• East Asian mathematical journal
• /
• v.14 no.2
• /
• pp.259-268
• /
• 1998

In this paper, for a commutative ring R with an identity, considering the endomorphism ring $End_R$(M) of left R-module $_RM$ which is (quasi-)injective or (quasi-)projective, some discriminations of prime endomorphism were found as follows: each epimorphism with the irreducible(or simple) kernel on a (quasi-)injective module and each monomorphism with maximal image on a (quasi-)projective module are prime. It was shown that for a field F, any given square matrix in $Mat_{n{\times}n}$(F) with maximal image and irreducible kernel is a prime matrix, furthermore, any given matrix in $Mat_{n{\times}n}$(F) for any field F can be factored into a product of prime matrices.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.4
• /
• pp.428-433
• /
• 1989

The objective of this experiment was to determine if there were feasible to transplant infant rice seedling for machine transplanting. Cultivars tested were Sobaegbyeo and Daecheongbyeo, ]aponica type cultivars. Infant seedling, young seedling and semi-adult seedling were raised with sailor rock wool in seedling tray from 1986 to 1988. Infant rice seedling raised more than 4 days after sowing with rock wool was uniform, and low in ratio of missing hill at machine transplanting. Tiller number per m$^2$ was more in infant rice seedling, young seedling and semi-adult seedling, in that order. Heading dates were not significantly different among seedlings applied, however rice plant sown directly was later 4 or 5 days than any other seedlings. Panicle number per m$^2$ was more in infant seedling than in semi-adult seedling, but ripened ratio was lower in infant seedling due to lodging. Thus there were not greatly different in yield among seedlings tested. Therefore infant rice seedling (more than 5cm in plumule length) raised for 7 days was most optimum, and rock wool would be used as a nursery soil instead of nursery soil for raising infant rice seedling in machine transplanting.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.05a
• /
• pp.142.2-142.2
• /
• 2007

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07a
• /
• pp.256-259
• /
• 2004

Chemical mechanical polishing(CMP) has been adopted in processing semiconductors for more than ten years. Although some customers expressed negative opinion about CMP at the beginning of its appearance, CMP has currently been applied to a variety of fields in addition to semiconductor multi-layer wiring strategies. This report summarizes each sort of CMP skills in their development stage and introduces each type of MAT's machines optimized for CMP research and development

• Proceedings of the Korean Magnestics Society Conference
• /
• 2000.09a
• /
• pp.247-248
• /
• 2000

• Korean Journal of Environmental Agriculture
• /
• v.17 no.2
• /
• pp.150-155
• /
• 1998

To investigate effects of organic matter application on heavy metal uptake of infant rice seeding, the various amount of organic matter(peat and $Bio-com^{(R)}$)was applied on Cd or Cu treated nursery bed soil. No growth difference was observed up to 20mg/kg of Cu treatment. Above 20mg/kg of Cu treatment, the seeding height and top dry weight were decreased but the Cu uptake by seeding was increased with increasing Cu treatment level. The mat formation was poor above 20mg/kg of Cu treatment, however, the seeding peat application level. All peat treatment resulted better mat formation than control. The seeding height and top dry increasing Cd treatment level. The mat formation was not effected by either Cd treatment level or organic matter sources. The effect of peat and $Bio-com{(R)}$ application on Cd uptake by infant rice seeding was not observed at all Cd treatments level.

• Korean Journal of Remote Sensing
• /
• v.21 no.5
• /
• pp.405-415
• /
• 2005

It is difficult to classify tidal flat surface that is composed of a mixture of mud, sand, water and microphytobenthos. We used a Linear Spectral Unmixing (LSU) method for effectively classifying the tidal flat surface characteristics within a pixel. This study aims at 1) detecting algal mat using LSU in the Saemangeum tidal flats, 2) determining a suitable end-member selection method in tidal flats, and 3) find out a habitual characteristics of algal mat. Two types of end-member were built; one is a reference end-member derived from field spectrometer measurements and the other image end-member. A field spectrometer was used to measure spectral reflectance, and a spectral library was accomplished by shape difference of spectra, r.m.s. difference of spectra, continuum removal and Mann-Whitney U-test. Reference end-members were extracted from the spectral library. Image end-members were obtained by applying Principle Component Analysis (PCA) to an image. The LSU method was effective to detect microphytobenthos, and successfully classified the intertidal zone into algal mat, sediment, and water body components. The reference end-member was slightly more effective than the image end-member for the classification. Fine grained upper tidal flat is generally considered as a rich habitat for algal mat. We also identified unusual microphytobenthos that inhabited coarse grained lower tidal flats.

• Bulletin of the Korean Mathematical Society
• /
• v.46 no.6
• /
• pp.1141-1149
• /
• 2009

In this article, we study surfaces of revolution without parabolic points in a Euclidean 3-space whose Gauss map G satisfies the condition ${\Delta}^hG\;=\;AG,A\;{\in}\;Mat(3,{\mathbb{R}}),\;where\;{\Delta}^h$ denotes the Laplace operator of the second fundamental form h of the surface and Mat(3,$\mathbb{R}$) the set of 3${\times}$3-real matrices, and also obtain the complete classification theorem for those. In particular, we have a characterization of an ordinary sphere in terms of it.

• Journal of Veterinary Clinics
• /
• v.21 no.2
• /
• pp.168-171
• /
• 2004

The effects of alterations of dose of xylaznie (X) and Zoltil$\circledR$ (TZ) on canine anesthesia were examined. Experimental groups were divided into three (Group 1: X 1.1 mg/kg and TZ 10 mg/kg, Group 2: X 1.65 mg/kg and TZ 7.5 mg/kg, Group 3: X 2.2 mg/kg and TZ 5 mg/kg), and each had 5 dogs. A femoral artery was catheterized for measurement of blood pressure, and baseline value was measured. The dogs were sedated with xylazine intramuscularly, then after 10 minutes TZ were injected intravenously. Mean arterial blood pressures (MAP), duration of analgesia, mean arousal time (MAT) and mean walking time (MWT) after TZ injection were measured, and the depth of analgesia and the quality of recovery were scored. The values of MAP were recorded from the time of pre-xylazine injection to arousal. Duration of analgesia and was assessed by tail clamping test, and which were done at 10 minutes intervals after TZ injection. The decreases of MAP from 40 minutes after TZ injection were significant (p<0.05). In group 2, MAP at 20 minutes, and from 40 minutes to arousal were significantly decreased (p<0.05). In group 3, MAP were significantly decreased from 40 minutes. MAT were 62.2$\pm$9.2 minutes in group 1, 60.2$\pm$7.5 minutes in group 2, and 71.0$\pm$6.9 minutes in group 3. MAT in group 3 was significantly increased compared with group 2 (p<0.05), and the differences of MWT among each groups were not significant (p>0.05). The scores of quality of recovery were significantly lowered in group 3 compared with group 1 or group 2, which means the side effects of recovery were less occurred. Thus, it was considered that the combination X 2.2 mg/kg IM and TZ 5 mg/kg IV is more effective to surgical procedures and to prevent long and rough recovery of Zoletil anesthesia.

• Journal of Environmental Science International
• /
• v.18 no.10
• /
• pp.1123-1134
• /
• 2009

This study was designed to evaluate qualitatively and quantitatively the pollutant compositions, which were emitted from three types of mosquito repellents(MRs)(mat-, liquid-vaporized, and coil-type) by utilizing a 50-L environmental chamber. A qualitative analysis revealed that 42 compounds were detected on the gas chromatography/mass spectrometer system, and that the detection frequency depended upon chemical types. Nine of the 42 compounds exhibited a detection frequency of 100%. Four aromatic compounds(benzene, ethyl benzene, toluene, and xylene) were detected in all test MRs. The concentration equilibriums in the environmental chamber were achieved within 180 min after sample introduction. The coil-type MR represented higher chamber concentrations as compared with the mat- or liquid-vaporized-type MR, with respect to the target compounds except for naphthalene. In particular, the chamber concentrations of ethyl benzene, associated with the use of coil-type MR, were between 0.9 and $65\;mg\;m^{-3}$ whereas those of mat- and liquid-vaporized-type MRs we~e between 0.5 and $2.0\;mg\;m^{-3}$and 0.3 and $1.4\;mg\;m^{-3}$, respectively. However, naphthalene concentrations in the chamber, where a liquid-vaporized-type MR was placed, were measured as between 17.8 and $56.3\;mg\;m^{-3}$, but not detected in the chamber, where a mat- or coil-type MR was placed. The empirical model fitted well with the time-series concentrations in the environmental chamber(in most cases, determination coefficient, $R^2$ ≿ 0.9), thereby suggesting that the model was suitable for testing emissions. In regards to the target compounds except for benzene, although they were emitted from the MRs, health risk from individual exposure to them were estimated not to be significant when comparing exposure levels with no observed adverse exposure levels or lowest observed adverse exposure levels of corresponding compounds. However, it was concluded that the use of MRs could be an important indoor source as regards benzene.