Microwave Electrodynamics of the Antiferromagnetic Superconductor GdBa_2Cu_3O_{7-\delta}

The temperature dependence of the microwave surface impedance and conductivity are used to study the pairing symmetry and properties of cuprate superconductors. However, the superconducting properties can be hidden by the effects of paramagnetism and antiferromagnetic long-range order in the cuprates. To address this issue we have investigated the microwave electrodynamics of GdBa_2Cu_3O_{7-\delta}, a rare-earth cuprate superconductor which shows long-range ordered antiferromagnetism below T_N=2.2 K, the Neel temperature of the Gd ion subsystem. We measured the temperature dependence of the surface resistance and surface reactance of c-axis oriented epitaxial thin films at 10.4, 14.7 and 17.9 GHz with the parallel plate resonator technique down to 1.4 K. Both the resistance and the reactance data show an unusual upturn at low temperature and the resistance presents a strong peak around T_N mainly due to change in magnetic permeability.Comment: M2S-HTCS-VI Conference Paper, 2 pages, 2 eps figures, using Elsevier style espcrc2.st

Appliacation of the Kalman filter in control systems of power electronics

Kalman filter can deal with measurement and modelling inaccuracies and, also, can be used for the join state estimation.Higher accuracy of the parameters estimation of a control object can increase the power efficiency of control systems in inverter-fed drives. This paper introduces the improved extended Kalman Filter (EKF) for the real-time speed estimation of an induction motor (IM) in the sensorless control system of inverter-fed drive.Key words: power electronics, inverter-fed drive, extended Kalman Filter, sensorless vectorcontrol system, microcontroller

Summary of pre-2008 Machine Induced Background Estimates for the LHCb Experiment

This document summarizes the pre-2008 estimates of particle flux arriving at the LHCb experiment from machine (LHC) related background sources. These particles arrive in the form of showers from both beam-gas interactions in the dispersion suppression and long straight section of IR8 and from proton losses on the IR8 tertiary collimators due to betatron cleaning inefficiencies, momentum cleaning inefficiencies and elastic beam-gas interactions along the LHC beam orbit

Noncontact electrical metrology of Cu/low-k interconnect for semiconductor production wafers

We have demonstrated a technique capable of in-line measurement of dielectric constant of low-k interconnect films on patterned wafers utilizing a test key of ~50x50 \mu m in size. The test key consists of a low-k film backed by a Cu grid with >50% metal pattern density and <250 nm pitch, which is fully compatible with the existing dual-damascene interconnect manufacturing processes. The technique is based on a near-field scanned microwave probe and is noncontact, noninvasive, and requires no electrical contact to or grounding of the wafer under test. It yields <0.3% precision and 2% accuracy for the film dielectric constant

A near-field scanned microwave probe for spatially localized electrical metrology

We have developed a near-field scanned microwave probe with a sampling volume of approximately 10 micron in diameter, which is the smallest one achieved in near-field microwave microscopy. This volume is defined to confine close to 100 percent of the probe net sampling reactive energy, thus making the response virtually independent on the sample properties outside of this region. The probe is formed by a 4 GHz balanced stripline resonator with a few-micron tip size. It provides non-contact, non-invasive measurement and is uniquely suited for spatially localized electrical metrology applications, e.g. on semiconductor production wafers.Comment: 6 pages, 3 figures, submitted to Appl. Phys. Let

Estimation and analysis of the machine-induced background at the TOTEM roman pot detectors in the IR5 of the LHC

The problem of background generation in the experimental insertion IR5 of the LHC during machine operation in the dedicated TOTEM mode with low intensity beams and the specially designed β* = 1540 m optics is discussed. The sources of the machine-induced background in the IR5 forward physics areas are identified and their relative importance is evaluated. The results of the background simulation in the IR5 are presented, based on the most recent estimates of the residual gas density for TOTEM beam conditions. The methods for background analysis and rejection are explained

Naturalizing consciousness emergence for ai implementation purposes: A guide to multilayered management systems

© 2017, IGI Global. All rights reserved. The purpose of this chapter is to delineate a naturalistic approach to consciousness. This bioinspired method does not try to emulate into a 1:1 scale real mechanisms but instead of it, we capture some basic brain mechanisms prone to be implemented into computational frameworks. Consequently, we adopt afunctional view on consciousness, considering consciousness as one among other cognitive mechanisms useful for survival purposes in natural environments. Specifically, we wish to capture those mechanisms related to decision-making processes employed by brains in order to produce adaptive answer to the environment, because this is the main reason for the emergence and purpose of consciousness

Химико-технологические аспекты повышения функциональных характеристик сегнетожесткой пьезокерамики

Objectives. Ferroelectrically hard piezoelectric ceramics are in demand for high-power applications in piezotransformers, ultrasonic emitters, and piezo motors, which requires a combination of high piezoelectric characteristics and mechanical quality factors in it. The aim of this research was to reveal the main regularities in the microstructure and functional characteristic formation of ferroelectrically hard piezoceramics based on two widespread chemical systems, Pb(ZrxTi1-x)O3 and (Na1-xKx)NbO3, through various technological modes of production. In this study, two fundamentally different technological ways of forming a dense microstructure on the example of above systems have been employed to obtain the best set of dielectric, piezoelectric, and mechanical parameters for practical applications. In the case of lead-containing ceramics, various sintering technologies have been used, including conventional ceramic, hot pressing, and spark plasma sintering.Methods. The microstructure of the piezoelectric ceramics was investigated using electron microscopy, and the functional characteristics were assessed in terms of mechanical and piezoelectric properties. The density values were determined by hydrostatic weighing in octane, the relative dielectric permittivity was measured using an LCR meter, and the values of the piezoelectric coefficient and mechanical quality factor were gathered using the resonance–antiresonance method.Results. This research has identified that spark plasma sintering technology makes it possible to obtain high-density samples, which contain a homogeneous microstructure and double the figure-of-merit values, for use in high-power piezoelectric devices that operate at piezoresonance frequencies. It also found that the addition of a small amount of CuNb2O6 (x = 0.025) to lead-free solid solutions leads to the formation of a liquid phase during sintering, thereby creating a compacted microstructure with relative density values (96%) that have practical limitations in conventional ceramic technology. An increase in both the piezoelectric and mechanical properties, which leads to a twofold increase in the values of the quality indicator, was also observed.Conclusions. It is possible to increase, and even to double, the functional characteristics of both lead-containing and lead-free ferroelectrically hard piezoceramics by varying the technology used in the manufacturing process. By using spark plasma sintering technology with lead-containing ceramics, it is possible to reduce the optimum sintering temperature by 200 °C and the sintering time by more than 20 times, thus reducing production costs.Цели. Сегнетожесткая пьезоэлектрическая керамика востребована при создании устройств, работающих в силовых режимах: пьезотрансформаторах, ультразвуковых излучателях и пьезодвигателях, что требует сочетания в ней высоких пьезоэлектрических характеристик и механической добротности. В этой работе на примере двух широко распространенных химических систем Pb(ZrxTi1-x)O3 и (Na1-xKx)NbO3 продемонстрированы принципиально различные химико-технологические пути формирования плотной микроструктуры и достижения наилучших, с точки зрения практических применений, наборов диэлектрических, пьезоэлектрических и механических параметров. В случае свинецсодержащей керамики были использованы различные технологии спекания: обычная керамическая, горячее прессование и искровое плазменное спекание. Для повышения функциональных характеристик бессвинцовой керамики был выбран путь, связанный с добавлением медьсодержащего компонента CuNb2O6 (x) к исходной системе ниобата натрия-калия. Целью настоящей работы стало выявление основных закономерностей формирования микроструктуры и функциональных характеристик сегнетожесткой керамики на основе систем Pb(ZrxTi1-x)O3 и (Na1-xKx)NbO3, при вариации технологических режимов их изготовления.Материалы. Микроструктура пьезоэлектрической керамики исследовалась методом электронной микроскопии, а функциональные характеристики оценивались по показателям механических и пьезоэлектрических свойств. Значения плотности определялись методом гидростатического взвешивания в октане, относительная диэлектрическая проницаемость была измерена с помощью LCR-метра, а значения пьезоэлектрического коэффициента и механической добротности установлены на основании резонансно-антирезонансного метода.Результаты. Установлено, что применение технологии искрового плазменного спекания позволяет получить высокоплотные образцы свинецсодержащей керамики с однородной микроструктурой и более чем в два раза возросшими значениями показателя качества (figure-of-merit) для ее использования в устройствах силовой пьезотехники, работающих на частотах пьезорезонанса. Обнаружено, что добавка небольшого количества CuNb2O6 (x = 0.025) к бессвинцовым твердым растворам приводит к образованию в процессе спекания жидкой фазы, в результате чего формируется уплотненная микроструктура с практически предельными для обычной керамической технологии значениями относительной плотности (96%). Наблюдается возрастание как пьезоэлектрических, так и механических свойств, что приводит к двукратному повышению значений показателя качества.Выводы. Вариация технологических режимов изготовления как свинецсодержащей, так и бессвинцовой сегнетожесткой пьезокерамики позволяет существенно (в два раза) повысить ее функциональные характеристики. Использование метода искрового плазменного спекания при изготовлениии свинецсодержащей керамики способствует сокращению как оптимальной температуры процесса на 200 °С, так и продолжительности изотермической выдержки более чем в 20 раз. Такой прием существенно снижает производственные затраты

Thinking lifecycle as an implementation of machine understanding in software maintenance automation domain

© Springer International Publishing Switzerland 2015. The main goal of our work is to test the feasibility study of automation of incident processing in Infrastructure as Service domain to optimize the operational costs of management services that are delivered remotely. This paper also describes a framework that authors have developed to deliver an integrated incident, problem solution and resolution approach as an event-driven Automated Incident Solving System, for Remote Infrastructure Management (RIM) Model. Current approaches are mainly automated scripts, but this is a specific approach for one specific problem. Those systems can’t think. Our approach is a system that exploits a thinking model thus can think and can learn. In other words system is capable of recombining its knowledge to solve new problems. Based on Minsky [11] thinking model we have created a machine understanding prototype which is capable of learning and understanding primitive incident description texts

Shift of the surface-barrier part of the irreversibility line due to columnar defects in Bi_2Sr_2CaCu_2O_8 thin films

We report the results of studying the influence of the uranium-ion irradiation of the Bi_2Sr_2CaCu_2O_8 thin films on the high-temperature part (close to critical temperature) of their irreversibility line. We studied irreversible properties of the films by measuring the hysteresis of nonresonant microwave absorption. The results have revealed the shift of irreversibility line towards low temperatures and magnetic fields. The effect is most significant for the films irradiated with large doses, more than 1T. This fact is in good agreement with the theoretical prediction by Koshelev and Vinokur of suppression of surface barrier by columnar defects.Comment: LaTeX2e, 9 pages with 3 figures, to be published in Physica