• Progress in Superconductivity and Cryogenics
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• v.24 no.3
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• pp.35-40
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• 2022

To fabricate large grain YBCO bulk superconductors by melt process, Sm123 single crystal with a high melting point are mostly used as seeds. However, it also uses Y123 film deposited on MgO single crystal substrate. This study investigated the growth behavior of the Y123 grain during a melt process when single grain YBCO bulk was used as a seed. Single grain Y123 bulk was grown when the seed size was small. When the seed size was relatively large, multiple grains were grown but the grains were still large. Y123 seed crystal was completely decomposed during high temperature anneal at 1040℃ and new Y123 crystals were nucleated during a slow cooling stage below a peritectic temperature. Thereafter, newly formed Y123 crystals from the seed area are thought to grow into the Y1.8 powder compact. The crystallographic orientations of newly nucleated Y123 grains are independent of the crystallographic orientation of Y123 seed. It is thought that the crystallographic orientation of newly nucleated Y123 crystal can be controlled by using Y211-free Y123 single crystal as a seed of homo-seeding melt growth.

• Korean Journal of Materials Research
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• v.4 no.4
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• pp.428-438
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• 1994

In order to investigate the effect of $SnO_2$ on the growth of 123 phase in Y-Ba-Cu-0 system, O.1Sn-doped 123+Sn compact was coupled with Sn-free 123 compact by placing the former on the latter. In case of the coupled samples which were held at $1100^{\circ}C$ for 24hr and then at $970^{\circ}C$ for lhr, 123 phase grew from the surface of O.1Sn-doped 123+Sn compact toward the inner of Sn-free 123 compact. In case of the coupled samples which were held at $1100^{\circ}C$ for 48hr and then at $970^{\circ}C$ for lhr, it was not the 123 phase but Ba-Y-Sn grains that were observed. Ba-Y-Sn grains with a shape of bar was composed of Ba : Y : Sn=5 : 3 : 2, approximately.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.05a
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• pp.224-233
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• 2002

A common YBCO powder has been made from a mixture of Y123 and Y211 that heated at different temperatures, respectively. The synthesis temperature of Y211 is lower than Y123. If Y211 has been heated as a synthesis temperature of Y123, a particle size of it may be very coarse. It exist as one of main defects for superconductor. But We simultaneously synthesize a YBCO(its composition is (Y123+0.4Y211)+$lwt%CeO_2$) using polymeric complex method. In the YBCO, the Y123 is synthesized lower temperature than other methodes, and its crystal structure is orthorombic. For measurement of these superconducting properties, we fabricated a YBCO single crystal. The manufactured YBCO single crystal is measured a magnetic distribution device using 0.5Tesla magnet and trapped magnet fields in it are 0.2Tesla.

• Journal of the Korean Institute of Gas
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• v.18 no.5
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• pp.85-90
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• 2014

Turbo chiller is widely used for the air conditioner and uses hydrochlorofluorocarbon 123 (HCFC-123) as a refrigerant. HCFC-123 is one of the chemicals being considered as a replacement for the chlorofluorocarbons. High concentrations of HCFC-123 cause a deficiency of oxygen with the risk of unconsciousness or death, the vapour is heavier than air and may accumulate in low ceiling spaces causing deficiency of oxygen. In this study, the concentration distribution of oxygen indoor was investigated by using computational fluid dynamics(CFD) as four workers were killed in HCFC-123 gas leaks at machine room of hypermarket in 2011.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.179-185
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• 1987

Laboratory studies were conducted to evaluate safening effect of CGA 123'407 (4,6-dichloro-2-phenyl-pyrimidine) against pretilachlor, butachlor, and benthiocarb in rice plants. Butachlor and benthiocarb at 50 ppm or higher concentrations significantly inhibited rice growth and pretilachlor gradually inhibited growth of rice plants with increase in concentration starting from 0.5 ppm. CGA 123'407 at 0.1 ppm or higher concentrations was effective in reducing injury of rice plants when butachlor and benthiocarb were applied at rate of 10 ppm. Rice injury from pretilachlor at 10 ppm was also reduced by addition of CGA 123'407 at 0.25 ppm or higher concentrations Herbicidal activity of pretilachlor, butachlor, and benthiocarb was not affected by mixture treatments of CGA 123'407.

• Journal of the Korean Chemical Society
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• v.36 no.4
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• pp.477-484
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• 1992

Using semiempirical molecular orbital method, ASED-MO of extended Huckel Theory, we were investigated chemical bonds and electronic properties of Cu atom in a chain and a layer for Y123 and Y124 superconductors from VEP (valence electron population), DOS (density of state), and COOP (crystal orbital overlap population). In order to investigate environmental effects of Cu atom for Y123 and Y124 superconductors, we introduced charged cluster models with point charge and without point charge into our calculations. As a result of ASED-MO calculations, the Cu atom in the layer acts as electron acceptor and the Cu atom in the chain acts as electron donor for Y123 and Y124 superconductors. The oxidation state of Cu atom for Y123 and Y124 superconductors without point charge is higher in the chain than in the layer. The oxidation state of Cu atom in the layer for Y123 superconductor is higher than that in the layer for Y124 superconductor. The Cu atom in the layer and the chain for Y123 superconductor does not largely affect on the environmental effect. However, the Cu atom in the layer and the chain for Y124 superconductor does largely affect on it. Also, electron population and chemical bonding of Cu1-O4, Cu2-O4, and Cu1-Cu2 for Y123 superconductor are far different from Y124 superconductor.

• The Korean Journal of Nuclear Medicine
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• v.32 no.1
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• pp.50-60
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• 1998

I-123 labelled fatty acids are suitable for investigation of regional myocardial metabolism, so they are on the clinical trial. However, the precise properties of these materials are not characterized yet. We have synthesized phenylpentadecanoic acid and labeled this compound with I-123. The purpose of this study was to examine the stability, biodistribution, metabolism and SPECT imaging of [I-123]15-(p-iodophenyl)pentadecanoic acid(I-123-IPPA) that we made. The stability test of I-123-IPPA in serum of rat, mouse and human showed no free I-123 after 1 hour. In biodistribution study in mice for various time intervals after injection(5, 10, 15, 30, 60 minutes), uptake in myocardium was 14.5%ID/g(5 min), and 1.9%ID/heart(5 min), while uptake in muscles was 2.6%ID/g(5 min). Myocardium to blood ratio and myocardium to lung ratio increased for 5 min after injection and then decreased rapidly. Chromatographic data of rat blood and urine showed that little PPA was found in blood and urine at 15-20 min after injection. The myocardial I-123-IPPA SPECT images of a dog with myocardial infarction showed defects similar to those of Tc-99m-MIBI and F-18-FDG. These data suggest that I-123-IPPA is quite stable in vitro and shows favorable biodistribution in mice. SPECT imaging with I-123-IPPA demonstrated infarct zone as photon defect in dog model of myocardial infarction. I-123-IPPA may be used for the evaluation of fatty acid metabolism in clinical trials in Korea.

• The Korean Journal of Nuclear Medicine
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• v.34 no.5
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• pp.403-409
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• 2000

Objectives: Due to the heterogeneous receptor distribution and changes of receptor status over time, the biochemical measurement of estrogen receptor status of biopsy specimens is not sufficient to diagnose breast cancer. As a result, I-123 labeled estradiols have been applied for the diagnosis. The purpose of this study was to develop a suitable radioligand for imaging estrogen receptor-positive human breast tumors. Methods: Among the various estradiol derivatives, $17{\alpha}-[^{123}I]$iodovinyl estradiol ($[^{123}I]$IVE) has been prepared from $17{\alpha}$-ethynyl estradiol. Labeling of $E-17{\alpha}-[^{123}I]$iodovinyl estradiol (E-$[^{123}I]$IVE) was carried out using peracetic acid with $[^{123}I]NaI\;and\;Z-[^{123}I]IVE$ labelling was archived using chloamine-T/HCl solution with $[^{123}I]$NaI. Labeling yield was determined by silica thin-layer chromatography (TLC) and radiochemical purity was measured by high performance liquid chromatography (HPLC). The biodistribution of E-$[^{123}I]$IVE was measured in immature female rats at 60 min, 120 min and 300 min after injection. Results: The labeling yield of two isomers was 92% and 94% ($E-[^{123}I]IVE\;and\;Z-[^{123}I]IVE$, respectively). The radiochemical purity was more than 98% after purification. The highest uptake was observed at 120 min in uterus (3.11% ID/g for E-$[^{123}I]$IVE). Conclusion: These results suggest the possibility of using E-$[^{123}I]$IVE as an imaging agent for the evaluation of the evaluation of the presence of estrogen receptor in patients with breast cancer.

• The Korean Journal of Nuclear Medicine
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• v.30 no.1
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• pp.19-34
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• 1996

[ $[^{123}I]{\beta}$ ]-CIT [$2{\beta}$-carbomethoxy-$3{\beta}$-(4-iodophenyl)tropane]는 도파민 운반체 (dopamine transporter)에 특이결합하며 $[^{123}I]{\beta}$-CIT의 도파민 운반체 결합정도는 파킨슨병에서 도파민 뉴우런의 변성정도를 반영하는 것으로 제안되어 왔다. 이 연구의 주요 목적은 파킨슨병 환자에서 $[^{123}I]{\beta}$-CIT SPECT를 이용하여 측정된 $[^{123}I]{\beta}$-CIT의 선조체 결합지표들이 질병의 임상적 진행정도를 반영하는지를 검토하고, 간편화된 조직방사능비가 $[^{123}I]{\beta}$-CIT의 결합정도를 나타내는 정량적 지표로 이용될 수 있는지를 검증하는 것이었다. 파킨슨병 환자 30명($59{\pm}9$세, 평균${\pm}$표준편차: Hoehn-Yahr stage 1-3)과 정상인 6명 ($58{\pm}5$세)을 대상으로 $[^{123}I]{\beta}$-CIT SPECT 영상을 얻었다. $[^{123}I]{\beta}$-CIT 선조체 결합의 정량적 지표로서 (선조체 방사능-소뇌방사능)/소뇌방사능 비(specific binding ratio, SBR)와 추적자역학모델을 이용하여 측정한 선조체 결합능(binding potential)($k_3/k_4$)을 구하였다. 파킨슨병 환자에서 $[^{123}I]{\beta}$-CIT의 선조체 결합역학은 정상인에 비하여 현저하게 느렸으며 그 결합지표들은 정상인에 비하여 뚜렷하게 낮았다. 한편, 편측파킨슨병 환자에서 $[^{123}I]{\beta}$-CIT 결합은 증상 반대쪽 선조체 뿐만 아니라 같은 쪽 선조체에서도 정상인에 비해 유의하게 감소되어 있었다. 파킨슨병 환자에서 $[^{123}I]{\beta}$-CIT 투여 후 24시간의 선조체 SBR 및 최대 SBR, 선조체 결합능은 모두, 유병기간, Hoehn-Yahr stage, UPDRS(Unified Parkinson's Disease Rating Scale) 총점, UPDRS 운동점수, UPDRS 일상활동점수와 유의한 상관관계를 나타내었다. 24시간 선조체 SBR과 최대 SBR은 선조체 결합능과 우수한 상관관계를 보였다. 이상의 결과로부터 $[^{123}I]{\beta}$-CIT의 선조체 결합은 파킨슨병의 진행정도를 나타내는 지표로 이용될 수 있다. 또 $[^{123}I]{\beta}$-CIT 투여 후 24시간 영상으로부터 얻은 간편화된 조직방사능 비는 $[^{123}I]{\beta}$-CIT의 결합정도를 정량적으로 반영한다. $[^{123}I]{\beta}$-CIT SPECT는 파킨슨병의 조기진단 및 진행 추적에 임상적으로 유용할 것으로 판단된다.

• The Korean Journal of Nuclear Medicine
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• v.30 no.3
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• pp.372-378
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• 1996

In the case of $^{123}I$ from the $^{124}Te$(p,2n)reaction, the radionuclidic impurity is the high-energy gamma-emitting $^{124}I$, which interferes greatly with nuclear medicine images. The choice of a collimator can affect the quality of clinical SPECT images of [I-123]MIBG, [I-123] ${\beta}$-CIT, or [I-123]IPT. The tradeoffs that two different collimators make among spatial resolution, sensitivity, and scatter were studied by imaging a line source at 5cm, 10cm, 15cm distance using a number of plexiglass sheets between source and collimator, petri dish, two-dimensional Hoffman brain phantom, Jaszczak phantom, and three-dimensional Hoffman brain phantom after filling with $^{123}I$. (FWHM, FWTM, Sensitivity) for low-energy ultrahigh-resolution parallel - hole (LEUHRP) collimator and medium- energy general - purpose (MEGP) collimator were measured as (9.27mm, 61.27mm, $129CPM/{\mu}Ci$) and (10.53mm, 23.17mm, $105CPM/{\mu}Ci$), respectively. The image quality of two-dimensional Hoffman brain phantom with LEUHRP looked better than the one with MEGP. However, the image quality of Jaszczak phantom and three-dimensional Hoffman brain phantom with LEUHRP looked much worse than the one with MEGP because of scatter contributions in three-dimensional imaging situation. The results suggest that the MEGP is preferable to LEUHRP for three-dimensional imaging studies of [I-123]MIBG, [I-123] ${\beta}$-CIT, or [I-123]IPT.