• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.184-184
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• 2011

반도체 전자 소자의 초고집적회로(VLSI, Very Large Scale Integrated Circuit)가 수년간 지속됨에 따라 실리콘 기반으로 하는 MOSFET 성능의 한계에 도달하게 되었다. 재료 물성, 축소, 소자 공정 등에 대한 원인으로 이를 극복하고자 하는 재료와 성능향상에 관한 연구가 진행되고 있다. 이에 기존 시스템의 전자의 전하 정보만을 응용하는 것이 아니라 전자의 스핀 정보까지 고려하는 스핀트로닉스 연구분야가 주목을 받고 있다. Spin-FET는 스핀 주입, 스핀 조절, 스핀측정 등으로 나뉘어 연구되고 있으며 이 중 스핀 주입의 효율 향상이 우선시 해결되어야 한다. 일반적으로 스핀 주입 과정에서 소스가 되는 강자성체와 스핀 확산 거리가 긴 반도체 물질과의 Conductance mismatch가 문제되고 있다. 이에 자성 반도체는 근본적인 문제를 해결하고 반도체와 자성체의 특성을 동시에 나타내는 물질로써, Si과 Ge (4족) 등의 반도체뿐만 아니라, GaAs, InP (3-5족), ZnO, ZnTe (2-6족) 등의 반도체 또한 많은 연구가 이루어지고 있다. 자성 반도체에서 해결해야 할 가장 큰 문제는 물질이 자성을 잃는 Curie 온도를 상온 이상으로 높이는 것이다. 이에 본 연구는 전이금속이 도핑된 4족 Si 반도체 박막을 성장하고 후처리 공정을 통하여 나타나는 구조적, 자기적 특성을 연구하였다. 펄스 레이저 증착 방법을 통하여 p-type Si 기판위에 전이금속 Fe이 도핑된 박막을 500 nm 로 성장하였다. 성장 온도는 $250^{\circ}C$로 하였고, 성장 분압은 $3 {\times}10^{-3}$Torr 로 유지하며 $N_2$ 가스를 사용하였다. 구조적 결과를 보기 위해 X선 회절 분석과 원자력 현미경 결과를 확인하였고, 자기적 특성을 확인하기 위해 저온에서 초전도 양자 간섭계로 조사하였다. XRD를 통해 (002)면, (004)면의 Si 기판 결정을 보았으며, Fe 관련된 이차상이 형성됨을 예측해 보았다. ($Fe_3Si$, $Fe_2Si$ 등) 초전도 양자 간섭계에서 20 K에서 측정한 이력 현상을 관찰하고, 온도변화에 따른 전체 자기모멘트를 관찰하였으며 이는 상온에서도 강자성 특성이 나타남을 확인하였다.

• Resources Recycling
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• v.13 no.5
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• pp.28-36
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• 2004

The extraction of platinum group metals such as Pt, Pd and Rh from spent automobile catalyst has been investigated by leaching in HCl solutions using $HNO_3$ or NaOCl as a oxidant. The effect of type and amount of oxidant, reaction time and pulp density on the extraction of platinum group metals was examined. Platinum group metals were recovered by the cementation method using aluminum as a reducing agent. The extraction ratio was higher when NaOCl was used as a oxidant. The optimum leaching conditions were obtained to be: HCl 8 M, the amount of NaOCl 1.4 mole, leaching temperature $90^{\circ}C$, leaching time 180 minutes, pulp density 400g/L. Under the optimum conditions, the extraction of Pt, Pd and Rh were 96.1%, 93.6% and 77.3%, respectively. With the addition of 2.0g of aluminum which corresponds to 28 equivalent the reduction were 98% for Pt. 98.8% for Pd and 65.3% for Rh, respectively.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.192-192
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• 1994

본 논문에서는 cytochrome P450 LA1 유전자의 5'-upsteam 조절부위의 클로닝을 실시하였다. pUC19 vector에 연결시킨 3.4 Kb 크기의 Pstl DNA조각을 Sst1, Nco1 제한 효소로 자른 뒤, Exonuclease III 를 처리하여 약 200bp 씩의 차이를 갖는 여러 크기의 plasmid들을 얻었다. 이 plasmid 의 핵산서열을 알아보기 위해 dideoxy nucletide를 이용한 sequencing방법으로 그 핵산서열의 결정 실험을 시도하였다. 또한, 다환상 방향족 탄화수소 화합물에 반응성을 갖는 C57BL/6N 생쥐와 반응성을 갖지않는 DBA/2N 생쥐에 있어 phase II 대사 효소인UDP-glucuronosyltransferase 효소활성에 대한 3-methylcholanthrene의 영향을 알아보기 위해 C57BL/6N 생쥐와 DBA/2N 생쥐에 각각 다른 농도의 3-methylcholanthrene을 처리하거나 각기 다른 시간에 3-methylcholanthrene를 처리하였다. 그 결과 UDP-glucuronosyl-transferase의 mRNA가 3-methylcholanthrene양의 증가에 따라, 처치시간이 길어짐에 따라 증가되어지며 그 mRNA위 크기는 약 2.2Kb 정도임을 알았다. 이로부터 UDP-ghucuronosyltransferase 또한 cytochrome P45O와 함께 다환상 방향족 탄화수소 화합물 조절인자를 통한 조절을 받을 것이며 phase I phase II 약물 대사 효소가 조절상 밀접한 관련을 가짐을 예측할 수 있었다.

• Journal of Korean Foot and Ankle Society
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• v.10 no.2
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• pp.207-212
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• 2006

Purpose: To evaluate the results of ankle lateral malleolar fractures classified as Danis-Weber type B accompanying osteoporosis that were treated with lag screw. Materials and Methods: 15 cases of Danis-Weber type B ankle lateral malleolar fractures that had T score of less than -2.5 in BMD(bone mineral density) test were selected from June 2003 to December 2005. 10 cases were males and 5 cases were females with mean age of 59 years. The main injury mechanism was supination and external rotation. Mean follow-up period was 16 months. Clinical and radiologic evaluation was done according to Meyer and Kumler's criteria. Results: All cases showed satisfying result and mean radiologic bone union period was 3 months. Anatomic reduction and bone union was acquired in all cases without complications including wound infection, skin necrosis, delayed union and nonunion Conclusions: Lag screw fixation seem to be excellent treatment of Danis-Weber type B lateral malleolar fractures with osteoporosis as it can minimize soft tissue injury and enable anatomic reduction with firm fixation.

• Journal of the Korean Chemical Society
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• v.34 no.3
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• pp.248-254
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• 1990

Theoretical studies on the electrophilic substitution reactions of five-membered heteroaromatic compounds, furan, pyrrole and thiophene, with isopropyl cation were carried out using the MNDO method. The results indicated that site selectivities of ${\alpha},{\beta}$ and hetero-atoms are not controlled by electrostatic interactions but are determined mainly by charge trasfer stabilization between the HOMO of heteroaromatics and the LUMO of the electrophile. The reactivity order for ${\alpha}\;and\;{\beta}$ positions was pyrrole > furan > thiophene, in agreement with the solution-phase as well as the gas-phase experimental results.

• Journal of Life Science
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• v.30 no.10
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• pp.919-929
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• 2020

Aromatic compounds are widely used in the chemical, food, polymer, cosmetic, and pharmaceutical industries and are produced by mainly chemical synthesis using benzene, toluene, and xylene or by plant extraction methods. Due to many rising threats, including the depletion of fossil fuels, global warming, the strengthening of international environmental regulations, and the excessive harvesting of plant resources, the microbial production of aromatic compounds using renewable biomass is regarded as a promising alternative. By integrating metabolic engineering with synthetic and systems biology, artificial biosynthetic pathways have been reconstituted from L-tryptophan biosynthetic pathway in relevant microorganisms, such as Escherichia coli and Corynebacterium glutamicum, enabling the production of a variety of value-added aromatic compounds, such as 5-hydroxytryptophan, serotonin, melatonin, 7-chloro-L-tryptophan, 7-bromo-L-tryptophan, indigo, indirubin, indole-3-acetic acid, violacein, and dexoyviolacein. In this review, we summarize the characteristics, usage, and biosynthetic pathways of these aromatic compounds and highlight the latest metabolic engineering strategies for the microbial production of aromatic compounds and suitable solution strategies to overcome problems in increasing production titers. It is expected that strain development based on systems metabolic engineering and the optimization of media and bioprocesses using renewable biomass will enable the development of commercially viable technologies for the microbial production of many aromatic compounds.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.399-408
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• 2018

The purpose of this study is to investigate the effects of father's family-of-origin experiences on parenting attitude and parenting participation around mediating effects of value of children. To this end, this study investigated family-of-origin experience, value of children, parenting attitude, and degree of parenting participation on 247 fathers of 3~5 year old children. Descriptive statistics, correlation analysis, regression analysis, and Sobel Test were conducted using SPSS 21 program on the collected data. According to the research result, there was a significantly positive relationship between emotional value of children, parenting attitude, and parenting participation among family-of-origin experience and value of children. This study conducted a regression analysis and Sobel Test by stage to identify mediating effects. As a result, it was identified that father's family-of-origin experience makes positive effect on parenting attitude and parenting participation, and emotional value of children among value of children mediates their relationship. Based on the findings, this study suggested that multilateral consideration and systematic system for formation of positive value of children are needed and suggested the direction of follow-up study on fathers as a coparent.

• Journal of Korean Foot and Ankle Society
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• v.4 no.2
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• pp.55-60
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• 2000

Purpose: To investigate the effect of heel elevation on the radiographic parameters of the forefoot. Materials and Methods: Forty feet in twenty-one adults were studied. Weight bearing dorsoplantar radiograph was taken with the foot on a flat surface and with the heel of the foot elevated by 5cm. Various parameters were measured and compared between the results with and without heel elevation. Result: The hallux valgus angle was increased by $5.0{\pm}3.5$ degrees with heel elevation and the change was statistically significant(p<0.01). There was no statistically significant changes in the other parameters. Conclusion: The results of this study suggest that high-heeled shoes might contribute in causing or aggravating the degrees of the hallux valgus.

• The Journal of the Korean bone and joint tumor society
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• v.14 no.1
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• pp.33-43
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• 2008

Purpose: To evaluate the clinical usability of reconstructive methods, and how to select flap after wide excision of malignant soft tissue tumor in ankle and foot. Materials and Methods: The 15 cases shown in the 14 patients (In case of a male patient, reconstruction was performed two times due to local recurrence.) with malignant soft tissue tumor in ankle and foot, who underwent reconstruction after wide excision from March 2000 until March 2007. Oncologic, surgical and functional results were evaluated. Results: The method of reconstruction used were anterolateral thigh perforator flap (5cases), Reversed superficial sural artery flap (4 cases), dorsalis pedis flap (3 cases), local flap (3cases). The defect, mean size was $5.5{\times}5.7\;cm$, was reconstructed with rotation flap or free flap, mean size was $5.9{\times}6.0\;cm$, skin graft for remnant. The mean operation time was 310 minutes (120~540 minutes); it took 256 minutes to reconstruct by rotation flap, and 420 minutes by free flap. As oncologic results, 7 patients were no evidence of disease, 6 patients were alive with disease and 1 patient was expired by pulmonary metastasis at the time of the last follow-up. 4 patients had local recurrence and 4 pateints had distant metastases. As functional results, 14 patients were evaluated with average score of 68.8% using the system of the Musculoskeletal Tumor Society. Conclusion: The dorsalis pedis and reverse superficial sural artery rotation flap which is easy procedure, has less complication and takes short operation time, can be primarily considered to reconstruct a small defect. And the anterolateral thigh perforator flap is suitable for coverage of a large defects after wide excision of malignant soft tissue tumor in ankle and foot.

• Resources Recycling
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• v.28 no.2
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• pp.46-53
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• 2019

In this study, the extraction and reduction behavior of platinum group metals in a non-aqueous solvent based on ionic liquids was investigated in order to confirm a new extraction technology of platinum group metals. Platinum was selectively extracted using an ionic liquid $[C_4mim]PF_6$ from a mixed solution of $PdCl_2$, $PtCl_4$ and $RhCl_3$ dissolved with concentration ratio of 10:1:0.5 M. After stripping of the metals by 1 M $HNO_3$ solution, the platinum was preferentially reduced by aqueous electrolysis on gold electrode at -0.8 V (vs. Pt-QRE). The residual palladium and rhodium were transferred to ionic liquid of $[C_4mim]Cl$. The metallic palladium and rhodium could be sequentially reduced on gold and STS304 as working electrodes by non-aqueous electrolysis, respectively.