• Journal of Technologic Dentistry
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• v.34 no.2
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• pp.129-134
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• 2012

Purpose: This study was conducted to investigate the colors of zirconia and veneered ceramics according to the build-up method of veneer porcelain. Methods: The samples were divided into three groups: a group for which a liner was applied to the zirconia surface and dentine coating was built up and burned (Cz1), a group for which the dentine coating was directly built up and burned (Cz2), and a group for which the samples were wash-burned with dentine coating and a dentine coating was built up and burned again (Cz3). The the colors were measured with a Spectrophoto-meter. Results: The average $L^*$ value of the Cz3 group was the highest among the groups at $59.1{\pm}0.5$ (P<0.05), followed by Cz2 at $57.5{\pm}0.8$ and Cz1 at $56.6{\pm}1.3$. The $a^*$ value of Cz3 was negative at $-0.0{\pm}0.0$ and the $a^*$ values of Cz2 and Cz1 were positive at $0.2{\pm}0.1$ and $0.4{\pm}0.0$, respectively (P<0.05). The $b^*$ of Cz1 was the highest at $11.2{\pm}0.6$, followed by Cz3 at $10.8{\pm}0.5$ and Cz2 at $10.5{\pm}0.8$ (P<0.05). Conclusion: Compared to other experimental groups, the Cz3 groups showed the brightest colors with high brightness and relatively low green and yellow levels.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.374.1-374.1
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• 2016

Copper and zinc are well known elements with antibacterial effect. So in this research, Cu and Zn (CZ) nanofibers (NFs) were fabricated by electrospinning method using polyvinylpyrrolidone (PVP) for adjusting viscosity. The CZ/PVP precursor solutions were prepared with copper sulfate pentahydrate, and zinc acetate dihydrate. Distilled water was used for solvent and PVP was used to regulate the viscosity of precursor solution. The CZ/PVP NF composites were obtained by electrospinning method using the precursor solution. The average diameter of obtained CZ/PVP NFs was determined by optical microscopy using Motic image plus 2.0 program and was found to be 490 nm. The chemical environment of the obtained CZ/PVP NF composites was investigated with X-ray photoelectron spectroscopy (XPS). After heating the obtained CZ/PVP NF composites at 353 K, the solvent was removed. The characteristic C 1s, Cu 2p, and Zn 2p core level XPS peaks were observed. After calcination the CZ/PVP NF composites at 873 K in Ar environment for 5 hrs, PVP was decomposed at this temperature and CZ NF was obtained. This was confirmed by decreasing the intensity of C 1s.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2901-2909
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• 2020

Thermal creep is a key property of zircaloy cladding. CZ developed by CGN is a new zircaloy used as PWR fuel cladding. This research is devoted to investigating the thermal creep behavior of CZ and build the thermal creep model of CZ. Twenty internal pressure creep tests were conducted, and the ranges of temperature and Tresca stress were 320-430 ℃ and 70-300 MPa, respectively. Real-time creep data were analyzed by separating primary creep and steady-state creep. Based on Soderberg model and creep test data, CZ thermal creep model is derived. As a whole, the mean value and the standard deviation of P/M of CZ saturated primary creep strain are very close to these from steady-state creep rate, however, the predictive effect of primary creep is less satisfactory. Four conditions, where there exists large deviation between predicted values and test data, are 320 ℃ and 300 MPa, 350 ℃ and 190 MPa, 380 ℃ and 160 MPa, 380 ℃ and 190 MPa, respectively. As primary creep was much smaller than steady-state creep in long-time operation, the thermal creep model built can be applied to predict the thermal creep behavior of CZ cladding.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.47-52
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• 2013

In this study, the catalytic performance and characterization of $Ni/Ce_xZr_{1-x}O_2$ were investigated using an autothermal reforming (ATR) process for hydrogen production. The $Ni/Ce_xZr_{1-x}O_2$ catalysts were prepared using the following methods: the water method (CZ-W), urea water method (CZ-UW) and urea, water and ethanol method (CZ-UWA). The performance of $Ni/Ce_xZr_{1-x}O_2$ catalysts in autothermal reforming of propane for hydrogen production was studied in a fixed-bed flow reactor. Reaction tests were conducted by using a feed of $H_2O/C_3H_8/O_2$=3/1/0.37 and $300{\sim}700^{\circ}C$. The CZ-UW and CZ-UWA catalysts showed higher propane conversion and hydrogen yield than the CZ-W catalyst. The activity test confirmed that the improvement in the water-ethanol catalyst was due to the low level of carbon deposition. SEM showed that the surface carbon consisted of clusters on the used CZ-UW catalyst, which is incontrast to the nano-fiber morphology observed on the used CZ-UWA catalyst. It was found that the amount of carbon deposition depends on the preparation method. Especially the $Ni/Ce_{0.75}Zr_{0.25}O_2$ was showed higher propane conversion and hydrogen yield than the other catalysts. Also TGA showed that the resistance of carbon deposition increase to Co addition.

• Korean Journal of Agricultural Science
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• v.51 no.1
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• pp.87-95
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• 2024

The objective of this study was to investigate the anti-obesity effects of adding Momordica charantia (MC) and Chrysanthemum zawadskii var. latilobum (CZ) extracts to drinking water on obesity-induced mice. A total of 84 eight-week-old C57BL/6N male mice with an initial body weight (BW) of 28.11 ± 1.39 g were used in this study. All treatments were fed a high-fat diet for d 28. Mice were randomly divided into seven drinking treatments (six replicate each treatment) based on the initial BW. Treatments are as follows: control (CON), normal tap water, MC 1, CON with 1% MC aqueous extract, MC 2, CON with 2% MC aqueous extract, CZ 1, CON with 1% CZ aqueous extract, CZ 2, CON with CZ aqueous extract (2%), MCZ 1, CON with 1% MC aqueous extract and 1% CZ aqueous extract, MCZ 2, CON with 2% MC aqueous extract and 2% CZ aqueous extract. During the entire period, the CZ 1, MCZ 1, and MCZ 2 significantly decreased (p < 0.05) gain to feed than CON. The CON significantly higher (p < 0.05) water intake than other treatments on d 0 to 14. The MCZ 1 significantly decreased (p < 0.05) relative (ratio of absolute organ weight to BW) organ weights, including retroperitoneal white adipose tissue (RWAT) weight and inguinal white adipose tissue (IWAT) weight, compared to CON. In conclusion, our study suggests that there was no significant difference in the anti-obesity effects between MC and CZ, and MCZ 1 has synergistic effects by regulating adipose tissue.

• Microbiology and Biotechnology Letters
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• v.50 no.2
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• pp.193-201
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• 2022

Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) are major causes of hospital- and community-acquired infections. The treatment of biofilm-related infections caused by these bacteria is a global healthcare challenge. Therefore, the development of alternative therapeutics is required. An essential oil extracted from Curcuma zedoaria (CZ) Rosc, also known as white turmeric, has been reported to possess various antimicrobial activities. In the present study, we evaluated the antibiofilm activities of an ethanolic extract of the CZ rhizome against MRSA and MSSA. The results showed that the CZ extract with the highest sub-minimum inhibitory concentration (sub-MIC), 1/2 MIC (0.312 mg/ml), significantly inhibited biofilm production by up to 80-90% in both tested strains. Subsequently, we evaluated the ability of the CZ extract to prevent cell-surface attachment to a 96-well plate and extracellular DNA (eDNA) release from the biofilm. The CZ extract demonstrated an inhibitory effect on bacterial attachment and eDNA release from the biofilm biomass. The CZ extract may inhibit biofilm formation by preventing eDNA release and cell-surface attachment. Therefore, this CZ extract is a potential candidate for the development of alternative treatments for biofilm-associated MRSA and MSSA infections.

• Korean Chemical Engineering Research
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• v.58 no.3
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• pp.369-380
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• 2020

Most mono-crystalline silicon ingots are manufactured by the Czochralski (Cz) process. But If there are oxygen impurities, These Si-ingot tends to show low-efficiency when it is processed to be solar cell substrate. For making single-crystal Si- ingot, We need Czochralski (Cz) process which melts molten Si and then crystallizing it with seed of single-crystal Si. For melts poly Si-chunk and forming of single-crystalline Si-ingot, the heat transfer plays a main role in the structure of Cz-process. In this study to obtain high-quality Si ingot, the Cz-process was modified with the process design. The crystal growth simulation was employed with pulling rate and rotation speed optimization. Studies for modified Cz-process and the corresponding results have been discussed. The results revealed that using crystal growth simulation, we optimized the oxygen concentration of single crystal silicon by the optimal design of the pulling rate, rotation speed and melt charge level of Cz-process.

• Journal of the Chungcheong Mathematical Society
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• v.20 no.4
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• pp.535-542
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• 2007

In this paper, we investigate the generalized Hyers-Ulam{Rasssias stability of the following Euler-Lagrange type quadratic functional equation $$f(ax+by+cz)+f(ax+by-cz)+f(ax-by+cz)+f(ax-by-cz)=4a^2f(x)+4b^2f(y)+4c^2f(z)$$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.6
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• pp.265-271
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• 2013

Czochralski (CZ) growth process is one of the most important techniques for growing high quality sapphire single crystal for LED application. In this study, the inductively-heated CZ growth processes for the sapphire crystal of 300 mm length have been analyzed numerically using finite element method. The hot zone structures were modified with the crucible geometry change and the additional insulation layer installed above the crucible. The results show that the solid-liquid interface height decreased from about 80 mm at initial stage to 40 mm after mid-stage due to achieve the growth speed balance. Also the optimal input power of the modified system was similar with the original one due to the compensation effects of the crucible geometry and additional insulation. The crystal temperature grown by the modified CZ grower was increased about 10 K than the original one. Therefore the sapphire crystal of 300 mm height was grown successfully.

• The Journal of Korean Medicine
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• v.26 no.1 s.61
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• pp.1-10
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• 2005

Objective: We examined the antimetastatic effect of Curcuma zedoaria Roscoe (CZ) on pulmonary metastasis of B 16 cells. Methods: For 6 weeks, Zedoariae Rhizoma made from dried CZ were dissolved in distilled water and administered to mice 2 weeks before they were injected with B]6 melanoma cells. Mice were given CZ at doses of 250 and 500 mg/kg, and were compared for lung weight, survival days, and NO production. Results: Intake of CZ throughout the experiment extended the average survival time. Intake after B16 cell injection slightly prolonged survival time, but intake before B]6 cell injection did not influence life span. We examined the effect of CZ on macrophage function by measuring NO production. After the macrophages were given CZ for 6 weeks, the amount of NO generated by the macrophages stimulated with LPS in culture medium increased. NO generated by the macrophages also served as a cytotoxic factor against B16 melanoma cells. B16 melanoma-conditioned medium reduced NO production by macrophages. However, CZ treatment reversed the reduction in NO production by the conditioned medium significantly. Conclusion : These findings may suggest that macrophage function-modulating activity by CZ appears to underlie its antimetastatic activity, which leads to a decrease in the number of lung metastatic surface nodules and the extension of life span.