• ALGAE
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• 제25권4호
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• pp.187-195
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• 2010

The genus Rosenvingea is well known in the tropics. Four species have been reported from Pacific Mexico: R. floridana, R. antillarum, R. intricata and R. sanctae-crucis. We collected a plant (Boca del Cielo, Chiapas) that we identified as Rosenvingea orientalis, a species not previously reported from Pacific Mexico. We were able to characterize the life cycle of this species for the first time in laboratory culture. It reproduced exclusively by plurilocular sporangia (plurangia). The mature plants were up to 6 cm long with cylindrical to compressed fronds (to 2 mm wide) with dichotomous branches in the upper half of the thallus. The medulla was hollow with 2-3 layers of large inflated colourless cells at the periphery. The cortex was comprised of 1 layer of small cells, each with a single chloroplast and pyrenoid. Linear plurangial sori with phaeophycean hairs formed along the mature fronds. Zoospore germlings developed into prostrate filamentous systems, each with a single phaeophycean hair that gave rise to a single erect shoot with multiple hairs arising near the tip. Molecular phylogeny using the psaA gene placed this isolate within the Scytosiphonaceae. It does not confirm the exact identification of R. orientalis, although its placement close to other Rosenvingea sequences was confirmed and morphological evidence supports its placement in R. orientalis. Our culture investigations indicated that it has an asexual life cycle. Further collections are needed to resolve the full generic and specific relationships of Rosenvingea and related taxa, and their reproductive patterns.

• Radiation Oncology Journal
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• 제19권2호
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• pp.146-152
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• 2001

목적 : 마우스 대뇌조직에 방사선이 조사되었을 경우 아포토시스와 세포주기의 조절작용에 어떤 영향을 미치는 지를 연구하고자 하였다. 대상 및 방법 : 8주간 성숙된 C57B1/6J 마우스의 전뇌에 코발트 방사선조사기로 25 Gy의 방사선을 단일 조사하였다. 방사선조사후 1, 2, 4, 8, 24시간 간격으로 마우스를 경추 탈구사시킨 후 뇌조직을 채취하였다. 채취한 뇌조직을 TUNEL 분석법에 의하며 아포토시스 유도 수준을 평가하였으며 Western blotting법을 이용하여 유전자 산물인 p53, Bcl-2, Bax 그리고 세포주기 조절인자인 cyclin Bl, Dl, E, cdk2, cdk4, $p34^{cdc2}$를 분석하였다. 세포주기의 변화는 유세포분석법에 의하여 분석되었다. 결과 : 아포토시스는 방사선조사후 8시간에서 최고치를 보였고 아포토시스 지수는 $24.0{\pm}0.25$ (p<0.05)였다. 세포주기에서 조절인자의 변화는 cyclin D1를 제외하고는 특이하지 않았다. 결론 : 마우스의 전뇌에 방사선을 조사한 결과 아포토시스는 대뇌의 상의하(subependyma)에서 주로 일어났으며 세포주기의 조절인자에는 영향을 미치지 않는 것으로 판명되었다.

• 한국전자파학회논문지
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• 제28권2호
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• pp.113-119
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• 2017

본 논문에서는 국내 RFID/USN 주파수 대역의 Duty Cycle 기술기준 하에서 광역 IoT 망의 하나인 LoRa 기기의 성능분석 결과를 제시하고, LoRa 기술의 활성화를 위해 기술기준 개정이 필요함을 제안한다. 무선기기는 국가별로 전파법 및 무선설비규칙을 준수하여야 하므로 나라별로 기술기준이 다를 경우 그 성능에 차이가 있을 수 있다. 따라서 향후 IoT 기술의 발전을 위해서는 국내 기술기준에 따른 LoRa 기술의 성능의 한계를 아는 것은 매우 중요하다. 분석 결과, 국내 RFID/USN 주파수 대역의 Duty cycle 기술기준인 0.4초 이내로 데이터 송신을 마치도록 한 규정에 따라 단일 LoRa 기기의 성능이 크게 제한됨을 알 수 있었다. 이에 따라 LoRa IoT 망의 활성화를 위해서는 EU와 유사하도록 국내 Duty Cycle 기술기준을 개정할 필요가 있다고 판단된다.

• 한국전기전자재료학회논문지
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• 제14권8호
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• pp.629-633
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• 2001

Electrical properties of the $\alpha$-In$_2$Se$_3$ single crystals grown by use of the Bridgman technique were examined in the transition temperature range between $\alpha$-phase and $\beta$-phase. $\alpha$-In$_2$Se$_3$ single crystal has ' the rhombohedral structure and lattice constants are a=4.025 $\AA$, c=28.771 $\AA$ in c-axis. The transition temperatures of the stoichiometric $\alpha$-In$_2$Se$_3$ single crystal is 198.8$^{\circ}C$ according to the specimens. The temperature of $\alpha$longrightarrow$\beta$ phase transition decreased but the temperature of $\beta$longrightarrow$\alpha$ phase transition increased as the number of heating-cooling cycle increased.

• 한국유체기계학회 논문집
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• 제6권3호
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• pp.28-35
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• 2003

This paper presents analysis results for the effect of power control strategies on the part load performance of gas turbine based power generation systems utilizing exhaust heat of the gas turbine such as combined cycle power plants and regenerative gas turbines. For the combined cycle, part load efficiency variations were compared among different single shaft gas turbines representing various technology levels. Power control strategies considered were fuel only control and IGV control. It has been observed that gas turbines with higher design performances exhibit superior part load performances. Improvement of part load efficiency of the combined cycle by adopting air flow modulation was analyzed and it was concluded that since the average combined cycle performance is affected by the range of IGV control as well as its temperature control principle, a control strategy appropriate for the load characteristics of the individual plant should be adopted. For the regenerative gas turbine, it is likewise concluded that maintaining exhaust temperature as high as possible by air flow rate modulation is required to increase part load efficiency.

• Steel and Composite Structures
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• 제33권6호
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• pp.777-792
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• 2019

This paper presents a new efficient approach to estimate the S-N type fatigue life assessment curve for S550 high strength steels under low-cycle actions at -60℃. The proposed approach combines a single set of monotonic tension test and one set of fatigue tests to determine the key material damage parameters in the continuum damage mechanics framework. The experimental program in this study examines both the material response under low-cycle actions. The microstructural mechanisms revealed by the Scanning Electron Microscopy (SEM) at the low temperature, furthermore, characterizes the effect due to different strain ratios and low temperature on the low-cycle fatigue life of S550 steels. Anchored on the experimental results, this study validates the S-N curve determined from the proposed approach. The S-N type curve determined from one set of fatigue tests and one set of monotonic tension tests estimates the fatigue life of all specimens under different strain ratios satisfactorily.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3118-3134
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• 2013

This paper deliberates for a multimedia transmission scheme combining multiple description coding (MDC) and network coding (NC). Our goal is to take advantage from the property of MDC to provide quantized and compressed independent and identically distributed (iid) descriptions and also from the benefit of network coding, which uses network resources efficiently to recover lost data in the network. Recently, p-cycle NC has been introduced to recover and protect any lost or distorted descriptions at the receiver part exactly without need of retransmission. So far, MDC have not been explored using this type of NC. Compressed and coded descriptions are transmitted through the network where p-cycle NC is applied. P-cycle based algorithm is proposed for single and multiple descriptions lost. Results show that in the fixed bit rate, the PSNR (Peak Signal to Noise Ratio) of our reconstructed image and also subjective evaluation is improved significantly compared to previous work which is averaging method joint with MDC in order to conceal lost descriptions.

• 한국자동차공학회논문집
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• 제9권6호
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• pp.94-102
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• 2001

The thermodynamic second law analysis, which means available energy or exergy analysis, for the indicated performance of Otto cycle engine has been carried out. Each operating process of the engine is simplified and modeled into the thermodynamic cycle. The calculation of the lost work and exergy through each process has been done with the thermodynamic relations and experimental data. The experimental data were measured from the test of single cylinder Otto cycle engine which operated at 2500 rpm, WOT(Wide Open Throttle) and MBT(Minimum advanced spark timing for Best Torque) condition with different fuels: gasoline, methanol and mixture of butane-methanol called M90. Experimental data such as cylinder pressure, air and fuel flow rate, exhaust gas temperature, inlet gas temperature and etc. were used for the analysis. The proposed model and procedure of the analysis are verified through the comparison of the work done in the study with experimental results. The calculated results show that the greatest lost work is generated during combustion process. And the lost work during expansion, exhaust, compression and induction process follows in order.

• 대한후두음성언어의학회지
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• 제19권2호
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• pp.113-116
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• 2008

Baekgroud and Objectives: The study was purposed to evaluate the relationship between the voice change and the menstrual cycle by measuring the variation of subjective and objective parameters. Materials and Methods: Prospective study of 13 healthy women during 2 mentrual cycles. Their voices were recorded at follicular phase and then luteal phase of the menstrual cycle. We used both single vowel /a/ and sentences for evaluate acoustic parameters. Aerodynamic parameters were also evaluated. Voice handicap index (VHI), and the presence of premenstrual syndromes (PMS) were checked at each period. We used Wilcoxon's signed rank test to compare the parameters of two periods. Results: VHI were 5.1 at both periods (p=0.146) and 92.3% of women were diagnosable with PMS. There were no significant differences in acoustic parameters and aerodynamic parameters between the two periods. Conclusion: This study shows that not only the subjective but also the objective changes of the voice parameters did not exist during the menstrual cycle in women.

• Steel and Composite Structures
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• 제43권4호
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• pp.465-481
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• 2022

This paper presents a comprehensive integrity assessment of welded structural components, including uniform high- and low-cycle fatigue assessment of welded plate joints and fatigue-induced fracture assessment of welded plate joints. This study reports a series of fatigue and fracture tests of welded plate joints under three-point bending. To unify the assessment protocol for high- and low-cycle fatigue of welded plate joints, this study develops a numerical damage assessment framework for both high- and low-cycle fatigue. The calibrated damage material parameters are validated through the smooth coupon specimens. The proposed damage-based fatigue assessment approach describes, with reasonable accuracy, the total fatigue life of welded plate joints under high- and low-cycle fatigue actions. Subsequently, the study performs a tearing assessment on the ductile crack extension of the fatigue-induced crack. The tearing assessment diagram derives from the load-deformation curve of a single-edge notched bend, SE(B) specimen and successfully predicts the load-crack extension relation for the reported welded plate joints during the stable tearing process.