电解液中痕量HF对LiMn2O4电化学性能的影响

使用尖晶石LiMn2O4作为锂离子蓄电池阴极材料,采用恒电流充放电和粉末微电极的循环伏安方法对比研究了电解液中痕量HF对不同电解质溶液体系电化学性能的影响。结果发现, 在1 mol·L-1 LiClO4/(EC DMC)(体积比为1∶1)电解液中,痕量HF对尖晶石LiMn2O4正极材料的电化学嵌脱锂性能有一定的改善和提高。这是因为在1 mol·L-1 LiClO4/(EC DMC)电解液中,HF与LiClO4间特殊的相互作用有利于电极界面在首次充电过程中建立有效的固体电解质相界面(SEI)膜,从而改善了电极材料的结构稳定性,提高了电极电化学性能。但HF添加量过大时,电极/电解液相界面形成的SEI膜太厚,导致电极与电解液间的高界面电阻,反而造成尖晶石LiMn2O4电化学性能下降。     

Li/FeS2电池放电性能的研究

对Li/FeS2电池进行了研制,得到了生产工艺和技术参数.研究了改善Li/FeS2电池放电性能的两种方法:一是在正极中加入活性物质添加剂;二是增加电解液中无机盐成分.结果表明:在正极中加入金属单质和氧化物以及增加电解液中无机盐含量,Li/FeS2电池的放电容量和放电平台都有显著改善.综合不同放电制度的测试结果,最佳添加剂用量为金属单质0.5%、氧化物3%、无机盐0.4%.     

锂离子电池性能研究现状与进展

综述了锂离子电池在比能量、工作特性以及环境适应能力等方面的研究进展。讨论了改进锂离子电池性能的方法。采用具有较高贮锂能力的负极材料、对正极材料进行掺杂和表面修饰等方法都有利于改善电池的电化学性能。电解液添加剂改善了碳负极SEI膜的性能,提高了电池的安全性能。     

限流用BaTiO3系PTC陶瓷的制备及影响因素

介绍了以钛酸四丁酯和自制高纯醋酸钡为主要原料,采用溶胶–凝胶一步法(sol-gel)制备限流用BaTiO3系PTC陶瓷材料的工艺路线,用正交实验法研究了Ti/Ba,Pb,Ca,Y,Mn等组分因素对PTC陶瓷材料性能的影响。优化确定了PTC陶瓷材料的较佳组成。在基方固溶体化学组成,原材料选择和复合添加物的改性,特别是烧结工艺等方面做了细致的工作。最终获得了居里温度(tC)100℃,室温电阻率(r25) ≤20 ·cm,升阻比(Rmax / Rmin)>105,温度系数(aR)≥15% /℃,耐电压(Vb)≥190 V·mm1的PTC陶瓷材料。     

明胶及其改性物作为造纸增强剂的应用

明胶具有优良的性质,作为造纸增强剂很有发展前景。简要介绍了明胶的性质及制备,着重讲述了明胶及其改性物作为造纸增强剂的应用情况,并对其发展作出展望。     

Antioxidant effects of flavonoids used as food additives (purple corn color, enzymatically modified isoquercitrin, and isoquercitrin) on liver carcinogenesis in a rat medium-term bioassay

To clarify the effects of purple corn color, enzymatically modified isoquercitrin (EMIQ), and isoquercitrin (IQ), registered as natural food additives in Japan, on liver carcinogenesis in vivo, a medium-term bioassay was employed. A total of 100 male F344 rats were divided into 5 groups; groups 1 to 4 were given a single intraperitoneal injection of diethylnitrosamine (200 mg/kg b.w.) on day 1. From weeks 2 to 8, they were administered basal diet purple corn color, EMIQ, or IQ as containing test chemicals at doses of 1.0% (groups 1 and 5), 0.1% (group 2), 0.01% (group 3), or 0% (group 4) (experiments 1, 4, and 5). All rats were subjected to two-thirds partial hepatectomy at week 3 and were sacrificed at week 8. Purple corn color exerted no significant modifying effects on GST-P positive foci, preneoplastic foci, development in the liver. However, serum of rats treated with purple corn color provided evidence of antioxidant power significantly by potential antioxidant (PAO) test in vivo (experiment 2). And microarray analyses showed purple corn color to induce RNA expression such as P450 (cytochrome) oxidoreductase, phosphatidylinositol 3-kinase, and phospholipase A2 (experiment 3). Higher doses of EMIQ or IQ with strong antioxidant power in vivo by PAO test treated groups were correlated with smaller numbers of GST-P positive foci, with Spearman's rank correlation coefficients of P= 0.002 and P= 0.049, respectively (experiments 4 and 5). Therefore, the tested food additives may be effective as antioxidants in vivo and have chemopreventive potential against liver preneoplastic lesion development.     

锂离子电池用电解液添加剂最新进展

主要总结了锂离子电池用电解液添加剂最新动态,根据功能和作用原理的不同将添加剂分为SEI成膜促进剂、阴极保护剂、防过充添加剂等;举例分析了各自的作用原理和使用效果。     

Chewing gum consumption in the United States among children,adolescents and adults

Data regarding chewing gum consumption habits and attitudes were collected for 963 children and adolescents (aged 6–14) and 3150 adolescents and adults (aged 13 years+) in the United States (U.S.) using a dedicated online food frequency questionnaire. A total of 79.6% of children/adolescents reported using chewing gum in the last 3 months, whereas 61.8% of adolescents/adults chewed gum in the previous 6 months. The mean and 90th percentile of consumption among children/adolescents aged 6–14 were 1.95 and 4.71 g day^?1, equivalent to 0.75 and 1.78 pieces per day, respectively. Stratification by gender and age brackets revealed that the consumption of chewing gum was more heavily reported in boys compared to girls. Among adolescents/adults aged 13 years and older, the mean and 90th percentile of consumption of chewing gum was estimated to be 2.98 and 7.67 g day^?1, or 1.05 and 3.00 pieces per day, respectively. Stratification by gender and by age brackets in this cohort did not reveal any marked patterns although it was noted that there was a decrease in the percent consuming with age (from 87.0 to 34.5%). The most commonly reported chew frequency among all ages was ‘two or three times a week’ (23.7 to 26.8%). The average and high-level estimates reported herein provide up-to-date estimates of chewing gum consumption in the U.S. Comparisons of the calculated intake values with those reported from the National Health and Nutrition Examination Survey dataset suggests that national nutrition surveys may result in an under-reporting of the percent consumers, but similar estimates for the daily intakes in g day^?1.     

北京地区饲料添加剂中蜡样芽胞杆菌的检测及分析

目的分析北京地区饲用酶制剂、微生态制剂和混合型饲料添加剂产品中蜡样芽胞杆菌污染情况。方法本实验方法在GB/T26427-2010《饲料中蜡样芽胞杆菌的检测》基础上进行优化,利用VITEKII Compact 15全自动生化鉴定及药敏分析系统,对生产环节的94批次样品,进行计数检测和生化鉴定分析。结果对94批次样品进行检测分析,46批次检出蜡样芽胞杆菌,检出率为48.94%。其中30批次样品含量102CFU/g,占总样品数31.91%;4.26%的样品中蜡样芽胞杆菌含量103CFU/g,分别为饲料添加剂植酸酶2批次,混合型饲料添加剂复合酶制剂2批次。结论北京地区饲用酶制剂、微生态制剂和混合型饲料添加剂产品,存在不同程度上被蜡样芽胞杆菌污染的情况。其中酶制剂类产品的污染状况最为严重,酶制剂和含有酶制剂成分的混合型饲料添加剂产品中蜡样芽孢杆菌检出率均高于50%。     

高效液相色谱-串联质谱法同时检测饮料中16种添加剂

目的建立高效液相色谱-串联质谱法同时检测饮料中多种添加剂的分析方法。方法称取样品直接加入50%甲醇溶液,涡旋振荡提取5 min后经聚四氟乙烯(polytetrafluoroethylene, PTFE)滤膜过滤,滤液直接上机进行检测。本实验采用Atlantis T3色谱柱(2.1 mm×150 mm, 3μm), 10 mmol/L乙酸铵-乙腈作为流动相体系进行梯度洗脱;在电喷雾离子化(ESI)正负离子扫描模式下,以多重反应监测(multiplereactionmonitoring,MRM)为基础进行检测,通过外标法进行定量分析;最后,考察了不同浓度的溶剂对目标分析物的提取效率及不同规格的滤膜对目标分析物的吸附效应。结果此方法可快速准确检测苯甲酸等16种食品添加剂,浓度范围在0.02～1μg/mL内线性相关良好,相关系数(r)均大于0.995,平均回收率为75.92%～114.13%,相对标准偏差(relative standard deviation, RSD)为0.42%～7.69%(n=6)。结论本方法适用于同时快速检测饮料中的多种添加剂。