Scintillation properties of the Gd3Al2Ga3O12 : Ce crystal

김혜림,김홍주,장은정,이원근,기문광,Heun-Duk Kim,전구식,Vladimir Kochurikhin 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.1

We investigated luminescence and scintillation properties of the Gd3Al2Ga3O12 : Ce (GAGG) crystal grown in TPS(Total Polishing Solution) Co.. The GAGG crystal has the highest light yield among oxide crystal at room temperature and fast decay time for the detection of radioactivity and in nuclear and particle physics experiments and medical imaging. The scintillation properties of the GAGG crystal were studied by comparing the GAGG crystals grown by two companies. We measured an X-ray induced emission spectra, an energy resolution, an absolute light yield and a decay time. A pulse shape discrimination capability for a and g-ray was also demonstrated.

충북 제천 남천초등학교 발명공작교실

김혜림,Kim, Hye-Rim 한국발명진흥회 2006 發明特許 Vol.31 No.2

Analysis on Recovery in Au/YBCO thin Film Meander Lines

김혜림,임성우,오성용,현옥배,Kim, H.R.,Yim, S.W.,Oh, S.Y.,Hyun, O.B. The Korean Superconductivity Society 2007 Progress in superconductivity Vol.9 No.1

We investigated recovery in $Au/YBa_2Cu_3O_7$ (YBCO) thin film meander lines on sapphire substrates. The meander lines were fabricated by patterning YBCO films coated with gold layers. The lines were subjected to simulated AC fault current and then small current was applied for recovery measurements. The samples were immersed in liquid nitrogen during the experiment. After the fault, the resistance decreased linearly, first slowly and then fast to zero. The initial slow decrease was due to the decrease of the meander line temperature, whereas the fast decrease was originated from the transition from the normal state to the superconducting state. The recovery speed depended on the size of samples, and was faster in the smaller samples during the whole period of recovery. The experimental results were analyzed quantitatively with the concept of heat transfer within the sample and to the surrounding liquid nitrogen. A heat balance equation was solved for the initial phase of recovery, and an expression for the time dependence of resistance was obtained. The result agreed with data well.

Temperature Behavior of Superconducting Fault Current Limiters during Quenches

김혜림,심정욱,현옥배,Kim H.-R.,Sim J.,Hyun O.-B. The Korean Superconductivity Society 2005 Progress in superconductivity Vol.6 No.2

We investigated temperature behavior of superconducting fault current limiters (SFCLs) during quenches. Knowledge on temperature behavior during quenches is important to the design of SFCLs, because the temperature of SFCLs is related to their stability. SFCLs were fabricated by patterning $Au/YBa_2Cu_3O_7$ thin films grown on sapphire substrates into meander lines by photolithography. A gold film grown on the back side of the substrate was patterned into a meander line, and used as a temperature sensor. The front meander line was subjected to simulated AC fault currents, and the back line to DC current. They were immersed in liquid nitrogen during the experiment for effective cooling. Overall, temperature at the back side of SFCLs was close to that at the front side. It was closer at the beginning of faults, and at lower applied voltages. Temperature distribution at the back side was even except at the edge, as at the front side. These results tell that the whole SFCL was heated to similar degree during quenches, and that effective cooling of SFCLs at the back side is as important to the stability of SFCLs as at the front side. The results could be explained with the concept of heat transfer within the film.

Resistance Development in Au/YBCO Thin Film Meander Lines under High-Power Fault Conditions

김혜림,심정욱,최인지,임성우,현옥배,Kim, H.R.,Sim, J.,Choi, I.J.,Yim, S.W.,Hyun, O.B. The Korean Superconductivity Society 2006 Progress in superconductivity Vol.8 No.1

We investigated resistance development in $Au/YBa_2Cu_3O_7(YBCO)$ thin film meander lines during high-power faults. The meander lines were fabricated by patterning 300 nm thick YBCO films coated with 200 nm thick gold layers into meander lines. A gold film grown on the back side of the substrate was also patterned into a meander line. The front meander line was connected to a high-power fault-test circuit and the back line to a DC power supply. Resistance of both lines was measured during the fault. They were immersed in liquid nitrogen during the experiment. Behavior of the resistance development prior to quench completion could be understood better by comparing resistance of the front meander lines with that of the back. Quench completion point could be determined clearly. Resistance and temperature at the quench completion point were not affected by applied field strength. The experimental results were analyzed quantitatively with the concept of heat transfer within the meander lines/substrate and to the surrounding liquid nitrogen. In analysis, the fault period was divided into three regions: flux-flow region, region prior to quench completion, and region after quench completion. Resistance was calculated for each region, reflecting the observation for quench completion. The calculated resistance in three regions was joined seamlessly and agreed well with data.

3원색 분산염료를 이용한 PET 섬유의 Black 염색

김혜림,장혜경,이정진,Kim, Hae-Rim,Jang, Hae-Kyoung,Lee, Jung-Jin 한국섬유공학회 2008 한국섬유공학회지 Vol.45 No.6

In black dyeing of PET fabric, high concentrations of disperse dyes of three primary color are generally required, which leads low exhaustion level of dyes and discharge of unfixed dye into dyehouse effluent. In this study, the effect of combination ratio of dye concentration, liquor ratio, and dyeing pH on dyeing and color property of black dyed PET fabric was investigated. From the results, high K/S values and low lightness $(L^*)$ of PET fabric could be obtained with relatively small amount (1%owf) of yellow dye on condition that red and blue dye were used in high concentration. The dyeing results of red dye were consistent with those of yellow dye while blue dye did not follow the trend. Use of small amount of blue dye and large amount of yellow and red dyes resulted in PET fabric of grayish red color instead of black. Dyeing and color property of black dyed PET fabric were found to be dependent upon dyeing pH while not on liquor ratio.

나노웹으로 코팅된 네오프렌 직물의 제조 및 특성분석

김혜림,이선희,Kim, Hyelim,Lee, Sunhee 한국섬유공학회 2016 한국섬유공학회지 Vol.53 No.2

The main objective of this study was to develop improved functional textiles for marine leisure clothing. Neoprene fabrics were coated with carbon nanofibers (CNFs)/Poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) composite solution comprising 0-16 wt% CNF in 1-5 wt% PVDF-HFP via electrospinning. Electrospinning was carried out from 15 to 24 kV. Neoprene textiles coated with the CNF/PVDF-HFP composite with various applied voltages were characterized as follows: Morphology was examined using an image analyzer microscope system and a field emission scanning electron microscope (FE-SEM). The thermal storage property of these materials was also analyzed using a thermal imaging camera with a forward looking infrared (FLIR) system. The resultant samples that were laminated with a knitted fabric composed of 80% nylon and 20% polyurethane were subjected to a thermal insulation property test. The test and control specimens were irradiated for 60 min. The test specimen and the control specimen were analyzed by considering the differences in temperature between both specimens on heating. Water penetration resistance of the laminated knitted fabric with the CNF/PVDF-HFP composite nanoweb-coated neoprene fabric was measured. The water repellent property test was conducted using a drop shape analyzer (DE/DSA 100, Kruse). The results indicated that an increase in the density of nanoweb-coated neoprene fabric surface correlated with improved thermal storage, thermal insulation, water penetration resistance, and water repellent properties. In addition, increasing amounts of CNFs in the CNFs/PVDF-HFP composite solution resulted in increased thermal storage, thermal insulation, and water repellent properties.

소다배소(焙燒) 및 수침출법(水浸出法)에 의한 탈질용(脫窒用) 폐(廢) SCR 촉매(觸媒)로부터 바나듐과 텅스텐 침출(浸出)

김혜림,이진영,김준수,Kim, Hye-Rim,Lee, Jin-Young,Kim, Joon-Soo 한국자원리싸이클링학회 2012 資源 리싸이클링 Vol.21 No.6

탈질용 선택적 촉매 환원(SCR) 촉매는 화력발전소의 탈질 시스템에서 발생한다. 폐 SCR 촉매로부터 바나듐 및 텅스텐과 같은 유가금속을 회수하기 위한 공정은 소다배소 및 수침출 법으로 이루어진다. 본 연구에 사용된 폐 SCR 촉매는 $V_2O_5$ 1.23 %, $WO_3$ 7.73 %를 함유하고 있다. 소다배소 공정은 바나듐과 텅스텐 화합물을 수용성의 물질로 전환시켜 주는 역할을 하며, 실험은 $Na_2CO_3$ 첨가량 5 당량, 배소온도 $850^{\circ}C$, 배소시간 120 분, 폐촉매 입자크기 $54{\mu}m$의 조건에서 수행하였다. 소다배소 실험 이후 배소산물을 사용하여 수침출 실험을 수행하였다. 침출실험을 위한 배소산물은 $-45{\mu}m$의 입자크기로 분쇄하였으며, 수침출 실험조건은 침출온도 $40^{\circ}C$, 침출시간 30 분, 광액밀도 10 %이다. 소다배소 및 수침출 실험결과, 바나듐 46 %, 텅스텐 92%의 침출율을 얻었다. Selective catalytic reduction(SCR) catalysts are obtained from de-NOx system of thermoelectric power plant. A process was developed for valuable metals such as vanadium and tungsten recovery from spent SCR catalyst by using soda roasting followed by water leaching. Spent SCR catalyst having $V_2O_5$(1.23 mass %) and $WO_3$(7.73 mass %). For getting soluble metal forms of the targeted metals like vanadium and tungsten soda roasting process was implemented. In soda roasting process, sodium carbonate added 5 equivalent ratio at roasted temperature $850^{\circ}C$ with 120 min roasted time for $544{\mu}m$ particle size of spent SCR catalyst. After soda roasting process moved to water leaching for roasted spent catalyst. Before leaching process the roasted spent catalyst was grinded up to $-45{\mu}m$ size. The leaching time is 30 min at $40^{\circ}C$ temperature, 10 % pulp density. The final leaching efficiency obtained 46 % of vanadium and 92 % of tungsten from present process.

그래핀/WPU 복합체 코팅 면적에 따른 전기 발열 텍스타일의 특성에 관한 연구

김혜림,이선희,Kim, Hyelim,Lee, Sunhee 한국섬유공학회 2017 한국섬유공학회지 Vol.54 No.5

In this study, a graphene/waterborne polyurethane (WPU) composite solution was coated on cotton and polyester fabrics with various coating areas to examine their applications in electrical heating fabrics for use in various areas. The graphene/WPU composites were prepared with 25 wt% WPU, and 0, 4, 8, and 16 wt% graphene. The graphene/WPU composite was coated on cotton and polyethylene terephthalate (PET) fabrics with a double plane using the knife-edge method. Fabric heating elements were fabricated with dimensions of $10.0cm{\times}10.0cm$, $7.5cm{\times}7.5cm$, $5.0cm{\times}5.0cm$, and $2.5cm{\times}2.5cm$, respectively, so that they could be applied in a variety of applications after coating. On examining the morphology, it was found that, as the content of the graphene increased, the surface of the coated fabric became smooth and uniform. The surface resistivity increased as the graphene contents increased and slightly increased with decreasing coating area. The surface temperature of the 16 wt% graphene/WPU composite coated on the fabric heating elements of $10.0cm{\times}10.0cm$ and $2.5cm{\times}2.5cm$ area on cotton were 24.5 and $52.3^{\circ}C$, respectively, and on PET fabrics 33.2 and $78.3^{\circ}C$, respectively. It was confirmed that the electrical heating properties were improved because the friction of the moving charge increased as the area of the samples decreased.

Quench Development in Coated Conductors

김혜림,박충렬,임성우,유승덕,오성용,현옥배,Kim, H.R.,Park, C.R.,Yim, S.W.,Yoo, S.D.,Oh, S.Y.,Hyun, O.B. The Korean Superconductivity Society 2009 Progress in superconductivity Vol.10 No.2

We measured and analyzed the quench development in coated conductor(CC) tapes. The CC was grown on hastelloy substrates and has an Ag protection layer. The tapes were subjected to simulated AC fault currents for quench development measurement. They were immersed in liquid nitrogen during the experiment. The quench resistance increased rapidly first, and the increase slowed down afterwards. It increased linearly with applied voltage at lower voltages, and depended less strongly on applied voltage at higher voltages. The resistance was compared with that of Au/YBCO films grown on sapphire substrates, and found to increase more monotonously than the latter. Data were analyzed quantitatively with the concept of heat transfer within the tape and the surrounding liquid nitrogen. A heat balance equation was derived and solved, taking into consideration temperature dependence of thermal parameters of the tapes. Solutions, together with values of thermal parameters taken from the literature, explained the data well. Cooling by liquid nitrogen affected the quench development considerably at lower applied voltages. Dependence on applied voltages could be also understood quantitatively.