• Journal of Biosystems Engineering
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• 제24권3호
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• pp.195-208
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• 1999

A computer simulation was carried out to investigate draft characteristics of Korean paddy field for obtaining the basic reference to the selection of optimum moldboard type suitable for Korean paddy field conditions. Cylindrical, cylindroidal, semihelical moldboard plows, and one type of oriental Janggi were used for simulation. A series of soil bin experiments was conducted to compare the experimental results with the predicted drafts from computer simulation using the cylindroidal moldboard plow. The computer model predicted draft force with 1~12% error at 12~16cm plowing depth which is the most conventional plowing depth in the rural area in Korea. Thus, the computer model was considered to be good enough for simulation. Due to the different plowing width of experimental plows, specific draft was selected for comparison by computer simulations. Specific draft of cylindrical moldboard plow was ranged from 3 to 6 N/$\textrm{cm}^2$ according to the soil conditions, plowing speed and plowing depth, 2.5~3.0 N/$\textrm{cm}^2$ for semihelical moldboard plow.

• 한국농공학회지
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• 제12권3호
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• pp.2035-2042
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• 1970

Korean Janggi and Western plow to have developed for a long time in the east and west were tested and compared in their draft resistance. The charaderistic of Korean Janggi and plow to be able to make deep plowing, on of the most important factors influeneed the increased yield, were ofserved. The study was undertaken to obtain these basic factors' to device and construct the deep plowing Janggi. The results were as follow; 1. The draft resistance of Korean Janggi far less than that of plow and on the dry field, the influence of soil moisture contant to the draft resistance was larger in the Korean Janggi than in the western plow, but on the rice paddy, there was not differences between them. 2. The plow was more stable than that of Janggi in their operation. 3. The relation ship between the specific draft resistance and plowing depth was shown bygthe carved equation. $$K=Ax+\frac{B}{x}+C$$(K ; specific draft restance, x; plowing depth) A, B, C; Constant controled by soil and instrument factor) 4. Minimam values of the specific draft resistance were as follow; a. On the dry field; Korean Janggi; x = $8{\sim}14cm$ $4K=280{\sim}330gr/cm^2$$ Westean plow; x=$10{\sim}12cm$ $$K=480{\sim}490gr/cm^2$$ 6. On the rice paddy; Korean Janggi; x=$8{\sim}12cm$ $$K=255{\sim}280gr/cm^2$ Western plow; x=$7{\sim}10cm$ $$K=415{\sim}420grc/m^2$$

• 플랜트 저널
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• 제8권4호
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• pp.34-39
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• 2012

석탄화력발전소에서 저품위탄 연소시 통풍저항 변화로 인해 승압송풍기의 운전점에 영향을 주는 것을 분석하여 현재운전점 대비 실속시점을 예측하였다. 연료의 발열량이 낮을수록 통풍저항 증가 속도가 빨라지며, 통풍저항과 승압송풍기의 운전점과는 강한 상관관계가 있음을 확인하였다. 발열량이 낮을수록 통풍저항이 빨리 상승하며 이는 곧 승압송풍기의 운전점이 설계탄 대비해서 실속 한계운전점에 빨리 도달하게 된다. 이를 근거로 현재운전점 대비 한계운전점까지의 운전여유분과 발열량별 통풍저항 증가 속도를 계산하여 실속시점을 예측할 수 있어 송풍기 실속으로 인한 발전출력의 감소나 운전정지에 대비한 정비계획 수립 등 안정운전에 많은 도움이 될 것으로 예상한다.

• The Plant Pathology Journal
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• 제31권3호
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• pp.212-218
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• 2015

In this study, we developed a species-specific PCR assay for rapid and accurate detection of three Xanthomonas species, X. axonopodis pv. poinsettiicola (XAP), X. hyacinthi (XH) and X. campestris pv. zantedeschiae (XCZ), based on their draft genome sequences. XAP, XH and XCZ genomes consist of single chromosomes that contain 5,221, 4,395 and 7,986 protein coding genes, respectively. Species-specific primers were designed from variable regions of the draft genome sequence data and assessed by a PCR-based detection method. These primers were also tested for specificity against 17 allied Xanthomonas species as well as against the host DNA and the microbial community of the host surface. Three primer sets were found to be very specific and no amplification product was obtained with the host DNA and the microbial community of the host surface. In addition, a detection limit of $1pg/{\mu}l$ per PCR reaction was detected when these primer sets were used to amplify corresponding bacterial DNAs. Therefore, these primer sets and the developed species-specific PCR assay represent a valuable, sensitive, and rapid diagnostic tool that can be used to detect three specific pathogens at early stages of infection and may help control diseases.

• 한국미생물·생명공학회지
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• 제51권3호
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• pp.328-331
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• 2023

Genomic information of biotechnologically and industrially important microorganisms provides the basis for understanding their metabolic potential. Here, we report the draft genome sequence of the Neodothiora populina-like yeast strain JAF-11 capable of producing biosurfactant myo-inositol lipids. The draft genome contained genes associated with secondary metabolite biosynthesis, including transport and metabolism of lipids, which are a major component of fungal surfactants. Identification of myo-inositol and acyl chain synthesis genes in the draft genome corresponded to the specific biosurfactant produced by strain JAF-11. Further experimental studies could help to elucidate the genes responsible for the production of biosurfactant by strain JAF-11.

• 무역상무연구
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• 제20권
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• pp.387-421
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• 2003

On the above, a comparison between preliminary draft conventions and comments by the Int'l Chamber of Commerce, contents of preliminary draft convention, problems and alternative are discussed. The conclusions are as follows thereof : The laws of MLEC and MLES made preparation for electronic era of CISG. But electronic circumstances are more changed than the time of regulation of them. Therefore the business world needs a stand-alone convention dealing broadly with the issues of contract formation in electronic commerce. At last, preliminary draft convention delivered a second round. But the base of the instrument was also MLEC and MLES. The revised preliminary draft convention is much amended beyond preliminary draft convention. At its forty-one sessions, the working group reviewed articles 1-11 of the revised preliminary draft convention presented by the secretariat. The remainder was pending until the time of its forty-two sessions. Therefore, on the base of deliberations and decisions of that sessions and them of thirty-six sessions of UNCITRAL, which will be held on comming november, the draft convention which will be prepared by the secretariate, be re-revised preliminary draft convention. According to review of working group on them, preliminary draft convention will officially be draft convention or revise by secretariate. Under these situations, my points of view on draft convention are as follows : As though e-UCP is used carring out side by side with UCP, after e-CISG making in order to adjust CISG to "on" transaction, it is very easy and prompt for business worked to use CISG with e-CISG. This will facilitate ratification of the CISG. For this case, I already presented contents of e-CISG. It is very important for the preliminary draft convention to deal specially with issues related to electronic contracting or to electronic transaction, because according to which way, its contents and scope of application will be different. But the revised draft convention is regretably compromising both them. Consequently, its contents are very confusing and we could not expect its success. If e-CISG will regulate, it is desirable that, if possible, working group has to make the general rule, and the making of useful, practical, affordable rule for electronic commerce, for example Uniform Customs and Practices for Electronic Commerce(e-UEC) in order to solve the specific practical problems, if any, which business currently faces regarding electronic contracting, has to entrust ICC. If working group want to make e-CISG, it is important not to hesitate and take a significant amount of time.

• Fibers and Polymers
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• 제7권1호
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• pp.62-65
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• 2006

Making a good model is one of the most important aspects in the field of a control system. If one makes a good model, one is now ready to make a good controller for the system. The focus of this thesis lies on system modeling, the draft system in specific. In modeling for a draft system, one of the most common methods is the 'least-square method'; however, this method can only be applied to linear systems. For this reason, the draft system, which is non-linear and a time-varying system, needs a new method. This thesis proposes a new method (the MLS method) and demonstrates a possible way of modeling even though a system has input noise and system noise. This thesis proved the adaptability and convergence of the MLS method.

• International Journal of Fluid Machinery and Systems
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• 제2권2호
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• pp.102-109
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• 2009

A design optimization system for Francis turbine was developed. The system consists of design program and CFD solver. Flow passage shapes are optimized automatically by using the system with Multi-Objective Genetic Algorithm (MOGA). In this study, the system was applied to a high specific speed Francis turbine (nSP = 250m-kW). The runner profile and the draft tube shape were optimized to decrease hydraulic losses. As the results, it was shown that the turbine efficiency was improved in wide operating range, furthermore, the height of draft tube was reduced with the hydraulic performance kept.

• 대한설비공학회지:설비저널
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• 제4권2호
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• pp.119-128
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• 1975

Natural draft and flow which low temperature moist gas produces in the chimney of an Ondol heating system were numerically analysed. Among several factors involved inlet gas temperature has the strongest influence on the chimney performance and then next specific humidity of the gas. Thermal conductivity of the chimney wall, however, has little influence on the performance of such a low temperature chimney. Under given flow conditions there exists an optimum chimney height which gives a maximum flow rate for a given chimney diameter. This optimum value of chimney height inereases with increase in chimney diameter, inlet gas temperature and specific humidity.

• 동력기계공학회지
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• 제14권5호
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• pp.30-35
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• 2010

Recently, the large capacity draft fans in power plants had been changed to variable speed type to educe the power consumption. But the fan experienced the unexpected vibration at specific speed regions. In this study, the high vibration frequency of the fan was confirmed and the natural frequency of the rotor were measured and analyzed by FEM programs. It was analyzed that the vibration was caused by the resonance at the frequency, 30.7Hz. So, the rotor vibration characteristic was changed by adjusting the distance between the shaft bearings. It was conformed the high vibration was disappeared over the all operation speeds.