镍中氢与缺陷互作用的正电子寿命和多普勒展宽研究

采用正电子寿命和多普勒展宽技术研究了退火、回复及冷轧镍中氢与缺陷的互作用．结果表明：冷轧镍充氢后正电子平均寿命和多普勒展宽S参数上升，并且寿命谱的两成分拟合出现一个390ps的长寿命分量；而退火及回复镍充氢后正电子平均寿命和多普勒展宽S参数均不改变．因此认为冷轧镍充氢后正电子参数（平均寿命和S参数）的上升取决于氢和空位的互作用，与氢和位错的互作用无关；氢空位对也可以作为聚集空位的核心 关键词：     

非晶Nd-Fe薄膜电阻的温度效应与非晶稳定性

用闪光蒸镀法在77K制备了Nd_xFe_1-x(x=0.06-0.80)非晶薄膜,原位测定了其电阻随温度的变化。结果表明:在0.192和ρ(T)∝T。晶化不是在一个固定的温度,而是在一个温度区间发生。     

漫谈金属探测器

提起金属探测器（Metal Detector），人们就会联想到探雷器，工兵用它来探测掩埋的地雷．金属探测器是一种专门用来探测金属的仪器，除了用于探测有金属外壳或金属部件的地雷之外，还可以用来探测隐蔽在墙壁内的电线、埋在地下的水管和电缆，甚至能够地下探宝，发现埋藏在地下的金属物体．目前还广泛应用于各种大型会议中心、会展场馆、体育场馆、公检法、监狱系统及娱乐场所的安全检查和工厂企业的防偷窃检查，甚至用于对高考禁带物品的检查．本文就来谈谈金属探测器的发展历史和工作原弹．     

阴极还原处理对多孔硅发光性能的影响

对经过阴极还原处理后的多孔硅样片进行了光致发光测试和稳定性测试.实验结果表明这种处理能明显改善多孔硅的发光稳定性,使其表面结构更加稳定.利用原子力显微镜对不同还原时间的多孔硅微结构及形貌进行了比较,在一定范围内随着还原时间的增长多孔硅表面粗糙度增大,PL谱增强.     

新型金属杂冠醚配合物18-MC-6[Mn6(4-Amashz)6(DMF)6]·12DMF的合成

合成了一种新型金属杂冠醚配合物[Mn6(4-amashz)6(DMF)6]·12DMF,并用X射线衍射法对其结构进行了表征.研究了该化合物修饰金电极催化氧还原的性质,结果表明,该化合物具有平面碟状结构,对在碱性溶液中的氧有显著的催化还原作用.     

养殖池塘沉积物的重金属分布及污染特征

浙江省淅西北地区淡水养殖池塘沉积物重金属调查研究表明，养殖池塘沉积物中7种重金属元素分布不均衡，差异也较大，除Hg和Cr元素外，其余重金属元素已大大超过土壤本底值．虽然其实测含量都未超出国家规定的标准值范围，但沉积物中重金属元素对养殖水环境、养殖品种存在的潜在污染与危害值得关注．污染指数评价显示，养殖池塘沉积物中主要污染物质为Cu和Cr，而Hg、Pb污染程度相对较轻．     

短脉冲激光辐照下金属镜面波纹损伤机理研究

用脉冲Nd：YAG激光(波长1．06μm、半高宽10ns)辐照了多种金属膜层镜面，用光学与原子力显微镜观察到某些样品损伤区或周围有规律的波纹图案，波纹周期从几微米到几十微米。通过分析实验结果，这里提出了波纹产生的光学模型，认为光路系统中某些元件的衍射或者强光与元件表面相互作用过程中产生的干涉可能会导致元件表面波纹状损伤图案。通过理论计算，初步解释了实验中波纹的周期和其他现象。     

Transmission Properties of THz Radiation Pulses through Very Deep Zero-Order Metallic Gratings

Very deep zero-order metallic grating structures are processed to study the transmission properties of THz radiation pulses. The experiments have been performed with two samples. The delay of the THz pulses and the corresponding resonantly enhanced transmission spectra through the samples are observed. To explain the extraordinary transmission we have treated the samples as Fabry-Perot resonators through resonant excitation of the coupled surface plasmon polaritons filled in the cavities between the metal slats. The experimental results are in reasonable agreement with the numerical simulation. Our results show that THz-time-domain spectroscopy may be an effective technique for studying the optical properties of various THz microstructured devices.     

Deformation Morphology underneath the Vickers Indent in Bulk Metallic Glasses

Plastic deformation behaviour of Zr52.5Al10Ni10Cu15Be12.5 and Mg65Cu25Gd10 bulk metallic glasses (BMGs) is studied by using the depth-sensing nanoindentation and microindentation. The subsurface plastic deformation zone of the BMGs is investigated using the bonded interface technique. Both the BMGs exhibit the serrated flow depending on the loading rate in the loading process of indentation. Slow indentation rates promote more conspicuous serrations, and rapid indentations suppress the serrated flow. Mg-based BMG shows a much higher critical loading rate for the disappearance of the serration than that in Zr-based BMG. The significant difference in the shear band pattern in the subsurface plastic deformation zone is responsible for the different deformation behaviour between the two BMGs. Increase of the loading rate can lead to the increase of the density of shear bands. However, there is no distinct change in the character of shear bands at the loading rate of as high as1000 nm/s.     

Unusual Transport Properties near the Insulator-Metal Transition in Colossal Magnetoresistive Manganites

It is argued that a combination of the Griffiths theory and the double-exchange mechanism predicts the random distribution of ferromagnetic metallic clusters above the Curie temperature TC in colossal magnetoresistive manganites. Along this line, we propose a model for the temperature dependence of resistivity that yields a quantitative agreement with experimental data obtained in a typical manganite La2/3Ca1/3MnO3. Our result indicates that the formation and growth of ferromagnetic metallic clusters are responsible for the observation of unusual transport properties near the insulator-metal transition.