BFe30-1-1白铜管早期腐蚀失效原因分析

某电厂凝汽器BFe30-1-1白铜管投运后几年内出现较为严重的局部腐蚀和点腐蚀，为此，对材质、水质等诸多因素进行了分析研究，通过宏观、微观检查和电化学试验，认为是微生物及生物粘泥的附着引起了铜管的早期腐蚀失效。     

The Power of the Brown v. Board of Education Decision: Theorizing Threats to Sustainability.

Interviews with African American and White American elders capture the immediate power of the Brown v. Board of Education (1954) decision and the biography of its impact over time. This article reviews the lived experience of the decision and theorizes 3 threats to sustainability that ruthlessly undermined the decision over time: (a) the unacknowledged and enormous sacrifice endured by the African American community in the name of desegregation; b) the violent and relentless resistance to the decision by government officials, educators, and many White community members; and (c) the dramatic shrinkage of the vision of Brown from the dismantling of White supremacy to a technical matter of busing. Implications are drawn for the study of desegregation and for the study of sustainability of social justice more broadly. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Scientific Attack on Brown v. Board of Education, 1954-1964.

Psychologists' work was cited in the Supreme Court case of Brown v. Board of Education (1954). One criticism of the citation was that psychology could be used to overturn the Brown decision and return the country to segregation. A historical examination of such an attempt to overturn Brown in the early 1960s on the basis of new psychological knowledge shows that psychology was not persuasive in the face of the civil rights movement. The failure of segregationists to overturn Brown with psychological experts underscores how psychology is ineluctably bound to the larger society. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

GC-MS分析天然奶味香精的致香成分

利用气相色谱-质谱联用技术对两种天然奶味香精中的致香成分进行了分析鉴定,结合计算机质谱图库,确定两种香精中的主要致香成分为内酯类、中短链脂肪酸、酯类、噻唑类等化合物.两种香精的香气不同,各化合物之间的组成及含量不同,但含量最高的都为δ-癸内酯.利用确定的GC-MS条件对无水奶油的酶解物进行了分析,鉴定了贡献较大的脂肪酸组成及微量物质.     

婴幼儿配方乳粉危害物分子预测及营养组分数据库的组建

根据国家标准GB10767和GB10765所述方法,搜集、整理并测定完善符合中国国家标准的婴幼儿配方乳粉中的营养组分;综合1998年至2019年所有婴幼儿乳粉产品及原料的食品安全事件及相关文献中涉及的内源及外源危害物,结合数据库技术建立婴幼儿配方乳粉营养组分及危害物分子数据库.基于分子指纹和相似性算法建立婴幼儿乳粉中危...     

固相微萃取技术用于牛奶中有机氯类农药残留的检测

建立了固相微萃取(SPME)-气相色谱-串联质谱(GC-MS/MS)同时测定牛奶中16种有机氯类农药残留的方法。对萃取模式、纤维涂层、萃取温度等实验条件进行了优化。用HP-5 MS弹性石英毛细管柱经柱程序升温技术分离,并用质谱检测器检测,外标法计算含量。待测农药的标准加入回收率在80%～110%之间,方法的相对标准偏差(RSD)≤9.6%,各农药组分的检出限为0.003μg/kg～0.15μg/kg。所测样品不含几种有机氯农药残留。本法简便、干扰小、检测效果好,可用于牛奶中有机氯类农药残留的检测。     

响应面优化低糖滇红奶茶的配方

目的 通过响应面法优化低糖滇红奶茶的配方。方法 以滇红茶、全脂奶粉、零卡糖为主要原料,通过单因素分析结合响应面实验设计优化滇红奶茶配方,并分析产品的理化及卫生指标。结果 优化配方为：滇红茶汁50%、全脂奶粉15%、零卡糖10%、乳化剂0.22%、稳定剂0.2%,此时感官评分为87.83。滇红奶茶浅棕色稳定性好、质地均匀、浓稠恰当、细腻滑润无杂质,甜味适中茶香味与奶香香味协调无异味,经测定蛋白质含量(5.99±0.06)%、脂肪含量(3.38±0.02)%、茶多酚含量(320.6±2.25) mg/kg,微生物指标符合国家标准。结论 本研究开发了一种低糖健康的滇红奶茶,为滇红茶的深加工提供一定的实验依据。     

超高效液相色谱串联质谱法测定牛奶中三氮脒残留

目的 本研究旨在结合超高效液相色谱－串联质谱(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)技术,建立简便、快速的样品前处理方法,对牛奶中的痕量三氮脒残留进行检测。方法 用1%乙酸乙腈溶液振荡提取后,在-4℃条件下高速离心,取上清液旋转蒸干后,用10%乙腈水溶液复溶,用超高效液相色谱-串联质谱仪在正离子扫描及多反应监测(multiple reaction monitoring, MRM)模式下分析,外标法定量。结果 牛奶中三氮脒的检出限(limit of detection, LOD)为5 μg/kg,定量限(limit of quantification, LOQ)为15 μg/kg,在20~1000 μg/L浓度范围内线性良好,相关系数(r)为0.9993。将所研究的方法应用于实际牛奶样本中,其加标回收率在81.65%至85.49%之间,日内精密度分别在4.5%~5.5%,日间精密度在5.9%~8.2%之间。结论 本方法采用振荡提取加低温高速离心净化的前处理方法,简单快速,结合UPLC-MS/MS,可实现痕量水平残留的高灵敏度检测,适用于快速、高灵敏检测牛奶及其他动物源性食品中的三氮脒残留。     

Production of Lacto-N-biose I Using Crude Extracts of Bifidobacterial Cells

Lacto-N-biose I (LNB) is supposed to represent the bifidus factor in human milk oligosaccharides, and can be practically produced from sucrose and GlcNAc using four bifidobacterial enzymes, 1,3-β-galactosyl-N-acetylhexosamine phosphorylase, sucrose phosphorylase, UDP-glucose-hexose 1-phosphate uridylyltransferase, and UDP-glucose 4-epimerase, recombinantly produced by Escherichia coli. Here the production of LNB by the same enzymatic method without using genetically modified enzymes to consider the use of LNB for a food ingredient was reported. All four enzymes were produced as the intracellular enzymes of Bifidobacterium strains. The mixture of the crude extracts contained all four enzymes, with other enzymes interfering with the LNB production, namely, phosphoglucomutase, fructose 6-phosphate phosphoketolase, and glycogen phosphorylase. The first two interfering enzymes were selectively inactivated by heat treatment at 47 °C for 1 h in the presence of pancreatin, and glycogen phosphorylase was disabled by hydrolyzing its possible acceptor molecules using glucoamylase. Finally, 91 % of GlcNAc was converted into LNB in the 100-mL reaction mixture containing 300 mM GlcNAc.     

四川某市散装鲜牛乳质量状况调查

对四川某市市场上的散装生鲜牛乳进行随机抽样,对乳样品进行感官检验、理化检验和微生物检验。结果表明：市售散装生鲜牛乳的蛋白质、脂肪、非脂乳固体、密度等指标低于国家标准规定的要求;微生物严重污染;感官质量较差;掺假现象比较严重。