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排序方式: 共有289条查询结果,搜索用时 453 毫秒
21.
Karolin K. Kroening Douglas D. Richardson Scott Afton Joseph A. Caruso 《Analytical and bioanalytical chemistry》2009,393(8):1949-1956
Sulfur mustard (HD), bis(2-chloroethyl)sulfide, is one of a class of mustard agents which are chemical warfare agents. The
main chemical warfare hydrolysis degradation products of sulfur mustards are: thiodiglycol, bis(2-hydroxyethylthio)methane,
1,2-bis(2-hydroxyethylthio)ethane, 1,3-bis(2-hydroxyethylthio)propane, and 1,4-bis(2-hydroxyethylthio)butane. The aim of this
study is to identify these five hydrolysis degradation products utilizing reversed-phase high-performance liquid chromatography
coupled with inductively coupled plasma mass spectrometry (ICP-MS) for element-specific sulfur detection using a collision/reaction
cell and electrospray ionization mass spectrometry to confirm the identification. To date, this is the first study utilizing
ICP-MS with 32S element-specific detection for the analysis of vesicant chemical warfare agent degradation products. 相似文献
22.
《Stochastic Processes and their Applications》2019,129(11):4239-4268
We prove that loop-erased random walks on the finite pre-Sierpiński gaskets can be extended to a loop-erased random walk on the infinite pre-Sierpiński gasket by using the ‘erasing-larger-loops-first’ method, and obtain the asymptotic behavior of the walk as the number of steps increases, in particular, the displacement exponent and a law of the iterated logarithm. 相似文献
23.
In this paper, an adaptive FE analysis is presented based on error estimation, adaptive mesh refinement and data transfer for enriched plasticity continua in the modelling of strain localization. As the classical continuum models suffer from pathological mesh-dependence in the strain softening models, the governing equations are regularized by adding rotational degrees-of-freedom to the conventional degrees-of-freedom. Adaptive strategy using element elongation is applied to compute the distribution of required element size using the estimated error distribution. Once a new mesh is generated, state variables and history-dependent variables are mapped from the old finite element mesh to the new one. In order to transfer the history-dependent variables from the old to new mesh, the values of internal variables available at Gauss point are first projected at nodes of old mesh, then the values of the old nodes are transferred to the nodes of new mesh and finally, the values at Gauss points of new elements are determined with respect to nodal values of the new mesh. Finally, the efficiency of the proposed model and computational algorithms is demonstrated by several numerical examples. 相似文献
24.
S.B. Wang X.Y. Li Y.D. Cao D.S. Dong J.W. Tong L.A. Li C. Yue M. Shen 《Optics and Lasers in Engineering》2005,43(8):895-903
The paper presents a new method applied to measure displacement fields using mutual information concept. Based on analysis of digital image sequences, we propose the formulation derived from the mutual information between subsets in the un-deformed and deformed image. The quantity of the mutual information between two subsets establishes a criterion of their mutual dependence based on the notion of information connection between them. We can obtain the integer pixel displacement for the corresponding subset. And the accurate displacement field is obtained by using sub-pixel technique. In the experiments, the method is validated and the resulting solution can show accuracy to 0.02 pixels. This method was also applied successfully to determine the displacement fields of laminated composites of AS4/PEEK[0/±45/90]7s under uniaxial compression. 相似文献
25.
We describe a wave-front displacement system using a novel configuration of a pair of wedge prisms. The wave-front propagation, through the displacement system, is analyzed using the exact ray trace. The main advantage, of this configuration, is that the shearing (direction and magnitude) is constant from the displacement system to the image plane. The direction of the shearing depends on the relative orientation of the prisms. The magnitude of the shearing is proportional to the distance between prisms. The proportionality constant depends on the wedge angle and the material of fabrication of the prisms, and it gives the sensitivity to the displacement of the system. The deviation of the shearing due to the difference between the wedge angles is larger than that the produced by the oblique incidence of the wave-front. The experimental results confirm the theoretical data. 相似文献
26.
27.
A sinusoidal phase-modulating fiber-optic interferometer insensitive to the intensity change of the light source 总被引:1,自引:0,他引:1
Xuefeng Wang Xiangzhao Wang Yingming Liu Caini Zhang Danyang Yu 《Optics & Laser Technology》2003,35(3):219-222
In a conventional laser-diode sinusoidal phase-modulating (LD-SPM) interferometer, the wavelength of the LD is modulated by varying its injection current. The intensity modulation concurrent with the wavelength modulation leads to measurement errors. A photothermal-modulation method has been proposed to decrease the intensity change of the LD; however, this method cannot be used to measure vibration with a high frequency, and the beam diameter is too large to be used to measure minute objects. In this paper, we propose LD-SPM fiber-optic interferometer, in which the effect of the intensity change of the light source on measurement is eliminated. The diameter of the light beam is less than 0.5 mm. Using this interferometer, we measured displacements of a mirror driven by a piezoelectric transducer. The measurement repeatability is less than 1 nm. 相似文献
28.
Differential FBG sensor for temperature-compensated high-pressure (or displacement) measurement 总被引:2,自引:0,他引:2
A differential fiber Bragg grating (FBG) sensor with a free active element bulk-modulus for high-pressure (or displacement) measurement is presented. Based on the differential measurement method and an isosceles triangle cantilever structure, problems of cross-sensitivity and chirped signal in FBG sensor are improved both theoretically and experimentally. Preliminary experiments indicate that temperature-compensated measurement results agree well with the theoretical analysis. Displacement measurement sensitivity is 1.75 pm/μm, and the estimated pressure measurement resolution can reach 0.27 MPa in case the wavelength shift measurement resolution is 0.01 nm. 相似文献
29.
Theory and experiment of spatially and temporally partially coherent speckle shearing interferometry
The theory and experiment of spatially and temporally partially coherent speckle shearing interferometry is reported in this rapid communication for the first time. The general requirements for the surface roughness and coherence area of a diffuse object surface in spatially and temporally partially coherent speckle shearing interferometry are discussed. An experimental verification is presented and the results of theory and experiment are in good agreement. 相似文献
30.
Spatial aliasing may affect methods based on grid image processing to retrieve displacement and strain maps in experimental mechanics. Such methods aim at estimating these maps on the surface of a specimen subjected to a loading test. Aliasing, which is often not noticeable to the naked eye in the grid images, may give spurious fringes in the strain maps. This paper presents an analysis of aliasing in this context and provides the reader with simple guidelines to minimize the effect of aliasing on strain maps extracted from grid images. 相似文献