• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.2
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• pp.127-134
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• 2020

High supersonic aircraft are exposed to high temperature environments by aerodynamic heating during supersonic flight. Thermal protection system structures such as double-panel structures are used on the skin of the fuselage and wings to prevent the transfer of high heat into the interior of an aircraft. The thin-walled double-panel skin can be exposed to acoustic loads by supersonic aircraft's high power engine noise and jet flow noise, which can cause sonic fatigue damage. Therefore, it is necessary to examine the behavior of supersonic aircraft skin structure under thermal-acoustic load and to predict fatigue life. In this paper, we designed and fabricated thermal-acoustic test equipment to simulate thermal-acoustic load. Thermal-acoustic testing of the titanium specimen under thermal-acoustic load was performed. The analytical model was verified by comparing the thermal-acoustic test results with the finite element analysis results.

• Journal of Society of Preventive Korean Medicine
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• v.4 no.1
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• pp.32-50
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• 2000

On the process of research in the plan on oriental medical participation in the industrial health sponsored by BK21 project, we carried out the oriental medical health examination program for workers during former half-year We reached the conclusion as follows, 1. The oriental medical health examination program is contents and formalities that should be determined by present industrial health system, based on the oriental medical system and scholastic character, and included probability of the western and oriental medical cooperation. 2. The oriental medical health examination program can promote capability of individual health management and productive power of workers, and it is capable to manage on the self-conscious symptoms and macroschophically approach to their environment 3. The oriental medical health examination program that we have developed, is flow as questionare, understanding of working environment, information of result and later management. It is composed of three fields as follow , first, use of pulse diagnostic apparatus, understanding of the health promotion life style, and diagnosis of the oriental medical doctor, second, analysis of constitution, third, photographing for understanding of the musculoskeletal disorders, questionare for musculoskeletal self-conscious symptoms, and diagnosis of oriental medical doctor. 4. The oriental medical health examination program that we have developed, progressive from the view point of health, makes the oriental medical doctor's roll more important. It is the first trial at the western and oriental medical cooperation and characterized by excellence about musouloskeletal disorders. But it need to be improved in aspects of time and specialist on the health examination, diagnostic apparatus, control of examinant and later management. So we think that it needs research on the employment of health examination specialist, establishment of later management system, development of significantly diagnosable standard and assessable form on the health examination, and contents of health examination on the western and oriental medical cooperation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.3
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• pp.115-121
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• 2012

Sapphire single crystals have been highlighted for epitaxial gallium nitride films in high-power laser and light emitting diode (LED) industries. Among the many crystal growth methods, the Kyropoulos process is an excellent commercial method for growing larger, high-optical-quality sapphire crystals with fewer defects. Because the properties and growth behavior of sapphire crystals are influenced largely by the temperature distribution and convection of molten sapphire during the manufacturing process, accurate predictions of the thermal fields and melt flow behavior are essential to design and optimize the Kyropoulos crystal growth process. In this study, computational fluid dynamic simulations were performed to examine the effects of the crucible geometry aspect ratio on melt convection during Kyropoulos sapphire crystal growth. The results through the evolution of various growth parameters on the temperature and velocity fields and convexity of the crystallization interface based on finite volume element simulations show that lower aspect ratio of the crucible geometry can be helpful for the quality of sapphire single crystal.

• Progress in Superconductivity and Cryogenics
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• v.15 no.2
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• pp.34-38
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• 2013

AC Losses for face to face stacks of four identical coated conductors (CCs) were numerically calculated using the H-formulation combined with the E-J power law and the Kim model. The motive sample was the face to face stack of four 2 mm-wide CC tapes with 2 ${\mu}m$ thick superconducting layer of which the critical current density, $J_c$, was $2.16{\times}10^6A/cm^2$ on IBAD-MgO template, which was suggested for the mitigation of ac loss as a round shaped wire by Korea Electrotechnology Research Institute. For the calculation the cross section of the stack was simply modeled as vertically aligned 4 rectangles of superconducting (SC) layers with $E=E_o(J(x,y,t)/J_c(B))^n$ in x-y plane where $E_o$ was $10^{-6}$ V/cm, $J_c$(B) was the field dependence of current density and n was 21. The field dependence of the critical current of the sample measured in four-probe method was employed for $J_c$(B) in the equation. The model was implemented in the finite element method program by commercial software. The ac loss properties for the stacks were compared with those of single 4 cm-wide SC layers with the same critical current density or the same critical current. The constraint for the simulation was imposed in two different ways that the total current of the stack obtained by integrating J(x,y,t) over the cross sections was the same as that of the applied transport current: one is that one fourth of the external current was enforced to flow through each SC. In this case, the ac loss values for the stacks were lower than those of single wide SC layer. This mitigation of the loss is attributed to the reduction of the normal component of the magnetic field near the SC layers due to the strong expulsion of the magnetic field by the enforced transport current. On the contrary, for the other case of no such enforcement, the ac loss values were greater than those of single 4cm-wide SC layer and. In this case, the phase difference of the current flowing through the inner and the outer SC layers of the stack was observed as the transport current was increased, which was a cause of the abrupt increase of ac loss for higher transport current.

• Journal of Korea Water Resources Association
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• v.30 no.1
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• pp.83-93
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• 1997

The purpose of the study is to analyze the sensitivity of the parameters that affect the runoff and water quality in the studied drainage basins. SWMM model is applied to the four drainage basins located at Namgazwa and Sanbon in Seoul and Gray Haven and Kings Creek in the USA. first of all, the optimum values of the parameters which have least simulation error to the observed data, are detected by iteration procedure. These are used as the standard values which are compared against the procedure. These are used as the standard values which are compared against the varied parameter values. In order to catch the effectiveness of the parameters to the computing result, the parameters are changed step by setp, and the results are compared to the standard results in flowerate and quality of the sewer. The study indicates that the discharge is greatly affected by the types of runoff surface, i.e., impervious area remarkably affects the peak flow and runoff volume while the surface storage affects the runoff volume at mild sloped basins. In addition, the major parameters affecting the pollution concentrations and loadings are the contaminant accumulation coefficient per unit area per time and the continuous dry weather days. Furthermore, the factors that affect the water quality during the initial rainfall period are the rainfall intensity, transport capacity coefficient and its power coefficient. Consequently, in order to simulate the runoff-water quality, it is needed to evaluate previous data in the research performed for the studied basins. To accurately estimated from the tributary areas and the rational computation methods of the pollutants calculation should be introduced.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.414-419
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• 2010

Hyphenated-HPLC techniques combine the separation power of HPLC with the structural and bioactivity information provided by NMR, ESI/MS, and an on-line antioxidant screening system. The major advantages over the traditional off-line techniques are rapidity and efficiency. In this study, we used hyphenated HPLC techniques including online HPLC-ABTS, LC-NMR, and LC-MS todirectly identify the major antioxidants of safflower (Carthamus tinctorius L.) seeds. The results demonstrated that the major antioxidant compounds from on-line HPLC-ABTS analysis were identified as 8'-hydroxyarcgenin-4'-O-$\beta$-D-glucoside, N-(p-coumaroyl) serotonin, and N-feruloylserotonin. Among them, N-feruloylserotonin accounted for almost 50% of the ABTS radical scavenging activity of the total extract. The results demonstrate that HPLC hyphenated techniques can be used to rapidly screen and structurally identify antioxidants from crude plant extracts.

• Journal of the Korean Vacuum Society
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• v.22 no.2
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• pp.66-78
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• 2013

In order to develop of 80 kW RF plasma torch system, we achieved three-dimensional simulations for the extraction of more information as temperature in torch and fluid behavior analysis, etc. The position of powder injection tube, the plasma discharge characteristics with various input current and various length of ceramic tube, and the plasma temperature characteristics with process gas flow rate such those was simulated. RF thermal plasma torch designed by simulation was manufactured that was measured to the maximum of 89.3 kW power. The mass production using developed 80 kW RF thermal plasma torch system were investigated by characteristics manufactured of Si nano powder. The mass-production level of Si nano-powder was average of 539 g/hr and high yield rate of 71.6%, respectively. The particle size distribution $D_{99}/D_{50}$ of manufacturing nano-powder was investigated to 1.98 as a good uniform.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.316-329
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• 2012

In this paper, optimum design process of ICP (Inductively Coupled Plasma) torch, which has been used widely in aerospace application, such as supersonic plasma wind tunnel, is presented. For this purpose, the behaviors of equivalent circuit parameters (equivalent resistance and inductance, coupling efficiency) were investigated according to the variations of torch design parameters (frequency, $f$, confinement tube radius, $R$ and coil turn numbers, $N$) in the basis of analytical and numerical MHD (Magneto Hydro-Dynamics) models combined with electrical circuit theory. From the results, it is found that equivalent resistance is increased with the increase of $f$ values but vice versa for equivalent inductance. For elevated values of $R$ and $N$, however, both parameters tend to increase. Based on these observations, ICP torch with a power level of 10 kW can be optimized at the design ranges of $f$=4~6 MHz, $R$=17~25 mm and $N$=3~4 to maximize the electrical coupling efficiency, which is the ratio of equivalent resistance to equivalent inductance.

• The Korean Journal of Food And Nutrition
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• v.24 no.2
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• pp.159-165
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• 2011

This study was carried out to investigate the quality characteristics of pear jam containing fresh ginger(G1) and ginger powders; dried ginger powder(G2), freeze-dried ginger powder(G3), and hot-air dried ginger powder(G4). The moisture, crude protein, and crude ash content of the control group were significantly higher than those of the experimental groups (p<0.001, p<0.05, p<0.01). The pH of the dried ginger powder added jam(G2) was the lowest(p<0.05). Texture profile analysis found that the dried ginger powder added jam(G2) had the highest firmness, consistency, cohesiveness, and resistance to flow/viscosity among all samples(p<0.001). Regarding the spread-meter value of the pear jam, the control group (G1) and hot air-dried ginger powder added jam(G4) had the highest values. The dried ginger power added jam(G2) had the lowest value among the samples(p<0.01). Regarding the color values of the pear jam, the control group(G1) had the highest L and b values. Hot-air dried ginger powder added jam(G4), on the other hand, had the lowest(p<0.001). The opposite was true for a value: hot-air dried ginger powder added jam(G4) had the highest. From the sensory evaluation, a positive trend was observed for the appearance of the dried ginger powder added jam(G2)(p<0.001). For sweetness, the dried ginger powder added jam(G2) had the highest value. A positive trend was observed for the overall acceptability of the dried ginger powder-added jam(G2)(p<0.001). Therefore, the dried ginger powder-added sample(G2) seemed to be the most appropriate to make pear jam with high acceptability.

• Korean Journal of Social Welfare
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• v.66 no.4
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• pp.53-75
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• 2014

The current status of Korean social work can be summarized as multiple complexities and ambiguities not only in ideological but in practical aspects. Although they have long been considered as an unique feature of social work as one of representative human service professions, the extent of such complexities are now reaching the culmination enough to raise the questions about the very nature of social work practice. This study aims to analyse such ambiguities and complexities around the field of social work in a systematic ways with the theory of liquid modernization, an creative framework for modern society, coined by Zygmunt Bauman who is now considered as one of the leading sociologist and thinker. The study shows clearly that social work in Korea is nowadays entering the phase of liquid modern society and specific features of liquidity of modern society such as consumerism, privatization, corruption of publicity etc are founded in the areas of social work. To make it worse, social work are thinking about the anachronical response to this flow of liquidity by selecting the strategies useful in solid modern era, not in the liquid one. In this context, the study suggests that social work practice have to prepare to adequate measures to secure its own autonomy and sustain genuine identification from the ruthless melting power of liquid modern society.