도서분류와 도서기호에 관한 소고

이동윤,Lee, Dong-Yun 한국도서관협회 1965 圖協月報 Vol.6 No.6

전해질 변화에 따른 Viologen 자기조립박막의 전하이동 특성 연구

이동윤,박상현,신훈규,박재철,장정수,권영수,Lee, D.Y.,Park, S.H.,Shin, H.K.,Park, J.C.,Chang, J.S.,Kwon, Y.S. 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.12

The self-assembled monolayers of alkane derivatives with sulfur containing head groups on gold substrates have been widely examined recently, since the binding between S atoms and Au surface is strong. The viologen has been widely investigated their well-behaved electrochemistry including electron transfer mediation, the surface-enhanced of the adsorption and the behavior of supramolecular assemblies at electrode surfaces in theses and various studies. Yiologen monolayers are formed onto QCM by self-assembly method. We studied the relationship of electron transfer from changing the anions in 0.1 M NaCl and NaClO$_4$ electrolyte solution. The EQCM measurements revealed the anions transfer during reduction and oxidation, respectively From the EQCM data, the well-defined shape peaks were nearly equal charges by cyclic voltammetry.

SAW 필터용 ZnO 압전 박막의 전기적 특성

이동윤,윤석진,Lee, Dong-Yoon,Yoon, Seok-Jin 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.10

The structural and electrical property of RF magnetron sputtered ZnO thin film have been studied as a function of RF power, substrate temperature, oxygen/argon gas ratio and film thickness at constant sputtering power, sputtering working pressure and target-substrate distance. To analyze a crystallo-graphic properties of the films, $\theta$/2$\theta$ mode X-ray diffraction, SEM, and AFM analyses. C-axis preferred orientation, resistivity and surface roughness highly depended on oxygen/argon gas ratio. The resistivity of ZnO thin film(6000 ${\AA}$) rapidly increased with increasing oxygen ratio and the resistivity value of $9 {\ast} 10^7 {\Omega}cm$ was obtained at a working pressure of 10 mTorr with the same oxygen/argon gas ratio. The surface roughness was also improved with increasing oxygen ratio and the ZnO films deposited with the same oxygen/argon gas ratio showed the excellent roughness value of 28.7 ${\AA}$. With increase of the substrate temperature, The C-axis preferred orientation of ZnO thin film increases and the resistivity decreases due to deviation from the stoichiometric ZnO due to oxygen deficiency.

알루미나를 첨가한 Hydroxyapatite의 기계적 물성에 미치는 Ca/P 몰비의 영향

이동윤,이승규,박훈,김창은,Lee, D.Y.,Lee, S.K.,Park, H.,Kim, C.E. 한국세라믹학회 1991 한국세라믹학회지 Vol.28 No.5

The effect of Ca/P mole ratio (Ca/P=1.60, 1.67, 1.75) in the initial solution on the mechanical properties of alumina added hydroxyapatite was investigated. Hydroxyapatite was synthesized by precipitation method using Ca(NO3)2$.$4H2O and (NH4)2HPO4 as starting materials and 5 wt% of ${\alpha}$-Al2O3 was added to precipitation solution. The powder was calcined at 800$^{\circ}C$ and sintered at 1,150∼1,400$^{\circ}C$ under water vapor atmosphere. With the increasing of Ca/P mole ration in the initial solution, the amount of tricalcium phosphate formed from the decomposition of hydroxyapatite reduced and the sinterability and mechanical properties were increased. The bending strength and Vickers hardness of the specimen sintered at 1,300$^{\circ}C$ with the Ca/P mole ratio of 1.75 in the initial solution were 230 MPa and 650 kg/$\textrm{mm}^2$, respectively. The improvement of mechanical properties was attributed to not only the effect of Ca/P mole ratio but also the strengthening of sintered body by Al substitution for P ions.

Ar/$O_2$에 따른 ZnO 박막의 C-축 배향성에 관한 연구

이동윤,박용욱,남산,이전국,김현재,윤석진,황금찬,Lee, Dong-Yoon,Park, Yong-Wook,Nam, Sahn,Lee, Jeon-Kook,Kim, Hyun-Jai,Yoon, Seok-Jin,Whang, Keum-Chan 한국전기전자재료학회 2000 전기전자재료학회논문지 Vol.13 No.7

Zinc Oxide(ZnO) thin films on Si(100) substrate were deposited by RF magnetron reactive sputtering. The charcteristics of ZnO thin films on argon/oxygen(Ar/O$_2$)gas ratios RF power and substrate temperature were investigated by XRD, SEM, and AFM analyses. C-axis preferred orientation resistivity and surface roughness highly depended on Ar/O$_2$gas ratios. The resistivity of ZnO thin films rapidly increased with increasing oxygen ratio and the resistivity value of 9$\times$10$^{7}$ $\Omega$cm was obtained at a working pressure of 10 mTorr with Ar/O$_2$=50/50. The surface roughness was also improved with increasing oxygen ratio and the ZnO films deposited with Ar/O$_2$=50/50 showed the excellent roughness value of 28.7$\AA$.

한국 폐경 여성의 골다공증 위험 인자에 관한 연구

이동윤,구승엽,김석현,최영민,문신용,김정구,Lee, Dong-Yun,Gu, Seung-Yeop,Kim, Seok-Hyeon,Choe, Yeong-Min,Mun, Sin-Yong,Kim, Jeong-Gu 한국건강관리협회 2004 한국건강관리협회지 Vol.2 No.2

Objective : To identify the risk factors for postmenopausal osteoporosis in Korea Materials and methods : Bone mineral density (BMD) at the lumbar spine and femoral neck was measured by dual energy X-ray absorptiometry in 808 apparently normal postmenopausal Korean women. Questions about life style, demographic parameters, medical history and social habits etc. were asked on these women; 2ll women with normal bone mineral density, and 597 women with osteopenia or osteoporosis. Results 'Age of >50 years, low body mass index (BMI; <18.5 kg/m2), long duration of menopause(>10 years), and previous history of fracture were associated with increased prevalence of osteopenia or osteoporosis. Women without the outside activity also showed a higher frequency of low bone mass, Risk for osteopenia or osteoporosis was low in women with high BMI (>23 kg/m2) and women with job. The prevalence of low bone mass appeared to be independent of the following parameters: socioeconomic status, familial history, smoking, drinking, exercise, previous use of oral contraceptive, coffee or milk consumption, and degree of sunlight exposure. Conclusion 'Age, BMI, duration of menopause, previous history of fracture and degree of outside activity are the risk factors for postmenopausal osteoporosis in Korea.

단위 역률을 갖는 3상 BUCK 다이오드 정류기에서의 새로운 DC 리플-전압 저감 기법

이동윤,최익,송중호,최주엽,김광배,현동석,Lee, Dong-Yun,Choy, Ick,Song, Joong-Ho,Choi, Ju-Yeop,Kim, Kwang-Bae,Hyun, Dong-Seok 전력전자학회 2000 전력전자학회 논문지 Vol.5 No.2

본 논문에서는 3상 강압형 다이오드 정류기에서 출력전압의 저주파 리플 전압을 감소시키기 위한 새로운 제어기법을 제안한다. 제안한 펄스 주파수 변조 기법은 강압형 다이오드 정류기의 출력전압과 넓은 부하 범위에 대한 주 스위치의 영전류 스위칭을 보장하기 위해 적용된다. 본 논문에서 적용된 펄스 주파수 변조 기법은 일반적으로 입력전류의 낮은 고조파의 단위 역률의 장점을 지니고 있다. 또한 출력전압에서 보여진 저주파 리플전압을 감소시키기 위해 효과적으로 사용되어진다. 제안된 제어기법을 자세하게 설명하며 그 타당성을 검증하기 위해 시뮬레인션 및 실험을 통하여 검증한다. A technique to suppress the low frequency ripple voltage of the DC output ${\gamma}$oltage in three-phase buck d diode rectifiers is presented in this paper. The proposed pulse frequency modulation method is employed to r regulate the output voltage of the buck diode rectifiers and guarantee zero-current switching of the switch over the Vvide load range. The pulse frequency control method used in tIns paper shows generally good p performance such as low THD of the input line current and unity power factor. In addition, the pulse f freιluency method can be effectively used to suppress the low frequency voltage ripple appeared in the dc output voltage. The proposed technique illustrates its validity and effectiveness through the respective s simulations and experiments.

염료감응형 태양전지와 열전발전소자를 결합한 복합 태양전지의 구조 및 특성

이동윤,송재성,이원재,김인성,정순종,Lee, Dong-Yoon,Song, Jae-Sung,Lee, Won-Jae,Kim, In-Sung,Jeong, Soon-Jong 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.4

The tandem solar cell composed of a dye-sensitized solar cell (DSC) and a thermoelectric generator (TEG) was designed. In such new cell, the characteristics of DSC and TEG were investigated. DSC uses the wavelength range of 380∼750 nm and has the maximum efficiency of below 10 %. If the solar light transmitted through DSC can be converted to heat energy, TEG can generate electric energy using this heat energy. By this means, it is possible to utilize most of solar energy in the wavelength range of 350∼3000 nm for electric generation and it can be expected to obtain higher solar energy conversion efficiency exceeding the known limit of maximum efficiency. For this purpose we suggest the tandem solar cell constructed with DSC and TEG. In this structure, DSC has a carbon nanotube film as a counter electrode of DSC in order to collect the solar light and convert it to heat energy. We measured the I-V characteristics of DSC and TEG, assembled to the tandem cell. As a result, it was shown that DSC with carbon nanotube and TEG had the efficiency of 9.1 % and 6.2 %, respectively. From this results, it is expected that the tandem solar cell of the new design has the possibility of enhanced conversion efficiency to exceed above 15 %.

Landsat TM 위성영상 픽셀 기반의 녹지 연계망 평가

이동윤,엄정섭,Lee, Dong-Youn,Um, Jung-Sup 한국공간정보학회 2010 한국공간정보학회지 Vol.18 No.2

현재 녹지 연결성 조사는 대부분 현지조사에 의존하고 있어, 특정시기의 특정지점에서 조사된 결과에 주안점을 두고 있다. 그리하여 조사지점의 대표성에 한계가 있고 많은 시간이 소요되고, 조사 대상물 위치의 부정확, 경제적 비효용 등이 문제점으로 지적되어왔다. 본 연구는 이러한 문제에 대한 대안을 제시하기 위해 Landsat TM (Thematic Mapper) 영상의 픽셀에 의거한 녹지 연계망을 평가하고자 출발하였다. 그리하여 원격탐사 기법이 녹지 연계망을 평가할 수 있는 도구로서의 가능성을 지니고 있는 지를 평가하고자 특정 사례 연구지역에 대해 실증적인 연구가 수행되었다. 조사지점에만 국한된 현지조사 방식과 달리 픽셀 기반의 평가는 광역적인 녹지 연계망의 분포실태를 단시간에 제시하였다. 녹지 연계망 훼손 추세 평가는 다양한 시기의 녹지 변화 실태를 정량적으로 제시하고 있기 때문에 그 결과가 녹지 연계망 보전과정에서 설득력을 지닌 근거자료로 활용될 수 있을 것으로 판단된다. 본 연구가 녹지 연계망 감시에서 객관적인 데이터에 의거한 정책결정이 아닌 직관에 의존하여 왔던 관행을 개선될 수 있는 계기가 되어 향후 녹지 연계망 보전관련 중요한 참고자료가 될 수 있을 것으로 사료된다. At present, monitoring programmes for green network have been mainly based on field sampling, which relies on attributes of an area at one point in time, reflecting an emphasis on the small number of in-situ data. One of the major disadvantages of traditional field monitoring is that it is costly, laborious and time consuming due to the large number of samples required. The aim of this research was to evaluate green network based on pixel of Landsat TM satellite image. An empirical study for a case study site was conducted to demonstrate how a standard remote sensing technology can be used to assist in monitoring the green network based on pixel. The pixel-based analysis made it possible to identify area-wide patterns of green network subject to many different type of artificial structures, which cannot be acquired by traditional field sampling. It was demonstrated that the degradation trends of green network could be used effectively as an indicator to restrict further development of the sites since the quantitative data generated from remote sensing can present area-wide visual evidences by permanent record. It is anticipated that this research output could be used as a valuable reference to support more scientific and objective decision-making in monitoring green network.

금형주조한 Al-10%Si 합금의 응고조직과 기계적 성질에 미치는 금형의 냉각효과에 관한 연구

이동윤,천병욱,최창옥 ( Dong Youn Lee,Byung Wook Cheon,Chang Ock Choi ) 한국주조공학회 1993 한국주조공학회지 Vol.13 No.2

N/A This study has been focused on the influence of the metallic mold cooling effects on the solidification structures and the mechanical properties for Al-10%Si alloy castings by the variation of pouring temperatures, metallic mold temperatures and Cooling part of metallic mold. The dendrite arm spacing of Al-10%Si alloy was decreased with increasing cooling rate. In case of bottom cooling of metallic mold, DAS was appeared to be 20-22㎛ and in the middle cooling, it was increased to 36-40㎛. The DAS decreased proportionally with(cooling rate)^(-3/2) at pouring temperatures 680℃ and (cooling rate)^(-½) at pouring temperature 760℃, but it was proportionally increased to(local solidification time)^(½-⅓) at pouring temperature 680℃ and 760℃. The maximum tensile strength of Al-10%Si alloy casting was obtained in case of bottom cooling of mold at pouring temperature 680℃ and metallic mold temperature 320℃.