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Mega-Constellations Based TT&C Resource Sharing: Keep Reliable Aeronautical Communication in an Emergency

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China Communications 2024年第2期21卷 1-16页

作者： Haoran Xie Yafeng zhan Jianhua lu Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

With the development of the transportation industry, the effective guidance of aircraft in an emergency to prevent catastrophic accidents remains one of the top safety concerns. Undoubtedly, operational status data of the aircraft play an important role in the judgment and command of the Operational Control Center(OCC). However, how to transmit various operational status data from abnormal aircraft back to the OCC in an emergency is still an open problem. In this paper, we propose a novel Telemetry, Tracking,and Command(TT&C) architecture named Collaborative TT&C(CoTT&C) based on mega-constellation to solve such a problem. CoTT&C allows each satellite to help the abnormal aircraft by sharing TT&C resources when needed, realizing real-time and reliable aeronautical communication in an emergency. Specifically, we design a dynamic resource sharing mechanism for CoTT&C and model the mechanism as a single-leader-multi-follower Stackelberg game. Further, we give an unique Nash Equilibrium(NE) of the game as a closed form. Simulation results demonstrate that the proposed resource sharing mechanism is effective, incentive compatible, fair, and reciprocal. We hope that our findings can shed some light for future research on aeronautical communications in an emergency.

关键词： aeronautical emergency communication mega-constellation networked TT&C resource allocation stackelberg game

Cobalt-Catalyzed Difunctionalization of Styrenes via Ligand Relay Catalysis

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Chinese Journal of Chemistry 2023年第24期41卷 3633-3638页

作者： Bingcheng Wang Yufeng Sun zhan lu Department of Chemistry Zhejiang UniversityHangzhouZhejiang310058 China College of Chemistry Zhengzhou UniversityZhengzhouHenan450001 China

Here,we report a cobalt-catalyzed sequential dehydrogenative Heck silylation/hydroamination of styrenes with hydrosilane and diazo compound to access 1-amino-2-silyl compounds with excellent *** difunctionalization reaction could undergo smoothly using 1 mol%catalyst loading with good functional group *** only di-and tri-substituted hydrosilanes,but also alkoxysilane is suitable,which does explore the scope of the family of 1-amino-2-silyl *** ligand relay phenomenon between neutral tridentate NNN ligand and anionic NNN ligand is observed for the first time via absorption spectral analysis in this one-pot,two-step *** primary mechanism has been proposed based on the control experiments.

关键词： Ligand relay catalysis Difunctionalization Styrene Alkoxysilane Hydroamination Diazo compounds

General Model of Temperature-dependent Modulus and Yield Strength of Thermoplastic Polymers

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Chinese Journal of Polymer Science 2020年第4期38卷 382-393,I0007页

作者： Ping-Yuan Huang zhan-sheng Guo Jie-Min Feng Shanghai Institute of Applied Mathematics and Mechanics School of Mechanics and Engineering ScienceShanghai UniversityShanghai200072China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai 200072China

A general model was developed to predict the temperature-dependent modulus and yield strength of different thermoplastic *** model,which depends on only two parameters with clear and specific physical meanings,can describe the temperaturedependent modulus and yield strength of thermoplastic polymers over the full glass transition *** temperature-dependent modulus and yield strength of three thermoplastic polymers were measured by uniaxial tension tests over a temperature range of 243-383 *** predictions showed excellent agreement with the experimental *** analysis of model input parameters showed negligible effect on the present general *** universality of the present general model was further validated,showing excellent agreement with published experimental data on other thermoplastic polymers and their composites.

关键词： Thermoplastics Modulus Yield strength Modeling Glass transition

Recent Advances in Enantioselective Reactions of Terminal Unactivated Alkenes

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Chinese Journal of Chemistry 2024年第7期42卷 760-776页

作者： Qihang Guo Xuzhong Shen zhan lu Centerof ChemistryforFrontier Technologies Departmentof ChemistryZhejiang UniversityHangzhouZhejiang 310058China ZJU-Hangzhou Global Scientific and Technological Innovation Center HangzhouZhejiang 311215China College of Chemistry Zhengzhou UniversityZhengzhouHenan 450001China

α-Olefins as aliphatic terminal alkenes could be obtained easily from numerous contemporary synthetic reactions as well as petro-chemical industry,and also found in natural *** to the alkenes attaching the directing groups or activating group,the catalytic asymmetric reaction of unactivated terminal alkenes presents great challenges due to the weak electron effect and small steric hindrance *** review mainly summarizes the latest progress of the asymmetric reaction of unactivated terminal olefins since 2016.

关键词： Asymmetric catalysis Terminal unactivated alkenes Hydrofunctionalization Difunctionalization Metal-catalyzed

An experimental investigation of one-and two-degree of freedom VIV of cylinders

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Acta Mechanica Sinica 2013年第2期29卷 284-293页

作者： Zhuang Kang lu-sheng Jia College of Shipbuilding Harbin Engineering University CNOOC Research Institute

In the paper,an experiment investigation was conducted for one-and two-degree of freedom vortex-induced vibration（VIV） of a horizontally-oriented cylinder with diameter of 11 cm and length of 120 *** the experiment,the spring constants in the cross-flow and in-line flow directions were regulated to change the natural vibration frequency of the model *** was found that,in the one-degree of freedom VIV experiment,a ＂double peak＂ phenomenon was observed in its amplitude within the range of the reduced velocities tested,moreover,a ＂2T＂ wake appeared in the vicinity of the second *** the two-degree of freedom VIV experiment,the trajectory of cylinder exhibited a reverse ＂C＂ shape,i.e.,a ＂new moon＂ *** analysis of these data,it appears that,besides the non-dimensional in-line and cross-flow natural vibration frequency ratios,the absolute value of the natural vibration frequency of cylinder is also one of the important parameters affecting its VIV behavior.

关键词： One- and two-degree of freedom VIV “2T” wake “New moon” trajectory Natural vibration frequency ratio

Monitoring nearest neighbor queries with cache strategies

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第4期8卷 529-537页

作者： PAN Peng lu Yan-sheng College of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China

The problem of continuously monitoring multiple K-nearest neighbor (K-NN) queries with dynamic object and query dataset is valuable for many location-based applications. A practical method is to partition the data space into grid cells, with both object and query table being indexed by this grid structure, while solving the problem by periodically joining cells of objects with queries having their influence regions intersecting the cells. In the worst case, all cells of objects will be accessed once. Object and query cache strategies are proposed to further reduce the I/O cost. With object cache strategy, queries remaining static in current processing cycle seldom need I/O cost, they can be returned quickly. The main I/O cost comes from moving queries, the query cache strategy is used to restrict their search-regions, which uses current results of queries in the main memory buffer. The queries can share not only the accessing of object pages, but also their influence regions. Theoretical analysis of the expected I/O cost is presented, with the I/O cost being about 40% that of the SEA-CNN method in the experiment results.

关键词： K-nearest neighbors (K-NNs) Continuous query Object cache Query cache

The interactions between bloodstream and vascular structure on aortic dissecting aneurysmal model: A numerical study

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Acta Mechanica Sinica 2013年第3期29卷 462-468页

作者： Zeng-sheng Chen zhan-Ming Fan Xi-Wen zhang Department of Engineering Mechanics School of AerospaceTsinghua University Institute of Heart Pulmonary & Vascular Diseases Capital University of Medical Science Affiliated Beijing Anzhen Hospital

Stent-graft implantation is an important means of clinical treatment for aortic dissecting aneurysm （ADA）. However, researches on fluid dynamics effects of stent were rare. Computer simulation was used to investigate the interactions between bloodstream and vascular structure in a stented ADA, which endures the periodic pulse velocity and pressure. We obtained and analyzed the flow velocity distribution, the wall displacement and wall stress in the ADA. By comparing the different results between a non-stented and a stented ADA, we found that the insertion of a vascular graft can make the location of maximum stress and displacement move from the aneurysm lumen wall to the artery wall, accompanied with a greatly decrease in value. These results imply that the placement of a stent-graft of any kind to oc-clude ADA will result in a decreased chance of rupture.

关键词： Aortic dissecting aneurysm (ADA) · Stent-graft · Fluid-structure interaction (FIS)

NO_x reduction by coupling combustion with recycling flue gas in iron ore sintering process

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International Journal of Minerals,Metallurgy and Materials 2011年第4期18卷 390-396页

作者： Yan-guang Chen zhan-cheng Guo Gen-sheng Feng School of Chemistry and Chemical Engineering No.beast Petroleum University Daqing 163318 China2 Key Laboratory of the Ministry of Education of China for Recycling ＆ Ecological Metallurgy University of Science and Technology Beijing Beijing 100083 China2

A new process called＇NOx reduction by coupling combustion with recycling flue gas（RCCRF）＇was proposed to decrease NOx emission during the iron ore sintering *** simulation test of NOx reduction was performed over sintered ore and in the process of coke ***,NOx reduction was also carried out by sintering pot *** sintered ore,the amount of NOx emission is reduced by 15wt%-25wt% at 400-550oC using 2.0vol% H2 or 2.0vol% CO,or reduced by 10wt%-30wt% at 560-720oC using 0.15vol% *** reduction is around 10wt% by coupling combustion of pyrolysis gas and coke,or around 16wt% by recycling flue gas into coke *** RCCRF,the maximum NOx reduction ratio is about 23wt% in coke combustion experiment and over 40wt% in sintering pot test.

关键词： nitrogen oxides combustion flue gases iron ores sintering

An Explicit Backlund Transformation of Burgers Equation with Applications

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Communications in Theoretical Physics 2005年第6X期44卷 987-989页

作者： lu Zhuo-sheng Key Laboratory of Mathematics Mechanization Academy of Mathematics and Systems Science the Chinese Academy of Sciences Beijing 100080 China

In this paper, an explicit Bgcklund transformation （BT） of the Burgers equation is obtained by using the further extended tanh method [Phys. Lett. A 307 （2003） 269; Chaos, Solitons ＆ Fractals 17 （2003） 669]. Based on the BT and some newly obtained seed solutions, infinite sequences of exact solutions for the Burgers equation are generated. Further more, this BT of the Burgers equation is applied to solve the variant Boussinesq equations and the approximate equations of long water wave.

关键词： Burgers equation Backlund transformation exact solution