AZO/Ni/SnO 2 적층박막의 전기적, 광학적 특성 연구

송영환,차병철,천주용,엄태영,김유성,김대일 한국열처리공학회 2017 熱處理工學會誌 Vol.30 No.1

SnO2 single layer films and 2 nm thick Ni thin film intermediated AZO/Ni/SnO2 trilayer films were deposited on glass substrate at room temperatures by RF and DC magnetron sputtering and then the optical and electrical properties of the films were investigated to enhance opto-electrical performance of SnO2 single layer films. As deposited SnO2 films show the optical transmittance of 81.8% in the visible wavelength region and a resistivity of 1.2×10−2 Ω cm, while AZO/Ni/SnO2 films show a lower resistivity of 5.8×10−3 Ω cm and an optical transmittance of 77.1% in this study. Since AZO/Ni/SnO2 films show the higher figure of merit than that of the SnO2 single layer films, it is supposed that the AZO/Ni/SnO2 films can assure high opto-electrical performance for use as a transparent conducting oxide in various display applications.

논문 : 수산분야에서의 생명공학기술의 응용

송영환 한국수산경영기술연구원 1997 수산연구 Vol.11 No.-

도축돈 장분변으로부터 Shiga Toxin-Producing Escherichia coli의 분리와 성상

송영환,김지영,채미경,박창식,김명철,전무형 충남대학교 형질전환복제돼지연구센터 2007 논문집 Vol. No.10

Shiga toxin-producing Escherichia coli (STEC) causes various clinical signs in human and animals, and has been indicated as a global enteropathogen with zoonotic importance. In this study, the feces of healthy pigs were collected from the slaughtered pigs of Daejon abattoir during the period from December 2001 to October 2002. Of 326 specimens, 13 STEC were confirmed by culture, PCR and colony hybridization. The isolates were further studied for toxin types, pathogenic factors, plasmid profiles, and antimicrobial resistance to characterize the genetic and toxigenic properties. In PCR, all of 13 isolates were evident to have shiga toxin gene (stx). Of 13 isolates stx1 gene was detected in 4 and stx2 gene in 9. The genes of eaeA, hlyA and rfbE were not present in any isolates. In colony hybridization using shiga toxin common primer (STXc), 2 to 9 per 100 colonies subcultured from 13 isolates showed the positive reaction. In the examination for plasmid profiles of the isolates, one to eleven plasmids with varying sizes of 1.0 Kb to 100 Kb were detected, and the 13 STEC could be classified into four groups by the plasmid patterns. The antimicrobial resistance patterns of the isolates were comparably corresponded with the plasmid profile patterns.

연속음성신호의 SNR 추정기법에 관한 연구

송영환,박형우,배명진,Song, Young-Hwan,Park, Hyung-Woo,Bae, Myung-Jin 한국음향학회 2009 韓國音響學會誌 Vol.28 No.4

음성 신호처리 환경에서 잡음이 섞인 신호를 개선할 목적으로 음성향상 기법이 많이 이용되고 있다. 잡음추정 알고리즘은 변화하는 환경에 빠르게 적응할 수 있어야 하며 음성신호의 영향을 줄이기 위해 음성신호가 존재하지 않는 구간에서만 잡음의 파워를 갱신한다. 이러한 방법은 음성구간검출이 선행되어야 한다. 그러나 잡음에 열화된 음성신호에 묵음구간이 존재하지 않을 경우, 위와 같이 음성검출을 통한 묵음구간에서의 잡음 추정 방법 및 SNR 추정 방법이 적용될 수 없다. 본 논문에서는 묵음구간이 존재하지 않는 연속음성신호에서 SNR을 추정하는 기법을 제안한다. 유성음의 안정구간에서는 단구간 내 피치의 변화가 매우 작아 피치주기에 따른 음성신호의 파형이 유사하게 나타난다. 따라서 잡음이 음성에 부가되었을 때 피치주기에 따른 인접파형의 유사도를 통해 SNR을 추정한다. 무성음에서는 잡음의 영향이 수신신호의 성도성분 추정에 영향을 미치기 때문에 잡음환경에서 추정된 성도성분과 수신신호 스펙트럼 간의 거리를 이용하여 SNR을 추정한다. 마지막으로, 음성신호의 에너지가 유성음에 대부분 분포하기 때문에, 부가성 잡음 환경에서 유성음의 에너지를 음성신호의 에너지로 근사화하여 SNR을 추정할 수 있다. In speech signal processing, speech signal corrupted by noise should be enhanced to improve quality. Usually noise estimation methods need flexibility for variable environment. Noise profile is renewed on silence region to avoid effects of speech properties. So we have to preprocess finding voice region before noise estimation. However, if received signal does not have silence region, we cannot apply that method. In this paper, we proposed SNR estimation method for continuous speech signal. The waveform which is stationary region of voiced speech is very correlated by pitch period. So we can estimate the SNR by correlation of near waveform after dividing a frame for each pitch. For unvoiced speech signal, vocal track characteristic is reflected by noise, so we can estimate SNR by using spectral distance between spectrum of received signal and estimated vocal track. Lastly, energy of speech signal is mostly distributed on voiced region, so we can estimate SNR by the ratio of voiced region energy to unvoiced.

질소분위기 열처리에 따른 SnO 2 박막의 구조적, 전기광학적 특성 변화

송영환,엄태영,허성보,김준호,김대일 한국열처리공학회 2017 熱處理工學會誌 Vol.30 No.1

A 100 nm thick SnO2 thin films were prepared by radio frequency magnetron sputtering on glass substrates and then annealed in nitrogen atmosphere for 30 minutes at 100, 200, and 300oC, respectively. While the visible light transmittance and electrical resistivity of as deposited SnO2 films were 81.8% and 1.5 × 10−2 Ωcm, respectively, the films annealed at 200oC show the increased optical transmittance of 82.8% and the electrical resistivity also decreased as low as 4.3 × 10−3 Ωcm. From the observed results, it is concluded that post-deposition annealing in nitrogen atmosphere at 200oC is an attractive condition to optimize the optical and electrical properties of SnO2 thin films for the various display device applications.

고밀도 STS316L 합금 적층 성형체의 제조공정 최적화 및 인장 특성 연구

송영환 한국결정성장학회 2023 한국결정성장학회지 Vol.33 No.6

STS316L 합금의 Laser powder bed fusion 공정 최적화를 위하여 Laser power, Scan speed 및 Hatching distance의 공정조건을 제어하면서 투입 레이저 에너지 밀도와 조형체의 상대밀도와의 상관관계를 연구했고, 최적조건으로 제작된 조형체의 적층 방향에 따른 인장특성 변화를 분석했다. STS316L 분말을 에너지밀도가 55.6J/mm3, 83.3 J/mm³ 및 111.1 J/mm³ 인 조건에서 적층 성형한 결과, 투입 레이저 에너지밀도가 83.3 J/mm³이며 , Power 및 Scan speed 각각 225 W, 1000 mm/s 인 조건에서 가장 안정적으로 고밀도 STS316L 샘플을 제작할 수 있었다 . 최적공정조건을 이용해 적층 방향과 인장방향이 각각 0°, 45°, 90°인 인장시험편을 제작하여 인장특성을 비교한 결과 적층 방향과 인장방향이 수직인 시험편의 항복강도, 인장강도 및 연신율이 가장 우수한 것이 확인되었다. 적층 방향과 수직 방향으로의 이방성을 가지는 기공 및 Lack of fusion 결함이 응력집중을 야기하여 인장특성을 열화 시키기 때문인 것으로 추정된다. To optimize the process parameters of laser powder bed fusion process to fabricate the high density STS316L alloy, the effect of laser power, scanning speed and hatching distance on the relative density was studied. Tensile properties of additively manufactured STS316L alloy using optimized parameters was also evaluated according to the build direction. As a result of additive manufacturing process under the energy density of 55.6 J/mm3, 83.3 J/mm³ and 111.1J/mm³, highdensity STS316L specimens was suitably fabricated when the energy density, power and scan speed were 83.3 J/mm³,225 W and 1000 mm/s, respectively. The yield strength, ultimate tensile strength, and elongation of STS316L specimens in direction perpendicular to the build direction, show the most competitive values. Anisotropic shape of the pores and thelack of fusion defects probably caused strain localization which result in deterioration of tensile properties.

도축돈 장분변으로부터 Shiga Toxin-Producing Escherchia coli의 분리 와 성상

송영환,김지영,채미경,박창식,김명철,전무형,Song, Young-hwan,Kim, Ji-young,Chae, Mi-kyung,Park, Chang-sik,Kim, Myung-chul,Jun, Moo-hyung 대한수의학회 2004 大韓獸醫學會誌 Vol.44 No.4

Shiga toxin-producing Escherichia coli (STEC) causes various clinical signs in human and animals, and has been indicated as a global enteropathogen with zoonotic importance. In this study, the feces of healthy pigs were collected from the slaughtered pigs of Daejon abattoir during the period from December 2001 to October 2002. Of 326 specimens, 13 STEC were confirmed by culture, PCR and colony hybridization. The isolates were further studied for toxin types, pathogenic factors, plasmid profiles, and antimicrobial resistance to characterize the genetic and toxigenic properties. In PCR, all of 13 isolates were evident to have shiga toxin gene (stx). Of 13 isolates stx1 gene was detected in 4 and stx2 gene in 9. The genes of eaeA, hlyA and rfbE were not present in any isolates. In colony hybridization using shiga toxin common primer (STXc), 2 to 9 per 100 colonies subcultured from 13 isolates showed the positive reaction. In the examination for plasmid profiles of the isolates, one to eleven plasmids with varying sizes of 1.0 Kb to 100 Kb were detected, and the 13 STEC could be classified into four groups by the plasmid patterns. The antimicrobial resistance patterns of the isolates were comparably corresponded with the plasmid profile patterns.

챠넬메기의 간 mRNA 로부터 분리한 metallothionein 유전자의 PCR 절편의 특성

송영환 한국어병학회 1997 한국어병학회지 Vol.10 No.1

Metallothionein은 세균에서 척추동물에 이르기 까지 모든 생명체에 존재하며, 중금속의 세포내농도를 조절하는 중요한 단백질이다. 현재까지 metallothionein의 기능 및 유도기작에 관한 연구는 많이 진척되지는 않았으나, 여러 metallothionein 유전자의 구조가 밝혀져 있는 실정이다. 특히 어류의 metallothionein은 여러종류의 중금속과 환경적인 자극에 의하여 유도되고 정량적인 RT-PCR의 방법으로 metallothionein 유전자의 RNA transcript를 측정함으로써 환경적인 자극의 정도와 중금 속의 상대적인 양을 측정할 수 있기 때문에 중요한 단백질로 인식되고 있다. 본 연구에서는 유전자내부의 특이적 primer와 통상적인 3'말단의 primer를 이용하여 PCR에 의해 450 bp에 해당하는 metallothionein 유전자의 일부의 특성을 조사하였다. 챠넬메기의 cDNA library로부터 PCR에 의해 증폭된 450 bp의 PCR 절편은 다른 어류의 metallothionein 유전자와는 유사성을 보이지 않았다. Metallothionein is an important and essential protein to control the intracellular concentration of heavy metals, which exist in all organisms from bacteria to vertebrates. Although the detailed functions and induction mechanisms of metallothionein gene have not been clearly characterized until yet, the structure of several metallothionein genes has been revealed. Especially, piscine metallothionein is regarded as an important protein because it is induced by several heavy metal pollutants and environmental stress and it could be determined the comparative amount of heavy metals and the extent of environmental stress by assaying the RNA transcript of metallothionein gene in the method of the quantitative RT-PCR(Reverse Transcriptase Polymerase Chain Reaction). In this study I have characterized the 450 bp PCR fragment of metallothionein gene amplified by using the mixture of internal specific primers and universal 3' end primer. The nucleotide sequence analysis of 450 bp PCR fragment amplified in cDNA library of channel catfish did not show strong homology to other piscine metallothionein genes.

유전자 구조 분석을 위한 컴퓨터 프로그램의 개발

송영환,이동훈,강현삼 한국유전학회 1984 Genes & Genomics Vol.6 No.3

N/A

보행 혈압 측정과 심장 기능의 관계

송영환 대한소아청소년과학회 2009 Clinical and Experimental Pediatrics (CEP) Vol.52 No.7

It is well known that hemodynamic load is one of the most important determinants of cardiac structure and function. Circadian variations in blood pressure (BP) are usually accompanied by consensual changes in peripheral resistance and/or cardiac output. In recent years, reduction in circadian variations in BP and, in particular, loss of nocturnal decline of BP were observed in hypertensive patients with left ventricular hypertrophy (LVH). The patients with only a slight or no loss of nocturnal decline of BP were considered "non-dippers". Regression of LVH was observed after prolonged antihypertensive therapy. Restoration of the circadian rhythm of BP was also observed. However, the classification of patients into "dippers" and "non-dippers" is arbitrary and poorly standardized and repeatable, and in the recent studies, most hypertensive patients with LVH were "dippers". Therefore, we should be particularly cautious about the conclusions drawn using this index. On the other hand, reduced activity of low- pressure cardiopulmonary baroreceptors and impaired day-to-night modulation of autonomic nervous system activity were observed in patients with only LVH. Therefore, alterations in cardiac structure may impair BP modulation. On the other hand, the reverse can also be trueprimary alterations in BP modulation, through a persistently elevated afterload, can increase cardiac mass. Thus, the interrelationship between cardiac structure and BP modulation is complex. Hence, new and more specific methods of evaluating circadian changes in BP are needed to better clarify the abovementioned reciprocal influences.