• Bulletin of the Korean Chemical Society
• /
• v.25 no.12
• /
• pp.1877-1880
• /
• 2004

The simple and convenient determination of trace Hg(II) with its 2-mercaptobenzothiazole (MBT) complex in cetyltrimethylammonium bromide (CTAB) media has been studied. The UV-visible spectrum of Hg(II)-MBT complex in CTAB media had a good sensitivity and reproducibility. The Hg(II)-MBT complex in CTAB solution was very stable at pH 10.0 and could be quantitatively complexed if MBT were added to the sample solution more than 10 equivalent of Hg(II). The optimum concentration of CTAB was 0.001%. The calibration curve of Hg(II)-MBT complex with good linearity ($R^2$ = 0.9985) was obtained at the concentration range between $1.0{\times}10^-7$ and $1.0{\times}10^-5$ M in 0.001% CTAB media. The detection limit was $3.1{\times}10^-8$ M (6.2 ng m$L^{-1}$). Hg(II) in the synthetic samples and in the wastewater of the university's wastewater tank and the industrial wastewater tank could also be determined. Based on the experimental results, this proposed technique could be applied to the simple and convenient determination of trace Hg(II) in real samples.

• Mycobiology
• /
• v.46 no.1
• /
• pp.47-51
• /
• 2018

In the present study, the characterization and properties of silver nanoparticles from Yucca shilerifera leaf extract (AgNPs) were investigated using UV-visible spectroscopic techniques, zeta potential, and dynamic light scattering. The UV-visible spectroscopic analysis showed the absorbance peaked at 460 nm, which indicated the synthesis of silver nanoparticles. The experimental results showed silver nanoparticles had Z-average diameter of 729 nm with lower stability (195.1 mV). Additionally, our dates revealed that AgNPs showed broad spectrum antagonism ($p{\leq}.05$) against Fusarium solani (83.05%) and Macrophomina phaseolina (67.05%) when compared to the control after nine days of incubation. Finally, AgNPs from leaf extracts of Y. shilerifera may be used as an agent of biocontrol of microorganism of importance. However, further studies will be needed to fully understand the agronanotechnological potentialities of AgNPs from Yucca schidigera.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.7
• /
• pp.528-533
• /
• 2013

We focused on the development of red azo colorants with high thermal stability and good solubility for LCD color filter in this research. For the synthesis of hybrid azo colorants, we used the couplers of aniline, naphthol and benzoimidazol functional group. The synthesized hybrid azo colorants were charaterized by using NMR, UV/visible spectroscopy, FT-IR, EA and TGA. They represented the maximum absorption wavelengths which are longer than 500 nm in UV/visible spectrum. So they were confirmed to be suitable for red colorants of LCD color filter. Azo compound (1a, 1b) with aniline functional group had good solubility in organic solvents such as acetone, methanol, chloroform and PGMEA. Moreover azo compounds (1c, 1d and 1e) with naphthol and benzoimidazolone functional group gave excellent thermal stability higher than $250^{\circ}C$ in TGA thermograms.

• Korean Journal of Materials Research
• /
• v.25 no.3
• /
• pp.144-148
• /
• 2015

Cubic mesocrystal $CeO_2$ was synthesized via a hydrothermal method with glutamic acid ($C_5H_9NO_4$) as a template. The XRD pattern of a calcined sample shows the face-centered cubic fluorite structure of ceria. Transmission electron microscopy (TEM) and the selected-area electron diffraction (SAED) pattern revealed that the submicron cubic mesocrystals were composed of many small crystals attached to each other with the same orientation. The UV-visible adsorption spectrum exhibited the red-shift phenomenon of mesocrystal $CeO_2$ compared to commercial $CeO_2$ particles; thus, the prepared materials show tremendous potential to degrade organic dyes under visible light illumination. With a concentration of a rhodamine B solution of 20 mg/L and a catalyst amount of 0.1 g/L, the reaction showed higher photocatalytic performance following irradiation with a xenon lamp (${\geq}380nm$). The decoloring rate can exceed 100% after 300 min.

• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.1197-1199
• /
• 1993

The molecular electronic devices of organic materials are of current interest. Langmuir-Blodgett(LB) method is the most possible candidate for the development of the molecular electronic devices. One of the critical problems for applications of the LB films to the commercial products will be an electrical conductivity within a LB film. We studied the monolayer characteristics and electrical conductivity of the 1:1 mixture LB films of N-docosylquinolium-TCNQ and $TCNQ^0$. There were some differences in the $\pi-A$ isotherm and UV-visible absorption spectrum of N-docosylquinolium-TCNQ and 1:1 mixture. The small critical area of the $\pi-A$ isotherm for 1:1 mixture may result from the bilayer formation. We confirmed the incorporation of the $TCNQ^0$ with the N-docosylquinolium-TCNQ from the UV-visible absorption spectrum. But the electrical conductivity measured was $10^{-7}$ S/cm for the 1:1 mixture film layered at the surface pressure of 35 mN/m. We couldn't gain any electrical conductivity by mixing the $TCNQ^0$ into the N-docosylquinolium-TCNQ layer. We supposed that $TCNQ^0$ mixed in was not packed parallel to the TCNQ anion radical faces.

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

• Korean Journal of Human Ecology
• /
• v.10 no.3
• /
• pp.263-274
• /
• 2001

This study investigated the dyeability on silk, wool and rotten fabrics dyed with Magnolia liliflora leafs. In addition, the fastness of washing, perspiration, rubbing, drycleaning and the effects of its pigment on bacterial reduction and uv-B protection were also investigated. The results were as follows : It was found that uv-visible absorption spectrum showed two strong absorption peaks in the range of $250{\sim}340nm$. The optimum dyeing condition of the pigments extracted from the Magnolia liliflora leafs was dyeing with 0.5% mordants and three repeated dyeing at $95^{\circ}C$ for 1hr. When the wool fabric was dyed with Magnolia liliflora leaf, dyeing properties was the best among the three fabrics. Washing fastness of dyed fabrics was very low, drycleaning fastness was good and the other fastness were good. Light fastness of three fabrics dyed by Magnolia liliflora leafs increased by mordant treatment, especially copper sulfate treatment. The bacterial reduction and uv-B protection of dyed wool fabric with Magnolia liliflora leafs also increased.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.11 no.3 s.25
• /
• pp.25-32
• /
• 1987

The purpose of this study is to investigate optical behaviour of coloring matter of gromwell -extracted by water, acetic acid/methanol, and the other solvents. The results were as following: UV, VIS spectra of the solution of coloring matter of gromwell extracted by water at below $80^{\circ}C$ did not reveal in the range of the visible light wavelength and coloring matter of gromwell decomposed to blue particle at $95^{\circ}C$. The solution extracted by acetic acid/methanol was tinged with reddish purple and its spectra shifted to the longer wavelength according to increase of the solvent temperature. The color of the solution extracted by water became extinct as time went by, but that extracted by acetic acid/methanol kept up original color. In case of dried gromwell, extraction by acetic acid/methanol was easier than by water, and variation of spectra did not appear but showed hypochromic shift.

• Conservation Science in Museum
• /
• v.12
• /
• pp.9-17
• /
• 2011

This study examined non-destructive UV-Vis spectrophotometry as well as 3-D fluorescence spectrophotometry of textile that made use of red dye such as Sappan wood, madder, Safflower, Gromwell. The authors produced two textile specimen that were dyed by not only two kinds of textile (cotton and silk) but also three kinds of mordanting (no-mordanting, alumen and iron), and they investigated effects of each dye material upon investigation results. At analysis with UV-Vis spectrophotometry of dyed textile specimen, dyeing made by sappan wood, madder and gromwell had significant difference depending upon mardant regardless of kinds of textile, and safflower had no significant difference depending upon textile and mordant. At analysis with 3D-fluorescence spectrophotometry, specimen dyed with sappan wood had difference with mordants, and with madder, there were difference with textiles, and safflower had inherent fluorescence spectrum regardless of textiles and mordants, while gromwell had no fluorescence spectrum.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.16 no.3
• /
• pp.43-60
• /
• 1998

The photosensitive properties and spectroscopic characteristics in the organic photoconductor(OPC) with carrier generation layer(CGL) of poly(vinylbutyral)(PVB) and polycarbonate(PC) doped with titanyl phthalocyanine(TiOPc) were investigated. The change of crystal structure of TiOPc dispersed with PVB and PC was shown by UV-visible reflective spectrum and FT-IR spectrum and mainly caused by the difference of solubility of solvent and the interaction between TiOPc and binder. The particle size of TiOPc dispersed with PVB measured by SEM was smaller than in PC. The crystal structure of TiOPc dispersed with PVB was amorphous type and in PC was $\alpha$type. It was found that the photosensitive properties of OPC were dependent on the change of absorbance and ionization potential of TiOPc occurred from the difference of crystal structure. In this work, the photosensitivity of OPC of TiOPc dispersed with PVB was better than PC due to the crystal type and the smaller particle size.