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11.
Polymer supported dichlorophosphate (PEG-OPOCl2) is an efficient green catalyst for the electrophilic substitution reaction of indole with aromatic aldehydes, in neat condition, to afford an excellent yield of bis(indolyl) methanes with short reaction time, at room temperature. The synthesized compounds and their anti-cancer activity are evaluated.  相似文献   
12.
We propose a class of finite state systems of synchronizing distributed processes, where processes make assumptions at local states about the state of other processes in the system. This constrains the global states of the system to those where assumptions made by a process about another are compatible with the commitments offered by the other at that state. We model examples like reliable bit transmission and sequence transmission protocols in this framework and discuss how assumption-commitment structure facilitates compositional design of such protocols. We prove a decomposition theorem which states that every protocol specified globally as a finite state system can be decomposed into such an assumption compatible system. We also present a syntactic characterization of this class using top level parallel composition. The main results here were first reported in an earlier paper (Mohalik & Ramanujam 1998). We thank the anonymous reviewers for detailed comments that helped to improve the presentation  相似文献   
13.
Dielectric properties of the inflated and deflated fceline lung in vivo were investigated at frequencies from 10 kHz to 100 MHz. A computer-controlled network analyzer and a multiring capacitive sensor were employed. It was found that in the frequency range investigated, both the dielectric constant and the conductivity of the deflated lung were higher than those of the inflated one. The analysis of the experimental data was performed using two approaches: the loss-tangent method and the curve-fitting computer program called STEPIT. It was found that in the middle band of frequencies for both inflated and deflated states of the lung, the dielectric response mainly reflects the membrane polarization of the capillary erythrocytes with possible contributions of other components, e.g., the pulmonary microphages. The dielectric relaxation time for the capillary erythrocytes in the lung is similar to that for the packed cells, which is much longer than for the erythrocytes at physiological concentrations. The dielectric parameters at low frequencies obtained using the STEPIT program differ significantly between the inflated and deflated lung. The observed dielectric data reflect at least two overlapping dispersions: of lung capillary erythrocytes and of cellular structures forming the alveoli.  相似文献   
14.
Engineering changes to products aim to correct design faults, exploit new market opportunities, improve overall product performance, or reduce production costs. These changes are thus considered as opportunities to stay competitive in the market place and companies strive to implement them in their products at the lowest possible costs. Such engineering changes in a collaborative environment require the original equipment manufacturer to work together with suppliers for designing, manufacturing, and marketing a product profitably. Simulation of an engineering change management process provides an understanding of important factors affecting the engineering change management process and helps in identifying any critical components of the entire process. In this research, system dynamics models have been developed to study the complex interrelationships among various members in a collaborative supply chain to achieve effective and efficient engineering change management processes. To address the complexity of the models, several standard templates have been developed and used.  相似文献   
15.
A formal semantics for an active functional DBPL   总被引:1,自引:1,他引:0  
We describe how the functional database programming language PFL is extended with an active component without compromising either its declarative semantics or its syntax. We give a formal specification of the active component using PFL itself, including event specification and detection, parameter-binding, reaction scheduling and abort handling. We describe how a user-specified function can be cast as a primitive event, and discuss the expressiveness of events and the optimisation of event detection.  相似文献   
16.
17.
To make an appropriate choice of linear model for the development of real-time control of robot manipulators, four direct linearization schemes have been studied here on the basis of computation and accuracy. Accuracy is assured in the state linearization method, whereas the rate linearization method leads to a satisfactory trade-off between computational effort and accuracy. In the case of high-velocity motions, a combination of state and rate linearization is proposed.  相似文献   
18.
The use of bone grafts is the basis of all craniofacial surgery. Bone grafts are used to stabilize the open segments, expand the patient's structural boundaries, and fill defects created by trauma or congenital malformations. Bone grafts are harvested from local or distant sites as indicated. Biomaterial implants are used as bone substitutes when it is not possible to use bone grafts.  相似文献   
19.
In recent years the development of superfast computer systems with very high speeds and throughputs is growing rapidly with the tremendous advances in computer hardware technology. At the same time the software costs are becoming more dominant in the total system costs. Considering these aspects some of the most important considerations in the development and maintenance of computer software in cost-effective reliable software engineering and development are discussed. For the success of software managers, effective management and software engineering and development techniques have been presented to reduce the software life-cycle costs and to improve the efficiency of reliable software management in practice. An extensive survey of cost-effective reliable software engineering and development techniques, and the foundation upon which to establish the development and maintenance environment for future software systems are also provided.  相似文献   
20.
BMP3 and TGF beta 1 were found to induce opposite effects on human bone marrow stromal cells both in cell proliferation and cell differentiation and on calcium deposition onto the extracellular matrix. Moreover, BMP3 may exert, in part, the inhibitory effect of TGF beta 1 through decreasing the affinity of TGF-beta for its receptors which are now identified in these human bone cells.  相似文献   
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