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Large eddy simulation of boundary layer combustion of hydrogen and hydrocarbon fuel films in a modeled scramjet combustor

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Chinese Journal of Aeronautics 2024年第7期37卷 109-133页

作者： Jianfei WEI Silong ZHANG Jingying ZUO Xin LI Jiang QIN Wen BAO School of Energy science and Engineering Harbin Institute of TechnologyHarbin 150001China

Supersonic fuel film cooling is a promising way to simultaneously reduce the severe wall heat and friction load of the internal passage in a scramjet engine when operating at hypersonic *** eddy simulations were performed to investigate the cooling and wall friction characteristics of hydrogen and hydrocarbon films under inert and reactive *** results show that the essential difference of the turbulent state in the mixing layer contributes to the totally different behaviors of the cooling and wall friction reduction performances of the two fuel *** turbulent transport processes between the hydrogen film and the mainstream are much weaker as compared to the case of hydrocarbon film,making inert hydrogen rather superior in cooling and friction reduction ***,the increase of wall temperature for hydrogen film under the inert case is mainly driven by the loss of hydrogen with high heat capacity instead of by direct heat ***,the film cooling performance severely deteriorates when the hydrogen film burns due to presence of severe heat release sources near the *** the other hand,combustion of hydrocarbon film in the boundary layer can remarkably improve its originally barely-satisfactory cooling and friction reduction performance to the level comparable to that of hydrogen film,due to the suppression of turbulent transport processes in the mixing layer and presence of heat absorption sources near the ***,the hydrogen film is more advantageous in friction reduction,while the hydrocarbon film is more suitable for cooling.

关键词： Supersonic film cooling Hydrogen Hydrocarbon Boundary layer combustion Large eddy simulation

Experimental and numerical study of hypervelocity impact damage on composite overwrapped pressure vessels

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Defence technology（防务技术） 2024年第1期31卷 58-72页

作者： Yong-Pan Duan Run-Qiang Chi Bao-Jun Pang Yuan Cai Hypervelocity Impact Research Center Harbin Institute of TechnologyHarbin150080China College of science Heilongjiang University of Science and TechnologyHarbin 150022China

Ground-based tests are important for studying hypervelocity impact(HVI)damage to spacecraft pressure vessels in the orbital debris *** analyzed the damage to composite overwrapped pressure vessels(COPVs)in the HVI tests and classified the damage into non-catastrophic damage and catastrophic *** proposed a numerical simulation method to further study non-catastrophic damage and revealed the characteristics and mechanisms of non-catastrophic damage affected by impact conditions and internal *** fragments of the catastrophically damaged COPVs were collected after the *** crack distribution and propagation process of the catastrophic ruptures of the COPVs were *** findings contribute to understanding the damage characteristics and mechanisms of COPVs by HVIs.

关键词： Orbital debris Hypervelocity impact Composite overwrapped pressure vessels Damage mechanisms

Amphipathic Janus Nanofibers Aerogel for Efficient Solar Steam Generation

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Energy & Environmental Materials 2024年第4期7卷 422-432页

作者： Rui Wang Jinshuo Deng Ping Wu Qianli Ma Xiangting Dong Wensheng Yu Guixia Liu Jinxian Wang Lei Liu Chongqing Research institute Changchun University of Science and Technology Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province Changchun University of Science and Technology

Solar steam generation is a promising water purification technology due to its low-cost and environmentally friendly applications in water purification and ***,hydrophilic or hydrophobic materials alone are insufficient in achieving necessary characteristics for constructing highquality solar steam generators with good comprehensive properties.

关键词： aerogels electrospinning photothermal materials solar desalination solar steam generation

Fast fixed-time three-dimensional terminal guidance with non-concave trajectory constraint

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Chinese Journal of Aeronautics 2024年第3期37卷 208-218页

作者： Youmin GONG Yanning GUO Yueyong LYU Dongyu LI Guangfu MA Department of Control science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Cyber science and technology Beihang UniversityBeijing 100191China

Focusing on the non-concave trajectory constraint,a sliding-mode-based nonsingular feedback fast fixed-time three-dimensional terminal guidance of rotor unmanned aerial vehicle landing,planetary landing and spacecraft rendezvous and docking terminal phase with external disturbance is investigated in this ***,a fixed-time observer based on real-time differentiator is developed to compensate for the external disturbance,whose estimation error can converge to zero after a time independent of the initial ***,a sliding surface ensuring fixed-time convergence is *** sliding surface can guarantee that the vehicle achieves a non-concave trajectory,which is better for avoiding collision and maintaining the visibility of the landing site or docking ***,the nonsingular guidance ensuring the fixed-time convergence of the sliding surface is proposed,which is continuous and chatter *** last,three numerical simulations of Mars landing are performed to validate the effectiveness and correctness of the designed scheme.

关键词： Three-dimensional Terminal guidance Non-concave trajectory constraint Fast fixed-time control Sliding mode control

Selective core-shell doping enabling high performance 4.6 V-LiCoO2

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Journal of Energy Chemistry 2024年第8期95卷 684-693页

作者： Yueming Xia Jianrui Feng Jinhui Li Yan Li Zhengfeng Zhang Xiaoqi Wang Jianli Shao Manling Sui Pengfei Yan Beijing Key Laboratory of Microstructure and Property of Solids College of Materials Science & Engineering Beijing University of Technology Petro China Research institute of Petroleum Exploration & Development State Key Laboratory of Explosion science and technology Beijing Institute of Technology

Constructing robust surface and bulk structure is the prerequisite for realizing high performance high voltage LiCoO2（LCO）.Herein,we manage to synthesize a surface Mg-doping and bulk Al-doping coreshell structured LCO,which demonstrates excellent cycling ***-cell shows 94.2% capacity retention after 100 cycles at 3.0-4.6 V（***/Li+） cycling,and no capacity decay after 300 cycles for fullcell test（3.0-4.55 V）.Based on comprehensive microanalysis and theoretical calculations,the degradation mechanisms and doping effects are systematically *** the undoped LCO,high voltage cycling induces severe interfacial and bulk degradations,where cracks,stripe defects,fatigue H2 phase,and spinel phase are identified in grain *** the doped LCO,Mg-doped surface shell can suppress the interfacial degradations,which not only stabilizes the surface structure by forming a thin rock-salt layer but also significantly improves the electronic conductivity,thus enabling superior rate *** Al-doping can suppress the lattice "breathing" effect and the detrimental H3 to H1-3 phase transition,which minimizes the internal strain and defects growth,maintaining the layered structure after prolonged *** theoretical calculations,this work deepens our understanding of the doping effects of Mg and Al,which is valuable in guiding the future material design of high voltage LCO.

关键词： Doping effect Electron microscopy Failure mechanism High-voltage LiCoO2 Lithium-ion battery

Hybrid concurrency control protocol for data sharing among heterogeneous blockchains

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Frontiers of Computer science 2024年第3期18卷 1-12页

作者： Tiezheng GUO Zhiwei ZHANG Ye YUAN Xiaochun YANG Guoren WANG School of Computer science and technology Beijing Institute of TechnologyBeijing 100029China School of Computer science and Engineering Northeastern UniversityShenyang 110167China

With the development of information technology and cloud computing,data sharing has become an important part of scientific *** traditional data sharing,data is stored on a third-party storage platform,which causes the owner to lose control of the *** a result,there are issues of intentional data leakage and tampering by third parties,and the private information contained in the data may lead to more significant ***,data is frequently maintained on multiple storage platforms,posing significant hurdles in terms of enlisting multiple parties to engage in data sharing while maintaining *** this work,we propose a new architecture for applying blockchains to data sharing and achieve efficient and reliable data sharing among heterogeneous *** design a new data sharing transaction mechanism based on the system architecture to protect the security of the raw data and the processing *** also design and implement a hybrid concurrency control protocol to overcome issues caused by the large differences in blockchain performance in our system and to improve the success rate of data sharing *** took Ethereum and Hyperledger Fabric as examples to conduct crossblockchain data sharing *** results show that our system achieves data sharing across heterogeneous blockchains with reasonable performance and has high scalability.

关键词： data sharing blockchain concurrency control protocol crosschain

A self-powered solar-blind UV-enhanced Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si heterojunction photodetector for full spectral photoresponse and imaging

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Nano Research 2024年第4期17卷 2960-2970页

作者： Yajie Han Shujie Jiao Jiangcheng Jing Lei Chen Ping Rong Shuai Ren Dongbo Wang Shiyong Gao Jinzhong Wang School of Materials science and Engineering Harbin Institute of TechnologyHarbin 150001China

Self-powered full-spectrum photodetectors(PDs)offer numerous advantages,such as broad application fields,high precision,efficiency,and multi-functionality,which represent a highly promising and potentially valuable class of detectors for future ***,insensitive response to solar-blind ultraviolet(UV)and complex and expensive preparation processes greatly limit their performance and practical *** this study,a self-powered full-spectrum Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si heterojunction PD with high sensitivity for solar-blind UV band prepared by a simple and low-cost two-step synthesis method is *** results reveal that the developed PD has an excellent performance,such as high sensitivity from 200 to 850 nm,and a responsivity of 1.38 mA/W as well as a detectivity of 3.22×10^(10) Jones under 254 nm light at zero ***,the unencapsulated device displays exceptional stability and imaging *** is expected that Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si heterojunction PD with a simple and low-cost synthesis method has great potential for self-powered full-spectrum photodetectors.

关键词： Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si self-powered photodetector full spectral photoresponse imaging

Effects of Number of Bleed Holes on Shock-Wave/Boundary-Layer Interactions in a Transonic Compressor Stator

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Journal of Thermal science 2024年第2期33卷 611-624页

作者： LI Bai ZHOU Xun LUO Lei DU Wei School of Energy science and Engineering Harbin Institute of TechnologyHarbin150001China

An extensive numerical investigation is conducted to characterize the flow separation control in a transonic compressor cascade with a porous *** bleed holes are arranged on the suction surface in a single row,two staggered rows and three staggered *** each bleed scheme,five bleed pressure ratios are examined at an inlet Mach number of *** results indicate that the aerodynamic performance of the cascade is significantly improved by the porous *** the single-row scheme,the maximum reduction in total pressure losses is 57%.For the two-staggered-row and three-staggered-row schemes,there is an optimal bleed pressure ratio of 1.0,and the maximum reductions in total pressure loss are 68% and 75%,*** low loss in the cascade is due to the well-controlled boundary *** new local supersonic region created by the bleed hole is the key reason for the improved boundary *** vortex induced by side bleeding provides another mechanism for delaying flow *** the bleed holes could create multiple local supersonic regions,which reduce the range of the adverse pressure gradient that the boundary layer needs to *** is the reason why cascades with more bleed holes perform better.

关键词： transonic compressor stator shock wave/boundary layer interaction porous bleed number of bleed holes

Texture and Se vacancy optimization induces high thermoelectric performance in Bi_(2)Se_(3) flexible thin films

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Rare Metals 2024年第6期43卷 2796-2804页

作者： Dong-Wei Ao Wei-Di Liu Yue-Xing Chen Fan Ma Yi-Jie Gu Zhuang-Hao Zheng School of Machinery and Automation Weifang UniversityWeifang 261061China Australian institute for Bioengineering and Nanotechnology The University of QueenslandBrisbane 4072Australia Shenzhen Key Laboratory of Advanced Thin Films and Applications Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen518060China School of Materials science and Engineering Inner Mongolia University of TechnologyHohhot 010051China

Bi_(2)Se_(3)-based flexible thin film with high thermoelectric performance is promising for the waste heat recovery *** this work,a novel post-selenization method is employed to prepare n-type Bi_(2)Se_(3)flexible thin films with highly textured *** strengthened texture and Se vacancy optimization can be simultaneously achieved by optimizing the selenization *** highly oriented texture leads to the increased carrier mobility and results in a high electric conductivity of~290.47 S·cm^(-1)at 623 ***,a high Seebeck coefficient(>110μW·K-1)is obtained due to the reduced carrier concentration,induced by optimizing vacancy ***,a high power factor of 3.49μW·cm^(-1)·K^(-2)at 623 K has been achieved in asprepared highly-bendable Bi_(2)Se_(3)flexible thin films selenized at 783 *** study introduces an effective post-selenization method to tune the texture structure and vacancies of Bi_(2)Se_(3)flexible thin films,and correspondingly achieves high thermoelectric performance.

关键词： Thermoelectric Bi_(2)Se_(3) Flexible thin film Post-selenization