• 한국수학교육학회지시리즈B:순수및응용수학
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• 제2권2호
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• pp.91-95
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• 1995

Let H be an arbitrary complex Hilbert space and let (equation omitted)(H) be the *-algebra of all bounded linear operators on H. An operator T in (equation omitted)(H) is called normal if T$\^$＊/T = TT$\^$＊/, hyponormal if T$\^$＊/T $\geq$ TT$\^$＊/, and quasi-hyponormal if T$\^$＊/(T$\^$＊/T － TT$\^$＊/)A $\geq$ 0, or equivalently ∥T$\^$＊/T$\chi$∥ $\leq$ ∥TT$\chi$∥ for all $\chi$ in H.(omitted)

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.315-318
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• 2009

Electric shock is the accident caused by the current through a person or animal's body. That is characterized by the physiological effects. In this paper, we evaluate performance of protection against electric shocks for TT and TN grounding systems which are used by a low voltage consumer nowadays. The performance of protection against electric shocks for TT grounding system is very excellent in equipotential area of the third class grounding, but the performance is poor outside the equipotential area. The performance of protection against electric shocks for TN grounding system is excellent because the potential difference is less than 50V. Accordingly, the performance of protection for TN grounding system is good as compared with that for TT grounding System.

• 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 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.

• Ocean Systems Engineering
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• 제12권1호
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• pp.1-22
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• 2022

The majority of tubular joints commonly found in offshore jacket structures are multi-planar. Investigating the effect of loaded out-of-plane braces on the values of the stress concentration factor (SCF) in offshore tubular joints has been the objective of numerous research works. However, due to the diversity of joint types and loading conditions, a number of quite important cases still exist that have not been studied thoroughly. Among them are internally ring-stiffened two-planar TT-joints subjected to axial loading. In the present research, data extracted from the stress analysis of 243 finite element (FE) models, verified against available numerical and experimental data, was used to study the effects of geometrical parameters on the chord-side SCFs in two-planar tubular TT-joints reinforced with internal ring stiffeners subjected to two types of axial loading. Parametric FE study was followed by a set of nonlinear regression analyses to develop six new SCF parametric equations for the fatigue analysis and design of axially-loaded two-planar TT-joints reinforced with internal ring stiffeners.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.845-848
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• 2005

Technology transfer (TT) has been defined as the shared responsibility between the source and the destination for ensuring that technology is accepted and at least understood by someone with the knowledge and resources to apply and/or use the technology. The adoption of TT in construction industries is necessary for economic growth to occur in developing countries such as Thailand. This process should provide numerous benefits for the host sector in areas such as increased productivity, enhancement of product quality, cost savings, improvements in market share and entry to new markets. However, there are many factors, which may impact on the TT process and its subsequent outcomes for Thai construction firms and individuals, including, the transfer environment, learning environment, transferor characteristics and transferee characteristics. The performance and interaction of these enablers will influence the degree of value added to the local construction sectors in areas such as economic advancement, knowledge advancement and project performance. This paper presents a conceptual framework for international TT that accommodates the numerous factors believed to impact on the processes effectiveness. Through a Pilot Study, where 27 industry professionals from Thailand were interviewed, the significant factors which impact on the TT process have been identified along with the strength of interrelationship between individual and groups of factors. Future research seeks to target a greater sample of respondents with the view to validate the conceptual model and apply it on a number of large Thai projects where international TT was incorporated into the project agreement.

• The Korean Journal of Physiology and Pharmacology
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• 제17권4호
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• pp.259-265
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• 2013

The anti-apoptotic effect of (-)-epigallocatechin-3-gallate (EGCG) during unilateral testicular torsion and detorsion (TT/D) was established in our previous study. In mice, the smallest inhibitor of apoptosis, survivin, is alternatively spliced into three variants, each suggested to have a unique function. Here, we assessed how EGCG exerts its protective effect through the expression of the different survivin splice variants and determined its effect on the morphology of the seminiferous tubules during TT/D. Three mouse groups were used: sham, TT/D+vehicle and TT/D treated with EGCG. The expression of the survivin variants (140 and 40) and other apoptosis genes (p53, Bax and Bcl-2) was measured with semi-quantitative RT-PCR. Histological analysis was performed to assess DNA fragmentation, damage to spermatogenesis and morphometric changes in the seminiferous tubules. In the TT/D+vehicle group, survivin 140 expression was markedly decreased, whereas survivin 40 expression was not significantly different. In parallel, there was an increase in the mRNA level of p53 and the Bax to Bcl-2 ratio in support of apoptosis induction. Histological analyses revealed increased DNA fragmentation and increased damage to spermatogenesis associated with decreased seminiferous tubular diameter and decreased germinal epithelial cell thickness in the TT/D+vehicle group. These changes were reversed to almost sham levels upon EGCG treatment. Our data indicate that EGCG protects the testis from TT/D-induced damage by protecting the morphology of the seminiferous tubules and modulating survivin 140 expression.

• Safety and Health at Work
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• 제8권2호
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• pp.220-225
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• 2017

Background: Benzene is a known occupational and environmental pollutant. Its urinary metabolite trans, trans-muconic acid (tt-MA) has been introduced by some environmental and occupational health regulatory associations as a biological index for the assessment of benzene exposure; however, recently, doubts have been raised about the specificity of tt-MA for low-level benzene exposures. In the present study, we investigated the association between urinary levels of tt-MA and inhalational exposure to benzene in different exposure groups. Methods: Benzene exposure was assessed by personal air sampling. Collected benzene on charcoal tube was extracted by carbon disulfide and determined by a gas chromatograph (gas chromatography with a flame ionization detector). Urinary tt-MA was extracted by a strong anion-exchange column and determined with high-performance liquid chromatography-UV. Results: Urinary levels of tt-MA in intensive benzene exposure groups (chemical workers and police officers) were significantly higher than other groups (urban and rural residents), but its levels in the last two groups with significant different exposure levels (mean = 0.081 ppm and 0.019 ppm, respectively) showed no significant difference (mean = $388{\mu}g/g$ creatinine and $282{\mu}g/g$, respectively; p < 0.05). Before work shift, urine samples of workers and police officers showed a high amount of tt-MA and its levels in rural residents' samples were not zero. Conclusion: Our results suggest that tt-MA may not be a reliable biomarker for monitoring low-level (below 0.5 ppm) benzene exposures.

• Archives of Plastic Surgery
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• 제47권3호
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• pp.242-249
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• 2020

Background The Exoscope is a novel high-definition digital camera system. There is limited evidence signifying the use of exoscopic devices in microsurgery. This trial objectively assesses the effects of the use of the Exoscope as an alternative to the standard operating microscope (OM) on the performance of experts in a simulated microvascular anastomosis. Methods Modus V Exoscope and OM were used by expert microsurgeons to perform standardized tasks. Hand-motion analyzer measured the total pathlength (TP), total movements (TM), total time (TT), and quality of end-product anastomosis. A clinical margin of TT was performed to prove non-inferiority. An expert performed consecutive microvascular anastomoses to provide the exoscopic learning curve until reached plateau in TT. Results Ten micro sutures and 10 anastomoses were performed. Analysis demonstrated statistically significant differences in performing micro sutures for TP, TM, and TT. There was statistical significance in TM and TT, however, marginal non-significant difference in TP regarding microvascular anastomoses performance. The intimal suture line analysis demonstrated no statistically significant differences. Non-inferiority results based on clinical inferiority margin (Δ) of TT=10 minutes demonstrated an absolute difference of 0.07 minutes between OM and Exoscope cohorts. A 51%, 58%, and 46% improvement or reduction was achieved in TT, TM, TP, respectively, during the exoscopic microvascular anastomosis learning curve. Conclusions This study demonstrated that experts' Exoscope anastomoses appear non-inferior to the OM anastomoses. Exoscopic microvascular anastomosis was more time consuming but end-product (patency) in not clinically inferior. Experts' "warm-up" learning curve is steep but swift and may prove to reach clinical equality.

• 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%.