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Numerical simulations for radon migration and exhalation behavior during measuring radon exhalation rate with closed-loop method

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Nuclear Science and Techniques 2024年第1期35卷 81-95页

作者： ming xia yong-Jun Ye Shu-Yuan Liu School of Resources Environment and Safety Engineering University of South ChinaHengyang 421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang 421001China

Accurate measurements of the radon exhalation rate help identify and evaluate radon risk regions in the *** these measurement methods,the closed-loop method is frequently ***,traditional experiments are insufficient or cannot analyze the radon migration and exhalation patterns at the gas–solid interface in the accumulation *** CFD-based technique was applied to predict the radon concentration distribution in a limited space,allowing radon accumulation and exhalation inside the chamber intuitively and *** this study,three radon exhalation rates were defined,and two structural ventilation tubes were designed for the *** consistency of the simulated results with the variation in the radon exhalation rate in a previous experiment or analytical solution was *** effects of the vent tube structure and flow rate on the radon uniformity in the chamber;permeability,insertion depth,and flow rate on the radon exhalation rate and the effective diffusion coefficient on back-diffusion were *** on the results,increasing the inser-tion depth from 1 to 5 cm decreased the effective decay constant by 19.55%,whereas the curve-fitted radon exhalation rate decreased(lower than the initial value)as the deviation from the initial value increased by approximately 7%.Increasing the effective diffusion coefficient from 2.77×10^(-7) to 7.77×10^(-6) m^(2) s^(-1) made the deviation expand from 2.14 to 15.96%.The conclusion is that an increased insertion depth helps reduce leakage in the chamber,subject to notable back-diffusion,and that the closed-loop method is reasonably used for porous media with a low effective diffusion coefficient in view of the back-diffusion *** CFD-based simulation is expected to provide guidance for the optimization of the radon exhalation rate measurement method and,thus,the accurate measurement of the radon exhalation rate.

关键词： Radon exhalation Numerical simulation Accumulation chamber

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Long-term effect of prophylactic laser treatment for bilateral soft drusen

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Chinese Medical Journal 2011年第4期124卷 541-545页

作者： HUANG Ying-xiang xiaNG Li-nan WANG Yan-ling LI ming-min HU yong-xia Department of Ophthalmology Beijing Friendship HospitalCapital Medical University Beijing 100050 China

Background Large drusen is a known risk factor for the development of late complications of age-related macular degeneration （AMD） and drusen reduction has been found by our previous study. To prospectively evaluate the efficacy and safety of prophylactic laser treatment in Chinese patients with bilateral soft drusen, we examined the structure and function of the macula 8 years after *** Ten patients with more than 10 soft drusen （〉125 mm） and best corrected visual acuity 〉20/25 in each eye participated in the study. One eye, with relatively more drusen, was exposed to an argon laser （514 nm） to achieve a barely visible retinal lesion. The contralateral eye was used as a control. Fluorescein angiography, Amsler tests,Fourier-domain optical coherence tomography and visual evoked potential tests were carried out 8 years *** No choroidal neovascularization was seen in the laser-treated eyes or control eyes. There were no significant differences in visual acuity or P100 latency and amplitude between the laser treated eyes and contralateral eyes （t=1.685,1.184; P〉0.05）. The thickness of the retinal pigment epithelium of the treated eyes was less than that of the contralateral eyes （t=-4.540; P 〈0.05）. The full retinal thickness in treated eyes was slightly, but insignificantly, reduced relative to contralateral eyes （t=-1.746; P 〉0.05）.Conclusions The treatment was associated with a reduction in retinal pigment epithelium thickness elevation compared with the contralateral eyes. Macular function was not impaired.

关键词： drusen prophylactic laser treatment macular thickness

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In-situ measurement via the flow-through method and numerical simulations for radon exhalation during measurements of the radon exhalation rate

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Nuclear Science and Techniques 2024年第7期35卷 192-207页

作者： ming xia yong-Jun Ye Shan-Wei Shang Ting Yu Dai-Jia Chen School of Resources Environment and Safety Engineering University of South ChinaHengyang421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang421001China

Small-scale measurements of the radon exhalation rate using the flow-through and closed-loop methods were conducted on the surface of a uranium tailing pond to better understand the differences between the two *** abnormal radon exhalation behavior was observed,leading to computational fluid dynamics(CFD)-based simulations in which dynamic radon migration in a porous medium and accumulation chamber was *** on the in-situ experimental and numerical simulation results,variations in the radon exhalation rate subject to permeability,flow rate,and insertion depth were quantified and *** in-situ radon exhalation rates measured using the flow-through method were higher than those measured using the closed-loop method,which could be explained by the negative pressure difference between the inside and outside of the chamber during the *** consistency of the variations in the radon exhalation rate between the experiments and simulations suggests the reliability of CFD-based techniques in obtaining the dynamic evolution of transient radon exhalation rates for diffusion and convection at the porous medium-air *** synergistic effects of the three factors(insertion depth,flow rate,and permeability)on the negative pressure difference and measured exhalation rate were quantified,and multivariate regression models were established,with positive correlations in most cases;the exhalation rate decreased with increasing insertion depth at a permeability of 1×10^(−11) m^(2).CFD-based simulations can provide theoretical guidance for improving the flow-through method and thus achieve accurate measurements.

关键词： Radon exhalation Flow-through Numerical simulation Accumulation chamber Multivariate regression

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Improvement of strength and ductility of Al-Cu-Li alloy through cryogenic rolling followed by aging

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Transactions of Nonferrous Metals Society of China 2017年第9期27卷 1920-1927页

作者： Yan-jun DENG Guang-jie HUANG Ling-fei CAO xiao-dong WU Li HUANG ming-yong xia Qing LIU College of Materials Science and Engineering Chongqing University Chongqing 400044 China

To develop an improved approach in achieving an excellent combination of high strength and ductility,the solutionized Al?Cu?Li plates were subjected to rolling at cryogenic and room temperatures,respectively,to a reduction of83%,followed by aging treatment at160°*** results indicate that Al?Cu?Li alloys through cryogenic rolling followed by aging treatment possess better mechanical *** at cryogenic temperature produces a high density of dislocations because of the suppression of dynamic recovery,which in turn promotes the precipitation of T1(Al2CuLi)precipitates during *** high density of T1precipitates enable effective dislocation pinning,leading to an increase in strength and *** contrast,room temperature rolled alloys after aging treatment exhibit lower strength and ductility due to low density of T1precipitates in the grain interior and high density of T1precipitates around subgrain boundaries.

关键词： Al-Cu-Li alloy cryogenic rolling dislocation T1 precipitate

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Highly Thermally Conductive Polydimethylsiloxane Composites with Controllable 3D GO@f-CNTs Networks via Self-sacrificing Template Method

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Chinese Journal of Polymer Science 2024年第7期42卷 897-906,I0005页

作者： Shuang-Shuang Wang Dian-Ying Feng Zhi-ming Zhang xia Liu Kun-Peng Ruan yong-Qiang Guo Jun-Wei Gu Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an710072China Shandong Institute of Nonmetallic Materials Jinan250031China Queen Mary University of London Engineering School Northwestern Polytechnical UniversityXi’an710072China

Constructing controllable thermal conduction networks is the key to efficiently improve thermal conductivities of polymer *** this work,graphite oxide(GO)and functionalized carbon nanotubes(f-CNTs)are combined to prepare“Line-Plane”-like hetero-structured thermally conductive GO@f-CNTs fillers,which are then performed to construct controllable 3D GO@f-CNTs thermal conduction networks via selfsacrificing template method based on oxalic ***,thermally conductive GO@f-CNTs/polydimethylsiloxane(PDMS)composites are fabricated via casting *** the size of oxalic acid is 0.24 mm and the volume fraction of GO@f-CNTs is 60 vol%,GO@f-CNTs/PDMS composites present the optimal thermal conductivity coefficient(λ,4.00 W·m^(-1)·K^(-1)),about 20 times that of theλof neat PDMS(0.20 W·m^(-1)·K^(-1)),also much higher than theλ(2.44 W·m^(-1)·K^(-1))of GO/f-CNTs/PDMS composites with the same amount of randomly dispersed ***,the obtained GO@f-CNTs/PDMS composites have excellent thermal stability,whoseλdeviation is only about 3%after 500 thermal cycles(20-200℃).

关键词： Polydimethylsiloxane Hetero-structured thermally conductive fillers Self-sacrificing template Thermal conduction networks

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Trotter–Kato Approximations of Impulsive Neutral SPDEs in Hilbert Spaces

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1229-1243页

作者： ming LIU xia ZHANG Ling Fei DAI School of Mathematical Sciences Tiangong UniversityTianjin 300387P.R.China

This paper studies a class of impulsive neutral stochastic partial differential equations in real Hilbert *** main goal here is to consider the Trotter-Kato approximations of mild solutions of such equations in the pth-mean(p≥2).As an application,a classical limit theorem on the dependence of such equations on a parameter is *** novelty of this paper is that the combination of this approximating system and such equations has not been considered before.

关键词： Impulsive neutral stochastic partial diferential equation Trotter-Kato approximations classical limit theorem

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Multi-field Split Curvature Wavefront Sensing and its Application in the Large Field Survey Telescope

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Research in Astronomy and Astrophysics 2024年第8期24卷 60-74页

作者： Zhixu Wu Yiming Zhang Jianan Cong Hua Bai yong xia Rongxin Tang ming Li Zhengyang Li xiangyan Yuan Institute of Space Science and Technology Nanchang UniversityNanchang 330031China Nanjing Institute of Astronomical Optics&Technology CASNanjing 210042China University of Chinese Academy of Sciences NanjingNanjing 211135China

The image quality of a large field survey telescope with a fast focal ratio of the primary mirror is high sensitivity to the optical elements’misalignments and the primary mirror’s *** maintain good optical performance,the perturbations need to be aligned,and the tomographic reconstruction of these perturbations can be derived from wavefront sensing with multi-field points for *** work undertakes a comprehensive examination related to the implementation and optimization of a multi-field split curvature wavefront sensing system,including defocus distance,signal pre-processing,deblending of overlapped doughnuts,field-dependent correction,and distorted coordinate *** also conduct experiments to demonstrate the application and performance of a multi-field split curvature wavefront sensing system in *** the context of the decentering of the secondary mirror,the coefficient of determination(R)attains a high value of 0.993,indicating a robust linearity between the coma coefficients and the decentering of the secondary mirror.A comparative analysis of the simulated and experimental results shows that the difference between them is less than 0.1λ.

关键词： Instrumentation high angular resolution-Techniques photometric-Techniques image processing

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On the Strong Approximation for a Simple Reentrant Line in Light Traffic Under First-buffer First-served Service Discipline

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 823-839页

作者： Kai-ming YANG yong-jiang GUO School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China

For a 2-station and 3-class reentrant line under first-buffer first-served(FBFS)service discipline in light traffic,we firstly construct the strong approximations for performance measures including the queue length,workload,busy time and idle time *** on the obtained strong approximations,we use a strong approximation method to find all the law of the iterated logarithms(LILs)for the above four performance measures,which are expressed as some functions of system parameters:means and variances of interarrival and service times,and characterize the fluctuations around their fluid approximations.

关键词： reentrant line queueing network FBFS service discipline strong approximation LIL Brownian motion

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Heterointerface Engineering-Induced Oxygen Defects for the Manganese Dissolution Inhibition in Aqueous Zinc Ion Batteries

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Energy & Environmental Materials 2024年第3期7卷 112-122页

作者： Wentao Qu yong Cai Baohui Chen ming Zhang Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics&Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China Engineering Research Center of Advanced Semiconductor Technology and Application of Ministry of Education&Key Laboratory for Micro-/Nano-Optoelectronic Devices of Ministry of Education College of Semiconductors(College of Integrated Circuits)Hunan UniversityChangsha 410082China Changsha Semiconductor Technology and Application Innovation Research Institute College of Semiconductors(College of Integrated Circuits)Hunan UniversityChangsha 410082China State Key Laboratory of Disaster Prevention&Reduction for Power Grid Transmission and Distribution Equipment(Hunan Electric Power Corporation Disaster Prevention and Reduction Center) Changsha 410007China

Manganese-based material is a prospective cathode material for aqueous zinc ion batteries(ZIBs)by virtue of its high theoretical capacity,high operating voltage,and low ***,the manganese dissolution during the electrochemical reaction causes its electrochemical cycling stability to be *** this work,heterointerface engineering-induced oxygen defects are introduced into heterostructure MnO_(2)(δa-MnO_(2))by in situ electrochemical activation to inhibit manganese dissolution for aqueous zinc ion ***,the heterointerface between the disordered amorphous and the crystalline MnO_(2)ofδa-MnO_(2)is decisive for the formation of oxygen *** the experimental results indicate that the manganese dissolution ofδa-MnO_(2)is considerably inhibited during the charge/discharge *** analysis indicates that the oxygen defect regulates the electronic and band structure and the Mn-O bonding state of the electrode material,thereby promoting electron transport kinetics as well as inhibiting Mn ***,the capacity ofδa-MnO_(2)does not degrade after 100 cycles at a current density of 0.5 Ag^(-1)and also 91%capacity retention after 500cycles at 1 Ag^(-1).This study provides a promising insight into the development of high-performance manganese-based cathode materials through a facile and low-cost strategy.

关键词： electrochemical activation heterointerface manganese dissolution inhibition oxygen defects zinc ion batteries

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Data-driven Anomaly Detection Method Based on Similarities of Multiple Wind Turbines

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 803-818页

作者： xiangjun Zeng ming Yang Chen Feng mingqiang Wang Lingqin xia the College of Electrical Engineering&New Energy China Three Gorges UniversityYichang 443002China the Key Laboratory of Power System Intelligent Dispatch and Control Shandong UniversityJinan 250061China

The operating conditions of wind turbines(WTs)in the same wind farm(WF)may share similarities due to their shared manufacturing process,control strategy,and operating ***,the similarities of WTs are seldom considered in WT anomaly detection,resulting in the disregard of useful *** paper proposes a method to improve the reliability and accuracy of WT anomaly detection using the supervisory control and data acquisition(SCADA)data of multiple WTs in the same ***,a similarity assessment method based on a comparison of different observation time series is proposed,which objectively quantifies the similarities of WT operating ***,the SCADA data of the target WT and selected WTs that are similar are used to establish several estimation models through a long short-term memory(LSTM)*** models that exhibit good estimation performance are used to construct a combined estimation model that estimates the variations in the monitored variables of the target ***,an anomaly detection method that jointly compares the effective value and information entropy of the residuals is proposed to identify *** effectiveness and accuracy of the proposed method are verified using the data of two actual WFs.

关键词： Anomaly detection information entropy long short-term memory similarity assessment wind farm wind turbines

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