• Bulletin of the Korean Mathematical Society
• /
• v.61 no.2
• /
• pp.291-299
• /
• 2024

We study some factorization properties of the idealization R(+)M of a module M in a commutative ring R which is not necessarily a domain. We show that R(+)M is ACCP if and only if R is ACCP and M satisfies ACC on its cyclic submodules. We give an example to show that the BF property is not necessarily preserved in idealization, and give some conditions under which R(+)M is a BFR. We also characterize the idealization rings which are UFRs.

• Journal of the Korean Chemical Society
• /
• v.58 no.5
• /
• pp.496-499
• /
• 2014

• Communications of the Korean Mathematical Society
• /
• v.23 no.3
• /
• pp.413-420
• /
• 2008

The object of the present paper is to study some properties of a quasi Einstein manifold. A non-trivial concrete example of a quasi Einstein manifold is also given.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2004.07a
• /
• pp.476-476
• /
• 2004

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.04a
• /
• pp.132.2-132
• /
• 2003

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.4
• /
• pp.7-17
• /
• 2002

• Bulletin of the Korean Chemical Society
• /
• v.25 no.4
• /
• pp.511-516
• /
• 2004

A Li$[Co_{0.17}Li_{0.28}Mn_{0.55}]O_2$ cathode compound was prepared by a simple combustion method. The X-ray diffraction pattern showed that this compound could be classified as ${\alpha} -NaFeO_2$ structure type with the lattice constants of a = 2.8405(9) ${\AA}$ and c = 14.228(4) ${\AA}$. According to XANES analysis, the oxidation state of Mn and Co ions in the compound were 4+ and 3+, respectively. During the first charge process, the irreversible voltage plateau at around 4.65 V was observed. The similar voltage-plateau was observed in the initial charge profile of other solid solution series between $Li_2MnO_3\;and\;LiMnO_2$ (M=Ni, Cr...). The first discharge capacity was 187 mAh/g and the second discharge capacity increased to 204 mAh/g. As the increase of cycling number, one smooth discharge profile was converted to two distinct sub-plateaus and the discharge capacity was slowly decreased. From the Co and Mn K-edge XANES spectra measured at different cyclic process, it can be concluded that irreversible transformation of phase is occurred during continuous cycling process.

• Journal of Advanced Marine Engineering and Technology
• /
• v.29 no.5
• /
• pp.495-501
• /
• 2005

Al is a active metal that owes its resistance to a thin, protective, barrier oxide surface layer, which is stable in air and neutral aqueous solution. Thus Al alloys are widely used in architectural trim. cold & hot-water storage vessels and piping. However Al and most of its alloy may corrode with some forms such as pitting corrosion, intergranular corrosion and galvanic corrosion in the case of exposure to various industrial and marine atmosphere. Therefore a correct evaluation of corrosion resistance for their Al and Al alloys may be more important in a economical point of view. In this study. a relative evaluation of corrosion resistance for three kinds of Al alloys such as ALDC2, ALDC3, and ALDC8 series was carried out with electrochemical method. There is a tendency that corrosion potential is shifted to positive or negative direction by alloying components regardless of corrosion resistance. Moreover the data of corrosion properties obtained from cathodic Polarization curve, cyclic voltammogram and AC. DC impedance respectively showed a good correspondence each other against the corrosion resistance but variation of corrosion potential. passivity current density of anodic polarization curve and corrosion current density by Tafel extrapolation and Stern-Geary method didn't correspond with not only each other but also considerably the data of corrosion properties discussed above. Therefore it is suggested that an optimum electrochemical evaluation for corrosion resistance of Al alloy is to calculate the diffusion limiting current density of cathodic polarization curve, impedance of AC or DC and polarization resistance of cyclic voltammogram.

• Korean Journal of Veterinary Research
• /
• v.43 no.4
• /
• pp.615-624
• /
• 2003

Vascular smooth muscle relaxation is modulated by an increase in cGMP subsequent to nitric oxide (NO) production by endothelial cells. The effects of cAMP and cGMP phosphodiesterase (PDE) inhibitors were investigated in phenylephrine-precontracted rat aorta rings by using the specific inhibitors of PDE I, III, IV and V as relaxing agents (calmodulin-activated PDE inhibitors, IBMX and $W_7$, type I; cAMP-specific PDE inhibitors, milrinone, type IV; Ro 20-1724, type III and cGMP-specific PDE inhibitor, zaprinast, type V). All the PDE inhibitors produced a concentration-dependent relaxation in the ring with intact endothelium (+E). Except for milrinone, all the PDE inhibitors-induced relaxations were inhibited by removal of extracellular $Ca^{2+}$, $N^G$-nitro-L-arginine, $N^G$-nitro-L-arginine methyl ester, methylene blue (MS) or nifedipine. The specific PDE I and PDE IV inhibitors both produced endothelium-independent relaxations which were inhibited by MS in -E rings. However, zaprinast had no effect in -E rings. Except for milrinone, sodium nitroprusside (a NO donor)-induced relaxation was significantly augmented by all PDE inhibitors in +E rings. The results suggest that I) the vasorelaxant properties of IBMX, $W_7$, Ro 20-1724 and zaprinast are dependent on endothelium or on interaction with $Ca^{2+}$ regulation, 2) each PDE is differently distributed in vascular tissues (endothelial and smooth muscle cells), 3) the vasodilations of PDE inhibitors are due to the increase of cAMP and cGMP formation through inhibition of cAMP- and cGMP-PDE and 4) the vasodilation action of milrinone does not involve in endothelial-cyclic nucleotide system.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.46 no.6
• /
• pp.16-25
• /
• 2009

In this paper we propose the block based image segmentation method using the cyclic properties of hue components in HSI color model. In proposed method we use center point instead of hue mean values as the hue representatives for regions in image segmentation considering hue cyclic properties and we also use directed distance for the hue difference among regions. Furthermore we devise the simple and effective method to get critical values through control parameter to reduce the complexity in the calculation of those in the conventional method. From the experimental results we found that the segmented regions in the proposed method is more natural than those in the conventional method especially in texture and red tone regions. In the simulation results the proposed method is better than the conventional methods in the in the evaluation of the human segmentation dataset presented Berkely Segmentation Database.