检索结果-南通市图书馆

Intraspecific floral colour variation in three Pedicularis species

Plant Diversity 2024年第2期46卷 274-279页

作者： Qiu-Yu Zhang Zhe chen hang Sun Yang Niu State Key Laboratory of Plant Diversity and Specialty Crops Kunming Institute of BotanyChinese Academy of SciencesKunming 650201YunnanChina University of Chinese Academy of Sciences Beijing 100049China

Flower constancy describes the phenomenon that pollinators tend to successively visit flowers of a single species during foraging,reducing reproductive interference in natural communities.The extent of flower constancy is largely determined by the floral traits of co-flowering species.Both higher inter-specific and lower intraspecific differences of floral traits should contribute to a higher level of flower constancy.However,previous studies mainly focused on interspecific difference,and the intraspecific variation(consistency)of floral traits received much less attention.We hypothesise that selection may favour lower intraspecific floral trait variation in communities composed of multiple co-flowering congeners.We investigated the floral colour variation of three focal Pedicularis species that share pollinators in 19communities composed of either single or multiple Pedicularis species.Colour was quantified using image-based colour analysis as perceived by pollinators.We found that most of the intrapopulation floral colour variation was below the colour discrimination threshold of bumblebees,implying strongly constrained by the visual selection by pollinators.Contrary to the hypothesis,there is no significant difference in intraspecific floral colour variation between different community contexts.It may be due to the relatively large interspecific floral colour differences of most co-flowering species.The influence of community context on intraspecific variation may be reflected in floral traits other than colours.

关键词： Flower constancy Floral colour variation Plantepollinator interactions Pollinator vision

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

Sex-specific facilitation and reproduction of the gynodioecious cushion plant Arenaria polytrichoides on the Himalaya-Hengduan mountains,SW China

引用

Plant Diversity 2024年第2期46卷 247-255页

作者： Xufang chen Yazhou Zhang Lishen Qian Renyu Zhou hang Sun Jianguo chen State Key Laboratory of Plant Diversity and Specialty Crops Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnanChina Yunnan Key Laboratory of Plateau Wetland Conservation Restoration and Ecological ServicesSouthwest Forestry UniversityKunmingYunnanChina

When benefiting other beneficiaries,cushion plants may reciprocally receive feedback effects.The feedback effects on different sex morphs,however,remains unclear.In this study,taking the gynodioecious Arenaria polytrichiodes as a model species,we aimed to assess the sex-specific facilitation intensity of cushion plant by measuring the beneficiary cover ratio,and to assess the potential costs in cushion reproductive functions by measuring the flower and fruit cover ratios.The total beneficiary cover ratio was similar between females and hermaphrodites.Females produced much less flowers but more fruits than hermaphrodites.These results suggested that females and hermaphrodites possess similar facilitation intensity,and female cushion A.polytrichoides may allocate more resources saved from pollen production to seed production,while hermaphrodites possibly allocate more resources to pollen production hence reducing seed production.The surface areas covered by beneficiaries produced less flowers and fruits than areas without beneficiaries.In addition,strong negative correlations between beneficiary cover and flower cover were detected for both females and hermaphrodites,but the correlation strength were similar for these two sex morphs.However,the correlation between beneficiary cover and fruit cover was only significantly negative for females,suggesting that beneficiary plants negatively affect fruit reproduction of females while have neutral effects on hermaphrodites.All the results suggest that to facilitate other beneficiaries can induce reproductive costs on cushion A.polytrichoides,with females possibly suffering greater cost than hermaphrodites.Such differentiation in reproductive costs between sex morphs,in long-term perspective,may imply sex imbalance in population dynamics.

关键词： Facilitation intensity Feedback effect Sex-specific facilitation Nurse plant Population dynamics Reproductive function

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 of underwater electric manipulator based on interventional autonomous underwater vehicle (AUV)

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第3期25卷 238-250页

作者： Xiaohui HU Jiawang chen hang ZHOU Ziqiang REN Ocean cllege Zhejiang UniversityZhoushan 316021China Hainan Institute Zhejiang UniversitySanya 572025China The Engineering Research Center of Oceanic Sensing Technology and Equipment Ministry of EducationZhoushan 316021China

In applications such as marine rescue,marine science,archaeology,and offshore industries,autonomous underwater vehicles(AUVs)are frequently used for survey missions and monitoring tasks,with most operations being performed by manned submersibles or remotely operated vehicles(ROVs)equipped with robotic arms,as they can be operated remotely for days without problems.However,they require expensive marine vessels and specialist pilots to operate them.Scientists exploring oceans are no longer satisfied with the use of manned submersibles and ROVs.There is a growing desire for seabed exploration to be performed using smarter,more flexible,and automated equipment.By improving the field operation and intervention capability of AUVs,large-scale and long-range seafloor exploration and sampling can be performed without the support of a mother ship,making it a more effective,economical,convenient,and rapid means of seafloor exploration and sampling operations,and playing a critical role in marine resource exploration.In this study,we explored the integration technology of underwater electric robotic arms and AUVs and designed a new set of electric manipulators suitable for water depths greater than 500 m.The reliability of the key components was analyzed by finite element analysis and,based on the theory of robot kinematics and dynamics,simulations were performed to verify the reliability of the key components.Experiments were conducted on land and underwater,trajectory tracking experiments were completed,and the experimental data in air and water were compared and analyzed.Finally,the objectives for further research on the autonomous control of the manipulator underwater were proposed.

关键词： Underwater electric manipulator Inverse kinematics Trajectory planning Trajectory tracking accuracy

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

Price Masking Strategy of Cross-Border E-Commerce Platform Financing

引用

Journal of Systems Science & Complexity 2024年第2期37卷 668-691页

作者： LI Jianbin hang Zhouxin chen Zhiyuan XIAO Shan School of Management Huazhong University of Science and TechnologyWuhan 430074China School of Economics and Management Wuhan UniversityWuhan 430072China

E-commerce platform financing is a new service pattern of supply chain finance.However,this pattern may bring some new issues when considering the problem of cash flow shortage and financing difficulties of small and medium-sized enterprises.When enterprises use this service,they worry about the leakage of preferential wholesale price when applying the full loan amount and providing the true transaction information.Based on the model consisting of a supplier,a retailer and a cross-border e-commerce platform,the authors design a price masking strategy to prevent the retailer’s preferential wholesale price information from leakage.The authors analyze the profit of the retailer and the platform before and after adopting the price masking strategy.The authors find that the price masking strategy always benefits the retailer.Besides,the optimal profit of the retailer and the platform are both affected by the loan interest rate.Moreover,there exists a range of loan interest rates that can benefit both the retailer and the platform if the price masking strategy is adopted.The research emphasizes that platform can expand the total business volume by allowing retailers to use price masking strategy.In other words,there will be more and more retailers attracted by the strategy,which benefits the long-term growth of cross-border e-commerce platform financing.

关键词： Cross-border e-commerce e-commerce platform financing price masking supply chain finance

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

Supporting-electrolyte-free electrochemical[2+2+1]annulation of benzo[d]isothiazole 1,1-dioxides,N-arylglycines and paraformaldehyde

引用

Chinese Chemical Letters 2024年第6期35卷 327-330页

作者： Hai-Yang Song jun Jiang Yu-hang Song Min-hang Zhou Chao Wu Xiang chen Wei-Min He School of Chemistry and Chemical Engineering University of South ChinaHengyang 421001China

The H-bond promoted electrochemical[2+2+1]annulation of benzo[d]isothiazole 1,1-dioxides,Narylglycines and paraformaldehyde for the synthesis of various benzo[d]imidazo[1,5-b]isothiazole 5,5-dioxide derivatives under ... 详细信息

关键词： H-bond N-Arylglycines Paraformaldehyde Organic electro-synthesis Electrolyte-free

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

The recirculation flow after different cross-section shaped high-rise buildings with applications to ventilation assessment and drag parameterization

引用

Building Simulation 2024年第4期17卷 509-524页

作者： Keyi chen Ziwei Mo Jian hang School of Atmospheric Sciences Sun Yat-sen University&Southern Marine Science and Engineering Guangdong LaboratoryZhuhai519082China Key Laboratory of Tropical Atmosphere-Ocean System Ministry of EducationZhuhai519000China

The building cross-section shape significantly affects the flow characteristics around buildings,especially the recirculation region behind the high-rise building.Eight generic building shapes including square,triangle,octagon,T-shaped,cross-shaped,#-shaped,H-shaped and L-shaped are examined to elucidate their effects on the flow patterns,recirculation length L and areas A using computational fluid dynamics(CFD)simulations with Reynolds-averaged Navier-Stokes(RANS)approach.The sizes and positions of the vortexes behind the buildings are found to be substantially affected by the building shapes and subsequently changing the recirculation flows.The recirculation length L is in the range of 1.6b-2.6b with an average of 2b.The maximum L is found for L-shaped building(2.6b)while the shortest behind octagon building(1.6b).The vertical recirculation area Av is in the range of 1.5b^(2)-3.2b^(2)and horizontal area Ah in 0.9b^(2)-2.2b^(2).The L,Av and Ah generally increase with increasing approaching frontal area when the wind direction changes but subject to the dent structures of the#-shaped and cross-shaped buildings.The area-averaged wind velocity ratio(AVR),which is proposed to assess the ventilation performance,is in the range of 0.05 and 0.14,which is around a three-fold difference among the different building shapes.The drag coefficient parameterized by Ah varies significantly,suggesting that previous models without accounting for building shape effect could result in large uncertainty in the drag predictions.These findings provide important reference for improving pedestrian wind environment and shed some light on refining the urban canopy parameterization by considering the building shape effect.

关键词： recirculation region cross-section shape ventilation assessment drag parameterization computational fluid dynamics

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

A Review of Contact Electrification at Diversified Interfaces and Related Applications on Triboelectric Nanogenerator

引用

Nano-Micro Letters 2024年第1期16卷 106-130页

作者： jun Hu Mitsumasa Iwamoto Xiangyu chen CAS Center for Excellence in Nanoscience Beijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 100083People’s Republic of China School of Nanoscience and Engineering University of Chinese Academy of SciencesBeijing 100049People’s Republic of China Department of Physical Electronics Tokyo Institute of Technology2‑12‑1 S3‑33 O‑OkayamaMeguro‑KuTokyo 152‑8552Japan

The triboelectric nanogenerator(TENG)can effectively collect energy based on contact electrification(CE)at diverse interfaces,including solid–solid,liquid–solid,liquid–liquid,gas–solid,and gas–liquid.This enables energy harvesting from sources such as water,wind,and sound.In this review,we provide an overview of the coexistence of electron and ion transfer in the CE process.We elucidate the diverse dominant mechanisms observed at different interfaces and emphasize the interconnectedness and complementary nature of interface studies.The review also offers a comprehensive summary of the factors influencing charge transfer and the advancements in interfacial modification techniques.Additionally,we highlight the wide range of applications stemming from the distinctive characteristics of charge transfer at various interfaces.Finally,this review elucidates the future opportunities and challenges that interface CE may encounter.We anticipate that this review can offer valuable insights for future research on interface CE and facilitate the continued development and industrialization of TENG.

关键词： Contact electrification Interfaces Triboelectric nanogenerators Diversified applications

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

Composite Converter Combined APFC with Switched-capacitor Converter

引用

CSEE Journal of Power and Energy Systems 2024年第1期10卷 281-291页

作者： Qing Fu Yishan chen Yixing Su Yang hang School of Physics Sun Yat-Sen UniversityGuangzhou 510275China

To reduce switch numbers and voltage stress in semiconductor devices,this paper proposes a novel single-phase converter combined Active Power Factor Correction(APFC)with switched-capacitor converter.In addition,dynamic voltage regulation and voltage gain are improved by integrating the boost converter and switching capacitor cells.The interstage bulk capacitor is no longer needed.An average current control with redistribution of voltage in cells is proposed to obtain voltage lift ability of the switching capacitor cells and maintain a high-power factor.To study and verify the proposed converter preliminarily,theoretical analysis and simulation are presented in the paper.Furthermore,a 50o W prototype with two different configurations is built for experimental verification.The proposed converter can reach 95.62%of maximum efficiency,0.99 of power factor,and 3.55%of THD with 600 V output voltage,simultaneously.

关键词： AC-DC converter composite conveter power factor correction switched capacitor

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

Degradation of warm permafrost and talik formation on the Qinghai-Tibet Plateau in 2006-2021

引用

Advances in Climate Change Research 2024年第2期15卷 275-284页

作者： Qi-hang MEI Ji chen You-Qian LIU Shou-Hong Zhang Jing-Yi ZHAO Tian-Chun DONG jun-cheng WANG Yao-jun ZHAO Beiluhe Observation and Research Station of Frozen Soil Engineering and Environment Key Laboratory of Cryospheric Science and Frozen Soil EngineeringNorthwest Institute of Eco-Environmental and ResourcesChinese Academy of SciencesLanzhou 730000China China Railway Qinghai-Tibet Group Co.Ltd Xining 810007China University of Chinese Academy of Sciences Beijing 100049China

Permafrost is degrading globally,particularly those with low thermal stability on the Qinghai-Tibet Plateau,owing to climate change.However,the inadequacy of direct research on permafrost degradation based on in-situ monitoring limits the prediction of permafrost degradation and engineering practices.This study explored the processes and modes of permafrost degradation into talik by analyzing ground temperature data from five points in the hinterland of the Qinghai-Tibet Plateau from 2006 to 2021.The results showed that the degradation of the warm permafrost layer with a geothermal gradient of zero occurred simultaneously in the top and bottom directions.The rate of permafrost degradation from the top down and bottom up increase during the degradation process,but the increase of the former is more drastic after the formation of thawed interlayer.Additionally,the construction of the Qinghai-Tibet Railway changed the degradation modes of the permafrost in adjacent natural sites through horizontal heat transfer,particularly after through talik formation under the embankment.The findings suggest that taking countermeasures before or immediately after forming thawed interlayer is more effective.When evaluating the thermal impact of projects in warm permafrost regions,special attention should be given to the horizontal heat transfer process that may result from the formation of a through talik.

关键词： Warm permafrost Degradation Talik Qinghai-Tibet Plateau Climate 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

Continuous preparation of strong and tough PVA nanocomposite fibers by mechanical stretching-assisted salting-out treatment

引用

Nano Research 2024年第4期17卷 3156-3163页

作者： hang chen Guangze Yang Yingzhi Sun Yichao Xu Mingjie Liu Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education School of ChemistryBeihang UniversityBeijing 100191China Research Institute for Frontier Science Beihang UniversityBeijing 100191China International Research Institute for Multidisciplinary Science Beihang UniversityBeijing 100191China

Polymer composite fibers with superior properties such as excellent combined strength and toughness and biocompatibility can be used in high-tech applications of braided protective devices and smart wearable,however the research of high-performance polymer composite fiber remains in the infant stage.Here we present a strategy to produce strong and tough anisotropic polymer nanocomposite fibers with orientedly aligned salt rods using mechanical stretching-assisted salting-out treatment.The prepared nanocomposite fibers have a tensile strength of up to 786±2.7 MPa and an elongation at break of 81%,and the anisotropic fibers exhibit good transmission of mechanical vibration in the longitudinal direction with high resolution.During the fabrication process,the salt builds up into oriented rods during the directional salting process,and the polymer is confined to the 150 nm domain between the rods after the solvent is completely evaporated,giving the nanocomposite fibers superior mechanical properties.The presented strategy can be applied to the continuous mass production of nanocomposite fibers and is also generalizable to other polymer nanocomposites,which could extend the applicability of nanocomposite fibers to conditions involving more demanding mechanical loading and mechanical vibration transmission.

关键词： poly(vinyl alcohol)(PVA)nanofibers oriented structure ultrastrong and stiff mechanical vibration transmission salting out continuous production

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：