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Numerical study of the deep removal of R134a from non-condensable gas mixture by cryogenic condensation and de-sublimation

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Chinese Journal of Chemical Engineering 2023年第9期61卷 180-191页

作者： Hongbo Tan Boshi Shao na Wen Department of Refrigeration and Cryogenic Engineering School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049China

Nowadays,the limits on greenhouse gas emissions are becoming increasingly *** present research,a two-dimensional numerical model was established to simulate the deep removal of 1,1,1,2-tetrafluoroethane(R134a)from the non-condensable gas(NCG)mixture by cryogenic condensation and *** wall condensation method was compiled into the Fluent software to calculate the condensation of R134a from the gas ***,the saturated thermodynamic properties of R134a under its triple point were extrapolated by the equation of *** simulation of the steam condensation with NCG was conducted to verify the validity of the model,the results matched well with the experimental ***,the condensation characteristics of R134a with NCG and the thermodynamic parameters affecting condensation were *** results show that the section with relatively higher removal efficiency is usually near the *** cold wall temperature has a great influence on the R134a removal performance,e.g.,a 15 K reduction of the wall temperature brings a reduction in the outlet R134a molar fraction by 85.43%.The effect of changing mass flow rate on R134a removal is mainly reflected at the outlet,where an increase in mass flow rate of 12.6% can aggravate the outlet molar fraction to 210.3% of the *** research can provide a valuable reference for the simulation of the deep removal of various low-concentration gas using condensation and de-sublimation methods.

关键词： Numerical simulation Greenhouse gas Condensation De-sublimation Vapor deep removal Non-condensable gas

Multi-Attribute Preferences Mining Method for Group Users with the Process of Noise Reduction

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Journal of Computer Science & Technology 2021年第4期36卷 944-960页

作者： Qing-Mei Tan Xu-na Wang College of Economic and Management Nanjing University of Aeronautics and AstronauticsNanjing 211106China Research Base for Civilian-Military Integration Development in Jiangsu Province Nanjing 211106China

Traditional researches on user preferences mining mainly explore the user’s overall preferences on the project,but ignore that the fundamental motivation of user preferences comes from their attitudes on some attributes of the *** addition,traditional researches seldom consider the typical preferences combination of group users,which may have influence on the personalized service for group *** solve this problem,a method with noise reduction for group user preferences mining is proposed,which focuses on mining the multi-attribute preference tendency of group ***,both the availability of data and the noise interference on preferences mining are considered in the algorithm *** the process of generating group user preferences,a new path is used to generate preference keywords so as to reduce the noise ***,the Gibbs sampling algorithm is used to estimate the parameters of the ***,using the user comment data of several online shopping websites as experimental objects,the method is used to mine the multi-attribute preferences of different *** proposed method is compared with other methods from three aspects of predictive ability,preference mining ability and preference topic *** results show that the method is significantly better thap other existing methods.

关键词： preferences mining group user multi-attribute noise reduction noise interference

Testing High-Dimensional Nonparametric Behrens-Fisher Problem

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Journal of Systems Science & Complexity 2022年第3期35卷 1098-1115页

作者： MENG Zhen LI na YUAN Ao Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Department of Biostatistics Bioinformatics and BiomathematicsGeorgetown UniversityWashington 20057USA

For high-dimensional nonparametric Behrens-Fisher problem in which the data dimension is larger than the sample size,the authors propose two test statistics in which one is U-statistic Rankbased Test(URT)and another is Cauchy Combination Test(CCT).CCT is analogous to the maximumtype test,while URT takes into account the sum of squares of differences of ranked samples in different dimensions,which is free of shapes of distributions and robust to *** asymptotic distribution of URT is derived and the closed form for calculating the statistical significance of CCT is *** simulation studies are conducted to evaluate the finite sample power performance of the statistics by comparing with the existing *** simulation results show that our URT is robust and powerful method,meanwhile,its practicability and effectiveness can be illustrated by an application to the gene expression data.

关键词： Cauchy combination test nonparametric Behrens-Fisher problem rank-based test U-statistic

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Partial Linear Model Averaging Prediction for Longitudinal data

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Journal of Systems Science & Complexity 2024年第2期37卷 863-885页

作者： LI na FEI Yu ZHANG Xinyu Faculty of Science Kunming University of Science and TechnologyKunming 650500China School of Statistics and Mathematics Yunnan University of Finance and EconomicsKunming 650221China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

Prediction plays an important role in data *** averaging method generally provides better prediction than using any of its *** though model averaging has been extensively investigated under independent errors,few authors have considered model averaging for semiparametric models with correlated *** this paper,the authors offer an optimal model averaging method to improve the prediction in partially linear model for longitudinal *** model averaging weights are obtained by minimizing criterion,which is an unbiased estimator of the expected in-sample squared error loss plus a *** properties,including asymptotic optimality and consistency of averaging weights,are established under two scenarios:(i)All candidate models are misspecified;(ii)Correct models are available in the candidate *** studies and an empirical example show that the promise of the proposed procedure over other competitive methods.

关键词： Asymptotic optimality longitudinal data model averaging estimator partially linear model prediction

DEM investigation of rock/bolt mechanical behaviour in pull-out tests

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Particuology 2020年第5期18卷 10-27页

作者： na Che Huaning Wang Mingjing Jiang School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Department of Oivil Engineering Tianjin UniversityTianjin 300072China

Rock bolt anchorage performance is crucial for tunnel support *** investigate the mechanical behaviour of reinforced rock and the bolts that reinforce it from the micro-scale to the *** pull-out tests were performed on soft rock using the distinct element method,in which a new contact model that considers bond size,is employed to constrain the main rock mechanical *** minimum sample width and height values for which the boundary effect can be neglected are first proposed through numerous tests on the influence of sample size on peak load and bond *** influence of sample width is substantially greater than that of sample *** then select an appropriate sample size to study the influence of bolt embedment length and confining pressure on the mechanical behaviours of the rock and *** results show that increased rock bolt embedment length and confining pressure can increase the peak load;however,the bolt length effect is limited when exceeding the critical anchorage *** cases without confining pressure,bond breakage occurs in the rock around the grout-rock interface and the breakage zone is rectangular,whereas in cases under confining pressure,the breakage zone presents an inverted cone *** use our results to discuss the influence of bond strength at the bolt-grout interface on the peak load and failure *** failure mode changes gradually from complex failure to single failure along the bolt-grout interface with decreasing interfacial bond strength.

关键词： Pull-out test Rock bolt Distinct element method Bolt embedment length Confining pressure

Effect of a Traffic Speed Based Cruise Control on an Electric Vehicle’s Performance and an Energy Consumption Model of an Electric Vehicle

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IEEE/CAA Journal of Automatica Sinica 2020年第2期7卷 386-394页

作者： Anil K.Madhusudhanan Xiaoxiang na Department of Engineering University of Cambridge

This paper proposes a cruise control system(CCS)to improve an electric vehicle's range,which is a significant hurdle in market penetration of electric vehicles.A typical driver or a conventional adaptive cruise control(ACC)controls an electric vehicle(EV)such that it follows a lead vehicle or drives close to the speed *** driving behaviour may cause the EV to cruise significantly above the average traffic *** may later require the EV to slow down due to the traffic ripples,wasting a part of the EV's kinetic *** addition,the EV will also waste higher speed dependent dissipative energies,which are spent to overcome the aerodynamic drag force and rolling *** paper proposes a CCS to address this *** proposed CCS controls an EV's speed such that it prevents the vehicle from speeding significantly above the average traffic *** addition,it maintains a safe inter-vehicular distance from the lead *** design and simulation analysis of the proposed CCS were in a MATLAB simulation *** simulation environment includes an energy consumption model of an EV,which was developed using data collected from an electric bus operation in *** the simulation analysis,the proposed system reduced the EV's energy consumption by approximately 36.6%in urban drive cycles and 15.4%in motorway drive ***,the experimental analysis using a Nissan e-NV200on two urban routes showed approximately 30.8%energy savings.

关键词： Cruise control electric vehicle(EV) energy performance safety traffic

Cobalt-catalyzed photopromoted carbonylation of chloroalkanes in the presence of KI

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Chinese Chemical Letters 2010年第9期21卷 1033-1036页

作者： Ying Ping Jia Ying na Cui Jing Mei Yin Guang Yun Zhou Shen Min Li da Bin Gao Xiang Sheng Wang State Key Laboratory of Fine Chemicals Dalian University of Technology. Dalian 116012 China Liaoning Key Laboratory of Bio-organic Chemistry Dalian University Dalian 116622China

The photopromoted carbonylation of chloroalkanes with carbon monoxide catalyzed by cobalt compounds[Co（OAc）2,CoCl2] in the presence of KI was carried out under ambient *** results revealed that the catalytic activity of Co（OAc）2 was higher than that of CoCl2.A basic additive naOAc was beneficial to the ***,with naOAc as an additive, Co（OAc）2 and CoCl2 exhibited similar catalytic *** work showed that the role of iodide ion was initially to form active iodoalkanes via substituting chloride ion in chloroalkanes in situ,and then,the carbonylation of iodoalkanes proceeded under irradiation.

关键词： Photopromoted carbonylation Chloroalkanes Cobalt complexes: KI

SYNTHESIS AND PROPERTIES OF BIFUNCTIOnaL MAGNETIC-OPTICAL naNOMATERiaLS:Fe_2O_3@PDMAEMA-CAPPED Ⅱ－Ⅵ SEMICONDUCTOR QUANTUM DOTS naNOCOMPOSITES

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Chinese Journal of Polymer Science 2013年第9期31卷 1233-1241页

作者： na-na Zhao Wei Nie Jun Mao Wei-cai Wang Xiang-ling Ji State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences

A facile route to synthesize a new type of multifunctional nanocomposites is reported. Here, PDMAEMA （poly[2- （dimethylamino）ethyl] methacrylate） is a key macromolecule serving as a bridge between magnetic FeaO3 nanoparticles and luminescent quantum dots. Both Fe203 nanoparticles and II-VI semiconductor quantum dots with a narrow size distribution are synthesized through a two-phase thermal approach. Subsequently, the atom transfer radical polymerization （ATRP） technique was applied to prepare magnetic Fe203@PDMAEMA core-shell nanoparticles. The thickness of PDMAEMA shell can be easily controlled by adjusting the reaction time. Finally, the ligand exchange method was exploited to modify II-VI quantum dot with amine-containing polymer of PDMAEMA, which led to quantum dot securely bound by Fe203@PDMAEMA core-shell nanoparticle to form a multifunctional nanocomposite. The resulting nanocomposite remains variable emission by tuning the II-VI semiconductor type and particle size and shows/arc at 49 kA/m and Tb at 16 K from Fe2O3 nanoparticles. The self-assembled behavior for the resulting samples is also discussed.

关键词： Bifunctional nanocomposite Magnetic-optical PDMAEMA Semiconductor ATRP Two-phase method.

Pollen Morphology of Eight Genera of the Subtribe Mutisiinae Less. sensu Bremer （Compositae） from Asia

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Journal of Integrative Plant Biology 2005年第9期47卷 1036-1046页

作者： na-na LIN Hong WANG De-Zhu LI Stephen BLACKMORE Laboratory of Biodiversity and Plant Biogeography Kunming Institute of Botany the Chinese Academy of Sciences Kunming 650204 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China Royal Botanic Garden Edinburgh Edinburgh EH3 5LR Scotland UK

The pollen morphology of 28 species and one variety representing eight genera of the subtribe Mutisiinae Less. sensu Bremer （Compositae） was investigated by scanning electron microscopy （SEM） and light microscopy. The pollen grains are usually radically symmetrical, isopolar, and tricolporate. The shape varies from spheroidal to subprolate in equatorial view and is three-lobed circular in polar view. Based on exine sculpturing observed under SEM, the pollen grains can be divided into three types：（i） type Ⅰ, with macrogranulate sculpture; （ii） type Ⅱ, with a finely granulate sculpture; and （iii） type Ⅲ with spiny sculpture. The palynological data showed that the Macroclinidium Maxim. was remarkably distinguished from those of the other seven genera. The variation of pollen characteristics within the Mutisiinae in Asia is little at species level, but it proves some useful information for studying the relationships among genera and it has an important significance in further understanding the evolutionary history of Mutisiinae.

关键词： Asia Compositae Mutisiinae pollen morphology.