• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.12.1-12.1
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• 2010

We have developed a facile method to position different dyes (N719 and N749) sequentially in a mesoporous TiO2 layer through selective desorption and adsorption processes. Only upper part of the first adsorbed N719 dye was selectively removed by the desorption solution formulated with polypropylene glycol and tetrabutylammonium hydroxide without any damages of the dye. The desorption depth was controlled by the number of desorption process. Multi-dyed dye-sensitized solar cells (MDSSC) were fabricated by utilizing the method and their photovoltaic properties were investigated. From the incident photon-to-current conversion efficiency (IPCE) measurement, it was found that the MDSSC exhibited the extended spectral response for the solar spectrum while without decrease of maximum IPCE value compare to the DSSCs using one kind of dye (N719 or N749). The highest photocurrent density of 19.3 mA/cm2 was obtained from the MDSSC utilizing $15\;{\mu}m$ N719 / $14\;{\mu}m$ N749 bi-layered mesoporous TiO2 film. The photocurrent density was 25% and 8% higher than that of the DSSC using only N719 and N749 dye as a sensitizer, respectively. The power conversion efficiency of 9.8% was achieved from the MDSSC under the AM 1.5G one sun illumination.

• 한국환경복원기술학회지
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• 제12권6호
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• pp.51-62
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• 2009

The purpose of this study is to analyze the profitability by selecting Pinus densiflora S. et Z. worthy of ornamental tree from among the cutting timber in the urban development project, and then presents the improvements. The study site is the whole area of Oedong-eup Gyeongju city Gyeongsangbuk-do and subject trees numbers are 2,180 trees. Analysis method is cost analysis because it is used generously pubic land development. In results, at first, in case of forest development currently cutting tree costs 7.3 million Won/ha. and no profit is occurred at all. Secondly, the forward direction order of tree treatments expenses are in sawdust production, selling lumber, selling ornamental tree, and selling ornamental tree, sawdust production, selling lumbered on the aspect of profits by the selling stumpage. Especially, selling trees as ornamental tree costs 127 million Won/ha. which shows the highest profits. Third, the management of ornamental tree pine tree after transplantation from development site costs 5 times less than purchasing the same quality trees. Hence, it is recommended to re-utilize the trees from the development sites to produce a high standard gardens and it also provides the basis for the low carbon green growth society.

• 한국정밀공학회지
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• 제24권4호
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• pp.93-101
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• 2007

Aluminum alloy which is one of the light materials has been tried to apply to light weight vehicle body. In order to do that, welding technology is very important. In case of the aluminum laser welding, the strength of welded part is reduced due to porosity, underfill, and magnesium loss. To overcome these problems, laser welding of aluminum with filler wire was suggested. In this study, experiment about laser welding of AA5182 aluminum alloy with AA5356 filler wire was performed according to process parameters such as laser power, welding speed and wire feed rate. The tensile strength was measured to find the weldability of laser welding with filler wire. The models to estimate tensile strength were suggested using three regression models and one neural network model. For regression models, one was the multiple linear regression model, another was the second order polynomial regression model, and the other was the multiple nonlinear regression model. Neural network model with 2 hidden layers which had 5 and 3 nodes respectively was investigated to find the most suitable model for the system. Estimation performance was evaluated for each model using the average error rate. Among the three regression models, the second order polynomial regression model had the best estimation performance. For all models, neural network model has the best estimation performance.

• Journal of Chest Surgery
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• 제15권4호
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• pp.402-408
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• 1982

The primary cardiac tumor was considered as a form of disease with poor prognosis in the past and it was hardly diagnosed before post mortem autopsy. But recent development of diagnostic procedure and the cardiac surgery using extracorporeal circulation increased the accuracy of diagnosis and the opportunity of successful treatment. The authors present two cases of left atrial myxoma which experienced during recent 4 years between 1979 and 1982. A 33 year old woman admitted with severe shortness of breath, generalized edema, ascites and the evidence of hepatopathy resulted from right sided heart failure. Preoperatively, the patient was treated with conservative medication to improve general condition for a few days. The tumor mass was removed successfully under the cardiopulmonary bypass. She, however, died of myocardial dysfunction showing low blood pressure. The tumor mass weighed 22gm and measured 5.2x4.5x3.6 cm in size. A 60 year old man admitted with shortness of breath on exertion and an episode of fainting. Following the removal of tumor mass under the cardiovascular bypass, the clinical course was satisfactory with no complication. The tumor mass weighed 105gm and measured 9x4x5 cm in size.

• 한국분말재료학회지
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• 제14권5호
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• pp.298-302
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• 2007

In recent years, a rapid increase in demands for the soft magnetic composite parts has been created and it has been tried to improve their properties by various processing methods, alloying elements and compaction parameters. Warm compaction method has been used for the reduction of residual stress, the improvement of magnetic properties and the higher densities. In this work, the effects of warm compaction and polymer binder on magnetic properties of Fe powder core were investigated. The sintering powder, Fe oxide, was ball-milled for 30n hours. And then ball-milled Fe oxide powder was reduced through hydrogen reduction process. The hydrogen reduced Fe powder and polymer binder were mixed by 3-D turbular mixer. And then the mixed powder was warm-compacted. The magnetic properties such as core loss and permeability were measured by B-H curve analyzer.

• 환경영향평가
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• 제10권3호
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• pp.223-234
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• 2001

In this study, we conducted a survey to examine the runoff characteristics of nonpoint sources, which wash off pollutants from the surface of basin during rainfall and affect water pollution of streams. An Anyangchun basin in the region Ewiwang City was selected as a study site. The basin divided into several subbasins such as Wanggokchun, Ojeonchun, and Anyangchun based on the tributaries, which confluence to the main stream of Anyangchun. Four times of field examination had been carried out between July and August of 2000, and water quality data collected from the surveys had been analysed. The survey includes in-situ flow, DO and PH measurements in the outlet of catchment. Laboratory analysis includes BOD, TN, TP. From the result, pollutant by runoff of nonpoint sources were washed out along with stormwater in the beginning of rainfall, and flowed into streams resulted in stream pollution. In case of BOD, the load from Ojeonchun catchment, most of which included urban areas, took up 50% of the total load from the entire watershed. Thus, by the results, it is clear that runoff load by urban nonpoint sources plays an important role in the control and management of nonpoint sources for the watershed.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 추계학술대회 및 정기총회
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• pp.44-44
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• 2014

Yeasts were isolated from wild flowers of some islands and mountains such as Jeju-do, Ulleungdo, Yokjido, Seonyudo and Gyejoksan, Oseosan, Beakamsan and Deogyusan in Korea and were identified by comparison of nucleotide sequences for PCR-amplified D1/D2 region of 26S rDNA or internal transcribed pacer(ITS) 1 and 2 including 5.8S rDNA using BLAST. Seventy two yeast strains of two hundred eighty nine species were isolated from wild flowers in islands and mountains, Korea. Among them, Cryptococcus species were isolated the most dominantly, and Metschnikowia reukaufii were also isolated thirty species, 10.3% of total strains. Twenty-three species including Cryptococcus aureus were overlapped between yeast strains of the islands and mountains. Some physiological functionality of the culture broth and cell-free extracts from two hundred eighty nine yeast strains were determined. The supernatant of Candida sp. 78-J-2 showed antioxidant activity of 22.5%, and supernatant of Metschnilowia reukaufii SY44-6 showed anti-gout xanthine oxidase inhibitory activity of 49.6% and whitening tyrosinase inhibitory activity of 38.4%, respectively.

• Journal of Microbiology and Biotechnology
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• 제21권3호
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• pp.263-266
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• 2011

Methylelaiophylin isolated from Streptomyces melanosporofaciens was selected as an ${\alpha}$-glucosidase inhibitor with an $IC_{50}$ value of 10 ${\mu}M$. It showed mixed-type inhibition of ${\alpha}$-glucosidase with a $K_i$ value of 5.94 ${\mu}M$. In addition, methylelaiophylin inhibited the intracellular trafficking of hemagglutinin-neuramidase (HN), a glycoprotein of Newcastle disease virus (NDV), in baby hamster kidney (BHK) cells. Methylelaiophylin inhibited the cell surface expression of NDV-HN glycoprotein without significantly affecting HN glycoprotein synthesis in NDV-infected BHK cells.

• Transactions on Electrical and Electronic Materials
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• 제7권6호
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• pp.283-292
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• 2006

So that high-strength and electrical properties apply by excellent high voltage insulator electricity material, ATH content and platinum-based flame retardant that influence in flame retardant and tracking characteristic among composite of silicone rubber studied mechanical strength and influence getting to electrical properties. Composition of ${\alpha}$, ${\omega}-vinyl$ poly (dimethyl-methylphenyl) siloxane(VPMPS) of a polymer quantity made doing mole of D4, $D3^{Me,Ph}$ and VMS by 1000:15:0.2 mole ratio and uses basic catalyst tetramethylammonium silanolate(TMAS) and do opening equilibrium polymerization to be used to main polymer for high voltage insulation insulator. Control ATH content and content of platinum-based flame retardant and made high voltage insulation silicone rubber. Measured mechanical strength of making silicone rubber using UTM, and tracking characteristic according to standard of IEC 60587, flame retardant test studied effect that flame retardant characteristic gets in tracking characteristic, measuring according to UL94V method of test.

• 천문학회보
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• 제37권2호
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• pp.149.2-149.2
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• 2012

세계전파통신회의 (WRC; World Radiocommunication Conference)회의는 국제전기통신연합 (ITU)에서 규정하는 국제 전파법 제개정을 위해, 3-4년 간격으로 개최되는 전파통신 관련 최고회의라고 할 수 있다. WRC-15회의는 2015년 11월 2일 - 11월 27일에 걸쳐 스위스 제네바에서 개최될 예정이며, 과학업무 관련 의제들은 다음과 같다. 즉, 7145-7235 MHz 또는 7-8 GHz 대역의 지구탐사위성(지구대우주)업무의 1순위 분배연구, 지구탐사위성업무용 연속 600MHz 대역 분배방안 연구 (8,700~10,500MHz대역 내), 우주선 근거리통신용 관련 규정 재검토, 윤초삭제와 관련된 세계협정시(UTC) 개정 또는 대처방안 연구가 있다. 그리고 모바일광대역 응용 실현을 위한 이동통신업무 추가 분배 및 IMT 추가 지정 연구, 7150-7250MHz (우주대지구), 8400-8500MHz (지구대우주)에서 고정위성업무 추가 분배연구, 나노 위성 및 피코 위성 규제 관련 연구들이 있다. 따라서 본 발표에서는 WRC-15회의의 과학업무 의제들 가운데, 국내전파망원경 운용에 영향을 미칠 수 있는 주파수 대역 및 윤초 관리 등과 관련된 주요 과학업무 의제를 소개하고 이에 대한 향후 대응책 검토를 하고자 한다.