RRPP以太环网保护协议

RRPP是一个专门应用于以太环网的链路层协议,可以防止环路上的广播风暴,具有快速收敛的特点.     

网络环路故障处理

随着近年来计算机网络的飞速发展,网络在各行各业得到了广泛的应用,如何能够让网络平稳运行,做好网络的日常维护,成为计算机网络维护人员的重要工作。网络环路是我们经常遇到的一种网络故障,一旦发生环路,将造成整个网络瘫痪无法使用。文章对网络环路的分类、网络环路避免方法进行了介绍,并通过网络环路处理实例讲解了网络环路的处理方法。     

Four permeases import proline and the toxic proline analogue azetidine-2-carboxylate into yeast

We have found that proline and the toxic proline analogue azetidine-2-carboxylate (AzC) are efficiently imported into Saccharomyces cerevisiae cells by four amino acid permeases, including two nitrogen-regulated permeases (PUT4 and GAP1) and two permeases that are regulated by the SPS sensor of extracellular amino acids (AGP1 and GNP1). In contrast to Agp1p, Gnp1p is not functionally expressed when cells are grown on media containing proline as sole nitrogen source. These findings have implications for the interpretation of studies using AzC to characterize nitrogen source-dependent regulation of amino acid uptake and of post-Golgi targeting and localization of amino acid permeases in yeast.     

STP超薄真空保温板的性能与应用

STP超薄真空保温板是由超细二氧化硅、添加剂、助剂配置而成的芯材与高强度复合阻气膜通过抽真空封装技术复合后制成的一种超薄型保温板。其热导率低于0.008 W/（m·K）,防火性能达到A级,但在施工过程中,受环境影响较大,不能现场剪裁,板材易受损,使用寿命不稳定。阐述了STP超薄真空保温板的构造原理、性能特点,以及与传统保温材料的性能比对,根据其在外墙保温系统中的应用和存在问题,建议将STP超薄真空保温板作为保温芯材,通过复合外饰面层（如金属饰面）制成保温装饰一体化板。     

Modifications of carbon for polymer composites and nanocomposites

The various forms of carbon used in composite preparation include mainly carbon-black, carbon nanotubes and nanofibers, graphite and fullerenes. This review presents a detailed literature survey on the various modifications of the carbon nanostructures for nanocomposite preparation focusing upon the works published in the last decade. The modifications of each form of carbon are considered, with a compilation of structure-property relationships of carbon-based polymer nanocomposites. Modifications in both bulk and surface modifications have been reviewed, with comparison of their mechanical, thermal, electrical and barrier properties. A synopsis of the applications of these advanced materials is presented, pointing out gaps to motivate potential research in this field.     

磷酸酯型两性淀粉的制备、性能及其在造纸中的应用

以阳离子淀粉DM933A和多聚磷酸钠为主要原料．用干法工艺制备了磷酸酯型两性淀粉：用红外光谱仪（FT-IR）、扫描电子显微镜（SEM）、布拉班德黏度仪和偏光显微镜对产物结构性能进行表征：研究了其作为纸张增强剂对纸浆的增强作用。试验结果表明,制备两性淀粉的最佳工艺是：多聚磷酸钠（STP）添加量为w（STP）=6％;反应pH=6．0;反应温度为145℃;反应时间为1．5h;磷酸酯型两性淀粉对纸张的耐破度、抗张指数和裂断长分别提高了38．2％、24．9％和25．0％,其性能与国民淀粉的两性淀粉接近。     

Effects of hot boning and moisture enhancement on the eating quality of cull cow beef

The effects of chilling method and moisture enhancement were examined for improving eating quality of semimembranosus (SM) and longissimus lumborum (LL) from 62 cull beef cows. Chilling method included hot boning muscles after 45 to 60 min postmortem or conventional chilling for 24 h. Moisture enhancement included 1) a non-injected control (CONT) or injection processing (10% of product weight) using 2) Sodium Tripolyphosphate/salt (Na/STP), 3) Sodium Citrate (NaCIT), 4) Calcium Ascorbate (CaASC), or 5) Citrus Juices (CITRUS). Chilling method by moisture enhancement treatment interactions (P < 0.09) were due to decreased hue, chroma and sarcomere length values in hot boned vs. conventionally chilled product (SM and LL) for CaASC vs. other moisture enhancement treatments. Chilling method by moisture enhancement treatment interactions (P < 0.05) were due to decreased shear force and increased tenderness in conventionally chilled vs. hot boned LL using CaASC vs. Na/STP. Moisture enhancement can improve tenderness of cull cow beef depending on combinations of chilling method and moisture enhancement treatments used.     

大豆分离蛋白的磷酸化改性及功能性质的研究

采用三聚磷酸钠 (STP)对大豆分离蛋白 (SPI)进行化学改性 ,运用三因素二次饱和试验设计 ,得出最优试验回归方程为 :Y =2 8 2 6+5 89X1+0 93X2 +0 83X3-0 1 5 7X12 -1 2 6X2 2 +2 2 6X32 +0 65X1X2 -0 1 5X1X3+0 3 8X2 X3。并得出 6%大豆分离蛋白磷酸化程度最大的工艺条件是 pH 8 0 ,STP浓度为 3 %,45℃下反应 4h。同时研究了改性前后不同程度下SPI的功能性的变化 ,结果表明 ,改性后的SPI的溶解性、乳化能力、持水能力以及粘度等均有很大的提高 ,而发泡性无明显改善。通过红外光谱检测证明 ,STP与SPI反应是赖氨酸残基所进行的磷酸酯化反应。     

双核心校园网设计方案的研究

校园网建设是一个系统工程,目前许多校园网设计方案层出不穷,每个方案都各有特点,但普遍存在网络使用效率低、可靠性和可扩展性差等问题。针对这些问题,关键是要从实际出发,选择适合自己的方案。以校园网设计为例分析以下几个方面：用户需求分析、整体设计方案、系统测试方法以及对可靠性和可扩展性相应的解决办法。