• 한국세라믹학회지
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• 제44권3호
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• pp.152-156
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• 2007

Tungsten carbide powder was synthesized by SHS (self-propagating high-temperature synthesis). Except $WO_{3}$, each concentration of raw material ($WO_{3},\;Mg,\;NaCl,\;Na_{2}CO_{3},\;C$) was investigated. Final product was characterized by XRD and SEM. X-ray data demonstrated that the $NaCl+Na_{2}CO_{3}$ combined mixture has superiority in the WC formation process. Single phase and submicrometer WC powder was synthesized at the temperature below $1600^{\circ}C$. The role of sodium salts in combustion process was discussed, and chemical mechanism of WC formation was proposed. WC powder prepared by salt-assisted combustion synthesis has a size $0.2{\sim}3\;{\mu}m$ and low agglomeration degree.

• Journal of Advanced Marine Engineering and Technology
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• 제40권6호
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• pp.458-467
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• 2016

소금은 인간의 생리활동에서 매우 중요한 물질로서 섭취한 영양소를 혈액 안으로 수송하는 역할을 한다. 따라서 소금에는 카드늄, 수은, 납, 비소와 같은 유해성분이 전혀 포함되지 않는 것이 가장 이상적이다. 그러나 소금은 모든 물질이 용존 되어 있는 해수로부터 얻어지기 때문에 기술적 한계로 불가불 미량의 유해성분이 포함되는 것을 법적으로 용인하고 있다. 본 논문은 해수의 농도증가에 따른 순차석출 현상을 응용하여 '$15^{\circ}C$ 저온진공건조기술'로 유해성분이 전혀 포함되지 않는 식탁염의 새로운 제조방법에 대한 실험결과를 보고하였다. 본 연구결과를 전통적인 천일염의 제조공정에 확장 적용하면 세계적 명품 소금의 제조도 가능하다.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1324-1331
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• 2023

In the present work, we carried out a molecular dynamics study of the kinetic properties of the FLiNaK molten salt, as well as a detailed study of the structure of this salt melt. The high value of the self-diffusion coefficient of fluorine ions is due to the large number of Coulomb repulsions between the most numerous negative ions. The calculated values of shear viscosity are in good agreement with the experimental data, as well as with the reference data obtained on the basis of finding the most reliable data. The total and partial functions of the radial distribution are calculated. According to the statistical analysis, fluorine ions have the greatest numerical diversity in the environment of similar ions, and sodium ions with the lowest representation in FLiNaK, have the least such diversity. For the subsystem of fluorine ions, the rotational symmetry of the fifth order is the most pronounced. Some of the fluorine ions form linear chains consisting of three atoms, which are not formed for positive ions. The results of the work give an understanding of the behavior molten FLiNaK under operating conditions in a molten salt reactor and will find application in future studies of this molten salt.

• 한국식품저장유통학회지
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• 제8권3호
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• pp.313-319
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• 2001

도토리 묵을 인스턴트화 하기 위하여 생묵을 동결건조하여 재수화 시간, 재수화 용액의 염농도(0, 1, 2%) 및 온도(20, 70, 80, 9$0^{\circ}C$)에 따른 재수화 특성과 품질특성을 비교하였다. 동결건조묵의 최적 재수화 시간은 15분으로, Cooling 시간은 3분으로 각각 결정되었다. 재수화 효율은 재수화 용액의 염농도가 1%에서 가장 우수하였으며 재수화 온도가 높을수록 좋았다. 수분흡수속도상수도 재수화 온도가 증가할수록 놀았으며 1%의 염농도에서의 재수화가 온도변화에 따라 가장 놀은 활성화에너지를 가졌다. 동결건조묵의 재수화 후 표면색도와 재수화성 등을 고려해 볼 때 1% 염농도에서의 재수화가 묵의 품질에 우수한 것으로 평가되었다.

• 태양에너지
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• 제8권1호
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• pp.13-21
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• 1988

Heat transfer phenomena in a high-temperature heat storage unit were investigated using molten salts. Carbonate salt, an equimolar mixture of $Li_2CO_3$ and $K_2CO_3$, which melts at $505^{\circ}C$ with a latent heat of 82 cal/g, was selected as the most promising latent heat storage material based on its low cost and excellent thermophysical properties at moderately high temperatures. It was also found that nitrate salts were good candidates of sensible heat storage materials. For the carbonate salt to be utilized commercially, however, several means of enhancing thermal recovery must be explored by promoting heat conduction through the solid salt formed during the heat discharge period. These would be achieved by the additions of aluminum screens and wool, and stainless fins. Finally, experimental results of moving boundary of phase change were well compared with predictied values obtained from the approximate solution.

• 한국식품영양과학회지
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• 제43권12호
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• pp.1913-1919
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• 2014

이동식 자동절임장비에서 염농도 29.6%의 염수로 $30^{\circ}C$에서 4시간 절인 배추로 담근 고염도 김치의 품질은 김치공장에서 12% 염수로 $10^{\circ}C$에서 16시간 절인 배추로 담근 저염도김치의 품질보다 전체적인 맛과 짠맛에서 더 높았고 다른 요소들은 유의적인 차이가 없었다. 특히 전체적인 맛과 짠맛에 대한 기호도는 5% 유의수준에서 차이가 있었다(P<0.05). 즉 고농도 염수로 고온에서 단시간 절인 배추의 품질이 저농도에서 저온으로 장시간 절인 배추의 품질보다 우수하였다. 이러한 결과는 김치공장의 생산성 향상을 위해 배추의 절임공정을 개선하는 데 방향을 제시하는 것이고, 이동식 배추절임 자동화장비를 실용화하는 데 근거가 될 것이다.

• 한국재료학회지
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• 제30권4호
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• pp.176-183
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• 2020

The high-temperature stability of YSZ specimens fabricated by die pressure and cold isostatic press (CIP) is investigated in CaCl₂-CaF₂-CaO molten salt at 1,150 ℃. The experimental results are as follows: green density 46.7 % and 50.9 %; sintering density 93.3 % and 99.3 % for die press and CIP, respectively. YSZ foremd by CIP exhibits higher stability than YSZ formed by die press due to denseness dependency after high-temperature stability test. YSZ shows peaks mainly attributed to CaZrO₃, with a small t-ZrO₂ peak, unlike the high-intensity tetragonal-ZrO₂ (t-ZrO₂) peak observed for the asreceived specimen. The t-ZrO₂ phase of YSZ is likely stabilized by Y₂O₃, and the leaching of Y₂O₃ results in phase transformation from t-ZrO₂ to m-ZrO₂. CaZrO₃ likely forms from the reaction between CaO and m-ZrO₂. As the exposure time increases, more CaZrO₃ is observed in the internal region of YSZ, which could be attributed to the inward diffusion of molten salt and outward diffusion of the stabilizer (Y₂O₃) through the pores. This results in greater susceptibility to phase transformation and CaZrO₃ formation. To use SOM anodes for the electroreduction of various metals, YSZ stability must be improved by adjusting the high-density in the forming process.

• Membrane and Water Treatment
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• 제12권1호
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• pp.1-9
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• 2021

This study optimized the chemical cleaning process of discarded RO membranes for reuse in less demanding separation processes. The effect of physicochemical parameters, including the temperature, cleaning time, pH of the cleaning solution, and addition of additives, on the cleaning process was investigated. The membrane performance was evaluated by testing the flux recovery rate and salt rejection before and after the cleaning process. High temperatures (45-50 ℃) resulted in a better flux recovery rate of 71% with more than 80% salt rejection. Equal time for acid and base cleaning 3-3 h presented a 72.43% flux recovery rate with salt rejection above 85%. During acid and base cleaning, the best results were achieved at pH values of 3.0 and 12.0, respectively. Moreover, 0.05% concentration of ethylenediaminetetraacetic acid presented 72.3% flux recovery, while 69.2% flux was achieved using sodium dodecyl sulfate with a concentration of 0.5%; both showed >80% salt rejection, indicating no damage to the active layer of the membrane. Conversely, 0.5% concentration of sodium percarbonate showed 83.1% flux recovery and 0.005% concentration of sodium hypochlorite presented 85.2% flux recovery, while a high concentration of these chemicals resulted in oxidation of the membrane that caused a reduction in salt rejection.

• Nuclear Engineering and Technology
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• 제52권6호
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• pp.1243-1251
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• 2020

Irradiation-induced damage of binderless nanoporous-isotropic graphite (NPIG) prepared by isostatic pressing of mesophase carbon microspheres for molten salt reactor was investigated by 3.0 MeV He⁺ irradiation at room temperature and high temperature of 600 ℃, and IG-110 was used as the comparation. SEM, TEM, X-ray diffraction and Raman spectrum are used to characterize the irradiation effect and the influence of temperature on graphite radiation damage. After irradiation at room temperature, the surface morphology is rougher, the increase of defect clusters makes atom flour bend, the layer spacing increases, and the catalytic graphitization phenomenon of NPIG is observed. However, the density of defects in high temperature environment decreases and other changes are not obvious. Mechanical properties also change due to changes in defects. In addition, SEM and Raman spectra of the cross section show that cracks appear in the depth range of the maximum irradiation dose, and the defect density increases with the increase of irradiation dose.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.817-825
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• 2022

A recent benchmarking effort, under the auspices of the Organization for Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA), has been made to evaluate the current state of modeling and simulation tools available to model fluoride salt-cooled high temperature reactors (FHRs). The FHR benchmarking effort considered in this work consists of several cases evaluating the neutronic parameters of a 2D prismatic FHR fuel assembly model using the participants' choice of simulation tools. Benchmark participants blindly submitted results for comparison with overall good agreement, except for some which significantly differed on cases utilizing a molybdenum-bearing control rod. Participants utilizing more recently updated explicit isotopic cross sections had consistent results, whereas those using elemental molybdenum cross sections observed reactivity differences on the order of thousands of pcm relative to their peers. Through a series of supporting tests, the authors attribute the differences as being nuclear data driven from using older legacy elemental molybdenum cross sections. Quantitative analysis is conducted on the control rod to identify spectral, reaction rate, and cross section phenomena responsible for the observed differences. Results confirm the observed differences are attributable to the use of elemental cross sections which overestimate the reaction rates in strong resonance channels.