• 한국전자파학회논문지
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• 제21권6호
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• pp.642-650
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• 2010

본 논문에서는 주어진 임무에 대한 저궤도 위성용 TT&C(Telemetry Tracking and Command system) 안테나를 설계하기 위해 먼저 링크 버짓을 통해 요구 성능을 도출하고, 이에 따라 안테나를 설계한다. 전제된 임무 궤도는 태양 동기 원형 궤도이며, 지구 및 우주 관측 임무를 수행한다. TT&C 시스템의 링크 버짓을 설계하여 최소 3dB 마진을 가지기 위한 안테나의 요구 이득과 빔 폭을 도출하였으며, 이렇게 설계된 위성용 TT&C 안테나는 넓은 빔 폭을 가지는 원형 편파 턴스타일 안테나이다. 한편, 안테나를 위성에 설치하였을 때 방사 특성의 변화를 확인하였으며, 최적의 설치 위치를 제안하였다. 또한 설계된 턴스타일 안테나의 전기적 성능을 바탕으로 TT&C링크 모의실험을 통해 임무 중 안테나의 성능을 검증한다.

• 신재생에너지
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• 제9권4호
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• pp.40-50
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• 2013

This study was performed to investigate the potential of torrefied tulip tree (TT) for the production of pellets. For this purpose, chemical composition and fuel characteristics of torrefied TT were examined. In addition, pellets were fabricated by using sawdust of torrefied TT chip, and durability of the pellet was measured. Lignin content of torrefied TT was higher than that of non-torrefied TT, and increased with the increases of torrefaction temperature and time. Fuel characteristics of torrefied TT were affected by torrefied conditions, and the characteristics were influenced more by torrefaction temperature than by torrefaction time. Higher heating value (HHV) and ash content (AC) of torrefied tulip tree increased with increasing torrefaction temperature, and the values were much higher than HHV and AC values of non-torrefied TT. Durability of pellets fabricated with $230^{\circ}C$- and $250^{\circ}C$-torrefied TT was higher than that of $270^{\circ}C$-torrefied TT, and the value exceeded the minimum requirement (-97.50%) of the 1st-grade pellet standard designated by Korea Forest Research Institute. Based on the results, torrefaction treatment of $250^{\circ}C/50min$ to TT might be a optimal condition for the production of TT pellets considering the mass balance and fuel characteristics of TT as well as the durability of the pellets. Thus, it is confirmed that torrefied TT can be used as a raw material for the production of bio-pellets.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.37-40
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• 1999

ETRI has successfully completed and delivered to KARI the KOMPSAT Mission Control System. This system was designed to work in the conventional TT&C modulation scheme with the pre-assigned frequencies. As a way to accelerate in catching up with future TT&C technology evolutions, a preliminary study needs to be carried out to prepare for the development of a spread spectrum applicable to TT&C. A brief study was carried out to review some points to be considered in designing and implementing spread spectrum schemes to the ground TT&C system intended for a LEO spacecraft. Also a simulation and link design revisit was performed to see the operational and technical benefits with the KOMPSAT TT&C parameters. An experiment concept is proposed to test as many functions at a time once the prototype is developed. In this configuration, a ground-model TT&C transponder is connected via LAN to the ETRI-developed KOMPSAT S/W simulator and linked to the KOMPSAT TM/TC processing s/w via spread spectrum signals through a GEO satellite bent-pipe link. A satellite data relay link simulation could be carried out in this configuration.

• Asian Pacific Journal of Cancer Prevention
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• 제15권3호
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• pp.1345-1349
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• 2014

Although many epidemiologic studies investigated the methylenetetrahydrofolate reductase (MTHFR) polymorphisms and their associations with esophageal cancer, definite conclusions could not be drawn. To clarify the effects of MTHFR polymorphisms on the risk of esophageal cancer, a meta-analysis was here performed in Chinese populations. A total of 16 studies including 3,040 cases and 4,127 controls were involved in this metaanalysis. Overall, significant associations were found between the MTHFR C677T polymorphism and esophageal cancer risk when all studies in Chinese populations were pooled into the meta-analysis (T vs. C, OR = 1.19, 95% CI = 1.06-1.34; TT vs. CC, OR = 1.35, 95% CI = 1.07-1.70; TT+ CT vs. CC, OR = 1.29, 95% CI = 1.08-1.54; TT vs. CC + CT, OR = 1.19, 95% CI = 1.03-1.37). In subgroup analyses stratified by ethnicity and source of controls, the same results were found in Kazakh (TT vs. CC, OR = 1.38, 95% CI = 1.02-1.87; TT + CT vs. CC, OR = 1.50, 95% CI = 1.03-2.18), in not stated populations (T vs. C, OR = 1.24, 95% CI = 1.08-1.42; TT vs. CC, OR = 1.47, 95% CI = 1.10-1.96; TT + CT vs. CC, OR = 1.30, 95% CI = 1.05-1.60; TT vs. CC + CT, OR = 1.32, 95% CI = 1.12-1.56), and in hospital-based studies (T vs. C, OR = 1.34, 95% CI = 1.19-1.51; TT vs. CC, OR = 1.81, 95% CI = 1.37-2.39; TT + CT vs. CC, OR = 1.51, 95% CI = 1.26-1.83; and TT vs. CC + CT, OR = 1.39, 95% CI = 1.13-1.70). In conclusion, this meta-analysis provides evidence that the MTHFR C677T polymorphism contributes to esophageal cancer development in Chinese populations.

• Journal of Astronomy and Space Sciences
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• 제14권1호
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• pp.158-165
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• 1997

The Sun interference event predictions for the KOMPSAT TT&C station were performed to analyze the frequency of the event and the impact on the TT&C link. The KOMPSAT orbit was propagated including only J2 geopotential term for maintaining the Sun-synchronism and no other perturbations were included. Local time of ascending node of the KOMPSAT satellite was set to 10h50m00s. The TT&C station was assumed to locate in Taejon and have 9 meter antenna for S-band link. One year of simulation from 1999/07/01 were performed out of 3 year of mission lifetime of KOMPSAT satellite. Total four times of Sun interference events were occurred during 1 year of simulation and those lasted about 50 seconds altogether. The C/N degradation of the TT&C system was calculated about 4dB. The Sun interference event of 50 seconds of year are 0.0076 percents of the S-band contact time when the 30 minute of contact time is assumed in a day.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.36.2-36.2
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• 2008

This paper presents the impact of Japanese radio source on the S-Band communication between KOMPSAT-2 satellite and TT&C ground system. Major specifications such as transmitting EIRP (Effective Isotropic Radiated Power) and location of Japanese terrestrial station were informed from Radio Research Laboratory in Korea Communication Commission. To estimate path loss in S-Band, the distance between Japanese station and TT&C ground system was obtained by using COTS (Commercial Off-The-Shelf) software. After that the signal strength of Japanese radio source placed at the TT&C ground system was calculated from link parameters such as transmitting EIRP, path loss, and receiving antenna gain. Consequently, this paper shows that the degradation caused by Japanese radio source is acceptable to TT&C ground system for satellite operation.

• Journal of Microbiology and Biotechnology
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• 제22권10호
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• pp.1401-1405
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• 2012

A thermotolerant Saccharomyces cerevisiae mutant strain, TT6, was constructed after multi-parental hybridization of five mutant strains obtained by UV or NTG treatment of the original strain, S. cerevisiae KV1. When incubated at $40^{\circ}C$ in YPD broth, TT6 began to grow exponentially in 10 h, but KV1 did not show any noticeable growth even after 22 h. The thermotolerant growth of TT6 was confirmed by serial dilution assay at $42^{\circ}C$; TT6 grew at a cell concentration ($10^{-5}$) 10,000 times lower than that of KV1 ($10^{-1}$). Whereas ethanol production from YP containing 23% (w/v) glucose by KV1 decreased with increasing temperature from $30^{\circ}C$ to $36^{\circ}C$, ethanol production by TT6 did not decrease at temperatures up to $37^{\circ}C$. When TT6 was tested for ethanol production at $36^{\circ}C$ by simultaneous saccharification and fermentation (SSF) from 23% corn, 24 h of fermentation time or 50% of the glucoamylase dose was saved when compared with KV1 at $30^{\circ}C$. The ethanol yield from corn by SSF with TT6 at $36^{\circ}C$ was 91.7% of the theoretical yield, whereas that of KV1 at $30^{\circ}C$ was 90.6%.

• 디지털융복합연구
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• 제11권1호
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• pp.299-308
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• 2013

TCDD 독성이 유발된 흰쥐 혈액의 생화학적 지표에 미치는 상엽 물추출물 (MLE)의 효과를 조사하였고 통계자료는 일원분산분석과 Scheffe의 사후검증을 하였다. TCDD 투여 시 감소했던 백혈구와 혈소판의 수가 MLE투여로 급격하게 회복(p<0.01)되어 면역기능 개선효과가 있었다. TT에 의해 감소했던 혈중 칼슘 및 마그네슘의 농도는 MLE 투여 시 유의하게 증가(p<0.01)하였으나 인의 농도는 TT군에 비하여 MLE군이 유의하게 감소(p<0.01)하였다. 신장 기능과 관련된 creatinine 및 blood urea nitrogen은 TT군과 MLE군 사이에 유의성은 없었으며, 요산은 TT군과 MLE군 모두에서 감소하였다. 한편 TT에 의해 증가했던 glucose 농도, amylase 및 lipase의 효소 활성도는 MLE 투여시 유의하게 감소(p<0.01)하여 혈당상승 억제효과가 있었다. Total protein, ${\gamma}$-GTP 활성은 TT와 MLE의 영향을 거의 받지 않았으나 TT에 의해 증가했던 AST, ALT 및 ALP의 활성도는 MLE 투여 시 모두 유의하게 감소(p<0.01)하여 간기능 개선의 효과가 있었다. 한편 Total cholesterol, triglyceride와 LDL-cholesterol의 경우 TT에 의해 유발된 고지혈 증상이 MLE 투여 시 유의하게 감소(p<0.01)하여 항고지혈 효과가 있었으며 HDL-cholesterol은 TT군과 MLE군 모두에서 증가하였다. 이와 같이 MLE는 TCDD독성이 유발된 흰쥐에서 독성을 완화시켜 주는 작용이 있음을 알 수 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권20호
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• pp.8725-8734
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• 2014

The transforming growth factor-${\beta}1$ (TGF-${\beta}1$) gene 29 T/C polymorphism is thought to be associated with breast cancer risk. However, reports are largely conflicting and underpowered. We therefore conducted a meta-analysis of all available case-control studies relating the TGF-${\beta}1$ 29T/C polymorphism to the risk of developing breast cancer by including a total of 31 articles involving 24,021 cases and 31,820 controls. Pooled ORs were generated for the allele contrasts, with additive genetic, dominant genetic and recessive genetic models. Subgroup analysis was also performed by ethnicity for the TGF-${\beta}1$ 29T/C polymorphism. No association was found in the overall analysis (C vs T: OR=1.028, 95% CI=0.949-1.114, p-value 0.500; CC vs TC: OR= 1.022, 95% CI=0.963-1.085, p-value 0.478; CC vs TT: OR= 1.054, 95% CI=0.898-1.236, p-value 0.522; CC vs TT+ TC: OR= 1.031, 95% CI=0.946-1.124, p-value 0.482; TT vs CC+TC: OR= 0.945, 95% CI=0.827-1.080, p-value 0.403). Similarly, in the subgroup analysis by ethnicity, no association was found in Caucasian (C vs T: OR= 1.041, 95% CI=0.932-1.162, p-value 0.475; CC vs TC: OR= 1.031, 95% CI=0.951-1.118, p-value 0.464; CC vs TT: OR= 1.081, 95% CI=0.865-1.351, p-value 0.493; CC vs TT+TC: OR= 1.047, 95% CI=0.929-1.180, p-value 0.453; TT vs CC+TC: OR= 0.929, 95% CI=0.775-1.114, p-value 0.429;) and Asian populations (C vs T: OR= 1.004, 95% CI=0.908-1.111, p-value 0.931; CC vs TC: OR= 0.991, 95% CI=0.896-1.097, p-value 0.865; CC vs TT: OR= 1.015, 95% CI=0.848-1.214, p-value 0.871; CC vs TT+TC: OR= 1.000, 95% CI=0.909-1.101, p-value 0.994; TT vs CC+TC: OR= 0.967, 95% CI=0.808-1.159, p-value 0.720;). No evidence of publication bias was detected during the analysis. No significant association with breast cancer risk was demonstrated overall or on subgroup (Caucasian and Asian) analysis. It can be concluded that TGF-${\beta}1$ 29T/C polymorphism does not play a role in breast cancer susceptibility in overall or ethnicity-specific manner.

• 조명전기설비학회논문지
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• 제24권6호
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• pp.67-74
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• 2010

국내의 저압수용가 대부분은 한국전력공사의 TN-C접지방식으로부터 공급받고 있으나 부하설비는 TT 접지방식을 위주로 한 전기설비기술기준에 따라 시설되어 있다. 본 연구에서는 정보기술설비를 뇌서지로부터 보호할 수 있는 적절한 전원계통접지방식을 제안하기 위해서 TT, TN계통의 뇌서지에 대한 보호성능을 연구하였다. 그 결과, 뇌서지가 배전계통의 중성선에 입사한 때 TT계통의 기기접지단자와 전원선의 중성점 사이에 높은 전위차가 발생하였으며, 예민한 컴퓨터설비가 손상될 위험성이 있으므로 TT계통은 적합하지 않다. 뇌서지로부터 저압 설비를 보호하기 위해서는 등전위본딩이 중요한 요건이며, TN계통이 중성선을 통하여 입사하는 뇌서지의 저감에 가장 우수하였으며, 수용가 인입구에서의 추가접지도 바람직한 방법이다.