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Fluid flow and fluid shear stress in canaliculi induced by external mechanical loading and blood pressure oscillation

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applied Mathematics and Mechanics(English Edition) 2015年第5期36卷 681-692页

作者： Shulun LIU Fan WANG Renhuai LIU institute of applied Mechanics Jinan University

The paper studies the problem of fluid flow and fluid shear stress in canaliculi when the osteon is subject to external mechanical loading and blood pressure *** single osteon is modeled as a saturated poroelastic cylinder. Solid skeleton is regarded as a poroelastic transversely isotropic material. To get near-realistic results, both the interstitial fluid and the solid matrix are regarded as compressible. Blood pressure oscillation in the Haverian canal is considered. Using the poroelasticity theory, an analytical solution of the pore fluid pressure is obtained. Assuming the fluid in canaliculi is incompressible, analytical solutions of fluid flow velocity and fluid shear stress with the Navier-Stokes equations of incompressible fluid are obtained. The effect of various parameters on the fluid flow velocity and fluid shear stress is studied.

关键词： incompressible oscillation cylinder Stokes isotropic interstitial Navier canal realistic saturated

Thermal Stability of ALD Lanthanum Aluminate Thin Films on Si(100)

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Journal of Materials Science & Technology 2014年第4期30卷 347-352页

作者： Xiaofeng She Hongtao Wang institute of applied Mechanics Zhejiang University

The thermal stability of high-K dielectrics on Si is critical in avoiding the malfunction of metal oxide field effect transistors （MOSFET） in devices. Series of annealing experiments have been performed to investigate the thermal stability of atomic layer deposited （ALD） lanthanum aluminate （LAO） thin films, a promising amorphous high-K candidate. The abrupt interface between LAO and Si remains intact at temperatures below 600 ℃. Above this temperature, a SiO2-rich interfacial layer begins to appear and thickens at higher temperatures. At 900 ℃, the interface is roughened due to the formation of nano sized crystal nuclei above the interfacial layer, which indicates the interfacial reactions with the Si substrate. The thermal stability of ALD AI203 thin films on Si have also been studied under similar conditions. The AI203/Si interface retains its smoothness even after full crystallization. This comparison suggests that the rare earth element may catalyze the interfacial reactions. Further annealing experiments on LAO films with different thickness end with a capping layer show that the oxygen source of the interfacial layer mainly comes from the ALD oxide films.

关键词： Thermal stability High-K dielectric Atomic layer deposition Lanthanum aluminate

A numerical analytic method for electromagnetic radiation accompanying with fracture of rocks

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Chinese Physics B 2010年第10期19卷 333-338页

作者：陈震黄卡玛 institute of applied Electromagnetics Sichuan University

This paper studies Rabinovitch＇s compression experiments on granite and chalk and proposes a.n oscillating dipole model to analyse and simulate the electromagnetic radiation phenomenon caused by fracture of rocks. Our model assumes that the electromagnetic radiation pulses are initiated by vibrations of the charged rock grains on the tips of the crack. The vibrations of the rock grains are stimulated by the pulses of the cracks. Our simulations show comparable results with Rabinovitch＇s compression experiments. From the simulation results, it verifies an assumption that the crack width is inversely proportional to the circular frequency electromagnetic radiation, which is presented by Rabinovitch et al. The simulation results also imply that, by using our oscillating dipole model together with Rabinovitch＇s two equations about the crack length and crack width, we can quantitatively analyse and simulate the electromagnetic radiation phenomenon, which is induced from the fracture of the rocks.

关键词： oscillating dipoles electromagnetic radiation model fracture of rocks

Bi-stable states of initially stressed elastic cylindrical shell structures with two piezoelectric surface layers

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Acta Mechanica Sinica 2015年第5期31卷 653-659页

作者： Bin Wang Guo-Hua Nie institute of applied Mechanics School of Aerospace Engineering and Applied MechanicsTongji University

A theoretical model is proposed in this paper to predict the bi-stable states of initially stressed cylindrical shell structures attached by surface anisotropic piezoelectric *** condition for existence of bi-stability of the shell structural system is presented and analytical expressions for corresponding rolled-up radii of the stable shell are given based on the principle of minimum strain *** resulting solution indicates that the shell system may have two stable configurations besides its initial state under a combined action of the actuating electric field and initial stresses characterized by the bending *** the piezoelectric layer materials act as only sensor materials without the actuating electric field,initial stresses may produce the bi-stable states,but one corresponding to its initial *** the shell without initial stresses,the magnitude in the actuating electric field determines the number of the stable states,one or two stable configurations besides the initial *** theoretical prediction for the bi-stable states is verified by finite element method（FEM） simulation by using the ABAQUS code.

关键词： Bi-stable Initial stress Cylindrical shell Piezoelectric layer Elastic potential energy Rolled-up radius Finite element

Ni/Y_2O_3-Al_2O_3 catalysts for hydrogen production from steam reforming of ethanol at low temperature

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Journal of Rare Earths 2012年第7期30卷 683-690页

作者：马洪波张荣斌黄思富谌伟庆石秋杰 institute of applied Chemistry Nanchang University

Y2O3-Al2O3 with different mole ratios of Y：Al were prepared by co-precipitation method. Catalysts Ni/Y2O3, Ni/Al2O3 and Ni/ Y2O3-Al2O3 were prepared by impregnation method. The result of BET showed that Al2O3 with relative high surface area was in favor of Ni distribution, whilst the TPR test demonstrated that composite support had appropriate synergistic effect between active constituent and sup-port, and NiO could be reduced more easily than loaded on the single support. H2-TPD test indicated that the catalyst NYA11 had lots of ac-tivity sites where H could be desorbed easily, which led to hydrogen-rich production over the catalyst. Composite support catalysts exhibited high activity for ethanol steam reforming （SRE）, and the supported catalyst with composite of 1：1 mole ratio of Y：Al exhibited the optimum catalytic properties for SRE. Ethanol could be completely converted over catalyst NYA11 even at 450 °C, and there had no inactivation after 60 h continuous reaction, hydrogen yield appeared maximum 35.9% at 400 ℃, and tended to increase with increasing H2O/EtOH molar ratio and feed flow rate.

关键词： Ni catalyst Y2O3-Al2O3 hydrogen production steam reforming of ethanol rare earths

Gain of harmonic generation in high gain free electron laser

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Chinese Physics C 2008年第4期32卷 297-302页

作者：邓海啸戴志敏 Shanghai institute of applied Physics CAS

In a planar undulator employed free electron laser （FEL）, each harmonic radiation starts from linear amplification and ends with nonlinear harmonic interactions of the lower nonlinear harmonics and the fundamental radiation. In this paper, we investigate the harmonic generation based on the dispersion relation driven from the coupled Maxwell-Vlasov equations, taking into account the effects due to energy spread, emittance, betatron oscillation of electron beam as well as diffraction guiding of the radiation field. A 3D universal scaling function for gain of the linear harmonic generation and a 1D universal scaling function for gain of the nonlinear harmonic generation are presented, which promise rapid computation in FEL design and optimization. The analytical approaches have been validated by 3D simulation results in large range.

关键词： harmonic FEL gain length

Bipartite entanglement in spin-1/2 Heisenberg model

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Chinese Physics C 2008年第4期32卷 303-307页

作者：胡明亮田东平 Department of applied Mathematics and applied Physics Xi'an Institute of Posts and Telecommunications

The bipartite entanglement of the two- and three-spin Heisenberg model was investigated by using the concept of negativity. It is found that for the ground-state entanglement of the two-spin model, the negativity always decreases as B increases if △ 〈γ- 1, and it may keep a steady value of 0.5 in the region of B 〈 J[（△＋ 1）2 -γ^2]^1/2 if △ 〉γ-1, while for that of the three-spin model, the negativity exhibits square wave structures if γ=0 or△=0. For thermal states, there are two areas showing entanglement, namely, the main region and the sub-region. The main region exists only when △ 〉 △c （△c =γ- 1 and （γ^2 - 1）/2 for the 2- and 3-spin model respectively） and extends in terms of B and T as A increases, while the sub-region survives only when γ≠0 and shrinks in terms of B and T as △ increases.

关键词： Heisenberg model bipartite entanglement negativity

Pitch models of Mandarin text-to-speech

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Journal of Harbin institute of Technology(New Series) 2009年第2期16卷 179-184页

作者：邵艳秋穗志方韩纪庆 institute of Computational linguistics Peking University School of Computer Science and Technology Harbin Institute of Technology

The function of prosody model will directly affect the naturalness of synthesized *** at the difficulty in generating the pitch contour in prosody model,two pitch models namely corpus-based pitch model and pitch pattern model are deeply studied in this *** problems in the corpus-based model are calculation of the distance and searching of the optimal path with dynamic programming *** the pitch pattern model,parameters such as pitch pattern,pitch average and pitch range are used to describe the pitch contour,and six pitch patterns are *** the generation of pitch contour,the pitch pattern model is more flexible than the corpus-based *** of the two models are linked to the real TTS system,and the MOS results of synthesized Mandarin speech show that the pitch pattern model is better than the corpus-based pitch model.

关键词： speech synthesis prosody model pitch model pitch pattern

Ignition Process Evolution at High Supersonic Velocities in Channel

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Journal of Thermal Science 2009年第2期18卷 166-172页

作者： M.A.Goldfeldl A.V.Starov K.Yu.Timofeev V.A.Vinogradov institute of Theoretical and applied Mechanics Central institute of Aviation Motors

The results of experimental research of multi-injector combustors in the regime of the attached pipe are *** a source of high-enthalpy working gas (air), hot shot wind tunnel IT-302M of ITAM, the Siberian Branch ofthe Russian Academy of Sciences was used. Tests have been carried out at Mach numbers 3,4 and 5, in a range ofchange of total temperature from 2000K up to 3000K and static pressure from 0.08MPa up to 0.23MPa. Injectorsection has been manufactured in two versions with a various relative height of wedge-shaped injectors with parallelfuel injection. Influence of conditions on the entrance of the combustion chamber on ignition and a stablecombustion of hydrogen was investigated. Intensive combustion of hydrogen has been received only at Machnumbers 3 and 4. Advantage of injector section with the greater relative height of injectors is revealed. Themechanism of fuel ignition in the combustion chamber of the given configuration was investigated: two-step ignitionprocess including 'kindling' and intensive combustion over all channel volume.

关键词： supersonic combustor ignition stable combustion.