检索结果-南通市图书馆

Deep reinforcement learning and its application in autonomous fitting optimization for attack areas of UCAVs

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 Engineering and Electronics 2020年第4期31卷 734-742页

作者： LI Yue QIU Xiaohui LIU Xiaodong XIA Qunli School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Science and Technology on Electro-Optic Control Laboratory Luoyang 471000China Beijing Aerospace Automatic Control Research Institute Beijing 100854China

The ever-changing battlefield environment requires the use of robust and adaptive technologies integrated into a reliable platform. Unmanned combat aerial vehicles(UCAVs) aim to integrate such advanced technologies while increasing the tactical capabilities of combat aircraft. As a research object, common UCAV uses the neural network fitting strategy to obtain values of attack areas. However, this simple strategy cannot cope with complex environmental changes and autonomously optimize decision-making problems. To solve the problem, this paper proposes a new deep deterministic policy gradient(DDPG) strategy based on deep reinforcement learning for the attack area fitting of UCAVs in the future battlefield. Simulation results show that the autonomy and environmental adaptability of UCAVs in the future battlefield will be improved based on the new DDPG algorithm and the training process converges quickly. We can obtain the optimal values of attack areas in real time during the whole flight with the well-trained deep network.

关键词： attack area neural network deep deterministic policy gradient(DDPG) unmanned combat aerial vehicle(UCAV)

The Importance of Flapping Kinematic Parameters in the Facilitation of the Different Flight Modes of Dragonflies

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2021年第2期18卷 419-427页

作者： xiaohui Liu Csaba Hefler Wei Shyy Huihe qiu Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and TechnologyHong Kong SARChina

To better understand dragonflies’remarkable flapping wing aerodynamic performance,we measured the kinematic parameters of the wings in two different flight modes(Normal Flight Mode(NFM)and Escape Flight Mode(EFM)).When the specimens switched from normal to escape mode the flapping frequency was invariant,but the stroke plane of the wings was more horizontally inclined.The flapping of both wings was adjusted to be more ventral with a change of the pitching angle that resulted in a larger angle of attack during downstroke and smaller during upstroke to affect the flow directions and the added mass effect.Noticeably,the phasing between the fore and hind pair of wings varies between two flight modes,which affects the wing-wing interaction as well as body oscillations.It is found that the momentum stream in the wake of EFM is qualitatively different from that in NFM.The change of the stroke plane angle and the varied pitching angle of the wings diverts the momentum downwards,while the smaller flapping amplitude and less phase difference between the wings compresses the momentum stream.It seems that in order to achieve greater flight maneuverability a flight vehicle needs to actively control positional angle as well as the pitching angle of the flapping wings.

关键词： wing kinematics flight mode dragonfly flight aerodynamics

Oxygen-defects evolution to stimulate continuous capacity increase in Co-free Li-rich layered oxides

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 Energy Chemistry 2023年第7期82卷 259-267,I0006页

作者： Yibin Zhang xiaohui Wen Zhepu Shi Bao qiu Guoxin Chen Zhaoping Liu Ningbo Institute of Materials Technology and Engineering(NIMTE) Chinese Academy of Sciences(CAS)Ningbo 315201ZhejiangChina School of Materials Science and Chemical Engineering Ningbo UniversityNingbo 315201ZhejiangChina Department of Chemical and Environmental Engineering Faculty of Science and EngineeringUniversity of Nottingham Ningbo Chin1Ningbo 315199ZhejiangChina

Though oxygen defects are associated with deteriorated structures and aggravated cycling performance in traditional layered cathodes,the role of oxygen defects is still ambiguous in Li-rich layered oxides due to the involvement of oxygen redox.Herein,a Co-free Li-rich layered oxide Li_(1.286)Ni_(0.071)Mn_(0.643)O_(2)has been prepared by a co-precipitation method to systematically investigate the undefined effects of the oxygen defects.A significant O_(2)release and the propagation of oxygen vacancies were detected by operando differential electrochemical mass spectroscopy(DEMS)and electron energy loss spectroscopy(EELS),respectively.Scanning transmission electron microscopy-high angle annular dark field(STEMHAADF)reveals the oxygen vacancies fusing to nanovoids and monitors a stepwise electrochemical activation process of the large Li_(2)MnO_(3)domain upon cycling.Combined with the quantitative analysis conducted by the energy dispersive spectrometer(EDS),existed nano-scale oxygen defects actually expose more surface to the electrolyte for facilitating the electrochemical activation and subsequently increasing available capacity.Overall,this work persuasively elucidates the function of oxygen defects on oxygen redox in Co-free Li-rich layered oxides.

关键词： Li-rich layered oxide Irreversible oxygen loss Nano-scale oxygen defect Li_(2)MnO_(3)-domain activation

Research progress on electrolytes for fast-charging lithium-ion batteries

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2023年第1期34卷 84-90页

作者： Dan Zhang Le Li Weizhuo Zhang Minghui Cao Hengwei qiu xiaohui Ji Shaanxi Key Laboratory of Catalysis School of Chemistry and Environment ScienceShaanxi University of TechnologyHanzhong 723001China Shaanxi Key Laboratory of Industrial Automation School of Mechanical EngineeringShaanxi University of TechnologyHanzhong 723001China School of Electronic and Information Engineering Qingdao UniversityQingdao 266071China Department of Chemistry Key Laboratory of Bioorganic Phosphorus Chemistry&Chemical BiologyTsinghua UniversityBeijing 100084China

Fast-charging is considered to be a key factor in the successful expansion and use of electric vehicles.Current lithium-ion batteries(LIBs)exhibit high energy density,enabling them to be used in electric vehicles(EVs)over long distances,but they take too long to charge.In addition to modifying the electrode and battery structure,the composition of the electrolyte also affects the fast-charging capability of LIBs.This review provides a comprehensive and in-depth overview of the research progress,basic mechanism,scientific challenges and design strategies of the new fast-charging solution system,focusing on the influences that the compositions of liquid and solid electrolytes have on the fast-charging performance of LIBs.Finally,new insights,promising directions and potential solutions for the electrolytes of fast-charging systems are proposed to stimulate further research on revolutionary next-generation fastcharging LIB chemistry.

关键词： Fast charging Lithium-ion battery Liquid electrolytes Solid-state electrolytes Salts Additive Solvent

Two-dimensional hybrid nanomaterials derived from MXenes(Ti3C2Tx)as advanced energy storage and conversion applications

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2020年第4期31卷 947-952页

作者： Sen Zhao Ravi Nivetha Yu qiu xiaohui Guo Key Lab of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education and the College of Chemistry and Materials ScienceNorthwest UniversityXi'an 710069China The State Key Laboratory of Solidification Processing in Northwestern Polytechnology University Xi'an 710012China

The development of two-dimensional hybrid nanomaterial derived from MXenes as high performance electrode material is the key component for the advanced ene rgy storage and conversion systems.In the past decades,MXene derived nanomaterials have attracted greatly interest in scientific activity and potential applications because of their unique synergistic properties such as high thermal stability,excellent electrical conductivity,large surface area,easy to handle and outstanding electro and photo chemical properties.This review is focused on the synthesis of hybrid nanomaterials from MXene(Ti3C2Tx)for renewable energy conversion and storage application including hydrogen evolution reaction,supercapacitor,lithium-ion batteries and photocatalysis.Finally,we also summarized the prospect and opportunities of novel two-dimensional hybrid nanomaterials derived MXene(Ti3C2Tx)fo r futuristic sustainable energy technology.

关键词： MXenes Hybrid nanomaterial Two-dimensional Energy storage Energy conversion

Preparation of Y^(3+)-doped Bi-_(2)MoO_(6) nanosheets for improved visible-light photocatalytic activity: Increased specific surface area, oxygen vacancy formation and efficient carrier separation

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2023年第9期30卷 1824-1834页

作者： Hong qiu Shujing Liu xiaohui Ma Yajie Li Yueyan Fan Wenjun Li Hualei Zhou Department of Chemistry and Chemical Engineering School of Chemistry and Biological EngineeringUniversity of Science and Technology BeijingBeijing 100083China College of Applied Science and Technology Beijing Union UniversityBeijing 100012China BGRIMM MTC Technology Co. Ltd.Beijing 102680China

Although Bi_(2)Mo O_(6)(BMO) has recently received extensive attention, its visible-light photocatalytic activity remains poor due to its limited photoresponse range and low charge separation efficiency. In this work, a series of visible-light-driven Y^(3+)-doped BMO(Y-BMO) photocatalysts were synthesized via a hydrothermal method. Degradation experiments on Rhodamine B and Congo red organic pollutants revealed that the optimal degradation rates of Y-BMO were 4.3 and 5.3 times those of pure BMO, respectively. The degradation efficiency of Y-BMO did not significantly decrease after four cycle experiments. As a result of Y^(3+)doping, the crystal structure of BMO changed from a thick layer structure to a thin flower-like structure with an increased specific surface area. X-ray photoelectron spectroscopy showed the presence of highintensity peaks for the O 1s orbital at 531.01 and 530.06 eV, confirming the formation of oxygen vacancies in Y-BMO. Photoluminescence(PL) and electrochemical impedance spectroscopy measurements revealed that the PL intensity and interface resistances of composites decreased significantly, indicating reduced electron–hole pair recombination. This work provides an effective way to prepare high-efficiency Bibased photocatalysts by doping rare earth metal ions for improved photocatalytic performance.

关键词： photocatalysts dye sensitization bismuth molybdate yttrium-doped

A case report of inverted Meckel’s diverticulum resected by single-balloon enteroscopy

在线全文

学校读者我要写书评

暂无评论

Gastroenterology Report 2022年第1期10卷 600-602页

作者： Li Zhang Lei Li Wenjie Yuan xiaohui Zhuang Chunya Wang Fengjiao qiu Department of Gastroenterology Affiliated Hospital of Weifang Medical UniversityWeifangShandongP.R.China

Introduction Meckel’s diverticulum(MD),which usually occurs in the distal ileum,is the most common congenital malformation of the gastrointestinal tract[1].MD is generally asymptomatic;however,-2%–6%of affected patients develop complications[2]such as bleeding,obstruction,or perforation.Intestinal hemorrhage is the most common complication,accounting for -30%of all complications[3].Laparoscopic surgery is usually recommended for MD with hemorrhagic complications.Inverted MD is very rare.MD was reportedly found by double-balloon enteroscopy and surgical treatment was performed.

关键词： balloon Meckel bleeding

Programming CAR T cells to enhance anti-tumor efficacy through remodeling of the immune system

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 Medicine 2020年第6期14卷 726-745页

作者： xiaohui Wang Zhiqiang Wu Wei qiu Ping Chen Xiang Xu Weidong Han College of Biotechnology Southwest UniversityChongqing 400715China State Key Laboratory of Trauma Burn and Combined InjuryDepartment of Stem Cell&Regenerative MedicineDaping Hospital and Research Institute of SurgeryChongqing 400042China Molecular&Immunological Department Bio-therapeutic DepartmentChinese PLA General HospitalBeijing 100853China

Chimeric antigen receptor(CAR)T cells have been indicated effective in treating B cell acute lymphoblastic leukemia and non-Hodgkin lymphoma and have shown encouraging results in preclinical and clinical studies.However,CAR T cells have achieved minimal success against solid malignancies because of the additional obstacles of their insufficient migration into tumors and poor amplification and persistence,in addition to antigen-negative relapse and an immunosuppressive microenvironment.Various preclinical studies are exploring strategies to overcome the above challenges.Mobilization of endogenous immune cells is also necessary for CAR T cells to obtain their optimal therapeutic effect given the importance of the innate immune responses in the elimination of malignant tumors.In this review,we focus on the recent advances in the engineering of CAR T cell therapies to restore the immune response in solid malignancies,especially with CAR T cells acting as cellular carriers to deliver immunomodulators to tumors to mobilize the endogenous immune response.We also explored the sensitizing effects of conventional treatment approaches,such as chemotherapy and radiotherapy,on CAR T cell therapy.Finally,we discuss the combination of CAR T cells with biomaterials or oncolytic viruses to enhance the anti-tumor outcomes of CAR T cell therapies in solid tumors.

关键词： CAR T cells immunoregulatory molecules endogenous immune response solid malignancies

Layer-dependent charge density wave phase transition stiffness in 1T-TaS_(2)nanoflakes evidenced by ultrafast carrier dynamics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2021年第4期14卷 1162-1166页

作者： Rui Wang Junbo Zhou Xinsheng Wang Liming Xie Jimin Zhao xiaohui qiu CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in NanoscienceNational Center for.Nanoscience and TechnologyBeijing 100190China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China University of Chinese Acadermy of Sciences Beijing 100049China

Novel physical properties emerge when the thickness of charge density wave(CDW)materials is reduced to the atomic level,owing to the significant modification of the electronic band structure and correlation effects.Here,we investigate the layer-dependent CDW phase transition and evolution of the nonequilibrium state of 1T-TaS_(2)nanoflakes using pump-probe spectroscopy.Both the low-energy single-particle and collective excitation relaxations exhibit sharp changes at〜210 K,indicating a phase transition from commensurate CDW to nearly commensurate CDW state.The single particle process reveals that the phase transition stiffness(PTS)is thickness-dependent.Moreover,a small PTS is observed in thin nanoflakes,which is attributed to the reduced thickness that increases the fluctuation and inhibits the nucleation and growth of discommensurations.In addition,the phase mode vanishes when the discommensuration network appears.Our results suggest that the carrier dynamics could be an efficient operational approach to measuring the quantum phase transition in correlated materials.

关键词： charge density wave 1T-TaS_(2) layer-dependent phase transition stiffness ultrafast carrier dynamics