• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.8.2-8.2
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• 2009

구리(Cu)-인듐(In)-갈륨(Ga)-셀레늄(Se)의 4 원소 화합물 반도체인 Cu(InGa)$Se_2$ (CIGS) 태양전지 세계 최고 셀효율은 2008년 현재 19.9% 로서 박막형 태양전지 중 가장 높은 효율을 보이고 있다. 이는 다결정(폴리) 실리콘 태양전지의 20.3%와 대등한 수준이다. 이 CIGS 태양전지는 제조단가를 표준 결정형 실리콘 태양전지 대비 50% 대로 획기적으로 낮출 수 있어 가장 경쟁력이 있는 차세대 재료로 꼽히고 있다. 본 연구에서는 CIGS태양전지를 고진공 물리 증작법으로 제작하였으며 표면과 박막의 순도를 외부오염을 방지하기 위하여 후면전극, 광흡수체 및 전면전극을 동일 진공에서 제작할 수 있는 멀티 챔버 클러스터 증착 시스템을 이용하였다. 기판으로 소다라 임유리, 후면전극으로 Mo, 전면전극으로 I-ZnO/Al:ZnO 및 ITO를 이용하였다. 버퍼층으로 CdS를 chemical bath deposition (CBD)를 이용하였다. 소자는 무반사막을 사용하지 않고 Al/Ni전극 그리드를 이용하였다. 이 소자로부터 0.22 $cm^2$에서 16%의 효율을 얻었다. 각 박막층 간 계면의 분석을 전기적인 특성, ellisometry에 의한 광특성, 표면과 결정성에 대한 SEM 및 XRD의 특성을 보고한다. 또한, 대표적 화합물 반도체 박막 태양전지인 CIGS 태양전지의 기술의 현황, 학문적인 과제 및 실용화의 문제점을 발표하기로 한다.

• Hwankyungkyoyuk
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• v.8 no.1
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• pp.66-80
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• 1995

The purpose of this study was to investigate the housewives's recognition and practice on prevention of environmental pollution. The subjects of this study were 250 housewives, school students' mothers, living in Cheong-ju. Major findings were as follows: 1. In washing their faces and brushing their teeth, they saved the water very well, but in taking bath, washing the dished, using the water of the lavatory they did not save the water so well. 2. The kinds of the cleansers differed in taking a bath, washing the hair, and doing the laundry respectively : what they use most was hard soaps in taking bath, liquid cleansers mixed with shampoo and linse in washing the hair, and synthetic powder detergent in laundrying. They used more synthetic detergent than natural soaps, which is known to be a cause of water pollution. Especially, when they cleansed, they did not use a measuring cup. It resulted in the waste of detergent and accelerating of water pollution. Therefore, the environmental education for them was very urgently needed. 3. In handling domestic waste, the separate collection rate of empty bottles and old newspapers was very high, but that of used phone-call cards and used batteries was extremely low. It was truly nessesary to educate and step up publicic activities on the separate collection of phone-call cards and batteries caused environmental pollution. 4. The housewives had much knowledge about environmental pollution, but they did not practice it so well in their home. 5. The housewives made more effort than their children in preventing environmental pollution and saving resources. In conclusion, what is most important for solving environmental problem was for each citizen to make an effort to prevent environmental pollution, and the government's support and producing the atmosphere of the society for this was really needed.

• 한국지구물리탐사학회:학술대회논문집
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• 1999.08a
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• pp.1-20
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• 1999

In Japan, geophysical exploration methods have been widely applied to civil engineering and construction fields for a long time. In particular, seismic refraction has long played a significant role in geotechnical site investigations for tunnels, dams and landslides. However, our growing interest on the social and natural environment makes the methods available and its application fields diversify. Digital technologies such as personal computer have revolutionized our ability to acquire large volumes of data rapidly, and to produce more reliable results for subsurface image. Also, color graphics easily visualizes survey results In a more understandable manner, These days geophysical methods are essential to assessing grouting effects, predicting the front of tunnel cutting face, monitoring the movement, pollution and purification process of groundwater. Now three-dimensional exploration techniques have developed for the site characterization in civil engineering and construction needs.

• 한국지구물리탐사학회:학술대회논문집
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• 2002.09a
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• pp.126-138
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• 2002

Designing the bridge with wider span is the present-day trends. Therefore, constructing the foundation on the suitable ground is one of the important factor for the safety of bridge. But, getting a subsurface information under the river is not easy problem. This paper shows results of electrical resistivity survey at the river. Electrical resistivity survey have revealed geoelectrical structure successfully. The result is well matched with boring and can provide useful information on the geological structure such as fault fracture zone for suitable location of foundation. It is expected that application of electrical resistivity survey at the river will be helpful in preventing modification of design due to unexpected ground condition during the construction, or water contamination and increment of costs accompanied with ground reinforcement.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.245-251
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• 1988

Thermolysin was immobilized on Dowex MWA-1 with 10% glutaraldehyde and incorpo rated into a fluidized-bed continuous coagulation scheme to make Cheddar type cheese. The activity yield of thermolysin was 25%. The immobillized thermolysin was stable at $60^{\circ}C$ in the presence of 1/200M calcium ions and the half-life value is 16 days at the temperature. Raw milk alkalified to pH 7.0 was passed through a column of thermolysin beads at $55^{\circ}C$, cultivated with Streptococcus cremoris and allowed to coagulate. A typical milk curd was formed to make Cheddar type cheese, avoiding troublesome microbial contamination successfully during continuous hydrolysis process. During ripening of this cheese for 6 months at $10^{\circ}C$, its ripening ratio and taste were similar to those of cheese prepared by the traditional method.

• Journal of the Korean Society for Railway
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• v.11 no.4
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• pp.364-370
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• 2008

In this paper, we proposed new sensor network architecture with autonomous robots based on beacon mode and implemented real time monitoring system in real test-bed environment. The proposed scheme offers beacon based real-time scheduling for reliable association process with parent nodes and dynamically assigns network address by using NAA (Next Address Assignment) mechanism. For the large scale multi-sensor processing, our real-time monitoring system accomplished the intelligent database processing, which can generate not only the alert messages to the civilians but also process various sensing data such as fire, air, temperature and etc. Moreover, we also developed mobile robot which can support network mobility. Though the performance evaluation by using real test-bed system, we illustrate that our proposed system demonstrates promising performance for emergence monitoring systems.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.983-986
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• 2007

Concrete surface grinding is required for flatness and adhesiveness of concrete surface. The procedure is, however, labor intensive and has a hazardous work condition. Also, the productivity and the quality of concrete surface grinding depend on the levels of worker. Thus, the development of remote controlled concrete surface grinding equipment is necessary to prevent the environmental pollution and to protect the workers from hazardous work condition. However, it is difficult to evaluate the grinded surface objectively in a remote controlled system. The machine vision system developed in this study takes the images of grinded surface with the network camera for image processing. Then, by representing the quality test results to the graphic MMI program of the remote control station, the quality control system is constructed. The machine vision algorithm means the image processing algorithm of grinded concrete surface and this paper presents the objective quality control standard of grinded concrete surface through the application of the suggested algorithm.

• Journal of Navigation and Port Research
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• v.33 no.3
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• pp.221-226
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• 2009

Guidelines on ship recycling are adopted internationally. UNEP adopted 'Basel Convention', providing Environmentally Sound Management(ESM) of facilities and recommendations. IMO adopted 'Guidelines on Ship Recycling', providing measures for worker's safety, how to control pollutant materials and the meaning of 'Green Passport'. IMO Convention (draft) is in progress. ILO adopted 'ILO Guideline', providing how to make sure safety and health for workers in shipbreaking. But Republic of Korea goes against the stream and there is much to be desired. At this point of time, we carried out a study on international trend regarding ship recycling, a plan to cope with international trend, and it is considered to be necessary to establish a special law on ship recycling.

• Resources Recycling
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• v.4 no.3
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• pp.10-18
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• 1995

Recycling of GaAs scrap which occurs durmg the manufachre of GaAs waters is. therefore, required to solve the environmentalproblcrns caused by arsenic metal and to reutilize gallium which is a expensive metal. A thema-analyticalstudy (thermogravimeg. and derivative thermogravimetry) tor the evaporation behavior of Fa, As from Gak\ulcorner scrap powdersat vacuum atmosphere(2-2.5X 10'mmHg); was primarily performed to identi j the possibility of Ga extraction. Until79YC, the weight change of G d s porvder does not take place, at 800-970C range GaAs vaporizes as the GaAs compound,and over 1WO"C it decamposes mto Ga and As md then As vaporizes rapidly as a result of the difference af vaporprcssure for Ga and As, liquid Ga rcmains eventually.mains eventually.

• Applied Biological Chemistry
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• v.31 no.2
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• pp.143-146
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• 1988

The effect of gamma irradiation on controlling infestation of insects on rice grain were investigated. The egg and larva stages of rice weevil (Sitophilus oryzae) were more radiosensitive than the pupal and adult stages. The complete mortal dose of the first two stages was 0.05kGy, while it was 0.5kGy in the second two stages. In indian-meal moth (plodia interpuctella Hubner), sterile doses of egg, larva, pupa and adult were 0.04 to 0.05, 0.05 to 0.06 and 0.2 to 0.25kGy, respectively. Therefore, the irradiation dose within 1.0kGy was considered to be effective for rice storage so far as reinfestation was prevented. Attractiveness of indian-meal moth toward the rice irradiated at 1.0 to 5.0kGy was non-significant in F-test.