• Journal of the Korean Electrochemical Society
• /
• v.13 no.4
• /
• pp.264-269
• /
• 2010

$LiNi_{0.5}Mn_{0.3}Co_{0.2}O_2$ active material was prepared by simple-combustion method and investigated as the cathode material for li-ion battery. The structural characterization was analyzed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), respectively. The XRD patterns of $LiNi_{0.5}Mn_{0.3}Co_{0.2}O_2$ sample was indicated a phase of layered hexagonal structure. The size of particles has not uniform diameters ranging from 100 to 300 nm. The electrochemical performance of the $LiNi_{0.5}Mn_{0.3}Co_{0.2}O_2$ was measured by Cyclic Voltammetry and galvanostatics. The $LiNi_{0.5}Mn_{0.3}Co_{0.2}O_2$ shows the discharge capacity of ~162 mAh/g in the range of 2.8 to 4.3 V at the first cycle.

• Restorative Dentistry and Endodontics
• /
• v.45 no.4
• /
• pp.54.1-54.16
• /
• 2020

Objectives: This study aimed to synthesize nanocrystals (NCs) of zinc oxide (ZnO) and calcium ion (Ca²⁺)-doped ZnO with different percentages of calcium oxide (CaO), to evaluate cytotoxicity and to assess the effects of the most promising NCs on cytotoxicity depending on lipopolysaccharide (LPS) stimulation. Materials and Methods: Nanomaterials were synthesized (ZnO and ZnO:xCa, x = 0.7; 1.0; 5.0; 9.0) and characterized using X-ray diffractometry, scanning electron microscopy, and methylene blue degradation. SAOS-2 and RAW 264.7 were treated with NCs, and evaluated for viability using the MTT assay. NCs with lower cytotoxicity were maintained in contact with LPS-stimulated (+LPS) and nonstimulated (-LPS) human dental pulp cells (hDPCs). Cell viability, nitric oxide (NO), and reactive oxygen species (ROS) production were evaluated. Cells kept in culture medium or LPS served as negative and positive controls, respectively. One-way analysis of variance and the Dunnett test (α = 0.05) were used for statistical testing. Results: ZnO:0.7Ca and ZnO:1.0Ca at 10 ㎍/mL were not cytotoxic to SAOS-2 and RAW 264.7. +LPS and -LPS hDPCs treated with ZnO, ZnO:0.7Ca, and ZnO:1.0Ca presented similar NO production to negative control (p > 0.05) and lower production compared to positive control (p < 0.05). All NCs showed reduced ROS production compared with the positive control group both in +LPS and -LPS cells (p < 0.05). Conclusions: NCs were successfully synthesized. ZnO, ZnO:0.7Ca and ZnO:1.0Ca presented the highest percentages of cell viability, decreased ROS and NO production in +LPS cells, and maintenance of NO production at basal levels.

• Clean Technology
• /
• v.18 no.3
• /
• pp.259-264
• /
• 2012

Perovskite-type oxides were successfully prepared using malic acid method, characterized by TG/DTA, XRD, XPS, TEM and $H_2$-TPR and their catalytic activities for the combustion of benzene were determined. Almost of catalyst showed perovskite crystalline phase and 15-70 nm particle size. The $LaMnO_3$ catalysts showed the highest activity and the conversion reaches almost 100% at $350^{\circ}C$. The catalysts were modified to enhance the activity through substitution of metal into the A or B site of the perovskite oxides. In the $LaMnO_3$-type catalyst, the partial substitution of Sr into site the A-site enhanced the catalytic activity in the benzene combustion. In addition, the partial substitution of Co or Cu into site the B-site also enhanced the catalytic activity and the catalytic activity was in the order of Co > Cu > Fe in the $LaMn_{1-x}B_xO_3$ (B = Co, Fe, Cu) type catalyst.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.11C
• /
• pp.1541-1550
• /
• 2004

In this paper, we propose an advanced hardware architecture for fast multi-resolution motion estimation of the video coding standard MPEG-1,2 and MPEG-4 AVC. We describe the algorithm and derive hardware architecture emphasizing the importance of area for low cost and fast operation by using the shared memory, the special ram architecture, the motion vector for 4 pixel x 4 pixel, the spiral search and so on. The proposed architecture has been verified by ARM-interfaced emulation board using Excalibur Altera FPGA and also by ASIC synthesis using Samsung 0.18 m CMOS cell library. The ASIC synthesis result shows that the proposed hardware can operate at 140 MHz, processing more than 1,100 QCIF video frames or 70 4CIF video frames per second. The hardware is going to be used as a core module when implementing a complete MPEG-4 AVC video encoder ASIC for real-time multimedia application.

• The KIPS Transactions:PartB
• /
• v.16B no.2
• /
• pp.123-130
• /
• 2009

Motion estimation (ME) plays an important role in digital video compression. But it limits the performance of image quality and encoding speed and is computational demanding part of the encoder. To reduce computational time and maintain the image quality, integer pel and fractional pel ME methods are proposed in this paper. The proposed method for integer pel ME uses a hierarchical search strategy. This strategy method consists of symmetrical cross-X pattern, multi square grid pattern, diamond patterns. These search patterns places search points symmetrically and evenly that can cover the overall search area not to fall into the local minimum and to reduce the computational time. The proposed method for fractional pel uses full search pattern, center biased fractional pel search pattern and the proposed search pattern. According to block sizes, the proposed method for fractional pel decides the search pattern adaptively. Experiment results show that the speedup improvement of the proposed method over Unsymmetrical cross Multi Hexagon grid Search (UMHexagonS) and Full Search (FS) can be up to around $1.2{\sim}5.2$ times faster. Compared to image quality of FS, the proposed method shows an average PSNR drop of 0.01 dB while showing an average PSNR gain of 0.02 dB in comparison to that of UMHexagonS.

• Journal of the Korean Chemical Society
• /
• v.38 no.3
• /
• pp.186-196
• /
• 1994

Three fully dehydrated partially $Ag^+$-exchanged zeolite A(Ag_4Na_8-A, Ag_6Na_6-A, and Ag_8Na_4-A) were treated at $250^{\circ}C$ with 0.1 torr Rb vapor at 4 h. Their structures were determined by singlecrystal X-ray diffraction methods in the cubic space group $Pm{\bar3}m$ (a = 12.264(4) $\AA$, a = 12.269(1) $\AA$, and a= 12.332(3) $\AA$, respectively) at $22(1)^{\circ}C$, and were refined to the final error indices, R(weighed), of 0.056 with 131 reflections, 0.068 with 108 reflections, and 0.070 with 94 reflections, respectively, for which I > $3\sigma(I).$ In these structures, Rb species are found at three different crystallographic sites; three $Rb^+$ ions per unit cell are located at 8-ring centers, ca. 6.0∼6.8 $Rb^+$ ions are found opposite 6-rings on threefold axes in the large cavity, and ca. 2.5 $Rb^+$ ions are found on three fold axes in the sodalite unit. Also, Ag species are found at two different crystallographic sites; ca. 0.6∼1.0 $Ag^+$ ion lies opposite 4-rings and about 1.8∼4.2 Ag atoms are located near the center of the large cavity. In these structures, the numbers of Ag atoms per unit cell are 1.8, 3.0, and 4.2, respectively, and these are likely to form hexasilver clusters at the centers of the large cavities. The $Rb^+$ ions, by blocking 8-rings, may have prevented silver atoms from migrating out of the structure. Each hexasilver cluster is stabilized by coordination to 6-ring, 8-ring $Rb^+$ ions, and also by coordination to a 4-ring $Ag^+$ ion.

• International Journal of Human Ecology
• /
• v.7 no.2
• /
• pp.85-95
• /
• 2006

The purpose of this study was to examine mothers' ideal and actual parenting behaviors toward their infants in three parenting domains; social, didactic, and limit setting. A total of 264 mothers of young children under age three from Seoul, Korea completed Parental Style Questionnaires (PSQ). Mothers' self report on their ideal and actual parenting were explored as a function of child sex, age, and birth order. As expected, there were significant differences between mothers' ideal and actual behaviors in all three parenting domains: Mothers' ideal behaviors such as social interaction, didactic interaction and limit setting were higher than those of their actual behaviors. For mothers' ideal parenting, results revealed neither significant main effects nor interaction effects. However, the Parenting Domain x Birth-Order 2-way interaction and the Parenting Domain x Child Age 2-way interaction were significant for mothers' actual behaviors. Specifically, mothers reported more social and didactic behaviors with their first-born than later born children, but not for limit setting behavior. It was also found that higher limit setting behaviors were apparent for their 2- and 3-year-old than 1-year old children whereas lower social interactions were found for 3-year-old than for 1-year-old. In light of universality and uniqueness, mothers' parenting behavior toward young children has been discussed.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.23 no.6
• /
• pp.1404-1408
• /
• 2009

Methanol extracts of Rubus Coreanus Miquel (RCM) were found to exhibit apoptosis induction of U937 human histiocytic leukemia cells. Treatment of RCM exerted strong cytotoxicity against U937 human leukemia cells. RCM induced apoptosis of U937 leukemia cells in a dose dependent manner. Nitric oxide (NO) production was increased in RCM-treated RAW264.7 macrophage cell line. RCM increased the p53 and $NF{\kappa}B$ gene and decreased the $I{\kappa}B$ gene expression in U937 cells. RCM also increased the $NF{\kappa}B$ protein expression, but decreased the PCNA and BcL-xL protein expression in cultured U937 cells. These data suggest that RCM are effective on the apoptosis induction of human leukemia cells and anti-cancer properties.

• Biomolecules & Therapeutics
• /
• v.30 no.3
• /
• pp.246-256
• /
• 2022

The present study focused on the potential mechanism of betulin (BT), a pentacyclic triterpenoid isolated from the bark of white birch (Betula pubescens), against chronic alcohol-induced lipid accumulation and metaflammation. AML-12 and RAW 264.7 cells were administered ethanol (EtOH), lipopolysaccharide (LPS) or BT. Male C57BL/6 mice were fed Lieber-DeCarli liquid diets containing 5% EtOH for 4 weeks, followed by single EtOH gavage on the last day and simultaneous treatment with BT (20 or 50 mg/kg) by oral gavage once per day. In vitro, MTT showed that 0-25 mM EtOH and 0-25 µM BT had no toxic effect on AML-12 cells. BT could regulate sterolregulatory-element-binding protein 1 (SREBP1), lipin1/2, P2X7 receptor (P2X7r) and NOD-like receptor family, pyrin domains-containing protein 3 (NLRP3) expressions again EtOH-stimulation. Oil Red O staining also indicated that BT significantly reduced lipid accumulation in EtOH-stimulated AML-12 cells. Lipin1/2 deficiency indicated that BT might mediate lipin1/2 to regulate SREBP1 and P2X7r expression and further alleviate lipid accumulation and inflammation. In vivo, BT significantly alleviated histopathological changes, reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and triglyceride (TG) levels, and regulated lipin1/2, SREBP1, peroxisome proliferator activated receptor α/γ (PPARα/γ) and PGC-1α expression compared with the EtOH group. BT reduced the secretion of inflammatory factors and blocked the P2X7r-NLRP3 signaling pathway. Collectively, BT attenuated lipid accumulation and metaflammation by regulating the lipin1/2-mediated P2X7r signaling pathway.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.263-264
• /
• 2002

The tribological characteristic of several environmentally friendly lubricating base stocks was examined, and the effect of some commonly used additives on th tribological behavior of the lubricating oils was comparatively investigated on a four-ball machine. It has been found that the commercial additives including butene sulfide, wax chloride, zinc dialkyldithiophosphate and ashless P-N type agent helped to improve the friction-reducing and antiwear properties as well as the extreme pressure behavior. Non-toxic nanoscale $(CF)_x$ showed the best friction-reducing ability, though it registered relatively poor extreme pressure properties. The mechanism on friction of nano-scale material is discussed.