共查询到20条相似文献,搜索用时 15 毫秒
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Lars Müller‐Meskamp Silvia Karthäuser Harold J. W. Zandvliet Melanie Homberger Ulrich Simon Rainer Waser 《Small (Weinheim an der Bergstrasse, Germany)》2009,5(4):496-502
The electrical properties of α,ω‐mercaptoalkyl ferrocenes with different alkyl chain lengths embedded in a self‐assembled host matrix of alkanethiols on Au(111) are studied by scanning tunneling microscopy and spectroscopy. Based on current–distance spectroscopy, as well as on the evaluation of Fowler–Nordheim tunneling current oscillations, the apparent barrier height of ferrocene is determined independently by two methods. The electronic coupling of the ferrocene moiety to the Au(111) substrate is shown to depend on the length of the alkane‐spacer chain. In a double tunnel junction model our experimental findings are explained, addressing the role of the different molecular moieties of the mercaptoalkyl ferrocenes. 相似文献
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A comparison is made between the measured α/β phase fractions in Ti-6246 using X-ray diffraction (XRD) and electron microscopy. Image analysis of SEM and TEM images was compared to the phase fraction estimate obtained using electron backscattered diffraction, lab and high-energy synchrotron XRD. There was a good agreement between the electron microscopic and diffraction techniques, provided that the microstructural parameters of grain size and texture are estimated correctly when using quantitative Rietveld refinement. 相似文献
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Xiaoqing Zheng Chaoqun Liu Feng Liu Cheng-I Yang 《International journal for numerical methods in engineering》1998,42(5):907-926
This paper describes a novel approach in simulating laminar to turbulent transition by using two-equation models. The Total Stresses Limitation (TSL) concept is used to make the two-equation model capable of predicting high-Reynolds-number transitional flow. In order to handle the transition triggered by laminar separation at a low Reynolds number location, which commonly occurs in high speed flow, a sensor is introduced to detect separation and trigger transition in the separated zone. Test cases include the classical flat-plate turbulent boundary flow, and low-pressure turbine cascade flows at design and off-design conditions. © 1998 John Wiley & Sons, Ltd. 相似文献
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Hiroshi Miyahara Morishige Mizuno Tamaki Watanabe 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1985,228(2-3):397-401
An attempt is made to calculate an efficiency function applicable to 4πβ-γ coincidence measurements as the first stage of evaluating the order of the polynomial of the fitting function. For this purpose, the β-ray energy spectra and self-absorptions of spherical particle sources are calculated by the Monte Carlo simulation under the continuous slowing down approximation. On the other hand, it is shown that three sets of absorption coefficients and partial intensity ratios corresponding to a β-ray group give analytically the self-absorption for the same particle sources. Finally, we show that the efficiency functions applicable to 59Fe and 134Cs are easily obtained by using the energy spectra or self-absorptions. 相似文献
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H. C. Yildirim G. B. Marquis 《Fatigue & Fracture of Engineering Materials & Structures》2014,37(5):561-569
This paper presents further assessments of the previously reported round‐robin fatigue data obtained from high‐frequency mechanical impact (HFMI)‐improved longitudinal welds. A detailed statistical analyses of geometry measurements of HFMI‐treated weld toe profiles are presented. The fatigue analyses based on notch stress as defined by the International Institute of Welding are performed using the finite element method. Notch stresses are assessed based on both the fictitious weld toe radius and the addition of measured actual notch radius to the fictitious radius. While no large differences are observed between the results of methods, the former one is found to be more practical and faster to implement from the end‐user point of view. 相似文献
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M.A. Saettel A. Sellam A. Nourreddine A. Pape 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2008,590(1-3):151
The RaMsEs Group (Radioprotection et Mesures Environnementales) of the IPHC performs research and offers services mainly in the field of radioactivity measurements and sample analysis. This report will describe some of our recent experience using a semiautomatic evaporation system to prepare large area thin deposits for total α and β counting and gives experimental and simulated results for the autoabsorption coefficients. 相似文献
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The present investigation is concerned with the three metastable austenitic steels AISI 304 (X5CrNi1810), 321 (X6CrNiTi1810), and 348 (X10CrNiNb189). In the temperature range ?60 °C ≤ T ≤ 25 °C tensile and fatigue tests were performed to characterize the mechanical and phase transformation behavior using stress‐elongation, stress–strain hysteresis, and magnetic measurements. The mechanical properties are significantly influenced by the temperature dependent deformation induced phase transformation from austenite to α′‐martensite which are combined with pronounced hardening processes. Furthermore microhardness measurements after fracture could be correlated with the results of the fatigue tests. 相似文献
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Bin Liu Yunping Li Hiroaki Matsumoto Yuichiro Koizumi Yong Liu Akihiko Chiba 《Advanced Engineering Materials》2012,14(9):785-789
This study reports a novel forging process to fabricate bulk fine‐grained (grain size ≈ 1 µm) Ti–6Al–4V alloy, in which temperatures near the β transus (Tβ) and strain rates around 0.15 s?1 are used for the deformation. The formation of fine‐grained microstructure is mainly result from the deformation‐induced precipitation of α grains from the β matrix. 相似文献