• Journal of dental hygiene science
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• v.9 no.3
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• pp.339-344
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• 2009

The purpose of this study was to examine the knowledge of some adults about oral hygiene devices and their use of the oral hygiene devices. After a survey was conducted from December 3 to 17,2007, the answer sheets from 352 respondents were gathered. and the collected data were analyzed with a SPSS Ver. 17.0 program. The findings of the study were as follows. 1. Concerning the level of knowledge, the adults investigated knew the best that a toothbrush should be kept by making the head upward (76.77). On the other hand, they had little knowledge on water pick, tongue cleaner and interdental brush. 2. As for the level of use, they scored highest on keeping their toothbrushes by making the head upward(76.77), In contrast, they scarcely put water pick, electronic toothbrushes, tongue cleaner to use. 3. Knowledge impact of general characteristics involving mate(62.54). 50s over(66.28) and up, four family members(61.54), graduate school graduate(66.78), self-employed and, professionals(63.63), income of 1 to 1.5 million won(66.66), fathers were smokers(51.89) got the highest marks with a mean. 4. Use impact of the general characteristics female(47.70), 40s over 49s under(47.78), four family members(48.18), graduate school graduate(50.17), professionals(49.79), income of 1 to 1.5 million won(51.89), fathers were smokers(48.10) got the highest marks with a mean.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.3
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• pp.52-59
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• 2001

In this study, a technique has been developed to analyze the performance of the launching system using a gas generator of solid propellant. The physical model which described the thermodynamic behaviors of all launching devices from gas generator to canister and the dynamic behavior of missile was established, applying the empirical coefficients in the heat loss model. The processes of combustion, flow, and heat transfer inside the chamber of gas generator and the launching system were simulated by numerical method. The theoretical analysis guided the optimal design of gas generator and system, which made the launching system satisfy the requirements of good performance and high reliability.

• Transactions of the KSME C: Technology and Education
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• v.1 no.1
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• pp.13-19
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• 2013

Ftheta Lens, whose image height is proportional to its field view angle, is one of the most important parts in Laser Scanning Unit(LSU). In this paper $f{\theta}$ lens design, mold production and modification method of lens design and mold are introduced. Lens design was carried out with Zemax and Special Toric surfaces were applied for lens surfaces to minimize distortion both in main and sub scanning directions. And a high precision machine with 1nm resolution was used to fabricate lens mold cores. After injection the lens was evaluated and the difference from design was examined. This difference was compensated by modifying lens design and new lens mold cores were made according to modified lens design to obtain the quality of original design.

• Journal of the Korean Society for Precision Engineering
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• v.5 no.2
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• pp.7-14
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• 1988

작업물(Work)을 기계에 장입출, 가공에 필요한 공구류의 공급 등이 완전 자동화 된 기존의 사출성형기 Series를 제조하는 FA Systme은, MAP 대응의 FA System 으로 개량되었다. 이 논문은, MAP 대응 새 FA 시스템의 MAP에서 분산.통괄의 역할을 하도록 개발된 Cell controller의 정보관리기능 가운데 하나의 응용으로서 제조공정을 자동적으로 Scheduling 하는데 Expert 시스템(전문가시스템)을 적용한 idea를 소개하는 것이다. 이 idea의 적용 으로 인하여 제조공정의 scheduling 작염은 종래의 주단위로 부터 일일단위의 작업으로 처리가 가능해졌고, 또, 공구수명관리기능의 부가로 무인운전시의 기계의 가공율도 종래보다도 녹일 수가 있었다.

• 연구논문집
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• s.25
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• pp.5-12
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• 1995

Mold platen are one of the most important structural components of the injection molding machine. Mold platen had been designed, and manufactured based on the experience and the method of trial and error. Recently, as the computer progress, the numerical simulation method using commercial finite element analysis code has been used to analyze the characteristics of components. It's a urgent problem to reduce the weight of mold platen while preserving the safety and reliability for the structual failure. Finite element analyses to establish basic design technologies and reducing the weight of mold platen were carried out. As result, we are obtained the about 10% reducing the weight for mold platen.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.543-544
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.479-480
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• 2007

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.76-81
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• 2004

Injection molding is the most widely used process fir the industrial forming of plastic articles. During an injection molding process of composites, the fiber-matrix separation and fiber orientation are caused by the flow of molten polymer/fiber mixture. As a result. the product tends to be nonhomogeneous and anisotropic. Hence, it is very important to clarify the relations between separation orientation and injection molding conditions. So far, there is no research on the measurement of fiber orientation using image processing. In this study, the effects of fiber content ratio and molding condition on the fiber orientation-angle distributions are studied experientially. Using the image processing method, the fiber orientation distribution of welding pars in injection-molded products is assessed. And the effects of fiber content and injection mold shapes on the fiber orientation in case of fiber reinforced polymeric composites are studied experimentally.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.778-784
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• 2001

Injection molding is a very important industrial process for the manufacturing of plastics objects. During an injection molding process of composites, the fiber-matrix separation and fiber orientation are caused by the flow of molten polymer/fiber mixture. As a result, the product tends to be nonhomogeneous and anisotropic. Hence, it is very important to clarify the relations between separation orientation and injection molding conditions. So far, there is no research on the measurement of fiber orientation using image processing. In this study, the effects of fiber content ratio and molding condition on the fiber orientation-angle distributions are studied experimentally. Using the image processing method, the fiber orientation distribution of weld-line parts in injection-molded products is assessed. And the effects of fiber content and injection molding conditions on the fiber orientation functions are also discussed.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.1
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• pp.73-80
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• 2005

Injection molding is the most widely used process for the industrial forming of plastic articles. During an injection molding process of composites, the fiber-matrix separation and fiber orientation are caused by the flow of molten polymer/fiber mixture. As a result, the product tends to be nonhomogeneous and anisotropic. Hence, it is very important to clarify the relations between separation orientation and injection molding conditions. So far, there is no research on the measurement of fiber orientation using image processing. In this study, the effects of fiber content ratio and molding condition on the fiber orientation-angle distributions are studied experimentally. Using the image processing method, the fiber orientation distribution of welding parts in injection-molded products is assessed. And the effects of fiber content and injection mold shapes on the fiber orientation in case of fiber reinforced polymeric composites are studied experimentally.