• Title/Summary/Keyword: UV-absorption

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Synthesis and Structural Characterization of Transition Metal Complex with N,N'-bis-[2(S) -pyrrolidinylmethyl]phenylene-1,2-diamine (N,N'-Bis[2(S)-2-pyrrolidinylmethyl]phenylene-1,2-diamine를 배위하는 전이금속 착물의 합성 및 구조적 특성)

  • Kim, Dong-Yeub
    • Journal of the Korean Society of Industry Convergence
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    • v.1 no.1
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    • pp.43-49
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    • 1998
  • The SS-phpm 4HCl(N,N'-bis-[2(S)-pyrrolidinylmethyl]phenylene-l,2-diamine-4-Hydrochloride) ligand having stereospecificity has been prepared and reacted with trans-[$Co(pyridine)_4Cl_2]$Cl. The resultants are purple crystals, which are identified to be ${\Delta}$-cis-${\beta}$-[$Co(SS-phpm)Cl_2$]Cl by elemental analysis and UV/Vis- and CD-absorption spectra, The conformation of SS-phpm in ${\Delta}$-cis-${\beta}$ complex is ${\delta}$ ${\varepsilon}$ ${\lambda}$ (SSSS) for each of the five-membered chelated ring. Futhermore, according to orientation of secondary amine, total strain energy on each isomers was calculated by molecular mechanics(MM) to verify structural characterization and spectral data. As the result, the most stabilized isomer was ${\Delta}$-cis-${\beta}$(SSSS). The value of total strain energy(U) of ${\Delta}$-cis-${\beta}$(SSSS) isomer was 63.21 kcal/mol, respectively.

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Simultaneous Analysis of the Coloring Compounds in Indigo, Phellodendron bark, and Madder Dye Using HPLC-DAD-MS

  • Ahn, Cheunsoon;Zeng, Xia;Obendorf, S. Kay
    • Journal of the Korean Society of Clothing and Textiles
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    • v.37 no.6
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    • pp.827-836
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    • 2013
  • Indigotin, indirubin, berberine, palmatine, alizarin, and purpurin are major pigments of indigo plant, Phellodendron bark, and madder. The six pigments were examined using the HPLC-DAD-MS instrument for the purpose of the simultaneous detection of the pigments in a single sample run. The HPLC-DAD-MS method examined the individual pigment solutions in DMSO, a solution containing 6 pigments, and the DMSO extract of the silk dyed with a dye solution of 5 pigments excluding indirubin. The retention times of the HPLC chromatograms, ${\lambda}_{max}$ of the uv-vis absorption bands in the DAD analyses, and the molecular ions detected for the compound peaks in the MSD analyses were consistent throughout the analyses of individual pigment solutions, mixed pigment solutions, and dye extracted from silk dyeing. The developed instrumental method of the simultaneous detection of six pigments can identify dye in an exhumed textile if the textile is dyed using any one (or multiple) pigments of indigo, Phellodendron bark, or madder plant.

A facile chemical synthesis of a novel photo catalyst: SWCNT/titania nanocomposite

  • Paul, Rima;Kumbhakar, Pathik;Mitra, Apurba K.
    • Advances in nano research
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    • v.1 no.2
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    • pp.71-82
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    • 2013
  • A simple chemical precipitation technique is reported for the synthesis of a hybrid nanostructure of single-wall carbon nanotubes (SWCNT) and titania ($TiO_2$) nanocrystals of average size 5 nm, which may be useful as a prominent photocatalytic material with improved functionality. The synthesized hybrid structure has been characterized by transmission electron microscopy (HRTEM), energy-dispersive X-ray analysis (EDAX), powder X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. It is clearly revealed that nearly monodispersed titania nanocrystals (anatase phase) of average size 5 nm decorate the surfaces of SWCNT bundles. The UV-vis absorption study shows a blue shift of 16 nm in the absorbance peak position of the composite material compared to the unmodified SWCNTs. The photoluminescence study shows a violet-blue emission in the range of 325-500 nm with a peak emission at 400 nm. The low temperature electrical transport property of the synthesized nanomaterial has been studied between 77-300 K. The DC conductivity shows semiconductor-like characteristics with conductivity increasing sharply with temperature in the range of 175-300 K. Such nanocomposites may find wide applications as improved photocatalyst due to transfer of photo-ejected electrons from $TiO_2$ to SWCNT, thus reducing recombination, with the SWCNT scaffold providing a firm and better positioning of the catalytic material.

Enantiomer Separation of Chiral Amino Alcohols as 9-anthraldimine Derivatives on Coated and Covalently Bonded Chiral Stationary Phases Based on Polysaccharide Derivatives by High Performance Liquid Chromatography (고성능 액체 크로마토그래피에 의한 다당 유도체를 기초로 한 흡착되거나 공유결합된 키랄 고정상에서 키랄 아미노 알코올의 안트르알디민 유도체의 광학분리)

  • Xu, Wen Jun;Jin, Jing Yu;Lee, Won-Jae
    • KSBB Journal
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    • v.26 no.4
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    • pp.323-327
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    • 2011
  • The convenient derivatization method of chiral amino alcohols as 9-anthraldimine Schiff base derivatives for chiral resolution was developed and the liquid chromatographic enantiomer separation of chiral amino alcohols as 9-anthraldimine derivatives was investigated on several coated and covalently bonded polysaccharide-derived chiral stationary phases (CSPs). In general, the performance of Chiralcel OD-H (or Chiralcel OD) (${\alpha}$ = 1.24-2.89), the coated CSP derived from cellulose derivative was superior to the other CSPs for resolution of 9-anthraldimine derivatives of several amino alcohols. The results of enantioseparation depending on the structure of 9-anthraldimine analytes like the steric bulky group and the polar moiety etc were discussed. The analytical method was applied to measure the enantiomeric purity of commercially available chiral amino alcohols. It is expected that the convenient analytical method will be very efficient for determination of enantiomeric purity of amino alcohols as 9-anthraldimine Schiff base derivatives with strong UV absorption.

Interfacial Natures and Controlling Morphology of Co Oxide Nanocrystal Structures by Adding Spectator Ni Ions

  • Gwag, Jin-Seog;Sohn, Young-Ku
    • Bulletin of the Korean Chemical Society
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    • v.33 no.2
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    • pp.505-510
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    • 2012
  • Cobalt oxide nanostructure materials have been prepared by adding several concentrations of spectator Ni ions in solution, and analyzed by electron microscopy, X-day diffraction, calorimetry/thermogravimetric analysis, UV-vis absorption, Raman, and X-ray photoelectron spectroscopy. The electron microscopy results show that the morphology of the nanostructures is dramatically altered by changing the concentration of spectator ions. The bulk XRD patterns of $350^{\circ}C$-annealed samples indicate that the structure of the cobalt oxide is all of cubic Fd-3m $Co_3O_4$, and show that the major XRD peaks shift slightly with the concentration of Ni ions. In Raman spectroscopy, we can confirm the XRD data through a more obvious change in peak position, broadness, and intensity. For the un-sputtered samples in the XPS measurement process, the XPS peaks of Co 2p and O 1s for the samples prepared without Ni ions exhibit higher binding energies than those for the sample prepared with Ni ions. Upon $Ar^+$ ion sputtering, we found $Co_3O_4$ reduces to CoO, on the basis of XPS data. Our study could be further applied to controlling morphology and surface oxidation state.

Chain Length Effect of Dialkoxynaphthalene End-Capped Divinylbenzene for OTFT

  • Kim, Ran;Yun, Hui-Jun;Yi, Mi-Hye;Shin, Sung-Chul;Kwon, Soon-Ki;Kim, Yun-Hi
    • Bulletin of the Korean Chemical Society
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    • v.33 no.2
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    • pp.420-425
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    • 2012
  • The new organic semiconductors which are composed of divinylbenzene core unit and alkoxynaphthalene on both sides, 1,4-bis-2-(6-octyloxy)naphthalen-2-ylvinylbenzene (BONVB), 1,4-bis-2-(6-decyloxy)naphthalen-2-ylvinylbenzene (BDNVB) and 1,4-bis-2-(6-dodecyloxy)naphthalen-2-ylvinylbenzene (BDDNVB) were synthesized by Wittig reaction. The structures of obtained BONVB, BDNVB and BDDNVB were confirmed by FT-IR and mass spectroscopy. UV-absorption of thin film showed H-aggregates and J-aggregates due to closely packed structure between adjacent molecules. The characterization of vacuum-evaporated films by Xray diffraction (XRD) and atomic force microscopy (AFM) showed that the chain length of alkoxy group affects the crystallinity and morphology. BONVB with octyloxy group showed the mobility of $0.011cm^2/V{\cdot}s$, on/off ratio of $1.31{\times}10^5$, and a subthreshold slope of 0.93 V.

Studies on Antibacterial Activity of Lactics (유산균(乳酸菌)의 항생작용(抗生作用)에 관(關)한 연구(硏究))

  • Kim, Dong Shin
    • Current Research on Agriculture and Life Sciences
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    • v.1
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    • pp.169-177
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    • 1983
  • 1. At selected time intervals, viable cell plate counts were run. After the 12 hours incubution the number of viable cells was maximum. 2. The morphology of L. acidophilus in tomato juice was thicker rods than those of in milk media. 3. In the assay of antimicrobial activity; (1) The antimicrobial activity of acidophilus tomato juice showed bigger inhibitory zone than acidophilus milk in the well-cup assay technique. (2) The inhibitory zone against Shigella dysenteriae was the biggest among the other pathogenic organisms in the disc assay. 4. The antimicrobial activity of sephadex G-50 gel filtration chomatography showed in the 5th fraction. 5. The spectra of ultraviolet absorption exhibited around maximum peak at 270nm.

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Effect of thermal treatment on spray deposited CdTe thin films (스프레이 증착법을 이용한 CdTe박막의 열처리에 따른 특성 분석)

  • Lee, Jinyoung;Hwang, Sooyeun;Lee, Taejin;Ryu, Siok
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.49.2-49.2
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    • 2010
  • Polycrystalline CdTe thin films for solar cell continues to be a promising material for the development of cost effective and reliable photovoltaic processes. The two key advantages of this material are its high optical absorption coefficient and its near ideal band gap for photovoltaic conversion efficiency of 1.4-1.5 eV. In this study we made the CdTe thin films for solar cell application which was deposited on the glass substrates using a modified chemical spray method at low temperature. This process does not require the sophisticated and expensive vacuum systems. The prepared CdTe films were characterized with the aid of scanning electron microscope (SEM), UV-visible spectrophotometer, and X-ray diffraction spectrometer (XRD). Following are results of a study on the "Human Resource Development Center for Economic Region Leading Industry" Project, supported by the Ministry of Education, Science & Tehnology(MEST) and the National Research Foundation of Korea(NRF).

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Synthesis and Characterization of Oligomers Composed of Alternating 2,5-Bis(ethynylenedimethylsilylene)thienylene and Arylene Units

  • Kwak, Young-Woo;Lee, Kyung-Koo;Cha, Seung-Hun;Lee, Sang-Koo;Lee, In-Sook;Park, Yong-Tae;Lee, Jae-Keun;Yoh, Soo-Dong;Kim, Woo-Sik
    • Bulletin of the Korean Chemical Society
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    • v.24 no.4
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    • pp.479-483
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    • 2003
  • The reactions of 2,5-bis(ethynyldimethylsilyl)thiophene (1) with aromatic dihalides(1,4-dibromobenzene, 4,4'- dibromobiphenyl, 9,10-dibromoanthracene, 2,5-dibromopyridine, 2,5-dibromothiophene, and 2,6-diiodo-4- nitroaniline) were carried out in the presence of a $[(PPh_3)_2PdCl_2]$-CuI catalyst in refluxing triethylamine to give poly{[2,5-bis(ethynylenedimethylsilylene)thienylene](arylene)} (2-7) with molecular weights of 2200-7400. The oligomers reveal characteristic absorption in the UV/visible region. The thermal behavior of 2-7 was examined by thermogravimetric analysis in an argon atmosphere.

Synthesis of Co(II), Ni(II) and Cu(II) Complexes from Schiff base Ligand and Reactivity Studies with Thermosetting Epoxy Resin

  • Lakshmi, B.;Shivananda, K.N.;Prakash, Gouda Avaji;Rama, Krishna Reddy K.;Mahendra, K.N.
    • Bulletin of the Korean Chemical Society
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    • v.32 no.5
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    • pp.1613-1619
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    • 2011
  • A hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) containing Co(II), Ni(II) and Cu(II) ions was prepared by curing N-MPGE and tetradentate Schiff base Co(II), Ni(II) and Cu(II) complexes. The curing polymerization reaction of N-MPGE with metal complexes as curing agents was studied. The cured samples were studied for thermal stability, chemical (acid/alkali/solvent) and water absorption resistance and homogeneity of the cured systems. The tetradentate Schiff base, 3-[(Z)-2-piperazin-1-yl-ethylimino]-1,3-dihydro indol-2-one was synthesized by the condensation of Isatin (Indole-2, 3-dione) with 1-(2-aminoethyl)piperazine (AEP). Its complexes with Co(II), Ni(II) and Cu(II) have been synthesized and characterized by microanalysis, conductivity, Uv-Visible, FT-IR, TGA and magnetic susceptibility measurements. The spectral data revealed that the ligand acts as a neutral tetradentate Schiff base and coordinating through the azomethine nitrogen, two piperazine nitrogen atoms and carbonyl oxygen.