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A Multi-parameter Model for Radio Dichotomy of Active Galactic Nuclei and Jets

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Communications in Theoretical Physics 2006年第2期45卷 379-384页

作者： YE Yong-Chun WANG Ding-Xiong zuo xue-qin Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

Based on the coexistence of the Blandford-Znajek and magnetic coupling processes in black hole （BH） accretion disc, a multi-parameter model for jet powers and radio loudnees of active galactic nuclei （AGNs） is studied. It turns out that radio-loudnees of AGNs couM be governed by five parameters：（i） the BH spin, （ii） a power-law index of the variation of the magnetic field on the disc; （iii） a parameter determining the position of the inner edge of the disc, （iv） the ratio of the pressure of the magnetic field on the horizon to the ram pressure of the innermost parts of an accretion flow, and （v） the ratio of the angular velocity of the open field lines to that of the horizon. The observed dichotomy between radio-loud and radio-quiet AGNs is well interpreted by the effects of the above parameters. Furthermore, we discuss the derivative of radio loudness of AGNs with respect to each parameter separately. In addition, the effect of the screw instability on radio loudness of AGNs is discussed.

关键词： accretion accretion disc black hole physics galaxies

Controlled Remote State Preparation

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Communications in Theoretical Physics 2009年第8期52卷 235-240页

作者： WANG Zhang-Yin LIU Yi-Min zuo xue-qin ZHANG Zhan-Jun School of Physics ＆ Material Science Anhui University Hefei 230039 China Department of Physics Shaoguan University Shaoguan 512005 China

We present a scheme for remotely preparing a state via the controls of many agents in a *** thescheme,the agents' controls are achieved by utilizing quantum key ***,the original state can berestored by the receiver wi... 详细信息

关键词： controlled remote state preparation quantum key distribution single-qubit von Neumann orthogonal measurement controlled-NOT gate

Increasing operational stability of journal bearing in hydraulic suspension micro-pump by herringbone grooved structure

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Science China(Technological Sciences) 2024年第3期67卷 853-862页

作者： HONG Tao XING GuanYing zuo HuaiYu xue Song LUO XiaoBing State Key Laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The operational stability of radial journal bearings is the bottleneck that limits the reliability of hydraulic suspension micropump. Due to self-excited vibrations, the whirl amplitude of the plain journal bearing(PJB) is large at high rotational speeds,which will accelerate wear failure. It has been proven that employing herringbone grooved journal bearing(HGJB) is an effective method to reduce the whirl amplitude and improve operational stability. However, enhancing the stability of journal bearings in micro-pumps by herringbone grooved structures has rarely been studied, and its effect needs to be verified. We validated the mechanism of the stability improvement with the CFD method and compared the dynamic characteristics of HGJB and PJB by rotor dynamics evaluation and experiment. The experimental results show that under the same conditions the whirl amplitude of the HGJB decreases by 29.61% in the x direction and by 24.09% in the y direction compared with that of the PJB. This study reveals the effect of the herringbone grooved structure on the operational stability of bearings and may provide guidance for the reliability improvement of hydraulic suspension micro-pump.

关键词： journal bearing herringbone groove hydrodynamic effect micro-pump

Endoscopic ultrasound-guided biliary drainage vs percutaneous transhepatic bile duct drainage in the management of malignant obstructive jaundice

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World Journal of Gastrointestinal Surgery 2024年第6期16卷 1592-1600页

作者： qin-qin Zhu Bing-Fang Chen Yue Yang xue-Yong zuo Wen-Hui Liu Ting-Ting Wang Yin Zhang Department of Gastroenterology The Third Affiliated Hospital of Soochow University(The First People’s Hospital of Changzhou)Changzhou 213000Jiangsu ProvinceChina Department of Hepatobiliary and Pancreatic Surgery The Third Affiliated Hospital of Soochow University(The First People’s Hospital of Changzhou)Changzhou 213000Jiangsu ProvinceChina

BACKGROUND Malignant obstructive jaundice(MOJ)is a condition characterized by varying degrees of bile duct stenosis and obstruction,accompanied by the progressive development of malignant tumors,leading to high morbidity and mortality ***,the two most commonly employed methods for its management are percutaneous transhepatic bile duct drainage(PTBD)and endoscopic ultrasound-guided biliary drainage(EUS-BD).While both methods have demonstrated favorable outcomes,additional research needs to be performed to determine their relative *** compare the therapeutic effectiveness of EUS-BD and PTBD in treating *** This retrospective analysis,conducted between September 2015 and April 2023 at The Third Affiliated Hospital of Soochow University(The First People’s Hospital of Changzhou),involved 68 patients with *** patients were divided into two groups on the basis of surgical procedure received:EUS-BD subgroup(n=33)and PTBD subgroup(n=35).Variables such as general data,preoperative and postoperative indices,blood routine,liver function indices,myocardial function indices,operative success rate,clinical effectiveness,and complication rate were analyzed and compared between the *** In the EUS-BD subgroup,hospital stay duration,bile drainage volume,effective catheter time,and clinical effect-iveness rate were superior to those in the PTBD subgroup,although the differences were not statistically significant(P>0.05).The puncture time for the EUS-BD subgroup was shorter than that for the PTBD subgroup(P<0.05).Postoperative blood routine,liver function index,and myocardial function index in the EUS-BD subgroup were significantly lower than those in the PTBD subgroup(P<0.05).Additionally,the complication rate in the EUS-BD subgroup was lower than in the PTBD subgroup(P<0.05).CONCLUSION EUS-BD may reduce the number of punctures,improve liver and myocardial functions,alleviate traumatic stress,and decrease complication rates in MOJ treatment

关键词： Percutaneous hepatic biliary drainage Endoscopic ultrasound-guided biliary drainage Malignant obstructive jaundice Clinical effect Liver function Postoperative complications

Random Forest-Based Fatigue Reliability-Based Design Optimization for Aeroengine Structures

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 665-684页

作者： xue-qin Li Lu-Kai Song School of Energy and Power Engineering Beihang UniversityBeijing100191China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityKowloonHong Kong999077China Research Institute of Aero-Engine Beihang UniversityBeijing100191China

Fatigue reliability-based design optimization of aeroengine structures involves multiple repeated calculations of reliability degree and large-scale calls of implicit high-nonlinearity limit state function,leading to the traditional direct Monte Claro and surrogate methods prone to unacceptable computing efficiency and *** this case,by fusing the random subspace strategy and weight allocation technology into bagging ensemble theory,a random forest(RF)model is presented to enhance the computing efficiency of reliability degree;moreover,by embedding the RF model into multilevel optimization model,an efficient RF-assisted fatigue reliability-based design optimization framework is *** the low-cycle fatigue reliability-based design optimization of aeroengine turbine disc as a case,the effectiveness of the presented framework is *** reliabilitybased design optimization results exhibit that the proposed framework holds high computing accuracy and computing *** current efforts shed a light on the theory/method development of reliability-based design optimization of complex engineering structures.

关键词： Random forest reliability-based design optimization ensemble learning machine learning

Large eddy simulation of boundary layer combustion of hydrogen and hydrocarbon fuel films in a modeled scramjet combustor

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Chinese Journal of Aeronautics 2024年第7期37卷 109-133页

作者： Jianfei WEI Silong ZHANG Jingying zuo Xin LI Jiang qin Wen BAO School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Supersonic fuel film cooling is a promising way to simultaneously reduce the severe wall heat and friction load of the internal passage in a scramjet engine when operating at hypersonic *** eddy simulations were performed to investigate the cooling and wall friction characteristics of hydrogen and hydrocarbon films under inert and reactive *** results show that the essential difference of the turbulent state in the mixing layer contributes to the totally different behaviors of the cooling and wall friction reduction performances of the two fuel *** turbulent transport processes between the hydrogen film and the mainstream are much weaker as compared to the case of hydrocarbon film,making inert hydrogen rather superior in cooling and friction reduction ***,the increase of wall temperature for hydrogen film under the inert case is mainly driven by the loss of hydrogen with high heat capacity instead of by direct heat ***,the film cooling performance severely deteriorates when the hydrogen film burns due to presence of severe heat release sources near the *** the other hand,combustion of hydrocarbon film in the boundary layer can remarkably improve its originally barely-satisfactory cooling and friction reduction performance to the level comparable to that of hydrogen film,due to the suppression of turbulent transport processes in the mixing layer and presence of heat absorption sources near the ***,the hydrogen film is more advantageous in friction reduction,while the hydrocarbon film is more suitable for cooling.

关键词： Supersonic film cooling Hydrogen Hydrocarbon Boundary layer combustion Large eddy simulation

Critical environmental factors affecting mountain geohazards in a warming climate in Southwest China

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Advances in Climate Change Research 2024年第4期15卷 695-707页

作者： Xiao-Ming XU Peng CUI xue-qin ZHANG Key Lab of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 10010lChina University of Chinese Academy of Sciences Beijing 100049China China-Pakistan Joint Research Center on Earth Sciences Chinese Academy of Sciences and Higher Education CommissionIslamabad 45320Pakistan

Environmental factors are essential input variables for susceptibility assessment models of mountain ***,the existing literature provides a limited understanding of the relative contribution of these factors to the occurrence of geohazards with a warming climate,posing tremendous challenges for risk management in mountainous ***'an city is susceptible to hazards because of its steep terrain,abundant precipitation and active seismic *** this regard,we utilise the GeoDetector model to extract critical environmental factors affecting the spatial patterns of mountain geohazards(i.e.,landslide,debris flow and rockfall)in Southwest *** analysis indicates that the factors with the highest explanatory power for the spatial distribution of landslides,debris flows,and rockfalls are soil property,extreme precipitation and extreme temperature,***,we revealed the synergistic effects among factors given their larger q-value than individual *** further explored the responses of mountain geohazards to climate change,including the rising temperature and precipitation,because the frequent occurrence of mountain geohazards is closely related to a warming *** variation in snow water equivalent caused by antecedent snowfall and snowdrifts acts as a crucial indicator for geohazards,highlighting the significance of snow and wind observations in meteorological nowcasting and disaster *** disclose the phenomenon of the geohazard hysteresis to the precipitation peak resulting from the top-down(i.e.,precipitation-runoff and surface-deep soil moisture)peak *** work is expected to enhance the precision of susceptibility assessment models and the reliability of short-term forecasts for mountain geohazards.

关键词： Mountain geohazards Environmental factors Climate change GeoDetector Southwest China

A Novel Analysis Approach of Uniform Persistence for an Epidemic Model with Quarantine and Standard Incidence Rate

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 695-707页

作者： Song-bai GUO Yu-ling xue Xi-liang LI zuo-huan ZHENG School of Science Beijing University of Civil Engineering and ArchitectureBeijing 102616China School of Mathematics and Statistics Hainan Normal UniversityHaikou 571158China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China School of Mathematics and Information Science Shandong Technology and Business UniversityYantai 264005China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

Inspired by the transmission characteristics of the coronavirus disease 2019(COVID-19),an epidemic model with quarantine and standard incidence rate is first developed,then a novel analysis approach is proposed for finding the ultimate lower bound of the number of infected individuals,which means that the epidemic is uniformly persistent if the control reproduction number R_(c)>*** approach can be applied to the related biomat hem at ical models,and some existing works can be improved by using *** addition,the infection-free equilibrium V^(0)of the model is locally asymptotically stable(LAS)if R_(c)1.

关键词： uniform persistence epidemic model control reproduction number quarantine standard incidence rate

Intensified warming suppressed the snowmelt in the Tibetan Plateau

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Advances in Climate Change Research 2024年第3期15卷 452-463页

作者： Xiang LI Peng CUI xue-qin ZHANG Fang ZHANG Key Lab of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China China‒Pakistan Joint Research Center on Earth Sciences Chinese Academy of Sciences and Higher Education CommissionIslamabad 45320Pakistan

Understanding how hydrological factors interrelate is crucial when examining the impact of climate warming on ***,these connections are often overlooked,leading to an unclear relationship between temperature and *** study investigates the complex interplay between temperature and snowmelt in the Tibetan Plateau from 1961 to 2020,focusing on how extreme high-temperature events affect the frequency of extreme *** a structural equation model,we detected three temperature-related factors that predominantly influenced snowmelt and extreme *** annual average temperature was found to have a significant indirect impact on snowmelt,mediated by changes in snowfall,snow depth and snow *** contrast,high-temperature days(daily maximum temperatures exceeding the 90th percentile)and heat waves(at least three consecutive high-temperature days)negatively affected extreme snowmelt directly or *** direct effect of increasing extreme temperature events was associated with an earlier onset of high-temperature periods,which accelerated snowmelt and shortened the duration of extreme snowmelt ***,the reduction in snow cover owing to warming emerged as a main factor suppressing snowmelt and extreme snowmelt *** also revealed spatiotemporal variations in the temperature‒snowmelt relationship that highly depended on changes in snowmelt *** study elucidated why warming suppresses snowmelt and extreme snowmelt events in the Tibetan Plateau,highlighting the mediating roles of snow-related and phenological *** findings will provide scientific support for climate simulation and water management policymaking in alpine regions worldwide.

关键词： Climate change Extreme temperature Snowmelt Structural equation model Tibetan Plateau