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11.
Silver metal has been synthesized in form of a finely divided loose nanopowder, 10–30 nm particle sizes, using a simple polyol process. In hot water, polymer molecules of polyvinyl alcohol (PVA) induce Ag+ → Ag reaction as a weak reducer (suitable to control the final particle size), forming a nanofluid of Ag nanoparticles in situ dispersing in part of PVA molecules. Ag nanoparticles do not aggregate much when casting a viscous Ag–PVA nanofluid (hot) onto a substrate in thin laminates or films. Freestanding Ag–PVA films could be obtained of 1–5 mm thickness after drying at room temperature. Dried sample can be easily peeled from a silicate glass substrate. As small as 5–10 mm Ag–PVA pieces were heated in air in order to recollect Ag nanoparticles by burning off the polymer. At 300–400 °C, Ag–PVA disintegrates and encounters combustion in air, resulting in a pure Ag-powder. As analyzed by X-ray diffraction, a single crystalline phase of an Fm3m cubic crystal structure formed. Lattice parameter a = 0.4071 nm and density ρ = 10.61 g/cm3 compare well the bulk values a = 0.4086 nm and ρ = 10.50 g/cm3. 相似文献
12.
V. F. Ivanov A. A. Nekrasov K. V. Tcheberiako A. V. Vannikov A. S. Posed'ko S. I. Lishik Yu. V. Trofimov 《Journal of the Society for Information Display》2003,11(1):11-14
Abstract— An all solid‐state photoelectrochromic element (PECE) was developed on the basis of electrochromic layers of WO3 and polyaniline with a layer of polymer electrolyte placed on a base of polyamidosulfoacid, in which a thin‐film CdSxSe1?x photoresistor was used as an electronic key. The dependence of the sensitometric characteristics of the PECE on the applied voltage was studied. 相似文献
13.
Chihiro J. Uchibori Y. Ohtani T. Oku Naoki Ono Masanori Murakami 《Journal of Electronic Materials》1997,26(4):410-414
Significant reduction of the contact resistance of In0.7Ga0.3As/Ni/W contacts (which were previously developed by sputtering in our laboratory) was achieved by depositing a W2N barrier layer between the Ni layer and W layer. The In0.7Ga0.3 As/Ni/W2N/W contact prepared by the radio-frequency sputtering technique showed the lowest contact resistance of 0.2 Ωmm after annealing
at 550°C for 10 s. This contact also provided a smooth surface, good reproducibility, and excellent thermal stability at 400°C.
The polycrystalline W2N layer was found to suppress the In diffusion to the contact surface, leading to improvement of the surface morphology and
an increase in the total area of the InxGa−As between metal and the GaAs substrate. These improvements are believed to reduce the contact resistance. 相似文献
14.
The search for dielectric materials with a high dielectric constant and ′r = ƒ(T) curves with a flat profile fitting the X7R specification is still ongoing. Promising results were obtained by mixing compounds with closely related structures, such as the tetragonal tungsten bronze (TTB) niobate K2Sr4Nb10O30 and the perovskite Pb(Mg1/3Nb2/3)O3 (PMN). The present study, based on three methods of synthesis, explores the origin of the spreading out of the dielectric curves ′r = ƒ(T). For the composition 10x K0.2Sr0.4NbO3 (KSN) + (1 − x)Pb(Mg1/3Nb2/3)O3 (PMN) with x = 0.3–0.6, the three synthesis methods provided similar characteristics and for the highest perovskite ratio (x = 0.3), the ′r = ƒ(T) curve exhibits a flat profile. When lithium is used as a sintering agent, ′r = ƒ(T) curves present a linear dependency with the temperature. These materials are also characterized by a structural and a microstructural inhomogeneity. Two phases TTB and perovskite type, different from KSN and PMN, are present after calcination and sintering, but not evenly distributed. The PbO loss during sintering also contributes to the evolution of the properties of the material. 相似文献
15.
16.
简要回顾了我国钨矿业悠久的历史、资源的优势、技术的进步和卓越的贡献 ;20世纪80年代中期以后 ,逐步陷入困境 ,举步维艰的主要表现 ;以及在解决“四矿”(矿业、矿山、矿工、矿城)问题中的艰苦经历。指出应在“四矿”问题讨论中做更多、更深的对策思考 ,并对钨业的“四矿”问题加以重点研究。 相似文献
17.
笔者较为详细地阐述了利用含钨废催化剂生产钨酸的工艺流程、各工序反应原理及其操作工艺实践、产品质量情况、原辅材料单耗等。实践证明 ,该工艺实用性强 ,具有显著的经济效益、社会和环保效益。 相似文献
18.
研制了一种新型微合金非调质钢。通过合理设计合金成分,改善熔炼脱氧过程,控制钢中氧化物的组成、分布、形状和尺寸,在研制钢中形成微细的氧化物夹杂作为晶内铁素体最有利的析出位置。通过晶内铁素体的析出细化了晶粒,提高了钢的强度与韧性。将研制的新型微合金非调质钢用于拖拉机的牵引插销是可行且有效的。 相似文献
19.
对双层翼缘板焊接工型钢吊车梁的某些受力特征、吊车梁的支座节点连接构造设计等进行了较详尽的分析,提出了满足冶金工业厂房大跨度、大吨位吊车梁系统受力和工艺要求的方法. 相似文献
20.
利用含钨废催化剂生产钨酸工艺实践 总被引:10,自引:1,他引:9
较为详细地阐述了利用含钨废催化剂生产钨酸的工艺流程、各工序反应原理及其操作实践、产品质量情况、原辅材料单耗等。实践证明 ,本工艺具有显著的经济效益和社会效益、环保效益 相似文献