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Non-uniform operative temperature distribution characteristics and heat-source-controlled core-area range of local heating radiators

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Building Simulation 2023年第1期16卷 87-103页

作者： Dengjia Wang Weijia Li Yanfeng Liu Yaowen Chen Liang hu hu du State Key Laboratory of Green Building in Western China Xi'an University of Architecture and TechnologyXi'an 710055China School of Building Services Science and Engineering Xi'an University of Architecture and TechnologyXi'an 710055China Welsh School of Architecture Cardiff UniversityCardiffCF103NBUK

Heating the whole space,which is currently used in northern China,leads to high energy consumption and substantial pollution.A transition to local heating has the potential to help address this *** this paper,the effects of radiator-related parameters(position,power,and size)and room-related parameters(aspect ratio and height)on local heating were *** evaluation indices,the effective coefficient of operative temperature(OTEC)and the effective coefficient of local heating(LHEC),were *** addition,the heat source-control core-area(HSCCA)was proposed,and the effect range of heat sources in the space was evaluated by the attenuation of operative *** findings demonstrated that the radiator position has a greater influence on local heating than *** the position of the radiator was changed from"close to the inner wall"to"close to the outer wall",the LHEC(the interior one-quarter of room is a local heating zone)was found to decrease by 73%.The size of the radiator,which is close to the inner wall,doubled or quadrupled,and the LHEC increased by 9%and 18%.Moreover,rooms with a larger aspect ratio or small room height were found to be the most optimal for local heating *** area of the HSCCA decreased as the position of the radiator approached the outer *** findings of this study can be used as a design reference for the radiator when the heating mode changes from"full-space heating"to"local heating".

关键词： local heating radiator non-uniform thermal environment operative temperature mean radiant temperature temperature distribution

Current neutralization and plasma polarization for intense ion beams propagating through magnetized background plasmas in a two-dimensional slab approximation

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Frontiers of physics 2014年第2期9卷 226-233页

作者： Zhang-hu hu Mao-du Chen You-Nian Wang School of Physics and Optoeleetronic Technology Dalian University of Technology Dalian 116024 China

A two-dimensional electromagnetic Particle-in-Cell （PIC） simulation model is proposed to study the propagation of intense, ion beams with beaIn width wb small compared to the electron skin depth c/wpe through background plaslnas in tile presence of external applied magnetic fields. The effcctive eleetron gyrora,dius wge is found to be an important parameter for ion beam transport in the presence of magnetic fields,In the bealn regions, the background plasmas respond differently to the ion beanl of width wb〈wge and wb 〉 wge for the given magnetic field and beaan encrgy, For the case of beam width wb 〈 wge with relative weak external magnetic fiehts, the rotalion effects of plasma electrons a,re found to be signifieant and contributes to the signitica,nt enilaneeinent of the self electric and seif-magnetic fields. While for the ease of beam width wb 〉 wge with relative strong external magnetic fields, the rotation effects of plasma cleetrons are strongly inhibited and a, well neutraliza, tion of ion beam current can be found. Finally, the influences of diftiuent beam widths. beam energies and magnetic fields on the neutralization of ion bc, anl eurrellt are summarized for the eases of wb 〈 wge〈 c/wpe,wge 〈wb〈c/wbp and wb〈c/wpe〈wge.

关键词： current neutralization ion beams magnetized plasmas Particle-in-Cell simulations

A Numerical Modeling of the Vortex-induced Vibration of Cascade in Turbomachinery using Immersed Boundary Method

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Journal of Thermal Science 2011年第3期20卷 229-237页

作者： Guotun hu Lin du Guohua Zhong Xiaofeng Sun School of Jet Propulsion Beihang University Beijing 100191 China

Based on the immersed boundary method,a fast simulation for solving unsteady,incompressible,viscous flow associated with the oscillating cascade is established on a quasi-three-dimensional coordinate *** numerical method is applied to the simulation of the flow passing an oscillating circular cylinder which is forced to move in X direction under prescribed motions in water at rest at low Keulegan-Carpenter *** vor-tex-induced vibration of a cylinder with two degrees of freedom which oscillates in in-line direction and transverse direction is simulated using this *** results are in good agreement with the previous *** the method is extended to the oscillating cascade simulation of making various *** is found that the IBPA(inter blade phase angle) will change as the time goes on,because of the non-uniformity of the flow in the circumferential direction,until the oscillating cascade goes to a stable *** reduced velocity and the number of blades are chosen to investigate the effects of them on *** results indicate that both the reduced velocity and the number of blades are the main factors which influence *** is worth noting that the coupling process is not necessary to generate any body-fitting grids,which makes it much faster in computational process for such a complicated fluid-structure interaction problem.

关键词： turbomachinery IB method vortex-induced vibration oscillating cascade

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高加速寿命试验技术及工程应用

环境技术 2025年第1期43卷 43-49,68页

作者：唐勇胡成都陈龙中认英泰检测技术有限公司苏州215104

高加速寿命试验(HALT)是一项新型可靠性强化试验技术,一般指产品在设计研发阶段,采用比产品技术规范更为严酷的应力,加速激发产品的缺陷并对之改善,从而达到提高产品可靠性指标的目的。本文重点阐述其理论模型、试验目的、试验设备以及... 详细信息

高加速寿命试验(HALT)是一项新型可靠性强化试验技术,一般指产品在设计研发阶段,采用比产品技术规范更为严酷的应力,加速激发产品的缺陷并对之改善,从而达到提高产品可靠性指标的目的。本文重点阐述其理论模型、试验目的、试验设备以及试验方法,并结合一些产品工程上的实际应用数据统计,给相关试验需求者一些参考。

关键词：高加速寿命试验 HALT 强化试验应用

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船用西门子S120变频器及故障分析

船电技术 2025年第2期45卷 71-73,80页

作者：韩复增杜虎叶冉冉郑迁 92990部队北京100000 91999部队青岛266000

针对西门子S120变频器在某船电力推进系统中的实际应用,本文通过介绍西门子S120变频器的分类、结构组成及功能、装备运行中实际发生的常见故障及解决措施,总结了变频器常见故障排除方法,对船舶轮机人员学习和管理变频器具有一定指导作用。

关键词：西门子 S120 变频器电力推进故障

Environmental and spatial contributions to tree community assembly across life stages and scales in evergreen-deciduous broadleaf karst forests,southwest China

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Journal of Forestry Research 2023年第5期34卷 1323-1331页

作者： Liang Su hu du Fuping Zeng Wanxia Peng hua Wang Kelin Wang Menzhen Lu Tongqing Song Key Laboratory of Agro-Ecological Processes in Subtropical Region Institute of Subtropical AgricultureChinese Academic of SciencesChangshaPeople’s Republic of China Guangxi Key Laboratory of Karst Ecological Processes and Services Huanjiang Observation and Research Station of Karst EcosystemChinese Academic of SciencesHuanjiangPeople’s Republic of China College of Resources and Environment Hunan Agricultural UniversityChangshaPeople’s Republic of China

Spatial and environmental processes are two ecological processes that have attracted considerable attention in plant community assembly,depending on sampling scale and life ***,the processes that determine community assembly have not been studied in the karst region of southwest *** this study,a 25-ha(500 m×500 m)monitoring plot within the subtropical climax forest in the karst region was established and canonical correspondence analysis was used to reveal the effects of topography and soil on the spatial patterns of tree community *** study suggests that spatial processes dominate species composition and the combined effects of spatial and environmental processes play an important *** interpretation rate increases with enlarging the sampling ***,the pattern of variation partitioning was similar in different life *** variables significantly affected species composition at different sampling sizes and life histories and had a higher interpretation rate of species composition on larger s ampling *** wetness index was the most important variable to explain species composition of the environmental *** results suggest that it is necessary to consider the relative importance of environmental and spatial factors on community assembly to better understand,conserve,and manage subtropical karst forests.

关键词： Species composition Spatial distribution Variation partitioning Community assembly Karst ecosystems

Spherical Magnetic Fe-Alginate Microgels Fabricated by Droplet-Microfluidics Combining with an External Crosslinking Approach and the Study of Their pH Dependent Fe³⁺ Release Behaviors

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CHINESE JOURNAL OF POLYMER SCIENCE 2024年第2期43卷 289-302页

作者： Chen, Jie Yu, Run-Yu Wang, Kai-Qi Zhang, Zhe-Yu Ardekani, Arezoo hu, Yuan-du Beijing Jiaotong Univ Sch Phys Sci & Engn Dept Mat Sci & Engn Beijing 100044 Peoples R China South China Univ Technol Guangdong Prov Key Lab Tech & Equipment Macromol A Guangzhou 510641 Peoples R China Fudan Univ State Key Lab Mol Engn Polymers Shanghai 200438 Peoples R China Purdue Univ Sch Mech Engn Dept Math 585 Purdue Mall W Lafayette IN 47907 USA

due to the rapid development and potential applications of iron(III)-alginate (Fe-Alg) microgels in biomedical as well as environmental engineering, this study explores the preparation and characterization of spherical Fe-Alg microgels using droplet microfluidics combined with an external ionic crosslinking method. This study focused on the role of Fe3+ and examined its effects on the physical/chemical properties of microgels under different ionic conditions and reduced or oxidized states. The pH-dependent release behavior of Fe3+ from these microgels demonstrates their potential biomedical and environmental applications. Furthermore, the microgels can exhibit magnetism simply by utilizing in situ oxidation, which can be further used for targeted drug delivery and magnetic separation technologies.

关键词： Fe-alginate microgels Droplet microfluidics In situ oxidation Magnetism

Spatial Heterogeneity of Soil Mineral Oxide Components in Depression Between Karst Hills,Southwest China

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Chinese Geographical Science 2014年第2期24卷 163-179页

作者： du hu WANG Kelin PENG Wanxia ZENG Fuping SONG Tongqing ZHANG Hao LU Shiyang Key Laboratory of Agro-ecological Processes in Subtropical Region Institute of Subtropical AgricultureChinese Academy of Sciences huanjiang Observation and Research Station for Karst Ecosystem Chinese Academy of Sciences University of Chinese Academy of Sciences

In karst regions,the spatial heterogeneity of soil mineral oxides and environmental variables is still not *** investigated the spatial heterogeneity of SiO2,Al2O3,Fe2O3,CaO,MgO,P2O5,K2O,and MnO contents in the soils of slope land,plantation forest,secondary forest,and primary forest,as well as their relationships with environmental variables in a karst region of Southwest ***,principal component analysis(PCA),and canonical correlation analysis(CCA)were applied to analyze the field *** results show that SiO2was the predominant mineral in the soils(45.02%–67.33%),followed by Al2O3and *** soil mineral oxide components had a strong spatial dependence,except for CaO,MgO,and P2O5in the plantation forest,MgO and P2O5in the secondary forest,and CaO in the slope *** reduction in PCA was not appropriate due to the strong spatial heterogeneity in the *** mineral oxide components,the main factors in all ecosystems,had greater influences on vegetation than those of conventional soil *** were close relationships between soil mineral oxide components and vegetation,topography,and conventional soil *** oxide components affected species diversity,organic matter and nitrogen levels.

关键词： karst soil mineral oxide component ecosystem principal component analysis(PCA) canonical correlation analysis(CCA)

Increasing plant species diversity aggravates microbial phosphorus limitation but alleviates microbial carbon limitation in a subtropical forest

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JOURNAL OF PLANT ECOLOGY 2024年第6期17卷 376-389页

作者： Gao, Kun du, hu Zhu, Zihong Fang, Yuantian Li, Dejun Chinese Acad Sci Inst Subtrop Agr Hunan Prov Key Lab Agroecol Engn Changsha 410125 Peoples R China Chinese Acad Sci Inst Subtrop Agr Guangxi Key Lab Karst Ecol Proc & Serv Huanjiang Observat & Res Stn Karst Ecosyst Huanjiang 547100 Peoples R China Guangxi Ind Technol Res Inst Karst Rocky Desertifi Nanning 530012 Peoples R China Univ Chinese Acad Sci Coll Resources & Environm Beijing 101408 Peoples R China

The relative limitation of microbes by soil organic carbon (SOC), nitrogen (N) and phosphorus (P) is linked with soil microbial activities, so how change of plant species diversity (PSD) affects microbial resource limitation would partly determine its impacts on SOC dynamics and nutrient cycling. However, the responses of microbial resource limitation to increasing PSD have poorly explored. Here, 45 plots covering a natural PSD gradient were used to investigate the effects of PSD on microbial resource limitation in a subtropical forest. Extracellular enzymatic stoichiometry along with a laboratory N and P addition experiment were used to determine microbial resource limitation. Contents of microbial biomass C, N and P significantly increased, but C:P and N:P ratios in microbial biomass were unchanged as PSD increased. Soil microbes were generally co-limited by C and P, but not by N across the 45 plots. Increasing PSD did not alter microbial N limitation, alleviated microbial C limitation and aggravated microbial P limitation. The alleviated microbial C limitation or aggravated microbial P limitation was attributed to increased soil C availability but decreased P availability, which resulted in stimulated soil C:P and N:P ratios and in turn greater C:P and N:P imbalance between soil and microbial biomass under higher PSD. Our results highlight the divergent effects of increasing PSD on microbial resource limitation. Considering that microbial C and P limitations are widespread, the patterns observed in the current study should be applicable broadly. (sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(SOC),(sic)(N)(sic)(sic)(P)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(PSD)(sic)(sic)(sic)(sic)(sic)(si

关键词： microbial carbon limitation microbial phosphorus limitation plant species diversity extracellular enzymatic stoichiometry soil nutrient availability (sic)(sic)(sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) (sic)(sic)(sic)(sic)(sic)(sic)(sic)