• Journal for History of Mathematics
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• v.22 no.1
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• pp.1-24
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• 2009

In this paper we have inferred the influence of Zeno on the construction of the potential infinite of Aristotle based on arguments of Zeno's paradoxes. When we examine the potential infinite of Aristotle as the basis of the ancient Greek mathematics, we can see that they did not permit the concept of the actual infinite necessary for calculus. The reason Why they recognized the potential infinite, denying the actual infinite as seen in Aristotle's physics could be found in their attempt to escape the illogicality shown in Zeno's arguments. Accordingly, this paper could provided one of reasons why the ancient Greeks had used uneasy exhaustion's method instead of developing the quadrature involving the limit concept.

• Advances in materials Research
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• v.8 no.4
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• pp.275-293
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• 2019

The engine parts material used in gas turbines (GTs) should be resistant to high-temperature variations. Thermal barrier coatings (TBCs) for gas turbine blades are found to have a significant effect on prolonging the life cycle of turbine blades by providing additional heat resistance. This work is to study the performance of TBCs on the high-temperature environment of the turbine blades. It is understood that this coating will increase the lifecycles of blade parts and decrease maintainence and repair costs. Experiments were performed on the gas turbine blade to see the effect of TBCs in different combinations of materials through the air plasma method. Three-layered coatings using materials INCONEL 718 as base coating, NiCoCrAIY as middle coating, and La₂Ce₂O₇ as the top coating was applied. Finite element analysis was performed using a two-dimensional method to optimize the suitable formulation of coatings on the blade. Temperature distributions for different combinations of coatings layers with different materials and thickness were studied. Additionally, three-dimensional thermal stress analysis was performed on the blade with a commercial code. Results on the effect of TBCs shows a significant improvement in thermal resistance compared to the uncoated gas turbine blade.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.2
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• pp.101-106
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• 2013

Purpose: As UBC IRMA is being tested, patients out of the reference value are reacting within the value again a few days later the urine collection tested, which causes the reliability of the test to decrease as a result. In this study, we can assume that the physiological changes in the factors would affect the results. The purpose of the study is to find out whether hematuria and proteinuria in the sample as well as the interval time (3 hours or more recommended) have affected the results. As a result, we could discover the changes in factors and increase the reliability of the test. Materials and Methods: 468 people (female: 249, male: 219) who came for the check-up were presented herein for medical examination from 2013.3.15 to 2013.1.2. Some people out of 468 who have reacted onto the reference value were divided into group low titer zone, ow-middle titer zone, and middle-high titer zone and tested for hematuria and proteinuria. During that period, 48 outpatients were asked to fill in a questionnaire regarding the urination interval time. The reagents used were (IDL Biotech AB, Sweden) and UBC IRMA. Results: Of the patients that are formed in the reference value of ($0.1-34.0{\mu}g/L$) turn out to be 52.7 years average age in their low concentration, ($mean{\pm}SD$) of the value of $0.10{\pm}0.02{\mu}g/L$. Among 80 people (50.8%, female: 49.2%), 16 patients (20%) have shown reaction to microscopic hematuria and 10 patients (12.5%) responded to proteinuria. In the average low concentration under 52.5 years of average age, 43 people (53%) have shown reaction to microscopic hematuria and 21 people (26.3%) are proteinuric patients out of 80 patients (male: 50.8%, female: 51.3%). In the middle high concentration of $11.8{\pm}4.82{\mu}g/L$ under the average age 51.7 years, 35 patients (53%) have responded to the microscopic hematuria and proteinuric patients are 26 people (39.3%) out of 66 people (men: 44%, women: 56%). In addition, in the concentration of $51.7{\pm}43.5{\mu}g/L$, some patients who get out of the reference value are observed as the average age of 52.0. 11 patients (78.6%) out of 14 (male: 35.7%, female: 64.3%) react to the microscopic hematuria. There show 6 people (42.8%) who turn out to be as proteinuric patients. As for the interval time, $1.67{\pm}3.71{\mu}g/L$ was the average value among 48 patients (female: 45.8%, male: 54.2%). Conclusion: We cannot see if proteinuria and hematuria directly affect abnormal results of inspection of 8,18 cytokeratin; however, we can find out that they statistically have an influence on highly generating UBC among several mechanisms. Also, although urination interval time was various every 15 minutes, we it does not affect these results.

• Journal of the Korean Chemical Society
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• v.62 no.3
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• pp.214-225
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• 2018

In this study, we tried to find out how heat and thermal energy terms are defined and used in Korean science textbooks, and to see if there are any differences in the meaning of these terms used in different areas of science. For this purpose, the contents of 52 science textbooks of elementary, middle and high school published by the 2009 revised curriculum were analyzed. The definition of the term heat is given in the middle school Science(1) and the high school Physics I and II textbooks. Most textbooks define heat as "energy transferred due to a temperature difference (Type I)". Only one textbook of Physics I defines heat as "transfer of energy due to a temperature difference (Type II)". The definition of thermal energy is mostly presented in the middle school Science (2) and the high school Physics I textbooks. Physics I textbooks define the thermal energy as "molecular kinetic energy (Type III)", while Science(2) textbooks define it as Type I or "energy causes temperature change or phase transition of matter (Type IV)". In the texts of textbooks, heat is mainly used as the meaning of Type I or Type III. Thermal energy is mainly used as Type III, but it is also used as Type I in the high school Physics and Chemistry textbooks. The meanings of heat and thermal energy terms used are differed by the area of science. They are mainly used as type I or type III in Physics and Chemistry textbooks, and used as type III in Life Science and Earth Science textbooks.

• Journal of Magnetics
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• v.19 no.2
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• pp.185-191
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• 2014

In this study we evaluated that flow rate changes affect the (time of flight) TOF image and contrast-enhanced (CE) in a three-dimensional TOF angiography. We used a 3.0T MR System, a nonpulsatile flow rate model. Saline was used as a fluid injected at a flow rate of 11.4 cm/sec by auto injector. The fluid signal strength, phantom body signal strength and background signal strength were measured at 1, 5, 10, 15, 20 and 25-th cross-section in the experienced images and then they were used to determine signal-to-noise ratio and contrast-to-noise ratio. The inlet, middle and outlet length were measured using coronal images obtained through the maximum intensity projection method. As a result, the length of inner cavity was 2.66 mm with no difference among the inlet, middle and outlet length. We also could know that the magnification rate is 49-55.6% in inlet part, 49-59% in middle part and 49-59% in outlet part, and so the image is generally larger than in the actual measurement. Signal-to-noise ratio and contrast-to-noise ratio were negatively correlated with the fluid velocity and so we could see that signal-to-noise ratio and contrast-to-noise ratio are reduced by faster fluid velocity. Signal-to-noise ratio was 42.2-52.5 in 5-25th section and contrast-to-noise ratio was from 34.0-46.1 also not different, but there was a difference in the 1st section. The smallest 3D TOF MRA measure was $2.51{\pm}0.12mm$ with a flow velocity of 40 cm/s. Consequently, 3D TOF MRA tests show that the faster fluid velocity decreases the signal-to-noise ratio and contrast-to-noise ratio, and basically it can be determined that 3D TOF MRA and 3D CE MRA are displayed larger than in the actual measurement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3022-3029
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• 2011

One of the characteristics of the informatics subject implementing the revised national curriculum is to develop the practical attitude of the student as an active member of information society. The purpose of this study is to examine whether the units 'Information Society and IT' in middle school informatics textbooks reflect inquisitive tendencies to student's practice. After four textbooks that were widely selected by schools were selected from among the authorized textbooks, the sentences of the selected textbooks were analyzed by utilizing Romey's analysis method to see whether there was such an inquisitive tendency in them. As a result of analyzing six content elements of the textbooks, one textbook and two textbooks had an inquisitive tendency in three elements or more in terms of texts and activities index respectively. But there was no inquisitive tendency in the textbooks in terms of figure/diagrams, questions at the end of chapters and chapter synthesis. This study is meaningful in that it attempted to make a quantitative analysis of middle school informatics textbooks and to investigate an inquisitive tendency in the textbooks by analyzing every statement and sentence instead of analyzing just some parts of the textbooks.

• Journal of Korean Home Economics Education Association
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• v.10 no.1
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• pp.171-183
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• 1998

The purpose of this study were to see the concept of creativity for the application to the home economics subject and to analyze the home economics textbooks required by the 6th curriculum in a viewpoint of the development of creativity. To achieve these purposes, the learning unit of making necessaries of 8 different home economics textbooks for middle school were compared in the point of titles of learning unit, learning objectives, contents of learning unit, study problems, and exercises. The results of this study were as follows : 1) For the learning objectives, most of home economics textbooks were focused on the basic knowledge and basic skills education rather than the creative thinking and creative problem solving. 2) For the contents of the textbooks, all of home economics textbooks were fixed by the materials and making steps for education of basic skills. So, it was found that the creativity of students could not developed. 3) For the study problems, most of home economics textbooks had some posibility of developing the creativity of students, relatively. 4) For the exercises, most of home economics textbooks had limited posibility of developing the creativity of students.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3163-3167
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• 2014

Background: Breast-conserving surgery (BCS) plus radiotherapy is equivalent to modified radical mastectomy (MRM) in terms of outcome. However there is wide variation in mastectomy rates dependent both on tumour and patient characteristics. Objective: This study aimed to assess the determinants of surgery choice in Asian patients with early breast cancer in a middle-income country. Materials and Methods: 184 patients with early breast cancer treated between Jan 2008 and Dec 2010 were recruited to complete a questionnaire. Chi-square test was used to analyze the association between surgery choice and demographic and tumour factors, surgeon recommendation, family member and partner opinions, fear of recurrence, avoidance of second surgery, fear of disfigurement, interference with sex life, fear of radiation and loss of femininity. Results: 85 (46%) had BCS while 99 (54%) had mastectomy. Age >60, Chinese ethnicity, lower education level, and larger tumour size were significantly associated with mastectomy. Surgeon recommendation was important in surgery choice. Although both groups did not place much importance on interference with sex life, 14.1% of the BCS group felt it was very important compared to 5.1% in the mastectomy group and this was statistically significant. There was no statistical difference between the two groups in terms of the other factors. When analyzed by ethnicity, significantly more Malay and Indian women considered partner and family member opinions very important and were more concerned about loss of femininity compared to Chinese women. There were no statistical differences between the three ethnic groups in terms of the other factors. Conclusions: When counseling on surgical options, the surgeon has to take into account the ethnicity, social background and education level, age and reliance on partner and family members. Decision-making is usually a collective effort rather than just between the patient and surgeon, and involving the whole family into the process early is important.

• Journal of Korea Multimedia Society
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• v.5 no.1
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• pp.38-46
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• 2002

In this paper, we present an adaptive contrast controller for improving the Quality of motion-picture in the video signals on the display. Using a median of image signals, we can improve the contrast according to the middle brightness, adaptively. In addition, the proposed method is useful for real-time image processing and can be composed of simpler hardware structure than other conventional methods because it does not require field and frame memory for computed data. The proposed method can be applied for video signals as well as the still image, while existing methods are confined to only the static image Also, we designed the algorithm through the VHDL, and implemented it through the FPGA. From the testing results, we see that the proposed method can effectively improve the image contrast.

• Journal of Korean Biological Nursing Science
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• v.8 no.1
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• pp.39-48
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• 2006

Purpose: To see the effects of capsaicin on the peripheral nerve damage of intervibrissal fur in mature rats, Method: 24 female mature rats($200{\sim}250g$) are divided to 3 groups and compared with each other. Immunofluorescence dye using CGRP and PGP antibodies was performed and 8 weeks after administration of capsaicin with control group. Result: The immunopositive reaction against PGP and CGRP was reduced by the damage of epidermal and dermal endings in unmyelinated sheath and thin myelinated sheath and the group after 8weeks showed distinct positive reaction of PGP and CGRP than the group after 4 weeks which means the recover of nerves. Conclusion: As a result, capsaicin influenced on pain-related neurotransmitter like CGRP when administerd to mature rats and even though it caused the damages on unmyelinated sheath and thin myelinated sheath, the damaged nerves recovered after 8 weeks. Also the research about sensory nerve endings scattered over middle dermal and deep epidermal layers such as lanceolate, merkel reticular, Ruffini endings should be studied when the research of the inner conical body is performed. Further studies are necessary about the toxicity and effect of capsaicin on the peripheral nerve endings.