• Macromolecular Research
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• 제17권11호
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• pp.907-911
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• 2009

To improve the moisture stability of the $CaS:Eu^{2+}$ red phosphor, surface coatings with silica nanoparticles were performed using five different methods, i.e., $P_1$, $P_2$, $P_3$, $P_4$, and $P_5$. The phosphors were coated with silica nanoparticles using a dip coating method ($P_1$) and sol-gel method ($P_2$). The phosphors were coated using a solution containing silica nanoparticles and poly(1-vinyl-2-pyrrolidone), PVP, $(P_3$). The phosphors were also coated with silica nanoparticles by reacting with the 1-vinyl-2-pyrrolidone (VP) monomer ($P_4$) or by reacting with mixtures containing VP and tetraethylorthosilicate ($P_5$). A decrease in the photoluminescence (PL) intensity was observed regardless of the coating methods. However, the moisture stability of the phosphors was enhanced by the coating when aged in a temperature-controlled humidity chamber. Among these methods, the $P_4$ (or $P_5$) method exhibited the greatest increase in moisture stability of the phosphors. The coated phosphors showed a relatively constant intensity with aging time, whereas the uncoated phosphor showed a decrease.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 춘계 학술기술논문발표대회 논문집
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• pp.77-80
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• 2005

The surface of concrete tiles is weak in moisture that it occurrenced efflorescence, but in the former study we found that it is possible to ensure moisture stability of concrete surface by autoclaving. So this study is to discuss the moisture stability and Physical Properties of high-strength glossy concrete according to time and temperature of autoclave curing. As the results, by increasing time and temperature of autoclave curing, compressive strength and surface hardness increased and glossiness decreased. In the case to 3 hour and $180^{\circ}C$ of autoclave curing, there is not effloescences in mosture stability test.

• Journal of Pharmaceutical Investigation
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• 제38권3호
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• pp.157-162
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• 2008

The aim of the study was to formulate the stable amlodipine maleate tablet by selecting and combining of suitable ingredients. Amlodipine tablets were designed by using different manufacturing methods or formulations. Dissolution rate at 30 min of newly formulated tablets was over 98% in 0.1 M HCl medium. After 4 months storage under accelerated condition, the changes of appearance, loss on drying, content and total impurity were investigated. For long-term stability tests, two formulations of K017 (direct compressed tablets consisting of microcrystalline cellulose and pregelatinized starch) and K018 (wet granulated tablets by OpadryAMB) were stored under $25^{\circ}C$, 60% RH for 24 months. Under the accelerated condition, moisture content in K017 formulation was increased as 5.96% for 4 months, while other formulations with anhydrous monobasic phosphoric potassium or by wet granulation showed higher increase in moisture content compared to K017. In addition, K017 formulation showed a low decrease in contents and total relative substance as 0.8% and 0.7%, respectively. Similar stability of amlodipine in K017 was obtained under the long-term stability test. These results indicate that the K017 combined with microcrystalline cellulose and pregelatinized starch as ingredients is very stable formulation to protect active substance from moisture contact and sustain stability. Therefore, suitable combination of ingredients such as microcrystalline cellulose and pregelatinized starch could attribute to enhance the stability of moisture-labile drug such as amlodipine maleate.

• 한국분말재료학회지
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• 제27권3호
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• pp.241-246
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• 2020

To develop Gastrodia elata (GE)-loaded particles for herbal extract dosage forms, various GE-loaded particles containing dextrin, isomalt, maltodextrin, and silicon dioxide as solidifying carriers in the GE water extract are prepared using the spray drying method. Their physical properties are evaluated using the repose angle, Hausner ratio, Carr's index, weight increase rate at 40℃/75% RH condition, and scanning electron microscopy (SEM). Particles made of dextrin improve the fluidity, compressibility, and water stability. In addition, 2% silicon dioxide increases the fluidity and moisture stability. The best flowability and compressibility of GE-loaded particles are observed with TP, dextrin, and silicon dioxide amounts in the ratio of 6/4/0.2 (34.29 ± 2.86°, 1.48 ± 0.03, and 38.29 ± 2.39%, repose angle, Hausner Ratio, and Carr's index, respectively) and moisture stability with a 2% weight increase rate for 14 h at 40℃/75% RH condition. Therefore, our results suggest that the particles prepared by the spray drying method with dextrin and 2% silicon dioxide can be used as powerful particles to improve the flowability, compressibility, and moisture stability of GE.

• 상하수도학회지
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• 제29권1호
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• pp.107-122
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• 2015

The purpose of this study is to analyze the structural stability of pavement due to water infiltration at the road with infiltration trench as using the FEM(finite element analysis). Five cases for FEM is divided considering the amount of rainfall and rain duration time. The results of FEM show that the more rainfall in a short period time is faster the change of moisture content. Also, it is the proportional relationship between and changing area of moisture content of more than 40% due to rainfall. Case 3 and 4 are necessary to check the installation of infiltration trench because of moisture content of more than 40%, recovery time of initial moisture content, and changing area of more than 40%. Case 1,2, and 5 have no a significant effect on road pavement structure due to lower moisture content and shorter duration time of higher moisture content.

• Asian-Australasian Journal of Animal Sciences
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• 제28권6호
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• pp.816-826
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• 2015

The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR). The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted to 400 g/kg (low moisture level, LML), 450 g/kg (medium moisture level, MML), and 500 g/kg (high moisture level, HML), and both non-fermented and 56-d-fermented TMR were subjected to air exposure to determine aerobic stability. Aerobic deterioration resulted in high losses of nutritional components and largely reduced dry matter digestibility. Non-fermented TMR deteriorated during 48 h of air exposure and the HML treatment was more aerobically unstable. On dry matter (DM) basis, yeast populations significantly increased from $10^7$ to $10^{10}cfu/g$ during air exposure, and Candida ethanolica was the predominant species during deterioration in non-fermented TMR. Fermented TMR exhibited considerable resistance to aerobic deterioration. Spoilage was only observed in the HML treatment and its yeast population increased dramatically to $10^9cfu/g$ DM when air exposure progressed to 30 d. Zygosaccharomyces bailii was the sole yeast species isolated when spoilage occurred. These results confirmed that non-fermented and fermented TMR with a HML are more prone to spoilage, and fermented TMR has considerable resistance to aerobic deterioration. Yeasts can trigger aerobic deterioration in both non-fermented and fermented TMR. C. ethanolica may be involved in the spoilage of non-fermented TMR and the vigorous growth of Z. bailii can initiate aerobic deterioration in fermented TMR.

• Advanced Composite Materials
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• 제17권4호
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• pp.359-372
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• 2008

The moisture absorption behavior of carbon fiber-reinforced plastic (CFRP) and its effect on dimensional stability were examined. Moisture diffusivity in CFRP was determined by measuring a specimen's weight during the moisture absorption test. Three types of CFRP specimens were prepared: a unidirectionally reinforced laminate, a quasi-isotropic laminate and woven fabric. Each CFRP was processed into two geometries - a thin plate for determination of diffusivity and a rod with a square cross-section for the discussion of two-dimensional diffusion behavior. By solving Fick's law expanded to 3 dimensions, the diffusivities in the three orthogonal directions were obtained and analyzed in terms of the anisotropy of CFRP moisture diffusion. Coefficients of moisture expansion (CMEs) were also obtained from specimen deformation caused by moisture absorption. During moisture absorption, the specimen surfaces showed larger deformation near the edges due to the distribution of moisture contents. This deformation was reasonably predicted by the finite element analysis using experimentally determined diffusivities and CMEs. For unidirectional CFRP, the effect of the fiber alignment on CME was analyzed by micromechanical finite element analysis (FEA) and discussed.

• 펄프종이기술
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• 제43권3호
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• pp.11-20
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• 2011

The conditions to which pulp fibers are exposed during paper production, converting, storage, use, and recycling can induce various changes in fiber morphology, surface characteristics, and suitability for paper production by recycled fibers. Most of those changes can be described by hornification. Paper has highly hygroscopic properties which affect dimensional change by relative humidity variation of surrounding condition. The purpose of this study was to investigate the dimensional stability, moisture contents and dip elongation of handsheets at different relative humidity conditions of recycled kraft pulp and BCTMP. By using recycled fibers, dimensional stability was increased because hygroscopic properties of fibers decreased with repeated recycling treatment. Dip elongation of recycled pulp was higher than that of virgin pulp because of its weak fiber-to-fiber bonding. By recycling pulp, the relative bonded area was decreased because fiber could not swell more than virgin pulp. Dimensional stability largely depended on the equilibrium moisture contents of paper, the fiber-to-fiber bonding strength, and the relative bonded area.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.465-468
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• 2005

This Study is concerned workability and the physical properties for practical use of waste concrete powder originated from the manufacturing progress of waste concrete aggregate and it apply to concrete tile. Also because it is important that concrete tile has to ensure the surface moisture stability, for solving the problems aplied curing method is air-dried and autoclave curing. As the result, the physical properties, such as fluent properties, compressive strength, surface hardness and surface glossiness, were decreased with increase of replacement ratio of waste concrete powder, also surface stability was weaked about moisture. But by autoclave curing, it is possible that compressive strength and surface hardness increased, and surface moisture stability is ensured.

• Structural Engineering and Mechanics
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• 제56권6호
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• pp.1041-1061
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• 2015

The influence of hygrothermal effects on the vibration frequency and buckling load of a shear deformable composite plate with arbitrary initial stresses was investigated. The governing equations of the effects of humid, thermal and initial stresses are established using the variational method. The material properties of the composite plate are affected by both temperature and moisture. The initial stress is taken to be a combination of uniaxial load and pure bending in a hygrothermal environment. The influence of various parameters, such as the fiber volume fraction, temperature, moisture concentration, length/thickness ratios, initial stresses and bending stress ratio on the vibration and stability of the response of a laminated plate are studied in detail. The behavior of vibration and stability are sensitive to temperature, moisture concentration, fiber volume fraction and initial stresses.