检索结果-南通市图书馆

An anti-collision algorithm for robotic search-and-rescue tasks in unknown dynamic environments

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2024年第4期25卷 569-584页

作者： Yang CHEN Dianxi SHI Huanhuan YANG Tongyue li zhen WANG School of Computer Science Peking UniversityBeijing 100871China Tianjin Artificial Intelligence Innovation Center Tianjin 300457China Intelligent Game and Decision Lab Beijing 100071China College of Computer National University of Defense TechnologyChangsha 410073China

This paper deals with the search-and-rescue tasks of a mobile robot with multiple interesting targets in an unknown dynamic *** problem is challenging because the mobile robot needs to search for multiple targets while avoiding obstacles *** ensure that the mobile robot avoids obstacles properly,we propose a mixed-strategy Nash equilibrium based Dyna-Q(MNDQ)***,a multi-objective layered structure is introduced to simplify the representation of multiple objectives and reduce computational *** structure divides the overall task into subtasks,including searching for targets and avoiding ***,a risk-monitoring mechanism is proposed based on the relative positions of dynamic *** mechanism helps the robot avoid potential collisions and unnecessary ***,to improve sampling efficiency,MNDQ is presented,which combines Dyna-Q and mixed-strategy Nash *** using mixed-strategy Nash equilibrium,the agent makes decisions in the form of probabilities,maximizing the expected rewards and improving the overall performance of the Dyna-Q ***,a series of simulations are conducted to verify the effectiveness of the proposed *** results show that MNDQ performs well and exhibits robustness,providing a competitive solution for future autonomous robot navigation tasks.

关键词： Search and rescue Reinforcement learning Game theory Collision avoidance Decision-making

NIR-IIb-triggered photodynamic therapy combined with chemotherapy platform based on rare-earth-doped nanoparticles

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第7期43卷 3220-3231页

作者： Zhuo Tu Yong Wan Juan Ge Chen-Chen li Tao liang zhen li Chemistry and Chemical Engineering Hubei UniversityWuhan 430062China

Photodynamic therapy(PDT),with high spatiotemporal selectivity,minimal side effects and less drug resistance,has emerged as a promising approach for the treatment of ***,inadequate penetration depth and poor efficacy seriously restrict its practical *** address these challenges,we developed a combined therapy platform(RENP@C/D-FA)based on rare-earth-doped nanoparticles(RENPs)with a structure of NaErF_(4):Tm(0.5%)@NaYF_(4),on which photosensitizer Ce6(chlorin e6)and chemo-therapeutic drug(DOX)(doxorubicin)were loaded by encapsulating with an amphiphilic polymer distearoyl phosphatidylethanolamine-polyethylene glycol-folic acid(DSPE-PEG-FA).RENPs with NaErF_(4) as the matrix possess multiple excitation/emission peaks,enabling activation of PDT under near-infrared-Ⅱb(NIR-Ⅱb,1500-1700 nm)excitation and luminescence imaging in NIR-Ⅱb region by absorbing 808 nm near-infrared ***,DOX can be selectively released in the acidic microenvironment of *** from the tumor targeting capability of folic acid,this platform can successfully ablate tumor cells and inhibit tumor growth by combining PDT and *** innovative approach holds great promise as a powerful tool for cancer treatment,showing the potential to revolutionize PDT.

关键词： Photodynamic therapy Rare-earth-doped nanoparticles NIR-IIb Chemotherapy Combined therapy

Will partial splenic embolization followed by splenectomy increase intraoperative bleeding?

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Surgery 2024年第2期16卷 318-330页

作者： Long Huang Qing-lin li Qing-Sheng Yu hui Peng Zhou zhen Yi Shen Qi Zhang Department of No.1 Surgery The First Hospital Affiliated to Anhui University of Traditional Chinese MedicineHefei 230031Anhui ProvinceChina Anhui University of Traditional Chinese Medicine Anhui University of Traditional Chinese MedicineHefei 230038Anhui ProvinceChina Department of Surgery The Second Hospital Affiliated to Anhui University of Traditional Chinese MedicineHefei 230061Anhui ProvinceChina

BACKGROUND Partial splenic embolization(PSE)has been suggested as an alternative to splenectomy in the treatment of ***,some patients may experience recurrence of hypersplenism after PSE and require ***,there is a lack of evidence-based medical support regarding whether preoperative PSE followed by splenectomy can reduce the incidence of *** To investigate the safety and therapeutic efficacy of preoperative PSE followed by splenectomy in patients with cirrhosis and *** Between January 2010 and December 2021,321 consecutive patients with cirrhosis and hypersplenism underwent splenectomy at our *** on whether PSE was performed prior to splenectomy,the patients were divided into two groups:PSE group(n=40)and non-PSE group(n=281).Patient characteristics,postoperative complications,and follow-up data were compared between *** score matching(PSM)was conducted,and univariable and multivariable analyses were used to establish a nomogram predictive model for intraoperative bleeding(IB).The receiver operating characteristic curve,Hosmer-Lemeshow goodness-of-fit test,and decision curve analysis(DCA)were employed to evaluate the differentiation,calibration,and clinical performance of the *** After PSM,the non-PSE group showed significant reductions in hospital stay,intraoperative blood loss,and operation time(all P=0.00).Multivariate analysis revealed that spleen length,portal vein diameter,splenic vein diameter,and history of PSE were independent predictive factors for IB.A nomogram predictive model of IB was constructed,and DCA demonstrated the clinical utility of this *** groups exhibited similar results in terms of overall survival during the follow-up *** Preoperative PSE followed by splenectomy may increase the incidence of IB and a nomogram-based prediction model can predict the occurrence of IB.

关键词： Partial splenic embolization Splenectomy Hypertension,Portal liver Cirrhosis Intraoperative bleeding

Genetic identification for routine diagnosis of HBV by dot-blot hybridization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中华医学杂志(英文版) 1993年第7期106卷 551-551页

作者： Wang Bo-yun li Yu-song Peng Wei-dan Zhang Zu-xi li hui-zhen Department of Pathology Fourth Military Medical University Xi'an 710032 Xi'an Second People's Hospital Xi'an

Central cell:the key to determine persistent pollen tube attraction or termination

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(life Sciences) 2024年第9期67卷 2030-2032页

作者： Jiang-Guo Meng Shi-zhen li Hong-Ju li Center for Developmental Biology Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation Integrative Science Center of Germplasm Creation Western China(Chongqing)Science CitySchool of Life SciencesSouthwest UniversityChongqing400715 China Key Laboratory of Seed Innovation Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China Center for Molecular Agrobiology Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China

Most eukaryotic species depend on sexual reproduction,characterized by fertilization,to produce a new *** process requires the transfer of sperm(male gamete),containing half of the genetic information,from the male to the egg cell(female gamete),which holds half of the maternal genome,within the female reproductive *** strategies have been evolved to ensure fertilization success in plants.

关键词： organs termination holds

Optical and electrical anisotropy regulation engineering of low-dimensional materials toward polarized detection and imaging applications

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第7期43卷 2968-2993页

作者： Jian-Bin Zhang Nan Zhou li-hui Zhang Cong-hui Shang Jia-Xuan li Yi Zhao Guo-hui Jia Ru-Sen Yang Hua Xu Xiao-Bo li Shaanxi Joint Key Laboratory of Graphene Shaanxi Key Laboratory of High-Orbits-Electron Materials and Protection Technology for AerospaceShaanxi Joint Key Laboratory of GrapheneSchool of Advanced Materials and NanotechnologyXidian UniversityXi'an710126China Guangzhou Institute of Technology Xidian UniversityGuangzhou 710068China Xi'an Thermal Power Research Institute Co. LtdXi'an 710054China Key Laboratory of Applied Surface and Colloid Chemistry Ministry of EducationShaanxi Key Laboratory for Advanced Energy DevicesShaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science and EngineeringShaanxi Normal UniversityXi'an Xi'an 710119China

Polarized-sensitive image sensors are a kind of photodetector with great development potential due to their enhanced ability to detect and identify the target objects from the aspect of spatial,spectral and polarized ***,low-dimensional anisotropic materials with inherent anisotropic properties,ultrathin thickness,tunable bandgap and feasible integration with complementary metal oxide semiconductor(CMOS)fabrication processes have attracted great interest for their facilitation of polarized photodetector devices *** the polarized detection performance of low-dimensional materials to satisfy realistic needs stimulates the exploration of modulation of anisotropic *** this review,we comprehensively introduce the latest research progress in modulating the optical and optoelectronic anisotropy characteristics of low-dimensional *** strategy of anisotropy regulation through crystal structure engineering and coupling system is discussed ***,the latest progress in image recognition applications using anisotropic low-dimensional materials is reviewed in ***,we summarize the challenge and propose future opportunities in the practical application of polarized-sensitive imaging photodetectors based on low-dimensional anisotropic materials.

关键词： Anisotropy Polarized detection Image recognition Low-dimensional materials

Effects of physical properties of supercritical water on heat transfer characteristics of single particle within a particle cluster Author links open overlay panel

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第8期91卷 291-302页

作者： Xiaoyu li Bowei Zhang huibo Wang hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710049China

The complex physical properties of supercritical water(SCW)make the heat transfer characteristics of particles within a particle cluster *** heat transfer characteristics of single particle within a particle cluster in SCW,influenced by surrounding particles,have not been effectively *** numerical simulations were conducted to investigate the heat transfer characteristics of particle clusters in SCW under different *** results were compared and analyzed with those from constant property *** was found that Reynolds number(Re)and the void fraction of particle cluster have no special effects on the variation trends of Nusselt number(Nu)for the focused ***,the particle temperature had a significant effect on the variation trends of *** effect of Re on the heat transfer rate exponent(η)of the focused particle can be divided into two zones:a significant effect zone and a non-significant effect *** effect of void fraction onηin the non-significant effect zone was *** the non-significant effect zone,ηdecreased with the increasing particle *** the significant effect zone,the variation trends ofηbecame more *** fundamental reason for this series of phenomena is the changes in distribution of physical properties.A model forηwas developed for the non-significant effect *** model can filter out the effects of Re and certain particle cluster spatial configurations,and it demonstrates good predictive performance.

关键词： Supercritical water Particle cluster Heat transfer characteristics Heat transfer rate exponent Physical properties correction

Vision-Based Adaptive Prescribed-Time Control of UAV for Uncooperative Target Tracking with Performance Constraint

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 Systems Science & Complexity 2024年第5期37卷 1956-1977页

作者： SHE Xuehua MA hui REN Hongru li Hongyi School of Automation and the Guangdong Provincial Key Laboratory of Intelligent Decision and Cooperative Control Guangdong University of Technology School of Mathematics and Statistics Guangdong University of Technology College of Electronic and Information Engineering and Chongqing Key Laboratory of Generic Technology and System of Service Robots Southwest University

This paper discusses the uncooperative target tracking control problem for the unmanned aerial vehicle(UAV) under the performance constraint and scaled relative velocity constraint, in which the states of the uncooperative target can only be estimated through a vision sensor. Considering the limited detection range, a prescribed performance function is designed to ensure the transient and steady-state performances of the tracking system. Meanwhile, the scaled relative velocity constraint in the dynamic phase is taken into account, and a time-varying nonlinear transformation is used to solve the constraint problem, which not only overcomes the feasibility condition but also fails to violate the constraint boundaries. Finally, the practically prescribed-time stability technique is incorporated into the controller design procedure to guarantee that all signals within the closed-loop system are *** is proved that the UAV can follow the uncooperative target at the desired relative position within a prescribed time, thereby improving the applicability of the vision-based tracking approach. Simulation results have been presented to prove the validity of the proposed control strategy.

关键词： Nonlinear transformation performance constraint prescribed-time tracking uncooperative target vision-based measurement

Machine Learning-based Identification of Contaminated Images in light Curve Data Preprocessing

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第4期24卷 287-295页

作者： hui li Rong-Wang li Peng Shu Yu-Qiang li Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Space Object and Debris Observation Chinese Academy of SciencesNanjing 210023China

Attitude is one of the crucial parameters for space objects and plays a vital role in collision prediction and debris *** light curves to determine attitude is the most commonly used *** photometric observations,outliers may exist in the obtained light curves due to various ***,preprocessing is required to remove these outliers to obtain high quality light *** statistical analysis,the reasons leading to outliers can be categorized into two main types:first,the brightness of the object significantly increases due to the passage of a star nearby,referred to as“stellar contamination,”and second,the brightness markedly decreases due to cloudy cover,referred to as“cloudy contamination.”The traditional approach of manually inspecting images for contamination is time-consuming and ***,we propose the utilization of machine learning methods as a *** Neural Networks and SVMs are employed to identify cases of stellar contamination and cloudy contamination,achieving F1 scores of 1.00 and 0.98 on a test set,*** also explore other machine learning methods such as ResNet-18 and light Gradient Boosting Machine,then conduct comparative analyses of the results.

关键词： techniques:image processing methods:data analysis light pollution