http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Bosung Rhee (검색결과 7 건)
- 무료
- 기관 내 무료
- 유료
-
Pyrocarbon Whisker Growth on the Catalytic Mullite Substrate by the Pyrolysis of Methane
Bosung Rhee,Young-Tae Park 한국탄소학회 2005 Carbon Letters Vol.6 No.2
Like bamboo-sprouts after rains, numerous subμm-sized pyrocarbon whiskers growth on the Mullite (3Al2O3·2H2O) substrate could be observed through a looking glass during methane pyrolysis at the temperature of 1050℃ in this study. If the surface of substrate would be scrubbed strongly with iron metals, then finely sticked iron particles were more effective catalytic for nm-sized whisker growth. Numerous fine flakes of pyrolytic carbon were hanging by invisible nm-whiskers as like as small spiders hanging by a spiderweb. This is the identification of nm-sized whisker growth. Therefore if the pyrolysis would be stopped at the initial stage of the whisker growth, the primary lengthening growth was nm-sized whisker. So could we vary arbitrarily sizes of whisker from nm- to μm-sizes. But μm- and nm-whiskers grown with the different growth mechanism; the former was straight and the latter has twigs, The lengthening growth of whisker was depended on the flow pattern pyrolysis species on the active sites of substrate and on the growth duration. We could obtained straight whisker length of 10~20 μm/min during the primary growth and laboratory spiral whisker of 30~40 μm-diameter/hr during the secondary growth.
-
Pyrocarbon Whisker Growth on the Catalytic Mullite Substrate by the Pyrolysis of Methane
Rhee, Bosung,Park, Young-Tae Korean Carbon Society 2005 Carbon Letters Vol.6 No.2
Like bamboo-sprouts after rains, numerous sub${\mu}m$-sized pyrocarbon whiskers growth on the Mullite ($3Al_2O_3{\cdot}2H_2O$) substrate could be observed through a looking glass during methane pyrolysis at the temperature of $1050^{\circ}C$ in this study. If the surface of substrate would be scrubbed strongly with iron metals, then finely sticked iron particles were more effective catalytic for nm-sized whisker growth. Numerous fine flakes of pyrolytic carbon were hanging by invisible nm-whiskers as like as small spiders hanging by a spiderweb. This is the identification of nm-sized whisker growth. Therefore if the pyrolysis would be stopped at the initial stage of the whisker growth, the primary lengthening growth was nm-sized whisker. So could we vary arbitrarily sizes of whisker from nm- to ${\mu}m$-sizes. But ${\mu}m$- and nm-whiskers grown with the different growth mechanism; the former was straight and the latter has twigs, The lengthening growth of whisker was depended on the flow pattern pyrolysis species on the active sites of substrate and on the growth duration. We could obtained straight whisker length of 10~20 ${\mu}m$/min during the primary growth and laboratory spiral whisker of 30~40 ${\mu}m$-diameter/hr during the secondary growth.
-
이보성,주혁종 忠南大學校 1972 論文集 Vol.11 No.-
Die eigenen Versuche zur Versta¨rkung von Thermoduren mit Kohlenstoffasern haben gezeigt, daβ das Naβwickelverfahren bei ausreichem Fadenzug un anschlieβender Aushartung unter Preβdruck zur fehlerfeien Verbundko¨rpern fu¨hrt, Zugfestigkeit und Elastizita¨tsmodul der Verbundko¨rper grenzen and die aus den Eigenschaften der reinen Komponenten vorausberechenbaren Eigenschaftswerte des Verbundes und man erreicht mit der Niedermodul-Kohlenstoffaser auf 40Kp/㎟. Die Ha¨rtungsschwindung der Matrix bringt demnach keine wesentliche Probleme mit sich.
-
알칼리 영역에서 용존산소에 의한 제일철 이온의 산화반응속도
이보성,고재천,이정민 한국화학공학회 1987 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.25 No.5
알칼리 수용액에서 이가철 이온이 용존산소에 의하여 산화되는 산화속도를 초기농도 측정법에 따라 측정하여 반응차수를 구하고 산화반응기구를 추정하였으며 활성화에너지를 구하였다. 각각의 농도에 대한 산화반응차수는 이가철 이온농도에 대하여 1차였으며, 알칼리농도에 대한 반응차수는 알칼리농도가 0.025mole/ℓ 부근에서 양의 차수에서 음의 차수로 변화되는 변곡점이 있음을 알았다. 용존산소에 의한 제일철의 산화반응속도식은 30℃ 이하에서 -d[O₂]/dt=k'[Fe^(II)][OH^-]^½[O₂]^¾/(K_(FeOH+)^+ [OH^-])이었고 40℃에서 -d[O₂]/dt=k"[Fe^(II)][OH^-][O₂]^½/(K_(FeOH+)^+ [OH^-])로 나타낼 수 있었으며 산화에 필요한 활성화에너지는 6.8Kcal/mole이었다. 본 연구에서 제일철 이온의 산화생성물은 무정형 함수산화철인 δ-FeOOH임을 X-선회절 및 IR로서 확인하였다. The kinetics for the oxidation reaction of ferrous ion in alkaline solution in with the dissolved oxygen was determined using initial rate method. The oxidation was conducted by injecting the ferrous ion into NaOH solution and the reaction orders in terms of oxygen consumption were the first order with respect to the ferrous ion concentration but varied with the alkali and the dissolved oxygen concentration. The deflection of reaction order with respect to alkali concentration was found to occur near 0.025 mole/l NaOH concentration. The rate equations for the oxidation were two types according to the temperature level;one of these was -d[O₂]/dt=k'[Fe^(II)][OH^-]^½[O₂]^¾/(K_(FeOH+)^+ [OH^-]) bellow 30℃ and another -d[O₂]/dt=k"[Fe^(II)][OH^-][O₂]^½/(K_(FeOH+)^+ [OH^-]) at 40℃ The activation energy for the oxidation of ferrous ion was 6.8Kcal/ mole. Amorphous iron oxy-hydroxide (δ-FeOOH) which had produced as reacting the iron sulfate to the NaOH in the aforementioned solution was confirmed by the X-ray diffractometer and the IR spectrophotometer.
-
Sigrist,Lukas,Rhee,Bosung 한국화학공학회 1980 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.18 No.3
Measurements of mass transfer toward a gas sparged electrode with and without superimposed electrolyte flow will be reported. The mass transfer coefficient, measured by the well known limiting current method, depends mainly on the gas voidage fraction, irrespective of the fluid flow velocities. The system shows a striking analogy with turbulent natalur convection and the results can be represented formally by the same dimensionless correlation replacing the Grashof number by a modified Archimedes number.
-
-
침상형 α - Goethite 를 분산시킨 현탁기포탑에서의 기포경과 물질전달계수(2)
김범식,이보성,이정민,고재천,김철웅 한국화학공학회 1992 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.30 No.1
1N-NaOH 수용액에 미세한 침상형 α-Goethite(평균길이 0.27 ㎛)가 현탁된 기포탑에서 물질전달 현상에 대하여 연구하였다. 기포경을 측정하기 위하여 2-point probe를 사용하였다. 측정된 기포경은 log-normal분포를 나타냈으며 공탑속도와 현학농도의 증가에 따라 기포경의 분포는 unimodal에서 multimodal로 변화되었다. 계산된 Sauter 평균 기포경(d_(vs), volume-to-surface mean bubble diameter)은 공탑속도와 현학농도의 증가에 따라 최소치를 보인 후 증가하는 경향을 보였다. 물질전달계수(k_L)는 0.9wt% 미만에서 증가현상을 보였으며 0.9wt% 이상일 경우 고체농도의 증가에 따라 급격히 감소하였고, 또한 Sauter 평균 기포경(d_(vs))이 커짐에 따라 증가현상을 보였다. 본 현탁기포탑에서의 물질전달계수는 아래와 같이 무차원군과 고체농도비(wt%)의 항으로 잘 나타낼 수 있었다. Sh= 1.0×10^(-5)Sc^(1.53)Re^(0.79)Bo^(0.51)/(1+8.×Ф^(2.73)) Mass transfer phenomena were studied in a studied bubble column in which fine acicular α-Goethite particles(average length 0.27 ㎛) were suspended in 1N-NaOH solution. In order to measure bubble diameter, two-point probe was used. Distribution of measured bubble diameters in the slurry bubble column was showed log-normal and changed from unimodal to multimodal with increasing the superficial gas velocity and solid concentration. Sauter mean bubble diameter(d_(vs), volume-to-surface mean bubble diameter) was minimized at transition region, but above that region, it was increased by increasing superficial gas velocity and solid concentrations. Liquid side mass transfer coefficient(k_L) was increased below 0.9 wt% solid concentration but was suddenly decreased above 0.9 wt% by concentrating the solid. The k_L was also increased with increasing the Sauter mean bubble diameter. Liquid side mass transfer coefficient can be represented as following equation by dimensionless groups and wt% concentration on this system and conditions. Sh =1.0×10^(-5)Sc^(1.53)Re^(0.79)Bo^(0.51)/(1+8.×Ф^(2.73))
스콜라
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
