煤矿环境中人体ESD模型

在有瓦斯的煤矿环境中,井下工作人员等效于移动的孤立静电导体,人体静电比井下器材静电更具有隐蔽性、偶发性、危险性.本文通过实验确定能代表煤矿特殊环境中的人体电容、人体电阻,建立煤矿环境中的人体ESD物理模型,为制定煤矿人体静电安全标准提供实验依据.     

Zn(Ⅱ)与TγNPNPyP卟啉嵌入反应的动力学研究

以KCl、KBr、KI、KNO3为支持电解质,在pH为1.5～3.0范围内,研究了Zn(Ⅱ)与水溶性的中位-四(4-N-氰乙基吡啶基)卟啉(TγNPNPyP)的反应动力学,利用计算机线性回归拟合,给出了其表观速率常数的一般表达式.研究表明,Zn(Ⅱ)与T γNPNPyP嵌入反应速率顺序为KCl介质＞KBr介质＞KI介质＞KNO3介质,这与Zn(Ⅱ)和Cl-、Br-、I-、NO3-形成配合物的稳定性是一致的,表明平衡阴离子也参与了配位.     

纳米复合技术改善工业ZnO压敏电阻避雷器微观结构及电性能的研究

运用纳米复合技术对工业ZnO压敏电阻避雷器的制备工艺的改进,研制出压敏电压340 V/mm,漏电流小于1μA,非线性系数大于56的压敏电阻器。根据ZnO晶粒生长动力学方程,研究了纳米复合ZnO粉体的烧结过程以及烧结过程中的晶粒生长规律,用扫描电镜和能谱对瓷体显微结构及面扫成分进行了分析,讨论了添加纳米复合粉的ZnO压敏电阻避雷器微观组织与综合性能的关系。实验表明,添加纳米复合粉体是降低大规模生产成本,提高经济效益,并得到综合性能优良产品的有效方法。     

Generating semi-algebraic invariants for non-autonomous polynomial hybrid systems

Hybrid systems are dynamical systems with interacting discrete computation and continuous physical processes, which have become more common, more indispensable, and more complicated in our modern life. Particularly, many of them are safety-critical, and therefore are required to meet a critical safety standard. Invariant generation plays a central role in the verification and synthesis of hybrid systems. In the previous work, the fourth author and his coauthors gave a necessary and sufficient condition for a semi-algebraic set being an invariant of a polynomial autonomous dynamical system, which gave a confirmative answer to the open problem. In addition, based on which a complete algorithm for generating all semi-algebraic invariants of a given polynomial autonomous hybrid system with the given shape was proposed. This paper considers how to extend their work to non-autonomous dynamical and hybrid systems. Non-autonomous dynamical and hybrid systems are with inputs, which are very common in practice; in contrast, autonomous ones are without inputs. Furthermore, the authors present a sound and complete algorithm to verify semi-algebraic invariants for non-autonomous polynomial hybrid systems. Based on which, the authors propose a sound and complete algorithm to generate all invariants with a pre-defined template.     

基于模拟有限差分的嵌入式离散裂缝数学模型

嵌入式离散裂缝模型划分网格时不需要考虑油藏内的裂缝形态,只需对基岩系统进行简单的网格剖分,可以大大降低网格划分的复杂度,从而能够提高计算效率.并且该模型可以将现有成熟的油藏数值模拟技术和离散裂缝网络模型有机地结合起来,能精细地模拟流体在裂缝性油藏中的流动.本文模型求解采用模拟有限差分方法,该方法基于单个网格的节点和面信息构造数值计算格式,理论上适用于任何复杂网格系统,且具有良好的局部守恒性,将其推广到嵌入式离散裂缝模型后,克服了该模型基于有限差分方法求解时不能有效处理全张量形式的渗透率以及不适用于复杂边界形状裂缝性油藏的局限性.最后通过实际算例验证了本文方法的正确性和优越性.     

Mutations in NMNAT1 cause Leber congenital amaurosis and identify a new disease pathway for retinal degeneration

Leber congenital amaurosis (LCA) is a blinding retinal disease that presents within the first year after birth. Using exome sequencing, we identified mutations in the nicotinamide adenine dinucleotide (NAD) synthase gene NMNAT1 encoding nicotinamide mononucleotide adenylyltransferase 1 in eight families with LCA, including the family in which LCA was originally linked to the LCA9 locus. Notably, all individuals with NMNAT1 mutations also have macular colobomas, which are severe degenerative entities of the central retina (fovea) devoid of tissue and photoreceptors. Functional assays of the proteins encoded by the mutant alleles identified in our study showed that the mutations reduce the enzymatic activity of NMNAT1 in NAD biosynthesis and affect protein folding. Of note, recent characterization of the slow Wallerian degeneration (Wld(s)) mouse model, in which prolonged axonal survival after injury is observed, identified NMNAT1 as a neuroprotective protein when ectopically expressed. Our findings identify a new disease mechanism underlying LCA and provide the first link between endogenous NMNAT1 dysfunction and a human nervous system disorder.     

A genome-wide association study in Chinese men identifies three risk loci for non-obstructive azoospermia

Non-obstructive azoospermia (NOA) is one of the most severe forms of male infertility. Its pathophysiology is largely unknown, and few genetic influences have been defined. To identify common variants contributing to NOA in Han Chinese men, we performed a three-stage genome-wide association study of 2,927 individuals with NOA and 5,734 controls. The combined analyses identified significant (P < 5.0 × 10(-8)) associations between NOA risk and common variants near PRMT6 (rs12097821 at 1p13.3: odds ratio (OR) = 1.25, P = 5.7 × 10(-10)), PEX10 (rs2477686 at 1p36.32: OR = 1.39, P = 5.7 × 10(-12)) and SOX5 (rs10842262 at 12p12.1: OR = 1.23, P = 2.3 × 10(-9)). These findings implicate genetic variants at 1p13.3, 1p36.32 and 12p12.1 in the etiology of NOA in Han Chinese men.     

东濮凹陷胡庆地区原油地球化学特征与油源分析

研究东濮凹陷胡庆地区原油地球化学特征及其来源.利用有机地球化学分析方法,对原油与烃源岩进行饱和烃色谱、饱和烃与芳烃色谱-质谱分析,剖析了两者的分子地球化学特征及油源.研究表明:胡庆地区发育3类原油,第一类原油具有极高伽马蜡烷,质量色谱图中甾烷呈"L"形特征,来自第二台阶的沙一段烃源岩,在沙一段储层中富集形成自生自储常温...     

乌骨藤化学成分和生物活性研究进展

综述了近年来乌骨藤化学成分和生物活性研究方面的进展,主要包括化学成分、生物活性、临床应用概述,并对它的研究和应用前景作了展望。     

复空间形式的紧致全实伪脐子流形

主要研究复空间形式中具有平行法平均曲率向量的紧致全实伪脐子流形,给出了截面曲率作为全脐子流形判定条件的结果.