检索结果-南通市图书馆

1980—2016年宁夏主要湖泊演变规律与驱动因素分析

在线全文

学校读者我要写书评

暂无评论

安徽农业科学 2024年第3期52卷 57-60,64页

作者：王生鑫徐涛张海涛段丽婷张华马思佳赵宇翔宁夏回族自治区水文水资源监测预警中心宁夏银川750000 中国水利水电科学研究院北京100038

基于1980—2016年宁夏地区湖泊数据,结合Google Earth影像处理、Mann-Kendall趋势分析法研究近37年宁夏湖泊空间分布特征和主要湖泊面积变化状况,并进一步探讨气候变化、径流条件和人类活动对湖泊演变的影响。结果表明:宁夏地区湖泊以... 详细信息

基于1980—2016年宁夏地区湖泊数据,结合Google Earth影像处理、Mann-Kendall趋势分析法研究近37年宁夏湖泊空间分布特征和主要湖泊面积变化状况,并进一步探讨气候变化、径流条件和人类活动对湖泊演变的影响。结果表明:宁夏地区湖泊以永久性淡水湖为主,主要分布在银川和石嘴山市。1980—2016年面积在1.00 km2以上的湖泊的总面积呈增加趋势;其中,有84%的湖泊面积呈现增加趋势,16%的湖泊面积呈减小趋势。宁夏湖泊面积变化是由自然因素和人为因素共同引起的,湖泊面积与年均气温、年降雨量的变化趋势相同,与年径流量的变化趋势相反;不同类型的人类活动对湖泊面积的影响不同,但总体上对湖泊面积增加起到了促进作用。

关键词：湖泊演变规律驱动因素宁夏

维普期刊数据库博看期刊

Simultaneous Determination of Catecholamines and Related Metabolites by Capillary Electrophoresis with Amperometric Detection

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2013年第5期29卷 850-853页

作者： zhang hai-tao LI Zhuo zhang Jun-bo zhang Yang YE Jian-nong CHU Qing-cui zhang Mei-jiang Department of Chemistry East China Normal University Shanghai 200241 P. R. China Key Laboratory of Adolescent Health Assessment and Exercise Intervention Ministry of Education School of Sports and Health Care East China Normal University Shanghai 200062 P R. China

An electrophoretic method was developed for the determination of several important catecholamine markers, namely norepinephrine, epinephrine, dopamine, metanephrine, vanillylmandelic acid and homovanillic acid in urine samples. Under the optimum conditions, the six marker compounds could be well separated with the major coexisting interference compound uric acid within 24 rain at a separation voltage of 16 kV in a borate running buffer （80 mmol/L, pH=9.48）. Highly linear response can be obtained over three orders of magnitude for the above markers with the low limits of detection ranging from 1.0 ng/mL to 5.0 ng/mL（S/N=3）. The proposed capillary electrophoresis with amperometric detection（CE-AD） method has been used to simultaneously determine the six catecholamine markers in urine samples of healthy volunteers and patients suffering from different diseases avoiding redundant measurements and high assay cost; and the electrochemical profiles can suggest more diagnostic information of multiple diseases, which provides a promising and convenient entry into primary diagnoses of several clinical diseases.

关键词： Amperometric detection Capillary electrophoresis Catecholamine Metabolic marker Urine

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

支气管哮喘患儿继发肺部感染的肠道菌群特征

中华医院感染学杂志 2024年第18期34卷 2780-2784页

作者：张海涛王玉石苗苗袁丽萍胡波杨泽玉安徽省儿童医院呼吸科安徽合肥230051 安徽医科大学第一附属医院儿科安徽合肥230022

目的探讨支气管哮喘患儿继发肺部感染的肠道菌群结构及功能特征。方法选取2022年2月-2024年2月安徽省儿童医院呼吸科收治的29例哮喘继发肺部感染患儿为感染组,随机选取同期入院治疗的31例单纯哮喘患儿为非感染组,检测两组患儿炎症细胞... 详细信息

目的探讨支气管哮喘患儿继发肺部感染的肠道菌群结构及功能特征。方法选取2022年2月-2024年2月安徽省儿童医院呼吸科收治的29例哮喘继发肺部感染患儿为感染组,随机选取同期入院治疗的31例单纯哮喘患儿为非感染组,检测两组患儿炎症细胞因子白细胞介素(IL)-1β、IL-2R、IL-6、IL-8、IL-10和肿瘤坏死因子-α(TNF-α)水平,使用宏基因组高通量技术对两组患儿新鲜粪便标本进行肠道菌群测序并进行生物信息分析。结果感染组患儿炎症细胞因子IL-1β、IL-2R、IL-6、IL-8和TNF水平高于非感染组(P<0.05),肠道菌群的α多样性和β多样性显著降低(P<0.05);两组在属水平上的优势菌为拟杆菌属(Bacteroides)、普雷沃菌属(Prevotella)、另枝菌属(Alistipes)和真杆菌属(Eubacterium)等,其中感染组Prevotella、巨单细胞菌属(Megamonas)、阿克曼菌属(Akkermansia)和坦纳菌属(Tannerella)菌群相对丰度较高,非感染组中副拟杆菌属(Parabacteroides)、小类杆菌属(Dialister)、小类杆菌属(Faecalibacterium)、瘤胃球菌属(Ruminococcus)和Alistipes相对丰度较高;两组差异优势功能基因主要集中在新陈代谢(包括外源物质的生物降解和代谢、能量代谢、脂质代谢等)方面。结论支气管哮喘患儿继发肺部感染血清炎症细胞因子水平升高,且肠道微生物多样性及物种组成均发生了改变。

关键词：支气管哮喘肺部感染肠道菌群肠-肺轴宏基因组学细胞因子

Effect of low-speed waterjet pressure on the rock-breaking performance of unsubmerged cavitating abrasive waterjet

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第4期21卷 2638-2649页

作者： Chen-Xing Fan Deng Li Yong Kang hai-tao zhang Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan University School of Power and Mechanical Engineering Wuhan University

Unsubmerged cavitating abrasive waterjet(UCAWJ) has been shown to artificially create a submerged environment that produces shear cavitation, which effectively enhances rock-breaking performance. The shear cavitation generation and collapse intensity depend on the pressure difference between the intermediate high-speed abrasive waterjet and the coaxial low-speed waterjet. However, the effect of the pressure of the coaxial low-speed waterjet is pending. For this purpose, the effect of low-speed waterjet pressure on rock-breaking performance at different standoff distances was experimentally investigated,and the effects of erosion time and ruby nozzle diameter on erosion performance were discussed. Finally,the micromorphology of the sandstone was observed at different locations. The results show that increased erosion time and ruby nozzle diameter can significantly improve the rock-breaking performance. At different standoff distances, the mass loss increases first and then decreases with the increase of low-speed waterjet pressure, the maximum mass loss is 10.4 g at a low-speed waterjet pressure of0.09 MPa. The surface morphology of cavitation erosion was measured using a 3D profiler, the increase in both erosion depth and surface roughness indicated a significant increase in the intensity of the shear cavitation collapse. At a low-speed waterjet pressure of 0.18 MPa, the cavitation erosion surface depth can reach 600 μm with a roughness of 127 μm.

关键词： Rock-breaking Coaxial low-speed waterjet pressure Abrasive waterjet Cavitation Unsubmerged environment

考虑客户用电安全隐患的配电网脆弱线路风险自动预警方法

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

自动化技术与应用 2024年第2期43卷 45-48,67页

作者：王超张海涛郑皓天贾蓉蓉国网陕西省电力公司营销服务中心(计量中心) 陕西西安710000

脆弱线路作为配电网的重要组成部分,是保证电网安全与用户安全的关键环节。为此,从客户用电安全隐患角度出发,提出配电网脆弱线路风险自动预警方法。基于电气介数模型与线路潮流传输最大值,建立有功潮流介数模型,降序排列有功潮流介数,... 详细信息

脆弱线路作为配电网的重要组成部分,是保证电网安全与用户安全的关键环节。为此,从客户用电安全隐患角度出发,提出配电网脆弱线路风险自动预警方法。基于电气介数模型与线路潮流传输最大值,建立有功潮流介数模型,降序排列有功潮流介数,识别脆弱线路。利用脆弱线路形成最小风险的目标函数模型来评估风险,依据风险期望值与控制决策,划分风险评估等级与预警等级,采用神经网络模型,实现风险自动预警。实验结果表明,所提方法的脆弱线路识别结果与风险自动预警效果较好,能够正确作出风险预警,且实践优势显著。

关键词：客户用电安全隐患配电网脆弱线路风险自动预警有功潮流神经网络

Determination of Xenon in Air by a Pulse-discharge Helium Ionization Detector

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2012年第5期28卷 814-817页

作者： CHEN Zhan-ying CHANG Yin-zhong LIU Shu-jiang zhang hai-tao WANG Shi-lian LI Qi CTBT Beijing National Data Centre&Beijing Radionuclide Laboratory Beijing 100085P.R.China Northwest Institute of Nuclear Technology Xi'an 710024P.R.China

A pulse-discharge helium ionization detector（Valco, PD-D3-I） was used to measure xenon concentration in air. The dependences of the detector relative response on various gas chromatograph parameters were investigated. Based on the well prepared gas connections for the detector system and optimized gas chromatography（GC） working conditions, the atmospheric xenon concentration could be measured by the cheap GC method with a detection level of 0.7×10-9（parts by volume）. Moreover, the xenon concentration in the ground level air around our laboratory was measured with the result of 0.085×10-6（parts by volume） and RSD of 0.91%.

关键词： Pulse-discharge helium ionization detector Xenon Gas chromatography(GC) Air analysis

Reinforcement Learning-Based MAS Interception in Antagonistic Environments

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 270-272页

作者： Siqing Sun Defu Cai hai-tao zhang Ning Xing the School of Artificial Intelligence and Automation the MOE Engineering Research Center of Autonomous Intelligent Unmanned Systemsthe Guangdong Engineering Technology Research Center of Fully Autonomous Unmanned Surface VehiclesHuazhong University of Science and TechnologyWuhan 430074China the State Grid Hubei Electric Power Research Institute Wuhan 430074China IEEE

Dear Editor, As a promising multi-agent systems(MASs) operation, autonomous interception has attracted more and more attentions in these years, where defenders prevent intruders from reaching *** far, most of the relevant methods are applied in ideal environments without agent damages. As a remedy, this letter proposes a more realistic interception method for MASs suffered by damages.

关键词： agent MAS destination

A New Exponential Stability Condition for Delayed Systems with Markovian Switching

在线全文

学校读者我要写书评

暂无评论

自动化学报 2010年第7期36卷 1025-1028页

作者： CONG Shen zhang hai-tao ZOU Yun School of Mechanical and Electrical Engineering Heilongjiang University Harbin 150080 P.R.China Engineering Institute of Corps of Engineers PLA University of Science and Technology Nanjing 210094 P.R.China School of Automation Nanjing University of Science and Technology Nanjing 210094 P.R.China

This paper discusses the problem of exponential mean-square stability analysis for delayed systems with Markovian switching.A mode-dependent Lyapunov-Krasovskii functional taking a rather general form is used. The statistical property of Markov process is used to derive the di-erential of the functional. Considering this and applying the free-weighting matrix technique, a new stability criterion is obtained by means of linear matrix inequalities. The effectiveness of the proposed result is numerically demonstrated by examples provided finally.

关键词：时滞系统稳定性分析指数均方马尔可夫

基于视觉引导双机器人的柔性堆叠焊接制造系统

在线全文

学校读者我要写书评

暂无评论

世界有色金属 2024年第14期 22-25页

作者：程金刚柏兴旺刘梦茹张海涛南华大学机械工程学院湖南衡阳421001

机器人焊接是自动化焊接系统的主要形式。尽管机器视觉、智能示教、离线编程等技术的应用大幅提高了焊接系统的制造柔性,但是,现有的机器人焊接还并不能完全适应于小批量和定制化需求的产品制造,制造柔性需要进一步提升。针对这一问题,... 详细信息

机器人焊接是自动化焊接系统的主要形式。尽管机器视觉、智能示教、离线编程等技术的应用大幅提高了焊接系统的制造柔性,但是,现有的机器人焊接还并不能完全适应于小批量和定制化需求的产品制造,制造柔性需要进一步提升。针对这一问题,提出了柔性堆叠焊接制造方法,并设计了基于视觉引导双机器人的柔性堆叠焊接制造系统。在柔性堆叠焊接制造中,目标焊接结构被拆解为堆叠件的序列,抓取机器人在3D视觉引导下进行识别、抓取和装配,焊接机器人则在激光焊缝跟踪系统的辅助下进行同步焊接。双机器人如人类左右手进行协同作业,自下而上地逐件堆叠焊接而制造获得目标焊接结构。深入研究了堆叠件抓取点计算、点云匹配、机器人位姿配准等算法,并通过制造案例分析验证了系统有效性和制造精度。

关键词：柔性堆叠机器视觉引导模板匹配