ZnO 박막의 fluorine-계 유도결합 플라즈마 식각

박종천,이병우,김병익,조현,Park, Jong-Cheon,Lee, Byeong-Woo,Kim, Byeong-Ik,Cho, Hyun 한국결정성장학회 2011 韓國結晶成長學會誌 Vol.21 No.6

$CF_4$ Ar 및 $SF_6$/Ar 유도결합 플라즈마을 이용하여 ZnO 박막의 고이온밀도 플라즈마 식각을 수행하였다. $10CF_4$/5Ar, $10SF_6$/5Ar 유도결합 플라즈마에서 최고 ~1950 ${\AA}$/min과 ~1400 ${\AA}$/min의 식각 속도를 확보하였다. 대부분의 조건 하에서 식각된 ZnO 표면은 식각 전보다 더 낮은 표면조도 값들을 나타내었다. $10CF_4$/5Ar 유도결합 플라즈마에서 Ni mask는 ZnO에 대해 최고 11의 높은 식각 선택도를 나타낸 반면에 Al은 이보다 낮은 1.6~4.7 범위의 식각선택도를 나타내었다. High density plasma etching of ZnO film was performed in $CF_4$/Ar and $SF_6$/Ar inductively coupled plasmas. Maximum etch rates of ~1950 ${\AA}$/min and ~1400 ${\AA}$/min were obtained for $10CF_4$/5Ar and $10SF_6$/5Ar ICP discharges, respectively. The etched ZnO surfaces showed better RMS roughness values than the unetched control sample under most of the conditions examined. In the $10CF_4$/5Ar ICP discharges, very high etch selectivities were obtained for ZnO over Ni (max. 11) while Al showed etch selectivities in the range of 1.6~4.7 to ZnO.

Schwanniomyces castellii CBS 2863으로부터 ${\alpha}$-Amylase 유전자 Cloning

박종천,배석,전순배,Park, Jong-Chun,Bai, Suk,Chun, Bai-CHun 한국미생물학회 1994 미생물학회지 Vol.32 No.1

Schwanniomyces castellii의 제놈 DNA로 제조된 유전자 은행으로부터 cloning된 ${\alpha}$-amylase 유전자가 Sacchromyces cerevisiae에서 발현되었다. Cloning된 삽입 DNA 절편의 크기는 약 5.0 kb이었고, Southern 및 immunoblot 분석 결과 cloning된 ${\alpha}$-amylase 유전자가 Sch. Castellii로부터 유래되었음이 확인되었다. S. cerevisiae SHY3 형질전환체에서 Sch. Castellii ${\alpha}$-amylase 유전자발현은 모균주에 비해 낮았으나, 단백질의 분자량 및 효소의 성질은 Sch. Castellii에서 분리한 ${\alpha}$-amylase의 그것과 차이가 없었다. The gene encoding ${\alpha}$-amylase of Schwanniomyces castellii was cloned in Saccharomyces cerevisiae. The 5.0-kilobase insert was shown to direct the synthesis of ${\alpha}$-amylase. Southern blot analysis confirmed that this ${\alpha}$-amylase gene was derived from the genomic DNA of Sch. castellii. Immunoblot analysis showed that ${\alpha}$-amylase production from S. cerevisiae transformant was less than that of donor strain. The ${\alpha}$-amylase secreted from S. cerevisiae transformant was shown to be indistinguishable from that of Sch. castellii on the basis of molecular weight and enzyme properties.

Schwanniomyces castellii CBS 2863(ATCC 26077)으로부터 $\alpha$-Amylase 정제 및 특성

박종천,배석,임선영,이진종,이향,전순배,Park, Jong-Chun,Bai, Suk,Lim, Suhn-Young,Lee, Jin-Jong,Lee, Hyang,Chun, Soon-Bai 한국미생물·생명공학회 1993 한국미생물·생명공학회지 Vol.21 No.6

The extracellular alpha-amylase was purified to homogenity from the culture filtrate of starch grown Sch. castellii CBS 2863. The purified enzyme was glycoprotein with a molecular weight of about 56 kDa. The pH and temperature optimum were 5.5 and 40C, respectively. The enzyme was fairly stable up to 40C and at acid pH range (pH 4.0-7.0). The apparent Km and Vmax of the enzyme toward starch was 1.0mg/ml and 100U/mg protein, respectively. The analysis of amino acid composition was found to be acidic protein. The amino acid sequence of N-terminal peptide consisted of Asp-Val-Ser-Ser-Ala-X-X-Thr-Arg-Ser-Glu-Ser-Ile-Tyr.

나노다이아몬드 seed 입자의 열처리에 의한 핵형성 밀도 향상

박종천,정옥근,손빛나,조현,Park, Jong Cheon,Jeong, Ok Geun,Son, Bit Na,Cho, Hyun 한국결정성장학회 2013 韓國結晶成長學會誌 Vol.23 No.6

산화 및 수소 분위기 열처리를 통한 화학적 표면 개질로 나노다이아몬드 seed 입자의 응집성 완화 및 초미세나노결정질 다이아몬드 (UNCD) 박막 증착을 위한 핵형성 밀도 향상을 확보하였다. 열처리에 의해 나노다이아몬드 seed 입자표면 작용기가 개질되었고, 제타 전위도 증가하였다. 또한, 응집체 평균 크기가 약 $2{\mu}m$에서 ~55 nm로 크게 감소하였다. $600^{\circ}C$, 수소 열처리된 seed 입자로 seeding 한 Si 기판으로부터 열처리하지 않은 seed 입자에 비해 현저하게 향상된 ${\sim}2.7{\times}10^{11}cm^{-2}$의 매우 높은 핵형성 밀도를 확보하였다. Surface chemical modification via air and hydrogen heat treatment was found to relieve the aggregation of nanodiamond (ND) seed particles and lead to a significantly enhanced nucleation density for ultrananocrystalline diamond (UNCD) film growth. After heat treatment in air and hydrogen, modification of surface functionalities and increase in the zeta potential were observed. Mean size of the ND aggregates was also dramatically reduced from ${\sim}2{\mu}m$ to ~55 nm. Si surface seeded with ND particles heat-treated at $600^{\circ}C$ in hydrogen produced a much higher nucleation density of ${\sim}2.7{\times}10^{11}cm^{-2}$ compared to untreated ND seeds.

가스 센서용 ZnO, SnO₂ 박막의 이방성 식각을 위한 mask 재료의 식각 선택도 조사

박종천,조현,Park, Jong-Cheon,Cho, Hyun 한국결정성장학회 2011 韓國結晶成長學會誌 Vol.21 No.4

고이온밀도 플라즈마 식각에 의한 고종횡비, 고이방성을 갖는 ZnO, $SnO_2$ 나노 구조 가스 감응층 형성을 위하여 mask 재료들과의 식각 선택도를 조사하였다. $25BCl_3$/10Ar ICP 플라즈마에서는 ZnO와 Ni 간 5.1~6.1 범위의 식각 선택도가 확보된 반면에 Al의 경우 효율적인 식각 선택도를 확보할 수 없었다. $25CF_4$/10Ar ICP 플라즈마에서는 ZnO와 Ni 간에 7~17 범위의 높은 식각 선택도를 얻을 수 있었다. $SnO_2$는 $SnF_x$ 식각 생성물의 높은 휘발성에 기인하여 Ni에 비해 매우 높은 식각 속도를 나타내었고, 최고치 약 67의 매우 높은 식각 선택도를 확보하였다. Etch selectivities of mask materials to ZnO and $SnO_2$ films were studied in $BCl_3$/Ar and $CF_4$/Ar inductively coupled plasmas for fabrication of nanostructure-based gas sensing layer with high aspect ratios. In $25BCl_3$/10Ar ICP discharges, selectivities of 5.1~6.1 were obtained for ZnO over Ni while no practical selectivity was obtained for ZnO over Al. High selectivities of 7 ~ 17 for ZnO over Ni were produced in $25CF_4$/10Ar mixtures. $SnO_2$ showed much higher etch rates than Ni and a maximum selectivity of 67 was observed for $SnO_2$ over Ni.

광양만 생태계의 미생물군집에 관한 환경요인 분석

박종천,이우범,주현수 ( Jong Chun Park,Woo Bum Lee,Hyun Soo Joo ) 한국환경생물학회 1998 환경생물 : 환경생물학회지 Vol.16 No.2

In Kwangyang bay, the biological and ecological surveys were carried out at seventeen sites both in surface and bottom water from July 1996 to May 1997. Fifteen abiotic and biotic parameters were determined on each sample. These data were subjected to simple regression, multiple stepwise regression and the principal factor analysis-to scrutinize the effect of environmental conditions on water quality and ecosystem. By the results of these analyses in Kwangyang bay, ecosystem were regulated by five factors for four seasons. The results showed that distribution of the microbial population was mainly influenced by inflow of fresh water, nitrogenous nutrients, suspended solids and water temperature. The overall size of microbial population was greater ten and five times than those obtained in 1982 and 1992, respectively.

나노결정질 다이아몬드 seeding 효율 향상을 위한 silicon 표면 texturing

박종천,정옥근,김상윤,박세진,윤영훈,조현,Park, Jong Cheon,Jeong, Ok Geun,Kim, Sang Youn,Park, Se Jin,Yun, Young-Hoon,Cho, Hyun 한국결정성장학회 2013 한국결정성장학회지 Vol.23 No.2

나노결정질 다이아몬드 박막 증착을 위한 전처리 공정으로 $SF_6/O_2$ 유도결합 플라즈마를 이용하여 Si 기판 표면을 texturing하였다. $SF_6/O_2$ 플라즈마 texturing은 2~16 범위의 매우 넓은 정규화된 표면 조도 선택성을 제공할 수 있음을 확인하였다. Texturing된 Si 기판 표면의 나노 다이아몬드 입자 seeding 이후 기존 기계적 연마 전처리에 비해 현저히 향상된 ${\sim}6.5{\times}10^{10}cm^{-2}$의 높은 핵형성 밀도를 확보하였다. $SF_6/O_2$ inductively coupled plasmas were employed to texture Si surface as a pretreatment for nanocrystalline diamond film growth. It was found that the $SF_6/O_2$ plasma texturing provided a very wide process window where normalized roughness values in the range of 2~16 could be obtained. Significantly improved nucleation densities of ${\sim}6.5{\times}10^{10}cm^{-2}$ compared to conventional mechanical abrasion were achieved after seeding for the textured Si substrate.

Schwanniomyces occidentalis var. persoonii CBS 2169 $\alpha$-Amylase 유전자의 Nucleotide Sequence

박종천,배석,오상진,이진종,전순배,Park, Jong-Chun,Bai, Suk,Oh, Sang-Jin,Lee, Jin-Jong,Chun, Soon-Bai 한국미생물·생명공학회 1993 한국미생물·생명공학회지 Vol.21 No.6

The relationship between Schwanniomyces occidentalis CBS 2863 (formerly castellii) and CBS 1153 (formerly alluvius), and their variety persoonii was examined at alpha-amylase gene level. Using Sch. occidentalis alpha-amylase gene as probe, Sch. occidentalis alpha-amylase gene homologues were obtained from Sch. occidentalis CBS 1153 and Sch. occidentalis var. persoonii. The restriction analysis of these homologues showed that the restriction enzyme sites between Sch. occidentalis CBS 2863 and CBS 1153 was identical but different between these strains and Sch. occidentalis var. persoonii.

아라 서해갑문을 만나다

박종천,Park, Jong-Cheon 한국수자원학회 2012 물과 미래(한국수자원학회지) Vol.45 No.4

광양만의 퇴적물에 대한 이화학적 조성 및 중금속 함량

박종천,김진,이우범,이성우,주현수,Park, Jong-Chun,Kim, Jin,Lee, Woo-Bum,Lee, Sung-Woo,Joo, Hyun-Soo 한국하천호수학회 2000 생태와 환경 Vol.33 No.1

본 연구는 광양만 퇴적물의 이화학적 조성과 중금속 함량을 알아보기 위해 함수율, COD, $H_{2}S$, 입도 및 10가지의 중금속을 17개 조사지점에 대해 분석${\cdot}$조사하였다. 조사기간동안 나타난 결과로서 퇴적물의 함수율 변화는 35.5${\sim}$53.8%를 나타내었다. COD와 $H_{2}S$는 각각 3.8${\sim}$12.9 mg/g, 0.1${\sim}$11.4 ${\mu}g/g$를 나타내었다. 퇴적물 입도의 구성은 입경 $74{\mu}m$ 이하가 40.5${\sim}$86.7% 74${\mu}m$ 이상이 11.5${\sim}$43.0%로 나타났다. 등농도 분포도를 이용한 중금속의 공간분포로부터 광양만 퇴적물에 영향을 미치는 몇 곳의 배출원을 추정할 수 있었다. 중금속 배출원 중 여천공단 내의 신풍천, 쌍봉천 그리고 하수처리장의 방류수역이 주요 배출원으로 판정되었다. 중금속의 분석 결과를 US, EPA 비오염해역의 guideline에 비교할 때 납과 수은은 guideline에 모두 적합한 것으로 평가되었으나 망간, 아연, 구리, 철, 비소, 크롬 등은 guideline을 모두 상회하고 있었다. For the purpose of surveying the physicochemical composition of sediment collected from Kwangyang Bay, the percentage of water loss, COD, $H_2S$, grain size and 10 heavy metals were studied at 17 sites. During the surveying period, the changes of the percentage of water loss were appeared $35.5\;{\sim}\;53.8%$. COD and $H_2S$ were showed $3.8\l{\sim}\;12.9\;mg/g$, and $0.1\;{\sim}11.4\;{\mu}g/g$, respectively, In composition of grain size on the sediment, percentages of grain sizes under $74\;{\mu}m$ were varied from 40.5% to 86.7% and above $74\;{\mu}m$ were varied from 11.5% to 43.0%. From the spatial distribution of heavy metal using contour map, we can suppose some heavy metal discharges which affect sediment of Kwangyang Bay, It was estimated that Shinpung creek, Ssang-bong creek, and draining area of sewange treatment plant were the main discharge among the heavy metal output sources. By comparison between present study and heavy metal guideline of nonpolluted sea sediment that is provided by EPA, US, it was showed that the contents of Pb and Hg were acceptable but contents of Mn, Zn, Cu, Fe, As, and Cr were higher than those of EPA guideline.