金属-有机框架衍生的多功能光催化剂

在光催化过程中,光催化剂被太阳能激发产生光生电子和空穴,来实现环境净化或能量转换,是应对全球变暖和能源短缺的有效途径之一.然而,光催化技术面临的主要瓶颈问题是光生载流子的低分离效率和高反应能垒.而催化剂本身的特性对这一点起到了决定性的作用.因此,催化剂的合理设计和改性是提高光催化效率的关键.金属有机框架(MOFs)是一...     

Solution for One-Dimensional Quantum Oscillator with Time-Dependent Frequency and Mass

Based on the generalized linear quantum transformation theory, we present a normal ordering evolution operator for onedimensional quant urn oscillator with time-dependent frequency and mass, then give the exact expression of the evolution matrix elements, wave function and expectation value of arbitrary observable.     

微扰QCD演化过程中存在遮蔽效应的一个证据

核子的纵向结构函数F_L以及虚光子吸收的纵向和横向散射截面的比值R_L在小X区域主要取决于胶子的分布函数.而胶子的初始分布函数的形式决定了在演化过程中是否要考虑遮蔽效应.利用新的动力学演化方程分析了F_L和R_L,发现在部分子演化过程中存在遮蔽现象.     

纤维/金属网增强层板低速冲击损伤机理和演化

本文首先通过落锤低速冲击实验测试了纯玻璃纤维增强环氧树脂复合材料和304不锈钢丝网(SSWM)/玻璃纤维混杂复合材料的力学性能,探究了SSWM嵌入数量对混杂复合材料抗冲击性能的影响．随后采用Abaqus有限元软件建立了混杂复合材料的低速冲击模型,分别采用三维Hashin失效准则和Jason-Cook破坏准则模拟了纤维/基体和SSWM的损伤;建立了基于表面接触的内聚力模型来模拟界面分层;编写了VUMAT用户子程序定义混杂复合材料层合板的渐进失效过程．结果表明：相较于纯玻璃纤维增强环氧树脂层合板,SSWM/玻璃纤维混杂增强环氧树脂层合板的抗冲击性能更优,其中铺层形式为铺层III的混杂复合材料抗冲击性能最佳．通过对比发现有限元仿真结果与实验结果吻合良好,表明建立的模型适用于SSWM/玻璃纤维混杂增强环氧树脂复合材料低速冲击损伤的评估．通过分析仿真结果发现混杂复合材料的低速冲击损伤主要是冲击区域的纤维断裂、基体破坏和层间分层;SSWM通过吸收和传递冲击能量从而提升了混杂复合材料的抗冲击性能．     

纳米水滴及真空中β-环糊精和对-甲基苯酚1:1包结物的约束动力学模拟研究

Two systems of 1: 1 inclusion of host β-cyclodextrin and guest p-cresol in nano-drip including 427 H2O molecules and in vacuum have been studied by the constrain molecular dynamics simulation technique with pcff force field and Rattle bond algorithm. The analysis on the dynamic structure of inclusion and radial distribution function of several kinds of oxygen atoms shows that the CD inclusion was stable during the simulation time period in two systems and none of water molecule was found to move into the CD cavity in the drip within 200 ps which conformed the hydrophobic property of CD cavity. In the drip,an obvious hydration caused by H-bonding existing in the CD hydrophilic outsides was observed,and it agreed well with the CD properties. The obvious H-bonding interactions existing between phenyl hydroxyl and water molecules in the drip and between phenyl hydroxyl and CD cavity in vacuum made the guest molecule insert into the CD cavity shallower in drip case than in vacuum case. It was concluded that the constrain molecular dynamics simulation technique can be used to investigate the dynamic behavior of CD aqueous solution.     

集中紧致原理在p-Laplacian发展方程中的应用

应用集中紧致原理研究了具有强非线性源的P-Laplacian发展方程的整体解的渐近性。     

MOF衍生的分层多孔三维N-CoPx/Ni2P大电流密度下加速析氢

氢气(H2)具有能量密度高、环境友好等优点,是一种很有前景的清洁能源载体.目前,电催化水裂解大规模制氢被认为是一种理想可行的方法.析氢反应(HER)涉及多个步骤,首先形成吸附的氢(Volmer步骤),然后是脱附步骤(Heyrovsky步骤)或两个相邻的吸附氢形成H2(Tafel步骤).与酸性介质相比,碱性介质中的HER...     

工程施工路径相关性的数值仿真

本文将损伤理论与时变力学耦联,形成用于模似施工的损伤时变力学方法,文中推导了基本方程和数值化算式。利用时变分析法对某地下煤层开采过程进行计算机仿真分析,给出了三种不同路径下开采引起地表沉陷的时空演化图,并进行对比分析。对体现出的位移、损伤与施工路径相关现象进行了探讨,并定量给出损伤时变分析下不同开采路径造成的最终力学状态的差别。本文中损伤时变力学方法为施工过程分析提供了一种新方法与手段。     

A Systematic Analysis of Human Activity on Landform Evolution of Loess Plateau——Taking loess plateau area in Gansu Province as an example

It is common knowledge that landform evolutionary process is controlled bytwo processes,endogenic forces processes,and exogenic forces process.Endogenicforces and exogenic forces processes history is as long as the earth's history.Comparing with landform evolutionary history,human history is a very shortinstance.But people have to undertake cultivation,animal husbandry and otherproductive activities for their living since they came to the world.This affectslandform evolutionary process.Especially,the effect of human activity on landformevolution of loess plateau is becoming more and more violent for several thou-sand years.Watersoil erosion is one of very important landform evolution pheno-menon of loess plateau.The authors have studied water-soil erosion of loess pla-teau area in Gansu province as example,analyzed the effect of human activity onwater-soil erosion.Thus the position and the effect of human activity on landformevolution of loess plateau have been shown from one point.     

Study on δ‐Form Complex in a Syndiotactic Polystyrene/Organic Molecules System, 1. Preferential Complexing Behavior of Xylene Isomers

To investigate the preferential complexing behavior of isomeric xylenes, syndiotactic polystyrene (sPS) membranes are prepared using varying compositions of m‐ and p‐xylene. Complex formation between sPS and the xylenes was studied by means of thermogravimetric and FT‐IR analyses to determine the exact amounts of solvent molecules present per styrene repeating unit. A preferential complexing ability of p‐xylene was revealed due to its favorable interaction with sPS.