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排序方式: 共有1292条查询结果,搜索用时 277 毫秒
1.
Pan.  WS 许艳阳 《半导体情报》1995,32(5):54-64,39
本文研究了在SF6,CBrF3和CHF3与氧相混合的几种氟化气体等离子体中,SiC薄膜反应离子刻蚀(RIE)的深度。通过监测射频等离子体的光发射谱及产生等离子体的直流偏压来研究刻蚀机理,为了更精确地定量分析刻蚀工艺,使用氩光能测定技术使等离子发射强度转换为相应的等离子物质浓度。为获得选择性的SiC-Si刻蚀及SiC薄膜的各向异性图形,对等离子体条件,如气体混合物的构成,压力和功率进行了研究。首次采  相似文献   
2.
In this work, a model of hydrogen production by double chemical looping is introduced. The efficiency benefit obtained was investigated. The chemical looping hydrogen generation unit is connected in series to the downstream of a chemical looping gasification unit as an additional system for 100 MW·h coal gasification, with the function of supplementary combustion to produce hydrogen. Using Aspen Plus software for process simulation, the production of H_2 and N_2 in the series system is higher than that in the independent Chemical looping gasification and Chemical looping hydrogen generation systems, and the production of hydrogen is approximately 25.63% and 12.90% higher, respectively; The study found that when the gasification temperature is 900 °C, steam-carbon ratio is 0.84 and oxygen-carbon ratio is 1.5,the hydrogen production rate of the system was the maximum. At the same time, through heat exchange between logistics, high-pressure steam at 8.010×10~4 kg·h~(-1) and medium-pressure steam at 1.101×10~4 kg·h~(-1) are generated, and utility consumption is reduced by 61.58%, with utility costs decreasing by 48.69%. An economic estimation study found that the production cost of ammonia is 108.66 USD·(t NH_3)~(-1). Finally, cost of equipment is the main factors influencing ammonia production cost were proposed by sensitivity analysis.  相似文献   
3.
Protein design aims to understand the fundamentals of protein structure by creating novel proteins with pre-specified folds. An equally important goal is to understand protein function by creating novel proteins with pre-specified activities. Here we describe the design and characterization of a tetratricopeptide (TPR) protein, which binds to the C-terminal peptide of the eukaryotic chaperone Hsp90. The design emphasizes the importance of both direct, short-range protein-peptide interactions and of long-range electrostatic optimization. We demonstrate that the designed protein binds specifically to the desired peptide and discriminates between it and the similar C-terminal peptide of Hsp70.  相似文献   
4.
针对淮南矿区入浮煤泥细泥含量高,可浮性差的特点,提出采用合适的药剂配比、较稀的入浮浓度、添加分散剂及脱泥浮选等工艺,可以改善和消除细泥对浮选过程的干扰,提高浮选效果。  相似文献   
5.
为了减少药剂用量,采用单因素试验优选法初步确定煤泥水沉降絮凝剂和无机凝聚剂合理的用量范围,在此基础上确定絮凝剂和无机凝聚剂两个因素的具体水平;以煤泥水初始沉降速度和上清液透光率为考察指标,利用正交试验方法对絮凝剂和无机凝聚剂用量配比进行了优化。结果表明,分子量为1 200万的聚丙烯酰胺(PAM)用量为6.8 g/m3,CaCl2用量为350g/m3时,可以取得很好效果,上清液透光率可达97.70%,初始沉降速度达22.32 cm/min。  相似文献   
6.
Distance vector routing protocols have been widely adopted as an efcient routing mechanism in current Internet,and many wireless networks.However,as is well-known,the existing distance vector routing protocols are insecure as it lacks of efective authorization mechanisms and routing updates aggregated from other routers.As a result,the network routing-based attacks become a critical issue which could lead to a more deteriorate performance than other general network attacks.To efciently address this issue,this paper,through analyzing the routing model and its security aspect,and presents a novel approach on guaranteeing the routing security.Based on the model,we present the security mechanism including the message exchange and update message security authentication mechanism.The suggested approach shows that the security mechanism can efectively verify the integrity and validate the freshness of routing update messages received from neighbor nodes.In comparison with exiting mechanisms(SDV,S-RIP etc),the proposed model provides enhanced security without introducing significant network overheads and complexity.  相似文献   
7.
传统防雷系统存在防雷水平不佳,花费过高等问题,为此,设计一种土壤电阻率影响下输电杆塔线路自主防雷保护系统.结合信息中心机房设计系统的硬件部分,详细描述系统硬件的设计原则.由于土壤电阻率影响下输电杆塔线路的杆塔横担接地,采用延续伸长接地体连接各个基杆塔的接地装置,为输电杆塔线路自主防雷提供一条低阻通道,有效预防输电杆塔线路遭受雷击.仿真实验结果表明,所设计系统能够有效防止雷电攻击,同时为后续的研究奠定坚实的基础.  相似文献   
8.
1. IntroductionCu filnls are very pron1isillg for electronic devices because of both high electromigrationresista11ce alld high electrical conductivity['--']. For a sputter-deposited film, base pressure,deposition rate, substrate temperature and energetic…  相似文献   
9.
指针是C语言的精华部分,也是C语言学习的重点和难点,正确而灵活地应用指针是学习C语言中最重要的环节,也是我们掌握C语言的一个标志。该文从指针的概念、运算、初始化以及与数组和函数的关系五个方面对C语言指针进行了分析和探讨。  相似文献   
10.
Yu FT  Yang Z  Pan K 《Applied optics》1994,33(11):2170-2172
A real-time polychromatic target-detection technique that uses a computer-addressable color liquid-crystal- TV-based joint-transform correlator (JTC) is presented. One of the major features of the polychromatic JTC is that the spectra content of the object can be exploited. Since the liquid-crystal-TV panel is computer addressable, the JTC system can be made adaptive, by which the joint-transform power spectrum can be manipulated. Experimental demonstration of the proposed polychromatic JTC is provided, in which we show that the spatial and the spectral content of targets can be detected.  相似文献   
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