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Multiscale simulation of nanometric cutting of single crystal copper——effect of different cutting speeds

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Acta Metallurgica Sinica(English Letters) 2009年第6期22卷 440-446页

作者： Hongmin PEN Qingshun BAI yingchun LIANG Mingjun chen School of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China

A multiscale simulation has been performed to determine the effect of the cutting speed on the deformation mechanism and cutting forces in nanometric cutting of single crystal copper. The multiscale simulation model, which links the finite element method and the molecular dynamics method, captures the atomistic mechanisms during nanometric cutting from the free surface without the computational cost of full atomistic simulations. Simulation results show the material deformation mechanism of single crystal copper greatly changes when the cutting speed exceeds the material static propagation speed of plastic wave. At such a high cutting speed, the average magnitudes of tangential and normal forces increase rapidly. In addition, the variation of strain energy of work material atoms in different cutting speeds is investigated.

关键词： Multiscale simulation Nanometric cutting Single crystal copper Propagation speed of plastic wave

Aerodynamic Design Methodology for Blended Wing Body Transport

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Chinese Journal of Aeronautics 2012年第4期25卷 508-516页

作者： LI Peifeng ZHANG Binqian chen yingchun YUAN Changsheng LIN Yu College of Aeronautics Northwestern Polytechnical University Xi 'an 710072 China Shanghai Aircraft Design and Research lnstitute Commercial Aircraft Corporation of China Ltd. Shanghai200232 China

This paper puts forward a design idea for blended wing body（BWB）.The idea is described as that cruise point,maximum lift to drag point and pitch trim point are in the same flight *** to this design idea,design objectives and constraints are *** applying low and high fidelity aerodynamic analysis tools,BWB aerodynamic design methodology is established by the combination of optimization design and inverse design *** lift to drag ratio,pitch trim and acceptable buffet margin can be achieved by this design *** 300-passenger BWB configuration based on static stability design,as compared with initial configuration,the maximum lift to drag ratio and pitch trim are achieved at cruise condition,zero lift pitching moment is positive,and buffet characteristics is *** burn of 300-passenger BWB configuration is also significantly reduced as compared with conventional civil *** aerodynamic design is carried out under the constraints of BWB design requirements,the design configuration fulfills the demands for interior layout and provides a solid foundation for continuous work.

关键词： blended wing body aerodynamic configurations computational fluid dynamics optimization design inverse design

Enantioselective O-allylic alkylation of Morita-Baylis-Hillman carbonates with oxime

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Science China Chemistry 2009年第9期52卷 1309-1313页

作者： HU ZeKai CUI HaiLei JIANG Kun chen yingchun Key Laboratory of Drug-Targeting and Drug Delivery System of Education Ministry Department of Medicinal ChemistryWest China School of PharmacySichuan UniversityChengdu 610041China

The enantioselective O-allylic alkylation of acetophenone oxime with various Morita-Baylis-Hillman (MBH) carbonates has been accomplished by the catalysis of a commercially available cinchona alkaloid (DHQD)2PHAL. The... 详细信息

关键词： asymmetric organocatalysis allylic alkylation oxime Morita-Baylis-Hillman carbonates

Assessment on critical technologies for conceptual design of blended-wing-body civil aircraft

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Chinese Journal of Aeronautics 2019年第8期32卷 1797-1827,1794页

作者： Zhenli chen Minghui ZHANG yingchun chen Weimin SANG Zhaoguang TAN Dong LI Binqian ZHANG School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Shanghai Aircraft Design and Research Institute Commercial Aircraft Corporation of China LtdShanghai 201210China

Civil aviation faces great challenges because of its robust projected future growth and potential adverse environmental effects. The classical Tube-And-Wing(TAW) configuration following the Cayley’s design principles has been optimized to the architecture’s limit, which can hardly satisfy the further requirements on green aviation. By past decades’ investigations the BlendedWing-Body(BWB) concept has emerged as a potential solution, which can simultaneously fulfill metrics of noise, emission and fuel burn. The purpose of the present work is to analyze the developments of critical technologies for BWB conceptual design from a historical perspective of technology progress. It was found that the high aerodynamic efficiency of BWB aircraft can be well scaled by the mean aerodynamic chord and wetted aspect ratio, and should be realized with the trade-offs among stability and control and low-speed performance. The structure concepts of non-cylinder pressurized cabin are of high risks on weight prediction and weight penalty. A static stability criterion is recommended and further clear and adequate criteria are required by the evaluations of flying and handling qualities. The difficulties of propulsion and airframe integration are analyzed. The energy to revenue work ratios of well-developed BWB configurations are compared,which are 31.5% and 40% better than that of TAW, using state-of-art engine technology and future engine technology, respectively. Finally, further study aspects are advocated.

关键词： Aerodynamic design Bended-wing-body Propulsion Airframe Integration Stability and control Structure

Effect of vortex dynamics and instability characteristics on the induced drag of trailing vortices

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Chinese Journal of Aeronautics 2022年第9期35卷 160-173页

作者： Zepeng chenG Shiyan ZHANG Yang XIANG Chun SHAO Miao ZHANG Hong LIU yingchun chen School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Aircraft Design and Research Institute Commercial Aircraft Corporation of China Ltd.Shanghai 201210China

In this paper, trailing vortices generated by three wingtip configurations, namely the M6wing and the M6 wing with a blended or split winglet, are experimentally investigated using the Stereo Particle Image Velocimetry(SPIV) technology. Then, linear stability analysis is performed to investigate instability characteristics. Three corresponding trailing vortex patterns, including the isolated trailing vortex without wake(pattern v) and with wake(pattern v-w), co-rotating vortex pair(pattern v-v), are observed in experiments. The strength of trailing vortices, characterized by circulation, is reduced after installing winglets as expected, and the strength of pattern v-v can be further suppressed compared with pattern v-w. Moreover, instability characteristics, such as the eigenvalue spectrum and perturbation mode, are distinctive among these three vortex *** distribution of eigenvalue spectrums indicates that pattern v and pattern v-w are temporally“marginally stable”, while pattern v-v is temporally “unstable.” The primary perturbation mode of pattern v and pattern v-w is the m =-1 helical mode, while |m|>1 for the case of pattern *** effect of vortex dynamics and instability characteristics can be concluded in two ***, the value of induced drag is polluted by about 3% from vortex wandering since vortex wandering affects the tangential velocity and streamwise vorticity of trailing vortices. Secondly, the growth rate and penetration depth perturbation mode affect trailing vortex evolution and further affect induced drag. Specifically, the larger the growth rate and penetration depth are, the more turbulence injects inside the vortex core, thus leading to a quicker and more intense attenuation of trailing vortex, as well as a smaller induced drag. This finding can guide us to manipulate the induced drag in flow control.

关键词： Induced drag Linear stability analysis SPIV Trailing vortex Vortex flow Winglet

[3＋3] Formal Cycloadditions of Nitrones from Isatins and Azaoxyallyl Cations for Construction of Spirooxindoles

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Chinese Journal of Chemistry 2017年第6期35卷 857-860页

作者： Weijia Lin Gu Zhan Minglin Shi Wei Du yingchun chen Department of Medicinal Chemistry West China School of Pharmacy Sichuan University Chengdu Sichuan 610041 China College of Pharmacy Third Military Medical University Shapingba Chongqing 400038 China

A [3＋3] formal cycloaddition reaction between in situ formed azaoxyallyl cations and nitrones from isatins has been developed, furnishing a spectrum of spiro[1,2,4-oxadiazinan-5-one]oxindoles in good to excellent yields with excellent diastereoselectivity. This method provides direct and efficient access to potentially bioactive spirooxin- doles incorporating a six-membered heterocyclic scaffold.

关键词： cycloaddition spirooxindoles azaoxyallyl cations nitrones 1,3-dipoles

Multi-parameter Fault ProbabilityEvaluation Method of Large Generator

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高电压技术 2012年第8期38卷 1995-2000页

作者： HE yingchun WANG Youyuan chen Weigen State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing University Chongqing 400030 China

It is conducive to ensure the safety and reliability of the power system by means of timely and accurate evaluation of the reliability of large *** evaluation method of fault probability for large generators based on multi-characteristic parameters is proposed in this paper,which can be employed to solve the difficult problem of evaluating the occurrence probability of fault modes of large generators in the process of reliability ***,the set of fault characteristic parameters for a large generator is established on the basis of a large number of operation experiences and preventive test code for the large ***,according to the features of the fault characteristic parameters,two estimation methods of the fault mode occurrence probability are proposed,which are based on the fuzzy membership function and the relative deterioration degree,***,on the basis of the improved analytic hierarchy process(IAHP) method,the composite estimation method of the fault probability for a large generator is presented,which can reasonably and adequately use the information of various characteristic *** assessment case is provided to illustrate the specific process of this evaluation method and verify its effectiveness.

关键词：局部放电射频信号放电量高电压技术

Enantioselective direct aldol-type reaction of 4-hydroxycoumarin with ethyl trifluoropyruvate catalyzed by modified cinchona alkaloids

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Chinese Science Bulletin 2010年第17期55卷 1732-1734页

作者： CUI HaiLei JIANG Kun LIU YanKai Du Wei chen yingchun Key Laboratory of Drug-Targeting and Drug Deliver System of Ministrv of Education Department of Medicinal Chemistry West China School of Pharmacy Siehuan University Chengdu 610041 China

A new enantioselective aldol-type reaction of 4-hydroxycoumarins and ethyl trifluoropyruvate has been developed. In the presence of (DHQD)2PHAL (5 mol%), ethyl trifluoropyruvate could react with various 4-hydroxycoumarins to afford novel 4-hydroxycoumarin derivatives containing a tertiary trifluoromethyl alcohol center in good yields with moderate enantioselectivities.

关键词：对映选择性三氟甲基金鸡纳生物碱反应羟基改性催化乙基

Experimental investigation of self-oscillation feedback flow field structure and flow induced aeroacoustics for an open cavity in low speed wind tunnel

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Chinese Journal of Acoustics 2022年第4期41卷 358-372页

作者： LIANG Yong chen yingchun ZHAO Kun WANG Yong YUE Tingrui chen Zhengwu Low Speed Institute China Aerodynamics Research and Development CenterMianyang 621000 School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072 Commercial Aircraft Corporation of China Ltd.Shanghai 201200

To investigate the noise issue caused by open-cavity self-sustained oscillations,flow over a rectangular cavity with a length-to-depth ratio of 2 at Mach numbers of 0.10,0.15,0.20,and 0.25 was experimentally studied in a 0.55 m×0.40 m aeroacoustics wind ***,the velocity field and self-sustained oscillation were ***-frequency particle image velocimetry was employed to visualise the flow-field structure and analyse the path of the acoustic and pressure *** acoustic self-sustaining oscillation modes and duct modes were investigated by testing the far field and the fluctuating wall ***,the characteristics of the correlation between the wall pressure and the acoustic performance were *** results demonstrated that apart from the main vortex structure,shear vortices at the leading edge and crash vortices at the trailing edge were ***,around the frequencies of 875 Hz,1288 Hz,1875 Hz,and 2050 Hz,an evident tonal noise,induced by the cavity oscillation,could be *** addition,the wall pressure strongly correlated with the far-field noise,and the tone appeared at the same frequencies where the peaks occurred in the wall pressure spectra.

关键词： oscillation flow field