Preparation of patterned SiC and SiCN microstructures

With the development of modern science and technology, the importance of small structures or microstructures (such as the fluidic nanostructure or microreactor[1], the in- tegrate circuit in microelectronics[2], the factory in a chip[3,4], etc.) has been incarnated day by day in the fields of microelectronics, micro-optical systems, microanalytical sys- tems, microelectromechanical systems and cytobiology. And the fabrication technique (microfabrication) of the small structures has become the h…     

Optimal control of economic growth with application to Korean economy

This paper is concerned with the application of optimal control theory to the dual growth of the Korean economy. A closed two sector economic growth model is formulated by dividing the economy into agriculture and non-agriculture in order to represent the transitional phenomena between the two sectors. Taking capital and saving as state and control variables, respectively, the model governing the economic growth becomes a non-linear simultaneous differential equations with coupling terms of state and control variables. Assuming the Cobb-Douglas production function and the exponential form of the social welfare function, the necessary and sufficient conditions of the optimal control have been derived for the case of finite planning horizon by using the Pontryagin's maximum principle. Since deriving the optimal trajectories of state and control variables analytically is impossible, a numerical procedure based on the variation of extremals is used to obtain the optimal paths of the aggregate investment and consumption of the Korean economy.     

CONFIGURING BOTH BACKBONE AND LOGICAL NETWORKS OF A RECONFIGURABLE NETWORK WITH LINK FAILURES ALLOWED

This paper considers a problem of configuring both backbone and logical networks in a reconfigurable circuit-switched network where links are subject to failures. The objective is to design feasible backbone and logical networks at least cost where the cost includes backbone link capacity expansion cost, lost-call traffic penalty, and hop cost (nodal processing cost). The problem is formulated as a zero-one non-linear mixed integer programming problem, for which a solution procedure is developed by use of a Lagrangean relaxation technique and heuristic methods exploited for improving the lower and upper bounds of any intermediate solution. The solution procedure is tested for its effectiveness with various numerical examples.     

Improvement of the Functionalities of Soy Protein Isolate through Chemical Phosphorylation

A method of chemical phosphorylation was developed to modify soy protein so as to improve its functional properties. The reaction was carried out by incubating soy protein isolate and cyclic sodium trimetaphosphate in an aqueous solution at pH 11.5 and 35°C for about 3 hours. The reactions ensued were the phosphoesterification of serine residues and the phosphoramidation of lysine residues in soy protein. The phosphorylated soy protein isolate prepared there-from exhibited much improved functional properties in terms of aqueous solubility, water-holding capacity, emulsifiability and whippability. The nutritive bioavailability of soy protein isolate was not impaired by phosphorylation.     

A Study of the Heat Transfer Characteristics of an FC-72(C6F14) Two-Phase Closed Thermosyphon with Helical Grooves on the Inner Surface

This study is a fundamental work performed to obtain basic information about designing two-phase closed thermosyphons with a working fluid of FC-72 (C₆F₁₄). FC-72 is a kind of alternative refrigerant designed to be chemically safe and more environmentally friendly than any other conventional CFC refrigerants.

To obtain experimental data on operational performances of a FC-72 two-phase closed thermosyphon, an experimental model was designed and manufactured with a micro fin groove copper tube with an outside diameter of 22.2 mm for its container, on which a series of operational performance tests were conducted. Its maximum capacity of heat transport rate was designed to be about 300–400 W. The focus was given to investigate the effects of such parameters as micro fin grooves and fill charge ratios on operational performances of the FC-72 two-phase closed thermosyphon. The experimental data on phase change heat transfer coefficients and heat transport limitations were compared with some corresponding correlations, and a couple of measures that would help to predict operational performances were suggested with some physical explanations.