• Journal of the Korean Vacuum Society
• /
• v.6 no.1
• /
• pp.50-60
• /
• 1997

Undoped, cobalt-doped and erbium-doped $ZnAl_2S_4, ;ZnAl_2Se_4, ;CdAl_2S_4, ;and;CdAl_2Se_4$ single crystals were grown by the chemical transport reaction method. The crystal structures, the lattice constants, the optical energy gaps, and the photoluminescence properties of these single crystals were investigated. Also, the optical transition mechanisms by the impurities of cobalt and erbium were identified from these results.

• Journal of Korean Society of Water and Wastewater
• /
• v.27 no.1
• /
• pp.31-38
• /
• 2013

The degradation of 4-chlorophenol(4-CP) by various AOPs(Advanced Oxidation Processes) with continuous feeding of $H_2O_2$, including the ultraviolet/hydrogen peroxide, the Fenton and the photo-Fenton process has been investigated. The photo-Fenton process showed the highest removal efficiency for degradation of 4-chlorophenol than those of other AOPs including the Fenton process and the combined UV process with continuous feeding of $H_2O_2$. In the photo-Fenton process, the optimal experimental condition for 4-CP degradation was obtained at pH 3. Also the 4-CP removal efficiency increased with decreasing of the initial 4-CP concentration. 4-chlorocatechol and 4-chlororesorcinol were identified as photo-Fenton reaction intermediates, and the degradation pathways of 4-CP in the aqueous phase during the photo-Fenton reaction were proposed.

• Transactions on Electrical and Electronic Materials
• /
• v.13 no.6
• /
• pp.317-321
• /
• 2012

Poly[4,4'(3,3')-biphenylenevinylene-alt-2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene], 4,4'(3,3')-PBPMEH-PPV, and poly[4,4'(3,3')-biphenylenevinylene-alt-N-ethylhexyl-3,6-carbazolevinylene], 4,4'(3,3')-PBPCAR-PPV, of varying effective conjugation lengths, were synthesized by the well-known Wittig condensation polymerization between the appropriate biphenyl diphosphonium salts and dialdehyde monomers such as carbazole or dialkoxyphenyl dialdehyde. The conjugation lengths of the polymers were controlled by biphenyl linkages (4,4' or 3,3'). The resulting polymers were highly soluble in common organic solvents and exhibited good thermal stability up to $300^{\circ}C$. The synthesized polymers showed UV-visible absorbance and photoluminescence (PL) in the ranges of 314-400 nm and 430-507 nm, respectively. Carbazole and 3,3'-biphenyl containing 3,3'-PBPCAR-PPV showed a blue PL peak at 430 nm. A single-layer light-emitting diode was fabricated in a configuration of ITO/polymer/Al. Electroluminescence (EL) emission of 3,3'-PBPCAR-PPV was shown at 455 nm.

• YAKHAK HOEJI
• /
• v.45 no.6
• /
• pp.591-598
• /
• 2001

The photochemical study of Viscum album (Loranthaceae) led to the isolation of twelve compounds, lupeol (1), betulonic acid (2), betulinic acid (3), terminic acid (4), ursolic acid (5), $\beta$-sitosterol (6), $\alpha$- spinasterol (7), oleanolic acid (8) , 5-hydroxy-1- (4′-hydoxyphenyl) -7- (4"-hydroxyphenyl) -hepta-1- en-3-on (9), 2′-hydroxy -4′, 6′- dimethoxychalcone -4-O-glycoside (10) ,2′-hydroxy-4′, 6′-dimethoxychalcone -4-O- [apiosal(1longrightarrow12)]glucoside (11) and syringin (12). Their structures were established by chemical and spectroscopic methods. The cytotoxicity of the isolated compounds was evaluated by sulforhodamine B assay against five cultured human tumor cell lines.

• Journal of the Korean Chemical Society
• /
• v.36 no.4
• /
• pp.603-605
• /
• 1992

N-Substituted pyrroles were synthesized from 1,4-dichloro-1,4-dimethoxybutane and primary amines or amide in the presence of Amberlyst A-21 resin. Further reation of these N-substituted pyrroles with 1,4-dichloro-1,4-dimethoxybutane gave N-substituted carbazoles in moderate yields.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.4
• /
• pp.363-366
• /
• 2007

[ $Zn_2SiO_4:Mn$ ] green phosphors doped with $NH_4Cl$ and Al for PDP were synthesized by solid state reaction method. The luminescence of 532 nm in $Zn_2SiO_4:Mn$ phosphors was associated with $^4T_1{\to}^6A_1$ transition. Photoluminescence intensity of $Zn_2SiO_4:Mn$ doped with $NH_4Cl$ 15 mol% increased about two times as compared with that of $NH_4Cl$ non-doped sample. The color of the emission of Al-doped $Zn_2SiO_4:Mn$ phosphors changed to yellowish green.

• Bulletin of the Korean Chemical Society
• /
• v.17 no.7
• /
• pp.599-604
• /
• 1996

The synthesis is reported of p-nitrophenyl glycosides of D-galactose modified at C-4 with azido- (5), amino- (6) group and fluorine (13). 4-Azido-2,3,6-tri-O-benzoyl-4-deoxy-α-D-galactopyranosyl chloride and 2,3,6-tri-O-benzoyl-4-deoxy-4-fluoro-α-D-galactopyranosyl bromide were coupled with potassium p-nitrophenoxide in the presence of 18-crown-6 giving the corresponding p-nitrophenyl 4-azido-and 4-fluoro-4-deoxy-β-D-galactopyranoside derivatives. p-Nitrophenyl 4-amino-4-deoxy-β-D-galactopyranoside (6) was obtained by selective reduction of p-nitrophenyl 4-azido-4-deoxy-β-D-galactopyranoside (5) using 1,3-propane dithioltriethylamine. These galactoside analogs were slowly hydrolyzed in the increasing rate order of 5, 6 and 13 by β-galactosidase from Escherichia coli.

• Archives of Pharmacal Research
• /
• v.13 no.3
• /
• pp.257-260
• /
• 1990

Hantzch's type reaction of methyl acetopyruvate (2a), methyl 3-aminocrotonate (3) and 3-nitrobenzaldehyde (4) led to dimethyl 3-acetyl-6-methyl-4-(3'-nitrophenyl)-2, 5-dicarboxylate (5a) and methyl 2, 6-dimethyl-5-(1', 2'-dioxo-2'-methoxyethyl)-4-(3' nitrophenyl)- 2, 5-dicarboxylate (5a) and methyl 2, 6-dimethyl-5-(1', 2'-dioxo-2'methoxyethyl_4-(3' nitrophenyl)1, 4-dihydropyridine-3-carboxylate (6a) in 26.7 and 9.2% yield, respectively. On the other hand, methyl 2, 60dimethyl-4-(3'-nitrophenyl)-1, 4-dihydropyridine 3-carboxylate (9) was acylated by ethyl oxaly chloride to give methyl 2, 6-dimethyl-5-(1', 2'-dioxo-2'-ethoxyethyl)-4-(3'-nitrophenyl)-a, 4-dihydropyridine-3-carboxylate (6b) in 76.8% yield.

• Archives of Pharmacal Research
• /
• v.16 no.2
• /
• pp.164-167
• /
• 1993

Arylhydrazones of diethyl acetonedicarboxylate 3 was treated with fomaldehyde to 1-aryl-1, 4, 5, 6-tetrahyeheypyridazine derivatives 4a-f Cyclization of compound 4a-f by hydroxy-lamine afforded [3, 4-d] 1, 4, 5, 6-tetrahydropyridazine derivative 5a-f. Also, cyclization of compound 4c with semicarbazide gave pyrazolote [4, 3-c] pyridazine 6. On the other hand compound 3 reacted with ethylothofomate to give diethyl-1, 4-dihydro-1-arypyridazine-4-one-3, 5 dicaboxylate 7, which on treatment with hydrazine, semicarbazide and thiosemicarbazide gave pyridazine, amido and thioamido derivatives. The spectrl and antimicrobial data of these compounds 1-8 were studied.

• Archives of Pharmacal Research
• /
• v.26 no.9
• /
• pp.686-696
• /
• 2003

Ethyl (coumarin-4-oxy)acetate 1 was prepared through the reaction of 4-hydroxycoumarin with ethyl bromoacetate. Compound 1 was allowed to react with hydrazine hydrate to produce coumarin-4-oxyacetic hydrazide 2. The synthesis of N-(arylidene and alkylidene)-coumarin-4-oxyacetic hydrazones 3-20 was performed. The preparation of 2-substituted-3-[(coumarin-4-oxy) acetamido]thiazolidinones 21-26 and 2-[(coumarin-4-oxy )methyl]-4-acetyl-5-substituted-$\Delta^2$-1,3,4-oxadiazolines 27-33 was performed by the reaction of the hydrazones 3, 4, 7, 9, 12, 14 with mercaptoacetic acid and the hydrazones 3, 4, 5, 7, 12, 15, 16 with acetic anhydride, respectively. The antiviral activities, cytotoxicities and structure-activity relationship (SAR) towards different microorganisms of the prepared compounds were studied.