• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.65.2-65
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• 2001

There are not only lots of controllers such as UMC(Unit Master Controller), BMC(Boiler Master Controller), Fuel Flow controller, Air flow controller, Feed water flow controller, S/H R/H Temperature controller and so on, but also compensation controller such as BTU compensator, Fuel/Water ratio controller and O2 Co controller to take automatic control in the super critical once through boiler. It is important to make complete automation of boiler to use the compensation controller like BTU compensator. For example, In case of some boiler condition, operator has to change combustion parameter for changing the coal, on the contrary BTU compensator can calculate set value of the fuel flow and reset the fuel flow demand by itself. This paper shows us the logic and instruction regarding compensation controller of boiler that can be operated automatically.

• Journal of Radiation Industry
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• v.2 no.3
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• pp.149-154
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• 2008

The present study described an antimicrobial spray composition comprising nanosized silica-silver particles, in which nano-silver is bound to silica molecules and a water-soluble polymer, the nanosized silica-silver particles prepared by irradiating a solution comprising a silver salt, silicate and the water-soluble polymer with radiation rays. According to a surfactant addition, the compositions were not turbid and were colorless. Also samples (cotton fabrics and wallpaper) were treated with the compositions also did not cause any stains even after drying under sunshine and at $80^{\circ}C$. Our results suggested that the spray formulation product was of practical use to control indoor fungi.

• Food Science and Biotechnology
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• v.27 no.6
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• pp.1871-1875
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• 2018

Preventive and curative activity of postharvest treatments with chitosan nanoparticles (CS) and chitosan biocomposites loaded with pepper tree essential oil (CS-PEO) against anthracnose were evaluated on Avocado (Persea americana) cv. Hass artificially inoculated in rind wounds. After 10 days of storage significant preventive and curative activity against Colletotrichum gloeosporioides was observed with the absence of internal damage by applying CS and CS-PEO. Quality parameters like water losses and firmness changes were assessed on fruit treated. CS and CS-PEO were effective to reduce water losses and firmness losses.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.4
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• pp.37-45
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• 2002

The development process of KSR-III propulsion feeding system is subscripted. The purpose of propulsion feeding system is to feed a certain amount of propellant from propellant tank to engine by the end of combustion. Pressure-fed liquid rocket, KSR-III has the unique characteristics of both pressure regulator and cavitation venturi as a passive flow control device. Main parameters of feeding system are confirmed by both water test and CFD(전산유체) technique. Flow control effect with venturi is confirmed by water test. Initial stabilization characteristic of pressure regulator is confirmed by real propellant test. And, to avoid the effect of resonance between rocket and feeding system, this article deal with POGO(포고) analysis to the feeding system.

• Wind and Structures
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• v.29 no.1
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• pp.33-41
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• 2019

The interaction of head waves with an infinite row of identical, equally spaced, rectangular breakwaters is investigated in the presence of uneven bottom topography. Using linear water wave theory and matched eigenfunction expansion method, the boundary value problem is transformed into a system of linear algebraic equations which are numerically solved to know the velocity potentials completely. Utilizing this method, reflected and transmitted wave energy are computed for different physical parameters along with the wave field in the vicinity of breakwaters. It is observed that the wave field becomes more complicated when the incoming wavelength becomes smaller than the channel width. A critical ratio of the gap width to the channel width, corresponding to the inflection point of the transmitted energy variation, is identified for which 1/3 of the total energy is transmitted. Similarly, depending on the incident wavelength, there is a critical breakwater width for which a minimum energy is transmitted. Further, the accuracy of the computed results is verified by using the derived energy relation.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.163-169
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• 2019

The robust controller synthesis and analysis of the water level process in the U-tube system generator (UTSG) is addressed in this paper. The parameter uncertainties of the steam generator (SG) are modeled as multiplicative perturbations which are normalized by designing suitable weighting functions. The relative errors of the nominal SG model with respect to the other operating power level models are employed to specify the weighting functions for normalizing the plant uncertainties. Then, a robust controller is designed based on ${\mu}$-synthesis and D-K iteration, and its stability robustness is verified over the whole range of power operations. A gain-scheduled controller with $H_{\infty}$-synthesis is also designed to compare its robustness with the proposed controller. The stability analysis is accomplished and compared with the previous QFT design. The ${\mu}$-analysis of the system shows that the proposed controller has a favorable stability robustness for the whole range of operating power conditions. The proposed controller response is simulated against the power level deviation in start-up and shutdown stages and compared with the other concerning controllers.

• Fisheries and Aquatic Sciences
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• v.25 no.8
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• pp.409-416
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• 2022

This study aims to know the effect of water-extracted horseradish Moringa oleifera leaf and KW21 fertilizer combination application on the density of Nannochloropsis sp. It was conducted in the Natural Food Laboratory of State Polytechnique, Tual. The experiment used complete randomized design with 5 treatments and 3 replications: A (25% horseradish leaf extract + 75% KW21), B (50% horseradish leaf extract + 50% KW21), C (75% horseradish leaf extract + 25% KW21), D (positive control of 100% KW21), and E (negative control of 100% horseradish leaf extract). Results showed that Treatment C yielded the best result, both the highest density of Nannochloropsis sp. and suitable harvest time.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.12 no.1
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• pp.2-11
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• 1983

The solar energy retention rate of a flat plate collector can be increased by increasing water flow rate through the collector which also increases the pumping energy incurred in obtaining that solar energy. The problem of optimal flow rate is formulated to fit within the framework of pontryagin's maximum principle and with a few simplifying assumptions, an optimal solution that can be easily implemented is obtaincd, The optimal solution is used in the simulation of a solar heating system using actual climatological data and the results are compared with that of on-off control. The result that not only the object function but, In some cases, also the solar energy retention rate the collector is increased. In is also found that the optimal control gets more advantageous as the solar insolation level gets lower, and also as tile cost of auxiliary heating fuel gets higher.

• Journal of Plant Biotechnology
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• v.50
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• pp.255-266
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• 2023

Hyperhydricity is a physiological anomaly that significantly affects the growth and proliferation rate of crops cultivated by tissue culture techniques. To better understand the mechanisms that govern hyperhydricity incidence, we examined the effects of several media components, particularly cytokinin and gelling agents. These elements were found to be influential in both in vitro propagation and the development of hyperhydricity. Our study revealed that Arabidopsis thaliana seedlings had a greater manifestation of hyperhydricity symptoms when exposed to high cytokinin concentrations compared with the control. The presence of gelrite led to the manifestation of hyperhydric symptoms by elevated water build-up in the apoplast. The phenomenon of stomata closure was observed in the hyperhydric leaves, resulting in an increased ability to retain water and a decrease in the transpiration rates when compared to their respective control leaves. Additionally, histological examinations of the cross sections of hyperhydric leaves revealed an irregular cellular arrangement and large intercellular spaces. Furthermore, hyperhydric seedlings displayed impaired cuticular development in comparison to their normal seedlings.

• The Korean Journal of Food And Nutrition
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• v.17 no.1
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• pp.25-31
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• 2004

The quality and sensory characteristics of kimchi during fermentation at 15 $^{\circ}C$ were evaluated. Kimchi was prepared with Chineses cabbage which was brined in 10% salt water added dill hot-water extracts(DK) and stevia hot-water extracts(SK) respectively. The pHs and reducing sugar contents of kimchi were decreased with increasing the fermentation time whereas lactic acid(%) was increased. The pH of DK was lower than control, and the lactic acid(%) contents of DK, SK were equal or higher than control in the first stage of fermentation. Also, the reducing sugar contents of DK, SK were lower than control. These results showed that the fermentation of DK and SK were faster than that of control in the first stage of fermentation. But the lactic acid(%) contents of DK, SK were higher than control after the 12th day of fermentation. It showed that it is possible to extend the preservation of kimchi. With increasing fermentation time, the L value of kimchi juice was increased, and the a value was decreased, and the b value was constant. Especially, the a value of DK, SK was higher than control. It meant that DK, SK kept more carotenoids in kimchi than control. On the 6th day of fermentation, the sensory evaluation analyzed by ANOVA followed Duncan's multiple range test showed that the levels of the green smell and the moldy flavor of DK were significantly lower than control(p<0.05) and the levels of the green smell, the green flavor and the moldy smell of SK were significantly lower than control(p<0.05), too. And the level of overall flavor of DK, SK was higher than control. The most preference among experimental groups was SK and then control, DK. The levels of TBARS of DK, SK were generally lower than control, and the level of TBARS of DK was lower than SK.