ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677501

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper presents a general method for designing a phase digitizer incorporating a D/A converter. Systematic derivation of design method as well as performance analysis are given forN‐bit phase digitizer, and implementations of the 3‐bit and 4‐bit phase digitizers are provided. In addition, the design method includes two different design models.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677502

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper presents a robust variable structure system control algorithm for a multivariable affine nonlinear system. It will be shown that if the considered system has aleft‐invertiblenominal part and satisfies thegeneralized matching restriction, then the output of the controlled system will track the desired trajectory asymptotically. Furthermore, thelinear model matching problemis also investigated in this paper. It is shown that under suitable conditions, the controlled system will have the same input‐output behavior as the prescribed linear model. Simulation results are included to demonstrate the power of the design procedure.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677503

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We design high‐efficiency, small‐volume power supplies by means of a series resonant converter (SRC) and a parallel resonant converter (PRC). The small‐signal model in the discontinuous conduction mode (DCM) for each converter is derived so that it can be used for frequency‐domain analysis and transient analysis for step load change. The closed‐loop response for each converter exhibits very wide bandwidth and provides disturbance rejection.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677504

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The nature of the flow past a circular cylinder has been a classical problem, raising many questions concerning the various wake phenomena that have been observed. This study focused on the critical Reynolds number for the onset of the recirculation region for a flow restricted in a channel. The influence of the bounded walls is examined. The trend is that larger critical Reynolds numbers are accomplished with larger values of blockage ratio (defined as the ratio of cylinder diameter to the channel width). Furthermore, as the blockage ratio tends to zero, the trend seems to imply that the critical Reynolds number approaches the experimental value for flows in an unbounded domain.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677505

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Two objectives are reached in this paper. First, we find the set of dynamic covariance controllers such that the Root‐Mean‐Squared (RMS) value (performance requirements) for each system state of the nominal bilinear stochastic system is less than or equal to some prespecified values set by these controllers. Secondly, when modeling errors are present in the plant parameters, we seek the set of admissible perturbations such that the RMS value for each state of the uncertain closed‐loop system will still be less than or equal to some prespecified values.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677506

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A mixed direct method taking the advantages of both the potential energy boundary surface (PEBS) method and the extended equal area criterion (EEAC) method for transient stability analysis of multimachine power systems with detailed models is presented. The mixed direct method first computes the approximate critically cleared trajectory using the critical clearing time which is fast estimated by the EEAC method. Then, the critical energy is evaluated along this trajectory by the PEBS method to access the transient stability. The proposed method overcomes the problem of the variance of potential energy at the boundary crossing and remedies the effect due to the fast dynamics contained in the detailed model. The fast dynamics destroys the assumption that a sustained fault can be used to approximate the critically cleared trajectory and its corresponding critical energy. Moreover, an efficient classifying criterion based on an interaction index for simplifying the power system modeling with reasonable accuracy is also presented. The criterion is incorporated into the mixed direct method to speed up the computation in transient stability analysis. Finally, investigations are carried out on Taipower system, which is the unique power system in Taiwan, to illustrate the application of the proposed method to transient stability assessment.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677507

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An analysis on the strength of reinforced concrete slender columns subjected to biaxial loads is presented. The behavior of pin‐ended square and rectangular columns under a braced condition was studied. Lateral deflections and secondary moments were evaluated iteratively using non‐linear moment‐thrust‐curvature (M‐P‐F) relationships. Results have been verified with published data. The moment magnification factors were also compared to those calculated using ACI Code approximate method and the agreement is good for most practical cases. Parametric studies reveal that under the same steel ratio, gross cross sectional area and length, square columns lead to better capacities than rectangular columns forMx/My<2.0. The advantage of using a rectangular long column could only be achieved whenMx/My>2.0

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677508

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This study is aimed at examining the behavior of the beam to interior box column connection. Cruciform type test setups are selected with the column under constant gravity load while both beams under gradually increased cyclic loading in opposite directions to simulate earthquake load. The tearing strength of the column plate by the transmitted out‐of‐plane load from the beam web is analyzed by yield line theory. A simplified method is proposed to establish the relationship between the thickness of beam web and column plate. A series of experimental studies are also conducted to examine the effect of a diaphragm plate on the transmission of applied force from beam flanges. Based on the results of this study, suggestions are made for the design and construction of beam to box column connections to achieve better strength and ductility.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677509

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The addition of chromium acetylacetonate in N, N, N’, N’, tetraglycidyl diaminodiphenyl methane/diaminodiphenyl sulfone/boron trifluoride‐monoethylene amine epoxy formulations for manufacturing unidirectional Gr/Ep laminates accelerated the curing reaction and increased the viscosity of resin during lamination. Differential scanning calorimetric and infrared spectroscopic results indicated that Cr(acac)3acted like a cocatalyst with BF3MEA during curing. As the laminates were cured, the one incorporating 1 mol% Cr(acac)3exhibited the highest GICfracture toughness, flexural strength, and transverse tensile strength. The increased mechanical strength of the Gr/Ep laminates was due to the fact that the cohesive strength of the epoxy matrix was increased by the incorporated Cr(acac)3.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677510

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor