GES(gold eletroforming system)를 이용한 임프란트 보철물의 제작에 관한 연구

이성욱,서규원 고려대학교 임프란트연구소 2001 임프란트연구지 Vol.3 No.1

Distortions of casting body and unfitness of margin lead to failure or remaking the implant restorations in the cases of long span bridges. It is necessary to use of eletro forming system and spark erosion machine in the fabrication of the implant restorations to make accurate margin and passive fitness. This study presents new lab. procedure of implant restoration and suggests the joining procedure between electroformed crown and connecting elements with gold bonder.

PEG 분해균주의 분리와 PEG film의 상용성에 관한 연구

이제혁,정성제,이준열,전억한 경희대학교 부설 식량자원개발연구소 1993 硏究論文集 Vol.14 No.-

PEG를 sole carbon과 energy source로서 이용하는 미생물을 자연계에서 분리하였고, PEG의 분자량이 높아질수록 그 분해 미생물의 수가 감소하는 것을 확인하였다. 또한, liquid culture로서 PEG농도를 감소시키는 미생물을 선별하였고, 분해율은 PEG 8000이 약 18.8%였으며 PEG 10000은 약 25.4%인 것으로 조사되었다. PEG film의 제조를 위해 EMAA 및 EAA와의 상용성을 적외선 분광(IR) 스펙트럼을 사용하여 조사한 결과, EMAA와 EAA의 카르보닐기와 PEG의 에테르기와의 강한 수소결합이 형성으로 blend film제조시 상용성이 있는 것으로 확인되었다. Several strains capable of degrading PEGs(Polyethylene Glycols)were isolated and investigated for their biodgradation ability of PEGs. Microorganisms screened for the biodegradation studies were those grown on the PEG used as a sole carbon and energy source. It was known that the number of microorganisms decreased when grown on the high molecular weight of PEG(e.g. 20,000). A liquid culture was carried out with such microorgaisms and resulted in the decrease in PEG concentration meaning that PEG was degraded in the reactor. The biodegradability was found to be about 18.8% for PEG-8000 and 25.4% for PEG-10000, respectively. For the manufacture of biodegradable PEG film, EMAA/PEG and EAA/PEG blending ability was investigated with IR spectrum and showed that it was possible to produce blending film.

Tufftride處理 後 高周波 硬化處理된 軟鋼의 機械的 性質및 高周波 硬化 特性에 관한 硏究

田炳旭,李相允 東亞大學校 大學院 1984 大學院論文集 Vol.8 No.2

A combined heat treatment of tufftride and induction-hardening treatment for mild steel specimens has been carried out to investigate into the improvement in mechanical properties and some induction-hardening characteristics. The results obtained from this experiment are given below; 1. Optical micrographs have shown to vary as changes in the rate of travel at a given output power during induction-hardening, resulting in the decomposition of compound layer and the formation of the Fe-C-N martensitic structure when the travel rate of 3.1 mm/sec. is maintained. 2. Hardness measurements have revealed that specimens treated at the travel rate of 6.2 mm/sec. show an increase in hardness compared to specimens tufftride-treated due to the fact that the content of solute atom dissolved in ferrite increases during induction-hardening, whereas for travel rates of 4.4 mm/sec. and 3.1 mm/sec. the formation of martensitic structure gives a considerable increase in hardness. 3. It has been found that for a given output power as the rate of travel decreases hardness increases, and that the travel rate of 3.1 mm/sec. shows a great increase in surface hardness and effective hardening depth as compared to the travel rate of 4.4 mm/sec. 4. Specimens tufftrided, induction-hardened, and then tempered have shown a somewhat decrease in hardness and an increase in toughness compared to that obtained before tempering treatment. 5. Tensile test has shown that the tensile strength of mild steel specimens treated by this combined heat treatment increases as tufftride treating time increases and as the rate of travel decreases. 6. It has been shown that for a given rate of travel under the same panel control during induction-hardening the output power increases with increasing the diameter of specimens, and smaller specimens generally shows a higher hardness value.

農家副業으로서의 畜産現況과 그 改善方案에 關한 硏究

洪鐘旭,李熙碩,朴恒均,崔源弼,李鉉凡,金祥基 慶北大學校 1978 論文集 Vol.25-26 No.-

Recently, there have been much corncerns about the strategies which can reasonably increase farm income at the average farm level. In other words, as a result of third-term Five Year Economic Development Plan there was a remarkable gap between farm household and non-farm household incomes. Therefore, various policy tasks to eliminate this unbalanced income growth are currently being implemented. This study was carried out to identify the situation of livestock farming at general farm level, regarded as one of income generation strategies for the farm sector. Some results of the study can be summarized as follows: First of all, it was found that a group of farms which raise a small size of animals like Korean cattle, hog, and various poultry gave higher resource bases as compared with that of non-livestock farms. Secondly, it was also recognized that both farm and farm household income levels of small-scale livestock farms were higher than those of non-livestock farm group within the same region, specifically as much as approximately ￦200,000. Thirdly, it was known that the average size of animal raising per household in 0.9 head of cattle, 0.8 head of hog, and 34 lyers of poultry, respectively. To the end, according to the farm disposal practices of major by-products, only about 18 percent of total rice straws produced at individual farms was utilized for the animal raising, and about 45 percent of all the brans available at farms for the livestock enterprise. The rest of straw and brans in regarded as selling at farm level. In this respect, it may be recommended either to increase current size of animals or to expand number of livestock farms.

일개 대학병원에서 일년간 분리된 반코마이신 내성 장구균의 임상 분자역학적 연구

송진영,김창억,김성욱,우흥정,김미란,이규만,이란,장미화,정희진,김우주 대한화학요법학회 2001 대한화학요법학회지 Vol.19 No.4

목적 : 한강성심병원에서는 2000년 3월 반코마이신내성 장구균이 처음 분리되어, 원내전파를 막기 위한 노력을 하였으나, 분리가 지속되었다. 따라서 이에 대한 좀더 자세하고 객관적인 자료를 얻기 위해 본원에서 분리된 반코마이신내성 장구균에 대한 임상분자 역학적 연구를 시행하게 되었다. 방법 : 2000년 3월부터 2001년 2월까지 한림대학교 한강성심병원에서 분리된 장구균을 대상으로 디스크 확산법, 최소발육억제 농도등의 측정을 통해 반코마이신 내성여부를 확인하였으며, 반코마이신내성 장구균을 대상으로 PFGE를 시행하여 형별 분석을 하였다. 결과 : 분리된 균주는 총 32균주로 모두 E. faecium이었다. 항생제 내성 검사 결과 모두 Van A형이었다. PFGE 결과 1a형이 8검체, 1b형이 5검체, 2a형이 4검체, 2b형이 4검체, 3a형이 2검체, 3b형이 5검체였고, 그 외 4, 5, 6형이 각각 1검체씩이었다. 총 32균주 중 56%(18/32)의 균주가 같은 시기, 같은 병실에서 동일한 PFGE 형을 보이면서 분리되었다. 결론 : 반코마이신내성 장구균의 PFGE 분석 결과 여러 종류의 반코마이신내성 장구균이 유행하였음을 알 수 있다. 그러나 같은 기간, 같은 병실에서 분리된 균주의 PFGE 형이 같은 것이 상당수 있었다. 이는 반코마이신내성 장구균의 원내 전파가 있었음을 의미한다. 따라서 반코마이신내성 장구균의 전파의 발생 및 전파 방지를 위해서는 보다 효과적인 감염관리 활동이 필요할 것으로 생각된다. Background: Vancomycin-resistant enterococci(VRE) have been a rising problem worldwide. In March 2000, VRE was first isolated from a patient in Hangang Sacred Heart hospital. Although efforts to prevent transmission of VRE were performed, isolations continued. So molecular epidemiological study of VRE was done. Method : The minimal inhibitory concentration(MIC) to vancomycin and teicoplanin, and pulsed field gel electrophoresis(PFGE) pattern of VRE isolated from March 2000 to February 2001 were evaluated. Results : 32 VRE were isolated. All of the VRE were Enterococcus faecium and showed Van A resistance phenotype. We found out that a significant number of VRE isolated during same period and in same room, were same PFGE patterns. (18 cases/ 32 isolates= 56%) Conclusion: This study demonstrated the spread of VRE of same PFGE patterns. It suggests the nosocomial spreads of VRE.

Iridium Cyclometalates with Tethered <i>o</i>-Carboranes: Impact of Restricted Rotation of <i>o</i>-Carborane on Phosphorescence Efficiency

Lee, Young Hoon,Park, Jihyun,Lee, Junseong,Lee, Sang Uck,Lee, Min Hyung American Chemical Society 2015 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.137 No.25

<P>Iridium(III) cyclometalates (<B>1c</B> and <B>2c</B>) in which the two carborane units on the 4- or 5-positions of 2-phenylpyridine (ppy) ligands were tethered by an alkylene linker were prepared to investigate the effect of free rotation of <I>o</I>-carborane on phosphorescence efficiency. In comparison with the unlinked complex, tethering the <I>o</I>-carboranes to the 5-positions of ppy ligands (<B>2c</B>) enhanced phosphorescence efficiency by over 30-fold in polar medium (Φ<SUB>PL</SUB> = 0.37 vs 0.011 in THF), while restricting the rotation of <I>o</I>-carborane at the 4-positions (<B>1c</B>) negatively affected the phosphorescence efficiency. The different effects of restricted rotation of <I>o</I>-carborane on phosphorescence efficiency were likely a result of the different variations of the carboranyl C–C bond distances in the excited state.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2015/jacsat.2015.137.issue-25/jacs.5b04576/production/images/medium/ja-2015-04576w_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja5b04576'>ACS Electronic Supporting Info</A></P>

AN EXPERIMENTAL STUDY OF BIOMASS GASIFICATION IN A MICROWAVE PLASMA BURNER

Sang Ju LEE,Yong Cheol HONG,Chang Hyun JO,Yong Uck SHIN,Manoj Yadav,Chang Woo OHK,Bong Ju LEE 한국신재생에너지학회 2013 AFORE Vol.2013 No.-

Thermodynamic Control of Diameter-Modulated Aluminosilicate Nanotubes

Lee, Hoik,Jeon, Yangjun,Lee, Youngil,Lee, Sang Uck,Takahara, Atsushi,Sohn, Daewon American Chemical Society 2014 The Journal of Physical Chemistry Part C Vol.118 No.15

<P>The diameter of imogolite nanotubes was regulated by altering the synthesis temperature and was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and <SUP>29</SUP>Si cross-polarization magic angle spinning nuclear magnetic resonance (CP-MAS NMR). Imogolite diameter modulation via thermodynamic control was induced by curvature formation of the proto-imogolite cluster, which was dependent on the degree of silanol (SiOH) substitution. At lower temperature, 323 K, the amount of SiOH substitution in the proto-imogolite clusters decreases and accordingly reduces the hydrogen bonding among SiOH substituents. In contrast, at higher temperature, 371 K, the large amount of SiOH substitution in the proto-imogolite clusters increases the hydrogen bonding among silanol groups, which also increases the degree of the curvature. The proto-imogolite clusters with a larger curvature can quickly create tubular structures by forming a circle with a smaller diameter.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-15/jp411725z/production/images/medium/jp-2013-11725z_0007.gif'></P>

Influence of Exchange-Correlation Functional in the Calculations of Vertical Excitation Energies of Halogenated Copper Phthalocyanines using Time-Dependent Density Functional Theory (TD-DFT)

Lee, Sang Uck Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.8

The accurate prediction of vertical excitation energies is very important for the development of new materials in the dye and pigment industry. A time-dependent density functional theory (TD-DFT) approach coupled with 22 different exchange-correlation functionals was used for the prediction of vertical excitation energies in the halogenated copper phthalocyanine molecules in order to find the most appropriate functional and to determine the accuracy of the prediction of the absorption wavelength and observed spectral shifts. Among the tested functional, B3LYP functional provides much more accurate vertical excitation energies and UV-vis spectra. Our results clearly provide a benchmark calibration of the TD-DFT method for phthalocyanine based dyes and pigments used in industry.

Three-dimensional evaluation of compositional and structural changes in cycled LiNi_1/3Co_1/3Mn_1/3O₂ by atom probe tomography

Lee, Ji Yeong,Kim, Ji Yoon,Cho, Hae In,Lee, Chi Ho,Kim, Han Sung,Lee, Sang Uck,Prosa, Ty J.,Larson, David J.,Yu, Tae Hwan,Ahn, Jae-Pyoung Elsevier 2018 Journal of Power Sources Vol.379 No.-

<P><B>Abstract</B></P> <P>Accelerated capacity fading of LiNi<SUB>1/3</SUB>Co<SUB>1/3</SUB>Mn<SUB>1/3</SUB>O<SUB>2</SUB> (NCM111) electrode by the chemical migration of lithium (Li) or transition metals (TMs), and surface reconstruction in the surface during electrochemical cycling were evaluated by correlative analysis of atom probe tomography (APT) and transmission electron microscopy (TEM). The cycled NCM111 showed a lack of Li at surface which provides the driving force for long-range Ni migration toward surface. A schematic model for phase transformation and the kinetics of TM migration within the layered structure by density functional theory (DFT) calculations was proposed. This study provides insights into capacity loss and voltage fade upon electrochemical charge-discharge process of NCM111 by measuring the variation of Li composition away from the surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Correlative TEM and APT analysis of the chemical migration and phase of cycled NCM. </LI> <LI> APT analysis of three-dimensional surface atomic concentration. </LI> <LI> DFT-based phase transformation model and kinetics of TM migration is proposed. </LI> </UL> </P>