• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.115-120
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• 1989

For the purpose of obtaining microorganisms which produced an extracellular pepsin inhibitor, screening test was carried out. One strain of Actinomycetes (GF 155-2) isolated from soil samples showed a high inhibitory activity against porcine pepsin. The morphological, physiological and cultural characteristics of the strain GE 155-2 on various culture media were studied according to ISP methods and Bergey's manual of determinative bacteriology (8th ed.). This Actinomycetes GE 155-2 was found to be similar to the genus Microtetraspora.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.237.1-237.1
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• 2011

Resistivity of GaN has been investigated under the influence of ion implantation. n-type, p-type and also undoped GaN has been used here. A ring shape pattern of Au was fabricated on GaN film by the photolithography technique. H, He and Ar were used for implantation. The ion implantation energy, fluence and post-implant annealing temperature varied in this research. Because of the making barrier in some selected area using ions, the resistivity changed in all the samples with the change of both fluence and energy. At room temperature, the resistivity of n-type GaN has been increased from $1.9{\times}10-2$ to $17.7{\times}10-2\;{\Omega}-cm$. This is high for He ion. But undoped and p-type GaN showed some anomalous character.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.6
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• pp.261-269
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• 2014

In order to increase the seismic safety of nuclear power plant (NPP) structures in high seismicity regions, seismic isolation techniques can be adapted to NPP structures. In this paper, the applicability of multi-step analysis of seismically isolated NPP containment structures with lead-rubber bearings (LRB) is evaluated. The floor response spectrum of NPP containment structures with equivalent linear LRB and nonlinear LRB are compared. In addition, the force-displacement relationships for equivalent linear LRB and nonlinear LRB are compared.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.10a
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• pp.45-51
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• 1996

The combined shear and compression behaviors of seismic isolation rubber bearings are analyzed using the hyperelasticity material option of the ABAQUS computer program. The purpose of the analysis is to predict the behavior of laminated rubber bearing before the several tests. Some kinds of strain energy density functions are used as constitutive law for rubber itself having the hyperelasticity. The results are compared with test data peformed in Italy The analysis results show a little different with experimental results depending on the constitutive model and the refinement of finite element. The high order form of strain energy density functions results in good agreements and the mesh refinement above two for one rubber layer is enough to get good results.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1046-1049
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• 2002

In this paper, a sub-harmonic dual-gate FET mixer for IMT-2000 base-station was designed by using single-gate FET cascode structure and driven by the second order harmonic component of LO signal. The dual-gate FET mixer has the characteristic of high conversion gain and good isolation between ports. Sub-harmonic mixing is frequently used to extend RF bandwidth for fixed LO frequency or to make LO frequency lower. Furthermore, the LO-to-RF isolation characteristic of a sub-harmonic mixer is better than that of a fundamental mixer because the frequency separation between the RE and LO frequency is large. As RF power is -30dBm and LO power is 0dBm, the designed mixer shows the -47.17dBm LO-to-RF leakage power level, 10dB conversion gain, -0.5dBm OIP3, -10.5dBm IIP3 and -1dBm 1dB gain compression point.

• Archives of Pharmacal Research
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• v.21 no.3
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• pp.344-347
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• 1998

To overcome multidrug resistance (MDR) in cancer chemotherapy, we prepared various plant extracts and searched for a component which is effective for inhibition of MDR. MDR inhibition activity was determined by measuring cytotoxicity to MDR cells using multidrug resistant human fibrocarcinoma KB V20C, which is resistant to 20 nM vincristine and expresses high level of mdr1 gene. Of various plant extracts, the MeOH extract of the root of Aconitum pseudo-laeve var. erectum was found to have potent inhibitory activity on MDR. The bioassayguided fractionation of the MeOH extract of the plant led to the isolation of an alkaloid, lycaconitine, as an active principle. And the $IC_{50}$ of lycaconitne for KB V20C cells was $74\mu{g}$/ml.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.499-504
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• 2004

The purpose of this study is to investigate a investigating of a floor-impact isolation system using damping materials in apartment buildings. The stiffness elastic modulus(k) by puls impact forces were calculated loss factor by Hilbert transforms. It is absolved that natural frequency was moved floor shock-absorbing materials and the impact force was reduced by floor panel. The slab was constructed by damping materials. As towards a result, the system showed inverse A 45dB by heavy weight-impact noise and inverse A 52dB by light-impact noise. High frequencies impact-noise can be reduced by upgrading naturial frequency of vibration and noise in the system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.189-192
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• 2001

Recently, STI process is getting attention as a necessary technology for making high density of semiconductor by devices isolation method. However, it does have various problems caused by CMP nprocess, such as torn oxide defects, nitride residues on oxide, damages of si active region, contaminations due to post-CMP cleaning, difficulty of accurate end point detection in CMP process, etc. In this work, the various defects induced by CMP process was introduced and the above mentioned problems of CMP process was examined in detail. Finally, the guideline of future CMP process was presented to reduce the effects of these defects.

• Fisheries and Aquatic Sciences
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• v.11 no.3
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• pp.172-176
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• 2008

To develop a potent strain for the production of coenzyme $Q_{10}$, a photosynthetic bacterium was isolated from silt of the Nakdong River in Korea. Using l6S-rDNA sequence analysis, the isolated strain was identified as Rhodobacter sphaeroides. A stable improvement in its $CoQ_{10}$ content was achieved by chemical mutation, upon which the content of $CoQ_{10}$(2.94 mg/g dry cell) was increased by approximately 1.9-fold, comparable to that of R. sphaeroides reported in other studies. The isolate is a potentially valuable microorganism for mass production of $CoQ_{10}$, and may provide an appropriate model for further study of economical mass production.

• Proceeding of KASS Symposium
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• 2005.05a
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• pp.227-235
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• 2005

The earthquake-resistant structural systems have to ensure the sufficient stiffness and ductility for the stability. For those purposes, recently, the performance design concept to increase the degree of absorbed energy level of structures has been proposed. One practical way of the performance design in the spatial structures is to apply the isolation system to boundary parts of roof system and sub-structure to obtain the target performance. So, it is necessary to examine the characteristics of dynamic behavior of spatial structures governed by higher modes rather than lower modes different from the cases of high rise buildings. The objectives of this paper are to develop the equivalent model to simplify the analytical processes and to investigate the dynamic behavior of roof system according to the mass and the stiffness of sub-structures as a fundamental study of performance design for the spatial structures.