Effect of N₂O-mediated calcination on nickel species and the catalytic activity of nickel catalysts supported on γ-Al₂O₃ in the steam reforming of glycerol

Choi, Y.,Kim, N.D.,Baek, J.,Kim, W.,Lee, H.J.,Yi, J. Pergamon Press ; Elsevier Science Ltd 2011 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.36 No.6

The steam reforming of glycerol over supported nickel catalysts is a promising and cost-effective method for producing hydrogen. The activity of nickel catalysts supported on γ-Al<SUB>2</SUB>O<SUB>3</SUB> is low, primarily due to the formation of inactive nickel species during high temperature calcination in air. In order to address this problem, a Ni/γ-Al<SUB>2</SUB>O<SUB>3</SUB> catalyst was prepared by calcination at 700 <SUP>o</SUP>C in a nitrous oxide (N<SUB>2</SUB>O) environment. The N<SUB>2</SUB>O calcined catalyst showed an enhanced activity for the steam reforming of glycerol. A variety of characterization techniques (XRD, TPR, XPS and H<SUB>2</SUB> Chemisorption) confirmed that the high temperature N<SUB>2</SUB>O calcination resulted in a significant decrease in the levels of nickel aluminate. The N<SUB>2</SUB>O calcination also led to an enhancement in the amount of NiO as well as nickel ions present on the surface of the catalyst. Interestingly, compared to an air calcined catalyst, the N<SUB>2</SUB>O calcined catalyst contained larger nickel particles after reduction but the N<SUB>2</SUB>O calcined catalyst had a much larger nickel surface area and dispersion, which resulted in higher glycerol conversion and hydrogen yield.

자유드로잉 제품과 패드를 설치한 드로잉 제품의 특성

고관영,명노훈,하종성,이창수,최창권,최병용,허기영,김광수,김동수,장종훈,장윤철,김세환,오정민,하민정,박향자 울산과학대학 2000 연구논문집 Vol.27 No.1

본 연구는 자체 제작한 전체 패드가 부착된 드로잉 금형을 이용하여 SUS, 연강, AI, 6:4황동 판재를 드로잉 가공하여 생산된 제품의 특성을 자유드로잉 하여 얻은 제품의 특성과 비교 분석하였다. SUS 판재의 경우 제품에 발생하는 현상은 벽 주름, 구변주름, 수직 파단, 드로잉상처, 이어링이 발생하였으며 길이변화는 펀치어깨부분에서 가장 많이 늘어남을 볼 수 있었고 벽 주름 부분에 있어서 접혀진 부분은 상대적으로 적게 늘어남을 볼 수 있었다. 연강 판재는 SUS 판재에서 보여준 현상을 나타내었으나 SUS 판재에 비해 수직 파단은 적게 일어난 반면 이어링이 더 크게 일어났다. AI 판재의 경우 수직 파단은 일어나지 않았으나 플랜지 주름과 밑면터짐이 발생하였다. 6:4황동의 경우는 전체패드의 AI 판재 드로잉에서와 같이 밑면터짐과 플랜지 주름의 발생이 일어났다.

Inactivation of bacteria and murine norovirus in untreated groundwater using a pilot-scale continuous-flow intense pulsed light (IPL) system

Yi, J.Y.,Lee, N.H.,Chung, M.S. Academic Press, etc 2016 FOOD SCIENCE AND TECHNOLOGY -ZURICH- Vol.66 No.-

<P>The objective of this study was to characterize the inactivation effects of a pilot-scale continuous-flow intense pulsed light (IPL) system on microorganisms in untreated groundwater used in the food industry. The inactivation effects of laboratory- and pilot-scale IPL systems on murine norovirus (MNV), a human norovirus surrogate, were also investigated. Flow rates of 40, 32, 20 and 12 l/min were tested (corresponding to 89,113, 179, and 290 s of treatment time in a chamber, respectively). A 290-s pilot-scale IPL treatment at an energy dose of 14.02 J/cm(2) resulted in a 4.79-log reduction of Escherichia coli C600 in water with an initial count of 10(5)-10(6) CFU/ml, while a 270-s treatment at an energy dose of 13.05 J/cm(2) resulted in a 2.91-log inactivation of aerobic and facultative anaerobic heterotrophs in untreated groundwater with the initial count of 4.5 x 10(4) CFU/ml. An 89-s treatment at a dose of 4.30 J/cm(2) resulted in a 3.35-log inactivation of MNV in water with the initial count of 10(3)-10(4) PFU/ml. The energy dose and the inactivation level showed linearity for this system. These trends should form the basis of a large-scale IPL-based water management system with improved energy efficiency. (C) 2015 Elsevier Ltd. All rights reserved.</P>

Pharmacokinetics of methotrexate after intravenous and intramuscular injection of methotrexate-bearing negatively charged liposomes to rats

Jeong, Yi N.,Lee, Sun H.,Lee, Myung G.,Hwang, Sung J.,Kim, Chong-K. 충남대학교 약학대학 의약품개발연구소 1995 藥學論文集 Vol.11 No.-

The pharmacokinetics and tissue distribution of methotrexate (MTX) were investigated after intravenous (i.v.) and intramuscular (i.m.) injection of free MTX (treatment Ⅰ), freshly prepared MTX-bearing negatively charged liposomes (large unilamellar vesicles), NLUV (treatment Ⅱ), and empty NLUV mixed manually with free MTX (treatment Ⅲ), 4 ㎎/㎏^-1 as free MTX to rats using an HPLC assay. After i.v. infusion over 1 min, the plasma concentrations of MTX (C_p), area under the plasma concentration-time curve (AUC, 173 vs 402 ㎍ ㎖ min^-1), terminal half-life (t_1/2, 240 vs not determined), mean residence time (MRT, 13.0 vs 83.5 min) and volume of distribution at steady state (V_ss, 289 vs 942 ㎖/㎏^-1) increased significantly, however, total body clearance (CL, 23.1 vs 9.94 ㎖ min^-1 ㎏^-1), renal clearance (CL_R, 8.38 vs 3.39 ㎖ min^-1 ㎏^-1), nonrenal clearance (CL_NR, 14.6 vs 6.53 ㎖ min^-1 ㎏^-1) and the amount of MTX excreted in urine (Xu, 415 vs 333 ㎍) decreased significantly from treatment Ⅱ when compared with the values from treatment Ⅰ. This could be due to the fact that some of the MTX-bearing NLUV are entrapped in the tissues, the rest being present in plasma (increase in MRT and V_ss from treatment c), and slow release of MTX from MTX-bearing NLUV(increase in t_(1/2) from treatmentⅡ). In the present HPLC assay, the concentrations of MTX represent the sum of the free MTX and MTX in MTX-bearing NLUV (increase in C_p and AUC, and decrease in CL from treatment Ⅱ). Saturable formation of 7-OH-MTX from MTX was observed in rabbit blood, nonlinear disposition of MTX also being found in rabbits (decrease in Xu and CL_R from treatment Ⅱ). After i.v. infusion over 1 min, some phamacokinetic parameters of MTX, such as t_1/2 (24.0 vs 56.9 min), AUC (173 vs 234 ㎍ min ㎖^-1), MRT(13.0 vs 29.8 min), CL(23.1 vs 17.1 ㎖ min^-1 ㎏^-1), CL_R(8.38 vs 5.66 ㎖ min^-1 ㎏^-1), CL_NR(14.6 vs 11.4 ㎖ min^-1 ㎏^-1) and Xu (415 vs 290 ㎍) were significantly different between treatments Ⅰ and Ⅲ, however, the differences appeared to be smaller than those between treatments Ⅰ and Ⅱ. After both i.v. and i.m. administration, the amount of MTX remaining per g tissue, or the tissue-to-plasma ratio (T/P) of MTX at 30 min after injection was significantly reduced in the kidney, small intestine, large intestine and stomach from treatment Ⅱ when compared with that from treatment Ⅰ. This implies that the side effects of MTX on the kidney and GI tract could be reduced after i.v. or i.m. administration of MTX-bearing NLUV when compared with those of free MTX. The encapsulation efficiency of MTX in MTX-bearing NLUV was 4.16% and the MTX was released slowly from MTX-bearing NLUV when incubated in phosphatebuffered saline, rat plasma and rat liver homogenate.

Improved Hydrogen Capping Effect in n-Type Crystalline Silicon Solar Cells by SiN(Si-Rich)/SiN(N-Rich) Stacked Passivation

Choi, J.,Balaji, N.,Dao, V. A.,Park, C.,Lee, S.,Kim, J.,Ju, M.,Lee, H.,Lee, Y. J.,Yi, J. Springer Science + Business Media 2014 Journal of electronic materials Vol.43 No.9

남녀 대학생의 신체만족도, 자아존중감과 우울에 대한 비교연구

김나영,김민정,김진경,박민주,박민지,이다솜,이민경,이지영,전양지,정하은 이화여자대학교 간호과학대학 2010 이화간호학회지 Vol.- No.44

The purpose of this study was to know relationship among body image and self esteem, depression obtained from male and female. Also we wanted to know what is differences between male and female groups. We intended to provide basis materials for developing programs to increase body image, self esteem and to decrease depression at the same time. Object of our study were male and female who are in collage. There were 90 people in each group. We used frequency analysis to know general characteristics, and we use frequency analysis and descriptive statistic analysis to know question distribution. We studied relationship among body image and self esteem and depression with using Spearman Correlation and analysised the differences between male and female groups with using T-test. This is the result of our research. 1. ale show higher BCS and BET scores than women. Between male and female, self-esteem have no big differences. And female is more depressive than male. 2. he two elements that body image and depression are in inverse proportion to each other in both male and female university students. 3. The two elements that self-esteem and depression are in inverse proportion to each other in both male and female university students. 4. The two elements that body image and self-esteem are in inverse proportion to each other in both male and female university students. And male have high correlation between BCS and BET, BCS and self-esteem, self-esteem and depression tha female. On the other hand, female have high correlation between BET and self-esteem, BET and depression In short, both male and female have correlation between body image, self-esteem and depression. Especially, between self-esteem snd depression have high correlation. In body image, especially female have high correlation between BET and depression. Finally we found the fact that female is more sensitively react than male about appearance.

Optimized surface passivation of n and p type silicon wafers using hydrogenated SiN_x layers

Dao, V.A.,Heo, J.,Kim, Y.,Kim, K.,Lakshminarayan, N.,Yi, J. North-Holland 2010 Journal of non-crystalline solids Vol.356 No.50

We have investigated surface passivation of n and p type silicon wafers, obtained by controlling silicon-hydrogen bonding and fixed charge densities with the use of hydrogenated SiN<SUB>x</SUB> films. The hydrogenated SiN<SUB>x</SUB> films were deposited by single PECVD at 13.56MHz with SiH<SUB>4</SUB>/NH<SUB>3</SUB> gas mixture. The hydrogenated SiN<SUB>x</SUB> films of refractive indices 2.55-1.92 and high optical band-gap (>3.1eV) were obtained by varying the hydrogenated SiN<SUB>x</SUB> film composition. The fixed charge densities, hydrogen-bonding and carrier lifetime performance in n and p type silicon wafer were analyzed. The highest fixed positive charge of 2.66x10<SUP>12</SUP> (cm<SUP>-2</SUP>) was for the hydrogenated SiN<SUB>x</SUB> film composition of 1.21. Fourier transform infrared spectroscopy measurement was carried out to evaluate the bonding concentration of Si-H and N-H. The minority carrier lifetimes of the hydrogenated SiN<SUB>x</SUB> passivated silicon wafers were up to 153μs and 84μs for p and n type, respectively. Mechanism of surface passivation depends on the type of silicon wafer. The higher Si-H bond density is the key point of n type passivation quality. The large fixed positive charge is used to measure p type passivation quality.

Investigation of lauric acid dopant as a novel carbon source in MgB₂ wire

Lee, C.M.,Lee, S.M.,Park, G.C.,Joo, J.,Lim, J.H.,Kang, W.N.,Yi, J.H.,Jun, B.H.,Kim, C.J. North-Holland 2010 Physica. C, Superconductivity Vol.470 No.20

We fabricated lauric acid (LA) doped MgB<SUB>2</SUB> wires and investigated the effects of the LA doping. For the fabrication of the LA-doped MgB<SUB>2</SUB> wires, B powder was mixed with LA at 0-5wt.% of the total amount of MgB<SUB>2</SUB> using an organic solvent, dried, and then the LA-treated B and Mg powders were mixed stoichiometrically. The powder mixture was loaded into an Fe tube and the assemblage was drawn and sintered at 900<SUP>o</SUP>C for 3h under an argon atmosphere. We observed that the LA doping induced the substitution of C for the B sites in MgB<SUB>2</SUB> and that the actual content of C increased monotonically with increasing LA doping level. The LA-doped MgB<SUB>2</SUB> wires exhibited a lower critical temperature (T<SUB>c</SUB>), but better critical current density (J<SUB>c</SUB>) behavior in a high magnetic field: the 5wt.% LA-doped sample had a J<SUB>c</SUB> value of 5.32x10<SUP>3</SUP>A/cm<SUP>2</SUP>, which was 2.17 times higher than that of the pristine sample (2.45x10<SUP>3</SUP>A/cm<SUP>2</SUP>) at 5K and 6T, suggesting that LA is an effective C dopant in MgB<SUB>2</SUB> for enhancing the high-field J<SUB>c</SUB> performance.

선택성장 내부채널 반도체 레이저 다이오드

안형수,양민,이삼녕,정종제 한국해양대학교 산업기술연구소 2002 연구논문집 Vol.19 No.-

The low threshold current and high power selectively inner-channeled laser (SIC LD) was fabricated and estimated by the selective growth using the low-pressure MOCVD (metal organic chemical vapor deposition) method. The minimum threshold currents in the CW (continuous waves) moes of 8.1mA (cavity=250μm) and 12.9mA (cavity=750μm) were achieved with a stabilized fundamental mode. We could obtain the maximum output powers with the uncoated facets of 100mW at pulsed width and 50mW at continuous waves condition in 250μm cavity length. SIC LD is index-guided laser which has new fabrication techniques different from ridge waveguide structure lasers.

알루미늄 합금의 접착구조물에 대한 접착강도의 평가방법

정남용,이진호 한국공작기계학회 1999 한국생산제조학회지 Vol.8 No.1

In a view point of earth environmental protection and social requirement, adhesively bonded structures of aluminum alloys have become to be employed for the purpose of decreasing fuel ratio by weight reduction and to improve performance in various engineering fields such as aircrafts, automobiles, rolling stocks and so on. In spite of such wide applications in adhesively bonded structures of aluminum alloys, the quantitative fracture criterion and evaluation method of its bonded strength have not been established yet. The objective of this paper is to establish fracture criterion considering stress singularity at interface edges in adhesively bonded structures of aluminum alloys. Through the analyses of boundary element method and static fracture experiments with three different types of specimens in the adhesively bonded joints of aluminum alloys, its fracture criterion was proposed and discussed about strength evaluation of adhesively bonded structures.