• Journal of the Korean institute of surface engineering
• /
• v.12 no.2
• /
• pp.134-144
• /
• 1979

금회에는 평활한 도금을 하기위한 요인과 평활제와 광태제의 작용기구, 그리고 전류분포 흡장수소, 내부응력, 밀착성, 경도, 도금욕 관리를 위한 관점에서의 양극의거동 및 배수처리에 관한 기초문제에 관해 알아보고 끝을 맺겠다. 본 강좌는 현장 실무자를 위해 日本실務表面技術誌 1974년 9~12월호 75년 1~3월호에 연재되었던 것을 계제할것임을 밝힙니다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.17 no.9
• /
• pp.824-829
• /
• 2005

MHR(Metal Hydride Refrigerator) powered by MGT exhaust gas is investigated to find out the optimum conditions corresponding to MGT operating powers. There are many factors to affect cooling capacity of MHR. In this study, the effect of switching time, flow rate of brine on cooling temperature and capacity is investigated. The present results show (1) hydrogen reaction is saturated with 25 min switching time at 25 kW MGT power, (2) cooling power shows maximum phenomenon with increasing switching time, (3) optimum switching times are 20 minutes for 15kW MGT power and 15 minutes for 20, 25kW MGT power, (4) according to increasing brine flow rate, cooling capacity shows decrease at 15 kW MGT power and changes little at above 20 kW MGT power.

• Transactions of the Korean hydrogen and new energy society
• /
• v.23 no.1
• /
• pp.49-55
• /
• 2012

Hydrogen isotopes accountancy and storage are important functions in a nuclear fusion fuel cycle. The hydrogen isotopes are safely stored in metal hydride beds. The tritium inventory of the bed is determined from the decay heat of tritium. The decay heat is measured by circulating helium through the metal hydride bed and measuring the resultant temperature increase of the helium flow. We are reporting our preliminary experimental results on the hydrogen isotopes accountancy and storage performance in a metal hydride bed.

• Transactions of the Korean hydrogen and new energy society
• /
• v.5 no.1
• /
• pp.9-17
• /
• 1994

Activation behavior, hydriding rate and disintegration were studied for a compact in pellet form and hydrogen storage alloy particles treated with newly developed inorganic solution. Cylindrical disc of 12.95mm diameter and of 7.1mm thickness was prepared by compressing(8ton) a mixture of $MmNi_{4.5}Al_{0.47}$ and PTFE. Chemical treatment of particles with 1mol of solution was performed at room temperature for several hours until the pH of solution did not change. Chemical treatment made much accelerated activation without any incubation period which generally exists in the untreated alloys and the hydriding reaction rate after full activation also was improved.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.7
• /
• pp.689-696
• /
• 2010

The Because of its high thermal efficiency, the direct injection (DI) diesel engine has emerged as a promising potential candidate in the field of transportation. However, the amount of nitrogen oxides ($NO_x$) increases in the local high-temperature regions and that of particulate matter (PM) increases in the diffusion flame region during diesel combustion. In the de-$NO_x$ system the Lean $NO_x$ Trap (LNT) catalyst is used, which absorbs $NO_x$ under lean exhaust gas conditions and releases it in rich conditions. This technology can provide a high $NO_x$-conversion efficiency, but the right amount of reducing agent should be supplied to the catalytic converter at the right time. In this research, the emission characteristics of a diesel engine equipped with a micro-reformer that acts as a reductants-supplying equipment were investigated using an LNT system, and the effects of the exhaust-gas temperature were also studied.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.20 no.7
• /
• pp.46-52
• /
• 2006

The effects of surface treatment on the hydrogen storage properties of a $Mg_2Ni$ alloy particle were investigated by the microvoltammetric technique, in which a carbon-filament microelectrode was manipulated to make electrical contact with the particle in a KOH aqueous solution. It was found that the hydrogen storage properties of $Mg_2Ni$ at room temperature were improved by the surface treatment with a nickel plating solution. The sodium salts(sodium phosphate and sodium dihydrogen citrate) contained in the nickel plating solution made the alloy form an amorphous-like state, resulting in an improved hydrogen charge/discharge capacity at room temperature as high as about 150[mAh/g] from the original value of 17[mAh/g]. Potential-step experiment was carried out to determine the apparent chemical diffusion coefficient of hydrogen atom($D_{app}$) in the alloy. Since the alloy particle we used here was a dense, conductive sphere, the spherical diffusion model was employed for data analysis. $D_{app}$ was found to vary the order between $10^{-8}{\sim}10^{-9}[cm^2/s]$ over the course of hydrogenation and dehydrogenation process.

• Applied Chemistry for Engineering
• /
• v.5 no.2
• /
• pp.263-273
• /
• 1994

Titanium powder prepared by dehydrogenating the titanium hydride which is synthesized by reacting Ti-sponge (99.67%) with hydrogen using the self-propagating high-temperature synthesis method. In the synthesis of titanium hydride, the particle size of the product was found dependent on the amount of hydrogen incorporated into the titanium such that the particle size of titanium hydride decreased with increasing hydrogen pressure and after-burn time. In the dehydrogenation process, as the dehydrogenation time increase, the particle size of titanium powder increased due to partial melting and sintering of titanium particles.

• Transactions of the Korean hydrogen and new energy society
• /
• v.18 no.4
• /
• pp.399-405
• /
• 2007

The hyper-eutectic Mg-33.5%Ni alloy was rapidly solidified by melt spinning process. The melt-spun Mg-33.5%Ni has amorphous structure and crystallization occurred above $162^{\circ}C$. The hydriding and dehydriding rates of melt-spun Mg-33.5%Ni increased with cycle and high rate of hydrogen storage occurred at 3rd cycle. The maximum hydrogen amount absorbed in melt-spun Mg-33.5%Ni at $300^{\circ}C$ is about 4.5%.

• Proceedings of the SAREK Conference
• /
• 2004.06a
• /
• pp.91-91
• /
• 2004

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.225.1-225.1
• /
• 2010

Within recent years attention has been focused on the method of hydrogen storage using metal hydride reactor due to its high energy density, durability, safety and low operating pressure. In this paper, a numerical study is carried out to investigate the coupled heat and mass transfer process for absorption in a cylindrical metal hydride hydrogen storage reactor using a newly developed model. The simulation results demonstrate the evolution of temperature, equilibrium pressure, H/M atomic ratio and velocity distribution as time goes by. Initially, hydrogen is absorbed earlier from near the wall which sets the cooling boundary condition owing to that absorption process is exothermic reaction. Temperature increases rapidly in entire region at the beginning stage due to the initial low temperature and enough metal surface for hydrogen absorption. As time goes by, temperature decreases slowly from the wall region due to the better heat removal. Equilibrium pressure distribution appears similarly with temperature distribution for reasons of the function of temperature. This work provides a detailed insight into the mechanism and corresponding physicochemical phenomena in the reactor during the hydrogen absorption process.