• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.4
• /
• pp.483-489
• /
• 2007

We have investigated quantitative measurement techniques of the degree of dispersion of single-walled carbon nanotubes (SWNTs). SWNTs were suspended in aqueous media using a sodium dodecyl sulfate (SDS) surfactant. SWNTs with different dispersion states were prepared by controlling the intensity and time of sonication and centrifugation. The laser spectroscopic techniques were employed to characterize the dispersion state; i.e., raman fluorescence and absorption spectroscopic techniques. Raman spectroscopy has been used to probe the dispersion and aggregation state of SWNTs in solution. Individually suspended SWNTs show increased fluorescence peaks and decreased roping peaks at a raman shift 267 $cm^{-1}$ compared with the samples containing bundles of SWNTs. The ultraviolet-visible-near infrared (UV-vis-NIR) absorption spectrum of decanted supernatant samples show sharp van Hove singularity peaks

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.4 no.1
• /
• pp.1-7
• /
• 2006

The spectroscopic characteristics of Pu (III, IV, V, VI) in the HCl media were investigated by measuring Pu oxidation states using a UV-Vis-NIR spectrophotometer (400-1200 nm) after adjusting Pu oxidation states with oxidation/reduction reagents. Pu in stock solution was reduced to Pu(III) with $NH_2OH$ HCl, and oxidized to Pu(IV) and Pu(VI) with $NaNO_2$ and $HClO_4$, respectively. Also, Pu(V) was adjusted in the Pu(VI) solution with $NH_2OH$ HCl. The major absorption peaks of Pu (IV) and Pu(III) were measured in the 470 m and 600 nm, respectively. The major absorption peaks of Pu (VI) and Pu(V) were measured in the 830 nm and 1135 nm, respectively. There was not found to be significant changes of UV-Vis absorption spectra for Pu(III), Pu(IV) and Pu(VI) with aging time, except that an unstable Pu(V) immediately reduced to Pu(III).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.5
• /
• pp.314-319
• /
• 2015

In this research, we focused on the development of cy3 dye with high thermal stability and good solubility for LCD color filter. Cy3 dyes were prepared through the synthetic procedure of two steps. The synthesized cy3 dyes were characterized by using NMR, FT-IR, UV/Vis spectroscopy, and TGA. These cy3 dyes showed maximum absorption wave length (${\lambda}_{max}$) in the range of 549~555 nm in UV/Vis spectrum. And we confirmed that solubility characteristics and thermal stability of cy3 dyes were dependent on the structure of counter cation. Cy3 dyes with methyl counter cation and ethyl counter cation have good solubility in organic solvents such as chloroform, ethanol, and PGME. Moreover, Cy3 dye with ethyl counter cation gave excellent thermal stability in TGA thermograms. And Cy3 dye with ethyl counter cation showed good result in photoresist film test.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.10
• /
• pp.2269-2279
• /
• 2009

Six metal-free organic dyes having thiophene (1), benzene-thiophene (2), thiophene-benzene (3), thiophene-pyridine (4), thiophene-thiophene (5), and pyridine (6) linkers between 9,9-dimethylfluorenyl terminal group and $\alpha$-cyanoacrylic acid anchor were synthesized. Among them, organic dye 5 showed the longest ${\lambda}_{max}$ value (424 nm) in UV-Vis absorption spectrum, better incident monochromatic photon-to-current conversion efficiency (IPCE), highest short circuit photocurrent density ($J_{SC},\;9.33\;mA^2/cm^2$), and highest overall conversion efficiency ($\eta$, 3.91%).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.1
• /
• pp.35-39
• /
• 2016

In this research, we focused on the improvement of cy3 dye's characteristics for LCD color filter. Solubility and thermal stability are main characteristics of dyes for LCD color filter. We performed experiment to change counter cation of cy3 dyes with alkoxy substituent for these purposes. These cy3 dyes (1b~5b) were prepared through the synthetic procedure of three steps. The synthesized new cy3 dyes were charaterized by using NMR, FT-IR, UV/Vis spectroscopy, and TGA. These cy3 dyes showed purple color and maximum absorption wavelength (${\lambda}_{max}$) in the range of 578~590 nm in UV/Vis spectrum. We confirmed that solubility and thermal stability of cy3 dyes were dependent on the structure of counter cation. Cy3 dyes with alkoxy substituent have good solubility in organic solvents such as dichloromethane, methanol, and acetone. Especially, Cy3 dye with 4-nitrobenzyl counter cation (5b) gave excellent solubility characteristics.

• 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.

• 한국생물공학회:학술대회논문집
• /
• 2000.04a
• /
• pp.509-511
• /
• 2000

An antifungal antibiotic was produced from Bacillus sp. YJ-63, and antibiotic was purified to a homogeneity by butanol extraction, Silica-gel column chromatography, Sephadex LH-20 gel filtration column chromatography and HPLC. The purified antibiotic showed one spot on Thin Layer Chromatography, which was negative to ninhydrin and positive to iodine. This finding indicated that the antibiotic was a cyclopeptide structure. UV absorption spectrum of the antibiotic in methanol was maximal at 277 nm, which corresponded to the spectrum for all of the Iturin antibiotic. The antibiotic was stable up to $121^{cdot}C$ and in the range of pH $3.O{\sim}l2.0$ with a stable of ${\alpha}-amino$ acid and ${beta}-amino$ acid, and showed high activity for fungi and yeasts,

• Journal of Integrative Natural Science
• /
• v.3 no.1
• /
• pp.24-27
• /
• 2010

Multi-functionalized rugate porous silicon (PSi) for biosensor was developed by hydrosilylation with silole and its further reaction with biotin groups. PSi was generated by an electrochemical etching of silicon wafer in aqueous ethanolic HF solution PSi prepared by using etching conditions showed that many sharp spectral lines can be obtained in the optical reflectivity spectrum. 1,1-hydrovinyl-2,3,4,5-tetraphenylsilole was obtained from the reaction of 1,1-dilithio-2,3,4,5-tetraphenyl-1,3-butadiene with dichlorovinylsilane. Multi-functionalized PSi with silole and biotin groups was characterized by UV-vis absorption spectroscopy, Ocean optics 2000 spectrometer, and fluorescence spectroscopy. Optical characteristics such as reflectivity and photoluminescence (PL) were observed. An increase of the reflection wavelength in the reflectivity spectrum by 20 nm was observed, indicative of a change in refractive indices induced by hydrosilylation of the silole and biotin groups to the rugate PSi. This red-shift was attributed to the replacement of some of the Si-H group of fresh rugate PSi with silole and biotin group.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.11a
• /
• pp.525-528
• /
• 1997

In this study, Eu(TTA)$_3$(phen) was synthesized and its films were prepared by vapor deposition method. Its films were characterized by UV-Vis absorption spectroscopy, Atomic Force Microscopy(AFM) and Photoluminescence(PL) measurements. Their electroluminescent(EL) characteristics were investigated by PL measurements, where a cell structure of glass substrate/ITO/Eu(TTA)$_3$(phen)/Al was employed. It was found that its films were well prepared without any decomposition and the film thickness could be controlled by adjusting the amount of Eu(TTA)$_3$(phen) in a boat. The EL spectrum of these films was almost the same as that of PL spectrum of these films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.07a
• /
• pp.831-834
• /
• 2000

Characteristics of organic light-emitting diodes(OLEDs) were studied with devices made by PECCP[poly(3,6-N-2-ethylhexyl carbazolyl cyanoterephthalidene)] Langmuir-Blodget(LB) films. The emissive organic material was synthesized and named PECCP, which has a strong electron donor group and an electron accepter group in main chain repeated unit. The LB technique was employed to investigate the identification of the recombination zone in the ITO/PECCP LB films/Alq$_3$/Al structure by varying the LB film thickness. PECCP was considered as an emissive layer and Alq$_3$was used as an electron-transport layer. We measured current-voltage(I-V) characteristics, UV/visible absorption, PL spectrum, and EL spectrum of those devises.