• 한국식품영양과학회지
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• 제27권1호
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• pp.29-34
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• 1998

This study was investigated to know changes of the cell wall components, cell wall degrading enzyme activities and contents of soluble protein of strawberry during ripening and softening. The contents of water soluble substances were slightly increased during ripening, but the contents of alcohol-insoluble substances were not changed. The contents of pectin were not changed at green mature and turning stage, while decreased after mature stage. The contents of alkali-soluble hemicellulose and cellulose were increased during ripening and softening. The contents of water-soluble and saltsoluble protein were not changed, but the content of cell wall protein was slightly decreased during ripening. The content of total protein was increased at turning stage, it is not changed after turning stage. $\beta$-Galactosidase activity was increased during ripening, and pectinmethylesterase activity was decreased at turning. Phenylalanine ammonia-lyase activity was changed up to mature stage, but decreased at overripening stage. Polygalacturonase and cellulase activities were not detected at all of ripening stages.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.309-312
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• 2005

DTM (Diamond Turning Machine) is using for ultra precision manufacturing such as, plastic lens die or aspherical optics. This study is on a design of precision 2-axis stage for DTM. We designed and manufactured a back lash free stage using different weights and measured the positioning accuracy using Interferometer. Also, the 2-D moving accuracy is measured using the high magnification CCD technique. Then, the stage is tested with the machining of spherical and aspherical lens in a DTM with air bearing spindle. It was shown that the back lash free stage is effective for improving the positioning accuracy. Also, positioning control errors in motion control board were able to be found using the proposed stages system.

• 문화기술의 융합
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• 제8권2호
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• pp.53-58
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• 2022

일반적인 가정용 선풍기는 단 하나의 좌우 회전 구간을 갖기 때문에 회전 각도를 조절할 수 없어 불필요한 영역까지 바람이 가거나 바람이 필요한 공간에 바람이 가지 않는 구간이 발생한다. 본 논문에서는 에너지 낭비를 줄이면서 필요한 공간에 선택적으로 바람을 보낼 수 있도록 회전 구간을 효율적으로 조절하는 방법을 제시하고자 한다. 정지 풍향각 측정 실험을 통해 최소 회전 각도를 구하였으며 최적의 회전 단계수를 선정하기 위해 바람이 도달하는 공간을 적절히 분할하였다. 이를 통해 선풍기가 45°의 최소 회전 각도와 3단계의 회전 구간을 가지면서 각 단계마다 정지 풍향각의 2배씩 회전 각도가 증가할 때 바람이 효율적으로 분배되는 것을 확인하였다. 따라서 본 논문에서 제시한 선택적 회전 구간 조절 방법은 선풍기 구조에 큰 변형 없이 에너지 낭비를 최소화 할 수 있을 것으로 사료된다.

• 한국식품저장유통학회지
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• 제5권4호
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• pp.342-345
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• 1998

세포들은 변색기까지는 아주 조밀하게 결합하고 있었으나 완숙기에서는 세포벽 중층이 다소 분해되어 둥근 형태의 세포를 관찰할 수 있었다. 세포벽 변화는 녹숙기에서는 중층을 구별할 수 없을 정도로 세포벽이 발달되지 않았으며 변색기에서는 중층을 관찰할 수 있었고 완숙기에서는 분해되어 완전히 분리되는 것을 관찰할 수 있었다. 세포의 조직은 녹숙기에서는 mitochondria, endoplasmic reticulum 둥의 조직과 소액포를 관찰할 수 있었으나 변색기 이후에는 액포가 발달하면서 cytoplasm과 organelle이 세포벽에 흡착되었다. 세포간극은 녹숙기에서는 형성되지 않았고 변색기에서는 세포간극과 간극 주위에 세포벽 분해현상을 관찰할 수 있었으며, 완숙기에는 중층의 분리와 분해산물이 간극에 분산되어 있는 것을 관찰할 수 있었다.

• 한국수산과학회지
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• 제46권6호
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• pp.970-972
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• 2013

We examined the relative growth of Microstomus achne during early life stages of laboratory-reared larvae and juveniles. Turning points in the relative growth of preanal length and upper jaw length against total length occurred during the settlement period (11.12-19.91 mm in total length). However, turning points in the relative growth of head length and eye diameter, as compared to total length, occurred during metamorphosis (17.57-22.47 mm in total length). Our results suggest that Microstomus achne concentrates its energy on the feeding apparatus (jaw) and digestive organs (intestine) rather than sensory or neural organs (eye, head) during early larval stage growth.

• 한국정밀공학회지
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• 제26권1호
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• pp.82-88
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• 2009

Ultra-precision turning is highly needed to manufacture molds for precision lens. In this study, micro-turning combined with elliptical vibration cutting (EVC), which is known to enhance micro- machining quality, was investigated by installing a rotary stage into the micro-grooving machine. From machining experiments involving materials of copper, brass, and aluminum and single and poly crystalline diamond tools, it was found that EVC produced thinner and curlier chips and that better surface finish could be achieved, compared with conventional turning, owing to prohibition of formation of burrs and built-up edges. Therefore, we found EVC micro turning could be readily utilized to manufacture precision mold.

• 한국생산제조학회지
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• 제4권3호
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• pp.48-57
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• 1995

The feasibility of generating controller surface topographies in single-point conventional turning operations is investigated. First, a mathematical model of the surface generation process was developed. Second, in order to control the texture of the machined surface, a micro-positioning stage and the associated command generation software were designed and built. Experimental examples have shown that surface texture can be precisely controlled and is in good agrement with the theoretical predictions.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1995년도 춘계학술대회 논문집
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• pp.24-33
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• 1995

The feasibility of generating controlled surface topographies in single-point conventional turning operations is investigated. First a mathematical model of the surface generation process was developed. Second in order to control the texture of the machined surface a micro-positioning stage and the associated command generation software were designed and built. Experimental examples have shown that surface texture can be precisely controlled and is in good agreement with the theoretical predictions.

• 중국학논총
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• 제66호
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• pp.161-188
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• 2020

The purpose of this paper is to analyze the debate on the Lewisian turning point in China. Despite the heated debate and accumulating research results both inside and outside China, the results showed a very complex spectrum. Different results were presented depending on which criteria the researcher selected, which analytical tools were used, and which data were utilized. Territory of China is vast, and the differences in economic basement and development stages between regions are not only severe, but also the economic gap among areas in a region is big. Therefore, it is difficult to have a significant meaning in analyzing the Lewisian Turning Point China as a whole. In addition, China's industrial production and labor force structure remain very unbalanced. This can be said to be due to the fact that the allocation and relocation of labor force according to the stage of economic development has not been achieved reasonably, and so it confuses the task of determining whether the Lewis Turning Point has arrived of not.

• 한국기계가공학회지
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• 제18권12호
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• pp.7-14
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• 2019

A marine turning gear controls the position of the piston-crank mechanism by rotating the flywheel of the marine engine at a low speed, which is the main auxiliary machine that enables the disassembly and maintenance of the engine. In this study, the safety factor for surface durability and tooth bending strength was improved by the design modification of the marine turning gear based on the spur planetary gear. Angular velocity, torque, and efficiency of the turning gear were measured using a reliability evaluation tester, and a multibody dynamics model for analysis corresponding to the test results was developed. Finally, it was confirmed that the design improvements improved the tooth surface damage of the sun gear in the 3^rd reduction stage.