• The KSFM Journal of Fluid Machinery
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• v.11 no.1
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• pp.9-17
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• 2008

A numerical study for three-dimensional laminar flow in the entrance region of helical tubes connected with straight ones is carried out to investigate the effects of Reynolds number, pitch and curvature ratio on the oscillation periods of the flow. The fully elliptic governing equations were solved by means of a finite volume method. The fully developed laminar flow boundary condition was applied at the straight tube inlet. This results cover a curvature ratio range of 1/10${\sim}$1/320, a pitch range of 0.0${\sim}$3.2, and a Reynolds number range of 62.5${\sim}$2000. A comparison is made with previous experimental correlations and numerical data. The developments of velocity, local and average friction factors are discussed. The average friction factors are oscillatory in the entrance region of helical pipes. It has been found that the angle required for the flow to be similarly developed is most affected by the curvature ratio. The pitch and Reynolds number do not have any significant effect on the angle. The characteristic angle ${\phi}_c(={\phi}/sqrt{\delta})$, or the characteristic length to diameter ratio $s_c(=l\sqrt{\delta} cos(atan{\lambda})/d)$, can be useful to represent the development of flow in helical tubes. As the pitch increases and as the curvature ratio and Reynolds number decrease, the amplitude and the number of flow oscillations along the main streamwise direction decrease.

• Archives of design research
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• v.12 no.4
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• pp.109-118
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• 1999

In the respect of automobile history, the tendency to the development of automobiles for the latest 100 years has been leaded by technical performances. Especially, with the rapid growth of the newest electronic industry, the technical know-hows of automobiles improved in short terms have brought about outstanding results. The differences of the technical know-hows are little between some of the famous automobile manufacturing industries and the rising. So, now, the automobile design became a basis in selecting a car. The latest tendency to automobile style in accordance with the improvement of a universal life quality has been changed to a characteristic design meeting various needs of customers. RV, UV, MPV(and so forth ) meeting their needs made an appearance, or a characteristic model derived from them respectively appeared. We tried to study a new mini SUV-typed-concepcar design with a touch of the next concept. The whole design process from our researches to the end hard model was performed at the Design Center, Daewoo Automobile, based on the automobile design processes. Especially, We styled an automobile concept as inexpensive, characteristic, new one to have a car easily at the young and made an analysis of customers' responses for referring to this study in generating the next SUV-typed-automobile.

• Analytical Science and Technology
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• v.35 no.2
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• pp.69-81
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• 2022

The method of measuring and classifying the energy category of neutrons directly using raw data acquired through a CZT detector is not satisfactory, in terms of accuracy and efficiency, because of its poor energy resolution and low measurement efficiency. Moreover, this method of measuring and analyzing the characteristics of low-energy or low-activity gamma-ray sources might be not accurate and efficient in the case of neutrons because of various factors, such as the noise of the CZT detector itself and the influence of environmental radiation. We have therefore developed an efficient method of analyzing radiation characteristics using a neutron and gamma-ray analysis algorithm for the rapid and clear identification of the type, energy, and radioactivity of gamma-ray sources as well as the detection and classification of the energy category (fast or thermal neutrons) of neutron sources, employing raw data acquired through a CZT detector. The neutron analysis algorithm is based on the fact that in the energy-spectrum channel of 558.6 keV emitted in the nuclear reaction ¹¹³Cd + ¹n → ¹¹⁴Cd + in the CZT detector, there is a notable difference in detection information between a CZT detector without a PE modulator and a CZT detector with a PE modulator, but there is no significant difference between the two detectors in other energy-spectrum channels. In addition, the gamma-ray analysis algorithm uses the difference in the detection information of the CZT detector between the unique characteristic energy-spectrum channel of a gamma-ray source and other channels. This efficient method of analyzing radiation characteristics is expected to be useful for the rapid radiation detection and accurate information collection on radiation sources, which are required to minimize radiation damage and manage accidents in national disaster situations, such as large-scale radioactivity leak accidents at nuclear power plants or nuclear material handling facilities.

• Korean Journal of Social Welfare Studies
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• v.40 no.1
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• pp.63-86
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• 2009

This research aims to focus on how the perception of discrimination changes through the mediation effect of various leisure activities between the characteristic of disability and perception of discrimination. This research is based on the 2005 survey of the disabled conducted by the Korea Institute for Health and Social Affairs, which studied 1,241 seniors over 65 with physical disabilities. The results of the study are as follows. First, the type of disability, duration of disability, and IADL are the influencing factors to the relation between the characteristic of disability and individual perception of discrimination. Second, the type of leisure activities was influenced by the characteristics of their disability. Especially, the degree of IADL was statistically significant in choosing the type of leisure. Third, leisure activities with specific purposes, such as amusement and self-development, have only partial mediation effect on the relation between the characteristic of disability and individual perception of discrimination.

• Journal of Agricultural Extension & Community Development
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• v.13 no.1
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• pp.173-184
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• 2006

This study was diagnosed the managing of educational progress of homehelper training center proceeded with a goal to improve the proper direction to grasp of the contentment of education programs. In order to attain a research objective, I surveyed 18 charge of education person in homehelper training center. Through the problem of the mananging of homehelper education, I try to show the point for growth of homehelper training. First, the course of the education and training for home helper should be classified in the field of the service activity for home helper. Second, the education centers need to establish the weekend lecture or the night lecture for volunteer with an occupation. Third, the education centers need to division the educational course according a characteristic of student. Fourth, when the course is opened, the number of persons is suitable thirty. Fifth, it needs to add the education contents to establish an attitude with volunteer for elderly people.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.2
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• pp.120-126
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• 2005

We have proposed a characteristic method to estimate real composition when multi component oxide films are deposited by ALD. Final atomic concentration ratio was theoretically calculated from the film densities and growth rates for $HfO_2$ and $Al_2O_3$ using ALD processed HfxAhOz mms.W e have transformed initial source feeding ratio during deposition to fins] atomic ratio in $Hf_xAl_yO_z$ films through thickness factors ($R_{HFO_2}$ ami $R_{Al_2O_3}$) ami concentration factor(C) defined in our experiments. Initial source feeding ratio could be transformed into the thickness ratio by each thickness factor. Final atomic ratio was calculated from thickness ratio by concentration factor. It has been successfully confirmed that the predicted atomic ratio was in good agreement with the actual measured value by ICP-MS analysis.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.861-873
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• 2017

The present study was conducted to investigate the developmental characteristics of Propylea japonica Thunberg (Coleoptera : Coccinellidae), a predator of aphids under laboratory conditions. The development times of the egg and immature stages of Propylea japonica were investigated at ten constant temperatures(15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, 35 and $38{\pm}1^{\circ}C$; 14L:10D; $60{\pm}5%$ RH). Development time was longest at $17.5^{\circ}C$. The developmental periods of P. japonica from the time of egg oviposited to adult emergence was 36.9 days at $17.5^{\circ}C$, and it decreased ash temperature increasing. Threshold temperature of development and degree days of the P. japonica from egg to adult were $11.9^{\circ}C$ and 196.0 respectively. The Briere 2 and Lactin 2 modes were best fitted for all development stages. The distribution of completion of each development stage was explain relatively well that 2-parameter, 3-parameter and Logistic model except egg and pupal stage.

• Journal of the Korean Society of Food Culture
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• v.22 no.6
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• pp.653-664
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• 2007

This study intends to consider about the food culture during the latterly Chosun Dynasty through the genre paintings which are depicted realistically about the total food life figures for example not only the foods, but also that people who eat and drink the food and eating implements, eating methods. There are 9 pieces of works Kim hong-do's which are the best appraisal on the incorporated Korean emotion and on the real life of general public. Those are selected for this study's characteristics through the literature consideration. The characteristics of the tableware pottery and food culture are following things. The first is a white porcelain's development and popularization. In the latterly Chosun Dynasty period, the development of the agriculture and commerce made been connected to the affluent food cultures, these made increase the porcelain's use of upper classes and these made been connected to the development of the porcelain's cultures. The second is the development of various pottery with a dark brown glaze manufactures. The development of agriculture and economy power made bring the development of the kinds of sauces and Kimchi culture with an inflow of foreign crops and these made making the large an earthenware pot or jar which could store something during the long time. The third is the development of the small dining table on the eating the bread of idleness. In the Chosun dynasty period, the food style was been unified to he eating the bread of idleness and been lowered. These made developed of various small dining table through the underfloor heating system's generalization. The fourth is the development of the spoon with the soup culture. It is the East Asia called that the spoon culture boundary, this show the characteristic that we use the spoon mainly compare with another countries. Finally, it is universal use of the fixed quantitative implements. They could live quantitative life with the scales which are jar of soy sauce, liquor jug, jar, scoop leading a set of tableware.

• Korean Institute of Interior Design Journal
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• v.19 no.2
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• pp.90-98
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• 2010

The concepts of laws like regularity or persistence or recurrence those are discovered in nature, became the essential elements in speculative philosophy, study and scientific technology. Western civilization was spread out by these natural laws. As this background, this study is aimed to research the theories of natural laws and the development of geometry as the descriptive tools and the development aspects of the concepts of space. According to Whitehead's four theories on the natural laws, the result of this study that aimed like that as follows. First, the theories on the immanence and imposition of the natural laws were the predominant ideas from ancient Greek to before the scientific revolution, the theory on the simple description like the positivism made the Newton-Cartesian mechanism and an absolutist world view. The theory on the conventional interpretation made the organicism and relativism world view according to non-Euclidean geometry. Second, the geometrical composition of ancient Greek architecture was an aesthetics that represented the immanence of natural laws. Third, in the basic symbol of medieval times, the numeral symbol was the frame of thought and was an important principal of architecture. Fourth, during the Renaissance, architecture was regarded as mathematics that made the order of universe to visible things and the geometry was regarded as an important architectural principal. Fifth, according to the non-Euclidean geometry, it was possible to present the natural phenomena and the universe. Sixth, topology made to lapse the division of traditional floor, wall and ceiling in contemporary architecture and made to build the continuous space. Seventy, the new nature was explained by fractal concepts not by Euclidean shapes, fractal presented that the essence of nature had not mechanical and linear characteristic but organic and non-linear characteristic.

• Journal of The Korean Association of Information Education
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• v.9 no.3
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• pp.377-386
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• 2005

The technology development is the one of the motive leading power to change the world. At this point of time, the most countries in the world take notice of the gifted science education because they believe that the development of a high-grade manpower resources is the only way of the development of their own country. Before the gifted education, however, the study of the gifted characteristics should be achieved first. Analysis of the intellectual characteristic in the research of the gifted characteristic has been accomplished with many of standardized test tool, however, analysis of the non-intellectual characteristics has not been researched with real sources because of the measuring method and the vogue range. Accordingly, this research will analyzed characteristics of the gifted in computers to focus on the non-intellectual through the difference of normal child. The field of the gifted in computers, in particular, hardly has been researched because the beginning of this study has a short period of time. Therefore, this research focus on analysis of the non-intellectual characteristics of the gifted in computer so that we understand well gifted child in computers in education of that.