95W-Ni-Fe 合金工艺缺陷的 SAM 和 XPS 分析

藉助扫描俄歇探针、Ｘ射线光电子谱等分析了９５Ｗ－Ｎｉ－Ｆｅ合金碳污染和氧化的本质。发现，碳污染试样中碳的化学状态主要为石墨，少量为铁或镍的有机化合物，这些物质的界面富集使材料脆化。钨合金氧化后，氧大量富集于钨／粘结相界面，使沿着该界面的断裂更容易发生。     

自支撑同位素钐靶的制备

一、引言联邦德国重离子研究所的物理实验需要~(154)Sm和~(144)Sm靶,具体要求是:(1)自支撑金属靶,(2)厚度范围为90—110 μg/cm~2,(3)靶厚测量误差为±10%,(4)靶的尺寸是φ15 mm,(5)靶的数量为4—5块。用滚轧法、电镀法和重离子溅射法制备这样薄的自支撑靶都十分困难,因此采用真空蒸发试制同位素钐靶。     

卤化银探测器及其某些特性

文中简述了卤化银(主要是溴化银)单晶片的某些特性,氯化银单晶片与此大致相似。作为低温晶体探测器,对~(241)Am-α放射源,分辨率为17%。卤化银晶片是固体电解质,只有Ag离子对输出电信号有贡献,有显著的极化现象。在液氮槽内溴化银晶片的电导率在几个数量级内成为可控的,由在室温下外加偏置电压大小所引起的分解状态下的初始电流决定。     

川东二叠系生物礁油气藏的地震勘探技术

 生物礁油气藏是一种特殊的岩性油气藏，由于其地质特点的多样性和复杂性，使得生物礁的地震勘探难度很大。本文针对川东地区二叠系生物礁的地质特点和资料情况，以生物礁气藏为研究对象，从已知井井震响应特征分析出发，通过地震反射结构分析、神经网络波形分类处理、地震属性分析、三维可视化解释、多参数地震反演等多项地震特殊处理和解释方法，建立了生物礁和生物礁储层的判别模式，形成了有针对性的地震勘探配套技术。其中以伽马、补偿中子及声波为目标曲线的多参数地震反演技术对于预测和评价生物礁特别有效。     

高放废液中^126Sn的放化分析

以甲基异丁基酮(MIBK)萃取为主要步骤,放化分离高放废液中的~(126)Sn。全流程化学回收率约为60%。以SnO_2形式制成测量源,用HPGe γ谱仪测取γ谱图,由~(126)Sn的子体特征γ能峰面积,经化学回收率、探测效率校正后,计算得到高放废液中~(126)Sn的含量为371±29 Bq/ml。~(126)Sn的放射性活度约为高放废液总活度的4×10~(-7)。     

Public–Private Partnerships in the Water Sector: The Case of Desalination

Water Resources Management - Public–private partnerships (PPPs) have grown in popularity as a method to leverage private sector actors in the production of government services. With the...     

Nd_2(Fe_(0.9)Si_(0.1))_(14)B的中子衍射研究SCIEI

本文用中子衍射对Nd_2(Fe_(0.9)Si_(0.1))_(14)B在室温及77K进行了测量,用衍射峰的形状分析法进行了数据拟合。结果表明,在室温,Si择优占据4c,8j_1及16k_2晶位;Nd与Fe的磁矩平行于C轴排列。在77K,Si仍择优占据上述三个晶位。算得的Nd磁矩的方向偏离C轴37.8°。     

Inside this month

This issue contains a preview of the CFA’s annual trade show, which this year takes place in Anaheim, California. Those of you who also attend the JEC Composites Show in Paris will see a vast difference between these two events, not only in cultural terms but also in focus. CFA is an association for US manufacturers and its show places a high emphasis on education and networking. JEC’s slant is to the end-user and it strives to be a showcase for composites technology. Both of these approaches are to the ultimate benefit of the composites industry, but as companies continue to look at ways of spending their money more effectively, show attendance is one area coming under increasing scrutiny. Many have been saying that it is too expensive to attend JEC every year and now a group of major resin suppliers, including DSM, Reichhold, Ashland and Cray Valley, have taken the step of staying away from next year’s show (see page 64). This will surely dent the show’s profits and it will be interesting to see how the organisers, as well as other exhibitors, will respond to this development.     

Mutation of herpesvirus thymidine kinase to generate ganciclovir-specific kinases for use in cancer gene therapies

Understanding the functional and mechanistic properties of themulti-substrate herpes simplex virus type-1 thymidine kinase(HSV-1 TK) remains critical to defining its role as a majorpharmacological target in herpesvirus and gene therapies forcancer. An inherent limitation of the activity of HSV-TK isthe >70-fold difference in the K_ms for phosphorylation ofthymidine over the pro-drug ganciclovir (GCV). To engineer anHSV-1 TK isoform that is specific for GCV as the preferred substrate,16 site-specific mutants were generated. The mutations wereconcentrated at conserved residues involved in nucleoside basebinding, Gln125 and near sites 3 and 4 involved in catalysisand substrate binding. The substrate preferences of each mutantenzyme were compared with wild-type HSV-1 TK. One mutant, termedQ7530 TK, had a lower K_m for GCV than thymidine. Expressionof the Q7530 TK in tumor cells indicated comparable metabolismto and improved sensitivity to GCV over wild-type HSV-1 TK,with minimal thymidine phosphorylation activity. A molecularmodeling simulation of the different HSV-1 TK active-sites wasdone for GCV and thymidine binding. It was concluded that mutationsat Gln125 and near site 4, especially at Ala168, were responsiblefor loss of deoxypyrimidine substrate binding.     

Effect of DAG on milk fat TAG crystallization

The effect of milk fat and standard DAG on the crystallization behavior of milk fat TAG (MF-TAG) was investigated. When milk fat DAG were added to MF-TAG at the 0.1 wt% level, crystallization was delayed. Racemic purity was shown to be an important factor in the ability of DAG to influence TAG crystallization. Only sn-1,2 isomers of blends of MF-TAG with 0.1 wt% of the racemic mixtures of dipalmitin and diolein increased the activation free energy barrier to MF-TAG nucleation (ΔG _c ) and delayed the subsequent crystallization process by increasing the crystallization induction time (τ_SFC) determined from solid fat content-time measurements. Although crystallization kinetics were affected, the properties of the resulting network structures remained unchanged upon addition of milk fat minor components at the 0.1 wt% level