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Heat Transfer and Friction Characteristics of Printed Circuit Heat Exchangers with Different Channel Structures for S-CO_(2) Power System

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Journal of Thermal Science 2024年第3期33卷 1132-1147页

作者： jiang tao LI Mingjia Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an710049China School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081China

Printed circuit heat exchanger(PCHE)has been widely used in supercritical carbon dioxide(S-CO_(2))power systems because of its high heat transfer efficiency and good ***,due to the large variety of PCHE configurations,channel selection in practical applications lacks a ***,this paper discussed the heat transfer and friction characteristics and the synergy of three fields in the channel under the guidance of the field synergy principle for four typical PCHE ***,the comprehensive performance of four channels was ***,the heat transfer and friction factor correlations for S-CO_(2)in four channels were *** findings demonstrate that the synergy of velocity and pressure fields of the straight channel PCHE is better(β≈180°),so its resistance loss is relatively *** zigzag and sinusoidal wavy channels and the airfoil fins can reduce the angle a between the temperature gradient and velocity,thus enhancing the heat *** sinusoidal wavy channel can reduce flow resistance compared to the zigzag channel due to the rounded *** streamlined airfoil structure can guide the flow and reduce backflow,thus reducing resistance *** the range of Re studied in this paper,the maximum error of the proposed heat transfer and friction factor correlations of PCHE is 7.0%,which shows good fitting *** research in this paper can provide a reference for the selection and design of PCHE with different channel configurations.

关键词： printed circuit heat exchanger supercritical carbon dioxide typical channel structure field synergy analysis

Stable carbon isotope composition and intrinsic water use efficiency in plants along an altitudinal gradient on the eastern slope of Yulong Snow Mountain, China

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Ecological Processes 2024年第2期13卷 218-230页

作者： Feng jiang tao Pu Zi-Jing xue Yan-Wei Ma Xiao-Yi Shi Fu-Xi Shi College of Geography and Environmental Sciences Zhejiang Normal University Yulong Snow Mountain Glacier and Environment Observation and Research Station/State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-Environment and ResourcesChinese Academy of Sciences Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed College of Forestry Jiangxi Agricultural University

Background Stable carbon isotope composition(δ13Cp) can be used to estimate the changes in intrinsic water use efficiency（iWUE） in plants,which helps us to better understand plants' response strategies to climate *** study focused on the variations in δ13Cpand iWUE for the different life-form plants（i.e.,herbs,shrubs,and trees）along an altitudinal gradient（3300,3600,3900,4100,4300,and 4500 m） on the eastern slope of Yulong Snow Mountain,southeastern margin of the Qinghai-Tibet *** response mechanisms of δ13Cpand iWUE for different life-form plants to altitude were thoroughly analyzed in this mountain *** The δ13Cpvalues of plants on the eastern slopes of Yulong Snow Mountain ranged from-30.4‰to-26.55‰,with a mean of-28.02‰,indicating a dominance of *** δ13Cpand iWUE values varied among different life-form plants in the order of herbs> shrubs> trees,particularly in 3600,3900,and 4300 ***δ13Cpand iWUE values for herbs and shrubs increased with altitude and were mainly controlled by air *** two parameters for trees exhibited a trend of initial decrease followed by an increase with *** 3900 m,the δ13Cpand iWUE values decreased with altitude,influenced by soil ***,above 3900 m,the two parameters increased with altitude,mainly regulated by air *** addition,iWUE was positively correlated with leaf P content but negatively correlated with leaf N:P ratio,especially for herbs and trees,suggesting that P plays a key role in modulating iWUE in this *** The diffe rentiated responses of water availability for different life-form plants to a higher altitudinal gradient are regulated by air temperature,soil moisture,and leaf P content in the Yulong Snow *** results provide valuable insights into understanding the wate r-carbon relationships in high-altitude ecosystems.

关键词： Stable carbon isotope Water use efficiency Altitude Life form Yulong Snow Mountain

Experimental Study on Wire Melting Control Ability of Twin-Body Plasma Arc

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 184-194页

作者： Ruiying Zhang Fan jiang Long xue School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing 102617China Beijing Academy of Safety Engineering and Technology Beijing 102617China College of Mechanical and Energy Engineering Beijing University of TechnologyBeijing 100124China

The twin-body plasma arc has the decoupling control ability of heat transfer and mass transfer,which is beneficial to shape and property control in wire arc additive *** this paper,with the wire feeding speed as a characteristic quantity,the wire melting control ability of twin-body plasma arc was studied by adjusting the current separation ratio(under the condition of a constant total current),the wire current/main current and the position of the wire in the arc axial *** results showed that under the premise that the total current remains unchanged(100 A),as the current separation ratio increased,the middle and minimum melting amounts increased approximately synchronously under the effect of anode effect power,the first melting mass range remained constant;the maximum melting amount increased twice as fast as the middle melting amount under the effect of the wire feeding speed,and the second melting mass range was *** the wire current increased,the anode effect power and the plasma arc power were both factors causing the increase in the wire melting amount;however,when the main current increased,the plasma arc power was the only factor causing the increase in the wire melting *** average wire melting increment caused by the anode effect power was approximately 2.7 times that caused by the plasma arc *** minimum melting amount was not affected by the wire-torch distance under any current separation ratio *** the current separation ratio increased and reached a threshold,the middle melting amount remained constant with increasing wire-torch *** the current separation ratio continued to increase and reached the next threshold,the maximum melting amount remained constant with the increasing wire-torch *** effect of the wire-torch distance on the wire melting amount reduced with the increase in the current separation *** this study,the decoupling mechanism and ability of this innovative

关键词： Twin-body plasma arc Melting control ability Melting amount Current separation ratio

Effect of the grain boundary character distribution on the sulfur corrosion behaviour and mechanisms of copper windings under different high temperatures

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High Voltage 2024年第3期9卷 566-580页

作者： Xu Dai Yuan Yuan jiang Zhou Guoyong Liu tao Zhu Huiying Xiang Qi Yu xue Gao Ruijin Liao State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina College of Materials Science and Engineering Chongqing UniversityChongqingChina Dongfang Electric Machinery Co. LtdDeyangChina

As a typical failure phenomenon in transformers,sulfur corrosion has garnered significant attention in the field of high-voltage *** boundary character distribution(GBCD)copper windings have been introduced to enhance sulfur corrosion resistance by slowing down intergranular *** this study,the sulfur corrosion behaviour and mechanisms of the GBCD copper windings under various temperatures were experi-mentally and theoretically *** show that GBCD can enhance the corrosion resistance of copper in liquid *** the increase in temperatures,the insulating properties of oil and papers in traditional copper windings experience notable degradation,while GBCD copper windings show more stable insulating *** addition,modelling of grain boundary energy indicates that the grain boundary structure of GBCD copper windings has a lower average interface energy of 0.170 eV/Å***-culations of reaction thermodynamics show that GBCD copper windings possess a higher failure temperature(135.2℃)and inhibition degree(activation energy)of the sulfur corrosion(32,557.62 J/mol),revealing the stability and enhanced sulfur corrosion resis-tance at elevated temperatures.

关键词： corrosion grain copper

The Mass Assembly History for Galaxies with MaNGA

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Research in Astronomy and Astrophysics 2024年第3期24卷 58-69页

作者： xue Ge Hong-tao Wang Cheng-Long Lei Yun-Jun Guo Yi-Long jiang Xiao-Xiao Cao School of Physics and Information Engineering Jiangsu Second Normal University jiangsu Province Engineering Research Center of Basic Education Big Data Application Jiangsu Second Normal University Key Laboratory of Modern Astronomy and Astrophysics Nanjing UniversityMinistry of Education School of Science Langfang Normal University

How galaxies assemble masses through their own star formation or interaction with the external environment is still an important topic in the field of galaxy formation and *** use Value Added Catalogs with galaxy features that are spatially and temporally resolved from Sloan Digital Sky Survey Data Release 17 to investigate the mass growth histories of early-type galaxies(ETGs)and late-type galaxies(LTGs).We find that the mass growth of ETGs is earlier than that of LTGs for massive galaxies(M_(*)>10^(10)M_⊙),while low-mass(M_(*)≤10^(10)M_⊙)ETGs have statistically similar mass assembly histories as low-mass *** stellar metallicity of all massive galaxies shows a negative gradient and basically does not change with ***,in low-mass galaxies,the stellar metallicity gradient of elliptical galaxies is negative,and the stellar metallicity gradient of lenticular and spiral galaxies evolves from positive to *** are not all in a high-density environment,but exhibit mass *** the tidal strength increases,the star formation rate of low-mass ETGs rapidly *** results support a picture where massive galaxies exhibit inside-out quenching mode,while low-mass galaxies show outside-in quenching *** effects play an important role in regulating the mass assembly histories of low-mass ETGs.

关键词： Galaxy evolution-galaxies star formation-Galaxy formation

Spatio-temporal variability of surface chlorophyll a in the Yellow Sea and the East China Sea based on reconstructions of satellite data of 2001-2020

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Journal of Oceanology and Limnology 2024年第2期42卷 390-407页

作者： Weichen XIE tao WANG Wensheng jiang Key Laboratory of Marine Environment and Ecology Ocean University of ChinaQingdao 266100China College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266100China

Chlorophyll-a(Chl-a)concentration is a primary indicator for marine environmental *** spatio-temporal variations of sea surface Chl-a concentration in the Yellow Sea(YS)and the East China Sea(ECS)in 2001-2020 were investigated by reconstructing the MODIS Level 3 products with the data interpolation empirical orthogonal function(DINEOF)*** reconstructed results by interpolating the combined MODIS daily+8-day datasets were found better than those merely by interpolating daily or 8-day ***-a concentration in the YS and the ECS reached its maximum in spring,with blooms occurring,decreased in summer and autumn,and increased in late autumn and early *** performing empirical orthogonal function(EOF)decomposition of the reconstructed data fields and correlation analysis with several potential environmental factors,we found that the sea surface temperature(SST)plays a significant role in the seasonal variation of Chl a,especially during spring and *** increase of SST in spring and the upper-layer nutrients mixed up during the last winter might favor the occurrence of spring *** high sea surface temperature(SST)throughout the summer would strengthen the vertical stratification and prevent nutrients supply from deep water,resulting in low surface Chl-a *** sea surface Chl-a concentration in the YS was found decreased significantly from 2012 to 2020,which was possibly related to the Pacific Decadal Oscillation(PDO).

关键词： chlorophyll a(Chl a) data interpolation empirical orthogonal function(DINEOF) empirical orthogonal function(EOF)analysis Yellow Sea East China Sea

Study on a conical bearing for acceleration-sensitive equipment

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 103-128页

作者： Pang Hui Xu Wen Dai Junwu jiang tao Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbin 150080China Key Laboratory of Earthquake Disaster Mitigation Ministry of Emergency ManagementHarbin 150080China School of Civil Engineering and Transportation Beihua UniversityJilin 132013China

Seismic isolation effectively reduces seismic demands on building structures by isolating the superstructure from ground vibrations during ***,isolation strategies give less attention to acceleration-sensitive systems or ***,as the isolation layer’s displacement grows,the stiffness and frequency of traditional rolling and sliding isolation bearings increases,potentially causing self-centering and resonance *** a result,a new conical pendulum bearing has been selected for acceleration-sensitive equipment to increase self-centering capacity,and additional viscous dampers are incorporated to enhance system ***,the theoretical formula for conical pendulum bearings is supplied to analyze the device’s dynamic parameters,and shake table experiments are used to determine the proposed device’s isolation efficiency under various *** to the test results,the newly proposed devices have remarkable isolation performance in terms of minimizing both acceleration and displacement ***,a numerical model of the isolation system is provided for further research,and the accuracy is demonstrated by the aforementioned experiments.

关键词： seismic isolation acceleration-sensitive equipment the conical pendulum bearing shake table tests isolation performance,numerical model

Metal reflector-enhanced thermoacoustic imaging as a guidance for puncture biopsy

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Journal of Innovative Optical Health Sciences 2024年第6期17卷 83-96页

作者： Shuang Du tao Qiang Zihui Chi Huabei jiang School of Optoelectronic Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065P.R.China Department of Medical Engineering University of South FloridaTampaFL 33620USA

Puncture biopsy is an important clinical technique to obtain diseased tissue for pathological diagnosis,where imaging guidance is *** this paper,we describe a metal reflector-enhanced microwave-induced thermoacoustic imaging(TAI)approach capable of guiding puncture biopsy for detection of breast cancer and joint *** experimentations simulating puncture guidance in breast cancer and knee gout models werefirst conducted using(CST STUDIO SUITE)(CST)software,and then ex-vivo experiments were performed followed by qualitative observations and semi-quantitative *** results of both the simulations and ex-vivo experiments showed that our reflector-enhanced TAI could image the puncture needle in high resolution with a large depth of>12 cm.

关键词： Microwave-induced thermoacoustic imaging puncture guidance reflector

Assembly of peptide nanostructures with controllable sizes

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Nano Research 2024年第1期17卷 151-161页

作者： Dan Cheng Fan Jia Yun-Bao jiang Vincent P.Conticello tao jiang The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361005China Department of Chemistry Emory UniversityAtlanta 30033USA

Controlled peptide assembly offers significant promise to develop synthetic supramolecular nanostructures to display material and biological properties that mimic protein assemblies in *** the progress in forming peptide nanostructures of various morphology,there exists a distinct gap between natural and synthetic assembly systems in terms of size *** nanostructures with a narrow size distribution that can be tuned over a wide range of length-scales is essential for applications that require precise spacing between *** approach provides the opportunity to correlate materials and biological properties of interest with assembly *** this review,we discuss representative endeavors over the past two decades for design of size-controllable peptide nanostructures using tunable building *** mechanisms for size control,e.g.,molecular frustration,template-directed peptide assembly,and multi-component peptide co-assembly,will also be *** also demonstrate the applicable scopes of these strategies and suggest potential future avenues for scientific advances in this field.

关键词： peptide assembly controllable size template multi-component