• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.17 no.1
• /
• pp.35-40
• /
• 2007

Cobalt ($Co^{2+}$) doped yttria stabilized cubic zirconia (YSZ, $Y_2O_3\;:\;25{\sim}50wt%$) single crystals grown by a skull melting method were heat-treated in $N_2\;at\;1000^{\circ}C$ for 5 hrs. The reddish brown single crystals were changed into either violet or blue color, respectively. Before and after heat treatment, the Co-doped YSZ crystals cut for wafers (${\phi}6.5{\times}t\;2mm$) and round brilliant (${\phi}10mm$). The optical and structural properties were examined by UV-VIS spectrophotometer and XRD. These results are analyzed absorption by $Co^{2+}\;(^4A_2(^4F)\to{^4P})\;and\;Co^{3+}$, change of energy gap and lattice parameter.

• Journal of Information Display
• /
• v.6 no.2
• /
• pp.25-29
• /
• 2005

The luminescent properties of $Eu^{3+}$ and $Sm^{3+}$ doped potassium tungstate phosphor are investigated. The $K_{4-3x}(WO_4)_2:Eu^{3+}\;_x,Sm^{3+}\;_y$ phosphor is produced by firing the mixed precursors, followed by re-firing with a flux. The re-firing process results in the defect-free surface and uniform growth of the particles. The strong absorption in the region of ultra violet light is observed due to the 4f-4f electron transitions of the $Eu^{3+}$ and $Sm^{3+}$ ions. The doping concentration of europium into potassium tungstate is relatively high, compared to other host materials. It is revealed that the crystal structure is a monoclinic with space group, C2/c. This crystal structure facilitated the $Eu^{3+}$ ions to be located with the Eu-Eu distance larger than 5 ${\AA}$ so that concentration quenching does not occur even at high doping concentration. The excitation spectrum could be adjusted by the introduction of the samarium. A small amount of the $Sm^{3+}$ ions that acts as a sensitizer increases the energy absorption peak around 405 nm.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.207-207
• /
• 2010

Both ZnO and GaN have excellent physical properties in optoelectronic devices such as blue light emitting diode (LED), blue laser diode (LD), and ultra-violet (UV) detector. The ZnO/GaN heterostructure, which has a potential to achieve the cost efficient LED technology, has been fabricated by using radio frequency (RF) sputtering, pyrolysis, metal organic chemical vapor deposition (MOCVD), direct current (DC) arc plasmatron, and pulsed laser deposition (PLD) methods. Among them, the PLD system has a benefit to control the composition ratio of the grown film from the mixture target. A 500-nm-thick ZnO film was grown by PLD technique on c-plane GaN/sapphire substrates. The post annealing process was executed at some varied temperature between from $300^{\circ}C$ to $900^{\circ}C$. The morphology and crystal structural properties obtained by using atomic force microscope (AFM) and x-ray diffraction (XRD) showed that the crystal quality of ZnO thin films can be improved as increasing the annealing temperature. We will discuss the post-treatment effect on film quality (uniformity and reliability) of ZnO/GaN heterostructures.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.8 no.2
• /
• pp.101-105
• /
• 2003

Recombinant bioluminescent bacteria were used to monitor and classify the to xicity of azo dyes. Two constitutive bioluminescent bacteria, Photobacterium phosphoreum and Es-Cherichia coli, E, coli GC2 (lac::luxCOABE), were used to detect the cellular toxicity of the azo dyes. In addition, four stress-inducible bioluminestent E. coli, DPD2794 (recA::luxCDABE), a DNA damage Sensitive strain; DPD2540 (fabA::luxCDABE), a membrane damage sensitive strain; DPD2511 (katG::luxCDABE), an oxidative damage sensitive strain; and TV1061 (grpE::luxCDABE), a protein damage sensitive strain, were used to provide information about the type of toxicity caused by crystal violet, the most toxic dye of the 16 azo dyes tested. These results suggest that azo dyes result in serious cellular toxicity in bacteria, and that toxicity monitoring and classific ation of some azo dyes, In the field, may be possible using these recombinant bioluminescent bacteria.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.17 no.1
• /
• pp.18-28
• /
• 1991

Spectral behaviors of cationic dye, crystal violet(CV), in aqueous solution and with varying concentrations of Triton X-100(TX-100), sodium dodecylsulfate (SDS) and cetyl trimethyl amonium bromide(CTAB) were studied. The characteristic changes of the absorption spectra observed in the dye-SDS interacting systems with the SDS concentration are analyzed. The behaviors of both a- and J-bands of the each componet dye suggest that the following four sequential steps are occurring : the formation of dye-SDS complex, the stacking of the dye molecules arising from the association of the dye-SDS complex, breaking of the dye stacking due to the formation of micelles, redistribution of the dye molecules in the surface of micelles at high SDS concentration.

• Economic and Environmental Geology
• /
• v.13 no.2
• /
• pp.117-127
• /
• 1980

Molybdenum as by-products of Sangdong tungsten mine occurrs in the form of molybdenite in quartz vein. The molybdenum contents of scheelite in Sangdong ore bodies ranges from trace to 8%, therefore the scheelites show variable fluorescence colores under ultra-violet lamp (short wave). The fluorescence color are in order high content of molybdenum, yellow, white and blue. The yellow fluorescing scheelite is dominant in upper ore vein, otherwise the blue fluorescent variety is dominant in lower ore vein. The fluorescence color of scheelite in the main ore vein show zonal distribution becoming progressively more blue outerwards, contrary more yellow innerwards, and even in single scheelite crystal, simillar zonal pattern is observed, too. Molybdenite occurrs as flakes or elongated blades at the margins of the quartz vein only molybdenite bearing quartz veins but also other sulfides mineral bearing quartz veins have mainly blue flourescing scheelites. We suggest that the molybdenum contents of the early stage ore solution are progressively decreased by a subsequent crystallization of the yellow fluorescing scheelites.

• Journal of environmental and Sanitary engineering
• /
• v.6 no.1
• /
• pp.31-46
• /
• 1991

Aeromonas hydrophila which bacause various diseases in human also infects fresh water fish, severly damaging the fishing industries. To prevent disease in humans and reduce damaging on the fishing industries, We have examined several characteristics of Aeromonas hydrophila and obtained the following results. All of the strains gave a posive voges-proskauer, methyl-red, salicin and esculin reaction. Seventeen(94.4%) A. hydrophila strains presented the phenotype SP-PAB- in autoagglut-ination test, but only strain AH 997 showed $SP^{+}PAB^{+}$. in autoagglut ination test, but only strain AH 997 $SP^{+}PAB^{+}$ All of the strains took up the censored to various degrees. Three of 18 strains showed positive reaction in crystal violet binding test. Hemolytic activity ranged from titers of 0 to 1/256. Seven of the 17(38.8%) A. hydrophila strains were positive in sucking mouse assay. Cytotoxin activity on vero and RK cells was displayed various titers.(1/2-1/1024)

• Journal of Information Display
• /
• v.11 no.1
• /
• pp.12-16
• /
• 2010

The effect of the crystallization and activated annealing of Si films using an excimer laser and the new CW blue laser are described and compared with furnace annealing for application in advanced TFTs and for future applications. Pulsed excimer laser annealing (ELA) is currently being used extensively as a low-temperature poly-silicon (LTPS) process on glass substrates as its efficiency is high in the ultra-violet (UV) region for thin Si films with thickness of 40-60 nm. ELA enables extremely low resistivity relating to high crystallinity for both the n- and p-type Si films. On the other hand, CW blue laser diode annealing (BLDA) enables the smooth Si surface to have arbitral crystal grains from micro-grains to an anisotropic huge grain structure only by controlling its power density. Both annealing techniques are expected to be applied in the future advanced TFT systems.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07b
• /
• pp.1510-1513
• /
• 2005

The luminescent properties of $Eu^{3+}$ and $Sm^{3+}$ doped potassium tungstate phosphor were investigated. The $K_{4-3x}(WO_4)_2:Eu_x$, $Sm_y$ phosphor was produced by firing the mixed precursors, followed by re-firing with a flux. The re-firing process provided the clean surface to the particles. The excitation spectra showed that the strong absorption in the region of ultra violet light occurred due to the high europium doping concentration. The incorporation of europium to potassium tungstate was easier, compared to other host materials. The excitation spectra could be controlled by the small addition of samarium. The increase of energy absorption around 405nm was assigned to the $Sm^{3+}$ ions. The comparison between real x-ray diffraction and simulated one revealed that the crystal structure of $K_{4-3x}(WO_4)_2:Eu_x,Sm_y$ phosphor is monoclinic with a space group, C2/c.

• Korean Journal of Materials Research
• /
• v.17 no.7
• /
• pp.352-357
• /
• 2007

Since a pattern defects "repair" system using a diode pumped solid state laser for Flat Panel Display (FPD) was suggested, a lot of laser systems have been explored and developed for mass-production microfabrication process. A maskless lithography system using 405 nm violet laser and Digital Micromirror Device (DMD) has been developed for PDP and Liquid Crystal Display (LCD) Thin Film Transistor (TFT) photolithography process. In addition, a "Laser Direct Patterning" system for Indium Tin Oxide (ITO) for Plasma Display Panel(PDP) has been evaluated one of the best successful examples for laser application system which is applied for mass-production lines. The "heat" and "solvent" free laser microfabrications process will be widely used because the next-generation flat panel displays, Flexible Display and Organic Light Emitting Diode (OLED) should use plastic substrates and organic materials which are very difficult to process using traditional fabrication methods.