微波线性相位环状微带滤波器

介绍了一种结构新颖、插入损耗小,且具有优异线性相位的环状微带线滤波器。该滤波器采用数个环形谐振器平行耦合,而输入输出馈线与环形谐振器之间采用直接耦合。文中列举了中心频率为8.6GHz的三环、四环和五环三种不同的滤波器,并对其进行了仿真模拟和结果比较。     

用于高压ESD保护的LDMOS中触发电压退化效应的研究

The trigger voltage walkin effect has been investigated by designing two different laterally diffused metal-oxide-semiconductor （LDMOS） transistors with an embedded silicon controlled rectifier （SCR）. By inserting a P＋ implant region along the outer and the inner boundary of the N＋ region at the drain side of a conventional LDMOS transistor, we fabricate the LDMOS-SCR and the SCR-LDMOS devices with a different triggering order in a 0.5/zm bipolar-CMOS-DMOS process, respectively. First, we perform transmission line pulse （TLP） and DC-voltage degradation tests on the LDMOS-SCR. Results show that the trigger voltage walk-in effect can be attributed to the gate oxide trap generation and charge trapping. Then, we perform TLP tests on the SCR-LDMOS. Results indicate that the trigger voltage walk-in effect is remarkably reduced. In the SCR-LDMOS, the embedded SCR is triggered earlier than the LDMOS, and the ESD current is mainly discharged by the parasitic SCR structure. The electric potential between the drain and the gate decreases significantly after snapback, leading to decreased impact ionization rates and thus reduced trap generation and charge trapping. Finally, the above explanation of the different trigger voltage walk-in behavior in LDMOS-SCR and SCR-LDMOS devices is confirmed by TCAD simulation.     

FeS2薄膜的制备和性能

研究了不同热硫化条件下用纯Ｆｅ膜反应形成的ＦｅＳ２多晶薄膜成分、结晶形态和电阻率的变化规律，结果表明，在４００℃等温２０～３０ｈ时，生成的ＦｅＳ２比较充分，薄膜中的Ｆｅ、Ｓ含量接近ＦｅＳ２计量成分，随硫化温度升高，ＦｅＳ２晶粒明显增大，电阻率显著上升，当在４００℃硫化充分形成ＦｅＳ２晶粒后，继续延长等温时间对组织形态无明显影响。     

纳米碳管的制备及生长机理的研究进展

纳米碳管的研究是纳米材料研究的一个新领域，综述了纳米碳管的研究发展，主要是纳米碳管的制备及生长机理方面的新进展。     

充金属对Fe3Al合金焊接性的影响

采用氩弧焊方法，并添加不同成分填充金属，对Ｆｅ３Ａｌ基合金进行焊接性试验。结果发现，当采用１Ｃｒ１８Ｎｉ９Ｔｉ不锈钢焊丝焊接后，焊缝发生自开裂现象。金相和ＳＥＭ观察发现，焊缝中心低熔点相偏析严重，焊缝一次柱状晶发达，并且晶间发生开裂；若选用与母材同成分的焊丝，并采取相同的焊接工艺，则焊接性良好，而且焊缝具有相当的强度。     

新型纳米材料——纳米碳管

纳米碳管是一种新型的纳米材料，其独特的分子结构和性能引起了人们的广泛关注。本文从材料科学的角度简要介绍了纳米碳管的发现、发展、制备方法、分子结构以及在材料领域的广泛应用和重大意义。     

填充金属对Fe_3Al合金焊接性的影响

采用氩弧焊方法，并添加不同成分填充金属，对Ｆｅ３Ａｌ基合金进行焊接性试验。结果发现，当采用１Ｃｒ１８Ｎｉ９Ｔｉ不锈钢焊丝焊接后，焊缝发生自开裂现象。金相和ＳＥＭ观察发现，焊缝中心低熔点相偏析严重，焊缝一次柱状晶发达，并且晶间发生开裂；若选用与母材同成分的焊丝，并采取相同的焊接工艺，则焊接性良好，而且焊缝具有相当的强度。     

碳纳米管的球磨处理及其对储氢性能的影响

采用电子显微镜分析技术研究了碳纳米管经过不同时间和不同方式机械球磨处理后其微观组织和结构的变化，并探讨了球磨对碳纳米管储氢性能的影响。研究结果表明，机械球磨可以截断碳管，碳管长度从原来的微米级降到几十到几百纳米；同时碳管端口打开，缺陷增多，表面积增大。在球磨的碳管中加入纳米级MgO，可使球磨效果更显著。球磨2h处理的碳纳米管的储氢量是未球磨碳纳米管储氢量的2倍以上，达到0.44wt％。而加入MgO球磨1h后，其储氢量达到0．81wt％。     

碳纳米管的特性及其高性能的复合材料

碳纳米管具有超强的力学性能、极高的纵横比和独特的导电特性,是制备复合材料的理想形式。评述了目前碳纳米管复合材料的制备及其应用研究的动态。用化学镀方法制备的镍基碳纳米管复合镀层比传统的复合镀层具有更高的耐磨性能,结构为非晶态。讨论了复合镀制备金属基碳纳米管复合镀层的优越性及应用。用原位聚合法合成了导电聚苯胺-碳纳米管的复合材料,可以作为电池和电化学超级电容器的电极材料。      

Surface analysis, hydrogen adsorption and electrochemical performance of alkali-reduce treated hydrogen storage alloy

The hydrogen storage alloy powders (M1Ni4.0Co0.6Al0.4, M1 = rich-La mischmetal) were treated in a hot 6 mol/L KOH 0.02 mol/L KBH4 solution, the surface compositions and chemical states of the treated and untreated alloys were analyzed by XPS and EDX, the hydrogen adsorption on the surface of these alloys was evaluated by thermal desorption spectroscopy (TDS), the effects of the surface treatment on the electrochemical performances of the alloy electrodes were investigated. The results show that the hydrogen adsorption is greatly strengthened by the surface modification, and hence leads to marked improvement in the electrocatalytic activity, the treated alloy exhibits higher exchange current density and lower apparent activation energy for the hydrogen electrode reaction than the untreated alloy.