• Korean Journal of Materials Research
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• v.7 no.10
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• pp.872-876
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• 1997

(1-x)CaTi $O_{3}$-xLa(Z $n_{1}$2/ $Ti_{1}$2/) $O_{3}$의 마이크로 유전특성을 조사하였다. x가 증가함에 따라 비유전율과 공진주파수의 온도계수는 감소하였으며, Qㆍ $f_{0}$는 증가하였다. 그 결과 x=0.5인 (C $a_{0.5}$L $a_{0.5}$)( $Ti_{0.75}$Z $n_{0.25}$) $O_{3}$의 조성에서 $\varepsilon$$_{r}$=51, Qㆍ $f_{0}$=38,000 (at 7 GHz), $\tau$$_{f}$=+5ppm/$^{\circ}C$의 유전특성이 나타났다. (C $a_{0.5}$L $a_{0.5}$)( $Ti_{0.75}$Z $n_{0.25}$) $O_{3}$조성의 소결온도를 저하시키기 위하여 B $i_{2}$ $O_{3}$를 주조성으로한 소결체를 첨가하여 소결 및 유전특성을 조사하였다. 1wt% 0.76B $i_{2}$ $O_{3}$-0.24NiO가 첨가된 경우 소결온도는 15$0^{\circ}C$ 낮아졌으며, 비유전율 ($\varepsilon$$_{r}$), 공진주파수의 온도계수($\tau$$_{f}$), Qㆍ $f_{0}$가 각각 50+5ppm/$^{\circ}C$, 35,000인 마이크로파 유전특성이 얻어졌다. 또한 3wt%의 0.76B $i_{2}$ $O_{3}$-0.24NiO가 첨가된 경우 소결온도는 20$0^{\circ}C$ 저하되었고, 비유전율 ($\varepsilon$$_{r}$)과 공진주파수의 온도계수 ($\tau$$_{f}$)는 변하기 않았으나, Qㆍ $f_{0}$값이 38,000에서 25,000으로 저하되었다. 25,000으로 저하되었다.되었다.되었다.되었다.

• Journal of the Korean association of regional geographers
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• v.10 no.1
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• pp.67-82
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• 2004

There is a general agreement that the global social-economic system is undergoing fundamental changes, which can be explained in terms of the transformation of production system from the Fordism to Post-Fordism since the 1980s. These fundamental changes have resulted in the 'new urbanization' process in the most of large cities in the developed countries. The aim of this paper is to identify the 'new urbanization' process in a large city in Korea that is, Daejon. For the propose, this paper tries to examine and conceptualize empirically the changes of economic, political, social-cultural, and spatial aspects of Daejon metropolis in the respect of 'new urbanization'. The major findings of this essay are summarized as follows. First of all, Daejon economy has experienced new changes, that is the development of service economy and high tech industry. But the old industry still remain important in the urban economy. Secondly, in the political aspect, new civil movements flourish in the city, while the political power of Jaminlyeon, a pro-conservative and narrow-regionalism party, once dominated this region, has decreased its influence. Thirdly. the original CBD of Daejon has been declined while new (sub-)CBBs have emerging in Daejon spatial structures. In conclusion, we can find some clues of the new urbanization process in Daejon, but this process is still quite slow and somewhat different from those of large cities of the developed countries.

• Korean Journal of Medicinal Crop Science
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• v.28 no.1
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• pp.9-20
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• 2020

Background: Although a number of Panax ginseng cultivars have been developed by Korean researchers in recent years, there has been insufficient analysis of their beneficial properties. In this study, we sought to identify useful ginseng varieties as functional materials. Methods and Results: We evaluated effects of root extracts of 10 ginseng cultivars (Cheongsun; CS, Chunpoong; CP, Gopoong; GP, Gumpoong; GMP, K1, Sunhyang; SH, Sunone; SO, Sunpoong; SP, Sunun; SU and Yunpoong; YP) against the inhibitory effects of nitric oxide (NO) and reactive oxygen species (ROS) production in mouse brain microglial BV2 cells, as well as the binding of N-methyl-D-aspartate receptor (NMDAR), a marker related to memory. Ginsenosides, such as 20 (S)-protopanaxadiols (PPDs), including ginsenoside-Rb1, -Rb2, -Rb3, -Rc, -Rd, and - Rg3 and 20 (S)-protopanaxatriols (PPTs) including -Re, -Rg1, and -Rg2 were analyzed by HPLC. We observed that the cultivar GMP showed the highest inhibitory effect (60.8%) against NO production at 20 ㎍/㎖. Those cultivars showing the significantly highest inhibition effects against ROS at 20 ㎍/㎖ were K1 (57.3%), SP (54.5%), YP (53.1%), CP (51.7%), CS (50.9%) and SH (49.6%). At 50 ㎍/㎖, K1 showed the most potent inhibitory effect (51.2%) on NMDAR binding. The total phenol content of SH (1.89 mg/g) and K1 (1.73 mg/g) were higher than those of the other cultivars, whereas in terms of PD/PT ratios, the values of CP (0.98), K1 (1.05) and SO (1.05) were lower than those of the other cultivars. On the basis of correlation coefficient (0.7064) between NMDAR inhibition and ONOO^- scavenging activity. Conclusions: The findings of this study indicate that the cultivars K1 and SH could be useful ginseng resources as functional materials with favorable cognition-improving and antioxidative properties.

• Progress in Medical Physics
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• v.9 no.1
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• pp.55-64
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• 1998

In recent, the demand of development of the high dose rate brachytherapy source increased for substitute for Co-60 source by iridium source, since the supplying Co-60 source is very depressed and the high dose rate brachytherapy sources are entirely imported from the abroad. This study investigated the exposure rates and isotropic dose distributions for the Ir-192 source produced from $\^$191/Ir(n,r)$\^$192/Ir by nuclear reactor in Korea Atomic Energy Research Institute. The activity of source was obtained an 1.012 Ci (the initial activity without encapsulation was 2,87Ci) by measurement with encapsuled stainless steel. The exposure rate of provided Ir-192 source was determined on 6.36 ${\pm}$ 0.147 Rm$^2$/h-GBq (2.350 ${\pm}$ 0.054 Rcm$^2$/mCi-hr) within ${\pm}$ 2.2% discrepancy with IC-10 ion chamber (0.14 cc) which was mounted on the acrylic jig to 5, 10 and 20 cm from the center of source. The calculated doses with 22 most significant spectrum lines were corrected with intrinsic efficiency of the germanium detector were compared to measured exposure dose rates within ${\pm}$3.8 % discrepancy. The authors confirmed the high dose rate Ir-192 source could be replaced the long decayed Co-60 source via investigation of the isotropic dose distributions in lateral, source axis and diagonal direction of source center are very closed to within 3% uncertainties. Especially, this exposure rate constant and isotropic dose distribution will be fundamental to build the high dose rate source and develop the computed therapy planning system.

• Journal of the Korean Electrochemical Society
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• v.11 no.4
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• pp.284-288
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• 2008

Sn-thin film as high capacitive anode for thin film lithium-ion battery was prepared by organic-electrolyte electroplating using Sn(II) acetate. Electrolytic solution including $Li^+$ and $Sn^{2+}$ had 3 reduction peaks at cyclic voltammogram. Current peak at $2.0{\sim}2.5\;V$ region correspond to the electroplating of Sn on Ni substrate. This potential value is lower than 2.91 V vs. $Li^+/Li^{\circ}$, of the standard reduction potential of $Sn^{2+}$ under aqueous media. It is the result of high overpotential caused by high resistive organic electrolytic solution and low $Sn^{2+}$ concentration. Physical and electrochemical properties were evaluated using by XRD, FE-SEM, cyclic voltammogram and galvanostatic charge-discharge test. Crystallinity of electroplated Sn-anode on a Ni substrate could be increased through heat treatment at $150^{\circ}C$ for 2 h. Cyclic voltammogram shows reversible electrochemical reaction of reduction(alloying) and oxidation(de-alloying) at 0.25 V and 0.75 V, respectively. Thickness of Sn-thin film, which was calculated based on electrochemical capacity, was $7.35{\mu}m$. And reversible capacity of this cell was $400{\mu}Ah/cm^2$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.9
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• pp.886-894
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• 2014

A wideband bow-tie antenna fed by wideband microstrip-coplanar stripline(CPS) balun and band notch structures that can be applied to bow-tie antenna are proposed in this paper. In order to increase bandwidth, bow-tie radiators are reshaped so that the surface current flows continuously, and wideband impedance matching is achieved by adjusting strip width and spacing of CPS feeding line. The VSWR is measured as 2:1 over the wide frequency range of 2.3~12 GHz. The fabricated antenna size is $60mm{\times}60mm$. In order to achieve the band-notch function at WLAN(5.8 GHz), ${\lambda}/4$ folded-slits located ${\lambda}/4$ away from feeding point are utilized. To minimize the slit size, folded-slit type is adopted. The measured VSWR is 7:1 and gain attenuation is 14 dB at 5.8 GHz.

• Clinical and Experimental Reproductive Medicine
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• v.31 no.2
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• pp.111-117
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• 2004

Objectives: To investigate the effect of LH receptor in folliculogenesis, we confirm the expression level of LH receptor (LH-R) mRNA in human granulosa cells (GCs) and its expression levels were analyzed by comparison to embryo developmental rate and pregnancy rate. Materials and Methods: GCs were obtained at the time of oocyte retrieval from the patients undergoing IVF-ET program. The patients were divided into two groups: Group I (n=20) is poor responder (retrieved oocyte(s)$\leq$3ea), Group II (n=80) is normal responder (retrieved oocytes>3ea). After the extraction of total RNA, semiquantitative RT-PCR was performed and the expression level of LH-R mRNA was normalized by $\beta$-actin. Statistical analysis was performed by using $X^2$ test, Student's t-test and Pearson correlation. Results: In Group II, the relative values of LH-R mRNA (0.680 vs. 0.463, p<0.005) and pregnancy rate (54.7% vs. 23.1%, p<0.05) were significantly higher than in Group I. Number of retrieved oocyte(s) was gradually increased when the expression of LH-R mRNA was increased (p<0.05). But the quality of retrieved oocyte and transferred embryo were not related with the expression of LH-R mRNA. When the pregnancy rate was compared with FSH only group and FSH combined with hMG group in the ovarian stimulation protocol, FSH combined with hMG group was significantly higher than FSH only group in Group I (37.5% vs. 0%), and the expression of LH-R mRNA was significantly higher in hMG combined group than FSH only group (p<0.05). Conclusion: Expression level of LH-R mRNA has important role in ovarian function related with the response to gonadotrophin in human folliculogenesis. Furthermore these data might provide the evidence that additional use of hMG is helpful to poor responders.

• Korean Journal of Medicinal Crop Science
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• v.12 no.1
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• pp.24-30
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• 2004

The immune activities of Ganoderma lucidum Mycelium added garlic extracts (GAM), Ganoderma lucidum Mycelium (GM), garlic extracts (GS) and standard $({\beta}-glucan)$ were compared. GAM enhanced the growth of human immune T cell up to $1.25{\sim}1.46$ times, compared to control group. GAM showed relatively lower cytotoxicity in using normal human lung cell, while GAM showed the most potent inhibitory effect on the human lung carcinoma, compared to GM and GS. The selectivity of GAM was also higher than that of GM and GS. GAM increased the secretion of cytokines, IL-6 and TNF- from human B cell as well as the growth of human immune cells. It can imply that GAM has higher immune activity than GM or GS.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.6
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• pp.21-30
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• 2013

As increasing number of large-size earthquake, the social interest of seismic retrofitting of RC structure is growing. Especially, the RC columns that are not reflected seismic design can not resist lateral loads by the earthquake. The brittle fracture of Non-seismic designed columns lead to full collapse of the building. Thus, the emergency columns reinforcement method is needed. That have a fast construction time, do not cause damage to the column. In the past, cross-sectional expansion method, a steel plate reinforcing method is applied mainly, but in recent years, carbon fiber sheet taking advantage of FRP (Fiber Reinforced Polymer) is widely used. In this study, retrofitting effect of seismic performance of FRP seismic reinforcement, which is possible to emergency construction, was examined. Reinforced concrete specimens were constructed to experimental study. The seismic performence of specimes retrifitted with FRP seismic reinforcement were evaluated. As a result, the seismic performance of specimen reinforced with FRP seismic reinforcement has been improved.

• KSBB Journal
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• v.24 no.2
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• pp.163-169
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• 2009

Lovastatin (also known as Mevinolin, Mevacor, and Monacolin K), an inhibitor of the HMG-CoA reductase produced by Aspergillus terreus and other fungi, is used to reduce serum cholesterol levels in human beings. It is derived biosynthetically from two polyketides. One of these is a nonaketide that undergoes cyclization at a hexahydronaphthalene ring system, and the other is a simple diketide, 2-methylbutyrate. Two primer pairs were designed based on the amino acid sequences of lovastatin polyketide synthase and lovastatin diketide synthase for the PCR screening of lovastatin-producing strains. Among the seven selected strains, SJ-2 evidenced the highest level of lovastatin production in both liquid and solid cultures. Soybeans with SJ-2 were treated via 1 hour of heat shock at $30^{\circ}C$ for the mass production of lovastatin. The heat-treated soybeans were inoculated on rice bran and the koji extract was obtained after 15 days of incubation. It yielded the highest level of lovastatin production among the strains, and also evidenced 75% inhibition activity against HMG-CoA reductase. We developed an efficient PCR screening method for lovastatin-producing strains, using lovastatin biosynthesis genes.