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Journal of Systems Science & Complexity 2018年第5期31卷 1146-1163页

作者： liu jun-jun The College of Mathematics Taiyuan University of Technology

This paper is concerned with the boundary feedback stabilization of a coupled ODE- Schrodinger system cascades with the external disturbance flowing the control end. The author uses the sliding mode control （SMC） to deal with the disturbance. By the SMC approach, the disturbance is supposed to be bounded only. The existence and uniqueness of the solution for the closed-loop via SMC are proved, and the monotonicity of the ＂reaching condition＂ is presented without the differentiation of the sliding mode function, for which it may not always exist for the weak solution of the dosed-loop system. Some numerical simulations is presented to illustrate the effectiveness of the proposed control.

关键词： Boundary control cascade systems disturbance rejection sliding mode control

Numerical Investigation of Three-dimensional Aeroacoustic Characteristics of Owl-inspired Trailing-edge Fringes

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Journal of Bionic Engineering 2023年第3期20卷 1103-1120页

作者： Jiaxin Rong hao liu Shanghai Jiao Tong University and Chiba University International Cooperative Research Center(SJTU-CU ICRC) Shanghai200240China Graduate School of Engineering Chiba University1-33Yayoi-choInage-kuChiba263-8522Japan

Owls are widely known for their silent flight,which is attributed to their unique wing morphologies comprising leading-edge(LE)serrations,trailing-edge(TE)fringes,and a velvety *** aeroacoustic characteristics of owl-inspired TE fringes have been widely investigated through two-dimensional(2D)modeling,but remain yet poorly studied in association with their three-dimensional(3D)***,we present a numerical study of the 3D aeroacoustic characteristics of owl-inspired TE fringes in which we combined large-eddy simulations(LES)with the Ffowcs Williams‒Hawkings *** constructed a clean wing model and three wing models with TE fringes that were distributed differently *** aerodynamic forces and 3D acoustic characteristics reveal that,like the 2D results of our previous studies,the 3D TE fringes enable remarkable sound reduction spatially while having aerodynamic performance comparable to the clean *** of the near-field 3D flow structures,vortex dynamics,and flow fluctuations show that TE fringes can robustly alter the 3D flow by breaking 3D TE vortices into small eddies and mitigating 3D flow ***,it is verified that TE fringes alter spanwise flows,thus dominating the 3D aeroacoustic characteristics in terms of passive flow control and flow stabilizations,whereas the fringes are inefficient in suppressing the acoustic sources induced by wingtip ***,the TE fringes distributed at midspan have better acoustic performance than those in the vicinity of the wingtip,indicating the importance of a spanwise distribution in enhancing aeroacoustic performance.

关键词： Owl Three-dimensional trailing-edge fringes Aeroacoustics Large-eddy simulation Ffowcs Williams‒Hawkings equation

Research on infrared dim and small target detection algorithm based on low-rank tensor recovery

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Journal of Systems Engineering and Electronics 2023年第4期34卷 861-872页

作者： liu Chuntong WANG hao College of Missile Engineering Rocket Force University of EngineeringXi’an 710025China Beijing Institute of Remote Sensing Equipment Beijing 100854China

In order to rapidly and accurately detect infrared small and dim targets in the infrared image of complex scene collected by virtual prototyping of space-based downward-looking multiband detection,an improved detection algorithm of infrared small and dim target is proposed in this ***,the original infrared images are changed into a new infrared patch tensor mode through data ***,the infrared small and dim target detection problems are converted to low-rank tensor recovery problems based on tensor nuclear norm in accordance with patch tensor characteristics,and inverse variance weighted entropy is defined for self-adaptive adjustment of ***,the low-rank tensor recovery problem with noise is solved by alternating the direction method to obtain the sparse target image,and the final small target is worked out by a simple partitioning *** test results in various spacebased downward-looking complex scenes show that such method can restrain complex background well by virtue of rapid arithmetic speed with high detection probability and low false alarm *** is a kind of infrared small and dim target detection method with good performance.

关键词： complex scene infrared block tensor tensor kernel norm low-rank tensor restoration weighted inverse entropy alternating direction method

Automatic recognition and intelligent analysis of central shrinkage defects of continuous casting billets based on deep learning

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Journal of Iron and Steel Research International 2023年第5期30卷 937-948页

作者： Gong-hao Lian Qi-hao Sun Xiao-ming liu Wei-miao Kong Ming Lv Jian-jun Qi Yong liu Ben-ming Yuan Qiang Wang Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina Shandong Iron and Steel Group Co. Ltd.Jinan 271105ShandongChina HBIS Material Technology Research Institude Shijiazhuang 050023HebeiChina Special Steel Business Department of Shandong Steel Laiwu Branch Jinan 271105ShandongChina

The internal quality inspection of the continuous casting billets is very important,and mis-inspection will seriously affect the subsequent production *** UNet-VGG16 transfer learning model was used for semantic segmentation of the central shrinkage defects of the continuous casting *** automatic recognition accuracy of the central shrinkage defects of the continuous casting billets reaches more than *** use the minimum circumscribed rectangle to quantify the geometric dimensions such as length,width and area of the central shrinkage defects and use the threshold method to rate the central shrinkage defects of the continuous casting *** results show that all the testing images are rated correctly,and this method achieves the automatic recognition and intelligent analysis of the central shrinkage defects of the continuous casting billets.

关键词： Central shrinkage Deep learning Image segmentation Circumscribed rectangle Automatic recognition

Investigation on UV-curing Reprocessable Thermosets Bearing Hindered Urea Bonds and Their Composites with Modified Zinc Oxide Nanoparticles

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Chinese Journal of Polymer Science 2024年第6期42卷 751-765页

作者： jun-hao Zhou Li-Ming Tang Key Laboratory of Advanced Materials of Ministry of Education of China Department of Chemical EngineeringTsinghua UniversityBeijing100084China

In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot *** prepolymers were characterized fully by various ***,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and *** from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical ***,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their *** influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then *** composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT *** addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.

关键词： Polyurethane-urea methacrylate Hindered urea bond ZnO nanoparticles Reprocessing UV curing

A data transmission scheduling algorithm for rapid-response earth-observing operations

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Chinese Journal of Aeronautics 2014年第2期27卷 349-364页

作者： Li jun Li jun Chen hao Jing Ning College of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China Unit 61726 PLA Wuhan 430074 China

With the development of rapid-response Earth-observing techniques, the demand for reducing a requirements-tasking-effects cycle from 1 day to hours grows rapidly. For instance, a satellite user always wants to receive requested data in near real-time to support their urgent mis- sions, such as dealing with wildfires, volcanoes, flooding events, etc. In this paper, we try to reduce data transmission time for achieving this goal. The new feature of a responsive satellite is that users can receive signals from it directly. Therefore, the traditional satellite control and operational tech- niques need to be improved to accommodate these changes in user needs and technical upgrading. With that in mind, a data transmission topological model is constructed. Based on this model, we can deal with the satellite data transmission problem as a multi-constraint and multi-objective path- scheduling problem. However, there are many optional data transmission paths for each target based on this model, and the shortest path is preferred. In addition, satellites represent scarce resources that must be carefully scheduled in order to satisfy as many consumer requests as possible. To efficiently balance response time and resource utilization, a K-shortest path genetic algorithm is proposed for solving the data transmission problem. Simulations and analysis show the feasibility and the adaptability of the proposed approach.

关键词： Data transmission in nearreal-time Genetic algorithm K-shortest path Operationally responsivespace Remote sensing Scheduling

Chiral phonon activated spin Seebeck effect in chiral materials

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 149-155页

作者： Xiao Li Jinxin Zhong Jinluo Cheng hao Chen Huiqian Wang jun liu Dali Sun Lifa Zhang jun Zhou Phonon Engineering Research Center of Jiangsu Province Center for Quantum Transport and Thermal Energy ScienceSchool of Physics and TechnologyNanjing Normal UniversityNanjing 210023China Center for Phononics and Thermal Energy Science China-EU Joint Lab for NanophononicsSchool of Physics Science and EngineeringTongji UniversityShanghai 200092China Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of ScienceChangchun 130033China Department of Mechanical and Aerospace Engineering North Carolina State UniversityRaleigh NC 27606USA Department of Physics North Carolina State UniversityRaleigh NC 27695USA Organic and Carbon Electronics Laboratories(ORaCEL) North Carolina State UniversityRaleigh NC 27606USA

Efficient generation of spin polarization is very important for spintronics and quantum computation. In chiral materials without magnetic order nor spin-orbit coupling, we find a new spin selectivity effect—chiral phonon activated spin Seebeck(CPASS)effect. Starting with the nonequilibrium distribution of chiral phonons under a temperature gradient, the CPASS coefficients are computed based on the Boltzmann transport theory. With both the phonon-drag and band transport contributions, the spin accumulations generated by the CPASS effect exhibit quadratic dependence on the temperature gradient. The strength of the CPASS effect and the relative magnitude of both contributions are tunable by the chemical potential modulation. The CPASS effect, which gives a promising explanation on the traditional chiral-induced spin selectivity effect, provides opportunities for the exploration of advanced spintronic devices based on chiral materials even in the absence of any magnetic order and spin-orbit coupling.

关键词： spin Seebeck effect chiral phonon phonon-drag contribution efficient spin generation

Definition and Classification of Low-Resistivity Oil Zones

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Journal of China University of Mining and Technology 2006年第2期16卷 228-232页

作者： liu Shuang-lian liu jun-lai LI hao ZHOU Yong-sheng State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China Key Laboratory of Lithosphere Tectonics and Lithoprobing Techology of Ministry of Education China University of Geosciences Beijing 100083 China Exploration and Production Research Institute SINOPEC Beijing 100083 China China University of Petroleum Beijing 102249 China Exploration and Production Research Institute PetroChina Beijing 100083 China

Although the analysis of the microcosmic mechanism for low-resistivity oil zones has received much attention in China, the intrinsic relationship between low-resistivity oil zones and geological background is still under-developed. Based on the geology and logging analysis, we redefine low-resistivity oil zones. According to their genesis, low-resis- tivity oil zones can be distinguished as five different classes: low-resistivity oil zones formed by tectonic settings, by depositional settings, by diagenetic settings, by invaded settings and those which are formed by the compounding geneses respectively. We make the following observations from this study on the definition and classification of low-resistivity oil zones: 1) A low-resistivity oil reservoir has macroscopic and microscopic unity. 2) The genesis of low-resistivity oil zones varies with the type of petroliferous basin. 3) Some low-resistivity oil zones can be forecasted based on the geological study results. 4) The results in this paper suggest that well logging information is generated from two cause mechanisms, the geophysical factors and the geological setting. Future studies on the geological background cause mechanism and the theory of well logging information will enrich the theory of logging geology and improve the ability to forecast oil zones.

关键词： low-resistivity oil zone geologic background genesis classification

Prospective life cycle assessment of CO_(2)conversion by photocatalytic reaction

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Green Chemical Engineering 2024年第3期5卷 383-389页

作者： jun-Qi Wang Xiang-jun liu Jing-Jing Ma Shuai Zhang hao-Ran liu Yong-Li Dong Qing-Yuan Yang School of Human Settlements and Civil Engineering Xi'an Jiaotong UniversityXi'an710049China School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'an710049China

CO_(2)conversion is gradually seen as a better way for society to effectively use carbon sources and avoid climate crisis associated with fossil CO_(2)*** the decision to deploy CO_(2)technology scale should be relied on its environmental *** this work,life cycle assessment model evaluates the environmental performance of CO_(2)conversion by photocatalytic reaction process with two different catalysts(NiAl-LDH and Co-ZIF-9).Six impact categories considered in this analysis,including climate change,acidification potential,depletion of abiotic resources,eutrophication potential,ozone layer depletion potential,and photochemical oxidation *** indicated that CO_(2)conversion with Co-ZIF-9 photocatalyst has a better environmental impact than the NiAl-LDH photocatalyst ***,the Co-ZIF-9 catalyst scenario also has a lower total environmental burden than the conventional CO production *** analysis shows that recycle performance of the catalyst is highly sensitive to the production process in two *** study could provide a framework for robust decisions in CO_(2)conversion by photocatalytic reaction,which is useful for policymakers to decide the feasibility of industrialization.

关键词： Life cycle assessment(LCA) CO_(2) Photocatalytic reaction Sensitivity analysis Uncertainty analysis

Recent advances in regulating the performance of acid oxygen reduction reaction on carbon-supported non-precious metal single atom catalysts

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Journal of Energy Chemistry 2023年第1期76卷 601-616,I0015页

作者： Yanqiu Wang Jiayu hao Yang liu Min liu Kuang Sheng Yue Wang jun Yang Jie Li Wenzhang Li School of Chemistry and Chemical Engineering Central South UniversityChangsha 410083HunanChina School of Physics and Electronics Central South UniversityChangsha 410083HunanChina

Developing high performance and low-cost catalysts for oxygen reduction reaction(ORR)in challenging acid condition is vital for proton-exchange-membrane fuel cells(PEMFCs).Carbon-supported nonprecious metal single atom catalysts(SACs)have been identified as potential catalysts in the *** advance has been obtained in constructing diverse active sites of SACs for improving the performance and understanding the fundamental principles of regulating acid ORR ***,the ORR performance of SACs is still ***,microenvironment adjustment of SACs offers chance to promote the performance of acid *** this review,acid ORR mechanism,attenuation mechanism and performance improvement strategies of SACs are *** strategies for promoting ORR activity of SACs include the adjustment of center metal and its *** relationship of ORR performance and structure is discussed with the help of advanced experimental investigations and theoretical calculations,which will offer helpful direction for designing advanced SACs for ORR.

关键词： Oxygen reduction reaction Single atom catalysts Microenvironment of center metal Regulation of center metal atoms Electron structure Proton-exchange-membrane fuel cells