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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society for Atmospheric Environment
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Korean Society for Atmospheric Environment
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Volume & Issues
Volume 4, Issue 2 - Dec 1988
Volume 4, Issue 1 - May 1988
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Effects of Nitriles on Curing of Epoxy Resin
이재영 ; 심미자 ; 김상욱 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 1~1
Cure kinetics of diglycidyl ether of bisphenol A (DGEBA)/4,4'-methylene dianiline (MDA) systems with three nitriles were investigated by DSC analysis. Nitriles as reactive additives were malononitrile(MN), succinonitrile (SN) and glutaronitrile (GN). To estimate the kinetic parameters, Kissinger equation (dynamic run) and Fractional-life equation (isothermal run) were employed. The activation energy of DGEBA/MDA system is 11.11 kcal/mol and those of the DGEBA/MDA systems with MN, SN and GN are 11.38 kcal/mol, 11.48 kcal/mol and 11.32 kcal/mol, respectively. Due to the disturbance of nitrile compound to the reaction of amine and epoxide group, the activation energy is considered to increase while the cure rate is decreased.
A Study on the Contents of Soluble Sulfur and Heavy Metals in the Leaves of the Roadside Tree in Seoul Area
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 1~12
This study was carried out to measure the contents of soluble sulfur and heavy metals in the leaves of roadside tree at 34 sampling sites of Seoul area from the Sep. 1 to Sep. 30 during 1985 and 1986. The results were as follows; 1. Average contents of soluble sulfur at all sampling sites were; Plantanus orientalis 0.474%, Ginkgobioloba 0.562%, and Salix pseudolasiogyne 0.566%. 2. Correlation between sulfur dioxide concentration in the air and soluble sulfur in the leaves by area were; Green belt area R = 0.985, Residential area R = 0.856, Commercial area R = 0.668, Industrial area R = 0.886. Correlation by species were ; Platanus orientalis R = 0.817, Ginkgobiloba R = 0.771, Salix pseudo-lasiogyne R = 0.824. 3. Correlation between $SO_X$ concentration in the air and sulfur contents in the leaves showed positive significance. 4. Contents of soluble sulfur in the heavy traffic area were higher than that of light traffic area. 5. Heavy metal contents of 1986 were higher than that of 1985; Fe> Mn > Zn > Pb > Cu > Cd > Cr. 6. Lead contents in the leaves of 1986 were; Platanus orientalis 16, 701 ppm, Gingobiloba 21,729ppm, Salix Pseudo-lasiogyne 12.418 ppm.
Cure and Thermal Degradation Kinetics of DGEBA/MDA/PGE-AcAm/CTBN System by Kissinger Equation
이재영 ; 최형기 ; 심미자 ; 김상욱 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 7~7
The cure and thermal degradation kinetics of diglycidyl ether of bisphenol A (DGEBA)/4,4'-methylene dianiline (MDA)/phenyl glycidyl ether. (PGE)-acetamide (AcAm)/carboxyl terminated butadiene acrylonitrile copolymer (CTBN) system were studied by Kissinger equation. The activation energy of the cure reaction is 11.15 kcal/mol and the pre-exponential factor is
. Reaction orders are varied from 1.42 to 1.68 depending on cure temperatures. The activation energy of the thermal degradation reaction is 34.89 kcal/mol and the pre-exponential factor is
. The reaction orders were ranged from 4.83 to 5.85 according to the decomposition temperatures. The theoretical and experimental kinetics are well fitted, and it implies that Kissinger equation is applicable for studying the cure and thermal degradation kinetics.
A Study on the Synthesis of C₂-Hydrocarbons Using Methane Activation
김학수 ; 오세중 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 12~12
Oxidative coupling of methane was carried out by the combination of plasma and catalytic reactions. The plasma conditions were in the range of 100-300W discharge power, 10-100 SCCM total flow rate and 2-20 torr pressure. The catalysts used were Ni/La₂O₃ and Cu-Zn/ γ-Alumina. The catalysts were prepared by washcoating method on honey-comb type ceramic substrates. The preliminary test results showed that the plasma activation of methane was strongly affected by the discharge power and feed flow rate. The plasma/catalytic reactions improved the conversion of methane and C₂-yields as compared with the plasma reaction in the absence of catalysts, and Ni/La₂O₃ catalyst showed higher methane activity than that of Cu-Zn/ γ -Alumina catalyst. The optimum O₂/CH₄ ratio to maximize C₂-yields was studied.
Interactions between Hydrodesulfurization of Thiophene and Hydrodenitrogenation of Pyridine and the Kinetic Analysis
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 13~22
Interactions between hydrodesulfurization of thiophene and hydrodenitrogenation of pyridine and the kinetic analysis were studied over $Ni-W/\gamma-Al_2O_3$ catalysts and this study was made at temperatures ranging from 473-673 K and at total pressures ranging from 10-25 $\times 10^5$ Pa. Hydrodesulfurization of thiophene was inhibited by presence of pyridine at all temperatures studied, and the rate of pyridine hydrodenitrogenation was slower than that of thiophene hydrodesulfurization in the operating conditions. Pyridine hydrodenitrogenation was also inhibited by the presence of thiophene at low temperatures but was enhanced by the thiophene at temperatures higher than 613K. Thiophene reaction rate was determined by multiple linear regression analysis using Langmuir-Hinshelwood-Hougen-Watson model and the result was given to be $r = kP_T^p_H/(1+K_Tp_T+K_Pp_P)^2$. At each temperature, reaction rate constants and absorption equilibrium equilibrium constants were determined and the activation energy was 12.98 kcal/gmol from Arrhenius plot.
Synthesis and Properties of Carboxyalkyl Chitosan Derivatives
김천호 ; 최규석 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 19~19
Novel carboxyalkyl chitosan derivatives were prepared by reacting chitosan with 4-chlorobutyric acid or 5-chlorovaleric acid. The carboxyalkylation process was affected by the reaction medium, the reaction temperature, and the presence of catalytic base. The highest degree of substitution for chitosan derivatives was obtained from the reaction at 50 ℃ in methanol medium without base. Prepared carboxyalkyl chitosan derivatives exhibited the decreased crystallinity, which was confirmed by X-ray diffraction and thermogravimetric analysis. As a consequence, the carboxyalkyl chitosan derivatives showed an improved solubility in various solvents. Antibacterial activities of chitosan and carboxyalkyl chitosan derivatives against E.coli (ATCC 14339) and S. aureus (ATCC 6538P) were investigated by the viable cell counting method, and the carboxyalkyl chitosan derivatives showed higher antibacterial activity than chitosan. They also exhibited the high activity against E. coli, which is comparable to the activity S. aureus.
The Exposure Level of Respirable Dust of Underground Coal Mines in Taebaek Area
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 23~32
The exposure level of respirable dust and silica for the coal workers of underground coal mines in Taebaek area was evaluated. Personal air samplers were attached to the coal workers-drillers, coal cutters, their helpers, haulers, and separators. Normality and lognormality of respirable dust and silica concentrations were tested by Kolmogorov-Smirnov one-sample test, differences of means of respirable dust and silica concentration were tested by group-t-test and paired t-test, and relation between respirable dust and silica concentration were tested by regression test.
Depolymerization Behavior for cis-Polyisoprene Rubber in Supercritical Tetrahydrofuran
이승범 ; 홍인권 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 26~26
The cis-polyisoprene rubber was depolymerized in supercritical tetrahydrofuran. The process was then characterized by the degree of degradation and the depolymerized products were identified by instrumental analysis such as GPC, FT-IR, and GC-MSD. As a result, cis-polyisoprene rubber was degraded to low molecular weight polymers in 3 hours, which have narrow molecular weight distribution, and above 10 organic compounds were produced. The products were different at operating conditions. In addition, the degradation of cis-polyisoprene rubber had small dependency upon the operating pressure, and was inhibited with concentration.
Effects of Humidity on the Morphology of Microporous Membranes
박현채 ; 홍재민 ; 하성용 ; 강용수 ; 안규홍 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 31~31
The effect of the water vapor absorption into the cast polymer solution before immersing into the water coagulation bath was systematically studied in the preparation of asymmetric membranes by the phase inversion process. It was observed that both the relative humidity (RH) of the contacting air and the contact time had a pronounced effect on the membrane morphology. The pore size in the top skin layer and the skin layer thickness of membranes increased with the increase in the relative humidity of the contacting air as well as the contact time. When a membrane was prepared by coagulating a poly (ether imide)/1-methyl-2-pyrrolidone solution in a water bath, the longer contact time with water vapor resulted in the larger pores in the top skin layer and also the thicker skin layer. But the membrane morphology was slightly affected by the variance in the RH. When poly (vinyl pyrrolidone) was added in the membrane casting solution, both the contact time and RH had significant effects on the membrane morphology. The morphological change was confirmed by measuring the pure water transport characteristics through the membranes.
Effects of Simulated Acid Rain on Chemical Properties of the Experimental Soil of pinus densiflora S. et Z. and Forsythia Koreana Nak. Seedlings
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 33~44
For the purpose of examining the effects of simulated acid rain on the chemical properties of the experimental soil in Pinus densiflora seedlings and Forsythia koreana rooted cuttings, the experimental design of randomized block arrangement with three replications was implemented in the experimental field of Yesan National Agricultural Junior College. One-year-old Pinus densiflora seedlings and Forsythia koreana cuttings were planted in the pots filled the mixed soils (nursery soil: forest soil of siliceous sandy loam = 1 : V/V)in the early spring of 1985. The regime of artificil acid rain, in terms of spray frequency per monthly and spray amount at single treatment per plot, was simulated on the basis of climatological data averaged from 30 years records. Simulated acid rain (pH 2.0, pH4.0, and pH 5.5 as control) containing sulfuric and nitric acid in the ratio of 3:2 (chemical equivalant basis) diluted ground water, were treated on the experimental plants under condition of cutting off the natural precipitation with vinyl tunnel, during the growing season (May 1 to August 31) in 1985. THe results obtained in this study were as follows; 1. Soil acidity was dropped, and exchangeable aluminum contents in the soil was dramatically increased in both species, with decreasing pH levels of acid rain. 2. Exchangeable potassium, clacium, magnesium contents, and base saturation degree of the soil were highly drcreased in two species as the pH levels of acid rain decreased. 3. In two species, sulfate concentrations in the soil were decreased of pH 4.0 treatment, and remarkably increased at pH 2.0 treatment of acid rain in comparison with control. 4. Total nitrogen and available phosphate contents of the soil were not affected by acid rain treatment in the both species, and Fe contents at pH 2.0 treatment were highest among three acid rain treatments.
Molecular Weight Distribution of Polystyrene Solution with Solvent Density in Ultrasound Induced High Pressure Reactor
김형진 ; 홍인권 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 39~39
Molecular weight distribution of polystyrene fraction became narrow with the increase of solvent density in ultrasound induced high pressure reactor. The ultrasound induced high pressure reactor was filled with 0.5 w/v% polystyrene parent polymer and tetrahydrofuran, and then it was pressurized from 500 psi to 4000 psi at the intervals of 500 psi by high pressure liquid pump at the rate of 20 mL/min. And ultrasound was irradiated for 10 minutes at each pressure, and the extracts were analyzed by GPC. The molecular weight distribution of the extracts was characterized by the distribution function. The average molecular weight and polydispersity of polystyrene fraction were decreased with pressure, it was able to fractionate parent polymer and regulate polydispersity by pressure in ultrasound induced high pressure reactor.
Development of a Coarse Spherulite in Poly(vinylidene fluoride)/Poly(methyl methacrylate) Blends
이창형 ; 김준형 ; 이용무 ; 최형기 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 44~44
The spherulite formation in poly(vinyliden fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) blend was investigated by time-resolved light scattering under Hv (cross-polarized) optical alignment using (CCD) camera system. The final morphology was observed by atomic force microscopy (AFM) images and optical microscope (OM). The coarse spherulite was observed at high temperature (162 ℃) by OM, whereas the compact spherulite was appeared at low temperature (148 ℃ ). In the compact spherulite, the spherulite radius linearly increased with time. The order parameter defined by the sharpness of Hv scattering profile monotonously decreased with crystallization. In the coarse spherulite, the spherulite linearly grew, stopped growth for a while, and then restarted i.e., a pause in growth was observed. It was ascribed to the rejection of the noncrystallizable component (PMMA) at spherulite growth front. The order parameter initially increased, attained a maximum, and then decreased. Time at maximum point was consistent with onset time of a pause in the spherulite growth. Thus, a maximum in order parameter may be ascribed to the rejected PMMA at the spherulite growth front. A supplemental evidence for these results was provided by the morphology observation of the AFM
A Study of Energy and Spatial Structure -The Case of Rural-urban Regional Settlement-
金貴坤 ; 金命振 ; 成炫贊 ; 李鎬振 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 45~57
This is a close relationship between energy consumption and the way in which we develop and manage our regions. This study has estimated and compared energy requirements for the journey to work, resulting from alternative population and employment growth patterns in a rural-urban regional settlement of Korea. The broad scope of work was as follows: i) Select the study area ii) Formulate alternative growth patterns iii) Develop the Hansen and double-constrained gravity model iv) Application of Vogel's approximation method and the developed Hansen and gravity model to the case study area. v) Analyze the relationship between spatial structure, transport energy-requirements and environmental pollution. At issue here is the trade-off between air pollution averages and variations. Policies concentrating manufacturing industry and other regional facilities, for instance, may indeed reduce average pollution levels at the benefit of less-car miles, thus, reducing auto pollution, in the region, but increase local pollution peaks.
A Synthetic Study for Optically Active 3-Hydroxy-2-methylpropanoic Acid Derivatives via Chemical Asymmetric Decarboxylation
류상욱 ; 김영규 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 50~50
3-Hydroxy-2-methylpropanoic acid (β-hydroxyisobutyric acid, HIBA) and its derivatives are both academically and industrially important four-carbon chiral synthons that have one stereogenic center and two different functional groups at both ends of the molecule. Representative application examples are the synthesis of polypropionate natural products of biological and pharmaceutical importance and the preparation of captopril, a billion-dollar seller antihypertensive in 1993. Chemical asymmetric decarboxylation was selected for the preparation of enantiomerically pure HIBA and its derivatives as well as for the developed process to be industrially competent. The required intermediates, 2-hydroxymethyl-2-methylmalonic acid (4) and its mono-ethyl ester 12, were found out to be unstable under acidic or basic conditions, but could be prepared effectively by hydrogenolysis of their benzyl esters under neutral conditions. The overall yield was 86% for 4 in three steps and 77% for 12 in four steps. Although the asymmetric decarboxylation of 4 was not promising, it was successful with 12 to give optically active HIBA product. The chiral catalyst used here was the cinchona alkaloids that consist of two sets of families being pseudoenantiomeric to each other. The asymmetric induction was very low (2~5% ee) with a catalytic amount of the chiral amines but the sense of asymmetric induction was consistent in the same family. Improved enantioselectivities up to 18% ee were realized by use of excess chiral amines although the absolute ee values were not satisfactory. The enhanced ee values were resulted from replacing the proton of an achiral environment with one of the chiral amine salt. This process was flexible enough to produce either enantiomer by simply changing the chiral amine family.
Ion Exchange Characteristics of Platinum Group Metals from Nitric Acid Solution by Anion Exchangers
이성호 ; 김광락 ; 김유선 ; 백승우 ; 유재형 ; 정홍석 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 58~58
High-level wastes contain significant quantities of platinum group metals such as Pd(Ⅱ), Ru(Ⅲ) and Rh(Ⅲ). These metals are used for catalytic process, electronic and electrochemical industries, anti-corrosion alloys, dental applications, etc. The demand of noble metals continues to grow in a steady manner. There are many techniques such as solvent extraction, precipitation, ion exchange, and adsorption methods for separation and recovery of the platinum group metals. In this paper, batch experiments were carried out to investigate ion exchange characteristics of platinum group metals from nitric acid solution by anion exchangers such as IRN 78 and Dowex 1x8. The effects of ionic groups of anion exchangers, solution temperature, the concentration of nitric acid solution, and co-ions were investigated.
A Study of the Effects of Air Pollution on Health -Emphasizing on the Aspects of Respiratory Diseases in Medical Insurance Recipients-
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 58~70
The Application of Nickel(0) Catalyzed Homocoupling Reaction to the Synthesis of Novel 2,2'-Diphenyl-4,4'-dihydroxybiphenyl
배진영 ; Virgil Percec ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 64~64
Nickel(0)-catalyzed homocoupling of aryl mesylate of 4-protected-2-substituted hydroquinone was utilized in the key step of the novel synthesis of 2,2'-diphenyl-4,4'-dihydroxybiphenyl. The synthetic procedure reported in this paper is of important value since it represents an easy and direct access to a wide variety of 2,2'-disubstituted-4,4'-dihydroxybiphenyls employing readily available hydroquinone derivatives as starting materials.
Optimal Mobile-Phase Composition for the Resolution of Deoxyribonucleosides in RP-HPLC
소명섭 ; 박영광 ; 최대기 ; 노경호 ;
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 68~68
Five deoxyribonucleosides (dCyd, dUrd, dGuo, dThd, and dAdo) were separated by RP-HPLC under isocratic conditions. The volume percent of organic modifier was changed from 3.0 to 10.0 for methanol and acetonitrile, respectively. Potassium phosphate, sodium borate and TADP were used as buffer chemicals. The experimental results showed that for the separation of deoxyribonucleosides methanol was superior to acetonitrile as the organic modifier and the optimum condition of mobile phase was 5.0 vol. % of acetonitrile with 20 mM sodium borate.
A Study on the Health Effect of Air Pollution among the Express-way Tollgate Workers in Seoul
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 71~75
A Survey on the Status of Air Pollution around Toll Booth of Expressway -Around Seoul and Suwon Toll Booth-
Journal of Korean Society for Atmospheric Environment, volume 4, issue 1, 1988, Pages 79~83
To improve working environment for the toll workers who were working at Kyungbu expressway in outskirts of Seoul and Suwon, the status of air pollution surrounding toll booth were measured from March 28 through June 14, 1986. The results were as follows: 1. The amount of TSP (total suspended particle) surrounding toll booth was directly proportional to the traffic load. The ratio of traffic load at Seoul and Suwon toll was 3.2:1 and of TSP was 2.6:1. 2. The proportion of particle larger than 5$\mum$ was 24.8 $\sim$ 34.9% of TSP at Seoul toll and 19.2 $\sim$ 32.7% at Suwon. The proportion of particle less than 2$\mum$ was 38.7 $\sim$ 51.8% of TSP at Seoul toll and 34.8 $\sim$ 54.8% at Suwon. 3. The concentration of respirable particle les than 7$\mum$ measured by personal air sampler was higher in Seoul toll booth than that of Suwon and it seems to be influenced by the exhausion of diesel engine. Especially the concentration of respirable particle of reformed toll booth with air curtain was 20% lower than unreformed one. 4. Concentration of Pb among suspended particles around Seoul toll was 5 times higher than Pb of Suwon toll. So it is considered that there were other possible pollution source of Pb beyond heavy traffic in Seoul toll area. The amount of Pb inside toll booth was extremely small but the concentration of benzo(a)pyrene showed a trend of increase according to traffic stagnation. 5. The concentration of $SO_2$ arround toll showed no difference between weekday and weekend and also showed no relation with traffic load. But the concentration of $NO_2$ was affected by traffic load.