利率具有二阶自回归相依结构情形下的破产概率

在利率具有二阶自回归相依结构的假设下,研究了一类破产概率上界的估计问题.通过积分方程导出了破产概率的上界,所得结果部分地推广了古典风险模型及现有的部分结果.国家自然科学基金青年基金(10201010);数学天元青年基金(10126014)资助项

A Water-saving Device for Solar-powered Water Heater

介绍一种用于热水器的节水装置的工作原理,该装置由温度检测系统、PlC控制系统及执行机构(电磁阀)等三部分组成。其节水的功能在于,当用户需要使用热水时,启动节水装置开关,系统自动检测并将原本储存在热水器与水龙头之间的冷水泵回主水管道,直至热水到达出水口时恢复普通使用状态,从而避免将大量冷水放流而造成的水资源浪费。The principle of work of a water-saving device for the solar-powered water heater is presented.The device is made up of three parts: the temperature examination module,the PLC control module and the executive module(two solenoid valves).The saving water process of this device is as follows: when the user needs to use the hot water,open the switch of the device,then the device will make the cold water which between the hot water tank and the tap back to the main pipeline until the hot water gets to the tap.Then the user can use the hot water normally.In this way,lots of water waste can be avoided

DSMC碰撞模型参数对高超声速化学反应流的影响

直接模拟蒙特卡罗(DSMC)方法是一种高效、精确的气体流动模拟方法。DSMC方法高效计算的关键在于它处理分子水平上的输运,内能松弛和化学反应过程使用的唯像模型。例如,Bird的变径硬球(VHS)模型是DSMC中处理弹性碰撞最成功的模型,该模型试图只再现气体粘度对温度的指数依赖关系,而不是对粒子之间的相互作用进行详细的建模。唯象模型参数的准确性对DSMC仿真的准确性至关重要。在早期的发展过程中,这些唯象碰撞模型参数通常是根据实验测得的有限温度范围输运系数数据进行校准的。人们已经认识到这些参数在高温范围内可能是不准确的,例如,在再入飞行中遇到的温度大于10000K的情况。因此,最近新的高温空气参数被推荐,通过对广泛使用的碰撞模型,如VHS和可变软球(VSS)模型,基于从头计算的碰撞积分数据进行参数标定。这些基于从头计算的碰撞参数的准确性已经被证明了。本文针对DSMC模拟最常用的唯象碰撞模型,通过拟合基于从头计算的碰撞积分数据对DSMC模型参数进行重新标定。在本文中,我们将通过使用一个最新开发的采用特定碰撞配对策略的DSMC程序研究碰撞参数对高超声速化学反应流动模拟流场特性的影响。圆柱体的高超声速反应流的初步结果表明,不同的DSMC碰撞模型参数,激波位置、表面热流率等流场特性有显著变化。本文将进行分析以确定模型参数影响流动特性的通道(例如扩散或反应过程)

稀土化合物RE(HCO_2)_3(HNO_2)的合成与表征

合成了系列新化合物rE（HCO2）3（HnO2）（H2CO2）（rE＝y，Tb，dy，HO，Er，yb，TM），用X射线方法表征了其结构。单晶结构分析表明此新类型的结构为正交晶系且具有非中心对称空间群（20）C2221，晶体结构为三维网络结构，结构的..

金属性Zintl相化合物RE_3Cu_3Sb_4(RE=Nd,Sm,Tb,Dy,Ho)的合成、结构及成键特性

用电弧熔炼方法合成了化合物rE3Cu3Sb4（rE＝ nd，SM ，Tb，dy，HO）， 采用粉末X射线衍射方法测定了其晶体结构。化合物属立方晶系，y3Au3Sb4 类型， 空间群I43d（nO.220），皮尔森玛CI40。晶胞参数：nd3Cu3Sb4 ：A＝0.96749（1） nM， V＝0.90561（3） nM3；SM3Cu3Sb4：A＝ -0.96145（1） nM ，V＝0.88875（3） nM3 ；Tb3Cu3Sb4： A＝0.95362（1） nM ， V＝ 0.86721（3）nM3；dy3Cu3Sb4： A＝0.95088（1） nM ， V＝0.85975（3） nM3；HO3Cu3Sb4 ： A＝0.9488（2） nM ， V＝0.8541（5） nM3。每个单胞中包含4 个化合式量。此结构中，Cu 原子均处于Sb 原子所形成的配位四面体中心， 这些共价结合的配位四面体通过共顶最终联接形成三维CuSb 网络，稀土原子则散布在网络之间的空隙中。化合物电荷平衡结构式可表示为rE3＋3 Cu1＋3 Sb3-4 ， 化合物具有导电性， 为金属性zInTl 相。原子成键具有典型过渡性。原子的“配位数”遵从配位环境规律。化合物

Program Package for Three Dimensional Crystal Structure Animation

将计算机三维动画技术引入晶体结构研究 ,用C语言设计制作出用于绘制动态三维真彩色晶体结构图的大型计算机绘图软件包———晶体结构三维实体造型系统软件包 3DSPLOTS ,利用晶格常数、空间群、原子坐标和原子半径等参数在计算机模拟的三维空间内制作出晶体结构的动画影像 ,引入三维晶体结构动画概念 ,使晶体结构的绘图技术从静态图向动态图发展。The computer technique of three dimensional animation was first introducedinto graphics of crystal structures. A program package 3DSPLOTS has been designed for buildingthree dimensional model of crystal structures. It generates ball and stick or polyhedral diagrams,and can plot atoms as spheres in true color. Polyhedra can be of any complexity besides triangle,tetrahedra and octahedra. The files exported by 3DSPLOTS can be imported to 3D Studio ofAutodesk. Fifty animations of crystal structures such as Diamond, Graphite, Fluorite, Sphalerite,Niccolite, Chalcopyrite, Rutile, Spinel, Corundum, Albite etc, have been plotted and publishedin disk of CD R.山东大学晶体材料国家重点实验室开放基金;; 国氏博士后基

Probing nanoscale spatial distribution of plasmonically excited hot carriers

表面等离激元（SP）效应可产生远高于热平衡下费米能级能量的热电子-空穴对（热载流子），从而能够引发和促进相关的光电或者化学过程，为在纳米尺度上高效利用光能实现物质和能量转化提供了极为有效的手段，化学化工学院任斌教授课题组利用前期自主发展的电化学针尖增强拉曼光谱技术，通过调控电位开关SP热载流子催化的反应，实现了有效热载流子催化反应区域的纳米分辨成像，使反应区域在实空间的分布可视化。实验上获得了有效热载流子的输运距离，从而证明了能量越高的热载流子越需要在更短的输运距离范围内收集捕获。 该工作在任斌教授和王翔副教授的共同指导下完成。实验主要由化学化工学院已毕业博士生黄声超完成。理论计算主要由电子科学与技术学院的朱锦峰副教授和已毕业硕士生李察微完成。此外，化学化工学院已毕业硕士生赵庆庆、博后何玉韩和胡树等人也参与了部分研究与课题讨论。【Abstract】Surface plasmons (SPs) of metals enable the tight focusing and strong absorption of light to realize an efficient utilization of photons at nanoscale. In particular, the SP-generated hot carriers have emerged as a promising way to efficiently drive photochemical and photoelectric processes under moderate conditions. In situ measuring of the transport process and spatial distribution of hot carriers in real space is crucial to efficiently capture the hot carriers.Here, we use electrochemical tip-enhanced Raman spectroscopy (EC-TERS) to in situmonitor an SP-driven decarboxylation and resolve the spatial distribution of hot carriers with a nanometer spatial resolution. The transport distance of about 20 nm for the reactive hot carriers is obtained from the TERS imaging result. The hot carriers with a higher energy have a shorter transport distance. These conclusions can be guides for the design and arrangement of reactants and devices to efficiently make use of plasmonic hot carriers.The authors acknowledge the financial supports from MOST of China (2016YFA0200601), NSFC (21633005, 21790354, 21503181, 21711530704, U1830116), Natural Science Foundation of Fujian Province (2016J05046), China Postdoctoral Science Foundation (2017M622062) and the Fundamental Research Funds for the Central Universities (20720190010).本研究工作得到了国家自然科学基金委和科技部等的资助和支持

Syntheses and characterizations of rare earth compounds RE(HCO2)(3)(HNO2) (H2CO2) (RE = Y, Tb, Dy, Ho, Er, Yb, Tm)

A series of novel inclusion compounds with compositions of RE(HCO2)(3)(HNO2)( H2CO2) (RE = Y, Tb, Dy, Ho, Er, Yb, Tm) were synthesized and structures were characterized by X-ray methods. The orthorhombic structure was shown to be a new type with a non-centrosymmetric space group (20) C222(1) by single crystal structure determinations. It is characterized by networks of rare earth centered square anti-prisms formed by eight oxygen atoms through bridging carbon and nitrogen atoms. The guest formic acid molecules H2CO2 are distributed inside the open tunnels along the crystallographic a axis. The magnetic susceptibility measurements show the heavy rare earth compounds follow the Curie-Weiss law and the calculated numbers of Bohr magnetons are consistent with the RE3+ ions. The yttrium compound shows very weak temperature independent paramagnetism

铟硼磷酸盐结构中的交叠生长规律研究

Several indium borophosphates have been reported recently, including KIn[BP2O8(OH)](I) and NaIn[BP2O8(OH)](H). The latter two compounds were synthesized under mild hydrothermal conditions, and have the same molar ratio (M-I:In:B:P:O:H) in molecular formula but with different structure types. Compound I crystallizes in the triclinic system with space group P (1) over bar (No.2), a=0.52638(4) nm, b=0.84791(5) nm, c=0.81469(9) nm, alpha=91.1741(7)degrees, beta=93.061(7)degrees, gamma=79.823(5)degrees, V=0.3573 nm(3), Z=2; while compound II possesses a monoclinic structure with space group P2(1)/n (No.14) with a=0.5177(1) nm, b=1.6815(3) nm, c=0.7684(2) nm, beta=94.10(3)degrees, V=0.6672(2) nm(3), Z=4. Eight- membered-ring and six-membered-ring are formed by alternating borate, phosphate tetrahedra and In-coordination octahedron sharing corners via common oxygen atoms in compound I and H respectively. The polyhedra in the structure are oriented along certain direction to form alternating layered fragments. These two structure types can be considered as intergrowth structures, which consist of the same layered fragments growing in different orientations. Other structure intergrowth possibilities are also expected in similar systems

改良分子信标-双重实时荧光PCR快速检测SARS病毒

目的建立改良分子信标-双重实时荧光PCR检测SARS病毒的方法,用于SARS的早期诊断和动物溯源。方法利用改良分子信标技术、装甲RNA和双片段双色荧光技术,根据GenBank公布的SARS病毒聚合酶基因1b的阅读开放框架结构的保守序列,自行设计一对引物和探针,以部分临床标本的酶联吸附实验结果和传统细胞培养方法作为对照,建立分子信标检测SARS病毒的方法。对368份临床标本(咽漱液、血液、粪便、尿液)、52份细胞培养液和50份动物标本进行荧光PCR扩增。结果分子信标检测SARS病毒的方法灵敏度为10～100个拷贝ml,与流感病毒等呼吸道病毒无交叉反应。分子信标检测368份临床标本,20份阳性。其中确诊病例阳性率为21.27%(1047),确诊病例的咽漱液阳性率为43.48%,还分别从粪便和血清中检测到SARS病毒。52份细胞培养液,29份阳性,阳性率为55.77%。50份动物标本,23份阳性,阳性率为46%。结论改良分子信标-双重实时荧光PCR检测SARS病毒方法灵敏度高、特异性强,可用于SARS的临床早期诊断和动物溯源