微型高频脉冲管制冷机的实用化

高频微型脉冲管制冷机在许多领域具有重要作用,目前从原理样机到实用化的成品机仍有一些问题须要解决。介绍在一台达到世界先进水平的高效同轴脉冲管制冷机的基础上进行实用化的工程样机研究,并通过模拟计算分析两台脉冲管制冷机工程样机与原理样机的区别及其自身特点,为进一步开展工作奠定了基础。制作的两台工程样机基本达到了原理样机的制冷性能,不锈钢结构的工程样机外观精美、结构紧凑,但由于材料和外形的原因,制冷性能稍逊于原理样机;铜壁结构的工程样机性能优于不锈钢样机,足以满足工程项目的需要,但重量有所增加。     

严重事故下吸湿性气溶胶的自然去除研究

反应堆发生严重事故时,堆芯释放出的吸湿性气溶胶会在潮湿的安全壳内增大,从而影响其自然去除过程。本文理论推导了吸湿性气溶胶的增大模型并通过多种方法对其进行了验证。模型计算结果表明,气溶胶的增大过程由于受到溶解度的限制而存在临界湿度值,在该临界值以下时气溶胶不发生吸湿,但这未被其他严重事故分析程序所考虑。同时,基于某三代先进压水堆的特定严重事故工况,本文分析了干颗粒半径及湿度对气溶胶的平衡半径和自然去除系数的影响。结果表明:气溶胶的自然去除系数随干颗粒半径的增大将先减小后增加,并在1μm时达到最小值;相同湿度下,干颗粒半径对气溶胶半径的最大增大比例的影响不大;湿度的增加对不同干颗粒半径气溶胶去除系数的影响不同。     

核设备抗震鉴定试验中功率谱密度检验方法分析评估

为满足核设备抗震鉴定试验中输入运动的功率谱密度(PSD)要求,基于对规范背景和目标PSD算法的调研以及典型算例的对比分析,对PSD的检验方法进行分析评估。结果表明,检验PSD最为直观的方法即对比输入运动PSD与目标PSD;根据各类目标PSD算法的结果精度、保守性及其规范依据,推荐使用2014版美国核管理委员会标准审查大纲(SRP)3.7.1节附录B中人工合成时程的方式来计算目标PSD:虽然该算法通常适用于核电厂的厂址设计反应谱,但对于设备抗震鉴定反应谱,仅需将人工合成时程的目标反应谱替换为鉴定反应谱即可;采用本文推荐方法计算目标PSD时,设备抗震鉴定输入运动的PSD检验应与SRP 3.7.1保持一致,即在0.3 Hz到目标反应谱的最高截断频率范围内包络目标PSD的70%。     

基于模糊PID控制的循环水自动加药与监测系统

工业生产中加强对循环水质的处理变得越来越重要,在对循环水系统存在问题进行分析后,利用西门子S7-200 PLC和WinCC组态软件开发设计了新型工业循环水水质在线监测与自动加药系统,解决了传统控制难以保证加药量准确与均匀的问题;针对加酸中pH值过程具有非线性、时变和大时滞等特点,采用了以控制人员的经验为基础的模糊控制方法,结果表明pH值控制误差完全满足系统要求;系统已在化工厂中投入运行,经实践证明,该系统人机交互性好、可靠性高、抗干扰能力强,满足了现代工业循环水质监管的要求。     

现代气压沉箱施工的环境监测及分析

现代气压沉箱施工多应用于大城市繁华地段,为把其对周边环境的影响降到最小,试点工程对气压沉箱施工进行了环境监测方案,并对监测结果进行了分析。监测结果表明:现代气压沉箱施工对周边环境的影响较小,周边土体、邻近建筑物以及地管线的变位能够控制在允许范围之内。     

稠油掺稀井系统效率评价方法研究及应用

针对稠油掺稀井系统效率低问题,通过分析2012年石油行业标准《SY/T5264-2012油田生产系统能耗测试和计算方法》,发现不适应稠油掺稀井系统效率评价因素主要有两方面,一是没有考虑油套环空与油管内流体密度差,二是没有考虑流体黏度摩阻损失,低估了有效举升扬程,造成稠油掺稀井系统效率评价偏低。在原有计算方法基础上引入密度差及黏度摩阻2个参数,制订了适合稠油掺稀井系统效率评价方法。通过将6口稠油掺稀井分别采用《SY/T5264-2012油田生产系统能耗测试和计算方法》和稠油掺稀井系统效率评价方法进行分析,发现后者较前者系统效率平均提升10.7%,提高了稠油掺稀井系统效率,指导油田节能降耗。     

东紫苏(Elsholtiza bodinieri Vaniot)总黄酮的提取及其抗氧化、免疫活性的研究

采用正交实验筛选东紫苏总黄酮的提取工艺;利用清除超氧阴离子自由基（O₂^-·）和清除双氧水（H₂O₂）实验,考察东紫苏总黄酮的抗氧化活性;通过小鼠体内碳粒廓清实验,评价东紫苏总黄酮的免疫活性。结果显示,东紫苏总黄酮的最佳提取工艺为:料液比1∶20（g/m L）、提取温度60℃、回流时间3 h;在50²00μg/m L的浓度范围内,东紫苏总黄酮对O₂^-·和H₂O₂的清除率分别为26.36%⁷3.94%和48.56%⁷7.39%,半数抑制浓度IC₅₀分别为108.07μg/m L和50.59μg/m L;中剂量和高剂量组可显著提高小鼠碳粒廓清指数K和吞噬指数α。表明东紫苏总黄酮具有良好的抗氧化和免疫活性。      

我国国家标准和行业标准中黄曲霉毒素测定方法综述

黄曲霉毒素广泛存在于自然界中,能够污染多种农作物和食品,对人类的健康造成极其严重的危害。目前,尚无绝对有效的措施避免黄曲霉毒素的污染,因此,制定相应的标准并进一步规范和加强对黄曲霉毒素的检测和监控显得尤为重要。截至到2015年1月,我国现行的针对黄曲霉毒素的国家标准和行业标准共有21个,其中有11个标准在2010~2015年发布实施。本文全面综述了21个标准中采纳的7种测定方法及其特点,其中高效液相色谱法是目前广泛使用的最权威的确证定量测定方法,而免疫层析法则是最简便的快速筛查定性检测方法。在此基础上,本文进一步讨论了标准的制修订现状,并展望了黄曲霉毒素检测技术的发展趋势。      

Autophagy: A Double-Edged Sword in Male Reproduction

Autophagy, an evolutionarily conserved cell reprogramming mechanism, exists in all eukaryotic organisms. It is a fundamental and vital degradation/recycling pathway that removes undesirable components, such as cytoplasmic organelles, misfolded proteins, viruses, and intracellular bacteria, to provide energy and essential materials for organisms. The success of male reproduction depends on healthy testes, which are mainly composed of seminiferous tubules and mesenchyme. Seminiferous tubules are composed of Sertoli cells (SCs) and various germ cells, and the main functional part of mesenchyme are Leydig cells (LCs). In recent years, a large amount of evidence has confirmed that autophagy is active in many cellular events associated with the testes. Autophagy is not only important for testicular spermatogenesis, but is also an essential regulatory mechanism for the ectoplasmic specialization (ES) integrity of SCs, as well as for the normal function of the blood–testes barrier (BTB). At the same time, it is active in LCs and is crucial for steroid production and for maintaining testosterone levels. In this review, we expanded upon the narration regarding the composition of the testes; summarized the regulation and molecular mechanism of autophagy in SCs, germ cells, and LCs; and concluded the roles of autophagy in the process of spermatogenesis and testicular endocrinology. Through integrating the latest summaries and advances, we discuss how the role of autophagy is a double-edged sword in the testes and may provide insight for future studies and explorations on autophagy in male reproduction.     

Genetic Dissection of Phosphorus Use Efficiency and Genotype-by-Environment Interaction in Maize

Genotype-by-environment interaction (G-by-E) is a common but potentially problematic phenomenon in plant breeding. In this study, we investigated the genotypic performance and two measures of plasticity on a phenotypic and genetic level by assessing 234 maize doubled haploid lines from six populations for 15 traits in seven macro-environments with a focus on varying soil phosphorus levels. It was found intergenic regions contributed the most to the variation of phenotypic linear plasticity. For 15 traits, 124 and 31 quantitative trait loci (QTL) were identified for genotypic performance and phenotypic plasticity, respectively. Further, some genes associated with phosphorus use efficiency, such as Zm00001eb117170, Zm00001eb258520, and Zm00001eb265410, encode small ubiquitin-like modifier E3 ligase were identified. By significantly testing the main effect and G-by-E effect, 38 main QTL and 17 interaction QTL were identified, respectively, in which MQTL38 contained the gene Zm00001eb374120, and its effect was related to phosphorus concentration in the soil, the lower the concentration, the greater the effect. Differences in the size and sign of the QTL effect in multiple environments could account for G-by-E. At last, the superiority of G-by-E in genomic selection was observed. In summary, our findings will provide theoretical guidance for breeding P-efficient and broadly adaptable varieties.