• Journal of Surface Science and Engineering
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• v.54 no.5
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• pp.238-247
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• 2021

PEO (plasma electrolytic oxidation) was applied to modify the surface of AZ31 magnesium alloy in this study. The mixed solution of sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) was used as the electrolyte, and 0 - 0.05 g/L of Ca-GP (Glycerol Phosphate Calcium salt) was added in the electrolyte as an additive. PEO treatment was conducted at a current density of 30mA/cm² for 5 minutes using a DC power supply. The surface properties were identified by SEM, XRD and surface roughness analyses, and the corrosion resistance was evaluated by potentiodynamic polarization and immersion tests. In addition, the biocompatibility was evaluated by immersion test in SBF solution. As the concentration of Ca-GP was increased, the surface morphology was denser and more uniform, and the amount of Ca and the thickness of oxide layer increased. Only Mg peak was observed in XRD analysis due to very thin oxide layer. The corrosion resistance of PEO-treated samples increased with the concentration of Ca-GP in comparision with the untreated sample. In particular, the highest corrosion resistance was identified at the group of 0.04g Ca-GP through potentiodynamic polarization and immersion tests in saline solution (0.9 wt.%NaCl). During the immersion in saline solution, pH rapidly increased at the beginning of immersion period due to rapid corrosion, and then increase rate of pH decreased. However, the pH value in the SBF temporarily increased from 7.4 to 8.5 during the day, then decreased due to the inhibition of corrosion with HA(hydroxyapatite) formation.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.142-149
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• 2019

Purpose: The purpose of this study is to investigate the changes of osteoclast differentiation inhibition according to the period of precipitation when titanium disks were immersed in Modified simulated body fluid (mSBF). Materials and methods: Titanium alloy (Ti grade III) disks with machined surfaces and anodized surfaces were immersed in distilled water and mSBF, respectively. The immersion periods were 7 days, 14 days, 21 days and 28 days, and the control group was immersed in distilled water for each period. RAW 264.7 cells capable of differentiating into osteoclasts were used to measure the number of adherent cells, the measurement of TRAP activity, and the expression pattern of NFATc1 by western blotting. Results: The degree of inhibition of osteoclast differentiation was found to be statistically significant when the disks were immersed in mSBF for more than 14 days on both machined surfaces and anodized surfaces. There was no correlation between immersion time and cell attachment. When the disks were immersed for more than 14 days, TRAP activity was decreased and NFATc1 expression was inhibited. Futhermore, the decrease in TRAP activity and the inhibition of NFATc1 expression remained unchanged. Conclusion: Immersion of titanium disks in mSBF for more than 14 days can prevent RAW 264.7 cells from differentiating into osteoclasts. Inhibition activity does not change even if the immersion period is for more than 14 days.

• Journal of the East Asian Society of Dietary Life
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• v.7 no.1
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• pp.13-20
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• 1997

This study was designed to determine the effects of protein sources on the curation of gastric ulceration, protein metabolism, and nitrogen balance in rats with gastric ulcer induce by restraint and water immersion stress. After the rats were fed 10% casein diet for 3 weeks, four groups of the rats were forced in 5$\times$5$\times$15cm plexiglass cage. The restraint and water immersion stress was carried at 20$\pm$2$^{\circ}C$ for 8-hour. The other one group(control group) was not exposed to stress. After stress 4 kinds of different diets containing 20% protein were given for 5 days. The protein sources were casein, whey protein, soy protein, gluten. The control group was fed to 10% casein diet. The results were as follows ; the weights of rats were not different among the diet groups During the experiment period follows ; the weights of rats were not different among the diet groups during the experiment period (for 5 days). The ulcer index of rats fed 10% gluten and soy protein diet was significantly higher than those of casein and whey protein diet groups(p<0.05). The level of serum albumin was not significantly different among diet groups. But hematocrit and the level of $\alpha$-amino-N, BU and UUN of plant protein diet groups were higher than animal diet groups, the urinary hydroxyproline of soy protein group was the highest and the whey protein was the lowest. The digestibility and BV of nitrogen of gluten diet group were significantly higher than those of casein and whey protein diet groups(p<0.05). The animal proteins had more curative effects of ulcer than plant animals. The results of this study provide useful information concerning diet therapy for the patients with gastrointestinal diseases and the field of enteral diet materials.

• International Journal of Concrete Structures and Materials
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• v.4 no.2
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• pp.109-112
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• 2010

Part I of this study was devoted to the electrical accelerated chloride diffusion in mortars. In this second part, natural chloride diffusion has been investigated for four types of mortars under exposure to a 0.5 mol/L NaCl solution for a period of up to 35 days. Two different types of sand were used for the production of test samples: siliceous sand (used as a reference) and limestone sand (used in this study). The effect of water to cement ratio and exposure time on the diffusion coefficients of mortars was also investigated. In this study, the total and free chloride content and penetration depth of mortar were measured after immersion, and Fick's second law of diffusion was fitted to the experimental data to determine the diffusion coefficient. Their results show that the use of crushed limestone sand in mortar had a positive effect on the chloride resistance. The apparent diffusion coefficient in all specimens was smaller than that in siliceous sand mortar. However, the chloride penetration of these mortars was increased as exposure time progressed.

• Corrosion Science and Technology
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• v.21 no.2
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• pp.77-88
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• 2022

Schiff base quinazoline derivative viz., 3-((2-hydroxy-3-methoxybenzylidene)amino)-2-methylquinazolin-4(3H)-one (SB-Q), was synthesized in this study. Its corrosion protection impact on mild steel (MS) in 1 M hydrochloric acid solution was examined by performing weight loss measurements. The protective efficacy of SB-Q on MS in 1 M HCl was investigated based on its concentrations, immersion period, and immersion temperature. SB-Q was found to be an efficient inhibitor for the corrosion of MS. Its inhibition efficiency was improved by increasing the concentration of SB-Q to an optimal concentration of 500 ppm. Its inhibition efficacy was 96.3% at 303K. Experimental findings revealed that its inhibition efficiency was increased with increasing immersion time, but decreased with an increase in temperature. The adsorption of SB-Q molecules was followed the Langmuir adsorption isotherm model. The adsorption of the examined inhibitor molecules on the surface of mild steel was studied by density functional theory (DFT). DFT investigation confirmed weight loss findings.

• Corrosion Science and Technology
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• v.23 no.4
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• pp.310-314
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• 2024

The corrosion behavior of high chromium white cast iron was studied in 0.5 mol dm^-3 H₂SO₄ + 0.01 mol dm^-3 HCl solution over time through electrochemical and immersion experiments. Potentiodynamic and potentiostatic polarizations revealed active-passivation transition behavior, with critical current densities observed at -0.27 V_SSE and 0.00 V_SSE, repectively. The former potential showed preferential dissolution of primary γ phases, while the latter one showed preferential dissolution of eutectic γ phases. Immersion tests showed an exponential increase in corrosion rate, with significant acceleration observed around 1000 seconds due to the onset of eutectic γ phase dissolution. Over a 24-hour immersion period, both γ phases exhibited extensive corrosion, leaving carbides largely intact. These findings elucidate distinct corrosion behaviors of high chromium white cast iron in acidic environments, providing critical insights into material performance evaluation. Understanding these mechanisms is essential for predicting the longevity and durability of materials in corrosive conditions, thereby informing better material design and application strategies.

• Advances in materials Research
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• v.4 no.3
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• pp.145-164
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• 2015

Biodegredable and injectable nanocomposites based on polypropylene fumarate (PPF) as unsaturated polyester were prepared. The investigated polyester was crosslinked with three different monomers namely N-vinyl pyrrolidone (NVP), methyl methacrylate (MMA) and a mixture of NVP and MMA (1:1 weight ratio) and was filled with 45 wt% of hydroxyapatite (HA) incorporated with different concentrations of chemically treated natural bone powder (NBP) (5, 10 and 15 wt%) in order to be used in treatment of orthopedics bone diseases and fractures. The nanocomposites immersed in the simulated body fluid (SBF) for 30 days, after the period of immersion in-vitro bioactivity of the nanocomposites was studied through Fourier transform infrared (FTIR), scanning electron microscope (SEM), energy dispersive X-ray (EDX) in addition to dielectric measurements. The degradation time of immersed samples and the change in the pH of the SBF were studied during the period of immersion.

• Korean journal of food and cookery science
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• v.5 no.1
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• pp.63-67
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• 1989

The alkali solution consisting of 5% NaOH, 5% NaCl, 2% Tea is most suitable for making pidan. During the soaking period, the values of pH increased from pH 9.02~ 9.19 to pH 12 in the egg white and increased from PH 6.1 to PH 11.63 in the egg yolk. Quail's egg jelled on the 7th day of immersion and the hen's egg and duck's egg jelled on the 10th day of immersion. The Quail's egg ripened at $25^{\circ}C$ in 30~35 days, and Sunghua crystals were formed at the end of the ripening period The moisture content of pidans decreased by 3.5~4.0%, but relatively crude protein, crude fat and crude ash increased by 1.0%, 1.9% and twice respectively. The content of Ca in the hen's pidan and quail's pidan increased about 40%, that of K in the duck's pidan increased about 13% and that of Mg in the hen's pidan and duck's pidan increased about 23~28%. The content of Na in the 3 groups all increased approximately 7 times. The content of total cholesterol level in pidan yolks decreased by 21~40% in each pidan. As a result of a sensory evaluation, the white hen's pidan was most agreeable in flavor and the quail's pidan was most agreeable.

• Journal of the Semiconductor & Display Technology
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• v.5 no.2 s.15
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• pp.37-39
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• 2006

We employed in-situ spectroscopic ellipsometry(SE) and imaging ellipsometry(IE) to study the interaction of water and photoresist(PR) in 193 immersion lithography. Real time measurement of SE showed thickness increase when PR was immerged in water indicating swelling effect. From the temporal evolution we could observe its reaction-limited behavior. Meanwhile, IE could identify the modification of PR surface by contact of water even for a short period of a second.

• Fashion & Textile Research Journal
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• v.12 no.3
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• pp.327-337
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• 2010

The current study investigates e-CRM, Shopping-mall Image, Perceived Value, Immersion, Satisfaction, Purchase Intention in the Fashion e-Commerce. The e-CRM(Customer Relationship Management) was applied to see the effect on the relation quality toward the fashion shopping-mall via relation performance. To fulfill the study objectives, a total of 521 questionnaires(Korean 278 vs, American 243) were conducted to the customers with first-hand experience with fashion merchandise in Internet shopping-mall. The judgement sampling method was employed on sample population ages from 20s to 40s over two month period. The result showed that purchase intention of an individual differs by consumer type and different factors affect purchase intention of the fashion merchandise for each consumer type.