检索结果-南通市图书馆

Alpine grassland degradation intensifies the burrowing behavior of small mammals:evidence for a negative feedback loop

引用

Integrative Zoology 2024年第2期19卷 240-252页

作者： Zaiwei WANG Jiawen YAN Amy MARTIN Dianne HBRUNTON Jiapeng QU Jin-Sheng He Weihong JI Zhibiao NAN State Key Laboratory of herbage Improvement and Grassland Agro-Ecosystems College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhouChina Manaaki Whenua-Landcare Research LincolnNew Zealand School of Natural Sciences Massey University(Albany Campus)AucklandNew Zealand Key Laboratory of Adaptation and Evolution of Plateau Biota Northwest Institute of Plateau BiologyChinese Academy of SciencesXiningChina Qinghai Haibei National Field Research Station of Alpine Grassland Ecosystem Northwest Institute of Plateau BiologyChinese Academy of SciencesXiningChina Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijingChina

Globally,grassland degradation is an acute ecological problem.In alpine grassland on the Tibetan Plateau,increased densities of various small mammals in degraded grassland are assumed to intensify the degradation process and these mammals are subject to lethal control.However,whether the negative impact of small mammals is solely a result of population size or also a result of activity and behavior has not been tested.In this study,we use plateau pika as a model to compare population size,core area of colony,and the number of burrow entrances and latrines between lightly and severely degraded grassland.We test whether the alleged contribution of pika to grassland degradation is a result of increased population size or increased burrowing activities of individuals in response to lower food abundance.We found that grassland degradation resulted in lower plant species richness,plant height,and biomass.Furthermore,the overall population size of pika was not significantly affected by location in lightly and severely degraded grassland.However,pika core areas in severely grassland degradation were significantly larger and had significantly higher densities of burrows and latrines.Our study provides convincing evidence that habitat-induced changes in the behavior of small,burrowing mammals,such as pika,can exacerbate grassland degradation.This finding has significant implications for managing small mammals and restoring degraded grassland ecosystems.

关键词： burrowing behavior grassland degradation plateau pika population size small mammals

来源：

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

Hydraulic directional valve fault diagnosis using a weighted adaptive fusion of multi-dimensional features of a multi-sensor

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第4期23卷 257-271页

作者： jin-chuan SHI Yan REN he-sheng TANG Jia-wei XIANG College of Mechanical and Electrical Engineering Wenzhou UniversityWenzhou325035China

Because the hydraulic directional valve usually works in a bad working environment and is disturbed by multi-factor noise,the traditional single sensor monitoring technology is difficult to use for an accurate diagnosis of it.Therefore,a fault diagnosis method based on multi-sensor information fusion is proposed in this paper to reduce the inaccuracy and uncertainty of traditional single sensor information diagnosis technology and to realize accurate monitoring for the location or diagnosis of early faults in such valves in noisy environments.Firstly,the statistical features of signals collected by the multi-sensor are extracted and the depth features are obtained by a convolutional neural network(CNN)to form a complete and stable multi-dimensional feature set.Secondly,to obtain a weighted multi-dimensional feature set,the multi-dimensional feature sets of similar sensors are combined,and the entropy weight method is used to weight these features to reduce the interference of insensitive features.Finally,the attention mechanism is introduced to improve the dual-channel CNN,which is used to adaptively fuse the weighted multi-dimensional feature sets of heterogeneous sensors,to flexibly select heterogeneous sensor information so as to achieve an accurate diagnosis.Experimental results show that the weighted multi-dimensional feature set obtained by the proposed method has a high fault-representation ability and low information redundancy.It can diagnose simultaneously internal wear faults of the hydraulic directional valve and electromagnetic faults of actuators that are difficult to diagnose by traditional methods.This proposed method can achieve high fault-diagnosis accuracy under severe working conditions.

关键词： Hydraulic directional valve Internal fault diagnosis Weighted multi-dimensional features Multi-sensor information fusion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Structural optimization and design of purging plug for improving its service performance

引用

Journal of Iron and Steel Research(International) 2022年第4期29卷 628-635页

作者： Fang-guan Tan sheng-li jin Zhu he Ya-wei Li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina National-Provincial Joint Engineering Research Center of High Temperature Materials and Lining Technology Wuhan University of Science and TechnologyWuhan 430081HubeiChina Chair of Ceramics Montanuniversitaet LeobenLeoben 8700Austria

Purging plug with slits is widely used in the secondary refining process,and its service life determines the downtime and production efficiency.To achieve a good performance in service life,optimizing the geometric structure of the slit,which can alleviate the stress concentration around the slit,was employed using the finite plate model.Furthermore,the performance of the purging plugs with different shapes of slits in the refining effect was investigated by conducting the water model experiments.The numerical simulation results showed that the appropriate shapes of slits could alleviate the stress concentration phenomena.In the water model experiment,the mixing time of the purging plug with circular slits is lesser than that of the purging plug with rectangular slits when the gas flow is less than 6.02 L/min.Compared with the rectangular slits,the circular slits are detrimental to smaller and well-distributed bubbles.Thus,the inclusion removal rate of the purging plug with circular slits is approximately 10%larger than that of the purging plug with the rectangular slits.

关键词： Purging plug Stress concentration Water model experiment Mixing time Inclusion removal Ladle metallurgy

来源：

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

Carbon fluxes and soil carbon dynamics along a gradient of biogeomorphic succession in alpine wetlands of Tibetan Plateau

引用

Fundamental Research 2023年第2期3卷 151-159页

作者： Hao Wang Lingfei Yu Litong Chen Zhenhua Zhang Xuefei Li Naishen Liang Changhui Peng Jin-Sheng He State Key Laboratory of herbage Improvement and Grassland Agro-ecosystems College of EcologyLanzhou UniversityLanzhou 730000China Institute of Ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China Qinghai Haibei National Field Research Station of Alpine Grassland Ecosystem and Key Laboratory of Adaptation and Evolution of Plateau BiotaNorthwest Institute of Plateau BiologyChinese Academy of SciencesXining 810008China Institute for Atmospheric and Earth System Research(INAR)/Physics Faculty of ScienceUniversity of HelsinkiP.O.Box 68Helsinki FI-00014Finland Earth System Division National Institute for Environmental StudiesTsukubaIbaraki 305-8506Japan g Department of Biology Sciences Institute of Environment SciencesUniversity of Quebec at MontrealMontrealQC H3C 3P8Canada State Key Laboratory of herbage Improvement and Grassland Agro-ecosystems College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou 730000China

Hydrological changes under climate warming drive the biogeomorphic succession of wetlands and may trigger substantial carbon loss from the carbon-rich ecosystems.Although many studies have explored the responses of wetland carbon emissions to short-term hydrological change,it remains poorly understood how the carbon cycle evolves with hydrology-driven wetland succession.here,we used a space-for-time approach across hydrological gradients on the Tibetan Plateau to examine the dynamics of ecosystem carbon fluxes(carbon dioxide(CO_(2))and methane(CH4))and soil organic carbon pools during alpine wetland succession.We found that the succession from mesic meadow to fen changed the seasonality of both CO_(2) and CH4 fluxes,which was related to the shift in plant community composition,enhanced regulation of soil hydrology and increasing contribution of spring-thaw emission.The paludification caused a switch from net uptake of gaseous carbon to net release on an annual timescale but produced a large accumulation of soil organic carbon.We attempted to attribute the paradox between evidence from the carbon fluxes and pools to the lateral carbon input and the systematic changes of historical climate,given that the wetlands are spatially low-lying with strong temporal climate-carbon cycle interactions.These findings demonstrate a systematic change in the carbon cycle with succession and suggest that biogeomorphic succession and lateral carbon flows are both important for understanding the long-term dynamics of wetland carbon footprints.

关键词： Carbon dioxide Methane Soil organic carbon Climate change Hydrological change

来源：

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

Improving the anti-collapse performance of water-based drilling fluids of Xinjiang Oilfield using hydrophobically modified silica nanoparticles with cationic surfactants

引用

Petroleum Science 2023年第3期20卷 1768-1778页

作者： he Li Xian-Bin Huang jin-sheng Sun Kai-he Lv Xu Meng Zhen Zhang Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China) Ministry of Education)Qingdao266580ShandongPR China School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongPR China PetroChina Tarim Oilfield Company Korla841000XinjiangPR China

Wellbore instability,especially drilling with water-based drilling fluids(WBDFs)in complex shale for-mations,is a critical challenge for oil and gas development.The purpose of this paper is to study the feasibility of using hydrophobically modified silica nanoparticle(HMN)to enhance the comprehensive performance of WBDFs in the Xinjiang Oilfield,especially the anti-collapse performance.The effect of HMN on the overall performance of WBDFs in the Xinjiang Oilfield,including inhibition,plugging,lu-bricity,rheology,and filtration loss,was studied with a series of experiments.The mechanism of HMN action was studied by analyzing the changes of shale surface structure and chemical groups,wettability,and capillary force.The experimental results showed that HMN could improve the performance of WBDFs in the Xinjiang Oilfeld to inhibit the hydration swelling and dispersion of shale.The plugging and lubrication performance of the WBDFs in the Xinjiang Oilfield were also enhanced with HMN based on the experimental results.HMN had less impact on the rheological and filtration performance of the WBDFs in the Xinjiang Oilfield.In addition,HMN significantly prevented the decrease of shale strength.The potential mechanism of HMN was as follows.The chemical composition and structure of the shale surface were altered due to the adsorption of HMN driven by electrostatic attraction.Changes of the shale surface resulted in significant wettability transition.The capillary force of the shale was converted from a driving force of water into the interior to a resistance.In summary,hydrophobic nanoparticles presented afavorable application potential for WBDFs.

关键词： Hydrophobic nanoparticle Wetting alteration Wellbore stability Water-based drilling fluids Shale

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Lowered water table causes species substitution while nitrogen amendment causes species loss in alpine wetland microbial communities

引用

Pedosphere 2021年第6期31卷 912-922页

作者： Yuntao LI Jin-Sheng He Hao WANG Jizhong ZHOU Yunfeng YANG Haiyan CHU State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of Sciences71 East Beijing RoadNanjing 210008(China) University of Chinese Academy of Sciences Beijing 100049(China) Department of Ecology College of Urban and Environmental SciencesPeking UniversityBeijing 100871(China) State Key Laboratory of Grassland Agro-Ecosystems College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou 730000(China) State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084(China) Institute for Environmental Genomics Department of Microbiology and Plant Biology and School of Civil Engineering and Environmental SciencesUniversity of OklahomaNorman OK 73019(USA) Earth Science Division Lawrence Berkeley National LaboratoryBerkeley CA 94270(USA)

Alpine wetlands are hotspots of carbon(C)storage and methane emission,and they could be key contributors to global warming.In recent years,rapid warming has lowered the water table in alpine wetlands on the Tibetan Plateau,concurrent with intensified nitrogen(N)deposition via anthropogenic activities.We carried out a field experiment to investigate the ecological impacts of these two factors on soil bacterial and functional communities,which are essential drivers of greenhouse gas emissions.Nitrogen amendment alone decreased the phylogenetic alpha-diversity of bacterial communities which could be offset by lowered water table.In contrast,microbial functional alpha-diversity,revealed by a high-throughput microarray,remained unchanged.Both bacterial and functional beta-diversity responded to lowered water table,but only bacterial community responded to N amendment.The alpha-Proteobacteria,beta-Proteobacteria,and Bacteroidetes were the major responsive bacterial lineages,and C degradation,methanogenesis,alkaline shock,and phosphorus oxidation were the major responsive functional processes.Partitioning analysis revealed that N amendment changed bacterial community structure mainly via species loss processes but did not affect bacterial functional communities,with soil pH and ammonium as the key factors influencing changes in bacterial community structure.Conversely,lowered water table altered bacterial and functional communities through species substitution processes linked to soil pH and soil moisture.According to our results,the response mechanisms of microbial communities to lowered water table and N amendment are fundamentally different in alpine wetlands.

关键词： alpha-diversity bacterial community beta-diversity microbial functional community N amendment water table lowering

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Development and simulation of a gridded thermionic cathode electron gun for a high-energy photon source

引用

Nuclear Science and Techniques 2023年第3期34卷 73-81页

作者： sheng-Chang Wang Da-Yong he Cai Meng jing-Yi Li Zu-sheng Zhou jin-Dong Liu Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

A gridded thermionic cathode electron gun was developed for the linear accelerator of the High Energy Photon Source(hePS).An electron gun should provide a large maximum bunch charge with a wide adjustable range.To satisfy these requirements,the shape of the electrode was optimized using a multi-objective genetic algorithm.A large bunch charge with an adjustable range was achieved using the grid-limited gun,the flow of which was analyzed using 3-D simulations.The electron gun has been manufactured and tested,and the measured data of the grid-limited current and simulation results are compared and discussed in this study.

关键词： Electron gun Multi-objective genetic algorithm Grid CST

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A novel multiscale simulation framework for low-dimensional memristors

引用

Science China(Physics,Mechanics & Astronomy) 2023年第7期66卷 79-87页

作者： Shurong Pan Li Liu Qijun Huang jin he Hao Wang sheng Chang Key Laboratory of Artificial Micro-and Nano-Structures of Ministry of Education School of Physics and TechnologyWuhan UniversityWuhan 430072China School of Microelectronics Wuhan UniversityWuhan 430072China

In recent years,the memristor has been widely considered an emerging device,but it has rarely been simulated.An obstacle is the change in the intrinsic atomic level when it works.Using the density functional theory(DFT),this atomic level change in structure cannot be demonstrated.Using molecular dynamics(MD),memristor electronic transport properties cannot be calculated.In this study,we propose a novel multiscale simulation framework merging MD,DFT,and the nonequilibrium Green’s function method,which can reveal not only a memristor’s basic working mechanism but also its transport character.To verify our framework’s availability in guiding innovative memristor design,a new type of memristor,a planar monolayer MoS_(2)-based memristor,is simulated for the first time.The popped S atoms’effect on its carrier transport is revealed,which clarifies the working mechanism of the planar monolayer MoS_(2)-based memory device.We hope that this framework can shed light on the analysis and design of low-dimensional memristors.

关键词： multiscale framework memristor planar monolayer transport properties MoS_(2)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A general quantum minimum searching algorithm with high success rate and its implementation

引用

Science China(Physics,Mechanics & Astronomy) 2023年第4期66卷 49-60页

作者： Yi Zeng Ziming Dong Hao Wang jin he Qijun Huang sheng Chang School of Physics and Technology Wuhan UniversityWuhan 430072China Key Laboratory of Artificial Micro-and Nano-Structures of Ministry of Education Wuhan UniversityWuhan 430072China

Finding a minimum is a fundamental calculation in many quantum algorithms.However,challenges are faced in demonstrating it effectively in real quantum computers.In practice,the number of solutions is unknown,and there is no universal encoding method.Besides that,current quantum computers have limited resources.To alleviate these problems,this paper proposes a general quantum minimum searching algorithm.An adaptive estimation method is adopted to calculate the number of solutions,and a quantum encoding circuit for arbitrary databases is presented for the first time,which improves the universality of the algorithm and helps it achieve a nearly 100%success rate in a series of random databases.Moreover,gate complexity is reduced by our simplified Oracle,and the realizability of the algorithm is verified on a superconducting quantum computer.Our algorithm can serve as a subroutine for various quantum algorithms to promote their implementation in the Noisy IntermediateScale Quantum era.

关键词： quantum minimum searching algorithm quantum circuit superconducting quantum computer quantum encoding

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Guijiajiao(Colla Carapacis et Plastri,CCP)prevents male infertility via gut microbiota modulation

引用

Chinese Journal of Natural Medicines 2023年第6期21卷 403-410页

作者： sheng Wen XU Wenjing DING jin LU Baowei LIU Lumei he Qinghu ZHOU Qing College of Traditional Chinese Medicine Hunan University of Chinese MedicineChangsha 410000China Andrology Laboratory Hunan University of Chinese MedicineChangsha 410000China Department of Dermatology The First Affiliated Hospital of Hunan University of Chinese MedicineChangsha 410000China Department of Andrology Affiliated Bao'an Hospital of Traditional Chinese MedicineThe Seventh Clinical Medical CollegeGuangzhou University of Traditional Chinese MedicineShenzhen 518000 College of Integrated Traditional Chinese and Western Medicine Hunan University of Chinese MedicineChangsha 410000 College of Traditional Chinese Medicine Hunan University of MedicineChangsha 410000 Department of Andrology The First Hospital of Hunan University of Chinese MedicineChangsha 410000

Male infertility is a significant cause of psychosocial and marital distress in approximately 50% of couples who are unable to conceive,with male factors being the underlying cause.Guijiajiao(Colla Carapacis et Plastri,CCP)is a Traditional Chinese Medicine commonly used to treat male infertility.The present study aimed to investigate the potential mechanisms underlying the preventive effects of CCP on male infertility.An infertile male rat model was established using cyclophosphamide(CTX),and CCP was administered for both treatment and prevention.Fecal microbiota transplantation(FMT)was also performed to explore the role of gut microbiota in the CCP-mediated prevention of male infertility in rats.Sperm motility and concentration were determined using a semiautomatic sperm classification analyzer.Subsequently,histopathological analysis using he staining was performed to examine the changes in the small intestine and testis.Moreover,the serum levels of lipopolysaccharide(LPS)and testosterone were measured by ELISA.In addition,immunohistochemistry was conducted to detect CD3 expression in the small intestine,while RT-qPCR was employed to assess the expressions of interleukin-1 beta(IL-1β),cluster of differentiation 3(CD3),Monocyte chemoattractant protein-1(MCP-1),and C-X-C motif chemokine ligand 10(CXCL-10)in the small intestine and epididymis.Finally,gut microbiota was analyzed by 16S rRNA sequencing.CCP improved sperm motility,number,and concentration in CTX-induced infertile male rats.CCP increased the serum testosterone level,inhibited the immune cell infiltration of the intestinal lamina propria,and promoted the aggregation of CD3+T cells in CTX-induced male infertility rats.CCP also inhibited the expressions of MCP-1,CXCL-10,and IL-1βin the epididymis of male infertility rats.At the genus level,CTX led to a reduction in the abundance of Lactobacillus,Clostridia_UCG.014,and Romboutsia in the intestinal tract of rats.In contrast,CCP decreased the abundance of Ruminococcus and increased the abundance of Romboutsi

关键词： Colla Carapacis et Plastri Fecal microbiota transplantation Male infertility Gut microbiota Spermatogenesis ability

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：