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An equivalent ground thermal test method for single-phase fluid loop space radiator

Chinese Journal of Aeronautics 2015年第1期28卷 86-92页

作者： Ning Xianwen Wang Yuying Zhang jiaxun Liu Dongxiao Beijing Key Laboratory of Space Thermal Control Technology Beijing Institute of Spacecraft System Engineering (ISSE)

Thermal vacuum test is widely used for the ground validation of spacecraft thermal control system. However, the conduction and convection can be simulated in normal ground pressure environment completely. By the employment of pumped fluid loops＇ thermal control technology on spacecraft, conduction and convection become the main heat transfer behavior between radiator and inside cabin. As long as the heat transfer behavior between radiator and outer space can be equivalently simulated in normal pressure, the thermal vacuum test can be substituted by the normal ground pressure thermal test. In this paper, an equivalent normal pressure thermal test method for the spacecraft single-phase fluid loop radiator is proposed. The heat radiation between radiator and outer space has been equivalently simulated by combination of a group of refrigerators and thermal electrical cooler（TEC） array. By adjusting the heat rejection of each device, the relationship between heat flux and surface temperature of the radiator can be maintained. To verify this method,a validating system has been built up and the experiments have been carried out. The results indicate that the proposed equivalent ground thermal test method can simulate the heat rejection performance of radiator correctly and the temperature error between in-orbit theory value and experiment result of the radiator is less than 0.5 C, except for the equipment startup period. This provides a potential method for the thermal test of space systems especially for extra-large spacecraft which employs single-phase fluid loop radiator as thermal control approach.

关键词： spacecraft rejection orbit conduction branch pumped employment convection outer correctly

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Pricing Binary Variables of System-wide Constraints for Power System Optimization

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1131-1144页

作者： jiaxun Li Wei Lin Zhifang Yang Mikhail Davidson State Key Laboratory of Power Transmission Equipment and System Security and New Technology College of Electrical EngineeringChongqing UniversityChongqing 400030China Department of Electrical Engineering The Hong Kong Polytechnic UniversityHong Kong SAR 999077China Faculty of Computational Mathematics and Cybernetics Moscow State UniversityMoscow 119991Russia IEEE

With the trend of multiple energies or flexible demand in power systems,binary variables appear in systemwide constraints,which are the foundation of marginal pricing currently in *** appropriate pricing method incentivizes compliance of market participants;otherwise,compliance can be incentivized by paying discriminatory uplift payments which jeopardize transparency of *** paper proposes two theorems to examine whether the binary variables brought by multiple energies and flexible demand will impact compliance under marginal *** first theorem shows sufficient conditions with which marginal pricing with fixed binary variables incentivizes compliance,while the second theorem shows sufficient conditions to require uplift *** improve transparency by reducing uplift payments under cases which fall into the second theorem,this paper further proposes a pricing method by combining 1)designed constraints to price binary variables in system-wide constraints,and 2)convex hull pricing to price binary variables in private *** of the proposed theorems and pricing method is verified in an electricity-gas case(consisting of the IEEE 30-bus system and the NGS 10-node system)and the IEEE 118-bus test system.

关键词： Binary variables impact analysis pricing under non-convexities

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Theoretical Analysis on the Air-Condition Cabin Technique for Satellite Temperature Adjustment on the Ground

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Journal of Thermal Science 2004年第1期13卷 80-84页

作者： jiaxun Zhang Sujun Yang Hongyan Ren Jindong Li Chinese Acad Space Technol Beijing 100086 Peoples R China

The aim of this paper is to study the heat transfer mechanism of the air-condition cabin technique for satellite temperature adjustment on the ground before the launch of those satellites with pressurized structure. By the study, the temperature of the satellite can be set appropriately, and this is very important to the initial satellite temperature after the satellite operates in orbit. In the paper, the simplified physical model is provided and the mathematical equations are obtained, thereafter, the experimental data are compared with the theoretical analysis. The quantitative conclusions from the theoretical analysis can be used to direct the design or the experiment of the temperature adjustment. Finally, we can conclude that, the temperature variation rule of the satellite is exponential, and the temperature adjustment process can be predicted by the exponential formula, which is obtained from the theoretical analysis.

关键词： thermal control spacecraft temperature adjustment on the ground.

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Refinement and Transformation from Z Specification to C+ +

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Journal of Donghua University(English Edition) 2001年第4期18卷 97-102页

作者： Zhang Xiaoying(张晓莺) Chen jiaxun(陈家训) Dept. of Computer Science and Engineering Dong Hua University Shanghai 200051 Dept. of Computer Science and Engineering Dong Hua University Shanghai 200051

As a kind of formal specification language, Z has gained a position in the field of software development, but there is still no standard way of transforming Z specification into executable code that is promising in increasing the quality, reusability and maintainability of *** the automatic programming model of software engineering, through the analysis for Z specification language, a feasible semi-automatic way of refinement and transformation is proposed, and the correctness of the procedure is also discussed.

关键词： Z specification refinement transformation C + + Class template Function template

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Detailed in-furnace measurements with reburning of superfine pulverized coal in high CO_(2)concentration

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Journal of Environmental Sciences 2021年第6期33卷 326-334页

作者： Jun Shen jiaxun Liu Shengxiang Deng Sha Wang Bin Chen Xiumin Jiang School of Mechanical and Automotive Engineering Shanghai University of Engineering ScienceShanghai 201620China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

This paper presents detailed measurements of gaseous species during the reburning process with high CO_(2)concentration in a bench-scale *** pulverized coal,with the average particle size below or around 20μm,is used as the reburning *** data of flue gas concentration(NOx,HCN,NH_(3),CH_(4),O_(2),CO,CO_(2)etc.)is obtained in order to reveal the intrinsic connection between NOx emissions and other influential gaseous species at different positions of the *** finding concludes that the advantage of superfine pulverized coal with regard to NO reduction is more efficient in homogeneous stage rather than heterogeneous ***,the evolution of HCN and CH_(4)agrees well with each stage of NO reduction,which indicates that these gaseous species are favorable for NO ***,oxygen consumption rate for superfine pulverized coal is relatively faster,conducive to strengthen both homogeneous and heterogeneous NO reduction under CO_(2)reburning condition.

关键词： NO reduction Superfine pulverized coal Coal combustion Reburning in CO_(2)

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Do trace metal(loid)s in road soils pose health risks to tourists?A case of a highly-visited national park in China

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Journal of Environmental Sciences 2022年第1期34卷 61-74页

作者： Jingling Huang Yuying Wu Yanyao Li jiaxun Sun Yujing Xie Zhengqiu Fan Department of Environmental Science and Engineering Fudan UniversityShanghai 200433China

Nowadays,more people tend to spend their recreational time in large national parks,and trace metal(loid)s in soils have attracted long-term attention due to their possible harm to human *** investigate the pollution levels,potential sources and health risks of trace metal(loid)s in road soils,a total of eight trace metal(loid)s(including As,Cd,Cr,Cu,Ni,Pb,Zn and Hg)from 47 soil samples along roads were studied in the Huangshan National Park in Southeast *** results showed that the concentrations of As,Cd,Pb,Zn and Hg appeared different degrees of pollution compared with their corresponding background *** to the pollution indices,Hg and Cd were recognized as significant pollutants presenting moderate to high ecological *** principal component analysis and positive matrix factorization model,the results showed that traffic,industrial,agricultural and natural sources were the potential origins of trace metal(loid)s in this area,with contribution rates of 39.93%,25.92%,10.53%and 23.62%,***-carcinogenic risks were all negligible,while the carcinogenic risk of As was higher than the limit(1×10^(-6)).Moreover,children were more susceptible to trace metal(loid)s by ingestion which appeared to be a more important exposure pathway than dermal contact and *** contribution rates of different sources to non-carcinogenic risks and carcinogenic risks were similar among children and adults,while traffic and industrial sources have a significant impact on health *** study will give more insights to control the environmental risks of trace metal(loid)s in national parks.

关键词： Trace metal(loid)s Pollution assessment Source apportionment Health risk assessment National park

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Absolute Configurational Assignments of Amino Acid Esters by a CD-Sensitive Malonamide-Linked Zinc Bisporphyrinate Host

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Chinese Journal of Chemistry 2014年第8期32卷 797-802页

作者： Baozhen Liu jiaxun Jiang Xianshi Fang Chuanjiang Hu Key Laboratory of Organic Synthesis of Jiangsu Province College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhouJiangsu 215123China State Key Lab&Coordination Chemistry Institute Nanjing UniversityNanjingJiangsu 210093China

A novel malonamide-linked zinc bisporphyrinate[Zn_(2)-1]has been designed and ***-vis and NMR spectroscopic studies suggest the molecule aggregates in *** zinc bisporphyrinate is very CD-sensitive when it is mixed with amino acid ethyl *** amplitude value of the induced circular dichroism(ICD)is up to ca.1500 L•mol^(−1)•cm^(−1).Further studies by ^(1)H NMR and UV-vis spectroscopies reveal amino acid esters function as monodentate ligands,and[Zn_(2)-1]interacts with amino acid ethyl esters through coordination and hydrogen bonding interactions.

关键词： bisporphyrin malonamide configurational assignment amino acid ester

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Impacts of land conversion and management measures on net primary productivity in semi-arid grassland

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Ecosystem Health and Sustainability 2020年第1期6卷 434-449,433页

作者： Feifei Cao jiaxun Li Xiao Fu Gang Wu State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijingChina University of Chinese Academy of Sciences BeijingChina

Ecological restoration measures implemented in China have profoundly impacted vegetation *** study aimed to estimate the effects of the land conversion and management measures on the grassland ecosystem in semi-arid *** use data were employed from 2000 to 2015 to compare land conversion and coverage changes in Xilingol ***,the contributions of land conversion and management policies were quantified by assessing the difference between actual NPP and climate-induced NPP *** results indicated that the grassland area had a net loss of 534.42 km^(2),and the net area of increased vegetation coverage was 74,683.05 km^(2).Furthermore,the total NPP increased by 8,010.73 Gg C·yr^(−1)(1 Gg=10^(9)g),of which the human activities,including grazing management measures(+6,809.40 Gg C·yr^(−1))and land conversion(45.72 Gg C·yr^(−1))contributed to 85.58%of the increase in *** from desert and farmland dominated grassland expansion and NPP increase,while urbanization and desertification caused large grassland reduction and NPP *** grazing management increased vegetation NPP in most regions except for some regions in the desert steppe and the farming-pastoral *** policies should be further adjusted to strengthen the management of the desert steppe and farming-pastoral regions.

关键词： Grassland degradation land use and land cover change management measures and policies net primary productivity(NPP) Xilingol grassland anthropogenic/human activities affects

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Characterizing the capability of mesoscale eddies to carry drifters in the northwest Pacific

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Journal of Oceanology and Limnology 2020年第6期38卷 1711-1728页

作者： WANG Huizan LIU Ding ZHANG Weimin LI jiaxun WANG Bo College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410073China Naval Research Academy Tianjin 300061China

Mesoscale eddies are common oceanic *** many related studies have been conducted,the ability for mesoscale eddies to carry real particles remains poorly *** considered the drifters as real particles to characterize the capability of mesoscale eddies to carry ***,mesoscale eddies in the northwest Pacific(99°E-180°E,0°-66°N)were identified using sea level anomaly(SLA)data from 1993 to ***,three important parameters(the carrying days,the number of circles the drifter revolving around the eddy center,and the carrying distances)were calculated by colocalizing eddy data with ***,statistical analysis and composite analysis were conducted,reflecting the capability of mesoscale eddies to carry *** mechanisms on the carrying capability of eddies were also *** show that(1)the motion of carried drifters reflects the upper limit of rotational speed of eddies that the drifters revolve around the eddy center by≤90°for one day in most cases;(2)the drifters tend to be carried for a longer time when their minimal distances to the eddy center measured with normalized distance are small;(3)there are two types of eddies(cyclonic and anticyclonic eddies)in different subregions of northwest Pacific,and each has a different carrying capability(on average,similar in the tropical ocean and Subtropical Countercurrent,cyclonic eddies tend to have stronger carrying capability in Southern Kuroshio Extension,and anticyclonic eddies tend to have stronger carrying capability in Northern Kuroshio Extension and Subarctic Gyre);(4)on average,the carried drifters tend to travel for a longer time around the normalized eddy radii ranging from 0.41 to 0.76;(5)the carrying days are related to the Rossby number of the eddy(in general when the Rossby number is smaller,the carrying days are longer).

关键词： mesoscale eddy drifter Rossby number composite analysis carrying capability

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Density functional and experimental study of NO/O2 on zigzag char

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Journal of Environmental Sciences 2020年第2期32卷 283-291页

作者： Jun Shen Hai Zhang jiaxun Liu Lei Luo Sha Wang Bin Chen Xiumin Jiang School of Mechanical and Automotive Engineering Shanghai University of Engineering and ScienceShanghai 201620China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China National Laboratory for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China

In this paper, quantum chemistry computation(density functional theory) of multi-airstaged combustion was investigated in combination with *** was found that the presence of oxygen in the combustion environment has a great influence on the surface chemistry of coal *** the reaction pathway, the ring-opening reaction happens first,and is followed by NO ***, the ring-closure reaction takes place, leaving the nitrogen atom trapped in the inner char *** reaction route effectively inhibits NO formation and achieves the aim of controlling NO *** the staged combustion experiments, the consumption of O2/NO was accompanied by an increase in the CO2 *** quantum chemistry computation successfully interprets the recent experimental trends displayed in multi-air-staged combustion.

关键词： Nitrogen oxide DFT study Coal combustion Heterogeneous reduction Char nitrogen

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