摘要:

The method of displacement discontinuity is applied in this paper to study the propagation of a vertical hydraulic fracture in a porous medium. The infiltration of fracturing fluid into a rock medium and its effect on the size of the hydraulically induced fracture are examined in this study. The equation for fluid motion inside the fracture is derived from the conservation of the fluid mass, and the equation relating the fluid pressure and the fracture opening is derived from the overall deformation of the porous rock medium. The finite element method is incorporated with the method of displacement discontinuity to obtain the solutions of the problem.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677036

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Based on the seismicity and tectonics of Taiwan area, a set of potential earthquake sources is identified. Using available attenuation laws and fault‐rupture model, the individual influences of potential sources are integrated into the probability distribution of maximum annual intensity and peak acceleration. The results are presented in the form of seismic risk maps for a 475‐year return period. Based on the result of this study, it concludes that the seismic hazard potential for the central region is moderate, but it is high for east‐coast region.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677037

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The presence of discontinuity in the geological media has long been recognized as an important factor influencing the mechanical behavior of the media. This paper proposed a versatile constitutive law that can model an assemblage of intact rock blocks separated by cleavage, bedding planes, joints, or other types of structural weak planes. The constitutive law is capable of modelling any number of joint sets with arbitrary orientations. Applicability of the model are evaluated by comparing the predicted results with existing model predictions. The effects of joint numbers, and joint orientations are also discussed.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677038

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In the present study, the instantaneous stiffness matrix of an R/C column with effects of shear deformation and axial load being considered has been constructed by using finite segment method. In addition, the effect of bond slip is considered by applying the concept of semi‐rigid joint to modify the stiffness matrix of the column. Pacoima Dam earthquake data is used as excitation in computation of R/C columns subjected to 1D or 2D severe earthquakes. It is found that the displacement and strain responses of columns to 2D excitations are greater than those of columns to 1D excitation. The effect of bond slip at lower end of column is obvious for the case of columns to 2D excitations.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677039

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In the present study, In1–xGaxAsyP1–y/InP double heterostructure (DH) laser diodes with emission wavelength of 1.3μmat room temperature were fabricated on (100) oriented InP subtrates. The properties of active layer were determined by EPMA, optical transmission and PL measurement. The electrical and optical properties were measured and discussed. Lasers fabricated from the heterostructure exhibited good electroluminescence. A broad area laser with active region thickness of 0.35μm has a threshold current density as low as 1.52kA/cm2. The emission spectra just above threshold indicated a dominant peak near 1.29μm. A typical value of the pulsed threshold current density of stripe lasers was 5 kA/cm2. The series resistance as low as 2Owas obtained for these diodes. With proper heat sink, CW operation of these laser diodes can be obtained.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677040

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This paper presents a new recursive method for sensitivity calculations which is suitable for computer aided analysis and design of nonlinear DC networks. Rather than the adjoint networks, a direct method which is easily understood is used; the nonlinear diakoptics based on the generalized orthogonal network is applied to the direct method to yield an efficient method for the sensitivity calculation of nonlinear DC network. This new method can handle networks which are too large to be handled by the direct method or the adjoint networks approach alone. It is shown that the formulas for computing the sensitivities of all the response variables of a network with respect to the variation of a single parameter are easily derived, and the computations can be carried out very efficiently. However, the problem of computing the sensitivities of a single response variable with respect to the variations of several parameters can be derived using only matrix manipulations. Thus, the algorithms provide a new and efficient method for computer aided sensitivity analysis of nonlinear DC networks.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677041

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The adaptive model following bang‐bang control (BB‐MFC) and variable‐structure model following control (VSS‐MFC) have the advantage of no tracking error. However, they are impractical in mechanical application. They will excite the mechanical resonance due to the high‐frequency switching of control signal. Therefore, we use the “modified VSS”. By theoretical analysis, simulations and experiments, the “modified, VSS” effectively modifies the control signal. There was no mechanical resonance in the experiments of DC motor position control.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677042

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A hardware system described in this paper is a high‐speed parallel machine which is called multi‐function parallel processor (MFPP). All 3×3 maskable parallel algorithms concerned with the binary image processing can be implemented on MFPP such as smoothing, contouring, erosion, dilation, thinning, feature extraction, and so forth. A prototype of MFPP has been designed to work at 5 MHz clock rate and operated simultaneously with four processing units to achieve the desired speed. The processing speed of the prototype is about 600 times faster than that of a 16‐bit microcomputer at the same clock base. It takes about 27 msec to carry out a 3×3 masking operation onto a binary image of 256×256 pixels.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677043

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The generalized Sturm‐Liouville eigenvalue problems with singularity at origin are investigated by applying an approximation method in a Hilbert space. The variable coefficients in the problem and the solution are approximated by a suitable linear independent basis, and then the symmetry property of the inner product is used to develop a backward recursive formula. Two examples are given to demonstrate that the computation is straightforward.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677044

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A shadow deposited lens‐like waveguide usingrfreactively sputtered Ta2O5films onto Corning 7059 glass substrate has been fabricated. Laser beam can be successfully taper‐coupled into the waveguide from the backplate of the substrate. The focusing properties of the fabricated waveguide were observed from the photographs of multiple exposure of the laser beam ray trajectories. The effective index profiles of the deposited waveguide can be approximated by thesech(gx) function. Calculated results of the distances between focal points from thesech(gx) index profiles can fit the experimental data very well with a deviation of less than 1.8%.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677045

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor