• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.441-442
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• 2007

• 한국기계가공학회지
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• 제15권5호
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• pp.109-116
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• 2016

Polymethyl methacrylate is commonly used in the outer lens of automotive rear lamps. However, if the lens warps above the allowable limit, it may lead to faulty connection with the housing, and failure of the assembly. This study investigated the effects of gate diameter and cooling line distance in the mold design for automotive outer lens. The optimal gate diameter and cooling line distance to minimize the warp of the outer lens were derived as 3.0 mm and 50-60 mm respectively, and the cooling temperature to minimize warp was shown to be $60-80^{\circ}C$ (mold surface temperature $48-67^{\circ}C$). A higher cooling temperature may somewhat mitigate the warp, but is undesirable because it may cause injection molding problems, such as sinks. A mold was constructed matching the optimal design and the produced lens properties, particularly the degree of warp, were comparable with the CAE predictions.

• 한국군사과학기술학회지
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• 제14권3호
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• pp.345-352
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• 2011

This paper focuses on the properties analysis of 9mm bullet dual structure core to substitute current lead core by environment-friendly combination of W-Cu-Ni system high density composite materials. So the four combination samples were made of dual core with the different center of gravity location backward or forward compare to that of lead type bullet, and we experimented about the performance of 9mm bullet dual structure core. In the experimental results, the outer shape of core of four environment friendly samples on the target maintain marginally, while the current lead core bullets are completely crushed after hitting the target. The penetration depth of environment friendly samples excel seven times to lead type bullet and the three out of four samples with forward adjusted center of gravity penetrate deep as twice as ones backward. The impact tolerance of all four samples satisfies military specification, however, more firing tests are required to improve reliability of scattering distribution.

• 한국환경생태학회지
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• 제16권3호
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• pp.233-238
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• 2002

비둘기 깃털을 이용하여 섬지역(경기도 덕적도), 도심지역(서울), 공단지역(여천, 안산, 울산, 부산)의 납 오염 수준을 모니터링 해본 결과, 깃털의 평균 납 농도는 섬지역이 2.55 $\mu\textrm{g}$/wet g, 도심 지역이 4.99 $\mu\textrm{g}$/wet g, 공단지역이 3.08~9.01 $\mu\textrm{g}$/wet g, 으로 각 지역간에 유의한 농도 차이가 있는 것으로 조사되었다(p<0.05). 다만, 여천 공단의 경우 다른 공단에 비해 상대적으로 낮게 나타났으며 섬지역과 비슷한 수준의 납이 검출되었다. 이러한 각 지역간 깃털의 납 농도는 대기오염 농도와도 비슷한 경향을 보이는 것으로 나타났다. 납 농도가 비교적 낮은 덕적도와 여천 공단의 경우 간과 깃털 조직간에 정의 상관관계가 있는 것으로 밝혀졌지만(p<0.05) 그외의 지역에서는 상대적으로 간 농도에 비해 깃털의 농도가 높았으며, 두 조직간에 상관관계가 없는 것으로 조사되었다(p>0.05) 이와 같은 결과는 덕적도와 여천 공단지역의 깃털 중 납의 대부분은 체내 조직으로부터 깃털로 이행되어진 것으로 판단되지만, 그 외 지역에서는 체내 조직에서 깃털로 이행된 양보다는 외부로부터 깃털에 부착된 양이 더 크다는 것을 시사한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.529-530
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• 2011

10본의 선재로 각각 구성되는 내층과 외층을 지니는 2층 원��형 도체를 제작하여 그에 대한 교류손실을 측정하기 위하여, 각 층에 전압리드(inner-lead, outer-lead)들을 부착하였으며, 이로부터 픽업된 층 전압과 층 전류로부터 각 층의 손실을 평가하였다. 그 결과를 요약하면, 외층 전류가 내층의 1/2임에도 불구하고 내 외층의 손실은 거의 일치하였다. 또한 내 외층의 전류가 일치한 경우에도 외층 손실은 내층보다 대단히 크다. 이들 결과는 외층은 내층 전류로부터 발생되는 외부 자장하에 있어 외층의 자장이 증가된 것으로 사료된다.

• 한국안전학회지
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• 제20권3호
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• pp.1-8
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• 2005

The industrial induction motor is widely used in the rotating electrical machine for the transmission of power. It is very reliable equipment, but it could lead to the loss of production and lift when failure occurs. Therefore, the failure data is acquired and analyzed by attaching an exclusive instrument to existing induction motor. However, these instruments could lead to side effects, increasing the production costs, because they are very expensive. The purpose of this study is the development of an induction motor bearing failure diagnosis system constructed using LabVIEW which can be supplied the kernelled function, process monitoring and current signature analysis. In addition, the availability and reasonability of the constructed system was examined for an induction motor with failure defects in outer raceway and ball bearing. From the results, it shows that failure diagnosis system constructed is useful for real-time monitoring with detection of bearing defects over the web.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.128-131
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• 2003

In a design of LNG storage tank, one of the major loading conditions that significantly affects liquid tightness of the outer concrete wall is the cryogenic temperature of LNG under the emergency condition of LNG leakage. Proposed in this study are the more consistent procedures to ensure the liquid tightness of LNG tank focusing on the design of prestressing tendon. It is expected that the proposed schemes lead to a more effective serviceability design of LNG tank that satisfies various requirements for the liquid tightness in an efficient manner.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 2010년도 춘계국제학술대회
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• pp.5-12
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• 2010

With a sample of 147 Korean small and medium size companies, this study examined the relationships among degree of information orientation, corporate culture, degree of information management implementation and selected business performances in the process of implementing IMS improvement programs, such as IMS(Information Management System). Information orientation is defined as company-wide understanding and implementation of the underlying philosophy, principles, approached, and tools of information improvement programs. It is assumed that successful implementation of information improvement programs requires a information-oriented mind-set of the employees. The key elements of information orientation include continious improvement structured processes, organixation-wide participation and customer-focused spirit. Culture id defined as the value and beliefs of em organization that shape its behavior. It is also assumed that successful implementation of information improvement programs require strong support from s corporate culture that emphasizes cintinious improvement. Adopting the competing values model of Quinn and McGrath(1985), corporate culture is classified into 'flexible' versus 'controlled culture' and 'outer-directed' versus 'inner-directed culture'. Fitness was defined through the relationship between levels of information oriented and types of corporate culture. The results were as follows. First, it was found that when a company with high information orientation promoted information innovation programs, such as IMS, it reported higher degree of information management implementation and improvement in business performances. Second, the results showed the importance of 'flexible culture' and 'outer-directed culture' in performing information, innovation. Regarding the types of corporate culture, the analysis found that developmental culture, rational culture and group culture were effective. Third, companies with high information oriented and flexible culture or companies with high information orientation and outer-directed culture reported the highest implementation in Information management activities. Fourth, the results showed that the level of information management implementation had a mediating effect on the relationship between information orientation and business performance. It was also found that enhanced non-financial performance led to the improvement of financial performance. This study attempted to exaime the factor that lead information management program to success. In order to reach success, first, it is suggested that companies have positive mind set toward continious information improvement. Secondly, it is recommended that a flexible and outer-directed culture appropriate for continious information improvement is cultivated.

• Structural Engineering and Mechanics
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• 제64권2호
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• pp.195-204
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• 2017

Analytical and experimental studies of the innovative pipe in pipe damper have been recently investigated by the authors. In this paper, by adding lead or zinc infill or slit diaphragm inside the inner pipe, it is tried to increase the equivalent viscous damping ratio improving the cyclic performance of the recently proposed multi-level control system. The damper consists of three main parts including the outer pipe, inner pipe and added complementary damping part. At first plastic deformations of the external pipe, then the internal pipe and particularly the added core and friction between them make the excellent multi-level damper act as an improved energy dissipation system. Several kinds of added lead or zinc infill and also different shapes of slit diaphragms are modeled inside the inner pipe and their effectiveness on hysteresis curves are investigated with nonlinear static analyses using finite element method by ABAQUS software. Results show that adding lead infill has no major effect on the damper stiffness while zinc infill and slit diaphragm increase damper stiffness sharply up to more than 10 times depending on the plate thickness and pipe diameter. Besides, metal infill increases the viscous damping ratio of dual damper ranging 6-9%. In addition, obtained hysteresis curves show that the multi-level control system as expected can reliably dissipate energy in different imposed energy levels.

• 자연과학논문집
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• 제5권2호
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• pp.19-24
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• 1992

대전시 도로변의 대기오염 정도를 알아보기 위하여 주요 간선도로변, 외곽의 도로변 및 보문산의 가로수 중 버즘나무 (Platanus orientalis), 은행나무 (Ginkgo biloba) 및 백합나무(Lirodendron tulipifera) 를 선택하여 그 수피내의 납과 카드뮴의 축적량을 측정하고 교통량과의 관계를 분석하였다. 수피내의 납 축적량은 가로수의 수피에서는 2-1109ppm 으로 보문산 지역의 수피내의 함량이 5-11ppm 인데 비하여 지역에 따라 차이도 심하고 농도가 높았다. 또한 교통량과의 관계는 차량통행량의 증가에 따라, 특히 병목 현상이 심한 지역에서 납의 함량이 높게 나타났는데, 차량 통행량 증가에 따라 수피내의 중금속의 최대 축적량이 비례적으로 증가하였다. 이에 비하여 가로수 수피내의 카드뮴 축적량은 보문산 수피내의 축적량보다 다소 높았으나 변이가 적게 나타났다.