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A generalization of Poisson-Sujatha distribution and its applications to ecology
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作者 Rama Shanker Kamlesh Kumar Shukla 《生物数学学报:英文版》 2019年第2期37-47,共11页
A generalization of Poisson Sujatha distribution(AGPSD),which includes Poisson-Lindley distribution(PLD)and Poisson-Sujatha distribution(PSD)as particular cases,has been proposed and studied.Its moments and moments-ba... A generalization of Poisson Sujatha distribution(AGPSD),which includes Poisson-Lindley distribution(PLD)and Poisson-Sujatha distribution(PSD)as particular cases,has been proposed and studied.Its moments and moments-based measures including coefficient of variation,skewness,kurtosis and index of dispersion have been obtained and their behaviors have been discussed.The estimation of its parameters has been discussed with maximum likelihood estimation.The applications of the proposed distribution has been explained through two examples of count data from ecology and the goodness of fit of the distribution has been compared with Poisson distribution,PLD and PSD. 展开更多
关键词 Sujatha DISTRIBUTION Poisson-Sujatha DISTRIBUTION GENERALIZATION of Sujatha DISTRIBUTION MOMENTS and moments-based measures maximum LIKELIHOOD estimation APPLICATIONS
Reactive power deployment and cost benefit analysis in DNO operated distribution electricity markets with D-STATCOM
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作者 Atma Ram GUPTA Ashwani KUMAR 《能源前沿:英文版》 CSCD 2019年第1期86-98,共13页
The aim of this paper is to analyze unbalanced radial distribution systems(UBRDS)with the distribution static compensator(D-STATCOM).The main objectives of this paper are D-STATCOM allocation in UBRDS with an objectiv... The aim of this paper is to analyze unbalanced radial distribution systems(UBRDS)with the distribution static compensator(D-STATCOM).The main objectives of this paper are D-STATCOM allocation in UBRDS with an objective of providing reactive power support to enhance voltage profile and reduce line losses of the distribution network,determination of optimal D-STATCOM rating subjected to minimization of total cost,and impact of D-STATCOM placement on improving power factor and savings in cost of energy loss.The analysis is conducted on a large industrial load model with light,medium and high loading scenarios.Further,the impact of load growth is also considered for better planning of the power distribution system.The results are obtained on standard 25-bus UBRDS to check the feasibility of the proposed methodology. 展开更多
关键词 unbalanced DISTRIBUTION system D-STATCOM VOLTAGE sensitivity index LOAD models LOAD growth DISTRIBUTION network operator(DNO)
Theoretical analytic model for RESURF AlGaN/GaN HEMTs
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作者 吴浩 段宝兴 +1 位作者 杨珞云 杨银堂 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第2期395-399,共5页
In this paper, we propose a two-dimensional(2D) analytic model for the channel potential and electric field distribution of the RESURF AlGaN/GaN high electron mobility transistors(HEMTs). The model is constructed by t... In this paper, we propose a two-dimensional(2D) analytic model for the channel potential and electric field distribution of the RESURF AlGaN/GaN high electron mobility transistors(HEMTs). The model is constructed by two-dimensional Poisson’s equation with appropriate boundary conditions. In the RESURF AlGaN/GaN HEMTs, we utilize the RESURF effect generated by doped negative charge in the AlGaN layer and introduce new electric field peaks in the device channels,thus, homogenizing the distribution of electric field in channel and improving the breakdown voltage of the device. In order to reveal the influence of doped negative charge on the electric field distribution, we demonstrate in detail the influences of the charge doping density and doping position on the potential and electric field distribution of the RESURF AlGaN/GaN HEMTs with double low density drain(LDD). The validity of the model is verified by comparing the results obtained from the analytical model with the simulation results from the ISE software. This analysis method gives a physical insight into the mechanism of the AlGaN/GaN HEMTs and provides reference to modeling other AlGaN/GaN HEMTs device. 展开更多
关键词 RESURF ALGAN/GAN HEMTS two-dimensional ANALYTIC model potential DISTRIBUTION electric field DISTRIBUTION
南海永兴岛的壁虎,兼记二新记录种
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作者 钱天宇 齐硕 +4 位作者 李丕鹏 陆宇燕 莫燕妮 杨振洲 刘武汉 《四川动物》 北大核心 2019年第2期179-184,共6页
2017年12月对南海永兴岛的爬行动物进行了短期调查,发现3种壁虎科Gekkonidae动物,分别是截趾虎Gehyra mutilata、原尾蜥虎Hemidactylus bowringii和疣尾蜥虎H. frenatus。其中,截趾虎和原尾蜥虎为中国南海岛屿的新记录。
关键词 壁虎 南海 岛屿 形态 分布
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利用种群扩张与稀疏化策略改进NSGA-Ⅱ-DE算法
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作者 蒋永华 许妙忠 成刚 《控制与决策》 EI CSCD 北大核心 2019年第1期55-62,共8页
NSGA-Ⅱ-DE算法是在NSGA-Ⅱ算法的基础上利用DE算法的收敛速度快、鲁棒性高的特性得到的改进算法,该算法提高了原算法的收敛速度,同时也降低了原算法对参数的依赖性.然而,原算法的解群分布性却没有得到提高.鉴于此,提出一种基于种群扩... NSGA-Ⅱ-DE算法是在NSGA-Ⅱ算法的基础上利用DE算法的收敛速度快、鲁棒性高的特性得到的改进算法,该算法提高了原算法的收敛速度,同时也降低了原算法对参数的依赖性.然而,原算法的解群分布性却没有得到提高.鉴于此,提出一种基于种群扩张与稀疏化策略的改进型NSGA-Ⅱ-DE算法.该算法利用种群扩张增加候选解的数量,再利用稀疏化策略从候选解中选出使得整体分布尽可能均匀的最优解.种群扩张通过在进化最后的若干代保留每代中的第一非支配面上的个体来实现.在迭代结束后,对种群进行非支配排序,去除第一非支配面以外的个体,以提高解群质量.进行稀疏化处理,即对扩张后的全部个体按目标向量的某一维度排序,再筛选出相邻间距最接近期望距离的个体,以达到改善解群分布性的目的.仿真实验表明,所提出的算法在改善原算法的解群分布性上表现优异,但算法的时间和空间复杂度较原算法有所增加. 展开更多
关键词 种群扩张 稀疏化 NSGA-Ⅱ-DE 非支配排序 种群规模 分布性
枯水季和丰水季长江口海域生源硫的浓度变化特征及影响因素 预览
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作者 徐锋 刘龙 +2 位作者 刘欣伟 张洪海 杨桂朋 《环境科学研究》 EI CAS CSCD 北大核心 2019年第1期116-125,共10页
为深入研究河口近岸海域DMS(二甲基硫)的生物地球化学过程,于2014年2月(枯水季)和7月(丰水季)对长江口及附近海域表层海水中DMS及其前体物质DMSP(二甲巯基丙酸内盐)的浓度分布及影响因素进行了研究,测定了DMSPd(溶解态DMSP)的降解速率和... 为深入研究河口近岸海域DMS(二甲基硫)的生物地球化学过程,于2014年2月(枯水季)和7月(丰水季)对长江口及附近海域表层海水中DMS及其前体物质DMSP(二甲巯基丙酸内盐)的浓度分布及影响因素进行了研究,测定了DMSPd(溶解态DMSP)的降解速率和DMS的生物生产与微生物消费速率,并估算了DMS的海-气通量.结果表明:①枯水季和丰水季c(DMS)、c(DMSPd)、c(DMSPp)(DMSPp为颗粒态DMSP)的平均值±标准偏差分别为(0.54±0.28)(2.04±1.32)(6.65±5.07)和(3.99±3.70)(5.57±4.72)(14.26±9.17)nmol/L,长江口海域丰水季生源硫化物的浓度明显高于枯水季.②枯水季和丰水季c(DMSPd)与ρ(Chla)均呈弱相关,说明浮游植物在控制长江口海域DMSP的生产分布中发挥重要作用.③枯水季和丰水季c(DMS)/ρ(Chla)的平均值±标准偏差分别为(2.62±3.28)和(4.60±7.49)mmol/g,表明丰水季DMS的高产藻种(甲藻)在浮游植物生物量中所占比例高于枯水季.④枯水季表层海水中DMSPd的降解速率和DMS的生物生产速率分别介于(2.84~30.53)和(0.52~2.19)nmol/(L·d)之间,平均值分别为14.55和1.30nmol/(L·d),表明DMS并不是DMSPd的主要降解产物.⑤枯水季和丰水季DMS的海-气通量平均值±标准偏差分别为(0.36±0.32)和(2.17±2.98)μmol/(m^2·d),而且丰水季的硫排放量明显高于枯水季,这主要与夏季较高的c(DMS)有关.研究显示,长江口海域生源硫化物的浓度变化及分布特征呈明显的季节性差异,河口近岸海域是海洋有机硫排放的重要区域. 展开更多
关键词 DMS(二甲基硫) DMSP(二甲巯基丙酸内盐) 浓度分布 海-气通量 长江口
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河北省页岩分布及页岩气前景 预览
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作者 张新生 于海成 张华 《中国煤炭地质》 2019年第1期59-65,共7页
页岩气作为非常规清洁能源,已正式进入我国能源战略视野。河北省在漫长的地质历史时期,广泛发育6套黑色页岩岩系:中上元古界洪水庄组和下马岭组、古生界石炭二叠系太原组和山西组、新生界古近系孔店组和沙河街组。岩相分别为海相、海陆... 页岩气作为非常规清洁能源,已正式进入我国能源战略视野。河北省在漫长的地质历史时期,广泛发育6套黑色页岩岩系:中上元古界洪水庄组和下马岭组、古生界石炭二叠系太原组和山西组、新生界古近系孔店组和沙河街组。岩相分别为海相、海陆交互相、湖相暗色泥页岩。其中,元古界页岩主要赋存于燕山以北,古生代与新生代页岩主要发育于冀东南。它们不仅具有分布范围广,埋深适中,是页岩气发育有利层位,具有页岩气资源勘探前景,其勘探开发将对于缓解我省能源危机和环境污染具有重要意义。 展开更多
关键词 页岩气 分布 潜力 河北省
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元以来安多藏区部落及其地方政权的形成与分布情况 预览
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作者 叶拉太 《西藏大学学报》 CSSCI 2019年第1期28-37,共10页
元以来是西藏及其周边区域开始纳入中原王朝国家版图的关键时期,也是藏族封建地方部落政权形成和发展的重要时刻。安多藏区作为中原王朝国家和西藏地方间的缓冲区之一,其政制演变和区域发展走向一直影响着西藏腹地的政治方向。安多藏区... 元以来是西藏及其周边区域开始纳入中原王朝国家版图的关键时期,也是藏族封建地方部落政权形成和发展的重要时刻。安多藏区作为中原王朝国家和西藏地方间的缓冲区之一,其政制演变和区域发展走向一直影响着西藏腹地的政治方向。安多藏区的双重“边缘”位置使这一区域处于一种半自然状态的发展模式,地方性封建割据部落政权相继出现,且随着区域性寺院集团的发展而逐渐形成地方政教联盟系统。这些部落政权形成时间不一,历史演变复杂,地域分布较广,有其特殊的政治历史背景和地域发展特色。 展开更多
关键词 安多藏区 部落政权 形成 分布
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鱼类树突状细胞研究进展 预览
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作者 陈孝煊 李思思 +1 位作者 周成翀 吴志新 《水产学报》 CAS CSCD 北大核心 2019年第1期54-61,共8页
树突状细胞(DCs)是目前已知的体内功能最强的抗原递呈细胞,是唯一能够激活初始T淋巴细胞反应的细胞,在先天性免疫、适应性免疫以及维持自身免疫耐受方面具有重要的作用,因此一直是免疫学研究的重要领域。本文简要综述了DCs的类型及其在... 树突状细胞(DCs)是目前已知的体内功能最强的抗原递呈细胞,是唯一能够激活初始T淋巴细胞反应的细胞,在先天性免疫、适应性免疫以及维持自身免疫耐受方面具有重要的作用,因此一直是免疫学研究的重要领域。本文简要综述了DCs的类型及其在动物体内的功能、各类DCs的细胞标记。总结了鱼类DCs的分离、纯化方法和形态学观察方法;现有研究表明,鱼类DCs具有吞噬细菌、刺激T细胞增殖、诱导CD4+T细胞的活化、表达DCs的标记基因、被Toll样受体的配体激活、迁移能力、引起混合淋巴细胞反应等生物学功能;不同鱼类DCs的分子标记并不完全一样;鱼类的头肾、肾、鳃、皮肤、胸腺、脾、肠等均有DCs的分布。目前,对鱼类DCs的研究虽然取得了一定进展,但仍有许多重要问题需要解决:①鱼类DCs目前缺乏明确的细胞标记,加强这方面的研究有助于提高鱼类DCs的分离、体内分布与功能的研究水平;②加强和完善鱼类DCs的分离、培养技术的研究,掌握各种鱼类DCs的分离培养方法;③加强鱼类DCs在抗原递呈中的功能研究,对深入分析鱼类免疫机理,合理设计和应用疫苗,具有重要的理论指导意义。 展开更多
关键词 鱼类 树突状细胞 形态 分布 细胞标记 功能
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Spatial Distribution Characteristics of Nitrogen and Phosphorus in Sediments of Coastal Wetlands
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作者 Huanqiang ZHENG Kun RONG 《亚洲农业研究:英文版》 2019年第1期42-46,共5页
Taking the typical coastal wetlands in the Yellow River Delta as the research object,(i)three parallel strips A1,A2 and A3 were set up along the vertical coastline in the newborn wetland at 60 km south of the Dongwenl... Taking the typical coastal wetlands in the Yellow River Delta as the research object,(i)three parallel strips A1,A2 and A3 were set up along the vertical coastline in the newborn wetland at 60 km south of the Dongwenliu Management Station in the Yellow River Delta Nature Reserve.(ii)Sample plots B(Phragmites communis area),C(Suaeda glauca area),and D(Tamarix chinensis area)were set up near the field ecological station of the coastal wetlands.Through collecting sediment samples and measuring nitrogen and phosphorus contents,the spatial distribution characteristics of nitrogen and phosphorus in sediments of coastal wetlands were studied.Following results were obtained.(i)The concentration of TN in the 0-20 cm surface sediments of the coastal wetlands in the Yellow River Delta was in the range of 130-695 mg/kg,the concentration of TP was in the range of 589-778 mg/kg,and the average content of TN and TP was 372.18 and 660.82 mg/kg respectively.(ii)From the remote coastal area of the Yellow River to the near coastal area,the horizontal distribution of TN in the sediments was different at each level,and the TN content in the surface sediments gradually decreased;the content of TP generally increased.(iii)At the profile level,the content of TN and TP generally showed a trend of decreasing gradually from the surface layer and tending to be stable,and the peak appeared at the outermost layer.(iv)In the sediments under different vegetation cover,TN was more evenly distributed on each profile,and the distribution of TP on each profile was different.TN showed the largest distribution in the 0-20 cm surface sediments in the T.chinensis area,while TP had the largest distribution in the 80-100 cm bottom sediments in the T.chinensis area. 展开更多
关键词 COASTAL WETLAND SEDIMENT NITROGEN PHOSPHORUS Spatial distribution
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Hydrological Simulation Using TRMM and CHIRPS Precipitation Estimates in the Lower Lancang-Mekong River Basin 预览
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作者 LUO Xian WU Wenqi +2 位作者 HE Daming LI Yungang JI Xuan 《中国地理科学:英文版》 SCIE CSCD 2019年第1期13-25,共13页
Satellite-based products with high spatial and temporal resolution provide useful precipitation information for data-sparse or ungauged large-scale watersheds. In the Lower Lancang-Mekong River Basin, rainfall station... Satellite-based products with high spatial and temporal resolution provide useful precipitation information for data-sparse or ungauged large-scale watersheds. In the Lower Lancang-Mekong River Basin, rainfall stations are sparse and unevenly distributed, and the transboundary characteristic makes the collection of precipitation data more difficult, which has restricted hydrological processes simulation. In this study, daily precipitation data from four datasets(gauge observations, inverse distance weighted(IDW) data, Tropical Rainfall Measuring Mission(TRMM) estimates, and Climate Hazards Group InfraRed Precipitation with Stations(CHIRPS) estimates), were applied to drive the Soil and Water Assessment Tool(SWAT) model, and then their capability for hydrological simulation in the Lower Lancang-Mekong River Basin were examined. TRMM and CHIRPS data showed good performances on precipitation estimation in the Lower Lancang-Mekong River Basin, with the better performance for TRMM product. The Nash-Sutcliffe efficiency(NSE) values of gauge, IDW, TRMM, and CHIRPS simulations during the calibration period were 0.87, 0.86, 0.95, and 0.93 for monthly flow, respectively, and those for daily flow were 0.75, 0.77, 0.86, and 0.84, respectively. TRMM and CHIRPS data were superior to rain gauge and IDW data for driving the hydrological model, and TRMM data produced the best simulation performance. Satellite-based precipitation estimates could be suitable data sources when simulating hydrological processes for large data-poor or ungauged watersheds, especially in international river basins for which precipitation observations are difficult to collect. CHIRPS data provide long precipitation time series from 1981 to near present and thus could be used as an alternative precipitation input for hydrological simulation, especially for the period without TRMM data. For satellite-based precipitation products, the differences in the occurrence frequencies and amounts of precipitation with different intensities would affect simulation re 展开更多
关键词 hydrological simulation satellite-based PRECIPITATION ESTIMATES spatial distribution of PRECIPITATION international RIVER the LOWER Lancang-Mekong RIVER Basin
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双连双拱双膜塑料大棚温度场分布及应用 预览
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作者 尹庆珍 宫彬彬 +3 位作者 张天策 郄丽娟 赵付江 韩建会 《中国农学通报》 2019年第4期116-124,共9页
为研究新型双连双拱双膜塑料大棚温度场分布及其保温性能问题,基于2016年3月8—10日的新型双连双拱双膜塑料大棚内外GL820绝缘多通道数据记录仪、中长图彩色无纸记录仪、光电式总辐射传感器V2.0的温度、光照记录数据,应用MATLAB软件进... 为研究新型双连双拱双膜塑料大棚温度场分布及其保温性能问题,基于2016年3月8—10日的新型双连双拱双膜塑料大棚内外GL820绝缘多通道数据记录仪、中长图彩色无纸记录仪、光电式总辐射传感器V2.0的温度、光照记录数据,应用MATLAB软件进行二维温度场的拟合和图像绘制。结果表明:06:01为大棚最低温度,最低气温9日>8日>10日;08:01—12:01为温度上升期;8日、10日12:01—16:01为大棚最高温度,9日14:01—16:01为大棚最高温度;22:01温度8日、10日>9日。阴天的8日或阴~晴的9日09:01先从大棚的下部升温,12:01—16:01大棚上部升温较快,20:01—22:01大棚上部降温较快;晴天的10日9:01先从大棚的上部升温,12:01—16:01是3天的最高温度,18:01从大棚下部开始降温,20:01—22:01大棚上部气温最低。在大棚温度最低时或最高时,大棚顶部最高点对应为大棚温度最低点或最高点。夜间00:01—08:01期间10 cm地温较低,地温8日>9日>10日;10日07:00—08:00地温最低(11.3℃)。棚内、外光照强度差距较大,光照强度10日>8日>9日。双连双拱双膜塑料大棚在2月中旬喜温果菜类可以定植,早于单膜塑料大棚25~30天,在春提早方面优势明显。 展开更多
关键词 双连双拱双膜塑料大棚 温度场 分布 MATLAB软件
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Off-axis electron holography of manganite-based heterojunctions:Interface potential and charge distribution
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作者 令志斌 刘桂菊 +2 位作者 杨成鹏 梁文双 王乙潜 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第4期269-274,共6页
The interfacial electrical potentials and charge distributions of two manganite-based heterojunctions, i.e.,La0.67Ca0.33MnO3/SrTiO3:0.05 wt% Nb(LCMO/STON) and La0.67Ca0.33MnO3/LaMnO3/SrTiO3:0.05 wt% Nb(simplified as L... The interfacial electrical potentials and charge distributions of two manganite-based heterojunctions, i.e.,La0.67Ca0.33MnO3/SrTiO3:0.05 wt% Nb(LCMO/STON) and La0.67Ca0.33MnO3/LaMnO3/SrTiO3:0.05 wt% Nb(simplified as LCMO/LMO/STON), are studied by means of off-axis electron holography in a transmission electron microscope.The influences of buffer layer on the microstructure and magnetic properties of the LCMO films are explored. The results show that when a buffer layer of LaMnO3 is introduced, the tensile strain between the STON substrate and LCMO film reduces, misfit dislocation density decreases near the interfaces of the heterojunctions, and a positive magnetoresistance is observed. For the LCMO/STON junction, positive and negative charges accumulate near the interface between the substrate and the film. For the LCMO/LMO/STON junction, a complex charge distribution takes place across the interface, where notable negative charges accumulate. The difference between the charge distributions near the interface may shed light on the observed generation of positive magnetoresistance in the junction with a buffer layer. 展开更多
关键词 LA0.67CA0.33MNO3 films electron HOLOGRAPHY magnetic properties INTERFACIAL electrical POTENTIAL charge distribution
乘用车电线束设计验证方法 预览
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作者 刘毅 《汽车电器》 2019年第3期56-57,60共3页
介绍乘用车电线束系统设计验证方法。首先介绍电线束系统设计验证的主要方式,详细讲解线束走向验证、配电设计验证、搭铁设计验证、电压降测试等几方面的验证方法。最后结合实例说明设计验证对于线束优化设计的影响.
关键词 电线束系统 设计验证 配电 搭铁
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碳税规制下多目标冷链物流配送路径优化 预览
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作者 陶志文 张智勇 +2 位作者 石艳 张艳伟 石永强 《武汉理工大学学报:信息与管理工程版》 CAS 2019年第1期51-56,共6页
针对碳税规制下的冷链物流配送问题,提出一种冷藏车的碳排放与燃料消耗量化方法,并构建了优化配送成本、保障客户服务水平和降低碳排放的多目标数学模型。最后,采用粒子群算法求解模型,同时对碳税和冷藏车车速进行灵敏度分析。结果表明... 针对碳税规制下的冷链物流配送问题,提出一种冷藏车的碳排放与燃料消耗量化方法,并构建了优化配送成本、保障客户服务水平和降低碳排放的多目标数学模型。最后,采用粒子群算法求解模型,同时对碳税和冷藏车车速进行灵敏度分析。结果表明,冷链物流配送企业的综合成本随碳税的增加而提高,适当提高冷藏车的车速有助于配送企业控制物流成本、保障客户服务水平,但车速过高会导致客户服务水平下降。该研究可以为冷链物流配送企业降低总成本、减少碳排放和提升客户服务水平提供实践指导。 展开更多
关键词 冷链物流 路径优化 粒子群算法 配送 碳税
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承德市矿泉水资源分布规律及其形成的地球化学条件 预览
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作者 苏宏建 杨瑞 +3 位作者 多晓松 赵婧 孙志辉 赵红瑞 《化工矿产地质》 CAS 2019年第1期27-34,共8页
承德作为京津冀水源涵养地,其天然矿泉水和山泉水等水资源丰富,分布广、流量大、水质优,且多为弱碱性或中性淡水,富含钾、钙、镁、锶、锂、锌、偏硅酸等多种矿物质及微量元素。通过对承德地区矿泉水资源分布情况的研究,总结不同类型的... 承德作为京津冀水源涵养地,其天然矿泉水和山泉水等水资源丰富,分布广、流量大、水质优,且多为弱碱性或中性淡水,富含钾、钙、镁、锶、锂、锌、偏硅酸等多种矿物质及微量元素。通过对承德地区矿泉水资源分布情况的研究,总结不同类型的矿泉水在承德地区的分布规律,并对不同类型矿泉水形成的地球化学条件做了阐述。 展开更多
关键词 矿泉水 分布规律 地球化学条件
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营卫析解及临床应用研究 预览
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作者 侯仙明 刘淑彦 +3 位作者 潘永梅 方敬 贾云芳 贾春生 《河北中医药学报》 2019年第2期9-13,39共6页
笔者对营卫的生成、分布与循行提出了一些新的认识:⑴明确了营气与卫气的生成源头及组成。即营气之源头在中焦脾胃,其组成包括:水谷之精气和自然之清气;卫气之源头在下焦肾,其组成包括:水谷之精气、自然之清气和肾中之精气。⑵明确提出... 笔者对营卫的生成、分布与循行提出了一些新的认识:⑴明确了营气与卫气的生成源头及组成。即营气之源头在中焦脾胃,其组成包括:水谷之精气和自然之清气;卫气之源头在下焦肾,其组成包括:水谷之精气、自然之清气和肾中之精气。⑵明确提出营气循行有两条路线,分别为经络路线与血脉路线。⑶以取象比类的方法对卫气循行的3种方式进行了分析,提出了卫气有2种运行状态,其一为全身散布,由内而外的运行状态;其二为循经运行,昼行于阳,夜行于阴,一日一夜五十周于身的运行模式。⑷以太极阴阳消长变化模型对卫气“昼行于阳,夜行于阴”进行了重新解读。⑸对于卫气昼行于阳的路线提出主干与分支说,其循行主干是:起于目,沿太阳膀胱经之主干下行至足小趾,然后由小趾入足心,上内踝,走跷脉上行复归于目。主要涉及足太阳膀胱经、足少阴肾经(一部分)与跷脉。其他循行的阳经均是分支。⑹提出卫气的循行方向存在多向性。另外,除了理论上的认识外,本文还对“避”“脉”“随”等相关文字对内经原文中的含义进行了重新解读。 展开更多
关键词 营卫 营气 卫气 生成 分布 循行
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鲍曼不动杆菌临床耐药、分布情况及感染影响因素研究 预览
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作者 张跃明 张传磊 胡丽华 《中国现代医生》 2019年第8期139-142,共4页
目的探讨本院分离的鲍曼不动杆菌的临床耐药情况及分布,并分析感染影响因素。方法采用纸片扩散实验法对获得的鲍曼不动杆菌予以药敏测验,并应用WHONET 5.6以及SPSS 20.0软件对鲍曼不动杆菌的分布、药敏情况予以分析,同时对鲍曼不动杆菌... 目的探讨本院分离的鲍曼不动杆菌的临床耐药情况及分布,并分析感染影响因素。方法采用纸片扩散实验法对获得的鲍曼不动杆菌予以药敏测验,并应用WHONET 5.6以及SPSS 20.0软件对鲍曼不动杆菌的分布、药敏情况予以分析,同时对鲍曼不动杆菌的感染影响因素予以单因素统计分析。结果本院2016年1月~2017年12月年培养出非重复性鲍曼不动杆菌共910株,呼吸道标本占71.21%,伤口、引流液及脓液、血液、尿液、脑脊液分别占9.45%、9.23%、2.31%、1.76%。本院鲍曼不动杆菌的科室分布,主要包括康复科、重症监护室、神经外科及神经内科。经药敏结果提示,鲍曼不动杆菌对替加环素、阿米卡星、左氧氟沙星、头孢哌酮/舒巴坦以及氨苄西林/舒巴坦的耐药率较低,其余临床常用的抗菌类药物对于鲍曼不动杆菌的耐药率均较高,其中美罗培南高达89.89%。感染影响因素主要包括格拉斯哥昏迷评分(GCS)≤8分、侵袭性操作、广谱抗菌药物以及患者住院时间≥14 d,差异有统计学意义(χ^2=7.469、7.469、9.593、7.836,P<0.05);而性别、年龄及激素治疗三项因素差异无统计学意义(P>0.05)。结论鲍曼不动杆菌具有较高耐药性,其感染主要影响因素为昏迷、侵袭性操作、广谱抗菌药物及住院时间较长,临床应针对各项因素予以有效的针对性预防。 展开更多
关键词 鲍曼不动杆菌 耐药 影响因素 分布情况
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The spatial distribution of major and trace elements of surface sediments in the northeastern Beibu Gulf of the South China Sea 预览
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作者 Qian Ge George Z Xue +3 位作者 Liming Ye Dong Xu Jianru Zhao Fengyou Chu 《海洋学报:英文版》 SCIE CAS CSCD 2019年第3期93-102,共10页
A multi-index analysis including grain size, major and trace elements is performed on the surface sediments from the northeastern Beibu Gulf to trace the sources of the sediments and to understand the controlling fact... A multi-index analysis including grain size, major and trace elements is performed on the surface sediments from the northeastern Beibu Gulf to trace the sources of the sediments and to understand the controlling factors for elements distribution. The mean grain size exhibits a wide variation ranging from 0.09Φ to 8.05Φ with an average value of 5.33Φ. The average contents of major elements descend in an order of c(SiO2)>c(Al2O3)>c(Fe2O3)>c(CaO)>c(MgO)>c(K2O)>c(Na2O)>c(TiO2)>c(P2O5)>c(MnO), while those of trace elements exhibit a descending order of c(Sr)>c(Rb)>c(V)>c(Zn)>c(Cr)>c(Pb)>c(Ni)>c(Cu)>c(As). On the basis of elementary distribution characteristics and statistical analyses, the study area is divided into the four zones: Zone I is located in the northeastern coastal area of the gulf, which receives large amount of fluvial materials from local rivers in Guangxi and Guangdong, China, and the Qiongzhou Strait;Zone Ⅱ is located in the center of the study area, where surface sediments exhibits a multiple source;Zone Ⅲ is located in the Qiongzhou Strait, where surface sediments are dominated by materials from the Zhujiang River and Hainan;Zone IV is located in the southwest of the study area, where surface sediments are mainly originated from the Red River and Hainan. The statistical analyses of sediment geochemical characteristics reveal that the grain size, which is mainly influenced by hydrodynamics and mineral composition of terrigenous materials, is the leading factor controlling the elementary distribution.Meanwhile, impacts from anthropogenic activities and marine biogenic process will also be taken into consideration. 展开更多
关键词 GRAIN size major and TRACE elements Beibu GULF spatial distribution sediment source
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A Historical Sedimentary Record of Mercury in a Shallow Eutrophic Lake: Impacts of Human Activities and Climate Change
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作者 Hanxiao Zhang Shouliang Huo +3 位作者 Kevin M. Yeager Beidou Xi Jingtian Zhang Fengchang Wu 《工程(英文)》 2019年第2期296-304,共9页
Mercury and its derivatives are hazardous environmental pollutants and could affect the aquatic ecosystems and human health by biomagnification. Lake sediments can provide important historical information regarding ch... Mercury and its derivatives are hazardous environmental pollutants and could affect the aquatic ecosystems and human health by biomagnification. Lake sediments can provide important historical information regarding changes in pollution levels and thus trace anthropogenic or natural influences. This research investigates the 100-year history of mercury (Hg) deposition in sediments from Chao Lake, a shallow eutrophic lake in China. The results indicate that the Hg deposition history can be separated into three stages (pre-1960s, 1960s–1980s, and post-1980s) over the last 100 years. Before the 1960s, Hg concentrations in the sediment cores varied little and had no spatial difference. Since the 1960s, the concentration of Hg began to increase gradually, and showed a higher concentration of contamination in the western half of the lake region than in the eastern half of the lake region due to all kinds of centralized human-input sources. The influences of anthropogenic factors and hydrological change are revealed by analyzing correlations between Hg and heavy metals (Fe, Co, Cr, Cu, Mn, Pb, and Zn), stable carbon and nitrogen isotopes (d13C and d15N), nutrients, particle sizes, and meteorological factors. The results show that Hg pollution intensified after the 1960s, mainly due to hydrological change, rapid regional development and urbanization, and the proliferation of anthropogenic Hg sources. Furthermore, the temperature, wind speed, and evaporation are found to interactively influence the environmental behaviors and environmental fate of Hg. 展开更多
关键词 Lake sediment MERCURY Vertical distribution ANTHROPOGENIC activities
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