共查询到20条相似文献,搜索用时 62 毫秒
1.
3.
4.
溶胶-凝胶法制备纳米复合材料的研究进展 总被引:1,自引:0,他引:1
溶胶-凝胶法用于制备纳米粒子复合材料,因组分、制备途径和结构等可优化设计,故产物性能优异。本文介绍了溶胶-凝胶法制备的纳米粒子复合材料在光学、电子、磁学、生物、催化等领域的应用和最新研究进展。 相似文献
5.
6.
7.
典型的商业化太阳能电池组件封装结构由光伏玻璃、胶膜、电池片、背膜等部分组成,由于光伏封装玻璃与空气之间存在界面,会带来约4%的太阳光反射,这部分太阳光无法参与到光电转换过程中,造成了一定的光损耗。减反射膜可以有效地抑制由于界面存在折射率差而导致的光反射损耗,因此,在光伏组件中普遍需要在光伏玻璃表面镀减反射膜,这具有重要的现实意义和巨大的经济价值。然而,由于太阳光的宽谱特性,光伏组件面临着严苛的户外环境使用要求,这需要光伏玻璃减反射膜不仅具有较好的减反增透特性,还需在复杂环境下保持稳定,并且符合光伏产业大面积、低成本、均匀成膜的技术要求。事实上,实现兼具以上特性的减反射膜材料制备和镀膜是极具挑战的。与玻璃衬底折射率匹配的减反射膜需要具有极低的折射率(低于自然界中天然材料的折射率),为了获得这种超低折射率需要在材料中引入一定比例的孔隙结构,而这与所要求的严苛环境下材料的稳定性存在矛盾。因此,光伏玻璃减反射膜研究除追求优异的光学特性外,维持其在复杂气候条件下的稳定性也至关重要,减反射膜耐候性、机械强度以及多功能特性(如自清洁、防尘抗污和防潮等)增强方面的探索都成为主要研究课题。在光学特性方面,利用仿生折射率渐变结构提升减反射膜的宽光谱、广角减反特性研究已取得了一系列进展。而在光伏产业中,基于光学特性、稳定性和制造成本的考虑普遍采用溶胶-凝胶二氧化硅单层减反体系,相比于传统的纳米实心二氧化硅颗粒制备的多孔二氧化硅减反射膜,新型介孔二氧化硅和具有封闭孔隙结构的空心二氧化硅减反射膜体现出更好的耐候性和机械强度,同时维持了所需的孔隙率,保持了较好的减反增透特性。此外,为了应对在不同气候环境下的长期应用需求,研究者们进行了一些二氧化硅减反射膜自清洁和防尘抗污等多功能改性方面的探索,但目前在实现同时具有优异的光学特性、较高的力学性能和长效的耐候性的多功能减反射膜方面仍存在较大挑战。本文归纳了光伏玻璃减反射膜的研究进展,从减反射膜的基本概念、原理出发,介绍了针对光伏玻璃减反射膜的特定评价方法,并围绕当前光伏产业中普遍采用的溶胶-凝胶二氧化硅单层减反射膜制备技术进一步对具有三类不同孔隙结构的二氧化硅减反射膜体系进行了介绍,分析了光伏玻璃减反射膜所面临的问题并对其发展趋势进行了展望,以期为制备减反增透特性更优异、在极端环境下更稳定和具有更丰富表面功能特性的新型光伏玻璃减反射膜提供参考。 相似文献
8.
9.
10.
11.
A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils. 相似文献
12.
The end of over unit products of more than Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits beer wine yellow wine fruit syrup wine others cover over % of the national top-branded liquor products.…… 《中国标准化(英文版)》2008,25(1):30
The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.…… 相似文献
13.
Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster. 相似文献
14.
N.A. Odintsova N.V. Ageenko K.V. Kiselev N.M. Sanina E.Y. Kostetsky 《International Journal of Refrigeration》2006,29(3):387
We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes. 相似文献
15.
David R. Smith F. R. Fickett 《Journal of research of the National Institute of Standards and Technology》1995,100(2):119-171
Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability. 相似文献
16.
Fco. Javier Franco Pérez Marc Gener Moret 《Materials and Manufacturing Processes》2017,32(7-8):876-884
ABSTRACTThe production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials. 相似文献
17.
As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion. 相似文献
18.
Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting. 相似文献
19.
TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure. 相似文献
20.
R. Owsiński S. Kamiński M. Szymaniec A. Niesłony T. Łagoda 《Materialwissenschaft und Werkstofftechnik》2015,46(10):1059-1067
The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase. 相似文献