检索结果-南通市图书馆

维普期刊数据库

Downregulation of cold-inducible RNA-binding protein activates mitogen-activated protein kinases and impairs spermatoRenic function in mouse testes

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2012年第6期14卷 884-889页

作者： Zhi-Ping Xia Xin-Min Zheng Hang Zheng Xiao-Jun liu gui-yong liu Xing-Huan Wang Department of Urology Zhongnan Hospital of Wuhan University Wuhan 430071 China Department of Urology Qianjiang Central Hospital Qianjiang 433100 China

Cold-inducible RNA-binding protein （CIRP） is an RNA-binding protein that is expressed in normal testes and downregulated after heat stress caused by cryptorchidism, varicocele or environmental temperatures. The purpose of this study was to investigate the functions of CIRP in the testes. We employed RNAi technique to knock down the expression of CIRP in the testes, and performed haematoxylin and eosin staining to evaluate morphological changes following knockdown. Germ cell apoptosis was examined by terminal deoxynucleotidal transferase-mediated dUTP nick end labelling （TUNEL） assay, and mitogen-activated protein kinase （MAPK） signalling pathways were investigated by Western blotting to determine the possible mechanism of apoptosis. We found that using siRNA is a feasible and reliable method for knocking down gene expression in the testes. Compared to controls, the mean seminiferous tubule diameter （MSTD） and the thickness of the germ cell layers decreased following siRNA treatment, whereas the percentage of apoptotic seminiferous tubules increased. The p44/p42, p38 and SAPK/JNK MAPK pathways were activated after downregulation of CIRP. In conclusion, we discovered that downregulation of CIRP resulted in increased germ cell apoptosis, possibly viathe activation of the p44/p42, p38 and SAPK/JNK MAPK pathways.

关键词： cold-inducible RNA-binding protein (CIRP) mitogen-activated protein kinase (MAPK) siRNA in vivo spermatogenesis heat stress male infertility

Groundwater Flow Driven by Heat

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Groundwater Science and Engineering 2013年第3期1卷 22-27页

作者： Zong-jun Gao yong-gui liu Shandong University of Science and Technology The Second Hydro-Engineering Geology Brigade Shanxi Geologic Bureau

The temperature of groundwater will be increasing gradually while it is recharged and infiltrated down to the depth because of the geothermal gradient. So the density of water is smaller and smaller. The author puts forward the heat-driving mechanism that the movement of the groundwater is caused by the density differences from different temperatures. Based on this idea, the author proposes the short range recharge model of geothermal water in flat terrain hilly area. The model explains the coexistence mechanism of recharge and discharge(hot springs) zones can be at the same altitude. Considering that the temperature is an important driving force of groundwater movement, the paper puts forward and demonstrates that the hot springs can expose at higher lands while the recharge zone being situated lower lying areas.

关键词： Groundwater flow Heat Temperature difference Density difference Driving mechanism

The Average Widths and Non-linear Widths of the Classes of Multivariate Functions with Bounded Moduli of Smoothness

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2002年第4期18卷 663-674页

作者： yong-ping liu, gui-qiao XuDepartment of Mathematics, Beijing Normal University, Beijing 100875, China Department of Mathematics, Tianjin Normal Univesity, Tianjin 300074. China Department of Mathematics Beijing Normal University Beijing 100875 China Department of Mathematics Tianjin Normal Univesity Tianjin 300074 China

The classes of the multivariate functions with bounded moduli on Rd and Td are given and their average σ-widths and non-linear n-widths are discussed. The weak asymptotic behaviors are established for the correspondi... 详细信息

关键词： Multivariate function classes average width non-linear width

维普期刊数据库

An asymmetrically variable wingtip anhedral angles morphing aircraft based on incremental sliding mode control:Improving lateral maneuver capability

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2025年第1期38卷 455-470页

作者： Xiaodong liu yong XU Jianqiao LUO School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Chongqing Innovation Center Beijing Institute of TechnologyChongqing 401120China

This paper presents the design of an asymmetrically variable wingtip anhedral angles morphing aircraft,inspired by biomimetic mechanisms,to enhance lateral maneuver ***,we establish a lateral dynamic model considering additional forces and moments resulting during the morphing process,and convert it into a Multiple Input Multiple Output(MIMO)virtual control system by importing virtual ***,a classical dynamics inversion controller is designed for the outer-loop system.A new Global Fast Terminal Incremental Sliding Mode Controller(NDO-GFTISMC)is proposed for the inner-loop system,in which an adaptive law is implemented to weaken control surface chattering,and a Nonlinear Disturbance Observer(NDO)is integrated to compensate for unknown *** whole control system is proven semiglobally uniformly ultimately bounded based on the multi-Lyapunov function ***,we consider tracking errors and self-characteristics of actuators,a quadratic programmingbased dynamic control allocation law is designed,which allocates virtual control inputs to the asymmetrically deformed wingtip and *** dynamic models are incorporated to ensure physical realizability of designed allocation ***,comparative experimental results validate the effectiveness of the designed control system and control allocation *** NDO-GFTISMC features faster convergence,stronger robustness,and 81.25%and 75.0%reduction in maximum state tracking error under uncertainty compared to the Incremental Nonlinear Dynamic Inversion Controller based on NDO(NDO-INDI)and Incremental Sliding Mode Controller based on NDO(NDO-ISMC),*** design of the morphing aircraft significantly enhances lateral maneuver capability,maintaining a substantial control margin during lateral maneuvering,reducing the burden of the rudder surface,and effectively solving the actuator saturation problem of traditional aircraft during lateral maneuvering.

关键词： Morphing aircraft Lateral maneuver capability Incremental sliding mode control Multi-Lyapunov function method Control theory Control allocation law

Offload Strategy for Edge Computing in Satellite Networks Based on Software Defined Network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2025年第1期82卷 863-879页

作者： Zhiguo liu Yuqing gui Lin Wang Yingru Jiang Communication and Network Laboratory Dalian UniversityDalian116622China College of Environment and Chemical Engineering Dalian UniversityDalian116622China

Satellite edge computing has garnered significant attention from researchers;however,processing a large volume of tasks within multi-node satellite networks still poses considerable *** sharp increase in user demand for latency-sensitive tasks has inevitably led to offloading bottlenecks and insufficient computational capacity on individual satellite edge servers,making it necessary to implement effective task offloading scheduling to enhance user *** this paper,we propose a priority-based task scheduling strategy based on a Software-Defined Network(SDN)framework for satellite-terrestrial integrated networks,which clarifies the execution order of tasks based on their ***,we apply a Dueling-Double Deep Q-Network(DDQN)algorithm enhanced with prioritized experience replay to derive a computation offloading strategy,improving the experience replay mechanism within the Dueling-DDQN ***,we utilize the Deep Deterministic Policy Gradient(DDPG)algorithm to determine the optimal resource allocation strategy to reduce the processing latency of *** results demonstrate that the proposed d3-DDPG algorithm outperforms other approaches,effectively reducing task processing latency and thus improving user experience and system efficiency.

关键词： Satellite network edge computing task scheduling computing offloading

Analysis of vibration response characteristics of subway station and superstructure with hard combination

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2025年第1期24卷 271-281页

作者： Jia Jinglong Xu Weiping liu Xu Wei yong Key Laboratory of Transportation Tunnel Engineering Ministry of EducationSchool of Civil EngineeringSouthwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Intelligent Geotechnics and Tunnelling Chengdu 610031China China Railway Eryuan Chongqing Survey and Design Institute Co.Ltd. Chongqing 400023China

The vibration response and noise caused by subway trains can affect the safety and comfort of *** study the dynamic response characteristics of subway stations and superstructures under train loads with a hard combination,a numerical model is developed in this *** indoor model test verified the accuracy of the numerical *** influence laws of different hard combinations,train operating speeds and modes were studied and evaluated *** results show that the frequency corresponding to the peak vibration acceleration level of each floor of the superstructure property is concentrated at 10–20 *** vibration response decreases in the high-frequency parts and increases in the lowfrequency parts with increasing distance from the ***,the factors,such as train operating speed,operating mode,and hard combination type,will affect the vibration of the *** vibration response under the reversible operation of the train is greater than that of the unidirectional *** operating speed of the train is proportional to its vibration *** vibration amplification area appears between the middle and the top of the superstructure at a higher train *** vibration acceleration level will exceed the limit value of relevant regulations,and vibration-damping measures are *** the scope of application,this study provides some suggestions for constructing subway stations and superstructures.

关键词： subway station superstructure vibration response hard combination

维普期刊数据库

Chattering-Free Fault-Tolerant Cluster Control and Fault Direction Identification for HIL UAV Swarm With Pre-Specified Performance

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2025年第1期12卷 183-197页

作者： Pei-Ming liu Xiang-gui Guo Jian-Liang Wang Daniel Coutinho Lihua Xie the Beijing Engineering Research Center of Industrial Spectrum Imaging School of Automation and Electrical Engineering University of Science and Technology Beijing the Shunde Graduate School of University of Science and Technology Beijing IEEE Autonomous Intelligent Systems Department Hangzhou Innovation Institute of Beihang University the Department of Automation and Systems Universidade Federal de Santa Catarina the School of Electrical and Electronic Engineering Nanyang Technological University

In this paper, the problem of pre-specified performance fault-tolerant cluster consensus control and fault direction identification is solved for the human-in-the-loop(HIL) swarm unmanned aerial vehicles(UAVs) in the presence of possible nonidentical and unknown direction faults(NUDFs) in the yaw *** control strategy begins with the design of a pre-specified performance event-triggered observer for each individual *** observers estimate the outputs of the human controlled UAVs, and simultaneously achieve the distributed design of actual control signals as well as cluster consensus of the observer *** is worth mentioning that these observers require neither the high-order derivatives of the human controlled UAVs' output nor a priori knowledge of the initial conditions. The fault-tolerant controller realizes the pre-specified performance output regulation through error transformation and the Nussbaum function. It should be pointed out that there are no chattering caused by the jump of the Nussbaum function when a reverse fault occurs. In addition, to provide a basis for further solving the problem of physical malfunctions, a fault direction identification algorithm is proposed to accurately identify whether a reverse fault has occurred. Simulation results verify the effectiveness of the proposed control and fault direction identification strategies when the reverse faults occur.

关键词： Chattering-free cluster consensus fault direction identification human-in-the-loop (HIL) nonidentical and unknown direction faults (NUDFs) pre-specified performance swarm unmanned aerial vehicles (UAVs)

Upcycling of polyphenylene oxide into 2,6-dimethyl aniline via depolymerization and amination over a Pt/CeO_(2) catalyst

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第2期68卷 520-525页

作者： Shengchao Jia Wenke Zhao Xiaohui liu yong Guo Yanqin Wang State Key Laboratory of Green Chemical Engineering and Industrial Catalysis Research Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China Shanghai Key Laboratory of Functional Materials Chemistry School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Upcycling of plastic waste into N-containing compound is a novel and attractive strategy for its disposal and will opens up a promising direction for the production of value-added ***,an efficient strategy for the depolymerization-amination of polyphenylene oxide(PPO)into 2,6-dimethyl aniline is developed over a simple Pt/CeO_(2) *** C–O linkages of PPO can be selectively broken,producing 2,6-dimethyl phenol and then hydrogenated and aminated to 2,6-dimethyl cyclohexylamine over the Pt/CeO_(2) ***,2,6-dimethyl aniline was produced with high selectivity through the dehydrogenation of 2,6-dimethyl cyclohexylamine in the same *** can be used as the hydrogen-acceptor in the dehydrogenation step and enhance the selectivity of target *** N-containing compound,2,6-dimethyl aniline,is obtained and separated after HCl ***,the Pt/CeO_(2) catalyst exhibit remarkable stability and can sustainably catalyze the synthesis of 2,6-dimethyl aniline in several cycles.

关键词： PPO depolymerization-amination 2,6-dimethyl aniline Pt/CeO_(2)

Leaching of WO_(3)from sulfuric acid converted product of scheelite in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2025年第1期35卷 326-337页

作者： Lei-ting SHEN Yu liu Juan-lang GUO Qiu-sheng ZHOU Tian-gui QI Zhi-hong PENG gui-hua liu Xiao-bin LI School of Metallurgy and Environment Central South UniversityChangsha 410083China

The leaching of sulfuric acid converted product of scheelite in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution was systemically studied to improve sulfuric acid conversion−ammonium salts leaching technology route for ammonium paratungstate *** results showed that the WO_(3)leaching efficiency was about 99%under optimal conditions of 350 r/min,liquid-to-solid ratio of 3 mL/g,1 mol/L NH_(4)HCO_(3),4 mol/L NH_(3)·H_(2)O,25℃,and 15 *** the leaching,CaSO_(4)almost had no change and was still in a banding or rod-like shape in short leaching time,while conglobate CaCO_(3)was gradually formed on the CaSO_(4)surface.A secondary reaction might occur between CaSO_(4)and WO_(4)^(2−),which could be restrained by a certain amount of CO_(3)^(2−)in the *** was no CaCO_(3)phase determined by XRD in leaching residue of converted product for scheelite concentrate under optimal conditions,which was different from that for synthetic *** leaching process could be explained by neutralization reaction of H_(2)WO_(4)and solid transformation of CaSO_(4)in NH_(3)·H_(2)O−NH_(4)HCO_(3)solution.

关键词： tungstic acid calcium sulfate leaching mechanism calcium carbonate ammonium tungstate