• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.91-94
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• 2010

The purpose of this study is to produce artificial lightweight aggregate. The properties of aggregate are deducted by analysing the plasticity of aggregate according to the addictive contents of $CaCO_3$ and $Al_2O_3$ on constant plastic temperature($1150^{\circ}C{\sim}1160^{\circ}C$) and the specific gravity, the percentage of water absorbtion. The density on the temperature of $1150^{\circ}C{\sim}1160^{\circ}C$ which results from that the plastic temperature of pottery stone is decreased by increasing the addictive contents of $CaCO_3$ and $Al_2O_3$ manufacturing artificial light weight aggregate using pottery stone is included in the arrange of light weight aggregate density. And the percentage of water absorbtion is 4.2~14% which is similar to or lower than existing artificial light weight aggregate. The unit volume weight is in inverse proportion to density and to increase addictive contents of flux.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.8
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• pp.711-715
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• 2007

Properties of organic light-emitting diodes (OLEDs) with aluminum-doped zinc oxide (ZnO:Al) anodes showed different behaviors from OLEDs with indium tin oxide (ITO) anodes according to driving conditions. OLEDs with ITO anodes gave higher current density and luminance in lower voltage region and better EL and power efficiency under lower current density conditions, However, OLEDs with ZnO:Al anodes gave higher current density and luminance in higher voltage region over about 8V and better EL and power efficiency under higher current density over $200mA/cm^2$. These seemed to be due to the differences in conduction properties of semiconducting ZnO:Al and metallic ITO. OLEDs with ZnO:Al anodes showed nearly saturated efficiency under high current driving conditions compared with those of OLEDs with ITO anodes. This meant better charge balance in OLEDs with ZnO:Al anodes. These properties of OLEDs with ZnO:Al anodes are useful in making bright display devices with efficiency.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.109-118
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• 1999

The aim of this study was to evaluate the optical density of laser fluorescence for detection of incipient caries. Prepared and polished bovine enamel specimens were demineralized in a STPP solution for varying periods of time between 3 hrs. and 60 hrs. with an area of sound enamel retained on each specimen. The randomized specimens were analyzed for optical density of enamel demineralization using laser fluorescence. The specimens were sectioned and examined lesion depth by polarizing light microscope. Results were analyzed statistically with SAS program. The results from this study can be summarized as follows: 1. Optical density measured by laser fluorescence and lesion depth measured by polarizing light microscope was increased as demineralization time was increased(p<0.001). 2. Between optical density measured by laser fluorescence and lesion depth measured by polarizing light microscope was correlated highly(${\gamma}{\geq}0.74956$, p<0.001). 3. Regressive equation was obtained in this study as follows. Y=[X-0.260851]/0.000271(R-square:0.5618, p<0.001) (X:DENSITY, Y:DEPTH) In summary, optical density measured by laser fluorescence would be within the range of possibility to quantitatively presume demineralization amount of incipient caries lesion

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.6
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• pp.1-7
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• 2012

Recently an optical diffusion of LED lamps has been studied actively. In this paper, the second lens applied to a cover of the LED lamp was analytically designed to having a wide angle distribution of light without diffuser characteristic by dispersing agent. In this process, We found a major factors that can help improve the performance of the lens. It is the refractive power of the lens, the Mie particle density of phosphor, and the arrangement of the LED. Through the final simulation, we can see the LED lamp is possible to get wide angle light distribution by proper source modeling and second lens designing. Also, we can see this simulated results are entirely consistent with measured data for light distribution. In this research, we present the shape of the second lens with wide angle distribution and derive the important factors for the second lens design.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1026-1029
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• 2002

We report the electric properties of organic light emitting diodes (OLEDs) by controlling the carrier density according to the crystalline of copper(II) phthalocyanine(CuPc) and the irradiation light intensity. OLEDs were constructed with indium tin oxaide (ITO)/CuPc/triphenyl-diamin (TPD)/tris-(8-hydroxyquinoline)aluminum (Alq3)/Al. The transport properties of OLEDs were changedby the heat-treatments of CuPc. The irradiation of red and blue light exciting CuPc, TPD and Alq3. And then we observed the carrier density of OLEDs.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.68-69
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• 2009

Heat Assisted Magnetic Recording (HAMR) is one of the most promising candidates for high density magnetic storages over 1 Tb/$in^2$ areal density. Since the precise light delivery to the head is a key factor to realize HAMR application, it is required to establish the light delivery using micro laser module and micro actuator. For the careful control of micro actuator, a laser module was designed including laser diode, optical fiber, collimating lens, and fabricated V-groove substrate. In addition, the basic aligning method between the laser module and HAMR head was studied by the detection of current change in photo diode due to the amount of reflected light from the head.

• Applied Science and Convergence Technology
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• v.25 no.6
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• pp.133-137
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• 2016

The surface treatment of cover glass for conversion efficiency of photovoltaic cell is important to reduce reflectivity and to increase the incident light. In this work, random textured anti glare (RTAG) glass was prepared by wet surface coating method. Optical properties due to the changes of surface morphology of RTAG glass were compared and conversion efficiency of photovoltaic cell was researched. Grain size and changes of surface morphologies formed with surface etching time greatly affected optical transmittance and transmission haze. Current density (Jsc) were high at the condition when surface morphologies reflection haze were low and transmission haze were high. Jsc was $40.0mA/cm^2$ at glancing angle of $90^{\circ}$. Incidence light source was strongly influenced by surface treatment of cover glass at high incidence angle but was hardly affected light source at the low angle of incidence.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.2
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• pp.103-108
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• 2005

For more accurately describing the durations of the light and the dark phases of micro-algal cells over the whole light-dark cycle, and probing into the relationship between the liquid circulation time or velocity, the aeration rate and cell density, a series of experiments was carried out in 10 cm light-path flat plate photobioreactors. The results indicated that the liquid flow in the flat plate photobioreactor could be described by liquid dynamic equations, and a high biomass output, higher content and productivity of arachidonic acid, $70.10\;gm^{-2}d^{-1},\;9.62\%$ and 510.3 mg/L, respectively, were obtained under the optimal culture conditions.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.4
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• pp.69-78
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• 1998

Papers loaded with 10-40% $TiO_2$ by dry weight were calendered under the various combinations of calendering conditions such as calender type, linear pressure, and roll temperature. After being calendered, light scattering coefficient, surface roughness, density, and tensile strength of the papers were measured and the results were summerized as follows: 1. To increase the light scattering coefficient of $TiO_2$-highly-loaded paper further by calendering, the calender roll pressure and temperature should be kept low. Under these conditions, the physical strength of the paper was not significantly affected. 2. At low roll temperature, soft nip calender and machine calender type showed the same relationship between paper density and its roughness. At high roll temperature, soft nip calender type gave much lower roughness than machine calender type at the same density. 3. At high roll temperature of both calenders, the density as well as the tensile strength of the TiO$_2$-loaded paper was increased significantly.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.211-217
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• 1990

This study was undertaken to determine (1) the usefulness of chromium intensifier to improve the dignostic quality of light radiograph; (2) the effect of chromium intensifier on density, contrast; and (3) the effect of various chemical concentrations on density. The following results obtained: 1. CHROMIUM INTENSIFIER is useful for intensifying and improving the diagnostic quality of a light dental radiograph. 2. The degree of intensification can be controlled by varying bleaching time, repeating the processing, varying the proportions of the potassium bicarbonate and hydrochloric acid solutions. 3. The image produced is black and permanent. 4. The intensifier increases density and contrast.