期刊文献+
共找到4,963篇文章
< 1 2 249 >
每页显示 20 50 100
Large-Scale Multi-Objective Optimization Algorithm Based on Weighted Overlapping Grouping of Decision Variables
1
作者 Liang Chen Jingbo Zhang +2 位作者 Linjie Wu Xingjuan Cai Yubin Xu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期363-383,共21页
The large-scale multi-objective optimization algorithm(LSMOA),based on the grouping of decision variables,is an advanced method for handling high-dimensional decision variables.However,in practical problems,the intera... The large-scale multi-objective optimization algorithm(LSMOA),based on the grouping of decision variables,is an advanced method for handling high-dimensional decision variables.However,in practical problems,the interaction among decision variables is intricate,leading to large group sizes and suboptimal optimization effects;hence a large-scale multi-objective optimization algorithm based on weighted overlapping grouping of decision variables(MOEAWOD)is proposed in this paper.Initially,the decision variables are perturbed and categorized into convergence and diversity variables;subsequently,the convergence variables are subdivided into groups based on the interactions among different decision variables.If the size of a group surpasses the set threshold,that group undergoes a process of weighting and overlapping grouping.Specifically,the interaction strength is evaluated based on the interaction frequency and number of objectives among various decision variables.The decision variable with the highest interaction in the group is identified and disregarded,and the remaining variables are then reclassified into subgroups.Finally,the decision variable with the strongest interaction is added to each subgroup.MOEAWOD minimizes the interactivity between different groups and maximizes the interactivity of decision variables within groups,which contributed to the optimized direction of convergence and diversity exploration with different groups.MOEAWOD was subjected to testing on 18 benchmark large-scale optimization problems,and the experimental results demonstrate the effectiveness of our methods.Compared with the other algorithms,our method is still at an advantage. 展开更多
关键词 Decision variable grouping large-scale multi-objective optimization algorithms weighted overlapping grouping direction-guided evolution
下载PDF
Introducing hydroxyl groups to tailor the d-band center of Ir atom through side anchoring for boosted ORR and HER
2
作者 Qing Lv Meiping Li +3 位作者 Xiaodong Li Xingru Yan Zhufeng Hou Changshui Huang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第3期144-151,I0005,共9页
Tuning the coordination atoms of central metal is an effective means to improve the electrocatalytic activity of atomic catalysts.Herein,iridium(Ir) is proposed to be asymmetrically anchored by sp-N and pyridinic N of... Tuning the coordination atoms of central metal is an effective means to improve the electrocatalytic activity of atomic catalysts.Herein,iridium(Ir) is proposed to be asymmetrically anchored by sp-N and pyridinic N of hydrogen-substituted graphdiyne(HsGDY),and coordinated with OH as an Ir atomic catalyst(Ir_(1)-N-HsGDY).The electron structures,especially the d-band center of Ir atom,are optimized by these specific coordination atoms.Thus,the as-synthesized Ir_(1)-N-HsGDY exhibits excellent electrocatalytic performances for oxygen reduction and hydrogen evolution reactions in both acidic and alkaline media.Benefiting from the unique structure of HsGDY,IrN_(2)(OH)_(3) has been developed and demonstrated to act as the active site in these electrochemical reactions.All those indicate the fresh role of the sp-N in graphdiyne in producing a new anchor way and contributing to promote the electrocatalytic activity,showing a new strategy to design novel electrochemical catalysts. 展开更多
关键词 Oxygen reduction reaction D-band center Graphdiyne Hydroxyl group ELECTROCATALYSIS
下载PDF
End-group modulation of phenazine based non-fullerene acceptors for efficient organic solar cells with high open-circuit voltage
3
作者 Yahui Zhang Yafeng Li +7 位作者 Ruixiang Peng Yi Qiu Jingyu Shi Zhenyu Chen Jinfeng Ge Cuifen Zhang Zheng Tang Ziyi Ge 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期461-468,I0011,共9页
Phenazine-based non-fullerene acceptors(NFAs)have demonstrated great potential in improving the power conversion efficiency(PCE)of organic solar cells(OSCs).Halogenation is known to be an effective strategy for increa... Phenazine-based non-fullerene acceptors(NFAs)have demonstrated great potential in improving the power conversion efficiency(PCE)of organic solar cells(OSCs).Halogenation is known to be an effective strategy for increasing optical absorption,refining energy levels,and improving molecular packing in organic semiconductors.Herein,a series of NFAs(Pz IC-4H,Pz IC-4F,Pz IC-4Cl,Pz IC-2Br)with phenazine as the central core and with/without halogen-substituted(dicyanomethylidene)-indan-1-one(IC)as the electron-accepting end group were synthesized,and the effect of end group matched phenazine central unit on the photovoltaic performance was systematically studied.Synergetic photophysical and morphological analyses revealed that the PM6:Pz IC-4F blend involves efficient exciton dissociation,higher charge collection and transfer rates,better crystallinity,and optimal phase separation.Therefore,OSCs based on PM6:Pz IC-4F as the active layer exhibited a PCE of 16.48%with an open circuit voltage(Voc)and energy loss of 0.880 V and 0.53 e V,respectively.Accordingly,this work demonstrated a promising approach by designing phenazine-based NFAs for achieving high-performance OSCs. 展开更多
关键词 Organic solar cells Non-fullerene acceptor PHENAZINE Central core End group
下载PDF
Adaptive Event-Triggered Time-Varying Output Group Formation Containment Control of Heterogeneous Multiagent Systems
4
作者 Lihong Feng Bonan Huang +2 位作者 Jiayue Sun Qiuye Sun Xiangpeng Xie 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第6期1398-1409,共12页
In this paper,a class of time-varying output group formation containment control problem of general linear hetero-geneous multiagent systems(MASs)is investigated under directed topology.The MAS is composed of a number... In this paper,a class of time-varying output group formation containment control problem of general linear hetero-geneous multiagent systems(MASs)is investigated under directed topology.The MAS is composed of a number of tracking leaders,formation leaders and followers,where two different types of leaders are used to provide reference trajectories for movement and to achieve certain formations,respectively.Firstly,compen-sators are designed whose states are estimations of tracking lead-ers,based on which,a controller is developed for each formation leader to accomplish the expected formation.Secondly,two event-triggered compensators are proposed for each follower to evalu-ate the state and formation information of the formation leaders in the same group,respectively.Subsequently,a control protocol is designed for each follower,utilizing the output information,to guide the output towards the convex hull generated by the forma-tion leaders within the group.Next,the triggering sequence in this paper is decomposed into two sequences,and the inter-event intervals of these two triggering conditions are provided to rule out the Zeno behavior.Finally,a numerical simulation is intro-duced to confirm the validity of the proposed results. 展开更多
关键词 Adaptive control event-triggered mechanisms for-mation containment(FC) heterogeneous multiagent systems time-varying group formation.
下载PDF
Combined Promoting Effects of Specific Organic Functional Groups and Alumina Surface Characteristics for the Design of a Highly Efficient NiMo/Al_(2)O_(3) Hydrodesulfurization Catalyst
5
作者 Li Huifeng Li Mingfeng +2 位作者 Zhang Le Wang Wei Nie Hong 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2024年第1期1-11,共11页
To prepare a highly efficient NiMo/Al_(2)O_(3) hydrodesulfurization catalyst,the combined effects of specific organic functional groups and alumina surface characteristics were investigated.First,the correlation betwe... To prepare a highly efficient NiMo/Al_(2)O_(3) hydrodesulfurization catalyst,the combined effects of specific organic functional groups and alumina surface characteristics were investigated.First,the correlation between the surface characteristics of four different alumina and the existing Mo species states was established.It was found that the Mo equilibrium adsorption capacity can be used as a specific descriptor to quantitatively evaluate the changes in surface characteristics of different alumina.A lower Mo equilibrium adsorption capacity for alumina means weaker metal-support interaction and the loaded Mo species are easier to transform into MoS2.However,the Mo-O-Al bonds still exist at the metal-support interface.The introduction of cationic surfactant hecadecyl trimethyl ammonium bromide(CTAB)can further improve Mo species dispersion through electrostatic attraction with Mo anions and interaction of its alkyl chain with the alumina surface;meanwhile,the introduction of ethylenediamine tetraacetic acid(EDTA)can complex with Ni ions to enhance the Ni-promoting effect on Mo.Therefore,the NiMo catalyst designed using alumina with lower Mo equilibrium adsorption capacity and the simultaneous addition of EDTA and CTAB exhibits the highest hydrodesulfurization activity for 4,6-dimethyl dibenzothiophene because of its proper metal-support interaction and more well-dispersed Ni-Mo-S active phases. 展开更多
关键词 ALUMINA Mo equilibrium adsorption capacity organic functional groups metal-support interaction HYDRODESULFURIZATION
下载PDF
Polymetamorphism of the ultrahigh-temperature granulites in the Rauer Group,East Antarctica:new evidence from zircon SHRIMP U-Pb ages
6
作者 TONG Laixi LIU Zhao +3 位作者 LI Chao LU Junsheng YANG Wenqiang WANG Yanbin 《Advances in Polar Science》 CSCD 2024年第2期192-205,共14页
The Rauer Group is located on the eastern margin of the early Paleozoic Prydz Belt in East Antarctica,and the typical ultrahigh-temperature(UHT,>900℃)granulites outcrop on Mather Peninsula.However,the timing of UH... The Rauer Group is located on the eastern margin of the early Paleozoic Prydz Belt in East Antarctica,and the typical ultrahigh-temperature(UHT,>900℃)granulites outcrop on Mather Peninsula.However,the timing of UHT metamorphism and P–T path of the UHT granulites have long been debated,which is critical to understanding the tectonic nature and evolution history of the Prydz Belt.Thus,both a sapphirine-bearing UHT metapelitic granulite and a garnet-bearing UHT mafic granulite are selected for zircon SHRIMP U-Pb age dating.The results show that metamorphic zircon mantles yield weighted mean^(206)Pb/^(238)U ages of 918±29 Ma and 901±29 Ma for the metapelitic and mafic granulites,respectively,while zircon rims and newly grown zircons yield weighted mean^(206)Pb/^(238)U ages of 523±9 Ma and 532±11 Ma,respectively.These new zircon age data suggest that the UHT granulites may have experienced polymetamorphism,in which pre-peak prograde stage occurred in the early Neoproterozoic Grenvillian orogenesis(1000–900 Ma),whereas the UHT metamorphism occurred in the late Neoproterozoic to early Paleozoic Pan-African orogenesis(580–460 Ma).This implies that P–T path of the UHT granulites should consist of two separate high-grade metamorphic events including the Grenvillian and Pan-African events,which are supposed to be related to assembly of Rodinia and Gondwana supercontinents respectively,and hence the overprinting UHT metamorphic event may actually reflect an important intracontinental reworking. 展开更多
关键词 ultrahigh-temperature granulites zircon SHRIMP U-Pb ages POLYMETAMORPHISM Rauer group East Antarctica
下载PDF
How Group Leaders Build Stable Community Buying Groups:A Perspective Based on the Differential Mode of Association
7
作者 SI Xiang 《Psychology Research》 2024年第1期30-35,共6页
Since 2016,community group buying has grown significantly in China,largely driven by its efficient logistics,supply chains,low prices,and convenience.This model has been further popularized during the COVID-19 pandemi... Since 2016,community group buying has grown significantly in China,largely driven by its efficient logistics,supply chains,low prices,and convenience.This model has been further popularized during the COVID-19 pandemic due to its effectiveness in meeting daily needs while minimizing human-to-human contact.A key component of this business model is the“group leaders”-influential individuals within a community responsible for managing group buying activities,which include order collection,supplier liaison,and goods distribution.Their primary task is to form and sustain a reliable community group buying consortium,a task that demands excellent organizational and interpersonal skills.This paper examines this phenomenon using the lens of the differential mode of association,a theoretical model explaining interpersonal relationships in traditional Chinese society.The research indicates that group leaders,through regular interaction with consumers,are able to alter their social network position,increase their influence,understand consumer needs,provide satisfying services,and enhance trust,thereby transforming consumers into loyal group buying participants.This transformation not only brings stability to group buying activities but also reinforces the community influence of group leaders,thus fostering the growth of community group buying. 展开更多
关键词 Community group buying China group leaders The differential mode of association
下载PDF
Group Images of Korean Women on Douyin:Representation,Generation,and Identification
8
作者 JIN Yihan CHEN Lu 《Cultural and Religious Studies》 2024年第2期95-103,共9页
Since 2023,the slogan“Question Korean women,understand Korean women,learn Korean women”has become popular in Chinese social networks.Previously,Chinese netizens have not paid such attention to women from other count... Since 2023,the slogan“Question Korean women,understand Korean women,learn Korean women”has become popular in Chinese social networks.Previously,Chinese netizens have not paid such attention to women from other countries.In response to this phenomenon,this paper combines neoliberal feminist theories with thematic analysis to obtain a total of 80 valid samples from the Douyin platform to analyze the image of Korean women disseminated on the Douyin platform.Finally,it is concluded that the image of Korean women’s strict self-discipline,internal and external cultivation,sobriety of thought,and the spirit of courageous struggle have to a certain extent promoted the awakening of self-consciousness of female netizens in China;on the other hand,it is also necessary to realize that the image of Korean women disseminated in Douyin is not completely true,and it is also necessary to be alert to the phenomenon that the gender dichotomy has been reduced to the attraction of network traffic and capital as a sharp weapon. 展开更多
关键词 Douyin Korean women FEMINISM group images
下载PDF
Review on the Development of Cosmetic Industry from the Perspective of Group Standards
9
作者 Xue Wei You Weishan +1 位作者 Wu Jianghong Su Lihong 《China Detergent & Cosmetics》 CAS 2024年第1期10-19,共10页
From the perspective of group standards, the dynamics of the cosmetic industry in the past few years were briefly reviewed and analyzed, including the number of group standards published, types of group standards, gro... From the perspective of group standards, the dynamics of the cosmetic industry in the past few years were briefly reviewed and analyzed, including the number of group standards published, types of group standards, groups, and geographical distribution of the groups. The large number of participating groups and the wide range of geographical distribution indicated that group standards could play a positive role in the sustained and positive development of cosmetic industry. The future development of cosmetic industry was also prospected。 展开更多
关键词 group standard COSMETIC INDUSTRY
下载PDF
Application of Specialized Group Management in the Quality Control of Perioperative Nursing
10
作者 Cong Fu Xuefei Li +4 位作者 Li Wang Yuanyuan Jiang Xinrong Qi Chen Ding Shanshan Tang 《Journal of Clinical and Nursing Research》 2024年第2期70-75,共6页
Objective:To explore the role of specialized group management in the quality control of perioperative nursing.Methods:45 surgical nurses from our hospital were selected as the research subjects.Traditional operating r... Objective:To explore the role of specialized group management in the quality control of perioperative nursing.Methods:45 surgical nurses from our hospital were selected as the research subjects.Traditional operating room management was adopted from July 2019 to June 2020,and specialized group management was adopted from July 2020 to June 2021.The surgeon’s satisfaction,surgical nurses’core professional competence,and surgical patients’satisfaction were obtained through surveys and the results were analyzed.Results:Surgeon satisfaction before the implementation of specialized group management was significantly lower than after its implementation(P<0.05).Besides,surgical nurses’core professional competency scores before the implementation of specialized group management were significantly lower than after its implementation(P<0.05).Lastly,surgical patients’satisfaction before the implementation of specialized group management was significantly lower than after its implementation(P<0.05).Conclusion:Specialized group management helps to improve the quality of perioperative care and should be applied in clinical practice. 展开更多
关键词 Specialized group management Operating room Quality of care CONTROL
下载PDF
The Effectiveness of Group Cooperative Learning Method in Badminton Teaching in Colleges and Universities
11
作者 Jiankun Feng 《Journal of Contemporary Educational Research》 2024年第4期290-295,共6页
In college badminton teaching,teachers utilize the group cooperative learning method,which not only helps to improve students’badminton skill level but also cultivates their teamwork spirit,communication skills,and s... In college badminton teaching,teachers utilize the group cooperative learning method,which not only helps to improve students’badminton skill level but also cultivates their teamwork spirit,communication skills,and self-management ability unconsciously.In view of this,this paper mainly describes the significance of applying the group cooperative learning method in college badminton teaching,analyzes the current problems in college badminton teaching,and aims to discover effective development strategies for group cooperative learning method in college badminton teaching in order to improve the effectiveness of college badminton teaching. 展开更多
关键词 group cooperative learning method Colleges and universities Badminton teaching Effective development
下载PDF
Construction and Application of a Quality Evaluation System for Group Elderly Care Services Based on the Internet of Things
12
作者 Xiyu Yang Jialu Li Weiming Tian 《Proceedings of Business and Economic Studies》 2024年第1期155-161,共7页
With the continuous intensification of global aging,the issue of elderly care has become an increasingly prominent social problem.The Internet of Things(IoT)technology,as an emerging field,holds broad application pros... With the continuous intensification of global aging,the issue of elderly care has become an increasingly prominent social problem.The Internet of Things(IoT)technology,as an emerging field,holds broad application prospects.This article focuses on the application of IoT technology in group elderly care services and constructs a quality evaluation system for these services based on IoT technology.Through the analysis of practical application cases,the advantages and challenges of IoT technology in group elderly care services have been examined,confirming the feasibility and effectiveness of the evaluation system. 展开更多
关键词 Internet of Things group retirement Quality assessment system
下载PDF
Extension of Paraconsistent Many-Valued Similarity Method to Group Decision
13
作者 Abdulai Inusah 《Journal of Applied Mathematics and Physics》 2024年第3期944-981,共38页
The Paraconsistent Many-Valued Similarity (PMVS) method for multi-attribute decision making will be incomplete as a decision model if it is not extended to the realm of group decision-making. Therefore, in this articl... The Paraconsistent Many-Valued Similarity (PMVS) method for multi-attribute decision making will be incomplete as a decision model if it is not extended to the realm of group decision-making. Therefore, in this article, our primary objective is to show how the paraconsistent many-valued similarity method can be used to solve group decision-making problems involving choice making or ranking of a finite set of decision alternatives. Moreover, since weights are very important parameters in multi-attribute decision-making, we have introduced the Borda rule to calculate the weights of experts and that of every criterion under consideration. To demonstrate how the proposed method works, a numerical example on energy sources of an economy from the points of view of a group of experts is investigated. Further, we compare the results of this new approach with that of fuzzy TOPSIS group decision-making method to illustrate the robustness and effectiveness of the former. 展开更多
关键词 Multiple Criteria Evaluation group Decision-Making Paraconsistent Borda Rule Energy Sources Global Strength Global Weakness Aggregated Evidence Couples
下载PDF
金融机构ESG投资的“漂绿”与“反漂绿”——基于DWSGroup的案例分析
14
作者 许汉友 杨雨蝶 《财会月刊》 北大核心 2024年第8期92-98,共7页
深化绿色金融发展、助力经济绿色发展,是实现“双碳”目标的重要途径,特别是在ESG理念盛行的今天,金融机构的ESG投资行为因其深远影响而颇受投资者青睐,但层出不穷的“漂绿”现象也牢牢制约着绿色金融的发展,制约着ESG投资的发展。西方... 深化绿色金融发展、助力经济绿色发展,是实现“双碳”目标的重要途径,特别是在ESG理念盛行的今天,金融机构的ESG投资行为因其深远影响而颇受投资者青睐,但层出不穷的“漂绿”现象也牢牢制约着绿色金融的发展,制约着ESG投资的发展。西方国家作为绿色金融发展先驱,从信息披露、制度监管、实践探索等方面对“漂绿”现象进行了研究和治理。本文在学习其先进经验的基础上,基于舞弊三角理论对DWSGroup案例进行分析,从压力、机会和自我合理化因素角度对金融机构ESG投资“漂绿”行为的动因进行分析,并据此提出我国“反漂绿”体系框架,以期为绿色金融的平稳发展和“双碳”目标的实现作出贡献。 展开更多
关键词 漂绿 绿色金融 DWS group ESG投资
下载PDF
Understanding Dual-Polar Group Functionalized COFs for Accelerating Li-Ion Transport and Dendrite-Free Deposition in Lithium Metal Anodes 被引量:1
15
作者 Qi An Hong-en Wang +5 位作者 Genfu Zhao Shimin Wang Lufu Xu Han Wang Yao Fu Hong Guo 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第2期293-302,共10页
Lithium metal batteries(LMBs)have attracted wide attentions because of their high theoretical specific capacity and low electrochemical potential.However,the growth of lithium dendrites seriously affects the practical... Lithium metal batteries(LMBs)have attracted wide attentions because of their high theoretical specific capacity and low electrochemical potential.However,the growth of lithium dendrites seriously affects the practical application of LMBs.Thus,the lithium-philic carbonyl and carboxy dualgroup-modified covalent organic framework(COF-COOH)is designed to coat the polypropylene(PP)separator(COF-COOH@PP separator),realizing the regulation of ion transport and uniform lithium deposition.The plentiful and negative charge sites in the COF-COOH can suppress the diffusion of the freely movable lithium salt anion by the electrostatic interaction.Density functional theory(DFT)calculations demonstrate that the COF-COOH possesses the function of anchoring anion and desolvation.Consequently,the Li^(+)transference number(0.7),ion conductivity(0.64 mS cm^(-1)),and desolvating of Li^(+)are obviously improved by using the COF-COOH@PP separator.The modified Li-Li symmetric battery delivers stable cycle for more than 1000 h and lower voltage hysteresis(0.02 V).This dendrite-free deposition strategy holds great promise for practical application of Li metal anodes. 展开更多
关键词 covalent organic frameworks dendrite-free functionalized separator lithiophilicity groups
下载PDF
Structural properties of residual carbon in coal gasification fine slag and their influence on flotation separation and resource utilization:A review 被引量:2
16
作者 Rui Han Anning Zhou +4 位作者 Ningning Zhang Kaiqiang Guo Mengyan Cheng Heng Chen Cuicui Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第2期217-230,共14页
Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery a... Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery and the high-value utilization of residual carbon(RC)in FS are the keys to realizing the win-win situation of the coal chemical industry in terms of economic and environmental benefits.The structural properties,such as pore,surface functional group,and microcrystalline structures,of RC in FS(FS-RC)not only affect the flotation recovery efficiency of FS-RC but also form the basis for the high-value utilization of FS-RC.In this paper,the characteristics of FS-RC in terms of pore structure,surface functional groups,and microcrystalline structure are sorted out in accordance with gasification type and FS particle size.The reasons for the formation of the special structural properties of FS-RC are analyzed,and their influence on the flotation separation and high-value utilization of FS-RC is summarized.Separation methods based on the pore structural characterist-ics of FS-RC,such as ultrasonic pretreatment-pore-blocking flotation and pore breaking-flocculation flotation,are proposed to be the key development technologies for improving FS-RC recovery in the future.The design of low-cost,low-dose collectors containing polar bonds based on the surface and microcrystalline structures of FS-RC is proposed to be an important breakthrough point for strengthening the flotation efficiency of FS-RC in the future.The high-value utilization of FS should be based on the physicochemical structural proper-ties of FS-RC and should focus on the environmental impact of hazardous elements and the recyclability of chemical waste liquid to es-tablish an environmentally friendly utilization method.This review is of great theoretical importance for the comprehensive understand-ing of the unique structural properties of FS-RC,the breakthrough of the technological bottleneck in the efficient flotation separation of FS,and the expansion of the field of the high value-added utilization of FS-RC. 展开更多
关键词 coal gasification fine slag residual carbon pore structure surface functional groups microcrystalline structure flotation sep-aration resource utilization
下载PDF
Effect of group size and regrouping on physiological stress and behavior of dairy calves
17
作者 LYU Jing WANG Chao +5 位作者 ZHAO Xun-wu MIAO Er-yu WANG Zhi-peng XU Yuan BAI Xiu-juan BAO Jun 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第3期844-852,共9页
Mixing or regrouping of calves from different pens is a common animal management practice on the farm, which frequently occurs after weaning and has a negative effect on calve welfare. Social integration before regrou... Mixing or regrouping of calves from different pens is a common animal management practice on the farm, which frequently occurs after weaning and has a negative effect on calve welfare. Social integration before regrouping may relieve stresses, but more evidences are needed to verify this hypothesis. The present study aimed to investigate acute physiological and behavioral variations of individually-or group-housed calves after being introduced into a mixed group. A total of 132 postnatal calves were randomly divided into groups of 1, 3, 6 and 12 animals(S, G3, G6, and G12;6 replicates in each group) until 59 days of age. At 60 days of age, every two replicates from different groups(S, G3, G6 and G12)were introduced in a larger pen which containing 44 of the aboved experimental calves. Before and after regrouping,physiological parameters of stress, including heart rate(HR), saliva cortisol(S-CORT), saliva secretory immunoglobulin A(SIgA), interleukin-2(IL-2), interleukin-6(IL-6), tumor necrosis factor-α(TNF-α) levels, and behavioral responses were recorded. After regrouping, HR and S-CORT increased immediately(P<0.05), and higher(P<0.05) levels of such molecules were found in S calves compared to those in group-housed calves. Levels of SIgA and IL-2 were decreased(P<0.05), and the lowest(P<0.05) IL-2 values were found in S calves compared to those in group-housed calves. In addition, the introduced calves displayed a distinct behavior, including altered active and rest time, which was associated with negative emotions triggered by the novel surroundings. Allogrooming, play, exploration behaviors and lying time were increased significantly(P<0.05) in group-housed calves than those in S calves. Conversely, self-grooming, aggressive behaviors, standing and walking time were increased(P<0.05) in S calves than those in group-housed calves. These findings suggest that individually-housed calves may be more susceptible to stressors arising from regrouping than grouphoused calves, which consequently negatively affected behavioral and neuroendocrine responses. Furthermore, moving calves with previous social experience may help mitigate regrouping stress. 展开更多
关键词 CALF regrouping group size BEHAVIOR STRESS WELFARE
下载PDF
Functional groups and seasonal diversity of crustacean zooplankton in adjacent waters of Haizhou Bay,South Yellow Sea
18
作者 Zeqi ZHENG Shunan FU +5 位作者 Yixuan LI Ruping GE Hongju CHEN Zhenjiang YE Yunyun ZHUANG Guangxing LIU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第3期1007-1023,共17页
Zooplankton are important linkages in the food web and can respond nonlinearly to environmental changes.Marine organisms thrive from spring to summer.Thus,it is crucial to understand how ecological functions of zoopla... Zooplankton are important linkages in the food web and can respond nonlinearly to environmental changes.Marine organisms thrive from spring to summer.Thus,it is crucial to understand how ecological functions of zooplankton communities may shift under seasonal environmental changes during this period.Samples were collected from May to August(May,June-Ⅰ,June-Ⅱ,July-Ⅰ,July-Ⅱ,and August)in 2018 in Haizhou Bay,Jiangsu,East China for zooplankton and environmental variables.Crustaceans accounted for 75 out of 134 zooplankton taxa and 91.8%of total zooplankton abundance.The average abundance of crustacean varied between 2824.6±635.4 inds./m3 in July-Ⅱand 6502.7±1008.8 inds./m3 in June-Ⅱ.Multivariate analyses results showed that the dissimilarity of community increased gradually in the time series.Body length,feeding type,trophic group,and reproduction mode were used to investigate crustacean community functions.Trait-based functional groups contained species with similar ecological roles.Functional diversity fused the differences of species and trait.The proportion of large-sized species(2-5 mm)decreased with the increasing proportion of medium-sized species(1-2 mm).The proportion of current feeders increased with the drop in the proportion of mixed feeders.Parthenogenesis species increased with decreasing free spawners,and omnivores-carnivores increased with decreasing omnivoresherbivores.Generalized additive models suggested that temperature was the main driver of variations in crustacean zooplankton function.Seven identified functional groups varied with increasing temperature.Omnivorous-herbivorous copepods declined(90.0%-68.0%),whereas the parthenogenetic cladocerans increased(0-24.1%).The small egg-brooding ambush copepods fluctuated(6.5%-9.3%)with increasing water temperature.The other functional groups changed slightly.Functional diversity also varied according to temperature changes.The community structure and ecological function of crustacean zooplankton community showed gradual changes with increasing temperature from spring to summer. 展开更多
关键词 ZOOPLANKTON TRAIT functional group DIVERSITY Yellow Sea Haizhou Bay
下载PDF
Relative active tectonic in the metamorphic rocks of the Yaounde group: insights from geomorphic indices and topographic analysis
19
作者 Jacques Bertrand ONANA Bernard NJOM +3 位作者 Franois Mvondo OWONO Mero YANNAH Thierry Abou'ou ANGO Joseph Mvondo ONDOA 《Journal of Mountain Science》 SCIE CSCD 2023年第10期2946-2974,共29页
The Yaounde Group(YG),representing the southern edge of the North Equatorial PanAfrican Belt,consists of quartzites,schists,micaschists,amphibolites,gneisses and migmatites.Tectonism has formed a landscape characteriz... The Yaounde Group(YG),representing the southern edge of the North Equatorial PanAfrican Belt,consists of quartzites,schists,micaschists,amphibolites,gneisses and migmatites.Tectonism has formed a landscape characterized by the development of linear and folded valleys and ridges,fault scarps,V-shaped valleys,incised rivers and knickpoints.These landforms constitute important markers of the regional tectonic activity,which have been computed from spatial sources such as SRTM,DEM,hydrographical networks and geomorphic indices such as AF,T,Smf,Vf,Bs,Hi,U,SI and Li.The results highlighted a mature relief consisting of asymmetric basins generated by tilting and uplift phenomena.The relative index of active tectonics(RIAT)has been estimated from an average of eight geomorphic indices evaluated on 24 subbasins,in the study area.Four classes have been defined:class 1(1.38),very high active(1.0≤RIAT<1.5);class 2(1.50-1.88),high active(1.5≤RIAT<2.0);and class 3(2.00-2.13)moderate active(2.0≤RIAT<2.5).These three classes,respectively covering 10.20%(458 km2),80.10%(3595 km2)and 9.69%(435 km2)of the study area,have shown a highly active tectonic zone,and imply the existence of a neotectonic event in the YG.This tectonic unit(YG)was also affected by the dextral NW-SE strike-slip faulting,which cross-cut the Sanaga Shear Zone(SSZ)at Ebebda and the foliation oriented NW-SE.The tilting and uplift of rocks related to Moho ascending are responsible for crustal thinning in the Cameroon basement,more important to the Adamawa Plateau from the Cretaceous age and the reactivation of existing tectonic accidents.The presence of hills,fault scarps,reverse faults,knickpoints,V and U shaped valleys and rounded mountains testify to the interaction between tectonic uplift,lithology,climate,weathering and erosion. 展开更多
关键词 LANDFORMS Geomorphic indices RIAT Active tectonics Yaounde group
下载PDF
Fixed-time group consensus of second-order multi-agent systems based on event-triggered control
20
作者 武肖帅 孙凤兰 +1 位作者 朱伟 Jürgen Kurths 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第7期329-336,共8页
The problem of fixed-time group consensus for second-order multi-agent systems with disturbances is investigated.For cooperative-competitive network,two different control protocols,fixed-time group consensus and fixed... The problem of fixed-time group consensus for second-order multi-agent systems with disturbances is investigated.For cooperative-competitive network,two different control protocols,fixed-time group consensus and fixed-time eventtriggered group consensus,are designed.It is demonstrated that there is no Zeno behavior under the designed eventtriggered control.Meanwhile,it is proved that for an arbitrary initial state of the system,group consensus within the settling time could be obtained under the proposed control protocols by using matrix analysis and graph theory.Finally,a series of numerical examples are propounded to illustrate the performance of the proposed control protocol. 展开更多
关键词 event-triggered control group consensus multi-agent system fixed-time
下载PDF
上一页 1 2 249 下一页 到第
使用帮助 返回顶部