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81.
82.
As part of a study of the possible application of polymerisable Langmuir-Blodgett (LB) films as ultra-fine-line e-beam resists, an investigation of the variation of film structure of 22-tricosenoic acid with differing deposition conditions has been made. Unexpected effects with significant implications for deposition speed and resist sensitivity have been observed, and the new techniques for film characterisation developed during the investigation have resulted in a revised model of deposition explaining the observed independence of the disorder causing optical scattering and the macroscopic features observed by polarised microscopy. 相似文献
83.
金刚石磨具已广泛用于宝石加工业。对电镀法制造金刚石磨具进行了试验研究,该工艺可分为电镀前的预处理、金刚石磨具的电镀工艺,对影响镀层质量的因素进行了分析。 相似文献
84.
85.
非晶软磁合金的巨磁阻抗效应及应用 总被引:3,自引:2,他引:1
近来在FeCoSiB等Co基非晶体丝带中现了巨磁阻抗效应,由于在一小的直流纵向偏置场下该效应能使丝带两端的交流电压发生大而灵敏的变化,因而在磁记录头和传顺技术中具有巨大的应用科学潜能,受到各国学者的关注,本文简单介绍了巨磁阻抗效应的来源,并综述了近年来非晶体软磁合金材料的的巨磁阻抗效应及应用的研究进展,文章最后说明了尚待深入解决的问题。 相似文献
86.
87.
在对81/2B125金刚石钻头进行有限元计算分析后,找出最大应力点在金刚石钻头冠部切削告处。通过改变各相关尺寸和结构型式,用有限元法模拟试验过程,在给定结构参数和工艺参数情况下获得多组数据。根据专业知识,参考有限元计算获取的各组数据变化特征,选出拟合较好的公式类型,再采用回归分析方法确定待定系数,最后得出工程上实用的金刚石钻头强度验算公式。用这个公式对81/2B461W和121/4B331金刚石钻头进行了强度验算,经改进设计后钻头在现场使用取得了良好的效果。 相似文献
88.
Properties of Edible Films from Total Milk Protein 总被引:5,自引:0,他引:5
The mechanical properties and water vapor permeability of edible films made from various total milk proteins (TMPs) were investigated. Two TMPs obtained from nonfat dry milk (NDM) by removing lactose and three TMPs obtained from a commercial source were studied. Lactose was extracted from NDM by ultrafiltration or suspension in ethanol followed by filtration. TMP concentrate obtained by ultrafiltration (UF) produced films with the lowest water vapor permeability (WVP) and the highest tensile strength at break. Commercial TMP concentrates produced films more ductile than those from the UF-TMP or retentate from ethanol extraction. Further research is needed to improve mechanical properties of UF-TMP films without increasing the WVP. 相似文献
89.
This study describes the development of multilayer metal-dielectric graded index solar selective coatings in which the metallic volume fraction increases with depth, from top (air–film interface) to bottom (film–substrate interface). The work is based on computer simulation followed by validation through fabrication of the coatings and optical measurements. The influence of the choice of the number of layers present in a graded index composite selective absorber and results obtained for a new destructive interference bilayer (four-layer system) coating, designed using the computer model, were studied. The design and optimization of the composite coating was undertaken using a computer tool developed within this program of research employing Bruggeman and Maxwell–Garnett effective medium formalisms. The design tool enabled all key design parameters, with the exception of particle size and orientation, to be varied systematically to permit the sensitivity of the optical properties of the selective absorber coating to be studied.The model was validated with a supporting program of experimental research in which many different selective absorbers were prepared by co-sputtering of metal and dielectric materials.Although the best compositional gradation can be achieved by increasing the number of layers, the variation in optical performance beyond a certain number of layers is minimal. The destructive interference produced between adjacent layers contributes to the absorptance. The effect of the number of layers (single, four and 10) has been calculated for various materials such as nickel, vanadium, tungsten, cobalt and chromium based coatings. Solar absorptance of 0.98 and 0.96 was achieved by simulation and experimental findings with less than 0.07 thermal emittance at 300 K for 200 nm thick, 4-PGSAC (four-layer system) of V : Al2O3 composites. Other designs showed lower optical performance for all the material combinations regardless of their individual optical properties. Use of such thin film coating on the absorbers of solar thermal appliances can reduce thermal losses significantly, which could be of importance to the relevant industry. 相似文献
90.
Free radical emulsion polymerization of methyl methacrylate (MMA) and 2‐ethylhexyl acrylate (EHA) results in the synthesis of pressure‐sensitive adhesives (PSAs) with good tack properties. Management of both the copolymer composition and the polymerization process allows one to control the behavior of the PSA. Semicontinuous (SC) processes create polymer particles whose instantaneous composition is close to that of the feed particle The SC Mixture process (continuous feeding with comonomer blends) affords nearly homogeneous latex particles and PSA films. The SC Gradient process (separate feedings at inversely varying rates) affords heterogeneous particles and films. The Batch process leads to somewhat heterogeneous films, but the hard (MMA‐rich) microdomains are made compatible with their soft (EHA‐rich) matrix because of the assumed formation of tapered‐type copolymers. Tack measurements indicate the importance of the particle and film structures. Too much hardness or softness leads to unacceptable lacks of adhesion and cohesion, respectively. Homogeneous structures prove adequate, but their tack properties collapse with rising temperature. Heterogeneous structures, with extensive phase segregation, prove unsatisfactory because they lack adhesion and cohesion. Finally, the association of well‐balanced composition and compatible heterogeneity is the criterion for suitable PSA behavior. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2749–2756, 2003 相似文献