• Journal of Food Hygiene and Safety
• /
• v.24 no.1
• /
• pp.46-49
• /
• 2009

The desmutagenic activity of the water extract of Cassia tara L on the mutagenicity induced by 4-nitroquinoline 1-oxide (4-NQO) and N-methyl-N-nitro-N'-nitrosoguani-dine (MNNG) was studied using the SOS Chromotest with Escherichia coli PQ37. The inhibition rates of water extract of Cassia tara L. at concentration of $100{\mu}g$/assay were 27.5% and 40% against 4-NQO and MNNG. The water extract of Cassia tara L. was separated into methanol soluble and methanol insoluble parts. The methanol soluble part exhibited higher inhibition effects than the methanol insoluble part against the mutagenic activities of 4-NQO and MNNG. Step-wise fractionation of methanol soluble part was done to obtain methanol, ethyl acetate and water fractions. Among these fractions, water fraction had the strongest inhibitory effects of 23.0 and 19.0% against mutagenicities of MNNG and 4NQO, respectively. The results clearly indicated that the water fraction showed much stronger antimutagenicity against MNNG than 4NQO. The inhibition rates of aqueous fraction of methanol-soluble from water extracted Cassia tara L. at concentrations of 1.0, 10, 100 and $250{\mu}g$/assay were 8.0%, 12.0%, 25.5% and 43.0%, respectively. The water fraction showed the inhibitory effects with dose response against the mutagenic activities induced by MNNG.

• Journal of the Korean institute of surface engineering
• /
• v.35 no.3
• /
• pp.133-140
• /
• 2002

The Ti-Si-N coating layers were synthesized on SKD 11 steel substrate by a DC reactive magnetron co-sputtering technique with separate Ti and Si targets. The high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analyses for the coating layers revealed that microstructure of Ti-Si-N layer was nanocomposite, consisting of nano-sized TiN crystallites surrounded by amorphous $Si_3$$N_4$ phase. The highest hardness value of about 39 GPa was obtained at the Si content of ~11at.%, where the microstructure had fine TiN crystallites (about 5nm in size) dispersed uniformly in amorphous matrix. As the Si content in Ti-Si-N films increased, the TiN crystallites became from aligned to randomly oriented microstructure, finer, and fully penetrated by amorphous phase. Free Si appeared in the layers due to the deficit of nitrogen source at higher Si content. Friction coefficient and wear rate of the Ti-Si-N coating layer significantly decreased with increase of relative humidity. The self-lubricating tribe-layers such as $SiO_2$ or (OH)$Si_2$ seemed to play an important role in the wear behavior of Ti-Si-N film against steel.

• Bulletin of the Korean Chemical Society
• /
• v.4 no.3
• /
• pp.139-143
• /
• 1983

${\beta}$-N-Acetyl-D-glucosaminidase B was highly purified with the following sequence of steps; DEAE-cellulose, CM-cellulose, and Sephadex G-200 gel filtration chromatograpies. The specific activity of the purified ${\beta}$ -N-acetyl-D-glucosaminidase B was 2.2 units/mg protein with 12.9 % yield and 196.2 fold purity. The purified ${\beta}$-N-acetyl-D-glucosaminidase B showed single band on polyacrylamide gel electrophoresis. The final preparation of ${\beta}$ -N-acetyl-D-glucosaminidase B was completely free friom arylsulfatase and ${\beta}$-glucuronidase. ${\beta}$ -N-Acetyl-D-glucosaminidase B had pH optimum of 4.5 in 0.5 M sodium citrate buffer. The molecular weight of ${\beta}$-N-acetyl-D-glucosaminidase B was 133,000 by Sephadex G-200 gel filtration. The Km value of ${\beta}$-N-acetyl-D-glucosaminidase B using p-nitrophenyl-N-acetyl-${\beta}$-D-glucosaminide as substrate was 1.0 mM and $V_{max}$ was 0.014 ${\mu}$ mole/min. ${\beta}$-N-Acetyl-D-glucosaminidase B was stable at $55^{circ}C$ for 70 minutes. The crude ${\beta}$ -N-acetyl-D-glucosamiinidase in 70 % ammonium sulfate retained 93 % activity after 7 months storage at -$55^{circ}C$. Bovine serum albumin, sodium chloride, and phosphate activated ${\beta}$ -N-Acetyl-D-glucosaminidase B. N-Acetyl-D-glucosamine, ${\alpha}$-methyl-D-mannoside, and acetate inhibited ${\beta}$ -N-acetyl-D-glucosaminidase B.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.331-334
• /
• 2001

In this study, the magnetic properties for Ni-Zn ferrite were investigated as the function of $Co_3$ $O_4$ additive contents which was predicted to improve the resonance frequency. Toroid specimens with the composition of N $i_{0.8-x}$Z $n_{0.2+x}$F $e_2$ $O_4$(x = 0, 0.05, 0.1, 0.15) ferrites were preparation by conventional ceramic processing technique. The maximum resonance frequency of 19.905 MHz and the permeability of 90.88 in 10 MHz were attained to the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$with $Co_3$ $O_4$0.3 wt%. Both of the permeability in 10 MHz and the resonance increased to 107.11 and 19.005 MHz respectively for the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$with $Co_3$ $O_4$wt% than the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$/ with the free $Co_3$ $O_4$composition.composition.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.1B
• /
• pp.93-100
• /
• 2011

The people frequently drink coffee under stress at work, according to increase attractive of leisure activities, favourite food in modern society. The coffee taste which we are catching the taste of modern people is depending on various kinds processing methods such as a mixture of beans. However, the most coffee contains $C_8H_{10}O_2N_4$ which affected various parts of the body. These $C_8H_{10}O_2N_4$, is that the main component of coffee is caffeine. Therefore, in this paper, we are analyzed influence about articulator according to increase in $C_8H_{10}O_2N_4$ 250mg contains a cup of coffee. From this, we gradually increased the amount of $C_8H_{10}O_2N_4$ intake about thirty persons of men in his 20's in experiments. Then we performed a study about Jitter, Formant, Spectrum in voice analysis parameter by applying the results having an affect articulator.

• Journal of the Korean Chemical Society
• /
• v.45 no.5
• /
• pp.429-435
• /
• 2001

The monomer N,N'-bis(2-pyrrol-1-yl-propyl)-4,4'-bipyridine(bpb) was electrochemically polymerized on the glassy carbon electrode surface, which was modified with 1:1 ratio of erichrome black T(EBT) and glutathione(GSSG) to give a type of GC/poly-bpb, EBT, GSSG electrode for depositing Zn(II). The diffusion coefficients of the incorporated ions were 2.43${\times}10^{-15}$ and 9.14${\times}10^{-15} cm^2s^{-1}$ before taking Zn(II) ions and after them respectively. The modified electrodes are stable at the electrode process. The polymerized poly-bpb of 2.83${\times}10^4gmol^{-1}$ can deposit 2.15${\times}10^4gmol^{-1}$ of Zn(II). The number of pumping ions involving in the redox procedure at 0.77 V was 81.7% of the captured 180 ions into the polymer matrix, which was 3 times larger than that of the electrode modified with EBT alone.

• Applied Chemistry for Engineering
• /
• v.18 no.5
• /
• pp.506-510
• /
• 2007

Vacuum deposited 4,4',4''-tris(N-(1-naphthyl)-N-phenylamino)-triphenylamine (1-TNATA), a widely-used semiconductor material, is placed as a thin interlayer between indium tin oxide (ITO) electrode and a hole transporting layer (HTL) in OLEDs and a well-stacked 1-TNATA layer leads to stable and high efficiency devices by reducing the carrier injection barrier at the interface between the ITO anode and hole transport layers. According to Raman spectra, thermal annealing after deposition as well as electromagnetic field treatment during deposition lead to closer stacking of 1-TNATA molecules and resulted in molecular ordering. By thermal annealing at about $110^{\circ}C$, an increase in current flow through the film by over 25% was observed. Molecularly-ordered 1-TNATA films played an important role in achieving higher luminance efficiency as well as higher power efficiency of the multi-layered organic EL devices in the present work. Electromagnetic field treatment during deposition was less effective compared to thermal annealing

• Journal of the Korean Chemical Society
• /
• v.20 no.6
• /
• pp.479-485
• /
• 1976

The rate of the bromine-exchange reaction between gallium bromide and n-butyl bromide in 1,2,4-trichlorobenzene and in nitrobenzene was measured at 19, 25 and 40$^{\circ}C$., using n-butyl bromide labelled with Br-82. The results indicated that the exchange reaction was second order with respect to gallium bromide and first order with respect to n-butyl bromide. The third-order rate constant determined at $19^{\circ}C.$ is 1.15{\times}10^{-4} l^2{\cdot}mole^{-2}{\cdot}sec^{-1}$ in 1,2,4-trichlorobenzene and $4.21{\times}10^{-4} l^2·$$mole^{-2}{\cdot}sec^{-1}$ in nitrobenzene. The activation energy, the enthalpy of activation and the entropy of activation for the exchange reaction were also determined.

• Journal of the Korean Magnetics Society
• /
• v.16 no.4
• /
• pp.193-196
• /
• 2006

The magnetic properties of Ni nanowires consisting of one to four atoms are investigated by mean of ab initio spin-polarized density functional calculations. Stability of zigzag-square $Ni_4$ nanowire is larger than $Ni_4$ nanowires with square. The magnetic moment of linear $Ni_1$ is $1.34{\mu_B}/atom$, which is the largest magnitude among moments of five Ni nanowires. The magnetic moment of Ninanowires show to be decreased by increasing the number of atoms in unit cell. The smallest moment is $0.91 {\mu_B}/atom$ for square $Ni_4$ nanowire. The spin polarization of zigzag-square $Ni_4$ nanowire is 32% higher than that of fcc bulk Ni.

• Journal of the Korean Chemical Society
• /
• v.47 no.2
• /
• pp.109-114
• /
• 2003

The electronic absorption spectra of trans-$[CrX_2([15]aneN_4)]ClO_4\;([15]aneN_4$=1,4,8,12-tetraazacyclopentadecane; X=F, Cl) complexes have been interpreted using the ligand field theory. An AOMX program is used to optimize the differences between the calculated and the observed positions for the spin-allowed transition bands. The crystal field theory(CFT) parameter is directly related to the angular overlap model(AOM), normalized spherical harmonic hamiltonians(NSH), and semiempirical parameters. The various ligand field parameters are discussed in terms of their chemical significances. According to the ligand field analysis, we can confirm that the fluoride ligand is a very strong ${\sigma}-$ and ${\pi}-$donor while the chloride has weak ${\sigma}-$ and ${\pi}-$donor properties toward chromium(III) ion.