ةـصلاخلا : يوتحت لا و ةضفخنملا ةقاطلا تاذ تادحولا نم ديدعلا ىلع ةيكلسلالا تارعشتسملا ةكبش ةلصوب ةدوزم سلا ةيكل ثيح ، اهنيب اميف لاصتلال إ نكمي تارعشتسملا كلت ن دختسا ا اهم تا قيبطتلا نم د يدعلا يف . م ت د قو ا هتبقارم دار ملا ة قطنملا ى لع يئاوشع لكشب تارعشتسملا عيزوت ثحبلا اذه يف ا م لكش ب اهميس قت و إ ى ل ةدحاو لآ يوتحت ثيح ،ةقرفتم تانايب دعاوقآ لمعتل تاعومجم ة يناكم تا نايب ى لع تارعش تسمل...

In the present work, a single-crystalline epitaxial nonpolar a-plane AlN film with in-plane two-folder symmetries was successfully achieved on an r-plane sapphire substrate, by combining physical vapor deposition and high-temperature annealing technique. Moreover, varying thickness, evolution of crystalline quality structure were systematically investigated using X-ray diffraction, Raman spectr...

A detailed analysis of anomalies of metallic gratings is performed for a large interval of groove depths. Two types of zero of the zeroth diffraction order are distinguished: the Bragg type [Alta Freq. 38, 82 (1969)], exhibited in a Littrow mount for both TM and TE polarizations and localized for flat surfaces at negative imaginary infinity in the complex a plane of the sinus of angles of incid...

This article deals with the free in-plane vibration analysis of a frame with four arbitrary inclined members by differential transform method. Based on four differential equations and sixteen boundary and compatibility conditions, the related structural eigenvalue problem will be analytically formulated. The frequency parameters and mode shapes of the frame will be calculated for various values...

An approximation technique is considered for computing transmission and reflection coefficients for propagation of an elastic pulse through a planar slab of finite width. The propagation of elastic pulse through a planar slab is derived from first principles using straightforward time-dependent method. The paper ends with calculations of enhancement factor for the elastic plane wave and it is s...

In this paper we propose a new approach to plane partitioning with similar features to those of Polar Diagram, but we assume that the pole is close to the sites. The result is a new tessellation of the plane in regions called Near Pole Polar Diagram NPPD. Here we define the (NPPD) of points, the dual and the Contracted dual of it, present an optimal algorithms to draw them and discuss the appli...

a lot of research and various techniques have been devoted for finding the topologicaldescriptor wiener index, but most of them deal with only particular cases. there exist threeregular plane tessellations, composed of the same kind of regular polygons namely triangular,square, and hexagonal. using edge congestion-sum problem, we devise a method to computethe wiener index and demonstrate this m...

this paper has focused on vibration and buckling of thin rectangular plates when at least two opposite sides are simply supported condition and subjected to axial and biaxial initially stresses. analysis is based on exact solution method, without further usage of any approximate method. first analytic techniques are used to discuss the free vibrations of plate. then, natural frequencies and cri...