• Journal of the Korean Vacuum Society
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• v.9 no.3
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• pp.233-236
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• 2000

The structural, electrical and chemical characteristics of Al alloy thin film with low impurity concentrations AlW deposited by using dc magnetron sputtering deposition are investigated for the applications as data bus line in the TFT-LCD panel. The deposited thin films show the decrease of resistivity and the increase of grain size after the RTA at $300^{\circ}C$ for 20 min.. Moreover, the resistivity of AlW does not show appreciable grain size dependence after RTA. It is concluded that the decrease of resistivity after RTA is due to the increase of grain size. The annealed AlW is found to be hillock free. And for investigating chemical attack in TFT-LCD etching processing the electric potential of AlW alloy for Ag/AgCl were investigated by cyclic voltammetry. When W wt.% of AlW alloy was higher than about 3%, the electric potential of AlW was more positive than ITO's. Therefore AlW alloy thin film can be propose to use for data bus line.

• Journal of Electrochemical Science and Technology
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• v.12 no.4
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• pp.431-439
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• 2021

This research work aims to investigate the effect of the aerobic bacterium, Pseudomonas aeruginosa on the mechanical and electrochemical properties of the 316L stainless steel and α-brass. These properties of both the alloys were determined after 7 days of exposure to the controlled and inoculated media at 37℃. The microstructural and electrochemical test results revealed the deleterious effects of Pseudomonas aeruginosa. After exposure to the inoculated medium, the scanning electron microscopy (SEM) results showed the larger pitting and formation of relatively dense biofilm on α-brass compared to 316L stainless steel. The tensile strength and hardness of 316L stainless steel were slightly affected after exposure to the controlled and inoculated media. After exposure to the controlled medium and inoculated media, the tensile strength of the α-brass was least affected but a significant decrease in the hardness (from 165 HV to 124 HV) was observed due to the severe attack induced by the Pseudomonas aeruginosa. Similarly, the open-circuit potential of the 316L stainless steel in the inoculated medium was measured to be less active (-410 mV vs Ag/AgCl) than α-brass (-550 mV vs Ag/AgCl). In the inoculated medium, potentiodynamic polarization curves confirmed the severe attack of Pseudomonas aeruginosa on α-brass (7.15 × 10^-2 mm/year) compared to 316L stainless steel which registered a corrosion rate of 5.14 × 10^-4 mm/year.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.775-778
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• 2012

The potential energy surfaces of ammonia molecule adsorptions on the symmetrically chlorinated Si(100)-$2{\times}1$ surface were explored with SIMOMM:MP2/6-31G(d). It was found that the initial nucleophilic attack by ammonia nitrogen to the surface Si forms a $S_N2$ type transition state, which eventually leads to an HCl molecular desorption. The second ammonia molecule adsorption requires much less reaction barrier, which can be rationalized by the surface cooperative effect. In general, it was shown that the surface Si-Cl bonds can be easily subjected to the substitution reactions by ammonia molecules yielding symmetric surface Si-$NH_2$ bonds, which can be a good initial template for subsequent surface chemical modifications. The ammonia adsorptions are in general more facile than the corresponding water adsorption, since ammonia is better nucleophile.

• The Korean Journal of Ceramics
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• v.1 no.3
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• pp.160-164
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• 1995

Mechanical and chemical tests were performed on $Zro_2 \cdot SiO_2$ glass fibers manufactured by the sol-gel method and E-glass fibers-reinforced cement composites in order to investigate the interactions between glass fibers and cement matrices. Chemical attack leads to corrosion of the glass fiber surfaces. In the corrosion reactions, the surface of $30ZrO_2 \cdot 70 SiO_2$ glass fibers developed a densified concentric layer, which consists of glass corrosion products with much higher Zr and lower Si than the fresh glass fiber. The layer of reaction product is regarded to stiffen the cement matrices and provide a useful improvement to the mechanical properties. The addition of $ZrO_2$ content increases the corrosion resistance of glass fibers in cement by forming a passivating layer on the surface of glass fibers.

• Journal of the Society of Disaster Information
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• v.6 no.2
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• pp.21-44
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• 2010

Today, in response to chemical, biological and radiological terrorism has been active for the study. However, if chemical, biological and radiological attack has occurred to respond to the agency has not conducted the research. The purpose of this study are as follows. First, South Korea and the United States 'CBR terrorism' comparative analysis of the response system. Second, South Korea 'CBR terrorism' measures to improve the system response is presented. To achieve the purpose of this study, the following research is carried out. First, determine the status of the case of CBR incident. Second, the United States 'CBR terrorism' response systems and organizational approaches. Third, Korea's 'CBR terrorism' response system and the problem is derived.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2294-2298
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• 2009

In present work an attempt was made to synthesize various analogues of levofloxacin by introducing new functionality at carboxylic group position via nucleophilic substitution reaction. For this purpose the carboxylic group at C-6 was esterified and later subjected to nucleophilic attack at the carbonyl carbon by various aromatic amines. Structure of the analogues was confirmed by different techniques i.e. IR, $^1H$ NMR and mass spectrometry. The antibacterial activity of the derivatives was also assessed and compared with the parent against a series of Gram-positive and Gramnegative bacteria. A synergistic as well as antagonistic behavior was observed in these derivatives. Additionally unlike levofloxacin, the derivatives were also found to modulate oxidative burst response of phagocytes exhibiting moderate to significant inhibitory activity.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.58-58
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• 2000

Recently low resistance of bus line is required for large screen size RFT-CLD panels. As a result, lower resistance Al-alloy is currently reviewed extensively. The resistivity is required smaller than 10$\mu$$\Omega$cm and high resistance of chemical attack is required. In this paper, Al-W thin film were deposited on glass substrates by D.C magnetron sputtering system under various condition for high chemical resistance. Its properties were characterized by SEM, AFM, XRD, 4-point-probe, and cyclic voltammertry. The optimal condition of Al-W was 10$0^{\circ}C$, 100W, 0.4Pa, 23sccm(Ar) and 35$0^{\circ}C$, 20min. annealing. At that condition the resistivity of Al-W(3 wt.%) was about 11$\mu$$\Omega$cm. And when wt.% of W in Al-W alloy was higher than about 4%, Al-W alloy thin film has high chemical resistance.

• Bulletin of the Korean Chemical Society
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• v.11 no.1
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• pp.60-64
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• 1990

The reactions of alkanesulfonyl chlorides with pyridines in the presence of various solvents have been studied by means of kinetic method. Alkanesulfonyl chlorides bearing ${\alpha}$-hydrogen with the normal attack of pyridine is found to be at the ${\alpha}$-hydrogen with elimination to form the sulfene intermediate evidently. From the mass spectra by the reaction of ethanesulfonyl chloride with 3-picoline in the presence of methanol-$d_1$, it has shown that the reaction has a witness favorable to the slulfene intermediate.

• Bulletin of the Korean Chemical Society
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• v.5 no.1
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• pp.32-37
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• 1984

The photoreaction of 2, 3-benzo-1, 1-diphenyl (or dimethyl)-1-sila-2-cyclobutene (9 or 10) with an aldehyde or ketone results in 1:1 cycloadduct of [4 + 2] type. In the reactions of 2, 3-benzo-1, 1-dimethyl-1-sila-2-cyclobutene (10) with acetone and butanone, another 1:1 adducts (13) were also formed, respectively. The following facts indicate that the formation of adduct involves an attack of a triplet carbonyl compound on the silicon of the benzosilacyclobutene, an $S_H2$ process. (1) Even when the reaction of 9 with acetophenone was carried out under conditions such that more than 99% of incident light was absorbed only by acetophenone using the filter solution of aq. cupric sulfate, the same adduct was still formed. (2) When the reaction of 9 with acetone was carried out under oxygen atmosphere, only trace amount of adduct was formed.

• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.453-455
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• 1994

Semiempirical MO calculations are applied to estimate the substituent effects on acylations of the nonfused N-vinyl-2-amino $\beta-lactams$ having frameworks analogous to 3-cephems. The stabilization energy for the reaction intermediate of the nucleophilic attack by the hydroxide ion is selected as the reactivity index and calculated by AM1 and PM3 methods for the model $\beta-lactams$ with substituents at the C1 and N-vinyl terminal positions. The reactivities are larger for -SH connected to the C1 and strong $\pi-acceptors$ at the N-vinyl terminal implying the large reactivity for known active cephalosporins. Quantum chemical calculation of stabilization energy could be useful in correlating antibiotic activities of many compounds obtained as derivatives of a lead compound.