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        검색결과 59

        21.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Formaldehyde and phenol used in the production of melamine-wares may be intended to come into foodstuffs. So this study investigated the migration of formaldehyde and phenol from 222 articles Articles were cups(14), bowls(75), plates(85), spoons(10), chopsticks(4), food trays(8), rice paddles(4), spatulas(9) and scoops(12). The food stimulants were 4% acetic acid, 20% ethanol, distilled water and n-heptane. Korea regulation (Standards and specifications for food utensils, containers and package) specifies migration limits for formaldehyde and phenol in food stimulants. Formaldehyde and phenol are restricted by 4 mg/L, 5 mg/L respectively. In all cases the migration of formaldehyde and phenol were below the limit set in Korea regulation. The level of formaldehyde and phenol migrated to food simulants were in the range of N.D~2.949 mg/L, N.D~0.078 mg/L respectively. These migration results of formaldehyde and phenol will provide a scientific basis for the safety management of melamine-wares.
        4,000원
        22.
        2013.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        An elementary school is an important public place for children and it is where they spend most of their days. Ten elementary schools of environmental pollutants were measured in the classroom, playground and school zones (June 19 ~ Nov 1, 2012). Dust measurements of some schools were more indoor air. Measurements of black carbon concentrations were higher overall school zones. Also, in the case of formaldehyde, benzene and some environmental standards were exceeded. In the case of outdoor pollutants not statistically significant, but in some cars and vans that were correlated with pollutants. Thus, strategies and actions are necessary that will protect the health of children in schools from environmental pollutants.
        4,800원
        23.
        2012.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study was performed to evaluate the type and concentration of TVOC and formaldehyde emitted from asbestos stabilizers, because the stabilizers can be applied on the surface of asbestos contained building materials(ACBM). The emission test of three organic and synthetic resins(OSBS) and five inorganic based stabilizers(IBS) were tested for 7 days. The amount of emission and concentrations of TVOC were measured using GC/FID and GC/MS. In case of formaldehyde, quantitative analysis was carried out using HPLC. The average concentrations of TVOC and formaldehyde of 8 stabilizers were 1.173 mg/m2․h and 0.007 mg/m2․h, respectively. The maximum TVOC concentration among five OSBS was 5.698 mg/m2․h and exceeded the TVOC emission standard(4.0 mg/m2․h) for general building materials. According to the this study results, the applied stabilizer can be role one of pollutant sources like paints, floor tile etc. The emission test has to be tested one of stabilizers efficiency to manage the indoor air quality of building.
        4,200원
        24.
        2012.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        According to a recent government study, development and distribution of functional building materials are increasing in Korea.
        In this study, we evaluated reduction performance of formaldehyde and toluene by sorptive building materials using small-scale chamber(20L) test method for 7 days.
        According to the results of this study, 18 building materials showed that the effects of formaldehyde reduction among the 23 building materials. And the number of the building materials with respect to its ability to reduce the concentration of toluene was relatively small.
        The mean sorption rate and total amount of sorption for formaldehyde were 36.8% and 1,525.4㎍/㎡, respectively. The sorption rate and total amount of sorption for formaldehyde were in the range 1.5∼78.4% and 87.5∼3,086.0㎍/㎡, respectively.
        And the mean sorption rate and total amount of sorption for toluene were 11.6% and 1,054.4㎍/㎡, respectively. The sorption rate and total amount of sorption of toluene were in the range 0.1∼62.4% and 29.6∼6,764.0㎍/㎡, respectively.
        In most cases, the performance of the building materials with respect to its ability to reduce the concentration of pollutants has steadily decreased within 7 days.
        4,200원
        25.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Herein, macroporous carbon foams were successfully prepared with phenol and formaldehyde as carbon precursors and an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF6), as a pore generator by employing a polymerization-induced phase separation method. During the polycondensation reaction of phenol and formaldehyde, BMIPF6 forms a clustered structure which in turn yields macropores upon carbonization. The morphology, pore structure, electrical conductivity of carbon foams were investigated in terms of the amount of the ionic liquid. The as-prepared macroporous carbon foams had around 100-150 μm-sized pores. More importantly, the electrical conductivity of the carbon foams was linearly improved by the addition of BMIPF6. To the best of the author's knowledge, this is the first result reporting the possibility of the use of an ionic liquid to prepare porous carbon materials.
        4,000원
        26.
        2012.06 구독 인증기관 무료, 개인회원 유료
        As a part of abating formaldehyde emission of urea-formaldehyde resin, this study was conducted to investigate the rmalcure kinetics of both neat and modified urea-formaldehyde resins using differential scanning calorimetry. Neat urea-formaldehyde resins with three different formaldehyde/urea mol ratios (1.4, 1.2 and 1.0) were modified by adding three different additives (sodium bisulfite, sodium hydrosulfite and acrylamide) at two different levels (1 and 3wt%). An isoconversional method at four different heating rates was employed to characterize thermal cure kinetics of these urea-formaldehyde resins to obtain activation energy () dependent on the degree of conversion (). The values of neat urea-formaldehyde resins (formaldehyde/urea = 1.4 and 1.2) consistently changed as the increased. Neat and modified urea-formaldehyde resins of these two F/U mol ratios did show a decrease of the at the final stage of the conversion while the of neat urea-formaldehyde resin (formaldehyde/urea = 1.0) increased as the increased, indicating the presence of incomplete cure. However, the change of the values of all urea-formaldehyde resins was consistent to that of the Ea values. The isoconversional method indicated that thermal cure kinetics of neat and modified urea-formaldehyde resins showed a strong dependence on the resin viscosity as well as diffusion control reaction at the final stage of the conversion.
        4,000원
        27.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Our objective in this study is to assess the safety of docosahexaenoic acid (DHA) fortified milk of dairy cows fed feeds containing protected fish oil treated with formaldehyde by analyzing formaldehyde concentration in commercial milk and DHA fortified milk of dairy cows fed formaldehyde treated feed. There are 3 milk samples in this study: Commercial milk (CM), DHA fortified milk for Kid (DHA-K) and DHA fortified milk for Baby (DHA-B). We confirm the fresh quality of these three samples by physicochemical tests. In fat content result, three groups are significantly different at the p < 0.05 by Duncan's multiple range test, but fat content of group DHA-K is about half the level of the other two groups. Protein content of group DHA-K is 1% higher than other two groups. According to the analysis result of DHA content of DHA fortified milk, DHA content of DHA-B is two-fold higher than DHA-K. Similar pattern was seen in the intake based on age. According to HPLC analysis result of formaldehyde concentration in milk, commercial milk and DHA fortified milk are between 0.013 ppm and 0.057 ppm which is formaldehyde standard level in fresh milk settled in WHO (World Health Organization). Three groups have no significantly differences at the p < 0.05 by Duncan’s multiple range test. For this reason, it can be concluded that there is no transition of formaldehyde from dairy cows fed formaldehyde treated feeds to its produced milk. Safety about formaldehyde of DHA fortified milk of dairy cows fed formaldehyde treated feeds is considered similar to commercial milk.
        4,000원
        28.
        2011.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        A bake-out process using auto switchgear was carried out to evaluate the reduction effect of the concentration of volatile organic compounds (VOCs) and formaldehyde in newly-built apartments for seven days. The reduction rate of VOCs was observed as followings: 19%, 38%, 89%, 90%, and 96% for benzene, toluene, ethylbenzene, xylene, and styrene, respectively, which satisfies at the indoor air quality standards of newly-built apartment houses in Korea. The reduction rate of formaldehyde was 75%. Those results proved that the bake-out process using auto switchgear was effective for reducing indoor air pollutants.
        4,000원
        29.
        2011.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study was to assess the lifetime cancer and non-cancer risk on exposure to volatile organic compounds (VOCs) and formaldehyde of worker and user at public facilities in Korea. We measured the concentrations of formaldehyde and VOCs in indoor air at 160 public buildings that 5 kinds of public facilities (30 hotel, 30 fitness center, 25 gosiwon, 30 reading-room and 45 video-room) all over the country. There were estimated the human exposure dose and risks with averages of the using-time and frequency for facility users and office workers, respectively. Carcinogens (benzene and formaldehyde) were estimated the lifetime excess cancer risks (ECRs). Non-carcinogens (toluene, ethylbenzene, xylene, and styrene) were estimated the hazard quotients (HQs). HQs of four non-carcinogens did not exceed 1.0 for all subjects in all facilities. Higher HQs of toluene were observed at the reading-room. The average ECRs of formaldehyde and benzene for facility worker and user were 1×10-4~1×10-6 level in all facilities. The estimated ECRs for reading-room were the highest and the fitness center and gosiwon were the next higher facilities. Because lifetime ECRs of carcinogens exceeded 1×10-4 for facility worker in the most facilities, risk management of formaldehyde and benzene in the facilities was necessary. IAQ guidelines should be determined strictly to prevent occurrence of disease caused by poor IAQ beforehand.
        4,500원
        30.
        2010.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        In this study, the QA/QC test for the combined application of DNPH cartridge – HPLC/UV method was investigated in the collection and analysis of formaldehyde in air using three types of DNPH cartridge samplers made by three independent manufacturers. For these experiments, gaseous standards of formaldehyde (FA) were prepared at 7 concentration levels that fell in the range of 44.1~3400 nmol/mol. According to our analysis, the levels of cartridge blank (0.13 ~ 0.26 ng) are found to be fairly high to require routine check up for each experiment. The recovery patterns of FA were highly comparable between different cartridge products, when standard gases are supplied in the concentration range up to 177 nmol/mol. All 3 types of DNPH cartridge exhibited highly similar recovery rates at concentrations below 1.7 ㎛ol/mol, while the maximum recovery was attained from the product B. The overall results of our study suggest that one should calibrate the samples in the optimal range of recovery with routine check up of blank values.
        4,300원
        31.
        2010.02 구독 인증기관 무료, 개인회원 유료
        The potassium permanganate was used for manganese oxide catalyst with various methods and various processes, which manganese oxide wasused for removal of formaldehyde in flow gas. Experiments indicate that these catalyst materials are difference from each other because of raw materials used and pH values in catalysts preparation when used for formaldehyde removal. And when catalyst was prepared by using potassium permanganate and GLU or PEAunder different pH values respectively, it could have good performance in formaldehyde oxidizing purification. In this thesis, when the ratio of potassium permanganate and GLU was 5:1 for catalyst preparation, and 5 mL of nitric acid was added, the formaldehyde elimination efficiency could be maintained at 100% longer than 600 minutes. And when the ratio of potassium permanganate and PEA was 10:1 for catalyst preparation, and 5 mL of nitric acid was added, the formaldehyde elimination efficiency could be maintained at 100% longer than 705 minutes.
        4,200원
        32.
        2009.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to assess the removal efficiency of formaldehyde using carbon nano colloid (CNC) which was produced by comparatively easy and cheap method. In this study, carbon nano colloid based on water was produced by an electro‐chemical method. The particles which have mostly a spherical shape whose diameter was, what is called,‘nano‐size’were produced. Non‐woven fabric filter, which is currently on the market as a medium filter, was used for the removal efficiency test. Known concentration (0.5 ppm) of formaldehyde standard gas was used as a pollutant. The overall results indicate that (1) nanosize carbon colloids which have a stable dispersibility of which diameter is approximately 10 nm or less, (2) filters treated with carbon nano colloids showed higher removal efficiency, 44.47 ㎍ of HCHO removed/g of carbon and 19.28 ㎍ of HCHO removed/g of carbon, compared to the control experiment using a normal carbon filter, 1.45 ㎍ of HCHO removed/g of carbon.
        4,000원
        33.
        2009.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Studies on the indoor air quality inside newly producted vehicle have made mainly mention of the concentrations for indoor air pollutants or of subjective symptoms, such as irritated eyes and nose, headache and dizziness. That is, there has been no report about how poor indoor air quality inside newly producted vehicle affects vehicle drivers. We measured the indoor air pollutants inside newly producted vehicle and evaluated the neurobehavioral performance of drivers, using a computerized neurobehavioral test (color word vigilance), between a newly producted and a 11-year-old vehicle. Inside the newly producted vehicle, the formaldehyde concentration with closed window was 19.1㎍/m3. The concentration of VOCs with closed window was 3.9㎍/m3 for benzene, 316.7㎍/m3 for toluene, 20.5㎍/m3 for ethylbenzene, 47.7㎍/m3 for m,p-xylene, 15.1㎍/m3 for o-xylene, and 15.3㎍/m3 for styrene. The neurobehavioral performance of drivers inside newly producted vehicle with the computerized neurobehavioral test was 11.05% lower than that for those inside 11-year-old control vehicle. These results suggest that the poor indoor air quality inside newly producted vehicle affects the neurobehavioral performance of driver and a proper evaluation of the indoor air quality inside newly producted vehicle is required into the health effects of pollutants with objective tool, in addition to the level of pollution.
        4,300원
        34.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We proposed the new nano-carbon ball (NCB) materials for eliminating the total volatile organic compounds(TVOCs) from the felt which is built in the car. The concentrations of acetaldehyde and formaldehyde of the original felts were varied upon the different production lots. Acetaldehyde in the felt can be eliminated to target level(0.2μg) after introducing 0.5 wt% of NCB into the felt. Detector tube method for analyzing formaldehyde gas was more accurate than HPLC method. Formaldehyde can be eliminated to target level (64 ppb) after introducing 0.5 wt% of NCB into the felt. We also found that TVOC can be reduced to target level (0.32μg) after introducing 2.0 wt% of NCB. Upon introducing small amounts of NCB into the felt, it was possible that the level of formaldehyde, acetaldehyde and TVOC formed from the felts can be reduced to the target level. We also suggest the effective analyzing method of TVOCs.
        4,000원
        35.
        2008.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate airborne volatile organic compounds(VOCs), formaldehyde, respiratory particulate for concentration in primary schools. The concentrations of major indoor air pollutants(VOCs , benzene, toluene, ethylbenzene, xylene, styrene, formaldehyde, PM-10) were observed from November to December 2006. Sampling was undertaken at 81 primary schools. The sampling sites of air pollutants are classroom and hallway. VOCs with distribution of most of general environmental contamination material will be able to confirm that it shows the log-normal distribution which is similar exposure distribution. The exposure quality of VOCs and the place pollution level was indoor> hallway>outdoor, which whole is located in the metropolis and the industrial areas is higher than farm village area. It tried to observe the I/O ratio, it appeared highly from the interior of the material of most. The mean concentrations of formaldehyde, respiratory particulate were 22.07㎍/㎥, 88.06㎍/㎥ respectively. Indoor and outdoor ratios(I/O) of formaldehyde and respiratory particulate were 3.6 and 1.4, respectively. The concentration of respiratory particulate is 27.2% higher than guideline for school hygiene(100㎍/㎥). From the comparison in the construction year, the highest concentration of formaldehyde is showed under one year. However, as time passed by the concentrations of formaldehyde become lower.
        4,500원
        36.
        2007.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Novolac is widely used as the primary solid component of most photoresists in semiconductor and microelectronic devices. In this study, novolac resins were prepared by condensation of 35% formaldehyde with phenolic compounds such as m-/p-cresol, 2,5-dimethylphenol and bisphenol A in the presence of oxalic acid as catalyst. The average molecular weight (Mw) of these novolac resins has been varied on the changing of mixing ratio of m-/p-cresol/2,5-dimethylphenol/bisphenol A or formaldehyde/phenolic compound. Also, thermal properties of novolac were observed by TGA.
        4,000원
        37.
        2007.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Kevlar was chemically surface modified with resorcinol-formaldehyde(RF) prepolymer and VP rubber latex for application to high strength tirecords. RF prepolymer was easily obtained by polymerization at room temperature in the presence of a base catalyst. The mechanical and thermal properties of Kevlar were not significantly changed during surface treated under various conditions. The change of adhesion with rubber were investigated through H-test method. Maximum increase of adhesion force between rubber and Kevlar was obtained up to 40% than that of untreated one when the fiber was soaked in RFL dipping solution and thermally treated at 170℃ for 3 - 5min.
        4,000원
        38.
        2006.09 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The deodorization performances of ammonia, acetic acid and acetaldehyde were tested for each of all forty five air cleaners sold in the online shops and department stores. The removal performances of toluene and formaldehyde were also investigated and the results were compared to the deodorization performances for the air cleaners. Filter-type and complex type air cleaners which used activated carbon filters showed superior in odor removal performances to those of ionizer type and wet type air cleaners. Toluene and formaldehyde were readily removed for the most of filter-type and complex type air cleaners. Ionizer air cleaners had little removal ability for the toluene and formaldehyde.
        4,200원
        39.
        2006.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Methanol and formaldehyde were produced directly by the partial oxidation of methane over mixed oxide catalysts. The catalysts were composed of Mo and Bi with late-transition metals, such as Mn, Fe, and Co. The reaction was carried out at 450℃, 50 bar in a fixed-bed differential reactor. The prepared catalysts were characterized by O2-TPD and BET apparatus. Among the catalysts used, the catalyst composed of 1:1:2.5 molar ratio of Mo:Bi:Mn showed the best methane conversion and methanol selectivity. The change in ratio of methane to oxygen affected at the conversion and selectivity, and the most proper ratio was 10:1.5. Methane conversion, methanol and formaldehyde selectivities increased with the surface areas of the catalysts. From the O2-TPD result, it was found that the oxygen species responsible for this reaction might be the lattice oxygen species desorbed at high temperature around 800℃.
        4,000원
        40.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Methanol and formaldehyde were produced directly by the partial oxidation of methane. The catalysts used were mixed oxides of late-transition metals, such as Mn, Fe, Co, Ni and Cu. The reaction was carried out at 450℃, 50 bar in a fixed-bed differential reactor. The prepared catalysts were characterized by XRD, TPD and BET apparatus. Of the catalysts, A-Mn0.2-6, which contains 0.2 mole of Mn and calcined at 600℃, showed the best catalytic activity: 3.7% methane conversion, and 30 and 28% methanol and formaldehyde selectivities, respectively. The catalytic activity was changed with the content of Mn and the calcination temperature. Catalytic activity increased with the specific surface areas of the catalysts. With XRD, it was found that the structure of the catalysts are changed with calcination temperature. Through O2-TPD experiment, it was found that the catalysts showing good catalytic activity showed O2 desorption peak around 800℃.
        4,000원
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