• International journal of advanced smart convergence
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• v.8 no.3
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• pp.27-38
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• 2019

I reviewed about dyeing fastness and functional properties of the non-mordant dyed cotton and iron mordant dyed cotton with astringent persimmon juice. In the UV-VIS spectrum of astringent persimmon juice, the maximum absorption wavelength of the juice was 272.0 nm, which was a characteristic peak of tannin. In dyeing fastness, light fastness of the non-mordant dyed cotton was a little low at grade 2~3. But by the iron mordant treatment, the light fastness was good at grade 4. Dry cleaning fastness to discoloration and contamination was excellent at grade 4~5 for both the non-mordant dyed cotton and iron-mordant dyed cotton. Their rub fastness were grade 3 and grade 2~3 respectively, in the dry condition, and grade 2~3 and grade 3 respectively, in the wet condition. In the perspiration fastness of the non-mordant dyed cotton, the discoloration from acidity and alkalinity was grade 3~4 and grade 3, respectively, and contamination from acidity and alkalinity was relatively good at grade 4. Meanwhile, in the perspiration fastness of the non-mordant dyed cotton, discoloration from acidity and alkalinity was fair, both recording grade 3~4, and contamination from acidity and alkalinity was very good, both recording grade 4~5. In the ultraviolet protection effect of the non-mordant dyed cotton and iron-mordant dyed cotton, the ultraviolet protection factor was both 50+, both of which showed an excellent ultraviolet blocking effect. And the protection rate of UV-A appeared 98.4% and 99.1%, respectively, and the protection rate of UV-B showed 98.7% and 99.2, respectively. In addition, both exhibited an excellent deodorization rate over 99.9% or more, irrespective of the passage of time. Also, both showed an excellent antimicrobial activity over 99.9% or more against Staphylococcus aureus and Klebsiella pneumoniae.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.207-207
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• 2008

ZnO is one of the widely utilized n-type semiconducting oxide materials in the field of optoelectronic devices. For its application to the fabrication of promising ultraviolet (UV) photodetectors, ZnO with various structures has been extensively studied. However, study on the photodetectors using zero-dimensional (0-D) ZnO nanoparticle is scarce while the 0-D nanoparticle structure has many advantages compared to the other dimensional structures for absorption of light. In this study, the photocurrent characteristics of ZnO nanoparticles were investigated through a simply pasting of the nanoparticles across the pre-patterned electrodes. Then the photoluminescence (PL) characteristic, photocurrent response spectrum, photo- and dark-current and photoresponse spectrum were investigated with a He-Cd laser and an Xe lamp. An dominant PL peak of the ZnO nanoparticles was located at the wavelength of 380 nm under the illumination of 325-nm wavelength light. The ratio of photocurrent to dark current (on/off ratio) is as high as 106 which is considerable value for promising photodetectors. On the other hand, the time constants in photoresponse were relatively slow. The reasons of the high on/off ratio and relatively slow photoresponse characteristic will be discussed.

• 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.

• Advances in nano research
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• v.13 no.4
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• pp.325-339
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• 2022

Endophytes ascertain a symbiotic relationship with plants as promoters of growth, defense mechanism etc. This study is a first report to screen the endophytic population in Waltheria indica, a tropical medicinal plant. 5 bacterial and 3 fungal strains in leaves, 3 bacterial and 1 yeast species in stems were differentiated morphologically and identified by biochemical and molecular methods. The phylogenetic tree of the isolated endophytes was constructed using MEGA X. Silver nanoparticles were biosynthesized from a rare endophytic bacterium Cupriavidus metallidurans isolated from the leaf of W. indica. The formation of silver nanoparticles was confirmed by UV-Visible spectrophotometer that evidenced a strong absorption band at 408.5 nm of UV-Visible range with crystalline nature and average particle size of 16.4 nm by Particle size analyzer. The Fourier Transform Infra-Red spectrum displayed the presence of various functional groups that stabilized the nanoparticles. X-ray diffraction peaks were conferred to face centered cubic structure. Transmission Electron Microscope and Scanning Electron Microscope revealed the spherical-shaped, polycrystalline nature with the presence of elemental silver analyzed by Energy Dispersive of X-Ray spectrum. Selected area electron diffraction also confirmed the orientation of AgNPs at 111, 200, 220, 311 planes similar to X-ray diffraction analysis. The synthesized nanoparticles are evaluated for antimicrobial activity against 7 bacterial and 3 fungal pathogens. A good zone of inhibition was observed against pathogenic bacteria than fungal pathogens. Thus the study could hold a key aspect in drug discovery research and other pharmacological conducts of human clinical conditions.

• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.864-872
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• 1994

Absorption spectra of thermochromic spiropyran and spirooxazine derivatives were investigated. The effects of solvent polarity on the absorption spectra indicate that the merocyanine-like form of non-substituted spiro compound is likely to the quinoid type. However, the merocyanine-like form of electron-withdrawing substituted spiro compound is likely to the zwitter-ion type. The enthalpy changes between the closed and merocyanine-like forms were measured. The enthalpy change of spiro compound decreases as the solvent polarity increases. The UV-Vis spectrum of merocyanine-like form was resolved into three Lorentzian-Gaussian product bands. The solvent dependence of the amount of the three band was also examined.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1659-1663
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• 2012

New semiconducting polymer, poly[1,4-bis(($E$)-2-(5-bromo-3-dodecylthiophen-2-yl)vinyl)benzene], was designed, synthesized and characterized. The structure of polymer was confirmed by $^1H$-NMR, IR and elemental analysis. The polymer was soluble in specific organic solvent. The weight-average molecular weights (MW) of polymer was found to be 11,000 with polydispersity of 1.82. UV-Visible absorption spectrum showed the maximum absorption at 428 nm (in solution) and 438 nm (in film). The highest occupied molecular orbital (HOMO) energy of the polymer is -5.36 eV by measuring cyclic voltammetry (CV). A solutionprocessed polymer thin film transistor device shows a mobility of $8.59{\pm}10^{-4}\;cm^2\;V^{-1}\;s^{-1}$, an on/off current ratio of $2.0{\times}10^4$.

• Textile Coloration and Finishing
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• v.9 no.1
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• pp.44-49
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• 1997

Recent investigation and developments of A. Iqbal on diketo-pyrrolo-pyrrole (DPP) pigments has prompted us to synthesize and close observation of a few properties of these molecules. Described are synthesis, via 1-phenyl-2-ethoxycarbonyl-5-pyrrolinone intermediate, of asymmetric derivatives such as 1,4-Diketo-3-(4-chlorophenyl)-6-phenyl-pyrrolo-(3,4c)-pyrrole (4), 1,4-Diketo-3-(4-bromophenyl)-6-phenybpyrrolo-(3,4c)-pyrrole (5), 1,4-Diketo-3-(3-cyanophenyl)-6-phenyl-pyrrolo-(3,4c)-pyrrole (6), 1,4-Diketo-3-(4-cyanophenyl)-6-phenyl-pyrrolo-(3,4c)-pyrrole (7), 1,4-Diketo-3-(4-pyridyl)-6-phenyt-pyrrolo-(3,4c)-pyrrole (8), 1,4-Diketo-3-(3-pyridyl)-6-phenyl-pyrrolo-(3,4c)-pyrrole (9), 1,4-Diketo-3-(2-pyridyl)-6-phenyl-pyrrolo-(3,4c)-pyrrole (10), 1,4-Diketo-3-($\beta$-naphthyl)-6-phenyl-pyrrolo-(3,4c)-pyrrole (11), and UV-Vis absorption spectrum of the above compounds. Results from calculation of their absorption maxima using PISYSTEM are also described.

• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.812-815
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• 2005

Effects of poly-${\gamma}$-glutamate (PGA) on antioxidative characteristics of amino-carbonyl reaction products of glucose were investigated. Rapid browning reaction was observed under heat and alkaline condition (pH 8.2). Browning products were separated by Sephadex G-50, and brown color intensity and electron-donating ability of DPPH (2,2-diphenyl-1-picrylhydrazyl) of each fraction were measured. Fraction-7 (F-7) and -20 (F-20) showed high DPPH scavenging values. UV-VIS absorption spectrum of F-20 was similar to melanoidin peak, and F-7 showed maximum absorption peak at 270 nm. Molecular weight of F-7 was over 35 kDa as determined by SDS-PAGE. Although F-20 could not be measured on SDS-PAGE, its size was smaller than F-7.

• Journal of the Korean Applied Science and Technology
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• v.13 no.1
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• pp.75-85
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• 1996

The absorption spectra of synthesis of long chain fatty acid containing azobenzene start from p-(p'-hydroxy phenyl azo)-benzoic acid was investigated by ultraviolet spectrophotometery in chloroform solvent at the various temperature. In addition, The pressure-area of the water-air interface was obtained and the LB film was fabricated onto a quartz slide and quartz crystal by conventional Langmuir-Blodgett(LB) method. The UV absorption spectra of Langmuir-Blodgett(LB) film on quartz slide and spectrum of monolayer formed on quartz crystal have been measured. Long chain fatty acid containing azobenzene are induced phtoisomerization by the application of u. v. and visible light irradiation alternatively the reversibility of phtoisomerization was more clear difference when the number of $C_{n}$ increased but, not so good at $C_{14}-azo$. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of $C_{n}$ increased. A surface pressure of 20mN/m was obtained as a proper one for a film deposition. The photoisomerization at LB films were induced by application of UV and visible light irradiation alternatively. So the LB film of long chain fatty acid containing azobenzene has possibility to being applied to functional molecular devices such as photomemory and light switching.

• Journal of the Korean Chemical Society
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• v.39 no.5
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• pp.350-355
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• 1995

UV spectrophotometric investigation has been carried out on the system of charge-transfer (CT) complex with iodine and tetramethyltin in carbon tetrachloride solvent. The transient CT absorption spectrum can be observed in ${\lambda}_{max}=270nm$ and the subsequent disappearance of CT absorption spectrum was accompained by the cleavage of tetramethyltin with iodine (iododestannylation). From there, the rate constants for the iododestannylation were determined at 10, 20 and $35^{\circ}C$ up to 1200 bar and the reaction rates were increased with increasing temperature and pressure. From these rate constants, the values of the activation parameters (${\Delta}V^{\neq},\;{\Delta}{\beta}^{\neq},\;{\Delta}H^{\neq}\;and\;{\Delta}S^{\neq}$) were obtained and from these values discussed in terms of solvent structure variation of transition state and mechanism. From these results, it was found that the reaction is followed with $S_F2$ mechanism and weakened $S_F2$ mechanism nature by increasing pressure.