Roles of minor additions in formation and properties of bulk metallic glasses

Bulk metallic glasses (BMGs) are of current interest worldwide in materials science and engineering because of their unique properties. Exploring BMGs materials becomes one of the hottest topics in the materials science field. To date, there is very active worldwide development of new BMGs, and extensive efforts have been carried out to understand and improve the glass-forming ability of metallic materials supported by large government and industry programs in North America, Asia, and Europe. Minor addition or microalloying technique, which has been widely used in other metallurgical fields, plays effective and important roles in formation, crystallization, thermal stability and property improvement of BMGs. This simple approach provides a powerful tool for the BMG-forming alloys development and design. In this paper, we present a comprehensive review of the history and the recent developments of this technique in the field of BMGs. The roles of the minor addition in the formation and the properties of the BMGs and the BMG-based composites will be discussed and summarized within the framework of thermodynamics, kinetics and microstructure. The empirical criteria, or the principles and guidelines for the applications of the technique in BMG field are outlined.     

TiSiW12O40/TiO2催化合成丙酸正丙酯

研究了固载杂多酸盐TiSiW12O40/TiO2催化丙酸与正丙醇的酯化反应，探讨了催化剂用量，反应时间及醇酸摩尔比对酯收率的影响。当醇酸摩尔比为1.3:1，催化剂的量为醇酸总质量的1.5%。反应时间为1.0h，酯产率可达71.4%以上，采用该催化剂合成丙酸正丙酯不仅酯化反应温度低，反应时间较短，催化剂用量少，而且可较好地回收利用，可降低成本；因此，TiSiW12O40/TiO2是合成丙酸正丙酯的优良催化剂，具有良好的应用前景。     

聚氨酯/聚(甲基丙烯酸甲酯-甲基丙烯酸丁酯)互穿聚合物网络聚合物的阻尼性能

采用本体聚合法合成出一系列阻尼性能良好的聚氨酯/聚(甲基丙烯酸甲酯-甲基丙烯酸丁酯)(PU/P(MMA-BMA))互穿聚合物网络(IPN)聚合物,通过动态力学分析方法表征了PU/P(MMA-BMA)IPN聚合物的阻尼性能。探讨了加入催化剂、高温后处理、交联剂用量及PU与P(MMA-BMA)的质量比对PU/P(MMA-BMA)IPN聚合物阻尼性能的影响。实验结果表明,经高温后处理后,以二月桂酸二丁基锡为催化剂、交联剂二乙烯基苯用量(占MMA和BMA的摩尔分数)为1.5%、PU与P(MMA-BMA)的质量比接近1或小于1时,PU/P(MMA-BMA)IPN聚合物具有良好的阻尼性能。     

浮栅技术及其应用

介绍了浮栅技术的基本原理及应用情况。井对2种应用了浮栅技术的典型器件-浮栅MOS晶体管和神MOS晶体管做了详细介绍，分析了他们的基本结构和工作原理，以及建立浮栅MOS晶体管的等效模型，并说明了他们的应用情况及存在的不足。     

主动约束层阻尼板结构动力学建模研究

将有限元法和GHM法相结合，给出了建立主动约束层阻尼（ACLD）板结构动力学模型的新方法。建模时，考虑到粘弹材料（VEM）的纵向位移影响，采用GHM方法描述VEM的本构关系，解决了VEM的力学特性随温度和频率变化的难点，避免因VEM的复杂本构关系而产生的微分积分方程。算例表明本文给出的建模方法是准确的，ACLD结构能够有效控制结构振动。     

P／MCs新型复合材料制备、结构及阻尼性能

采用特殊的渗流法所制备的新型Ｐ／ＭＣｓ复合材料，由高分子聚合物与蜂窝状铝架组成，它具有优异的阻尼性能，并简述了结构对阻尼的影响     

^17O系统的R矩阵分析

采用多道多能级R矩阵理论,全面系统地分析~(17)O系统中10.5 MeV激发能以下有关~(16)O(n,n)~(16)O·~(16)O(n,a)~(13)C和~(13)C(a,a)~(13)C的全部实验数据。有关~(16)O的中子反应截面计算值被收入中国评价数据库CENDL-2和美国的评价数据库ENDF/B-6。对在R矩阵分析中如何确定本底、道半径和边界条件等问题予以讨论。     

Importance of the choice of the profile model for ap-n junction in the location of deep levels

The energy levels introduced by Pt in silicon have been measured in a non-abruptp ⁺-n junction using constant-capacitance thermal-emission rate measurements and a numerical simulation of high frequency-capacitance. Two levels have been detected with activation energies of:E _c -E _T = 0.22 eV with acceptor character andE _T -E _v = 0.34 eV with donor character. The sample preparation and diffusion of Pt is similar to previous works in which an acceptor levelE _c -E _T = 0.34 eV was found instead of or besides a donorlike levelE _T -E _v = 0.34 eV. Our numerical calculation of the shallow-impurity profile points to the existence of a gradual transition near the metallurgical junction for these samples. We have demonstrated that the well-known model of an abrupt junction is not appropriate for these types of junctions, and could lead to errors in the location attributed to the detected levels. Simulation of the electrical behavior leads to the non-existence of the acceptor levelE _c −E _T = 0.34 eV located in then-side of the junction.     

The effect of temperature on the dynamic characteristics of heat-resistant thermoplastic composites

Two thermoplastic and two thermosetting fibrereinforced plastic composites were subjected to dynamic tests over a wide range of temperature, covering both cryogenic and hot environments. The thermal behaviour of each composite, as indicated by its dynamic mechanical properties, was assessed individually, and was compared collectively with that of the other composites.     

A study of impact toughness of Fe-Cr-X damping alloys

A study was carried out on the impact toughness of Fe- Cr- Х damping alloys. Two measures proved to be effective in improving impact toughness. One was to lower carbon plus nitrogen content to an ultra- low level. This method is suitable for single- phase ferrite alloy. The other is to use dual- phase damping alloys. The presence of martensite in Fe- Cr- Х alloys can enhance impact toughness remarkably, but lower damping capacity drastically. This shows the importance of achieving balance between mechanical prop-erties and damping capacity by properly controlling martensite volume fraction in dual- phase alloys.