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非晶硅太阳能电池的新进展 总被引:1,自引:0,他引:1
对非晶硅材料的物理性能及工艺优势进行了阐述,其中介绍了一种新型的刻划成图工艺,即等离子CVM,简单回顾了非晶硅太阳池的历史发展,分析了非晶硅太阳电池当前所存在的问题,提出了其发展的方向,其中,主要论述了叠层非晶硅太阳电池,并介绍了几种新型的非晶硅电池,最后,概括了非晶硅太阳电池的应用现状及前景。 相似文献
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本叙述了Internet来自外部,内部,硬件,软件方面的十种安全威胁和攻击,给出了防火墙的限制,隔离,筛选,过滤和屏蔽作用,介绍了防火墙的六种基本结构类型,论滤了过滤路由器,双宿主主机,主机过滤,过滤子网和吊带式五种安全结构,分析了传统防火墙的七种不足,给出了目前防火墙混合应用包过滤技术,代理服务技术和其他一些技术的发展趋势。 相似文献
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本文简述了无线寻呼机制造技术的最新发展,详细介绍了寻呼机在小型化,增加信息存储,提高抗干扰能力,增加新功能方面采用的新技术,新方法,强调了模糊技术,纠错技术对提高寻呼机抗干扰能力的作用,最后,展望了寻呼机制造技术的发展趋势。 相似文献
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重庆市“教学与集邮”活动已走过10年的历程。10年来,存重庆邮政、邮协及各级教委的支持下,重庆市各中小学对“教学与集邮”展开了广泛深入的研究,组织了集邮活动,举办了集邮讲座,推出了一批“教学与集邮”校本教材,取得了累累硕槊。集邮进校园、进课堂,使集邮活动在校园扎根,大大丰富了校园文化内容,引发了广大青少年对集邮这项健康、文明活动的兴趣,拓宽了学生的综合宴践能力,陶冶了学生的高尚情操,提高了学生思想素质和文化艺术素养,培育了集邮队伍的生力军。 相似文献
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介绍了安徽电视台开放式演播室的整体布局,逐一分析了电源,灯光,视频,音频,通话,指示,时钟和传输系统,其中重点介绍了视频和音频系统。 相似文献
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频道多了,节目也要跟上吴为忠文年岁渐长,早已过了不惑之年,到了这样的年龄,晚上如果没有公务缠身就懒得外出,看电视似乎成了我业余生活的一个主要内容。但是,电视看得多了,总忍不住要说三道四,这也许是一种职业病。我的住处已经装上了闭路电视,又与有线电视台联... 相似文献
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移动通信网络优化服务由于借助了设备厂商和专业第三方优化服务公司的技术优势,很好地提升了现有网络运行的质量,弥补了网络运营商技术人员的缺口,培养了运行维护人员的专业技能,积极发挥了现有网络资源的利用率,有效地降低了网络的维护成本,提高了客户的满意度和运营效益, 相似文献
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Navpreet Kaur Dario Zappa Valentin-Adrian Maraloiu Elisabetta Comini 《Advanced functional materials》2021,31(38):2104416
Establishing a platform comprising different nanostructured oxides is an emerging idea to develop highly sensitive and selective sensing devices. Herein, novel 3D-heterostructures (p–p–n) consisting of 1D nanowires of NiO and WO3 along with their intermediate reactive product, i.e., NiWO4 seed, are produced by a two-steps vapor phase growth method. In-depth morphological and structural investigations describing the growth mechanism of these heterostructures are presented. Finally, the p–p–n heterostructures are integrated into conductometric sensing devices and their performances are investigated toward different gases. It is observed that by modulating the charge-carrier transport with temperature, the heterostructure sensors exhibit selective behavior toward different gas analytes. Indeed, at 300 °C, the heterostructure sensors show relatively selective behavior toward NO2, while at 400 °C, high selectivity toward VOCs is observed. The improvement in sensing performances is mainly based on charge carrier transport through the two interfaces (one at WO3/NiWO4 (n–p) and the other at NiWO4/NiO (p–p)) and the modulation of charge carriers in the electron depletion layer of WO3 and hole accumulation layer of NiO and NiWO4. The remarkable performance of these complex heterostructures with low ppb-level detection limits makes them excellent candidates for chemical/ gas sensing applications in e-noses. 相似文献
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气密封装工艺技术是混合电路制造的关键技术。在可靠性要求较高的场合,对混合电路产品提出了水汽含量、漏气率和粒子碰撞噪声检测(PIND)合格率的指标要求。封装内部的多余物对电子器件的可靠性带来严重影响。主要从盒体的表面镀层方面进行讨论,分析了不同的金属化结构和不同的镀层厚度对气密封装的影响。实验表明,当封装使用的压力较大时,化学镀镍外壳的镀层容易出现裂纹,造成外壳锈蚀。外壳使用化学镀镍、电镀金结构时,其PIND不合格率较高。当镀层厚度超标时,不仅PIND不合格率较高,也会出现漏气问题。 相似文献
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随着现代电子技术的不断发展,电路板中将有越来越多的镀镍金表面工艺,来满足开关、触点及耐摩擦等方面的要求。图形的分布不均给电路板镀镍金的表面处理带来了诸如金厚度、金表观等难以克服的缺陷。从电镀的原理方面入手,分析造成这些缺陷的原因,并给出相应的解决办法,为以后选择镀镍金为表面处理方式的产品的加工提供一种新的思路与方法。 相似文献
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碳酸镍沉淀过程的研究以及介孔氧化镍的制备 总被引:1,自引:1,他引:0
Nickel carbonate and nickel oxide are important inorganic fine chemicals, widely used in chemical, metallurgical, electronic and energy sources industries. The research was beginning with studying the effects of anions on precipitation process of nickel carbonate. Activity coefficient shows the effect size of the microcosmic effects between ions and solvent. Meissner's semi empirical model was applied to calculate the average activity coefficients of nickel carbonate in different electrolyte solutions at different conditions. And the conditional solubility of nickel carbonate was also calculated. The calculated results show that activity coefficients of NiCO3 in sodium sulphate solutions are less than that in sodium chloride solutions, and the solubilities in sodium sulphate solutions are larger. To improve the confidence of the calculations, Bromley's and Pitzer's models were also applied to calculate activity coefficients. The calculation results of Bromley's and Pitzer's models are very close to Meissner's results. And then experiments were carried out to measure the surface tensions, and contact angles of solutions on NiCO3 surface. According to the experiment results, the solid-liquid interface tension between NiCO3 and sodium sulphate solution is larger than that between NiCO3 and sodium chloride solution. And the tiny crystal NiCO3 has larger solubility in sodium sulphate solutions, which indicates that crystallization of NiCO3 in sodium sulphate solution is more difficult than in sodium chloride solution. The influence of SO 42- and Cl- on precipitation and crystallization process of NiCO3 was also studied based on crystal dynamics. The supersaturations at different initial concentration of reaction system were compared. Diffusion coefficients of ions were described by Glasstone's model. The diffusion coefficients of Ni2+ and CO 32- in chloride solutions are larger than those in sulphate solutions. In sulphate solutions, the diffusion coefficients and supersaturation are both less, therefore nucleation and growth rates are more slowly. Furthermore, the experiments of crystallization dynamics show that the reaction of nickel carbonate precipitation is a first order reaction while the reaction rate constant is about 0.02 min-1. Based on the theoretical analysis above, technology process of nickel carbonate precipitation was studied subsequently. The effects of nickel salt, feeding mode, controlling pH, reaction temperature and aging condition on purity, particle size, appearance of product and recovery ratio of nickel were investigated. Then using industrial nickel electrolyte solution and sodium carbonate as the raw materials, nickel carbonate product with nickel content of about 51%,average particle size of 17 μm was prepared at optimal conditions, and the recovery ratio of nickel is around 99.5%. Nickel carbonate with high purity was obtained via an innovative impurity removal process, called wash-dry-rewash-redry process. The sodium and chlorine qualitative contents of the nickel carbonate purified by the innovative method are both less than 0.01% and the sulphate content is no more than 0.1%. The mechanism of sodium and chlorine adsorption onto nickel carbonate's surface was discussed, using Stern's model of electric double layer. Moreover computational simulation technology was applied to investigate on how anions affect the crystallization of NiCO3 at atom scale. The lattice structure was relaxed before establishing crystal surfaces. The computational unit cell parameters are very close to the experimental data. Five main surfaces were studied, i.e. the (104), (100), (110), (001) and (101) surfaces. SO 42- substitutes the CO 32- on the outmost layer. Cl- adsorbs onto the surfaces and has relative weaker interaction with the surfaces. Compared with only hydrated surfaces, the growth rates of defected hydrated surfaces significantly decrease, especially for SO 24- defected ones. The (104) surface is the most stable surface and is mainly expressed in the equilibrium morphology of the resulting crystal. Finally, based on the study of nickel carbonate synthesis, nickel oxide with mesoporous structure was prepared by adding template into the nickel source and calcination. The effects of types of surfactant, dosage of surfactant, calcination temperature and calcination time on pore structure and specific surface area of nickel oxide were investigated. The results show that the surface area of the nickel oxide prepared by sodium dodecyl sulphate (SDS, anion surfactant) is much larger than those of which prepared by CTAB and octadecylamine. It is suggested that the inorganic species, basic nickel carbonate, is interacted with the template, SDS, by electrostatic attraction force. The precursor hardly has any surfactant residue after calcination. Nickel oxide with high specific surface area (>200 m2· g-1) is synthesized by adding low amount of template at the mole ratio of SDS:Ni less than 0.1:1.0. The nickel oxide has H3 type hysteresis and the pore size distribution mainly ranges from 2 nm to 10 nm. And it has good thermal stability. 相似文献
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介绍了原子吸收分光光度法分析镍硅铜合金中的镍,硅钼蓝光度法测定镍硅铜合金中的硅含量的方法,并对不同的溶样酸、不同空白液、不同分析方法进行了筛选。 相似文献
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以钯作扩散阻挡层——一种多功能线路板表面处理方法 总被引:2,自引:1,他引:1
电子工业不断的小型化,数种不同互联技术于线路板上电子零件连接及电接点被应用范畴不断增加。基于此用途,线路板组装垫位需被一层最后表面处理保护,如这最后表面处理层可用于不同互联技术,可被称为多功能表面层。钯是一个艮好的镍扩散阻挡层,故此层膜能抵受如焊接及键接之严酷老化测试条件。其两大优点为具有良好热超声波键接性及于无铅焊料之非常优艮焊接性。从预镀导线架过往多年经验已知即使很薄贵金属钯层及金层已可有保证可靠的金线键接性。从这一知识,沉镍浸钯浸金层膜系统(ENIPIG)被研发出来。此崭新表面处理ENIPIG三种金属镀液需互相配合才能于线路板工艺上达成理想多功能层膜。因着其薄贵金属层膜,相对于其他表面处理,可节省颇大的成本。 相似文献