• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.209-211
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• 2004

In the Langmuir-Boldgett(LB) technique, a monolayer on the water surface is transferred on to a substrate, which is raised and dipped through the surface, and one can obtain multilayers in which constituent molecules periodically are arranged in layer. The LB technique has attracted considerable interest in the fabrication of electrical and electronic device, e.g.. Many researchers have investigated the electrical properties of monolayer and multiplayer films. Dendrimers represent a new class of synthetic macromolecules sharacterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends, which distinguishes dendrimers from conventional starlike polymers and microgels. Azobenzene dendrimer is one of the dendritic macromolecules that includes the azo-group which exhibits a photochromic character. Due to the presence of the charge transfer part, the azo-group, and having a rod-shaped structure, these compounds are expected to have the potential interest in electronics and ptoelectronics, especially in nonlinear optics. In the present paper, we give a pressure stimulation into organic thin films and detect the induced displacement current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.358-359
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• 2006

In the Langmuir-Blodgett (LB) technique, a monolayer on the water surface is transferred onto a substrate, which is raised and dipped through the surface. From this, multilayers can be obtained in which constituent molecules are periodically arranged. The LB technique has attracted considerable interest in the fabrication of electrical and electronic devices. Many researchers have investigated the electrical properties of monolayer and multiplayer films. Dendrimers represent a new class of synthetic macromolecules characterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends that distinguish dendrimers from conventional star-like polymers and microgels. The azobenzene dendrimer is one of the dendritic macromolecules that include the azo-group exhibiting a photochromic character. Due to the presence of the charge transfer element of the azo-group and its rod-shaped structure, these compounds are expected to have potential interest in electronics and ptoelectronics, especially in nonlinear optics. In the present paper, we give pressure stimulation to organic thin films and detect the induced displacement current.

• Journal of the Optical Society of Korea
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• v.19 no.5
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• pp.508-513
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• 2015

A capacitive-type touch screen panel (TSP) composed of silver nanowire (AgNW) crossing electrodes and transparent bridge structures was fabricated on a polycarbonate film. The transparent bridge structure was formed with a stack of Al-doped ZnO (AZO) electrodes and SU-8 insulator. The stable and robust continuity of the bridge electrode over the bridge insulator was achieved by making the side-wall slope of the bridge insulator low and depositing the conformal AZO film with atomic layer deposition. With an extended exposure time of photolithography, the lower part of the SU-8 layer around the region uncovered by the photomask can be exposed enough to the UV light scattered from the substrate. This leads to the low side-wall slope of the bridge insulator. The fabricated TSP sample showed a large capacitance change of 22.71% between with and without touching. Our work supplies the technological clue for ensuring long-term reliability to the highly flexible and transparent TSP made by using conventional fabrication processes.

• Journal of Preventive Medicine and Public Health
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• v.35 no.3
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• pp.229-235
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• 2002

Objectives : To evaluate the effects on the formation of benzidine-hemoglobin, and benzidine metabolite-hemoglobin adducts, caused by pretreatment with the known xenobiotic metabolism effectors, ethanol and phenobarbital, in rats administered Direct Black 38 dye. Methods : The experimental rats were divided into three groups: a control group, an ethanol group and a phenobarbital group. Rats were pretreated with ethanol (1g/kg) or phenobarbital (80mg/kg) 24 hours prior to the oral administration of Direct Black 38 (0.5mmol/kg), with the control group being administered the same amount of distilled water. Blood samples were obtained from the vena cava of 5 rats from each group prior to, and at 30 min, 3h, 5h, 9h, 12h, 24h, 48h, 72h, 96h, and 144h following the oral administration of Direct Black 38. Directly after sampling the blood was separated into hemoglobin and plasma, with the adducts being converted into aromatic amines by basic hydrolysis. Hydrolyzed benzidiene, monoacetylbenzidine and 4-aminobiphenyl were analyzed by reverse-phase liquid chromatography with an electrochemical detector, The quantitative amount of the metabolites was expressed by the hemoglobin binding index (HBI). Results : In the ethanol group, benzidine-, monoacetylbenzidine-, and 4-aminobiphenyl-HBI were increased to a greater extent than those in the control group. These results were attributed to the ethanol inducing N-hydrgxylation, which is related to the formation of the hemoglobin adduct, In the phenobarbital group, all the HBIs, with the exception of the benzidine-HBI, were increased to a greater extent than those of the control group. These results were attributed to the phenobarbital inducing N-hydroxylation related to the formation of the hemoglobin adduct. The N-acetylation ratio was only increased with the phenobarbital pretreatment due to the lower benzidine-HBI of the phenobarbital group compared to these of the control and ethanol groups. The N-acetylation ratios for all groups were higher than f for the duration of the experimental period. Although the azo reduction was unaffected by the ethanol, it was inhibited by the phenobarbital, The ratio of the benzidine-HBI in the phenobarbital group was lower than those of the ethanol the control groups for the entire experiment. Conclusion : Our results indicate that both ethanol and phenobarbital increase the formation of adducts by the induction of N-hydroxylation, but also induced N-acetylation. Phenobarbital decreased the formation of benzidine-HBI due to the decrease of the azo reduction. These results suggest that the effects or ethanol and phenobarbital need to be considered in the biochemical monitoring of Direct Black 38.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.977-983
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• 2002

This study was performed to establish the precise and rapid method to distinguish croakers through the pigment analysis of colored imported white croakers for adultration. We surveyed the coloring behaviors, extraction test by water and organic solvent and using pigments such as targeting, curcumine, and azo dye products. The pigment of yellow croaker is not stained on wet cloth or tissue which is rubbed on epidermis of yellow croaker and was not eluted in water extraction test, while adulterated pigments were easily extracted by water and acetone, but edible diluted yellow, Yellow No. 4 and Yellow No. 5 were not extracted. Reactive pigment was detected easily by extraction with water and dispersed pigment was also detected by extraction test. As a result of discoloring characteristics of carotene having similar structure to yellow croaker and azo dye by oxidation and reduction, azo dyes were not discolored by oxidation with sodium percarbonate or peracetic acid but that were discolored by oxidation with Fenton reagent after 1hr and by hypochlorite promptly. On the other hand, carotenes were not discolored by sodium precarbonate and Fenton reagent but discolored by sodium hypochlorite after 2 hr and by peracetic acid promptly. Azo dyes were discolored by reduction with sodium hydrosulfite and sodium carbonate but carotenes were not discolored by these reagents. This discoloring test was applicable to detect adulterated pigments and other marine product.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.28-31
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• 1998

Photoresponsive polymers are being intensely investigated over last two decades, which can be attributed to both fundamental and applied significance. Presently the attention is being directed to these materials in view of their possible application in nonlinear optics and optoelectronics. It was demnstrated quite early that by covalent fixation of both photochromic group and the mesogenic group to the same polymer main chain high concentration of photochromic group can be attained.(omitted)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.904-907
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• 2003

We synthesized dendrimers containing light switchable units, azobenzene group. To apply to the molecular level devices or data storage system using Langmuir-Blodgett(LB) film, we firstly investigated the monolayer behavior using the surface pressure-area(${\pi}-A$) isotherms at air-water interface. And then the surface pressure shift of monolayer by light irradiation was also measured to the dendrimer with azobezene group. As a result, the monolayer of dendrimer with azobenzene group showed the reversible photo-switching behavior by the isomerization of azobenzene group in their periphery. This results suggest that the dendrimers with azobenzene group can be applied to high efficient nano-device of molecular level. And we measured the electrical properties by MIM and STM. The dendrimer with azobenzene group compared trans form and cis form at electrical properties.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.169-169
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• 2006

Novel liquid crystalline malonic ester monomers were synthesized from malonyl dichloride and mesogenic alcohols as a photoresponsive group. The monomers were polymerized with aliphatic or aromatic dibromides in the presence of sodium hydride to give 8 kinds of novel poly(malonic esters) with two symmetrical azobenzene groups. We found that the resulting polymer films could be used as rewritable optical data storage (or holographic image) media through a photoisomerization of azobenzene group by Ar laser irradiation. The sensitivity of data recording was dependent not only on the thickness of the polymeric thin film but also on the intensity of laser beam.

• Textile Coloration and Finishing
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• v.13 no.5
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• pp.24-24
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• 2001

Kinetics and mechanism for alkaline hydrolysis of C. I. Disperse Blue 79(B-79) which is 4-N, N-diacetoxyethyl-2-acylamino-5-ethoxy -2′-bromo-4′,6′-dinitroazobenzene were investigated. The color strength of B-79 in acetone/water solutions of various NaOH concentrations decreased continuously. The hydrolysis rate of B-79 increased with increasing alkali concentration and appeared following first order reaction. The observed rate constants for various concentrations of B-79 showed similar values, and B-79 was hydrolyzed by first order reaction for dye concentration. Therefore, it was confirmed that the overall reaction follow second order kinetics and proceed via S/sub n/2 reaction. From the study on kinetics and spectrometric analysis, it was proposed that the rate determining step of the hydrolysis reaction of B-79 is the nucleophilic substitution reaction - that is the reaction of the rapid attack of $OH^{-}$ on the carbon atom, which is in acceptor ring, adjacent to azo group to break the C-N bond. And it was also found that the final hydrolysis products of B-79 include both the acceptor ring in the form of sodium salt and the donor ring possessing 4-N,N-dihydroxyethyl group converted from 4-N,N-diacetoxyethyl group.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.7
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• pp.627-633
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• 2002

Many isolated featureless domains were explicitly observed even at the air-water interface. We measured the surface pressure shift originating from the photo-isomerization of azobenzene units on the periphery of dendrimers. The maximum surface pressure was gradual1y increased and saturated by cyclic compression and decompression. By irradiation of 365 [nm] light, the surface pressure was increased, which was originated by the photo-isomerization process of the azobenzene group on the periphery from trans to cia form. The increase of the dipole moment ($\mu$), which may increase the interaction among Azo dendrimer molecules, made an important role on surface pressure shift. From the absorbance spectrum by UV irradiation and heat treatment, we can see that the absorbance in the UV region decreases with the increase of the UV irradiation time, but the peak at 350 m, characteristic of dendrimers in the LB monolayers, was not shifted until four irradiation cycles. This suggests that optical behavior and morphological change are affected by the functional group and the symmetric chain.