A MICROSCOPIC MECHANISM OF LOW TEMPERATURE HELIUM RELEASE

⁴He ions of various energies and at various doses were implanted into three kinds of samples: TiH₂ films, high purity Ti pieces as-received and after hydrogenation. Thermal release of helium was monitored in situ by proton-enhanced backscattering. Low-temperature helium release was observed at T≤573K. Single jump model was used to calculate the active energies for the release. Based on the observations, a mechanism of helium cluster vacancy complex (He_mV_n-V_i) for low temperature helium release is proposed.     

Spin Switch and Qubit Register from a Spin Particle Controlled by a Time-Dependent Magnetic Field

A spin particle subjected to any time-dependent magnetic field is investigated in detail at different magnetic field configurations. Spin flip probability, spin alignment, cyclic and noncyclic nonadiabatic geometric phases are calculated exactly and their analytical expressions are presented. Our theoretical study shows that a spin particle controlled by a resonant time-dependent magnetic field can be used as efficient controllable devices of spin switch or qubit register.     

高频地波雷达LXI总线接口电路的设计

按照模块化和标准化的要求,设计了一种通用的LXI接口电路,它是以 ADSP-21062和DM9000A芯片为基础,利用大容量双口RAM作为LXI总线接口与功能电路之间高速数据传送的临时缓冲区,采取全双工的双向中断方式实现大数据包传送,满足基于LXI总线的高频地波雷达所有模件的接口要求.与其他传统总线相比,LXI总线充分利用了以太网的优势,实现远距离控制,同时可以减小系统尺寸,降低系统成本.测试结果表明,该接口电路工作正常可靠,传输速率达到12 Mb/s,满足高频地波雷达数据传输的要求.     

数学教育目的的深化和拓展:数学史的视角

我国古代数学教育的目的是培养具有一定数学知识(技艺)的官吏,到了近代,则在数学基础知识、基本技能、能力、思维、数学观、个性品质六方面提出了一定的目的要求.现代数学教育的目的可以概括为四个方面:使学生切实学好数学的基础知识;使学生形成基本的数学技能;发展学生的数学能力;培养学生良好的个性品质和学习习惯.     

具有AR(1)误差的非线性随机效应模型中自相关系数的扰动诊断

随机效应模型广泛应用于刻画重复测量数据的特征,Banerjee和Frees[1]用Cook距离,Lesaffre和Verbeke[2]用影响曲率分别对线性随机效应模型进行了分析.本文利用影响曲率对具有AR(1)误差的非线性随机效应模型中的自相关系数扰动进行了分析,得到了影响曲率的表达式,并且利用血浆药物渗透数据(Davidian和Gillinan[3])来说明分析方法的应用.     

空间低频光共焦扫描法透过散射介质成象

本文使用4-F光学系统实现低通空间频率滤波,采用空间低频光共焦扫描法透过散射介质成象,实验表明,光路中加入简单的空间滤波系统后,明显改善共焦扫描法的成象质量和分辨率。     

高效建立129S1/SvImJ 小鼠胚胎干细胞方法的探讨

选取超排后129S1/SvImJ品系小鼠的优质囊胚,使用辐照后冻存复苏的小鼠胚胎成纤维细胞作为饲养层,对比高浓度酶短时间消化法和低浓度酶长时间消化法,以0.25%胰酶-0.04%EDTA高浓度酶短时间消化法高效建立了4株小鼠胚胎干细胞系,建系率为36.31%.碱性磷酸酶,核型分析,体外分化和体内分化能力以及小鼠胚胎干细胞表面特异性分子标志0ct-4和Nanog的检测等表明,4个ES细胞系均为典型的小鼠胚胎干细胞系.所建立的ES细胞系为大规模培养ES细胞,进行后续的实验建立了理想的材料平台.     

D371树脂—火焰原子吸收光谱测定湿法冶金工艺的金

离子交换富集分离金，具有较好的动力学性能和较高的吸附容量。使金的吸附与离子交换过程在金的湿法冶金中日趋重要？本文研究用新型D371树脂在静态动态条件下吸附和解吸金的性能，拟定了一个离子交换树指分离富集火焰原子吸收光谱测定湿法冶金工艺中微量金的方法。     

Helium-hydrogen synergistic effects on swelling in in-situ multiple-ion beams irradiated steels

The development of reliable fusion energy is one of the most important challenges in this century. The accelerated degradation of structural materials in fusion reactors caused by neutron irradiation would cause severe problems. Due to the lack of suitable fusion neutron testing facilities, we have to rely on ion irradiation experiments to test candidate materials in fusion reactors. Moreover, fusion neutron irradiation effects are accompanied by the simultaneous transmutation production of helium and hydrogen. One important method to study the He-H synergistic effects in materials is multiple simultaneous ion beams (MSIB) irradiation that has been studied for decades. To date, there is no convincing conclusion on these He-H synergistic effects among these experiments. Recently, a multiple ion beam in-situ transmission electron microscopy (TEM) analysis facility was developed in Xiamen University (XIAMEN facility), which is the first triple beam system and the only in-running in-situ irradiation facility with TEM in China. In this work, we conducted the first high-temperature triple simultaneous ion beams irradiation experiment with TEM observation using the XIAMEN facility. The responses to in-situ triple-ion beams irradiation in austenitic steel 304L SS and ferritic/martensitic steel CLF-1 were studied and compared with the results in dual- and single-ion beam(s) irradiated steels. Synergistic effects were observed in MSIB irradiated steels. Helium was found to be critical for cavity formation, while hydrogen has strong synergistic effect on increasing swelling.     

基于麦克斯韦方程的交变电流长螺线管磁场

为了分析方波驱动长螺线管内磁场畸变机理,利用麦克斯韦方程研究了螺线管内外的磁场分布情况。首先,利用麦克斯韦方程,分别建立了正弦波驱动螺线管内外电场、磁场模型,并结合安培环路定律和电磁感应定律选取了合适的边界条件,得到了正弦波驱动长螺线管的磁场分布;其次,通过傅里叶变换将方波信号变换为多个正弦信号叠加的形式,从而得到了方波驱动长螺线管磁场分布;最后,通过仿真试验重点分析了方波驱动信号频率对磁场的影响,并得出结论:方波驱动长螺线管磁场波形会失真、畸变,驱动信号频率较低、距离螺线管轴线距离较近处,磁场的方波特性较好。