16MnR钢高压除氧器焊接接头裂纹的成因

本文采用电镜，Ｘ射线衍射分析、裂纹扩展速率ｄａ／ｄＮ及门槛值△Ｋｔｈ试验，研究了火力发电厂１６ＭｎＲ钢高压除氧器焊接接头裂纹的形成原因，结果表明，原发裂纹为延迟裂纹，运行工况下，裂纹以应力腐蚀裂纹方式扩展。     

利用零序电流倍增特征的不接地系统故障选线

针对中性点不接地系统单相接地故障选线困难的问题,通过母线故障相接地故障转移与中性点接入小电阻的方式来增强故障信息从而选出故障线路。建立了故障转移阶段、并联电阻投入前后各个阶段的零序网络模型,分析了健全线路和故障线路各自的零序电流幅值的变化特征。在中性点小电阻投入、母线开关分闸前后各馈线零序电流幅值变化明显,健全线路零序电流在母线开关分闸后显著减小而故障线路零序电流增大。利用故障线路与健全线路的零序电流变化特征构建了不接地系统故障选线判据。大量的仿真计算验证了该方法对于不接地系统单相接地故障良好的适应性,有助于进一步提高故障选线准确率。     

Boosting the Microbial Electrosynthesis of Acetate from CO2 by Hydrogen Evolution Catalysts of Pt Nanoparticles/rGO

Catalysis Letters - Microbial electrosynthesis (MES) is an effective approach to driving the CO2 reduction to multi-carbon organic products using renewable energy. In this work, the MES of acetate...     

基于粒子群优化算法的配电网故障指示器优化配置

近年来,故障指示器凭借其接入灵活性和经济性被广泛应用于配电网故障定位中.然而过多的安装是没有必要的,合理选择安装故障指示器的数量及位置能达到配电网可靠性及经济性的综合最优.针对配电网中故障指示器优化配置问题,提出了一个综合考虑配电网可靠性指标及经济性的目标函数,并运用二进制粒子群优化算法进行了优化求解.通过在IEEE 33节点配电系统中的测试,验证了所建模型的有效性.同时,与免疫算法的优化结果进行了对比,分析结果表明,二进制粒子群算法由于其收敛速度快,所需迭代次数少,对于求解该问题具有优势.     

Local Epidermal Endocrine Estrogen Protects Human Melanocytes against Oxidative Stress,a Novel Insight into Vitiligo Pathology

As the outermost barrier of the body, skin is a major target of oxidative stress. In the brain, estrogen has been reported synthesized locally and protects neurons from oxidative stress. Here, we explored whether estrogen is also locally synthesized in the skin to protect from oxidative stress and whether aberrant local estrogen synthesis is involved in skin disorders. Enzymes and estrogen receptor expression in skin cells were examined first by quantitative real-time PCR and Western blot analyses. Interestingly, the estrogen synthesis enzyme was mainly localized in epidermal keratinocytes and estrogen receptors were mainly expressed in melanocytes among 13 kinds of cultured human skin cells. The most abundant estrogen synthesis enzyme expressed in the epidermis was 17β-hydroxysteroid dehydrogenase 1 (HSD17β1) localized in keratinocytes, and the most dominant estrogen receptor expressed in the epidermis was G protein-coupled estrogen receptor 1 (GPER1) in melanocytes. To investigate whether keratinocyte-derived estradiol could protect melanocytes from oxidative stress, cultured human primary epidermal melanocytes (HEMn-MPs) were treated with H₂O₂ in the presence or absence of 17β estradiol or co-cultured with HSD17β1 siRNA-transfected keratinocytes. Keratinocyte-derived estradiol exhibited protective effects against H₂O₂-induced cell death. Further, reduced expression of HSD17β1 in the epidermis of skin from vitiligo patients was observed compared to the skin from healthy donors or in the normal portions of the skin in vitiligo patients. Our results suggest a possible new target for interventions that may be used in combination with current therapies for patients with vitiligo.     

Cytological Observations and Bulked-Segregant Analysis Coupled Global Genome Sequencing Reveal Two Genes Associated with Pollen Fertility in Tetraploid Rice

Neo-tetraploid rice with high fertility is a useful germplasm for polyploid rice breeding, which was developed from the crossing of different autotetraploid rice lines. However, little information is available on the molecular mechanism underlying the fertility of neo-tetraploid rice. Here, two contrasting populations of tetraploid rice, including one with high fertility (hereafter referred to as JG) and another with low fertility (hereafter referred to as JD), were generated by crossing Huaduo 3 (H3), a high fertility neo-tetraploid rice that was developed by crossing Jackson-4x with 96025-4x, and Huajingxian74-4x (T452), a low fertility autotetraploid rice parent. Cytological, global genome sequencing-based bulked-segregant (BSA-seq) and CRISPR/Cas9 technology were employed to study the genes associated with pollen fertility in neo-tetraploid rice. The embryo sacs of JG and JD lines were normal; however, pollen fertility was low in JD, which led to scarce fertilization and low seed setting. Cytological observations displayed low pollen fertility (25.1%) and approximately 31.3 and 27.2% chromosome lagging at metaphase I and II, and 28.8 and 24.8% chromosome straggling at anaphase I and II in JD, respectively. BSA-seq of F_2–3 generations and RNA-seq of F₄ generation detected a common fragment, i.e., 18,915,234–19,500,000, at chromosome 7, which was comprised of 78 genes associated with fertility. Among 78 genes, 9 genes had been known to be involved in meiosis and pollen development. Two mutants ny1 (LOC_Os07g32406) and ny2 (LOC_Os07g32040) were generated by CRISPR/Cas9 knockout in neo-tetraploid rice, and which exhibited low pollen fertility and abnormal chromosome behavior. Our study revealed that two unknown genes, LOC_Os07g32406 (NY1) and LOC_Os07g32040 (NY2) play an important role in pollen development of neo-tetraploid rice and provides a new perspective about the genetic mechanisms of fertility in polyploid rice.     

X射线衍射-拉伸法测薄膜应力

薄膜应力的测量一直是一个困难的问题。本文尝试用一种新的方法——X射线衍射-拉伸法,对薄膜的应力进行检测,与侧倾法实验结果相比较,X射线衍射-拉伸法更为准确与可靠。     

定向凝固的进展对高纯铝偏析法提纯工艺的影响

铝提纯工艺为高纯铝发展的关键。现在国内外通用的高纯铝制备工艺为三层液电解法和分步冷凝法。由于能耗高或提纯效率低，这两种工艺都不能完全满足当今工业发展的需要。针对当前广泛采用的凝固偏析法，结合定向凝固的新进展，讨论了改进结晶方式，提高提纯效率和生产效率的工艺方法。     

基于时序特征的发电机转子故障诊断方法

提出了一种利用时序特征进行发电机转子的故障诊断方法.利用时间序列法中的AR或ARMA模型得到的脉冲传递函数的特点,并根据不同故障类别振动信号的格林函数变化的规律性,提出了利用格林函数的统计量特征作为故障诊断的特征参数进行故障诊断的方法.     

基于Windows的液压实时测试浅析

本文通过分析WINDOWS实时处理的局限性，提出了解决问题的几种机制；同时以液压元件的实时测试中断程序的实现为例说明了机制的应用，研究表明，这种机制较传统方法实用、有效。