• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2139-2144
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• 2003

In steel-making processes of iron and steel industry, the purity and quality of steel can be dependent on the amount of CO contained in the molten metal. Recently, the supersonic oxygen jet is being applied to the molten metal in the electric furnace and thus reduces the CO amount through the chemical reactions between the oxygen jet and molten metal, leading to a better quality of steel. In this application, the supersonic oxygen jet is limited in the distance over which the supersonic velocity is maintained. In order to get longer supersonic jet propagation into the molten metal, a supersonic coherent jet is suggested as one of the alternatives which are applicable to the electric furnace system. It has a flame around the conventional supersonic jet and thus the entrainment effect of the surrounding gas into the supersonic jet is reduced, leading to a longer propagation of the supersonic jet. The objective of the present study is to investigate the supersonic coherent jet flow. A computational study is carried out to solve the compressible, axisymmetric Navier-Stokes equations. The computational results of the supersonic coherent jet are compared with the conventional supersonic jet.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.514-519
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• 2001

Converter has been slag produced 10 million tons per year in Japan. It is a steel making by product produced in the same way as the blast-furnace slag. Though blast-furnace slag is being used effectively as a concrete admixture, the converter stag has never been used effectively because of the expansion action of contained free lime and iron oxide. This is an important environmental problem in the steel industry. Beta-2CaOSiO$_2$(beta-C$_2$S) is contained 40 percent in converter slag, therefore it is very promising as a concrete admixture. We proposed an accelerated aging processes capable of stabilizing the converter slag in a short time. The converter slag is dipped into alkali aqueous solution after heating at low temperature. It was subsequently ground to a grain size of 75 ${\mu}{\textrm}{m}$ , inner 30 percent of OPC. The properties of mortar and concrete using the blended cement were determined. As a result, it has become apparent that the expansion was reduced and long term compressive strength was increased while that at early ages was not so remarkable. The hydration exotherm rate was lower than that of the OPC.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.490-495
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• 2003

In steel-making process of iron and steel industry, the purity and quality of steel can be dependent on the amount of CO contained in the molten metal. Recently, the supersonic oxygen jet is being applied to the molten metal in the electric furnace and thus reduces the CO amount through the chemical reactions between the oxygen jet and molten metal, leading to a better quality of steel. In this application, the supersonic oxygen jet is limited in the distance over which the supersonic velocity is maintained. In order to get longer supersonic jet propagation into the molten metal, a supersonic coherent jet is suggested as one of the alternatives which are applicable to the electric furnace system. It has a flame around the conventional supersonic jet and thus the entrainment effect of the surrounding gas into the supersonic jet is reduced, leading to a longer propagation of the supersonic jet. In this regard, gasdynamics mechanism about why the combustion phenomenon surrounding the supersonic jet causes the jet core length to be longer is not yet clarified. The present study investigates the major characteristics of the supersonic coherent jet, compared with the conventional supersonic jet. A computational study is carried out to solve the compressible, axisymmetric Navier-Stokes equations. The computational results of the supersonic coherent jet are compared with the conventional supersonic jets.

• 한국식품위생안전성학회지
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• 제14권1호
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• pp.27-33
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• 1999

Phytic acid, making up 1~5% of the composition of many plant seeds and cereals, is known to form iron-chelates and inhibit lipid peroxidation. Thiobarbituric acid reactive substances (TBARS), as an indication of lipid peroxidation, were measured in beef round, chicken breast, pork loin, and halibut muscle after the meats were stored for 0, 1, 3, 5, and 7 days at various temperatures [frozen (~2$0^{\circ}C$), refrigerator (4$^{\circ}C$), and room temperature ($25^{\circ}C$)]. Phytic acid effectively inhibited lipid peroxidation in beef round, chicken breast, halibut, and pork loin muscle (p<0.05). The inhibitory effect of phytic acid was dependent on concentration, storage time, and temperature. At frozen temperature, the inhibitory effect of phytic acid was minimal, whereas at room temperature, the inhibitory effect of phytic acid was maximal, probably due to the variation of the control TBARS values. At the concentration of 10 mM, phytic acid completely inhibited lipid peroxidation in all the muscle foods by maintaining TBARS values close to the level of the controls, regardless of storage time or temperature (p<0.05). The rate of lipid peroxidation was the highest in beef round muscle, although they had a close TBARS value at 0 day. Addition of phytic acid to lipid-containing foods such as meats, fish meal pastes, and canned seafoods may prevent lipid peroxidation, resulting in improvement of the sensory quality of many foods and prolonged shelf-life.

• 한국주조공학회지
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• 제23권5호
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• pp.257-267
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• 2003

In early solidification during the continuous casting of steel slabs, the formation of oscillation marks on the surface of slabs was mainly affected by carbon contents and casting conditions. The control of oscillation mark is required for the HCR(Hot Charged Rolling) process because the deep oscillation marks seriously deteriorate the surface qualities of steel slabs. The metallographic study has revealed that the oscillation mark can be classified principally according to the presence or absence of a small 'subsurface hook' and the depth of the oscillation marks in the subsurface structure at the basis of individual oscillation marks. The subsurface hook of oscillation marks was either straight or curved. When the amount of overflow was small and the subsurface hook was formed in the top of oscillation marks, the subsurface hook was straight and the oscillation mark was shallow. The oscillation marks without subsurface hook have small early solidification shell and were formed wide. The actual negative strip time$(t_N)$ was changed by the effect of meniscus level fluctuation Therefore irregular early solidification shell and oscillation mark were formed.

• 한국초전도ㆍ저온공학회논문지
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• 제16권3호
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• pp.4-6
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• 2014

Among Fe-based superconductors, potassium doped $BaFe_2As_2$ is favorable for applications because of its relatively high transition temperature and low anisotropy. To study the superconducting properties and the applicable aspects, high quality thin films of potassium doped $BaFe_2As_2$ should be fabricate. However, the high volatility of potassium makes it difficult to fabricate thin films of this compound. In this paper, we discuss the details of the experimental conditions used to fabricate $Ba_{1-x}K_xFe_2As_2$ films by ex situ PLD method. In the first set of samples, barium ratio in the target was controlled to make films with various potassium doping rate. However, in the second set of samples, the amount of potassium was controlled to find out optimal conditions for making high quality $Ba_{1-x}K_xFe_2As_2$ films.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.831-839
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• 2009

An interlocking equipment of railway signalling systems is manufactured with electrical devices and electrical interlocking equipment has been substituted for existing interlock equipment(relay sequential logic type). But interlock conditions are still generated from rail diagram and used to make Interlock Table manually. In order to make EIS(Electrical Interlock System) operate, we should write interlock data which is made from interlock table. But, as the station is larger and more complicated, handwork may becomes a very tediou work and makes more mistakes. Therefore the development of CAD system for Interlocking System is very significant, if CAD can reduce the mistakes from handwork and help the configuring the interlocking system. In this paper, we first arrange some rules which can be used to extract route information automatically from rail diagram and interlocking rules. And then we propose "Search-And-Rollback" algorithm to extract route information and individual interlocking rules. The proposed algorithm is implemented and tested through the signal design process of the Hyundai-Steel private railway to carry melted pig iron from the blast furnace to the steel-making workshop. some cases. It shows that CAD for Interlocking system is very helpful in time saving aspect and system reliability.

• 한국조리학회지
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• 제4권
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• pp.147-166
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• 1998

Following the developing tendency of the food service industry, people are showing a high interest in cooking and the number of applicant trying to learn how to cook is increasing gradually. In this research, we have concluded that developing a menu, we are to standardize its cost accounting correctly so as to reduce problems which can occur during the process to commercialize food. We have to research on the quality of food changing so fast and to develop proper food to suit both the oriental and occidental taste. Since fresh ingredients such as olive oil which has much unsaturated fatty acid, tomato, and fish etc. is usually used in making Italian food, especially the moderns love it very much. The reason is that eating fatty food such as meat and fish with tomato, we can digest it well in our stomach. Tomato play an important role to neutralize the effects of acid food. It has Vitamin B1 dissolving fat, rutin strengthening capillary vessels and controlling high blood pressure, amino acid developing mental activity, iron essential to blood formation, and calcium etc. These ingredients play important roles to control geriatric diseases. The new style of the propensity to consume in the class of new generation and new family, the trend towards the nuclear family, and the rapid expansion of aging have influences on westernizing diet and on spreading new sense of values such as rapidness, convenience, cleanliness, and simplicity for diet. Following the change of the times, the food service industry will be developed more and more.

• 한국건축시공학회지
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• 제12권5호
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• pp.478-489
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• 2012

Each year, about four million tons of steel slag, a by-product produced during the manufacture of steel by refining pig iron in the converter furnace, is generated. It is difficult to recycle this steel slag as aggregate for concrete because the reaction with water and free-CaO in steel slag results in a volume expansion that leads to cracking. However, the steel slag used in this study is atomized using an air-jet method, which rapidly changes the melting substance at high temperature into a solid at a room temperature and prevents free-CaO from being generated in steel slag. This rapidly-cooled steel slag has a spherical shape and is even heavier than natural aggregate, making it suitable for the aggregate of radiation shielding concrete. This study deals with the radiation shielding property of concrete that uses the rapidly-cooled steel slag from the oxidizing process in the converter furnace as fine aggregate. It was shown that the radiation shielding performance of concrete mixed with rapidly-cooled steel slag is even more superior than that of ordinary concrete.

• 한국산업보건학회지
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• 제6권2호
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• pp.222-248
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• 1996

This study was designed to survey misused expression in 37 KS (Korean Industrial standards) related to personal protective equipment. The results were as follows: 1. One hundred and twenty five misused expressions were found - 44 expressions were used illogically (35.2 %). 80 expressions were wrongly described (64.0 %) The types of illogically misused are: 10 illogical cases, 4 cases of a wrongly designated provision when cited, 12 cases of the lack of provisons for KS, 7 cases of a inappropriate uses of units, 8 cases of an overlapped sizes between standards. - The types of expressions wrongly described are: 30 cases of confusion in using an terms, 4 case of making an error when proofreading, and 29 cases of choosing words not appropriate to describe technical standard, 18 cases of unclear provisons due to missing phrases and terms, and 11 cases of provisons described differently from original intended purposes. 2. There is one case, where the same standard is categorized as two different names. There are three major causes of the misused expressions as seen from the following summary: - Imitated the developed countries' standards without filtering them by considering domestic law and ocher KS standards. - Tended to create each definition for each standard instead use of the basic standard. - Insufficiency of synthetic examination to the correlation between standards.