检索结果-南通市图书馆

Multi-scale collaborative design method for macroscopic thermal optimization and mesoscopic woven structure of hypersonic vehicle's TOCMC leading edge

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第4期37卷 524-541页

作者： Chenwei ZHAO Zecan TU Junkui mao Jian HUI Pingting CHEN College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 21016China Integrated Energy Institute Nanjing University of Aeronautics and AstronauticsNanjing 210016China

A new thermal protection design method for hypersonic vehicle's leading edge is proposed, which can effectively reduce temperature of the leading edge without additional cooling measures. This method reduces the leading-edge's temperature by the multi-scale collaborative design of the macroscopic thermal optimization and the mesoscopic woven structures of Three-dimensional Orthogonal Woven Ceramic Matrix Composites(TOCMC). The macroscopic thermal optimization is achieved by designing different mesoscopic woven structures in different regions to create combined heat transfer channels to dredge the heat. The combined heat transfer channel is macroscopically represented by the anisotropic thermal conductivity of TOCMC. The thermal optimization multiple linear regression model is established to optimize the heat transport channel, which predicts Theoretical Optimal Thermal Conductivity Configuration(TOTCC) in different regions to achieve the lowest leading-edge temperature. The function-oriented mesostructure design method is invented to design the corresponding mesostructure of TOCMC according to the TOTCC, which consists of universal thermal conductivity prediction formulas for TOCMC. These universal formulas are firstly derived based on the thermal resistance network method, which is verified by experiments with an error of 6.25%. The results show that the collaborative design method can effectively reduce the leading edge temperature by about 12.8% without adding cooling measures.

关键词： Multi-scale collaborative design Thermal optimization Ceramic matrix composite Hypersonic vehicle Thermal protection Intelligent optimization

Mechanical properties and fracture surface roughness of thermally damaged granite under dynamic splitting

在线全文

学校读者我要写书评

暂无评论

deep Underground Science and Engineering 2024年第1期3卷 103-116页

作者： Yijin Qian Peng Jia Songze mao Jialiang Lu School of Resources and Civil Engineering Northeastern UniversityShenyangChina

In order to understand the mechanical properties and the fracture surface roughness characteristics of thermally damaged granite under dynamic splitting,dynamic Brazilian splitting tests were conducted on granite samples after thermal treatment at 25,200,400,and 600℃.Results show that the dynamic peak splitting strength of thermally damaged granite samples increases with increasing strain rate,showing obvious strain‐rate *** increasing temperature,thermally induced cracks in granite transform from intergranular cracks to intragranular cracks,and to a transgranular crack *** induced damages reduce the dynamic peak splitting strength and the maximum absorbed energy while increasing the peak radial *** fracture mode of the thermally damaged granite under dynamic loads is mode Ⅱ splitting *** using the axial roughness index Z2 a,the distribution ranges of the wedge‐shaped failure zones and the tensile failure zones in the fracture surfaces under dynamic Brazilian splitting can be effectively *** radial roughness index Z_(2)^(r)is sensitive to the strain rate and *** shows a linear correlation with the peak splitting strength and the maximum absorbed energy and a linear negative correlation with the peak radial strain.Z_(2)^(r)can be used to quantitatively estimate the dynamic parameters based on the models proposed.

关键词： dynamic splitting fracture surface roughness granite strain rate thermal treatment

Comparison of the Minimum Bounding Rectangle and Minimum Circumscribed Ellipse of Rain Cells from TRMM

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2024年第3期41卷 391-406页

作者： Hongke CAI Yaqin mao Xuanhao ZHU Yunfei FU Renjun ZHOU Plateau Atmospheric and Environment Laboratory of Sichuan Province School of Atmospheric SciencesChengdu University of Information TechnologyChengdu 610225China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Center for Atmospheric Optics Anhui Institute of Optics and Fine MechanicsChinese Academy of SciencesHefei 230031China

Based on the TRMM dataset, this paper compares the applicability of the improved MCE(minimum circumscribed ellipse), MBR(minimum bounding rectangle), and DIA(direct indexing area) methods for rain cell fitting. These three methods can reflect the geometric characteristics of clouds and apply geometric parameters to estimate the real dimensions of rain cells. The MCE method shows a major advantage in identifying the circumference of rain cells. The circumference of rain cells identified by MCE in most samples is smaller than that identified by DIA and MBR, and more similar to the observed rain cells. The area of rain cells identified by MBR is relatively robust. For rain cells composed of many pixels(N> 20), the overall performance is better than that of MCE, but the contribution of MBR to the best identification results,which have the shortest circumference and the smallest area, is less than that of MCE. The DIA method is best suited to small rain cells with a circumference of less than 100 km and an area of less than 120 km^(2), but the overall performance is mediocre. The MCE method tends to achieve the highest success at any angle, whereas there are fewer “best identification”results from DIA or MBR and more of the worst ones in the along-track direction and cross-track direction. Through this comprehensive comparison, we conclude that MCE can obtain the best fitting results with the shortest circumference and the smallest area on behalf of the high filling effect for all sizes of rain cells.

关键词： TRMM minimum bounding rectangle minimum circumscribed ellipse

Alkaline zinc-based flow battery: chemical stability, morphological evolution, and performance of zinc electrode with ionic liquid

在线全文

学校读者我要写书评

暂无评论

Frontiers of Materials Science 2024年第1期18卷 113-121页

作者： Tianyong mao Jing Dai Meiqing Xin deliang Zeng Zhipeng Xie Jiangxi Province Key Laboratory of Power Batteries and Materials Jiangxi University of Science and TechnologyGanzhou 341000China

Zinc-based flow battery is an energy storage technology with good application prospects because of its advantages of abundant raw materials,low cost,and environmental *** chemical stability of zinc electrodes exposed to electrolyte is a very important issue for zinc-based *** paper reports on details of chemical stability of the zinc metal exposed to a series of solutions,as well as the relationship between the morphological evolution of zinc electrodes and their properties in an alkaline *** corrosion of zinc electrodes by the electrolyte will change their surface ***,we observed that chemical corrosion is not the main contributor to the evolution of zinc electrode surface morphology,but the main contributor is the Zn/Zn^(2+)electrode *** morphological evolution of zinc electrodes was controlled by using ionic liquids,1-ethyl-3-methylimidazolium acetate(EMIA),and 1-propylsulfonic-3-methylimidazolium tosylate(PSMIT),and the electrode performance was recorded during the morphological evolution *** was observed that the reversible change of zinc electrode morphology was accompanied by better electrode performance.

关键词： alkaline medium morphological evolution zinc-based flow battery new energy

Global Research Progress on Municipal Waste and Future Prospect Based on the Cross-national Comparisons

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 Geographical Science 2024年第2期34卷 250-264页

作者： ZHANG Yuxin LIU Xiaoqian YAN Xiaoxia MA Sike mao Weiyun College of Applied Arts and Science of Beijing Union University Beijing 100191China

Due to the acceleration of urbanization,the municipal waste(MW)problem has transformed into a global challenge for urb-an *** elucidate historical trends,current focal points,and future directions in MW research,we conducted a bibliometric analysis and employed knowledge graph visualization to scrutinize a total of 34212 articles,which were published between 1991 and 2021 in the Web of Science(WoS)core *** results indicated that current major research themes encompass waste classifica-tion and recycling,waste management and public behavior,waste disposal methods and technologies,as well as environmental impact and *** has been a shift in the research focus from the environmental impacts of waste incineration to sustainable manage-ment related issues.A comparison of research from six typical countries revealed the differences in research priorities and techniques *** from the USA and Britain initiated MW research earlier than other countries and investigated management issues in depth,such as public behavior and willingness to ***,Japanese,German,and Swedish scholars conducted extensive studies on advanced waste treatment technologies,such as disposal and recycling,risk assessment,and waste-to-energy *** scholars placed particular emphasis on end-of-pipe treatments and their associated environmental *** and poten-tial future frontiers were identified by burst detection *** with high value of burst index(BI)worldwide are food waste and circular *** scholars have put great efforts on waste environmental impact and its recycling technologies,while we’re expecting to further investigating vulnerable ***,this study contributes to bridging the regional gap of scientific research among different countries and fostering international collaboration.

关键词： bibliometrics municipal waste(MW) CiteSpace hotspot prediction burst index(BI) sustainability cross-national comparison Web of Science(WoS)

Shock-induced chemical reaction characteristics of PTFE-Al-Bi_(2)O_(3)reactive materials

在线全文

学校读者我要写书评

暂无评论

defence Technology（防务技术） 2024年第6期36卷 1-12页

作者： Chunlan Jiang Rong Hu Jingbo Zhang Zaicheng Wang Liang mao State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

A ternary system of PTFE/Al/Bi_(2)O_(3)is constructed by incorporating PTFE-based reactive material and thermite for enhancing the energy release of the PTFE-based reactive *** effects of Bi_(2)O_(3)in the PTFE/Al/Bi_(2)O_(3)on both mechanical properties and the energy release were investigated through various tests such as thermogravimetry-differential scanning calorimetry,adiabatic oxygen bomb test and split Hopkinson pressure bar *** microstructure observed through scanning electron microscope and Xray diffraction results are used to analyze the ignition and reaction mechanism of PTFE/Al/Bi_(2)O_(3).The results indicate that the PTFE/Al/Bi_(2)O_(3)are capable of triggering the exothermic reaction of molten PTFE/Bi_(2)O_(3)and Al/Bi_(2)O_(3)over the PTFE/Al reactive materials,thereby promoting *** excessive aluminum in the ternary system is beneficial for increasing energy *** ignition of shock-induced chemical reactions in PTFE/Al/Bi_(2)O_(3)is closely related to the material *** dominant mechanism for hot-spot generation under Split Hopkinson Pressure Bar test is the frictional temperature rise at the microcrack after failure.

关键词： PTFE/Al/Bi_(2)O_(3) Shock-induced chemical reaction Energy release

Extraordinary hot extreme in summer 2022 over the Yangtze River basin modulated by the La Nina condition under global warming

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2024年第1期15卷 21-30页

作者： Zhen LIAO Yu-Feng YUAN Yang CHEN Pan-mao ZHAI State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China

A widespread and prolonged hot extreme hit the Yangtze River basin in summer 2022,with 300 sites established new temperature records and nearly 96%stations endured more than 40 hot *** the perspective of the combination effect of the global warming and La Nina condition,potential mechanisms of the hot extreme were *** a record-breaking hot extreme was caused by an extremely strong and westward-shifted western Pacific subtropical high(WPSH).The global warming effect contributed primarily to the abnormal hot days in the Yangtze River basin,coupled with the modulation of the La Nina *** sea surface temperature anomaly pattern under La Nina condition favored more convection activities over the western Pacific,encouraging an enhanced and westward-extended *** addition,an observation-based attribution analysis indicates that anthropogenic warming may increase the probability of such extensively persistent hot extremeby1.8 times.

关键词： Hot extreme The Yangtze River basin Global warming Tropical Pacific forcing

Bioactive Hydrogels with Pro-coagulation Effect for Hemostasis

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 Chemistry 2024年第1期42卷 87-103,I0004页

作者： Quanshi Guo Yihang Ding Lisha Yu Zongrui Tong Zhengwei mao MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhouZhejiang 310058China department of Hepatobiliary and Pancreatic Surgery The Second Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouZhejiang 310009China Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province HangzhouZhejiang 310009China

Hemostatic hydrogels are widely applied for wound management of damaged tissues,traumatic wounds,and surgical *** hydrogels composed of bioactive components,including fibrin and thrombin,showed great promise in the clinic due to their good pro-coagulation *** the expanding knowledge of cascade reaction of blood coagulation and emerging bioactive substances,massive bioactive hydrogels consisting of peptides,hemocoagulase,polyphosphate(polyP),etc.,have been developed as effective hemostatic *** on the coagulation process and mechanism,we summarize the role of reported bioactive hydrogels in hemostasis in this *** conclude the key points in the coagulation process,including activation of coagulation factors,fibrinogen polymerization,etc.,then discuss how to design bioactive hydrogels to accelerate coagulation targeted to these ***,we conclude the progress and propose a perspective of bioactive hydrogels with a pro-coagulation effect for hemostasis.

关键词： Hemostasis Biological activity Biomaterials Enzyme catalysis Composites

Channel assignment and power allocation for throughput improvement with PPO in B5G heterogeneous edge networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Digital Communications and Networks 2024年第1期10卷 109-116页

作者： Xiaoming He Yingchi mao Yinqiu Liu Ping Ping Yan Hong Han Hu The College of Computer and Information Hohai UniversityNanjingChina The Key Laboratory of Water Big Data Technology of Ministry of Water Resources Hohai UniversityNanjing China The School of Computer Science and Engineering Nanyang Technological UniversitySingapore The College of Textile and Clothing Engineering Soochow UniversitySuzhouChina The College of Internet of Things Nanjing University of Posts and TelecomurunicationsNanjingChina

In Beyond the Fifth Generation(B5G)heterogeneous edge networks,numerous users are multiplexed on a channel or served on the same frequency resource block,in which case the transmitter applies coding and the receiver uses interference ***,uncoordinated radio resource allocation can reduce system throughput and lead to user inequity,for this reason,in this paper,channel allocation and power allocation problems are formulated to maximize the system sum rate and minimum user achievable *** the construction model is non-convex and the response variables are high-dimensional,a distributed deep Reinforcement Learning(DRL)framework called distributed Proximal Policy Optimization(PPO)is proposed to allocate or assign ***,several simulated agents are trained in a heterogeneous environment to find robust behaviors that perform well in channel assignment and power ***,agents in the collection stage slow down,which hinders the learning of other ***,a preemption strategy is further proposed in this paper to optimize the distributed PPO,form DP-PPO and successfully mitigate the straggler *** experimental results show that our mechanism named DP-PPO improves the performance over other DRL methods.

关键词： B5G Heterogeneous edge networks PPO Channel assignment Power allocation Throughput