离子束淀积方法制备GdSi_2薄膜

采用离子束淀积方法制备了单相GdSi2薄膜.用俄歇电子谱仪对样品的成分进行了分析,用X射线衍射方法分析了样品的结构,并用扫描电子显微镜观察了样品的表面形貌.X射线衍射分析发现在400℃沉积的样品中仅存在正交的GdSiz相.样品在氩气氛中350C,30min退火处理后,GdSi2相衍射峰的半高宽变窄,说明经过退火处理,GdSi2的晶体质量变得更好.

不同LET ~(12)C~(6+)离子对生防菌BJ1的辐射诱变效应

选取高低两个LET点(40和60keV/m),剂量点分别为50,100,200,400,600Gy进行辐照处理,研究了生防菌的存活率与突变率的关系,抑菌谱以及活性等。结果表明,在高LET条件下,低剂量辐照就可以得到较多的突变体,并且BJ1有较高的存活率和突变谱,有利于筛选优良的正突变体。因此高LET较低LET有更为明显的辐射诱变效应。

高温高压下水热体系中黄铁矿-金原电池的腐蚀电化学原位测量研究

水流体-导电性矿物相互作用是自然界中水流体-固体相互作用的重要组成部分，是许多矿床形成和演化的核心过程。迄今为止，绝大多数地质和地球化学家们对导电性矿物在水流体中的溶解机制普遍存在模糊的认识，认为水流体中导电性矿物的溶解和定位是一种简单的化学溶解和沉淀或简单的氧化溶解和还原定位过程，而实质上导电性矿物（组合）在水流体中的溶解是一种由电极电位差驱使下的类似于金属腐蚀的复杂电化学过程。当具有不同电极电位的矿物在溶液中相互接触，就会形成短路原电池发生电化学腐蚀。其中，电极电位低的矿物作为原电池的阳极，其溶解会加剧，而电极电位高的矿物作为原电池的阴极，其溶解会受到抑制。鉴于前人对水流体-导电性矿物相互作用的腐蚀原电池反应机理的模糊认识，本论文工作基于腐蚀原电池观点对高温高压条件下NaCl水流体体系中黄铁矿与金之间的原电池反应进行了研究。 在本工作中，作者与所在的研究小组一道，首先自行研制了一套可用于高温高压水热体系中导电性矿物腐蚀电化学原位测量的高压釜反应装置。该装置主体部件选用在高温高压下具有高强度、抗腐蚀等优良性能的工业纯钛制成。在该装置中，通过将热电偶直接插入高压釜釜腔内，成功地实现了釜内流体温度的准确测量和精确控制。对高压釜不同部位的测温结果表明，沿高压釜的径向与轴向均存在显著的温度梯度，其中釜塞保护锥体处的温度比釜内流体的温度低约8℃，釜外壁中心处与釜内的温度差约10℃；对400℃保温条件下釜内流体温度的直接测量表明，釜内温度波动小于0.5℃。在该装置中，通过将脆性导电性矿物制作成锥形电极，采用耐高温无机绝缘材料制作密封部件，利用锥体自紧式密封技术，成功地解决了脆性电极和电极引线的高压密封与高温绝缘问题；通过引入另一根辅助性的矿物电极引线，成功地解决了原位监测实验过程中矿物电极与引线接触处是否进水的难题，确保了实验的可信度。可行性试验结果表明，该方法不仅可用于高温高压下水流体-导电性矿物，而且可广泛用于水流体-金属间相互作用的腐蚀电化学原位测量研究。 利用上述自行研制的腐蚀电化学实验装置，本工作对高温高压（250-400℃；10-35 MPa）NaCl水流体体系中黄铁矿-自然金原电池的热力学和动力学进行了实验研究。原位测量结果表明： （1）黄铁矿-金原电池的腐蚀电流变化与其开路电压的变化一致； （2）汽-液平衡条件下，黄铁矿-金原电池的开路电压和腐蚀电流在液相中比在汽相中要大； （3）在温度为400 C、压力远离临界点的过热蒸气和超临界区域，压力在实验研究的范围内（10-35 MPa）对黄铁矿-金原电池的开路电压和腐蚀电流均无显著的影响，随压力的增加两者仅略有增大，但当温度压力跨越临界点时，包括温压从汽-液平衡曲线同时进入超临界区以及温度恒定在400 C、压力跨越临界点时，黄铁矿-金原电池的开路电压和腐蚀电流在临界点附近均发生突变。 （4）在本工作中实验的温度、压力和水流体体系条件下，由黄铁矿与金构成的原电池在大多数情况下黄铁矿为阳极，因此在原电池短路时黄铁矿在水流体中发生氧化溶解，而金则为阴极，在原电池短路时金的溶解受到保护，仅在个别狭窄的温度压力范围内情况才相反。 上述原位测量结果与电极表面水流体的性质以及黄铁矿和金的能带结构密切相关，运用混合电位理论、Butler-Volmer方程以及半导体电化学的波动能级模型对实验结果能进行很好的解释。

扬子地块西南缘卡林型金矿床成矿流体地球化学研究

扬子地块西南缘是中国甚至世界上独特的、大面积分布的低温热液矿床矿集区,广泛发育Au、Ag、Hg、Sb、As、U、Cu、Pb-Zn以及重晶石、萤石、冰洲石等低温热液矿床,其中不少矿床属大型-超大型矿床规模.以沉积岩为容矿岩石的卡林型金矿(又称微细浸染型金矿),则是该区重要的矿产类型.目前已发现烂泥沟、紫木凼、戈塘、金牙、高龙等大、中型卡林型金矿床6个,小型矿床、矿点(矿化点)近200余处.主要集中分布在黔西南、滇东南和桂西北的交界地区,周边被深(大)断裂带所限,大体呈三角形,俗称"金三角".首先对该区众多的基性-超基性岩浆岩的同位素年代学及其反映的地质背景进行了较系统的研究,选择革挡和八渡(D)、纳哥(P)、烂泥沟和丫他(T)等代表性金矿床,进行了系统的流体包裹体岩相学、显微测温学、单个包裹体的激光Raman、流体包裹体群中的微量元素以及Rb-Sr、He-Ar、同位素组成等研究,获得了大量数据,并拍摄了大量包裹体照片(约400张).该次对该区卡林型金矿成矿流体地球化学的研究,作者认为在以下方面取得一定进展:(1)发现(或证实)了该区卡林型金矿富含C0<,2>相包裹体,并且种类众多,提出了卡林型金矿的成矿作用,经历了流体不混溶的过程(沸腾作用):(2)进一步证实了有机质参与卡林型金矿的成矿过程:(3)证实了盆地超压流体的存在,并提出了卡林型金矿的大规模成矿作用是"盆地超压流体-矿源岩-盆地伸展"耦合的观点.

Detection of streptomycin residues in whole milk using an optical immunobiosensor

The development of an assay for the detection of streptomycin residues in pasteurized whole milk using an optical biosensor (Biacore) is reported. Streptomycin-adipic hydrazide coupled to bovine thyroglobulin was used to produce a sheep polyclonal antibody. The antibody displayed excellent cross-reactivity with dihydrostreptomycin (106%). There was no significant cross-reaction with other aminoglycosides or common antibiotics. Streptomycin was also immobilized onto a CM5 sensor chip to provide a stable, reusable surface. The developed assay permitted the direct analysis of whole milk samples (similar to3.5% fat) without prior centrifugation and defatting. Results were available in 5 min. The limit of detection of the assay was determined as 4.1 ng/mL, well below the European maximum residue limit (MRL) of 200 ng/mL. Repeatability (or coefficient of variation) between runs was determined as 3.5% (100 ng/mL; 0.5 x MRL), 5.7% (200 ng/mL; MRL), and 7.6% (400 ng/mL; 2 x MRL).

TRIPS Agreement and Public Health: An Overview of International Issues

This paper deals with brief overview of the developments of international provisions on IPR related to public health. It discusses flexibilities before and after TRIPS Agreement and difficulties faced by developing countries in implementing TRIPS obligations and protecting public health. Also discussed are the reasons for the Doha Declaration and issues relating to implementation of Para 6 of the Declaration. Discusses the inadequacy in the compulsory licence based approach to solve public health crisis and argues for a more comprehensive approach to find a long term solution to the public health issues

Composition and cure temperature: The influence on properties of final flexible PU cold cure foam parts

Foams are cellular structures, produced by gas bubbles formed during the polyurethane polymerization mixture. Flexible PU foams meet the following two criteria: have a limited resistance to an applied load, being both permeable to air and reversibly deformable. There are two main types of flexible foams, hot and cold cure foams differing in composition and processing temperatures. The hot cure foams are widely applied and represent the main composition of actual foams, while cold cure foams present several processing and property advantages, e.g, faster demoulding time, better humid aging properties and more versatility, as hardness variation with index changes are greater than with hot cure foams. The processing of cold cure foams also is attractive due to the low energy consumption (mould temperature from 30 degrees to 65 degrees C) comparatively to hot cure foams (mould temperature from 30 degrees to 250 degrees C). Another advantage is the high variety of soft materials for low temperature processing moulds. Cold cure foams are diphenylmethane diisocyanate (MDI) based while hot cure foams are toluene diisocyanate (TDI) based. This study is concerned with Viscoelastic flexible foams MDI based for medical applications. Differential Scanning Calorimetry (DSC) was used to characterize the cure kinetics and Dynamical Mechanical Analisys to collect mechanical data. The data obtained from these two experimental procedures were analyzed and associated to establish processing/properties/operation conditions relationships. These maps for the selection of optimized processing/properties/operation conditions are important to achieve better final part properties at lower costs and lead times.

The catastrophic flash-flood event of 8–9 September 2002 in the Gard region, France: a first case study for the Cévennes–Vivarais Mediterranean Hydrometeorological Observatory

The Cévennes–Vivarais Mediterranean Hydrometeorological Observatory (OHM-CV) is a research initiative aimed at improving the understanding and modeling of the Mediterranean intense rain events that frequently result in devastating flash floods in southern France. A primary objective is to bring together the skills of meteorologists and hydrologists, modelers and instrumentalists, researchers and practitioners, to cope with these rather unpredictable events. In line with previously published flash-flood monographs, the present paper aims at documenting the 8–9 September 2002 catastrophic event, which resulted in 24 casualties and an economic damage evaluated at 1.2 billion euros (i.e., about 1 billion U.S. dollars) in the Gard region, France. A description of the synoptic meteorological situation is first given and shows that no particular precursor indicated the imminence of such an extreme event. Then, radar and rain gauge analyses are used to assess the magnitude of the rain event, which was particularly remarkable for its spatial extent with rain amounts greater than 200 mm in 24 h over 5500 km2. The maximum values of 600–700 mm observed locally are among the highest daily records in the region. The preliminary results of the postevent hydrological investigation show that the hydrologic response of the upstream watersheds of the Gard and Vidourle Rivers is consistent with the marked space–time structure of the rain event. It is noteworthy that peak specific discharges were very high over most of the affected areas (5–10 m3 s−1 km−2) and reached locally extraordinary values of more than 20 m3 s−1 km−2. A preliminary analysis indicates contrasting hydrological behaviors that seem to be related to geomorphological factors, notably the influence of karst in part of the region. An overview of the ongoing meteorological and hydrological research projects devoted to this case study within the OHM-CV is finally presented.