• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.922-928
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• 2010

There is a little information on the effect of calcium cloride ($CaCl_2$) which is used as deicing salt in Korea on the physiological responses of the street trees. Prunus sargentii is one of the most widespread tree species of street vegetation in Korea. In this study, the effect of $CaCl_2$ on photosynthetic apparatus such as chlorophyll fluorescence image and light response curve of P. sargentii in relation to their leaf and root collar growth responses were investigated. To study the effect of $CaCl_2$ treatment in the early spring, we irrigated twice in rhizosphere of P. sargentii (3-year-old) planted plastic pots with solution of 0.5%, 1.0%, 3.0% $CaCl_2$ concentration before leaf expansion. Results after treatments, total chlorophyll contents and the chlorophyll a/b, photosynthetic rate, quantum yield, dark respiration decreased with increasing $CaCl_2$ concentration. On the contrary, light compensation point increased with increasing $CaCl_2$ concentration. Through the linear regressions of correlation of photosynthetic rate with photosynthetic parameters (quantum yield, dark respiration and light compensation point), we found a significant relationship (p<0.05) between photosynthetic rate and quantum yield and light compensation point except dark respiration. Calcium cloride ($CaCl_2$) induced inhibition of photochemical efficiency ($F_v/F_M$) and non-photochemical quenching (NPQ) were found in treatments of $CaCl_2$, and these reduction rates between control and CaCl2 treatments were drastically showed at 80 days. We suggest that physiological activities are limited from treatment of $CaCl_2$. These reductions of photosynthetic apparatus ability caused eventually the reduction of leaf and diameter at root collar growth.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.24-29
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• 2005

본 연구는 최근 서울시를 중심으로 진행되고 있는 도시 가로조명의 광원교체에 따른 조명환경 개선효과를 조사 분석하였다. 조사대상은 이미 기존의 나트륨램프를 고효율 메탈할라이드 램프로 교체한 서울시 종로구의 창경궁길로 선정하였다. 평가방법은 조사대상을 중심으로 야간의 교체 전, 후의 조명현황조사 및 물리량을 측정하였으며, 이를 토대로 개선효과를 분석하였다. 분석결과, 광원을 교체한 후 수평면 조도는 약 1.4배, 스칼라 조도는 약 1.3배 증가하였으며, 공간의 평균 휘도값은 $0.06cd/m^2$ 증가하였다. 색온도는 2,399[K]에서 3,632[K]로 증가하여 공간의 느낌이 따뜻한 느낌에서 차가운 느낌으로 변화되었는데, 이는 기존의 평온한 이미지에서 부드러운 이미지로 변화 된 것으로 분석된다. 색도는 주황색에 가까운 노란색에서 엷은 노란색을 띠는 백색으로 변화되었으며, 이는 램프의 연색성에 의하여 사물의 식별성에 대한 가시도가 증가한 것으로 분석된다. 또한, 에너지 절감형 친환경 메탈할라이드 램프의 교체에 의하여 앞으로 연간 에너지 절감효과도 클 것으로 기대된다.

• Korean Institute of Interior Design Journal
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• v.17 no.1
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• pp.69-76
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• 2008

The purpose of this study is to analyze the interior characteristics of the Yale center for British art by Louis I. Kahn. As his last realized project, the Yale center for British art shows Kahn's latter architectural thoughts about exterior/interior, space/structure and theory/practice. Kahn arranged unit space(room) around two interior courts and laminated them vertically. This spatial configuration is the result of solving the urban context which needed the continuity of street and complicated program including art museum, retail shop, studio and library. Although Kahn adpted severe formal configuration, he added changes to spatial relation. The visualization of architectural system is realized by revealing the relation of the unit space and structure. And this emphasized the presence of the center. The emphasis of tectonic expression is also the characteristics of interior in that structure is the logical part of whole building system rather than concealing object for the exterior of buildings. In the Yale center for British art, interior characteristics are summarized as spatial configuration based on the relation between unit space and two courts, the visualization of structural order, and the relationship between structure and light.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6006-6012
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• 2012

General solar street light system needs two separate power supply for charging the battery and driving LED Lamp. In this study, one power supply is used for both charging battery and driving LED lamp. In particular, in order to increase the efficiency of the equipment, (maximum power point tracking: MPPT) was applied which is widely adopted in grid-connected solar systems. LED driver embodied using current control routine of charger into Essential constant current system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.569-575
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• 2011

Since the high heat generation of LED chips can cause a reduction in lifetime, degradation of luminous efficiency, and variation of color temperature, studies have been carried out on the optimization of LED packaging and heat sinks. Recently, LED packages have been applied to high-power lights such as car headlamps or street lights, and it is known that cooling using only free convection is not at all efficient. Thus, in this study, a heat pipe with forced convection was examined for the optimization of the cooling performance in high-power LED lights. In addition, optimal on-off control of a fan was adopted to increase the fan lifetime, since the lifetime of the fan is generally shorter than that of the LEDs.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.609-613
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• 2005

Advanced mobile communication devices require a bright, high information content display in a small, light-weight, low power consumption package. In this paper we will outline our progress towards developing such a low power consumption active-matrix flexible OLED ($FOLED^{TM}$) display. Our work in this area is focused on three critical enabling technologies. The first is the development of a high efficiency long-lived phosphorescent OLED ($PHOLED{TM}$) device technology, which has now proven itself to be capable of meeting the low power consumption performance requirements for mobile display applications. Secondly, is the development of flexible active matrix backplanes, and for this our team are employing poly-Si TFTs formed on metal foil substrates as this approach represents an attractive alternative to fabricating poly-Si TFTs on plastic for the realization of first generation flexible active matrix OLED displays. Unlike most plastics, metal foil substrates can withstand a large thermal load and do not require a moisture and oxygen permeation barrier. Thirdly, the key to reliable operation is to ensure that the organic materials are fully encapsulated in a package designed for repetitive flexing. We also present progress in operational lifetime of encapsulated T-PHOLED pixels on planarized metal foil and discuss PHOLED encapsulation strategy.

• 전자공학회논문지 IE
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• v.48 no.2
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• pp.12-18
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• 2011

In this paper, did numerical simulation to confirm LED module for lighting and protection against heat special quality of heat sink device. Analysis was gone dividing on case that emitting light side turns normalcy department considering that eat of device according to usage and case that turn down looking being street lamp of 200 W or security appointment lighting device analysis case, and also, volume of thermal element divides on big case and small case and analyzed. Confirmed that can do so that may discharge LED's thermal value to outside enough in analysis wave and current heat sink shape, and investigated that difference of protection against heat performance according to position of device and size of thermal element appears.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.6
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• pp.641-647
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• 2014

Stand-alone PV systems and grid-connected distribution lines operating independently with out the advantage that it is simple, and construction equipment, but the advantage of less expensive MPPT converter and production, including the energy stored in the battery charging circuit and battery for managing circuitry is required. The use of existing alternative energy in the form of combined-cycle power generation than the one adopted by the form, but primarily solar / wind power system to optimize complex to design and improve the ability to install a battery that canrationalize the price you need an integrated control system be.

• Journal of the Semiconductor & Display Technology
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• v.14 no.3
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• pp.13-22
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• 2015

LED (Light Emitting Diode) lighting is gaining more and more market penetration as one of the global warming countermeasures. LED is the next generation of fusion source composed of epi/chip/packaging of semiconductor process technology and optical/information/communication technology. LED has been applied to the existing industry areas, for example, automobiles, TVs, smartphones, laptops, refrigerators and street lamps. Therefore, LED makers have been striving to achieve the leading position in the global competition through development of core source technologies even before the promotion and adoption of LED technology as the next generation growth engine with eco-friendly characteristics. However, there has been a point of view on the cost compared to conventional lighting as a large obstacle to market penetration of LED. Therefore, companies are developing a Chip-Scale Packaging (CSP) LED technology to improve performance and reduce manufacturing costs. In this study, we perform patent analysis associated with Flip-Chip CSP LED and flow chart for promising technology forecasting. Based on our analysis, we select key patents and key patent players to derive the business strategy for the business success of Flip-Chip CSP PKG LED products.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.9-14
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• 2004

우리나라의 도시 옥외조명은 1988년 서울올림픽을 전후하여 관심이 확대되었으며, 서울시는 1996년 서울시 경관조명기본방향을 설정하고 숭례문 등 각종 문화재에 옥외조명시설을 설치하기 시작하였다. 최근 옥외조명에 대한 필요성을 인식하고, 설치하고 있는 초기단계에 있어 옥외조명을 계획하는데 반드시 고려해야하는 광공해에 대해서는 아무런 인식 없이 과다한 조명으로 광공해를 유발시키고 있다. 미국과 유럽, 일본 등 선진외국에서는 일찍부터 광공해의 심각성을 인식하고, 이를 방지하기 위해 옥외조명조례의 제정과 가이드라인의 발표로 양호한 조명환경 조성을 위해 노력하고 있다. 이에 본 연구는 광공해가 거주자와 보행자에게 미치는 영향을 고려하여 주거지역의 옥외가로조명의 광공해에 관한 연구를 진행하였다. 외국의 경우 광공해가 발생하는 지역의 조명환경개선사업을 펼쳐 광공해에 따른 악영향을 줄임과 동시에 조명에너지 절약의 효과도 가져왔다. 국내의 경우 전반 확산형(Non-Cutoff) 가로등이 보행자에게는 눈부심을 일으키고, 거주자에게는 프라이버시 침해와 숙면에 방해를 가져오므로 차폐된 조명기구를 사용해 이런 영향을 최소화할 필요가 있다. 따라서 국내의 경우 아직 광공해에 대한 기준이나 가이드라인이 없으므로 이에 대한 대책과 기준안 마련이 시급하다.