Low-cost preparation and frictional behaviour of a three-dimensional needled carbon/silicon carbide composite

A low-cost carbon/silicon carbide (C/SiC) composite was manufactured by phenolic resin impregnation–pyrolysis combined with liquid silicon infiltration. The carbon fiber preform was prepared by three-dimensional needling. A carbon/carbon composite with a density of 1.22 g/cm³ after only one impregnation–pyrolysis cycle was achieved by using hot-pressing curing. The density of the final C/SiC was 2.10 g/cm³ with a porosity of 4.50% and SiC-content of 45.73%. The C/SiC composite had a high thermal conductivity of 48.72 W/(m K) perpendicular to the friction surface and demonstrated good friction and wear properties. The static and average dynamic friction coefficients were 0.68 and 0.32 (at a braking velocity of 28 m/s). The weight wear rates of the rotating disk and stationary disk were respectively 7.71 and 5.60 mg/cycle with linear wear rates, 1.67 and 1.22 μm/cycle, at a braking velocity of 28 m/s.     

一种SCWR概念设计方案的系统水动力特性

对一种典型的超临界水堆(SCWR)设计方案中的反应堆冷却剂系统(RCS)和非能动余热排出系统(PRHRS)回路进行了简化,建立了两系统在超临界压力下的统一水动力模型。利用模型对SCWR主系统和非能动余热排出系统的水动力特性及输热、排热能力进行了计算,并在此基础上分析了堆芯进口温度、泵特性、回路高度、系统阻力等因素对系统运行的影响。     

多规合一的实用性村庄规划

改革开放40年,中国城镇化高速发展,与此同时,城乡二元结构在不断加剧,城乡两极差异化格局在不断显现,乡村总体上处在落后、萧条、衰败的状况。这个状况不是中国所独有,发达国家的乡村在当年高速城镇化时期也面临着一样的挑战。今天,落后、衰败、萧条的乡村正在成为制约中国实现世界强国目标的关键短板,也成为中国许多经济社会甚至是政治问题产生的根源。乡村虽小,但可谓"小乡村,大问题",要解决乡村问题需要置于一个大格局、大系统,我们也要有更高的视野。     

汽蒸爆破麦草浆H2O2漂白的研究

主要是对汽蒸爆破麦草浆的漂白可行性及H2O2漂白的最佳工艺进行了探讨.实验表明,汽蒸爆破麦草浆在合适的工艺条件下可从8%ISO漂白至73%ISO白度,且返黄值低.漂白浆可满足各种中低档文化、生活用纸的用浆要求,而且H2O2漂白环境污染负荷少,可取代传统的CEH漂白方法.     

猪血亚硝基血红蛋白坚牢度的研究

对亚硝基血红蛋白的坚牢度进行了系统研究。研究结果表明,亚硝基血红蛋白色素耐热性强,可用于高温肉制品着色;该色素在弱酸性及中性环境中色泽稳定,耐光性强;金属离子对亚硝基血红蛋白溶液色泽无影响;还原剂对其色泽无影响,但耐H2O2能力差;蔗糖不影响亚硝基血红蛋白的色调和色度。     

Yak milk casein as a functional ingredient: preparation and identification of angiotensin-I-converting enzyme inhibitory peptides

Yak milk casein derived from Qula, a traditional Tibetan acid curd cheese, was hydrolyzed by six commercially available proteases (Trypsin, Pepsin, Alcalase, Flavourzyme, Papain and Neutrase). These hydrolysates were assayed for their inhibitory activity of Angiotensin-I-converting enzyme (ACE). The hydrolysates obtained by Neutrase from Bacillus amyloliquefaciens showed the highest ACE inhibitory activity. The IC50 value of Neutrase-hydrolysate was 0.38 mg/ml. The hydrolysate obtained by Neutrase was further separated by consecutive ultra-filtration with 10 kDa and then with 6 kDa molecular weight cut-offs into different permeated parts and fractionated by gel filtration chromatography with a Sephadex G-25 column. The active fraction was subjected to RP-HPLC, in which five peaks were purified and identified. Amino acid sequence analysis confirmed that the peptides and origins were as follows: YQKFPQY (alphas2-CN; f89-95), LPQNIPPL (beta-CN; f70-77), SKVLPVPQK (beta-CN; f168-176), LPYPYY (kappa-CN; f56-61) and FLPYPYY (kappa-CN; f55-61). Their amino acid sequences matched well with those of known bioactive peptides from bovine casein. The results indicated that yak milk casein could be a resource to generate antihypertensive peptides and be used as multifunctional active ingredients for many value-added functional foods as well as a traditional food protein.     

印度麦草制浆碱回收技术及设备考察报告

印度多年来致力于发展草浆造纸。印度思来亚集团(Shreyans Group,India)是印度大企业集团,是印度第一家将流化床技术用于碱回收的公司。此文是一份对印度麦草制浆碱回收的湿法备料和连续蒸煮系统;蒸发技术和蒸发皿;低温焚烧炉的技术及设备考察报告,对我国中小造纸企业会有所借鉴。     

巴马火腿红色色素的研究进展

综述了巴马火腿红色色素研究的最新进展。巴马火腿在腌制时不添加硝酸盐或亚硝酸盐 ,经过长期的加工过程 ,巴马火腿肉具有稳定的红色。巴马火腿的红色色素与添加硝酸盐或亚硝酸盐腌制的普通火腿的红色色素具有不同的吸收光谱、颜色稳定性和抗氧化性。根据巴马火腿红色色素的吸收光谱、荧光光谱、高压液相色谱和高分辨率电喷雾电离质谱 ,证实了巴马火腿的红色色素是锌 原卟啉IX。     

In vitro reconstitution of antimicrobial pathogen activity by expressed recombinant bovine lactoferrin N-terminal peptide in Escherichia coli

Recombinant bovine lactoferrin N-terminal polypeptide (rbLF-N) Escherichia coli expression system was constructed and the rbLF-N antimicrobial activity was displayed by enzymatic proteolysis in this study. A 162 bp 5'-terminal fragment of bovine lactoferrin (bLF) gene from bovine liver gDNA was amplified by PCR. The DNA fragment containing exon-2 of the bLF gene was cloned into the expression vector pGEX-4T1 and the glutathione-S-transferase-rbLF-N (GST-rbLF-N) fusion protein was obtained by over-expression in Esch. coli BL21(DE3). After thrombin/pepsin digestion, the rbLF-N was released from the fusion protein. The recombinant peptide was separated and identified by SDS-PAGE, HPLC and LC-MS/MS analysis. A very strong anti-food-born microbial pathogen activity of the rbLF-N peptides was displayed through bio- and kinetic-assays in vitro. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the rbLF-N peptide for bacterial pathogens Staphylococcus aureus, Streptococcus mutans, Esch. coli and Klebsiella pneumoniae were 11.7, 11.7, 11.7, 23.4 microg and 23.4, 11.7, 11.7, 46.4 microg, respectively. This study created a new route for exploring lactoferrin peptide application in food science.     

Flexural strength and wear resistance of C/C–SiC brake materials improved by introducing SiC ceramics into carbon fiber bundles

In this work, we adopted PIP technology to introduce SiC ceramics into the carbon fiber bundles of C/C–SiC composites. The obtained C/C–SiC composites containing PIP-SiC exhibited improved flexural strength. Meanwhile, the strength difference was reduced in in-plane and vertical directions. Fracture morphology revealed that the introduction of SiC into the fiber bundles broadened available toughening mechanism of the prepared composites. The braking performance of the materials was tested on an MM-1000 dynamometer. After braking at different speeds, we analyzed wear rates, variations in friction coefficient, and the morphological evolution of the friction surface. The results indicated that the introduction of SiC into the fiber bundles enhanced the abrasive resistance of local C/C regions, which yielded a significant reduction of the wear rates.