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Spatial Morphology Evolution Characteristics Analysis of the Resident Population Distribution in Henan, China
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作者 Kaiguang Zhang Hongling Meng +1 位作者 Mingting Ba Danhuan Wen 《Journal of Geoscience and Environment Protection》 2024年第3期163-180,共18页
The population spatial distribution pattern and its evolving pattern play an important role in regional allocation of social resources and production factors, formulation of regional development plans, construction of... The population spatial distribution pattern and its evolving pattern play an important role in regional allocation of social resources and production factors, formulation of regional development plans, construction of a better life society, and promotion of regional economic development. Based on the resident population statistics data of Henan province from 2006 to 2021, with county as the basic study unit, the paper studies the spatial morphology characteristics and its evolution patterns of resident population distribution, by using spatial analysis methods such as population distribution center, standard deviation ellipse, and spatial auto correlation analysis. The results show that: the resident population spatial distribution shows unbalanced state, the population agglomeration areas mainly distribute in the northeast part and north part, where the resident population growth rate is significantly higher than other regions, over time, this trend is gradually becoming significant. The resident population distribution has a trend of centripetal concentration, with the degree and trend of centripetal gradually strengthening. The resident population distribution has obvious directional characteristics, but the significance is not high, the weighted resident population average center is approximately located at (4.13740˚N, 113.8935˚E), and the azimuth of the distribution axis is approximately 11.19˚. The population distribution has obvious agglomeration characteristics, with the built-up areas of Zhengzhou and Luoyang as their centers, where have a significant siphon effect on the surrounding population. The southern and southwestern regions in the province form a relatively stable belt area of Low-Low agglomeration areas. 展开更多
关键词 Resident Population Spatial distribution Spatial Morphology Temporal and Spatial Evolution center Migration Standard Deviation Ellipse Spatial Autocorrelation
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An Improved Genetic Algorithm for Allocation Optimization of Distribution Centers 被引量:7
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作者 钱晶 庞小红 吴智铭 《Journal of Shanghai Jiaotong university(Science)》 EI 2004年第4期73-76,共4页
This paper introduced an integrated allocation model for distribution centers (DCs). The facility cost, inventory cost, transportation cost and service quality were considered in the model. An improved genetic algorit... This paper introduced an integrated allocation model for distribution centers (DCs). The facility cost, inventory cost, transportation cost and service quality were considered in the model. An improved genetic algorithm (IGA) was proposed to solve the problem. The improvement of IGA is based on the idea of adjusting crossover probability and mutation probability. The IGA is supplied by heuristic rules too. The simulation results show that the IGA is better than the standard GA(SGA) in search efficiency and equality. 展开更多
关键词 distribution center allocation optimization improved genetic algorithm
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Research on Site Selection Model of Distribution Center of Agricultural Products 被引量:3
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作者 LI Yong-xin,YIN Chun-wu,HUI Xiao-jian Department of Basic Courses,Xijing University,Xi’an 710123,China 《Asian Agricultural Research》 2011年第4期132-134,共3页
In the light of the practical situation of logistics distribution of agricultural products,we primarily select transportation factor,economic factor,environment factor,and other factors,to establish evaluation index s... In the light of the practical situation of logistics distribution of agricultural products,we primarily select transportation factor,economic factor,environment factor,and other factors,to establish evaluation index system of site selection of distribution center of agricultural products.And then we adopt the analytic hierarchy process method to calculate weight of site selection of distribution center of agricultural products.Under the circumstance that the evaluation information is interval number,we use uncertain and multiple attribute decision making method to establish site selection model of distribution center of agricultural products.Finally,taking one city as an example,we discuss the application of this model in site selection of distribution center of agricultural products.The results of empirical analysis show that the model we established fully considers the randomness and uncertainty in the process of evaluation,so as to make the results of evaluation more objective,in line with reality.So the effect of evaluation is better as against the former real number evaluation calibration. 展开更多
关键词 distribution center of AGRICULTURAL PRODUCTS Model
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EFFECTS OF EXTERNAL DONOR ON ACTIVE CENTER DISTRIBUTION OF SUPPORTED ZIEGLER-NATTA CATALYST 被引量:1
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作者 范志强 M.CarmelaSacchi PaoloLocatelli 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1997年第3期217-225,共9页
The composition distribution (CD) and microisotacticity distribution (ID) of propene/1-hexene copolymer synthesized by MgCl2/DIBP/TiCl4 (DIBP: diisobutyl phthalate) were determined by fractionating the copolymers acco... The composition distribution (CD) and microisotacticity distribution (ID) of propene/1-hexene copolymer synthesized by MgCl2/DIBP/TiCl4 (DIBP: diisobutyl phthalate) were determined by fractionating the copolymers according to crystallinity and characterizing the fractions by (CNMR)-C-13. The effects of two alkoxysilane donors, triethoxyphenylsilane (PTES) and dimethoxydi-tert-butylsilane (TBMS), on CD and ID of the copolymers were compared. Three main parts in the CD diagram of each copolymer were distinguished, which were correlated to active center distribution (ACD) based on three groups of different active centers. By studying the changes in l-hexene content, microisotacticity and reactivity ratio product of three typical fractions, the effects of external donor on ACD were better elucidated. It was found that TBMS shows much stronger effects on ACD than PTES. In the former system, most fractions were produced on active centers with relatively lower r(1)r(2), higher reactivity to I-hexene, and higher stereospecificity as compared to the system without external donor. It is concluded that the observed very extensive changes in ACD are mainly resulted by the formation of new types of active centers, possibly by coordination of external donor to certain positions on the catalyst. 展开更多
关键词 supported Ziegler-Natta catalyst propene/1-hexene copolymer external donor active center distribution
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Study on the distribution of active centers in novel low Ti-loading MgCl2-supported Ziegler-Natta catalyst 被引量:1
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作者 王剑峰 王立 +2 位作者 赵振荣 王文钦 陈涛 《Journal of Zhejiang University Science》 EI CSCD 2004年第8期912-917,共6页
Novel MgCl2-supported Ziegler-Natta (Z-N) catalysts prepared using a new one-pot ball milling method can effectively control the amounts of Ti-loading in the catalysts. Complex GPC data on polypropylene synthesized by... Novel MgCl2-supported Ziegler-Natta (Z-N) catalysts prepared using a new one-pot ball milling method can effectively control the amounts of Ti-loading in the catalysts. Complex GPC data on polypropylene synthesized by these novel catalysts were analyzed using the method of fitting the molecular weight distribution (MWD) curves with a multiple Flory-Schulz function. It was found that multiple active centers exist in these novel catalysts. Detailed study of the effects of the Ti-loadings in the catalysts on the distribution of the active centers showed that the Ti-loadings in the novel MgCl2-supported Z-N catalysts might affect the proportion of each type of active centers; and might be the main factor responsible for the effect of the Ti-loadings on the microstructure, the molecular weight and molecular weight distribution width of the resultant polymer, the catalytic activity and polymerization kinetics. 展开更多
关键词 Supported Ziegler-Natta catalyst Propylene polymerization Active center Molecular weight distribution
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Application of Robust Strategies in Location Selection of Logistics Distribution Center for Fresh Agricultural Products 被引量:2
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作者 Liu YANG Bing ZHAO +2 位作者 Pinyuan ZHAO Bingqing ZHANG Xuejie BAI 《Asian Agricultural Research》 2020年第10期7-9,共3页
In view of the uncertainty in the location selection of logistics distribution center for the fresh agricultural products,the present study established a robust model based on the maximization of principal component s... In view of the uncertainty in the location selection of logistics distribution center for the fresh agricultural products,the present study established a robust model based on the maximization of principal component score taking budget cost parameters as an example.In the process of model solving,the interval form of the uncertain set was used to clarify the constraint conditions,to transform into a certain 0-1 integer linear programming model,so as to solve with the aid of LINGO software.Finally,through studying the location selection of logistics distribution center for fresh agricultural products in the Beijing-Tianjin-Hebei region,it analyzed the application of the robust model and tested the validity of the model. 展开更多
关键词 Fresh agricultural products Logistics distribution center location Robust model
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Study on Location of Wuhan Steel Logistics Distribution Center 被引量:2
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作者 Mengyue Yang Zhenping Li 《Open Journal of Applied Sciences》 2016年第13期938-943,共7页
This paper studies the location of Wuhan steel logistics distribution center. First of all, according to Wuhan Iron and Steel Plant sales in Hunan Province and the relative position of the city, the transport costs ar... This paper studies the location of Wuhan steel logistics distribution center. First of all, according to Wuhan Iron and Steel Plant sales in Hunan Province and the relative position of the city, the transport costs are calculated from Wuhan Iron and Steel Plant to the demand point. We further analyze the necessity of establishing steel logistics distribution center, using the precise center of gravity to determine the actual location of the distribution center. After the establishment of distribution center, the total freight is reduced by 15.46 million yuan from Wuhan Iron and Steel Plant to each city in Hunan province via distribution center each year. The results of this paper can provide theoretical basis for the logistics node planning of related enterprises. 展开更多
关键词 Steel Logistics distribution center LOCATION Precise center of Gravity Method
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Research and Application for the Regularity of Distribution about Curvature Radius and Curvature Center of the Linkage Point Track in a Link Mechanism 被引量:2
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作者 WANG Yun-di WANG Liang-wen +1 位作者 ZHANG Hang-wei DONG Hai-jun 《International Journal of Plant Engineering and Management》 2012年第3期160-168,共9页
It is illustrated that there exists an inflection circle on the linkage rigid body by the principle of relative motion. Confirmed methods of the inflection circle, curvature radius and curvature center of the point tr... It is illustrated that there exists an inflection circle on the linkage rigid body by the principle of relative motion. Confirmed methods of the inflection circle, curvature radius and curvature center of the point track on the linkage rigid body are given in the case of the different contact type of move instantaneous center line and static instantaneous center line. The regularity of distribution of curvature radius and curvature center of the point track is researched. The identification methods called determination parameters and auxiliary vertical line of the diameter and direction of the inflection circle in the four bar mechanism are pointed out. A design method of the crane hoisting mechanism is discussed in the end of this paper. 展开更多
关键词 link mechanism linkage point track instantaneous center line inflection circle determination parameters and auxiliary vertical line curvature radius curvature center distribution regularity the crane hoisting mechanism
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DEPENDENCE OF THE DISTRIBUTION OF ACTIVE CENTERS ON MONOMER IN SUPPORTED ZIEGLER-NATTA CATALYSTS
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作者 范志强 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2008年第5期605-610,共6页
Distribution of active centers(ACD)of ethylene or 1-hexene homopolymerization and ethylene-1-hexene copolymerization with a MgCl_2/TiCl_4 type Z-N catalyst were studied by deconvolution of the polymer molecular weight... Distribution of active centers(ACD)of ethylene or 1-hexene homopolymerization and ethylene-1-hexene copolymerization with a MgCl_2/TiCl_4 type Z-N catalyst were studied by deconvolution of the polymer molecular weight distribution into multiple Flory components.Each Flory component is thought to be formed by a certain type of active center. ACD of ethylene-1-hexene copolymer with very low 1-hexene incorporation was compared with that of ethylene homopolymer to see the effect of introducingα-olefin on ethyle... 展开更多
关键词 Supported Ziegler-Natta catalyst Active center distribution Monomer.
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Pressure distribution of combining center cavity slipper for axial piston pump
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作者 王亚军 苑士华 《Journal of Beijing Institute of Technology》 EI CAS 2014年第4期452-456,共5页
In order to improve lubricating characteristics of slippers in an axial piston pump, the combining center cavity slipper approach was proposed based on slipper shape and moving characteristic. The cylindrical coordina... In order to improve lubricating characteristics of slippers in an axial piston pump, the combining center cavity slipper approach was proposed based on slipper shape and moving characteristic. The cylindrical coordinate was used in the lubricant area and mesh was made. The blockweight approach was implemented to deal with non-coincidence of mesh and shallow recess border in numerical method. The finite control volume method was applied in calculating pressure distribution. The flow conservation equation and film thickness model were resolved through Gauss-Siedel relaxation iteration. The calculation and analysis results indicate that compared to the slipper (1) slip- per pressure distribution is improved; (2) hydrodynamic pressure of the combining slipper is greatly increased; (3) inclining degree is greatly reduced; (4) negative pressure in lubricant film disappear. So the combining center cavity slipper is lubricated better. 展开更多
关键词 axial piston pump combining center cavity slipper finite control volume method pressure distribution
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An Uncertain Programming Model for Competitive Logistics Distribution Center Location Problem
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作者 Bingyu Lan Jin Peng Lin Chen 《American Journal of Operations Research》 2015年第6期536-547,共12页
We employ uncertain programming to investigate the competitive logistics distribution center location problem in uncertain environment, in which the demands of customers and the setup costs of new distribution centers... We employ uncertain programming to investigate the competitive logistics distribution center location problem in uncertain environment, in which the demands of customers and the setup costs of new distribution centers are uncertain variables. This research was studied with the assumption that customers patronize the nearest distribution center to satisfy their full demands. Within the framework of uncertainty theory, we construct the expected value model to maximize the expected profit of the new distribution center. In order to seek for the optimal solution, this model can be transformed into its deterministic form by taking advantage of the operational law of uncertain variables. Then we can use mathematical software to obtain the optimal location. In addition, a numerical example is presented to illustrate the effectiveness of the presented model. 展开更多
关键词 COMPETITIVE LOCATION LOGISTICS distribution center UNCERTAIN PROGRAMMING Uncertainty Theory
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On Deciding Sustainable Distribution Center of a Supply Chain
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作者 Ronsen Purba Herman Mawengkang 《Journal of Mathematics and System Science》 2013年第9期454-462,共9页
A supply chain is a network that performs the procurement of raw material, the transportation of raw material to intermediate and end products, and the distribution of end products to retailers or customers. Installat... A supply chain is a network that performs the procurement of raw material, the transportation of raw material to intermediate and end products, and the distribution of end products to retailers or customers. Installation and operation of distribution centers and all downstream members play a vital role in fulfilling the customers demand and have a great impact for supply chain management performance. In this paper we address a new approach for solving a supply chain optimization model to decide distribution centers based on environmental consideration. 展开更多
关键词 Supply chain distribution center SUSTAINABILITY MINLP MODELING
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Research On Picking Methods in Agricultural Products Distribution Center
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作者 Yongsheng Deng Kesheng Tang Wei Liu 《Journal of Zhouyi Research》 2014年第1期9-12,共4页
关键词 配送中心 农产品 农业经济发展 物流服务 采摘方法 生活水 农民收入 流通领域
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Study on the E-commerce Ordering Platform of CKD/IKD 被引量:2
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作者 YIN Xiaoqing~1 LIU Wei~2 1.College of Mechanical Engineering,Chongqing University,Chongqing 400044,China 2.College of Economics Business Administration,Chongqing University,Chongqing 400044,China 《武汉理工大学学报》 CAS CSCD 北大核心 2006年第S2期490-492,共3页
CKD/IKD is a new technology management method which should be used instead of commerce mode of CBU.In the international trade,as to the products with fast update,complex structure,mass variety,complicated sales states... CKD/IKD is a new technology management method which should be used instead of commerce mode of CBU.In the international trade,as to the products with fast update,complex structure,mass variety,complicated sales states and multi- mode configuration,when they are exported to enterprises without independent technology of products design from the OEM suppli- ers in the form of CKD/IKD.The all-around intellectualized management of CKD/IKD customization,purchase and supply will be realized by transforming automatically between CKD/IKD orders and parts orders in ERP systems through KD virtual collabo- rative center,combining the e-commerce sales system,ERP,SCM,CRM,PDM and export management system. 展开更多
关键词 CKD/IKD e-commerce VIRTUAL COLLABORATIVE center
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Numerical simulation of airflow distribution in mine tunnels 被引量:4
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作者 Ding Cui He Xueqiu Nie Baisheng 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2017年第4期663-667,共5页
Based on 3D modelling of typical tunnels in mines, the airflow distribution in a three-center arch-section tunnel is investigated and the influence of air velocity and cross section on airflow distribution in tunnels ... Based on 3D modelling of typical tunnels in mines, the airflow distribution in a three-center arch-section tunnel is investigated and the influence of air velocity and cross section on airflow distribution in tunnels is studied. The average velocity points were analyzed quantitatively. The results show that the airflow pattern is similar for the three-center arch section under different ventilation velocities and cross sectional areas. The shape of the tunnel cross section and wall are the critical factors influencing the airflow pattern. The average velocity points are mainly close to the tunnel wall. Characteristic equations are developed to describe the average velocity distribution, and provide a theoretical basis for accurately measuring the average velocity in mine tunnels. 展开更多
关键词 Mine tunnel TURBULENCE Airflow distribution Three-center arch Average velocity
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A platform for communicating construction material information between e-commerce systems
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作者 Stephen C W Kong 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2004年第5期541-547,共7页
E-commerce systems for construction material procurement are becoming increasingly important in Hong Kong. These E-commerce systems are non-interoperable and create problems for the buyers who use these systems to pur... E-commerce systems for construction material procurement are becoming increasingly important in Hong Kong. These E-commerce systems are non-interoperable and create problems for the buyers who use these systems to purchase construction materials. This paper presents the mobile agent-based approach and Web services-based approach for enabling interoperation of these systems in the E-Union environment. 展开更多
关键词 e-commerce mobile agent Web services distributed computing construction material
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Research on location of underground explosion center based on distributed testing system
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作者 WANG Tian-hao ZHANG Zhi-jie CHENG Hao 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2020年第2期112-117,共6页
Distributed testing system has strong applicability in the field of dynamic testing,which can centrally manage the testing equipment in different locations through the local area network,and meet the new requirements ... Distributed testing system has strong applicability in the field of dynamic testing,which can centrally manage the testing equipment in different locations through the local area network,and meet the new requirements of the test.Based on the theory of seismic location,the location of underground explosion center was studied.The applicability of seismic location theory to the location of underground explosion center was verified by simulating the underground explosion with LS-DYNA simulation platform.Combined with distributed testing system theory and weighting method,the optimal distribution method of test points was summarized through data analysis. 展开更多
关键词 explosion center location LS-DYNA distributed testing system seismic location weighting method
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Study on the Self-supporting Logistics Mode based on B2C E-commerce Enterprises
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作者 Ting LI 《International Journal of Technology Management》 2015年第2期87-89,共3页
Taking B2C E-commerce enterprises as the center, it can be divided into a set of logistics activities upstream supply chain logistics producer to B2C e-commerce enterprises, and the B2C e-commerce enterprise logistics... Taking B2C E-commerce enterprises as the center, it can be divided into a set of logistics activities upstream supply chain logistics producer to B2C e-commerce enterprises, and the B2C e-commerce enterprise logistics to client consumer, and the paper focuses on the study of self-supporting logistics for the E-commerce enterprise. According to the development status of current B2C electronic commerce enterprise in our country and logistics, the paper study B2C electric business enterprise how to correctly choose the logistics mode and how to promote the business logistics operation level. 展开更多
关键词 B2C e-commerce Logistics distribution Self-supporting Logistics Mode Operating mechanism
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Fast and scalable routing protocols for data center networks
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作者 Mihailo Vesovic Aleksandra Smiljanic Dusan Kostic 《Digital Communications and Networks》 SCIE CSCD 2023年第6期1340-1350,共11页
Data center networks may comprise tens or hundreds of thousands of nodes,and,naturally,suffer from frequent software and hardware failures as well as link congestions.Packets are routed along the shortest paths with s... Data center networks may comprise tens or hundreds of thousands of nodes,and,naturally,suffer from frequent software and hardware failures as well as link congestions.Packets are routed along the shortest paths with sufficient resources to facilitate efficient network utilization and minimize delays.In such dynamic networks,links frequently fail or get congested,making the recalculation of the shortest paths a computationally intensive problem.Various routing protocols were proposed to overcome this problem by focusing on network utilization rather than speed.Surprisingly,the design of fast shortest-path algorithms for data centers was largely neglected,though they are universal components of routing protocols.Moreover,parallelization techniques were mostly deployed for random network topologies,and not for regular topologies that are often found in data centers.The aim of this paper is to improve scalability and reduce the time required for the shortest-path calculation in data center networks by parallelization on general-purpose hardware.We propose a novel algorithm that parallelizes edge relaxations as a faster and more scalable solution for popular data center topologies. 展开更多
关键词 Routing protocols Data center networks Parallel algorithms distributed algorithms Algorithm design and analysis Shortest-path problem SCALABILITY
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数据中心冷却系统研究及应用进展 被引量:1
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作者 周峰 谷文龙 +1 位作者 马国远 晏祥慧 《制冷与空调》 2024年第2期63-71,共9页
为加速实现数据中心节能降耗的目标,在合理、高效、最大化地利用自然冷源的同时,更不能忽视机械制冷系统本身能效的提升。加强自然冷却与机械制冷的协同,降低数据中心PUE,充分发挥安全稳定、高效运行的数据中心冷却系统自身能效至关重... 为加速实现数据中心节能降耗的目标,在合理、高效、最大化地利用自然冷源的同时,更不能忽视机械制冷系统本身能效的提升。加强自然冷却与机械制冷的协同,降低数据中心PUE,充分发挥安全稳定、高效运行的数据中心冷却系统自身能效至关重要。本文通过对气流组织、供/回水温度和冷却系统部件及形式3个方面的研究梳理,总结分析数据中心冷却系统节能提效有关技术研究与应用进展,从而为绿色、高效数据中心冷却系统的研发提供参考和借鉴。 展开更多
关键词 数据中心 冷却系统 气流组织 供回水温度 部件及形式
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