摘要:

In the present study, the synthesis of allyl phenyl ether by reacting sodium phenoxide and allyl bromide using PEGs as phase transfer catalysts either in a homogeneous phase or in a two‐phase reaction was studied. The reaction in a homogeneous phase was carried out using EtOH as the solvent and the reaction in a two‐phase was carried out using aprotic solvents, such as dichloromethane, chlorobenzene, ethyl ether, cyclohexane and n‐decane. In the homogeneous phase reaction, the effects of the molecular weights of PEGs on the initial reaction rate were investigated in detail. The aprotic properties of the PEGs were used to explain the variation in experimental results due to the use of different molecular weight PEGs. The reactivity of the reaction, which was influenced by the organic solvents in a two‐phase reaction, was also examined. The effects of the polarity of the solvents, the solubility of sodium phenoxide in the organic phase and the viscosity of the solution on the two‐phase reaction were employed to explain the experimental results satisfactorily.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677541

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Symmetrically simple test patterns for parallel testing of row/column pattern‐sensitive faults in RAMs are proposed in this paper. Based on the concept of the maximum leakage current among the RAM cells, the worst case testing becomes the critically efficient method for RAM testing. Due to the simplicity of generating test patterns, we can implement a BIST RAM with test procedures stored in a microprogram ROM to reduce the cost and time of testing. The test complexity of row/column pattern‐sensitive faults is reduced toO(N) in anNbits RAM as compared withO(N3/2) of [1].

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677542

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In this paper, we present a new scheme called the maximum log‐likelihood sum (MLSUM) algorithm to simultaneously determine the number of closely‐spaced sources and their locations by uniform linear sensor arrays. Based on the principle of the maximum likelihood (ML) estimator and a newly proposed orthogonal‐projection decomposition technique, the multivariate log‐likelihood maximization problem is transformed into a multistage one‐dimensional log‐likelihood‐sum maximization problem. The global‐optimum solution of the approximated ML localization is obtained by simply maximizing the single one‐dimensional log‐likelihood function. This algorithm is applicable to coherent sources as well as incoherent sources. The computer simulations show that the MLSUM algorithm is much superior to the MUSIC when the element SNR is low and/or the number of snapshots is small.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677543

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Due to the varying time and the complexity of the commercial telecommunication network configuration, routing of the communication traffic becomes very important for telecommunication systems. No one can keep in mind all the complex routing plans used in networks, so it is hard to quickly take proper actions while the switching node is being blocked.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677544

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A design method to achieve robust stability and performance criteria for discrete two‐time‐scale systems controlled by low‐order observer‐based compensators is proposed. Sufficient conditions for stability and performance robustness are established by an easy extension of the small gain theorem. The theoretical analysis is illustrated by a numerical example.

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677545

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1993.9677530

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor