Molecular Phylogenetic Analyses of Three Synechococcus Strains Isolated from Seawater near the Ieodo Ocean Research Station

최동한,노재훈 한국해양과학기술원 2006 Ocean science journal Vol.41 No.4

Three Synechococcus strains were isolated from seawater near the Ieodo Ocean Research Station (IORS), and their 16S rDNA genes and the internal transcribed spacer (ITS) between the 16S and 23S rRNA genes were sequenced to investigate their phylogenetic relationships. Phylogenetic trees based on the 16S rDNA and ITS sequences showed that they clustered in the main MC-A Synechococcus group (subcluster 5.1), but formed branches differentiating them from the described clades. As the IORS is located in an area affected by diverse water masses, high Synechococcus diversity is expected in the area. Therefore, the IORS might be a good site to study the diversity, physiology, and distribution of the Synechococcus group.

후막형 γ-Fe₂O₃/ZrOCl₂·8H₂O 가스 감지 소자

최동한 경북대학교 센서기술연구소 1990 센서技術學術大會論文集 Vol.1 No.1

소자의 규격화가 용이하고 소형, 경량화가 가능하며 혼성 집적회로에 적용할 수 있는 철산화물계 후막형 가스 감지 소자를 제조하고 그 특성을 조사하였다. 모물질은 γ-Fe_(2)O_(2)를 사용하였고 ZrOCl_(2).8H_(2)O를 첨가제로 적용하였다. γ-Fe_(2)O_(2) 후막 소자는 별 다른 첨가물질없이도 부탄 가스에 대해 높은 감도를 나타내었고 가스에 대해 가장 높은 감도를 갖는 최적 열처리 온도는 400℃였다. 또한 소자의 최적 동작 온도는 300℃였다. ZrOCl_(2).8H_(2)O의 첨가로 인해 소자의 저항은 증가되었고 알코홀과 일산화탄소에 대한 감도가 증진되었다.

Niche partitioning of picocyanobacterial lineages in the oligotrophic northwestern Pacific Ocean

최동한,Karen E. Selph,JAE-HOONNOH 한국조류학회I 2015 ALGAE Vol.30 No.3

More than 20 and 10 clades / ecotypes of Synechococcus and Prochlorococcus, respectively, have been identified in various oceanic regions. However, their diversity has yet to be thoroughly studied in the northwest Pacific Ocean. Further, spatial distribution of Synechococcus clades in the oligotrophic oceans has been scarcely characterized. To elucidate picocyanobacterial lineage distribution in the northwest Pacific Ocean, 16S-23S internal transcribed spacer sequences of picocyanobacteria were sequenced by barcoded amplicon pyrosequencing method. Additional pyrosequencing library using a primer specific for the Synechococcus subcluster-5.1 was constructed to thoroughly understand Synechococcus diversity in the oligotrophic oceans. In warm pool area, Prochlorococcus was predominant and showed a distinct depthpartitioning between HLII and LL ecotypes. Despite low abundances, diverse Synechococcus clades appeared in the oligotrophic open ocean, showing both vertical and horizontal niche partitioning. Clade II was the predominant Synechococcus clade, especially in upper euphotic depths. In shallow and middle euphotic depths, clades UC-A, III, and CRD1 were distributed broadly. However, a distinct shift in the horizontal distribution was found at ca. 20° N. Conversely, clades XVII and CRD2 dominated at deep euphotic depths and constituted a higher proportion than clade II. These niche-partitioning of Synechococcus clades seemed to be related with temperature, nutrient concentration as well as iron concentration.

鐵酸化物系 半導體 가스센서

崔東漢 청주대학교 산업과학연구소 1990 産業科學硏究 Vol.8 No.-

Iron oxide thick film gas sensors have been fabricated by a screen-printing method. Their electrical and gas sensing characteristics were investigated. The sensitivity of a gamma Fe_(2)O_(3) thick film without any other catalysts heat treated at 400℃ for 2hrs is 90% in 5000 ppm C_(4)H_(10) ambient at the operating temperature of 300℃. The addition of ZrOCl_(2)·8H_(2)O to gamma Fe_(2)O_(3) enhanced the sensitivity to alcohol and CO gases. The gamma Fe_(2)O_(3)/ZrOCl_(2)·8H_(2)O (2w%) thick films heat greated at 400℃ for 2hrs showed the highest sensitivity to alcohol gas at the operating temperature of 300℃. And the gamma Fe_(2)O_(3) thick films with 0.5w% ZrOCl_(2)·8H_(2)O showed the highest sensitivity to CO gas.

NO_x 가스센서의 개발

최동한,전춘배 경북대학교 센서기술연구소 1993 연차보고서 Vol.1993 No.-

NO_x 가스 감지용 재료로 유망한 것으로 알려진 금속 프탈로시아닌을 이용하여 가스 감지막을 제조하고, 감지막의 증착조건과 동작조건에 따른 가스 감지특성을 조사하였다. 그 결과 가장 유망한 감지물질은 PbPc였다. 기판을 가열하지 않고 증착된 PbPc막은 170℃의 동작온도에서 가장 높은 감도를 나타내었다. 증착시 기판을 가열하였을 경우 가스에 대한 감도가 증진되었다. 기판의 온도를 100℃로 하여 제조된 PbPc막이 동작온도 170℃에서 가장 높은 감도를 나타내었다. 기판의 온도를 100℃로 하여 제조된 PbPc막은 동작온도 170℃에서 5ppm의 NO_2 가스에 대해 75%의 감도를 나타내었다. 동작온도가 170℃일때 PbPc막의 90% 응답속도와 회복시간은 5ppm의 NO_2 가스에 대해 각각 60초, 3분이었다. 또한 170℃의 연속동작시 60일까지는 장기 안정도 특성이 매우 우수하였다. The NO_x gas sensing layers using various metal phthalocyanine known for promising NO_x gas sensing material were fabricated and their gas sensing characteristics with film's preparing and operating conditions were investigated. The most promising sensing material was PbPc. The PbPc films prepared without substrate heating showed the highest sensitivity to NO_2 gas at an operating temperature of 170℃. The substrate heating during vacuum sublimation enhanced the sensitivity of PbPc films to NO_2 gas. The PbPc films prepared at 100℃ substrate temperature showed the highest sensitivity to NO_2 gas at an operating temperature of 170℃. The sensitivity of PbPc films prepared with 100℃ substrate heating to 5ppm NO_2 gas was 75% at an operating temperature of 170℃. The 90% response time and recovery time of PbPc films to 5ppm NO_2 gas was 60s., 3min., respectively, at an operating temperature of 170℃. The long-term stability of the film was excellent up to 60 days at 170℃ continuous operation.

철 산화물 후막의 부탄가스 감지특성

최동한 청주대학교 산업과학연구소 1998 産業科學硏究 Vol.15 No.3

γ-Fc₂O₃/Pt thick film butane gas sensors were fabricated and their sensing characteristics were investigated. The sensitivity of the film to butane was higher than that of any other gases, such as propane, methane, carbon monoxide and alcohol at an operating temperature of 300℃. The Pt 1wt% added γ-FE₂O₃ thick film showed the highest sensitivity to butane.

후막형 γ-Fe₂O₃가스센서의 감도에 대한 첨가물의 영향

최동한 경북대학교 센서기술연구소 1991 센서技術學術大會論文集 Vol.2 No.1

γ-Fe_(2)O_(3) thick film gas sensors were fabricated using screen-printing method. The effect of additives on the sensitivity of γ-Fe_(2)O_(3) thick film to hydrocarbon gases were investigated. The γ-Fe_(2)O_(3) thick film heat-treated at 400℃ for 2 hours containing 5w% ZrO_(2) show the highest sensitivity to butane and the selectivity characteristics were excellent. The sensor's response time was 20 seconds and the recovery time was about 3 minutes to 1000ppm C_(4)H_(10) in air at the operating temperature of 350℃.

후막형 알코올 가스 센서

최동한 청주대학교 산업과학연구소 2005 産業科學硏究 Vol.23 No.1

γ-Fe_(2)O_(3)/In_(2)O_(3) thick-film devices for detecting alcohol gas have been prepared by the painting technique, and their characteristics have been investigated. The sensitivity of an γ-Fe_(2)O_(3)/In_(2)O_(3) thick film to C_(2)H_(5)OH(100ppm) is 99.6% at an operating temperature of 250℃.

프탈로시아닌 박막의 NO_(2) 가스 감지 기구

최동한 청주대학교 산업과학연구소 1998 産業科學硏究 Vol.15 No.3

The sensing mechanisms of phthalocyanine thin films to NO₂ gas were proposed in this study. The proposed NO₂ gas sensing mechanisms of phthalocyanine were derived from the sensing mechanisms of metal oxides to reducing gases and the chemistry of gas-solid interactions. The derived equations were in good agreement with experimental data.

Pd를 첨가한 SnO_(2) 후막형 부탄가스 감지소자의 감도 증진 특성

최동한 청주대학교 산업과학연구소 1997 産業科學硏究 Vol.15 No.2

The nature of electronic interaction between noble metal and semiconducting oxide was investigated for Pd-loaded SnO₂ sensor elements. It was shown that SnO₂ grains contacting to PdO were strongly depleted of electrons in air. This electronic interaction disappears on exposure not only to H₂-containing air but also to He (inert gas). On the basis of these results, it was suggested that the adsorbed oxygen formed at the PdO-SnO₂ interface is responsible for the electronic interaction.