西藏青稞碳、氢、氧、氮同位素在不同生态域中差异性研究

目的研究青稞中稳定同位素在不同生态域的差异性。方法 2016年在西藏不同生态域种植不同基因型的青稞品种,利用同位素质谱仪测定不同生态域的青稞样品的稳定碳、氢、氧、氮同位素,结合Kolmogorov-Smirnov和Levene统计量分别检验所有数据的正态性和方差同质性,满足方差齐性时采用LSD多重比较,不满足方差齐性时采用Games-Howell多重比较法进行分析,解析不同生态域青稞样品中稳定碳、氢、氧、氮同位素。结果不同区域种植的青稞δ~(13)C值、δ~(15)N值、δ~(18)O值和δD值差异均极其显著(P0.01)。结论稳定碳、氢、氧、氮同位素指纹可用于青稞的产地溯源,可以进一步研究青稞中多元素组成特征及其用于青稞产地溯源的可行性。     

西藏4地市糌粑中重金属含量分析与污染评价

通过调查西藏4地市（山南市、日喀则市、林芝市、拉萨市）不同磨制方式生产的糌粑中重金属砷（As）、镉（Cd）、铬（Cr）、铅（Pb）、汞（Hg）含量,并开展污染情况全面分析评价,以提高西藏各地市糌粑的质量安全水平,为加强质量安全监管提供可靠的数据支持。从西藏4地市分别采集不同模式生产的糌粑样品101个,使用电感耦合等离子体质谱法对糌粑样品中5种重金属进行检测分析与质量安全评价。101个糌粑样品中,按照糌粑质量分级标准综合污染指数进行评价,不同磨制方式生产糌粑中应用单因子污染指数、综合污染指数评价结果显示,电磨和水磨糌粑中的重金属As 、Cd 、Cr、Pb、Hg污染等级均属于安全。不同地市生产糌粑中单因子污染指数及综合污染指数评价结果显示,山南市糌粑中的重金属Pb污染等级属基本清洁,As 、Cd 、Cr、Hg污染等级均属安全;日喀则市糌粑中的重金属As污染等级属基本清洁,Cd 、Cr、Pb、Hg污染等级均属安全;林芝市糌粑中的重金属Pb污染等级属基本清洁,As 、Cd 、Cr、Hg污染等级均属安全;拉萨市糌粑中的重金属Pb、As 、Cd 、Cr、Hg污染等级均属安全;根据Nemerow综合污染等级评价4地市中的其他重金属综合污染指数等级均是安全。因此,西藏4地市糌粑中的重金属As 、Cd、Cr、Pb、Hg综合污染指数等级均是安全。     

果实喷施脱落酸对黑虎香葡萄酒品质的影响

黑虎香葡萄属于鲜食、酿酒兼用品种，香气独特、抗逆性强。对转色期黑虎香葡萄果实喷施不同浓度脱落酸（ABA），研究其对葡萄酒品质的影响。结果表明，喷施500 mg/L ABA处理效果最好，显著提高黑虎香葡萄酒酒精度、干浸出物、花色苷和总酚含量，显著降低酸含量（P＜0.05）；显著增加黑虎香葡萄酒萜烯类、醇类和醛酮类等香气物质含量（P＜0.05），含量影响较大的香气成分为乙酸乙酯、乙酸苯乙酯、苯乙醇、壬醇、戊二酮、香叶基丙酮、乙缩醛、香茅醇和香叶醇。     

Metal ions in neuroscience

Metal ions are believed to participate in many neurodegenerative conditions. In excitotoxic cell death there is convincing evidence for the participation of Ca(2+) and Zn(2+) ions although the exact molecular mechanisms by which these metals exert their effects are unclear. Only in one instance has the metal binding site of metalloenzymes been exploited for therapeutic purposes and this is the use of Li(+) in the treatment of bipolar affective disorder. Again the exact molecular target is not clear but is likely to involve a Mg(2+)-dependent enzyme of an intracellular signalling pathway. In Parkinson's disease, the selective loss of dopaminergic neurones in the substantia nigra may be caused by radical-mediated damage and there is good evidence to suggest that Fe(2+) or (3+) is important in promoting formation of radical species. The evidence that free radicals are important in mediating other neurodegenerative conditions is less strong but still substantial enough to suggest that removal of reactive oxygen species or preventing their formation may be a valid approach to therapy.     

基于激光定位与扫描的钢包温场测量方法

钢包是连接炼钢与浇注环节的容器,即将承接炼钢炉的注入钢水的钢包容器内壁温度直接决定了炼钢炉的出钢温度,与企业节能降耗密切相关.钢包在装盛钢水前的热修工位由行车吊装放置,其放置后的绝对位置难以固定,从而导致温场分布无法确定.针对此现状,本文提出了一种激光定位与扫描的钢包温度场测量方法,先利用定位激光确定被测钢包所处的空间坐标,再由主测量平台执行机构带动扫描激光与红外测温传感器扫描钢包内壁面获取钢包内壁各被测点的测距与温度值,根据空间坐标关系,将被测点测距值映射为钢包坐标数值,从而得到钢包内壁各点坐标与温度值,即温场分布.现场实验表明：该方法可实现钢包温场的获取,坐标定位不确定度≤ 3.0mm;温度测量最大误差4.7℃,最小误差0.5℃,平均误差小于3.3℃,达到较高定位与测量精度,为基于温度信息的冶金工艺控制提供重要参数信息.     

润滑油对齿轮疲劳点蚀的影响

润滑油对齿轮的疲劳点蚀寿命有影响,而且影响很大,润滑油选用不当或润滑油质量不高,可使疲劳点蚀寿命降低一半;选用高性能润滑油可使疲劳点蚀寿命提高2～3倍,而高性能润滑油的关键在添加剂的合理复配．通过对鞍钢线材厂使用的国产525油膜轴承油的试验研究,证明国产润滑完全可以替代进口润滑油,不会降低齿轮的疲劳寿命。     

猴头菇保健醋的生产工艺

文章以猴头菌进行液体发酵、酒精发酵和醋酸发酵等,将猴头菌丝体中的有关物质转化成猴头保健醋中的有效成分,并对工艺进行阐述,提出技术要求.     

Non-lithographic SERS substrates: tailoring surface chemistry for Au nanoparticle cluster assembly

Near‐field plasmonic coupling and local field enhancement in metal nanoarchitectures, such as arrangements of nanoparticle clusters, have application in many technologies from medical diagnostics, solar cells, to sensors. Although nanoparticle‐based cluster assemblies have exhibited signal enhancements in surface‐enhanced Raman scattering (SERS) sensors, it is challenging to achieve high reproducibility in SERS response using low‐cost fabrication methods. Here an innovative method is developed for fabricating self‐organized clusters of metal nanoparticles on diblock copolymer thin films as SERS‐active structures. Monodisperse, colloidal gold nanoparticles are attached via a crosslinking reaction on self‐organized chemically functionalized poly(methyl methacrylate) domains on polystyrene‐block‐poly(methyl methacrylate) templates. Thereby nanoparticle clusters with sub‐10‐nanometer interparticle spacing are achieved. Varying the molar concentration of functional chemical groups and crosslinking agent during the assembly process is found to affect the agglomeration of Au nanoparticles into clusters. Samples with a high surface coverage of nanoparticle cluster assemblies yield relative enhancement factors on the order of 10⁹ while simultaneously producing uniform signal enhancements in point‐to‐point measurements across each sample. High enhancement factors are associated with the narrow gap between nanoparticles assembled in clusters in full‐wave electromagnetic simulations. Reusability for small‐molecule detection is also demonstrated. Thus it is shown that the combination of high signal enhancement and reproducibility is achievable using a completely non‐lithographic fabrication process, thereby producing SERS substrates having high performance at low cost.     

磁场形态对等离子弧堆焊层组织性能的影响

在低碳钢表面进行Fe5自熔合金等离子弧堆焊时外加纵向磁场,并改变磁场形态,对不同磁场参数下堆焊试样进行硬度和磨损试验.采用显微电镜和扫描电镜对堆焊层显微组织进行分析,研究磁场形态和参数对堆焊层组织性能的影响规律和作用机理.结果表明,交、直流纵向磁场均可以改善堆焊层的组织性能,由于交流纵向磁场中频率可调,增加了磁场的可控性,对堆焊层组织性能的作用效果比直流纵向磁场更明显.在焊接电流为160A,磁场电流为3A,磁场频率为10Hz时,堆焊层金属性能达到最佳值,此时硬度为68HRC,磨损量为0.0318g.     

The premarital communication roots of marital distress and divorce: The first five years of marriage.

Using data from 210 couples who provided data across the first 5 years of marriage, we examined how premarital communication quality was related to divorce and later distress. The results showed that premarital observed negative and positive communication nearly reached significance as predictors of divorce, while self-reported negative communication was significantly associated with divorce. In terms of marital adjustment, we found that both premarital observed and self-reported negative premarital communication (but not observed positive communication) were associated with lower adjustment during the first 5 years of marriage. The most important questions addressed in this study pertain to how positive and negative dimensions of communication change over time and how these changes are related to being distressed or nondistressed after 5 years of marriage. This is the first study, to our knowledge, to examine the changes in communication over time that are so central to theories of the development of marital distress and for research-based interventions. We found that all couples showed decreases in negative communication over time, but the nondistressed group declined significantly more than the distressed group in negative communication, suggesting they are handling negative emotions better. Implications for future research on the development of relationship distress and for enhancing research-based couples' intervention programs are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)