零散天然气化工利用研究

根据零散天然气分散而且量较小的特点对其化工利用的途径进行探讨,提出撬装一步生产尿素、撬装生产甲醇和生产合成油等化工利用途径,并对其技术经济性能进行了估算。     

Chemical composition of melia volkensii gurke: An unrealised browse potential for semi-arid agroforestry systems

Results of chemical analyses of some nutritional characteristics of Melia volkensii browse, important for large wild and domestic herbivores in East Africa, are presented. Seeds, fruit pulp, leaves and twigs had high levels of crude protein, crude fat, minerals and fibre. Newly coppiced shoots (leaves and twigs), old shoots, fruit pulp and seed contained 230, 190, 130 and 320 g kg^-1 dry weight crude protein, respectively. The essential amino acid profile compared well with the FAO scoring pattern. Tyrosine was the first limiting amino acid in the coppice leaves and twigs, lysine in the cotyledons, and threonine and lysine in the endosperm. The concentrations of crude fat in the seed, fruit pulp, coppice shoots and old shoots were 480, 100, 80 and 50 g kg^-1, respectively. The fatty acids in the cotyledon and endosperm were mainly palmitic (110 and 109 g kg^-1, respectively), oleic (327 and 252 g kg^-1, respectively) and linoleic (487 and 573 g kg^-1, respectively). The levels of P, Na, K, Ca, Mg and the Ca/P ratio per kg dry weight were on average higher than the optimum recommended for ruminants. These results demonstrate that M volkensii browse, especially coppice leaves and twigs, have a high index for nutrient content, and the planting of this species should be promoted in the semi-arid areas to supplement senescent grasses and cereal crop residues.     

蛋白质功能预测方法研究进展

蛋白质功能预测是后基因组时代生物信息学的研究热点之一。利用计算方法预测蛋白质的功能,可以弥补传统生物实验方法周期长、效率低和成本高等方面不足。首先介绍蛋白质功能预测的研究背景,并从计算角度定义蛋白质功能预测问题;然后,对蛋白质功能预测方法的研究现状进行分析与总结,最后指出已有方法中存在的不足及未来的研究方向。     

激光熔覆制备原位自生增强颗粒复合涂层

采用高能束横流HL-5000型CO2激光器在铸钢表面熔覆了含有碳氮化钛增强粒子的铁基熔覆层。利用X射线衍射(XRD)和能谱EDAX对熔覆层进行了分析, 并采用光学显微硬度计对熔覆层的硬度进行了测试。利用金相显微镜(OM)和扫描电镜(SEM)对激光熔覆层的微观组织进行了研究。结果表明: Ti(C0.3N0.7)可以通过原位反应合成, 新的颗粒状强化相Ti(C0.3N0.7)的形貌特征多呈不规则形状, 弥散分布在熔覆层基体中。熔覆层与母材形成良好的冶金结合, 熔覆层内为方向性强的胞状树枝晶, 晶粒细小。熔覆层的显微硬度HV0.3达到730～850。     

A Cost-Effective Design for MPEG-2 Audio Decoder with Embedded RISC Core

MPEG-2 audio decoding algorithms are involved of several complex coding techniques and therefore difficult to be implemented by an efficient dedicated architecture design. In this paper, we present an effective architecture for the MPEG-2 audio decoder. The MPEG-2 audio algorithms can be roughly divided into two types of operations. The first type is regular but computation-intensive such as filtering, matrixing, degrouping, and transformation operations. The second type is not regular but computation-intensive such as parsing bitstream, setting operation mode and controlling of all system operations. A RISC core with variable instruction length is designed for the decision-making part, and the dedicated hardware such as special divider, and synthesis filterbank is designed for the computation-intensive part. Based on the standard cell design technique, the VLSI chip consists of 27000 gate counts with the chip size of 6.4 × 6.4 mm². The chip can run at maximum 43.5 MHz clock rate, with the power dissipation of 150 mW at 3 V power supply.     

螺旋藻蛋白质浓缩物的制备及其功能特性的研究

本文研究了螺旋藻蛋白质浓缩物制备工艺条件,并对螺旋藻粉及其蛋白质浓缩物蛋白质质量及其功能特性进行了比较研究,初步结论为:浓缩物的氨基酸含量及组成较螺旋藻粉有很大提高;浓缩物的水吸附能力较螺旋藻粉为差,而脂肪吸附能力、乳化能力和起泡能力均优于原藻粉。     

Determination of total glucosinolates in oilseed rape by X-ray spectrometric analysis for oxidised sulphur (S6+)

A rapid X-ray spectrometric (XRS) method has been developed for the determination of the total glucosinolate content of oilseed rape and other Brassica oilseeds. The method is based on analysis for fully oxidised sulphur (S⁶⁺), which includes half the sulphur (S) in the glucosinolate molecule, and the S in sulphate. Results are highly correlated with glucosinolate content determined by glucose release, a standard method widely used in Australia. The relationship is total glucosinolates = (23·97 S⁶⁺ -9·43) r² = 0·987, where the glucosinolate content is expressed as μmol g^?1 and the S⁶⁺ content in mg g^?1. The relationship is applicable to seed of any glucosinolate content and to meal, and is unaffected by changes in protein sulphur content. The correlation of glucosinolates with S⁶⁺ is shown to be closer than the correlation with total S. The latter correlation forms the basis of the existing XRS method, used within the European Community in recent years. The advantages of S⁶⁺ derive from the linearity of the regression and the elimination of errors caused by variation in protein content. The method should be valuable to the Australian oilseed industry because it allows the rapid screening of breeding lines to ensure low glucosinolate content and the assessment of deliveries for crushing and of meal.     

Gravimetric determination of tannins and their correlations with chemical and protein precipitation methods

Abstract. A method for gravimetric determination of tannins based on binding with insoluble polyvinylpyrrolidone (PVP) is presented. The gravimetric method gives the absolute amount of tannins and avoids problems of standards associated with spectrophotometric methods. The method was applied to nine browse and tree leaves. The values obtained correlate significantly with tannins determined spectrophotometrically, protein precipitation capacities and protein precipitable phenotics. This method together with other tannin assays will be useful in nutritional studies. The present study also demonstrates the different behaviour of tannic acids from different commercial sources towards PVP suggesting the presence of different moieties in tannic acids from different commercial sources and even among batches from the same source thereby affecting the results obtained using the spectrophotometric methods. Use of well-defined tannic acid as a standard in spectrophotometric methods is suggested which will allow meaningful comparison of values obtained from different laboratories.     

Time-dependent competitive adsorption of milk proteins and surfactants in oil-in-water emulsions

Competitive adsorption of pure milk proteins and non-ionic surfactants has been studied in model oil-in-water emulsions (4 g kg^?1 β-lactoglobulin or β-casein, 200 g kg^?1 n-hexadecane) as a function of the age of the adsorbed protein layer at the oil-water interface. With β-lactoglobulin-stabilised emulsions containing oil-soluble surfactant C₁₂ E₂ (diethylene glycol n-dodecyl ether), there is found to be a steadily increasing amount of protein associated with the emulsion droplets over a few hours following emulsification. Addition of water-soluble surfactant Tween 20 (polyoxyethylene (20) sorbitan monolaurate) to a β-lactoglobulin-stabilised emulsion (with or without C₁₂E₂) leads to less protein displacement if the emulsion is aged prior to addition of Tween 20. Moderate additions of C₁₂E₂ or Tween 20 produce no time dependence in the competitive adsorption in β-casein-stabilised emulsions, although some time dependence is observed when C₁₂E₂ and a high concentration of Tween 20 are present together. Crystallisation of the oil phase in β-casein-stabilised emulsions at pH 7 leads to a lowering of the measured protein surface concentration, especially in the presence of C₁₂E₂ and a reduction in the surfactant to protein molar ratio required for complete protein displacement by water-soluble surfactant (Tween 20 or octaethylene glycol n-dodecyl ether). Under more acidic conditions of pH 5 or pH 3, the surface coverage and ease of displacement of β-lactoglobulin at the surface of liquid emulsion droplets is substantially different from that under neutral pH conditions.     

从猪血浆蛋白质中制备无色蛋白胶

使用凝聚剂从猪血浆蛋白质中获得无色蛋白胶。通过用随机质心最优化方法找到分离最优条件为:pH3.7～3.9,№Cl浓度0.24～0.26mol/l,凝聚剂浓度1.1～1.3％,在最优化条件下制备的无色蛋白胶中蛋白质浓度几乎是猪血浆蛋白质浓度的三倍。测定了无色蛋白胶的功能特性并应用于仿真鱼圆和酸乳。