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Fixed-Time Gradient Flows for Solving Constrained Optimization:A Unified Approach

IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1849-1864页

作者： Xinli shi Xiangping xu Guanghui wen Jinde Cao IEEE the School of Cyber Science and Engineering Southeast University the School of Mathematics Southeast University

The accelerated method in solving optimization problems has always been an absorbing topic. Based on the fixedtime(FxT) stability of nonlinear dynamical systems, we provide a unified approach for designing FxT gradient flows(FxTGFs).First, a general class of nonlinear functions in designing FxTGFs is provided. A unified method for designing first-order FxTGFs is shown under Polyak-?jasiewicz inequality assumption, a weaker condition than strong convexity. When there exist both bounded and vanishing disturbances in the gradient flow, a specific class of nonsmooth robust FxTGFs with disturbance rejection is presented. Under the strict convexity assumption, Newton-based FxTGFs is given and further extended to solve time-varying optimization. Besides, the proposed FxTGFs are further used for solving equation-constrained optimization. Moreover, an FxT proximal gradient flow with a wide range of parameters is provided for solving nonsmooth composite optimization. To show the effectiveness of various FxTGFs, the static regret analyses for several typical FxTGFs are also provided in detail. Finally, the proposed FxTGFs are applied to solve two network problems, i.e., the network consensus problem and solving a system linear equations, respectively, from the perspective of optimization. Particularly, by choosing component-wisely sign-preserving functions,these problems can be solved in a distributed way, which extends the existing results. The accelerated convergence and robustness of the proposed FxTGFs are validated in several numerical examples stemming from practical applications.

关键词： Robustness Stability analysis Nonlinear dynamical systems Distributed algorithms Optimization Numerical stability Convergence

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Non-Gaussian feature of the output field from a double qubit-cavity ultrastrong coupling system

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Communications in Theoretical Physics 2024年第07期76卷 32-38页

作者： Sheng-wen xu shi-yu Dai Teng Zhao Center for Quantum Science and Technology Jiangxi Normal University

We investigate the non-Gaussian feature of radiation in a circuit quantum electrodynamics(QED) system where two qubits are strongly coupled to a single-mode cavity. In the regime of ultrastrong coupling(USC), the rotating-wave approximation is not valid, and the Rabi Hamiltonian contains counter-rotating wave terms, leading to level crossing and avoided crossings in the energy spectrum. We further analyze the intensity-amplitude correlation of the output field in these two novel scenarios. In the USC regime, the creation and annihilation operators in the correlation function are replaced, allowing for the identification of non-Gaussian features in the output field. Our findings reveal that despite the absence of squeezing effects in the output light, significant non-Gaussian characteristics are present. Additionally, we demonstrate that as the driving or coupling strength increases, the non-Gaussian features of the output field become more pronounced. This suggests that USC systems hold broad potential applications in the realms of nonlinear optics and the generation of non-Gaussian states.

关键词： intensity-amplitude correlation non-Gaussian ultrastrong coupling

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Catalytic effect in lithium metal batteries: From heterogeneous catalyst to homogenous catalyst

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Journal of Energy Chemistry 2024年第3期90卷 305-326,I0008页

作者： Haining Fan xuan-wen Gao Hailong xu Yichun Ding shi-xue Dou wen-Bin Luo School of Fashion and Textiles The Hong Kong Polytechnic UniversityHong Kong 100872China Institute for Energy Electrochemistry and Urban Mines Metallurgy School of MetallurgyNortheastern UniversityShenyang 110819LiaoningChina Institute of Energy Materials Science University of Shanghai for Science and TechnologyShanghai 200000China State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710000ShaanxiChina

Lithium metal batteries are regarded as prominent contenders to address the pressing needs owing to the high theoretical *** the broader implementation,the primary obstacle lies in the intricate multi-electron,multi-step redox reaction associated with sluggish conversion kinetics,subsequently giving rise to a cascade of parasitic *** order to smooth reaction kinetics,catalysts are widely introduced to accelerate reaction rate via modulating the energy *** past decades,a large amount of research has been devoted to the catalyst design and catalytic mechanism exploration,and thus the great progress in electrochemical performance has been ***,it is necessary to make a comprehensive review toward key progress in catalyst design and future development *** this review,the basic mechanism of lithium metal batteries is provided along with corresponding advantages and existing challenges detailly *** main catalysts employed to accelerate cathode reaction with emphasis on their catalytic mechanism are summarized as ***,the rational design and innovative direction toward efficient catalysts are suggested for future application in metal-sulfur/gas battery and *** review is expected to drive and benefit future research on rational catalyst design with multi-parameter synergistic impacts on the activity and stability of next-generation metal battery,thus opening new avenue for sustainable solution to climate change,energy and environmental issues,and the potential industrial economy.

关键词： Energy storage and conversion Metal battery Sulfur battery Air battery Catalytic effect Heterogeneous catalyst Homogeneous catalyst

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Utility of real-time 3D visualization system in the early stage of phacoemulsification training

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International Journal of Ophthalmology(English edition) 2024年第3期17卷 577-582页

作者： Zhe xu Dan Chen Jing-Wei xu Yi-xuan Feng Ce shi Li Zhang wen xu Eye Center the Second Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhou 310009Zhejiang ProvinceChina Zhejiang Provincial Key Laboratory of Ophthalmology Hangzhou 310009Zhejiang ProvinceChina Zhejiang Provincial Clinical Research Center for Eye Diseases Hangzhou 310009Zhejiang ProvinceChina Zhejiang Provincial Engineering Institute on Eye Diseases Hangzhou 310009Zhejiang ProvinceChina

●AIM:To determine the teaching effects of a real-time three dimensional(3D)visualization system in the operating room for early-stage phacoemulsification training.●METHODS:A total of 10 ophthalmology residents of the first-year postgraduate were *** the residents were novices to cataract ***-time cataract surgical observations were performed using a custom-built 3D visualization *** training lasted 4wk(32h)in all.A modified International Council of Ophthalmology’s Ophthalmology Surgical Competency Assessment Rubric(ICO-OSCAR)containing 4 specific steps of cataract surgery was *** self-assessment(self)and expert-assessment(expert)were performed through the microsurgical attempts in the wet lab for each participant.●RESULTS:Compared with pre-training assessments(self 3.2±0.8,expert 2.5±0.6),the overall mean scores of posttraining(self 5.2±0.4,expert 4.7±0.6)were significantly improved after real-time observation training of 3D visualization system(P<0.05).Scores of 4 surgical items were significantly improved both self and expert assessment after training(P<0.05).●CONCLUSION:The 3D observation training provides novice ophthalmic residents with a better understanding of intraocular microsurgical *** is a useful tool to improve teaching efficiency of surgical education.

关键词： 3D visualization system phacoemulsification training wet lab

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Polyimide covalent organic frameworks as efficient solid-state Li^(+) electrolytes

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Science China Chemistry 2024年第5期67卷 1647-1652页

作者： xu Liu shi Wang Siqi Liu Chengfang Liu Xiangchun Li Jian Wu Dazhi Li shihao xu Chongyang Liu wen-Yong Lai State Key Laboratory of Organic Electronics and Information Displays(SKLOEID) Institute of Advanced Materials(IAM)School of Chemistry and Life SciencesNanjing University of Posts&TelecommunicationsNanjing 210023China

Covalent organic frameworks(COFs) are attractive porous crystalline materials with extremely high stability, easy functionalization, and open channels, which are expected to be unique ion conductors/transporters in lithium ion batteries(LIBs). Despite recent advances, low ion conductivity and low transference number, resulting in low charging/discharging rate, low energy density, and short battery life, are the main issues that limit their direct application as solid electrolytes in LIBs. Here, we designed and synthesized a novel polyimide COF, namely, TAPA-PDI-COF, with abundant C=O groups, which has been successfully employed as high-performance solid electrolytes by doping TAPA-PDI-COF and succinonitrile(SN). Both the well-defined nanochannels of COFs and SN confined in the well-aligned channels restricted the free migration of anions, while C=O on COFs and CN groups of SN enhanced Li^(+) transport, thus achieving a high ion conductivity of 0.102 m S cm^(-1)at 80 °C and a high lithium-ion transference number of 0.855 at room temperature. According to density functional theory(DFT)calculations, Li-ion migration mainly adopted in-plane transport rather than the axial pathway, which may be due to the shorter hopping distances in the planar pathway. The results suggest an effective strategy for the design and development of all-solidstate ionic conductors for achieving high-performance LIBs.

关键词： lithium ion batteries(LIBs) covalent organic frameworks(COFs) solid-state ion conductors solid-state electrolytes ion conductivity

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Comparative analysis of the short and medium-term efficacy of the Da Vinci robot versus laparoscopic total mesangectomy for rectal cancer

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World Journal of Gastrointestinal Surgery 2024年第6期16卷 1681-1690页

作者： Wei-Ge Gao wen shi xu-Chen Gong Zhi-wen Li Yiminjiang Tuoheti Department of Anorectal Surgery People’s Hospital of Xinjiang Uygur Autonomous RegionUrumqi 830001Xinjiang Uygur Autonomous RegionChina Department of Anus and Intestine Surgery Cancer Hospital of Chinese Academy of Medical SciencesBeijing 100084China

BACKGROUND The Da Vinci robot-assisted surgery technique has been widely used in laparo-scopic mesangectomy for rectal ***,the short-term efficacy of these procedures compared to traditional laparoscopic surgery remains *** purpose of this study was to compare and analyze the short-and medium-term efficacy of Da Vinci robot and laparoscopic surgery in total mesangectomy(TME)for rectal cancer,so as to provide guidance and reference for clinical *** To investigate the safety and long-term efficacy of robotic and laparoscopic total mesorectal resection for the treatment of rectal *** The clinicopathologic data of 240 patients who underwent TME for rectal cancer in the Anorectal Department of People’s Hospital of Xinjiang Uygur Autonomous Region from August 2018 to March 2023 were retrospectively *** them,112 patients underwent laparoscopic TME(L-TME)group,and 128 patients underwent robotic TME(R-TME)*** intraoperative,postoperative,and follow-up conditions of the two groups were *** The conversion rate of the L-TME group was greater than that of the R-TME group(5.4%vs 0.8%,χ^(2)=4.417,P=0.036).The complication rate of the L-TME group was greater than that of the R-TME group(32.1%vs 17.2%,χ^(2)=7.290,P=0.007).The percentage of positive annular margins in the L-TME group was greater than that in the R-TME group(7.1%vs 1.6%,χ^(2)=4.658,P=0.031).The 3-year disease-free survival(DFS)rate and overall survival(OS)rate of the L-TME group were lower than those of the R-TME group(74.1%vs 85.2%,χ^(2)=4.962,P=0.026;81.3%vs 91.4%,χ^(2)=5.494,P=0.019);in patients with American Joint Committee on Cancer stage III DFS rate and OS rate in the L-TME group were significantly lower than those in the R-TME group(52.5%vs 76.1%,χ^(2)=5.799,P=0.016;65.0%vs 84.8%,χ^(2)=4.787,P=0.029).CONCLUSION Compared with the L-TME group,the R-TME group had a better tumor prognosis and was more favorable for patients with rectal canc

关键词： Rectal tumor Robots Laparoscopy Total mesangectomy Survival prognosis Retrospective analysis

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Design and performance evaluation of a large field-of-view dual-particle time-encoded imager based on a depth-of-interaction detector

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Nuclear Science and Techniques 2024年第4期35卷 1-14页

作者： Dong Zhao xu-wen Liang Ping-Kun Cai Wei Cheng wen-Bao Jia Da-Qian Hei Qing Shan Yong-Sheng Ling Chao shi Department of Nuclear Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 211106China Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions Suzhou 215000China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China

Time-encoded imaging is useful for identifying potential special nuclear materials and other radioactive sources at a *** this study,a large field-of-view time-encoded imager was developed for gamma-ray and neutron source hotspot imaging based on a depth-of-interaction(DOI)*** imager primarily consists of a DOI detector system and a rotary dual-layer cylindrical coded *** EJ276 plastic scintillator coupled with two SiPMs was designed as the DOI detector to increase the field of view and improve the imager *** difference in signal time at both ends and the log of the signal amplitude ratio were used to calculate the interaction position *** position resolution of the DOI detector was calibrated using a collimated Cs-137 source,and the full width at half maximum of the reconstruction position of the Gaussian fitting curve was approximately 4.4 *** DOI detector can be arbitrarily divided into several units to independently reconstruct the source distribution *** unit length was optimized via Am-Be source-location experiments.A multidetector filtering method is proposed for image *** method can effectively reduce image noise caused by poor DOI detector position *** vertical field of view of the imager was(-55°,55°)when the detector was placed in the center of the coded mask.A DT neutron source at 20 m standoff could be located within 2400 s with an angular resolution of 3.5°.

关键词： Time-encoded imager Depth-of-interaction detector Dual-particle imaging Hotspot imaging

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Unconditionally stable Crank-Nicolson algorithm with enhanced absorption for rotationally symmetric multi-scale problems in anisotropic magnetized plasma

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Journal of Systems Engineering and Electronics 2024年第1期35卷 65-73页

作者： wen Yi WANG Junxiang xu Hongbing School of Automatic Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Beijing Institute of Aerospace Systems Engineering Beijing 100076China

Large calculation error can be formed by directly employing the conventional Yee’s grid to curve *** order to alleviate such condition,unconditionally stable CrankNicolson Douglas-Gunn(CNDG)algorithm with is proposed for rotationally symmetric multi-scale problems in anisotropic magnetized *** the CNDG algorithm,an alternative scheme for the simulation of anisotropic plasma is proposed in body-of-revolution *** perfectly matched layer(CPML)formulation is proposed to efficiently solve the open region *** example is carried out for the illustration of effectiveness including the efficiency,resources,and *** the results,it can be concluded that the proposed scheme shows considerable performance during the simulation.

关键词： anisotropic magnetized plasma body-of-revolution(BOR) Crank-Nicolson Douglas-Gunn(CNDG) finite-difference time-domain(FDTD) perfectly matched layer(PML) rotationally symmetric multi-scale problems

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Giant bile duct dilatation in newborn:A case report

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World Journal of Clinical Cases 2024年第6期12卷 1150-1156页

作者： Dong-wen Quan Peng-Gang Li Xiang-Hua xu shi-Qi Liu The Second Clinical Medical School Shaanxi University of Chinese MedicineXianyang 712000Shaanxi ProvinceChina The First School of Clinical Medicine Shaanxi University of Chinese MedicineXianyang 712000Shaanxi ProvinceChina Department of Hepatobiliary Surgery The First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061Shaanxi ProvinceChina Department of Neonatal Surgery Xi’an Children’s Hospital Affiliated Xi’an Jiaotong UniversityXi’an 710003Shaanxi ProvinceChina

BACKGROUND Giant congenital biliary dilation(CBD)is a rare condition observed in clinical *** born with this condition often experience a poor overall health status,and the disease progresses rapidly,leading to severe biliary obstruction,infections,pressure exerted by the enlarged CBD on abdominal organs,disturbances in the internal environment,and multiple organ *** treatment of giant CBD using laparoscopy is challenging due to the high degree of variation in the shape of the bile duct and other organs,making it difficult to separate the bile duct wall from adjacent tissues or to control *** SUMMARY Herein,we present the details of an 11-d-old male newborn who was diagnosed with giant *** patient was admitted to the neonatal surgery department of our hospital due to a history of common bile duct cyst that was detected more than 3 mo ago,and also because the patient had been experiencing yellowish skin for the past 9 *** abnormal echo in the fetal abdomen was first noticed by the patient’s mother during a routine ultrasound examination at a local hospital,when the patient was at 24 wk+6 d of *** finding raised concerns about the possibility of congenital biliary dilatation(22 mm×21 mm).Subsequent ultrasound examinations at different hospitals consistently confirmed the presence of a congenital biliary *** specific treatment was administered for biliary dilatation during this period.A computed tomography scan conducted during the hospitalization revealed a large cystic mass in the right upper quadrant and pelvis,measuring approximately 9.2 cm×7.4 cm×11.3 *** on the CONCLUSION The analysis reveals that prenatal imaging techniques,such as ultrasound and magnetic resonance imaging,play a crucial role in the early diagnosis,fetal prognosis,and treatment plan for giant *** surgery for giant CBD presents certain challenges,including difficulties in separating the cyst wall,anastomosis,and hemos

关键词： Acute cholangitis Congenital biliary dilation Laparoscopic surgery vs Open hepatic duct-jejunostomy Case report

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A low-power Bluetooth-based wireless sensor network and its global confliction-solving impact localization method

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Chinese Journal of Aeronautics 2024年第1期37卷 153-161页

作者： Yuanjia WANG Lei QIU Qiyun xu Liming shi College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Electrical and Electronic Engineering University of EdinburghEdinburgh EH89YLUK

During the whole service lifetime of aircraft structures with composite materials,impacts are inevitable and can usually cause severe but barely visible *** the occurrences of impact are random and unpredictable,it is a hotspot direction to develop an online impact monitoring system that can meet strict limitations of aerospace applications including small size,light weight,and low power ***(PZT)sensor,being able to generate impact response signals with no external power and cover a large-scale structure with only a small amount of them,is a promising ***,for real systems,networks with multiple nodes are normally required to monitor large-scale structures in a global way to identify any impact localization confliction,yet the existing studies are mostly evaluated with single nodes instead of ***,in this paper,based on a new low-power node designed,a Bluetooth-based digital impact monitoring PZT sensor network is proposed for the first time with its global confliction-solving impact localization *** of the system as a network are researched and analyzed on a complex real aircraft wing box for a global confliction-solving impact localization,showing a satisfying high accuracy.

关键词： Bluetooth-based low-power design Confliction-solving evaluation Complex composites Piezoelectric sensors Wireless impact monitoring network

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