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Luminosity Limit of Super-Eddington Accretion onto Black Holes

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Chinese Physics Letters 1999年第6期16卷 467-468页

作者： WANG jian-min Department of Astronomy Beijing Normal UniversityBeijing 100875 Chinese Academy of Sciences-Peking University Joint Beijing Astrophysical Center Beijing 100871

The luminosity limit is derived for the super-Eddington accretion by obtaining the self-similar *** maximum luminosity is about 4.0×10^(37) erg/s(M/M_(⊙))or so(significantly less than the Eddington luminosity)due to... 详细信息

关键词： accretion solution luminosity

Transient simulation and analysis of the simultaneous load rejection process in pumped storage power stations using a 1-D-3-D coupling method

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Journal of Hydrodynamics 2021年第5期33卷 979-991页

作者： Cheng-cheng Yin Wei zeng jian-dong Yang State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China School of Civil Environmental and Mining EngineeringThe University of AdelaideAdelaideAustralia

The load rejection imposes a danger in the pumped storage hydropower plants(PSPs),especially when two or more pump turbines reject their loads *** this paper,the simultaneous load rejection scenarios in the PSPs are simulated and analyzed by using a 1-D,3-D coupling *** PSP pipe system is modeled by using the 1-D method of characteristics(MOC)and one pump turbine is modeled by using the 3-D computational fluid dynamics(CFD).The simulated flow and head are transmitted between the 1-D,3-D regions through the interfaces between these two *** assuming that the installed pump turbines are of the same type and the corresponding branch pipes have the same properties,the variations of the transient pressures and the flowrates in different pump turbines will be ***,only one pump turbine is modeled by the CFD in this study.A new branching junction boundary is proposed to assign the simulated dynamic pressures and flowrates obtained by the 3-D model to other pump *** 1-D-3-D coupling method is validated by experiments with only one pump turbine rejecting its *** simultaneous load rejection of two pump turbines is then simulated and validated by comparing the results with those of the 1-D *** building only one pump turbine 3-D model,a large amount of computational resources can be *** simultaneous load rejection scenario is then analyzed and compared with the single load rejection *** water hammer pressures and a larger rotational speed occur in the simultaneous load rejection scenario,which leads to larger pressure pulsations in the pump *** larger pressure pulsations can be further explained by the flow patterns in the runner channels,in which heavier flow separations and vortexes can be observed in the simultaneous load rejection scenario.

关键词： Pump-turbine,pumped hydro computational fluid dynamics(CFD) hydraulic transient load rejection

Improved plane layout of stabilizing piles based on the piecewise function expression of the irregular driving force

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Journal of Mountain Science 2018年第4期15卷 871-881页

作者： LIU Wen-qiang LI Qun LU jian LI Chang-dong YAO Wen-min zeng jiang-bo Faculty of Engineering China University of Geosciences CCCC Second Highway Consultants Co. Ltd. Shenzhen Geotechnical Investigation & Surveying Institute Co. Ltd.

The paper presents an improved plane layout for stabilizing piles based on a proposed piecewise function expression for the irregular driving force. Based on the specific morphological characteristics of a highway landslide, the piecewise function is used to calculate the irregular driving force by dividing the landslide into several ***, the reasonable layout range and pile spacing can be obtained based on the piecewise function expression of the irregular driving force and on relevant research results of the plane layout for stabilizing piles. Therefore, an improved plane layout of stabilizing piles is presented in consideration of a piecewise function expression of the irregular driving force. A highway landslide located in eastern Guizhou Province, China, is analyzed as a case study using the proposed method. The results demonstrate that the theory presented in this paper provides improved economic benefits and can reduce the requirednumber of stabilizing piles by 28.6% compared with the conventional plane layout scheme.

关键词： Highway landslide Driving force Piecewise function Stabilizing pile Plane layout

Formability of TRIP/TWIP Steel Containing Manganese of 18.8%

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Journal of Iron and Steel Research International 2011年第1期18卷 36-40页

作者： DING Hao DING Hua QIU Chun-lin TANG Zheng you zeng jian min YANG Ping School of Materials and Metallurgy Northeastern University Shenyang 110819 I.iaoning China State Key l.aboratory of Rolling and Automation of Northeastern University Shenyang 110819 I.iaoning China School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

The mechanical property and forming limit experiments were carried out on a higli manganese TRIP/TWIP steels with manganese of 18.8%. And the forming /imit diagram was obtained. This hig：h manganese steel shows outstanding mechanical properties comhining high strength with good formability. Its limit plane strain corresponding to the lowest point in the plain strain condition is about 38%. The effects of conventional mechanical property on the limit plane strain were analyzed. With increasing the content of Mn, the limit plane strain increases, indicating that TWlP effect is advantageous to the increase of formability. Combining with three classical models and volume invaria ble principle, a FLD model was buih, which is suitable for high manganese steels very well.

关键词： high manganese TRIP/TWIP steel mechanical property formability forming limit diagram

Automated federated learning‐based adversarial attack and defence in industrial control systems

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IET Cyber-Systems and Robotics 2024年第2期6卷 109-127页

作者： Guo-Qiang zeng Jun-min Shao Kang-Di Lu Guang-Gang Geng jian Weng College of Cyber Security Jinan UniversityGuangzhouChina National Joint Engineering Research Center of Network Security Detection and Protection Technology Jinan UniversityGuangzhouChina College of Information Science and Technology Donghua UniversityShanghaiChina

With the development of deep learning and federated learning(FL),federated intrusion detection systems(IDSs)based on deep learning have played a significant role in securing industrial control systems(ICSs).However,adversarial attacks on ICSs may compromise the ability of deep learning-based IDSs to accurately detect cyberattacks,leading to serious ***,in the process of generating adversarial samples,the selection of replacement models lacks an effective method,which may not fully expose the vulnerabilities of the *** authors first propose an automated FL-based method to generate adversarial samples in ICSs,called AFL-GAS,which uses the prin-ciple of transfer attack and fully considers the importance of replacement models during the process of adversarial sample *** the proposed AFL-GAS method,a lightweight neural architecture search method is developed to find the optimised replacement model composed of a combination of four lightweight basic ***,to enhance the adversarial robustness,the authors propose a multi-objective neural archi-tecture search-based IDS method against adversarial attacks in ICSs,called MoNAS-IDSAA,by considering both classification performance on regular samples and adver-sarial robustness *** experimental results on three widely used intrusion detection datasets in ICSs,such as secure water treatment(SWaT),Water Distribution,and Power System Attack,demonstrate that the proposed AFL-GAS method has obvious advantages in evasion rate and lightweight compared with other four ***,the proposed MoNAS-IDSAA method not only has a better classification performance,but also has obvious advantages in model adversarial robustness compared with one manually designed federated adversarial learning-based IDS method.

关键词： adversarial attacks adversarial robustness automated federated learning Industrial control system intrusion

Optimization of the O_(3)/H_(2)O_(2) process with response surface methodology for pretreatment of mother liquor of gas field wastewater

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Frontiers of Environmental Science & Engineering 2021年第4期15卷 337-349页

作者： Haoran Feng min Liu Wei zeng Ying Chen College of Architecture and Environment Sichuan UniversityChengdu610065China

The present study reports the use of the O_(3)/H_(2)O_(2) process in the pretreatment of the mother liquor of gas field wastewater(ML-GFW),obtained from the multi-effect distillation treatment of the gas field *** range of optimal operation conditions was obtained by single-factor *** surface methodology(RSM)based on the central composite design(CCD)was used for the optimization procedure.A regression model with Total organic carbon(TOC)removal efficiency as the response value was established(R^(2)=0.9865).The three key factors were arranged according to their significance as:pH>H_(2)O_(2) dosage>ozone flow *** model predicted that the best operation conditions could be obtained at a pH of 10.9,an ozone flow rate of 0.8 L/min,and H_(2)O_(2) dosage of 6.2 *** dosing ratio of ozone was calculated to be 9.84 mg O3/mg *** maximum removal efficiency predicted was 75.9%,while the measured value was 72.3%.The relative deviation was found to be in an acceptable *** ozone utilization and free radical quenching experiments showed that the addition of H_(2)O_(2) promoted the decomposition of ozone to produce hydroxyl radicals(·OH).This also improved the ozone utilization *** chromatography-mass spectrometry(GC-MS)analysis showed that most of the organic matters in ML-GFW were degraded,while some residuals needed further *** study provided the data and the necessary technical supports for further research on the treatment of ML-GFW.

关键词： High salinity High organic matters Gas field wastewater O_(3)/H_(2)O_(2) Response surface methodology

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耦合“现状—趋势”的城市地表热环境评估

灾害学 2025年第1期40卷 80-85页

作者：艾合麦提·那麦提曾坚宋苑震刘祥天津大学建筑学院天津300072

针对城市地表热环境评估较少考虑动态变化趋势的问题,该文提出了一种新的耦合“现状—趋势”的城市地表热环境评估方法。采用非参数趋势检验法分析多年地表温度的演变趋势,有效识别地表温度的升高、未变化和降低趋势,并通过与现状地表... 详细信息

针对城市地表热环境评估较少考虑动态变化趋势的问题,该文提出了一种新的耦合“现状—趋势”的城市地表热环境评估方法。采用非参数趋势检验法分析多年地表温度的演变趋势,有效识别地表温度的升高、未变化和降低趋势,并通过与现状地表温度的耦合叠加,深入挖掘现状地表温度高且呈升高趋势等热环境问题严重且紧迫的关键区域,从而实现对城市热环境状况的全面评估。以天津市中心城区为例的实证研究结果表明,该文所提出的评估方法能够有效地识别具有热环境持续恶化潜能的区域,同时也能揭示长期存在高温状况的重点区域。研究结果为城市规划与热环境精准管理提供科学评估工具,助力制定改善策略,提升热环境质量。

关键词：地表热环境评估地表温度演变趋势耦合评估天津市中心城区

Application of low-temperature thermochronology on ore deposits preservation framework in South China:a review

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Acta Geochimica 2022年第2期41卷 165-184页

作者： Kang min jian-Feng Gao State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China

South China can be divided into four metallogenic belts:The Middle-Lower Yangtze Metallogenic Belt(MLYB),Qinzhou-Hangzhou Metallogenic Belt(QHMB),Nanling Metallogenic Belt(NLMB),and Wuyi Metallogenic Belt(WYMB).The major mineralization in the four metallogenic belts is granite-related Cu–Au–Mo and porphyrite Fe-apatite,porphyry Cu(Au),and epithermal Pb–Zn–Ag,hydrothermal Cu–Au–Pb–Zn–Ag,and granite-related skarn-type and quartz-veins W–Sn,***-temperature thermochronology,including fissiontrack and U-Th/He dating,has been widely used to constrain tectonic thermal evolution and ore deposits *** fission-track annealing and He diffusion kinetics in accessory minerals,such as zircon and apatite,is essential for dating and *** this study,previous zircon fission-track(ZFT)and apatite fission-track(AFT)ages in South China were *** result shows that the ZFT ages are mainly concentrated at140–90 Ma,and the AFT ages are mainly distributed at70–40 *** age distribution and inversion temperature–time paths reveal heterogeneous exhumation histories in South *** MLYB experienced Late CretaceousCenozoic extremely slow exhumation after rapid cooling in the Early *** northern QHMB(*** southern Anhui province to the Hangzhou Bay)had a relatively faster rate of uplifting and denudation than the southern QHMB in the ***,the northern QHMB rapidly exhumed,while the continuously slow exhumation operated the southern QHMB in the *** southern NLMB had a more rapid cooling rate than the northern NLMB during the Cretaceous time,and the whole NLMB experienced rapid cooling in the Cenozoic,except that the southern Hunan province had the most rapid cooling *** WYMB possibly had experienced slow exhumation since the Late *** exhumation thickness of the four metallogenic belts since90 Ma is approximately calculated as follows:the MLYB≤3.5 km,the northern QHMB concentrated at

关键词： Low-temperature thermochronology Fissiontrack annealing and He diffusion kinetics South China Exhumation history Deposits preservation

Simulation of the erosion of casing and perforation under staged sand fracturing conditions in horizontal sections

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Journal of Hydrodynamics 2022年第4期34卷 725-743页

作者： Bao-cheng Wu Si-song Zhang jian-min Li Yu-ting Pan De-zhi zeng Hui-yong Yu Hong-jun Zhu Research Institute of Engineering Technology PetroChina Xinjiang Oilfield CompanyKaramay 834000China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China

The new fracturing technology of intensive stages and high-intensity proppant injection shows significant advantages of cost reduction and high efficiency in the volume fracturing of unconventional reservoirs,but it also intensifies the erosion of the casing and the perforations,with a perforation diameter expansion and the casing wall *** solve this problem,in view of the applications of the perforation fracturing technology under the construction conditions in Mahu Area in Xinjiang,China,the structure parameters of the downhole strings are measured and a calculation model of the perforation casing erosion is established for the large-displacement sand fracturing process in horizontal *** software ANSYS-FLUENT is used to simulate the casing and perforation erosion under different conditions of the displacement,the sand content,the proppant particle size,and the fracturing fluid viscosity in the sand fracturing *** particle size of the proppant and the viscosity of the fracturing fluid mainly affect the erosion area,but they have little influence on the erosion *** sand content and the displacement significantly affect the erosion *** these factors,the sand content has a more significant effect on the erosion rate and the displacement has a more significant effect on the erosion *** to the influence of gravity,the perforation erosion rate is larger when the phase angle ranges from 120°to 240°.

关键词： Sand fracturing erosion numerical simulation perforated casing solid-liquid flow