• The Korean Journal of Ecology
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• v.20 no.4
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• pp.233-238
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• 1997

To evaluate allelopathic effect of volatile chemicals and phytohormones, seed germination and seedling growth test of Lactuca sativa have performed in laboratory experiments. Among used chemicals terpienen-4-ol was the most inhibitory to seed germination of lettuce. ABA and GA inhibited seed germination at $5{\times}10^{-6}M$ concentration but promoted germination at $2.5{\times}10^{-5}M$ and $5{\times}10^{-5}M$. ABA and GA alleviated volatile chemical-induced inhibition of seed germination and seedling elongation of lettuce.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1042-1044
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• 1996

The use of fuzzy theory in task of pattern recognition may be applicable gases and odours classification and recognition. This paper reports results obtained from fuzzy c-means algorithms to patterns generated by odour sensing system using an array of conducting polymer sensors, for volatile chemicals. For the volatile chemicals clustering problem, the three unsupervise fuzzy c-means algorithms were applied. From among the pattern clustering methods, the FCMAW algorithm, which updated the cluster centres more frequently, consistently outperformed. It has been confirmed as an outstanding clustering algorithm throughout experimental trials.

• Korean journal of applied entomology
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• v.33 no.1
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• pp.19-25
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• 1994

Electrophysiological recordings of antennal responses to common plant volatile chemicals in the rice brown planthopper, Niloparuota lugens (Homoptera: Delphasidae}, were examined. Volatile plant chemicals were generally credited with a major role In host plant location for food or egg laying by many insects feeding on plants as adults and/or as larvae. An mitial examination of extracellular responses has been conducted. Acton potentials recorded from the plaque organs were initially positive-going, biphaslc spikes and the background firing rate of the cells recorded ranged from 1 ~22 impulses/sec. A wide range of responses to changes in concentration of the test chemical was observed. The commonest response was a relatively small increase in exitation with increasing concentration beween 1 J.lg and 100).\g on the filter paper in syringe. Adtivity either peaked at 100 $\mug$ and remained virtually saturated at 1000 f19 or tended to decrease at the highest concentration.

• Elastomers and Composites
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• v.35 no.1
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• pp.12-18
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• 2000

With growing concerns of environment and due to strengthening the government regulations on volatile organic compounds(VOC) the coatings industries are developing new technologies to reduce the amount of VOC released from coatings. In this study. a water soluble curing agent of amino-epoxy adduct was synthesized and its structure was identified by FT-IR, GPC and TG/DTA. The mechanical properties of the new curing agent in combination of KER-828 and KER-500 were investigated respectively. As an experimental result, the drying time of KER-828 was faster than that of KER-500 but the adhesion and impact strength of KER-500 was better than that of KER-828.

• KSBB Journal
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• v.29 no.2
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• pp.118-123
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• 2014

It was confirmed that malodor connected with an air-conditioner in an automobile is caused by microbial volatile organic compounds (MVOCs) produced by microorganisms getting into an air-conditioner when it is operating. Chemicals such as hydrogen sulfide, dimethyl sulfide, nbutyric acid, n-valeric acid, iso-valeric acid, n-octanol and toluene were detected above the odor threshold inside the automobile. The characteristics of a funky odor in the air blown into the automobile were due to detected sulfur compounds (hydrogen sulfide and dimethyl sulfide). Dimethyl sulfide was produced by microorganisms such as Aspergillus versicolor, Methylobacterium aquaticum, Herbaspirillum sp. and Acidovorax sp. In addition, the characteristics of a sour odor in the air blown into the automobile were due to detected organic acids (n-butyric acid, n-valeric acid and iso-valeric acid). N-valeric acid and iso-valeric acid were generated from Aspergillus versicolor, while iso-valeric acid was produced by Methylobacterium aquaticum. In addition, the odor intensity of the air blown into the automobile was affected by the concentration of detected sulfur compounds and organic acids. On the other hand, it is estimated that chemicals such as hydrogen sulfide, n-octanol and n-butyric acid detected in the air blown into the automobile were produced by non-identified species of microorganisms.

• Fire Science and Engineering
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• v.28 no.5
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• pp.71-79
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• 2014

This study was performed to test the combustive properties of Medium Density Fibreboards (MDFs) treated with chemicals of the bis-(dimethylaminomethyl) phosphinic acid (DMDAP), N,N-dimethylethylenediaminomethyl-bis-phosphonic acid (DMDEDAP), piperazinomethyl-bis-phosphonic acid (PIPEABP), and methylpiperazinomethyl-bis-phosphonic acid (MPIPEABP). MDFs were painted in three times with 15 wt% solution of the bis-(dimethylaminomethyl) phosphinic acid and alkylenediaminoalkyl-bis-phosphonic acids at the room temperature, respectively. After drying MDF treated with chemicals, combustive properties and volatile organic compounds (VOCs) contents were examined by the cone calorimeter (ISO 5660-1), test for flame retardant (NEMA Notice No. 2012034), and gas chromatography (KS M ISO 11890-2), respectively. It was indicated that the MDFs treated with chemicals showed the longer time to combustion time (CT) = (442~492) s than that of virgin plate by reducing the burning rate except for CT treated with DMDAP. In adition, the MDFs treated with chemicals showed both of the higher char area (44.33~61.33) kg/kg and char length (10.33~11.67) cm than those of virgin plate. Especially, the MDFs treated with chemicals showed the higher mean volatile organic compounds (VOCs) (0.188~0.333) g/L than that of virgin plate within the prescribed limits. Thus, It is supposed that the combustion- retardation properties were improved by the partial due to the treated chemicals in the virgin MDF.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.1
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• pp.11-24
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• 2011

Working in a research laboratory means exposure to a wide range of hazardous substances. Several studies indicated that laboratory workers, especially working with chemicals, might have an increased risk of certain cancers. However, exposure assessment data in laboratory settings are scarce. This study was performed to examine several approaches for quantitatively assessing the exposure levels to volatile organic compounds (VOCs) among workers in chemistry laboratories. The list of 10 target VOCs, including ethanol, acetone, 2-propanol, dichlormethane, tetrahydrofuran, benzene, toluene, n-hexane, ethyl acetate, chloroform, was determined through self-administered questionnaire for six chemistry research laboratories in a university, a government-funded research institute, or private labs. From September to December 2008, 84 air samples were collected (15 area samples, 27 personal time weighted samples, 42 personal task-basis short-term samples). Real time monitors with photo ionization detector were placed during the sampling periods. In this study, benzene was observed exceeding the action levels, although all the results were below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV). From the air sampling results, we concluded that (1) chemicals emitted during experiments could directly affect to neighbor office areas (2) chemical exposures in research laboratories showed a wide range of concentrations depending on research activities (3) area samples tended to underestimate the exposures relative to personal samples. Still, further investigation, is necessary for developing exposure assessment strategies specific to laboratories with unique exposure profiles.

• Journal of Environmental Health Sciences
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• v.31 no.3
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• pp.207-214
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• 2005

Many Japanese today are suffering from health disorders related to their living environment, such as allergies and hypersensitivity to chemical substances. The Sick House/Building Syndrome has been a serious problem since 1996, due to low level exposure to hazardous chemicals such as formaldehyde and volatile organic compounds (VOCs) emitted in airtight houses. This paper aims to show current status of the syndrome in Japan and practical researches to promote prevention of, and improvement to indoor air pollution due to chemicals.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.143-167
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• 2005

Many Japanese today are suffering from health disorders related to their living environment, such as allergies and hypersensitivity to chemical substances. The Sick House/Building Syndrome has been a serious problem since 1996, due to low level exposure to hazardous chemicals such as formaldehyde and volatile organic compounds (VOCs) emitted in airtight houses. This paper aims to show current status of the syndrome in Japan and practical researches to promote prevention of, and improvement to indoor air pollution due to chemicals.

• Journal of Soil and Groundwater Environment
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• v.12 no.6
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• pp.60-69
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• 2007

Understanding the behavior of gas phase VOCs (volatile organic compounds) in unsaturated soils is of a great environmental importance for public health concerns. Moment analysis for the breakthrough curves (BTCs) during transport of chemicals in porous media was known to be a useful tool to evaluate the velocity, spreadness, and the skewness of the plume of the chemicals. In this study, the temporal moments of the BTCs of a group of VOCs were analyzed for the gaseous transport in an unsaturated soil. BTCs were measured using lab-scale column experiments for four different VOCs at the water saturation range of 0.04-0.46, and for eleven VOCs at a water saturation of 0.21. The central second and third moments of the VOCs were compared with the water saturation and the first moment. It was found that both central second and third moments increased with the first moment. The central third moment was, however, found to be more sensitive to the first moment.