• Analytical Science and Technology
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• v.13 no.5
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• pp.558-564
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• 2000

Mononuclear schiff base ligand N,N'-bissalicylidene-1,2-phenylenediamine(BSPD) and binuclear schiff base ligands N,N',N',N'''-tetrasalicylidene-3,3',4,4'-tetraaminodiphenyl-methane (TSTM), N,N',N'',N'''-tetrasalicylidene-3,3'-diaminobenzidine (TSDB) have been synthesized. Proton dissociation constants of the ligands were determined by potentiometric method. The synthesized ligands and complexes formed with Cu(II) ion. These complexes were investigated by cyclic voltammetry and differential pulse voltammetry. The results revealed two step diffusion controlled redox process. The mononuclear complex Cu(II)-BSPD and binuclear complexes $Cu(II)_2$-TSDB and $Cu(II)_2$-TSTM were used in the oxidation reaction of ascorbic acid. The reaction rates were in the order of $Cu(II)_2$-TSTM>$Cu(II)_2$-TSDB>Cu(II)-BSPD, indicating that the binuclear $Cu(II)_2$-TSTM complex had the fastest values.

• Korean Journal of Plant Taxonomy
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• v.39 no.1
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• pp.42-47
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• 2009

In this study, the somatic chromosome of 14 taxa of Korean Galium L. were investigated. Among them were a few taxa for which the somatic chromosome number was determined for the first time. The somatic chromosome numbers of Korean Galium L. were 2n = 22, 24, 44, 48, 66, 72, 77, 88 and so basic chromosome numbers were x = 11 or 12. Those taxa having the basic chromosome number x = 11 showed polyploidy, including diploid, tetraploid, heptaploid, and octoploid. Tetraploid and hexaploid can be observed in those taxa with the basic number x = 12. The eleven taxa reported 11 for the first time are G. spurium var. echinospermon (Wallr.) Hayek (2n = 44), G. gracilens (A. Gray) Makino (2n = 22), G. pogonanthum Franch. & Sav. (2n = 22, 44), G. trachyspermum A. Gray (2n = 22, 44), G. japonicum (Maxim.) Makino & Nakai (2n = 77), G. trifloriforme Kom. (2n = 44), G. dahuricum Turcz. var. dahuricum (2n = 48, 72), G. dahuricum var. tokyoense (Makino) Cufod. (2n = 22), G. kinuta Nakai & Hara (2n=66), G. verum var. trachycarpum for. nikkoense (Nakai) Ohwi (2n = 44), G. verum var. asiaticum for. pusillum (Nakai) M. Park (2n = 44). The taxa with the same chromosome numbers as previously reported ones were G. boreale L. (2n=22) and G. verum var. asiaticum Nakai for. asiaticum (2n = 44). The chromosome number of G. trifidum L. (2n = 22) was different from the previous report. Two infraspecific taxa of G. dahuricum showed differences in their basic chromosome numbers (x = 11 for G. dahuricum Turcz. var. dahuricum and x = 12 for var. tokyoense (Makino) Cufod. The somatic chromosome number for G. dahuricum Turcz. var. dahuricum was found to be 2n = 48 (tetraploid) or 72 (hexaploid), while that of G. dahuricum var. tokyoense (Makino) Cufod. was found to be 2n = 22 (diploid). Therefore, basic chromosome numbers for members of the genus Galium can be used as valuable characters in delimiting infrageneric sections and investigating interspecific relationships.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.189-193
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• 2001

We have characterized physical and electrical properties of W-TiN stacked gate electrode structure with TiN as a diffusion barrier of fluorine. As the $N_2/Ar$ gas ratio increased during sputter deposition, TiN thin films became N-rich, and the resistivity of the films increased. However, the resistivity of W-TiN stacked gate reduced as a result of the crystallization of tungsten with the increase of $N_2/Ar$ gas ratio. On the other hand, tungsten in W-TiN stacked gate structure have the (100)-oriented crystalline structure although TiN films were subjected to annealing at high temperature (600~$800^{\circ}C$). Leakage currents of W-TiN gate MOS capacitors were less than $10^{-7}\textrm{/Acm}^2$ and also were lowered by the order of 2 compared with those of pure W gate electrode.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.451-458
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• 2012

This study was conducted to investigate the characteristic factors which have been influenced on nitrous oxide ($N_2O$) emissions related to the environment change of nitrogen application level, rainfall and temperature during the soybean cultivation at black volcanic ash soil from 2010 to 2011. During the soybean cultivation, the more amount of nitrogen fertilizer applied, $N_2O$ emissions amounts were released much. $N_2O$ emissions with the cultivation time were released much at the first and middle of cultivation with heavy rainfall, but it was released very low until the end of cultivation and drought season. $N_2O$ emissions mainly were influenced by the rainfall and soil water content. The correlation ($r$) with $N_2O$ emissions, soil water, soil temperature and soil EC in 2010 were very significant at $0.4591^{**}$, $0.6312^{**}$ and $0.3691^{**}$ respectively. In 2011, soil water was very significant at $0.4821^{**}$, but soil temperature and soil EC were not significant at 0.1646 and 0.1543 respectively. Also, $NO_3$-N and soil nitrogen ($NO_3-N+NO_4-N$) were very significant at $0.6902^{**}$ and $0.6277^*$ respectively, but $NO_4$-N was not significant at 0.1775. During the soybean cultivation, the average emissions factor of 2 years released by the nitrogen fertilizer application was presumed to be 0.0202 ($N_2O$-N kg $N^{-1}\;kg^{-1}$). This factor was higher about 2.8 and 2 times than the Japan's (0.0073 $N_2O$-N kg $N^{-1}\;kg^{-1}$) value and 2006 IPCC guideline default value (0.0100 $N_2O$-N kg $N^{-1}\;kg^{-1}$) respectively.

• 전자공학회논문지 IE
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• v.43 no.2
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• pp.7-10
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• 2006

A GaN-based metal-insulator-semiconductor (MIS) structure has been fabricated by using $BaTa_2O_6$ instead of conventional oxide as insulator gate. The leakage current o) films are in order of $10^{-12}-10^{-13}A/cm^2$ for GaN on $Al_2O_3$(0001) substrate and in order of $10^{-6}-10^{-7}A/cm^2$ for GaN on GaAs(001) substrate. The leakage current of thses films is governed by space-charge-limited current over 45 MV/cm in case of GaN on $Al_2O_3$(0001) substrate and by Poole-Frenkel emission in case of GaN on GaAs(001).

• Bulletin of the Korean Mathematical Society
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• v.42 no.4
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• pp.777-787
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• 2005

In this paper we study (n + 1)-dimensional compact contact CR-submanifolds of (n - 1) contact CR-dimension immersed in an odd-dimensional unit sphere $S^{2m+1}$. Especially we provide necessary conditions in order for such a sub manifold to be the generalized Clifford surface $$S^{2n_1+1}(((2n_1+1)/(n+1))^{\frac{1}{2}})\;{\times}\;S^{2n_2+1}(((2n_2+1)/(n+1)^{\frac{1}{2}})$$ for some portion (n1, n2) of (n - 1)/2 in terms with sectional curvature.

• Journal of IKEEE
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• v.11 no.4
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• pp.152-157
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• 2007

AlGaN/GaN high electron mobility transistors (HEMTs) were fabricated and the effect of ${N_2}O$ plasma on the electrical characteristics of the devices was investigated. The HEMT exposed to ${N_2}O$ plasma formed by 40 W of RF power in a chamber with pressure of 20 mTorr at a temperature of $200^{\circ}C$, exhibited a reduction of gate leakage current from 246 nA to 1.2 pA by 10 seconds treatment. The current between the two isolated active regions reduced from 3 uA to 7 nA and the sheet resistance of the active layer was lowered also. The variations of electrical characteristics for HEMT were occurred within a short time expose of 10 seconds and the successive expose did not influence on the improvements of gate leakage characteristics and conductivity of the active region. The reduced leakage current level was not varied by successive $SiO_2$ deposition and its removal. The transconductnace and drain current of AlGaN/GaN HEMTs were increased also by the expose to the ${N_2}O$ plasma.

• Journal of the Korean Mathematical Society
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• v.60 no.1
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• pp.213-225
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• 2023

For every n ≥ 2, let ℝⁿ_‖·‖ be Rn with a norm ‖·‖ such that its unit ball has finitely many extreme points more than 2n. We devote to the description of the sets of extreme and exposed points of the closed unit balls of 𝓛(²ℝⁿ_‖·‖) and 𝓛_𝒮(²ℝⁿ_‖·‖), where 𝓛(²ℝⁿ_‖·‖) is the space of bilinear forms on ℝⁿ_‖·‖, and 𝓛_𝒮(²ℝⁿ_‖·‖) is the subspace of 𝓛(²ℝⁿ_‖·‖) consisting of symmetric bilinear forms. Let 𝓕 = 𝓛(²ℝⁿ_‖·‖) or 𝓛_𝒮(²ℝⁿ_‖·‖). First we classify the extreme and exposed points of the closed unit ball of 𝓕. We also show that every extreme point of the closed unit ball of 𝓕 is exposed. It is shown that ext B_{𝓛𝒮(²ℝⁿ‖·‖)} = ext B_{𝓛(²ℝⁿ‖·‖)} ∩ 𝓛_𝒮(²ℝⁿ_‖·‖) and exp B_{𝓛𝒮(²ℝⁿ‖·‖)} = exp B_{𝓛(²ℝⁿ‖·‖)} ∩ 𝓛_𝒮(²ℝⁿ_‖·‖), which expand some results of [18, 23, 28, 29, 35, 38, 40, 41, 43].

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.348-352
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• 2011

In this research, we have synthesized new pendant-type polyurethane polymers by introducing various chromophores with stilbene derivatives in the side-chain of the polymer backbone. The Stilbene monomers, N,N-bis(2-hydroxyethyl) amino-4'-cyanostilbene, N,N-bis(2-hydroxyethyl)amino-4'-methoxy stilbene, N,N-bis(2-hydroxyethyl)amino-4'-acetylstilbene, and N,N-bis(2-hydroxyethyl) amino stilbene, were synthesized by Wittig reaction. Another stilbene monomer, N,N-bis(2-hydroxyethyl)amino-4'-nitrostilbene, was synthesized by Knoevenagel condensation. By the measurement of UV-Vis absorption and Photoluminescence (PL) spectrum, we found that introduction of the electron-withdrawing group as a substituent shifts both UV-Vis and PL spectra to longer wavelength, and the introduction of the electron-donating group results in blue-shift of the spectrum. In case of polymer with $NO_2$ group as a substituent, PL is quenched.

• The Korean Journal of Ecology
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• v.3 no.1_2
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• pp.11-16
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• 1980

Growth analytical and primary productivity experiments of soybean populations were conducted with special references to the development of productive structures and environmental conditions of nitrogen levels $(N_1,\; control:\; N_2,\; 6.67gN/\textrm m^2:\; N_3,\;13.34\textrm {gN/m}^2)$. The maximum amounts in LAI for $N_1,\; N_2\; and\; N_3$ stand were 17.3, 19.0 and 18.5; in total standing grops, 1570, 1785 and 1704gDM/$\m^2$; in total net productions, 543, 648 and 636gDM/$\m^2$, respectively. The maximum CGR attanined were 208, 237 and 272 gDM$\m^2$/week, while the mean EU was 2.55, 2.92 and 2.84% N1, N2 and N3, respectively. The total nitrogen standing quantity attained 53.4, 71.8 and 59.8 gN/$\m^2$ at the maximum standing crop period. The net nitrogen absorption rates showed highly significant differences among nitrogen treatments, i.e., 1.34, 10.77 and 13.22 mg/g/day for $N_1,\; N_2\; and \;N_3$ stand, repsectively.