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Computation of the stability derivatives via CFD and the sensitivity equations

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Acta Mechanica Sinica 2011年第2期27卷 179-188页

作者： Guo-dong Lei yu-Xin Ren Department of Engineering Mechanics Tsinghua University 100084 Beijing China

The method to calculate the aerodynamic stability derivates of aircrafts by using the sensitivity equations is ex- tended to flows with shock waves in this paper. Using the newly developed second-order cell-centered finite volume scheme on the unstructured-grid, the unsteady Euler equations and sensitivity equations are solved simultaneously in a non-inertial frame of reference, so that the aerodynamic stability derivatives can be calculated for aircrafts with complex geometries. Based on the numerical results, behavior of the aerodynamic sensitivity parameters near the shock wave is discussed. Furthermore, the stability derivatives are analyzed for supersonic and hypersonic flows. The numerical results of the stability derivatives are found in good agree- ment with theoretical results for supersonic flows, and variations of the aerodynamic force and moment predicted by the stability derivatives are very close to those obtained by CFD simulation for both supersonic and hypersonic flows.

关键词： Aerodynamic stability derivatives Non-inertial frame of reference unstructured-grid Finite volume scheme Sensitivity equations

Controllable Synthesis of CaCO_3 Micro/Nanocrystals with Different Morphologies in Microemulsion

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Chemical Research in Chinese Universities 2010年第5期26卷 678-682页

作者： yu dong CHU Ying dong Li-hong ZHUO yu-jiang Department of Chemistry Northeast Normal University Changchun 130024 P. R. China Elementary Normal College Dalian University Dalian 116300 P. R. China

Lens-like vaterite CaCO3 microrings composed of CaCO3 nanoparticles were synthesized via a microemulsion-mediated route at room temperature with ethanol and n-hexanol as co-surfactant. This process did not demand any additional energy such as heating or continuous agitation. It was the first time to use ethanol as co-surfactant in the synthesis of micro or nanomaterials. And the ethanol was believed to play an important role in the aggregation fashion of CaCO3 nanoparticles. Moreover, shuttle-shaped nanorods, hexagonal nanoplates, and rice-like nanoparticles were also fabricated by modulating the growth parameters. Additionally, the introduce of ethanol into microemulsions as co-surfactant may be generalized as a novel green route to control the structure of other functional materials.

关键词： CaCO3 Microring Cosurfactant

Electromagnetic Properties of S11 States in a Light Cone Quark Model

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Communications in Theoretical Physics 2006年第2X期46卷 269-274页

作者： HE Jun dong yu-Bing Institute of High Energy Physics the Chinese Academy of Sciences P.O. Box 918-4 Beijing 100049 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China

Using relativistic spin-flavor wave functions of a Lorentz-covariant light cone quark model, we calculate the electromagnetic form factors of two S11 resonances, N（1535） and N（1650）, and the helicity amplitudes A1/2 and S1/2 for electroexcitation of the S11 resonances from the nucleon. The electromagnetic form factors of these S11 resonances are found to be similar to those of the nucleon in shape, while the charge form factor of neutral N（1650） is nearly zero. The relative peak height of the S11 charge form factors is controlled by the mixing angle common to both resonance wave functions. As in most quark models, there is a systematic overestimate of A1/2 in both N（1535） and N（1650） cases at the photon point. A sizeable S1/2 for all cases is produced as suggested by experiments.

关键词： electromagntic properties S11 states light cone quark model

Effect of solution treatment on microstructure and mechanical properties of as-cast Al-12Si-4Cu-2Ni-0.8Mg-0.2Gd alloy

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China Foundry 2022年第3期19卷 238-244页

作者： yu-dong Sui Ye-hua Jiang Qu-dong Wang School of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China National Engineering Research Center of Light Alloys Net Forming and State Key Laboratory of Metal Matrix Composite Shanghai Jiao Tong UniversityShanghai 200240China

Effect of solution treatment on microstructure and mechanical properties of Al-12Si-4Cu-2Ni-0.8Mg-0.2Gd alloy was *** show the Si particles become stable and more intermetallic compounds dissolve in the matrix after solution treatment at 500℃for 2 h followed by 540℃for 3 h(T4).The skeleton-like Al_(3)CuNi develops into two parts in the T4 alloy:one is Al_(3)CuNi which has the framework shape;the other is intermetallics including the Al_(3)CuNi(size:5-10μm)and AlSiCuNiGd phases(size:≤5μm)with complex *** 0.2%Gd can improve the mechanical properties of the alloys after two-step solution treatment(500℃/2 h followed by 540℃/3 h),the hardness of the alloy increases from 130.9 HV to 135.8 HV compared with the alloy with one-step solution treatment(500℃/2 h),the engineering strength increases from 335.45 MPa to 352.03 MPa and the fracture engineering strain increases from 1.44%to 1.67%.

关键词： Al-Si-Cu-Ni-Mg alloy Gd element solution treatment microstructure mechanical properties

Characterization of intraocular pressure pattern and changes of retinal ganglion cells in DBA2J glaucoma mice

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International Journal of Ophthalmology(English edition) 2016年第2期9卷 211-217页

作者： Jing Wang yu dong Cullen Eye Institute Baylor College of Medicine

AIM： To characterize the pattern of intraocular pressure （lOP） change and the deficit of retinal ganglion cells （RGCs） in DBA2J, which is most well-characterized chronic glaucoma mouse model and wild type （WT） C57bl/6 mice, and to study the relationship between lOP change and RGCs deficit. METHODS： lOP was monitored with a rebound tonometer in C57bl/6 and DBA2J mice from 3 to 15-month-old. Retinal function was evaluated by dark -adapted electroretinogram （ERG） in DBA2J and WT mice of 15-month-old. A dye （Neurobiotin） was applied to optic nerve stump to retrograde label RGCs. TO-PRO-3 visualized all nuclei of cells in the RGC layer. RESULTS： The lOP in WT mice was 9.03-0.6 mm Hg on average and did not increase significantly as aging. The lOP in DBA2J mice, arranging from 7.2 to 28 mm Hg, was increasing significantly as aging, and it was normal at 3-month--old compared with WT mice, slightly increased from 7-month-old and increased in 50% animals at 11-month-old and in 38% animals at 15-month-old. The RGCs density in DBA2J mice started reducing by 7-month-old, continuously decreased until reached about 20% of RGC in WT retina by 15-month-old. RGC density was not linearly correlated with lOP in 15-month- old DBA2J mice. The amplitude of positive scotopic threshold response, and negative scotopic threshold response of ERG were significantly reduced in DBA2J mice of 15-month-old than that in age-paired WT mice. CONCLUSION： The present study found that DBA2J mice display pathological and functional deficits of the retina that was not linearly correlated with lOP.

关键词： retinal ganglion cell glaucoma intraocularpressure retina mouse

Flexible impedance sensor based on Ti_(3)C_(2)T_(x)MXene and graphitic carbon nitride nanohybrid for humidity-sensing application with ultrahigh response

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Rare Metals 2023年第7期42卷 2204-2213页

作者： Yang Lu Meng-yu Wang dong-yue Wang yue-Hang Sun Zi-Hao Liu Rong-Ke Gao Lian-dong yu dong-Zhi Zhang College of Control Science and Engineering China University of Petroleum(East China)Qingdao266580China

This paper reported the impedance-type humidity sensor based on Ti_(3)C_(2)T_(x)/g-C_(3)N_(4)nanomaterials which was fabricated on a flexible polyethylene terephthalate(PET)*** scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS)measurements were used to demonstrate the successful synthesis and combination of Ti_(3)C_(2)T_(x)and g-C_(3)N_(4)*** performance of the humidity sensor was tested at room *** experimental results showed that the Ti_(3)C_(2)T_(x)nanosheets with g-C_(3)N_(4)nanosheets endowed the humidity sensor with an ultra-high response,rapid response/recovery time,and negligible *** complex impedance spectroscopy(CIS)and bode diagrams were used to further analyze the sensing mechanism of the Ti_(3)C_(2)T_(x)/g-C_(3)N_(4)humidity *** Ti_(3)C_(2)T_(x)/g-C_(3)N_(4)humidity sensor can monitor skin humidity and high-humidity alarm,which demonstrates great potential applications in various fields.

关键词： Ti_(3)C_(2)T_(x)MXene Graphitic carbon nitride Flexible humidity sensor Humidity detection Alarm application

Additive manufacturing of mechanical testing samples based on virgin poly （lactic acid）（PLA） and PLA/wood fibre composites

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Advances in Manufacturing 2018年第1期6卷 71-82页

作者： yu dong Jamie Milentis Alokesh Pramanik Department of Mechanical Engineering Curtin UniversityGPO Box U1987 Perth WA 6845 Australia

3D printing in additive manufacturing is con-sidered as one of key technologies to the future high-pre-cision manufacturing in order to benefit diverse industriesin building construction, product development, biomedicalinnovation, etc. The increasing applications of 3D printedcomponents depend primarily on their significant merits ofreduced weight, minimum used materials, high precisionand shorter production time. Furthermore, it is very crucialthat such 3D printed components can maintain the same oreven better material performance and product quality asthose achieved by conventional manufacturing *** study successfully fabricated 3D printed mechanicaltesting samples of PLA and PLA/wood fibre composites.3D printing parameters including infill density, layer heightand the number of shells were investigated via design ofexperiments （DOE）, among which the number of shells wasdetermined as the most significant factor for maximisingtensile strengths of PLA samples. Further, DoE workevaluated the effect of material type （i.e., neat PLA andPLA/wood fibres） and the number of shells on tensile,flexural and impact strengths of material samples. It issuggested that material type is the only predominant factorfor maximising all mechanical strengths, which howeverare consistently lower for PLA/wood fibre compositeswhen compared with those of neat PLA. Increasing thenumber of shells, on the other hand, has been found toimprove almost all strength levels and decrease infillcavities.

关键词： Additive manufacturing (AM) Poly (lacticacid) (PLA) Wood fibres Polymer composites Designof experiments (DoEs)

Pion Cloud Effects on △-N Mass Splitting from Quark Models

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Communications in Theoretical Physics 2002年第8期38卷 189-194页

作者： dong yu-Bing FENG Qing-Guo Institute of High Energy Physics the Chinese Academy of Sciences P.O. Box 918-4 Beijing 100039 China Institute of High Energy Physics the Chinese Academy of Sciences P.O. Box 918-4 Beijing 100039 China

Pion cloud effects on △-N mass splitting are studied based on quark models. Pseudo-scalar pion-quarkcoupling is discussed in the relativistic and nonrelativistic frameworks. We separately calculate the pion cloud effects bythe one-pion exchange potential and by another method which is consistent with the baryon chiral perturbation *** able discrepancy in the mass splitting between the two methods is shown.

关键词： quark models, coupling constants, pion cloud, △-N mass splitting

Nucleon Form Factors and N-△ Transitions in a Hypercentral Constituent Quark Model with Meson Cloud

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Communications in Theoretical Physics 2007年第3期47卷 539-546页

作者： CHEN Dina-Yong dong yu-Bing Institute of High Energy Physics the Chinese Academy of Sciences Beijing 100049 China Gradtuate School of the Chinese Academy of Sciences Beijing 100049 China

We study the nucleon form factors and the nucleon-△（1232） transitions in a framework of hypercentral constituent quark model. The pion meson cloud effect is taken into account explicitly. Our results show that the pion cloud contributes substantially to the nucleon form factors as well as to the helicity amplitudes of △（1232）, and it gives an improved agreement compared to the experimental.

关键词： electromagnetic form factor nucleon and △(1232) hypercentral constituent quark model meson cloud