排序方式: 共有18条查询结果,搜索用时 31 毫秒
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WANG Jiang FAUTRELLE Yves REN Zhong-ming LI Xi NGUYEN-THI Henri MANGELINCK-NOEL Nathalie SALLOUM ABOU JAOUDE Georges ZHONG Yun-bo KALDRE Imants BOJAREVICS Andris BULIGINS Leonid 《钢铁研究学报(英文版)》2012,(Z1):381-385
Sn-3wt%Pb alloy was directionally solidified without and with a 0.08T transverse magnetic field(TMF),and real-time recorded by in-situ synchrotron X-ray imaging.Results indicate that TMF shortened the distance from the location of nucleation to the advancing interface,and accelerated the growth rate of the equiaxed crystal,which caused the columnar-to-equiaxed transition(CET)finally.The thermoelectromagnetic convection(TEMC)in front of the interface and around the crystal’s dendritic branch should respond to changes of the distance and the growth rate. 相似文献
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Xie Xu Zhong Ming Kaldre Imants Qu Zhiguo Wang Dongming Wang Cong 《Metallurgical and Materials Transactions A》2023,54(4):1077-1082
Metallurgical and Materials Transactions A - Microstructural evolution roadmap in the weld metal of EH420 shipbuilding steel subjected to various reheating inputs has been investigated. As... 相似文献
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Chandra SS Svalbe ID Guedon J Kingston AM Normand N 《IEEE transactions on image processing》2012,21(10):4431-4441
The discrete Fourier transform (DFT) underpins the solution to many inverse problems commonly possessing missing or unmeasured frequency information. This incomplete coverage of the Fourier space always produces systematic artifacts called Ghosts. In this paper, a fast and exact method for deconvolving cyclic artifacts caused by missing slices of the DFT using redundant image regions is presented. The slices discussed here originate from the exact partitioning of the Discrete Fourier Transform (DFT) space, under the projective Discrete Radon Transform, called the discrete Fourier slice theorem. The method has a computational complexity of O(nlog(2)n) (for an n=N×N image) and is constructed from a new cyclic theory of Ghosts. This theory is also shown to unify several aspects of work done on Ghosts over the past three decades. This paper concludes with an application to fast, exact, non-iterative image reconstruction from a highly asymmetric set of rational angle projections that give rise to sets of sparse slices within the DFT. 相似文献
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Imants Svalbe 《Pattern recognition letters》2011,32(9):1415-1420
The Finite Radon Transform (FRT) is a discrete analogue of classical tomography. The FRT permits exact reconstruction of a discrete object from its discrete projections. The set of projection angles for the FRT is intrinsic to each image array size. It is shown here that the set of FRT angles is closed under a rotation by any of its members. A periodic re-ordering of the elements of the 1D FRT projections is then equivalent to an exact 2D image rotation. FRT-based rotations require minimal interpolation and preserve all of the original image pixel intensities. This approach has applications in image feature matching, multi-scale data representation and data encryption. 相似文献
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In Part 1 of a 2-part study, computer-accessible Canadian free association norms in French ( N = 300) and in English ( N = 300) were compared for several parameters, including a measure of response diversity (alpha). English-speaking Ss showed a strong tendency to response communality, producing response hierarchies which were considerably less diversified than those of the French-speaking sample. These differences were attributed to culturally induced response sets to choose either popular or original responses as associations. Part 2 compared the Montreal French-Canadian norms to 2 sets of norms from 288 French students and 115 workers in the Paris region. Each of these Francophone samples produced a mean response frequency distribution which was different in shape from the others. These differences were in sharp contrast to the high degree of intergroup agreement typically found for English-speaking samples of diverse origins. (French summary) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Andria SE Richardson JN Kaval N Zudans I Seliskar CJ Heineman WR 《Analytical chemistry》2004,76(11):3139-3144
We report herein an attenuated total reflectance (ATR) absorbance-based spectroelectrochemical sensor for tris(2,2'-bipyridyl)ruthenium(II) ion [Ru(bpy)(3)(2+)] that employs ultrathin (24-50 nm) Nafion films as the charge-selective layer. This film serves to sequester and preconcentrate the analyte at the optically transparent electrode surface such that it can be efficiently detected optically via electrochemical modulation. Our studies indicate that use of ultrathin films in tandem with continuous flow of sample solution through the cell compartment leads to a 100-500-fold enhancement in detection limit (10 nM) compared to earlier absorbance-based spectroelectrochemical sensors ( approximately 1-5 microM); markedly shorter analysis times also result. We report the dependence of the measured absorbance on sample flow rate and Nafion film thickness, and also provide calibration curves that illustrate the linear range and detection limits of the sensor using a 24 nm film at a constant sample flow rate of 0.07 mL/min. 相似文献
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A549 cells were briefly exposed to Thioglo-1, which converts thiols to fluorescent adducts. The fluorescent cells were exposed to short (50-300 ms) electric field pulses (500 V across a 15 cm capillary) created at the tip of an electrolyte-filled capillary. Fluorescence microscopy revealed varying degrees of cell permeabilization depending on the conditions. Longer pulses and a shorter cell-capillary tip distance led to a greater decrease in the cell's fluorescence. Live/dead (calcein AM and propidium iodide) testing revealed that a certain fraction of cells died. Longer pulses and shorter cell-capillary tip distances were more deadly. An optimum condition exists at a cell-capillary tip distance of 3.5-4.5 microm and a pulse duration of 120-150 ms. At these conditions, >90% of the cells are permeabilized and 80-90% survive. 相似文献
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The transport of Pb2+ through a sensory gel, a polymerized crystalline colloidal array hydrogel with immobilized benzo-18-crown-6, is important for understanding and optimizing the sensor. Square wave voltammetry at a Hg/Au electrode reveals many parameters. The partition coefficient for Pb2+ into a control gel (no crown ether), K(p), is 1.00 +/- 0.018 (errors reported are SEM). The porosity, epsilon, of the gel is 0.90 +/- 0.01. Log K(c) for complexation in the gel is 2.75 +/- 0.014. Log K(c) in aqueous solution for Pb2+ with the ligand 4-acryloylamidobenzo-18-crown-6 is 3.01 +/- 0.010 with dissociation rate k(d) = (8.34 +/- 0.45) x 10(2) s(-1) and association rate k(f) = (8.79 +/- 0.025) x 10(7) M(-1) s(-1). The partition coefficient of the ligand 4-acryloylamidobenzo-18-crown-6 into the control gel, K(p,L) is 2.07 +/- 0.15. The diffusion coefficient of Pb2+ in the control gel is 6.72 x 10(-6) +/- 0.12 cm(2)/s. For the sensor gel, but not control gel, diffusion coefficients are location dependent. The range of diffusion coefficients for Pb2+ in the probed locations was found to be (6.11-12.60) x 10(-7) cm(2)/s for 0.91 mM Pb2+ and (2.84-9.39) x 10(-7) cm(2)/s for 0.35 mM Pb2+. Lead binding in the sensor gel is slightly less avid than in solution. This is attributed, in part, to the demonstrated affinity of the ligand 4-acryloylamidobenzo-18-crown-6 to the gel. Diffusion coefficients determined for the sensor gel were found to be location dependent. This is attributed to heterogeneities in the crown concentration in the gel. Analysis of diffusion coefficients and rate constants show that diffusion and not chemical relaxation will limit the time response of the material. 相似文献
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Peter J. Redlich W. Roy Jackson Frank P. Larkins Alan L. Chaffee Imants Liepa 《Fuel》1989,68(12):1538-1543
A suite of Victorian brown coals and the guest and host components of the coals obtained by 320 °C extraction have been reacted to obtain oils for analysis by n.m.r. and g.c.-m.s. techniques. Batch autoclave experiments without solvent, but with 10 MPa initial hydrogen pressure in the presence of stannic oxide, were undertaken at 405 °C. Oils derived from the macromolecular host material were highly polar materials and contained mainly phenols, and one- and two-ring aromatic hydrocarbons. They were of similar composition for all Victorian low-sulphur brown coals. In contrast, oils derived from the guest material were mainly a mixture of n-alkanes and terpenoid-derived cyclic hydrocarbons, and the ratio of these two types of compounds varied with the coal. 相似文献