• Bulletin of the Korean Chemical Society
• /
• 제33권12호
• /
• pp.4059-4062
• /
• 2012

The effect of a conductive agent on the structural and electrochemical properties of $Li_4Ti_5O_{12}$(LTO) spinel was investigated through neutron diffraction during Li intercalation and electrochemical measurements. The charging process of LTO is known as transformation of the white $(Li_3)_{8a}[LiTi_5]_{16d}O_{12}$ into a dark-colored $(Li_{3-X})_{8a}[Li_{X+Y}]_{16c}[LiTi_5]_{16d}O_{12}$ by incorporating the inserted Li into octahedral 16c sites, and the Li in tetrahedral 8a sites shifted to 16c sites. The occupancy of the tetrahedral 8a site varied with the existence of carbon in the electrode. Without carbon, the lattice parameter and cell volume of LTO decreased more notably than in the carbon-containing LTO electrode during Li insertion process. These phenomena might be attributed that the Li occupancy of the tetrahedral 8a of the LTO electrode without carbon was less than that of the carbon-containing LTO electrode.

• 분석과학
• /
• 제9권1호
• /
• pp.72-77
• /
• 1996

감응제 rose bengal과 초감응제 $I^-$를 포함하는 광전기화학쎌을 이용하여 태양에너지를 전기적 에너지로 전환할 때 광전류는 안정화되고 지속적이지만 장시간의 광조사시에는 서서히 감소한다. 염료용액을 분광학적 및 전기화학적으로 분석한 결과 rose bengal과 $I^-$의 광촉매 반응에 의하여 $I_2$가 생성되고 $I_2$가 빛이 없는 조건하에서도 rose bengal과 반응하여 염료 농도를 감소 시키는것이 확인되었다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
• /
• pp.131-134
• /
• 2000

Electroluminescent[EL] from conjugated polymers has recently received great attention because polymer light-emitting diodes[LEDs] clearly have potential for applications such as large-area displays. The operation of polymer LEDs is based on double injection of electrons and holes from the electrodes, followed by formation of excitons whose radiative decay results in light emission at wavelength characteristic to the material In this paper, we fabricated the single layer EL device using poly(3-octylthiophene)[P3OT] as emitting material. The orange-red light was clearly visible in a dark room Maximum peak wavelength of EL spectrum saw at 640nm in accordance with photon energy 1.9eV. And we know that ionization energy of P3OT is 4.7eV from the cyclic voltammetry.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 추계학술대회 논문집
• /
• pp.260-263
• /
• 2007

The importance of natural light in building is known by all of us who experienced dark rooms. The sunlight system is very important from energy saving and human welfare point of view. The system consists of light-collecting module, light -transporting module and light-emitting module. The light-collection is used light reflection mirror, a prism for lighting bent, and lens for light condensing. The transportation of collected sunlight is used polished duct, tube, pipe and specially used fiber optic cable. This paper investigate research and development trends of sunlight system for advanced product.

• 천문학회보
• /
• 제43권1호
• /
• pp.62.2-62.2
• /
• 2018

From the gaussian, near scale-invariant density perturbations observed in the CMB to the late time clustering of galaxies, CDM provides a minimal theoretical explanation for a variety of cosmological data. However accepting this explanation, requires that we include within our cosmic ontology a vacuum energy that is ~122 orders of magnitude lower than QM predictions, or alternatively a new scalar field (dark energy) that has negative pressure. Alternatively, modifications to Einstein's General Relativity have been proposed as a model for cosmic acceleration. Recently there have been many works attempting to test for modified gravity using the large scale clustering of galaxies, ISW, cluster abundance, RSD, 21cm observations, and weak lensing. In this work, we compare various modified gravity models using cosmic shear data from the Deep Lens Survey as well as data from CMB, SNe Ia, and BAO. We use the Bayesian Evidence to quantify the comparison robustly, which naturally penalizes complex models with weak data support. In this poster we present our methodology and preliminary constraints on f(R) gravity.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.457-457
• /
• 2013

Current-voltage (I-V) measurements of crystalline silicon solar cells was conducted under dark conditions with the temperature range of 260 K~350 K. Using the calculation method, we extracted the crucial factors of ideality factor (n) and activation energy (Ea) to investigate the carrier conducting path in the space charge region (SCR) and the quasi-neutral region (QNR). Values of n were decreased with increasing temperature in both SCR and QNR. We also conformed that the value of Ea of SCR was larger than that of QNR about 0.4 eV. The temperature dependence of n indicates that the carrier conducting path is dominated by carrier recombination-generation in the SCR region than in the QNR region.

• Advances in Energy Research
• /
• 제3권1호
• /
• pp.45-57
• /
• 2015

This article is addressed to define a new composite electrode constituted by porous nickel and an array of highly ordered $TiO_2$ nanotubes obtained by a previous galvanostatic anodization treatment in an ethylene glycol solution. The electrochemical performances of the composite anode were evaluated in a photo-electrolyser, which showed good solar conversion efficiency with respect to the UV irradiance together with a reduction of energy consumption. Such a combination of materials makes our system simple and able to work both in dark and under solar light exposure, thus opening new perspectives for industrial-scale applications.

• 한국환경생물학회:학술대회논문집
• /
• 한국환경생물학회 2003년도 학술대회
• /
• pp.68-73
• /
• 2003

The possibility of using the alkaline protocol of the single cell gel electrophoresis (SCGE) assay as a method for detecting induced DNA damage has been studied for six major plants. The EMS was applied as a model genotoxic agent on young excised leaves of the tested crops for 18 h at 26$^{\circ}C$ in the dark. With increasing concentrations of 0 to 10 mM EMS, the DNA damage, expressed by the averaged median tail moment values, significantly increased in nuclei of all plants studied. As the results, no correlation between the diameter of nuclei and sensitivity to EMS treatment was observed. The data obtained demonstrate the feasibility of using the SCGE assay for detecting induced DNA damage in plants.

• Bulletin of the Korean Chemical Society
• /
• 제20권6호
• /
• pp.720-726
• /
• 1999

It has been proved by the semi-classical gauge invariant formulation (GIF) that the correct interaction operator for coupling the field-free material states with the radiation field must be the position form regardless of the gauge chosen for expressing the electromagnetic potentials, in accordance with the well-established principle of gauge invariance. The semi-classical GIF is now extended to the quantized radiation field interacting with matter by defining the energy operator for the quantized radiation field in the presence of matter. It will be shown in this paper that the use of the energy operator guarantees the position form of the interaction operator even in the Coulomb gauge, contrary to the conventional approach in which the dark material Hamiltonian is used to get the interaction operator of the momentum form. The multipolar Hamiltonian is examined in the context of the quantum mechanical gauge transformation.

• Journal of Korean Vacuum Science & Technology
• /
• 제3권2호
• /
• pp.116-120
• /
• 1999

Possible role of hydrogen atoms on the formation of microcrystalline silicon films was schematically investigated using a plasma enhanced chemical vapor deposition system. A layer-by-layer technique that can alternate deposition of ${\alpha}$-Si thin film and then exposure of H2 plasma was used for this end. The experimental process was extensively carried out under different hydrogen plasma times (t2) at a fixed number of 20 cycles in the deposition. structural properties, such as crystalline volume fractions and grain shapes were analyzed by using a Raman spectroscopy and a scanning electron microscopy. Electrical transports were characterized by the temperature dependence of the dark conductivity that gives rise to the calculation of activation energy (Ea). Optical absorption was measured using an ultra violet spectrophotometer, resulting in the optical energy gap (Eopt). Our experimental results indicate that both of the hydrogen etching and the structural relaxation effects on the film surface seem to be responsible for the growth mechanism of the crystallites in the ${\mu}$c-si films.