断裂物理参量——解理断裂应力σ_f~*的研究

1.研究断裂物理的必要性断裂力学在工程界受到广泛的重视并取得了可喜的成果。在运用之余,人们常常会问:断裂力学中所采用的K_(Ic),J_(Ic),COD这些新的应用力学参量与材料的微观结构(组织、位错、夹杂形态)有什么内在的联系?怎样从材料的组织特征来计算它的强度和韧性,并以此来指导材料的成分配比和生产工艺使它的性能有     

气相色谱-串联质谱法测定螺旋霉素中的N-亚硝基二甲胺

采用气相色谱-串联质谱法(GC-MS/MS),建立了螺旋霉素原料药中N-亚硝基二甲胺(NDMA)含量的检测方法.样品的制备使用液液萃取法,先将螺旋霉素溶于硫酸溶液,再用二氯甲烷萃取得到待测液.质谱检测使用多反应扫描模式,定量离子对为74.0→4.0,定性离子对为74.0→42.0.在0.25～50 μg/L范围内的ND...     

Orlicz-Bochner序列空间中的非l_n~((1))点与一致非l_n~((1))点（英文）

本文给出Banach空间中非l_n~((1))点和一致非l_n~((1))点的部分特征,在此基础上得到了Orlicz-Bochner序列空间中非l_n~((1))点和一致非l_n~((1))点的判据.     

Preparation and characterization of thick cubic boron nitride films

Cubic boron nitride （c-BN） films are prepared by the radio frequency magnetron sputtering technique. The stresses and crystallinities of the films are estimated by the Fourier transform infrared spectroscopy of c-BN samples, including the peak shifts and varieties of full widths at half maximum. The effects of the B-C-N interlayer and the two-stage deposition method on the c-BN films are investigated. Then the thick and stable c-BN films are prepared by a combination of the two methods. The properties of the interlayer and film are also characterized.     

马氏体时效钢的时效结构

本文利用透射电子显微相和电子衍射相对18Ni马氏体时效钢中沉淀强化相和时效结构的结晶学性质进行了研究。利用数个不同晶带的衍射相,一致地鉴别出同时存在Ni₃Mo,Ni₃Ti沉淀相和弥散的逆转变奥氏体,并且确定了它们相对马氏体基体的取向关系。证明了沉淀相、逆转变奥氏体与基体之间,密排面和密排方向都相互平行。指出在透射电子显微相中看到的魏氏型沉淀结构,实际上是由棒状沉淀相构成的三维空间格条结构,其中棒状沉淀相的长度方向平行于基体的四个〈111〉型方向。所观察到的扩张位错和位错塞积的真实性需要更多的实验证实。从结构观点,讨论了沿位错线的沉淀过程,并提出了钴钼交互作用的可能机制。     

考虑退货情形下的闭环供应链双源库存控制策略

假设再制造闭环供应链由单个制造商和单个零售商组成,考虑制造商产品回收率、退货率和废旧产品再制造率的不确定性,建立再制造环节废旧产品的最优检测时间、购买时间和闭环供应链最低成本的数学模型.利用回收率、退货率和再制造率计算废旧产品的最优检测和购买的时间间隔,分析再制造环节中双源库存的成本最小化问题.研究表明:再制造环节可降低闭环供应链的双源库存成本,但随着回收率的增加,总成本先下降后增加;在回收率、退货率和再制造率三者共同作用下,最优检测和购买时间间隔的设置可降低双源库存成本,优化资源配置.     

Field Emission Enhancement of Carbon Nanotubes by Surface Modification

By employing a multi-walled carbon nanotube （MWCNT） film as the substrate, we obtain Fe tipped carbon nanorods or carbon nanoparticles grown on the outer walls of MWCNTs by combining sputtering deposition of Fe films and rf plasma enhanced chemical vapour deposition at high temperature. Scanning electron microscopy and high-resolution transmission electron microscopy are used to examine the structure of carbon nanorods and carbon nanoparticles. In addition, the formation mechanism is discussed briefly. The electron field emission tests indicate that the turn-on field （at 10μA/cm^2） of the treated MWCNT films decreases from 2.4 V/μm to O. 79 V/μm and the field emission current is relatively stable. The enhanced field enhancement factor, increasing emission densities coming from the grown nanorods and nanoparticles, and H terminated by H plasma a11 are responsible for the enhancement of the field enhancement factor.     

Study on the dose rate upset effect of partially depleted silicon-on-insulator static random access memory

This paper implements the study on the Dose Rate Upset effect of PDSOI SRAM (Partially Depleted Silicon-On-Insulator Static Random Access Memory) with the Qiangguang-I accelerator in Northwest Institute of Nuclear Technology. The SRAM (Static Random Access Memory) chips are developed by the Institute of Microelectronics of Chinese Academy of Sciences. It uses the full address test mode to determine the upset mechanisms. Specified address test is taken in the same time. The test results indicate that the upset threshold of the PDSOI SRAM is about 1x10⁸Gy(Si)/s. However, there are few bits upset when the dose rate reaches up to 1.58x10⁹Gy(Si)/s. The SRAM circuit can still work after the high level γ ray pulse. Finally, the upset mechanism is determined to be the rail span collapse by comparing the critical charge with the collected charge after γ ray pulse. The physical locations of upset cells are plotted in the layout of the SRAM to investigate the layout defect. Then, some layout optimizations have been taken to improve the dose rate hardened performance of the PDSOI SRAM.     

一种简单的判断方法

在混联电路中,当部分电路的电阻发生变化时,就会引起整个电路中各用电器两端的电压及流过它们的电流发生变化.要判断它们的变化情况,常用方法是整体分析和局部分析相结合,分析电压和分析电流相结合.分析过程比较繁琐,容易出错,大部分学生感到较难掌握.现通过两个例子总结出一个快速准确的方法.