• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.81.2-81.2
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• 2012

To fabricate a metal mold for injection molding, hot-embossing and imprinting process, mechanical machining, electro discharge machining (EDM), electrochemical machining (ECM), laser process and wet etching ($FeCl_3$ process) have been widely used. However it is hard to get precise structure with these processes. Electrochemical etching has been also employed to fabricate a micro structure in metal mold. A through mask electrochemical micro machining (TMEMM) is one of the electrochemical etching processes which can obtain finely precise structure. In this process, many parameters such as current density, process time, temperature of electrolyte and distance between electrodes should be controlled. Therefore, it is difficult to predict the result because it has low reliability and reproducibility. To improve it, we investigated this process numerically and experimentally. To search the relation between processing parameters and the results, we used finite element simulation and the commercial finite element method (FEM) software ANSYS was used to analyze the electric field. In this study, it was supposed that the anodic dissolution process is predicted depending on the current density which is one of major parameters with finite element method. In experiment, we used stainless steel (SS304) substrate with various sized square and circular array patterns as an anode and copper (Cu) plate as a cathode. A mixture of $H_2SO_4$, $H_3PO_4$ and DIW was used as an electrolyte. After electrochemical etching process, we compared the results of experiment and simulation. As a result, we got the current distribution in the electrolyte and line profile of current density of the patterns from simulation. And etching profile and surface morphologies were characterized by 3D-profiler(${\mu}$-surf, Nanofocus, Germany) and FE-SEM(S-4800, Hitachi, Japan) measurement. From comparison of these data, it was confirmed that current distribution and line profile of the patterns from simulation are similar to surface morphology and etching profile of the sample from the process, respectively. Then we concluded that current density is more concentrated at the edge of pattern and the depth of etched area is proportional to current density.

• Journal of Engineering Education Research
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• v.20 no.6
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• pp.68-75
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• 2017

This study has a purpose to analyse changes in perception and image about engineering and technology of students who participated in the engineering camp. To achieve this objective, the questions were as follows. 1) What about participants' image difference for engineering before and after participating the engineering camp 2) What about participants' image difference for technology before and after participating the engineering camp. For this study, the program was progressed from Aug in 2017 and the data was collected from 88 students, middle school seniors and high school freshmen. The results of this study were as follows: First, secondary students perceived 'valuable(6.74)', 'meaningful(6.73)', 'rich(6.40)', 'collaborative(6.42)', 'nice(6.22)' as high image rank of the positive response for engineering. On the other hand, 'complex(3.59)', 'labored(3.80)', 'hard(4.66)', 'dangerous(4.48)', 'cold(4.86)' were perceived as low image rank of the negative response for engineering. We can realize that they generally has the image that engineering is valuable, meaningful and nice but also labored, complex and hard. The students who participated in the engineering camp showed the greatest difference in 'complex - simple' and 'dangerous - safe' engineering categories before and after the camp, followed by 'cold - hot', 'labored - easy', and 'hard - soft', respectively. Second, secondary students perceived 'meaningful(6.58)', 'valuable(6.55)', 'wide(6.38)', 'nice(6.37)', 'strong(6.25)' as high image rank of the positive response for technology. On the other hand, 'complex(3.85)', 'labored(3.93)', 'hard(4.62)', 'dangerous(4.72)', 'cold(5.05)' were perceived as low image rank of the negative response for technology. The students who participated in the engineering camp had the big change in 'hard - soft' technology category before and after the camp, followed by 'complex - simple', 'labored - easy', 'theoretical - practical' and 'dangerous - safe', respectively. We can see that the negative images for technology which were complex, labored, dangerous, theoretical was improved with positive image such as simple, easy, safe and practical, after conducting the engineering camp. In conclusion, both image recognitions for engineering and technology have improved after the camp. It means that interesting and entertaining engineering-technology program can boost interests in engineering and technology which felt difficult, so that images about them can be turned out positive. Also, it is possible to reduce avoidance of natural science and engineering subjects, as part of the purpose of training creative talents in science and engineering, so it can be said that the engineering camp is highly meaningful because it can lead students into the field of science and engineering.

• Korean Journal of Construction Engineering and Management
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• v.8 no.2
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• pp.146-154
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• 2007

The u-City construction project has become a hot topic In the construction market because it seems economic value-added field for construction firms. However, construction firms don't willingly participate in the u-City construction market because the future business environments for the u-City are very uncertain. Scenario planning is a very powerful method in managing this complex planning situation and is based on scenarios that help each enterprise appropriately adapt itself to its own business environments. Therefore it Is based on the main principles of systems thinking and multiple futures. For the purpose of dealing with such uncertainties, this paper attempts to develop the possible market scenarios of the u-City construction market through a scenario planning approach. From this perspective, we considered various aspects of the u-City construction such as market demands, technology development, policy level and management environment. After considering the relevant issues, we identified the main trends and key uncertainties. Then, we developed three coherent u-City construction market scenarios. On the basis of the proposed scenarios, the business strategies of potential construction firms in the u-City construction market has been formulated. Therefore, construction firms can use these scenarios as a basic data for market analysis and business strategy. Therefore, this paper is able to enhance the participation of construction firms in the u-City construction market.

• Journal of the Korean Home Economics Association
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• v.19 no.2
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• pp.11-24
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• 1981

The objectives of the study were to determine 1) if energy consumption and conservation vary in clothing, food, and housing with independent variables-size of household, homemaker's age, employment, and level of education, level of living, type of house, electricity use, and all energy use, and 2) if there is a correlation among energy conservation practices in clothing, food, and housing. Questionnaires wee given to the randomly selected homemakers in Seoul in July, 1980. Data from 620 responses were analyzed by F-test (Analysis of Variance) and Correlation. The results are as follows: 1. Clothing (1) the scores of the conservation practices I clothing were generally high. /However, it was found that a) they did not practice in wearing heavy under clothes and behavior outer clothing to cope with cool room temperature in the winter, b) they did not use bleach for laundry, but they used boiling method, and c) they did not have enough knowledge on Permanent Press finish. (2) energy conservation practices in clothing were significantly related to level of living and homemakrer's level of education. a) The higher the level of living, the higher scores in the knowledge were found. b) the higher the homeakcer's level of education, the higher scores in the knowledge and ironing were obtained. 2. Food (1) The scores of the conservation practices in food were generally high. However, it was found that scientific cooking methods were not performed such as a) to use measuring spoons, cups, and timers, b) to practice a simple method in using solor energy for warming water, c) to use thermos for the hot water tea or coffee, but they boiled water whenever necessary, and b) to use the pressure cooker whenever possible. (2) Energy conservation practices in food were significantly related to homemaker's employment and type of dwellings. a) The scores of full-time homemakers (not gainfully employed) were higher than gainfully employed homemakers. b) Families in traditional Korean dwellings revealed higher scores than those in apartment or western style dwellings. 3. Housing (1) The scores of the conservation practices in housing were generally high. However, it was found that a) they did not install fans in the kitchen, bathroom, and attic in the summer, b) they did not install a humidifier for tolerating a lower room temperature in the winer, c) they did not practice to make plans for the door of the refrigerator remained open for the shortest time, d) they did not install or use a local lighting with a general lighting for reading and cooking, and e) they usedaluminum foil without the knowledge of the heat reaction of its shiny and dull sides. (2) energy conservation practices in housing were significantly related to homemaker's employment and level of education, economic status, types of dwelling, and all energy use, a) Full-time homeakers had higher scores than gainfully employed homeakers. b) the higher the homemaker's level of education and economics status, the higher scores were obtained. c) Homeakers with their own house scored higher points than those with rented houses. And families in apartment or row houses scored higher points than those in traditional korean or western style dwellings. d) The higher the consumption rate of electricity and all energy, the higher scores were revealed. 4. correlation there was a significant correlation among energy conservation practices I clothing, food, and housing.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.5
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• pp.516-523
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• 2005

This study was performed to investigate dietary behaviors and consumption of health food in cancer patients. The subjects were 163 cancer patients recruited from the general hospital in Seoul, Korea. The data were obtained by the structured self administered questionnaire. The mean age of subjects was 51 years. Most of subjects didn't eat the visual fat of meat and chicken skin. The mealtime of the subjects was generally regular and most of subjects had breakfast. The subjects of this survey liked to eat foods with sweet taste but disliked to eat hot, salty and sour taste ones. The preference for fish, marine products and vegetables was high but that for instant foods and frying foods was very low. Most of subjects consumed the foods that is generally known as anticancer foods such as vegetables and fruits. On the other hand, most of subjects didn't intake butter, margarine, and frying foods that is known as risk factors of cancer. The majority of subjects$(84.7\%)$ consumed the health food The main reasons for taking health foods by subjects were to cure disease$(58.0\%)$, to prevent disease$(45.3\%)$, to supply nutrients$(39.3\%)$, to maintain the mental state$(12.7\%)$ and to recover fatigue$(10.7\%)$. Majority of subjects$(66.0\%)$ spent money more than 200,000 won/month to buy health foods. The purchasing channels of health foods by subjects were recommendation by family or friend$(64.0\%)$, by physician/pharmacist$(18.0\%)$ and by nutritionist or dietician(6.0), and advertisement through TV or radio$(12.0\%)$. The types of taking health foods of the subjects were vegetable extracted food$(60.0\%)$, mushrooms$(51.3\%)$, Lactobacillus food$(25.3\%)$, enzyme food$(22.6\%)$ calcium containing food$(20.0\%)$ and so on. The results of the current study show that although many cancer patients already practice healthy dietary behaviors, there is a substantial proportion who do not and most of cancer patients consume health foods.' Further intervention is needed to explore the effect of health foods in cancer patients

• Management & Information Systems Review
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• v.33 no.1
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• pp.119-138
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• 2014

Since the mid-1980s, the role of Corporate Social Responsibility(CSR) has become a hot issue in business world due to increasing comparative importance of firms in current society. The purposes of this research are to analyze empirically the relationship between workplace spirituality and organizational citizenship behavior, also to analyze the moderating effects of Leader-Member Exchange(LMX) on the relationship between workplace spirituality and organizational citizenship behavior in the social enterprises. For these purposes, literature review and survey research were conducted. The suggested hypothetical relationships were tested with primary data from a sample 552 employees of social enterprises. The main findings of this study are as follow ; First, inner life and sense of community which are composed workplace spirituality have positive influence sportsmanship and courtesy. second, sense of community have differential influence on organizational citizenship behavior by LMX. In conclusion, inner life and sense of community are expected to improve sportsmanship and courtesy, important of LMX in the social enterprises.

• Nuclear Engineering and Technology
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• v.27 no.3
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• pp.393-402
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• 1995

The structural analysis of the reactor coolant system mainly consist of too fields. The one is the static analysis considering the impact of pressure and temperature built up during normal operation. The other is the dynamic analysis to estimate the impact of postulated events such as the seismic loads or postulated branch line pipe breaks event. Since the most important goal of the RCS structural analysis is to prove the safety of the RCS during normal operation or postulated events, a widely proven theory having enough conservatism is adopted. The load occurring on the RCS during normal operation is considered as the basic design loading condition throughout whole plant life time. The most typical characteristic of the RCS during normal operation is the thermal expansion of the RCS caused by reactor coolant with high temperature and pressure. Therefore, the exact estimation on the thermal movement of the RCS is needed to get more clear understanding on the thermal movement behavior of the RCS. In this study, the general structural analysis concept and modeling method to evaluate the thermal movement of the RCS under the normal plant operation condition are presented. To discuss the validation of the suggested analysis, analysis results are compared with the measured data which ore referred from the standardized 1000 MWe PWR plant under construction.

• Solar Energy
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• v.15 no.3
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• pp.3-14
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• 1995

The Direct Contact heat Exchanger(DCHX) has been widely studied in the chemical industry for many years due to its inherent simplicity as a counter-current divice for heat and mass transfer. In many solar systems, the DCHX unit can be combined with the thermal storage unit, or alternatively, it can be used separately from the storage unit, much like an external(to storage) closed heat exchanger system. In the present work, the spray column type of direct contact heat exchangers are studied extensively to harness the solar energy for hot water and spaced heating. Some of the major considerations that are involved in the design of heat exchangers in this study are that : working fluid is a hydrocaabon(such as Texaterm) or water which is either lighter or heavier than storage medium. The experimental data have revealed some interesting characteristics concerning the application of DCHXs for solar energy utilization. These experiments are carried out in the line of solar heating system, major results are as follows : 1) the flow and aspect of working fluid drop for maxium heat transfer 2) efficiency and volumetric heat transfer coefficient of D.C.H.X with a heavier working fluid are higher than those of D.C.H.X with a lighter working fluid.

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.1126-1134
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• 1996

The physical characteristics changes of carrots during drying were studied to minimize the quality degradation by applying improved drying process and pretreatment method. Physico-chemical properties of the product were analyzed, and then, drying mechanisms were explained by diffusion coefficients and drying models. In hot air drying process, the drying and rehydration efficiencies were high at low relative humidity and high temperature. Browning degree and specific volume also showed similar trend to drying efficiency. Diffusion coefficient, which describes moisture transfer, was also high at low relative humidity and at high temperature. It was verified using. Arrhenius equation that drying process was influenced by temperature. It was also observed during experiment that temperature changes were more effective in drying than relative humidity changes. Quadratic model was the most fittable in explaining the process. As a result of analyzing the experimental data with respect to the drying time, the contents of carotene and moisture could be modeled as a polynomial. As the air velocity increased, drying performance and rehydration efficiency increased.

• Journal of the Korean association of regional geographers
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• v.21 no.2
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• pp.364-378
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• 2015

As safety Issue becomes one of the hot topics, practical researches and feasible policies are in needs not only for central government but also local officers. The previous studies focused on organizational or institutional approaches and on functional efficiencies, especially how to integrate disaster data at every stage of disaster from preparedness to recovery. Physical and social environments differ from among others, top-down disaster management plan cannot work, and therefore more practical statistics and survey is required to prepare the safety management plan for local government. We aim to suggest a safety environment survey framework and to apply it to two guns (Muan and Goheung). We considered main factors of the framework based on legal requirement for safety index and four stages of disaster progress. Two guns are located in remote area and have a population who are weak to disaster. Action items were drawn from the survey and analysis from the framework respectively. We expect this framework to be expanded to include more urbanized and complex areas.