2,710 research outputs found

    Frohlich mass in GaAs-based structures

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    The Frohlich interaction is one of the main electron-phonon intrinsic interactions in polar materials originating from the coupling of one itinerant electron with the macroscopic electric field generated by any longitudinal optical (LO) phonon. Infra-red magneto-absorption measurements of doped GaAs quantum wells structures have been carried out in order to test the concept of Frohlich interaction and polaron mass in such systems. These new experimental results lead to question the validity of this concept in a real system.Comment: 4 pages, 3 figure

    Advancing Science with VGI: Reproducibility and Replicability of Recent Studies using VGI

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    In scientific research, reproducibility and replicability are requirements to ensure the advancement of our body of knowledge. T his holds true also for VGI - related research and studies. However, the characteristics of VGI suggest particular difficulties in ensuring reproducibility and replicability . In this paper, we aim to examine the current situation in VGI - related research , and identify strategies to ensure realization of its full potential. To do so, we first investigate the different aspects of reprod ucibility and replicability and their impact on VGI - related research . These impacts are different depending on the objectives of the study. Therefore , we examine the study focus of VGI - related research to assess the current body of research and structure o ur assessment . Th is work is based on a rigorous review of the elements of reproducibility and a systematic mapping and analysis of 58 papers on the use of VGI in the crisis management field. Results of our investigation show that reproducibility issues related to data are a serious concern , while reproducibility issues related to analysis methods and processes face fewer challenges. Howe ver, since most studies still focus on analyzing the source data, reproducibility and replicability are still an unsolved problem in VGI - related research. Therefore, we show initiative s tackling the problem, and finally formulate strategies to improve the situatio

    Расчет ГИН по схеме Аркадьева-Маркса

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    Объектом исследования является генератор импульсного напряжения по схеме Аркадьева-Маркса. Цель работы: спроектировать и рассчитать генератор импульсных напряжений. В процессе работы рассчитаны количественные значения элементов ГИНа: значения коэффициентов использования разрядной схемы и волны; емкость и индуктивность конденсатора; количество ступеней; фронтовое и разрядное сопротивления. Был выполнен расчет ресурсов, ставки налогов, отчислений. Так же было описаны рабочее место и законодательные и нормативные документы.The object of study is the generator of pulse voltage according to the scheme Arkadiev-Marx. Objective: to design and calculate the voltage impulse generator. In the process, the calculated quantitative values of the elements of a Hin: the coefficients of use of the discharge circuit and wave; the capacitance and inductance of the capacitor; number of steps; the front and discharge resistors. Calculated resources, tax rates, deductions. As described workplace and legislative and regulatory documents

    An Analysis of the Next-to-Leading Order Corrections to the g_T(=g_1+g_2) Scaling Function

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    We present a general method for obtaining the quantum chromodynamical radiative corrections to the higher-twist (power-suppressed) contributions to inclusive deep-inelastic scattering in terms of light-cone correlation functions of the fundamental fields of quantum chromodynamics. Using this procedure, we calculate the previously unknown O(αs){\cal O}(\alpha_s) corrections to the twist-three part of the spin scaling function gT(xB,Q2)(=g1(xB,Q2)+g2(xB,Q2))g_T(x_B,Q^2) (=g_1(x_B,Q^2)+g_2(x_B,Q^2)) and the corresponding forward Compton amplitude ST(ν,Q2)S_T(\nu,Q^2). Expanding our result about the unphysical point xB=x_B=\infty, we arrive at an operator product expansion of the nonlocal product of two electromagnetic current operators involving twist-two and -three operators valid to O(αs){\cal O}(\alpha_s) for forward matrix elements. We find that the Wandzura-Wilczek relation between g1(xB,Q2)g_1(x_B,Q^2) and the twist-two part of gT(xB,Q2)g_T(x_B,Q^2) is respected in both the singlet and non-singlet sectors at this order, and argue its validity to all orders. The large-NcN_c limit does not appreciably simplify the twist-three Wilson coefficients.Comment: 41 pages, 9 figures, corrected minor erro

    Comparing behavior under risk and under ambiguity in a lifecycle experiment

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    Experiments on intertemporal consumption typically show that people have difficulties in optimally solving such problems. Previous studies have focused on contexts in which agents are faced with risky future incomes and have to plan over long horizons. We present an experiment comparing decision making under certainty, risk, and ambiguity, over a shorter lifecycle. Results show that behavior in the ambiguity treatment is markedly different than in the risk condition and it is characterized by a significant pattern of under-consumption

    Cellular automaton supercolliders

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    Gliders in one-dimensional cellular automata are compact groups of non-quiescent and non-ether patterns (ether represents a periodic background) translating along automaton lattice. They are cellular-automaton analogous of localizations or quasi-local collective excitations travelling in a spatially extended non-linear medium. They can be considered as binary strings or symbols travelling along a one-dimensional ring, interacting with each other and changing their states, or symbolic values, as a result of interactions. We analyse what types of interaction occur between gliders travelling on a cellular automaton `cyclotron' and build a catalog of the most common reactions. We demonstrate that collisions between gliders emulate the basic types of interaction that occur between localizations in non-linear media: fusion, elastic collision, and soliton-like collision. Computational outcomes of a swarm of gliders circling on a one-dimensional torus are analysed via implementation of cyclic tag systems
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