• Journal of the Korean Electrochemical Society
• /
• v.16 no.3
• /
• pp.145-150
• /
• 2013

In this study, the electrochemical investigation of various electrodes for reverse electrodialysis using potassium ferrocyanide and potassium ferricyanide as a redox system was carried out. Cyclic voltammetry was the employed method for this electrochemical study. From the results of cyclic voltammograms for various electrode materials, i.e., Au, Vulcan supported Pt, activated carbon, carbon nanofiber, Vulcan, the Vulcan electrode showed the lowest overpotential, but the Pt electrode having slightly higher overpotential obtained slightly higher anodic and cathodic current densities for the $Fe(CN)_6{^{4-}}/Fe(CN)_6{^{3-}}$ redox couple. The cyclic voltammograms for the Vulcan electrode confirmed very good electrochemical reversibility and kinetic behavior. As a result, among the electrode materials, the Vulcan electrode is the most promising electrode material for reverse electrodialysis.

• Journal of Energy Engineering
• /
• v.23 no.3
• /
• pp.150-156
• /
• 2014

In this study, we implemented a research for improving performance of redox flow battery (RFB) via enhancing reaction rate of vanadium reaction ($[VO]^{2+}/[VO_2]^+$) that was a rate determining step. For doing that, porous catalyst, CMK3 was employed and its perfoamance was compared with that of Vulcan(XC-72) and commercial Pt/C (Johnson-Matthey Pt 20wt.%). Cyclic voltammetry (CV) was used for inspecting reactivity, while its structural feature was measured by TEM and BET&BJH. Also, Charge-discharge trend was evaluated by single cell tests. As result, CMK3 showed 6 times better catalytic activity and twice better reversibility than Vulcan(XC-72), while it showed larger surface area than Vulcan XR due to its porous structure. Furthermore, CMK3 indicated 85% of reactivity and reversibility of commercial Pt/C despite its Pt-less situation. In single cell tests, when RFB adopted CMK3 as catalyst for positive electrode, its charge-discharge curve result was better than that adopted commercial Pt/C.

• Applied Chemistry for Engineering
• /
• v.16 no.5
• /
• pp.689-692
• /
• 2005

In order to improve the electrochemical performances of Li-ion batteries when spinel $LiMn_2O_4$ is employed as a cathode active material, binary conductive agents were prepared using two different particle-sized carbons like Super P Black and $Vulcan^{(R)}$ XC-72R. The electrochemical performances of the $LiMn_2O_4$ cell system using binary conductive agents were evaluated in terms of specific charge and discharge capacities and cycle life. The cell with binary conductive agent in the 3:7 weight ratios of Super P Black and $Vulcan^{(R)}$ XC-72R showed better electrochemical performances due to the proper combination of ionic diffusion rate and electric contact.

• Journal of Plant Biotechnology
• /
• v.47 no.1
• /
• pp.40-45
• /
• 2020

An efficient protocol for multiple shoot induction and plant regeneration from axillary bud culture of Magnolia 'Vulcan' was developed in the present study. Primary shoots were obtained from axillary bud explants cultured on Murashige and Skoog (MS) medium containing 1.0 mg/L 6-benzylaminopurine (BA). To induce multiple shoots effectively, primary shoot tips were cultured on MS medium supplemented with different concentrations of BA and zeatin at 0, 0.2, 0.5, and 1.0 mg/L. Of these treatments, the MS medium with 0.5 mg/L BA resulted in the highest number of shoots per explant with an average value of 5.9, and it produced the greatest shoot height at 4.8 cm after 12 weeks of culturing. In the rooting of in vitro produced shoots, the greatest percentage of explants forming roots (91.3%), number of roots per explant (9.7), and root length (2.8 cm) were obtained in half-strength MS medium supplemented with 6.0 mg/L indole-3-butyric acid (IBA). Regenerated plantlets were successfully acclimatized and hardened off inside the culture room with 87.5% survival rate. Plants were transferred to a greenhouse with a 97.2% survival rate. The highly efficient shoot multiplication and plant regeneration system reported herein can be used for large-scale clonal propagation of valuable Magnolia species or cultivars.

• The Science & Technology
• /
• no.2 s.405
• /
• pp.10-15
• /
• 2003

우리가 사는 지구 내부에서 만물을 순식간에 녹여버릴 듯한 불덩이가 솟구치는데, 그것을 화산이라고 한다. 화산이라는 용어인 volcano는 '불의 신'이라 불리는 'vulcan'에서 유래되었다. 즉, 이 '불의 신'이 끓어오르는 '화기(火氣)'를 주체하지 못할 때 화산활동은 시작되는 것이다. 화산활동이 일어나는 지역의 원시부족들은 불을 내뿜는 화산을 '신의 분노' 혹은 '신의 저주'라고 해석한다.

• Transactions of the Korean hydrogen and new energy society
• /
• v.2 no.1
• /
• pp.57-67
• /
• 1990

This study is proposed to investigate the effect of electrode preparation method for Alkaline Fuel Cell using NaOH as an electrolyte on the Fuel Cell performance. The materials used for the preparation of electrode are Pt and Ag on Vulcan XC-72. Surface area of Vulcan XC-72 have different values according to the pretreatment conditions and the dispersion of Pt is dependent on the impregnation Particle size of Pt impregnated on unpretreated carbon was observed to be $20{\sim}40{\AA}$ and that on pretreated carbon in $N_2$ stream at $950^{\circ}C$ was found to be finely dispersed less then $15{\AA}$. The electrode performance was affected by the particle size of metals and operating temperature. It was revealed from this study that the optimum particle size about $30{\AA}$ and optimum temperature range is between $90{\sim}100^{\circ}C$.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.14 no.1
• /
• pp.65-78
• /
• 2010

DARPA carries out several R&D programs for hypersonic vehicles to maintain the U.S. military superiority in air and space. Falcon program is the core of the DARPA's activitiy for the hypersonics including the long-term step-by-step approach from HTV-1, HTV-2, HTV-3X to HCV. Hypersonic Turbo-Based Combined Cycle (TBCC) engine technologies research and development programs, HiSTED, FaCET and Vulcan, are also the parts of their activities. Present article presents the summarized review on the backgrounds, technologies and relationships of those programs.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.11a
• /
• pp.326-329
• /
• 2008

DARPA's hypersonic propulsion program VULCAN is aimed for development of Mach 4+ capable engine by combining current production turbofan engine such as F119 with CVC (Constant Volume Combustion) engine. Final goal is a TBCC(Turbo-based Combined Cycle) engine by combining with dual mode ramjet/scramjet engine. CVC is a common designation of new concept of high efficiency engines, such as Pulse Detonation Engine (PDE) or Continuous Detonation Engine (CDE), which use the detonation as a combustion mechanism. Present paper introduces the internationally collaborative research activities carried out in Aerospace Combustion and Propulsion Laboratory of the department of Aerospace Engineering of the Pusan national University.

• Journal of Powder Materials
• /
• v.12 no.2 s.49
• /
• pp.117-121
• /
• 2005

Platinum catalysts for the DMFC (Direct Methanol Fuel Cell) were impregnated on several carbon supports and their catalytic activities were evaluated with cyclic voltammograms of methanol electro-oxidation. To increase the activities of the Pt/C catalyst, carbon supports with high electric conductivity such as mesoporous carbon, carbon nanofiber, and carbon nanotube were employed. The Pt/e-CNF (etched carbon nanofiber) catalyst showed higher maximum current density of $70 mA cm^{-2}$ and lower on-set voltage of 0.54 V vs. NHE than the Pt/Vulcan XC-72 in methanol oxidation. Although the carbon named by CNT (carbon nanotube) series turned out to have larger BET surface area than the carbon named by CNF (carbon nanofiber) series, the Pt catalysts supported on the CNT series were less active than those on the CNF series due to their lower electric conductivity and lower availability of pores for Pt loading. Considering that the BET surface area and electric conductivity of the e-CNF were similar to those of the Vulcan XC-72, smaller Pt particle size of the Pt/e-CNF catalyst and stronger metal-support interaction were believed to be the main reason for its higher catalytic activity.

• International Journal of High-Rise Buildings
• /
• v.2 no.1
• /
• pp.1-9
• /
• 2013

This paper reviews the recent developments in fire engineering and the design approaches which are being used in the UK, compared with traditional prescriptive solutions. The research background which has underpinned this is briefly summarised, and the benefits of these more advanced methods are discussed. The focus is on structural fire engineering, but some consideration of modelling fires is also included. Some of the more commonly used design tools are discussed, together with the relative benefits they offer. The use of these more advanced approaches is then outlined in the context of which building types might be most suitable, and a number of case studies are included to illustrate this. Likely future developments are also discussed.