• Biotechnology and Bioprocess Engineering:BBE
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• 제3권1호
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• pp.48-49
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• 1998

A protocol for the transformation of Klebsiella oxytoca by electroporation was developed. Preparation of competent cells at early exponential phase was most critical to obtain high transformation efficiency. The highest efficiency of 1.6$\times$106 transformants per $\mu\textrm{g}$ DNA(pBR322) could be obtained by electroporation of K. oxytoca cells prepared at the OD600 of 0.2 with 1.25$\mu\textrm{g}$ DNA at the filed strength of 2.5kV, the parallel resistance of 200$\Omega$ and capacitance of 25$\mu$F.

• 한국염색가공학회지
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• 제12권5호
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• pp.273-279
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• 2000

Interlace textured yarn was developed in order to increase weaving process efficiency. Today, interlace texturing is very useful method of manufacturing the high added value compound yarns for new synthetic fabrics. In this research, new silky type high added value compound yarns were. manufactured by interlace texturing technology and tested their properties. The object of this research is to investigate the relationship between interlace textured yarn properties and processing parameters that is air pressure, yarn tension and take-up speed. The original filament yarns used were TTD(Thick & Thin Semi-Dull) 110d/72f and SCD(Semi-Dull Cation Dyeable) 75d/36f. 27 specimens were manufactured and tested for their physical properties-nip density, tensile properties, multi-step shrinkage test and surface structure by SEM. The air pressure was main process condition to change properties of interlace textured yarns. And interlace textured process had influence on weaving preparation process, weaving, knitting and so on. It has some influence on shrinkage properties of dyeing and finishing processes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.987-992
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• 2005

Manufacturing companies should perform process planning and its evaluation concurrently with new product developments so that they can be highly competitive in the modern market. Process planners should make decisions in the manner of concurrent and collaborative engineering in order to reduce the manufacturing preparation time and cost when developing new products. Automated generation of analysis models from the integrated database, which contains process and material information, reduces time to prepare analyses and makes the models reliable. In this research, we developed a web-based system for concurrent and collaborative system for production flow analysis, using web, database, and simulation technology. An integrated database is designed to automatically generate analysis models from process and material plans without reworking the data. This system enables process planners to evaluate their decision fast and share their opinions with others easily. With this system, it is possible to save time and cost for assembly process and material planning, and reliability of process plans can be improved

• Archives of Pharmacal Research
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• 제16권1호
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• pp.50-56
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• 1993

The microencapsulation of sodium naproxen with Eudragit. RS was studied by coacrtvation/phase separation process using Span 80 in mineral oil/acetone system. Various factors which affect the mciroencapsulation, e.g., stirring speed, and surfactant concentraction, Eudagit RS concentration and loading drug amounts were examined. For the evaluation of the prepared microcapsules, release rate, particle size distribution and surface appearance as well as in vivo test were carried out. The addition of n-hexane and freezing of microcapsules accelerated the hardening of microcapsules. The optimum concentration of Span 80 ti prepare the smallest microcapsules was the same value with the CMC of Span 80 in solvent system. When 1.5% (w/w) Span 80 was used, the smallest microcapsules were formed $(30.02\pm5.05\mu$ in diameter) belonging to the powder category showing smooth, round and uniform surface. The release of sodium naproxen was retarded by microencapsulation with Eudragit RS. The Eudragit RS microcapsules showed significantly increased AUC and MRT and deceased Cl/F in rabbits.

• 환경영향평가
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• 제4권2호
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• pp.151-156
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• 1995

Public participation in Environmental Impact Assessment (EIA) process has been implemented since the introduction of EIA project on August 1 1991, followed with Environmental Policy Act promulgation on August 1 1990. Though public participation has room for improvement. This study compared before and after the introduction of public participation on EIS preparation cost, project cost, EIS preparation term and project term through 293 EISs analysis. Also public opinions in EIS after introduction of public participation were analyzed. The results are expected to be contributed to the system improvement of public participation.

• 한국세라믹학회지
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• 제25권5호
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• pp.479-487
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• 1988

In this study we studied the function of Glycerol as a DCCA(Drying Control Chemical Additives) in the preparation of silica bulk glas through Sol-Gel method. We used TEOS(Tetra Ethyl Ortho Silicate) and maintained the mixing ratio of TEOS : H2O : EtOH : HCI as 1 : 4 : 4 : 0.0007(mol) and varied glycerol input quantity from 0.1vol% considering the ethnaol input quantity as 100vol%. We investigated the changes from Sol-Gel Synthetic solutions to the glass using DT-TG, FT-IR and other instruments. The results obtained from this experiment showed that the dried gels made from the synthetic solutions containing 0.1-1.0vol% of glycerol were easily heat-treated up to 85$0^{\circ}C$ so that transparant bulk silica glass was prepared.

• 한국세라믹학회지
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• 제22권6호
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• pp.87-93
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• 1985

The hematite the magetite and the maghemite thin film were prepared by oxidation and reductino of the vaccum-evaporated iron thin film. Interre;atoms between film preparation process and the electrical properties were investigated. At room temperature the electrical conductivity of the iron the hematite the magnetite and the maghemite thin film were $1{\times}10^4\Omega^{-1}cm^{-1}$, 2{\times}10^{-5}\Omega^{-1}cm^{-1}$, $3{\times}10^{-5}\Omega^{-1}cm^{-1}$, and $4{\times}10^{-5}\Omega^{-1}cm^{-1}$, resp-ectively. The surface of each thin film was dense and homogeneous. At the temperature that the iron thin film was converted into the hematite thin film the electrical conductivity decreased rapidly and the electrical con-ductivity of the hematite thin film increased as temperature increased. The hematite thin film was reduced to the magnetite thin film in H2 atmosphere. The electrical conductivity decreased rapidly at the temperature that the maghemite thin film is formed by oxidation of the magnetite thin film and the electrical conductivity of the maghemite thin film increased as temperature increased.

• 한국결정성장학회지
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• 제13권5호
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• pp.222-229
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• 2003

InP crystal is an increasingly important semiconductor material in the application of long-wave optoelectronic and high frequency devices. The equilibrium vapor pressure of phosphorus at the melting point of InP is so high that the synthesis process is very difficult. Liquid-encapsulated Czochralski (LEC) pulling from the melt at high pressure is a generally favored technique to grow InP single crystals. This technique involves two steps: the synthesis of polycrystalline powder and the growth of single crystal from the melt at high pressure. This article reviewed the latest development in the preparation of InP crystal and the evaluation on the crystal quality.

• 한국염색가공학회지
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• 제15권4호
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• pp.65-72
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• 2003

Poly(ethylene-co-vinylacetate) (EVA) microspheres were prepared by a thermally induced phase separation. Poly(vinyl Alcohol) (EVAL) microsphere with Core-Shell Structure were synthesized by a saponification on sheath of EVA microspheres. The size of EVA core/EVAL shell microsphere was decreased from $4.09\mu{m}\;to\;2.55\mu{m}$ by partial saponification of $NaOH/Na_2SO_4$/methanol(2 : 1 : 1 by weight) at $60^\circ{C}$ for 4h to produce a saponified surface layer of about 60% of original radius. In this process, the surface layer of EVAL microsphere was dissolved partially and morphology of surface was not showed. Add-on of cotton and silk printed with EVA core/EVAL shell microsphere was increased and that of printed PET was decreased. In case of EVA core/EVAL shell microsphere, Hand of cotton and silk printed was flexible and fullness.

• 한국세라믹학회지
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• 제31권9호
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• pp.957-968
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• 1994

Manufacturing process of porous glass by the filler method was studied. Commercial soda-lime-silicate glass powder was mixed with inorganic salt as the filler such as KCl, K2SO4, Na2SO4. Sintering shrinkages of mixed powders with the variation of sintering temperature were compared, and the effects of the fillers to shrinkages of mixed powder were increased in the order of Na2SO4${\mu}{\textrm}{m}$ of pore diameter were manufactured when the filler sizes 100~200 ${\mu}{\textrm}{m}$. The open pore volume of porous glass is determined by the quantity of filler and porous glasses having open pore volume between 30 and 70 vol% are available. Available sintering temperature range for preparation of porous glass is from the softening temperature of the glass powder to eutectic melting temperature of DTA curve of mixed powder.