• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.83-88
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• 2003

The woodceramics are porous amorphous carbon and glassy carbon composite materials. Woodceramics attracted a lot of attention in recent years because they are environmentally friendly and because of their unique functional characteristics such as catalysis, moisture absorption, deodorization, purification, carrier for microbial activity, specific stiffness, corrosion and friction resistance, and their electromagnetic shielding capacity. In this paper, we made new products of clay-woodceramics to investigate the industrial analysis and ethylene gas adsorption for basic data of building- and packging- materials keeping fruit fresh for a long time. Clay-woodceramics were carbonized for 3 h of heating in a special furnace under a gas flow of nitrogen(15 ml/min.) from 3 layers-clay-woodparticleboard made from pallet waste wood, phenol- formaldehyde resin(hereafter PF, Non volatile content:52%, resin content 30%), and clay(10%, 20% and 30%). Carbonization temperature was 400℃, 600℃ and 800℃. Experimental results shows that the higher the carbonization temperature, the higher the fixed carbon and the lower the volatile contents. The higher the clay content, the more the ash content. The higher the carbonization temperature, the more the ethylene gas adsorption. Carbonization temperature of 800℃ gave the best reslts as same as that of white charcoal and activated carbon.(800℃-clay-woodceramic: 5.36 ppm, white charcoal: 5.66 ppm, activated carbon: 5.79 ppm) The clay contents did not make difference of ethylene gas adsoption.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.3
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• pp.132-138
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• 2003

We investigated the polarization retention characteristics of ferroelectric capacitors with $Pb(Zr,Ti)O_3$ (PZT) thin films which were fabricated by different deposition methods. In thermally-accelerated retention tests, PZT films which were prepared by a chemical solution deposition (CSD) method showed rapid decay of retained polarization charges as the thickness of the films decreased down to 100 nm, while the films which were grown by metal organic chemical vapor deposition (MOCVD) retained relatively large non-volatile charges at the corresponding thickness. We concluded that in the CSD-grown films, the thicker interfacial passive layer compared with the MOCVD-grown films had an unfavorable effect on retention behavior. We observed the existence of such interfacial layers by extrapolation of the total capacitance with thickness of the films and the capacitance of these layers was larger in MOCVD-grown films than in CSD-grown films. Due to incomplete compensation of surface polarization charges by the free charges in the metal electrodes, the interfacial field activated the space charges inside the interfacial layers and deposited them at the boundary between the ferroelectric layer and the interfacial layer. Such space charges built up an internal field inside the films, which interfered with domain wall motion, so that retention property at last became degraded. We observed less imprint which was a result of less internal field in MOCVD-grown films while large imprint was observed in CSD-grown films.

• Journal of the Korean Wood Science and Technology
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• v.36 no.2
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• pp.39-45
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• 2008

Formaldehyde and volatile organic compounds (VOCs) are emitted from wood-based panels that have been made using wood particles, wood fiber, wood chips, formaldehyde-based resins and so on. In this study, we examined formaldehyde and total VOCs (TVOC) emission behaviors for plywood overlaid with water-soluble phenolic resin impregnated linerboard (PL), and two kinds of surface materials (decorative veneer and pre-impregnated finishing foil) that were adhered onto the PL that named DPL and PPL. EVA (ethyl vinyl acetate) was used to overlay the decorative veneer and pre-impregnated finishing foil on the plywood with water-soluble phenolic resin impregnated linerboard by a hot press instrument. The debonding test and accelerated aging test were conducted to assess their mechanical properties. Formaldehyde and TVOC emission concentrations were measured using the FLEC method and a VOC Analyzer, respectively. The debonding test results of PL, DPL and PPL were 1.2, 1.5, and $0.5N/mm^2$, respectively. The surface appearance of the samples were not changed after the accelerated aging test. The PL and DPL exhibited reduced formaldehyde and TVOC emission levels, respectively. In the case of PPL, the VOC value was relatively higher than those of PL and DPL.

• Textile Coloration and Finishing
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• v.33 no.3
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• pp.153-160
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• 2021

In this study, composite materials were prepared by varying the content of glass fiber and bamboo fiber in PP/glass fiber/bamboo fiber. Experiments were conducted to confirm the mechanical properties(tensile, impact and burst strength) and volatile organic compound content of the bamboo fiber composite prepared under these conditions. An improvement in the main properties was observed at a fiber content of 30wt%. When the fiber fraction was increased above 30wt%, the mechanical properties tended to decrease due to the agglomeration of fibers at higher load fractions. In addition, the content of volatile organic compounds increased as the content of bamboo fibers increased, which is thought to be due to the volatile organic compounds generated during the manufacturing process of the composite material being present in the composite material without escaping from the pores of the bamboo fibers and volatilizing at a certain temperature. As a result of confirming the physical properties of the composite, it is considered that the optimal mixing condition is 30wt% of bamboo fiber for the composite produced by varying the amount of bamboo fiber composite. In the future, it is thought that follow-up experiments to confirm and improve the pre-treatment conditions for reducing the content of volatile organic compounds in the manufactured composite material are possible.

• Journal of the Korean Society for Railway
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• v.11 no.2
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• pp.182-187
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• 2008

The environmental significance of indoor air quality is gaining more attention. Especially, the contamination of indoor air by volatile organic chemicals (VOCs) has become a serious environmental concern. We investigated the VOCs emissions from some interior materials used in the conventional railway passenger cabin. The seat cover and the flooring of cabins were used as testing materials, and they were put in a clean environmental chamber. The temperature and relative humidity was kept at $25{\pm}1^{\circ}C$ and $50{\pm}5%$, respectively. It was found that these interior materials emitted significant amount of VOCs under constantly ventilated condition. The flooring emitted more halogenated VOCs than the seat cover, because it is made of PVC, which contains many chlorine atoms. However, the emission gradually decreased over time. Because the VOCs emission from interior materials may threaten the health of passengers in the cabin, interior materials emitting less VOCs should be used.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.83-90
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• 2007

This study aimed at examining the effect of rooms decorated by eco-friendly finishing materials in a newly built wooden house on the emission of indoor air pollutions. According to the results of examination, the levels of benzene, toluene, ethyl benzene and styrene in all the rooms were below criteria of indoor air quality of newly-constructed houses. The levels of natural volatile organic compounds (NVOC), anthropogenic volatile organic compounds (AVOC) and total volatile organic compounds (TVOC) in room R1-1 which had Hwangto wall covering on it, were relatively higher than in room phytoncide wallpaper covered R2-1. The room R2-2 where bamboo charcoal panel used for wall covering showed higher level of AVOC compared to the room R1-2. Living room R1-3 was found to contain less TVOC, compared to the other four rooms. In addition, the ratio of NVOC to TVOC in the living room was higher than in the other rooms. This seemed to be attributed to Cryptomeria Japonica the living room finished material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.67-68
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• 2006

Floating gate non-volatile memory devices with Au nano-particles embedded in SiON or $SiO_2$ dielectrics were fabricated by digital sputtering method. The size and the density of Au are 4nm and $2{\times}10^{-12}cm^{-2}$, respectively. The floating gate memory of MOSFET with 5nm tunnel oxide and 45nm control oxide have been fabricated. This devices revealed a memory effect which due to proGrainming and erasing works perform by a gate bias stress repeatedly.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.133-140
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• 2006

According to Tokyo protocol which suggests the prevention of global environmental pollution, Korean government establishes the standard of architectural materials emission consistency with best effort to decrease the environmental pollution. But many current architectural materials which are used for constructing and remodeling buildings are composed of a variety of chemicals. These include stimuli bad for the residents' health and safety and harmful discharged air polluting substances such as volatile organic compounds(TVOCs) and formaldehyde(HCHO) that in tern include a variety of carcinogen substances. These discharged substances are also researched into inducing 'sick building syndrome' which induces headache, dizziness, vomiting and concentration failure among residents. But the standard of architectural materials according to the Korean apartment provision is limited to emission factors: HCHO and TVOCs. So the aim of this study is to present a standard of functional material's emission consistency about TVOCs including glues and paints, and a certification grade for green building by instituting a materials standard for green building which has consideration for the residents' safety.

• Journal of Environmental Health Sciences
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• v.28 no.5
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• pp.86-92
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• 2002

This study was performed to assets the operating characteristics of food waste composting and co-composting (food waste + sewage sludge) at a compelling facility. The facility was being operated successfully without being affected by kind of composting feed materials. Partial anaerobic condition was detected during food waste composting and co-com-posting, but these two composting systems were proven to be operated successfully under aerobic condition from the monitoring results of $O_2$, volatile solids reduction rate, temperature, and other parameters. The conductivity and chloride concentrations of compost were gradually increased during two composting periods, but the conductivity and chloride concentrations of co-compelling indicated lower values than those of food waste composting at final point(40 m). As a result, co-composting was turned out to be more desirable than food waste composting, considering salt problem. High correlations ($R^2$= 0.9265 for food waste composting and $R^2$= 0.9685 for co-composting) between CEC and volatile organic matter were found. Quality of composts produced from two composting process satisfied Korean heavy metal standard.

• Journal of the Korean Society of Tobacco Science
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• v.35 no.1
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• pp.20-27
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• 2013

An Electronic Nose(E-Nose) and Gas Chromatography/Mass Spectroscopy (GC/MS) are meanwhile conventional technique to analyze volatile materials in many industries (e.g., food, medicine, environment) and have broad acceptance in the analysis of tobacco products. In this study, an experiment where tin oxide gas sensor array responses and GC/MS profiles are used to characterize the volatile compounds of different cigarettes at the same time is performed and the measurements of two instruments are compared for cigarette samples with a known chemical information. E-Nose and GC/MS were employed to differentiate and match flavored cigarettes with commercial tobacco flavoring agents (lavender, vanilla, peppermint, orange, star anise). For verifying reliability of two systems, the analyses were conducted in terms of amount of flavors in each cigarettes using partial least squares (PLS) and with the principal components analysis (PCA). Various chemical sensors and GC/MS data was reduced into two principal factors (PC1, PC2) for being distinguished with visualized regions. Both systems provided adequate results for odor characteristics of cigarettes in this study with each instrument having its own advantages and disadvantages.