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High-fidelity simulation of blade vortex interaction of helicopter rotor based upon TENO scheme

Chinese Journal of Aeronautics 2023年第10期36卷 275-292页

作者： Wei BIAN Guoqing zhao Xi CHEN bo WANG Qijun zhao National Key Laboratory of Rotorcraft Aeromechanics College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

Numerical simulation methods for unsteady vortex field of helicopter rotor with high resolution and low dissipation TENO8-AA primitive variables reconstruction schemes are established based on moving-embedded grid and Navier-Stokes ***,the Targeted Essentially Non-Oscillatory(TENO)scheme are developed by employing ENO-like candidate stencil selection strategy,and the candidate stencil is adopted with optimal weight in smooth region while it is discarded completely in discontinuous region,which reduces the dissipation and dispersion errors and approaches better spectral ***,the aerodynamic characteristics of Helishape-7A model rotor in Blade Vortex Interaction(BVI)state and the flowfield of Lynx rotor in hover are simulated,which validates that the blade tip vortex trajectory with larger wake age and more details of vortex can be captured by TENO8-AA scheme with only a quarter of grid points and half time comparing to WENO-JS ***,the simulation accuracy of thrust coefficient is improved by up to 36%.Finally,the analyses for BVI and aeroacoustic characteristics of Operational Loads Survey(OLS)rotor are conducted,and the different forms of interaction mechanism are explored,such as oblique and parallel *** results indicate that TENO scheme not only ensures the resolution of simulation in discontinuous region,but also minimizes the numerical dissipation in smooth region dominated by blade tip ***,the acoustic pressure peak prediction error of rotor in BVI state is significantly reduced to 5.6%and 0.8%at two microphone locations,respectively.

关键词： Aeroacoustics Blade tip vortex Blade vortex interaction Helicopter rotor TENO scheme

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AN IMPROVED ERROR ANALYSIS FOR FINITE ELEMENT APPROXIMATION OF BIOLUMINESCENCE TOMOGRAPHY

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Journal of Computational Mathematics 2008年第3期26卷 297-309页

作者： Wei gong Ruo Li Ningning Yan Weibo zhao Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China CAPT LMAM and School of Mathematical Sciences Peking University Beijing 100871 China LSEC Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China School of Mathematical Sciences Peking University Beijing 100871 China

This paper is concerned with an ill-posed problem which results from the area of molecular imaging and is known as BLT problem. Using Tikhonov regularization technique, a quadratic optimization problem can be formulated. We provide an improved error estimate for the finite element approximation of the regularized optimization problem. Some numerical examples are presented to demonstrate our theoretical results.

关键词： BLT problem Tikhonov regularization Optimization problem A priori error estimate

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Direct constructions and proofs for CCA secure(LR)IBE with dual system encryption

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Science China(Information Sciences) 2017年第11期60卷 306-308页

作者： Yi zhao bo YANG School of Computer Science Shaanxi Normal University State Key Laboratory of Information Security Institute of Information EngineeringChinese Academy of Sciences

Dear editor,In the past decade,the development of identitybased cryptography has been highly *** to its superiority in the task of key distribution as well as its expressive ability,many related techniques have been made industrial *** and boyen[1]developed the first secure construction(BB1)in the standard model under a weakened adaptive notion called selective-ID *** then,ongoing research has contributed to enhancing the performance of IBE schemes in the standard model.

关键词： IBE CCA Direct constructions and proofs for CCA secure

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Oxidation behaviour of electron beam physical vapour deposition β-NiAlHf coatings at 1100℃ in dry and humid atmospheres

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Rare Metals 2016年第7期35卷 513-519页

作者： Kai Yan Hong-bo Guo Hui Peng Sheng-Kai gong School of Materials Science and Engineering Beihang University Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology Beihang University

NiA1 intermetallic compounds attract increas- ing attention for high-temperature applications due to their combination of excellent properties, especially as metallic protective coatings on superalloys or as bond coats in thermal barrier coatings （TBCs）. Oxidation behaviour of the β-NiA1Hf coatings prepared by electron beam physical vapour deposition （EB-PVD） was investigated at 1100 ℃ for short time and 100h in 20% 02＋Ar and 15 % H20 ＋ Ar, respectively. The results of mass changes re- veal that the addition of minor reactive element Hf sig- nificantly improves the cyclic oxidation resistance of the 13- NiA1 coatings in both dry and humid atmospheres. During the initial oxidation stage, water vapour retards the phase transformation from 0-A1203 to a-A1203. Moreover, com- pared with the case in dry atmosphere, water vapour sig- nificantly reduces the surface roughness of the oxide scales formed on EB-PVD β-NiA1Hf coatings after 100 h cyclic oxidation, which corresponds with the difference of surface morphologies of the oxide scales.

关键词： β-NiA1Hf coatings Water vapour Oxidation Phase transformation Roughness

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Influence factors on natural frequencies of composite materials

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Frontiers of Mechanical Engineering 2020年第4期15卷 571-584页

作者： bo WANG Feng zhao Zixu zhao Kunpeng XU School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Key Laboratory of Vibration and Control of Aero-Propulsion Systems(Ministry of Education) Northeastern UniversityShenyang 110819China

Compared with traditional materials, composite materials have lower specific gravity, larger specific strength, larger specific modulus, and better designability structure and structural performance. However, the variability of structural properties hinders the control and prediction of the performance of composite materials. In this work, the Rayleigh–Ritz and orthogonal polynomial methods were used to derive the dynamic equations of composite materials and obtain the natural frequency expressions on the basis of the constitutive model of laminated composite materials. The correctness of the analytical model was verified by modal hammering and frequency sweep tests. On the basis of the established theoretical model, the influencing factors, including layers, thickness, and fiber angles, on the natural frequencies of laminated composites were analyzed. Furthermore, the coupling effects of layers, fiber angle, and lay-up sequence on the natural frequencies of composites were studied. Research results indicated that the proposed method could accurately and effectively analyze the influence of single and multiple factors on the natural frequencies of composite materials. Hence, this work provides a theoretical basis for preparing composite materials with different natural frequencies and meeting the requirements of different working conditions.

关键词： composite material hammering and frequency sweep test structural parameter natural frequency

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Effect of aluminum on secondary recrystallization texture and magnetic properties of grain-oriented silicon steel

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Journal of Iron and Steel Research International 2021年第4期28卷 479-487页

作者： Qian Gao Xian-hui Wang Jun Li Jian gong bo Li Central Iron and Steel Research Institute Beijing 100081China Shougang Zhixin Qian'an Electromagnetic Material Co. Ltd.Qian'an 064404HebeiChina

The slab low-temperature reheating grain-oriented silicon steel was prepared in the laboratory,and the high-temperature annealing interruption tests were carried *** effects of aluminum(which meant acid-soluble aluminum)on the grain size texture,precipitate,magnetic properties and their correlations were *** results showed that with the increase in aluminum element,the grain size decreased,while the intensity of{114}and{111}textures increased in the primary recrystallization ***,the pinning force during the secondary recrystallization and the onset secondary recrystallization temperature were *** precipitates were concluded to have a more important role on determining the onset secondary recrystallization temperature than the primary grain *** higher onset temperature resulted in sharper Goss texture and the better magnetic properties,but when the aluminum content came up to a certain extent,a fine-grain structure was *** most suitable aluminum content for present study was 0.025 wt.%,while the onset secondary recrystallization temperature and the primary texture were considered to be conducive to the sharpness of Goss texture.

关键词： Grain-oriented silicon steel Aluminum Texture Secondary recrystallization Precipitate Magnetic property

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Synthesis and Properties of Hydroxytelechelic Polyisobutylenes by End Capping with tert-Butyl-dimethyl-(4-methyl-pent-4-enyloxy)-silane

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Chinese Journal of Polymer Science 2019年第9期37卷 936-942页

作者： Jing Li Kang-Da Wu Huang Shan Jing-Han Zhang Ming zhao Guang-Bi gong Wen-Li Guo Yi-bo Wu College of Materials Science & Engineering Beijing Institute of Petrochemical Technology Beijing 102617 China Lanzhou Petrochemical Research Center Petrochina Lanzhou 730060 China Beijing Key Laboratory of Specialty Elastomer Composite Materials Beijing Institute of Petrochemical Technology Beijing 102617 China

The low-activity cationic monomer tert-butyl-dimethyl-(4-methyl-pent-4-enyloxy)-silane was synthesized by Grignard reaction and hydroxyl-protection reaction. Living polyisobutylene chains were initially synthesized by controlled cationic polymerization and then capped with tert-butyl-dimethyl-(4-methyl-pent-4-enyloxy)-silane. The hydrolysis of these polyisobutylenes end capped with tert-butyl-dimethyl-(4-methyl-pent-4-enyloxy)-silane gave rise to hydroxytelechelic polyisobutylene. NMR analysis confirmed that the hydrolysis was complete. Results also showed that a low polymerization temperature favored the participation of tert-butyl-dimethyl-(4- methyl-pent-4?enyloxy)-silane in the end-capping reaction. Moreover, polyisobutylene-based polyurethane exhibited greater acid resistance than commercial polyurethane.

关键词： Carbocationic polymerization Polyisobutylene Hydrolysis Polyisobutylene-based polyurethane

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Ground State and Its Topological Properties of Three-Dimensional Spin-Orbit Coupled Degenerate Fermi Gases

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Chinese Physics Letters 2023年第12期40卷 143-148页

作者： Long Xiong Ming gong zhao-Xiang Fang Rui Sun International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China Key Lab of Quantum Information of Chinese Academy of Sciences School of PhysicsUniversity of Science and Technology of ChinaHefei 230026China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China School of Physical Science and Technology Xinjiang UniversityUrumqi 830046China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China

Three-dimensional(3D)degenerate Fermi gases in the presence of spin-orbit coupling,inducing various kinds of physical findings and phenomena,have attracted tremendous attention in these *** investigate the 3D spin-orbit coupled degenerate Fermi gases in theory and first present the analytic expression of their ground *** study provides an innovative perspective into understanding of the topological properties of 3D unconventional superconductors,and describes the topological phase transitions in trivial and topological phase ***,such a system is provided with a richer set of Cooper pairings than traditional *** dual Cooper pairs with same spin directions emerge and exhibit peculiar behaviors,leading to topological phase *** study and discussion can be generalized to some other types of unconventional superconductors and areas of optical lattices.

关键词： Fermi topological degenerate

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Understanding Self-assembly,Colloidal Behavior and Rheological Properties of Graphene Derivatives for High-performance Supercapacitor Fabrication

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Chinese Journal of Polymer Science 2020年第5期38卷 423-434,I0005页

作者： Xia-Wei Yun bo Tang Zhi-Yuan Xiong Xiao-gong Wang Department of Chemical Engineering Laboratory of Advanced Materials(Ministry of Education)Tsinghua UniversityBeijing 100084China Department of Chemical and Bio-molecular Engineering The University of MelbourneMelbourneVictoria 3010Australia

Graphene derivatives,such as graphene oxide(GO)and reduced graphene oxide(RGO),have been widely used as promising two-dimensional nanoscale building blocks due to their fascinating properties,cost-effective production,and good *** the intrinsic self-assembling,colloidal,and rheological features of graphene derivatives is of critical importance to establish the formation-structure-property relationship of graphene-based *** article reviews recent progresses in our studies of these interesting properties of graphene derivatives for developing high performance *** content is organized to include characteristics of the dispersions of graphene derivatives,self-assembly of nanosheets from liquid medium,colloidal behavior,rheological properties of the dispersions,processing methods based on the properties,and performance of the fabricated *** and RGO nanosheets are proved to form different types of assembled structures with unique morphologies,such as ultrathin layer-by-layer films,porous aggregates,and *** unique rheological properties of GO dispersions and hydrogels,feasible for both the traditional wet-processing and newly-developed technology like three-dimensional printing,are highlighted for their potential in structural manipulation and scalable fabrication of graphene-based *** research devoted to up-grading the performance of supercapacitors is presented in some details,which could be applicable for fabricating other graphene-based energy storage *** challenges and perspectives in our point of view are given in the last part of this feature article.

关键词： Graphene derivatives Self-assembly Colloids Rheology Processing Supercapacitor

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Theoretical analysis and experimental study of an air inflated membrane structure

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第1期11卷 25-33页

作者： Jing-hai gong Xiu-ying YANG Zi-zhao ZHANG Jin-cheng zhao Department of Civil Engineering Shanghai Jiao Tong University Sharighai 200240 China

In this paper,an experimental study of an air inflated membrane was carried out based on the China National Stadium (the Bird's Nest). After the 2008 Olympic Games,it was apparent that the future use of the Bird's Nest would be enhanced if rainfall could be prevented from entering the stadium. The installation of an air inflated membrane across the opening of the steel structure was proposed as a solution to this problem. To verify the scheme,a theoretical analysis and experimental study of an air inflated membrane was carried out. Experimental and computational models were developed,form-finding was carried out using both experimental and theoretical methods,and the results from the two approaches,including the deflection of the air inflated membrane and deformation of the support structure,were analyzed and compared. The force-transfer path and deformation of the air inflated membrane under loads was studied. Conclusions and suggestions are presented.

关键词： China National Stadium Air inflated membrane Form-finding

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