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Journal of Systems Science & Complexity 2015年第6期28卷 1344-1362页

作者： TANG Zhipeng xia Yan Key Laboratory of Regional Sustainable Development Modeling Institute of Geography Sciences and Natural Resources Research Chinese Academy of Sciences Center for Energy and Environmental Policy Research Institute of Policy and Management Chinese Academy of Sciences

This paper provides an extended input-occupancy-output analysis of wastewater discharge coeffcients, as well as backward and forward linkages of Chinese multi-regional industrial sectors in2007. The results show that the direct and total industrial wastewater discharge coeffcients of most of the provincial industrial sectors in China＇s Eastern region are lower than those of the whole *** backward and forward linkages of fixed-asset occupancy in industrial sectors in China＇s Central and Western regions are strong. The dissimilarity of cross-sectional data of the relevant industrial wastewater discharge coeffcients and linkages in multi-regional input-output analysis becomes bigger as regions are divided more extensively.

关键词： Backward linkage forward linkage industrial wastewater discharge input-occupancyoutput analysis

Validation of MODIS and Deep Blue aerosol optical depth retrievals in an arid/semi-arid region of northwest China

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Particuology 2012年第1期10卷 132-139页

作者： xia Li xiangao xia Shengli Wang Jietai Mao Yan Liu LAGEO Institute of Atmospheric Physics ChineseAcademy of Sciences Beijing 100029 China Institute of Desert Meteorology China Meteorology Administration Urumqi 830002 China Xinjiang Climate Center Urumqi 830002 China School of Physics Peking University Beil＇ing 100871 China

The global aerosol optical depth （AOD or r） has been retrieved using the Dark Target algorithm （the C004 and C005 products） and the Deep Blue algorithm （DB product）. Few validations have thus far been performed in arid/semi-arid regions, especially in northwest China. The ground-based remote sensing of AOD from sun photometers at four sites in Xinjiang during the years 2002-2003 is used to validate aerosol products, including C004, C005 and DB of the Moderate Resolution Imaging Spectroradiometer （MODIS）. The results show substantial improvement in the C005 aerosol product over the C004 product. The average correlation coefficient of regression with ground measurements increased from 0.59 to 0.69, and the average offset decreased from 0.28 to 0.13. The slopes of the linear regressions tended to be close to unity. The percentage of AODs falling within the retrieval errors of 30% （or Δτ = ±0.1 ± 0.2τ） increased from 16.1% to 45.6%. The best retrievals are obtained over an oasis region, whereas the worst are obtained over urban areas. Both the MODIS C004 and C005 products overestimate AOD, which is likely related to improper assumptions of the aerosol model and of the estimation of surface reflectance. An encouraging result has been derived with regard to validation of the DB AOD. Overall, the average offset, slope and correlation coefficient of regression with sun-photometer measurements are -0.04, 0.88 and 0.85, respectively. Approximately 73% of the DB AOD retrievals fall within the expected error of 30%. Underestimation of the AOD by the DB products is observed. The aerosol model and estimations of surface reflectance in this region require further improvements.

关键词： MODISSun-photometerAerosol optical depthDeep blue algorithm

Grey Relation between Nonlinear Characteristic and Dynamic Uncertainty of Rolling Bearing Friction Torque

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Chinese Journal of Mechanical Engineering 2009年第2期22卷 244-249页

作者： xia Xintao WANG Zhongyu College of Mechatronical Engineering Henan University of Science and Technology Luoyang 4 71003 China College of Instrumental Science and Optoelectronics Engineering Beijing University of Aeronautics and Astronautics Beijing 100191 China

The rolling bearing friction torque which is characterized by its uncertainty and nonlinearity affects heavily the dynamic performance of a system such as missiles, spacecrafts and radars, etc. It is difficult to use the classical statistical theory to evaluate the dynamic evaluation of the rolling bearing friction torque for the lack of prior information about both probability distribution and trends. For this reason, based on the information poor system theory and combined with the correlation dimension in chaos theory, the concepts about the mean of the dynamic fluctuant range （MDFR） and the grey relation are proposed to resolve the problem about evaluating the nonlinear characteristic and the dynamic uncertainty of the rolling bearing friction torque. Friction torque experiments are done for three types of the rolling bearings marked with HKTA, HKTB and HKTC separately; meantime, the correlation dimension and MDFR are calculated to describe the nonlinear characteristic and the dynamic uncertainty of the friction torque, respectively. And the experiments reveal that there is a certain grey relation between the nonlinear characteristic and the dynamic uncertainty of the rolling bearing friction torque, viz. MDFR will become the nonlinear increasing trend with the correlation dimension increasing. Under the condition of fewer characteristic data and the lack of prior information about both probability distribution and trends, the unitive evaluation for the nonlinear characteristic and the dynamic uncertainty of the rolling bearing friction torque is realized with the grey confidence level of 87.7%-96.3%.

关键词： rolling bearing friction torque time series correlation dimension mean of dynamic fluctuant range (MDFR),information poor system theory

Exploration and progress of high-energy supercapacitors and related electrode materials

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Science China(Technological Sciences) 2015年第11期58卷 1851-1863页

作者： YANG Mei xia Hui School of Materials Science and Engineering Nanjing University of Science and Technology Herbert Gleiter Institute of Nanoscience Nanjing University of Science and Technology

As one of new electrical energy storage systems, supercapacitors possess higher energy density than conventional capacitors and larger power density than batteries, integrating substantial merits with high energy, large power delivery, long cycle life, obvious safety, and low cost. However, the unsatisfying energy density is the inhabiting issue for the wide commercial applications. As the energy density(E, W h kg?1) is directly proportional to specific capacitance(C, F g?1) and the square of operating voltage(V, V), in this review, we summarize the recent progress in two sections: the exploration of high-performance electrode materials to achieve high specific capacitance and the construction of high-voltage supercapacitor systems for high working voltage. The progressive explorations and developments in supercapacitors could guide the future research towards high-performance, low-cost, and safe energy storage devices.

关键词： electrochemical capacitors high-energy supercapacitors electrode materials energy density energy storage systems

Effects of assembly errors and bonding defects on the centroid drift of a precision sleeve structure

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Advances in Manufacturing 2021年第4期9卷 509-519页

作者： Jian-Hua Liu xia-Yu Li Huan-Xiong xia Lei Guo School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081People’s Republic of China

Adhesive joints are widely used in precision electromechanical products,and their bonding process has significant effects on the performance of an assembled *** paper presents a numerical study on the bonding assembly of a sleeve structure of a precision inertial device using a finite element method,where the stresses due to curing and relaxation behaviors are *** effects of assembly errors and bonding defects on the centroid drift of the sleeve structure were found and analyzed *** study can help understand the zero-drift mechanism of the precision inertial device and contribute valuable data for its error compensation.

关键词： Bonding process Adhesive joint Precision assembly Centroid drift

Early stage toxicity of excess copper to photosystem II of Chlorella pyrenoidosa–OJIP chlorophyll a fluorescence analysis

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Journal of Environmental Sciences 2009年第11期21卷 1569-1574页

作者： xia Jianrong TIAN Qiran School of Environmental Science and Engineering Guangzhou University Guangzhou 510006 China Marine Biology Institute Shantou University Shantou Guangdong 515063 China

Acute toxicity of excess Cu on the photosynthetic performance of Chlorella pyrenoidosa was examined by using chlorophyll a fluorescence transients and JIP-test after exposure to elevated Cu concentrations for a short time period. High Cu concentration resulted in a significant suppression in photosynthesis and respiration. The absorption flux （ABS/RC） per PSII reaction center increased with increasing Cu concentration, but the electron transport flux （ET0/RC） decreased. Excess Cu had an insignificant effect on the trapping flux （TR0/RC）. The decline in the efficiency, with which a trapped exciton can move an electron into the electron transport chain further than QA-（Ψ0）, the maximal quantum yield of primary photochemistry （φP0）, and the quantum yield of electron transport （φE0） were also observed. The amount of active PSII reaction centers per excited cross section （RC/CS） was also in consistency with the change of photosynthesis when cells were exposed to excess Cu concentration. JIP-test parameters had a good linear relationship with photosynthetic O2 evolution. These results suggested that the decrease of photosynthesis in exposure to excess Cu may be a result of the inactivation of PSII reaction centers and the inhibition of electron transport in the acceptor side.

关键词： Chlorella pyrenoidosa chlorophyll a fluorescence Cu PSII

Boundary-layer transition prediction using a simplified correlation-based model

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Chinese Journal of Aeronautics 2016年第1期29卷 66-75页

作者： xia Chenchao Chen Weifang School of Aeronautics and Astronautics Zhejiang University

This paper describes a simplified transition model based on the recently developed correlation-based γ - Reot transition model. The transport equation of transition momentum thick- ness Reynolds number is eliminated for simplicity, and new transition length function and critical Reynolds number correlation are proposed. The new model is implemented into an in-house com- putational fluid dynamics （CFD） code and validated for low and high-speed flow cases, including the zero pressure flat plate, airfoils, hypersonic flat plate and double wedge. Comparisons between the simulation results and experimental data show that the boundary-layer transition phenomena can be reasonably illustrated by the new model, which gives rise to significant improvements over the fully laminar and fully turbulent results. Moreover, the new model has comparable features of accuracy and applicability when compared with the original 3＇ - Reot model. In the meantime, the newly proposed model takes only one transport equation of intermittency factor and requires fewer correlations, which simplifies the original model greatly. Further studies, especially on separation- induced transition flows, are required for the improvement of the new model.

关键词： Boundary-layer transition Computational fluiddynamics Correlation Transition model Turbulence model

Performance Analysis of ACO on the Quadratic Assignment Problem

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Chinese Journal of Electronics 2018年第1期27卷 26-34页

作者： xia xiaoyun ZHOU Yuren College of Mathematics Physics and Information Engineering Jiaxing University School of Data and Computer Science Sun Yat-sen University

The Quadratic assignment problem(QAP)is to assign a set of facilities to a set of locations with given distances between the locations and given flows between the facilities such that the sum of the products between flows and distances is minimized, which is a notoriously difficult NP-hard combinatorial optimization problem. A lot of heuristics have been proposed for the QAP problem, and some of them have proved to be efficient approximation algorithms for this problem. Ant colony optimization(ACO) is a general-purpose heuristic and usually considered as an approximation algorithms for NP-hard optimization problems. However, we know little about the performance of ACO for QAP from a theoretical perspective. This paper contributes to a theoretical understanding of ACO on the QAP problem. The worst-case bound on a simple ACO algorithm called(1+1) Max-min ant algorithm((1+1) MMAA) for the QAP problem is *** is shown that a degenerate(1+1) MMAA finds an approximate solution on the QAP problem. Finally, we reveal that ACO can outperform the 2-exchange local search algorithm on an instance of the QAP problem.

关键词： Ant colony optimization(ACO) Quadratic assignment problem(QAP) Approximation algorithms Local search Algorithms analysis Runtime analysis

Semi-permeable Yoffe-type interfacial crack analysis in MEE composites based on the strip electro-magnetic polarization saturation model

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Acta Mechanica Solida Sinica 2017年第4期30卷 354-368页

作者： xiaodong xia Zheng Zhong School of Aerospace Engineering and Applied Mechanics Tongji University School of Science Harbin Institute of Technology

Fracture analysis of a semi-permeable Yoffe-type interfacial crack propagating subsonically in magneto-electro-elastic （MEE） composites is presented based on the strip electro- magnetic polarization saturation （SEMPS） model. The electro-magnetic fields inside the crack are considered under the semi-permeable boundary condition. Nonlinear effects near the interfacial crack tip are represented by different electro-magnetic saturation zones. Utilizing the extended Stroh＇s method, we derive the moving dislocation densities as well as intensity factor and energy release rate for Yoffe-type MEE interracial crack. Numerical re- sults through an iterative approach are presented to show the characteristics of fracturedominant parameters with respect to propagation velocity and boundary condition category. The fracture-dominant parameters under the semi-permeable boundary condition are lower than those under the impermeable one, which implies that the electro-magnetic fields in the crack gap can retard the propagation of MEE interfacial crack.

关键词： Yoffe-type interracial crack Semi-permeable boundary condition Polarization saturation Fracture toughness Magneto-electro-elastic

Minimum mass-entransy dissipation profile for one-way isothermal diffusive mass-transfer process with mass-resistance and massleakage

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Science China(Technological Sciences) 2024年第8期67卷 2427-2435页

作者： CHEN LinGen xia ShaoJun Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China School of Mechanical Electrical EngineeringWuhan Institute of TechnologyWuhan 430205China School of Power Engineering Naval University of EngineeringWuhan 430033China

As a new concept,mass-entransy is one of the twins in the core of entransy *** can describe mass-transfer ability for masstransfer processes(MTPes),just as thermal-entransy for describing heat-transfer ***,mass-entransy dissipation can be utilized to evaluate the loss of mass-transfer *** mass-entransy dissipation(MMED) is utilized to optimize one-way isothermal diffusive MTPes with mass-leakage and mass-transfer law(g ∝ Δ(c),where c means concentration).For a given net amount of mass-transferred key components at the low-concentration side,optimality-condition for the MMED of isothermal diffusive MTPes is obtained by using the *** of the amount of mass-transferred and mass-leakage on optimal results are analyzed,and the obtained optimization profiles are compared with those for MTP profiles of constant-concentration-difference(c_1-c_2=const) and constant-concentration-ratio(c_1/c_2=const).The product of square of key-component-concentration(KCC) difference between high-and low-concentration sides and inert component concentration at high-concentration side for the MMED of the MTP with no mass-leakage is a constant,and the optimal relationship of the KCCs between high-and low-concentration sides with mass-leakage is significantly different from the *** mass-leakage is relatively small,the MTP with c_1-c_2=const strategy is superior to that with c_1/c_2=const strategy,and the latter is superior to the former with an increase in mass-leakage.A combination of mass-entransy concept,finite-time thermodynamics,and averaged-optimization-method is a meaningful tool for optimizing MTPes.

关键词： diffusive mass-transfer-law mass-leakage one-way isothermal mass-transfer minimum mass-entransy dissipation finite-time thermodynamics averaged-optimization-method