超薄壁大径厚比屏蔽套反旋模拟分析

建立了超薄壁大径厚比屏蔽套反旋工艺弹塑性有限元分析的力学模型,利用大型有限元分析软件MSC.Marc进行了仿真分析,研究了旋轮接触区金属的塑性流动场以及应力应变的分布规律,从而为实际加工超薄壁大径厚比屏蔽套时提供理论指导。     

酶改性大豆分离蛋白在冰淇淋生产中的应用

探讨转谷氨酰胺酶改性大豆分离蛋白的乳化特性及其在冰淇淋生产中的应用。确定改性大豆分离蛋白冰淇淋的配方为：白砂糖12%,奶粉8%,奶油3%,改性大豆分离蛋白3%,CMC 0.1%,单甘酯0.1%,明胶0.2%。由此制得的冰淇淋膨胀率、融化率和感官指标均比较理想。较普通冰淇淋相比,减少了奶粉、乳化剂和稳定剂的用量,提高了冰淇淋的营养价值,降低了生产成本。     

大豆分离蛋白的凝胶稳定性的研究进展

大豆分离蛋白因其蛋白质含量高,具有凝胶性等多种功能特性,在食品工业中得到广泛应用。但大豆分离蛋白在贮藏过程中,其凝胶的稳定性往往下降,严重地影响了产品的质量。国内外研究发现,在贮藏过程中蛋白组成成分、蛋白浓度、温度、pH 值和离子强度等的变化对凝胶形成具有一定影响,通过各种改性方法可以提高大豆蛋白的凝胶稳定性。     

Heightened conflict in cue-target translation increases backward inhibition in set switching.

Backward inhibition (BI) is a performance cost that occurs when an individual returns to a task after 1 (vs. more than 1) intervening trial, and it may reflect the inhibition of task-set components during switching. In 3 experiments, we support the theory that inhibition can target cue-based preparatory stages of a task. Participants performed a cued target-localization task that had been previously shown to produce BI. In Experiment 1, reassignment of arbitrary cue-target pairings midway through the experiment doubled the size of BI, though cue, target, and response sets remained unchanged. In Experiment 2, we controlled for effects of order of conditions or simple change of cue meaning. In Experiment 3, we demonstrated that the effect depends on re-pairing members of the same cue and target sets. The results are attributed to heightened conflict (and hence greater inhibition) during cue-target translation when a previously learned cue-target mapping is remapped. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

针对Ad Hoc网络组播组发现的蚁群算法

针对将蚁群算法应用于Ad Hoc网络组播寻路中存在无法同时找到多目标的局限性,提出了一种采用逆向寻路的解决方案。当前进蚂蚁在到达接收端时,会自动复制出若干个返回蚂蚁并进行回溯,而这些返回的蚂蚁并不是按原路返回,而是进行反向的寻路,同时原前进蚂蚁将继续寻找其他多目标并进行相同的操作。仿真结果与原始蚁群算法进行了比较,可以发现在延迟、带宽消耗、发包数上逆向蚁群算法要优于原始蚁群算法。仿真实验表明,改进的蚁群算法减少了为寻找多目标所造成的延迟,并且提高了算法的收敛速度。     

Protein concentrate from Jatropha curcas screw‐pressed seed cake and toxic and antinutritional factors in protein concentrate

BACKGROUND: Jatropha curcas seeds are highly toxic to livestock. The presence of phorbol esters and antinutrients such as trypsin inhibitor, lectin and phytate and the high level of shells in the seed cake prevent its use in animal diets. Using the principle of isoelectric precipitation, the conditions for preparation of the protein concentrate from oil‐containing seed cake and defatted seed cake were optimised and the contents of phorbol esters and antinutrients were determined. RESULTS: The recovery of protein concentrate was highest when the proteins from the seed cakes were solubilised at pH 11 for 1 h at 60 °C and the precipitation of these proteins was done by lowering the pH to 4. Under these conditions, over 53% of the total proteins present in the seed cakes were recovered in the protein concentrates. The protein contents in the protein concentrates obtained from the oil‐containing seed cake and defatted seed cake were 760 and 820 g kg^?1 respectively. Substantial amounts of phorbol esters were present in the protein concentrates (0.86–1.48 mg g^?1). Trypsin inhibitor was present at an approximately tenfold higher level in the protein concentrates than in the seed cakes. Lectin and phytate were also present at high levels, but their levels were lower than in the seed cakes. Tannins were present in negligible amounts. CONCLUSION: To make the protein concentrate from Jatropha seed cake fit for use as an ingredient in livestock feed, phorbol esters must be removed and trypsin inhibitor and lectin inactivated by heat treatment. The adverse effects of phytate could be mitigated by addition of phytase in the diet. Copyright © 2008 Society of Chemical Industry     

Characterization,amino acid composition and in vitro digestibility of hemp (Cannabis sativa L.) proteins

The protein constituents and thermal properties of hemp (Cannabis sativa L.) protein isolate (HPI) as well as 11S- and 7S-rich HPIs (HPI-11S and HPI-7S) were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and different scanning calorimetry (DSC), and their amino acid composition and in vitro digestibility were also evaluated, as compared to soy protein isolate (SPI). SDS-PAGE analysis showed that the edestin (consisting of acidic and basic subunits, AS and BS) was the main protein component for HPI and HPI-11S, while HPI-7S was composed of the BS of edestin and a subunit of about 4.8 kDa. DSC analysis characterized thermal transition of the edestin component and the possible present form of different subunits. Except lysine and sulfur-containing amino acids, the essential amino acids of various HPIs met the suggested requirements of FAO/WHO for 2–5 year old infants. The proportion of essential amino acids to the total amino acids (E/T) for HPI (as well as HPI-11S) was significantly higher than that of SPI. In an in vitro digestion model, various protein constituents of various HPIs were much easily digested by pepsin plus trypsin, to release oligo-peptides with molecular weight less than 10.0 kDa (under reduced condition). Only after pepsin digestion, in vitro digestibility of HPIs was comparable to that of SPI, however after pepsin plus trypsin digestion, the digestibility (88–91%) was significantly higher than that (71%) of SPI (P < 0.05). These results suggest that the protein isolates from hempseed are much more nutritional in amino acid nutrition and easily digestible than SPI, and can be utilized as a good source of protein nutrition for human consumption.     

Thermal behavior of emulsions manufactured with soy protein ingredients

The conformation, denaturation and aggregation behavior of proteins are important factors which dictate their ingredient functions and applications in formulated food products. The effect of variation in pre-treatment temperature (70–90 °C × 30 s), pH (6.4–7.5) and calcium supplementation (450 and 850 mg/L) on heat coagulation time (HCT at 140 °C) of model emulsions (3.6% (w/v) protein) stabilized with soy protein isolate (SPI) and soy protein hydrolysate (SPH) ingredients was determined. Generally, HCT of emulsions was not significantly affected by alteration of constituent pre-heating temperatures. Model emulsions displayed higher HCTs with increasing pH and lower levels of intrinsic ash content. At both supplementation levels, calcium addition led to decreased HCTs. Supplementation with chloride salts caused a greater decrease in HCT compared to supplementation with citrate salts. Furthermore, soy protein hydrolysis was associated with lower emulsion thermal stability. Results demonstrate that modification of ingredient and manufacturing parameters may be a useful approach for enhancing thermal stability properties of soy protein stabilized emulsions.     

改进的抵抗离线字典攻击的口令更新协议

口令认证是最简单,方便和应用最广泛的一种用户认证方式。最近,Tsaur等人指出了Chang等人的口令更新协议存在拒绝服务攻击并且不能提供口令的后向安全。随后,他们给出了一种改进的口令更新协议,并声称该协议是安全的。文中,分析了Tsaur等人的口令更新协议,指出了其方案是易受离线字典攻击的,且不能提供口令的前向和后向安全性。最后,提出一种改进的口令更新协议,并分析其安全性。     

Rigid polyurethane foams based on activated soybean meal

Soybean meal (SM), an abundant biomass resource, was used as the surrogate to partially replace polyols in rigid polyurethane foam synthesis. Compared with polyurethanes based on other soybean‐based resources, such as soybean protein isolate (SPI), polyurethane foams based on activated SM showed better thermal and mechanical properties. The amount of SM in the final polyurethane foams can be as high as 30 wt % (base on the total weight of foam), which dramatically decreases the cost of the foams. The results also showed that SM played a vital role in improving the foam properties, which could be attributed to the participation of the functional groups in SM in the polyurethane foam synthesis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012