• 제목/요약/키워드: activation ratio

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KOH 활성화법으로 제조한 폐감귤박 활성탄의 특성 (Characteristics of Activated Carbon Prepared from Waste Citrus Peel by KOH Activation)

  • 감상규;강경호;이민규
    • 공업화학
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    • 제28권6호
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    • pp.649-654
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    • 2017
  • 제주도에서 다량 발생하고 있는 폐감귤박을 활성화제로 KOH를 사용하여 활성탄을 제조하였고, 제조된 활성탄의 특성을 검토하였다. KOH 침적비율(100~300%), 활성화 온도($400{\sim}900^{\circ}C$) 및 활성화 시간(0.5~1.5 h)의 조건에서 각 조건이 증가할수록 요오드 흡착능은 증가하였으나 활성탄의 수율은 감소하였다. 그리고 활성화 시간의 경우 1.5 h 이상에서는 요오드 흡착능 및 활성탄 수율에서 비슷하였다. 또한 KOH 침적비율이 증가할수록 비표면적 및 세공부피는 증가하였으나 세공크기는 감소하였으며, 제조된 평균 세공크기는 $20{\sim}25{\AA}$이었다. KOH의 침적비율 300%, 활성화 온도 $900^{\circ}C$, 활성화 시간 1.5 h에서 제조된 활성탄은 비표면적 및 요오드 흡착능이 각각 $1,527m^2/g$ 및 1,246 mg/g으로 가장 높았다.

Effect of Activation Energy and Crystallization Kinetics of Polyethylenes on the Stability of Film Casting Processes

  • Lee, Joo-Sung;Cho, Joon-Hee
    • Korea-Australia Rheology Journal
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    • 제21권2호
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    • pp.135-141
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    • 2009
  • Effect of activation energy and crystallization kinetics of polyethylenes (PEs) on the dynamics and stability has been investigated by changing rheological properties and crystallization rate in film casting process. The effect of changes of these properties has been shown using a typical example of short-chain branching (SCB) in linear polyethylenes. SCBs in linear polymers generally lead to the increase of the flow activation energy, and to the decrease of the crystallization rate, making polymer viscosity lower in the case of equivalent molecular weight. In general, the increment of the crystallinity of polymers under partially crystallized state helps to enhance the process stability by increasing tension, and lower fluid viscoelasticity possesses the stabilizing effect for linear polymers. It has been found that the fluid viscoelasticity plays a key role in the control of process stability than crystallization kinetics which critically depends on the cooling to stabilize the film casting process of short-chain branched polymers operated under the low aspect ratio condition.

KOH 활성화에 의한 PAN계 활성탄소섬유의 제조 (The Preparation of PAN-based Activated Carbon Fiber by KOH)

  • 김기원;정승훈;임연수;정윤중
    • 한국세라믹학회지
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    • 제36권6호
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    • pp.577-582
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    • 1999
  • Activated carbon fibers were prepared from stabilized PAN fibers by chemical activation using hydroxide. The variations in specific surface area amount of iodine adsorption micro-structure and pore size distribution in the activated carbon fibers after the activation process were discussed. In the chemical activation using potassium hydroxide specific surface area of about 2545m2/g and amount of iodine adsorption of 2049 mg/g were obtained at the condition of KOH/fiber ratio of 1 and 800$^{\circ}C$ Nitrogen adsorption isotherms for PAN based activated carbon fibers showed the type I in the Brunauer-Deming-Deming-Teller classification indicating the micro-pores consisting the activated fibers.

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클램 운동 시 운동범위에 따른 엉덩관절 벌림근의 활성도와 사용 비교 (Comparison of Activity and Use of Hip Abductor Muscle Group According to Range of Motion during the Clam Exercise)

  • 최용길;이상열;최수홍;윤성영;김인균
    • PNF and Movement
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    • 제20권3호
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    • pp.341-349
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    • 2022
  • Purpose: The purpose of this study is to compare the muscle activity of the hip abductors and the ratio between the hip abductor muscle group according to the range of hip abduction during the clam exercise. Methods: This study was conducted on 18 healthy men in their aged 20 to 29 who had not been diagnosed with spine-related diseases. The subjects performed a clam exercise without rotation of the pelvis in a state of 60° hip flexion and 90° knee joint flexion in the side-lying position. Using Myomotion equipment and EMG, the muscle activity of the hip abductor muscles and the activity ratio between the hip abductor muscle group were measured during the clam exercise by dividing the range into initial, mid-range, and terminal sections. Repeated measures analysis of variants was employed to compare the activity and use of hip abductor muscles according to range of motion during the clam exercise. Results: Gluteus medius muscle activation was significantly increased in the comparison of muscle activity in the initial, mid-range, and terminal sections of hip abduction. Tensor fasciae latae muscle activation was significantly increased in the comparison of muscle activity in all range of motion sections as well. The gluteus medius-tensor fasciae latae muscle activation ratio was significantly increased in the terminal section compared to the initial section. Conclusion: The gluteus medius and tensor fasciae latae had higher muscle activities as they approached the terminal section during the clam exercise, and the hip abduction activity ratio of the gluteus medius and tensor fasciae latae was higher as the range of motion approached the terminal section.

커피폐기물을 이용한 활성탄의 제조: ZnCl2-활성화 (The Preparation of Activated Carbon from Coffee Waste: ZnCl2-Activation)

  • 유상희;김학희
    • 공업화학
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    • 제9권4호
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    • pp.509-515
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    • 1998
  • 커피폐기물을 원료로 하여 염화아연으로 화학적 활성화시켜 커피활성탄 (activated coffee char)을 제조하였다. 이 연구는 roasting과정, 탄화과정, 활성화, 그리고 수세 및 건조의 공정으로 수행되었다. Roasting 과정은 $300{\sim}400^{\circ}C$에서 10분간 수행되었다. 탄화과정의 적절한 조건은 $650^{\circ}C$에서 1시간인 것으로 나타났다. 화학적 활성화에 있어서 가장 중요한 parameter는 활성화제와 coffee char의 화학비인 것을 알 수 있었다. $N_2$ gas를 이용하여 77K에서 제조된 커피활성탄의 BET 비표면적과 BJH 세공용적을 측정하였다. 염화아연에 의해 활성화되어 제조된 coffee char의 비표면적이 $1110{\sim}1580m^2/g$로 분석되었으며 세공용적은 $0.51{\sim}0.81cm^3/g$로 각각 분석되었다. SEM은 세공과 coffee char의 표면관찰에 이용되었다. 분석결과, 활성화 표면과 많은 세공이 형성되어 있는 것을 보였다. 커피폐기물을 이용한 activated coffee char의 제조가 성공적으로 수행되었으며, 이는 폐기물을 이용한 자원 개발의 가능성을 보여주었다.

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K2CO3 처리된 Coal Tar Pitch 활성탄 전극의 결정성 및 EDLC 성능 (Structural Characterization and EDLC-Electrode Performance of Coal-Tar-Pitch Activated Carbon Using K2CO3 Treatment)

  • 최푸름;정지철;임연수;김명수
    • 한국재료학회지
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    • 제26권9호
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    • pp.460-467
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    • 2016
  • Activated carbons (ACs) have been used as EDLC (electric double-layer capacitor) electrode materials due to their high specific area, stability, and ecological advantages. In order to prepare ACs with high density and crystallinity, coal tar pitch (CTP) was activated by $K_2CO_3$ and the textural and electrochemical properties of the obtained ACs were investigated. Although the CTP ACs formed by $K_2CO_3$ activation had much smaller specific surface area and pore volume than did the CTP ACs formed by KOH activation, their volumetric specific capacitance (F/cc) levels as electrode materials for EDLC were comparable due to their higher density and micro-crystallinity. Structural characterization and EDLC-electrode performance were studied with different activation conditions of $CTP/K_2CO_3$ ratio, activation temperature, and activation period.

Characterization of neutron spectra for NAA irradiation holes in H-LPRR through Monte Carlo simulation

  • Kyung-O Kim;Gyuhong Roh;Byungchul Lee
    • Nuclear Engineering and Technology
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    • 제54권11호
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    • pp.4226-4230
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    • 2022
  • The Korea Atomic Energy Research Institute (KAERI) has designed a Hybrid-Low Power Research Reactor (H-LPRR) which can be used for critical assembly and conventional research reactor as well. It is an open tank-in-pool type research reactor (Thermal Power: 50 kWth) of which the most important applications are Neutron Activation Analysis (NAA), Radioisotope (RI) production, education and training. There are eight irradiation holes on the edge of the reactor core: IR (6 holes for RI production) and NA (2 holes for NAA) holes. In order to quantify the elemental concentration in target samples through the Instrumental Neutron Activation Analysis (INAA), it is necessary to measure neutron spectrum parameters such as thermal neutron flux, the deviation from the ideal 1/E epithermal neutron flux distribution (α), and the thermal-to-epithermal neutron flux ratio (f) for the irradiation holes. In this study, the MCNP6.1 code and FORTRAN 90 language are applied to determine the parameters for the two irradiation holes (NA-SW and NA-NW) in H-LPRR, and in particular its α and f parameters are compared to values of other research reactors. The results confirmed that the neutron irradiation holes in H-LPRR are designed to be sufficiently applied to neutron activation analysis, and its performance is comparable to that of foreign research reactors including the TRIGA MARK II.

Chemical Activation Characteristics of Pitch-Based Carbon Fibers by KOH

  • Jang, Jeen-Seok;Lee, Young-Seak;Kim, In-Ki;Yim, Going
    • Carbon letters
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    • 제1권2호
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    • pp.69-75
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    • 2000
  • Naphtha cracking bottom oil was reformed with heat treatment and then spun at $310^{\circ}C$. These pitch-based carbon fibers were carbonized at $1000^{\circ}C$ after oxidation at $280^{\circ}C$, for 90 min. These fibers were chemically activated with molar ratio of KOH/CF (1 : 1) at different temperatures ($250{\sim}900^{\circ}C$) for 1 hr. The process of activation was characterized with DTA, TGA, BET surface area and pore size distribution. The activation of fibers by KOH was performed by several process. One is the reduction process that carbon fiber was reacted with $K_2O$ produced from dehydration process above $400^{\circ}C$. The other is the process that $K_2CO_3$ was directly reacted with carbon fiber. At $800^{\circ}C$, the activation was performed by catalyzed mechanism that $K_2O$ was obtained from the reaction of metal potassium with $CO_2$, then was changed to $K_2CO_3$. At $870^{\circ}C$, the activation was also observed that activation mechanism was promoted by metal catalyst with $CO_2$ from decomposition of $K_2CO_3$. The specific surface area of prepared activated carbon fibers was dependent on the activation mechanism. The specific surface area was in the range of $1519{\sim}2000\;cm^3/g$ and was the largest prepared at $870^{\circ}C$. The pores developed were mostly micropores which was very narrow and uniform. The total pore volume was $0.58{\sim}0.77\;cm^3/g$.

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KOH 활성화에 의한 피치계 고품질 활성탄의 제조 및 특성 (Preparation and Characterization of high-quality activated carbon by KOH activation of pitch precursors)

  • 이은지;권순형;최푸름;우종표;정지철;김명수
    • 한국응용과학기술학회지
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    • 제31권3호
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    • pp.408-415
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    • 2014
  • In order to prepare high-quality activated carbons (ACs), coal tar pitch (CTP), and mixtures of CTP and petroleum pitch (PP) were activated with KOH. The ACs prepared by activation of CTP in the range of $700{\sim}1000^{\circ}C$ for 1~5 h had very porous textures with large specific surface areas of $2470{\sim}3081m^2/g$. The optimal activation conditions of CTP were determined as CTP/KOH ratio of 1:4, activation temperature of $900^{\circ}C$, and activation time of 3 h. The obtained AC showed the highest micro-pore volume, and pretty high specific surface area and meso-pore volume. The micro-pore volumes and specific areas of activated mixtures of CTP and PP were similar to each other but the meso-pore volume could be increased. In order to change the degree of crystallinity of precursors before KOH activation process, the CTPs were carbonized in the range of $500{\sim}900^{\circ}C$. As the carbonization temperature increased, the specific surface area and pore volume of the activated ACs with the same activation conditions for CTP decreased dramatically. It was demonstrated that the increased pore size distribution of AC electrodes in the range of 1 to 2 nm plays an important role in the performance of electric double-layer capacitor.

가로공간의 활성화 인자에 관한 연구 - 한국과 일본의 가로구성인자분석을 중심으로 - (A study on the activating factors of street spaces - Focused on the analysis of the component factors of streets in Korea and Japan -)

  • 이재원
    • 디자인학연구
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    • 제19권2호
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    • pp.99-108
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    • 2006
  • 본 연구는 이미 발표된 '가로공간의 번화함을 만드는 요소에 관한 연구'와 '가로경관의 이미지 평가에 관한 연구'에서 도출된 결과를 토대로 지속되는 연구로서 가로공간을 구성하는 구조적인자 이외에 어떤 인자가 가로공간의 이미지를 활기차게 조성하는 인자로 영향력 이 있는지를 알아보기 위한 연구이다. 우선, 선행연구 2편에서 연구대상으로 사용되어진 가로 중에서 가로공간의 구조비율($D/H=0.5{\sim}2$)에 의해 흥미로운 이미지를 갖는 가로가 된다는 이론에 합당한 구조를 가진 가로를 중점적인 연구 대상으로 하였다. 그 다음으로 가로구조비율에 의해 쾌적함이나 번화함의 이미지가 있다고 인지되어진 가로를 연구대상으로 하였다. 가로가 쾌적함이나 번화함이 있다고 느끼는 것은 그 가로가 활성화되었다는 의미로 한정하고 가로활성화인자를 가로구성요소에서 추출하고자 하였다. 그리고 가로가 활성화되어서 쾌적한 이미지 또는 번화한 이미지를 느낄 수 있는 가로를 본 연구에서는 '활기찬 가로'라고 명명하였다. 또, 조사지 역도 선행연구와 동등하게 국가별 지역특성별로 구분하여 20개의 가로를 선정하였고 그 중에서 $D/H=0.5{\sim}2$를 벗어난 가로가 활기찬 가로로 느껴질 경우에는 어떤 인자에 의한 영향인지도 알아보고자 하였다. 그 결과, D/H=0.5-2인 업무지역가로인 경우 가로공간 활성화인자로는 수경시설, 보도, 연도건물인자 순으로 많은 영향을 준다는 것을 알 수 있었으며, 상업지역의 가로의 활성화인자로는 보도, 연도건물, 수경시설 및 조명시설인자순인 것을 알 수 있었다. 특히 $D/H=0.5{\sim}2$를 벗어난 가로구조를 가진 한국의 상업지역가로 5개와 일본의 업무지역가로 1개는 흥미로운 이미지를 갖는 구조를 벗어나면서도 활기찬 가로의 이미지를 갖게 되는 것은 가로공간의 구조적요소 이외에 가로공간 활성화인자에 의해 많은 영향을 받고 있다는 것을 알 수 있었다. 즉, 이런 구조를 가진 한국의 상업지역의 가로인 경우 연도건물, 보도, 수경시설 등의 인자 순으로, 일본의 업무지역의 가로인 경우 수경시설, 연도건물, 보도인자 순으로 가로활성화에 영향을 주고 있다는 것을 알 수 있었다.

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