化学镀Ni-P-Cr2O3和Ni-P-SiO2复合镀层的研究

本文对化学镀镍及化学镀镍磷基质中SiO2与Cr2O3的共沉积进行了研究.微粒在不断生长的膜层中共沉积引起了新的化学复合镀层的出现,这些复合镀层许多都具有优异的耐磨及耐蚀性能.通过选取镀层合金/复合微粒/金属基体的组分可改进镀层,获得所需的性能,以满足特别的需求.在对这些复合镀层的应用需求正在迫近与增长的同时,其市场正在迅速扩张.本文开发出了一种合适的复合化学镀镍液,并通过维氏硬度法对化学复合镀镍层进行了表征.采用动电位极化及交流阻抗法测定了镀层的Taber耐磨性能及耐蚀性能.采用SEM及XRD对复合镀层的表面形貌进行了分析.     

Gradient minimax techniques for system modelling

Some recently proposed gradient methods for minimax or near minimax approximation are applied to producing optimal second-order and third-order models of a high-order system. The Fletcher-Powell method, a more recent method by Fletcher and o. method by Jacobson and Oksman are employed with least pth approximation, using large values of p, as proposed by Bandler and Charalambous and critically compared with the grazer search technique of minimax approximation by Bandler et al. The solutions obtained are shown to satisfy the necessary conditions for a minimax optimum.     

Features-based castability evaluation

A features-driven knowledge-based approach to the quantitative assessment of castings for ease of manufacture is presented. Geometric features such as undercuts, holes, sharp corners and hot spots are recognized from a solid model of the casting and analysed by a number of dimensionless criteria functions. The criteria have been developed through a detailed study of design heuristics used by practising engineers and are written as functions of geometric attributes of component and tool features. This is useful for identifying problem features in a casting at an early stage and for objective comparison of two or more design solutions for manufacturability. The proposed approach lends itself to computer implementation for automating the design of castings in a concurrent engineering environment.     

Semi-Markov performance model of an extended token bus protocol†

In this paper we present the semi-Markov performance model of a bus protocol (IMAP—Improved token bus Multi-Access Protocol) suitable for embedded networks. IMAP is an improvement over the token bus scheme and is proposed in Sood et al. (1986). The semi-Markov model is developed by considering normal and interrupt modes of operation of IMAP. Performance of IMAP has been compared to token-bus scheme.     

Structure-Digestibility Relationship of Legume 7S Proteins

Structure-digestibility relationship was investigated in in vitro model systems for phaseolin and vicilin, the major 7S storage proteins of dry bean and green peas, respectively. Native phaseolin was more resistant to trypsinolysis than vicilin, while heating caused a reversal of proteolysis rates. Conformational studies using far-uv and near-uv CD spcctroscopy suggested the native conformatin of vicilin to be far more flexible to thermal treatment and SDS-induced environmental changes; however, neither the thermal treatment nor the anionic detergent caused a complete randomization of structure in either proteins studied. Ironically, the flexible native conformation of vicilin seemed to induce greater undesirable changes upon heating so as to confer resistance to proteolysis. The possible role of secondary and quarternary structures of these two proteins is descussed in relation to their digestibility.     

Recovery of Proteins from Raw Sweet Whey Using a Solid State Sulfitolysis

A simple, efficient method to recover functional proteins from cheese whey was developed. It involves partial sulfitolysis of disulfide bonds in whey proteins using sodium sulfite and solid state copper carbonate catalyst. About 25 to 40% of the initial disulfide bonds were modified within 15 to 30 min at pH 7.0. When treated whey was adjusted to acidic pH, about 70 to 80% of the whey proteins precipitated below pH 5.0. The protein precipitate contained some copper as protein-copper complex. However, extraction of the precipitate with EDTA at pH 4.5 completely removed the copper. The uncomplexed protein showed a U-shaped pH-solubility profile with 100% solubility below pH 3.0 and above 6.0. About 90% of the proteins precipitated in the pH range 4.0 to 5.0. The method could be used on an industrial scale to recover highly functional and nutritional whey protein for use in a variety of products.     

发光化学镍复合镀层(英文)

在90℃下,采用含有25 g/L硫酸镍,20 g/L次磷酸钠、35 g/L柠檬酸钠、0～6 g/t,卤磷酸钙和15 g/t.硫酸铵的镀液(pH 5.5),制备了基于卤磷酸钙的发光化学镍复合镀层.研究了镀液pH对复合镀层的沉积速率及卤磷酸钙含量的影响.采用硬度测量、磨损测试、腐蚀试验、紫外光谱,扫描电镜和X射线衍射对复合镀层进行了表征.在最佳卤磷酸钙质量浓度(4 g/L)下所得的复合镀层含77.59%(质量分数)镍、7.58%(质量分数)磷和14.83%(质量分数)卤磷酸钙.由于卤磷酸钙是硬质粒子,随着其嵌入量的增多,复合镀层的硬度增大.在存在卤磷酸钙的条件下,化学镍复合镀层的耐磨和耐蚀性能均显著提高.     

EFFECT OF SOLVENT EXTRACTION ON REMOVAL OF NUTTY FLAVOR AND FUNCTIONAL PROPERTIES OF GROUNDNUT FLOUR

Hexane extracted groundnut flour was re-extracted with absolute ethanol, 95% isopropanol, hexane:ethanol and hexane:isopropanol azeotropes for different time intervals. Sensory evaluation studies indicated that 6 h extraction with ethanol or isopropanol and 24 h extraction with hexane; ethanol azeotrope removed nearly 80–90% of nutty flavor. Some significant changes were observed in water absorption capacity, emulsification capacity and foaming properties of secondary solvent extracted meals. No significant changes were observed in fat absorption capacity, protein solubility and amino acid composition of secondary extracted samples. Gel electrophoresis did not reveal any marked changes in the protein composition of the reextracted meals.