고온초전도 직류 케이블용 절연재료인 PPLP의 직류 및 임펄스 절연 특성

김우진,방만식,김해종,조전욱,김상현,Kim, Woo-Jin,Pang, Man-Sik,Kim, Hae-Jong,Cho, Jeon-Wook,Kim, Sang-Hyun 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.7

To realize the high-Tc superconducting (HTS) DC cable system, it is important to study not only high current capacity and low loss of conductor but also optimum electrical insulation at cryogenic temperature. A model HTS DC cable system consists of a HTS conductor, semi-conductor, cooling system and insulating materials. Polypropylene laminated paper (PPLP) has been widely adopted as insulating material for HTS machines. However, the fundamental insulation characteristics of PPLP for the development of HTS DC cable have not been revealed satisfactorily until now. In this paper, we will discuss mainly on the breakdown characteristics of 3 sheets PPLP in liquid nitrogen ($LN_2$). The characteristics of the diameter, location of butt-gap, distance between butt-gap length, pressure effect, polarity effect under DC and impulse voltage were studied. Also, the DC polarity reversal breakdown voltage of mini-model cable was measured in $LN_2$ under 0.4 MPa.

황산화 배소법에 의한 구리성분의 선택적 침출연구

김우진,김준수,김명준,이진영,신선명,Kim, Woo Jin,Kim, Joon Soo,Kim, Myong Jun,Tran, Tam,Lee, Jin-Young,Shin, Shun-Myung 한국자원리싸이클링학회 2016 資源 리싸이클링 Vol.25 No.5

본 연구는 호주산 저품위 동광의 선광실험결과로 얻은 고품위 광물의 황산화 배소 및 선택적 침출반응 조건 확립을 통해 유가 광물 중에 함유된 성분을 선별적으로 용해해냄으로써 철 성분을 비롯한 불순물을 줄이거나, 동 및 니켈 성분을 용해 혹은 잔사에 잔류시킴으로써 유가금속회수를 효과적으로 회수하고자 하는데 목적이 있다. 본 연구실험결과 얻은 최적조건은 황산화 배소시 $450^{\circ}C$, $Na_2SO_4$ 2 mole ratio 및 1.5 h이었고, 배소산물의 침출온도는 상온 및 침출제는 $H_2O$ 혹은 1M $H_2SO_4$이었다. 최적조건 하에서 Cu 성분은 90 wt.% 침출율을 Fe성분은 20 wt.%내외, Ni성분은 15 wt.% 정도를 나타내는 것으로 보아 선택적 분해침출이 가능하다. This study were carried out sulfation roasting and selective leaching test for the effective recovery of copper component in concentrate obtained by froth floatation of Autrallian low grade copper ore. The optimum conditions of sulfation roasting were temp. $450^{\circ}C$, $Na_2SO_4$ 2 mole ratio and time 1.5 h, and then selective leaching were room temperature and $H_2O$ or 1M $H_2SO_4$ solutions. Leaching efficiency of optimum sulfation product were 90 wt.% of copper, 20 wt.% of iron and 15wt.% of nickel elements. In this results, it was possible to selective decomposition leaching of the copper component under optimum conditions in this research.

Genetic Relationships of Four Korean Oysters Based on RAPD and Nuclear rDNA ITS Sequence Analyses

김우진,이정호,김경길,김영옥,남보희,공희정,정현택,Kim, Woo-Jin,Lee, Jeong-Ho,Kim, Kyung-Kil,Kim, Young-Ok,Nam, Bo-Hye,Kong, Hee-Jeong,Jung, Hyung-Taek The Malacological Society of Korea 2009 The Korean Journal of Malacology Vol.25 No.1

Random amplified polymorphic DNA (RAPD) marker and sequence analyses of the internal transcribed spacer (ITS) region of ribosomal DNA were used to assess phylogenetic relationships of four Korean oyster species. The average number of species-specific markers identified from five universal rice primers (URPs) by RAPD-PCR was 1.8 for Crassostrea gigas, 3.2 for C. nippona, 3.6 for C. ariakensis, and 4.6 for Ostrea denselamellosa. The length of the ITS (ITS1-5.8S-ITS2) region ranged from 1,001 to 1,206 bp (ITS1, 426-518 bp; 5.8S, 157 bp; and ITS2, 418-536 bp), while the GC content ranged from 55.5-61.1% (ITS1, 56.8-61.8%; 5.8S, 56-57.3%; and ITS2, 54.1-62.2%). A phylogenetic analysis of the oysters based on our RAPD, ITS1, and ITS2 sequence data revealed a close relationship between C. gigas and C. nippona and a distant relationship between the genera Crassostrea and Ostrea. Our results indicated that RAPD and ITS sequence analysis was a useful tool for the elucidation of phylogenetic relationships and for the selection of species-specific markers in Korean oysters.

고도근시에서 시신경유두주위 위축 범위에 따른 빛간섭단층촬영의 녹내장 진단력 비교

김우진,김경남,김창식,Woo Jin Kim,Kyung Nam Kim,Chang Sik Kim 대한안과학회 2013 대한안과학회지 Vol.54 No.12

Purpose: To evaluate diagnostic power to detect glaucoma in high myopic eyes with peripapillary atrophy among optical coherence tomography (OCT) parameters. Methods: Fifty eyes of 31 glaucoma patients with myopia of -6.00 diopters or less and a peripapillary atrophy (PPA) were classified into a group with a PPA located beyond the circumpapillary OCT scan circle (group A) and a group with a PPA confined within the scan circle (group B). Circumpapillary retinal nerve fiber layer (cpRNFL), total macula (TM), and ganglion cell-inner plexiform layer (GCIPL) thickness were measured in each group and the diagnostic power of each measurement was compared by area under the receiver operating characteristic curve (AUC). Results: There were no significant differences in the age, gender, intraocular pressure, optic disc size, and mean deviation between the 2 groups. The spherical equivalent of group A was significantly larger than group B (mean -11.9 vs. -7.3 diopters, p = 0.002). In group A, the AUC of average GCIPL thickness was significantly higher than average cpRNFL and average TM thickness (p < 0.05). Additionally, when comparing parameters that showed the highest AUC value in each method, the AUC of GCIPL thickness was significantly higher than cpRNFL thickness (p = 0.046). In subgroup analysis of spherical equivalent matching between the 2 groups (subgroup A and B), the highest AUC value of GCIPL thickness was significantly higher than cpRNFL and TM thickness in subgroup A (p < 0.05). In group B and subgroup B, there was no statistical significance among AUC values of the 3 different methods (p > 0.05). Conclusions: Assessment of GCIPL parameters is a useful technique for glaucoma diagnosis in patients with high myopia and PPA extending beyond circumpapillary OCT scan circle. <br /> J Korean Ophthalmol Soc 2013;54(12):1844-1855

Ti 첨가강의 Ti와 C 함량에 따른 초기 오스테나이트 입도 변화

김우진,강남현,도형협,김성주,남대근,조경목,Kim, Woo-Jin,Kang, Nam-Hyun,Kim, Sung-Ju,Do, Hyung-Hyup,Nam, Dae-Geun,Cho, Kyung-Mox 한국재료학회 2011 한국재료학회지 Vol.21 No.4

Prior austenite grain size plays an important role in the production of high strength hot-rolled steel. This study investigated the effect of Ti and C contents on the precipitates and prior austenite grain size. Steel with no Ti solutes had prior austenite grain size of about 620 ${\mu}m$. The addition of Ti ~ 0.03 wt.% and 0.11 wt.% reduced the prior austenite grain size to 180 ${\mu}m$ and 120 ${\mu}m$, respectively. The amount of Ti required to significantly decrease the prior austenite grain size was in the range of 0.03 wt.%. However, the amount of carbon required to significantly decrease the prior austenite grain size was not present from 0.04 wt.% to 0.12 wt.%. Oxides of Ti ($Ti_2O_3$) were observed as the Ti content increased to 0.03 wt.%. The specimen containing 0.11 wt.% of Ti exhibited the complex carbides of (Ti, Nb) C. The formation of Ti precipitates was critical to reduce the prior austenite grain size. Furthermore, the consistency of prior austenite grain size increased as the carbon and Ti contents increased. During the reheating process of hot-rolled steel, the most critical factor for controlling the prior austenite grain size seems to be the presence of Ti precipitates.

2×2 서브블록에서 최소/최대값을 이용한 가역 정보은닉기법 연구

김우진,김평한,이준호,정기현,유기영,Kim, Woo-Jin,Kim, Pyung-Han,Lee, Joon-Ho,Jung, Ki-Hyun,Yoo, Kee-Young 대한전자공학회 2014 전자공학회논문지 Vol.51 No.4

본 논문에서는 하나의 서브블럭내에서 픽셀값정렬과 예측오차확장기법을 확장한 새로운 가역 정보은닉기법을 제안한다. 각 $2{\times}2$ 서브블록에서 최소값 그룹과 최대값 그룹으로 나누고, 최소값 그룹에서는 제일 작은 값에 비밀자료를 숨기고, 최대값 그룹에서는 제일 큰 값에 비밀자료를 숨긴다. 제안한 알고리즘은 평균 13,900 비트의 삽입용량을 가지는데 이 결과는 31.39dB의 시각적인 왜곡을 유지하면서 기존 알고리즘보다 4,553 비트 더 많이 숨길 수 있음을 실험을 통해서 보여주고 있다. A novel reversible data hiding method using pixel value ordering and prediction error expansion in the sub-block is resented in this paper. For each non-overlapping $2{\times}2$ sub-block, we divide into two groups. In the min group, the lowest value is changed to embed a secret bit and the highest value is changed in the max group. The experimental results show that the proposed method achieves a good visual quality and high capacity. The proposed method can embed 13,900 bits on average, it is higher 4,553 bits than the previous method and the visual quality is maintained 31.39dB on average.

난치성 신생혈관 녹내장에서 유리체강내 베바시주맙과 구후 트리암시놀론 동시 주사 효과

김우진,정진구,유인천,이동욱,Woo-Jin Kim,Jin-Gu Jeong,In-Cheon You,Dong-Wook Lee 대한안과학회 2010 대한안과학회지 Vol.51 No.4

Purpose: To identify the regression of neovascularization and relief of other symptoms after intravitreal bevacizumab and retrobulbar triamcinolone injection in neovascular glaucoma patients with no possibility of visual acuity recovery. Methods: A total of 15 eyes in 15 patients with neovascular glaucoma, who had no possibility of visual acuity recovery and could not be treated with surgical intervention despite pain from October 2008 to May 2009, were reviewed retrospectively. Changes in degree of pain, conjunctival injection, revascularization, and visual acuity were evaluated after injection. Results: Ten of the 15 (67%) neovascular glaucoma patients were male, with a mean age of 62.50±12.79 years. The most common prediposing ocular disease was diabetic retinopathy (9; 60%), and the others were central retinal vein occlusion (4: 26%), central retinal artery occlusion (1; 7%), and uveitis (1; 7%). Change in intraocular pressure was significant (p<0.001), as were decreases in the degrees of pain and conjunctival injection (p<0.001, <0.001) after the injections. Regression of neovascularization continued in 13 patients (87%) after two months. Conclusions: Intravitreal bevacizumab and retrobulbar triamcinolone injection is a safe intervention that can substantially relieve pain experienced by neovascular glaucoma patients. J Korean Ophthalmol Soc 2010;51(4):568-574

백내장 수술 후 발생한 안내염 환자에 관한 8년간의 고찰

김우진,권의용,이동욱,조남천,Woo Jin Kim,Eui Yong Kweon,Dong Wook Lee,Nam Chun Cho 대한안과학회 2008 대한안과학회지 Vol.49 No.11

Purpose: To estimate the annual incidence rate, evaluate any changes, analyze the microbiologic spectrum of infecting organisms, antibiotic susceptibility, and factors associated with visual outcomes of postoperative endophthalmitis following cataract surgery over an 8-year period. Methods: A retrospective investigation of direction, sex, age, culture results, interval duration, and initial visual acuity of 29 patients with endophthalmitis following cataract surgery was conducted from January 2000 to December 2007. The study was divided into two 4-year periods, with patients categorized into either Group 1 or 2. Results: The incidence rate was 0.359%, the major infective organism was Staphylococcus epidermidis, and no significant change was observed during the 8-year period. Vancomycin retained efficacy in all cases, but increased resistance occurred with ciprofloxacin during the 8 years. Increased visual acuity after treatment was greater in Group 2 and the interval from onset of ocular symptoms to ophthalmic consultation was shorter in Group 2, although a statistical significance was not demonstrated. Conclusions: Vancomycin remains effective for patients with endophthalmitis following cataract surgery. Patients who initially had good visual acuity showed greater improvement. However, sex, age, or whether or not the patients had a vitrectomy operation, were not statistically significant factors in the improvement of visual acuity. J Korean Ophthalmol Soc 2008;49(11):1771-1778

누소관 열상 환자에서 누소관 성형술의 해부학적 및 기능적 성공요인의 분석

김우진,안민.Woo Jin Kim. MD. Min Ahn. MD. PhD 대한안과학회 2011 대한안과학회지 Vol.52 No.3

Purpose: To identify risk factors influencing the anatomical and functional outcomes of canaliculoplasty in canalicular laceration patients. Methods: A retrospective investigation of 122 eyes of 122 patients diagnosed with canalicular laceration and treated in our hospital from January 2000 to October 2008 was conducted. Sex, age, cause and location of laceration, combined injury, preoperative duration, combined operation, duration of follow-up, and anatomical and functional outcomes of canaliculoplasty were investigated. Results: The mean age of the 122 patients was 41.2 years; 102 (83.6%) were men, and 20 (16.4%) were women. The most common cause and combined injury of laceration was sharp object Injury (20.5%) and orbital wall fracture (14.7%). No statistically significant correlation was found between pretreatment duration, duration of silicone tube insertion, and anatomical outcome. The causes of decreasing functional outcome of canaliculoplasty were traumatic facial nerve palsy, cicatrical entropion and ectropion, and partial canalicular obstruction. Conclusions: Repair of a combined eyelid injury close to the normal anatomical structure is an important factor for increasing the functional outcome. J Korean Ophthalmol Soc 2011;52(3):261-265

FBG 온도센서를 이용한 전력용 변압기 과열감시 시스템 연구

김우진(Woo-Jin Kim),박형준(Hyoung-jun Park),송민호(Min-Ho Song),이준호(June-Ho Lee) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.10

대형화, 고압화되고 있는 전력설비는 사고가 발생할 경우 그에 수반되는 산업, 경제, 사회적인 손실의 규모가 매우 커지는 경향을 가진다. 특히 적정온도 이상에서의 운전은 전력섣비의 오동작을 일으키는 주요한 원인 중 하나이므로 비정상적인 온도상승을 조기에 감지하여 사고의 가능성을 감소시키는 시스템의 개발은 안정적인 전역설비 운용에 반드시 필요한 요소기술이다. 기존의 감시 시스템은 대부분 여러 위치의 정보를 동시에 얻기 위하여 여러 개의 개별 센서를 배열하여야하므로 대형중량화가 불가피하다는 단점을 갖고 있다. 그러나 광섬유 FBG 온도센서는 선자기 간섭의 영향을 받지 않고, 여러 개의 센서를 하나의 광섬유 라인에 설치하여 동시에 여러 부위의 온도를 측정할 수 있는 준분배형 온도센서 구현이 가능하다는 장점으로 과열감시 시스템에 적합한 센서로 인식된다. 본 연구에서는 광섬유 FBG 온도센서를 이용하여 변압기 단락시험을 통해 변압기의 온도 변화를 T-type thermocouple(이하 TC)과 동일한 지점에서 측정하고, 그 데이터를 비교분석함으로써 광섬유 FBG 온도센서 시스템의 신뢰성을 검증하였고, 이를 전력용 변압기 과열감시 시스템으로 적용할 수 있음을 제시하였다.