• Journal of the Korean Chemical Society
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• v.43 no.3
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• pp.302-306
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• 1999

The 1,3-dipolar cycloaddition reaction of the quinoxaline 4-oxide 10 with 2-chloroacrylonitrile gave the 2,3-dihydro-lH-1,2-diazepino[3,4-blquinoxalines lla, b, respectively, which were converted into the 2,3,4,6-tetrahydro-lH-l,2-diazepino[3,4-b]quinoxaline 12. The reaction of compound lla with selenium dioxide in acetic acid/water resulted in ring transformation to give the 1,4-dihydro-4-oxopyridazino[3,4-blquinoxaline 13.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.3
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• pp.179-186
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• 2003

This pot experiment was conducted to find out the effects of boron application( $B_{0}$ ) ; control, B$_1$; 0.2, $B_2$; 2.0, $B_3$; 6.0, $B_4$; 15.0 boron me/pot) on the forage performance of pure and mixed cultures of orchardgrass and white clover. The fourth part was concerned with the changes in the contents of B, Fe, Mn, Cu, and Zn in forages. The results obtained are summarized as follows: 1. The boron(B) contents of both forages and their differences among the B treatments generally decreased according to the cutting order. The B contents of white clover were somewhat lower in the $B_{0}$ than in the $B_2$. However, the differences in the yields between $B_{0}$ and $B_2$ were relatively great. It was probably caused by the latent B-deficiency in the $B_{0}$. Compared with white clover, the B contents of orchardgrass had relatively great differences between the $B_{0}$ and B$_2$, but both yields tended to be similar. 2. The contents of Fe, Mn, Cu, and Zn in both forages were generally different according to the forage species, whether it was a pure or mixed cultures, and additional fertilization. The effects of B application on their contents were different according to the micronutrients and above factors. 3. The Fe contents of white clover were lower in the $B_{0}$ and $B_4$ than in the$ B_2$. It tended to be related to the weak growth of roots and low yields in the $B_{0}$ and $B_2$. However, there were not consistent in the changes of contents of Mn, Cu, and Zn by the rates of B application. 4. The effects of B application on the total ion concentrations of Fe, Mn, Cu, and Zn were not consistent in both forages. However, the concentrations were generally affected by the changes in the contents of Mn and Zn. The concentrations of white clover were higher in a pure than in mixed culture.

• Journal of the Korean Ceramic Society
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• v.31 no.5
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• pp.552-560
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• 1994

A composite of TiB2-Al2O3 system was successfully prepared from a mixture of TiO2, B2O3, and Al by self-propagating high temperature synthesis (SHS) with a novel characteristic, utilizing the internal oxidation heat of aluminium metal of the mixture, instead of by a conventional technique, externally heating a mixture of Ti, B and Al2O3. From a mixture with B/Ti molar ratio of =2.0, pure two phases of TiB2 and $\alpha$-Al2O3 with good crystallinity and small, uniform sizes were formed. However, when the B/Ti molar ratio of the mixture goes to a value less than 2.0, in addition to the above main minerals, a small smounts of metastable phases such as TiB and Ti3B4 were formed. It was found that about 60%, the optimum green density of compacts gave their highest reaction rate and temperature during SHS process. TiB2-Al2O3 system composite with B/Ti molar ratio of =2.0 could be pressurelessly sintered even at 190$0^{\circ}C$ under Ar gas flows without any addition of sintering aids, showing their good properties such as 91.2% in relative density, 2750 kgf/$\textrm{mm}^2$ in Vickers hardness and 2620 kgf/$\textrm{cm}^2$ in flexural strength.

• Journal of applied mathematics & informatics
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• v.28 no.1_2
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• pp.325-331
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• 2010

Let a and b be nonnegative integers with 2 $\leq$ a < b, and let G be a Hamiltonian graph of order n with n > $\frac{(a+b-5)(a+b-3)}{b-2}$. An [a, b]-factor F of G is called a Hamiltonian [a, b]-factor if F contains a Hamiltonian cycle. In this paper, it is proved that G has a Hamiltonian [a, b]-factor if $\delta(G)\;\geq\;\frac{(a-1)n+a+b-3)}{a+b-3}$ and $\delta(G)$ > $\frac{(a-2)n+2{\alpha}(G)-1)}{a+b-4}$.

• Korean Journal of Microbiology
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• v.17 no.4
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• pp.165-178
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• 1979

Phages of Lactobaciilus casei (PLC) isolated from plant drainage were classified and characterized. The results are as follows : 1. On the basis of host range pattern, phages could be divided into 2 groups (PLC-B and PLC-C). PLC-B group phages could be further divided into 5 sub-groups $(B_1, \;B_2, \;B_3, \;B_4, \;and\;B_5)$. Although PLC-C group phages had the same host range, they could be also divided into 2 sub-groups $(C_1\;and\;C_2)$ by morphlogical type. 2. It was $B_3$ group phages that represented a major proportion (44.4%) of phages tested. However, $B_1$ group phages were shown to have the widest host range. 3. Electron micrographs revealed that the phages fell into three different morphological types. $(B_1, \;B_2, \;and\;B_3)$ group phages hd a hexagonal head (52nm in diameter) and a sheathless noncontractile (245 nm in length). $B_4\;and\;C_2$ group phages had a hexagonal head (56 nm) and a short flexible tail (169nm) having no sheath. $B_5\;and\;C_1$ group phages were shown to have a hexagonal head (81 nm) and a contractile tail (140 nm) having a sheath, a base plate and tail fibers. 4. The inactivation of the phages by antisera indicated that serological relationships correlated completely with morphological types. 5. $B_1, \;C_1\;and\;C_2$ group phages produced a large (1, 2 mm in diameter) plaque with a clear ring. The morphology of plaques of $B_3\;and\;B_5$ group phages was the same as those produced by the above, but the average plaque sizes for $B_3\;and\;B_5$ were 0.8 mm abd 0.5 mm, respectively. $B_2\;and\;B_4$ group phages produced a small (0.5 mm) turbid plaque with an irregular edge. 6. The latent period and the average burst size of $B_1\;and\;B_3$ group phages were 90 min and 100, respectively. These phages reuqired calcium ions for their miltiplication. 7. $B_3$ group phages could not be absrobed to R-variant $KC_1$. 8. The order of resistance of phages to heat was $B_2\;>\;B_1, B_4\;and\;B_5\;>\;B_3\;and\;C_2, \;B_5$ group phages were more stable than $B_3$ in various pH values. $C_2$ group phages were more sensitive to UV irradiation than $B_1\;and\;B_3$ group phages. 9. Strains YIT9018 and IAM 1043 were induced by mitomycin C treatment. Phage particles detected in the lysates had a hexagonal head (38 and 49 nm, respectively), but no tail. Any sensitive indicator strain could not be isolated in spite of repaeated trials.

• Food Science of Animal Resources
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• v.26 no.4
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• pp.497-502
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• 2006

The adhesion of 16 bifidobacterial strains, including 10 isolates from Korea infants, to Caco-2 cells and their cell surface hydrophobicity were tested. The results of adhesion and cell surface hydrophobicity of for various bifidobacterial strains were obtained and correlations between adhesion and hydrophobicity were strain-dependent properties. Any correlations between species of tested strains were not observed. Among the tested strains, Bifidobacterim longum D6, B. longum H4, B. thermophilum ATCC 25525, B. suis ATCC 27533, and B. animalis subsp. lactis BB12 had higher adherent properties and B. bifidum B3, B. longum D6, B. longum stronger hydrophobicity, respectively. Due to the strain-dependant correlation between adhesion to Caco-2 cells and cell surface hydrophobicity of bifidobacteria, these results provide a possible method for preliminary selection of bifidobacteria potentially adherent to Caco-2 cells by means of cell surface hydrophobic properties.

• Korean Journal of Materials Research
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• v.14 no.1
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• pp.73-77
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• 2004

The mechanical and electrical properties of $Cu-TiB_2$ composites prepared by hot extrusion and cold drawing according to the variation of $TiB_2$ contents and the size of $TiB_2$ particle have been studied. The experimental results showed that the electrical conductivity was decreased with increasing the $TiB_2$ content, and their tensile strength and hardness increased inversely. In the case of the same content of $TiB_2$ particle, the smaller $TiB_2$ particle, the higher their mechanical properties. The electrical conductivity of $Cu-TiB_2$ composites showed more than 70%IACS. Their yield strength and hardness were more than 120 MPa and HRB 60～70, respectively.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.634-636
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• 2001

“B2B 에서의 XML 보안”에 관해서 현재 많은 연구가 활발히 진행되고 있다. 인터넷상에서 뛰어난 확장성을 가지고 있고, 풍부한 자료구조, 국제적 문자에 대한 탁월한 처리를 가진 XML을 많은 기업들이 B2B(Business to Business)에서 많이 사용하고 있다. 또한 EDI(Electronic data Interchange)에서도 XML을 사용한 문서 교환이 활발하게 이용되고 있다. 하지만 XML에서는 보안에 관한 많은 취약점을 가지고 있는 것이 사실이다. 본 논문은 XML의 보안상의 취약점, XML의 보안에 대한 기술, 그리고 인터넷에서 XML 디지털 인증에 관해 구현하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.827-829
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• 2003

판매 후 구매자에 대한 신속하고 투명한 사후처리는 매우 중요하다. 그러나 B2B에 대한 연구는 주로 효율적인 탐색이나 협상과 관련이 있으며, 사후보증에 대한 것은 찾아보기 힘들다. 여기서는 수주생산환경의 B2B 마켓플레이스에서 판매 후 고객만족을 위한 체계적인 사후보증처리 방안을 제안한다. 관련된 기업과 마켓메이커 사이의 비즈니스 관계에 따라 하자처리, 피드백처리, 그리고 작업의뢰처리로 구분하여 각각의 프로세스를 정의한다.

• Journal of Powder Materials
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• v.22 no.5
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• pp.344-349
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• 2015

$MgB_2$ bulk superconductors are synthesized by the solid state reaction of ($MgB_4$+xMg) precursors with excessive Mg compositions (x=1.0, 1.4, 2.0 and 2.4). The $MgB_4$ precursors are synthesized using (Mg+B) powders. The secondary phases ($MgB_4$ and MgO) present in the synthesized $MgB_4$ are removed by $HNO_3$ leaching. It is found that the formation reaction of $MgB_2$ is accelerated when Mg excessive compositions are used. The magnetization curves of $Mg_1+_xB_2$ samples show that the transition from the normal state to the superconducting state of the Mg excessive samples with x=0.5 and x=0.7 are sharper than that of $MgB_2$. The highest $J_c-B$ curve at 5 K and 20 K is achieved for x=0.5. Further addition of Mg decreases the $J_c$ owing to the formation of more pores in the $MgB_2$ matrix and smaller volume fraction of $MgB_2$.