• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.41-46
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• 2014

The property improvement of polycarbonate coated with a multilayer film composed of an inorganic $SiO_2$ film and a photocatalytic $TiO_2$ film was studied. The $SiO_2$ film as a binder had an excellent light transmission characteristic. After the treatment with atmospheric pressure plasma, the surface of $SiO_2$ film showed the hydrophilicity, which increased the film coating uniformity with a $TiO_2$-containing aqueous solution. When $TiO_2$ film was over 200 nm thick, the absorption effect of UV rays in the range of 180~400 nm suppressed the yellowing phenomena of polycarbonate substrate. The inorganic film improved the heat resistance of polycarbonate substrates. $TiO_2$ film in the outmost under the exposure of UV rays promotes the catalytic oxidation characteristics and yields the capability to the decomposition of organic contaminants, and also increases the self-cleaning properties due to the increase of hydrophilicity. Structural stability of the polycarbonate substrate coated with inorganic $TiO_2$ and $SiO_2$ film was shown. The role of $SiO_2$ film between $TiO_2$ and polycarbonate substrate suppressed the peeling of $TiO_2$ film by inhibiting the photocatalytic oxidation effect of $TiO_2$ film on the polycarbonate substrate.

• Fire Science and Engineering
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• v.23 no.6
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• pp.116-125
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• 2009

This study is progressed function ratio, it's trued taste by an experiment to present data for human work light weight aggregate development that use clink ash progressed liquid limit, small success limit, wear loss in quantity, sand equivalent, sieve cutting examination. 80 : 20's match of function rain examination is 1.4, and that use rubble Goljae as ckink ash lightweight aggregate's capacity ratio increases by 1.0 increase of function rain many. Also, examination multiplied delicate flavor gradually according to increase of the mixing rate, and absorption coefficient increased. This is judged by phenomenon that appear by special quality upper clink ash of polystyrene bid and porosity's increase between lightweight aggregate. It is case that use aggregate of wear loss in quantity is 13.5 in sand equivalent and a wear loss in quantity experiment and although case that mix 20% increases by 14.4, this phenomenon by weak tissue of lightweight aggergate be judge. When it's as a these experiment, the statue prevention floor of a street improvement specifications is prescribing so that satisfy by sand equivalent 20, CBR 10. This is showed result that this satisfies in quality standard all in match experiment ago that see.

• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.632-639
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• 2021

In this research, fluorine doping was performed to enhance the photocatalytic activities of WO₃ which were measured using methylene blue dye. WO_3-xF_x photocatalyts were prepared by a vaper phase fluorination during a sintering for preparing WO₃ photocatalysts from a WCl₆ precursor. The bandgap energy of WO₃ photocatalysts decreased from 2.95 eV to 2.54 eV, and the oxygen vacancies site increased by about 55% after fluorine doping. In addition, the initial degradation efficiency of methylene blue showed that the fluorine doped sample showed a 6-fold increase in photocatalytic activities from 10% to 60% compared to that of the untreated sample. It is believed that fluorine is doped to reduce the band gap of photocatalysts, enabling the catalytic activity with low energy, and that oxygen vacancies-generated surface defects increase the visible light absorption region of WO₃ photocatalysts, thereby increasing photocatalytic activity. In this study, it was confirmed that fluorine-doped WO_3-xF_x photocatalysts with an excellent photocatalytic activity can be manufactured easily using a one-step vaper phase fluorination that does not require a post-treatment process.

• Applied Chemistry for Engineering
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• v.32 no.3
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• pp.312-319
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• 2021

Photothermal therapy is a treatment that necrotizes selectively the abnormal cells, in particular cancer cells, which are more vulnerable to heat than normal cells, using the heat generated when irradiating light. In this study, we synthesized a reduced graphene oxide with carboxyl groups (CRGO)-gold nanorod (AuNR) nanocomposite for photothermal treatment. Graphene oxide (GO) was selectively reduced and exfoliated at high temperature to synthesize CRGO, and the length of AuNR was adjusted according to the amount of AgNO₃, to synthesize AuNR with a strong absorption peak at 880 nm, as an ideal photothermal agent. It was determined through FT-IR, thermogravimetric and fluorescence analyses that more carboxyl groups were conjugated with CRGO over RGO. In addition, CRGO exhibited excellent stability in aqueous solutions compared to RGO due to the presence of carboxylic acid. The CRGO-AuNR nanocomposites fabricated by electrostatic interaction have an average size of ~317 nm with a narrow size distribution. It was confirmed that under radiation with a near-infrared 880 nm laser which has an excellent tissue transmittance, the photothermal effect of CRGO-AuNR nanocomposites was greater than that of AuNR due to the synergistic effect of the two photothermal agents, CRGO and AuNR. Furthermore, the results of cancer cell toxicity by photothermal effect revealed that CRGO-AuNR nanocomposites showed superb cytotoxic properties. Therefore, the CRGO-AuNR nanocomposites are expected to be applied to the field of anticancer photothermal therapy based on their stable dispersibility and improved photothermal effect.

• Journal of Powder Materials
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• v.28 no.2
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• pp.143-149
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• 2021

In this study, (GaN)_1-x(ZnO)_x solid solution nanoparticles with a high zinc content are prepared by ultrasonic spray pyrolysis and subsequent nitridation. The structure and morphology of the samples are investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The characterization results show a phase transition from the Zn and Ga-based oxides (ZnO or ZnGa₂O₄) to a (GaN)_1-x(ZnO)_x solid solution under an NH3 atmosphere. The effect of the precursor solution concentration and nitridation temperature on the final products are systematically investigated to obtain (GaN)_1-x(ZnO)_x nanoparticles with a high Zn concentration. It is confirmed that the powder synthesized from the solution in which the ratio of Zn and Ga was set to 0.8:0.2, as the initial precursor composition was composed of about 0.8-mole fraction of Zn, similar to the initially set one, through nitriding treatment at 700℃. Besides, the synthesized nanoparticles exhibited the typical XRD pattern of (GaN)_1-x(ZnO)_x, and a strong absorption of visible light with a bandgap energy of approximately 2.78 eV, confirming their potential use as a hydrogen production photocatalyst.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.6
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• pp.121-132
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• 2021

Green facade has a significant impact on building's energy performance by controlling the absorption of solar radiation and improving outdoor thermal comfort through shading and evapotranspiration. In particular, since high-density building does not enough green space, green facade, and rooftop greening using artificial ground plants are highly utilized. However, the level of cooling effect according to plant traits and irrigation control is different. Therefore, in this study, the cooling effect analyzed for a total of 4 cases by controlling the irrigation condition based on hedera and spurge. Although hedera under sufficient water had the highest cooling effect(-2℃~-4℃), had the lowest cooling effect under non-irrigation(+1.1℃~+4.4℃). In addition, hedera under sufficient water had cooling effect than hedera under non-irrigation(-1℃~-8.1℃) and in the case of spurge, it had cooling effect(-0.3℃~-7.8℃) more than non-irrigation. As a result of measuring the amount of transpiration according to the light intensity (PAR) and carbon dioxide concentration conditions, transpiration of hedera was higher than the spurge (respectively 0.63204mmolm^-2s^-1, 0.674367mmolm^-2s^-1). The difference in the cooling effect of the green facade under irrigation condition was significant. But the potential cooling effect of green facade according to plants species was different. Therefore, in order to maximize and continuously provide the cooling effect of green facade in urban areas, it is necessary to consider the characteristics of plants and the control of water supply through the irrigation system.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.1
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• pp.1-16
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• 2023

A non-rare earth-based strontium-aluminate red light emitting phosphor was synthesized by a solid-state reaction method and the effect of synthesis temperature and Mn⁴⁺ activator concentration on the photoluminescence characteristics of the phosphor was studied. The synthesized SrAl₂O₄:Mn⁴⁺ phosphor showed broad band absorption characteristics in the near-ultraviolet and blue regions with peaks at wavelengths of near 330 and 460 nm, and a triple band deep red emission consisted of three peaks at near 644, 658, and 673 nm. The SrAl₂O₄:Mn⁴⁺ phosphor synthesized at a temperature 1600℃ and a Mn⁴⁺ activator concentration of 0.5 mol% showed the strongest PL emission intensity, and concentration quenching was observed at concentrations higher than 0.7 mol%. FE-SEM and DLS particle size distribution analysis showed that the synthesized SrAl₂O₄:Mn⁴⁺ phosphor had a particle size distribution of 2~6.4 ㎛ and an irregular spherical shape with an average particle size of ~4 ㎛.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.3
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• pp.125-132
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• 2023

In this study, we compared the performance of machine learning models for predicting Vapor Pressure Deficits (VPD) in greenhouses that affect pore function and photosynthesis as well as plant growth due to nutrient absorption of plants. For VPD prediction, the correlation between the environmental elements in and outside the greenhouse and the temporal elements of the time series data was confirmed, and how the highly correlated elements affect VPD was confirmed. Before analyzing the performance of the prediction model, the amount and interval of analysis time series data (1 day, 3 days, 7 days) and interval (20 minutes, 1 hour) were checked to adjust the amount and interval of data. Finally, four machine learning prediction models (XGB Regressor, LGBM Regressor, Random Forest Regressor, etc.) were applied to compare the prediction performance by model. As a result of the prediction of the model, when data of 1 day at 20 minute intervals were used, the highest prediction performance was 0.008 for MAE and 0.011 for RMSE in LGBM. In addition, it was confirmed that the factor that most influences VPD prediction after 20 minutes was VPD (VPD_y__71) from the past 20 minutes rather than environmental factors. Using the results of this study, it is possible to increase crop productivity through VPD prediction, condensation of greenhouses, and prevention of disease occurrence. In the future, it can be used not only in predicting environmental data of greenhouses, but also in various fields such as production prediction and smart farm control models.

• Analytical Science and Technology
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• v.21 no.3
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• pp.222-228
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• 2008

On living skin the chances of a successfully developing latent fingerprint are very limited. This is due to the fact that continual perspiration and rapid absorption diffuse into the lipophillic layer on skin. A study was conducted to investigate effectively developing method of latent fingerprints on human skin surfaces and pig skin likely corpse's skin. We used commercial fingerprint powder, black powders, black magnetic powder, fluorescence magnetic powder, Cyanoacrylate fuming (CA) and direct lifting methods (lifting paper, glasses and photo glossy paper). Developing of fresh fingerprints on living skin was achieved with S-powderblack, CA fuming and CA fuming following S-powder, fluorescence powder. The other powder tends to overwhelm the latent print and the background. But, latent fingerprint residue was disappeared with time after deposit on a living surface. In case of pig skin likely corpse's skin, latent fingerprint detection was achieved with CA fuming following S-powder and deposited print during 6 hr at $25^{\circ}C$, 40% relative moisture yielded excellent fingerprints with clear ridge details using 1 min CA fuming. And enhancement of fingerprint detection image using forensic light source was achieved.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.47-54
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• 1985

An investigation was made to find regional differences and seed characteristics of buckwheats collected from 36 areas in Chungnam province in 1984, and the results obtained are summarized as follows; 1. Grain types of the collected buckwheats were classified as winged, semi-winged and common types. All collections were on the average composed of 50.1 % of common grain types, 26.8 % of semi-winged type and 23.1 % of winged types, respectively. However, there was a great regional difference in components of each grain type among collections. 2. The mean 1000 grain weight was 24.9 gr. The regional differences in 1000 grain weight showed that a collection (collection no. 30) from Susan was 17.4 gr and a collection (collection. no. 16) from Suchon was 31.9 gr. There wasn't any significant relationship between grain types component and 1000 grain weight. 3. Germination of seeds was accelerated as temperature goes up from $5^{\circ}C$ to $30^{\circ}C$. However, interesting germination pattern was observed. That is, seeds from Suchon (collection no. 16), Hongsung (collection no. 23), Cheonweon(collection no. 35), and Yesan (collection no. 27) showed abrupt decrease of germination rate at the temperature of $15^{\circ}C$. The seeds collected from Suchon (collection no. 29), Dangjin (collection no. 32) and from Chungyang (collection no. 21) showed decrease of germination rate at $25^{\circ}C$. These seeds showed, however, the increase of germination percentage at temperature higher than $15^{\circ}C$ and $25^{\circ}C$, respectively. The germination rate for the most collections at $5^{\circ}C$ was less than 10%. However, seeds from Asan (collection no. 33) and Daeduk (collection no. 3) showed 20% and 30% of germination rate at $5^{\circ}C$, respectively. 4. Color of seed coat could be classified into two maj or colors, dark and dark brown. Based on the seed coat color and grain types, all the collections could be classified into the following six categories: winged-black, semi-winged-black, common-black, winged-dark brown, semi-winged dark brown and common-dark brown. The different light absorption rate was found within the UV light zone (190-390 nm) depending upon the two different major seed coat color.