• Journal of Astronomy and Space Sciences
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• v.21 no.2
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• pp.141-152
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• 2004

Optics fabrication process for precision space optical parts includes bound abrasive grinding, loose abrasive lapping and polishing. The traditional bound abrasive grinding with bronze bond cupped diamond wheel leaves the machine marks of about $20{mu}m$ rms in height and the subsurface damage of about 1 ${mu}m$ rms in height to be removed by subsequent loose abrasive lapping. We explored an efficient quantitative control of precision CNC grinding. The machining parameters such as grain size, work-piece rotation speed and feed rate were altered while grinding the work-piece surfaces of 20-100 mm in diameter. The input grinding variables and the resulting surface quality data were used to build grinding prediction models using empirical and multi-variable regression analysis. The effectiveness of such grinding prediction models was then examined by running a series of precision CNC grinding operation with a set of controlled input variables and predicted output surface quality indicators. The experiment achieved the predictability down to ${pm}20$ nm in height and the surface roughness down to 36 nm in height. This study contributed to improvement of the process efficiency reaching directly the polishing and figuring process without the need for the loose abrasive lapping stage.

• Journal of agricultural medicine and community health
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• v.41 no.2
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• pp.85-97
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• 2016

Objectives: This study was performed to examine the sugars intake through processed foods and its related factors in college students. Methods: The findings of this study was based on the data obtained from the self-administered questionnaire survey of the sugars intake through processed foods. The self-administered questionnaire survey was conducted among 245 college students between March and April, 2015. Results: The amount of sugars intake through processed foods was 45.9g in male collegians and 47.1g in female collegians. In the bivariate analysis, the amount of sugars intake was significantly different by department of major, current smoking status, subjective health status in female collegians (p<0.05). In the multivariate analysis, the amount of sugars intake was related significantly with current drinking status, sleeping time, degree of depression in male students and student's department of major, current smoking status, whether or not of snack intake in female (p<0.05). Conclusions: The program for college students to decrease the sugars intake through processed foods would be necessary, especially in student of non-health department.

• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.273-279
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• 1992

Position reading devices such as optical encoders are most essential components in numerical control (NC) machines and robots. Fabrication process of optical NC-scales was developed for domestic production. The whole process using photo-lithographic techniques consists of about 10 steps. The process parameters were to be carefully determined through many trial experiments. The scale marks of metal film was printed on a glass substrate. The optimum values of various process parameters were extrilcted. The quality of scale marks was attributed to the each process parameters.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.10a
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• pp.33-34
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• 2008

전통 쪽 염료인 니람 제조원리를 바탕으로 산업적인 쪽 염료 제조공정에 대한 제안과 함께 이와 관련한 몇몇 공정변수를 포함한다.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2002.05a
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• pp.65-70
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• 2002

• Proceedings of the Korean Society of Laser Processing Conference
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• 2005.06a
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• pp.48-52
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• 2005

• Proceedings of the Korean Society of Laser Processing Conference
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• 2001.05a
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• pp.86-91
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• 2001

• Proceedings of the Korean Society of Laser Processing Conference
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• 2000.06a
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• pp.11-14
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• 2000

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.492-498
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• 2017

This study examined the bending performance of high strength and seismic purpose reinforcing bars experimentally with various parameters. For the experimental approach on the bending performance, the specimens were prepared with parameters, such as steel grades, diameters of reinforcing bars, and bending angles of reinforcing bars. Tensile strength tests on the reinforcing bars, the bending tests and re-bending tests, and the second tensile strength tests on the re-bended reinforcing bars were conducted. According to the test results on high strength and seismic purpose reinforcing bars, defects did not appear when the yield strength of the reinforcing bar was 500 MPa or less and the diameter was D13 or less, even when the first bending process was performed with a $135^{\circ}$ bending angle and a $2d_b$ inner radius. The bending performance decreased asthe strength and diameter of the reinforcing bars was increased. In addition, there was no significant difference between the general reinforcing bars and seismic purpose-reinforcing bars.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.1
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• pp.48-57
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• 1995

연삭가공중에 발생하는 트러블의 인식과 처리는 공학적 원리에 입각한 방법과 현장 숙련기술자의 경험적 지식을 바탕으로한 방법이있다. 그러나, 연삭가공은 관계되는 가공변수가 많아, 이들 상호간의 관계를 정량적으로 규명할 수 없어 대부분이 숙련자의 지식에 의존하는 것이 현실정이다. 본 논문은 이와같은 점에 착안하여 원통연삭을 대상으로 현장숙련자가 갖고 있는 경험적이고도 정성적인 지식의 호과적인 활용을 위해 계층분석으로 도입하여 이들이 갖고 있는 노하우를 정량화하고, 아울러 공학적원리를 가미한 연삭가공을 트러블 진단. 처리 시스템을 구축하였다. 또한 시스템 구성에 신뢰성을 높이기 위해 폴트 진단 모델을 도입하였다.