检索结果-南通市图书馆

Broadband absorption performance of 3D-printed polyetheretherketone-based electromagnetic wave-absorbing composites

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第8期37卷 547-558页

作者： Lin BAI Nan CHANG Meiying ZHAO Chi hou yi CAO Dichen LI School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Chengdu Aircraft Design and Research Institute Chengdu 610091China Xi’an Key Laboratory of Advanced Structure Design and Application of Aircraft Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory for Manufacturing System Engineering Xi’an Jiaotong UniversityXi’an 710054China

The rapid development of additive manufacturing technology has offered a new avenue for designing and fabricating high wave-absorbing meta *** this study,the mechanical properties and broadband absorption performance of Poly-Ether-Ether-Ketone(PEEK)–based electromagnetic wave–absorbing composite materials was *** high-performance polymer PEEK was used as the matrix,and the materials with electromagnetic wave loss,such as reduced graphene oxide,Carbonyl Iron(CI),and Flake CI(FCI),were used as *** on the theory of impedance matching,a wave-absorbing structure with a gradual impedance gradient was designed and *** test results showed that at the 2.0–18.0 GHz frequency band,the coverage rate of the effective absorption bandwidth was up to 72.0%,the average optimal reflectivity was–18.09 dB,and the wide-angle absorption range was 0°–30°.The advantages of additive manufacturing technology in designing and fabricating wave-absorbing structures are presented,demonstrating that the technology is an effective method for creating broadband absorbing structures.

关键词： Absorption performance Additive manufacturing Electromagnetic absorption PEEK composite materials Gradual structure Broadband absorption

A global model for evaluating discharge characteristics and performance of hollow cathodes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第9期37卷 72-84页

作者： feng TIAN Long MIAO Qimeng XIA Zhiwen WU Ningfei WANG Xiao hou School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Chongqing Innovation Center Beijing Institute of TechnologyChongqing 404100China

Hollow cathode,with the highest plasma density,current density,and temperature,becomes one of the most important components in the electro-thruster *** the electric-propulsion thruster performance is directly related to the ionization rate,reliability,and lifetime of the hollow cathode,this paper develops a global model to study the effects of discharge current,gas flow rate,and gas species on the discharge characteristics in the insert and orifice regions of the hollow *** emitter wall temperatures of hollow cathodes predicted by the global model are compared with experimental results from NSTAR thruster neutralization cathodes,confirming the model's *** influence of hollow cathode emitter material and structure sizes on the plasma parameters in the internal regions was also *** simulation results show that there is an optimal matching relationship between the discharge current and gas flow rate to guarantee the maximum ionization *** optimal working region for the hollow cathode has been deter-mined under different energetic,regime and structural *** global model established in this paper can quickly determine the key structure and operating parameters of hollow cathode at the design stage,and provide the theoretical basis for hollow cathode design and development.

关键词： Hollow cathode Global model Electric propulsion Discharge characteristics Optimal matching relationship

Characteristics of the HIV/AIDS Epidemic among People Aged≥50 Years in China during 2018–2021

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2024年第4期37卷 399-405页

作者： hou Yu Shan JIN yi Chen CAI Chang TANG hou Lin QIN Qian Qian LYU Fan National Center for AIDS/STD Control and Prevention Chinese Center for Disease Control and PreventionBeijing 102206China

Objective This study aimed to determine the current epidemiological status of PLWHA aged≥50 years in China from 2018 to *** also aimed to recommend targeted interventions for the prevention and treatment of HIV/AIDS in elderly *** Data on newly reported cases of PLWHA,aged≥50 years in China from 2018 to 2021,were collected using the *** tests and spatial analyses were also *** Between 2018 and 2021,237,724 HIV/AIDS cases were reported among patients aged≥50 years in *** main transmission route was heterosexual transmission(91.24%).Commercial heterosexual transmission(CHC)was the primary mode of transmission among males,while non-marital non-CHC([NMNCHC];60.59%)was the prevalent route in *** proportion of patients with CHC decreased over time(Z=67.716,P<0.01),while that of patients with NMNCHC increased(Z=153.05,P<0.01).The sex ratio varied among the different modes of infection,and it peaked at 17.65 for *** spatial analysis indicated spatial clustering,and the high-high clustering areas were mainly distributed in the southwestern and central-southern *** In China,PLWHA,aged≥50 years,were predominantly infected through heterosexual *** primary modes of infection were CHC and *** were variations in the sex ratio among different age groups,infected through various sexual ***/AIDS cases exhibited spatial *** on these results,the expansion of HIV testing,treatment,and integrated behavioral interventions in high-risk populations is recommended to enhance disease detection in key regions.

关键词： HIV/AIDS Aged≥50 years China

Understanding the Interfacial Energy Structure and Electron Extraction Process in Inverted Organic Solar Cells with Phosphine-Doped Cathode Interlayers

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第12期42卷 1347-1354页

作者： yi Yang Jingwen Wang Yang Xiao Bowei Xu Jianhui hou State Key Laboratory of Polymer Physics and Chemistry Beijing National Laboratory for Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China State Key Laboratory of Chemical Resource Engineering College of Materials Science and EngineeringBeijing University of Chemical TechnologyBejing 100029China University of Chinese Academy of Sciences Beijing 100049China

Comprehensive Summary Cathode interlayers(CILs)play an essential role in achieving efficient organic solar cells(OSCs).However,the electronic structure at the electrode/CIL/active layer interfaces and the underlying mechanisms for electron collection remain unclear,which becomes a major obstacle to develop high-performance ***,we investigate the relationship of the electron collection abilities of four cross-linked and n-doped CILs(c-NDI:P0,c-NDI:P1,c-NDI:P2,c-NDI:P3)with their electronic structure of space charge region at heterojunction *** accurately calculating the depletion region width according to the barrier height,doping density and permittivity,we put forward that the optimal thickness of CIL should be consistent with the depletion region width to realize the minimum energy *** a result,the depletion region width is largely reduced from 13 nm to 0.8 nm at the indium tin oxide(ITO)/c-NDI:P0 interface,resulting in a decent PCE of 17.7%for the corresponding inverted OSCs.

关键词： Organic solar cells Cathode interlayer Depletion region width Electric conductivity Electron transport Electron transfer Electron extraction process

Rapid synthesis of oxygen-defected molybdenum oxides quantum dots as efficient nanozymes for healing diabetic ulcers

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 2024年第7期17卷 6376-6385页

作者： Fangjun Cao Hui feng Jiaxin Yao Xiang hou Tiezhi Jin Junfeng Hui Shaanxi Key Laboratory of Qinling Ecological Security Shaanxi Institute of ZoologyXi’an 710072China Engineering Research Center of Western Resource Innovation Medicine Green Manufacturing Ministry of EducationSchool of Chemical EngineeringNorthwest UniversityXi'an 710069China Shaanxi Key Laboratory of Degradable Biomedical Materials and Shaanxi R&D Center of Biomaterials and Fermentation Engineering School of Chemical EngineeringNorthwest UniversityXi'an 710069China

The continuous inflammatory response in diabetic skin wounds leads to excessive production of reactive oxygen species,which cause a vicious circle of long-term *** the therapeutic research of metal nanoenzymes for healing diabetic ulcers,it still faces the challenges in poor nanoenzymes activity and low-efficient therapeutic ***,ultrasmall oxygen-deficient MoO_(3−X)quantum dots were fabricated and employed as nanoenzymes for healing fiabetic *** PEGylation,PEGylated MoO_(3−X)quantum dots(MoO_(3−X)/PEG)with oxygen vacancies exhibits excellent photothermal,peroxidase/catalase-like *** addition,these MoO_(3−X)/PEG showed superior properties in scavenging H_(2)O_(2)and effectively inhibiting the scavenging of reactive oxygen *** importantly,such an oxygen-defected MoO_(3−X)/PEG had obvious antibacterial and skin repairing effects on alleviating hypoxia and excessive oxidative stress even in a mouse model of diabetic ulcers,inhibiting proinflammatory cytokines and significantly accelerating the healing of infected wounds,which shows great application potential for promoting wound *** work highlights that the developed oxygen defected molybdenum oxide compounds capable of peroxidaselike and catalase-like activities show great application potential for healing diabetes wound.

关键词： oxygen-defected molybdenum-based nanoenzymes antioxidant anti-inflammatory diabetes ulcer wounds

Enhanced electrochemical oxidation of perfluorooctanoic acid on Ti/SnO_(2)-Sb electrode by surface morphology regulation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第3期35卷 140-143页

作者： Kaiqiang hou Genwang Zhu Yujie feng Yanming Liu Xie Quan Key Laboratory of Industrial Ecology and Environmental Engineering(Ministry of Education China)School of Environmental Science and TechnologyDalian University of TechnologyDalian 116024China State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin 150090China

Electrochemical oxidation is an effective method to degrade persistent organic ***,due to the limited catalytic activity of traditional thin film electrodes,the anodic oxidation process is slow and usually requires high energy ***,Ti/SnO_(2)-Sb electrode with regulated surface structure was reported to enhance the performance for electrochemical oxidation of persistent organic *** electrode deposited with SnO_(2)-Sb nanoneedles(Ti/N-SnO_(2)-Sb)showed higher oxidation *** kinetic constant for perfluorooctanoic acid(PFOA)oxidation was 2.0 h^(-1)and the total organic carbon removal rate was 81.7%(4 h)at a relatively low current density of 6 mA/cm^*** with Ti/SnO_(2)-Sb thin film and nanoparticles,Ti/N-SnO_(2)-Sb significantly improved the electrochemical active area and·OH yield,and simultaneously reduced the electron transfer resistance,which enabled it to oxidize PFOA more rapidly even at a lower *** work provides a new strategy for promoting the electrochemical oxidation performance.

关键词： Electrochemical oxidation Nanoneedle SnO_(2)-Sb Perfluoroalkyl compounds Electrochemical degradation Persistent organic pollutants

Pure quantum gradient descent algorithm and full quantum variational eigensolver

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2024年第2期19卷 221-234页

作者： Ronghang Chen Zhou Guang Cong Guo Guanru feng Shi-Yao hou College of Physics and Electronic Engineering Center for Computational SciencesSichuan Normal UniversityChengdu 610068China Shenzhen SpinQ Technology Co. Ltd.Shenzhen 518045China DEEPROUTE.AI

Optimization problems are prevalent in various fields,and the gradient-based gradient descent algorithm is a widely adopted optimization ***,in classical computing,computing the numerical gradient for a function with variables necessitates at least d+1 function evaluations,resulting in a computational complexity of O(d).As the number of variables increases,the classical gradient estimation methods require substantial resources,ultimately surpassing the capabilities of classical ***,leveraging the principles of superposition and entanglement in quantum mechanics,quantum computers can achieve genuine parallel computing,leading to exponential acceleration over classical algorithms in some *** this paper,we propose a novel quantum-based gradient calculation method that requires only a single oracle calculation to obtain the numerical gradient result for a multivariate *** complexity of this algorithm is just O(1).Building upon this approach,we successfully implemented the quantum gradient descent algorithm and applied it to the variational quantum eigensolver(VQE),creating a pure quantum variational optimization *** with classical gradient-based optimization algorithm,this quantum optimization algorithm has remarkable complexity advantages,providing an efficient solution to optimization *** proposed quantum-based method shows promise in enhancing the performance of optimization algorithms,highlighting the potential of quantum computing in this field.

关键词： quantum algorithm gradient descent variational quantum algorithm

Self assembled electron blocking and lithiophilic interface towards dendrite-free solid-state lithium battery

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第4期35卷 220-225页

作者： Caixia Li yi Qiu Yufeng Zhao Wuliang feng Institute for Sustainable Energy&College of Sciences Shanghai UniversityShanghai 200444China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin 300071China

The poor interfacial contact is one of the biggest challenges that solid-state lithium batteries suffer *** the solid-state electrolyte surface energy by transforming the interface from lithiophobic to lithiophilic is effective to promote the interfacial contact, but electronic conductive interphases usually increase the risk of electron attack, thus leading to uncontrollable Li dendrite growth. Herein, we propose a self-assembled thermodynamic stable Li I interphase to simultaneously improve the interfacial contact between the garnet electrolyte Li_7La_(3)Zr_(2)O_(12)(LLZO) and Li anode, and prohibit the electron attack. The direct contact between LLZO and Li and the high temperature Li melting process was ascribed to Zr4+reduction, which facilitated Li dendrite formation and propagation. With the modification of the high lithiophilic I_(2) thin film, the area specific interfacial resistance of LLZO/Li was reduced from 1525 Ω/cm^(2) to 57 Ω/cm^(2). More importantly, LLZO was protected from being reduced due to the outstanding electronic insulativity of the Li I interphase, which leaded to a high critical current density of 1.2/7.0 m A/cm^(2) in the time/capacity-constant modes, respectively.

关键词： Li_7La_(3)Zr_(2)O_(12) LiI interphase Interfacial contact Li dendrite Thermodynamic stable

A real-time intelligent lithology identification method based on a dynamic felling strategy weighted random forest algorithm

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 1135-1148页

作者： Tie Yan Rui Xu Shi-Hui Sun Zhao-Kai hou Jin-Yu feng School of Petroleum Engineering Northeast Petroleum UniversityDaqing163318HeilongjiangChina Sanya Offshore Oil&Gas Research Institute Northeast Petroleum UniversitySanya572025HainanChina

Real-time intelligent lithology identification while drilling is vital to realizing downhole closed-loop drilling. The complex and changeable geological environment in the drilling makes lithology identification face many challenges. This paper studies the problems of difficult feature information extraction,low precision of thin-layer identification and limited applicability of the model in intelligent lithologic identification. The author tries to improve the comprehensive performance of the lithology identification model from three aspects: data feature extraction, class balance, and model design. A new real-time intelligent lithology identification model of dynamic felling strategy weighted random forest algorithm(DFW-RF) is proposed. According to the feature selection results, gamma ray and 2 MHz phase resistivity are the logging while drilling(LWD) parameters that significantly influence lithology identification. The comprehensive performance of the DFW-RF lithology identification model has been verified in the application of 3 wells in different areas. By comparing the prediction results of five typical lithology identification algorithms, the DFW-RF model has a higher lithology identification accuracy rate and F1 score. This model improves the identification accuracy of thin-layer lithology and is effective and feasible in different geological environments. The DFW-RF model plays a truly efficient role in the realtime intelligent identification of lithologic information in closed-loop drilling and has greater applicability, which is worthy of being widely used in logging interpretation.

关键词： Intelligent drilling Closed-loop drilling Lithology identification Random forest algorithm Feature extraction