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李鍾學,鮮宇昌辰,金雨植 연세대학교 산업기술연구소 1977 논문집 Vol.7 No.1
The performance of packed bubble column was investigated in a 3 inches I.D. acryl column packed with spiral wires. The effect of temperature on a gas hold-up(??) was studied from 15℃ to 45℃ in air-distilled water system with superficial gas velocity variation, and the over-all height of transfer unit ((H.T.U.)??), volumetric liquid phase mass transfer coefficient (??) and over-all absorption efficiency (??) were studied from 25℃ to 55℃ in CO₂-air-distilled water system, holding other conditions constant. The resulte showed that the ?? had the maximum value at 35℃ in unvibrational air-distilled water system and 25℃ in vibrational acceleration system. And the value of ??, ?? and E? were increased with increasing temperature up to 45℃ and decreased with increasing temperature above this value in CO₂ absorption system. The effect of temperature on k?a and (H.T.U.)? was relatively high, and effect on ?? and ?? was slight.
조영복,선우창신,유의연 全南大學校 觸媒硏究所 2003 觸媒硏究 論文集 Vol.24 No.-
A study on the carbon deposition of nickel catalysts for carbon dioxide reforming by methane was performed. The experiments were carried out at atmospheric pressure using a fixed bed flow reactor. The nickel catalysts for the carbon dioxide reforming were compared concerning the influence of promoter on catalytic activity and carbon deposition. The coke deposition on the promoted nickel catalysts was remarkably diminished with the addition of promoters such as K, Mn and Sm. The activitie of the promoted nickel catalysts decreased in the order Ni-Li> Ni-Mg > Ni-Ca > Ni > Ni-K > Ni-Na> Ni-Cs. The carbon deposition of the promoted nickel nickel catalysts decreased in the order Ni-Mg> Ni-Li> Ni> Ni-Ne> Ni-K> Ni-Cs. In the Ni-K/α-Al_2O_3, its activity was maintained over 70 hours at 700℃ without deactivation.
강웅일,선우창신,서호준 전남대학교 촉매연구소 2001 觸媒硏究 論文集 Vol.22 No.-
The functionalization of low density polyethylene with MAH (maleic anhydride), DEF (diethyl fumarate), DBM (dibutyl maleate) and MMA (methyl methacrylate) as a polar functional monomer and DCPO (dicumyl peroxide), BPO (benzoyl peroxide) as radical initiator was investigated. The grafting was conducted under different operating conditions to investigate the effects of various factors, such as unsaturated molecules concentration, initiator concentration, reaction temperature, reaction time. Also in order to investigated degree of functionalization, the grafted polyethylene wax characterized by FT-IR. DSC and SEM. The results of FT-IR spectra showed the grafting polymers analyzed a C=O absorbance band. A melting temperature and heat of fusion were confirmed by DSC. The optimal grafting yield was obtained at an unsaturated molecules concentration, 5g, initiator concentration, 0.8g reaction temperature, 140℃, reaction time, 3h. The grafting yield of the unsaturated molecules was as follow using DCPO; MAH>DEF>DBM>MMA and the grafting yield of the unsaturated molecules was follow using BPO; MAH>DEF>DBM=MMA and DCPO was found to be an excellent initiator for a grafting reaction.
개시제를 이용한 폴리에틸렌 왁스상에 MAH그라프팅 반응
강웅일,선우창신,유의연 全南大學校 觸媒硏究所 1998 觸媒硏究 論文集 Vol.20 No.-
Polyethylene wax was grafted with maleic anhydride using DCPO, DTBP, BPO, AIBN as an initiators and xylene as a solvent, The effect of reaction parameters such as MAH and initiator concentration, reaction temperature on percent grafting were studied. The maximum MAH extent of grafting achieved was 4.5%. The occurrence of a grafting reaction was analyzed by FT-IR spectrum of the polymeric reaction product of strong carbonyl streching absorbtions at ?? band. The efficiency of the radical initiators in reaction of polyethylene was with maleic anhydride was in the following order : DCPO ≒ DTBP〉BPO, ≒ AIBN
정도성,김상채,선우창신,유의연 全南大學校 觸媒硏究所 2003 觸媒硏究 論文集 Vol.24 No.-
Thermogravimetric analysis and pyrolysis experiment were used as studying the effent of conversional level on the thermal degradation of HDPE. The wide conversional range in this work encompassed a change in the degradation mechanism. To accommodate this mechanism change, the data were treated as a pseudo first-order reaction. It was observed that the data conformed to a first-order fit at conversional range of 0.05∼0.98 with an activation energy of 376 kJ/mol. The lower activation energy occurring at lower conversion (0.01∼0.05) is attributed to scission of 'weak links' in macromolecles. The higher activation energy was similar to the carbon-carbon bond dissociation energy and is associated with random scission throughout backbone chain. The lower the conversional level, the more abundant the paraffinic hydrocarbon in product. To what extent this finding are influenced by limitation of terminate reaction of radicals.
THE EFFECT OF ALKALI PROMOTERS IN OXIDATIVE COUPLINE OF METHANE WITH Mn - OXIDE CATALYSTS
Kim, Sang Chai,Sunwoo, Chang Shin,Yu, Eui Yeon 한국화학공학회 1990 Korean Journal of Chemical Engineering Vol.7 No.4
The catalytic oxidative coupling of methane to ethylene and ethane with manganese oxide catalysts promoted with alkali metal and alkali metallic-chloride has been studied at atmospheric pressure in a fixed bed flow reactor. The main studies of reaction were carried out over maganese oxide catalysts promoted with sodium chloride and the structure and surface morphology of these catalysts was characterized by an X-ray diffraction and a scanning electron microscope. The powdered MnO₂ was changed into Mn₂O₃, and MnO₂ containing alkali metallic-chlorides was not changed to new ternary oxides but changed into Mn₃O₄ and/or Mn₂O₃ at higher calcination temperature(above 780℃). The optimum content of NaCl promoted was 10-20wt%, an in over 10wt%, the conversion and the selectivity were kept constant. The main factor on deactivation of catalysts was the loss of the promoter(NaCl). The addition of alkali metal salts to manganese oxide catalyst has enhanced C₂(C₂H₄+C₂H_6) selectivity due to neutralizing acid sites more than the electronic factor. It was confirmed that chlorine in alkali metallic-chloride has enhanced the formation of C₂H₄, resulting, in a good C₂-yield (up to 25.7%).
Kang, UngIl,Sunwoo, Chang-Shin,Park, Chan-Young,Yu, Eui-Yeon 전남대학교 촉매연구소 2000 觸媒硏究 論文集 Vol.21 No.-
In order to study the functional enhancement of waste olefin polymers needed for recycling them such as compatibility with other polymers and pigments, dyeing it with dyestuffs, and adhesion and cross-linking to other metals, polyamides, and glasses, etc., this work employs polyethylene wax as a sample waste olefin polymer. The wax then has been grafted with maleic anhydride in a four-neck flask reactor equipped with a nitrogen purger, a vapor condenser, and a temperature controlled heater. With different organic peroxides such as dicumyl peroxide, di-tert-butyl peroxide, and benzoyl peroxide the wax was grafted with maleic anhydride and its degree of grafting was compared with the result for azo-bis-isobutyl nitrile, a non-peroxide. With di-cumyl peroxide as an initiator, the carbonyl group intensities at both 1861 and 1784cm-1 in the FT infrared spectroscopy for the grafted products, have revealed that the absorbance was over fifty percent more than that of di-tert-butyl peroxide, the second best initiator. The initiator content, the weight ratio, and the reaction temperature were varied from 0.06 to 0.375 weight percents of the total reaction volume, from 1.8 to 7.2 of maleic anhydride to polyethylene wax, and from 120 to 150℃, respectively, for all the above reactions. The acid titration of the grated wax with potassium hydroxide to measure the rate of the grafting suggests that the rate has almost the same order of magnitude where the percentage of maleic anhydride weight per volume is higher than 4.5. The result is the minimal required amount of the grafting agent, the maleic anhydride.