• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.8
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• pp.688-693
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• 2001

A series of Fe/CeO$_2$/Fe$_{75}$Co$_{25}$ tunnel junctions (Magnetic Tunnel Junction, MTJ) having CeO$_2$ barrier layers from 30 to 90$\AA$ in thickness were prepared by ion beam sputtering (IBS) method. In order to compare the properties of MTJs, Fe/Al oxide/Fe-Co tunnel junctions were also prepared. Some junctions with a CeO$_2$ barrier layer showed the ferromagnetic tunneling effect and the highest MR ratio at room temperature was 5%. The electric resistance of junctions with a CeO$_2$ barrier layer was higher that that of junctions with an Al oxide barrier. On the other hand, The interface analysis of the Fe/CeO$_2$ bilayer was conducted by means of X-ray photoelectron spectroscopy (XPS). It was found that CeO$_2$ was decomposed to Ce and $O_2$ during sputtering, and Fe was oxidized with these decomposed $O_2$ molecules. The reduction of both electric resistance and MR ratio may be associated with the decomposed Ce in the barrier layer.r.r.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.29-32
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• 2000

Cerium oxide thin film has been proposed as a buffer layer between the ferroelectric film and the Si substrate in Metal-Ferroelectric-Insulator-Silicon (MFIS ) structures for ferroelectric random access memory (FRAM) applications. In this study, CeO$_2$ thin films were etched with Cl$_2$/Ar gas combination in an inductively coupled plasma (ICP). The highest etch rate of CeO$_2$ film is 230 $\AA$/min at Cl$_2$/(Cl$_2$+Ar) gas mixing ratio of 0.2. This result confirms that CeO$_2$ thin film is dominantly etched by Ar ions bombardment and is assisted by chemical reaction of Cl radicals. The selectivity of CeO$_2$ to YMnO$_3$ was 1.83. As a XPS analysis, the surface of etched CeO$_2$ thin films was existed in Ce-Cl bond by chemical reaction between Ce and Cl. The results of XPS analysis were confirmed by SIMS analysis. The existence of Ce-Cl bonding was proven at 176.15 (a.m.u.).

• Journal of Microbiology and Biotechnology
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• v.28 no.12
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• pp.2121-2132
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• 2018

Abnormal melanin synthesis results in several hyperpigmentary disorders such as freckles, melanoderma, age spots, and other related conditions. In this study, we investigated the anti-melanogenic effects of an extract from the microalgae Chlamydomonas reinhardtii (CE) and potential mechanisms responsible for its inhibitory effect in B16F10, normal human epidermal melanocyte cells, and human skin-equivalent models. The CE extract showed significant dose-dependent inhibitory effects on ${\alpha}$-melanocyte-stimulating, hormone-induced melanin synthesis in cells. Additionally, the CE extract exhibited suppressive effects on the mRNA and protein expression of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2. The CE extract also inhibited the phosphorylation of protein kinase A and extracellular signal-related kinase, which function as upstream regulators of melanogenesis. Using a three-dimensional, reconstructed pigmented epidermis model, the CE-mediated, anti-pigmentation effects were confirmed by Fontana-Masson staining and melanin content assays. Taken together, CE extract can be used as an anti-pigmentation agent.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.4
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• pp.825-830
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• 2009

The purpose of this research was to investigate the effects of Calendula officinalis extract (CE) on the activation of murine lymphocytes and macrophages. CE was administered p.o. once a day for 7 days at the concentration of 500 mg/kg. The administration of CE increased the viability of thymocytes, but decreased the viability of splenocytes. Also, CE increased the viability of thymocytes and splenocytes at the concentration of $5{\mu}g$/ml in vitro. The administration of CE did not affect the population of thymic $CD4^+$/$CD8^+$ cells and splenic $CD4^+$/$CD8^+$ cells. Furthermore, the administration of CE enhanced the phagocytic activity of peritoneal macrophages, but decreased the phagocytic activity in vitro. CE decreased the production of nitric oxide from peritoneal macrophages in vivo and in vitro system. These results suggest that CE enhance of cell viability by a direct influence on thymocytes and phagocytic activity by an indirect influence on peritoneal macrophages.

• Honam Mathematical Journal
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• v.45 no.3
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• pp.397-409
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• 2023

Let R be an associative ring with identity and M be a left R-module. In this paper, we define modules that have the property (δ-CE) ((δ-CEE)), these are modules that have a δ-supplement (ample δ-supplements) in every cofinite extension which are generalized version of modules that have the properties (CE) and (CEE) introduced in [6] and so a generalization of Zöschinger's modules with the properties (E) and (EE) given in [23]. We investigate various properties of these modules along with examples. In particular we prove these: (1) a module M has the property (δ-CEE) if and only if every submodule of M has the property (δ-CE); (2) direct summands of a module that has the property (δ-CE) also have the property (δ-CE); (3) each factor module of a module that has the property (δ-CE) also has the property (δ-CE) under a special condition; (4) every module with composition series has the property (δ-CE); (5) over a δ-V -ring a module M has the property (δ-CE) if and only if M is cofinitely injective; (6) a ring R is δ-semiperfect if and only if every left R-module has the property (δ-CE).

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.313-316
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• 2009

Synthesis of porous $CeO_2$ particles was investigated using various ionic liquids (ILs) as an effective template. The pore structure and crystalline phase of $CeO_2$ particles was affected significantly by the composition of ionic liquids. The strength of the hydrogen bonds on the anion part of ionic liquid was an essential factor to form the pore architecture of $CeO_2$ particles. Moreover, the length of alkyl group on the cation part of ionic liquid determined the pore size and surface area of $CeO_2$ particles. Among the ionic liquids, it was found that 1-Buthyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) was the most effective ionic liquid to synthesize the porous $CeO_2$ particle.

• Journal of the Korean Chemical Society
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• v.28 no.2
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• pp.102-108
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• 1984

The catalytic oxidation of CO has been investigated on $ZnCe_{1+y}O_2$ at temperatures from 300 to $500^{\circ}C$ under various P_{CO} and PO_2 conditions. The oxidation rates have been correlated with 1.5-order kinetics: first order with respect to CO and 0.5 order with respect to O2. CO appears to be absorbed essentially on the O lattice of $ZnCe_{1+y}O_2$ as a molecular species, while $O_2$ adsorbs on an O vacancy as an ionic species. The conductivity data show that CO adsorption contributes electron to the conduction band and the adsorption process of $O_2$ withdraws it from an O vacancy. The oxidation mechanism and the defect model of $ZnCe_{1+y}O_2$ are inferred at given temperature and $PO_2'$s from the agreement between the conductivities and kinetic data. It is suggested that CO absorption is the rate-controlling.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.251-254
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• 2001

This paper describes an efficiency improvement of buried contact solar cell (BSCS) with a structure of MgF$_2$/CeO$_2$/Ag/Cu/Ni grid/n$^{+}$ emitter/p-type Si base/p$^{+}$/Al. Theoretical and experimental investigations were performed on a double layer antireflection (DLAR) coating of MgF$_2$/CeO$_2$. We investigated CeO$_2$ films as an AR layer because they have a proper refractive index of 2.46 and demonstrate the same lattice constant as Si substrate. An optimized DLAR coating shewed a reflectance as low as 2.04 % in the wavelengths ranged from 0.4 ${\mu}{\textrm}{m}$ to 1.1 ${\mu}{\textrm}{m}$. BCSC cell efficiency was improved from 16.2 % without any AR coating to 19.9 % by employing DLAR coatings. Further details on MgF$_2$/CeO$_2$ DLAR coatings on the BCSC cells are presented in this paper.per.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.261-265
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• 2013

Scutellaria barbata D. Don (S. barbata), a traditional Chinese medicine, is used to treat cancers, inflammation, and urinary diseases. This study aimed to determine any protective effects of S. barbata crude extract (CE-SB) against rat liver tumorigenesis induced by diethylnitrosamine (DENA). Liver malfunction indices in serum were measured by biochemical examination. Hematoxylin and eosin staining was performed to examine liver pathology. Contents of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured in liver homogenates to evaluate oxidative stress. The levels of liver malfunction indices in the CE-SB groups, especially in the CE-SB high dose group, were lower than that of the model group (P<0.05). The results from histological examination indicated that the number of liver nodules in the CE-SB groups decreased compared with the model group (P<0.05). Content of MDA determined in liver was significantly decreased, and level of SOD elevated by CE-SB. CE-SB can inhibit experimental liver tumorigenesis and relieve hepatic injury in rats.

• Korean Journal of Poultry Science
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• v.24 no.3
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• pp.139-143
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• 1997

This experiment was conducted to investigate the effect of dietary supplemental charcoal(CH) or charcoal extract(CE) on performance and meat quality of broiler chicks for 5 weeks. Basal diets based on corn and soybean meal contained 21% crude protein for the first 3 weeks and 19% for the rest two weeks. Two levels of dietary CH(O, 0.5%) and CE(0, 0.2%) were fed in a factorial design. There were four replicates of 10 chicks each per treatment. An increased growth rate was observed in chicks fed the basal diet supplemented with CE alone. Chicks fed the diet containing both CH and CE tended to depress the growth rate. Dietary supplemental CH and CE improved the feed conversion efficiency compared to the control group, but was not significantly different between them. The abdominal fat(%) of chicks fed CH alone or both CH and CE tended to de-crease without significant difference. The total lipid content of breast meat of chicks fed CE alone showed significant difference among treatments (P