• 미생물학회지
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• 제13권2호
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• pp.71-80
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• 1975

The neurotoxin of Clostridium botulinum type B was purified from a liquid culture. The purification steps consist of ammonium sulfate precipitation of whole culture, treatment of Polymin P(0.15%, v/v), gel filtration on Sephadex G-100 at pH5.6 and DEAE-Sephadex charomatography at pH8.0. The procedure recovered 17% of the toxin assayed in the starting culture. The toxin was homogeneous by sodium dodecyl sulfate(SDS)-polyacrylamide gel electrophoresis and had a molecular weight of 163,000. Subunits of 106,000 and 56,000 molecular weight were found when purified toxin was treated with a disulfide-reducing agent and electro phoresed on SDS-polyacrylamide gels.

• Journal of Microbiology and Biotechnology
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• 제8권4호
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• pp.301-304
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• 1998

Methylobacterium organophilum can use nitrogen in the form of ammonium ions ($($NH_4$)_2SO_4\;and\;NH_4Cl) and from nonammonium sources such as glycine, alanine, peptone, and yeast extract. When potassium was limited, significantly more PHB was produced when the ammonium ion was the nitrogen source rather than a nonammonium form. With ammonium, the amount of PHB produced was 0.50-0.53 g PHB/l or $52.0~53.2\%$ of the dry cell weight. If nitrogen was from a nonammonium source, the respective values were 0.04~0.06 g PHB/1 or $8.1~11.3\%$ of dry cell weight. When ammonium sulfate was the sole source of nitrogen under potassium-limited conditions, cell growth and PHB accumulation increased as the pH increased from 6.0 to 7.5. Cell growth and PHB amount at pH 7.5 were 2.50 g dry cell weight/1 and 1.40 g PHB/1, respectively.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.326-332
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• 2018

In this study,the result shows that polyvinyl alcohol-sodium alginate (PVA-SA) gel bead crosslinked with sodium sulfate are better among the different methods by comparing the relative mechanical strength, mechanical strength swelling and expansion coefficient of beads in water. Subsequently, anammox biomass entrapment by PVA-SA gel was introduced into continuous stirred tank reactor (CSTR). After 24 operation days, the nitrogen removal efficiency achieved 60%, while the nitrogen loading rate (NLR) was $0.14kgN/m^3/d$ and the experiment data indicated that PVA-SA gel bead crosslinked with sodium sulfate can be used to initiate anammox process. Furthermore, it is an alternative for culturing anammox in a long-term operation.

• 공업화학
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• 제16권2호
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• pp.243-249
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• 2005

회분식/순환식증류 반응시스템에서 Amberlyst 이온교환수지와 황산의 첨가에 따른 젓산의 에스테르화 반응을 고찰하였다. 회분식증류 반응시스템에서는(n-butanol/lactic acid = 4, $100^{\circ}C$) 물의 함유량이 적을수록, n-butanol/lactic acid의 몰비가 증가할수록 에스테르화 전환율이 높게 나타났다. 알코올의 종류에 따른 에스테르화 전환율을 비교 해본 결과 단순한 구조의 메탄올과 치환반응성이 뛰어난 tert-부탄올이 에탄올, n-부탄올, iso-부탄올에 비해 치환 반응에 의한 에스테르화 전환율이 높은 것으로 나타났다. 지속적으로 물을 제거하는 순환식증류 반응 시스템에서는 (n-butanol/ammonium lactate = 4, $115^{\circ}C$) Amberyst-15 고체산 촉매를 사용한 경우가 황산촉매를 사용한 경우보다 에스테르반응 전환율이 높게 나타났다. 고체산 촉매를 반응초기에 투입한 경우에는 에스테르 반응이 지속적으로 진행되었으나 황산촉매의 경우에는 초기단계의 반응속도에는 영향을 미치지 않는 것으로 나타났다. 이는 반응 초기에 투입한 황산이 ammonium lactate간의 반응을 통해 ammonium sulfate를 생성하는 중화반응에 우선적으로 참여하기 때문인 것으로 사료된다.

• 생명과학회지
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• 제16권3호
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• pp.420-426
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• 2006

노르웨이의 Oslo시 지역의 토양시료로부터 분리된 Bacillus sp. KMU-991를 이용하여 고추탄저병균인 Colletotruchum gloeosporioides KACC 40804에 대한 항진균 활성을 위한 배양 조건을 조사하였다. 항진균 물질의 생산은 기본배지로 TSB를 사용하였으며 탄소원으로 1.0% mannitol과 질소원으로 1.0% ammonium chloride를 첨가하였을 매 가장 높은 항진균 활성을 나타내었다. 배양조건으로는 $30^{\circ}C$, 180 rpm, 48시간 배양하였을 때 가장 높은 항진균 활성을 나타내었다. $30{\sim}60%$ ammonium sulfate 침전물을 첨가하였을 때 가장 양호한 항진균 활성을 나타내었으며 butanol을 이용하여 배양액 중에 존재하는 항진균 물질을 회수하여 다양한 작물병원성 곰팡이에 대한 spectrum을 조사한 결과 B. cinerea KACC 40573, C. orbiculare KACC 40808, F. oxysporum f. sp. radicus-lycopersici KACC 40537, P. cambivora KACC 40160, 그리고 R. solani AG-4 KACC 40142등에 대하여도 높은 항진균 활성을 나타내었다.

• 분석과학
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• 제30권4호
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• pp.182-193
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• 2017

In order to examine the variation characteristics of chemical compositions in relation to the inflow pathways of Asian dust, $PM_{10}$ and $PM_{2.5}$ aerosols were collected at Gosan site of Jeju Island during the Asian dust days between 2010 and 2015, and their chemical compositions were analyzed. The mean mass concentrations of $PM_{10}$ and $PM_{2.5}$ during Asian dust days were $130.0{\pm}90.2$ and $38.2{\pm}24.7{\mu}g/m^3$, respectively. The composition ratios of major secondary pollutants ($nss-SO_4{^{2-}}$, $NH_4{^+}$, $NO_3{^-}$) were high as 53.7 % for $PM_{10-2.5}$ and 90.6 % for $PM_{2.5}$. When the Asian dusts had been transported to the Korean Peninsula via Loess Plateau of central China, the concentrations of $nss-Ca^{2+}$, $NH_4{^+}$, $nss-SO_4{^{2-}}$, and $NO_3{^-}$ increased more noticeably. Whereas in case when the inflow pathways of Asian dust had been through the Bohai bay, the concentrations of the crustal species such as Al, Fe, and Ca were relatively high in coarse particles. The atmospheric aerosols were acidified largely by sulfuric and nitric acids. They were neutralized mainly by calcium carbonate in coarse particle mode passed through Manchuria area, but by ammonia in fine particle mode passed through Loess plateau and Bohai bay. Ammonium salts are assumed to exist as ammonium sulfate and ammonium nitrate in coarse particles, but mostly as ammonium sulfate in fine particles.

• 한국대기환경학회지
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• 제21권3호
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• pp.329-341
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• 2005

The purpose of this study is to study the $PM_{2.5}$ source characteristics affecting the Seoul area using a chemical mass balance (CMB) receptor model. This study was also to evaluate the $PM_{2.5}$ source profiles, which were directly measured and developed. Asian Dust Storm usually occurred in the spring, and very high $PM_{2.5}$ concentrations were observed in the fall among the sampling periods. So the ambient data collected in the spring and fall were evaluated. The CMB model results as well as the $PM_{2.5}$ source profiles were validated using the diagnostic categories, such as: source contribution estimate, t-statistic, R-square, Chi-square, and percent of total mass explained. In the spring months, the magnitude of $PM_{2.5}$ mass contributors was in the following order: Chinese aerosol $(31.7\%)>$ secondary aerosols ($22.3\%$: ammonium sulfate $13.4\%$ and ammonium nitrate $8.9\%)>$ vehicles ($16.1\%$: gasoline vehicle $1.4\%$ and diesel vehicles $14.7\%)>$biomass burning $(15.5\%)>$ geological material $(10.5\%)$. In the fall months, the general trend of the $PM_{2.5}$ mass contributors was the following: biomass burning $(31.1\%)>$ vehicles ($26.9\%$: gasoline vehicle $5.1\%$ and diesel vehicles $21.8\%)>$ secondary aerosols ($23.0\%$: ammonium sulfate $9.1\%$ and ammonium nitrate $13.9\%)>$ Chinese aerosol $(10.7\%)$. The results show that the $PM_{2.5}$ mass in the Seoul area was mainly affected by the Chinese area.

• 분석과학
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• 제11권3호
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• pp.213-221
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• 1998

Bromide, chloride, fluoride, nitrite, nitrate, sulfite, sulfate, perchlorate, chlorate 및 chlorite가 포함된 시료를 capillary zone electrophoresis(CZE)와 indirect UV detection 방법으로 분리하였다. 음이온류의 분리는 running buffer로 5 mM ammonium dichromate, 10 mM ammonium acetate, 20 mM diethylenetriamine, 10% methanol(pH 9.3)을 사용하였으며 전압은 cathode에 15 kV를 공급하였다. 또한 최초로 CZE에서 음이온의 정량이 가능하도록 각 이온들에 대한 regression과 detection limit를 결정하였고, 이 분석방법은 톨루엔을 흡입한 사람의 뇨, 부검 혈액, 폐수 및 폭약 등 시료에 적용하였으며, 음이온의 함량을 ion chromatograph(IC)와 비교 검토하였다.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.667-674
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• 2007

Phase behavior for the mixed aqueous surfactant systems of cationic octadecyl trimethyl ammonium chloride (OTAC)/anionic ammonium dodecyl sulfate (ADS)/water was examined. Below the total surfactant concentrations of 1.5 m molal, mixed micelles were formed. At the total surfactant concentrations higher than 1.5 m molal, there appeared a region where mixed micelles and vesicles coexist. As the surfactant concentration increased, the systems looked very turbid and much more vesicles were observed. The vesicles were spontaneously formed in this system and their existence was observed by negative-staining transmission electron microscopy (TEM), small-angle neutron scattering (SANS) and encapsulation efficiency of dye. The vesicle region was where the molar fraction α of ADS to the total mixed surfactant was from 0.1 to 0.7 and the total surfactant concentration was above 5 × 10-4 molality. The size and structure of the vesicles were determined from the TEM microphotographs and the SANS data. Their diameter ranged from 450 nm to 120μm and decreased with increasing total surfactant concentration. The lamellar thickness also decreased from 15 nm to 5 nm with increasing surfactant concentration and this may be responsible for the decrease in vesicle size with the surfactant concentration. The stability of vesicles was examined by UV spectroscopy and zeta potentiometry. The vesicles displayed long-term stability, as UV absorbance spectra remained unchanged over two months. The zeta potentials of the vesicles were large in magnitude (40-70 mV) and the observed longterm stability of the vesicles may be attributed to such high ζ potentials.

• Current Research on Agriculture and Life Sciences
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• 제2권
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• pp.1-8
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• 1984

기계이앙용(機械移秧用) 상자육묘(箱子育苗)에 있어서 비료(肥料)의 종류(種類) 및 시비법(施肥法)이 토양(土壤)의 pH변화(變化)와 묘생육(苗生育)에 미치는 영향(影響)을 구명(究明)하고자 낙동(洛東)벼와 삼강(三綱)벼를 공시(供試)하여 시험(試驗)하였던 결과(結果)를 요약(要約)하면 다음과 같다. 초장(草長)과 건물중(乾物重)에 있어서 유안(硫安)을 시용(施用)한 것이 요소(尿素)를 시용(施用)한 것보다 양호(良好)하였으며 발근력(發根力) 또한 시비법(施肥法)에 관계(關係)없이 유안(硫安)을 시용(施用)한 구(區)가 요소(尿素)를 시용(施用)한 구(區)보다 양호(良好)한 것으로 나타났다. 생리장해(生理障害)는 요소전량기비구(尿素全量基肥區)가 요소분시구(尿素分施區)보다 심하였고 유안시용구(硫安施用區)에서는 거의 발생되지 않았다. 묘생육기간중(苗生育期間中) 상토(床土)의 pH변화(變化)는 질소질(質素質) 비료(肥料)는 유안(硫安)이 요소(尿素)보다 낮았고 인산질비료(燐酸質肥料)는 과인산석회(過燐酸石灰)가 용성인비(熔成燐肥)보다 낮았다.