• KSBB Journal
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• v.7 no.1
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• pp.79-83
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• 1992

The characteristics of Erwinia rhapontici cells with $\alpha$-glucosyltransferase activity immobilized in Ca-alginate beads and the performance of two different types of reactor-stirred tank reactor(STR) and packed bed reactor(PBR)-charged with these immobilized cells to produce palatinose from sucrose were investigated. The optimal pH(5.5-6.0) and temperature($30-35^{\circ}C$) showed no appreciable difference between free and immobilized cells. The apparent Km value of the immobilized cells(0.28M) was approximately two times higher than that of free cells(0.13M) at $30^{\circ}C$. The half life of the immobilized cells was found to be 380 h with STR while much greater operational stability was achieved with PBR. Continuous operation of PBR at a space velocity of $0.2h^{-1}$ for 30 days showed only 5% loss of initial activity.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.364-369
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• 2010

Resistivity data should be edited before the inversion because resistivity data are contaminated by a lot of noise. Generally, outlier or data violating pants-leg effect in dipole-dipole array were used to be rejected in the apparent resistivity pseudo-section. For more precise data editing, normalized voltage curves are used. In this study, we analyzed the behavior of normalized voltage curves for pole-pole, pole-dipole and dipole-dipole arrays in the presence of threedimensional inhomogeneities, and finally re-examined the validity of normalized voltage curves in the editing process of resistivity data.

• Elastomers and Composites
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• v.37 no.2
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• pp.124-133
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• 2002

Waste PBT powder was depolymerized by saponification under the mild temperature conditions($80{\sim}110^{\circ}C$) and atmospheric pressure. In depolymerization of PBT, sodium hydroxide was more effective than potassium hydroxide. The depolymerization increased with increasing reaction temperature and decreasing particle size. The reaction kinetics of depolymerization could be expressed by the shrinking unreacted core model without product layer, in which the surface reaction was a rate determining step. The activation energy was 98.1 KJ/mol. The recovery ratio of the TPA obtained from the depolymerized PBT particles of 85.1 and $105{\mu}m$ for 6 hours was about 95%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.1
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• pp.56-61
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• 2002

Porous clay ceramics was fabricated using the surfactant as a foaming agent in the secondary-clay produced at Young-Am area in Chun-Nam province. The concentration of surfactant in ceramic slurry was the key factor controlling the pore characteristics and physical properties of the porous ceramics. The more increase of the surfactant concentration increase the more foaming ability and the stability of foamed layer were improved, but the foaming ability was limited within 6.0 wt% of surfactant because the initial viscosity of the slurry increased with increasing the amounts of surfactant. The formed specimen were sintered at both $1150^{\circ}C$ and $1200^{\circ}C$, the porous ceramics showed 0.9 of specific gravity, 50% of water absorption, 45% of apparent porosity, 14% of shrinkage and 70 kg/$\textrm{cm}^2$ of compressive strength.

• Journal of the Korean Solar Energy Society
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• v.22 no.3
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• pp.57-65
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• 2002

The photocatalytic degradation of TCE using solar energy in POFR was studied. The use of solar energy was investigated in plastic optica fiber photocatalytic reactor (POFR). In POFR, the main parameters of photocatalytic degradation of TCE were lihgt intensity, thickness of $TiO_2$-coated film on plastic fiber core, the same of total $TiO_2$-coated surface area with changed length. We studied the apparent photonic efficiency and photocatalytic degradation rate of TCE in POFR. The apparent photonic efficiency of various light intensities was decreased by an incresed intensities. The photocatalytic activities of $TiO_2$-coated optical fiber reactor system depended on the coating thickness, and total clad-stripped surface area of POF. Photocatalytic degradation of trichloroethylene ($C_2HCl_3$, TCE) in the gas-phase was elucidated by using $TiO_2$-coated plastic optical fiber reactor. In TCE degradation, in-situ FTIR measurement resulted in mineralization into $CO_2$.

• Journal of the Korean Ceramic Society
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• v.33 no.7
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• pp.816-822
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• 1996

Dependence of graphitic structure on oxidation of carbon materials was discussed using furan resin-derived carbon with inorganic compounds such as SiC and TiO2 Oxidation of carbon was governed by active site. I. e surface area regardless of the degree of graphitization. When oxidation was considered for not unit weight but unit area graphitization was important factor for oxidation so that the degree of graphitization increased the oxidation rate was delayed. Graphite (tiO2 addition) and turbostratic graphite(SiC addition) were oxidized through the same mechanism. In carbon materials with different structure components more than 2 oxidation of each component was different and amorphous component without the influence of additives on the surface was selectively oxidized in the intial oxidation stage.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.21-21
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• 2011

개인적 삶의 질 향상과 함께 사회적인 삶의 가치를 추구하여 인체친화적이며 동시에 환경 친화적인 제품 소비에 가치를 두는 LOHAS 트렌드의 영향으로 의류 제품에서는 소비자의 요구 수준에 맞춘 고급화, 고기능화된 의류 상품 및 소재 중심의 소비와 함께 친환경 소재, 리사이클 소재 등에 대한 관심이 증가하고 있다. 최근 Ramie 복합 소재는 이러한 트렌드에 적합한 대표적인 소재로서 고감성/웰빙 신섬유 제품 개발을 통해 신시장 개척이 가능한 아이템으로 주목받고 있다. 한편, Ramie는 땀에 대한 흡습성과 속건성이 우수하고 청량감이 있어 주로 여름 소재로 활용되어 왔으나 촉감이 좋지 못하고 광택성이 떨어지는 단점이 있어 이를 보완하기 위해 촉감이 좋고 광택성이 뛰어난 레이온 계열의 소재와 혼방하여 고급스럽고 환경 친화적인 의류소재로써 개발이 진행되고 있다. 본 연구에서는 이러한 레이온계 섬유 중에서 상품성이 modal 섬유 Tencel 섬유를 각각 혼방한 Ramie/Modal(28's,30's), Ramie/Tencel(28's) 복합소재의 반응성 염료에 대한 염색특성을 비교 고찰해 보았다. 실험은 Heterobifunctional type 반응성 염료 3종(Red, Yellow, Blue)을 이용하여 흡진 거동, 빌드업 특성, 겉보기 색상농도 등을 비교하였으며 1/1 standard 농도에서의 제반 견뢰도를 비교 평가하였다.

• Applied Biological Chemistry
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• v.38 no.3
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• pp.232-238
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• 1995

Quality changes of high fructose corn syrups (HFCS) were investigated during storage at $-5{\sim}60^{\circ}C$. Color properties such as spectrophotometric properties, HMF and Hunter color value increased continuously during storage period. And the change was most evident as storage temperature and fructose content were elevated. High fructose corn syrups all showed flow behaviors as dilatant fluid and their viscosities increased slightly during storage. Content of fructose decreased, while glucose, maltose and oligosaccharide contents increased during storage. Especially, crystallization of what was observed below $13^{\circ}C$ during storage.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.69-75
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• 2014

The shear strength characteristics of an unsaturated earth material are highly important not only for evaluating the seepage characteristics but also the stability of levee for a lifelong. In this study, unsaturated strength characteristics of Nak-dong river sand and clay that frequently used for the levee construction in southern province of Korea were analyzed using unsaturated triaxial compressive test. The strength characteristics due to the variation of matric suction were analyzed using multi-stage compression technique and the results were directly compared with the non-linear formulation for the apparent cohesion ($C_{max}$), and the friction component ${\varphi}^b$ were determined and evaluated from the test for the application of linear Mohr-Coulomb failure criteria. Cohesion and friction characteristics of the unsaturated levee material under various suction phases were also explored during this study.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.333-333
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• 2010

크라이오 펌프는 크기에 비해 상대적으로 큰 배기속도를 가지고 있고 자체 기체 방출이 적어 비교적 쉽고 빠르게 도달압력을 낮출 수 있다. 또 초고진공 펌프로서 경쟁 상대인 터보분자 펌프보다 기체 돌입에 대한 기계적 사고 가능성이 낮다. 그러나 흡착 패널의 온도에 민감하게 반응하는 배기 성능 측면에서 볼 때 크라이오 펌프의 대유량 및 펄스 기체 부하에 대한 성능 유지 및 회복능력은 의문의 여지가 있다. 크라이오 펌프의 기체부하에 대한 공식적인 성능지표로는 최대배기량(max. throughput)과 교차(crossover)값이 있다. 전자는 연속적인 유량[$Pa{\cdot}m^3/s$]에 대해, 또 후자는 일정 기체량[$Pa{\cdot}m^3$]에 대해 흡착 패널이 20 K를 넘지 않는 가동범위를 구하는 것이다. 교차값은 넓은 의미에서 펄스 기체부하에 대한 성능으로 볼 수도 있지만 원래 목적은 진공용기를 저진공 상태에서 고진공 상태로 전환하는 시점을 정하려는 데 있다. 펌프회사에서 제공하는 사양에는 대부분 아르곤 회복시간(Ar recovery time)이라는 지표가 있는데 이는 아르곤을 상당한 유량으로 흘리다 멈췄을 때 얼마나 빨리 기저 상태로 회복되는가를 나타낸다. 보통 사양서에 제시하지는 않지만 주로 크라이오 펌프의 재생상태를 알아보기 위해 사용하는 걸프(gulp) 시험이 있는데 일정량의 기체를 펄스로 도입한 후 압력변화를 기록하여 재생후 배기성능 회복 능력을 보는 것이다. 이들은 겉보기에 서로 다르지만 한편으로는 서로 중복되거나 연관성을 가지고 있어서 실용적인 면에서 절차들을 비교, 검토 및 개선하고 때에 따라서는 적절히 결합할 수 있는 방안을 모색할 필요성이 있다.