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Search Results: 1 - 10 of 107171 matches for " 汪仪林 "
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广义谱相关子空间拟合DOA估计原理
金梁,殷勤业,
电子学报 , 2000,
Abstract: 本文提出了一种用广义谱相关信号子空间拟合进行波达方向估计的方法,该方法同时适用于宽带与窄带信号的DOA估计,在窄带情形下还能够大大提高阵列的等效孔径.理论分析表明,目前几种主要的循环平稳DOA估计方法(如SC-SSF,CyclicMUSIC,CyclicESPRIT)均可看作是该方法的特例或近似.最后,仿真结果证明了该方法的有效性与一般性.
CONJUGATE CYCLIC ESPRIT ALGORITHM BY EXPLOITATION OF MINIMUM-REDUNDANCY LINEAR-ARRAYS
基于最小冗余线阵的共轭循环ESPRIT算法

Yao Minli,Yan Qinye,Wang Yilin,
姚敏立
,殷勤业,

电子与信息学报 , 1999,
Abstract: In this paper, conjugate cyclic ESPRIT with minimum-redundancy linear-arrays is presented. Theoretical analysis and computer simulation show that the algorithm has better performance, such as extending aperture, being insensitive to noise, having higher resolution, and estimating more sources with fewer sensors. Computer simulation results and comparisons with conjugate cyclic ESPRIT are presented to demonstrate the performance of the proposed algorithm.
江苏中部粉砂淤泥质滩岸大剖面所揭示的滩岸发育过程与环境演变
王建,沙润,永进,萧家,周春,胡晓晓,陈国祥,黄夕川
沉积学报 , 1997,
Abstract: 通过对39个钻孔组成的长约10km的江苏中部粉砂淤泥质滩岸大剖面地层与沉积物的多项指标分析发现,江苏大丰一带现代潮滩及潮下带的位置上,40~20KaBp之间曾为潮滩环境,20~10Ka沉积间断、地层缺失,10Ka以来曾一度发育古潮流沙脊群,现代潮滩仅仅是近几百年来在潮流沙脊群之上发育而成的。
介绍一种蜡封矿石小体重(视比重)测定的方法

地质与勘探 , 1964,
Abstract: 本法是依据虹吸作用,在测定时,把蜡封矿石直接放在一个自由表面不大的盛有水的容器中,矿石所排开的等体积水即通过虹吸管全部转入另一个精确的量器.这时,从量器壁上的刻度读出该蜡封矿石的体积.此方法操作简便,容易掌握,而且避免了很多繁杂的加减数字,质量也能满足要求.因该方法与水的密度无关,所以测定时可不考虑用水类型.
飞机座舱透明件的环境设计与选材——两种透明塑料使用性能问题讨论

材料工程 , 1988,
Abstract: 本文分析了共聚的YB-4耐热有机玻璃和不增塑的聚乙烯醇缩丁醛胶片(813中间膜)的物理、化学特性,从实际使用条件的角度讨论了两种透明塑料用作飞机座舱有机玻璃透明件和前风挡玻璃中间层材料选材的合理性。
油茶对高脂饮食引起大鼠肝损伤的保护作用

- , 2017, DOI: 10.13982/j.mfst.1673-9078.2017.1.003
Abstract: 本文主要研究了油茶对高脂饮食引起的大鼠肝损伤的保护作用。试验中将大鼠分为空白对照组、高脂模型组、油茶低、中和高剂量组,每组10只。经造模期15 d和给样期32 d后,腹主动脉采血,取肝脏。测定大鼠肝脏重量,观察肝脏组织病理;分别测定血清中ALT和AST活力,血清和肝匀浆中SOD、GSH-Px活力和MDA水平。结果表明,与高脂模型组相比,油茶组肝脏系数显著降低(p<0.05);血清中ALT和AST活力显著降低(p<0.05);血清和肝脏中SOD和GSH-Px活力显著升高,MDA含量显著降低(p<0.05);肝脏组织病理显示,油茶组能够减轻肝细胞脂肪变性。由结果可知:油茶能够缓解高脂饮食大鼠肝脏肥大,增强机体抗脂质过氧化能力,缓解肝脏脂肪变性,对肝脏损伤起到有效的保护作用,其中油茶高剂量组作用最明显。
This study aimed to investigate whether oil tea (OT) could protect against hepatic damage induced by a high-fat diet (HFD) in rats. In this experiment, 50 rats were randomly divided into five groups, including the untreated control group, HFD control group, and low, medium, and high-dose OT groups, with 10 rats in each group. After the HFD-modeling period of 15 days and OT administration of 32 d, blood samples were collected from the abdominal aorta, and livers were harvested simultaneously. Liver weights were recorded and histopathologic slides were prepared and observed. The activities of alanine transaminase (ALT) and aspartate transaminase (AST) in serum, and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels in the serum and liver were measured. The results showed that compared with the HFD control group, the liver index of OT groups was significantly decreased(p < 0.05), ALT and AST activities in serum were significantly reduced (p<0.05), SOD and GSH-Px activities in the serum and liver were significantly increased, and the level of MDA was significantly lowered (p<0.05). Hepatic histopathology indicated that OT could relieve hepatic steatosis in rats. These results demonstrate that OT can alleviate hepatic hypertrophy, enhance the body’s anti-lipid peroxidation ability, relieve fatty degeneration of liver, and exert a protective effect on hepatic damage in HFD rats. In addition, the most effective group was the high-dose OT group.
82例青年维生素A营养状况的调查及补充效果观察
晓明,
中国公共卫生 , 1994,
Abstract: ?用高效液相色谱法测定北京82例健康青年血清维生素A水平,并记录其膳食维生素A与胡萝卜素摄入情况。结果表明,受检者膳食维生素A与胡萝卜素平均每日摄入量为279.1±120.4μg视黄醇当量,与推荐的每日膳食供给量比较普遍摄入不足。血清维生素A平均含量为1.33±0.42μmol?L,其中14.6%受检者血清维生素A含量低于正常水平。对血清维生素A含量较低的志愿者口服补充维生素A胶九每人合计32.02万Iu后,血清维生素A显著提高。
so2水合物诱发蚕豆(viciafaba)根尖细胞染色体畸变效应
慧兰?,
生态学报 , 2007,
Abstract: 以蚕豆为材料,研究so2水合物-亚硫酸钠与亚硫酸氢钠混合液(3∶1,?mmol?l-1/?mmol?l-1)对根尖细胞的遗传毒效应。结果表明:so2水合物处理可诱发蚕豆根尖细胞遗传不稳定,出现染色体数目和结构变异,使非整倍体和染色体结构异常明显增加。中期染色体出现了缺失、断片、环(染色体和染色单体环)、易位、双着丝粒等异常;在细胞分裂后期出现了滞后染色体、桥和断片等异常。研究结果表明,so2是dna分子断裂剂、非整倍体诱变剂,能够破坏生物细胞的基因组稳定性,是一种具有遗传毒性的环境诱变剂。
津血源增加口干症模型鼠唾液分泌机制的实验研究
刘燕,,钱先
中国中药杂志 , 2014,
Abstract: 为分析津血源的具体作用机制,该实验对津血源增加口干症模型SD大鼠唾液分泌与激动受体之间的关系进行了研究。研究通过使用M受体阻滞剂4-二苯乙酰氧基-N-甲基-哌啶(4-DAMP)和阿托品,或肾上腺受体阻滞剂酚妥拉明,制作3组口干症模型大鼠;造模成功后,予中药津血源灌胃,根据临床常用剂量及SD大鼠体表面积换算,阿托品组将实验动物分为津血源低、中、高剂量组,4-DAMP及酚妥拉明组灌胃中剂量津血源。所有动物给药后,连续测定150min的唾液分泌量,观察津血源增加唾液分泌的作用特点及与受体之间的关系;并分离大鼠的颌下腺组织,通过Westernblot分析津血源对颌下腺细胞水分子通道蛋白5(AQP5)表达的影响。结果发现,比较各组唾液分泌量,与生理盐水组、酚妥拉明组、4-DAMP组及阿托品组相比,津血源组的唾液分泌明显增加,并存在明显差异,P<0.05。在阿托品组中,津血源低剂量组与生理盐水组疗效相当,而津血源中剂量组与生理盐水组相比,存在统计学差异(P<0.05)。唾液分泌量增加的时间曲线图中,发现津血源组与生理盐水组之间存在统计学差异(P<0.05)。与各阻断剂组相比,津血源治疗组颌下腺细胞AQP5蛋白量的表达较前增加,P<0.05;除阿托品组外,津血源对其余2组阻断剂的疗效与生理盐水组无明显差异。对津血源给药后的3种阻断剂AQP5的表达量进行比较,发现津血源对阿托品组的疗效比4-DAMP、酚妥拉明组更明显(P<0.05),后两者之间并不存在统计学差异。因此,研究认为津血源增加唾液分泌(养阴生津作用)的机制可能是通过毒蕈碱M受体(尤其是M3受体)、肾上腺素受体介导的作用途径,增加唾液腺细胞膜AQP5的表达,促进唾液分泌。
中枢胆碱能系统与癫痫关系的研究进展
王颖(),,陈忠()
- , 2017, DOI: 10.3785/j.issn.1008-9292.2017.02.03
Abstract: 癫痫是一种慢性中枢神经系统疾病,其发生不仅与“兴奋性谷氨酸能神经元和抑制性γ-氨基丁酸(γ-GABA)能神经元的失衡”相关,亦与异常的中枢胆碱能神经元调控有着密切联系。本文从细胞分子水平和神经网络水平概括了癫痫发作过程中中枢胆碱能系统的结构功能改变及其在癫痫中可能扮演的角色。在细胞分子水平,多个不同脑区的代谢型毒蕈碱样胆碱能受体异常与多种类型癫痫密切相关,而离子型烟碱样受体突变与一种特定癫痫类型常染色体显性引发的额叶癫痫相关。在神经网络水平,脑内投射型胆碱能神经元及其与其他神经元的交互作用可能参与癫痫发作,尤其基底前脑到海马的胆碱能神经元投射可能与癫痫密切相关,而局部中间型胆碱能神经元暂未发现与癫痫有关。随着光遗传学等技术的发展,发现并解析胆碱能相关的癫痫环路机制并进行调控已成为目前研究的热点。
Abstract: Epilepsy is a chronic neurological disorder, which is not only related to the imbalance between excitatory glutamic neurons and inhibitory GABAergic neurons, but also related to abnormal central cholinergic regulation. This article summarizes the scientific background and experimental data about cholinergic dysfunction in epilepsy from both cellular and network levels, further discusses the exact role of cholinergic system in epilepsy. In the cellular level, several types of epilepsy are believed to be associated with aberrant metabotropic muscarinic receptors in several different brain areas, while the mutations of ionotropic nicotinic receptors have been reported to result in a specific type of epilepsy-autosomal dominant nocturnal frontal lobe epilepsy. In the network level, cholinergic projection neurons as well as their interaction with other neurons may regulate the development of epilepsy, especially the cholinergic circuit from basal forebrain to hippocampus, while cholinergic local interneurons have not been reported to be associated with epilepsy. With the development of optogenetics and other techniques, dissect and regulate cholinergic related epilepsy circuit has become a hotspot of epilepsy research. Key words: Epilepsy/physiopathology Receptors, cholinergic Hippocampus Neurons Review
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