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21.
Afam I Jideani Richard K Owusu Apenten H G Muller 《Journal of the science of food and agriculture》1994,65(4):465-476
The effect of cooking on proteins from acha and durum wheat was assessed from an analysis of protein extractability, gel electrophoretic profiles, in-vitro protein digestibility (IVPD) and the amino acid compositions of wholemeal flour and residue proteins. Heating wholemeal flour samples at 100–140°C (t = 10–40 min) resulted in 0–30% and 45–55% decreases in acha and durum protein solubility, respectively. In general, high molecular weight (30–70 k Da) protein subunits were more susceptible to heat damage. For both cereals, sodium dodecyl sulphate (SDS; 10 g litre?1) and/or dithiothrcitol (DTT; 10 mM ) increased protein solubility in unheated and heated samples. The IVPD index was 90–91% and was not significantly altered by cooking (100–120°C, t = 40 min). Cooking at extreme temperatures (140°C, t = 40 min) reduced the IVPD by 8% (P = 0.05). Osborne fractionation resulted in a durum or acha residue level of 7.8% or 55.2%. Treatment with solvent containing propanol, SDS and/or DTT at room temperature followed by SDS-polyacrylamide gel electrophoresis of non-solubilised proteins showed that the glutelin fraction of acha, with the exception of a 65 kDa subunit, was insoluble owing to strong inter-subunit hydrophobic and disulphide interactions. Wholemeal acha flour and residue protein showed a significantly greater level of hydrophobic and sulphur amino acids as well as glutamine which is associated with H-bonding. The possibility that cereal protein solubility is also dependent on protein-carbohydrate links is discussed. 相似文献
22.
康山金矿地质地球化学特征及其成因 总被引:3,自引:1,他引:2
康山金矿产在豫西熊耳山古隆起区的结晶基底太华群和盖层中元古界熊耳群地层接触界面附近,矿体严格受构造破碎蚀变带控制。流体包裹体,稳定同位素等研究表明,成矿物质来自太华群变质岩,成矿流体的性质与变质热液截然不同,而与花岗岩浆热液相近似。该矿床的形成与燕山期发生的同构造-花岗岩浆期热液活动有关,金沉淀成矿阶段有大气水的混入。 相似文献
23.
谢意红 《宝石和宝石学杂志》2002,4(4):28-31
市场上出现的紫色、浅紫色、浅黄色、粉红色、酒黄色、黄褐色、红色人造立方氧化锆均为亚金刚光泽, 火彩明显; 密度为5.99~6.34 g/cm3, 相对硬度为8~9; 除粉红色者表现出非均质性和弱多色性且内含大量定向排列的白色脱溶物外, 其余的为均质性, 内部洁净; 不同颜色的立方氧化锆的吸收光谱、紫外荧光以及滤色镜下的变色情况均存在差异; 浅紫色立方氧化锆的吸收光谱特征表明它是Nd致色. 能谱分析结果表明: 彩色立方氧化锆的常见元素有Zr, Y, P, Hf, Ca等; Er, Ce, Fe分别是粉红色、红色、酒黄色立方氧化锆的致色元素; 当Y2O3的摩尔分数大于或近于7%时, 立方氧化锆为立方面心结构且内部洁净; 当Y2O3的摩尔分数小于5%时, 立方氧化锆表现为非均质性且内含大量定向分布的白色脱溶物. 用拉尔森改写的格拉斯顿-代尔公式计算其近似折射率为2.12~2.19. 相似文献
24.
本文介绍了一种新型的针刺延期药的配方设计和制备工艺,这种低猛度高热量的针刺延期药具有较高的发火感度,可满足一定的延期时间和相容性要求。文中还介绍了它在几种小型针刺延期雷管中的应用。 相似文献
25.
M. Safar D. Bertrand P. Robert M. F. Devaux C. Genot 《Journal of the American Oil Chemists' Society》1994,71(4):371-377
The combination of attenuated total reflectance (ATR) and mid-infrared spectroscopy (MIRS) with statistical multidimensional
techniques made it possible to extract relevant information from MIR spectra of lipid-rich food products. Wavenumber assignments
for typical functional groups in fatty acids were made for standard fatty acids: Absorption bands around 1745 cm−1, 2853 cm−1, 2954 cm−1, 3005 cm−1, 966 cm−1, 3450 cm−1 and 1640 cm−1 are due to absorption of the carbonyl group, C−H stretch, =CH double bonds of lipids and O−H of lipids, respectively. In
lipid-rich food products, some bands are modified. Water strongly absorbs in the region of 3600–3000 cm−1 and at 1650 cm−1 in butters and margarines, allowing one to rapidly differentiate the foods as function of their water content. Principal
component analysis was used to emphasize the differences between spectra and to rapidly classify 27 commercial samples of
oils, butters and margarines. As the MIR spectra contain information about carbonyl groups and double bonds, the foods were
classified with ATR-MIR, in agreement with their degree of esterification and their degree of unsaturation as determined from
gas-liquid chromatography analysis. However, it was difficult to differentiate the studied food products in terms of their
average chainlength. 相似文献
26.
Low carbon steel was oxidized over the temperature range 1000‐1250°C in O2‐CO2‐H2O‐N2, O2‐H2O‐N2, and O2‐CO2‐N2 gas mixtures. Oxidation times were 12‐120 min. and the scales were 50‐2000 μm thick. The variations of these parameters were chosen to elucidate the phase composition of oxide scales under conditions similar to those of reheating furnaces in hot strip mills, using either thin slab casting or conventional casting and rolling technology. Two types of scales have been observed which are influenced by the furnace atmosphere, oxidation time, and temperature. The first type is a crystalline scale with an irregular outer surface, composed mostly of wustite (FeO), and a negligible amount of magnetite (Fe3O4). The second type is the classical three‐layer scale, composed of wustite (FeO), magnetite (Fe3O4), and hematite (Fe2O3). In general, the experiments showed that an increase in oxidation time decreased the percentage of wustite while the percentages of magnetite and hematite increased. A rise in oxygen concentration in the gas mixture increased the percentages of magnetite and hematite, confirming earlier experimental findings. In water vapour‐free atmospheres O2‐CO2‐N2, the oxide scales had a low percentage of wustite, and high percentage of magnetite and hematite. Carbon dioxide showed a small influence at 1100°C, and a negligible one at 1250°C. 相似文献
27.
高放废液化学成分分析 总被引:3,自引:0,他引:3
概述了高放废液中25种阳离子、5种阴离子以及总蒸残物、总氧化物、密度和游离酸的分析方法。对核燃料后处理高放废液进行取样分析,其主要化学成分采用两种以上不同原理的方法作对比测定,结果相互符合情况良好,为高放废液处理处置研究设计,提供了完整、准确的基础数据。 相似文献
28.
It has recently been shown that authenticated Byzantine agreement,
in which more than a third of the parties are corrupted, cannot be
securely realized under concurrent or parallel (stateless)
composition. This result puts into question any usage of
authenticated Byzantine agreement in a setting where many
executions take place. In particular, this is true for the whole
body of work of secure multi-party protocols in the case that a
third or more of the parties are corrupted. This is because these
protocols strongly rely on the extensive use of a broadcast
channel, which is in turn realized using authenticated Byzantine
agreement. We remark that it was accepted folklore that the use of
a broadcast channel (or authenticated Byzantine agreement) is
actually essential for achieving meaningful secure multi-party
computation whenever a third or more of the parties are corrupted.
In this paper we show that this folklore is false. We present a
mild relaxation of the definition of secure computation allowing
abort. Our new definition captures all the central security issues
of secure computation, including privacy, correctness and
independence of inputs. However, the novelty of the definition is
in decoupling the issue of agreement from these issues. We
then show that this relaxation suffices for achieving secure
computation in a point-to-point network. That is, we show that
secure multi-party computation for this definition can be achieved
for any number of corrupted parties and without a
broadcast channel (or trusted pre-processing phase as required for
running authenticated Byzantine agreement). Furthermore, this is
achieved by just replacing the broadcast channel in known
protocols with a very simple and efficient echo-broadcast
protocol. An important corollary of our result is the ability to
obtain multi-party protocols that remain secure under composition,
without assuming a broadcast channel. 相似文献
29.
The aim of this study was to bring to the surface the strategic use of imitative processes in the context of a 2-route model: (a) direct imitation, used in reproducing new, meaningless actions, and (b) imitation based on stored semantic knowledge of familiar meaningful actions. Three experiments were carried out with healthy participants who reproduced meaningful and meaningless actions within an established time limit. The study investigated 3 factors that could potentially affect the selection of processes used for imitation: (a) the composition of the experimental list (blocked or mixed presentation), (b) the presence-absence of instructions (Experiments 1 and 2), and (c) the relative proportions of the stimuli (Experiment 3). Overall, the results suggest that each of these factors influences the selection of imitative strategies in healthy individuals with temporarily reduced capacities, as happens in the case of brain-damaged patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
30.
In this study, a single unit of planar micro-solid-oxide fuel cell (μSOFC) is investigated numerically to evaluate the influences of flow channel design, oxygen composition, and thermal operating conditions on cell performance. Four flow channel designs are examined under the co-flow configuration: serpentine, double serpentine, rod bundle, and oblique rib. For all designs, the contacts areas of interconnect to electrodes are kept consistent to maintain the ohmic losses at the same level. To characterize the mass transport effects, there are three different compositions, 100% O2, 50% O2/50% N2 and air, fed to the cathode inlet. Different thermal conditions, adiabatic and isothermal, are applied to the outer boundary of the μSOFC and the results are compared. The outcomes suggest that both thermal conditions and oxidant composition show remarkable influences on μSOFC performance. Under adiabatic conditions, the rise of cell temperature causes a decrease in reversible voltage, deteriorating the overall cell competence. When oxygen is diluted with nitrogen, local gas diffusion becomes dominant to the cathode reaction. Bulk flow, on the other hand, plays a minor role in cell performance since there is little deviation in the polarization curves for all flow channel designs, even at high current densities. For comparison, the flow visualization technique is employed to observe the transport phenomena in various flow channel designs. The flow patterns are found to resemble the concentration distribution, providing a useful tool to design μSOFCs. 相似文献