3,022 research outputs found

    Controllable Andreev retroreflection and specular Andreev reflection in a four-terminal graphene-superconductor hybrid system

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    We report the investigation of electron transport through a four-terminal graphene-superconductor hybrid system. Due to the quantum interference of the reflected holes from two graphene-superconductor interfaces with phase difference θ\theta, it is found that the specular Andreev reflection vanishes at θ=0\theta=0 while the Andreev retroreflection disappears at θ=π\theta=\pi. This means that the retroreflection and specular reflection can be easily controlled and separated in this device. In addition, due to the diffraction effect in the narrow graphene nanoribbon, the reflected hole can exit from both graphene terminals. As the width of nanoribbon increases, the diffraction effect gradually disappears and the reflected hole eventually exits from a particular graphene terminal depending on the type of Andreev reflection.Comment: 4 pages, 5 figure

    Investigation on dynamic characteristics of mechanical assembly

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    Mechanical assembly is important process affecting product dynamic quality. To completely inspect assembly quality, dynamic characteristic analysis is necessary. Based on substructuring dynamic analysis, this paper theoretically analyzes the changes of dynamic characteristics due to assembling process. Assembly coupling dynamic stiffness computed by inverse substructuring analysis is considered as a critical measure on the changes. The results obtained have been well validated by a lumped-parameter model for two-level of substructures

    Estudio piloto de intervención de enfermería radiológica en examen de resonancia magnética 3-t

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    OBJETIVO Se objetivó investigar el efecto de la intervención de enfermería radiológica en examen abdominal de IRM 3-T. MÉTODO Sesenta pacientes con enfermedades abdominales fueron divididos aleatoriamente en dos grupos: grupo intervención de enfermería RM y grupo control. Todos fueron sometidos a examen abdominal de RM 3-T. Las intervenciones de enfermería RM se efectuaron en el grupo establecido. Los resultados, incluyendo tasa de éxito en única vez, relación de imágenes de RM diagnosticables y puntos de calidad de imagen, fueron comparadas entre ambos grupos. RESULTADOS La tasa de éxito en única vez en grupo control y grupo intervención de enfermería RM fueron de 66,67% y 96,67%, expresando diferencias significativas (χ2 =9.017, POBJETIVO O objetivo deste estudo foi investigar o resultado da intervenção de enfermagem na radiologia em exame de ressonância magnética (RM) abdominal 3 Tesla. MÉTODO 60 pacientes com patologias abdominais foram aleatoriamente divididos em dois grupos: grupo de intervenção de enfermagem em RM e grupo controle. Todos os pacientes foram submetidos ao exame de RM abdominal 3 Tesla. As intervenções de enfermagem em RM foram realizadas no grupo de intervenção de enfermagem. Os resultados foram comparados entre os dois grupos, incluindo a taxa de sucesso único, o coeficiente das imagens de RM diagnosticáveis e os pontos da qualidade de imagem. RESULTADOS As taxas de sucesso único no grupo controle e no grupo de intervenção de enfermagem em RM foram 66,67% e 96,67%, com diferença significativa de (χ2 =9,017, POBJECTIVE The aim of this study was to investigate the effect of radiology nursing intervention in abdominal examination at 3-T MRI. METHOD 60 patients with abdominal diseases were divided into two groups randomly: MR nursing intervention group and control group. All the patients underwent abdominal MR examination at 3-T. The MR nursing interventions were performed in nursing intervention group. The outcomes, including one-time success rate, the ratio of diagnosable MR images and the points of image quality, were compared between these two groups. RESULTS The one-time success rates in control group and MR nursing intervention group were 66.67% and 96.67% with significant difference ( χ2 =9.017,

    Zc(3900)Z_c(3900) as a DDˉD\bar{D}^* molecule from the pole counting rule

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    A comprehensive study on the nature of the Zc(3900)Z_c(3900) resonant structure is carried out in this work. By constructing the pertinent effective Lagrangians and considering the important final-state-interaction effects, we first give a unified description to all the relevant experimental data available, including the J/ψπJ/\psi\pi and ππ\pi\pi invariant mass distributions from the e+eJ/ψππe^+e^-\to J/\psi\pi\pi process, the hcπh_c\pi distribution from e+ehcππe^+e^-\to h_c\pi\pi and also the DDˉD\bar D^{*} spectrum in the e+eDDˉπe^+e^-\to D\bar D^{*}\pi process. After fitting the unknown parameters to the previous data, we search the pole in the complex energy plane and find only one pole in the nearby energy region in different Riemann sheets. Therefore we conclude that Zc(3900)Z_c(3900) is of DDˉD\bar D^* molecular nature, according to the pole counting rule method~[Nucl.~Phys.~A543, 632 (1992); Phys.~Rev.~D 35,~1633 (1987)]. We emphasize that the conclusion based upon the pole counting method is not trivial, since both the DDˉD\bar D^{*} contact interactions and the explicit ZcZ_c exchanges are introduced in our analyses and they lead to the same conclusion.Comment: 21 pages, 9 figures. To match the published version in PRD. Additional discussion on the spectral density function is include

    Device modeling of superconductor transition edge sensors based on the two-fluid theory

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    In order to support the design and study of sophisticated large scale transition edge sensor (TES) circuits, we use basic SPICE elements to develop device models for TESs based on the superfluid-normal fluid theory. In contrast to previous studies, our device model is not limited to small signal simulation, and it relies only on device parameters that have clear physical meaning and can be easily measured. We integrate the device models in design kits based on powerful EDA tools such as CADENCE and OrCAD, and use them for versatile simulations of TES circuits. Comparing our simulation results with published experimental data, we find good agreement which suggests that device models based on the two-fluid theory can be used to predict the behavior of TES circuits reliably and hence they are valuable for assisting the design of sophisticated TES circuits.Comment: 10pages,11figures. Accepted to IEEE Trans. Appl. Supercon

    Assessing the effectiveness of complex dietary candidate probiotics on growth performance, digestive enzyme activity, antioxidant capability, and intestinal microbiota of koi carp (Cyprinus carpio var. koi)

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    The present study aimed to evaluate the effectiveness of three complex dietary candidate probiotics (LDJ, LAC, and LJD) composing different candidate probiotic combinations on the growth performance, digestive enzyme activities, antioxidant parameters, and intestinal microbiota in koi carp (Cyprinus carpio var. koi). After a 60-days feeding trial, samples from the control and three candidate probiotic groups were obtained and analyzed. The results suggested that all complex dietary candidate probiotic treatments (LDJ, LAC, and LJD) improved the growth performance, nutrition utilization, and intestinal digestive enzyme activities compared with the control group. Furthermore, a dietary supplement with LAC or LJD is more efficient in growth and digestive enzyme than LDJ. The antioxidant enzyme activities, including SOD (superoxide dismutase), CAT (catalase), and GPX (glutathione peroxidase), were intensively improved, the GSH (glutathione) contents increased, and the MDA (malondialdehyde) contents decreased to different extents depending on the tissues and kinds of candidate probiotics. Dietary candidate probiotics also regulated the intestinal microbiota composition: LDJ and LAC increased the proportion of potential candidate probiotics and reduced the level of pollutants reducing bacteria and geosmin producer Nannocystis. The LJD group had a similar pattern of the dominant bacteria to the control sample, suggesting a minor disturbance of the gut microbiota of koi carp. Overall, the multi-strain complex candidate probiotics LAC and LJD are more efficient in growth performance and digestive enzymes

    Determining coupling dynamic stiffness of structural connection by tested FRFs

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    Identifying coupling dynamic stiffness of structural connection is often needed in substructural dynamic analysis. To overcome the faultiness of conventional approaches existed, five indirect schemes of inverse substructuring analysis by using tested frequency response functions (FRFs) are provided. And the first indirect scheme is verified by three mass-rubber models constructed as two-level substructures with mono-coupling, bi-coupling and tri-coupling connection. Compared to existing direct scheme of inverse substructuring analysis, it shows better performance with acceptable precision of determining the stiffness
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