• Journal of Microbiology and Biotechnology
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• v.6 no.1
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• pp.60-62
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• 1996

Aureobasidium pullulans produced three kinds of extracellular polyols e.g. glycerol, mannitol, and sorbitol from either sucrose, glucose, fructose or mannose. Sorbitol was selectively produced when urea was used as a sole nitrogen source, and the amounts of sorbitol produced rapidly reached a plateau after 50 h where its maximum quantity was about 20 g/l with sucrose.

• Transactions of Materials Processing
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• v.6 no.3
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• pp.192-202
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• 1997

This study presents an effect of number of passes in wire-cut electric discharge machining on fine blanking dies and products. Three part fine blanking dies were produced by the difference of numbers of passes discharge machining. Brake pad was produced, through the die produced like that, the objective of this study is the improvement in surface roughness of die block and punch, life extension of die block, the decrease of second fracture dimensions, the rise of productive.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.794-795
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• 2006

Metal powder for dust core application was developed. The powder can be produced improved high-pressure water atomization process. The process has produced powder of spherical shape and lower coercivity. The dust core obta ined shows lower core loss.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.2
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• pp.130-134
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• 2003

A visual method for the selective screen Eng of lignin degrading enzymes, produced by white rot fungi (WRF), was investigated by the addition of coloring additives to solid media. Of the additives used in the enzyme production media, guaiacol and RBBR could be used for the detection of lignin peroxidase (LiP), manganese peroxidase (MnP) and lactase. Syringaldazine and Acid Red 264 were able for the detection of both the MnP and lactase, and the LiP and laccase, respectively, and a combination of these two additives was able to detect each of the ligninases produced by the WRF on solid media.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.731-734
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• 2001

An efficient fermentation strategy for the high level production of ultra-high-molecular weight poly(3-hdyroxybutyrate) (PHB) was developed. Although the cell and PHA concentrations obtained by flask cultures at different initial pH (6.0 or 6.9) were almost same level, the molecular mass of PHB produced were quite different along with the initial pH. When a recombinant Escherichia coli XL1-Blue harboring pJC2 containing the Alcaligenes latus PHB biosynthesis genes was cultivated in flask culture (pH 6.0), the PHB having a very high molecular weight of 22 MDa could be produced while only below 1 MDa at initial pH 6.9. The ultra-high-molecular weight PHB could be synthesized to high concentration of 89.8 g/L resulting in the PHB productivity of 2.07 g/L-h by simple fed-batch culture. In this study, we report that PHB having various molecular mass can be produced by employing metabolically engineered E. coli strains harboring the plasmids of different copy numbers containing the A. latus phbCAB genes.

• Journal of Embryo Transfer
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• v.9 no.3
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• pp.229-234
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• 1994

This experiment was carried out to develop the model system for mass production of biomedical and nutritional proteins (human proteins) through mamraary gland of the transgenic cattle produced by gene manipulation and embryological technologies. Human growth hormone gene fused with rat $\beta$-casein gene promoter was microinjected into pronuclei of one cell bovine embryos produced by in vitro fertilization. After microinjection, embryos were cultured in vitro for 6 or 7 days. Twenty embryos reaching to blastocysts were transferred to 10 beef recipients, each receiving two embryos. Recipients were diagnosed for pregnancy by rectal palpation at 76 days after embryo transfer. One of them was pregnant to term and produced a female calf weighing 21 kg at 280 days following embryo transfer. DNA was extracted from umbilical cord tissue and blood of calf born for confirming gene insertion. As determined by Southern hybridization, the transgene was not found.

• Journal of Powder Materials
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• v.1 no.2
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• pp.198-207
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• 1994

In order to find an optimal friction-welding condition for Ni-base ODS alloy (MA 754) produced by mechanical alloying, joint experiments were performed with various conditions of friction pressures (50~500 MPa), friction times (1~5 sec) and upset pressures (50~600 MPa). The optimal friction pressure and upset pressure must be above 400 MPa and 500 MPa, respectively, which are determined by tensile strengths and fracture features of as-welded joints. A maximum stress설h of 975 MPa could be obtained under these pressure conditions at friction time of 2 sec. Microstructural features of bonded interface by optical microscope and SEM revealed that the interface regions of all specimens are consisted with three distinct regions and defects such as voids, cracks and wavy interfaces exist in the joints produced under not-optimized conditions. EDS results showed that these defects include oxides composed with elements of Al, Y and Ti. The hardness on the bonded interface was higher than in the base metal region. Specimens fractured in bonded interface region had lower strength values compared to those fractured in base metal region. Surfaces of the former showed a typical intergranular fracture.

• Journal of The Korean Astronomical Society
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• v.26 no.1
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• pp.79-81
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• 1993

We calculated the solar monopole abundance limit by comparing the observed solar neutrino flux and the calculation of non-fusion solar neutrino flux produced by Rubakov process in the solar core. We included the produced meson's enhancement effects by the surrounding ions in the solar core. We find that the monopole number $N_M<1.9\times10^{20}(1mb/{\sigma}0)$, where ${\sigma}0$ is the characteristic proton decay cross section of Rubakov process. This is similar or stronger than strong limits obtained from neutron star's luminosity.

• Archives of Pharmacal Research
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• v.23 no.5
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• pp.531-534
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• 2000

Nitric oxide (NO), products of activated macrophages, have a great impact on the regulation of cytokine production. The role of NO in non-specific host cells is commonly accepted. On the contrary, its role as an immuno-regulatory molecule is still controversial. In this study, we have investigated the effect of NO on the production of cytokines from murine splenocytes and macrophages. S-nitroso-L-glutathione inhibited the release of both interferone-$\gamma$ and interleukin-2 produced by Th1 cells and tumor necrosis factor-$\alpha$ and interleukin-1$\beta$ produced by macrophages, but did not affect the release of interleukin-4 and interleukin-10 produced by Th2 cells. These results suggest that NO exerts a down-regulatory effect on the secretion of cytokines from Th1 cells and macrophages which are implicated in immune response. Thus, NO may have an important role as an immune-modulatory as well as effector molecule in the immune system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.117-124
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• 2004

The mixing enhancement is one of the most important problems for the development of scramjet engines. The influence of the streamwise vortices produced by a ramp in a unheated supersonic flow on the mixing of twin jets injected from its base was experimentally investigated. Nominal Mach number of the main airstream and of the twin jets at the nozzle exits were 2.35 and 2.0, respectively. Three dimensional velocity distributions near the ramp with and without injection were measured by Particle Image Velocimetry (PIV). A pair of counter rotating streamwise vortices could be seen behind the injector without injection. On the other hand, two pairs of streamwise vortices could be seen with injection. The outer one had the same direction as the vortex pair produced by the ramp, but they were stronger than those produced by the ramp. The inner ones had the opposite directions to the outer ones. It is considered that these vortices enhance the mixing near the injector.