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51.
Olaf Ueberschär Carolin Wagner Tim Stangner Christof Gutsche Friedrich Kremer 《Polymer》2011,52(8):1829-4032
Optical tweezers accomplished with fast position detection enable one to carry out Brownian motion analysis of single DNA-grafted (grafting density: ∼1000 molecules per particle, molecular weight: 4000 bp) colloids in media of varying NaCl concentration. By that the effective hydrodynamic radius of the colloid under study is determined and found to be strongly dependent on the conformation of the grafted DNA chains. Our results compare well both with recent measurements of the pair interaction potential between DNA-grafted colloids (Kegler et al. Phys Rev Lett 2008; 100:118302) and with microfluidic studies (Gutsche et al. Microfluid Nanofluid 2006; 2:381-386). The observed scaling of the brush height with the ion concentration is in full accord with the theoretical predictions by Pincus, Zhulina, Birshtein and Borisov. 相似文献
52.
电刷使用寿命的评估方法 总被引:1,自引:0,他引:1
提出了采用辛普森三点式进行电刷使用寿命评估的方法。经初步试验,用该方法不但能快速且较准确地评估电刷的使用寿命,还可分析评价电刷的工作状况。 相似文献
53.
周细枝 《湖北工业大学学报》2005,20(5):98-100
应用电刷镀技术在45钢表面制备含有微米SiO2的镍基复合镀层,研究了复合镀层表面形貌,测试了镀层的显微硬度和摩擦磨损性能,分析了微米陶瓷颗粒沉积量对镀层摩擦磨损性能的影响.实验结果表明,微米陶瓷颗粒复合镀层较快速镍镀层具有更高的显微硬度和良好的耐磨性. 相似文献
54.
Droplet: A virtual brush model to simulate Chinese calligraphy and painting 总被引:1,自引:0,他引:1
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Xiao-FengMi MinTang Jin-XiangDong 《计算机科学技术学报》2004,19(3):0-0
This paper proposes a virtual brush model based on droplet operation to simulate Chinese calligraphy and traditional Chinese painting in real time. Two ways of applying droplet model to virtual calligraphy and painting are discussed in detail The second droplet model is more elaborated and can produce more vivid results while being slightly more time-consuming. The novel feature of the proposed droplet virtual brush model successfully enables the simulation painting system to overcome the poor expressional ability of virtual brush based on particle system and avoids the complex evaluation of physical brush with solid model. The model, derived from the actual calligraphy and painting experience, due to the simplicity of the droplet operation and its powerful expressive ability, considerably improves the performance of the simulation system and maintains painting effect comparable with real brush by supporting special Chinese brush effect such as dry brush, feng and stroke diffusion. 相似文献
55.
结合电刷镀纳米复合镀层的沉积机理,对目前所进行的纳米复合镀层性能的研究状况进行了阐述,并指出了纳米复合电刷镀技术在模具修复中广阔的发展前景. 相似文献
56.
针对柳林电力有限责任公司1号机碳刷电流分布严重不平衡,甚至烧伤滑环的案例,通过测试数据分析,提出逐步更换上海摩根NCC634碳刷、精密安装刷架等整改措施,实施后效果良好。 相似文献
57.
Eylem Turan 《Thin solid films》2010,518(21):5950-310
Thermoresponsive poly(N-isopropylacrylamide) [poly(NIPAM)] brush on silicon wafer surface was prepared by combining the self-assembled monolayer of initiator and atom transfer radical polymerization (ATRP). The resulting polymer brush was characterized by in situ reflectance Fourier transform infrared spectroscopy, atomic force microscopy and ellipsometry techniques. Gel permeation chromatography determination of the number-average molecular weight and polydispersity index of the brush detached from the silicon wafer surface suggested that the surface-initiated ATRP method can provide relatively homogeneous polymer brush. Contact angle measurements exhibited a two-stage increase upon heating over the board temperature range 25-45 °C, which is in contrast to the fact that free poly(NIPAM) homopolymer in aqueous solution exhibits a phase transition at ca. 34 °C within a narrow temperature range. The first de-wetting transition takes place at 27 °C, which can be tentatively attributed to the n-cluster induced collapse of the inner region of poly(NIPAM) brush close to the silicon surface; the second de-wetting transition occurs at 38 °C, which can be attributed to the outer region of poly(NIPAM) brush, possessing much lower chain density compared to that of the inner part. 相似文献
58.
59.
The growth of the powder coating business is affected by the toxicological effects of the raw materials used in the coating formulation and the saturation of the present market for powder coatings, being limited to general metal applications only. This has a strong influence on the long-term research programmes at both raw materials suppliers and powder paint producers. In the last decade of the 20th century, we witness appearance of several new types of toxicologically-safe powder coating systems on the commercial scale. At the same time, there is strong evidence of efforts to penetrate new market fields where powder coatings are not typically used. This includes the markets for automotive clear top coatings, can and coil coatings, coatings for industrial wood, plastics and paper. The new developments in the chemistry of powder coatings are followed by changes and improvements in the production technology for powder coatings as well as developments of new application techniques. This paper summarises the research work on chemistry, production and application technology of powder coatings and tries to extrapolate the tendencies in the years to come in order to predict the achievements and the impacts on the paint industry. 相似文献
60.
A series of well-defined brush-type amphiphilic polystyrene-g-poly(2-(dimethylamino) ethyl methacrylate)) (PS-g-PDMAEMA) copolymers were successfully synthesized via atom transfer radical polymerization (ATRP), using chloromethylated polystyrene (CMPS) as the macroinitiator. The self-assembly behavior of the resulting brush-type copolymers in deionized water and deionized water/acetone (v/v=2/3) mixture was studied by high performance particle sizer (HPPS). The results showed that the Z-average size of the micelles in deionized water increased with the increase of molecular weight of PDMAEMA, and the corresponding size was larger than that in mixed solvent of deionized water and acetone (v/v=2/3). The morphologies of the micelles self-assembled from PS-g-PDMAEMA in selective solvents were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). When the micelles were prepared in water/acetone (v/v=2/3) mixture and cast them on a glass slide at different temperatures (from 50 up to 200 °C), the transformation of the morphologies of aggregates, from needle-like solid to microcubic particles, was observed using SEM. 相似文献