• 한국통신학회논문지
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• 제25권7A호
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• pp.986-993
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• 2000

In this paper, we analyze transmission characteristics of ultrashort laser pulses using the properties of high-order pulses which are systematically obtained following their orders. The high-order pulses are easily derived from a modified PRS system model. But we make clear they are very useful to cover wider area and to show more accurate transmission characteristics of ultrashort pulses than Gaussian or Sech pulse approximations used conventionally. These are based on the fact that the spectra and bandwidths of the high-order pulses are geautifully related to their orders. First modifying the generalized PRS system model, we propose a new model for deriving any type of high-order pulse. And we offer a novel analysis method of ultrashort pulse transmission varying the order of the pulse from n=1 to n=100, we obtain spectra of ultrashort pulses with 1(ps)∼150(fs) FWHM's, which are widely used in optical pulse communications. One-step further, we derive PSD's of their pulse-tr ins when they are applied to Unipolar signaling scheme. These PSD's are decided in the range of possible pulse intervals. All of these results are not only coincided with some conventional experimental works but will be applied to any pioneering ultrashort pulse in the future.

• 소음진동
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• 제3권2호
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• pp.163-167
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• 1993

Suction and discharge valves of special type refrigerant compressor are designed by finite element method for effective valve design development procedure. It is well known that valve dynamic characteristics, for example, the natural frequencies and vibration modes, are necessary for the computer simulation of compressor valve dynamics, the analysis of flow patterns, noise, impact stresses and their propagation phenomena. This paper has analysed the natural frequencies and vibration modes for the first three orders under the given special boundary conditions and the experiments are conducted by laser holography. And also stress distribution is analysed and experiment by strain gage is followed.

• Korean Chemical Engineering Research
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• 제48권6호
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• pp.752-756
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• 2010

시화/반월 산단 내에서 활성탄 흡착탑을 사용하는 업종 중 도장 공정을 사용하는 대표적인 업체에서 수거한 폐활성탄의 탈착특성을 조사하였다. 탈착특성을 조사하기 위하여 열중량분석기(Thermogravimetric Analyzer)를 사용하였다. 탈착특성 자료를 바탕으로 탈착 특성비교에 중요한 요소인 반응차수와 활성화에너지를 구하기 위하여 Friedman법과 Freeman-carroll법을 사용하였다. 도장 공정에서 수거한 폐활성탄으로 Friedman법을 이용하여 활성화에너지를 계산한 결과 20.6~43.2 kJ/mol을 나타내었으며, Freeman-Carroll법을 이용하여 활성화에너지와 반응 차수를 계산한 결과 활성화에너지는 12.3~26.5 kJ/mol, 반응 차수는 0.1~1.7을 나타내었다.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1597-1609
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• 2015

This paper introduces the fundamentals of the conventional LC low-pass filter circuit in the fractional domain. First, we study the new fundamentals of fractional-order LC low-pass filter circuit including the pure real angular frequency, the pure imaginary angular frequency and the short circuit angular frequency. Moreover, sensitivity analysis of the impedance characteristics and phase characteristics of the LC low-pass filter circuit with respect to the system variables is studied in detail, which shows the greater flexibility of the fractional-order filter circuit in designs. Furthermore, from the filtering property perspective, we systematically investigate the effects of the system variables (LC, frequency f and fractional orders) on the amplitude-frequency characteristics and phase-frequency characteristics. In addition, the detailed analyses of the cut-off frequency and filter factor are presented. Numerical experimental results are presented to verify the theoretical results introduced in this paper.

• Nuclear Engineering and Technology
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• 제49권6호
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• pp.1135-1142
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• 2017

The applicability of the algebraic collapsing acceleration (ACA) technique to the method of characteristics (MOC) in cases with scattering anisotropy and/or linear sources was investigated. Previously, the ACA was proven successful in cases with isotropic scattering and uniform (step) sources. A presentation is first made of the MOC implementation, available in the DRAGON5 code. Two categories of schemes are available for integrating the propagation equations: (1) the first category is based on exact integration and leads to the classical step characteristics (SC) and linear discontinuous characteristics (LDC) schemes and (2) the second category leads to diamond differencing schemes of various orders in space. The acceleration of these MOC schemes using a combination of the generalized minimal residual [GMRES(m)] method preconditioned with the ACA technique was focused on. Numerical results are provided for a two-dimensional (2D) eight-symmetry pressurized water reactor (PWR) assembly mockup in the context of the DRAGON5 code.

• Journal of Species Research
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• 제8권2호
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• pp.197-214
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• 2019

The taxonomic hierarchy of the phylum Proteobacteria was assessed, after which the isolation and classification state of Proteobacteria species with valid names for Korean indigenous isolates were studied. The hierarchical taxonomic system of the phylum Proteobacteria began in 1809 when the genus Polyangium was first reported and has been generally adopted from 2001 based on the road map of Bergey's Manual of Systematic Bacteriology. Until February 2018, the phylum Proteobacteria consisted of eight classes, 44 orders, 120 families, and more than 1,000 genera. Proteobacteria species isolated from various environments in Korea have been reported since 1999, and 644 species have been approved as of February 2018. In this study, all novel Proteobacteria species from Korean environments were affiliated with four classes, 25 orders, 65 families, and 261 genera. A total of 304 species belonged to the class Alphaproteobacteria, 257 species to the class Gammaproteobacteria, 82 species to the class Betaproteobacteria, and one species to the class Epsilonproteobacteria. The predominant orders were Rhodobacterales, Sphingomonadales, Burkholderiales, Lysobacterales and Alteromonadales. The most diverse and greatest number of novel Proteobacteria species were isolated from marine environments. Proteobacteria species were isolated from the whole territory of Korea, with especially large numbers from the regions of Chungnam/Daejeon, Gyeonggi/Seoul/Incheon, and Jeonnam/Gwangju. Most Halomonadaceae species isolated from Korean fermented foods and solar salterns were halophilic or halotolerant. Air-borne members of the genera Microvirga, Methylobacterium, and Massilia had common characteristics in terms of G+C content, major respiratory quinones, and major polar lipids.

• 한국전산구조공학회논문집
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• 제23권3호
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• pp.325-330
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• 2010

현행 토목 설계분야에서는 BIM(Building Information Modeling)기반의 3차원 객체모델의 활용이 미미한 수준이다. 본 논문에서는 철도교량의 상부구조인 PSC 박스거더에 대하여 BIM기반의 3차원 객체 모델을 구성하였으며, 모델의 기초구성은 파트(Part)모델로 되어있다. 파트(Part)모델은 여러 가지 단위 모델 중 최소 단위이며, 이것은 설계대상 구조물의 특성을 반영하여 계층구조를 가진다. 3차원 객체 모델은 설계자의 설계변경의도를 신속하게 반영할 수 있어야 한다. 실제 설계과정에서는 반복적인 설계변경이 발생할 수 있기 때문이다. 이를 위하여 설계변수를 파라미터로 구분을 하였으며 그 파라미터들은 3차원 객체모델의 정보와 연계되어 있기 때문에 설계 변경에 신속하게 대응할 수 있다. 이 연구에서 우리는 3차원객체 모델을 토목설계분야에 활용하여 얻을 수 있는 이점을 고찰하였다. 또한 PSC 박스거더의 3차원 객체 모델의 효율적인 적용방안을 제시하였다.

• 한국의료질향상학회지
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• 제4권2호
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• pp.210-221
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• 1997

Background : Willingness to satisfy patients(WSP) among nurses is essential to promoting patient satisfaction which is a critical component in the quality of health care and its outcomes. This study was carried out to empirically find out the affecting factors of WSP among nurses in hospital settings. Methods : The model contains seven job relating determinants and two intervening variables as follows: i) job relating variables of professional status, task requirements, pay, physician-nurse interaction, nurse-nurse interaction, organizational policies, and autonomy, ii) intervening variables of job satisfaction and organizational commitment. Data were collected from 205 nurses in two general hospitals owned by one foundation located in Pusan, Korea, using a structured and self-administered questionnaire. Results : The major results were as follows: First, the results of ANOVA on WPS by personal characteristics showed a statistically significant relationships between WPS and hierarchical orders(p<.01) ana tenure(p<.10). Comparing with the lower orders and shorter tenure, the higher orders and the longer tenure showed better WPS. Second, the results of simple correlation analysis between WPS and determinants and intervening variables showed the following variables, in order of importance, were statistically significant(p<.01): work satisfaction(+), organizational commitment(+), task requirements(+), nurse-interaction(+), professional status(+), physician-nurse interaction(+). Third, the results of path analysis showed that two intervening variables of job satisfaction and organizational commitment, and three determinants of task requirements, professional status, and nurse-nurse interaction had a positively significant direct effect to WPS. Conclusion : The results suggest that nurses who are more satisfied with task requirements, status, nurse-nurse interaction, overall job satisfaction, and organizational commitment, will behave in ways that patients find more satisfied.

• 한국약용작물학회지
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• 제27권3호
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• pp.167-172
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• 2019

Background: Angelica acutiloba Kitagawa belongs to the flowering plant family Apiaceae. Its young leaves are consumed as a vegetable, and its roots have medicinal properties. This study was conducted to analyze the seed germination characteristics of A. acutiloba according to its ripening stages. Methods and Results: The seeds were harvested from a research farm managed by the Department of Herbal Crop Research, Rural Development Administration in 2018 and were divided into six groups according to their specific gravities. In particular, we studied the effect of harvesting periods and umbel orders on seed characteristics. The results showed that the rates of germination, emergence, and early growth improved as the specific gravity of the seeds increased. In addition, the germination rates of the seeds harvested in mid July and early August were significantly higher than those harvested in the other seasons, and the seeds obtained from the first floret had the greatest mass and weight. Conclusions: In this study, we demonstrated that it is possible to improve the germination rate by appropriate selection of seeds and harvesting period both of which are closely related to seed maturity.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권6호
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• pp.442-450
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• 1999

In this paper, we have fabricated Langmuir-Blodgett(LB) films by LB technique and evaluated the deposited status of LB films by UV-vis absorbance. It was found thatthe thickness of LB films per a layer are $27~30[{\AA}]$ by ellipsometry. The responeses between LB films and organic gases were investigated using by I-V characteristics of LB films and F-R diagram of quartz crystal. The response orders between LB films and organic gases observed by I-V characteristics were as following ; chloroform, methanol, acetone and ethanol in the order of their short chain length. The response mechanism between LB films and organic gases observed by F-R diagram of quartz crystal could be modeled on adsorption at surface, penetration, desorption at surface and inside.