• 한국환경과학회지
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• 제11권12호
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• pp.1315-1320
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• 2002

Since the enzymatic degradation of microbial poly[(R)-3-hydroxybutyrate-co-3-hydroxyvalerate] (P(3HB-co-3HV)) initially occurs by a surface erosion process, a degradation behavior could be controlled by the change of surface property. In order to control the rate of enzymatic degradation, plasma gas discharge and blending techniques were used to modify the surface of microbial P(3HB-co-3HV). The surface hydrophobic property of P(3HB-co-3HV) film was introduced by CF$_3$H plasma exposure. Also, the addition of small amount of polystyrene as a non-degradable polymer with lower surface energy to P(3HB-co-3HV) has been studied. The enzymatic degradation was carried out at 37 $^{\circ}C$ in 0.1 M potassium phosphate buffer (pH 7.4) in the presence of an extracellular PHB depolymerase purified from Alcaligenes facalis T1. Both results showed the significant retardation of enzymatic erosion due to the hydrophobicity and the enzyme inactivity of the fluorinated- and PS-enriched surface layers.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권2호
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• pp.121-126
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• 2006

Saikosaponin productivity was examined in a Bupleurum falcatum L. BFHR2 hairy root culture in response to changes in the sucrose content $(2{\sim}8%)$, nitrogen content $(0{\sim}250mM\;NH_4NO_3)$, phosphate content $(0{\sim}12mM\;NaH_2PO_4)$, and the potassium content $(0{\sim}87.2 mM\; KCl)$ of the culture media. We found that the conditions for maximal saikosaponin production differed from those for optimal root growth. Highest saikosaponin yield was achieved for 8% sucrose, 62mM $NH_4NO_3$ 1.2 mM $NaH_2PO_4$, and 0.5mM KCl.

• 한국초지조사료학회지
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• 제16권2호
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• pp.139-146
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• 1996

An experiment was canied out to investigate how to effect the application of nitrogen, phosphate and potassium on the vegetation and dry matter yield in the mixed sward of Ladino clover and crabgrass(Digitaria sanguinalis [L.] Scop.). The experimental sward was consisted of eight plots of non-application, K, P, PK, N, NK, NP and NPK. These plots were sown with seeds mixture of Ladino clover 5.0kg/ha and crabgrass 17.5kg/ha on 17 April 1976 in the forage experimental field of Kangwon National University, Chunchon, Korea, and were cut three times from 6 July to 4 October 1976.

• KSBB Journal
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• 제17권4호
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• pp.339-344
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• 2002

Flow injection analysis technique for monitoring of xylitol concentrations in biological processes has been developed using xylitol oxidase (XYO) immobilized on VA-Epoxy Biosynth carrier. The immobilized XYO cartridge has been integrated into a FIA system with an oxygen electrode and systematically investigated with regards to the factors which can affect the activity of the immobilized XYO, such as pH, temperature, salt concentration etc. The activity of the immobilized XYO increased with the temperature ($19.0 - 29.0^{circ}C$) and sample injection volume ($75-250\muL$) and molarity of potassium phosphate buffer (0.1-1 M), but it reached the highest value at pH 8.5. The XYO-FIA system has been also applied for on-line monitoring of xylitol concentrations in a reactor and showed good operational stability and agreement with off-line data measured with HPLC.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.34-35
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• 2016

Most of the construction adhesive may contain harmful component to the human body with an organic adhesive. In addition, when the adhesive caused hydroquinone, alkyl benzophenone, etc, also it raises the skin diseases to workers. Therefore, the inorganic adhesive development is necessary. This study was a study to know adhesive strength properties that adhesive using a magnesium oxide according to the addition ratio of the retarder. It has experiments to two types of magnesium oxide and type and ratio of retarder differently.

• Corrosion Science and Technology
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• 제4권1호
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• pp.15-18
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• 2005

Hydroxyapatite(HAp) was synthesized using the waste sludge from semiconductor process and used as an anticorrosive pigment. The water absorption of coating pigmented with anticorrosive pigment and the corrosion at interface between coating and substrate were monitored using AC impedance techniques. The anticorrosive performance of HAp was compared with those of red lead(RL) and zinc potassium chromate(ZPC), which have been known as representative anticorrosive pigments. The amount of absorbed water in ZPC- and HAp- pigmented coatings was much higher compared to that in RL-pigmented and unpigmented film. However, it seems that the water absorbed into HAp- or ZPC-pigmented film is beneficial to anticorrosive function. The anticorrosive performance of HAp is superior or at least comparable to those of ZPC and RL. The excellent anticorrosive properties of HAp can be explained by its passivating ability, caused by the reaction of the soluble component of HAp with Fe to form iron phosphate in the presence of water.

• 미생물학회지
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• 제13권1호
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• pp.31-36
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• 1975

Chlorella ellipsoidea cells were cultured in a phosphate, magnesium, sulfur or potassium-free medium. Some portions of cells were taken out at intervals during the culture, and physiological activities such as growth rate, reproduction, photosynthetic activity, and biosynthesis of cholorophyll of macro-element deficient cells were measured. 1) Generally, growth rate, reproduction, photosynthetic activities, and biosynthesis of chlorophyll of the macro-element deficient cells decreased more or less, compared with those of the normal cells. 2) The growth and reproduction of the algal cells in sulfur, or magnesium free medium were retarted severely with the chlorosis ; the photosynthetic activity and the content of chlorophyll showed the same tendency. 3) It is considered that the decrease in growth rate of macro-element deficient Chlorella cells is due to the decrease in photosynthetic activity owing to the decrease in chlorophyll content of the cells.

• Plant Resources
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• 제7권3호
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• pp.181-186
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• 2004

To find out the optimum fertilizer level for high yielding variety, Paldanghomil, experiment was conducted with 15 compositions of fertilizer levels at the experiment field of forage rye in Sunchon National University from Sep. 1998 to Aug. 1999. The effects of nitrogen fertilizer on plant growth were large significant but increasing rate of application in potassium and phosphate fertilizers above 10kg/10a had negligible effects on plant growth. Raising nitrogen application rate of fertilizers turned out to be 18-10-10kg/l0a of N-P$_2$O$_{5}$-K$_2$O. Content of crude protein was the highest and that of crude fiber such as NDF, ADF, cellulose and lignin were lowest at this rate. Furthermore, IVDMD was high and dry matter yield were the highest at the optimum rate.e.

• 대한전자공학회논문지
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• 제7권2호
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• pp.1-12
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• 1970

본 논문에서는 선형전기광효과(Pockel 효과)를 이용하여 X대역 마이크로파(9375 MHz)를 광변조하는데 관하여 이론적인 해석과 실험적인 연구를 했다. 전기광 결정체 KDP를 공진형 변조기로 설계하여 z축으로 광선과 평행하게 마이크로파 전계를 인가하여 변조했다. 변조파 출력을 가변단락판의 위치변화에 따라 관찰했으며 /2에서 변조가 잘 개폐되는 것을 알았다. 또한 출력변조의 세기를 인가 전계의 세기를 변화시켜 측정하여 이론곡선과 비교해서 약 5%의 오차를 얻었다. 결과적으로 아직 해결되어야 할 문제는 많이 있지만 비교적 만족스러운 광변조기를 얻었다.

• 동아시아식생활학회지
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• 제5권3호
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• pp.233-238
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• 1995

CDP-choline is known as an intermediate of lecithin biosynthesis, and as an important drug for nervous diseases of the brain, For the bioconversion of CMP and choline to CDP-choline, ATP is required as an energy source. In these studies, the biosynthetic reaction of CDP-choline was coupled with ATP regenerating system by glycolysis. As a microorganism containing the highest conversion activity of CMP and choline to CDP-choline, Candida utilis ATCC 42416 was selected. The optimum reaction condition were 50mM choline chloride, 20mM CMP, 100mM potassium phosphate (pH8.0), 300mM glucose, 50mM MgSO4, 10% dried cells with shaking incubation at 3$0^{\circ}C$. The reaction was thus performed for 10 hours under the above optimum conditions. The concentration of CDP-choline was 16mM(80% in conversion ratio).