776 research outputs found

    Biharmonic Riemannian submersions from 3-manifolds

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    An important theorem about biharmonic submanifolds proved independently by Chen-Ishikawa [CI] and Jiang [Ji] states that an isometric immersion of a surface into 3-dimensional Euclidean space is biharmonic if and only if it is harmonic (i.e, minimal). In a later paper [CMO2], Cadeo-Monttaldo-Oniciuc shown that the theorem remains true if the target Euclidean space is replaced by a 3-dimensional hyperbolic space form. In this paper, we prove the dual results for Riemannian submersions, i.e., a Riemannian submersion from a 3-dimensional space form of non-positive curvature into a surface is biharmonic if and only if it is harmonic

    Micromachined Electric Field Mill Employing a Vertical Moving Shutter

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    AbstractThis paper presents a new type of micromachined electric field mill (MEFM) for measuring dc electric fields. This MEFM employs thermal actuators for vertical movement of an electrically grounded shutter, to mill the amplitude of a dc electric field incident on underlying sense electrodes. It addresses the main drawbacks of existing MEFMs, which are shutter displacement in large electric field, and drive signal interference from the shutter actuator. Simulation results show that for a 1kV/m dc field the output of the sensor is about 1pA

    Stomach One-Point Cancer: One Case Report and Literature Review

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    Gastric cancer is one of the most common cancers and one of themost frequent causes of cancer deaths worldwide. Early detection andaccurate preoperative staging of gastric cancer is essential for planning optimal therapy such as endoscopic mucosal resection or gastric resection and offers the best prognosis. With advanced technology in diagnostic instruments and the mass screening, early gastric cancer has been detected easier. One-point cancer of gastric is a special type of early gastric cancer[1]. Diagnosis of one-point cancer of gastric is important for both the immediate treatment and the prognosis. There is still no consensus on the operation extent and postoperative treatment for patients with one-point cancer of gastric. Learned from previous reports[2-5], we know that existed in the superfi cial layer of the gastric mucosa and the superfi cial ulcer is one of the important characteristics of one point cancer of gastric. Herein, we report a case of one point cancer of gastric with the appearance of a deep infi ltrating ulcer. To the best of our knowledge, no such type of one point cancer of gastric has been reported

    Surface Properties of SiCp/Al Composite by Powder-Mixed EDM

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    AbstractThis paper uses a kind of moderate volume fraction (40%) of SiC particle reinforced Al matrix composites (SiCp/Al) to research how the surface properties are affected in conventional EDM (EDM) and powder-mixed EDM (PMEDM). By means of environment scanning electron microscope (ESEM) and HIT friction and wear tester, surface micro-topography, elements and wear resistance were analyzed. Experiments and researches indicate that compared with EDM, the surface properties machined by using PMEDM are improved greatly. The PMEDM surface roughness decreases about 31.5%; corrosion resistance is better too; and wear resistance is twice of EDM. Powder-mixed EDM has promising applications in metal matrix composites machining field

    Prediction of a High Temperature Bonding Condition at the Interface for the Hot-Rolled Stainless Steel Clad Plate on Rolling

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    The stainless steel-carbon steel clad plate was investigated using the theoretical analysis of various factors influencing the high-temperature interfacial bonding during its rolling. Phenomenological prediction analysis model of interfacial bonding strength at high temperature which considers the vacuum depth, rolling temperature, and rolling reduction, was established. The specific thermal simulation experiment was designed, the bonding strength of carbon steel and stainless steel at 1000~1200°C and compression degree of 10~30% was measured by a Gleeble 3500 thermal simulator, as a result, the interfacial bonding ratio was obtained. The results show that the bonding ratio is 0.5-0.65 at the experimental temperature and compression degree. The numerical simulation method was used to analyze the influence of the compression degree of the first pass for a 2000×1500×100 mm stainless steel clad plate under the interfacial bonding condition. The simulation results show that the optimum compression degree of the first pass is 15-20% at the rolling temperature of 1200°C.Листовая углеродистая сталь, плакированная нержавеющей сталью, исследована с помощью теоретического анализа различных факторов, влияющих на высокотемпературное межповерхностное сцепление при ее прокатке, феноменологической модели прогнозного анализа прочности межповерхностного сцепления при высокой температуре, которая учитывает глубину разрежения, температуру прокатки и обжатие при прокатке. Подготовлен специальный эксперимент с моделированием температурного режима, прочность сцепления углеродистой и нержавеющей сталей при 1000–1200°С и степени обжатия 10~30% измерена с помощью моделирующего устройства с регулируемым температурным режимом Gleeble 3500, получена относительная прочность межповерхностного сцепления. Показано, что при температуре и степени обжатия, принятых в эксперименте, относительная прочность сцепления составляет 0.50–0.65. Метод численного моделирования использован для анализа влияния степени обжатия за первый пропуск пластины плаплакированной нержавеющей сталью размером 2000×1500×100 мм на межповерхностное сцепление. Оптимальная степень обжатия за первый пропуск составляет 15–20% при температуре прокатки 1200°С

    Spin diffusion in nn-type (111) GaAs quantum wells

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    We utilize the kinetic spin Bloch equation approach to investigate the steady-state spin diffusion in nn-type (111) GaAs quantum wells, where the in-plane components of the Dresselhaus spin-orbit coupling term and the Rashba term can be partially canceled by each other. A peak of the spin diffusion length due to the cancellation is predicted in the perpendicular electric field dependence. It is shown that the spin diffusion length around the peak can be markedly controlled via temperature and doping. When the electron gas enters into the degenerate regime, the electron density also leads to observable influence on the spin diffusion in the strong cancellation regime. Furthermore, we find that the spin diffusion always presents strong anisotropy with respect to the direction of the injected spin polarization. The anisotropic spin diffusion depends on whether the electric field is far away from or in the strong cancellation regime.Comment: 5 pages, 3 figures, to be published in Solid State Commu

    Selection and validation of emotional videos: Dataset of professional and amateur videos that elicit basic emotions

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    This article describes the process of selecting a collection of professional and amateur videos that elicit five basic emotions (i.e., happiness, fear, disgust, anger, and sadness) and validating these videos in three groups of participants (i.e., Chinese from China, Chinese from Malaysia, and Bumiputera from Malaysia). In the video selection phase, professional videos, which were Western movie trailers, were selected from IMDb (Internet Movie Database) and amateur videos were selected from YouTube. The researchers selected videos that display five basic emotions, identified the time frames with the strongest display of emotion, and rated the emotional intensity of each video on a 5-point Likert scale. After the initial stage of selection, two other researchers performed an emotion recognition task by watching the videos without audio to ensure that the emotions can be elicited without understanding the language. This data was used to refine the final selection of 20 professional videos and 20 amateur videos. In the video validation phase, 30 participants were asked to identify and rate the intensity of emotion felt. This article includes a description of the video selection method, a detailed list of the videos selected, and participants' responses and ratings of emotional intensity for the 40 videos

    CFD simulations of the spent fuel pool in the loss of coolant accident

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    Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.The study utilized the computational fluid dynamics (CFD) methodology to investigate the thermal hydraulic behavior during the hypothetical event of normal operation and loss of cooling accident occurring at spent fuel pool. The boiling time, water level decreasing rate, fuel exposure time and temperature response after fuel exposure for the nuclear power plants under the accident were predicted in this study. We also analyze the flow and heat transfer for the single Atrium-10 fuel bundle. The details of the physics will be shown in this study. The results indicate that the fuel temperature in the pool will not exceed 1200°C to avoid the water-metal reaction after failure of RHR system for 4.578 days. We find that the velocity in the bundle are much faster than outside of the bundle under the LOCA accident.dc201

    The Conformal Willmore Functional: a Perturbative Approach

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    The conformal Willmore functional (which is conformal invariant in general Riemannian manifold (M,g)(M,g)) is studied with a perturbative method: the Lyapunov-Schmidt reduction. Existence of critical points is shown in ambient manifolds (R3,gϵ)(\mathbb{R}^3, g_\epsilon) -where gϵg_\epsilon is a metric close and asymptotic to the euclidean one. With the same technique a non existence result is proved in general Riemannian manifolds (M,g)(M,g) of dimension three.Comment: 34 pages; Journal of Geometric Analysis, on line first 23 September 201
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