Crystalline mesoporous metal oxide

Since the discovery of many types of mesoporous silicas, such as SBA-15, KIT-6, FDU-12 and SBA-16, porous crystalline transition metal oxides, such as Cr2O3, Co3O4, In2O3, NiO, CeO2, WO3, Fe2O3 and MnO2, have been synthesized using the mesoporous silicas as hard templates. Several synthetic methods have been developed. These new porous materials have high potential applications in catalysis, Li-ion rechargeable batteries and gas sensors. This article gives a brief review of the research of porous crystals of metal oxides in the last four years.     

Antibodies against metal chelates

Because monoclonal antibodies can recognize and bind to specific groups of atoms such as tumour antigens, they have promise for use in vivo as carriers of radionuclides, drugs or other appended molecules for diagnosis and treatment of disease. Attachment of metal ions to antibodies by means of bifunctional chelating agents can add the diverse nuclear, physical and chemical properties of the metallic elements to these specific binding proteins (ref. 4 and refs therein). With the ultimate aim of engineering probe-binding properties into the antibodies themselves, we have now prepared monoclonal antibodies against the EDTA chelate of indium. These antibodies show a remarkable preference for indium chelates; changing to another metal such as scandium or gallium can decrease the antibody-binding constant by more than three orders of magnitude. These antibodies also introduce a new degree of control over the biological distributions of chelated radionuclides, markedly altering their uptake in tumours and normal organs.     

碱金属及碱土金属元素性质的多元分析

通过对碱金属及碱土金属元素的键参数、拓扑指数与其物理化学性质的多元回归分析,得到了良好的结构与性质相关性.     

Pillared layered transition metal oxides

This paper reviews the reecent progress in the synthesis and application of pillared transition metal oxides during the last decade ,mainly concerning the synthetic methods,structures ,physical properties and catalytic appli-cations of the laycred transition metal oxides pillared by inorganic oxides,The factors and their affecting regularity in the process of preparation,and some important results obtained in the catalytic application studies are summarized.Finally,a prospect on the potential new directions in this research area is presented.     

金属Al,Cu在激波作用下的变异

分别对Al,Cu等纯金属作了激波处理实验，发现样品的形貌以及内部结构都发生了明显的变化，并对此进行了初步讨论。     

泡沫金属的热分析

提出了一种高孔隙率开孔泡沫金属的结构简化几何模型,运用热电比拟理论在胞孔尺度上分析并求解了有效热导率的计算表达式,并根据已有实验数据进行模型修正.同时模拟分析了金属泡沫三维矩形通道内空气流动的对流换热情况,与实验结果进行了对比验证.研究表明,本文提出的胞孔有效热导率修正模型对铝泡沫金属有一定的适用性;相同孔隙率条件下,泡沫金属通道内强制对流的对流换热系数随孔密度的增加(即孔径的减小)而增大,但付出的代价是阻力也随之增大;相对而言,低孔密度的泡沫金属具有较好的对流换热综合性能.     

AuSi 液态金属离子源

为了进行Ｓｉ聚焦离子束微细加工技术的研究，研制了ＡｕＳｉ液态金属离子源制备设备及其分析设备，制成了实用化的ＡｕＳｉ合金源，得到了制备该合金源的成熟工艺，利用Ｅ×Ｂ质量分离器分离出Ａｕ和Ｓｉ离子束，对源的一些特性如电流—电压曲线、加热功率—发射电流曲线、束流质谱及源的寿命作了分析。该源结构采取同轴针型，合金槽的材料为钼，发射尖为钨丝。源正常工作时的加热方式为间接加热式。该源与带质量分离器的聚焦离子束系统结合，将迈开亚微米Ｓｉ离子束加工的第一步。并为今后研究其它合金源提供经验。     

金属铸造成形综合实验

论述了金属铸造成形综合实验的内容、过程和教学效果,指出教学实验与生产实际相结合是培养新世纪创新人才的良好途径.     

金属V带结构的发展

将金属V带的发展划分为三个阶段；阐述了金属V带结构在变化发展中的各个重要影响因素，并说明了这些因素与金属带性能之间的关系；简单地论述了金属V带现状，得到了一些结论。     

Bias polarity-sensitive electrical failure characteristics of ZnSe nanowire in metal–semiconductor–metal nanostructure

The effect of bias polarity on the electrical breakdown behavior of the single ZnSe nanowire(NW) in the metal–semiconductor–metal(M–S–M)nanostructure under high current density and high bias conditions has been studied in the present paper. The experimental results show that the failure of the ZnSe NW in M–S–M nanostructure was sensitive to bias polarity since the NW commonly collapsed at the negatively biased Au metal electrode due to high Joule heat produced in NW at the reversely biased Schottky barrier. Thus, the electrical breakdown behavior of the ZnSe NW was highly dominated by the cathode-controlled mode due to the high resistance of the depletion region of ZnSe NW at the reversely biased Schottky contact.     

Preparation of PZT thin films by magnetron sputtering with metal and metal oxide composite target

This article mainly deals with the preparation and properties of PZT thin films. A new type of Metal-Metal Oxide composite target was developed. Relating factors have been discussed. The electrical and optical properties of PZT thin films have also been studied. Zhou Zhenguo: born in Feb. 1939, Associate professor. Current research interest is in thin film material Supported by the National Natural Science Foundation of China     

地板及金属板加载对轴向模螺旋天线辐射特性的影响

轴向模螺旋天线是一种常见的圆极化辐射的定向天线,其辐射方向主要是沿着螺旋线的轴线方向。通过改变天线地板的尺寸可以对天线的辐射方向进行调整,使之向地板一侧进行辐射,并能够获得较好的圆极化与定向辐射特性。通过轴向辐射方向的金属板加载,可以显著地提高天线的增益。以一个传统的轴向模螺旋天线为例,对上述两种控制天线辐射效果的方法进行了仿真与实验研究,结果表明减小地板直径可以使天线辐射向着地板方向,并且能够达到约10 d B的前后比;在天线轴向的加载地板可以使天线增益提高1 d B以上,并且对天线的阻抗带宽及圆极化特性等性能影响较小。上述方法的采用可以使得轴向模螺旋天线的应用更加广泛。     

提高金属铭牌粘接可靠性

本文蛄合工作实际,针对产品金属铭牌粘接工艺进行研究,并对粘接过程的控制要求进行了较为详尽地阐述,从而对提高产品金属铭牌可靠性提供技术支持。     

Gas-sensing properties of nanocomplex metal oxide

The development of CuOCeO2 nanocomposites as the sensing material of semiconductor gas sensors is reported. CuOCeO2 nanocomplex oxide is prepared by modified sol-gel method that uses copper nitrate, cerium nitrate and ethylene glycol as precursors. The optimized synthesis parameters and processing condition have been established. The particle size and distribution, phase morphology, specific surface, electronic states of atoms and gas sensing properties have been systematically characterized by Transmission Electron Microscope (TEM), Brunauer Emmett Teller (BET), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and gas sensitivity measurement. The results show that the sensor sensitivity depends on particle size, CuCe cation ratio and calcination temperature. The effects of calcinations temperature and CuO loading on the gas sensitivity are also examined. The optimum calcination temperature and the CuO content for the highest sensitivity are 600 ℃ and 12%, respectively. The combination of excellent thermal stability and tunable sensing properties through careful control of the processing parameters and selection of material composition gives rise to novel nanocomposites attractive to the sensitive and selective detection of a variety of toxic and combustible gases.     

Low-energy acoustic plasmons at metal surfaces

Nearly two-dimensional (2D) metallic systems formed in charge inversion layers and artificial layered materials permit the existence of low-energy collective excitations, called 2D plasmons, which are not found in a three-dimensional (3D) metal. These excitations have caused considerable interest because their low energy allows them to participate in many dynamical processes involving electrons and phonons, and because they might mediate the formation of Cooper pairs in high-transition-temperature superconductors. Metals often support electronic states that are confined to the surface, forming a nearly 2D electron-density layer. However, it was argued that these systems could not support low-energy collective excitations because they would be screened out by the underlying bulk electrons. Rather, metallic surfaces should support only conventional surface plasmons-higher-energy modes that depend only on the electron density. Surface plasmons have important applications in microscopy and sub-wavelength optics, but have no relevance to the low-energy dynamics. Here we show that, in contrast to expectations, a low-energy collective excitation mode can be found on bare metal surfaces. The mode has an acoustic (linear) dispersion, different to the dependence of a 2D plasmon, and was observed on Be(0001) using angle-resolved electron energy loss spectroscopy. First-principles calculations show that it is caused by the coexistence of a partially occupied quasi-2D surface-state band with the underlying 3D bulk electron continuum and also that the non-local character of the dielectric function prevents it from being screened out by the 3D states. The acoustic plasmon reported here has a very general character and should be present on many metal surfaces. Furthermore, its acoustic dispersion allows the confinement of light on small surface areas and in a broad frequency range, which is relevant for nano-optics and photonics applications.     

Special issue on toxic metal pollution

Metals and metalloids are an integral part of the Earth’s crust.Some of these elements are of great concern due to their high toxicity and threat to humans,wildlife,and the ecosystem.For simplicity,the term toxic metals is adopted to represnt both