几何Lévy模型中鞅测度的均值修正法及应用

在几何Levy过程模型中,利用均值修正方法构造了一个鞅测度Q~(m_0).证明了Q~(m_0)为等价鞅测度的充要条件是Levy过程具有Brownian运动部分.对于纯跳过程,证明了欧式看涨期权在Q~(m_0)下的价格仍然无套利.     

Carbide Identification in Different Regions of a Thin Metal Film Covering on an HPHT As-Grown Diamond Single Crystal from Ni-Mn-C System

Diamond single crystals were synthesized in the presence of NI-Mn catalyst under high temperature and high pressure(HPHT).A thin metal film covering on as-grown diamond formed during diamond growth was examined using transmission electron microscopy.It was shown that phase compositions of the region near the as-grown diamond are different form those of other regions in the film.     

逆热传导方程的一个正则化方法

考虑了标准的一维逆热传导方程.问题是不适定的,即解不连续地依赖于数据.通过Fourier逼近的方法进行正则化处理,提出了一个新的算法,理论分析和数值实验均表明该算法是稳定的;该算法不仅保留了测量数据的部分高频成份,同时还具有相同的精度和计算复杂性.     

游泳池采用硅藻土过滤循环水系统的设计及运行

简要介绍我国研究开发的硅藻土过滤技术应用于游泳池循环水处理的设计及运行方法，并结合实际工程一年多的运行实践，提出了运用这些方法处理实际问题所采用的技术措施。     

直角三角形的“半”缘

直角三角形是我们常见的图形,它的一些特性与"半"很有缘,理解并掌握好直角三角形的这些特性,可以很好地帮助我们进行解题.1.直角三角形中,30°角所对的边等于斜边的一半.     

Current Induced Non-Volatile Resistive Switching Effect in Silicon Devices with Large Magnetoresistance

We develop a non-volatile resistive switching device in a Si-SiO2-Mg structure with an on/off ratio of about 4.5 at a certain transition voltage after being stimulated by a large current. It is observed that the resistance transition voltage Vt shifts reproducibly under a reversed large current. By applying a reading voltage in the range of Vt, non-volatile resistive switching phenomena with an endurance of more than 80 cycles are observed. Moreover, it is also found that the magnetic field could shift Vt to higher values, yielding a voltage dependent room-temperature magnetoresistance in the range of 10^3 % at 1 T. The multifunctional properties of the silicon device suggested by this work may be beneficial to the silicon based industry.     

滑轨导向式静/动态双轴拉伸实验技术

基于液压伺服高速加载系统,发展了一种材料双轴拉伸力学性能测试技术。利用锥面接触导向驱动方法,把加载锤竖直方向的驱动力转化为水平方向的双轴驱动力,从而实现对十字形试样平面双轴加载。借助有限元数值模拟手段优化了锥面接触角和十字形试样尺寸。当接触锥角为45°时,既有较好的水平驱动转化效率,同时又保持较小的接触力,确保水平驱动加载各组件在弹性变形范围内,可多次重复使用。确定了加载臂狭缝个数、狭缝与减薄区边缘长度和标距段厚度等试样设计关键参数,在十字形试样测试标距段内实现了均匀变形。设计了测力夹持一体化导杆和非接触光学全场应变测试系统,准确获得了试样的应力和应变。利用此平面双轴拉伸加载装置,开展2024-T351铝合金板单轴拉伸实验和激光探测同步性验证实验,验证装置设计的可行性;开展铝合金板材在不同加载速率下的双轴拉伸实验,得到在双轴加载下铝合金板材应力应变曲线,并与单轴加载下实验结果进行了对比分析。