• Journal of Chest Surgery
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• v.46 no.5
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• pp.340-345
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• 2013

Background: This study aims to evaluate whether or not the method of right vertical axillary minithoracotomy (RVAM) is preferable to and as reliable as conventional sternotomy surgery, and also assesses its cosmetic results. Methods: Thirty-three patients (7 males, 26 females) with atrial septal defect were admitted to the Cardiovascular Surgery Clinic of Cukurova University from December 2005 until January 2010. The patients' ages ranged from 3 to 22. Patients who underwent vertical axillary minithracotomy were assigned to group I, and those undergoing conventional sternotomy, to group II. Group I and group II were compared with regard to the preoperative, perioperative and postoperative variables. Group I included 12 females and 4 males with an average age of $16.5{\pm}9.7$. Group II comprised 14 female and 3 male patients with an average age of $18.5{\pm}9.8$ showing similar features and pathologies. The cases were in Class I-II according to the New York Heart Association (NYHA) Classification, and patients with other cardiac and systemic problems were not included in the study. The ratio of the systemic blood flow to the pulmonary blood flow (Qp/Qs) was $1.8{\pm}0.2$. The average pulmonary artery pressure was $35{\pm}10$ mmHg. Following the diagnosis, performing elective surgery was planned. Results: No significant difference was detected in the average time of the patients' extraportal circulation, cross-clamp and surgery (p>0.05). In the early postoperative period of the cases, the duration of mechanical ventilator support, the drainage volume in the first 24 hours, and the hospitalization time in the intensive care unit were similar (p>0.05). Postoperative pains were evaluated together with narcotic analgesics taken intravenously or orally. While 7 cases (43.7%) in group I needed postoperative analgesics, 12 cases (70.6%) in group II needed them. No mortality or major morbidity has occurred in the patients. The incision style and sizes in all of the patients undergoing RVAM were preserved as they were at the beginning. Furthermore, the patients of group I were mobilized more quickly than the patients of group II. The patients of group I were quite pleased with the psychological and cosmetic results. No residual defects have been found in the early postoperative period and after the end of the follow-up periods. All of the patients achieved functional capacity per NYHA. No deformation of breast growth has been detected during 18 months of follow-up for the group I patients, who underwent RVAM. Conclusion: To conclude, the repair of atrial septal defect by RVAM, apart from the limited working zone for the surgeon in these pathologies as compared to sternotomymay be considered in terms of the outcomes, and early and late complications. And this has accounted for less need of analgesics and better cosmetic results in recent years.

• Journal of the Korean Magnetics Society
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• v.6 no.6
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• pp.397-404
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• 1996

The magnetic properties of $Ni_{1-x}Zn_{x}Fe_{2}O_{4}$ have been studied by X-ray diffractometry and $M\"{o}ssbauer$ Spectroscopy at room temperature. The X-ray diffraction study show that spinel structure is formed in all x, lattice constants linearly increased from $8.3111{$\AA$}~8.4184{$\AA$}({\pm}0.0003)$ with increasing x from 0 to 1, and oxygen parameter increase with increasing x. $M\"{o}ssbauer$ spectrum shows that $Ni_{1-x}Zn_{x}Fe_{2}O_{4}(x=0)$ has two antiparallel magnetic structure due to $Fe^{3+}$ octahedral site and $Fe^{3+}$ tetrahedral site. $Ni_{1-x}Zn_{x}Fe_{2}O_{4}$ with $0.2{\leq}x{\leq}0.6$ has magnetic structure of Yafet and Kittel, in particularly, specimen with x=0.6 shows relaxation effect. Specimen with $x{\geq}0.8$ show paramagnetic quadrupole splitting. The isomer shift is independent of x, but quadrupole splittings decrease with increasing x in the range of $0.8{\leq}x{\leq}1$, and nuclear magnetic fields decrease with in¬creasing x in the range of $0{\leq}x{\leq}0.6$. The magnetic properties of $Ni_{1-x}Zn_{x}Fe_{2}O_{4}$ change from ferrimagnetics to pararnagnetics with increasing x.

• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2452-2459
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• 2020

Neutron spectrum is essential to the safe operation of reactors. Traditional online neutron spectrum measurement methods still have room to improve accuracy for the application cases of wide energy range. From the application of artificial neural network (ANN) algorithm in spectrum unfolding, its accuracy is difficult to be improved for lacking of enough effective training data. In this paper, an adaptive deviation-resistant neutron spectrum unfolding method based on transfer learning was developed. The model of ANN was trained with thousands of neutron spectra generated with Monte Carlo transport calculation to construct a coarse-grained unfolded spectrum. In order to improve the accuracy of the unfolded spectrum, results of the previous ANN model combined with some specific eigenvalues of the current system were put into the dataset for training the deeper ANN model, and fine-grained unfolded spectrum could be achieved through the deeper ANN model. The method could realize accurate spectrum unfolding while maintaining universality, combined with detectors covering wide energy range, it could improve the accuracy of spectrum measurement methods for wide energy range. This method was verified with a fast neutron reactor BN-600. The mean square error (MSE), average relative deviation (ARD) and spectrum quality (Qs) were selected to evaluate the final results and they all demonstrated that the developed method was much more precise than traditional spectrum unfolding methods.

• Journal of the Korean Magnetics Society
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• v.10 no.5
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• pp.220-224
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• 2000

Ultra-fine $Co_{1+x}$F $e_{2-}$2x/ $Ti_{x}$ $O_4$ferrite powders have been prepared by the sol-gel method. The crystallographic and magnetic properties of the sample have been investigated by means of x-ray diffraction, Mossbauer spetroscopy and vibrating sample magnetometry. The formation of nano crystallized particles is confirmed. The x-ray diffractions of all samples with various compositions clearly indicate the presence of spinel structure. The Mossbauer spectra could be fitted as the superposition of two sextets due to F $e^{3+}$ A-site and B-site. The IS and QS values nearly constant with substituted Co-Ti contents, whereas $H_{hf}$ of B-site decreases with increasing Co-Ti substitution in $Co_{1+x}$F $e_{2-}$2x/ $Ti_{x}$ $O_4$. The magnetic behaviour of powders shows that the saturation magnetization and the coercivity decrease with increasing x in $Co_{1+x}$F $e_{2-}$2x/ $Ti_{x}$ $O_4$.$.X>.

• Journal of the Korean Magnetics Society
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• v.13 no.6
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• pp.231-236
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• 2003

The $Al_{0.2}$CoF $e_{1.8}$ $O_4$ferrite powders have been prepared by the sol-gel method. The crystallographic and magnetic properties of the sample depending on annealing temperature have been investigated by means of x-ray diffraction, FE SEM, Mossbauer spetroscopy and vibrating sample magnetometry. The x-ray diffractions of all samples annealing temperature above 873 K clearly indicate the presence of spinel structure, the lattice constant decrease from 8.425 $\AA$ at 873 K to 8.321 $\AA$ at 1073 K, whereas the particle size rapidly increase from about 39 nm at 673 K to about 108 nm at 1073 K. The Mossbauer spectra annealed above 873 K could be fitted as the superposition of two sextets due to F $e^{3+}$ at A-site and B-site. The isomer shift (IS) and quadruple splitting (QS) values nearly constant with annealing temperature, whereas magnetic hyperfine field ( $H_{hf}$) of A-site slowly in crease and that of B-site fastly increases with increasing annealing temperature. The magnetic behaviour of powders shows that the saturation magnetization increase from 0.7 emu/g at 473 K to 72.1 emu/g at 1073 K while the coercivity decrease from 0.951 kOe at 673 K to 0.374 kOe at 1073 K with increasing annealing temperature.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.123-123
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• 2000

선폭이 초미세화됨에 따라 게이트 전극에서의 공핍 현상 및 불순물 확산의 물제를 갖는 poly-Si 게이트를 대체할 전극 물질로 텅스텐(W)이 많이 연구되어 왔다. 반도체 소자의 배선물질로 일찍부터 사용되어온 텅스텐은 내화성 금속의 일종으로 용융점이 높고, 저항이 낮다. 그러나, 일반적으로 사용되고 있는 CVD에 의한 텅스텐의 증착은 반응가스(WF6)로부터 오는 불소(F)의 게이트 산화막내로의 확산으로 인해 MOS 소자가 크게 열화될수 있다. 본 연구에서는 W/TiN 이중 게이트 전극 구조를 갖는 MOS 캐패시터를 제작하여 전기적 특성을 살펴보았다. P-Type (100) Si위에 RTP를 이용, 85$0^{\circ}C$에서 110 의 열산화막을 성장 및 POA를 수행한 후, 반응성 스퍼터링법에 의해 상온, 6mTorr, N2/Ar=1/6 sccm, 100W 조건에서 TiN 박막을 150, 300, 500 의 3그룹으로 증착하였다. 그 위에 LPCVD 방법으로 35$0^{\circ}C$, 0.7Torr, WF6/SiH4/H2=5/5~10/500sccm 조건에서 2000~3000 의 텅스텐을 증착하였다. Photolithography 공정 및 습식 에칭을 통해 200$\mu\textrm{m}$$\times$200$\mu\textrm{m}$ 크기의 W/TiN 복층 게이트 MOSC를 제작하였다. W/TiN 복측 게이트 소자와 비교분석하기 위해 같은 조건의 산화막을 이용한 알루미늄(Al) 게이트, 텅스텐 게이트 MOSC를 제작하였다. 35$0^{\circ}C$에서 증착된 텅스텐 박막은 10~11$\Omega$/ 의 면저항을 가졌고 미소한 W(110) peak값을 나타내는 것으로 보아 비정질 상태에 가까웠다. TiN 박막의 경우 120~130$\Omega$/ 의 면저항을 가졌고 TiN (200)의 peak 값이 크게 나타난 반면, TiN(111) peak가 미소하게 나타났다. TiN 박막의 두께와 WF/SiH4의 가스비를 변화시켜가며 제작된 MOS 캐패시터를 HF 및 QS C-V, I-V 그리고 FNT를 통한 전자주입 방법을 이용하여 TiN 박막의 불소에 대한 확산 방지막 역할을 살펴 보았다. W/TiN 게이트 MOS 소자는 모두 순수 텅스텐 게이트보다 우수하였고, Al 게이트와 유사한 전기적 특성을 보여주었다. W/TiN 게이트 MOS 소자는 모두 순수 텅스텐 게이트보다 우수하였고, Al 게이트와 유사한 전기적 특성을 보여주었다. TiN 박막이 300 , 500 이고 WF6/SiH4의 가스비가 5:10인 경우 소자 특성이 우수하였으나, 5:5의 경우에는 FNT 전자주입 특성이 열화되기 시작하였다. 그리고, TiN박막의 두께가 150 으로 얇아질 경우에는 WF6/SiH4의 가스비가 5:10인 경우에서도 소자 특성이 열화되기 시작하였다. W/TiN 복층 게이트 MOS 캐패시터를 제작하여 전기적인 특성 분석결과, 순수 텅스텐 게이트 소자의 큰 저전계 누설 전류 특성을 해결할 수 있었으며, 불소확산에 영향을 주는 조건이 WF6/SiH4의 가스비에 크게 의존됨을 알 수 있었다. TiN 박막의 증착 공정이 최적화 될 경우, 0.1$\mu\textrm{m}$이하의 초미세소자용 게이트 전극으로서 텅스텐의 사용이 가능할 것으로 보여진다.

• Journal of Wetlands Research
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• v.8 no.3
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• pp.67-77
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• 2006

Sedimentological investigations on surface and suspended sediments were performed in Masan Bay of the South Sea in order to reveal recent changes in depositional environments concerning anthropogenic influence. Surface sediments had been classified as 3 sediment facies: mud, slightly gravelly mud, and gravelly mud. In general, mud facies with more than 60% of silt is predominant and slightly gravelly mud facies occurs at the watercourse of bay's central area. The silt-dominant mud faices appears to be predominant before and after dredging. Temperature and salinity changes during one tidal cycle for each season suggest that water columns were stratified without vertical mixing regardless of the season due to weak intensity of tide from the effect of geographical features. The effect of freshwater discharge from the land seems to be insignificant. The strongest current was observed during ebb tide in spring and autumn while observed during flood tide in summer and winter. Net sediment flux (fs) and net suspended sediment transport (Qs) for suspended sediment were determined by remaining drift developed here. Net suspended sediment transport loads were seaward with $62.02{\times}10^3kgm^{-1}$, $31.84{\times}10^3kgm^{-1}$ in spring and fall, respectively, and landward with $18.23{\times}10^3kgm^{-1}$, $3.22{\times}10^3kgm^{-1}$ in summer and winter, respectively.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.967-975
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• 2022

Kombucha mutualistic community (KMC) is composed by acetic acid bacteria and yeasts, producing fermented tea with health benefits. As part of the BIOlogy and Mars EXperiment (BIOMEX) project, the effect of Mars-like conditions on the KMC was analyzed. Here, we analyzed metagenome-assembled genomes (MAGs) of the Komagataeibacter, which is a predominant genus in KMC, to understand their roles in the KMC after exposure to Mars-like conditions (outside the International Space Station) based on functional genetic elements. We constructed three MAGs: K. hansenii, K. rhaeticus, and K. oboediens. Our results showed that (i) K. oboediens MAG functionally more complex than K. hansenii, (ii) K. hansenii is a keystone in KMCs with specific functional features to tolerate extreme stress, and (iii) genes related to the PPDK, betaine biosynthesis, polyamines biosynthesis, sulfate-sulfur assimilation pathway as well as type II toxin-antitoxin (TA) system, quorum sensing (QS) system, and cellulose production could play important roles in the resilience of KMC after exposure to Mars-like stress. Our findings show the potential mechanisms through which Komagataeibacter tolerates the extraterrestrial stress and will help to understand minimal microbial composition of KMC for space travelers.

• Journal of Christian Education in Korea
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• v.76
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• pp.51-71
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• 2023

Purpose of study: Recognizing the importance of securing professionalism in church education in the context of the serious problem of church eucation in the Korean church today, this study aims to reveal the problems of current church education and suggest alternatives for solving the problems. Research content and method: The Korean church is facing crises. One of the crises is the decline in church membership and worship attendance. Another, more fundamental problem is the crisis of church education, where the number of students in Sunday schools is plummeting, and many young people are leaving the church. Many of them are questioning the quality of church education leaders. The decline and demise of Sunday schools does not bode well for the future of the Korean church. What the church needs to do to address these issues is to build up educational professionals. Leadership and professionalism are critical issues. Until now, the needs of church education in the Korean church have relied on dedication and life mission rather than professionalism. And these criteria were enough. It has been 34 years since the October 1989 resolution of the General Assembly of the Christian Church in Korea to establish a system of educators. However, little progress has been made and the system has not been changed to a system of educators. One of the ways to solve this problem is for the Korean church to prepare for the future of the Korean church by utilizing educators for church growth and the restoration of Sunday schools. Conclusions and Suggestions: For the function, mission, and purpose of the church, the system of educators is requested to be established in the Korean church as soon as possible to fulfill the professional church education and educational pastoral mission. In response to this call, current Korean church education needs to change and innovate. The direction of innovation is professional education, which means that there is a need and urgency for professional educators qs church education leaders.

• Clinical and Experimental Pediatrics
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• v.52 no.4
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• pp.494-498
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• 2009

Purpose : Applicability of transcatheter closure of atrial septal defect (ASD) has been expanded by accumulation of clinical experiences and evolutions of the device. This study was performed to evaluate the safety and efficacy of transcatheter closure of ASD with Amplatzer septal occluder (ASO) in young children less than 3 years of age. Methods : From May 2003 to December 2005, 295 patients underwent transcatheter closure of ASD with ASO in the Severance Cardiovascular Hospital, Yonsei University Health System. Among them, 51 patients less than 3 years of age were enrolled in this study. We investigated procedural success rate, rate of residual shunt, frequency of complications, procedure/fluoroscopy time, and need of modified techniques for device implantation. Results : The median age was 2.1 years and median body weight was 12 kg. Implantation of device was successful in 50 patients (98%). Seven patients (15%) showed a small residual shunt 1 day after the procedure, but complete occlusion had been documented at 6 month follow-up in all patients (100%). The pulmonary to systemic flow ratio (Qp/Qs), peak systolic pulmonary artery pressure, and peak systolic right ventricular pressure had decreased significantly after closure of ASD. There were 2 complications including device embolization (1, 2%) and temporary groin hematoma (1, 2%). Conclusion : Transcatheter closure of ASD with ASO can be performed with satisfactory results and acceptable risk even in young children less than 3 years of age. We could suggest that even in very young children with ASD, there is no need to wait until they grow to a sufficient size for the transcatheter closure.