• Microbiology and Biotechnology Letters
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• v.13 no.2
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• pp.115-118
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• 1985

Rifamycin B oxidase converts rifamycin B to rifamycin S using oxygen as cosubstrate. Humnicola spp. (ATCC 20620) was treated with acetone and the cell powder was immobilized with cellulose acetate. The properties of the immobilized enzyme was examined. The optimum pHs of the immobilized and the free enzymes were 7.2. The optimum temperature of the immobilized enzyme was at 50-55$^{\circ}C$, which was 5$^{\circ}C$ higher than that of the free enzyme. The activities of the immobilized enzyme appeared less sensistive with respect to the changes of temperature and pH as compared to those of the free enzyme. Twenty percent of the enzyme activity was recovered when the enzyme was immobilized in 3mm beads. The storage stability was good below 4$0^{\circ}C$, but the activity decreased very rapidly above 5$0^{\circ}C$. The physical strength of the beads was good and was suitable as packing material in a three-phase enzyme reactor.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.201-206
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• 2020

Diversification of project delivery methods (PDM) under ever-changing construction business environment has significantly changed the role of project participants. Active efforts to effectively sharing the roles and responsibilities have been observed in the project management offices (PMOs) among owner/operator organizations as well as engineering, procurement, construction and maintenance (EPCM) firms. In order for being effective in a holistic way throughout the project life-cycle, a PMO needs to have 'adequate management skills' as well as 'essential technical capabilities' in cooperating with many different participants. One of the well-known examples of the PMO's tool to support these skills and capabilities is the effective 'work packaging (WP)' that serves as a common basis integrating all relevant information in a structured manner. In an attempt to enhance the construction productivity, the concept of 'advanced work packing (AWP)' has been introduced by Construction Industry Institute (CII). The AWP enables productivity to be improved by early planning of construction packages in the design phase "with the end in mind". The purpose of this study is to identify and evaluate the 'variables' of advanced work packing (AWP) for life-cycle information integration. Firstly, an extended concept of advanced WP based on the CII AWP was defined in order to comprehend many different issues of business functions (e.g. cost, schedule, quality, etc.). A structured list of major components and variables of AWP were then identified and examined for practical viability with real-world examples. Strategic fits and managerial effectiveness were stressed throughout the analyses. Findings, implications and lessons learned are briefly discussed as well.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3591-3596
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• 2013

The enantioselective aza-Morita Baylis Hillman reaction of nitroalkene and N-tosylimine catalyzed by thiourea-tertiary amine has been investigated using density functional theory. Enantioselectivity is dominated by the cooperative effect of non-covalent and weak covalent interactions imposed by different units of catalyst. As Lewis base, the tertiary amine unit activates nitroalkene via weak covalent bond. The weak covalent interaction orients the reaction in a major path with smaller variations of this bond. The aromatic ring unit activates N-tosylimine via ${\pi}-{\pi}$ stacking. The non-covalent interaction selects the major path with smaller changes of the efficient packing areas. Thiourea unit donates more compact H-bonded network for species of the major path. The calculated ee value in xylene solution phase (97.6%) is much higher than that in N,N-Dimethylformamide (27.2%). Our conclusion is also supported by NBO analysis.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.94-97
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• 1998

We have been studying :he synthesis of thermotropic polyurethanes, based on structural modifications by means of (i) the introduction of bulky substituent group in the aromatic ring to decrease the degree of lateral packing, (ii) the copolymerization of two kinds of monomers having different alkylene lengths to lower the regularity of the polymer structure, and (iii) the use of nonlinear monomers to lower the persistence length of the polymer chain in the liquid crystalline phase and to decrease the lateral interactions in the solid state. (omitted)

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.159-162
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• 2008

High pressure is involved during injection molding operation specially packing phase. Cracks in the mold are often occurred by high cavity pressure. In this study, structural analysis of mold has been performed using commercial softwares, Abaqus and Ansys, to investigate cause of crack in the injection mold. Structural analysis contains four cases: stress distribution according to the cavity pressure, stress concentration according to the boundary conditions, stress concentration for inter-locking design of mold, and stress concentration for distributed cavity pressure. Through this study it was observed that the locations of stress concentrations were coincident with locations of crack. Robust mold design is being required to withstand high cavity pressure.

• Analytical Science and Technology
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• v.5 no.2
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• pp.217-222
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• 1992

An attempt was made to analyze green microstructure of AIN samples prepared by slip casting and dry pressing through Hg-porosimetry. Slip cast samples with narrow pore size distribation and high packing density showed higher sinterability and homogeneous distribution of second phase(s). Hg-porosimetry is and effective way to determine pore structure if "ink bottle" phenomenon does not occur. A comparison study with porosity measurement by quantitative microscopy showed that the effectiveness of Hg-porosimetry measurement could be extended to higher sintered density as long as pores remained open.

• Archives of Pharmacal Research
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• v.19 no.2
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• pp.95-99
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• 1996

Four N-adamantyl n-alkanamides were prepared by amide condensation reaction between amantadine and n-alkanoic acid. Their enhancing activity on the penetration of ibuprofen through rabbit skin from petrolatum ointment was evaluated in in-vivo experiment. The experiments showed that the compounds have a strong transdermal penetration-enhancing activity, and their activities were comparable with that of Azone. The measurements of the fluorescence polarization of DP[-i-labelled DPPC liposomes showed that these compounds considerablly decreased the phase transition temperature of the liposomes. The mechanism of the transdermal penetration-enhancing activity of the compounds was ascribed to the reduction of the resistance to drug flux of the stratum corneum lipid layers due to the loose packing of the layers when the bulk head group of the enhancers inserts into the layers.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.297-300
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• 2008

High pressure is involved during injection molding operation specially packing phase. Cracks in the mold are often occurred by high cavity pressure. In this study, structural analysis of mold has been performed using commercial softwares, Abaqus and Ansys, to investigate cause of crack in the injection mold. Structural analysis contains four cases: stress distribution according to the cavity pressure, stress concentration according to the boundary conditions, stress concentration for inter-locking design of mold, and stress concentration for distributed cavity pressure. Through this study it was observed that the locations of stress concentrations were coincident with locations of crack. Robust mold design is being required to withstand high cavity pressure.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.331-333
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• 2003

The low-pH biofiltration system in laboratory experiments demonstrate defective performance for treating H2S. When leachate pH was in the range of 1.5 to 4, the biofilters in three different media removed H2S wi th efficiencies greater than 99％ while it was treated as a single contaminant. The posibility of using a single-stage low pH biofilter depends on its performance in treating VOCs. During Phase 2, a single-stage biofilter was effective for treating mixtures of H2S and toluene with toluene concentrations below 20ppm and leachate pH between 2 and 3.5. Biofiltration of xylene was ineffective when pH was lower than 1.5. The treatment system acclimated most slowly to benzene, and treatment of benzene was apparently subject to some competive inhibition from xylene and toluene. However. co-treatment was possible after some acclimation time. Xylene was not easily treated, with higher elimination capacities and no sign of competitive inhibition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1138-1147
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• 2012

In this paper, an efficient power control based MF-TDMA resource allocation scheme is proposed for next generation military satellite communication systems. The proposed scheme has the flexibility is used to support heterogeneous terminals with differ in transmission capabilities. The method can be divided into two parts : burst size calculation and burst structure determination. At first, we estimate the link budget taken into account a dynamic satellite link state variation. Then, applicable ACM level and burst size is chosen. In burst structure determination phase, we reorganize the burst structure in time-frequency domain by controlling limited power, bandwidth, time resources. In particular, we compensate the power spectral density among different terminals to integrate them in same transponder, Furthermore, we increase the packing efficiency by controlling the ACM level of the burst in applicable power spectral density range. Simulation results show that the method increase the spectral efficiency and burst packing efficiency. In addition, slot allocation rejection ratio is successfully reduced.