检索结果-南通市图书馆

A LMI-Based Approach for Robust Stabilization of Uncertain Linear Continuous Time Singular Markov Switched Systems with Time Delays

在线全文

学校读者我要写书评

暂无评论

A LMI-Based Approach for Robust Stabilization of Uncertain L...

Impact of Pd single-site coordination structure on catalytic performance for semihydrogenation of acetylene

第25届中国控制会议

作者： gao lijun, wu yuqiang Institute of Automation, Qufu Normal University, Rizhao 276826

＜正＞The stability and stabilization of linear continuous time singular Markov switched systems with time delay are investigated. Based on the linear matrix inequality method （LMIs） , the robust stability of uncertain linear stochastic delay system is guaranteed irrespective of the value of the time delay. Then the proposed theory can be extended to discuss the robust stabilization of uncertain stochastic differential delay systems. The gains of this controller are the solution of some linear matrix inequalities. Final numerical example is solved to show the effectiveness and validness of the theoretical results.

关键词： Markov switched systems Stabilization LMI Time delay

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Nano Research 2024年第9期17卷 8243-8249页

作者： Yu Zeng Minqi Xia Fujie gao Changkai Zhou Xueyi Cheng Liwei Liu Liu Jiao Qiang wu Xizhang Wang lijun Yang Yining Fan Zheng Hu Key Laboratory of Mesoscopic Chemistry of MOE and Jiangsu Provincial Laboratory for Nanotechnology School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Semihydrogenation of trace acetylene in an ethylene gas stream is a vital step for the industrial production of polyethylene,in which Pd single-site catalysts(SSCs)have great ***,two Pd SSCs with different coordination structures are prepared on hierarchical nitrogen-doped carbon nanocages(hNCNC)by regulating the nitrogen species with or without using *** using dicyandiamide,the obtained Pd1-Ndicy/hNCNC SSC features the coordinated Pd by two pyridinic N and two pyrrolic N(PdN^(py)_(2)N^(pr)_(2)).Without using dicyandiamide,the obtained Pd1/hNCNC SSC features the coordinated Pd by pyridinic N and C(PdN^(py_(x)C_(4-x)),x=1-4).The former exhibits an 18-fold increase in catalytic activity compared to the *** results reveal the abundant unoccupied orbital states above the Fermi level of moiety,which can facilitate the activation of substrate molecules and dynamics of acetylene hydrogenation as supported by the combined theoretical and experimental *** addition,PdN^(py)_(2)N^(pr)_(2)the moiety presents a favorable desorption of ***,the Pd1-Ndicy/hNCNC SSC exhibits high C2H2 conversion(99%)and C2H4 selectivity(87%)at 160℃.This study demonstrates the impact of Pd single-site coordination structure on catalytic performance,which is significant for the rational design of advanced Pd SSCs on carbon-based supports.

关键词： coordination structure hierarchical nitrogen-doped carbon nanocages palladium semihydrogenation of acetylene singlesite catalysts

MXene Sediment-Based Poly(vinyl alcohol)/Sodium Alginate Aerogel Evaporator with Vertically Aligned Channels for Highly Efficient Solar Steam Generation

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

Nano-Micro Letters 2024年第10期16卷 638-654页

作者： Tian Wang Meng Li Hongxing Xu Xiao Wang Mingshu Jia Xianguang Hou Shuai gao Qingman Liu Qihang Yang Mingwei Tian lijun Qu Zhenhua Song Xiaohu wu Lili Wang Xiansheng Zhang Shandong Key Laboratory of Medical and Health Textile Materials College of Textiles and ClothingState Key Laboratory of Bio-Fibers and Eco-TextilesResearch Center for Intelligent and Wearable TechnologyQingdao UniversityQingdao 266071People's Republic of China Department of Pharmacology Qingdao University School of PharmacyQingdao UniversityQingdao 266071People's Republic of China Shandong Institute of Advanced Technology Jinan 250100People's Republic of China College of Electromechanical Engineering Qingdao University of Science and TechnologyQingdao 266061People's Republic of China

Solar-driven interfacial evaporation from seawater is considered an effective way to alleviate the emerging freshwater crisis because of its green and environmentally friendly ***,developing an evaporator with high efficiency,stability,and salt resistance remains a key ***,with an internal photothermal conversion efficiency of 100%,has received tremendous research interest as a photothermal ***,the process to prepare the MXene with monolayer is inefficient and generates a large amount of“waste”MXene sediments(MS).Here,MXene sediments is selected as the photothermal material,and a three-dimensional MXene sediments/poly(vinyl alcohol)/sodium alginate aerogel evaporator with vertically aligned pores by directional freezing method is innovatively *** vertical porous structure enables the evaporator to improve water transport,light capture,and high evaporation *** swabs and polypropylene are used as the water channel and support,respectively,thus fabricating a self-floating *** evaporator exhibits an evaporation rate of 3.6 kg m^(-2)h^(-1)under one-sun illumination,and 18.37 kg m^(-2)of freshwater is collected in the condensation collection device after 7 h of outdoor sun *** evaporator also displays excellent oil and salt *** research fully utilizes“waste”MS,enabling a self-floating evaporation device for freshwater collection.

关键词： MXene sediments Porous structure Desalination Self-floating

IDH1 mutation inhibits differentiation of astrocytes and glioma cells with low oxoglutarate dehydrogenase expression by disturbingα-ketoglutarate-related metabolism and epigenetic modification

在线全文

学校读者我要写书评

暂无评论

Life Metabolism 2024年第2期3卷 24-37页

作者： Yuanlin Zhao Ying Yang Risheng Yang Chao Sun Xing gao Xiwen Gu Yuan Yuan Yating Nie Shenhui Xu Ruili Han lijun Zhang Jing Li Peizhen Hu Yingmei Wang Huangtao Chen Xiangmei Cao Jing wu Zhe Wang Yu Gu Jing Ye State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers Department of PathologyXijing Hospital and School of Basic MedicineFourth Military Medical UniversityXi’anShaanxi 710032China Department of Pathology Air Force Hospital of Southern Theater CommandGuangzhouGuangdong 510000China Department of Neurology Tangdu HospitalFourth Military Medical UniversityXi’anShaanxi 710038China Department of Clinical Diagnosis Tangdu HospitalFourth Military Medical UniversityXi’anShaanxi 710038China Department of Neurosurgery the Second Affiliated Hospital of Xi’an Jiaotong UniversityXi’anShaanxi 710004China Department of Pathology School of Basic Medical SciencesNingxia Medical UniversityYinchuanNingxia 750004China Institute of Analytical Chemistry and Instrument for Life Science The Key Laboratory of Biomedical Information Engineering of Ministry of EducationSchool of Life Science and TechnologyXi’an Jiaotong UniversityXi’anShaanxi 710049China

Isocitrate dehydrogenase(IDH)mutations frequently occur in lower-grade gliomas and secondary *** IDHs exhibit a gain-of-function activity,leading to the production of D-2-hydroxyglutarate(D-2HG)by reducing α-ketoglutarate(α-KG),a central player in metabolism and epigenetic ***,the role ofα-KG homeostasis in IDH-mutated gliomagenesis remains *** this study,we found that low expression of oxoglutarate dehydrogenase(OGDH)was a common feature in IDH-mutated gliomas,as well as *** low expression of OGDH resultedin the accumulation of α-KG and promoted astrocyte ***,IDH1 mutation significantly reducedα-KG levels and increased glutaminolysis and DNA/histone methylation in *** metabolic and epigenetic alterations inhibited astrocyte maturation and led to cortical dysplasia in ***,our results also indicated that reduced OGDH expression can promote the differentiation of glioma cells,while IDH1 mutations impeded the differentiation of glioma cells with low OGDH by reducing the accumulation ofα-KG and increasing ***,we found that l-glutamine increasedα-KG levels and augmented the differentiation-promoting effects of AGI5198,an IDH1-mutant inhibitor,in IDH1-mutant glioma ***,this study reveals that low OGDH expression is a crucial metabolic characteristic of IDH-mutant gliomas,providing a potential strategy for the treatment of IDH-mutant gliomas by targetingα-KG homeostasis.

关键词： α-ketoglutarate IDH1 mutation OGDH l-glutamine gliomas

Exponential stability of impulsive jump linear systems with Markov process

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2007年第2期18卷 304-310页

作者： gao Liju wu yuqiang Inst. of Automation Qufu Normal Univ. Qufu 273165 P. R. China

The exponential stability is investigated for a class of continuous time linear systems with a finite state Markov chain form process and the impulsive jump at switching moments. The conditions, based on the average dwell time and the ratio of expectation of the total time running on all unstable subsystems to the expectation of the total time running on all stable subsystems,assure the exponential stability with a desired stability degree of the system irrespective of the impact of impulsive jump. The uniformly bounded result is realized for the case in which switched system is subjected to the impulsive effect of the excitation signal at some switching moments.

关键词： Jump systems Exponential stability Average dwell time Markov process.

在线全文

学校读者我要写书评

暂无评论

深部煤层孔隙结构与流体差异赋存特征研究

煤田地质与勘探 2024年第8期52卷 89-100页

作者：吴见孙强石雪峰高丽军中联煤层气有限责任公司北京100016 三气共采省技术创新中心山西太原030008 中海油能源发展股份有限公司工程技术分公司天津300457

【目的】鄂尔多斯盆地东缘已打破深部煤层气勘探禁区,多个区块呈现“单点突破、区域差异开发”特征,深部煤储层孔裂隙结构作为流体赋存与产出的物质空间,对于深部煤层气区块差异开发至关重要。【方法】系统采集鄂尔多斯盆地东缘神府区... 详细信息

【目的】鄂尔多斯盆地东缘已打破深部煤层气勘探禁区,多个区块呈现“单点突破、区域差异开发”特征,深部煤储层孔裂隙结构作为流体赋存与产出的物质空间,对于深部煤层气区块差异开发至关重要。【方法】系统采集鄂尔多斯盆地东缘神府区块深部煤样品,基于常规孔渗物性测试、CO_(2)吸附、低温N2吸附、压汞和核磁共振等测试,以神府区块8+9号煤为例,系统总结深煤层孔隙结构及流体赋存模式。【结果和结论】结果表明:(1)深部煤孔隙结构差异较大,神府煤介孔−宏孔均发育,多为墨水瓶型和开放型孔。综合认为中阶煤孔隙结构的跨尺度效应稍有减弱,相对有利扩散、渗流。(2)中阶煤吸附能力降低,等温吸附曲线高压段曲线平缓,初期解吸效率低;含水饱和度增高,其介孔−宏孔的束缚水含量较高导致可动水孔隙率减小,降低了游离气的储集空间。(3)研究区存在“宏孔−微裂缝主控的游离气−自由水赋存”型、“微孔−介孔−宏孔主控的吸附气−束缚水赋存”型两类气水赋存模式,导致煤层气排采差异明显,其中“宏孔−微裂缝主控的游离气−自由水赋存”型是深部煤层气快速高产模式,该模式具有“见气时间短、中高产气、低产水”的生产特征,且由于应力对中大孔−微裂缝的伤害较强,建议该模式下的气井排采需适当控制排采速度以减小储层伤害,防止产量陡降;“微孔−介孔−宏孔主控的吸附气束缚水赋存”型模式具有“短期排水、缓慢见气”生产特征,排采仍需遵循“缓慢、连续”原则保证气井稳产;此外,由于孔隙以微孔、介孔为主,束缚水含量高,气井短期难获高产,需进一步探索加大压裂改造规模提高该类气藏产量。

关键词：神府区块深部煤层气多尺度孔隙结构气水赋存模式生产特征

同方期刊数据库

向心透平发电膨胀机静压气体轴承设计与承载特性分析

在线全文

学校读者我要写书评

暂无评论

润滑与密封 2024年第6期49卷 145-153页

作者：武潭蔡树亭高晓蕾郭保国张黎君郑州轻工业大学能源与动力工程学院河南郑州450001 郑州大学力学与安全工程学院河南郑州450001 河南省锅炉压力容器检验技术科学研究院河南郑州450016 河南应用技术职业学院化学工程学院河南郑州450001

为提升有机朗肯循环(organic Rankine cycle,ORC)系统向心透平发电膨胀机静压气体轴承的承载力与刚度,采用表压比法设计了以R245fa为润滑工质的静压气体轴承,分析转子偏心率、供气孔尺寸、进气压力对静压气体轴承承载力与刚度的影响。... 详细信息

为提升有机朗肯循环(organic Rankine cycle,ORC)系统向心透平发电膨胀机静压气体轴承的承载力与刚度,采用表压比法设计了以R245fa为润滑工质的静压气体轴承,分析转子偏心率、供气孔尺寸、进气压力对静压气体轴承承载力与刚度的影响。实验结果表明:在相同供气压力下,轴承承载力与刚度随着转速的增大而增大;在相同转速下,0.7 MPa供气压力相对于其他气体供气压力轴承的承载力与刚度略高;静压气体轴承的偏心率越大承载力越大;相同供气孔直径下,静压气体轴承的承载力与刚度随着转速的升高而升高;随供气孔直径增大,静压气体轴承的承载力和刚度也随之增大。

关键词：静压气体轴承膨胀机承载力刚度有机朗肯循环

1050A铝合金在山东不同典型环境中的大气腐蚀行为特征研究

在线全文

学校读者我要写书评

暂无评论

中国腐蚀与防护学报 2024年第4期44卷 1055-1063页

作者：樊志彬高智悦宗立君吴亚平李辛庚姜波杜宝帅国网山东省电力公司电力科学研究院济南250001

在山东青岛、东营、威海、潍坊等典型大气环境中对1050A铝合金进行了为期42个月的自然暴晒试验。暴晒一定周期试样取回,利用宏观形貌、微观形貌、腐蚀速率、腐蚀产物分析和电化学分析等手段研究了其在山东典型大气环境中的腐蚀行为特征... 详细信息

在山东青岛、东营、威海、潍坊等典型大气环境中对1050A铝合金进行了为期42个月的自然暴晒试验。暴晒一定周期试样取回,利用宏观形貌、微观形貌、腐蚀速率、腐蚀产物分析和电化学分析等手段研究了其在山东典型大气环境中的腐蚀行为特征。结果表明:1050A铝合金具有较好的耐大气腐蚀性能,在山东青岛、东营、威海和潍坊不同典型大气环境中暴晒42个月后,腐蚀产物主要以Al的氧化物和氢氧化物为主;相对来说腐蚀速率东营>威海>青岛>潍坊,其腐蚀速率随暴晒时间延长而降低,这可能有腐蚀产物膜有关。通过激光共聚焦微观形貌分析可见,腐蚀以局部腐蚀为主,暴晒42个月以后,点蚀坑主要分布在10μm以下。电化学阻抗结果表明在暴晒初期试样正反面腐蚀程度存在一定的差异,随着暴晒时间延长差异减弱。

关键词：铝合金大气腐蚀腐蚀速率腐蚀特征

全国地方病防治机构氟化物检测实验室外质控考核结果分析

在线全文

学校读者我要写书评

暂无评论

中华地方病学杂志 2024年第2期43卷 141-147页

作者：纪晓红王伟赵丽军高琳武辽伟李城王健裴俊瑞高彦辉中国疾病预防控制中心地方病控制中心地氟病防治研究所哈尔滨150081 哈尔滨医科大学哈尔滨150081

目的分析2006-2023年全国地方病防治机构氟化物检测实验室外质控考核情况,掌握全国各省、市、县级地方病防治机构氟化物检测实验室氟检测外质控能力,确保全国地方性氟中毒监测数据的准确性和可靠性。方法采用回顾性分析,对2006-2023年,... 详细信息

目的分析2006-2023年全国地方病防治机构氟化物检测实验室外质控考核情况,掌握全国各省、市、县级地方病防治机构氟化物检测实验室氟检测外质控能力,确保全国地方性氟中毒监测数据的准确性和可靠性。方法采用回顾性分析,对2006-2023年,所有全国地方病防治机构氟化物检测实验室外质控考核结果进行汇总分析。其中2006-2008年的考核结果,采用Grubbs法检验异常值;Cochran法检验方差齐性,剔除不合格实验室的考核数据,计算总平均值和总标准差;Z比分法检验实验室考核情况,采用│Z│<3的结果进行统计和判定。2009-2023年的考核结果来自所有实验室,其中2010年按上、下半年进行两次,其余年份每年1次。采用稳健统计,分别计算各实验室的Z比分数,当│Z│≤2时,考核结果为合格;当2<│Z│<3时,考核结果为基本合格;当│Z│≥3时,考核结果为不合格,公议值来自所有参加考核的实验室。结果从2006年质控运行之初到2023年,参加外质控考核的实验室数量明显增加。其中参加水氟考核的实验室由2006年的30个增加到2023年的1277个,参加尿氟考核的实验室由29个增加到497个;参加砖茶氟考核的实验室由2014年的43个增加到2023年的193个。考核结果显示,当│Z│<3时,全国地方病防治机构氟化物检测实验室水氟外质控总合格率为95.2%,其中最低是2008年为87.1%(27/31)最高是2014年为100.0%(394/394);当│Z│≤2时,总的反馈合格率为88.4%,其中2010年上半年最低,为79.3%(288/363),2014年最高,为99.5%(392/394)。考核结果显示,当│Z│<3时,全国地方病防治机构氟化物检测实验室尿氟外质控总合格率为98.0%,其中2006、2007年最低,均为86.2%(25/29),是2014年最高,为100.0%(68/68);当│Z│≤2时,总合格率为93.7%,其中最低是2010年下半年为86.5%(64/74),最高是2014年为100%(68/68)。考核结果显示,当│Z│<3时,全国地方病防治机构氟化物检测实验室砖茶氟外质控总合格率为95.4%,其中最低是2023年为85.0%(164/193),2014、2015、2016年最高,为100.0%(43/43、51/51、79/79);当│Z│≤2时,总合格率为89.2%,其中2017年最低,为72.7%(32/44),2014年最高,为100.0%(43/43)。2009-2023年水氟检测考核全部合格的省级实验室共21个,其中市、县级实验室全部合格的省份共3个;尿氟检测考核全部合格的省级实验室共11个,其中市、县级实验室全部合格的省份仅1个;2014-2023年茶氟检测考核全部合格的省级实验室共5个,无市、县级实验室全部合格的省份。结论2006-2023年,参加外质控考核的氟化物检测实验室数量逐年增加,大部分省、市、县级实验室均具有较好的氟化物检测能力,能够满足地方病防治监测的检测需求;对于部分存在问题的实验室,要有针对性地进行整改,提高检测质量,以期为地方性氟中毒病区监测工作提供更好的技术保障。

关键词：地方病氟实验室质控考核回顾分析