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51.
Bacillus subtilis JM‐3 was isolated from anchovy sauce naturally fermented in an underground cellar at 15 ± 3C for 3 years. The activity of the B. subtilis protease was highest in the 40–60% ammonium sulfate fraction. The yield of the purified protease was 5.3%, and its purification ratio was 35.6 folds. The molecular weight of the B. subtilis protease was 17.1 kDa, and its Km and Vmaxvalues were 1.75 μg/mL and 318 μM 1/min, respectively. The optimal temperature for protease activity was 60C, but optimal stability temperature was 30C. The optimal pH for protease activity and stability was 5.5. Therefore, the B. subtilis JM‐3 protease was classified as an acid protease. The relative activities of the B. subtilis JM‐3 protease were 69, 21 and 1.3% at 10, 20 and 30% NaCl concentrations, respectively. The best substrate for the B. subtilis JM‐3 protease was benzyloxycarbonyl‐glycine‐p‐nitrophenyl ester followed by bovine serum albumin. p‐Toluene‐sulfonyl‐L‐lysine chloromethylketone was the strongest inhibitor followed by soybean trypsin inhibitor, but N‐ethylmaleimide did not inhibit this enzyme. The B. subtilis JM‐3 protease was therefore presumed to be a trypsin‐like serine protease. 相似文献
52.
53.
以大豆7S和11S球蛋白为研究对象,采用纳米二氧化硅(SiO2)对其进行分子修饰,添加量分别为蛋白基料的0.5%、1.0%、1.5%,然后用1、3、5 mol/L尿素控制变性相结合的方法来提高7S与11S球蛋白在3种木材(水曲柳、樱桃木、松木)上的胶黏强度。结果表明,经纳米SiO2修饰后,大豆7S和11S球蛋白的胶黏强度明显增大,最佳添加量为1%;当浓度为1 mol/L的尿素与1%的纳米SiO2共同修饰7S和11S球蛋白后,其胶黏强度最大。同时采用差示扫描量热仪测定了大豆球蛋白修饰前后的焓变,并探讨了胶黏作用增强的可能机理。 相似文献
54.
55.
USE OF OZONE TO INACTIVATE MICROORGANISMS ON LETTUCE 总被引:6,自引:0,他引:6
When ozone (1.3 mM) was bubbled for 3 min in a mixture of shredded lettuce and water, counts ofmesophilic andpsychrotrophic bacteria decreased 1.4 and 1.8 log10 cfu/g, respectively. Counts of these microorganisms on lettuce, from a different batch, decreased 3.9 and 4.6 log, respectively, during 5 min of ozone treatment. Shredded lettuce was treated with gaseous ozone, or mixed with aqueous solution of ozone (1:20 w/w) with or without bubbles. For effective delivery of ozone, stirring (low and high speed), sonication or stomaching was applied during the ozonation. Washing the lettuce with water only decreased total count on shredded lettuce by 0.74–1.0 log cfu/g. When lettuce in a treatment chamber was flushed with gaseous ozone, the total count decreased 0.85 log cfu/g, but when vacuum was applied before the ozone flush, the total count decreased 0.96 log cfu/g. Bubbling ozone in water-lettuce mixture while sonicating, high-speed stirring, or before stomaching inactivated 1.4, 1.9 and 1.9 log cfu/g, respectively. In conclusion, bubbling gaseous ozone in water is the most effective ozonation method. Efficient ozone delivery to microorganisms on lettuce requires a combination of ozone bubbling and high-speed stir. 相似文献
56.
Compatible phases in the system Li2 O-Al2 O3 -TiO2 at various temperature levels were determined mainly by solid-state reactions for the portion of the ternary system bounded by Li2 O Al2 O2 , Li2 O.TiO2 , Al2 O, and TiO2 . The existence of a ternary compound, Li2 O.Al2 O3 .4TiO2 , and nine joins was established. The ternary compound has a lower limit of stability at 1090°± 15°C. and dissociates and recombines rapidly at 1380°± 15°C. 相似文献
57.
Masazumi OKIDO Ryoichi ICHINO Seong-Jong KIM Seok-Ki JANG 《中国有色金属学会会刊》2009,19(4):892-897
The chemical conversion coating was formed on Mg alloy for low cost and harmlessness in environment by using the colloidal silica as the main component. The film formed at 298 K was thick, which was thought to be the combination of Si and O. In salt spray test, the ratio of black rust on the specimen that did not conducted chemical conversion treatment was five times or more than those of the chemical conversion treated specimen. The film of chemical conversion coating produced by alkali treatment process was thinner than the specimen produced in basic chemical conversion treatment solution. 相似文献
58.
Myeong-Hoon LEE Yeon-Won KIM Kyung-M in LIM Seung-Hyo LEE Kyung-Man MOON 《中国有色金属学会会刊》2013,23(3):876-880
锌合金镀层由于具有较强的耐腐蚀性能而得到广泛的关注,特别是Zn-Mg合金镀层,其耐腐蚀性能能得到显著提高。采用气相沉积方法制备不同镁含量的Zn-Mg合金镀层,研究Zn-Mg合金镀层中镁含量对其耐腐蚀性能的影响。在3%NaCl溶液中进行浸泡试验、动电位测试和电偶腐蚀试验,研究不同Mg含量镀层的耐腐蚀性能。结果表明,Zn-Mg合金镀层的耐腐蚀性能与Mg含量显著相关,镀层的腐蚀电位随着Mg含量的增加而降低,但是腐蚀电流密度却升高,直至15%Mg含量;在Zn-Mg合金镀层中存在钝化区。 相似文献
59.
Several automotive parts such as door panels have been manufactured by using load-adapted blanks for crash optimization and weight minimization.Recently, Tailor Rolled Blanks (TRB) has been introduced to remove the disadvantages of a welding process which was used in joining panel components.TRB offers better structural design capabilities due to the seamless transitions on the panels with different thicknesses.In spite of the advantages of the process, TRB leaves internal stresses in the panel.This residual stresses lower the formability of Tailor Rolled Blanked (TRBed) parts and cause cracks near severe curvature during subsequent forming processes.In this research, the residual stresses of TRBed Al5J32-T4 sheets were studied by X-ray stress analysis, and also microstructure was observed along the rolling direction.In addition, heat treatment was done after TRB process in order to compare the residual stresses to that of the TRBed sheets before the heat treatment. 相似文献
60.
Daily meat consumption produces a lot of bone waste, and dumped bone waste without treatment would result in environmental hazards. Conventional treatment methods of waste bones have some disadvantages. Herein, an investigation of bone waste treated using thermal plasma technology is presented. A high-temperature plasma torch operated at 25.2 kW was used to treat bone waste for seven minutes. The bone waste was finally changed into vitric matter and lost 2/3 of its weight after the treatment. The process was highly efficient, economical, convenient, and fuel-free. This method could be used as an alternative for disposal of bone waste, small infectious animals, hazardous hospital waste, etc. 相似文献