• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.77-84
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• 2006

Modified polyesters (TTBA-10C, -20C, -30C) that contain phosphorus and chlorine were synthesized by the condensation polymerization of tetramethylene bis(orthophosphate), neohexanediol trichlorobenzoate, 1,4-butanediol and adipic acid, in which tetramethylene bis(orthophosphate) and neohexanediol trichlorobenzoate were prepared previously in our laboratory. In this study, two-component flame-retardant polyurethane coatings (TTBA-10C/HDI-trimer=TTHD-10C, TTBA-20C/ HDI-trimer= TTHD-20C, TTBA-30C/HDI-trimer= TTHD-30C) were obtained by curing at room temperature with the synthesized TTBAs and hexamethylene diisocyanate (HDI)-trimer as a curing agent. The obtained TTHDs were made into coating samples and used as test samples for various physical properties. The physical properties of the flame-retardant coatings containing chlorine and phosphorus groups were generally inferior to those containing only phosphorus group. Flame retardancy was tested by vertical and horizontal combustion method, and $45_{\circ}$ Meckel burner method. Since the retardancy of flame-retardant coatings containing chlorine and phosphorus groups was better than that containing only phosphorus group, it could be concluded that the retardancy by the synergism effect of chlorine and phosphorus groups exhibited.

• Resources Recycling
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• v.27 no.3
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• pp.93-99
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• 2018

Effective extraction of platinum group elements by dissolving waste platinum scrap from the display industry and solvent extraction, was studied. The extracted platinum solution was prepared as a precursor solution for diesel automotive exhaust gas purification catalyst and its catalytic activity was tested. The behavior of aqueous species of platinum was investigated through solution chemistry and based on the existence and behavior of these chemical species, the possibility of extraction and separation was established. By dissolving waste scrap by electrochemical method, the dissolution time of scrap was shortened and the extraction efficiency was increased. Through separation and removal of rhodium component, solvent extraction by TBP, and stripping by hydrochloric acid, Pt-Chloride-$H_2O$ solution was prepared. And then, an platinum amine complex solution through amination reaction with this solution as a raw material was prepared. The possibility of producing high-value platinum compounds from platinum group waste scrap was investigated by preparing platinum amine complex solution and then examining the catalytic activity with this amine precursor on the combustion reaction of carbon black.

• Economic and Environmental Geology
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• v.46 no.1
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• pp.63-69
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• 2013

This paper discusses important environmental issues that must be considered during shale gas development. Shale gas has been attracting many attention as the next key energy resource with its large abundance through easily accessible production fields, and its lower carbon dioxide & sulfur dioxide emission profile upon combustion when compared to the conventional oil and natural gas resources. Successful development of a shale gas field requires the use of hydraulic fracturing to recover hydrocarbon through the very tight shale formation, which has been frequently associated with environmental contamination issue of water, soil, and atmosphere. Therefore, environmental issues and their solution to minimize environmental impact should be considered for successful development of shale play in a future.

• Economic and Environmental Geology
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• v.22 no.2
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• pp.129-139
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• 1989

The anthracite coalfields of Korea are confined to the areas where sedimentary rocks of Permian and Jurassic are preserved. The Chungnam coalfield lies in the sedimentary rocks of Jurassic which belongs to the Daedong Supergroup (the Nampo group). For the property analysis of each coal seam interbeded in Daedong Supergroup, Seongju area is chosen and twelve coalseams are taken. Many standard tests have been established for optical analysis (maceral analysis, coalification degree measurement), chemical analysis (proximate, ultimate analysis) and physical analysis (ignition temperature, ash fusion temperature, hardgrove grindability index and X-ray diffraction). The Jurassic anthracite mainly consist of vitrinite and macrinite and the range of the reflectance is $R_{max}$ 5.0-6.5 which means metaanthracite rank. By the chemical composition analysis, it shows low H/C and high O/C value compare with international average value. By the physical analysis, it has very high ignition temperature ($531-584^{\circ}C$) and ash fusion temperature ($1510-1700^{\circ}C$) and very low combustion velocity (0.2-1.9 mg/min). The very wide range of the hardgrove grindability index (46-132) means that the grindability controlled mainly by the structural conditions of coal bearing strata.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.105.1-105.1
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• 2010

Korea Electric Power Research Institute (KEPRI) has developed a compact coal-gasification system to accumulate our experiment skills. The combustion furnace for residual oil was modified as a small size coal gasifier. Recently, coal feeding system was also upgraded to control coal feed rate more accurately. Our research group has conducted several experiments to find out the effect of $O_2$/coal ratio on the cold gas efficiency. Furthermore, the effect of $N_2$/coal ratio on the transport characteristics was also studied. According to the calculation of heat and mass balance, the cold gas efficiency was estimated to the maximum at $O_2$/coal ratio of around 0.73. But small size gasifier such as ours required higher value of $O_2$/coal ratio than that of the theoretical estimation. On the optimal $N_2$/coal ratio, we noticed that the coal feed rate was intimately related with the transporting gas pressure and the pipe diameter.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.63-74
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• 1999

When a fuel was injected with opening the intake valve of a port fuel injection engine, the spray atomization and flow characteristics in the intake port have a strong influence on the mixture formation of a combustion chamber. Thus , this study was to clarify the spray flow characteristics of the air-assist gasoline spray with fine dropkets across the suction air stream in model intake port. For the simulated opening intake valve in port, suction air stream was varied to 10m/s ∼30m/s. And fuel pressur ewas fixed to 300kPa, but air assist pressure was varied to 0∼25kPa for a vairable spray conditions. Spray flow trajectory was investigated by means of laser sheet visualization and the measurements of droplet sizes and velocities were made by PDPA system. Measured droplets within the spray flow field were subdivided into five size groups and then, the flow characteristics of droplet size groups were investigated to the spray across a suction air stream.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.47-53
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• 2004

Emulsion polymerization ws carried out using Alkyl methacrylate(RMA) like MMA, EMA, BMA and Styrene Monomer(SM) for core-shell latex preparation. It was synthesized at $80^{\circ}C$ in the presence of anionic surfactant SLS(Sodium Lauryl Sulfate). FT-IR and DSC analysis are used to confirm the synthesized core-shell emulsion latexes. Moreover DSC and TGA were used to investigate the thermal characterisitcs of them. The differences of the decomposition rate and the activation energy from TGA and DSC analysis are not so big. It considers that the pendent group is not affect of the thermal characteristics and stability on core-shell latexes, which is synthesized with RMA and Styrene. For investigating combustion products, LC50 values were calculated by FED(Fractional Effective Dose)from the Pyrolyzer-Mass sepctrometer.

• Journal of the Korean Ceramic Society
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• v.45 no.2
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• pp.112-118
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• 2008

To prepare the high-capacity cathode material with improved electrochemical performances, nanoparticles of $C0_3(PO_4)_2$ were coated on the powder surface of $Li[Co_{0.1}Ni_{0.15}Li_{0.2}Mn_{0.55}]O_2$, which was already synthesized by simple combustion method. The coated powders after the heat treatment at >$700^{\circ}C$ surely showed well-structured crystalline property with nanoscale surface coating layer, which was consisted of $LiCOPO_4$ phase formed from the reaction bwtween $CO_3(PO_4)_2$ and lithium impurities. In addition, cycle performance was particularly improved by the $CO_3(PO_4)_2$-coating for the cathode material for lithium rechargeable batteries.

• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.551-557
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• 2001

La$_{0.7}$Ca$_{0.3}$MnO$_3$분말을 용액연소법으로 제조하였으며 분말 특성과 CMR에 응용하기 위해 박막의 전기적, 자기적 특성을 조사하였다. 조성과 구조 특성을 XRD와 SEM으로부터 조사하였으며 분말의 하소온도를 TG 분석으로부터 결정하였다. 또한 소결성은 dilatometer에 의해 조사되었으며 분말 특성은 BET에 의해 조사되었다. 소결성이 우수한 분말을 이용하여 스퍼터 타겟으로 제조하였으며 SiO$_2$/Si 기판 위에 스퍼터링한 후, 온도에 따른 four point probe 측정으로 막의 MR비를 측정하였다. VSM (Vibrating Sample Magnetometer)를 이용하여 증착된 막의 온도에 따른 자화율(Magnetization:M)을 측정하였다. 분말 특성으로는 평균입자 크기가 sub-micron 이하로 초미세하고 49.44$m^2$/g의 비표면적 값을 얻을 수 있었으며 고순도의 perovskite 구조를 갖는 La$_{0.7}$Ca$_{0.3}$MnO$_3$분말을 쉽게 얻을 수 있었다. 온도에 따른 저항값의 변화로부터 96K에서 최고의 MR값을 얻을 수 있었으며, 240K에서 강자성체로 전이되었다.로 전이되었다.

• Journal of Environmental Science International
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• v.11 no.5
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• pp.455-461
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• 2002

Polycyclic aromatic hydrocarbons(PAHs) are ubiquitous contaminants in coastal marine environment. PAHs enter estuarine and nearshore marine environment via several routes such as combustion of fossil fuels, domestic and industrial effluents and oil spills. In August of 1997, mussels(Mytilus edulis) were collected at 6 sites near Kori nuclear power plant in order to analyze the PAH content by HPLC with uv/vis detection. Unfortunately, I could not find any living oysters in which I firstly intended to measure the PAH content in the study area. NPTHL and ANCPL were the major dominant PAH compounds in mussels living in the intertidal zone of Kori, Korea, and DahA, BbF, BaP were the next dominant PAH group in mussels in the study area. The mean concentrations of 15 PAH in mussels ranged from 3.2 to 1,680 ppb(mean 105$\pm$60.5 ppb). Compared with other studies world over, the concentrations of carcinogenic PAHs were relatively low in mussels in the study area, even though total PAH content was rather high. According to N/P(Naphthalene/Phenanthrene) ratio(147) and the ratio of 2∼3 ring to 3∼5 ring PAHs(58∼90 %) in mussels in the study area, I expect that the major source of PAHs in this study area is rather fresh petroleum-derived. This study presents preliminary data for the PAH levels in mussels from the intertidal zone of Kori, and the data will hopefully be utilized for the assessment of oil pollution in the East Sea, Korea.