ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677709

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The effect of various gate insulators on the electrical properties of the amorphous silicon thin film transistors (TFTs) has been investigated. When the silicon nitride is used as the gate insulator, the on/off current ratio of the TFT is found to exceed 106and the subthreshold swing is 0.4 V/decade. The highest field‐effect mobility achieved is about 0.42 cm2/V‐sec. A channel thickness of 50 nm is found to be appropriate to achieve good performance and the source/gate contact overlap of 0.5μm eliminates the source resistance problem. When the electron gun evaporated silicon dioxide (SiO1.68) is used as the insulator, the highest field‐effect mobility of TFT in the saturation region of the IDSversus VDScurve is 5.1 cm2/‐sec. Actually, the electron drift velocity has saturated at 1.7 × 104cm/sec, this is the first report of the electron saturation velocity in amorphous silicon alloy. The on/off current ratio exceeds 105and the subthreshold swing is ranged from 0.25 to 0.5 V/decade.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677710

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The nonlinear equation describing the steady state of a nonlinear anisotropic diffusion process can be transformed to a special type of linear partial differential equation using the Kirchhoff transformation together with the hodograph transformation. The method of separation of variables is employed to obtain exact solutions. A solution with a domain bounded by two ellipses is studied in detail for the materials which have a linear conductivity function in one direction and a constant conductivity function in the other direction. Comparison of the adopted approach with the similarity reduction approach is also presented, though the obtained results cannot be easily found via the latter approach. A special case is found in which the transformed linear equation can be reduced further to the Laplace equation.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677711

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The paper proposes and evaluates a protocol which combines the ideas of demand assignment and movable boundary for integrating voice and data traffic in a high speed common channel. Each multiplexer serves a group of voice users plus a data user The common channel is shared by a number of groups of multiplexers using distributive demand assigned TDMA. Within each group time slots are shared between voice and data users through movable boundary Since voice has real‐time constraint, it is given higher priority in the use of channel resource. Blocked calls are assumed lost. In this paper, mathemetical expressions of several key performance measures are derived. Numerical examples are used to demonstrate the performance of this protocol and computer simulations are also conducted to verify the results.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677712

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A real time Petri net (RTPN) model is proposed to model the task specification of a real time system in terms of events, actions, states, and temporal constraints. The basic operations of a RTPN include executable transition identification, marking updating, temporal constraint check, and shared input/output calculation. These are time‐consuming processes on whatever computers they are executed. A hardware‐implementable execution model is proposed to improve their performance. Detailed hardware designs of the event and state matching modules in the execution model are described. They employ an associative technique to provide massive parallelism needed in the modules. Moreover, the time complexities of the event and state matching modules are constant, which allows us to better control or predict the behavior of a real time task — a very important feature in a real‐time system.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677713

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Forces acting on a sphere rolling down an inclined smooth or rough channel include submerged weight of the sphere, fluid drag, fluid lift, and rolling resistance from the channel bed. When the acting forces are in equilibrium, the sphere rolls down the inclined channel with a terminal velocity. The steady movements of such a sphere rolling down smooth and rough channel beds with the terminal velocity are studied through laboratory experiments and a simplified theoretical analysis. A method is proposed to evaluate the rolling resistance that consists of collision and friction parts of resistance. The coefficients of rolling resistance and the drag coefficients are determined by regression analysis with experimental data. The relationships of the drag coefficients and the Reynolds numbers for a sphere rolling over smooth and rough channel beds are also obtained. It is found that at the same Reynolds number, the drag coefficient for a sphere rolling down a rough bed is larger than that for a sphere down a smooth one, and that both are much larger than that of a sphere in the free fall.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677714

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper, a dynamic programming (DP) algorithm is proposed to compute themaximum a posteriori probability(MAP) estimate of the random location of multiple sources by passive sensor array. Based on the principle of optimality, the multivariate MAP decision problem can be transformed into a multistage one‐dimensional maximization problem. By a recursive computation and backward optimum searching technique, the MAP solution can be obtained. The computational complexity is much less than that of the direct MAP searching method, especially when the number of sensors and/or the number of sources is large. In addition, the DP computation technique is equally applicable both in the case of correlated sources and the case of uncorrelated sources.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677715

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The SKT reliability is the probability that a source can send communication to a specified set of terminalsKinVin a probabilistic digraphD= (V, E). “The most vital edge” is the edge whose deletion yields the largest decrease in the SKT reliability. A digraph is a basically‐series‐parallel(BSP) directed graph if its underlying undirected graph is series‐parallel. In this paper, we propose a tree‐like structure and present an optimal algorithm with linear time complexity for finding the most vital edge with respect to SKT reliability in BSP digraphs.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677716

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In view of the potential advantages of using field‐emission cathodes as electron sources, a renewed interest in advanced IC technology utilizing silicon‐based coldcathode microelectronics is emerging. However, some etching results concerning emitter formation are still unknown. This paper presents a study of emitter formation by various wet and dry etching methods. Some geometrical models are given for the analysis of anisotropic etching results. The emission features from different emitter arrays are also given for comparison. Through understanding the emission characteristics of various emitter arrays, a novel design for Field‐Emission Flat Panel Display is proposed.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677717

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The extraction of phenol from an aqueous solution using sulfuric acid salts of trioctylamine (TOA salts) was carried out. Trioctylamine (TOA) dissolved in diisopropyl ether (DIPE) (or 1‐octanol, cyclohex‐ane, benzene and kerosene) was evaluated for extraction of phenol at various volume ratios of organic phase to aqueous phase at varied temperatures. The equilibrium distribution coefficient (KD) for the extraction of phenol with TOA salts in those diluents was measured. Phenol is extracted by a physical distribution with pure diluent alone and through the interaction between TOA and phenol. The latter was quantitatively interpreted according to a reaction scheme in which adducts of several kinds were composed of trioctylamine and phenol. The TOA salts have a significantly greater extraction capability for phenol than TOA itself. The reaction of phenol and hydroxide ion to form phenoxide ion is used to explain the small extraction of solute at high pH. A simple mathematical model was derived to account for the effect of the volume ratio of organic phase to aqueous phase on the value ofKD,and for the effect of the initial concentration of phenol on the value ofKD.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677718

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor