외부전계 인가에 의한 조화용융조성 LiNbO₃ 결정의 주기적 분극반전

권순우,양우석,이형만,김우경,이한영,윤대호,송요승,Kwon, Soon-Woo,Yang, Woo-Seok,Lee, Hyung-Man,Kim, Woo-Kyung,Lee, Han-Young,Yoon, Dae-Ho,Song, Yo-Seung 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.11

When an electric field higher than a characteristic coercive field is applied to a ferroelectric such as $LiNbO_3$, the orientation of the spontaneous polarization is reversed, which causes the reversal of the sign of odd-rank tensor properties such as electro-optic and nonlinear optic coefficients. A fabrication process of insulator and periodic external field assisted poling of a z-cut $LiNbO_3$ have been optimized for a periodic $180^{\circ}$ phase inversion along z-axis. The poling jig and the poling control system, fully controlled by a computer, for high quality and reproducible PPLN fabrication have been devised. Periodically polarization reversed PPLN was adjusted based on the fabricated thickness of insulator. The poling structure of PPLN was observed under a microscope after etching PPLN samples by an etching solution ($HF:HNO_3$ = 1 : 2) for about 15 min.

Diversity and Phylogenetic Analysis of Fluorescent Pseudomonads Isolated from Soil-Root System of Red Pepper in Greenhouse

권순우,김종식,송재경,류진창,Kwon, Soon-Wo,Kim, Jong-Shik,Song, Jae-Kyeong,Ryu, Jin-Chang 한국토양비료학회 2000 한국토양비료학회지 Vol.33 No.4

고추 시설 재배지 토양, 근권과 근면등으로부터 형광성 pseudomonads를 분리한 후 이들 중 35균주에 대해 계통 분석을 실시하였다. 계통 분석에 이용된 분류키는 165 rDNA의 일부 염기서열로, 종 수준에서 분류동정을 실시하였다. 고추재배지로부터 분리된 형광성 pseudomonads중 P. putida group으로 분류된 균주는 17균주 였으며, 이들은 주로 비근권 토양으로부터 분리되었다. 이들은 4개의 소그룹 (subgroup I, II, III, IV)으로 분류되었으며, 소그룹 I, IV에 속한 균주는 P putida의 표준균주가 속한 소그룹 II, III의 균주와는 분류학적으로 뚜렸히 구분되는 독특한 균주들이었다. P. fluorescens로 분류된 균주는 15균주였으며, 나머지 3균주는 P. fluorescens와 P. chloraphis의 중간 그룹으로 분류되었다. 근권으로부터 분리된 균주는 대부분 P. fluorescns로 분류되었으며, 이들의 유전적 유연관계는 매우 높게 나타났다. 본보의 결과에 비추어 볼 때, 고추의 근계는 P. fluorescens의 특정 균주에 의해 정착되는 것으로 생각되었다. Among the fluorescent pseudomonad isolates from soil- root system of red pepper in Chinju, Kyunsangnam-Do, the phylogenetic analysis for 35 isolates were conducted. The partial 16S ribosomal DNA sequences were used as taxonomic key for phylogenetic analyses, and these sequences were enabled to identification of the fluorescent pseudomonad isolates on the species level. The 17 isolates among them were classified into Pseudomonas putida group, and consisted of the strains isolated mainly from soil. This group were subdivided into 4 subgroups (I, II, III, and IV). The subgroup I and IV were unique ones which were relatively remotely related with subgroup II and III including the type strain of P. putida. The 15 isolates among 35 isolates were grouped along with the type strain of Pseudomonas fluorescens, and 3 isolate were characterized as intermediates of P. fluorescens and Pseudomonas chlororaphis. Most of strain isolateds from the rhizosphere soil and rhizoplane of red pepper were identified as P. fluorescens and closely related with each other. In this study, root of red pepper was supposed to be colonized by a specific strain or strains of P. fluorescens.

조화용융조성 $LiNbO_3$의 주기적 분극 반전 동안 도메인 생성 및 이동에 관한 연구

권순우,양우석,이형만,김우경,이한영,윤대호,송요승,Kwon, S.W.,Yang, W.S.,Lee, H.M.,Kim, W.K.,Lee, H.Y.,Yoon, D.H.,Song, Y.S. 한국결정성장학회 2006 한국결정성장학회지 Vol.16 No.2

조화용융조성 $LiNbO_3$ 결정에 외부 전계를 인가하였을 때 초기 도메인 생성 및 이동에 관하여 연구하였다. 0.5mm 두께의 $LiNbO_3$ 결정에 23.5, 22.0, 21.0kV/mm의 전계를 인가하였을 때 도메인 벽은 각각 28.70, 16.02, $5.75{\mu}m/sec$의 속도를 나타내었다. 분극 반전 시스템에 전류 제어를 위한 외부저항으로 $1 M{\Omega}$을 사용하였을 시 너무 빠른 도메인 성장으로 인하여 원활한 분극 반전 제어가 이루어지지 않으므로 $10 M{\Omega}$ 외부저항을 사용하여 전하량을 제어하여 50% duty cycle을 가진 주기적 분극 반전 $LiNbO_3$ 결정을 제작하였다. When external field was applied to congruent $LiNbO_3$, it was investgated for domain formation and expansion of $LiNbO_3$. The domain wall velocities of 0.5 mm thickness $LiNbO_3$ were 28.70, 16.02 and $5.75{\mu}m/sec$ under poling field of 23.5, 22.0 and 21.0 kV/mm, respectively. As $1 M{\Omega}$ resistor was used in domain inversion system, harmonic domain inversion was not achieved by rapid domain expansion. And 50% duty cycle periodically poled $LiNbO_3$ have been fabricated by charge control using $10 M{\Omega}$ resistor.

Phylogenetic analysis of the genera Azorhizobium, Bradyrhizobium, Mesorhizobium, Rhizobum and Sinorhizobium on the basis of internally transcribed spacer region

권순우,김창영,류진창,고승주,Kwon, Soon-Wo,Kim, Chang-Yung,Ryu, Jin-Chang,Go, Seung-Joo Korean Society of Soil Science and Fertilizer 2002 한국토양비료학회지 Vol.35 No.1

근류형성에 의한 생물학적 질소고정기능을 갖는 여러종의 근류균을 대상으로 분자생물학적 계통 분류의 기초자료를 얻기 위하여 Azorhizobium, Bradyrhizobium, Mesorhizobium, Rhizobium, Sinorhizobium 속의 33 균주에 대한 ITS 영역의 염기서열을 이용한 계통 분류가 이루어 졌다. 이들 균주중 대부분의 균주는 한 종류의 ITS 영역을 가지는 반면, 일부균주는 2개의 서로 다른 ITS 염기서열을 가지는 것으로 나타났다. 실험에 이용된 모든 균주들간의 ITS 영역의 염기서열 상동성은 28 - 95%로 매우 변이폭가 컸으며, 이들 염기서열의 계통 분석에 의하면 4가지 그룹으로 구분되었다. Sinorhizobium 속의 모든 균주 및 Rhizobium giardinii 는 그룹 I으로 구분되었다 그룹 II는 R. giardinii를 제외한 모든 Rhizibium 속의 균주를 포함하고 있으며, 계통수의 topology는 매우 불안정한 것으로 나타났다. 특히, R. radiobacter와 R. rubi는 계통분류학적 위치가 불명확한 것으로 나타났다. Bradyrhizobium 속의 균주는 Azorhizobium caulinodans 와 함께 그룹 III로 구분되었고, 그룹 IV는 Mesorhizobium 속의 균주로 이루어 ㅈ다. 특히, Mesorhizobium 속균주의 ITS 영역의 염기서열 상동성이 높게 나타났다. The phylogenetic relationships for 33 strains belonging to the genera Azorhizobium, Bradyrhizobium, Mesorhizobium, Rhizobium and Sinorhizobium were conducted by the sequence analyses of the ITS regions. The sequence homologies of these strains showed the high variations(28.0 - 94.9%). According to the phylogenetic analysis of ITS regions. 37 ITS clones from 33 strains of 32 species were classified into four groups. Group I included all strains of the genus Sinorhizobium as core members and R. giardinii as a peripheral member. The genus Rhizobium strains were clustered into group II which was very heterogeneous and the tree toplogy of this group were very unstable. Among the members of group II. the taxonomic position of R. radiobacter and R. rubi was not clearly identified on the basis of ITS I regions. R. undicola and R. vitis were remotely related with other Rhizobium strains including R. leguminosarum, R. galegae, R. gallicum, R. mongolense, R. tropici, R. hainanense, R. rhizogense and R. huautlense of group II were supposed to be loosely related to R. leguminosarum. While the stains of the genera Bradyrhizobium constituted group III with Azorhizobium caulindans, the strains of the genus Mesorhizobium formed group IV on the relatively high sequence homology level.

화학반응을 고려한 스토커식 소각로의 3차원 모사연구

권순우 ( Soon Woo Kwon ),이종협 ( Jong Heop Yi ) 한국화학공학회 1998 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.36 No.3

아크릴레이트 계 UV차단 코팅막의 물성에 관한 연구

권순우(Soonwoo Kwon),김병준(Byungjoon Kim),노혜란(Hyeran Noh) 한국고분자학회 2017 폴리머 Vol.41 No.2

스핀코팅 시 액체의 유변학적 성질을 고려하여 다관능 아크릴레이트 기반의 광학용 자외선 차단 코팅을 개발하였다. 스핀코팅 시 변수들(회전속도, 고정 회전속도 도달시간, 가교시간)에 따른 코팅막의 광 차단율, 코팅 두께 그리고 코팅의 신뢰성을 평가하였다. 그 결과 우레탄 올리고머 추가 없이 다관능의 아크릴레이트 단량체의 조합으로 UV 차단율이 68%(UV-A와 UV-B) 이상 가능하고 가시광선 투과율이 95% 이상인 광학용으로 적합한 광 차단코팅을 제조하였다. 스핀코터의 회전 속도와 최고 회전속도 도달 시간이 증가함에 따라 코팅 박막의 두께와 자외선 차단율이 증가하는 추세를 보였다. 본 연구에서는 실험과 이론으로 스핀코팅 공정과정을 분석하였으며 그 결과 우수한 광학 특성, 내마모성, 내화학성을 지니는 UV차단 코팅막을 개발하였다. Acrylate based UV protective coating was developed with understanding of rheological properties of polymer fluid. Depending on variables (a rotating speed, ramping time to reach the fixed speed, and crosslinking time), we evaluated physical properties such as film thickness, light blocking rate, and reliability. As a result, thin optical transparent film with UV blocking rate of 68% (total of UV-A and UV-B) and visible light transmittance of more than 95% was developed with acrylate based polymer film excluding urethane oligomers. With increasing rotating speed and ramping time to reach the fixed rotating speed, thickness and the light blocking rate of film was increased. In conclusion, we examined the spin coating process both experimentally and fundamentally with acrylate based UV protective coating. The developed UV protective film showed good optical properties in addition to satisfactory wear and chemical resistances.

청각장애 학생의 어휘력 향상을 위한 교수-학습 전략 탐색

권순우(Soon-Woo Kwon) 한국언어치료학회 2004 言語治療硏究 Vol.13 No.4

The purpose of this study is to offer basic data which benefit students with hearing impairment to elevate vocabulary ability, by rethinking direction for their language instruction through finding out various learning methods which helped them acquire present vocabulary ability and analyzing it. The subject was selected 3 students with hearing impairment who attend C., D., N., university. The teaching and learning strategies for improving their vocabulary ability drawn from this study are as follows; First, it should be focus various language knowledge upon making a system organically. Second, it should be put on relative importance at reading guidance. Third, it should be make longer real experience opportunity. Fourth, it should be developed materials as active-opened attitude. Fifth, it should be done language education as trait of students with hearing impairment.

청각장애 학교교육과정 실행 결과의 평가

권순우(Soon-Woo Kwon) 한국언어치료학회 2005 言語治療硏究 Vol.14 No.3

The study is to find out what are educational outcomes, after applying programs developed for restructuring school curriculum of deaf school. The educational outcomes are as follows; ① maintenance of the bright face and establishment of self-identification, ② philosophical reformation in school based curriculum for the deaf, increase of competencies, ③ increase of the literacy ability, ④ increase of the intimate spirits in environments for the deaf as ecological approach and making togetherness of peer group. ⑤ assimilation of the teaching experiences of the senior teachers for the deaf.The demerits of the educational outcomes which mean problems for guarantee the effective school curriculum are as follows; ① difficulties in teaching between beginning teachers and skilled teachers ② difficulties in decreasing of the teaching hours, payment of the teaching allowance both the two teachers in cooperation teaching of the same class, ③ difficulties in managing teaching hours and managing teaching of teachers in subject-centered teachings, ④ have a crisis in self-esteem due to difficulties in expressing their manpower.

참관실습에서 나타나는 예비특수교사의 장애학생에 대한 인식 및 관계 변화에 대한 질적 연구

권순우 ( Soon Woo Kwon ),정병종 ( Byung Jong Jeong ) 한국정서.행동장애아교육학회(구.한국정서학습장애아교육학회) 2010 정서ㆍ행동장애연구 Vol.26 No.4

본 연구는 참관실습이 예비특수교사들에게 특수교육에 관련된 다양한 문제인식을 변화시킬 수 있는 계기가 될 수 있는지 탐색해 보았으며, 질적 연구방법을 사용하였다. 연구 자료는 구조화된 질문지, 면담, 참관실습 일지를 통해 수집되었으며, 이외에도 여러 가지 문서들을 활용하였다. 본 연구는 예비특수교사들이 참관실습을 통해 장애학생에 대한 어떤 인식변화와 관계 변화를 겪게 되는지와 참관실습의 운영에 있어서 문제점과 개선 방안을 알아보았다. The purpose of this study was to investigate whether the field observation practice provides would-be special education teachers with a chance to change their awareness relating to special education. A qualitative research method was used for this study. Data was collected by a structured questionnaire, interviews, field observation practice journals, and other documents. The results of this study informed us what change of awareness about, and relationship with, students with special needs would-be special education teachers experience through the field observation practice. It also informed us problems in the process of the field observation practice and strategies to solve them.

Incoloy 909 합금의 최적 알루미나이징 확산 코팅

권순우(S.W. Kwon),윤재홍(J.H. Yoon),주윤곤(Y.K. Joo),조동율(T.Y. Cho),안진성(J.S. Ahn),박봉규(B.K. Park) 한국표면공학회 2007 한국표면공학회지 Vol.40 No.4

An Fe-Ni-Co based superalloy Incoloy 909 (Incoloy 909) has been used for gas turbine engine component material. This alloy is susceptible to high temperature oxidation and corrosion because of the absence of corrosion resistant Cr. For the improvement of durability of the component of Incoloy 909 aluminizing-chromate coating by pack cementation process has been investigated at relatively low temperature of about 550℃ to protect the surface microstructure and properties of lncoloy 909 substrate. As a previous study to aluminizing-chromate coating by pack cementation of Incoloy 909, the optimal aluminizing process has been investigated. The size effects of source AI powder and inert filler Al₂O₃ powder and activator selection have been studied. And the dependence of coating growth rate on aluminizing temperature and time has also been studied. The optimal aluminizing process for the coating growth rate is that the mixing ratio of source Al powder, activator NH₄Cl and filler Al₂O₃ are 80%, 1% and 19% respectively at aluminizing temperature 552℃ and time 20 hours.