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The distribution and evolution of surface fractures on pan-Antarctic ice shelves

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International Journal of Digital Earth 2023年第1期16卷 3295-3320页

作者： Ao Pang Qi liang Weijia Li lei Zheng Teng Li Xiao cheng School of Geospatial Engineering and Science Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)ZhuhaiPeople’s Republic of China Key Laboratory of Comprehensive Observation of Polar Environment Sun Yat-sen UniversityMinistry of EducationZhuhaiPeople’s Republic of China

Surface fractures have a great impact on ice shelf stability in Antarctica and can be considered precursors of ice shelf ***,our understanding of the spatial distribution and temporal evolution of surface fractures on the Antarctic ice shelf is *** this study,a ResUNet model was implemented on the Moderate Resolution Imaging Spectroradiometer(MODIS)-based Mosaic of Antarctica(MOA)to identify the spatial distribution of Antarctic ice shelf surface fractures in 2004,2009,and *** accuracy of identification had an F1 value of *** model identified 44744.59±2619.61 km^(2)of surface fractures in 2004,43737.15±2644.60 km^(2)in 2009,and 42978.67±2639.33 km^(2)in *** reduction is primarily attributed to the variation in surface fractures within 20 km of the ice front,paratactically in the Amundsen and Wilkes *** shelves in the Amundsen sector typically have a widespread distribution of surface fractures,with particularly high concentrations found in the Thwaites Ice Shelf,Crosson Ice Shelf and Getz Ice *** Brunt Ice Shelf also exhibits numerous surface *** study provides comprehensive and detailed information about surface fractures on Antarctic ice shelves,carrying implications for evaluating ice shelf vulnerability.

关键词： Surface fractures Antarctic ice shelf ResUNet MOA

Collision detection of virtual plant based on bounding volume hierarchy: A case study on virtual wheat

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Journal of Integrative Agriculture 2018年第2期17卷 306-314页

作者： TANG liang SONG Wei-guo HOU Tian-cheng LIU lei-lei CAO Wei-xing ZHU Yan National Engineering and Technology Center for Information Agriculture/Key Laboratory for Crop System Analysis and Decision Making Ministry of Agriculture/Jiangsu Key Laboratory for Information Agriculture/Jiangsu Collaborative Innovation Center for Modern Crop Production/Nanjing Agricultural University

Visualization of simulated crop growth and development is of significant interest to crop research and production. This study aims to address the phenomenon of organs cross-drawing by developing a method of collision detection for improving vivid 3D visualizations of virtual wheat crops. First, the triangular data of leaves are generated with the tessellation of non-uniform rational B-splines surfaces. Second, the bounding volumes（BVs） and bounding volume hierarchies（BVHs） of leaves are constructed based on the leaf morphological characteristics and the collision detection of two leaves are performed using the Separating Axis Theorem. Third, the detecting effect of the above method is compared with the methods of traditional BVHs, Axis-Aligned Bounding Box（AABB） tree, and Oriented Bounding Box（OBB） tree. Finally, the BVs of other organs（ear, stem, and leaf sheath） in virtual wheat plant are constructed based on their geometric morphology, and the collision detections are conducted at the organ, individual and population scales. The results indicate that the collision detection method developed in this study can accurately detect collisions between organs, especially at the plant canopy level with high collision frequency. This collision detection-based virtual crop visualization method could reduce the phenomenon of organs cross-drawing effectively and enhance the reality of visualizations.

关键词： wheat collision detection bounding volume hierarchy virtual plant morphology

On PID Control Theory for Nonaffine Uncertain Stochastic Systems

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Journal of Systems Science & Complexity 2023年第1期36卷 165-186页

作者： ZHANG Jinke ZHAO cheng GUO lei Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Science University of Chinese Academy of SciencesBeijing 100049China

PID(proportional-integral-derivative)control is recognized to be the most widely and successfully employed control strategy by ***,there are limited theoretical investigations explaining the rationale why PID can work so well when dealing with nonlinear uncertain *** paper continues the previous researches towards establishing a theoretical foundation of PID control,by studying the regulation problem of PID control for nonaffine uncertain nonlinear stochastic *** be specific,a three dimensional parameter set will be constructed explicitly based on some prior knowledge on bounds of partial derivatives of both the drift and diffusion *** will be shown that the closed-loop control system will achieve exponential stability in the mean square sense under PID control,whenever the controller parameters are chosen from the constructed parameter ***,similar results can also be obtained for PD(PI)control in some special cases.A numerical example will be provided to illustrate the theoretical results.

关键词： Asymptotically regulation global stability nonaffine PID control stochastic systems uncertain structure

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Recurrent Takotsubo cardiomyopathy triggered by emotionally stressful events: A case report

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World Journal of Clinical Cases 2021年第3期9卷 677-684页

作者： Hao-Yu Wu Gong cheng lei liang Yi-Wei Cao Department of Cardiology Shaanxi Provincial People’s HospitalXi’an 710068Shaanxi ProvinceChina Department of Electrocardiology Shaanxi Provincial People’s HospitalXi’an 710068Shaanxi ProvinceChina

BACKGROUND Takotsubo cardiomyopathy(TCM)is characterized by reversible left ventricular dysfunction triggered by emotional or physical *** 1%-2%of patients with acute coronary syndrome are diagnosed with *** obstructive coronary artery disease is frequently considered to be the cause of chest pain,TCM should be considered in some clinical *** this case,clinicians did not make a timely and accurate diagnosis for TCM due to a lack of knowledge until the third hospitalization with a left *** SUMMARY A 55-year-old postmenopausal woman had intermittent chest pain following emotionally stressful events three times in the past 3 *** troponin levels increased after each instance of symptom onset.A transthoracic echocardiogram showed reversible left ventricular *** patient underwent three coronary angiograms without evidence of coronary artery disease.A left ventriculogram was first performed at the third hospitalization and revealed apical akinesia with ballooning of the apical region and consistent hypercontractile basal *** diagnosis of TCM was *** patient was treated with an angiotensin-converting-enzyme inhibitor(perindopril)and aβ-blocker(metoprolol).No complications occurred during the patient’s *** patient was told to avoid stressful *** the 9-mo follow-up visit,the patient was asymptomatic with an ejection fraction of 55%.CONCLUSION Clinicians should be conscious of the possibility of TCM,especially in postmenopausal women presenting with clinical manifestations similar to acute coronary syndrome without coronary occlusion.

关键词： Takotsubo cardiomyopathy Stress-induced cardiomyopathy Emotionally stressful event Recurrent events Chest pain Case report

Medium Optimization for Antifungal Active Substance Production from Streptomyces Lydicus Using Response Surface Methodology

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Transactions of Tianjin University 2017年第1期23卷 78-86页

作者： Yan Zhao Yingquan liang lei Liu Jingsheng cheng Yingjin Yuan Key Laboratory of Systems Bioengineering (Ministry of Education) School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China Center of Synthetic Biology Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin University Tianjin 300072 China

Response surface methodology was used to optimize the medium for antifungal active substance production from Streptomyces lydicus E12 in flask cultivation. Initially, the component factors, which influence antifungal substance production, were studied by varying one factor at a time. Starch, soybean cake powder, K2HPO4·3H2O and MgSO4·7H2O were found to have a significant effect on the production of antifungal substances by the traditional design. Then, a Box–Behnken design was applied for further optimization. A quadratic model was found to fit antifungal active substance production. The analysis revealed that the optimum values of the tested variable were starch 84.96 g/L, soybean cake powder 4.13 g/L, glucose 5 g/L, MgSO4·7H2O 1.23 g/L, K2HPO4·3H2O 2.14 g/L and NaCl 0.5 g/L. The test result of 67.44% antifungal inhibition agreed with the prediction and increased by 14.28% in comparison with the basal medium. © 2016, Tianjin University and Springer-Verlag Berlin Heidelberg.

关键词： Bacteria Enzyme inhibition Starch Surface properties

An Experimental Study on the Void Fraction for Gas-Liquid Two-Phase Flows in a Horizontal Pipe

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Fluid Dynamics & Materials Processing 2021年第6期17卷 1037-1048页

作者： Li lei Jun An Fushun liang cheng cheng Naixiang Zhou Yanhong Ning Jingzhi Zhang School of Energy and Power Engineering Shandong UniversityJinan250061China Shandong Urban and Rural Planning and Design Institute JinanChina China National Petroleum Corporation Jichai Power Co. Ltd.JinanChina Shenzhen Research Institute of Shandong University ShenzhenChina

The flow patterns and the void fraction related to a gas-liquid two-phase flow in a small channel are experimentally *** test channel is a transparent quartz glass circular channel with an inner diameter of 6.68 *** working fluids are air and water and their superficial velocities range from 0.014 to 8.127 m/s and from 0.0238 to 0.556 m/s,*** void fraction is determined using the flow pattern images captured by a high-speed camera,while quick closing valves are used for *** flow patterns are analyzed in experiments:slug flow,bubbly flow,annular flow and stratified *** intermittent flows(bubbly flow and slug flow),the cross-sectional void fraction is in a borderline condition while its probability distribution function(PDF)image displays a bimodal *** continuous flows(annular flow and stratified flow)the cross-sectional void fraction behaves as a fluctuating continuous curve while the(PDF)image displays a single peak *** volumetric void fraction data are also compared with available predictive formulas,and the results show that the agreement is very *** effort is also provided to improve the so-called Gregory and Scott model using the available data.

关键词： Gas-liquid two-phase flow small channel flow regime map probability distribution function void fraction

Effects of the extrusion parameters on microstructure,texture and room temperature mechanical properties of extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 136-146页

作者： Chenjin Zhang Guangyu Yang lei Xiao Zhiyong Kan Jing Guo Qiang Li Wanqi Jie State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China College of Materials Science and Engineering Fuzhou UniversityFuzhou 350108China College of Chemistry and Environmental Science Qujing Normal UniversityQujing 655011China

Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed *** dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)*** the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical-rare-earth(RE)*** alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening *** results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.

关键词： Mg-rare earth alloys extrusion temperature extrusion ratio extrusion speed strengthening mechanisms

Endogenous/exogenous dual stimulation“ROS engineering”amplification combined with autophagy-augmented for efficient ferroptosis therapy

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Nano Research 2025年第1期18卷 597-606页

作者： Pengye Du Pengpeng lei Yuan liang Ran An Yi Wei Shuyu Liu Jianhao Zheng Hongjie Zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China Department of Chemistry Tsinghua UniversityBeijing 100084China

“Reactive oxygen species(ROS)engineering”is one of the most promising anti-tumor treatments developed in recent *** explosion of ROS will cause oxidative stress,thereby inducing tumor cell ***,ROS accumulation in tumor cells is eliminated by endogenous cellular self-regulation *** this work,a kind of endogenous/exogenous dual stimulation nanoagent noted as UMZC is *** reaction occurs between NH_(2)-MIL-88B(Fe)contained in UMZC and the overexpression of endogenous H_(2)O_(2)to generate ROS,amplified by endogenous H_(2)S of colon tumor *** addition,NH_(2)-MIL-88B(Fe)also functions to deplete glutathione(GSH)for stopping it from consuming *** nanoparticles at the core of UMZC convert near-infrared into visible light,which excites zinc phthalocyanine to initiate the photochemical reaction that generates more ROS,thus alleviating the lack of tissue penetration depth for visible *** agonist chitosan oligosaccharides induce enhancement of cellular autophagy for disrupting cellular metabolic stress and the resistance to oxidative stress of tumor cells,allowing“ROS engineering”to fully exert anti-tumor *** of ROS generation,GSH depletion,and induced cellular autophagy caused by nanoagents have promoting effects on the occurrence of ***,the nanoagents show the ability to effectively treat colon tumors.

关键词： reactive oxygen species(ROS)engineering upconversion nanoparticles cellular autophagy ferroptosis tumor therapy

PID controller design for second order nonlinear uncertain systems

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Science China(Information Sciences) 2017年第2期60卷 5-17页

作者： cheng ZHAO lei GUO Institute of Systems Science Academy of Mathematics and Systems Science (AMSS)Chinese Academy of Sciences

Although the classical PID(proportional-integral-derivative) controller is most widely and successfully used in engineering systems which are typically nonlinear with various uncertainties, almost all the existing investigations on PID controller focus on linear systems. The aim of this paper is to present a theory on PID controller for nonlinear uncertain systems, by giving a simple and analytic design method for the PID parameters together with a mathematic proof for the global stability and asymptotic regulation of the closed-loop control systems. To be specific, we will construct a 3-dimensional manifold within which the three PID parameters can be chosen arbitrarily to globally stabilize a wide class of second order nonlinear uncertain dynamical systems, as long as some knowledge on the upper bound of the derivatives of the nonlinear uncertain function is *** will also try to make the feedback gains as small as possible by investigating the necessity of the manifold from which the PID parameters are chosen, and to establish some necessary and sufficient conditions for global stabilization of several special classes of nonlinear uncertain systems.

关键词： PID controller nonlinear uncertain systems global stability Lyapunov function asymptotic regulation