200 GeV/핵자 유황이온과 핵건판핵의 충돌에 의해 생성된 헬륨 파쇄핵의 극한파쇄 연구

김동철,송진섭,윤천실,정성헌,박인곤,김종오,김철수,김태연,이승희,조재희,천병구,김재률,김준원,김태익,박명렬,장한일,임인택 慶尙大學校 기초과학연구소 1992 基礎科學硏究所報 Vol.8 No.-

고에너지 중이온 원자핵과 핵건판의 충돌에서, 200GeV/핵자 유황이온에 의해 생성된 파쇄 헬륨핵(Z=2)의 실험실계의 방출각 분포는 표적핵에 무관한 회귀공식. dN=exp[a+k exp(η-y_b)]d[exp(η-y_b)]로 잘 표현된다. 여기에서 의사신속도 η=-ln[tan(θ/2)]이고, y_b는 실험실계의 입사입자(^32S)의 신속도이다. 이 공식에 의한 적합에서 k=-0.057±0.008로 얻어진다. 즉, 핵건판과 고에너지 중이온의 충돌에서 파쇄 헬륨핵의 exp(η-y_b)의 분포는 "극한파쇄" 현상을 잘 설명하고 있다. The angular distribution of emission angle θ of helium (Z=2) produced in the collisions of incident particles of 200 GeV/nucleon ^32S in nuclear emulsion is well expressed by dN=exp[a+k exp(η-y_b)]d[exp(η-y_b)] where the pseudorapidity is η=-ln[tan(θ/2)], the laboratory system primary rapidity is y_b, and k=-0.057+0.008. The shape of this frequency of occurrence distributions in terms of exp(η-y_b) attests to the validity of the concept of "limiting fragmentation" for helium projectile fragments produced in the projectile fragmentation regions of heavy ion collisions in nuclear emulsion.

Cellulase-amyloglucosidase와 효모의 가스생성법에 의한 사료의 에너지가 측정에 관한 연구

김영길,이광목,김욱 東亞大學校生命資源科學大學附設 農業資源硏究所 1993 農業生命資援硏究 Vol.2 No.2

粗飼料와 濃厚飼料를 混合한 飼料의 營養價를 Cellulase와 Amyloglucosidase, 酵母를 利用한 가스 生成法에 의하여 消化率과 TDN을 測定할 수 있는 方法을 確立하고자 本 硏究를 實施한 實驗 結果는 다음과 같다. 1. Cellulose 加水分解 酵素인 Trichoderma viride cellulase의 最適 活性 pH는 4.5-4.8이었으며 pH가 5.0보다 높을 때에는 活性이 急激히 저하하였다. 2. Cellulose 加水分解시 Trichoderma viride celulase의 溫度의 의한 影響은 50℃에서 最大 活性을 나타내었으며, 40℃에서는 活性이 92%정도로 나타났다. 3. Trichoderma viride-aspergillus niger 混合, cellulase 使用時의 가스 生成量은 Trichoderma viride cellulase 使用時 가스 生成量 보다 20-30% 높게 나타났으므로 cellulose 加水分解時 Trichoderma viride-aspergillus niger 混合 cellulase를 使用하는 것이 더욱 效果的일 것으로 思料된다. 4. 포도당(X)과 가스 生成量(Y)과의 關係는 Y=6.82+165X의 回歸式과 相關係數는 0.92로서 高度의 有意性(P<0.01)이 있었다. 5. Trichoderma viride cellulase 使用時 가스 生成量(X)과 乾物 消化率(Y)과의 關係는 Y=29.9+1.13X(r=78**)의 回歸式을 나타내었고, Trichoderma viride-aspergillus niger 混合 vellulase 使用時 가스 生成量(X)과 乾物 消化率(Y)과의 關係는 Y=28.9+0.88X(r=0.82**)의 回歸式을 나타내었다. Trichoderma viride cellulase 使用時 보다 Trichoderma viride-aspergillus niger 혼합 cellulase 사용시 相關係數가 더 높았다. 6. 가스 生成量(X)과 TDN(Y)과의 關係는 Y=35.8+0.585X의 回歸式과 相關係數 0.93으로서 高度의 有意性을 나타내었고, TDN(X)과 가스 生成量(Y)과의 關係는 Y=1.68X-59.6의 回歸式을 나타내었다. The experiment was conducted to establish the gas production method by cellulase, amyloglucosidase and yeast to determine the digestibility and energy value(TDN) of feedstuffs. The results obtained were summarized as follows; 1. The highest activity of Trichoderma viride cellulase was shown at pH 4.8 and the activity of the cellulase decreased rapidly at higher pH than 5.0. 2. The highest activity of Trichoderma virie cellulase was shown at 50℃ and the activity at 40℃ was approximately 92% compared with that at 50℃. 3. The mixed celllulases of Trichoderma viride and Aspergillus nigher produced more gas than Trichoderma viride cellulase when incubated with feedstuffs and were identified to be more effectively used for gas production method. 4. The regression equation of gas production(Y) on glucose production (X) was Y=6.82+165X with significant correlation coefficient of 0.92. 5. The regression equation of DMD(Y) on gas production(X) was Y=29.9+1.13X(r=0.78) with Trichoderma viride cellulase and Y=28.9+0.88X (r=0.82) with both Trichoderma viride and Aspergillus niger cellulase. 6. The regression equation of TDN(Y) on gas production(X) was Y=35.8+0.58X with significant correlation coefficients of 0.93 and in conclusion energy value of feedstuffs can be estimated by gas production method.

돼지 卵子의 透明帶에 대한 單一클론抗體生産과 그 特性에 關한 硏究

金鐘培,劉永春,金昌圭,權五中,鄭盛元,鄭吉生 건국대학교 동물자원연구센터 1991 動物資源硏究誌 Vol.16 No.-

本 試驗은 單一클론抗體의 강한 特異性과 抗體性質의 不變性을 이용하여 發生學的 側面에서 哺乳動物 卵子의 透明帶의 機能과 構造를 이해하고, 또한 種特異的인 精子 受容體의 存在 및 生化學的 構造를 규명하기 위한 기초연구로서, 돼지 卵子의 透明帶를 免疫原으로 하여 BABL/c 생쥐로부터 單一클론抗體를 생산하고 그 특성을 구명하였던 바 다음과 같은 결과를 얻었다. 1) 3마리의 BABL/c 생쥐(YⅠ, YⅡ, ZI)에 돼지卵子의 透明帶를 免疫化하고, 複合抗體 生成을 확인한 후 생쥐의 脾臟細胞와 Myeloma(SP2/O-Ag14)를 polyethylene glycol를 融合을 실시한 결과 각각 25.8%, 54.5% 그리고 59.7%의 融合效率을 나타내었으며, ELISQ에 의해 陽性反應을 조사한 결과 각각 17.3%, 32.6% 그리고 6.2% 陽性反應 效率을 나타내었다. 2) YI에서 강한 陽性反應을 보인 6개의 well에 대한 cloning을 실시하고 抗體檢證을 행한 결과 20.8% ∼ 48.4%의 Cloning效率과 54.6% ∼ 82%의 陽性反應 效率을 나타내었다. 3) 강한 陽性反應을 나타낸 항체에 대해 sandwich ELISA法에 의해 isotype을 決定하였던바 2E93C(YⅠ), 3E83E7(YⅠ), 4E3(YⅡ)각각 IgG₂b, IgG₂a, IgM으로 확인되었다. 4) Isotype이 決定된 2E93C9(YⅠ), 3E84E7(YⅠ), 4E3(YⅡ)의 세포를 생쥐의 腹腔에 주사하여 얻은 腹水를 indirect ELISA法에 의해 titer를 決定한 결과 모두 1:400,000 이상의 높은 titer를 나타내었다. 5) 處理區로서 單一클론抗體의 腹水와 對照區로서 normal mouse serum이 각각 2%씩 함유된 배양액속에서 난자를 배양한 후 顯徵鏡下에서 관찰했을 때 對照區에서 배양된 난자의 표면은 정상적인 형태를 나타냈으나 處理區에서 배양된 卵子는 표면에 뚜렷한 沈澱層을 형성하였다. 6) 處理區와 對照區 卵子를 Rabbit anti-mouse IgG-FITC가 1% 함유된 배양액속에서 배양하고 洗滌한 후 螢光顯徵鏡下에서 관찰한 바 處理區의 卵子는 透明帶 주위에서 螢光이 나타났으나, 對照區에서는 나타나지 않았다. This study was carried out ot produce and characterize monoclonal antibodies against porcine zona pellucida, and undertaken as a basic study to develop immunocontraceptive vaccine and to investigate the function of zana pellucida in early fertilization process. The results obtained were summarized as follows: 1. Spleen cells of three BALB/C mice(YⅠ, YⅡ and ZI) which were immunized with porcine zona pelucida were fused with myeloma cells(SP2/O-Ag14) by polyethylene glycol. At the result of fusion, fusion efficiency was 25.8 , 54.5% and 59.7% and positive efficiency 17.3%, 32.6% and 6.2%, respectively. 2. Cloning efficiency was shown to be from 20.8% to 48.4% and positive efficiency of them were 54.6% to 82%. 3. Sub-isotypes of three strong positive antibodies, 2E93C(YⅠ), 3E83E7(YⅠ) and 4E3(YⅡ) were determined by sandwich ELISA method and shown to be as IgG2b, IgH2a and IgM, respectively. 4. The titers of three ascitic fluids containing antibodies, 2E93C9(YⅠ), 3E84E7(YⅠ) and 4E3(YⅡ) were determined by indirect ELISA and all of them showed above 1:400,000. 5. The layer of precipitate was observed on the zona incubated with medium containing 2% ascitic fluid of monoclonal antibody while the eggs treated with 2% normal mouse serum did not. 6. Porcine eggs incubated with medium containing 2% ascitic fluid of monoclonal antibody and followed by subsequent incubation with Rabbit anti-mouse IgG-FITC conjugate showed strong fluorescent light on the zona surface while the zona of normal mouse serum-treated eggs did not show fluorescence.

딥러닝 기법을 이용한 전해가공의 홀가공 특성 분석

최승건(S. G. Choi),김준영(J. Y. Kim),이은상(E. S. Lee) 한국생산제조학회 2019 한국생산제조시스템학회 학술발표대회 논문집 Vol.2019 No.5

Haplotype and mutation analysis for newly suggested Y-STRs in Korean father-son pairs

Oh, Y.N.,Lee, H.Y.,Lee, E.Y.,Kim, E.H.,Yang, W.I.,Shin, K.J. Elsevier Science 2015 FORENSIC SCIENCE INTERNATIONAL GENETICS Vol.15 No.-

In this study, 363 Korean father-son haplotype transfers in 351 families were analyzed using an in-house multiplex PCR system for 14 Y-STRs (DYS385a/b, DYF387S1, DYS391, DYS449, DYS460, DYS481, DYS518, DYS533, DYS549, DYS570, DYS576, DYS627 and DYS643), that included 11 loci newly added to the PowerPlex Y23 system or the Yfiler Plus system. The Y-STRs showed gene diversity values ranging from 0.2499 to 0.9612; the multicopy Y-STR loci DYS385 and DYF387S1 had high gene diversity of 0.9612 and 0.9457, respectively. In addition, DYF387S1, which has two copies, showed three alleles in seven individuals, and micro-variant alleles were observed in 14 individuals at four loci (DYS448, DYS518, DYS570 and DYS627). Among 351 haplotypes for the 11 newly added Y-STRs, 350 different haplotypes were observed, with an overall haplotype diversity of 0.9999 and discrimination capacity of 99.72%. In 363 haplotype transfers from 351 pedigrees, 29 single-step mutations were observed at 11 Y-STRs. Locus-specific mutation rate estimates varied from 0.0 to 1.93x10<SUP>-2</SUP>, with an average estimated mutation rate of 6.66x10<SUP>-3</SUP>. Two father-son pairs had mutations at two different loci in 11 Y-STRs. The number of pairs with mutations at multiple loci increased to five when the mutation event was investigated for haplotype transfer at 28 Y-STRs including 17 Yfiler loci and 11 Y-STRs examined in this study: four father-son pairs had mutations at two loci, and one pair had mutations at three loci. Overall, mutations were frequently observed at DYS449, DYS576 and DYS627 loci, which are known to be rapidly mutating Y-STRs. Mutation rate estimates at most loci were not significantly different from rates in other populations, but estimates for DYF387S1, DYS518 and DYS570 were considerably lower in the Korean population than in other populations.

Analysis of 22 Y chromosomal STR haplotypes and Y haplogroup distribution in Pathans of Pakistan

Lee, E.Y.,Shin, K.J.,Rakha, A.,Sim, J.E.,Park, M.J.,Kim, N.Y.,Yang, W.I.,Lee, H.Y. Elsevier Science 2014 FORENSIC SCIENCE INTERNATIONAL GENETICS Vol.11 No.-

We analyzed haplotypes for 22 Y chromosomal STRs (Y-STRs), including 17 Yfiler loci (DYS19, DYS385a/b, DYS389I/II, DYS390, DYS391, DYS392, DYS393, DYS437, DY438, DYS439, DYS448, DYS456, DYS458, DYS635 and Y-GATA-H4) and five additional STRs (DYS388, DYS446, DYS447, DYS449 and DYS464), and Y chromosomal haplogroup distribution in 270 unrelated individuals from the Pathans residing in the Federally Administered Tribal Areas and the North-West Frontier Province of Pakistan using in-house multiplex PCR systems. Each Y-STR showed diversities ranging from 0.2506 to 0.8538, and the discriminatory capacity (DC) was 73.7% with 199 observed haplotypes using 17 Yfiler loci. By the addition of 5 Y-STRs to the Yfiler system, the DC was increased to 85.2% while showing 230 observed haplotypes. Among the additional 5 Y-STRs, DYS446, DYS447 and DYS449 were major contributors to enhancing discrimination. In the analysis of molecular variance, the Pathans of this study showed significant differences from other Pathan populations as well as neighboring population sets. In Y-SNP analysis, a total of 12 Y chromosomal haplogroups were observed and the most frequent haplogroup was R1a1a with 49.3% frequency. To obtain insights on the origin of Pathans, the network analysis was performed for the haplogroups G and Q observed from the Pathans and the Jewish population groups including Ashkenazim and Sephardim, but little support for a Jewish origin could be found. In the present study, we report Y-STR population data in Pathans of Pakistan, and we emphasize the need for adding additional markers to the commonly used 17 Yfiler loci to achieve more improved discriminatory capacity in a population with low genetic diversity.

Investigation into the sequence structure of 23 Y chromosomal STR loci using massively parallel sequencing

Kwon, S.Y.,Lee, H.Y.,Kim, E.H.,Lee, E.Y.,Shin, K.J. Elsevier Science 2016 FORENSIC SCIENCE INTERNATIONAL GENETICS Vol.25 No.-

Next-generation sequencing (NGS) can produce massively parallel sequencing (MPS) data for many targeted regions with a high depth of coverage, suggesting its successful application to the amplicons of forensic genetic markers. In the present study, we evaluated the practical utility of MPS in Y-chromosome short tandem repeat (Y-STR) analysis using a multiplex polymerase chain reaction (PCR) system. The multiplex PCR system simultaneously amplified 24 Y-chromosomal markers, including the PowerPlex<SUP>®</SUP> Y23 loci (DYS19, DYS385ab, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS481, DYS533, DYS549, DYS570, DYS576, DYS635, DYS643, and YGATAH4) and the M175 marker with the small-sized amplicons ranging from 85 to 253bp. The barcoded libraries for the amplicons of the 24 Y-chromosomal markers were produced using a simplified PCR-based library preparation method and successfully sequenced using MPS on a MiSeq<SUP>®</SUP> System with samples from 250 unrelated Korean males. The genotyping concordance between MPS and the capillary electrophoresis (CE) method, as well as the sequence structure of the 23 Y-STRs, were investigated. Three samples exhibited discordance between the MPS and CE results at DYS385, DYS439, and DYS576. There were 12 Y-STR loci that showed sequence variations in the alleles by a fragment size determination, and the most varied alleles occurred in DYS389II with a different sequence structure in the repeat region. The largest increase in gene diversity between the CE and MPS results was in DYS437 at +34.41%. Single nucleotide polymorphisms (SNPs), insertions, and deletions (indels) were observed in the flanking regions of DYS481, DYS576, and DYS385, respectively. Stutter and noise ratios of the 23 Y-STRs using the developed MPS system were also investigated. Based on these results, the MPS analysis system used in this study could facilitate the investigation into the sequences of the 23 Y-STRs in forensic genetics laboratories.

식물성 세포벽에 함유된 Ca과 P의 Rooster에 있어서 소화율에 관한 연구

김종쾌,김영규,김대진 東亞大學校 1992 東亞論叢 Vol.29 No.1

본 연구는 綠葉중에서 ladino clover 잎, alfalfa 잎, 칡잎, 아카시아잎, 싸리잎 등을 5월과 6월의 生育시기를 두 시기로 하여 동물 체내에서 Ca과 P 그리고 NDF에 결합된 Ca과 P의 이용성을 조사하였다. 실험에 사용된 동물은 10개월된 재래 숫탉(rooster)으로서 이들 綠葉은 체중 kg당 약 1% 강제 급여(forced feeding) 한 후 36시간 동안의 배설물을 채취하였으며, 이와 동시에 대사성 糞과 내인성 뇨로 분비되는 Ca과 P을 보정하기 위하여 36시간 절식시켜서 배설물을 채취하였다. 생체내 Ca과 P의 이용성 실험은 세번 반복을 하였으며, 대사성 분과 내인성 뇨 실험도 다섯번 반복을 실시하였는데 그 결과를 요약하면 다음과 같다. 1. NDF 含量에 있어서 綠葉(ladino clover잎, alfalfa 잎, 칡잎, 아카시아잎, 싸리잎)은 5월 예취가 30.42%-37.28% 범위였으며, 6월 예취는 45.43-59.36% 점위로 生育이 進行됨에 따라 增加하였다. (p<0.05). 2. 眞正 DM 消化率(TDMD)에 있어서 綠葉은 5월 예취가 24.75-47.24%의 범위였으며, 6월 예취는 23.31-42.20% 범위로 生育이 進行됨에 따라 減少하였다(p<0.01). 3. 眞正 이용 Ca(TACa)에 있어서 綠葉은 5월 예취가 7.94-56.65%의 범위였으며, 6월 예취는 4.02-51.09% 범위로 生育이 進行됨에 따라 alfalfa 잎은 增加하였으나, ladino clover 잎은 減少하였고(p<0.05), 칡잎, 아카시아잎은 뚜렷한 변화가 없었다. 4. 眞正 이용 P(TAP)에 있어서 綠葉은 5월 예취가 8.52-4.89%의 범위였으며, 6월 예취는 24.86-42.6%로 生育이 進行됨에 따라 增加하였으나 ladino clover 잎에서는 減少하였다(p<0.05). 5. NDF에 결합된 Ca의 이용율에 있어서 綠葉은 5월 예취가 4.04-15.80%의 범위였으며, 6월 예취는 3.23-8.11%로 生育이 進行됨에 따라 減少하였으나 (p<0.05), ladino clover 잎, 싸리잎은 뜨렷한 변화가 없었다. 6. NDF에 결합된 P의 이용율에 있어서 綠葉은 5월 예취가 3.97-17.01% 범위였으며, 6월 예취는 4.06-14.93%로 生育이 進行됨에 따라 ladino clover잎, 칡잎, 아카시아잎은 減少하였으나(p<0.05), la-dinl clover 잎과 싸리잎은 뚜렷한 변화가 없었다. 7. 綠葉에 있어서 TDMD(Y) 含量과 NDF 含量(X) 사이에는 Y=53.5-0.42X의 回歸式과 r=-0.50의 相關關係를 보였다(p<0.01). 8. Ladinl clover 잎의 P-D(Y)와 P 含量(X) 사이에는 Y=84.5-85.1X의 回歸式과 r=-0.91의 相關關係를 보였다(p<0.01). 9. Alfalfa 잎의 Ca-D(Y)와 Ca含量(x) 사이에는 Y=18.9+13.0X의 回歸式과 r=0.99의 相關關係를 보였다(p<0.01). 10. 칡잎의 P-D(Y)와 P含量(X) 사이에는 Y=139-368X의 回歸式과 r=-0.95의 相關關係를 보였다(p<0.01). 11. 아카시아잎의 P-D(Y)와 P含量(X) 사이에는 Y=87.8-229X의 回歸式과 r=-0.98의 相關關係를 보였다(p<0.01). 12. 싸리잎의 Ca-D含量(Y)과 Ca含量(X) 사이에는 Y=17.9-12.8X의 回歸式과 r=-0.83의 相關關係를 보였다(p<0.01). This experiment was conducted to evaluate the Ca and P bioavailabilities of green leaf meal by roos-ter. The cell wall binding Ca and P of green leaf meal such as ladino clover, alfalfa, kudzu, acacia and bush clover were collected by two stage of cutting for May and June 1990. Rooster employed in the present experiment were fed about one percentage of body weight by forced feeding of ingredient. Collection of excreta as fed after 36 hous and did not given ingredient during the determinate of urinary endogenous and metabolic fecal Ca, P and excreta for 36 hours. The feeding experiment was conducted triplication for bioassay of Ca and P and was give five repli-cation for composition of metabolic and endogenous material. The results obtained are summarized as follows : 1. The contents of neutral detergent fiber(NDF) of several green leaves meal were ranged from 30.42% to 37.28% for cutting of May and were ranged from 45.43% to 59.36% for cutting of June, there-fore NDF were decreased by abvanced stages of maturity(p<0.05). 2. The true dry matter digestibility(TDMD) of several green leaves meal were ranged from 24.57% to 42.24% for cutting of May and were ranged from 23.31% to 42.20% for cutting of June and TDMD was decreased by advanced stages of maturity(p<0.05). 3. The true available clacium(TACa) of several green leaves meal were ranged from 7.94% to 56.65% for cutting of May and were ranged from 4.02% to 51.09% for cutting of June, exception of alfalfa among other did not show increase by advanced stages of maturity(p<0.05). 4. The true avilable phosphorus(TAP) of several green leaves meal were ranged from 8.25% to 46.89% for cutting of May and were ranged from 24.86% to 42.6% for cutting of June and TAP was increased but decreased only ladino clover by advanced stages of maturity(p<0.05). 5. NDF binding of avilable calcium(NDF+Ca) of several green leaves meal were ranged from 4.04% to 15.80% for cutting of May and were ranged from 3.23% to 50 8.11% for cutting of June and they were decreased by advanced stages of maturity(p<0.05) but ladino clover and bush clover did not changed by advanced stage of maturity. 6. NDF binding of avilable phosphorus(NDF+P) of several green leaves meal were ranged from 3.97% to 17.01% for cutting of May and were ranged from 4.06% to 14.93% for cutting of June and they were decreased by advanced stages of maturity(p<0.05) but alfalfa and bush clover did not changed by advanced stage of maturity. 7. Regression equation and correlation coefficients of several green leaves meal between TDMD(Y) and NDF(X) were Y=53.5=0.42X and r=-0.50(p<0.01). 8. Regression equation and correlation coefficients of ladino clover leaf meal between digestible phos-phorus(Y) and phosphorus(X) were Y=84.5-85.1X and r=-0.91(p<0.01). 10. Regression euqation and correlation coefficients of kudzu leaf meal between digestible phosphours(Y) and phosphours(X) were Y=139-368X and r=-0.95(p<0.01). 11. Regression euqation and correlation coefficients of acacia leaf meal between digestible phosphours(Y) and phosphours(X) were Y=87.8-229X and r=-0.98(p<0.01). 12. Regression euqation and correlation coefficients of bush clover leaf meal between digestible calcium(Y) and calcium(X) were Y=17.9-12.8X and r=-0.83(p<0.05).

Effects of calcium doping on the superconducting properties of top-seeded melt growth processed Y_1.5Ba_2-xCa_xCu₃O_y superconductors

Park, S.D.,Kim, H.J.,Park, B.J.,Han, Y.H.,Jun, B.H.,Lee, J.S.,Kim, C.J. North-Holland 2011 Physica. C, Superconductivity Vol.471 No.21

The effect of calcium doping on the superconducting properties of top seeded melt growth (TSMG) processed Y<SUB>1.5</SUB>Ba<SUB>2-x</SUB>Ca<SUB>x</SUB>Cu<SUB>3</SUB>O<SUB>y</SUB> superconductors was studied in terms of calcium content (X<SUB>ca</SUB>). YBa<SUB>2-x</SUB>Ca<SUB>x</SUB>Cu<SUB>3</SUB>O<SUB>7-δ</SUB> (X<SUB>ca</SUB>=0, 0.005, 0.01, 0.02, 0.04, 0.1, 0.3) powders were synthesized by the powder calcination method. YBa<SUB>2-x</SUB>Ca<SUB>x</SUB>Cu<SUB>3</SUB>O<SUB>7-δ</SUB> powders were mixed with 0.25mole Y<SUB>2</SUB>O<SUB>3</SUB> powder and 1wt.% CeO<SUB>2</SUB> as Y<SUB>2</SUB>BaCuO<SUB>5</SUB> (Y211) refiner, and finally made into Y<SUB>1</SUB>.<SUB>5</SUB>Ba<SUB>2-x</SUB>Ca<SUB>x</SUB>Cu<SUB>3</SUB>O<SUB>y</SUB> (Y1.5)+1wt.% CeO<SUB>2</SUB> composition. The single Y123 growth on the top surface was observed up to X<SUB>ca</SUB>=0.1, while the multiple Y123 growth was observed at X<SUB>ca</SUB>≥0.1. The superconducting transition temperature (T<SUB>c</SUB>) and critical current density (J<SUB>c</SUB>) of TSMG processed Y1.5 samples were inversely proportional to X<SUB>ca</SUB>. The Y211 size increased with increasing X<SUB>ca</SUB> due to the enhancement of Y211 coarsening by calcium doping. No Y211 refining effect by CeO<SUB>2</SUB> was observed in the calcium doped samples. The T<SUB>c</SUB> and J<SUB>c</SUB> decrease by calcium doping are likely to be due to the calcium incorporation with the Y123 lattice and formation of coarse Y211 particles.

Effects of Y₂O₃ additions on the oxygen diffusion in top-seeded melt growth processed YBa₂Cu₃O_7-y superconductors

Jun, B.H.,Jung, S.A.,Park, S.D.,Park, B.J.,Han, Y.H.,Kim, C.J. North-Holland 2011 Physica. C, Superconductivity Vol.471 No.21

To understand the effect of Y<SUB>2</SUB>BaCuO<SUB>5</SUB> (Y211)/YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7-y</SUB> (Y123) interfaces on the oxygen diffusion in single grain YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7-y</SUB> superconductors, single grain Y123 superconductors with 0.05 and 0.3moles of Y<SUB>2</SUB>O<SUB>3</SUB> additions were fabricated by a top-seeded melt growth (TSMG) process. Y123 compacts with Y<SUB>2</SUB>O<SUB>3</SUB> additions were subjected to melt growth heating cycles with a cooling rate of 1<SUP>o</SUP>C/h through a peritectic temperature (1015<SUP>o</SUP>C) and then annealed at 450<SUP>o</SUP>C for 200h in flowing oxygen. The superconducting temperature (T<SUB>c</SUB>) and critical current density (J<SUB>c</SUB>) were estimated for the three different regions (top surface (s), intermediate (i) and center (c)) of samples. The amount of Y211/Y123 interface area in single grain Y123 superconductors was successfully controlled by Y<SUB>2</SUB>O<SUB>3</SUB> additions. The T<SUB>c</SUB> values of s regions were higher than those of i and c regions, which indicates the presence of more oxygen at the sample surfaces. In addition, the T<SUB>c</SUB> values of i and c regions of the Y123 sample with 0.3mole Y<SUB>2</SUB>O<SUB>3</SUB> addition were higher than those of the same regions of the Y123 sample with 0.05mole Y<SUB>2</SUB>O<SUB>3</SUB> addition due to the promoted oxygen diffusion through Y211/Y123 interfaces and other related defects. In spite of the promoted oxygen diffusion by Y<SUB>2</SUB>O<SUB>3</SUB> addition, the large T<SUB>c</SUB> difference among the regions still existed, which suggests sluggish oxygen diffusion into single Y123 grains.