Ultra-Wideband Five-Tier LM-mode Filters Optimized with knowledge-based CAD system

An original knowledge-based CAD system for step-by-step automated development offive-tier filters base don wave guide-dielectric resonators with the lowest LM-modes has been proposed. The basic idea of the system created consists in physical analysis of signals passing through the filter, which is performed on the basis of a known solution for electrodynamic problem of scattering of fundamental electromagnetic waves in a multi-tier structure. Regularities in formation of the filter ultra-wide bandwidths and formalized them in the form of production rules for the system were discovered. A comparative analysis of frequency responses for three- and five-tier UWB filters, optimized with the system has been also provided. The designed filters are intended for the next generation of millimeter waveband wireless systems and conform to the latest standards like ECMA-387, WirelessHD, IEEE 802.15.3c and IEEE 802.11ad.Предложена оригинальная САПР последовательного проектирования пятизвенных фильтров на основе волноводно-диэлектрических резонаторов с низшими LM-модами. Ключевая идея разработанной системы заключается в физическом анализе сигнала прошедшего через фильтр, который рассчитывается на основе известного решения электродинамической задачи рассеяния основной волны на многозвенной структуре. Установлены закономерности формирования ультрашироких полос пропускания фильтров, которые формализованы в виде логических продукций. Проведен сравнительный анализ АЧХ трех- и пятизвенных ультрашироких фильтров, сконструированных системой. Параметры фильтров отвечают новому поколению радиотелекоммуникационных систем миллиметрового диапазона соответствующих новейшим стандартам ECMA-387, WirelessHD, IEEE 802.15.3candIEEE 802.11ad

Intellectual CAD of mm waves WDR filters with increased stop band attenuation

Physical principles of the original intellectual CAD development for three-tier WDR filters with increased stop band attenuation are presented in the article. The electrodynamic parameters of the partly filled resonators with quasi-H101 and quasi- H102 eigenmodes, which influencing on their frequency separation are analysed. The results of filters designing, proper to the recent standards ECMA-387, WirelessHD, IEEE 802.15.3c, IEEE 802.11ad, are presentedУ статті викладено фізичні принципи розробки оригінальної інтелектуальної САПР триланкових ХДР-фільтрів з розширеною областю позасмугового затухання. Проаналізовано електродинамічні параметри частково заповнених резонаторів з квазі- H101 - і квазі H102 модами, які впливають на їх взаємну частотну відстань. Результати конструювання фільтрів відповідають новітнім стандартам ECMA-387, WirelessHD, IEEE 802.15.3c, IEEE 802.11a

AdS/CFT correspondence via R-current correlation functions revisited

Motivated by realizing open/closed string duality in the work by Gopakumar [Phys. Rev. D70:025009,2004], we study two and three-point correlation functions of R-current vector fields in N=4 super Yang-Mills theory. These correlation functions in free field limit can be derived from the worldline formalism and written as heat kernel integrals in the position space. We show that reparametrizing these integrals converts them to the expected AdS supergravity results which are known in terms of bulk to boundary propagator. We expect that this reparametrization corresponds to transforming open string moduli parameterization to the closed string ones.Comment: 23 pages, v2: calculations clarified, references added, v3: sections re-arranged with more explanations, 4 figures and an appendix adde

A Device for Surface Study of Confined Micron Thin Films in a Total Internal Reflection Geometry

A device to probe the molecular structure of materials next to a solid interface in a thin film geometry has been developed. The device can produce controlled thicknesses as small as 1 mum with parallelity better than 0.003degrees. We have shown that the thickness and the parallelity of the film produced between two optical surfaces can be quantified using white light and monochromatic light interferometry, respectively. In addition, this apparatus allows the study of these films in a static state or under shear using spectroscopic techniques involving transmission or reflection measurements. (C) 2002 American Institute of Physics

Energy States of Colored Particle in a Chromomagnetic Field

The unitary transformation, which diagonalizes squared Dirac equation in a constant chromomagnetic field is found. Applying this transformation, we find the eigenfunctions of diagonalized Hamiltonian, that describe the states with definite value of energy and call them energy states. It is pointed out that, the energy states are determined by the color interaction term of the particle with the background chromofield and this term is responsible for the splitting of the energy spectrum. We construct supercharge operators for the diagonal Hamiltonian, that ensure the superpartner property of the energy states.Comment: 25 pages, some calculation details have been removed, typos correcte

The indisputable value of ultrasound diagnostics in acute small bowel obstruction

The use of ultrasound in the diagnosis of acute small bowel obstruction is justified from a tactical point of view, since it is not delayed in time, does not weigh down the patient's condition, has sufficient information and does not carry radiation load. Due to its safety and ease of use, this technique can be used repeatedly in the process of conservative treatment to determine further treatment tactics

A review on applications of Cu2ZnSnS4 as alternative counter electrodes in dye-sensitized solar cells

This is the final version. Available from AIP Publishing via the DOI in this record. A contribution of counter electrode (CE) emphasis a great impact towards enhancement of a dye-sensitized solar cell's (DSSC) performance and Pt based CE sets a significant benchmark in this field. Owing to cost effective noble metal, less abundance and industrial large scale application purpose, an effective replacement for Pt is highly demanded. There are several approaches to improve the performance of a CE for enhancing the power conversion efficiency with a less costly and facile device. To address this issue, reasonable efforts execute to find out suitable replacement of Pt is becoming a challenge by keeping the same electrochemical properties of Pt in a cheaper and eco-friendlier manner. With this, cheaper element based quaternary chalcogenide, Cu2ZnSnS4 (CZTS) becomes a prominent alternative to Pt and used as a successful CE in DSSC also. This review presents brief discussion about the basic properties of CZTS including its synthesis strategy, physicochemical properties and morphology execution and ultimate application as an alternative Pt free CE for a low cost based enhanced DSSC device. It is therefore, imperative for engineering of CZTS material and optimization of the fabrication method for the improvement of DSSC performance.Research Council of Norwa

Experimental studies of thorium ions implantation from pulse laser plasma into thin silicon oxide layers

We report the results of experimental studies related to implantation of thorium ions into thin silicon dioxide by pulsed plasma fluxes expansion. Thorium ions were generated by laser ablation from a metal target, and the ionic component of the laser plasma was accelerated in an electric field created by the potential difference (5, 10 and 15 kV) between the ablated target and SiO2/Si(001) sample. Laser ablation system installed inside the vacuum chamber of the electron spectrometer was equipped with YAG:Nd3+ laser having the pulse energy of 100 mJ and time duration of 15 ns in the Q-switched regime. Depth profile of thorium atoms implanted into the 10 nm thick subsurface areas together with their chemical state as well as the band gap of the modified silicon oxide at different conditions of implantation processes were studied by means of X-ray photoelectron spectroscopy (XPS) and Reflected Electron Energy Loss Spectroscopy (REELS) methods. Analysis of chemical composition showed that the modified silicon oxide film contains complex thorium silicates. Depending on local concentration of thorium atoms, the experimentally established band gaps were located in the range of 6.0 - 9.0 eV. Theoretical studies of optical properties of the SiO2 and ThO2 crystalline systems have been performed by ab initio calculations within hybrid functional. Optical properties of the SiO2/ThO2 composite were interpreted on the basis of Bruggeman effective medium approximation. A quantitative assessment of the yield of isomeric nuclei in "hot" laser plasma at the early stages of expansion has been performed. The estimates made with experimental results demonstrated that the laser implantation of thorium ions into the SiO2 matrix can be useful for further research of low-lying isomeric transitions in 229Th isotope with energy of 7.8(0.5) eV