• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.05a
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• pp.341-346
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• 2004

In the present work, for various energy and electricity generating systems to be compared in view of integrated social impacts, nuclear, coal-fired, heavy oil-fired, and LNG, and hydroelectricity systems are considered as electricity generating options. The following assessment factors are selected: economic effect, health effect, environmental effect, and benefit at the national level. As a preliminary study, these factors are represented as power generation cost, estimated mortality, Carbon Dioxide gas emission, and fuel supply stability, respectively. For integrated representation of a multi-criteria decision-making (MCDM) problem, radar charts are introduced to facilitate a comparative recognition of estimates. In the near future, based on the estimates, a MCDM methodology for both qualitative and quantitative comparison will be developed.

• Particle and aerosol research
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• v.12 no.1
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• pp.21-26
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• 2016

In order to realize In-line and convenient measurement for solid-gas two phase flows, Light Transmission Fluctuation (LTF) based on the random variation of transmitted light intensity, light scattering theory and cross-correlation method was presented for online measurement of particle size, concentration and velocity. The statistical relationship among transmitted light intensity, particle size and particle number in measurement zone was described by Beer-Lambert Law. Accordingly, the particle size and concentration were determined from the fluctuation signal of transmitted light intensity. Simultaneously, the particle velocity was calculated by cross-correlation analysis of two neighboring light beams. By considering the influence of concentration variation in industrial applications, the improved algorithm based on spectral analysis of transmitted light intensity was proposed to improve measurement accuracy and stability. Therefore, the online measurement system based on LTF was developed and applied to measure pulverized coal in power station and raw material in cement plant. The particle size, concentration and velocity of powder were monitored in real-time. It can provide important references for optimal control, energy saving and emission reduction of energy-intensive industries.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.542-545
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• 2002

High performance organic electroluminescnet(EL) devices which are composed of organic thin multilayer films are fabricated. The basic structure is ITO/Emitting layer/LiF/Al in which have a blended emitting layer. The emitting layer is consisted of a host material(N,N' diphenyl-N,N' (3-methyl phenyl)-l,l'-biphenyl-4,4'diamine)(TPD)) and a guest emitting material(poly(3-hexylthiophehe)(P3HT)). We think that the energy transfer in blending layer occurred from TPD to P3HT. Red emitting multilayer EL devices were fabricated using tris(8-hydroxyqunolinate) aluminum$(Alq_3)$ as electron transport material. The device structure of ITO/blending layer(TPD+P3HT)$/Alq_3$/LiF/Al was employed. In the Voltage-current-luminance characteristics of multilayer device, the device tum on at the 2V and the luminance of $10{\mu}W/cm^2$ obtain at l0V. Red emission peak at 640nm was observed with this device structure. We have presented evidence that the excitation energy migration between a polymeric host and guest has to be explained. And by using multilayer, the red light emitting EL device enhances not only Voltage-current-luminance characteristic but also stability of device.

• Polymer(Korea)
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• v.35 no.5
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• pp.483-487
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• 2011

For the preparation of effective non-vascular drug eluting stent (DES), pullulan acetate (PA) was investigated as a coating material for polytetrafluorethylene (PTFE)-covered stent. PA was coated on PTFE-covered stent (PTFE-stent) by dip coating technique, and then its surface morphology, drug release behavior and cellular toxicity were tested. Field emission-scanning electron microscopy (FE-SEM) result indicated that its surface was smoother after PA coating without any cracking. The sustained release behavior of paclitaxel from PA-coated PTFE membrane was observed for 80 days. Also, the biological stability of paclitaxel in the membrane was confirmed by annexin V binding assays. Furthermore, the antitumor activity was demonstrated by an in vivo test against CT-26 murine colorectal tumors. From the results, we concluded that PA was expected as a useful coating material to design an effective non-vascular DES.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.105-110
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• 2012

A europium (III)-sensitized, spectrofluorimetric (FL) method is presented for the determination of sparfloxacin (SPAR) using an anionic surfactant, sodium dodecyl benzene sulphonate (SDBS). The method is based on the strong fluorescence (FL) enhancement of SPAR after the addition of $Eu^{3+}$ ions as fluorescence probes. The experimental results indicated that the FL intensity of the SPAR-$Eu^{3+}$ system was enhanced markedly by SDBS. The maximum FL emission signal was obtained at about 615 nm when excited at 372 nm. The experimental conditions that affected the FL intensity of the SPAR-$Eu^{3+}$-SDBS system were optimized systematically. The enhanced FL intensity of the system exhibited a good linear relationship with the SPAR concentration over the range of $1.5{\times}10^{-9}-1.2{\times}10^{-7}mol\;L^{-1}$ with a correlation coefficient (r) of 0.9987. The limit of detection ($3{\delta}$) was $4.15{\times}10^{-10}mol\;L^{-1}$ with a relative standard deviation (RSD) of 1.65%. This method was successfully applied for the determination of SPAR in pharmaceuticals, and human serum and urine samples with higher sensitivity, wide dynamic range and better stability. The possible interaction mechanism of the system is also discussed in detail by ultraviolet absorption spectra and FL spectra.

• Korean Journal of Materials Research
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• v.17 no.2
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• pp.73-80
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• 2007

For the sub-65 nm CMOS process, it is necessary to develop a new silicide material and an accompanying process that allows the silicide to maintain a low sheet resistance and to have an enhanced thermal stability, thus providing for a wider process window. In this study, we have evaluated the property and unit process compatibility of newly proposed composite silicides. We fabricated composite silicide layers on single crystal silicon from $10nm-Ni_{1-x}Co_x/single-crystalline-Si(100),\;10nm-Ni_{1-x}Co_x/poly-crystalline-\;Si(100)$ wafers (x=0.2, 0.5, and 0.8) with the purpose of mimicking the silicides on source and drain actives and gates. Both the film structures were prepared by thermal evaporation and silicidized by rapid thermal annealing (RTA) from $700^{\circ}C\;to\;1100^{\circ}C$ for 40 seconds. The sheet resistance, cross-sectional microstructure, surface composition, were investigated using a four-point probe, a field emission scanning probe microscope, a field ion beam, an X-ray diffractometer, and an Auger electron depth profi1ing spectroscopy, respectively. Finally, our newly proposed composite silicides had a stable resistance up to $1100^{\circ}C$ and maintained it below $20{\Omega}/Sg$., while the conventional NiSi was limited to $700^{\circ}C$. All our results imply that the composite silicide made from NiCo alloy films may be a possible candidate for 65 nm-CMOS devices.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.1 s.232
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• pp.71-79
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• 2005

For the non-premixed interacting jet flames, it has been reported that if eight small nozzles are arranged along the circle of $40{\sim}72$ times the diameter of single jet, the flames are not extinguished even in 200m/s. In this research, experiments were extended to the partially premixed cases to reduce both flame temperature and NOx emission. Nine nozzles were used- eight was evenly located along the perimeter of the imaginary circle and one at the geometric centre. The space between nozzles, S, the equivalence ratio, ${\phi}$, the exit velocity and the role of the jet from the centre nozzle were considered. Normally, flame was lifted and flame base was located inside the imaginary circle made by the nozzle. As nozzles went away from each other, blowout velocity increased and then decreased. The maximum blowout velocity diminished with the addition of air to the fuel stream. When the fuel and/or oxidizer were not fed through the centre nozzle, the maximum blowout velocity obtained by varying S and ${\phi}$ was around 160m/s. Optimum nozzle separation distance at which peak blowout velocity obtained also decreased with ${\phi}$ decrease. Flame base became leaner as approaching to the blowout. It seemed that lots of air was supplied to the flame stabilizing region by the entrainment and partially premixing. To approve this idea and to enhance the blowout velocity, fuel was supplied to the centre region. With the small amount of fuel through the centre nozzle, partially premixed flame could be sustained till sonic velocities. It seemed that the stabilizing mechanism in partially premixed interacting flame was different from that of non-premixed case because one was stabilized by the fuel supply through the centre nozzle but the other destabilized.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.630-630
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• 2013

Recently, atomically smooth hexagonal boron nitride(h-BN) known as a white graphene has drawn great attention since the discovery of graphene. h-BN is a III-V compound and has a honeycomb structure very similar to graphene with smaller lattice mismatch. Because of strong covalent sp2bonds like graphene, h-BN provides a high thermal conductivity and mechanical strength as well as chemical stability of h-BN superior to graphene. While graphene has a high electrical conductivity, h-BN has a highly dielectric property as an insulator with optical band gap up to 6eV. Similar to the graphene, h-BN can be applied to a variety of field, such as gate dielectric layers/substrate, ultraviolet emitter, transparent membrane, and protective coatings. However, up until recently, obtaining and controlling good quality monolayer h-BN layers have been too difficult and challenging. In this work, we investigate the controlled synthesis of h-BN layers according to the growth condition, time, temperature, and gas partial pressure. h-BN is obtained by using chemical vapor deposition on Cu foil with ammonia borane (BH3NH3) as a source for h-BN. Scanning Transmission Electron Microscopy (STEM, JEOL-JEM-ARM200F) is used for imaging and structural analysis of h-BN layer. Sample's surface morphology is characterized by Field emission scanning electron microscopy (SEM, JEOL JSM-7100F). h-BN is analyzed by Raman spectroscopy (HORIBA, ARAMIS) and its topographic variations by Atomic force microscopy (AFM, Park Systems XE-100).

• Atmosphere
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• v.20 no.2
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• pp.161-172
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• 2010

In an effort to investigate the characteristics of synoptic meteorological conditions in association with long-range transport of haze phenomena occurred over Korea, we statistically classified characteristics of haze events into two types of haze: stagnant case and long-range transport case, based on the synoptic meteorological parameters, and analyze comparatively the characteristics of synoptic meteorological conditions for each case. The results showed that the occurrence frequency of stagnant case accounts for 64.5%, showing superiority of stagnant haze cases over the long-range transport case which occupies only 35.5% among total 67 cases for the period from 2000 to 2007. This result indicates that haze phenomena occurred over Korea has influenced by not only the emission in Korea by itself but long range transport effects originating from China inland. The synoptic condition on 850hPa level showed that, when stagnant case occurred, Korean peninsula was located under the effects of negative vorticity with the significantly weak wind speed and stable atmospheric condition. In contrast, long-range transport case shows positive vorticity and relatively strong wind speed over 850hPa level, especially with the location of high pressure system over the area of southwestern China. This location of high pressure system implies to induce the westerlies or northwesteries consistently due to its pressure gradient by itself. Also other comparative studies haze days (vs.) Asian dust days are carried out, and we found out that the patterns of long-range transport of haze phenomena in Korea shows similar to Asian dust case but the static stability condition indicates more stabilized atmospheric condition than dust phenomena.

• Journal of Adhesion and Interface
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• v.20 no.4
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• pp.140-145
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• 2019

In view of environmental considerations, the control of carbon dioxide (CO₂) and volatile organic compounds (VOCs) is one of important issues in the film and coating industries. Therefore, UV-curable system has been developed due to minimize emissions of VOCs and reduce CO₂ emission due to low energy consumption from fast curing. Also, biodegradable polymers economically are attractive because of environmental and economic concerns associated with huge waste plastics. In this study, UV-curable polyurethane acrylates with different compositions of biodegradable polylactide (PLA) diol and poly(ethylene glycol) as diols were synthesized and curing reaction of their end-capped acrylates was performed by UV exposure. Tensile strength, elongation, and Tg of the UV-cured polyurethane acrylates increased with PLA diol content in the diol while their hydrophilicity and thermal stability increased with the PEG content. These results indicated a property of UV-cured polyurethane acrylates could be controlled by environment-friendly diols.