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SNOEK-Kê-K■STER PEAK OF INTERNAL FRICTION IN Fe-P-N ALLOyS

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Acta Metallurgica Sinica(English Letters) 1998年第1期11卷 12-18页

作者： y.y.Che G.y.Zeng y.C.Xu J.W Ji Northeastern Univ Shenyang China

The internal friction and precipitate phases of the deformed Fe-P-N alloys have been investigated. It has been found that the ratio of depends on the content of P and the relation holds if the content of N is lower than *** and the content of P is lower than ***. It shows that the intercept K2 is related to the presence of the atomic pairs and clusters of P in the alloy matrix.

关键词： internal friction Fe-P-N alloy

A HOMOTOPy METHOD OF SWITCHING SOLUTION BRANCHES AT THE PITCHFORK BIFURCATION POINT

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Journal of Computational Mathematics 2001年第3期19卷 299-308页

作者： Cong, y.-H. Zhu, Z.-y. College of Mathematical Sciences Shanghai Teachers University Shanghai 200234 China

Provides information on a study which proposed a continuation method for switching solution branches at a pitchfork point. Problem of the standard pitchfork; Information on the systems of equations; Numerical examples... 详细信息

关键词： homotopy method switching solution branches pitchfork point

A new design of dual-constituent triangular lattice metamaterial with unbounded thermal expansion

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Acta Mechanica Sinica 2019年第3期35卷 507-517页

作者： y.C.Zhang y.J.Liang S.T.Liu y.D.Su State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian 116024China New Functional Structural Design and Verification Key Laboratory of Aeronautical Technology Shenyang 110035China

Triangular lattice metamaterials composed of bi-layer curved rib elements (called the Lehman-Lakes lattice) possess unbounded thermal expansion, high stiffness and impossibility of thermal buckling, which are highly desirable in many engineering structural applications subjected to large fluctuations in temperature. However, the requirement of such lattice metamaterial is that it must be a hinged joint in order to achieve the bending deformation upon heating freely, which directly leads to poor manufacturability, especially in small dimensions. In this study, a new design of dual-constituent triangular lattice metamaterial (DTLM) with good manufacturability is proposed to achieve the identical unbounded thermal expansion. In this lattice, a special bi-layer curved rib element where layer one is partially covered by layer two is presented, where the hinge joints are not necessary because the flexural rigidity in the single-layer part is much smaller than that in the bi-layer part, and the desirable thermal bending deformation can be achieved. A sample fabricated by additive manufacturing is given in order to show the good manufacturability;simultaneously, the multifunctional performance of the tailored DTLM with zero, large positive or negative coefficient of thermal expansion (CTE) can remain excellent, as well as the Lehman-Lakes lattice. Examples illustrate that the DTLM with zero CTE has about 34.2% improvement in stiffness and meanwhile has 17% reduction in weight compared with the Lehman-Lakes lattice. The stiffness of the DTLM has a moderate reduction when achieving the same large positive or negative CTE. In addition, the thermomechanical properties of the DTLM are given by the closed-form analytical solution and their effectiveness is verified by the detailed numerical simulation.

关键词： Metamaterial Zero thermal expansion Lattice material Multifunctional design Additive manufacturing

Effects of building aspect ratio,diurnal heating scenario,and wind speed on reactive pollutant dispersion in urban street canyons

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Journal of Environmental Sciences 2012年第12期24卷 2091-2103页

作者： Nelson y.O.Tong Dennis y.C.Leung Department of Mechanical Engineering The University of Hong Kong

A photochemistry coupled computational fluid dynamics （CFD） based numerical model has been developed to model the reactive pollutant dispersion within urban street canyons, particularly integrating the interrelationship among diurnal heating scenario （solar radiation affections in nighttime, daytime, and sun-rise/set）, wind speed, building aspect ratio （building-height-to-street-width）, and dispersion of reactive gases, specifically nitric oxide （NO）, nitrogen dioxide （NO2） and ozone （O3） such that a higher standard of air quality in metropolitan cities can be achieved. Validation has been done with both experimental and numerical results on flow and temperature fields in a street canyon with bottom heating, which justifies the accuracy of the current model. The model was applied to idealized street canyons of different aspect ratios from 0.5 to 8 with two different ambient wind speeds under different diurnal heating scenarios to estimate the influences of different aforementioned parameters on the chemical evolution of NO, NO2 and 03. Detailed analyses of vertical profiles of pollutant concentrations showed that different diurnal heating scenarios could substantially affect the reactive gases exchange between the street canyon and air aloft, followed by respective dispersion and reaction. Higher building aspect ratio and stronger ambient wind speed were revealed to be, in general, responsible for enhanced entrainment of 03 concentrations into the street canyons along windward walls under all diurnal heating scenarios. Comparatively, particular attention can be paid on the windward wall heating and nighttime uniform surface heating scenarios.

关键词： photochemistry reactive pollutant dispersion building aspect ratio diurnal heating scenario wind speed urban streetcanyon

PURIFICATION OF COBALT ANOLyTE USING THE NOVEL SOLVENT EXTRACTION SySTEM

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Acta Metallurgica Sinica(English Letters) 2003年第2期16卷 114-121页

作者： y.F.Shen W.y.Xue W.y.Niu Jinchuan Non-ferrous Metals Complex Jinchuan 737100ChinaState Key Laboratory of Rolling and AutomationNortheastern UniversityShenyang 110014ChinaState Key Laboratory of Rolling and AutomationNortheastern UniversityShenyang 110014ChinaState Key Laboratory of Rolling and AutomationNortheastern UniversityShenyang 110014China

In present research, a novel extractant system (D2EHPA + naphthenic acid + pyridine- ester) was used to purify cobalt anolyte and a simulated industrial production were carried out. This novel extraction system can extract Cu and/or Ni against Co from chloride medium solutions at pH range of 2.5-4.5. About 2g/l nickel and 0.2g/l copper were removed from the cobalt chloride anolyte containing about 100g/l cobalt and 200g/l chloride ions respectively, the raffinate contains nickel and copper less than 0.03g/l and 0.0003g/l respectively and can be used to electrolyze high-purity cobalt. About 5.5t cobalt anolyte was purified in the simulation industrial experiment and kilogram quantities of cobalt of 99.98% purity and about 95% recovery have been produced.

关键词： solvent extraction nickel cobalt anolyte naphthenic acid pyridine-ester

Effect of site amplification on inelastic seismic response

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Earthquake Engineering and Engineering Vibration 2019年第3期18卷 535-554页

作者： Adhikary S Singh y Department of Civil Engineering Visvesvaraya National Institute of Technology Nagpur-440010 Maharashtra India Department of Earthquake Engineering Indian Institute of Technology Roorkee-247667 Uttarakhand India

The available models for eff ective periods of site and structure are reviewed in context of frequency tuning in the inelastic seismic response of soil-structure system. The eff ect of seismic intensity and ductility demand, on the eff ective periods, is investigated, and inelastic site amplifi cation is shown to be strongly correlated to the normalized eff ective period. Two non-dimensional parameters, analogous to the conventional site amplifi cation factors in codes, are defi ned to quantify the inelastic site amplifi cation. It is shown that the inelastic site amplifi cation factor (i.e. ratio of constant ductility spectral ordinates at soil site to those at rock outcrop) is able to represent the site eff ects more clearly, as compared to the inelastic site amplifi cation ratio (i.e. ratio of inelastic spectral ordinates at soil site to the corresponding elastic spectral ordinates at rock outcrop). Further, the peak in the amplifi cation factor corresponding to the eff ective site period diminishes rapidly with increasing ductility demand.

关键词： site amplifi cation normalized response spectra eff ective period inelastic seismic response inelastic site amplifi cation factor

Interaction of Nicotine and Bovine Serum Albumin

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Chinese Chemical Letters 2000年第3期11卷 247-250页

作者： Wang, y Cheng, y Sun, HF Peking Univ Dept Tech Phys Div Appl Chem Beijing 100871 Peoples R China

The binding of nicotine to bovine serum albumin (BSA) was studied by UV absorption. fluorescence, and H-1 NMR methods. With the addition of nicotine, the absorption band of BSA at about 210 nm decreased gradually, moved to longer wavelengths, and narrowed. BSA fluorescence of tryptophan residue was quenched by nicotine. The H-1 NMR peaks of nicotine moved to downfield by the addition of BSA. The experimental results showed that nicotine was capable of binding with BSA to form a 1:1 complex. BSA's high selectivity for nicotine binding suggests a unique role for this protein in the detoxification and/or transport of nicotine.

关键词： nicotine BSA UV absorption fluorescence H-1 NMR

Mathematical modelling of axonal microtubule bundles under dynamic torsion

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Applied Mathematics and Mechanics(English Edition) 2018年第6期39卷 829-844页

作者： J.y.WU Hong yUAN L.y.LI MOE Key Laboratory of Disaster Forecast and Control in Engineering Institute of Applied MechanicsJinan University School of Engineering University of Plymouth

Owing to its viscoelastic nature, axon exhibits a stress rate-dependent me- chanical behavior. An extended tension-shear chain model with Kelvin-Voigt viscoelas- ticity is developed to illustrate the micromechanical behavior of the axon under dynamic torsional conditions. Theoretical closed-form expressions are derived to predict the de- formation, stress transfer, and failure mechanism between microtubule （MT） and tau protein while the axon is sheared dynamically. The results obtained from the present an- alytical solutions demonstrate how the MT-tau interface length, spacing between the tau proteins, and loading rate affect the mechanical properties of axon. Moreover, it is found that the MTs are more prone to rupture due to the contributions from the viscoelastic effects. Under the torsional force, the MTs are so long that the stress concentrates at the loaded end where axonal MTs will break. This MT-tau protein dynamics model can help to understand the underlying pathology and molecular mechanisms of axonal injury. Additionally, the emphasis of this paper is on the micromechanical behavior of axon, whereas this theoretical model can be equally applicable to other soft or hard tissues, owning the similar fibrous structure.

关键词： torsion biocomposite diffuse axonal injury (DAI) Kelvin-Voigt viscoelas-tic model dynamic response tension-shear chain model

A COMPREHENSIVE MODEL OF LASER CLADDING By POWDER FEEDING

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Acta Metallurgica Sinica(English Letters) 2004年第1期17卷 21-27页

作者： y.L.Huang G.y.Liang J.y.Su School of Materials Science and Engineering Xi'an Jiaotong University Xi'an 710049 ChinaSchool of Materials Science and Engineering Xi'an Jiaotong University Xi'an 710049 ChinaSchool of Materials Science and Engineering Xi'an Jiaotong University Xi'an 710049 China

A novel model was presented to predict the evolutionary development of cladding layer, and a method based on Lambert-Beer theorem and Mie's theory was adopted to treat the interaction between powder stream and laser beam. By using the continuum model and enthalpy-porosity method, the fluid flow and heat transfer in solid-liquid phase change system were simulated. The commercial software PHOENICS, to which several modules were appended, was used to accomplish the simulation. Numerical computation was performed for Stellite 6 cladding on steel, the obtained results are coincident with those measured in experiment basically.

关键词： laser cladding powder feeding cladding layer interaction