检索结果-南通市图书馆

Breeding ecology of ground tits in northeastern Tibetan plateau, with special reference to cooperative breeding system

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2011年第6期57卷 751-757页

作者： xin LU Ran HUO Yang LI Wenbo liao Chen WANG Department of Zoology College of Life Sciences Wuhan University Wuhan 430072 China

Data on breeding ecology of a color-band marked population of the ground tit Parus humilis were collected in north Qinghai on the Tibetan plateau, during 2008 and 2009. In spring the birds excavated 0.8-3.2 m long nesting burrows under the ground. First-egg laying occurred between late April and late June during which a pair produced one brood. Incubation was done by female alone for 15-16 days and nestling-feeding by both sexes and helpers in any for 23-25 days. Average brood size at fledging was 5.8 （＋ 1.4 SD, 3-8） and all the 27 observed nesting attempts fledged at least one young. At the population level, brood sex ratio did not differ from 1：1. The birds are a territory-living resident, with annual resight rates being 48% （22 of 46） in adult breeders and 10% （7 of 67） in yearlings. Pairs were socially monogamous, of which 23% （9 of 40） contained one and some- times two male helpers, most likely being philopatric sons of the breeders. The formation of cooperative groups is similar to the population in central Tibet but differs from that in south Guansu where breeding ground tits exhibit a high level of annual turnover

关键词： Burrow-nesting Cooperative breeding Life history Parus humilis Tibetan plateau

Human-induced pluripotent stem cell-derived neural stem cell exosomes improve blood-brain barrier function after intracerebral hemorrhage by activating astrocytes via PI3K/AKT/MCP-1 axis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第2期20卷 518-532页

作者： Conglin Wang Fangyuan Cheng Zhaoli Han Bo Yan Pan liao Zhenyu Yin xintong Ge Dai Li Rongrong Zhong Qiang Liu Fanglian Chen Ping Lei Department of Geriatrics Tianjin Medical University General HospitalTianjinChina School of Medicine Nankai UniversityTianjinChina Tianjin Neurological Institute TianjinChina

Cerebral edema caused by blood-brain barrier injury after intracerebral hemorrhage is an important factor leading to poor ***-induced pluripotent stem cell-derived neural stem cell exosomes(hiPSC-NSC-Exos)have shown potential for brain injury repair in central nervous system *** this study,we explored the impact of hiPSC-NSC-Exos on blood-brain barrier preservation and the underlying *** results indicated that intranasal delivery of hiPSC-NSC-Exos mitigated neurological deficits,enhanced blood-brain barrier integrity,and reduced leukocyte infiltration in a mouse model of intracerebral ***,hiPSC-NSC-Exos decreased immune cell infiltration,activated astrocytes,and decreased the secretion of inflammatory cytokines like monocyte chemoattractant protein-1,macrophage inflammatory protein-1α,and tumor necrosis factor-αpost-intracerebral hemorrhage,thereby improving the inflammatory *** sequencing indicated that hiPSC-NSC-Exo activated the PI3K/AKT signaling pathway in astrocytes and decreased monocyte chemoattractant protein-1 secretion,thereby improving blood-brain barrier *** with the PI3K/AKT inhibitor LY294002 or the monocyte chemoattractant protein-1 neutralizing agent C1142 abolished these *** summary,our findings suggest that hiPSC-NSC-Exos maintains blood-brain barrier integrity,in part by downregulating monocyte chemoattractant protein-1 secretion through activation of the PI3K/AKT signaling pathway in astrocytes.

关键词： AKT astrocyte blood-brain barrier cerebral edema exosomes human-induced pluripotent stem cells intracerebral hemorrhage neural stem cells neuroinflammation PI3K

Optimal stopping time on discounted semi-Markov processes

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2021年第2期16卷 303-324页

作者： Fang CHEN Xianping GUO Zhong-wei liao School of Mathematics Sun Yat-Sen UniversityGuangzhou 510275China College of Education for the Future Beijing Normal UniversityBeijing 100875China

This paper attempts to study the optimal stopping time for semi- Markov processes (SMPs) under the discount optimization criteria with unbounded cost rates. In our work, we introduce an explicit construction of the equivalent semi-Markov decision processes (SMDPs). The equivalence is embodied in the expected discounted cost functions of SMPs and SMDPs, that is, every stopping time of SMPs can induce a policy of SMDPs such that the value functions are equal, and vice versa. The existence of the optimal stopping time of SMPs is proved by this equivalence relation. Next, we give the optimality equation of the value function and develop an effective iterative algorithm for computing it. Moreover, we show that the optimal and ε-optimal stopping time can be characterized by the hitting time of the special sets. Finally, to illustrate the validity of our results, an example of a maintenance system is presented in the end.

关键词： Optimal stopping time semi-Markov processes(SMPs) value function semi-Markov decision processes(SMDPs) optimal policy iterative lgorithm

Application of a Novel Method for Machine Performance Degradation Assessment Based on Gaussian Mixture Model and Logistic Regression

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2011年第5期24卷 879-884页

作者： LIU Wenbin ZHONG xin LEE Jay liao Linxia ZHOU Min Chemical Safety Engineering Research Center of Ministry of Education Beijing University of Chemical Technology Beijing 100029 China The First Research Institute of Ministry of Public Security Beijing 100048 China National Science Foundation Industry/University Cooperative Research Center of Intelligent Maintenance Systems University of Cincinnati Cincinnati OH 45221 USA China National Petroleum Corporation Beijing 100007 China

The currently prevalent machine performance degradation assessment techniques involve estimating a machine＇s current condition based upon the recognition of indications of failure features,which entail complete data collected in different ***,failure data are always hard to acquire,thus making those techniques hard to be *** this paper,a novel method which does not need failure history data is *** packet decomposition（WPD） is used to extract features from raw signals,principal component analysis（PCA） is utilized to reduce feature dimensions,and Gaussian mixture model（GMM） is then applied to approximate the feature space ***-channel confidence value（SCV） is calculated by the overlap between GMM of the monitoring condition and that of the normal condition,which can indicate the performance of ***,multi-channel confidence value（MCV）,which can be deemed as the overall performance index of multi-channel,is calculated via logistic regression（LR） and that the task of decision-level sensor fusion is also *** SCV and MCV can serve as the basis on which proactive maintenance measures can be taken,thus preventing machine *** method has been adopted to assess the performance of the turbine of a centrifugal compressor in a factory of Petro-China,and the result shows that it can effectively complete this *** proposed method has engineering significance for machine performance degradation assessment.

关键词： performance degradation assessment Gaussian mixture model logistic regression proactive maintenance sensor fusion

Boosting the piezoelectric property of relaxor ferroelectric single crystal via active manipulation of defect dipole polarization

在线全文

学校读者我要写书评

暂无评论

Journal of Materiomics 2023年第1期9卷 166-173页

作者： Qingyuan Hu Huimin liao xin Liu Li Jin Kexin Song Yongyong Zhuang Zhuo Xu Vladimir Ya Shur Xiaoyong wei Electronic Materials Research Laboratory Key Laboratory of the Ministry of Education&International Center for Dielectric ResearchSchool of Electronic ImformationXi'an Jiaotong UniversityXi'an710049China School of Natural Sciences and Mathematics Ural Federal UniversityEkaterinburg620000Russia

To further enhance the property of piezoelectric materials is of great significance to improve the overall performance of electro-mechanical *** in this work,we propose a thermal annealing and high temperature poling approach to achieve significantly enhanced piezoelectricity in Pb(In_(1/2)Nb_(1/2))O_(3)single bondPb(Mg_(1/3)Nb_(2/3))O_(3)single bondPbTiO_(3)(PIN-PMN-PT)crystals with a morphotropic phase boundary(MPB)*** main idea of our approach is to realize a more sufficiently polarized crystal via active manipulation of defects and orientation of defect *** of defect dipoles by the high temperature poling is proved by the piezo-response force ***,a d_(33)of 3300 pC/N and a SE of 0.25%are obtained,nearly 60%higher than that of conventionally poled ***,such a boosting of piezoelectric property is obtained under a maintained Curie *** research not only reveals the active control of defect dipole via modified poling method in the PIN-PMN-PT crystal,but also provides a feasible strategy to further improve the property of piezoelectric materials.

关键词： Piezoelectric property Relaxor ferroelectric single crystals Defects Defect polarization

Molybdenum and tungsten chalcogenides for lithium/sodium-ion batteries: Beyond MoS2

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2019年第6期28卷 100-124页

作者： Junda Huang Zengxi wei Jiaqin liao wei Ni Caiyun Wang Jianmin Ma School of Physics and Electronics Hunan UniversityChangsha 4 J0082HunanChina Faculty of Technology University of OuluOulu 90014Finland Panzhihua University Panzhihua 617000SichuanChina ARC Centre of Excellence for Electromaterials Science Intelligent Polymer Research InstituteAIIM FacilityUniversity of WollongongNorth WollongongNSW 2500Australia Institute of Advanced Electrochemical Energy Xi'an University of TechnologyXi'an 710048ShaanxiChina

Molybdenum and tungsten chalcogenides have attracted tremendous attention in energy storage and conversion due to their outstanding physicochemical and electrochemical *** are intensive studies on molybdenum and tungsten chalcogenides for energy storage and conversion,however,there is no systematic review on the applications of WS2,Mo Se2and WSe2as anode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs),except Mo *** the importance of these contents,it is extremely necessary to overview the recent development of novel layered WS2,Mo Se2and WSe2beyond Mo S2in energy ***,we will systematically overview the recent progress of WS2,Mo Se2and WSe2as anode materials in LIBs and *** review will also discuss the opportunities,and perspectives of these materials in the energy storage fields.

关键词： MoSe2 WS2 WSe2 Lithium-ion batteries Sodium-ion batteries

Appraising the potential of calcium sulfoaluminate cement-based grouts in simulated permafrost environments

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2023年第5期17卷 722-731页

作者： Jian ZHAO Guangping HUANG Lin liao wei Victor LIU Department of Civil and Environmental Engineering University of AlbertaEdmonton T6G 1H9Canada College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China

The aim of this study is to appraise the potential of calcium sulfoaluminate(CSA)cement-based grouts in simulated permafrost *** hydration and performance of CSA cement-based grouts cured in cold environments(10,0,and−10℃)are investigated using a combination of tests,including temperature recording,X-ray diffraction(XRD)tests,thermogravimetric analysis(TGA),and unconfined compressive strength(UCS)*** recorded temperature shows a rapid increase in temperature at the early stage in all the ***,results of the TGA and XRD tests show the generation of a significant quantity of hydration products,which indicates the rapid hydration of CSA cement-based grouts at the early stage at low ***,the CSA cement-based grouts exhibit remarkably high early *** UCS values of the samples cured for 2 h at−10,0,and 10℃ are 6.5,12.0,and 12.3 MPa,*** UCS of the grouts cured at−10,0,and 10℃ increases continuously with age and ultimately reached 14.9,19.0,and 30.6 MPa at 28 d,*** findings show that the strength of grouts fabricated using CSA cement can develop rapidly in cold environments,thus rendering them promising for permafrost applications.

关键词： permafrost low temperatures calcium sulfoaluminate cement-based grouts hydration reaction compressive strength

A facile method to fabricate high-quality perovskite nanocrystals based on single crystal powder

在线全文

学校读者我要写书评

暂无评论

Nano Research 2019年第10期12卷 2640-2645页

作者： Jin-Feng liao Yi-xin Chen Jun-Hua wei Ya-Ting Cai Xu-Dong Wang Yang-Fan Xu Dai-Bin Kuang MOE Key Laboratory of Bioinorganic and Synthetic Chemistry Lehn Institute of Functional MaterialsSchool of ChemistrySun Yat-sen UniversityGuangzhou 510275China

Although great advancements have been successfully achieved in ligand-assisted reprecipitation strategy(LARP)towards lead halide perovskite nano crystals(NCs)syn thesis,it still remains challe nging to develop bright and stable iodide-based perovskite NC via facile ***,striki ngly bright MAPbl3 NCs with photoluminesce nee qua ntum yield(PLQY)as high as 79%are synthesized via replacing the raw material(MAI and Pbh)with MAPbl3 crystal powder during LARP *** has been found that crystal powder derived MAPbl3 NCs are more iodide-rich compared with that based on raw material,which is favorable to passivate the surface trap ***,femtosecond transient absorption spectroscopies and space charge limited current measurements have corroborated that the trap density is much less in crystal powder resulted MAPbl3 *** analyses indicate stronger solvation with reduced precursor colloid size has been observed in crystal powder derived precursor solution probably due to the formation of *** work has provided a facile but valid method to enhance the photoluminesce nee of perovskite NC via modulati ng the beginning precursor solution.

关键词： MAPbh nanocrystal perovskite transient absorption light emitting

Imaging internal density structure of the Laoheishan volcanic cone with cosmic ray muon radiography

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2022年第7期33卷 115-124页

作者： Ya-Ping Cheng Ran Han Zhi-wei Li Jing-Tai Li xin Mao Wen-Qiang Dou xin-Zhuo Feng Xiao-Ping Ou-Yang Bin liao Fang Liu Lei Huang Science and Technology on Reliability and Environmental Engineering Laboratory Beijing Institute of Spacecraft Environment EngineeringBeijing100094China School of Nuclear Science and Engineering North China Electric Power University2 BeiNong RoadBeijing102206China College of nuclear science and technology Beijing Normal University19 Xinjiekou outer St.Beijing100875China Aerospace Information Research Institute Chinese Academy of Sciences9 Dengzhuang South RoadBeijing100094China

Muon radiography is a promising technique for imaging the internal density structures of targets such as tunnels,pyramids,and volcanoes up to a scale of a few hundred meters by measuring the flux attenuation of cosmic ray muons after they have traveled through these *** this study,we conducted experimental muon radiography of one of the volcanoes in the Wudalianchi area in Northeast China to image its internal density *** muon detector used in this study was composed of plastic scintillators and silicon *** approximately one and a half months of observing the crater and conduit of the Laoheishan volcano cone in Wudalianchi from September 23^(rd) to November 10^(th) 2019,more than 3 million muon tracks fulfilling the data selection criteria were *** on the muon samples and high-resolution topography obtained through aerial photogrammetry using an unmanned aerial vehicle,a density image of the Laoheishan volcano cone was *** results obtained in this experiment demonstrate the feasibility of using a radiography technique based on plastic scintillator *** obtain the density distribution,we performed a detailed background analysis and found that low-energy charged particles dominated the background *** higher densities were found near the surface of the volcanic cone,whereas relatively lower densities were found near the center of the volcanic *** experiment in this study is the first volcano muon tomography study performed in *** work provides an important reference for future research.

关键词： Muon radiography Muon transmission imaging Density