TiO2薄膜光催化降解二氯乙酸和三氯乙酸水溶液

用常压化学气相沉积法镀TiO2薄膜,以紫外灯为光源,对二氯乙酸和三氯乙酸溶液进行光催化降解,并证实了此过程符合一级反应动力学方程。结果表明:卤代度以及不同的半导体化合物底物均对二氯乙酸和三氯乙酸溶液的降解有影响,卤代度低的二氯乙酸比卤代度高的三氯乙酸降解效果要好;同样条件下半导体的带隙能越低,降解效果越好。     

超声波法合成三烷基硼及其裂解制备碳化硼

在超声波作用下采用一步合成法分别制备三乙基硼、三丙基硼和三丁基硼;考察超声波作用对合成产物产率的影响,用红外光谱及元素分析表征合成产物的结构;以合成的三乙基硼、三丙基硼和三丁基硼为原料通过热裂解制备纯度较高的碳化硼超硬材料;讨论不同原料和裂解温度对合成产物中C含量的影响.研究结果表明:以三乙基硼为原料在温度为1 400K进行裂解时,其裂解产物中B4C,B2O3和裂解自由碳的含量分别为94.0%,2.2%和3.8%.     

硅表面双聚体空位附近原子沉积的理论研究

采用经验紧束缚近似方法模拟重构硅(100)表面单个双聚体空位(SDV)附近的单个硅原子的沉积行为，根据绘制的SDV附近附加能量差异的三维及投影图，确定了沉积束缚点和一些鞍点，并研究其可能的扩散路径。     

脉冲激光沉积法制备氧化铋薄膜及其电化学性质研究

首次采用355nm脉冲激光沉积在不锈钢基片上制备了氧化铋薄膜，X—射线衍射(XRD)测试表明在基片温度为300℃，沉积时间为0．5h制备得到的Bi2O3薄膜具有四方结构，SEM和Raman光谱测定对该Bi2O3薄膜的表面形貌和锂化前后的结构进行了表征，结果表明薄膜由小于100nm针状晶粒组成，锂化后的产物可能是LixBi2O3。此外，由电位阶跃法测定了上述Bi2O3薄膜电极的锂离子扩散系数。电化学测定表明，上述Bi2O3薄膜具有充放电循环性能,在电压范围为0．70～3．5V，该氧化铋薄膜在充放电速率为2C时的比容量大约为100mAh／g，并且保持经100次以上充放电循环而没有明显的衰减。     

金属基体表面热熔敷玻璃涂层耐蚀性研究

利用斑点试验、点蚀试验、电化学测试及扫描电镜等方法 ,研究了熔敷温度、保温时间和稀土添加量等工艺参数对热熔敷法制备的玻璃涂层耐蚀性的影响 ,探讨了添加稀土提高玻璃涂层耐蚀性的机理。试验结果表明 ,采用热熔敷法制备的玻璃涂层有较好的耐蚀性。随着熔敷温度的提高和保温时间的延长 ,形成了一定量的晶相后会降低涂层的耐蚀性。试验结果表明 ,熔敷温度为 70 0℃、保温 5min后能够得到耐蚀性良好的玻璃涂层。添加稀土提高了釉料的软化温度和熔融釉料的粘度 ,阻止了结晶形核和晶核长大 ,减少了晶相 ,同时提高了涂层的电极电位 ,使涂层耐蚀性显著提高。当稀土含量为 2 %时 ,涂层的耐蚀性较好。     

从黄土Sr同位素探讨海水87Sr/86Sr变化的原因

目前多数认为河流输入是引起海水^87Sr／^86Sr变化的最主要因素，对此推论并没有提供确实的定量分析和依据．通过对黄土高原洛川剖面黄土—古土壤Sr同位素组成和沉积速率等的定量计算说明，在过去2．5Ma期间，海水^87Sr／^86Sr上升总量仅是河流输人海洋总量的大约1/10，而其9／10被海底玄武岩的热液蚀变输入所抵消．海底玄武岩的热液蚀变输入对海水^87Sr／^86Sr变化的总影响量应近似等于河水输入对海水^87Sr／^86Sr变化的总影响量．海水^87Sr／^86Sr变化的原因是河水输入与海底玄武岩的热液烛变输入联合作用的结果．     

HV/CVD Grown Relaxed SiGe Buffer Layers for SiGe HMOSFETs

High-vacuum/chemical-vapor deposition (HV/CVD) system was used to grow relaxed SiGe buffer layers on Si substrates. Several methods were then used to analyze the quality of the SiGe films. X-ray diffraction and Raman spectroscopy showed that the upper layer was almost fully relaxed. Second ion mass spectroscopy showed that the Ge compositions were step-graded. Transmission electron microscopy showed that the misfit dislocations were restrained to the graded SiGe layers. Tests of the electrical properties of tensile-strained Si on relaxed SiGe buffer layers showed that their transconductances were higher than that of Si devices. These results verify the high quality of the relaxed SiGe buffer layer. The calculated critical layer thicknesses of the graded Si1-xGex layer on Si substrate and a Si layer on the relaxed SiGe buffer layer agree well with experimental results.     

Evolution of the South China Sea and monsoon history revealed in deep-sea records

As the third summary report of ODP Leg 184 to the South China Sea (SCS), this paper discusses the evolution of the East Asian monsoon and the SCS basin. A multi-proxy approach, involving geochemistry, micropale-ontology, pollen and other analyses, was adopted for reconstructing the evolutionary history of the East Asian monsoon, which was characterized by a series of paleo-climate events especially at 8, 3.2, 2.2 and 0.4 Ma. The new record indicates similar stages in the development of the East and South Asian monsoons, with an enhanced winter monsoon over East Asia being the major difference. The rich spectrums of monsoon variability from the southern SCS also reveal other characteristic features of the low latitude ocean. Evidence for the evolution of the SCS includes the hemipelagic Oligocene sediments, implying the existence of deep water environments during the early seafloor spreading stage of the SCS basin. The four major unconformities and some remarkabl ediagenetic features in upper Oligocene deposits indicate the strongest tectonic events in the region. From a careful comparison of lithologies and sedimentation rates, we conclude that the prominent differences in sedimentary environments between the southern and northern SCS were established only by ～3 Ma.     

Ni-Fe-P合金化学镀的工艺条件及晶化行为研究

采用硼酸为缓冲剂,柠檬酸钠为络合剂在碱性介质中化学沉积Ni Fe P合金.考察了工艺条件如pH、FeSO4·7H2O浓度和温度对沉积速度的影响.获得了沉积速度快,镀液稳定性好的工艺条件.采用差示扫描量热和X射线衍射研究了Ni Fe P合金的晶化行为.结果表明,镀层在镀态呈非晶结构,镀层在200.5℃晶化为亚稳的Ni Fe合金,310℃晶化为立方FeNi3合金,369.2℃晶化为四方的Ni3P,而491.3℃为继续生成FeNi3的吸热峰.     

论在经济交往中盗赃物的善意取得

善意取得制度是民法的一项重要制度，受物权法调整。我国现行立法对善意第三人的权益保护不周，尤其是在刑事司法实践中，善意占有人的权益常常受到侵害。我国善意取得制度立法宜采“中间法立场”，兼顾所有权保护与交易安全，对盗赃物等占有脱离物，在立法技术上，采“例外规定主义”。