Parallel Plate Interferometer with a Reflecting Mirror for Measuring Angular Displacement

A parallel plate interferometer with a reflecting mirror for measuring angular displacement is proposed. A deflection angle of a beam caused by an angular displacement is amplified by use of a reflecting mirror to increase the optical path difference (OPD) in the plane-parallel plate, which provides high sensitivity of the phase measurement. Detection of light transmitted through the plane-parallel plate with a position sensitive detector (PSD) enables high accurate measurement of the initial angle of incidence to the plane-parallel plate with insensitivity to stray light. The improved parallel plate interferometer achieves a measurement repeatability of 10⁻⁸ rad.     

SUPERCONVERGENCE OF THE FULL-DISCRETE F.E.M. FOR COMPRESSIBLE MISCIBLE DISPLACEMENT: THE FULL TENSOR CASE

1　ＩｎｔｒｏｄｕｃｔｉｏｎＷｅｓｈａｌｌｃｏｎｓｉｄｅｒｔｈｅｍｏｄｅｌｆｏｒｍｉｓｃｉｂｌｅｄｉｓｐｌａｃｅｍｅｎｔｏｆｏｎｅｃｏｍｐｒｅｓｓｉｂｌｅｆｌｕｉｄｂｙａｎｏｔｈｅｒｉｎａｈｏｒｉｚｏｎｔａｌｒｅｓｅｒｖｏｉｒΩ Ｒ2 ｏｆｕｎｉｔｔｈｉｃｋｎｅｓｓｄｅｓｃｒｉｂｅｄｂｙｔｈｅｎｏｎｌｉｎｅａｒｐａｒａｂｏｌｉｃｓｙｓｔｅｍ[6]ｄ(ｃ) ｐ ｔ+ ·ｕ =ｄ(ｃ) ｐ ｔ- · (ａ(ｃ) ｐ) =ｑ ,(1.1)φ ｃ ｔ+ｂ(ｃ) ｐ ｔ+ｕ· ｃ - · (Ｄ(ｕ) ｃ =(^ｃ -ｃ)ｑ ,(1.2 )ｕ·ν =(Ｄ(ｕ) ｃ-ｃｕ)…     

Godunov–mixed methods for immiscible displacement

The immiscible displacement problem in reservoir engineering can be formulated as a system of partial differential equations which includes an elliptic pressure–velocity equation and a degenerate parabolic saturation equation. We apply a sequential numerical scheme to this problem where time splitting is used to solve the saturation equation. In this procedure one approximates advection by a higher-order Godunov method and diffusion by a mixed finite element method. Numerical results for this scheme applied to gas–oil centrifuge experiments are given.     

A time-stepping procedure based on convolution for the mixed finite element approximation for porous media flow

A time-stepping procedure is established and analyzed for the problem of miscible displacement in porous medium. The fluid velocity based on mixed element method is post-processed by the convolution with Bramble-Schatz kernel. Convergence analysis shows that the property of superconvergence, originally held for the approximation of velocity, can be retained for the approximation of concentration variable. Compared with the traditional results in references, the constraint conditions between parameters in this paper are improved essentially.     

Design of optical triangulation devices

This paper presents the derivation of the precise relation between the displacement of a light spot on an object's surface and the displacement of its image on the detector in an optical triangulation device, along with applications of the design of triangulation devices. Based on this relation, improved designs of optical triangulation devices, including devices of adjustable configurations, are proposed and discussed.     

Boundary Value Problems of the Theory of Analytic Functions with Displacements

Integral representations are constructed for functions holomorphic in a strip. Using these representations an effective solution of Carleman type problem is given for a strip.     

刚体位移对应变测试的影响

通过运用波前干涉理论,得到了贴片云纹干涉法测圆柱壳的位移与应变公式,分析了刚体位移及曲率对测试结果的影响情况.指出了在对压力容器及管道进行测试时应注意的事项.     

Extension of the Coherent Gradient Sensor (CGS) to the Combined Measurement of In-Plane and Out-of-Plane Displacement Field Gradients

The Coherent Gradient Sensor (CGS) is extended to the optical differentiation of specular, diffracted wave fronts leading to the combined measurement of in- and out-of-plane displacement field gradients. A derivation of the underlying optical interference principles is presented along with an analysis of the effective instrument sensitivity. In order to demonstrate the capabilities of the technique, experimental measurements of crack-tip deformation fields were conducted under various loading conditions corresponding to mode-I, mode-II, and mixed mode near-tip crack fields. The experimental procedures and results of these tests are presented as validation of the technique.     

A semi-automatic method for measuring interferometry fringes: prototype design and first results

A device for automatically obtaining the information contained in holographic interferometry fringes is proposed. The method may be applied to any kind of interferometric fringes. Accuracy has been demonstrated by contrasting the results obtained with our prototype system and those with the single-beam speckle interferometry technique for the measurement of displacements in a plane. The results show good correlation between the two series of measurements.     

Non-contacting laser based displacement measurements from solid objects

This note reports a laser Doppler interferometer for measuring the axial motion of solid targets which have had no prior preparation. Both magnitude and sense of motion are measured to a resolution at least 0.316 μm usinga passive optical system and simple signal processing, making the device relatively cheap to construct. Results indicate that the LDI is capable of good linearity over a substantial range of target amplitudes and has a reasonable degree of immunity from speckle effects.