• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.450-451
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• 2007

Dot-patterned carbon nanotube (CNT) emitters with excellent field emission properties were fabricated using photosensitive CNT paste. We carried out a parametric study on the compositions and the fabrication processes of the paste, in particular, by ball milling CNTs, which were optimized in terms of dot shapes and their field emission characteristics. The ball milling process improved the field emission current of the dot-patterned CNT emitters several times higher than that of the non-milled paste.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.153-156
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• 2005

In this study, we have investigated transient properties of top emission organic light emitting diode (OLED) with a red electrophosphorescent dopant. The emission spectrum shows a strong peak at 620 nm accompanied with a small peak at 675 nm in the red region. Time evolution of electrophosphorescence reveals a decay time of 703 ms at a voltage pulse of 5 V in a device with an emitting area of 20 $mm^2$. Rise and delay times vary from 450 to 14 ms and 73 to 3 ms, respectively, as the voltage amplitude increases from 4.5 to 10 V. These results are compared with the red emitting device without an electron injection layer.

• Journal of Environmental Health Sciences
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• v.32 no.4 s.91
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• pp.292-303
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• 2006

The Volatile Organic Compounds(VOCs) are emitted from various sources and have lots of different form. Recently human are spending the many times at indoor area and indoor air pollution is issued the important social problem. The emission sources of indoor air pollutants are very various, also indoor building materials are composed of very complex chemical compounds, these indoor building materials discharge very much VOCs and other hazardous compounds. In this study, we performed the small chamber test to investigate the VOCs emission concentration and characteristics involving five kinds of the indoor building materials(furniture material, wooden floor, wall paper, paint and tile) under different conditions of four temperature and relative humidity as account of the air flow rate(AFR), air exchange rate(AER), loading factor and air velocity respectively. As the result, It was showed that building materials are emitted the highest VOCs concentration at the beginning of experiment and furniture material is emitted the highest VOCs concentration. Most of the materials were affected by temperature, but paint and tile material were affected by humidity.

• Journal of the Korea Furniture Society
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• v.18 no.3
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• pp.205-210
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• 2007

Particleboard(PB) is one of the most commonly used wood-based composite materials, which can be prepared by utilizing any kind of low grade wooden materials like waste wood which contains formaldehyde itself. Therefore, PB have been of considerable interest, in issues regarding the formaldehyde emission problems. Wood wastes are carbonized by the carbonization kiln at $800^{\circ}C$. Charcoal has been known as a formaldehyde adsorber. Thus, in this study, we fabricated PBs with carbonized waste particles cores, to examine the possibility of developing less formaldehyde emitting boards. The physical and mechanical properties were evaluated by Korean Standard (KS F 3104). The moisture content of PBs ranged from 6.76 to 8.36%. Internal bond strengths decreased with the increase in the content of carbonized core particles. Formaldehyde emission showed minimum value at 25% of carbonized core particles, but the emission values increased when the amount of carbonized cote particles increased. When 25% of carbonized core particles was used, PBs met KS F 3104 standard properties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.411-412
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• 2007

EL (electro luminescent) is generally studied as a large size plane light emitting device and flexible light source because of it's simple manufacturing process. In this experiment, we manufactured flexible white emitting light source using Ni-foil with blue phosphor and color change materials. With increasing the thickness of color change material, the luminance of white emission is increased and the color coordinate of white color was shifted to pure white of (0.317,0.328) by strong emission of color change materials excited by blue excitation spectra. Also the luminance level was 30% higher in white emitting light device than blue only light source.

• Journal of the Korea Institute of Building Construction
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• v.14 no.2
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• pp.187-194
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• 2014

With environmental regulations continuously being strengthened internationally the need to control environmental pollution and environmental load is emerging in Korea. The purpose of this study is to seek methods or using waste cementitious powder as an alternative raw material for limestone through the optimization of raw material and to quantitatively analyze the resulting reduction of $CO_2$ emission in order to contribute to solving the issue of waste, which is the biggest issue in relation to construction and global warming. The results of the study, show that waste cementitious powder can be used as an alternative raw material for limestone at OPC level, but it was also found that mixing fine aggregate cementitious powder into waste cementitious powder significantly affected the substitution rate for limestone with waste cementitious powder and the reduction of greenhouse gas. In particular, when fine aggregate cementitious powder was used at a rate of 0~20%, the substitution rate for limestone and the reduction in the rate of greenhouse gas emission was significantly reduced. It is thought that a technique to efficiently separate and discharge the fine aggregate cementitious powder mixed in waste cementitious powder needs to be developed in the future.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.277-278
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• 2009

We have studied an angular dependence of emission pattern of top-emssion organic light-emitting diodes (TEOLED). Device structure is Al(100nm)/TPD(40nm)/$Alq_3$(60nm)/LiF(0.5nm)/Al(2nm)/Ag(30nm). N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (TPD) and tris-(8-hydroxyquinoline) aluminium ($Alq_3$)were used as a hole transport layer and emission layer, respectively. Organic layers and cathode were thermally evaporated at $2\times10^{-5}$torr. The evaporation rate of the organic material was maintained to be $1.5\sim2.0{\AA}/s$, and that of metal layer to be $0.5\sim5{\AA}/s$. A transmittance of a cathode electrode(Al/Ag) in visible region is about 25~30%. In order to measure view-angle dependent intensity, electroluminenscence spectra of the device at each angle were integrated. Angle dependent emission spectra of the device do not show blue shift. Emission intensity of the device that the going straight characteristic is stronger the bottom-emission organic light-emitting diodes is shown.

• Korean Journal of Organic Agriculture
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• v.20 no.4
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• pp.475-490
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• 2012

Since 1997, Korean Ministry of Knowledge Economy and Ministry of Environment have established data on some 400 basic raw and subsidiary materials and process like energy, petro-chemical, steel, cement, glass, paper, construction materials, transportation, recycling and disposal etc by initiating establishment of LCI database. Regarding agriculture, Rural Development Administration has conducted establishment of LCI database for major farm products like rice, barley, beans, cabbage and radish etc from 2009, and released that they would establish LCI database for 50 items until 2020 later on. The domestic LCI database for seeds, seedling, agrochemical, inorganic, fertilizer and organic fertilizer etc is only at initial stage of establishment, so overseas LCI databases are brought and being used. However, since the domestic and overseas natural environments differ, they fall behind in reliability. Therefore, this study has the purpose to select organic farming materials, survey the production process for various types of organic farming materials and establish LCI database for the effects of greenhouse gas emitted by each crop during the process. As for selecting methods, in this study organic farming materials were selected in the method of direct observation of material and bottom-up method a survey method with focus on the organic farming materials admitted into rice production. For the basic unit of carbon emission amount by the production of 1kg of organic farming material, the software PASS 4.1.1 developed by Korea Accreditation Board under Ministry of Knowledge Economy was used. The study had the goal to ultimately provide basic unit to calculate carbon emission amount in executing many institutions like goal management system and carbon performance display system etc in agricultural sector to be conducted later on. As a result, emission basic units per 1kg of production were calculated to be 0.04968kg-$CO_2$ for oystershells, 0.004692kg-$CO_2$ for expanded rice hull, and 1.029kg-$CO_2$ for bordeaux mixture liquid.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.392-393
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• 2007

In this paper, we report the characteristics inorganic EL device with high dielectric constant materials of PMN, PZT. Fabricated EL device shows stable light emission even at 20kHz -400Volt without any break down failure. Brightness voltage curve of EL device is same with typical EL. As increasing applied voltage, the brightness increased linearly. From the results of Frequency and duty ratio variation, over 50% of brightness increment was seen. Luminous efficiency was increased upto 200V range and saturated over 200V by slow increasement of light emission. We got e bright stable emission of 1733 cd/m2 at the condition of Frequency 35 KHz, Duty 10%, 400V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04b
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• pp.69-72
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• 2002

We establish a visible light emission from porous polycrystalline silicon nano structure(PPNS). The PPNS layer are formed on heavily doped n-type Si substrate. 2um thickness of undoped polycrystalline silicon deposited using LPCVD (Low Pressure Chemical Vapor Deposition) anodized in a HF: ethanol(=1:1) as functions of anodizing conditions. And then a PPNS layer thermally oxidized for 1 hr at $900^{\circ}C$. Subsequently, thin metal Au as a top electrode deposited onto the PPNS surface by E-beam evaporator and, in order to establish ohmic contact, an thermally evaporated Al was deposited on the back side of a Si-substrate. When the top electrode biased at +6V, the electron emission observed in a PPNS which caused by field-induces electron emission through the top metal. Among the PPNSs as functions of anodization conditions, the PPNS anodized at a current density of $10mA/cm^{2}$ for 20 sec has a lower turn-on voltage and a higher emission current. Furthermore, the behavior of electron emission is uniformly maintained.