• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.223-229
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• 2011

When negative electron in x-ray tube is accelerated in to a high speed and then the currency of the electron is blocked by the target, x-ray happens by the conversion of the energy. The real area where the fast accelerated electron collides to a target area is called actual focal spot. When the string focused size is observed at the central ray side, where the direction x-ray comes out, the size seems to be reduced. This focus is called effective focal spot. According to radiation angle of x-rays tube, the degree of the negative pole side presents higher value than inclination, the amount of exposed radiation that patient receives differs by the angle of positive pole, which means effective focal spot is the variable. This paper presents the correlation between size of effective focal spot and amount of exposed radiation to the patient by it, and effective research for homogenized dose dispersion by the size of effective focal spot. In conclusion, following the focal size, effective range which was -8cm ~ 0 cm on average, was found and average dose rate was 0.019 R/min. Through this range, for patients with small radiation exposure, image with good density and resolution in aspect of diagnosing will be able to be obtained.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.443-445
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• 2001

As the new large buildings are continuously being built with the advanced technology and skills, an adequate size of electric room needs to be obtained so that engineers establish an efficient and reliable system in the electric room. Considering the current capacity, its expansion and its connecting system, the final size of it should be determined in order to bring an effective use of the building. Usually the extension of electricity capacity is on the increase after construction and it comes from the lack of scientific evaluation on the electric room. Later when the expansion of computer and important electric equipment that needs much capacity is impossible, it will cause a great deal of damage to the renting business of the building as well as becomes the unstable factors of the whole system. Therefore, it is important to have the exact method of calculating the effective size of electric room, the heart of the building, especially when the value of land price is very high. In addition, it should be calculated in an accurate way due to the diversification of the system and the compact size of the electricity equipment. However, the research on this area and the comparison and evaluation of the size after construction have not been made enough and the results of them have not been applied when calculating a new size of electric room. Accordingly, this study examines three methods prescribed in the standards of electricity installation technology through case analysis and suggests substantial data by system, capacity, and purpose.

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.643-655
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• 2005

The frontal crash optimization of S-shaped closed-hat section member using the homogenization method, design of experiment (DOE) and response surface method (RSM) was studied. The optimization to effectively absorb more crash energy was studied to introduce the reinforcement design. The main focus of design was to decide the optimum size and thickness of reinforcement. In this study, the location of reinforcement was decided by homogenization method. Also, the effective size and thickness of reinforcements was studied by design of experiments and response surface method. The effects of various impact velocity for reinforcement design were researched. The high impact velocity reinforcement design showed to absorb the more crash energy than low velocities design. The effect of size and thickness of reinforcement was studied and the sensitivity of size and thickness was different according to base thickness of model. The optimum size and thickness of the reinforcement has shown a direct proportion to the thickness of base model. Also, the thicker the base model was, the effect of optimization using reinforcement was the bigger. The trend curve for effective size and thickness of reinforcement using response surface method was obtained. The predicted size and thickness of reinforcement by RSM were compared with results of DOE. The results of a specific dynamic mean crushing loads for the predicted design by RSM were shown the small difference with the predicted results by RSM and DOE. These trend curves can be used as a basic guideline to find the optimum reinforcement design for S-shaped member.

• Journal of Engineering Education Research
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• v.19 no.4
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• pp.14-23
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• 2016

This study is to analyze the team interaction in accordance with the team size. Thereby, it is to reveal the team size for the attainment of the effective team interaction and the specific goals to achieve the purpose of this study are as follows. Firstly, the frequency and percentage of team interaction in accordance with the team size are presented. Secondly, the statistical verification of the team interaction in the social emotional area is conducted. Thirdly, the statistical verification of the team interaction in the task area is conducted. In order to do this study, we explain the purpose of study, confidentiality, and withdrawal right were described and then 32 persons who agreed to participate were selected as the subjects for the study. After that, the autonomous organization of team was induced and a total of 8 teams were organized - 3 teams comprised of 3 members, 3 teams of 4 members, 1 team of 5 members, and 1 team of 6 members. Further, Bales' (1950) Interaction Process Analysis (IPA) was used in order to analyze the team interaction, and Mangold INTERACT was used as a coding program. The results of study are as follows. Firstly, the highest frequency of the team interaction showed up in the case of five or six members and the lowest in the case of 3 members. Secondly, a statistically significant difference in the social emotional (positive) area showed up in accordance with the team size and the team organizations of three or four members were effective. Thirdly, a statistically significant value in the answer area showed up in accordance with the team size and the team organizations of five or six members were effective.

• Journal of the Korean Dietetic Association
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• v.26 no.2
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• pp.153-173
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• 2020

The purpose of this study was to objectively quantify the effects of nutrition and dietary life education on preschoolers through meta-analysis. In addition, it provides basic data for the implementation of nutrition education and development of systematic nutrition and dietary life education programs. In this study, a meta-analysis of 27 papers was conducted that conformed to the selection criteria in the study conducted from January 2012 to August 2019 to derive objective data on the effects of education. As a result of the analysis, the overall effective size of nutrition and dietary life education for preschoolers was 0.829, which indicates a strong effect. According to the education method, the effect size of general education was 0.562, which indicates a medium effect size, the vegetable playing-based experience education was 0.685, which indicates a medium effect size, and cooking activity-based experience education was 1.101, which indicates a large effect size. Judging from this result, experience activity education was more effective than general nutrition education. In addition, the combined size of convergence education conducted through a combination of general and experience education was found to be the most effective at 1.301. In terms of educational effect, it was confirmed that the effect size was 0.898 for improving nutrition knowledge, 0.858 for improving dietary habits, 0.836 for improving unbalanced diet, and 0.756 for improving food preference and intake, and the sizes of effects were all found to be large. As frequency of education increased, the number of education participants decreased and the effect of education increased.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.4
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• pp.220-224
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• 2012

The analysis on the bus bar effect is conducted to develop a cost effective 24kV/2,000A switchgear. The temperature enclosures and bus bars could rise due to several heat sources such as eddy current losses and copper losses. Therefore, a study on the characteristics of the electric field intensity and electromagnetic loss according to the bus bar size in a bus bar compartment is essential to design a electrically reliable high voltage switchgear. It is investigated that the electromagnetic influence to the temperature rising and the dielectric stability according to various bus bar sizes by using finite element method(FEM). The electric field intensity and electromagnetic loss according to various bus bar sizes are calculated to design a reliable and a high voltage switchgear. As results, it is found that the electromagnetic loss and the dielectric stability of bus bar could be determined by a bus bar size. It means that a cost effective 24kV/2,000A high voltage switchgear could be developed by selecting the proper size of a bus bar. Also, it is recognized that the electromagnetic characteristics according to various bus bar sizes in order to design an electrically stable high voltage switchgear when the enclosure size is determined as a fixed value. Futhermore, studies on the various nominal voltage class and bus bar sizes will be conducted to develop a cost effective high voltage switchgear.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.2
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• pp.461-472
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• 1996

The relationship between plastic deformation and crystal grain change in warm forging processes of SM10C carbon steel is studied. If the carbon steel is deformed at warm forging temperature(about recrystallization range), material properties are changed due to microstructural chanre of the crystal grain and cementite of the internal part. Some experimental values are investigated in terms of the elliptic degree of cementite, the grain size of cementite and ferrite grain size. When plastic deformation proceeds, the elliptic degree of cementite becomes larger and the grain size of cementite particle becomes small. In addition, the size of ferrite grain becomes fines by recrystallization. The elliptic degree of cementite has a considerable effect on formability. The distribution of effective strain in the forging was calculated by the rigid visco-plastic FEM analysis. The effective strain distribution obtained from the FEM simulation is compared with the experimental result, At the level of effective strain 0.3, dynamic recovery and dynamic recrystallization begin and at the level of over 2.5, the organization of material has better internal structure that is suitable for the following cold forming.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.2
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• pp.3758-3762
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• 1975

In order to find out the optimum size of nozzle of the power sprayer in the paddy field, four different sized hole of nozzles were tested on its discharge volume per unit time and its effective covering distance. 1. The discharge rate of each nozzle is proportional to square root of the transmitted internal pressure of liquid, and the discharge coefficient ranges from 0.82 to 0.86 at the pressure of 20 to 30 kg/$\textrm{cm}^2$. 2. The effective covering distance is increased as the size of the hole is larded and also the pressure is increased under under the limited pressure. Generally, the effective covering distance is not greatly increased at the pressure of above 25kg/$\textrm{cm}^2$. The distance from the nozzle to the spot where the largest amount of droplets are dropped is about 14.5m for 3.05mm nozzle and 16m for 4.05mm nozzle in the pressure range from 20 to 25kg/$\textrm{cm}^2$. 3. From the above results it is concluded that the 3mm nozzle with the power sprayers, which are now being supplied to the farmers, can be used for disease and insect control on the paddy field of which block size is 30m${\times}$100m, and operators need not to enter the field for spraying. For the 40m${\times}$100m block, 4mm nozzle should be used with large size of pump which discharge capacity is 60l/min or more.

• The Journal of Korean Obstetrics and Gynecology
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• v.28 no.1
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• pp.147-157
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• 2015

Objectives: We report two cases that have an effective result with Korean traditional medical treatment to two patients who have uterine fibroids, using transabdominal ultrasonography for checking the size of uterine fibroids. Methods: A 44-year-old patient and a 43-year-old patient were treated with an herbal medicine, acupuncture and cupping therapy. We followed up the symptoms and the size of uterine fibroids. Results: The 44-year-old patient was asymptomatic, her size of the uterine fibroid was reduced for 6 months. Also, the 43-year-old patient experienced that the symptoms such as urinary frequency, ovulation pain, heavy bleeding were improved and the size of the uterine fibroid was reduced. Conclusions: This results suggest that Korean traditional medical treatment if effective for both asymptomatic and symptomatic uterine fibroids and ultrasonography is useful for checking the effect of Korean traditional medical treatment. Further case series and studies are warranted.

• Korean Journal of Metals and Materials
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• v.46 no.10
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• pp.617-626
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• 2008

This study is concerned with the effect of Cu and B addition on microstructure and mechanical properties of high-strength bainitic steels. Six kinds of steels were fabricated by varying alloying elements and hot-rolling conditions, and their microstructures and tensile and Charpy impact properties were investigated. Their effective grain sizes were also characterized by the electron back-scatter diffraction analysis. The tensile test results indicated that the B- or Cu-containing steels had the higher yield and tensile strengths than the B- or Cu-free steels because their volume fractions of bainitic ferrite and martensite were quite high. The B- or Cu-free steels had the higher upper shelf energy than the B- or Cu-containing steels because of their higher volume fraction of granular bainite. In the steel containing 10 ppm B without Cu, the best combination of high strengths, high upper shelf energy, and low energy transition temperature could be obtained by the decrease in the overall effective grain size due to the presence of bainitic ferrite having smaller effective grain size.