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김헌수,박해천 조선대학교 생산기술연구소 2005 生産技術硏究 Vol.27 No.2
Lately, electronics industries manufacture electronic products in cooperation between mother companies producing finished goods and sub-contractors delivering parts to them. So, in electronics industries, not only are the manufacturing activities of mother companies important but also are the manufacturing activities of sub-contractors supplying various components to their customers important. With this environment, it is difficult to survive in the global competitions not only for the parts suppliers but also for the customers being supplied with parts by their part sub-contractors. But, it is getting specialized so the customers could not survive without their sub-contractors. So, the customers need to consider their suppliers as their extended production lines and introduce a comprehensive safety management support system to prevent industrial accidents by implementing systematic safely management support activities.
윤호상,진춘조,유광하,이상엽,이수인,정상만,김선두,이순제,이길도,전혜정 건국대학교 의과학연구소 2000 건국의과학학술지 Vol.10 No.-
Chronic eosinophilic pneumonia(CEP) is a rare disease of unknown etiology characterized by chronic infiltration of the lung with eosinophils. It presents with profound systemic symptoms comprising fever, night sweats, weight loss, dyspnea and blood eosinophilia with nonsegmental air-space consolidation confined to the outer third of the lung, the "photographic negative of pulmonary edema". Histopathologic features of chronic eosinophilic pneumonia are intraalveolar and interstitial infiltrations with eosinophils, histiocytes, giant cells, scattered lymphocytes and plasma cells. Glucocorticoid therapy cause prompt resolution of symptoms as well as disappearans of blood eosinophils, elevated serum Ig E levels and the roentgenographic lesions. Infrequent radiographic findings include nodular infiltrates, consolidations, cavitations, atelectasis and pleural effusions. Deaths from CEP although rare, have been reported, but the majorities of CEP have benign courses and do not need a therapy with ventilator. We report a case of chronic eosinophilic pneumonia, which had a sudden course associated with diffuse pneumonic consolidations on the both lung and bilateral pleural effusion.
Effect of Ni3Al Inelusion on Pore Structure in the Porous Anode for Molten Carbonate Fuel Cell
Chun, Hai Soo,Kim, Yun Sung,Choo, Hyun Suk,Shin, Min Cheol,Hong, Ming Zi,Lim, Jun Heok 한국화학공학회 2000 Korean Journal of Chemical Engineering Vol.17 No.5
Microstructural changes in pure Ni, Ni/(4-10 wt%)Ni₃Al and Ni/5 wt%Ni₃Al/5 wt%Cr anodes for molten carbonate fuel cell were investigated by sintering experiment. Submicron-sized Ni₃Al intermetallic particles were dispersed in nickel powders to improve mechanical strength by dispersion strengthening and to control both densification and pore structure of these anodes during sintering. The mechanical strengths of Ni/7 wt%Ni₃Al and Ni/5 wt%Ni₃Al/ 5 wt%Cr anodes were considerably higher than that of the pure Ni anode by strong bonding between small nickel grains. Pore volume in the anodes which included Ni₃Al was considerably high by impeding nickel grain growth, because the retarding force exerted by the Ni₃Al inclusion obstructed the nickel grain boundary movement. Pore structure in the anodes was maintained in a relatively stable open network in contrast with that in the pure Ni anode.
Enhancement of Mass Transferin the Fluidized Bed Electrode Reactors
Chun, Hai Soo,Hwang, Young Gi 한국화학공학회 1999 Korean Journal of Chemical Engineering Vol.16 No.6
With the view of developing the fluidized bed electrode system, mass transfer coefficient, overpotential distribution, and copper degradation have been observed in this investigation. Particles whose diameters were one of 327, 388, 510, 548, 750, and 960㎛ were fluidized by the 1,000ppm copper sulfate electrolyte. This study used two types of the experimental reactor. One had 5×5.5㎝ bed-dimension with various thickness in a rectangular side-by-side configuration; the other 3.2cm bed-diameter with various height in a cylindrical flow-through configuration. Mass transfer coefficient increased with increasing particle diameter, and the optimum fluidization was obtained at the condition of bed porosity near 0.65. For processing a large fluidized bed reactor, the expansion of bed height at a distance between electrodes was found to be more effective than the enlargement of bed thickness between electrodes. By replacing a three-dimensional current-feeder with a plane feeder, degradation and residual concentration of copper ion in a batch recycling mode could be achieved to be higher than 99% and less than 5㎎/L, respectively.
Pack Cementation 법으로 제조된 MCFC 용 합금 Anode 의 특성
전해수,박권필,임희천,정하철 한국화학공학회 1998 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.36 No.6
용융탄산염 연료전지(MCFC)용 anode 재질로써 촉매 성능면이나 가격면에서 가장 적합한 것은 Ni이나, 순수한 Ni만으로 제조된 anode는 고온에서 크립(creep)현상이 커서 이의 해결책이 강구되어져야만 한다. 본 연구에서는 이 크립 현상을 감소시키기 위한 한 방법으로 pack cementation 기법을 이용하여 다공성 Ni-anode소재에 Ni-Al, Ni-Cr, Ni-Al-Cr등의 합금 형태(금속간 화합물 또는 고용체)가 되도록 처리한 후 해당 재질들의 크립 특성을 검토하였다. 이때 팩(pack)성분은 증착시키려는 금속 분말과 활성제(NaCl, NH₄Cl), 그리고 비활성 충전물(Al₂O₃)로 구성되었고 온도는 550-900℃의 범위에서 0.5-5시간 동안 반응시켰다. 다공성 Ni 소재에 해당 금속의 증착량은 반응 시간의 제곱근에 비례하는 형태를 나타내었으며 증착량이 증가할수록 다공성 Ni소재 anode의 기공도는 선형으로 감소하였다. 순수한 Ni소재 anode에 비하여 합금 형태 anode는 크립 현상이 크게 감소함을 보였고 특히 Al과 Cr이 동시에 증착된 합금 전극의 수축률이 가장 낮은 1-2%의 값을 보였다. The pack cementation process of metal(Al, Cr) halide vapor on a porous pure Ni-anode substrate for molten carbonate fuel cell was studied to improve creep resistance of the anode substrate. The pack consists of metal powder(Al, Cr or Al-Cr mixture), activator(NaCl or NH₄Cl) and inert filler(Al₂O₃). The pack cementations on the nickel-anode substrate were carried out at 550-900 ℃ for 0.5-5.0 hours. It was found that various intermetallic compounds for Al(Ni₃Al, NiAl, or Ni₂Al₃) and some of solid solution between Ni and Cr were formed on the porous Ni-anode substrate and the deposition weight of metals depending on time was parabolic. The porosity of the alloy anodes(intermetallic or solid solution) decreases linearly with deposition content of metallic additives. The Ni-anodes deposited as Ni-Al intermetallic form and codeposited with Al and Cr showed good performance against creep and its pore structure did not change after pack cementation. The Ni-anode substrate, which Al and Cr were codeposited on, showed about 1 % creep strain under 650 ℃ and 100 psi after 100 hour.
망사 충전 고정층 반응기의 특성 : 농도 분포 Concentration Distribution
전해수,임종성,김봉현,박권필 한국화학공학회 1992 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.30 No.2
망사 충전물을 삽입한 촉매고정층 반응기에서 농도분포에 대하여 연구하였다. 에탄올 탈수 반응이 일어나는 활성알루미나 입자고정층 및 망사 충전물을 삽입한 고정층을 설치하여 유속분포가 다른 조건하에서 농도분포를 측정하였다. 기벽 인접 영역에서의 공극율의 불균일로 인해 유체유속분포와 농도분포가 불균일하지만 고정층에 망사 충전물을 삽입함으로 인해 농도분포를 균일하게 할 수 있었다. 공극율 및 망사 충전물의 삽입효과를 고려한 고정층 내 운동량 및 물질전달 지배방정식의 수치해로 구한 에탄올 출구농도는 에탄올 검류관으로 측정한 실험치와 비슷한 값을 보였다. The concentration distribution in a catalytic packed bed with packing was studied. The resistance to flow in the bed, packed with activated alumina particles to catalyze ethanol dehydration reaction, varied by inserting screen-packing and different size particle section. It was found that the velocity- and concentration-profiles were non-uniform due to the variation of void fraction near the wall. The effect of inserting the screen-packing in the bed enabled velocity- and concentration-profiles to be uniformly distributed over the bed. The governing equations for momentum- and mass-transport in the fixed bed and the fixed bed containing a screen-packing were numercasslly solved to demonstrate the effects of the void fraction and the screen-packing inserted in the bed. Effluent ethanol concentrations, measured by ethanol detector tube, were found to be varied with radial position in a manner consistent with the modeling equations.
전해수,이윤용,임종성,조정식,김재덕 한국화학공학회 1991 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.29 No.4
기상과 액상 모두를 계속해서 순환시키는 circulation type의 고압상평형장치를 이용하여, CO₂-C₂H_5OH-H₂O계에 대한 고압기액상평형실험을 313.2 K와 333.2 K에서 압력 (7.9 ㎫에서 18.5 ㎫까지)과 feed 에탄올농도(20 wt%에서 70 wt%까지 ; CO₂ free basis)를 변화시키면서 수행하였다. CO₂-C₂H_5OH-H₂O계의 고압상평형자료를 Adachi와 Sugie의 혼합규칙을 사용한 Patel-Teja식에 적용하여 상관시켜 본 결과 Wilson type의 혼합규칙, 그리고 Group Contribution Equation of State를 사용할 때보다 기액상평형을 잘 예측할 수 있었고, 본 실험자료와 만족할만한 상관결과를 얻을 수 있었지만, 분리계수나 분배계수의 거동에 대한 예측은 정확하게 표현하지 못하였다. High pressure vapor-liquid equilibria for CO₂-C₂H_5OH₂O system were measured at two temperatures of 313.2 K and 333.2 K using a circulation type of apparatus in which both vapor and liquid phase were continuously recirculated over a pressure range from 7.9 ㎫ to 18.5 ㎫. The ethanol concentration in feed varied from 20 wt% to 70 wt% (CO₂ free basis). The Patel-Teja Equation of State with Adachi-Sugie mixing rule predicted the experimental data better than the same equation of state with Wilson type mixing rule and Group Contribution Equation of State, but could not accurately represent the behavior of the separation factor and distribution coefficient.
전해수,강웅기 한국화학공학회 1981 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.19 No.3
황산(0.1M 및 1M) 산성의 황산구리전해액(0.032M Cu)으로 구리입자(0.5㎜)를 유동화시키는 직사각형-십자류(전해액-전류사이에) 유동층전극반응기내에서 층팽창율과 전류밀도를 변화하여 연속상 및 분산상전위를 각각 측정하고, 이로부터 연속상 및 분산상의 유효전기비전도도와 총괄유효전기비전도도를 산출하였다. 그 결과 연속상유효전기비전도도는 층다공율의 3.0승에 역비례하고, 분산상유효전기비전도도는 층다공율의 12.0승에 역비례하고, 총괄유효전기비전도도는 층다골율의 6.8승에 역비례하였다. Potential profiles of continuous electrolyte phase and dispersed particle phase were measured in a fluidized bed electrode reactor of rectangular geometry. The reactor with solid copper particles(0.5 mm in diameter) was used to deposit copper from acidified aqueous solutions. (0.1M and 1M H₂SO₄) containing 0.032M of copper. Effective specific electrical conductivities of individual phase could be calculated from the potential profiles. Rasults showed that the effective specific electrical conductivity of continuous electrolyte phase was inversely proportional to the 3.0 power of the bed porosity and proportional to the electrolyte specific electrical conductivity, the effective specific electrical conductivity of the dispersed particle phase was inversely proportional to the 12.0 power of the bed porosity, and the overall(or equivalent) electrical conductivity of the bed was inversely proportional to the 6.8 power of the bed porosity.
Poly(acrylonitrile)- L1계 폴리머 전해질의 전기화학적 성질
전해수,김형선,윤경석,조병원 한국화학공학회 1997 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.35 No.1
Polyacrylonitrile(PAN) 매트릭스에 LiClO₄, LiAsF_6, LiBF₄, LiPF_6 등의 리튬염과 ethylene carbonate(EC) propylene carbonate(PC)유기용매 등이 캡슬화된 폴리머 전해질의 전기화학적인 특성을 조사하였다. 모든 조성의 폴리머 전해질의 이온 전도도는 상온에서 10^(-3)-10^(-4)s/㎝범위를 나타냈다. 리튬 전극과 폴리머 전해질간의 시간에 따른 계면 저항은 EC/PC의 유기용매비가 75:25일 때 가장 안정한 것으로 나타났다. 이 용매비에서 LiPF_6 리튬염을 갖는 폴리머 전해질의 이온 전도도 및 계면 저항은 시간에 따라 안정한 값을 보였다. 이 전해질은 4.3V(vs. Li^+/Li)까지 전기화학적으로 안정하였고 따라서 리튬 폴리머 전지에 적용 가능한 것으로 나타났다. 폴리머 전해질들에서 리튬 이온의 확산계수는 4×10^(-7) ㎠/sec이며 교환 전류밀도는 시간에 따라 감소하는 것으로 나타났다. The electrochemical properties of polymer electrolyte encapsulated LiClO₄, LiAsF_6, LiBF₄, LiPF_6 lithium salts and ethylene carbonate(EC), propylene carbonate(PC) organic solvent in polyacrylonitrile(PAN) matrix were investigated. The ionic conductivity of polymer electrolyte of all the composition showed in the range 10^(-3)-10^(-4)s/㎝ at room temperature. The interfacial resistance between lithium electrode and polymer electrolyte with time was the most stable when EC/PC organic solvent ratio is 75 : 25. The ionic conductivity and interfacial resistance of polymer electrolyte containing lithium salt LiPF_6 in this solvent ratio showed stable value with storage time. This electrolyte was electrochemically stable up to 4.3 V(vs. Li^+/Li), so that it could be apply to lithium polymer battery. The diffusion coefficient of lithium ion in polymer electrolytes was 4×10^(-7) ㎠/sec and the exchange current density decreased with time.