• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.897-907
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• 2020

The flow characteristics of reactor fuel assembly always intrigue the designers and the experimentalists among the myriad phenomena that occur simultaneously in a nuclear core. In this work, the visual experimental method has been developed on the basis of refraction index matching (RIM) and particle image velocimetry (PIV) techniques to investigate the detailed flow characteristics in China fast reactor fuel subassembly. A 7-rod bundle of simulated fuel subassembly was fabricated for fine examination of flow characteristics in different subchannels. The experiments were performed at condition of Re=6500 (axial bulk velocity 1.6 m/s) and the fluid medium was maintained at 30℃ and 1.0 bar during operation. As for results, axial and lateral flow features were observed. It is shown that the spiral wire has an inhibitory effect on axial flow and significant intensity of lateral flow mixing effect is induced by the wire. The root mean square (RMS) of lateral velocity fluctuation was acquired after data processing, which indicates the strong turbulence characteristics in different flow subchannels.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.91-96
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• 2021

This study was conducted to improve the operating conditions of an adsorption tower filled with potassium impregnated activated carbon for high hydrogen sulfide capture capacity. Heat treatment modified the surface properties of activated carbon, and ultimately determined its adsorption capacity. The activated carbon doped with potassium showed 57 times more adsorption at room temperature than that of using the raw adsorbent. It is believed that uniform pore formation and strong bonding of the potassium on the surface of carbon contributed to the chemical and physical absorption of hydrogen sulfide. The SEM analysis on the surface structure of various commercial carbons showed that the modification of surface properties through the heat treatment generated the destruction of pore structures resulted in the decrease of the absorption performance. The pressure drop across the activated carbon bed was closely related with the grain size and shape. The optimum size of irregularly shaped activated carbon granules was 2~4 mesh indicating economical feasibility.

• Resources Recycling
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• v.22 no.1
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• pp.55-63
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• 2013

Considering considerable contents of vanadium and tungsten in spent SCR DeNOx catalysts, separation and recovery of those metals are required. In this respect, commercial anion exchange resin (MP600) was employed to recover vanadium from the synthetic solution of ammonium metavanadate. Experimental results indicated that vanadium exist as anion under the acidic condition (pH 2 ~ 6) and adsorbed on the resin. Although the adsorption rate was increased with temperature, the maximum amount of adsorption was not affected by temperature. Desorption took place under either strong acidic (less than pH 1) or strong caustic (higher than pH 13) condition. However, desorption seldom took place under moderate conditions (pH 3~11). Furthermore, adsorption equilibrium results agreed well with Freundlich isotherm and pseudo-second-order reactions. And, adsorption energy was evaluated using Dubinin-Radushkevich and Temkin isotherm.

• Korean Journal of Materials Research
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• v.22 no.4
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• pp.185-189
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• 2012

We report plasma-assisted molecular beam epitaxy of $In_XGa_{1-X}N$ films on c-plane sapphire substrates. Prior to the growth of $In_XGa_{1-X}N$ films, GaN film was grown on the nitride c-plane sapphire substrate by two-dimensional (2D) growth mode. For the growth of GaN, Ga flux of $3.7{\times}10^{-8}$ torr as a beam equivalent pressure (BEP) and a plasma power of 150 W with a nitrogen flow rate of 0.76 sccm were fixed. The growth of 2D GaN growth was confirmed by $in-situ$ reflection high-energy electron diffraction (RHEED) by observing a streaky RHEED pattern with a strong specular spot. InN films showed lower growth rates even with the same growth conditions (same growth temperature, same plasma condition, and same BEP value of III element) than those of GaN films. It was observed that the growth rate of GaN is 1.7 times higher than that of InN, which is probably caused by the higher vapor pressure of In. For the growth of $In_xGa_{1-x}N$ films with different In compositions, total III-element flux (Ga plus In BEPs) was set to $3.7{\times}10^{-8}$ torr, which was the BEP value for the 2D growth of GaN. The In compositions of the $In_xGa_{1-x}N$ films were determined to be 28, 41, 45, and 53% based on the peak position of (0002) reflection in x-ray ${\theta}-2{\theta}$ measurements. The growth of $In_xGa_{1-x}N$ films did not show a streaky RHEED pattern but showed spotty patterns with weak streaky lines. This means that the net sticking coefficients of In and Ga, considered based on the growth rates of GaN and InN, are not the only factor governing the growth mode; another factor such as migration velocity should be considered. The sample with an In composition of 41% showed the lowest full width at half maximum value of 0.20 degree from the x-ray (0002) omega rocking curve measurements and the lowest root mean square roughness value of 0.71 nm.

• Journal of Conservation Science
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• v.31 no.2
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• pp.87-94
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• 2015

Plastic artwork can be appeared crack, change of color and whitening event by various environment conditions. A large scale plastic artwork often exhibits in outside it will be directly degraded by physical and chemical degradation factor such as strong sunlight, high humidity and rainfall. We should know degradation characteristic of plastics to prevent these damages. In this study, we studied degradation characteristic of plastics (5 types of wide use plastics; polypropylene, polystyrene, polyethylene, polyvinyl chloride, polyurethane) depending on various artificial degradation conditions such as high temperature, ultraviolet and these complex conditions (high temperature and ultraviolet). As a result, polypropylene, polystyrene and polyethylene show the most visible change especially polypropylene, polystyrene. Polypropylene didn't show a great change degree of tensile strength and contact angle, on the other hand polystyrene did. Polypropylene and polystyrene weakened by photo degradation, polyvinyl chloride and polyurethane had relatively good light stability. Also the high temperature and complex conditions were most degradation characteristic. High temperature worked for degradation catalyst because its energy can not enough worked for cut off binding energy of plastics while ultraviolet condition effected as directly degradation condition. Though following results, we expect it can be applied to investigation of degradation factor depending on plastic artwork materials and basic result of plastic artworks conservation.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.420-425
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• 2011

In general, the decomposition of $CaSO_4$ formed by sulfation reaction in the in-furnace desulfurization process using limestone has strong effect on the desulfurization reaction under the oxy-fuel combustion condition. In this study, the conversion rates were measured and reaction rates were calculated in order to investigate the effects of the experimental variables such as temperature and the concentrations of $CO_2$, $O_2$, $SO_2$, on the $CaSO_4$ decomposition reaction using DTF (Drop Tube Furnace) in the desulfurization reaction. The conversion rate and the reaction rate of $CaSO_4$ decomposition reaction were increased with reaction temperature. $CO_2$ concentration has little effect on $CaSO_4$ decomposition reaction in the presence of $O_2$. Under the same experimental conditions, the decomposition rate of $CaSO_4$ was enhanced with the decreasing the $O_2$ concentration, but vice versa with the increasing of $SO_2$ concentration.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.740-744
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• 2005

Perovskite-type oxide $La_{1-x}Sr_xCo_{1-y}Fe_yO_{3-{\delta}}$ sols were prepared by sol-gel method using $La(NO_3)_3{\cdot}xH_2O$, $Sr(NO_3)_2$, $Co(NO_3)_2{\cdot}6H_2O$ and $Fe(NO_3)_3{\cdot}9H_2O$ as starting materials. The properties of the perovskite-type oxide sols were investigated by viscometer, FT-IR, TG-DTA and XRD. The prepared sols showed 1.16 cp in average viscosity, and a strong acidic condition of pH 0.5, irrespective of composition of the starting materials. The viscosity of sols at the same volume decreases, but the gelation time of sols, at which the sol viscosity increases rapidly, increases when increasing La concentration in composition of starting materials.

• Journal of the Korean Institute of Rural Architecture
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• v.21 no.2
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• pp.19-26
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• 2019

Pungsu theory is important one in the site selection and lay-out of traditional Korean village and house. In this aspect, Study with a view of Pungsu theory might be used as a proper method for understanding the traditional architecture in Korea. In this context, this study analyzes the Jeong, Dong-Ho's house which is designated no. 19 as an important folk cultural heritage, located in Jigok Ochu-gil 133-62, Godeok-myon, Yesan-gun, Chungnam province. The analysis of the site and space lay-out is carried out by Yong(Dragon), Hyoel(Auspicious Spot), Sa(Sands), Su(Water) aspects of the Pungsu(Fengshui) Hyungsei-ron. The house is depending upon soft dragon vein connecting with a earth type rear mountain. It looks southeast direction, Gonjwasonhyang(乾坐巽向). The hyeolseong(穴星) has classical venus shape, and there is no faults relatively. The Sasinsa condition is almost perfect that right blue dragon and left white tiger surround the hyeol with 3-4 layers and the facing mountain covers the front open area. The water flowing from inside of left and right mountain is joined in front of the house so it could stop flowing out of vital energy. Bibo forest(裨補樹) is placed properly to protect the easy disclose of water outlet. The house is well organized western house(西四宅) by analysis of Dongseosataek-ron(東西四宅論). Through the analysis, I found that the house has good Pungsu(Fengshui) environment fitted with Pungsu Hyungsei-ron. The house composed of small thatched roof is enclosed several times by low hills of back, left and right side. So it is believed that the site might be carefully evaluated by Yong, Hyoel, Sa, Su of Hyeongsei-ron for knowing whether the site condition could minimize the demage by strong winds and protect from the winter cold wind and secure water for drinking and farming and then selected. The method of Pungsu for evaluating the geographical condition of surrounding of a site is used as a traditional site analysis method for evaluating the suitability of long-term well and safe residence.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.269-276
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• 2004

The reclaimed land has peculiar characteristic of nature environment unlike midtown or inland and also, in comparison with inland, has bad weather condition, such as low temperature, strong wind, excessive sunshine, and moisture involved in a salt. Therefore the case of developing water front needs understanding characteristic of weather environment mused by reclamation in detail and proper development and organized maintenance. If development which doesn't investigate topographic and climate characteristic sufficiently is drove ahead, a rise of expense for energy and maintenance is going to be mused by deteriorating weather environmental, occurring a flaw of facility and calculating inaccurate capacity of facility. We looked into the weather state and drew up the standard weather data of the newport area in Busan which is reclaiming and developing now. In this research at the base qf the standard weather data, we calculate the dynamic peak loads for commerce, business and residence and then we utilize the results of the load calculation as basic information to determine facility capacity in the rear city of the newport area.

• Journal of Sasang Constitutional Medicine
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• v.29 no.3
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• pp.211-223
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• 2017

Objectives The purpose of this study is to understand the formation of Jogakdaehwang-tang(JD-T)'s patholoy and the compositional change of it in Sasang Constitutional Medicine(SCM). Methods The pathologic condition in which JD-T was used and the change of its composition was studied in SCM Results and Conclusions 1. Jogak and Daehwang in "Dongmuyoogo Haedong" were presented with Ungdam because of the common purpose flowing the energy of lung. Therapeutic method for exogenous Ungibyeong in "Dongyisusebowon sangchobongwon" was subdivided into Hangwul's treated by Ungdam, and the heat pattern featuring contagious cold and constipation, treated by Jogakhwanggeumdaehwang-tang(JHD-T). 2. JD-T in "Dongyisusebowon Gabogubon" was used for Yangdok and Onbyeong which are exogenous disease causing by heat. The composition of JD-T has been completed as it included Mahwang, Gilgyeong, and Seungma derived from prescriptions relevant with Yangdok. 3. JD-T in "Dongyisusebowon Sinchukbon(Sinchukbon)" was included in pathology of Ganyeol, and it substituted Galgeunhaegi-tang(GH-T) for Onbyeong, not for Yangdok, so Galgeun and Seungma became the main drug in JD-T. Galgeunseung-gitang(GS-T) was created for treating heat pattern owing to Daehwang, its main drug, and moreover Jogak's effect is too strong. Therefore, Mahwang, Hwanggeum and Gilgyeong was excluded from the composition of JD-T. 4. The origins of JD-T could be Yiseonggugo-hwan, Daesiho-tang, Jowiseungchung-tang, Heukno-hwan, and GH-T. The change of JD-T went for them throughout JHD-T to JD-T. JD-T in "Sinchukbon" consists of Galgeun and Daehwang which directly gets rid of severe heat from small intestine, and Jogak and Seungma which help to eliminate mild heat existing from small intestine throughout nose to flesh.