英语专业八级阅读水平的制约因素及训练对策

英语专业八级测试中的阅读部分因难度高、题量大而成为影响考生八级通过率的重要因素之一。英语阅读的解题能力由英语阅读水平决定，而英语阅读水平则取决于英语理解知识、理解技能及图式结构。八级阅读的制约因素在于六级以上的词汇量、高层次的阅读策略及背景知识的广泛程度。针对学生现状与八级阅读要求的差距，只有既进行强化答题能力训练，又抓好系统化的全面拓展阅读能力培养，才能真正促进教学、提高八级通过率。     

纳米CeO2和Co3O4粉体的合成

用甲酸代替水作反应介质,以六水合硝酸亚铈为原料,采用非水溶剂水热法制备纳米CeO2;以六水合硝酸亚钴为原料,碳酸铵为沉淀剂,采用均相沉淀法在不同反应条件下,合成纳米Co3O4.用XRD,TEM,BET等手段测定产品的形貌和纳米尺度.实验表明,所合成的CeO2,Co3O4,粒径大小分别在10～20nm和20～30nm范围.该材料作为镍氢电池负极添加剂,大大改良电池的低温放电性能,增加可充电次数.     

憎水性纳米银粒的反相微乳液法制备与自组装

利用十八胺/正丁醇/正庚烷/甲酰胺/A gNO3(aq)构成的W/O型微乳液体系,在回流状态下由甲酰胺还原银离子制得了十八胺稳定的憎水性银纳米粒子,并通过UV-V is、TEM和XRD等手段对样品进行了表征.所制十八胺包裹的银纳米颗粒粒径分布较宽,且粒子形成了大、小尺寸的两个集团,在自组装试验中大、小粒子分别位于单层膜的中心和边缘地带.     

Formation mechanism of ferromagnetic minerals in loess of China： TEM investigation

The results of TEM investigation indicate that magnetite and maghemite are the major ferromagnetic minerals in loess-paleosol sequences. Primary magnetite has the similar morphology and surface characteristics as eolian detrital particles. The magnetite can be classified into two categories, high-titaninm and low-titanium, which may be the indicators of magmatic rocks and metamorphic rocks,respectively. TEM investigation at nanometer scale shows that primary detrital magnetite of micron scale had been partially weathered to magnetite of 5-20 nanometer during the pedogenic process, which maintain the pseudomorphism of the aeolian debris. Some chlorite particles were also weathered to nanometer scale magnetite or maghemite in the pedogenic process. So weathering of the two minerals leads to formation of superparamagnetism, which may be the important mechanism of magnelic-susceptibnlty increase in paleosols. The mgnelite or maghhemite resulting from the weathering of chlorite contains a small amount of P and S,which is the signal of microbe-mineral interaction, and indicates that microbes may play a certain role in chlorite weathering and formation of Superparamagnetic particles.     

镍基高温合金长期时效后γ′相长大动力学

采用TEM观察,相分析,图像分析等实验方法,对合金在873～1173K分别经100～1000h长期时效处理,研究了γ′相的长大动力学·结果表明,γ′相随温度的升高和时间的延长明显长大,但温度的影响比时间更为明显·在一定温度下随时间延长其长大规律符合里夫希茨·瓦格纳的成熟理论:r3与t成正比,γ′相长期时效的长大速率相对于时效初期的长大速率较慢,组织比较稳定·根据试验结果利用作图法得出合金的扩散激活能为241 54kJ·mol-1·     

Transmission electron microscopy study on microstructure in Langmuir-Blodgett films of fullerene derivatives

Surface pressure-area isotherms of two C₆₀ derivatives, ethoxycarbonyldecylentfullerene and bis(ethoxycarbonyldecylene) fullerene, have been investigated. The molecular aggregation at the air-water interface was reduced and the transfer behavior to various substrates was enhanced as compared with those of pure C₆₀. Structural characterization of the LB films was carried out using high resolution transmission electron microscopy (HRTEM). The HRTEM images revealed regular stacking of the densest packed rows of molecules in the LB films.     

非晶态半导体多层膜的TEM及HREM研究

本文介绍了非晶态半导体多层膜剖面电镜样品的一种制备方法.报导了周期性调制和准周期性调制的非晶态半导体多层膜的剖面透射电子显微像和其对应的电子衍射花样的性质.通过高分辨电子显微像,研究了组成多层膜的子层材料的微观结构特性和异质结的界面性质.     

西藏基性麻粒岩中的流体和熔融包裹体

用TEM对西藏喜马拉雅变质核杂岩基性麻粒岩中亚微米级、纳米级(粒径在20～500 nm之间)矿物包裹体的超微构造特征研究发现,流体包裹体的的精细结构、分布状态及化学特点等对于研究与麻粒岩有关的下地壳韧性剪切带形成、构造演化及其大陆动力学具有重要的意义.     

加热工艺对含Nb汽车用微合金钢组织及性能的影响

在实验室及工业生产条件下研究加热工艺对含Nb汽车用微合金钢显微组织和力学性能的影响。用THERMECMASTOR-Z型热模拟实验机、光学显微镜及电镜分析及测定该钢种在不同加热条件下的奥氏体组织状态及碳化物析出状态，为合理制定热加工工艺提供了理论依据。     

Transmission electron microscopy and atomic force microscopy characterization of nickel deposition on bacterial cells

Recently bacterial cells have become attractive biological templates for the fabrication of metal nano- structures or nanomaterials due to their inherent small size, various standard geometrical shapes and abundant source. In this paper, nickel-coated bacterial cells (gram-negative bacteria of Escherichia coli) were fabricated via electroless chemical plating. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) characterization results reveal evident morphological difference between bacterial cells before and after deposition with nickel. The bare cells with smooth surface presented transverse outspreading effect at mica surface. Great changes took place in surface roughness for those bacterial cells after metallization. A large number of nickel nanoparticles were observed to be equably distributed at bacterial surface after activation and subsequent metallization. Furthermore, ultra thin section analytic results validated the presence and uniformity of thin nickel coating at bacte- rial surface after metallization.