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Influences of substrate temperature on microstructure and corrosion behavior of APS Ni_(50)Ti_(25)Al_(25) inter-metallic coating

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Chinese Physics B 2018年第2期27卷 607-612页

作者： sh Khandanjou M Ghoranneviss sh Saviz M Reza Afshar Plasma Physics Research Center Science and Research Branch Islamic Azad University Department of Materials Engineering Science and Research Branch Islamic Azad University

In the present investigation, Ni_（50）Ti_（25）Al_（25）（at.%） mechanically alloyed powder is deposited on carbon steel *** the coating process, the substrate is heated to temperature ranging from room temperature to 400℃. The microstructure, porosity, microhardness, adhesion strength, and corrosion behavior of the coating are investigated at different substrate temperatures. Results show that coating porosity is lower on high temperature surface. Microhardness and adhesion strength of the deposition layer on the substrate without preheating have lower values than with preheating. The polarization test result shows that corrosion performance of the coating is dependent on micro cracks and porosities and the increasing of substrate temperature can improve the quality of coating and corrosion performance.

关键词： Ni50Ti25Al25 coating air plasma spray planetary ball milling inter-metallic compounds corrosion resistance

Solving two-dimensional Volterra-Fredholm integral equations of the second kind by using Bernstein polynomials

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Applied Mathematics(A Journal of Chinese Universities) 2017年第1期32卷 68-78页

作者： M.sh.Dahaghin sh.Eskandari Department of Mathematics Shahrekord University Shahrekord Iran

In this paper, we present a numerical method for solving two-dimensional VolterraFredholm integral equations of the second kind（2DV-FK2）. Our method is based on approximating unknown function with Bernstein polynomials. We obtain an error bound for this method and employ the method on some numerical tests to show the efficiency of the method.

关键词： Volterra approximating approximate variational proof iterative uniformly exact wavelet inequality

The future of retinal gene therapy: evolving from subretinal to intravitreal vector delivery

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Neural Regeneration Research 2021年第9期16卷 1751-1759页

作者： Maya Ross ron Ofri Koret School of Veterinary Medicine The Hebrew University of JerusalemRehovotIsrael

Inherited retinal degenerations are a leading and untreatbale cause of blindness, and as such they are targets for gene therapy. Numerous gene therapy treatments have progressed from laboratory research to clinical trails, and a pioneering gene therapy received the first ever FDA approval for treating patients. However, currently retinal gene therapy mostly involves subretinal injection of the therapeutic agent, which treats a limited area, entails retinal detachment and other potential complications, and requires general anesthesia with consequent risks, costs and prolonged recovery. Therefore there is great impetus to develop safer, less invasive and cheapter methods of gene delivery. A promising method is intravitreal injection, that does not cause retinal detachment, can lead to pan-retinal transduction and can be performed under local anesthesia in outpatient clinics. Intravitreally-injected vectors face several obstacles. First, the vector is diluted by the vitreous and has to overcome a long diffusion distance to the target cells. Second, the vector is exposed to the host's immune response, risking neutralization by pre-existing antibodies and triggering a stronger immune response to the injection. Third, the vector has to cross the inner limiting membrane which is both a physical and a biological barrier as it contains binding sites that could cause the vector's sequestration. Finally, in the target cell the vector is prone to proteasome degradation before delivering the transgene to the nucleus. Strategies to overcome these obstacles include modifications of the viral capsid, through rational design or directed evolution, which allow resistance to the immune system, enhancement of penetration through the inner limiting membrane or reduced degradation by intracellular proteasomes. Furthermore, physical and chemical manipulations of the inner limiting membrane and vitreous aim to improve vector penetration. Finally, compact non-viral vectors that can overcome

关键词： adeno-associated virus animal model blindness gene therapy inner limiting membrane photoreceptors retina retinitis pigmentosa vitreous

Ethnocultural heritage of the North-Eastern Caucasus as a factor of eco-tourism development

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Journal of Mountain Science 2024年第8期21卷 2810-2824页

作者： Zaburaeva Khava sh. Complex Research Institute named after Kh.I.Ibragimov of the Russian Academy of Sciences Grozny 366002Russia

The North-East Caucasus is a multi-ethnic mountain macroregion with a rich cultural heritage,insufficiently studied in the context of the ecotourism *** fill this gap and identify promising directions of environmentally safe forms of tourism,the author used in-depth review of modern literature to investigate the features of ecological tourism and the problems of preserving ethno-cultural heritage,and used historical and comparative-geographical methods to analyze the development of the tangible and intangible cultural heritage of the indigenous peoples of the North-Eastern Caucasus in different historical periods and to identify the geographical peculiarities of the distribution of historical and cultural monuments(tower buildings),pilgrimage sites and centers of traditional crafts and *** part of the planned expeditions,the author personally visited some historical monuments and handicraft centers for a deeper study of ethno-cultural *** cartographic method made it possible to visualize the *** results of the research show that the ethnocultural heritage of the North-East Caucasus is formed by material(historical and cultural monuments)and immaterial elements of culture(language,customs,traditions,ethnic identification)of those peoples,who live *** ethnocultural heritage is considered as the most important factor in the development of the tourism *** is revealed that this region has a large potential for development in various areas of *** highest concentration of religious buildings focused in mountainous *** tower structures were erected in mountainous and high-altitude *** ancient times to the present day there have been preserved various types of crafts and trades(pottery,metalworking,burka making,jewelry making,carpet weaving,gold embroidery,wood and stone carving,etc.),which can become objects of *** ethnocultural heritage of the North-East Caucasus needs to be preserved a

关键词： Mountainous districts Sustainable development Prospects Stone Towers Folk crafts

Launching jets from accretion belts

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Research in Astronomy and Astrophysics 2016年第5期16卷 1-6页

作者： ron Schreier Noam Soker Department of Physics Technion–Israel Institute of Technology

We propose that sub-Keplerian accretion belts around stars might launch jets. The sub-Keplerian inflow does not form a rotationally supported accretion disk, but it rather reaches the accreting object from a wide solid angle. The basic ingredients of the flow are a turbulent region where the accretion belt interacts with the accreting object via a shear layer, and two avoidance regions on the poles where the accretion rate is very low. A dynamo that is developed in the shear layer amplifies magnetic fields to high values. It is likely that the amplified magnetic fields form polar outflows from the avoidance regions. Our speculative belt-launched jets model has implications on a rich variety of astrophysical objects, from the removal of common envelopes to the explosion of core collapse supernovae by jittering jets.

关键词： stars: jets -- (stars:) binaries: accretion discs -- (stars:) supernovae: general -- accretion accretion disks

Improved Ligand-Field Theory with Effect of Electron-Phonon Interaction

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Communications in Theoretical Physics 2005年第3期43卷 529-538页

作者： MADong-Ping CHENJu-ron DepartmentofAppliedPhysics SichuanUniversityChengdu610065China／／InternationalCentreforMaterialsPhysicsAcademiaSinicaShenyang110015China DepartmentofAppliedPhysics SichuanUniversityChengdu610065China

Traditional ligand-field theory has to be improved by taking into account both 'pure electronic' contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved ligand-field theory, R1, R2, R'3, R'2, and R'1 lines, U band, ground-state zero-field-splitting (GSZFS), and ground-state g factors of ruby and/or GSGG: Cr3+ as well as thermal shifts of GSZFS, R1 line and R2 line of ruby have been *** results are in very good agreement with the experimental data. Moreover, it is found that the value of cubic-field parameter given by traditional ligand-field theory is inappropriately large. For thermal shifts of GSZFS, R1 line and R2 line of ruby, several conclusions have also been obtained.

关键词： improved ligand-field theory electron-phonon interaction Stokes shift energy spectrum thermal shift g factor

Regularized Principal Component Analysis

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Chinese Annals of Mathematics,Series B 2017年第1期38卷 1-12页

作者： Yonathan AFLALO ron KIMMEL Samsung Research Labs Ramat GanIsrael Computer Science Department TechnionIsrael Institute of TechnologyHaifaIsrael.

Given a set of signals, a classical construction of an optimal truncatable basis for optimally representing the signals, is the principal component analysis(PCA for short)approach. When the information about the signals one would like to represent is a more general property, like smoothness, a different basis should be considered. One example is the Fourier basis which is optimal for representation smooth functions sampled on regular grid. It is derived as the eigenfunctions of the circulant Laplacian operator. In this paper,based on the optimality of the eigenfunctions of the Laplace-Beltrami operator(LBO for short), the construction of PCA for geometric structures is regularized. By assuming smoothness of a given data, one could exploit the intrinsic geometric structure to regularize the construction of a basis by which the observed data is represented. The LBO can be decomposed to provide a representation space optimized for both internal structure and external observations. The proposed model takes the best from both the intrinsic and the extrinsic structures of the data and provides an optimal smooth representation of shapes and forms.

关键词： Laplace-Beltrami operator Principal component analysis Isometry

Two-dimensional analysis of a negative differential conductance gate transistor as a THz emitter

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Plasma Science and Technology 2017年第4期19卷 15-22页

作者： sh RAHMATALLAHPUR A ROSTAMI S KHORRAM Photonics and Nanocrystal Research Lab.(PNRL) Faculty of Electrical and Computer EngineeringUniversity of TabrizTabriz 51666-14761Iran Photonics Group Research Institute for Applied Physics and Astronomy(RIAPA)University of TabrizTabriz 51664-14761Iran

We investigate plasma modes in a transistor including a negative differential conductance in the gate. The analytical results show that the plasma wave generation is substantially influenced by the lateral direction （width of the transistor）, gate leakage current and ＇viscosity. The injection from the gate （opposed to the gate leakage current） can improve the plasma oscillations and their amplitude with respect to ordinary transistors. We also estimate, which to our best knowledge has been derived for the first time, the total power emitted by the transistor and the emitted pattern which qualitatively gives reasonable agreement with the experimental data. The results show that the radiated power depends on various parameters such as drift velocity, momentum relaxation time, gate leakage current and especially the lateral direction. A negative gate current enhances the power while the gate leakage current decreases the power.

关键词： terahertz emitter solid state plasma two-dimensional analysis negative differentialconductance

IMPORTANCE OF MOIST AMBIENT AND ITS HELICAL ENHANCEMENT EFFECT TO STORM INTENSITY

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Journal of Hydrodynamics 2004年第6期16卷 743-755页

作者： Al-FALAHI Fadha sh. Key Laboratory of Mesoscale Severe Weather Ministry of Education Department of Atmospheric Sciences Nanjing University Nanjing 210093 China

A crucial issue in evolution of severe storm, such as typhoon and even singlesupercell, is to diagnose and predict the sudden intensifying in storm. This paper describes anattempt to investigate the influence and effect of ambient moisture in the development of storm. Itwas mainly through a dynamic way to detect the helical enhancement by ambient moisture. It was foundthat the correlation between the ambient moistness and the intensity of rotating convective cellscan be well analyzed by helicity dynamics. The correlation between environmental streamwisevorticity (i. e. helicity) and vertical velocity (storm updraft or downdraft) is a powerfulindicator to catch favorable or unfavorable conditions for storm evolution. For this purpose, athree-dimensional non-hydrostatic storm-scale model, Advanced Regional Prediction System CARPS) wasemployed in order to numerically simulate a well-documented case of Del City supercell storm indifferent kinds of environmental moistness. Moreover, such different kinds of ambient moistenvironment and the resultant different morphologies and evolutions in the storm clearlydemonstrated that the abundant moistness in the environment that the storm embedded significantlystrengthens tbe storm intensity. In fact, the storm is embedded in much moist environment andtherefore larger instability propagates faster than the one in the drier air. It further producesstronger low-level mesocyclone with a much longer lifetime. The stronger convection and twist in theupdraft indicates that helical enhancement effect by moisture lead to stronger tornadic activity insevere storm.

关键词： moist ambient intensity of storm helical enhancement