Behaviour of helium after implantation in molybdenum

This study deals with the behaviour of helium in a molybdenum liner dedicated to the retention of fission products. More precisely this work contributes to evaluate the release of implanted helium when the gas has precipitated into nanometric bubbles close to the free surface. A simple model dedicated to calculate the helium release in such a condition is presented. The specificity of this model lays on the assumption that the gas is in equilibrium with a simple distribution of growing bubbles. This effort is encouraging since the calculated helium release fits an experimental dataset with a set of parameters in good agreement with the literature.     

The adsorption of Ni on the Mo(111) crystal face

STM, LEED, AES, TDS and Δ? measurements were performed to investigate the adsorption of Ni on the molybdenum (111) surface. The adsorption energy of Ni atoms on the Mo(111) surface was determined. At 300 K the layer-by-layer growth mechanism was observed. No faceting of the Mo(111) surface was observed after the annealing. Annealing leads to the adsorbate agglomeration and formation of Ni islands in the shape of pyramids.     

基于VxWorks操作系统的USB 2.0驱动分析

现代智能仪器中已经开始使用USB接口作为标准输入输出接口;智能仪器对实时性要求的提高,使得VxWorks操作系统在其中得到了广泛应用。本文分析了VxWorks操作系统下USB2．0驱动程序模型结构与功能,详细地说明了USB2．0主机协议栈。在此基础上,给出了智能仪器中使用USB2．0主机栈来完成USB主机功能的方法和注意事项。     

基于组合导航系统的嵌入式实时数据库研究

文中分析了VxWorks嵌入式操作系统中的实时数据库组成，构建了嵌入式实时数据库模型，对嵌入式数据结构、内存数据库和历史数据库进行软件设计，实现了嵌入式数据库在组合导航系统软件中的应用。     

Helium solubility and behaviour in uranium dioxide

A set of devices was developed in order to infuse UO₂ disks with helium, at high temperature and pressure, to measure the helium infused quantity and from these data to calculate the helium solubility in the UO₂ matrix. Samples of UO₂ single crystal and UO₂ polycrystal were infused at a temperature of 1473 and 1743 K in a helium atmosphere ranging between 50 and 100 MPa. These samples were then annealed and the helium released was measured with a mass spectrometer. From the obtained spectra it was possible to give an interpretation of the helium release mechanism and to calculate its solubility in the UO₂ lattice in these specific thermodynamic conditions. Additionally to the helium solubility measurement from infused samples, a 37 years old sample of ²³⁸PuO₂, retrieved from an old ²⁴²Cm radioisotope thermoelectric generator (RTG), containing radiogenic helium, was also measured to widen perspectives of this kind of measurements to damaged sample more representative of spent fuel.     

An inelastic thermal spike model to calculate ion induced desorption yields

Ion induced desorption is a severe luminosity limitation for low charge state heavy ion accelerators. Therefore, it was intensively investigated in dedicated experiments during recent years. Several experimental results were obtained providing numerous desorption yields for different ion beam parameters and different materials as well as surface treatments. The heavy ion induced desorption was identified as a pure surface cleaning effect. Nevertheless it was shown that the yields have a strong link to the irradiated material. The initial desorption yield decreases during the irradiation reaching a dynamic equilibrium. Desorption yields of several hundred molecules per incident ion from one monolayer adsorbed gas can not be explained with the geometrical cross section of the projectile. Therefore we have expanded the inelastic thermal spike model to describe the process as thermal desorption from a microscopic heated region. The obtained results of this extended model represent very well the numbers from many experimental studies.     

VxWorks操作系统中SCTP协议栈的研究与实现

随着IP网向多业务网的发展,尤其是近年来VoIP技术的发展,需要在IP网络上传输有严格时间要求的信令。IETF的信令传输工作组(SIGTRAN)定义了一种新的传输层协议：SCTP(流控制传输协议),用于在IP网上提供可靠的报文传输。本文实现了BSD的SCTP协议栈源代码到VxWorks上的移植。同时分析了VxWorks中SCTP协议栈的实际运行性能。     

Fusion-Fission Transmutation Scheme—Efficient destruction of nuclear waste

A fusion-assisted transmutation system for the destruction of transuranic nuclear waste is developed by combining a subcritical fusion-fission hybrid assembly uniquely equipped to burn the worst thermal nonfissile transuranic isotopes with a new fuel cycle that uses cheaper light water reactors for most of the transmutation. The center piece of this fuel cycle, the high power density compact fusion neutron source (100 MW, outer radius <3 m), is made possible by a new divertor with a heat-handling capacity five times that of the standard alternative. The number of hybrids needed to destroy a given amount of waste is an order of magnitude below the corresponding number of critical fast-spectrum reactors (FRs) as the latter cannot fully exploit the new fuel cycle. Also, the time needed for 99% transuranic waste destruction reduces from centuries (with FR) to decades.     

嵌入式操作系统VxWorks下CPCI设备驱动程序开发

VxWorks是WindRiver公司开发的嵌入式实时操作系统,广泛地应用于航空航天、工业控制、通信等领域;在简单地介绍了VxWorks操作系统之后,分析了VxWorks下CPCI设备驱动程序的实现方法;以CPCI9112数据采集卡的驱动程序开发为例,介绍了CompactPCI总线以及PCI接口芯片S5935,重点说明了在VxWorks下以定时器和中断方式实现模数转换驱动程序的方法和编程要点,并给出了部分关键代码;在飞行控制半实物仿真系统中的运行结果表明驱动程序运行稳定、可靠.     

基于工控机的微机保护智能同步数据采集卡

工控机式保护与综合自动化有很多优越性和广阔的发展前景，微机保护智能同步数据采集卡是作者研究的基于PC工控机的集中式微机保护与综合自动化系统的核心。文中着重介绍其功能、硬件组成、核心器件CPLD的逻辑功能、与PC机的数据传输机制，以及此采集卡的Windows虚拟驱动程序(VxD)的编写方法。