• Transactions of Materials Processing
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• v.8 no.3
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• pp.271-271
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• 1999

A concentration change during grade transition operation in thin slab casting is investigated through computer simulation and the results are compared with experimental measurements. Fluid flow and mixing patterns in various tundish levers and flow rates were analysed by a three-dimensional mathematical model. Based on the contained results, a simple, efficient and accurate computational model is suggested to predict the concentration profile at the outlet of the tundish. Based on the model, mixing in and below the mold was analyzed considering electromagnetic braking force. The predicted concentration profiles show good agreements with the measured values. It is found that the lower vortices in the mold are suppressed by the electromagnetic field and a plug-like flow region develops, which decreases the intermixing of two different grades of steel and shortens the length of transition region.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.2
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• pp.21-30
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• 1995

In order to save time and efforts in generating finite element meshes in irregular houndaries of domains, it is needed to develop an automatic mesh-generator which can hoth promote the accuracy of solutions and reduce the run-time in operating finite ele- ment models. In this study, the advancing front technique of triangular mesh generation and the transforming technique from triangular meshes to quadrilateral meshes were used to de- velop a computer program for the automatic triangular and quadrilateral meshes in the mixed shape. Furthermore, to enhance the quadrilateral mesh quality, the techniques of Laplancian smoothing and interior mesh modification were employed. The mesh genera- tor was applied to evaluate its applicability to irregular and complex geometries such as Nakdong river bay. In has hoen shown that the automatic mesh generator developed is capable of automatically generating meshes for irreguiar and complex geometries with high qualities of meshes and with the simple input data of arbitrarily specified nodal spacing in bound- aries.

• Journal of Korea Society of Industrial Information Systems
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• v.1 no.1
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• pp.29-62
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• 1996

In this paper, the problem of determining cyclic schedules for a material handling hoist in the printed-circuit-board(PCB) electroplating line is considered. The objective of this research is to determine an optimal simple-cycle schedule of the hoist which in turn maximizes the line throughput rate. Previous approaches to the cyclic hoist scheduling problem are all mathematical programming-based approaches to develop cyclic schedules(Mixed Integer Programming, Linear Programming based Branch and Bound, Branch and Bound Search Method and so on). In this paper, a genetic algorithm-based approach for a single hoist scheduling in the PCB electroplating line is described. Through some experiments for the well known example data and randomly generated data, the proposed algorithm is shown to be more efficient than the previous mathematical programming-based algorithm.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.10
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• pp.795-804
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• 1989

A parallel analog-to digital converter with neuron-like elements is designed and optically implemented. Its operation principle is based on the simultaneous estimation of bit values for a given analog input. The architecture of the proposed analog-to-digital converter is simpler than that of an earlier one designed by the energy minimization technique, and its digital output is independent of the initial state. Mixed binary-to-full binary converters are also designed by using out analog-to-digital converters as basic computing elements. These converters have simple structures and fast conversion times compared with earlier ones.

• Journal of the Korean Ceramic Society
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• v.12 no.3
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• pp.3-7
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• 1975

The usefulness of the domestic shale contained chiastolite as additive were investigated. Crude mixed minerals were separated into shale and chiastolite. Refractory body added simple component or multiple components as additives was obtained when firing at 125$0^{\circ}C$ for each body. Compressive strength, refractories, apparent sp. gr., water absorption, corrosion test by slag, hot linear expansion were measured and X-ray diffraction analysis was observed. As the result of study, refractory body contained separated minerals as additives showed slightly increasing in refractoriness, lowering in sintering effect, the excellent effect for corrosion resistance by acidic slag. With more containing separated minerals, hot linear expansion for the body can be decreased.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.3
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• pp.355-356
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• 2005

The problem of maximizing an OWA aggregation of a group of variables that are interrelated and constrained by a collection of linear inequalities is considered by Yager[Fuzzy Sets and Systems, 81(1996) 89-101]. He obtained how this problem can be modelled as a mixed integer linear programming problem. Recently, Carlsson et al. [Fuzzy Sets and Systems, 139(2003) 543-546] obtained a simple algorithm for exact computation of optimal solutions to a constrained OWA aggregation problem with a single constraint on the sum of all decision variables. In this note, we introduce anew approach to the same problem as Carlsson et al. considered. Indeed, it is a direct consequence of a known result of the linear programming problem.

• Journal of the Korean Ceramic Society
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• v.43 no.4 s.287
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• pp.220-223
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• 2006

BLT nanotubes were synthesized by using simple and convenient method template-wetting process. Porous alumina membranes were prepared by 2 step anodic oxidation as the template. To improve wetting properties and make low surface energy, BLT solution was mixed with polymer. Polymer was removed completely during annealing. After completely etching the template in 30 wt% KOH solution, we demonstrate that BLT nanotubes with a diameter of 200 nm can be fabricated. Grain growth process of BLT nanotubes during baking, and furnace annealing was examined by FE-SEM and XRD.

• Bulletin of the Korean Chemical Society
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• v.24 no.3
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• pp.291-294
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• 2003

A highly interferent-resistive membrane, poly-5-amino-1-naphthol (poly-5A1N), underlied beneath enzymeembedded poly-1,3-phenylendiamine (poly-m-PD) network for miniturized continuous monitoring glucose sensors. The enzyme layer was prepared from a mixed solution of glucose oxidase (GOx) and m-PD monomer by simple electrolysis. The mass change of poly-5A1N was monitored by electrochemical quartz crystal microbalance (EQCM) in situ and the corresponding thickness was measured. Successive electropolymerization of poly-5A1N and poly-m-PD create a several tens nm-thick bilayer showing excellent selectivity for $H_2O_2$ and low activity loss of immobilized enzymes.

• Journal of Life Science
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• v.18 no.1
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• pp.91-95
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• 2008

In human, sympathetic nerve blocks with local anesthetics are widely used to treat a variety of diseases in the innervating regions. However, its procedure in dogs is difficult to approach and process repeatedly because of anatomically location. Therefore, this study was designed to develop a new technique of sympathetic nerve block in beagle dogs. Fifteen healthy beagle dogs, which did not show any neurologic abnormalities and disease, were used for the study. Radiograghs were taken after injected radiopaque material mixed with 2% lidocaine at the cranial cervical ganglion and injected methylene blue using the same percutaneous technique to verify the reliability of this newly developed technique. The successful block rate of the cranial cervical ganglion block was present in 80% of all dogs and the stained cranial cervical ganglions were shown in all dogs. The results show that this new technique of the cranial cervical ganglion block is a reliable and simple method that can be used for clinical studies in dogs.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.851-852
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• 2006

The introduction of ceramic particulate into metallic powder will unavoidably lower the compressibility and formability of the mixed powder. In this study, warm compaction, which is a simple and low cost technique to produce high density PM parts, was introduced in preparing composite. The aim of this paper is to prepare the warm compacted NbC particulate reinforced Fe-based composite, then study its tribological behavior and application in the valve-guide cup. A 15 wt.% NbC reinforced iron-based composite was prepared. It possesses a relative density of 98%, a tensile strength of 515 MPa, a hardness of HRC 58 and a remarkable tribological behavior.