• Korean journal of food and cookery science
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• v.12 no.2
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• pp.129-137
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• 1996

The purpose of this study was that to estimate the microbial and sensory quality by the method and time of holding in the step of holding of Cow's Knee Broth, Stir-Fry Pork and Cooked Cuttlefish that were provide at the industry foodservice establishment, then to suggest safer feeding by the reasonable holding method. The results are as follows: Cow's Knee Broth: holding at room temperature was shown that the number of mi- crobiology by passage of the holding time was higer than the case of holding at steam table, but it was lower after reheating it. As a result of sensory test, it was exellent to holding at steam table and to reheat after holding room temperature within four hours and six hours each. Stir-Fry Pork: as a result of microbial analysis, in the case of holding at the steam table microbes increased safer two hours, but after four and six hours they little reduced. In the case of holding at room temperature the number of microbes increased according to the passage of time. As a result of sensory analysis, its taste of room temperature holding was fine until four and six hours each. Cooked Cuttlefish: as a microbial analysis, it was shown that the amount of total plate counts of room temperature holding ten times as high as the latter after six hours. As the result of sensory analysis, the cold holding was better until six hours and the room temperature holding was fine just until two hours. As a result of food poisoning bacteria, it was negative in every test in sample against Salmonella, Staphylococcus aureus, Vibrio parahaemolyticus.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.413-418
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• 2011

The thermodynamic properties of steam table are obtained by measurement or approximate calculation under appropriate assumptions. Therefore they are supposed to have basic measurement errors. And thermodynamic properties should be modeled through function approximation for using in numerical analysis. In order to make noised thermodynamic properties corresponding to measurement errors, random numbers are generated, adjusted to appropriate magnitudes and added to original thermodynamic properties. Both neural networks and quadratic spline interpolation method are introduced for function approximation of these modified thermodynamic properties in the saturated water based on pressure and temperature. In analysis spline interpolation method gives much less relative errors than neural networks at both ends of data. Excluding the both ends of data, the relative errors of neural networks is generally within ${\pm}0.2%$ and those of spline interpolation method within ${\pm}0.5$~1.5%. This means that the neural networks give smaller relative errors compared with quadratic spline interpolation method within range of use. From this fact it was confirmed that the neural networks trace the original values better than the quadratic interpolation method and neural networks are more appropriate method in modelling the saturated steam table.

• Journal of KSNVE
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• v.5 no.4
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• pp.543-553
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• 1995

Modern steam turbine generators are being built as a higher power and larger system, experiencing more frequent starts and stops of operation due to a constant change of power demands. Hence, they are inevitably more vulnerable to various vibrations, and more often exposed to the danger of sudden vibration accidents than ever before. Even under the circumstances, in order to secure the system reliability of steampower plants and there by to supply safely the public electricity, it is important to prevent a sudden vibration accident in one hand and even when it happens, to raise an operating efficiency of the plants throught swift and precise treatments in the other. In this study, an interactive vibration diagnostic system has been developed to make the on-site vibration diagnosis of steam turbine generators possible and convenient, utilizing a note-book PC. For this purpose, at first the principal vibration phenomena, such as various unbalance and unstable vibrations as well as rubbing, misalignment, and shaft crack vibrations, have been systematically classified as grouped parameters of vibration frequencies, amplitudes, phases, rotating speeds at the time of accident, and operating conditions or condition changes. A new complex vibration diagnostic table has been constructed from the causal relations between the characteristic parameters and the principal vibration phenomena. Then, the diagnostic system has been developed to screen and issue the corresponding vibration phenomena by assigning to each user-selected combination of characteristic parameters a unique characteristic vector and comparing this vector with a diagnostic vector of each vibration phenomenon based on the constructed diagnostic table. Moreover, the diagnostic system has a logic whose diagnosis may be performed successfully by inputing only some of the corresponding characteristic parameters without having to input all the parameters. The developed diagnostic system has been applied to perform the diagnosis of several real cases of steam turbine vibration accidents. And the results have been quite satisfactory.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.12
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• pp.809-814
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• 2016

A standard procedure for determining water-steam properties has been established through an international collaboration in addition to a domestic effort. The current accepted international standard for industrial application is based on the IAPWS-IF97 (International Association for the Properties of Water and Steam-Industrial Formation 97). Based on this standard, the ASME (American Society of Mechanical Engineers)/NIST (National Institute of Standard and Technology) developed the REPROP program in the USA, and the JSME (Japan Society of Mechanical Engineers) developed the steam table and calculation code. Upon applying this standard procedure, modified procedures were proposed for computational convenience, particularly in the supercritical pressure region where non-smooth variations of water-steam properties were distinctively observed. In this paper, the internationally adopted procedures and the progress of related activities are briefly summarized. Some practical considerations are presented for the efficient execution of computational code.

• Journal of Korea Technology Innovation Society
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• v.8 no.spc1
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• pp.499-524
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• 2005

The economic spillover effect from technology self-reliance of NSSS(nuclear steam supply system) by Korea Atomic Energy Research Institute was evaluated. Both production spillover effect and value added spillover effect were estimated by using Input-Output table. The production spillover effect from technology self-reliance of NSSS was estimated as 135 trillion Won during 1986-2015, while the value added spillover effect was 69 trillion Won during the same period. Besides, it was found that the technology self-reliance made great contribution to unquantifiable economic benefits such as enhancement of overall nuclear technology level, improvement of the role in international nuclear society, and improved potential to nuclear technology export.

• Korean journal of food and cookery science
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• v.19 no.5
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• pp.631-639
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• 2003

In order to control the quality and safety of cooked foods, production and holding methods of foods should be carefully studied and applied to the foodservice industry. Therefore studies on microbiological, nutritional, physicochemical and sensory quality are essential in this area. The purpose of this study was to evaluate the chemical and microbial qualities of cooked foods during preparation and holding From the results, the following guidelines should be adhered to give effective quality control when holding foods after cooking in foodservice institutions, as well as to provide quality foods when selling cooked foods at commercial establishments. Sauteed and simmered foods such as sauteed chicken meat & vegetables and simmered pork in soy sauce satisfy the standard for microorganisms till 1-3 hours of room temp. holding, 6-18 hours at 60$^{\circ}C$ steam table, and 12-18 hours at 80$^{\circ}C$ heating table.

• Journal of computational fluids engineering
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• v.20 no.4
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• pp.14-20
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• 2015

Without electirc power to cool down the hot reactor core, passive systems utilizing natural circulation are becoming a big specialty of recent neculear systems after the severe accident in Fukusima. When we consider the natural circulation in a pool, thermal mixing phenomena may start from single phase circulation and can continue to two phase condition. Since the CUPID code, which has been developed for two-phase flow analysis, can deal with the phase transition phenomena, the CUPID would be pertinent to natural convection problems in single- and two-phase conditions. Thus, the CUPID should be validated against single- and two-phase natural circulation phenomena. For the first step of the validation process, this study is focused on the validation of single-phase natural circulation. Moreover, the CUPID code solves the fluid properties by the relationship to pressure and temperature from the steam table considering non-condensable gas effects, so that the effects from variable properties are included. Simple square thermal cavity problems are tested for laminar and turbulent conditions against numerical and experimental data. Throughout the investigation, it is found that the variable properties can affect the flow field in laminar condition, but the effect becomes weak in turbulence condition, and the CUPID code implementing steam table is capable of analyzing single phase natural circualtion phenomena.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.685-690
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• 2008

In numerically evaluating the thermal performance of the heat exchanger, numerical values of thermodynamic properties such as temperature, pressure, specific volume, enthalpy and entropy are required. But the steam table or diagram itself cannot be directly used without modelling. In this study the applicability of neural networks in modelling superheated water vapor was examined. The multi-layer neural networks consist of an input layer with 2 nodes, two hidden layers with 15 and 25 nodes respectively and an output layer with 3 nodes. Quadratic spline interpolation was also applied for comparison. Neural networks model revealed smaller percentage error compared with spline interpolation. From this result, it is confirmed that the neural networks could be a powerful method in modelling the superheated water vapor.

• Journal of Korea Water Resources Association
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• v.31 no.6
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• pp.667-674
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• 1998

Numerical models simulating the process of NAPL from contaminated soil or groundwater through steam injection can be a useful tool for designing and evaluating the cleanup strategy under various field conditions. One and two dimensional numerical analyses were conducted based on the governing equations describing the NAPL removal as a non-isothermal, multi-phase and multi component process. Relatively good agreements were obtained between the numerical results and the observations from one-dimensional laboratory experiment, except some discrepancy due to experimental difficulties. Simulation effectively identified the steam displacement process of xylene floating on the water table and TCE sinking on the aquifer bottom in a two-dimensional analysis. Overall, simulation models have a high potential in the design/appraisal of a system for field application of the technique as well as in the examination of complex processes such as vaporization which is hard to identify experimentally.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.401-407
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• 2011

The purpose of this study is to know the differences of MR spectra, obtained from normal volunteers by variable TE value, through the quantitative analysis of brain metabolites by peak integral and SNR between 1.5T and 3.0T, together with PRESS and STEAM pulse sequence. Single-voxel MR proton spectra of the human brain obtained from normal volunteers at both 3.0T MR system (Magnetom Trio, SIEMENS, Germany) and 1.5T MR system (Signa Twinspeed, GE, USA) using the STEAM and PRESS pulse sequence. 10 healthy volunteers (3.0T:3 males, 2 females; 1.5T : 3 males, 2 females) with the range from 22 to 30 years old (mean 26 years) participated in our study. They had no personal or familial history of neurological diseases and had a normal neurological examination. Data acquisition parameters were closely matched between the two field strengths. Spectra were recorded in the white matter of the occipital lobe. Spectra were compared in terms of resolution and signal-to-noise ratio(SNR), and echo time(TE) were estimated at both field strengths. Imaging parameters was used for acquisition of the proton spectrum were as follow : TR 2000msec, TE 30ms, 40ms, 50ms, 60ms, 90ms, 144ms, 288ms, NA=96, VOI=$20{\times}20{\times}20mm3$. As the echo times were increased, the spectra obtained from 3.0T and 1.5T show decreased peak integral and SNR at both pulse sequence. PRESS pulse sequence shows higher SNR and signal intensity than those of STEAM. Especially, Spectra in normal volunteers at 3.0T demonstrated significantly improved overall SNR and spectral resolution compared to 1.5T(Fig1). The spectra acquired at short echo time, 3T MR system shows a twice improvement in SNR compared to 1.5T MR system(Table. 1). But, there was no significant difference between 3.0Tand 1.5T at long TE It is concluded that PRESS and short TE is useful for quantification of the brain metabolites at 3.0T MRS, our standardized protocol for quantification of the brain metabolites at 3.0T MRS is useful to evaluate the brain diseases by monitoring the systematic changes of biochemical metabolites concentration in vivo.