Room temperature ferromagnetism of Ni, (Ni, Li), (Ni, N)-doped ZnO thin films

Ni-doped ZnO thin films (Ni concentration up to 10 mol%) were generated on Si (100) substrates by a sol-gel technique. The films showed wurtzite structure and no other phase was found. The chemical state of Ni was found to be bivalent by X-ray photoelectron spectroscopy. The results of magnetic measurements at room temperature indicated that the films were ferromagnetic, and magnetic moment decreased with rise of Ni concentration. The magnetization of Ni (10 mol%)-doped ZnO film annealed in nitrogen was low...     

基于工作流的设计过程管理系统研究

根据设计过程管理的需要,深入研究了工作流中任务模型,总结了任务3个特点——独立性、集成性、可审核性。为实现任务的审核和保证工作流中文档管理的需要,提出了目标的概念,建立了完整的任务模型,实现了文档的安全性要求和随工作流的传递。基于以上思路,构建了基于Web的设计过程管理系统DPMS。     

时尚门的解决方案

NG对接铰链是Monchengladbach公司的铰链专家Hahn博士的最新产品。这种直径只有20mm的新款铰链作为一个整体与时尚门完全地结合起来。     

多层印制电路板抗快速瞬变脉冲群干扰的电磁兼容性设计

在电力系统继电保护设备中，因为出现系统故障时产生的各种电磁干扰信号既大又复杂，要保证保护设备的正确动作，电磁兼容性设计．特别是控制快速瞬变脉冲群干扰信号对保护设备影响的设计显得非常重要。本文重点讨论控制瞬态干扰的方法、多层电路板布线规则、去耦与旁路、接地技术等。     

Gate oxide punching thru mechanism in plasma dry etching

The punching thru mechanism of gate oxide (thickness about 15A) was investigated. Because of the thin thickness of gate oxide, gate oxide punching thru may easily happen during the plasma process. It was found that what caused the punching thru was not only the selectivity of poly-silicon/oxide but also the pattern topography. We used the basic SRAM pattern to check this topography effect, and found that gate oxide located at the narrow spacing of two parallel serpentine lines was the most easily punched thru. What caused the topography effect was the starvation of oxygen in these places which were induced by the residue of poly-silicon and enhanced by electron shading effect. So, to solve the issue of gate oxide punching thru, firstly the selectivity should be enough, secondly we should pay attention to the etching pattern topography. Supported by the National High-Tech Research and Development Program of China (“863” Project) (Grant No. 2006AA843134) and the National Basic Research Program of China ("973" Project) (Grant No. 2007CB935302)     

Ultralight X-type lattice sandwich structure (I): Concept,fabrication and experimental characterization

A new type of ultra-lightweight metallic lattice structure (named as the X-type structure) is reported. This periodic structure was formed by two groups of staggered struts in the traditional pyramid structure, and fabricated by folding expanded metal sheet along rows of offset nodes and then brazing the folded structure (as the core) with top and bottom facesheets to form sandwich panels. The out-of-plane compressive and shear properties of the X-type lattice sandwich structure were investigated experimentally and compared to those of the sandwich having a pyramidal truss core. It is found that the formation of the 2-dimensional staggered nodes can effectively make the X-type structure more resistant to inelastic and plastic buckling under both compression and shear loading than the pyramidal lattice truss. Obtained results show that the compressive and shear peak strengths of the X-type lattice structure are about 30% higher than those of the pyramidal lattice truss having the same relative density. Supported by the National Basic Research Program of China (“973” Project) (Grant No. 2006CB601202), the National Natural Science Foundation of China (Grant Nos. 10632060,10825210), the National “111” Project of China (Grant No. B06024) and the National High-Tech Research and Development Program of China (“863” Project) (Grant No. 2006AA03Z519)     

砖石建筑过时了吗？

人们说，车轮是人类最伟大的发明。当然很难就此争论其是与非。但是处于第二位的是什么呢？可能不起眼的砖块是竞选者之一。它体积之小，可握于手中，但是数块砖叠砌在一起又是如此的巨大，在太空上用肉眼就可以看到用它们所建造的建筑。诚然，虽说中国的万里长城并不是每一部分都由烧制砖块砌成，但是大部分采用了这种材料。尤其是墙的顶部用灰泥嵌缝并结合恰当，这样就不会有植物从中长出来了。     

Comparison of ablative and compressive mechanical behavior of several PICA-like ablative materials

It is significant to compare the ablative and compressive mechanical behavior of different PICA-like materials in the engineering applications. The plasma wind tunnel ablation tests with high-entropy air and CO_2 atmospheres, and compressive experiments in the ambient and 150℃, were conducted for three kinds of PICA-like materials(CF/PR-Si, CBCF/PR-SiOC and NQF/PR-Si composites). The traditional carbon/phenolic(C/PR) braided composites were also used for comparison. PICA-like materials have the better thermal insulation than traditional C/PR composite, especially for CBCF/PR-SiOC composite. The ablation behavior of CF/PR-Si and CBCF/PR-SiOC PICA-like materials in the CO_2 atmosphere can produce a large amount of SiO_2 in the form of coatings, oxide layers and skeletons on the ablated surface, which are greatly different from that in the air atmosphere.The compressive behavior of PICA-like material is greatly depended on the fiber fabrics, and exhibits the large discrete characteristics. The longer fiber in the PICA-like materials plays the role in maintaining the material integrity, while it may increase the thermal conductivity.     

优质玻璃纤维门

Jeld-Wen公司最近推出了一种新款户外门：即运用了PUR纤维技术的Jeld-Wen优质玻璃纤维门。这些门的外壳由拜耳材料科学公司特定的聚氨酯材料制剂铸造而成。拜耳材料科学公司与Jeld-Wen公司紧密合作，从Baytec SPR喷雾聚氨酯和Baydur STR聚氨酯发展而得到了一种应用于此的制剂。使用这些聚氨酯材料增强了门的空间稳固性，并使其具有更好的强度和防碰撞能力。     

混凝土减缩剂的作用机理及应用

混凝土干燥收缩主要是胶凝材料中含有多余水量蒸发的结果。本文简述了减缩剂的发展历程，阐明了减缩剂的作用机理，并分析了减缩剂的产品技术优势及作用效果。