• Bulletin of the Korean Chemical Society
• /
• v.28 no.11
• /
• pp.2089-2092
• /
• 2007

Tantalum-containing metal oxides, well known for their efficiency in water splitting and H2 production, have never been used in visible light driven photodecomposition of H2S and H2 production. The present work is an attempt in this direction and investigates their efficiency. A mixed metal oxide, ZnFe2Ta2O9, with the inclusion of Fe2O3 to impart color, was prepared by the conventional ceramic route in single- and double-calcinations (represented as ZnFe2Ta2O9-SC and ZnFe2Ta2O9-DC respectively). The XRD characterization shows that both have identical patterns and reveals tetragonal structure to a major extent and a minor contribution of orthorhombic crystalline system. The UV-visible diffuse reflection spectra demonstrate the intense, coherent and wide absorption of visible light by both the catalysts, with absorption edge at 650 nm, giving rise to a band gap of 1.9 eV. Between the two catalysts, however, ZnFe2Ta2O9-DC has greater absorption in almost the entire wavelength region, which accounts for its strong brown coloration than ZnFe2Ta2O9-SC when viewed by the naked eye. In photocatalysis, both catalysts decompose H2S under visible light irradiation (λ ≥ 420 nm) and produce solar H2 at a much higher rate than previously reported catalysts. Nevertheless, ZnFe2Ta2O9-DC distinguishes itself from ZnFe2Ta2O9-SC by exhibiting a higher efficiency because of its greater light absorption. Altogether, the tantalum-containing mixed metal oxide proves its efficient catalytic role in H2S decomposition and H2 production process also.

• Journal of Photoscience
• /
• v.9 no.2
• /
• pp.25-28
• /
• 2002

The chicken pineal gland has been used for studies on the circadian clock, because it retains an intracellular phototransduction pathway regulating the phase of the intrinsic clock oscillator. Previously, we identified chicken clock genes expressed in the gland (cPer2, cPer3, cBmal1, cBmal2, cCry1, cCry2, and cClock), and showed that a cBMALl/2-cCLOCK heteromer acts as a regulator transactivating cPer2 gene through the CACGTG E-box element found in its promoter. Notably, mRNA expression of cPer2 gene is up-regulated by light as well as is driven by the circadian clock, implying that light-dependent clock resetting may involve the up-regulation of cPer2 gene. To explore the mechanism of light-dependent gene expression unidentified in animals, we first focused on pinopsin gene whose mRNA level is also up-regulated by light. A pinopsin promoter was isolated and analyzed by transcriptional assays using cultured chicken pineal cells, resulting in identification of an 18-bp light-responsive element that includes a CACGTG E-box sequence. We also investigated a role of mitogen-activated protein kinase (MAPK) in the clock resetting, especially in the E-box-dependent transcriptional regulation, because MAPK is phospholylated (activated) in a circadian manner and is rapidly dephosphorylated by light in the gland. Both pulldown analysis and kinase assay revealed that MAPK directly associates with BMAL1 to phosphorylate it at several Ser/Thr residues. Transcriptional analyses implied that the MAPK-mediated phosphorylation may negatively regulate the BMAL-CLOCK-dependent transactivation through the E-box. These results suggest that the CACGTG E-box serves not only as a clock-controlled element but also as a light-responsive element.

• The Bulletin of The Korean Astronomical Society
• /
• v.41 no.1
• /
• pp.41.3-42
• /
• 2016

New CCD photometric observations of GX Aur have been made between 2004 and 2015. Our light curves are the first ever compiled and display the variable O'Connell effect. The light variations are satisfactorily modeled by including time-varying cool-spots on the component stars. Our light curve synthesis indicates that the eclipsing pair is an A-type contact binary with parameters of i = 81.1 deg, ${\Delta}T=36K$, q = 0.950 and f = 46%. Including our 25 timing measurements, a total of 83 times of minimum light spanning about 66 yr were used for a period study. It was found that the orbital period of GX Aur has varied due to two periodic oscillations superposed on an upward-opening parabolic variation. The long-term period increase rate is deduced as $+9.636{\times}10^{-10}d\;yr^{-1}$, which can be produced as a mass transfer from the secondary star to the primary at a rate of $3.136{\times}10^{-6}M_{\odot}\;yr^{-1}$, among the largest rates for contact systems. The periods and semi-amplitudes of the two periodic variations are about $P_3=8.7yr$ and $P_4=21.2yr$, and $K_3=0.011d$ and $K_4=0.017d$, respectively. The most reasonable explanation for both cycles is a pair of light-travel-time effects driven by the possible existence of an unseen third and fourth components with projected masses of $M_3=0.91M_{\odot}$ and $M_4=1.09M_{\odot}$ in eccentric orbits of $e_3=0.13$ and $e_4=0.73$. Because no third light was detected in the light curve synthesis, each circumbinary object could be a compact star or a binary itself.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2003.12a
• /
• pp.304-304
• /
• 2003

• Journal of Plant Biology
• /
• v.36 no.3
• /
• pp.293-296
• /
• 1993

Effects of dark treatment and N1-dichlorophenyl-N3-dimethylurea (DCMU) on the desaturation of galactolipids of Dunaliella salina were investigated to see whether light-driven photosynthetic electron transport is involved in in vivo desaturation of galactolipids. The incorporation of radioactive fatty acid precursors ([14C]lauric acid) into galactolipids, mainly composed of prokaryotic molecular species, was most affected among different polar lipid classes by both treatments. The analysis of specific radioactivities of individual galactolipid molecular species revealed that their synthesis was greatly inhibited by the treatments except for eukaryotic molecular species, 18 : 3/ 18 : 3 digalactosyldiacylglycerol, whose desaturation occurs in endoplasmic reticulum.

• Journal of Photoscience
• /
• v.9 no.2
• /
• pp.320-322
• /
• 2002

Archaerhodopsin (aR), a light-driven proton pump found in HaIonubrum sp. aus-l, was crystallized into an octahedral crystal belonging to the space group P4$_3$2$_1$2. It is shown that aR is composed of7 helical segments and an anti-para1leI ${\beta}$ sheet. The main-chain sIrudure of aR is nearly identical to that of bacteriorhodopsin, but a significant structural difference is observed in the protein surface, especially at lipid binding sites.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1195_1196
• /
• 2009

Light rail transit is classified to rubber-tired LRT, lear induction motor LRT, steel wheel LRT, monorail and tramway. LRT except for tramway are usually operated without driver and tramway are driven depending on driver's sight like usual car. LRT, which is one type of urban guided transit, shall be operated according to domestic "Operational Regulation for Urban Guided Transit" but existing regulation does not contain the safety related codes for driverless operation. In this paper, we investigate "IEC 62267 : Railway Application-Safety Requirements for Automated Urban Guided Transit" and compensate for existing operational regulation by referring to international standard and operational rule of commercial line.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.523-527
• /
• 1991

A rubber pneumatic controlled actuator is a new actuator. It is very light With a high power-to-weight ratio. In this thesis, a control method for a two link robot arm using the rubber actuator is developed. The structure of the servo control is made up of two sections. The position control is performed by PID feedback control. The air pressure is controlled by Servo Valve Unit driven by PWM and the control input is compensated by software operation. The numerical simulation of this control method to two link robot arm is presented to verify the performance of the closed loop system. The actual control of the real two link robot arm with rubber actuator is taken and its results are discussed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.1
• /
• pp.113-118
• /
• 2010

In This Paper, at the PSPICE model is presented by Piezoelectric Transformer and CCFL and equivalent circuit of fluorescent light. Highly effective fluorescent light release for next generation is developed for 35W supremacy model three wave length T5 fluorescent lamps. Lighting a candle experiment of T5 fluorescent lamps is carried out by employing Piezoelectric Transformer power-factor improvement circuit and inverter. PLL method is used for supplying a correct frequency of Piezoelectric Transformer operating.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.555-558
• /
• 2017

In this paper, we designed a power supply AC LED driving device which can display uniform power consumption and light efficiency even when AC power of different size is applied. By setting input voltages and deviations of different sizes, it is confirmed that the electric light characteristics are the same at two input voltages. In addition, according to peak voltage of AC power, improper lighting caused in specific LED section is improved, and LED lighting of all sections is implemented in all commercial AC input voltage.