Ternary alloying study of MoSi2

Ternary alloying of MoSi₂ with adding a series of transition elements was investigated by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). Iron, Co, Ni, Cr, V, Ti, and Nb were chosen as alloying elements according to the AB₂ structure map or the atomic size factor. The studied MoSi₂ base alloys were prepared by the arc melting process from high-purity metals. The EDS analysis showed that Fe, Co, and Ni have no solid solubility in as-cast MoSi₂, while Cr, V, Ti, and Nb exhibit limited solid solubilities, which were determined to be 1.4±0.7, 1.4±0.4, 0.4±0.1, and 0.8±0.1. Micro-structural characterization indicated that Mo-Si-M_VIII (M_VIII=Fe, Co, Ni) and Mo-Si-Cr alloys have a two-phase as-cast microstructure, i.e., MoSi₂ matrix and the second-phase FeSi₂, CoSi, NiSi₂, and CrSi₂, respectively. In as-cast Mo-Si-V, Mo-Si-Ti, and Mo-Si-Nb alloys, besides MoSi₂ and C40 phases, the third phases were observed, which have been identified to be (Mo, V)₅Si₃, TiSi₂, and (Mo, Nb)₅Si₃.     

Permeation of Zidovudine and Probenecid from Oily Bases Containing Alcohols Through Rat Skin

Permeation of zidovudine (3'-azido-3'-deoxythymidine, AZT) and probenecid from oily bases containing an alcohol through rat skin was examined. Isopropyl myristate (IPM), as an oily vehicle, showed a penetration enhancing effect for AZT and probenecid. Ethanol, n-propanol, and n-butanol were used as additives in IPM and were examined for their own permeation and the enhancing effect on the permeation of AZT and probenecid. The skin permeation of AZT and probenecid from IPM was enhanced by addition of the alcohol in IPM. The degree of the enhancement was decreased with increasing lipophilicity of the alcohol used. me permeation rate of the drug from those systems was shown to be governed by penetration-enhancing effects of the oily base and alcohol, and the penetration of the alcohol itself through the skin.     

内蒙古煤系高岭土作为FCC催化剂基质的研究

研究两种内蒙古煤系高岭土（1^＃、2^＃）的化学组成、晶体结构并与苏州高岭土进行了比较。对三种高岭土进行酸改性，利用BET、吡啶-TPD和微反测试分别研究改性前后高岭土的性能特点。并将内蒙古高岭土1^＃与苏州高岭土采用半合成方法合成了FCC催化剂，测定了其裂化活性。研究结果表明，内蒙古1^＃具有较良好的晶体结构和化学组成，经酸改性后比表面积大大增加，具有合适的孔径分布，裂化活性较好，可以取代苏州高岭土作为FCC催化剂的基质。     

花艺教室：荆丛亦风流

运动的环热烈的爱//圆点示爱//纯洁爱情//心心相印//透过玻璃的美     

安全:爆破工程永恒的主题——2001年重大拆除爆破工程回顾

通过对2001年我国重大拆除爆破工程的回顾,认为在提高大面积毫秒非电起爆网络可靠性,控制爆破震动、扬尘、噪声等环境影响,与机械清理配合,实现快速施工等方面取得了进展与突破;对几起爆破安全事故进行了初步分析.为保证拆除爆破工程安全,在加强理论研究、开展技术创新、建立科学有序的管理制度等方面提出了建议意见.     

吸收雷达波包装材料的研究进展

论述了吸收雷达波包装材料的基本组成及其选择原则，在此基础上讨论了吸波材料的吸波原理及影响吸波性能的因素，并指出了吸波包装材料的开发现状和应用进展及其发展万向。     

实行工程预决算审计 严格控制投资成本

针对目前企业固定资产投资中存在的投资超概算问题 ,论述了实行工程预决算审计的必要性 ,结合江西铜业股份有限公司的实践阐明了如何实行工程预决算审计 ,以达到提高投资效益的目的。     

CSAa黏弹性表面活性剂压裂液的研制

用化学试荆长链烷基季铵盐CSAa制备了两种VES压裂液并研究了相关性能，其组成（CSAa／水杨酸钠／氯化钾／正丁醇，以g／dL为单位）如下：1．0／0．3／1．0／0．2；2．0／0．6／0．5／0．1。在耐温性测定中，1．0g／dL CSAa压裂液的黏度由30℃时的75．0mPa·s降至50℃时的37．5mPa·s；2．0g／dL CSAa压裂液的黏度由40℃时的225mPa·s逐渐降至55℃时的110mPa·s，再降至60℃时的65．0mPa·s.在1701／s剪切2h后，剪切温度为42℃时1．0g／dL CSAa压裂液的黏度下降26％，剪切温度为53℃时2．0g／dL CSAa压裂液黏度下降9％。陶粒沉降速度测定结果表明，40℃、42℃时的1．0g／dL CSAa压裂液（黏度分别为60和54mPa·s）和50℃、53℃时的2．0g／dLCSAa压裂液（黏度分别为180和145mPa·s）携砂性能良好，而45℃、50℃时的1．0g／dLCSAa压裂液和55℃、60℃时的2．0g／dL CSAa压裂液，携砂性能则较差或很差。认为VES压裂液的携砂性能来源于棒状胶束网络，并不全由压裂液黏度决定。还考察了VES压裂液的破胶性能。图1表2参5。     

Ta-2．5W焊接工艺试验研究

通过对Ta-2.5W难熔重金属换热管的一系列焊接工艺试验研究,掌握了钽材的特殊焊接技术工艺和要求,满足了今后制造和修复苯胺装置中硫酸蒸发器管束的需要。