数值算例证实了本文所提弹性力学的复变量重构核粒子法与有限元的耦合法的有效性.本文的耦合法不仅可以很方便地施加本质边界条件,而且可以充分利用无网格方法和有限元法的优势,弥补各自不足以提高计算效率.     

Estimating topological charge of propagating vortex from single-shot non-imaged speckle

Encoding information using the topological charge of vortex beams has been proposed for optical communications. The conservation of the topological charge on propagation and the detection of the topological charge by a receiver are significant in these applications and have been well established in free-space. However, when vortex beams enter a diffuser,the wavefront is distorted, leading to a challenge in the conservation and detection of the topological charge. Here, we present a technique to measure the value of the topological charge of a vortex beam obscured in the randomly scattered light. The results of the numerical simulations and experiments are presented and are in good agreement. In particular, only a single-shot measurement is required to detect the topological charge of vortex beams, indicating that the method is applicable to a dynamic diffuser.     

对流传热边界层温度分布的激光干涉测量

本文介绍利用双镜干涉仪测量对流传热边界层中二维温度分布的方法。当冷空气流经热板模型时,附面层内的干涉条纹发生弯曲。根据条纹弯曲偏移量,由折射率与温度的关系,画出空气温度的二维分布图。整个过程由光学方法及微计算机全盘处理,是一种无接触测量方法。     

管式PECVD氮化硅薄膜不同退火环境的工艺研究

研究了在真空与氮气两种环境中不同的退火温度和退火时间对氮化膜薄膜性能影响,测试了退火后氮化硅薄膜的膜厚、折射率、少子寿命以及电性能参数.结果表明,多晶硅管式PECVD真空退火环境优于氮气,并确定当退火温度在450 ℃、退火时间20 min时,工艺参数最佳.当温度过高过低均不利于膜厚的增加也不利于形成良好的欧姆接触,且此时光电转换效率较差.折射率的变化却不同,其最大值是在低温下达到的,此时氮气环境更有利于高折射率的获得.此外,还就膜厚和折射率随温度、环境变化的情况进行了详细的讨论.     

脂肪族二酸二烷基双去氢枞基双噁二唑的合成及除草活性

以去氢枞酸为原料,制备去氢枞酸酰氯.以脂肪族二酸为原料,经过脂肪族二酸二乙酯得到脂肪族二酸二酰肼.脂肪族二酸二酰肼与去氧枞酸酰氯在相转移催化下反应得到N,N＇-二去氢枞酰基取代脂肪族二酸二酰肼,再脱水环合,得到5个标题化合物脂肪族二酸二烷基双去氢枞基双噁二唑.通过元素分析,IR,MS,1H NMR和13C NMR对所合成的新化合物进行了结构表征.初步的除草活性测试表明,化合物6b～6e在100 μg/mL浓度下对油菜的胚根生长具有良好的抑制作用,抑制率均超过80％.     

Eu离子价态对Sr_2MgSi_2O_7:Eu发光特性的影响(英文)

分别在空气、还原气体、再空气、最后再在还原气体等气氛中通过四个步骤合成了Sr1.99MgSi2O7:Eu0.01.在空气中合成的样品呈现出Eu2+和Eu3+两种价态的发光特征峰,而在还原气体中合成的样品,只呈现出Eu2+一种价态的特征发光峰,并且有长余辉和两个热致发光带.但若样品直接在还原气氛下合成,则只呈现一个热致发光带.样品在空气中合成产生空穴陷阱,此陷阱在还原合成气氛下仍被保留,并与还原气体合成条件下产生的电子陷阱有所区别,最终导致两个热致发光带.     

溶剂热法制备ATO纳米球及其性能研究

以五水四氯化锡和三氯化锑为主要原料,以乙二醇为溶剂,采用溶剂热法合成了锑掺杂氧化锡(ATO)纳米球。用X射线衍射仪和透射电子显微镜对合成的ATO纳米球进行结构表征,用紫外可见分光光度计和低阻抗表面阻抗仪研究其光电性能。结果表明：所合成的ATO均为四方晶型结构,由粒径为5~10 nm的ATO纳米晶聚集成直径为80~120 nm的纳米球,且分散性良好。Sb³⁺掺杂量对ATO纳米球的光、电性能有很大影响,随着Sb³⁺掺杂量的增加其可见光透过率和电导率都呈现先增大后减小的变化关系。在n_Sb/n_Sn比为9∶100时其光电性能达到最佳。     

Combining the complex variable reproducing kernel particle method and the finite element method for solving transient heat conduction problems

In this paper, the complex variable reproducing kernel particle (CVRKP) method and the finite element (FE) method are combined as the CVRKP-FE method to solve transient heat conduction problems. The CVRKP-FE method not only conveniently imposes the essential boundary conditions, but also exploits the advantages of the individual methods while avoiding their disadvantages, then the computational efficiency is higher. A hybrid approximation function is applied to combine the CVRKP method with the FE method, and the traditional difference method for two-point boundary value problems is selected as the time discretization scheme. The corresponding formulations of the CVRKP-FE method are presented in detail. Several selected numerical examples of the transient heat conduction problems are presented to illustrate the performance of the CVRKP-FE method.     

First-principles study of hydrogen adsorption on titanium-decorated single-layer and bilayer graphenes

The adsorption of hydrogen molecules on titanium-decorated （Ti-decorated） single-layer and bilayer graphenes is studied using density functional theory （DFT） with the relativistic effect. Both the local density approximation （LDA） and the generalized gradient approximation （GGA） are used for obtaining the region of the adsorption energy of H2 molecules on Ti-decorated graphene. We find that a graphene layer with titanium （Ti） atoms adsorbed on both sides can store hydrogen up to 9.51 wt% with average adsorption energy in a range from -0.170 eV to 0.518 eV. Based on the adsorption energy criterion, we find that chemisorption is predominant for H2 molecules when the concentration of H2 molecules absorbed is low while physisorption is predominant when the concentration is high. The computation results for the bilayer graphene decorated with Ti atoms show that the lower carbon layer makes no contribution to hydrogen adsorption.