• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.642-650
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• 2010

In this paper, we study a TT&C link to obtain a required specifications of TT&C(Telemetry Tracking and Command system) antenna for an LEO(Low Earth Orbit) satellite. The premised mission orbit is the sun-synchronized and circular orbit and it performs earth-space observations. We design minimum TT&C link-budget to obtain required antenna beamwidth and gain. The proposed turnstile antenna provides wide beamwidth and circular polarization. We suggested the attaching position that shows the most effective results by confirming the variation of antenna performance when the proposed antenna is adapted to satellite's various positions. Also we proved the proposed antenna's ability while it is performing the mission through the orbit simulation based on the electrical performance of the proposed turnstile antenna.

• New & Renewable Energy
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• v.9 no.4
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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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• 1999.10a
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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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• v.15 no.3
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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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• v.14 no.1
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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.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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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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• v.22 no.10
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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%.

• Journal of Digital Convergence
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• v.11 no.1
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• pp.299-308
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• 2013

We investigated the effect of mulberry leaf extract (MLE) on blood biochemical parameters of white rats induced TCDD toxicity. Data were analyzed by One-way ANOVA and Post-Hoc Test. The numbers of leukocyte and platelet decreased by TCDD were increased dramatically after treated MLE (p<0.01). The concentration of calcium and magnesium decreased by TT were increased by MLE and shown a statistical significance (p<0.01) but the concentration of phosphorus increased by TT was decreased by MLE. In the test of parameters related to renal function, only the concentration of uric acid in the MLE group was decreased than it in TT group and shown a statistical significance (p<0.01). Also the concentration of blood glucose and the activity of amylase and lipase increased by TT were decreased after treated MLE and shown a statistical significance (p<0.01), and MLE had an control effect for elevating blood glucose. In the test of parameters related to liver function, the acticity of AST, ALT and ALP increased by TT was decreased after treated MLE and shown a statistical significance (p<0.01), and MLE had an improving effect for liver function. In the case of total cholesterol (T,cho), triglyceride( TG), LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) related to lipid metabolism, the amount of T,cho, TG, LDL-C increased by TT were decreased after treated MLE and shown a statistical significance (p<0.01), and MLE had an ability of anti-hyperlipidemia. From these results, we concluded that MLE could mollified TCDD toxicity in white rats exposed to TCDD.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.67-74
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• 2010

Most of domestic low-voltage consumers are supplied from the TN-C system of KEPCO, but their load installations have established according to the national statutory standard for electrical installations based on the TT system. In this work, to propose the proper system earthing arrangements of ensuring the protection of information-technology equipment against lightning surges, the protection performance of TT and TN systems against lightning surges was investigated. As a result, when lightning surge was injected to the neutral line of distribution system, the potential difference between the equipment earth terminal and neutral point of low-voltage mains in a TT system was significantly raised. The TT system is not advised due to the risk of damage to the sensitive computer equipment. Main equipotential bonding is an important requirement for protection of low-voltage installations against lightning surges. The TN system provides the best means to reduce the incoming lightning surges through the neutral line of low-voltage service systems. In addition, It is highly recommended to install the additional earthing at the service position of low-voltage consumers.