• 한국초전도학회:학술대회논문집
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• v.14
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• pp.75-75
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• 2004

• 한국초전도학회:학술대회논문집
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• v.15
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• pp.48-48
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• 2005

• Analytical Science and Technology
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• v.10 no.3
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• pp.203-208
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• 1997

Barium titanyl oxalate(BTO) was precipatated by utilizing the thermal decomposition of dimethyl oxalate in acidic aqueous solution having $BaCl_2$ and $TiCl_4$. Particle morphology of BTO was influeneced by the various experimental factors. i.e.. the faster rate to nucleation with higher temperature and the higher ratio of [DMO]/[$Ba^{2+}+Ti^{4+}$] was found to correspond to the faster rate of transformation of particle size distribution from unimodal to broad unimodal through bimodal. The BT powder obtained by calcination at $900^{\circ}C$ in air consists of larger particles than BT generated by general coprecipitation method and shows tetragonal symmetry. The stirring during reaction was also found to have much effect upon characteristics of BTO and BT.

• The Journal of Korean Physical Therapy
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• v.11 no.2
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• pp.81-92
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• 1999

중추신경계의 미주신경동쪽핵(DMV)내 유사핵분열후 신경세포로 외래 유전자를 전달하는 매개체로서 pseudorabies 바이러스(PRV)의 유전자 조작기술은 흰쥐의 결장내로 PRV를 주입시킨 후 복잡한 신경로 추적에 관한 연구에서 하나의 바이러스에 의해 얻어지는 것보다 더욱 유용한 결과산출이 가능하게 하였다. 본 연구에서는 흰쥐의 생체내 실험모델로 하나의 바이러스 또는 이중 바이러스 주입에 PRV의 유전자 조작된 2종 바이러스를 사용하였다. 이 2종의 바이러스는 PRV의 Bartha 종에서 유래되었지만 면역조직화학적으로 검출할 수 있는 동일한 유전산물을 산출할 수 있도록 구성되었다. PRV-BaBlu는 PRV 게놈의 Us 구역 중 gC 자리에 lacZ 유전자를 삽입하여 산출되었는데 $\beta-galactosidase$ 발현은 이 바이러스에 감염된 신경원의 독특한 표시자로 나타났다. PRV-D는 2가지 단계에 의해 조성되었는데 첫째, PRV-Bartha의 Us 구역의 일부 유전자를 제거하고, 야생형인 PRV-Be DNA로 복구시켰는데 이로써 PRV-D는 PRV-Bartha 또는 PRV-Bablu에 존재하고 있지 않는 외피 당단백질인 gE와 gI를 지니게 되었다. 본 연구의 결과는 다음과 같았다. 첫째, PRV-D의 개별적 접종에 의해 얻어진 감염은 PRV-BaBlu에 의한 동일 신경회로의 감염보다 유의하게 빨랐다. 둘째, 유전자 조작된 PRV의 변이종은 변이종 상호간 및 부모 바이러스와 상이하였다. PRV-D는 PRV-Bartha 또는 PRV-BaBlu보다 감염독성이 더 강했고, PRV-BaBlu는 PRV-Bartha보다 감염독성이 약했다. 셋째, 결장을 지배하는 미주신경동쪽핵내 신경원은 변이종 바이러스들을 동시에 접종하였을 경우 이중감염을 나타내었다.

• Journal of the Korean Chemical Society
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• v.26 no.4
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• pp.229-234
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• 1982

Using solution technique, sulfur in the sulfide ore was indirectly determined by X-ray fluorescence spectrometry. The sample was dissolved with the mixed solution of B$r_2$ and HN$O_3$, and Si$O_2$, a major constituent, was repelled from the solution by HF treatment several times, B$a^{2+}$ solution was added to the solution to precipitate the S$O^4_{2-}$ ion as BaS$O_4$. Measuring the fluorescent X-ray intensity of excess Ba2+ ion in the filtrate, the content of sulfur in the original ore was back-calculated. Comparing the results by this method with the gravimetric method, the mean difference was ${\pm}1.7%$ in the range of 20 to 40% of sulfur content and the method was tolerably reproducible.

• Korean Journal of Weed Science
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• v.11 no.1
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• pp.68-73
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• 1991

This study was conducted to determine the appropriate culture conditions for developing photoautotrophic cells from tobacco using plant growth regulators, sucrose and light condition in LS medium. The greatest callus induction was observed in the LS medium supplemented with $10^{-5}$ M NAA and $10^{-4}$ M BA, showing 3.08 g of callus fresh weight determined at 30 days after incubation. The highest chlorophyll content of callus was obtained in the LS medium supplemented with $10^{-5}$M NAA and $10^{-6}$ M BA, showing 28.42${\mu}g/g$. In both light and dark conditions, callus induction increased as the concentration of sucrose increased from 0.5%to 3.0%. In particular, in the light condition, the greatest callus induction was made in the LS medium supplemented with 2% sucrose. On the other hand, the heighest chlorophyll content was observed at 0.5% sucrose and chlorophyll wasn't induced in dark condition. The chlorophyll content of callus cultured in LS medium containing 0.75% sucrose was similar to 1% sucrose, as far as the chlorophyll content of callus was concerned.

• 한국초전도학회:학술대회논문집
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• v.13
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• pp.32-32
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• 2003

• The Journal of the Petrological Society of Korea
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• v.26 no.3
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• pp.271-280
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• 2017

The Dongcheondong granite is alkali feldspar granite in Dongcheondong, Gyeongju. The granite is coarse grained and consists of alkali feldspar, quartz, amphibole, and biotite. Alkali feldspar is perthitic orthoclase and quartz often shows undulatory extinction. Plagioclase often shows albite twins, and biotite and amphibole emplace as interstitial minerals. The Dongcheondong granite is plotted in A-type area having high ($Na_2O+K_2O)/Al_2O_3$ and low (MgO+CaO)/FeOT ratio. The Dongcheondong A-type granite has higher $SiO_2$, $Na_2O$, $K_2O$, Zr, Y, and REE contents (except for Eu) and lower $TiO_2$, $Al_2O_3$, CaO, MgO, Sr, Ba, and Eu contents than I-type granites in Gyeongsang Basin. These results show that the geochemical characteristics of the Dongcheondong A-type granite are distinguished from I-type granite in Gyeongsang Basin. A-type granite in the Dongcheondong is thought to has been generated by partial melting of I-type tonalite or granodiorite.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.2
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• pp.147-150
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• 2020

Relatively pure YBCO was first synthesized by heating a mixture of metal carbonates at temperatures between 1,000 and 1,300 K, resulting in the reaction: 4BaCO₃+Y₂(CO₃)₃+6CuCO₃+(1/2_-x)O₂ → 2YBa₂Cu₃O_7-x+1/3CO₂. Modern syntheses of YBCO use the corresponding oxides and nitrates. The superconducting properties of YBa₂Cu₃O_7-x are sensitive to the value of x, i.e., its oxygen content. Only those materials with 0≤x≤0.65 are superconducting below Tc, and when x ~ 0.07, the material superconducts at the highest temperature, i.e., 95 K, or in the highest magnetic fields, i.e., 120 T and 250 T when B is perpendicular and parallel to the CuO₂ planes, respectively. In addition to being sensitive to the stoichiometry of oxygen, the properties of YBCO are influenced by the crystallization methods applied. YBCO is a crystalline material, and the best superconductive properties are obtained when crystal grain boundaries are aligned by careful control of annealing and quenching temperature rates. However, these alternative methods still require careful sintering to produce a quality product. New possibilities have arisen since the discovery of trifluoroacetic acid, a source of fluorine that prevents the formation of undesired barium carbonate (BaCO₃). This route lowers the temperature necessary to obtain the correct phase at around 700℃. This, together with the lack of dependence on vacuum, makes this method a very promising way to achieve a scalable YBCO bulk.

• Korean Journal of Materials Research
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• v.4 no.1
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• pp.37-43
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• 1994

Y-Ra-Cu-0 oxide superconductors were fabricated by the sinter-forging method to make the critical current density improve through controlling of microstructure and crystal texture. The grain alignment of oxide superconductor was formed by the sinter-forging process and it's c-axis orientation was parallel to the press direction.The orientation factor of texture increased with sinking temperature and pressure, and also grain alignment was improved by the addition of Ag. As for the sinterforged Y-Ba-Cu-O/Ag sample, the $T_c$(on-set) was not almost varied with the sinter-forging temperature, but $T_c\;^{zero}$ decreased more or less at high sinter-forging temperatures. In addition, it was observed that added-Ag was mainly distributed along the grain boundar~es in the (123) matrix, resulting in the densification of microstructure. From these results, i t was thought that the improvement of $J_c$ over 2000A/$\textrm{cm}^2$ was attributed to the texture, densification of microstructure, and (123) grain growth due to the Ag addition.