• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.86-89
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• 2005

Design and estimation of a spindle system which was composed of grinding spindle and regulating spindle for the centerless grinding of ferrule was performed and prototypes of each spindle were manufactured. Loop stiffness of the spindle system was 130 N/${\mu}m$. Although the value was lower than the target value of 150 N/${\mu}m$, as there included 20% of the safety factor, it was enough to machine the ferrule. Rotational accuracies of each spindle were about 0.2${\mu}m$ at the primary speed of 2,300 rpm(grinding spindle) and 300 rpm(regulating spindle). Temperature rises at the same speed were about $4.4\;\~\;4.7^{\circ}C$ in the case of grinding spindle and $1.8^{\circ}C$in the case of regulating spindle, which were well agreed with the designed value. From these results, it was estimated that the prototype of spindle system had a enough performances for the centerless grinding machine to machine the ferrule.

• Asian Journal of Innovation and Policy
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• 제6권2호
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• pp.152-169
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• 2017

In this paper, we analyze the basic research system in South Korea. We propose a national basic research system consisting of value, openness, input, transformation, and output. Based on this framework, we set up interview questionnaires, and 15 key informants have been interviewed. According to our results, first, in terms of value, basic research is recognized as an activity for creating knowledge in the understanding of nature. Second, as for openness, scientists and policy experts agree that active interaction with the global community is an important value for the national research system. Third, in terms of sustainable research resources, scientists are strongly required to effectively allocate research funding, maximizing the creativity of researchers and the efficient sharing of research equipment. Fourth, in transformation, basic researchers maintain that the Korean research system has is extremly dependent on the government's external control, and its self-regulative system has been weak for over half century onw. Fifth, for global competitiveness, the interviewees agreed that the quality of basic research in Korea is approaching that of its global competitors. Finally, we put forward some policy implications on the basis of these findings.

• Physical Therapy Rehabilitation Science
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• 제8권3호
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• pp.152-157
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• 2019

Objective: We aimed to investigate differences of range of motion in measuring shoulder internal rotation (IR) and external rotation (ER) resulting from posture change in manual scapular stabilization in prone, hook-lying, sitting, and standing positions in healthy young adults. Design: Cross-sectional study. Methods: This study included healthy young adults who agreed to participate after a thorough explanation about the study purpose and methods. A clinometer was used to measure shoulder rotation. Measurements of shoulder rotation according to postural change were performed in prone, hook-lying, sitting, and standing positions. The repeated measures analysis of variance was used to compare between-group differences in postural change. Results: The lower the posture, the greater the average value of IR angle. In contrast, the higher the posture, the greater the average value of the external rotation angle. In active and passive IR with posture change, there was difference in average value but with no statistical significance. In active and passive ER, there was a statistically significant difference between prone and sitting, prone and standing, hook-lying and sitting, hook-lying and standing, and sitting and standing position (p<0.05). Conclusions: Our findings suggest that postural change should be considered in order to increase the strength or range of motion of the internal and external rotation of the patient's shoulder joint.

• 분석과학
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• 제23권6호
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• pp.524-530
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• 2010

클로람페니콜은 미생물과 박테리아들의 활동을 억제시킴으로써 동물 치료에 효과적인 축산 항생제 중의 하나이다. 그러나 사람에게 재생 불량성 빈혈과 같은 치명적인 부작용이 발생하여 식용으로 사육하는 동물들에 대한 클로람페니콜의 사용을 유럽을 포함한 많은 나라에서 금지하였다. 본 연구에서는 돼지고기 시료 중 클로람페니콜을 분석하기 위하여 동위원소희석 액체크로마토그래피-질량분석법(IDLC/MS/MS)을 이용하여 정확하고 정밀한 정량분석을 하였다. 돼지고기 시료중의 클로람페니콜은 에틸아세테이트로 추출하였으며, 회수율을 높이기 위하여 고체상 추출법(Solid Phase Extraction)을 이용하였다. 액체크로마토그래피/질량분석기는 전기 분무 이온화 장치(Electrospray Ionization, ESI)를 장착하여 음이 온 모드로 선택반응분석법(Selected Reaction Monitoring mode)에서 수행하였다. 클로람페니콜의 분자이온 $[M-H]^-$이온이 조각이온인 $[M-H-(HCOCl)]^-$로 가는 m/z 321 ${\rightarrow}$ 257와 동위원소의 m/z 326 ${\rightarrow}$ 262 채널을 선택하여 분석하였다. 클로람페니콜을 약 0.2, 1, 10, $25\;{\mu}g$/kg의 농도가 되도록 첨가한 돼지고기 시료로부터 제조값과 측정 분석값을 비교하여 검토한 결과, 측정값들은 불확도 범위 내에서 제조값과 일치함을 보였다. 또한 IRMM(Institute for Reference Materials and Measurement)의 클로람페니콜 분석용 돼지고기 시료인 인증 표준물질 BCR 445를 분석한 결과, 본 실험의 측정값은 불확도 범위 내에서 인증값과 일치함을 보였으며 불확도의 경우에는 IRMM이 제공한 값보다 훨씬 향상된 값을 보였다.

• 가정과삶의질연구
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• 제33권6호
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• pp.77-95
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• 2015

The purpose of this study was to examine the value of children in South and North Korea and to identify the similarities and differences in value orientations related to children and curriculum in child-care and education. The secondary data including 2013 research report on the South Korean consciousness and values, the Familial Law Act and the Child Welfare Act of South Korea, the Familial Law Act and the Law of Nursing and Upbringing of Children in North Korea, and a series of Choson-yeosung magazines in North Korea were analyzed. Results showed that first, it was common that both of social and psychological values of children were found, but the psychological values were more prevalent in the South and the social values were more dominant in the North. Second, parents in both cultures publically agreed that parenting should promote the development of the whole child. However, parents in the South were inclined to support happiness and personal achievement of children, whilst parents in the North were likely to reinforce ideology education producing a pillar for socialism. Third, it was common that both parents of the South and the North were primarily responsible for child-rearing, but the role of government in child-rearing was more emphasized in the North. Lastly, supporting daily routine activities, communication skills, and art activities were included in child-care and education programs in both cultures. However, communication skills and social relationship were emphasized in programs of the South, whilst ideology education was the most important components in program of the North. The strategies for understanding differences in the value of children between the South and the North after unification were discussed.

• 대한가정학회지
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• 제36권8호
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• pp.105-122
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• 1998

This research investigated the relationships between families' environment, familism, and the agreement on the parent-child relations as depicted in Korean proverbs to find the change of the traditional values about parent-child relationships. The sample was comprised of 474 Korean married people. They were asked to rate the degree to which they agreed on the underlying value of each proverb. The data were collected through a mailed questionnaire and interview. The findings indicated that the responses of subjects varied as a function of families' environment and familism variables. More specifically, while the subjects living with extended family were more likely to rate the value toward children and daughter high, the subjects from nuclear family were more likely to express the affection toward children, to prefer boys, and to express child-rearing stress. In addition, the people who had lived with grandparents together tended to agree with the value of filial piety. The respondents from conservative surroundings were more likely to express the affection toward children and to prefer boys. The subjects from a rural community tended to prefer boys and to place high value on the authoritative control. The people who supported familism tended to express the affection toward children and child-rearing stress, to prefer boys, and to agree with the filial piety and authoritative control. But they tended to rate low on the value of children and daughter.

• International Journal of Fluid Machinery and Systems
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• 제8권3호
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• pp.155-168
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• 2015

No-load speed is an important performance factor for the safe operation of hydropower systems. In turbine design, the manufacturers must conduct several model tests to calculate the accurate value of no-load speed for the complete range of operating conditions, which are expensive and time-consuming. The present study presents steady and unsteady methods for calculating no-load speed of a Francis turbine. The steady simulations are implemented using a commercial flow solver and an iterative algorithm that relies on a smooth relation between turbine torque and speed factor. The unsteady method uses unsteady RANS simulations that have been integrated with a user subroutine to compute and return the value of runner speed, time step and friction torque. The main goal of this research is to evaluate and compare the two methods by calculating turbine dynamic parameters for three test cases consisting of high and medium head Francis turbines. Overall, the numerical results agreed well with experimental data. The unsteady method provided more accurate results in the opening angle range from 20 to 26 degrees. Nevertheless, the steady results showed more consistency than unsteady results for the three different test cases at different operating conditions.

• 한국생산제조학회지
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• 제26권4호
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• pp.365-370
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• 2017

In this article, a 20 kHz Titanium (Ti) ultrasonic waveguide system for a nano-surface reformation process was designed and fabricated. First, finite element analysis using ANSYS software was performed to find the optimal dimensions. The obtained anti-resonance frequency for the Ti transducer with the piezoelectric device was 20.0 kHz, which value agreed well with the experiment result of 20.1 kHz (0.5% error). To test the system, chromium molybdenum steel (SCM) 435 was chosen as a test-piece. The result proved that the reformed depth was $36{\mu}m$. In addition, hardness was measured before and after the process. The value was changed from 14 HRC to 21 HRC, which is 50% increasing rate. Finally, the friction coefficient test result showed that the surface coefficient was reduced from 0.14 to 0.10 (28.6% reduction). Based on the results, the Ti ultrasonic equipment is regarded as a useful device for nano-scale surface reformation.

• Journal of Pharmaceutical Investigation
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• 제21권1호
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• pp.23-32
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• 1991

Dissolution profiles of ketoconazole in solid dispersion system (SDS) were investigated in the second fluid (pH 6.8) for the dissolution test (KPV). PVP K-30 and methyl cellulose were used as carriers in SDS, and chloroform as a solvent. Computer optimization technique was applied to obtain an optimum formula of SDS, and the following results were obtained; 1) Dissolution rate of ketoconazole in SDS was larger than that of pure ketoconazole in the second fluid of pH 6.8. 2) PVP K-30 and methyl cellulosr were good carriers for SDS of ketoconazole. Moerover PVP K-30 was better than methyl cellulose. 3) The optimum formula of ketoconazole SDS obtained from computer optimization technique was chloroform 175 ml, PVP K-30 5g and methyl cellulose 0.2g per 1g of ketoconazole. 4) The experimental value of $A_{60}$ (Amount released from ketoconazole tablet during 60 minutes) obtained from SDS by optimum formula agreed well with the value calculated by polynomial regression equation.

• Journal of Microbiology and Biotechnology
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• 제13권3호
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• pp.378-384
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• 2003

Mesophilically-grown granular sludge seeded in thermophilic UASB reactor was monitored to better understand the start-up process of the reactor. The reactor was fed with a synthetic wastewater containing glucose. As COD loading rate increased stepwise, methane production rate increased. Maximum values of COD removal efficiency (95%) and methane production rate (5.3 l/day) were achieved by approximately day-80 and remained constant afterward. However, physicochemical and microbial properties of granules kept changing even after day-80. Specific methanogenic activity (SMA) was initially negligible, and increased continuously until day-153 and remained constant afterward, showing the maximum value of $1.51{\pm}0.13\;g\;CH_4-COD/g$ VSS/day. Deteriorated settling ability of granules recovered the initial value by day-98 and was maintained afterward, as determined by sludge volume index. Initially reduced granule size increased until day-126, reaching a plateau of 1.1 mm. Combined use of fluorescence in situ hybridization and confocal laser scanning microscopy (CLSM) allowed to localize families of Methanosaetaceae and Merhanosarcinaceae in granules with time Quantitative analyses of CLSM images of granule sections showed abundance patterns of the methanogens and numerical dominance of Methanosaeta spp. throughout the start-up period. The trend of SMA agreed well with abundance patterns of the methanogens.