一类非线性双曲—抛物耦合方程组的周期边值问题

§1 引言在循环燃料反应堆中,其中心密度u及温度v满足下列方程组:     

概率论在就业决策中的一个应用

随着科学技术的飞速发展，生产力水平正在不断提高，各行各业的就业岗位已经远远不能满足即将从业者的需求，就业“供”与“需”之间的予盾越来越突出．对于一名即将从业的人（尤其是即将毕业的大学生）来说，面对强手如林的竞争局面，除了刻苦学习必备的基础知识，努力训练从业的基本技能以外，在竞争工作岗位时，如何进行就业的决策，也是一个不容忽视的问题．本文通过几种具体情况，对这个问题进行一点探讨．     

Effects of Substrate Temperature on Helium Content and Microstructure of Nanocrystalline Titanium Films

Helium-charged nanocrystalline titanium films have been deposited by HeAr magnetron co-sputtering. The effects of substrate temperature on the helium content and microstructure of the nanocrystalline titanium films have been studied. The results indicate that helium atoms with a high concentration are evenly incorporated in the deposited titanium films. When the substrate temperature increases from 60℃ to 350℃ while the other deposition＇parameters are fixed, the helium content decreases gradually from 38.6 at.% to 9.2at.%, which proves that nanocrystalline Ti films have a great helium storage capacity. The 20 angle of the Bragg peak of （002） crystal planes of the He-charged Ti film shifts to a lower angle and that of （100） crystal plane is unchanged as compared with that of the pure Ti film, which indicates that the lattice parameter c increases and a keeps at the primitive value. The grain refining and helium damage result in the diffraction peak broadening.     

Total Dose Radiation Tolerance of Phase Change Memory Cell with GeSbTe Alloy

Phase change memory （PCM） cell array is fabricated by a standard complementary metal-oxide-semiconductor process and the subsequent special fabrication technique. A chalcogenide Ge2Sb2Te5 film in thickness 50hm deposited by rf magnetron sputtering is used as storage medium for the PCM cell. Large snap-back effect is observed in current-voltage characteristics, indicating the phase transition from an amorphous state （higher resistance state） to the crystalline state （lower resistance state）. The resistance of amorphous state is two orders of magnitude larger than that of the crystalline state from the resistance measurement, and the threshold current needed for phase transition of our fabricated PCM cell array is very low （only several μA）. An x-ray total dose radiation test is carried out on the PCM cell array and the results show that this kind of PCM cell has excellent total dose radiation tolerance with total dose up to 2 ×10^6 rad（Si）, which makes it attractive for space-based applications.     

多发弹丸发射系统阀门电源及可编程发射控制器的研制

多发弹丸发射系统是我院20世纪90年代从俄罗斯引进的设备，用于发射弹丸的快阀门电源属于非标产品，其备件缺乏，维修困难。为保证HL-2A装置弹丸注入实验顺利进行，根据设计要求，研制了这套弹丸快阀电源和可编程发射控制器。它们之间的连接如图1所示。     

激光推进的基本原理和实验进展综述

激光推进是一种新型的推进模式,按作用机理可分为大气模式激光推进和火箭烧蚀模式激光推进两种。分析了两种推进模式的作用原理,论述了激光推进的最新研究进展。     

画幅不稳定性的测定

补偿式高速摄影机拍摄频率高、画幅数量大,如采用单次曝光法测量画幅不稳定性,虽可直接求得画幅不稳定性的数值,但判读量大。利用游标原理的两次曝光法可以迅速对底片做出判读。