• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.226-226
• /
• 2012

The electronic and electrical properties of nickel oxide (NiO) thin films were investigated by reflection electron energy loss spectroscopy (REELS), x-ray photoelectron spectroscopy (XPS), and Hall Effect measurements. REELS spectra revealed that the band gap of the NiO thin film was increased from 3.50 eV to 4.02 eV after annealing the sample at $800^{\circ}C$. Our XPS spectra showed that the amount of Ni2O3 decreased after annealing. The Hall Effect results showed that the doping type of the sample changed from n type to p type after annealing. The resistivity decreased drastically from $4.6{\times}10^3$ to $3.5{\times}10^{-2}$ ${\Omega}{\cdot}cm$. The mobility of NiO thin films was changed form $3.29{\times}10^3$ to $3.09{\times}10^5cm^2/V{\cdot}s$. Our results showed that the annealing temperature plays a crucial role in increasing the carrier concentration and the mobility which leads to lowering resistivity of NiO thin films.

• Journal of Welding and Joining
• /
• v.11 no.2
• /
• pp.53-61
• /
• 1993

One of the most interesting and promising steel groups considered for the rocket motor case, aircraft and aerospace component is the maraging(martensitic plus aging) nickel steel, developed by International Nickel Company in 1960. This material attains a very high strength with good fracture toughness by simple heat treatments which do not involve a quenching. Full strength can be obtained by "maraging" at 480.deg. for 3 hours for the 18% Ni maraging steel. The effect of heat treatments was considered on the residual stress field of 18% Ni maraging steel weldments. In experiments, various heat treatments such as stress relieve heat treatment, aging and solution heat treatment were carried out of the GTA weldments and the residual stresses were measured by using the hole drilling method. Whereas the conventional pattern of residual stress shows the stresses to be maximum along the weld centerline with tensile stress extending into the heat affected zone, the pattern in maraging steels shows the centerline stress to be compressive. After welding, a series of aging, solution heat treatment and solution heat treatment plus aging treatment were carried out and the residual stresses were measured to reveal that these heat treatments almost completely remove the welding residual stresses.

• Applied Biological Chemistry
• /
• v.39 no.4
• /
• pp.293-296
• /
• 1996

The present study was carried out to investigate the effect of Ni on germination, cell elongation, ${\alpha}-amylase$ activity, contents of chlorophyll and protein in radish were determined in the water culture. As the concentration of Ni was increased in the water culture, germination of radish was 55% by Ni 10 mg/kg and 30% by Ni 20 mg/kg. The ratio of cell elongation injury was 50%, by two days after Ni 20 mg/kg treatment. The injury ratio of ${\alpha}-amylase$ activity was 45% in the same condition and as the time goes on, inhibition of ${\alpha}-amylase$ activity were slightly decreased. Contents of chlorophyll a and b were decreased two days after treatment and chlorophyll a was more inhibited than chlorophyll b. Also changes of the protein contents was slightly decreased. Activity of ${\alpha}-amylase$ was decreased at germination stage, contents of chlorophyll a and b were decreased at growing stage.

• Journal of Korea Foundry Society
• /
• v.26 no.4
• /
• pp.180-183
• /
• 2006

The effects of adding Ni on microstructure and mechanical properties of Nodular Indefinite Chilled Iron (NICI) were studied. Thermal fatigue, hardness, tensile properties, wear resistance, are very important factors for NICI used for hot working roll and wire rod mill. The results show that addition 4% nickel has changed pearlite to bainite. Bainite matrix is superior to pearlite matrix on wear resistance, hardness and strength and will increase performance lifetime of NICI conventional roll material. Based in the bainitic microstructure, hardness and tensile property increase up to 48 HRc and $72\;kg/mm^2$, respectively.

• Environmental Engineering Research
• /
• v.10 no.3
• /
• pp.131-137
• /
• 2005

The catalytic activity of precious metals(Rh, Pd, Pt) and nickel catalysts supported on ${\gamma}-Al_2O_3\;and\;CeO_2$ in the partial combustion of methane(PCM) to syngas was investigated based on the product distribution in a fixed bed now reactor under atmospheric condition and also on analysis results by SEM, XPS, TPD, BET, and XRD. The activity of the catalysts based on the syngas yield increased in the sequence $Rh(5)/CeO_2{\geq}Ni(5)/CeO_2>>Rh(5)/Al_2O_3>Pd(5)/Al_2O_3>Ni(5)/Al_2O_3$. Compared to the precious catalysts, the syngas yield and stability of the $Ni(5)/CeO_2$ catalyst were almost similar to $(5)/CeO_2$ catalyst, and superior to these of any other catalysts. The syngas yield of $Ni(5)/CeO_2$ catalyst was 90.66% at 1023 K. It could be suggested to be the redox cycle of the successive reaction and formation of active site, $Ni^{2-}$ and the lattice oxygen, $O^{2-}$ produced due to reduction of $Ce^{4-}$ to $Ce^{3-}$.

• Advances in nano research
• /
• v.14 no.2
• /
• pp.195-200
• /
• 2023

Safety in sports is important because if an athlete has an accident, he may not be able to lead an everyday life for the rest of his life. The safety of sports facilities is very effective in creating people's sports activities, with the benefits of staying away from physical injury, enjoying sports, and mental peace. Everyone has the right to participate in sports and recreation and to ensure that they want a safe environment. This study prepares a very good Nickel-Cobalt -Silicon carbide (Ni/Co-SiC) nanocomposite with convenient geometry on the leg press machine rod, employing the pulse electrodeposition technique to reduce the rod's wear and increase the durability of sports equipment and control sports damages. The results showed that the Ni/Co-SiC nanocomposite formed at 2 A/dm2 shows extraordinary microhardness. The wear speed for the Ni/Co-SiC nanocomposite created at 4 A/dm2 was 15 mg/min, showing superior wear resistance. Therefore, the Ni/Co-SiC nanocomposite can reduce sports equipment's wear and decrease sports injuries. Ni-Co/SiC nanocomposite layers with various scopes of silicon carbide nanoparticles via electrodeposition in a Ni-Co plating bath, including SiC nanoparticles to be co-deposited. The form and dimensions of Silicon carbide nanoparticles are watched and selected using Scanning Electron Microscopy (SEM).

• Journal of Sensor Science and Technology
• /
• v.33 no.5
• /
• pp.353-358
• /
• 2024

Al-Ni thin films were fabricated using combinatorial sputtering system to realize highly sensitive surface acoustic wave (SAW) devices. The Al-Ni sample library was grown with various chemical compositions and electrical resistivities, which provided important information for selecting the most suitable materials for SAW devices. As acoustic waves generated from piezoelectric materials are significantly affected by the resistivity and density of the interdigital transducer (IDT) electrodes, three types of Al-Ni thin films with different Al contents were fabricated. The thickness of the Al-Ni thin film used in the SAW-IDT electrode was fixed at 100 nm. As the Al content of the Al-Ni film decreased from 79.2 to 24.5 at%, the resistivity increased slightly from 4.8 to 5.8 × 10^-5 Ω-cm, whereas the calculated density increased significantly from 3.6 to 6.9 g/cm³. The SAW device composed of Al-Ni IDT electrodes resonated at 71 MHz without frequency shifts; however, the selectivity of the resonant frequency and insertion loss deteriorated as the Al content decreased. When there is no significant difference in the electrical characteristics of the SAW-IDT electrodes, the performance of the SAW devices can be determined by the density of the IDT electrodes.

• Environmental Mutagens and Carcinogens
• /
• v.19 no.1
• /
• pp.20-27
• /
• 1999

In order to know the inhibitory effect of magnesium carbonate(MgCO3) on cytotoxicity, DNA damage, mutagenicity, and cell transforming ability of nickel subsulfide, the inhibition of cell proliferation, DNA-protein crosslinks formation (DPC), HGPRT point mutation, and cell transformation were evaluated. Nickel subsulfide(Ni3S2) and magnesium carbonate as insoluble compounds were used for this study. BALB/3T3 cell, CHO-K1 cell, and C3H10T1/2 cell were used in this experiment. Exposure concentration of nickel subsulfide was 1 $\mu\textrm{g}$/ml. The concentrations of magnesium carbonate in this study were 0.6 $\mu\textrm{g}$/ml, 1.2 $\mu\textrm{g}$/ml, 2.4 $\mu\textrm{g}$/ml and the molar ratio of magnesium to nickel when exposed simultanously were 0.5, 1.0 and 2.0 respectively. The results were as follows; 1. Magnesium carbonate reduced the inhibitory effect of nickel subsulfide on cell proliferation. 2. Magnesium carbonate also reduced the effect of nickel subsulfide on DNA-protein crosslinks formation. 3. HGPRT point mutagenicity of nickel subsulfide was reduced when magnesium carbonate treated simultaneously. 4. Magnesium carbonate reduced cell transforming ability of nickel subsulfide. Conclusively, nickel subsulfide showed cytotoxicity, cell transforming ability, and mutagenicity strongly and magnesium carbonate may have protective roles in these nickel effects.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.270-274
• /
• 2001

With Increasing importance of electroless nickel plating technology in many fields such as electronic and automobile industries, the treatment of the spent baths is becoming a serious problem. These spent baths contain iron and zinc as impurities, organic acids as complexing reagents, and phosphonate ions as oxidized species of tile reducing reagent. as well as several grams per liter of nickel. The spent baths are currently treated by conventional precipitation method. but a mettled with no sludge generation is desired. This work aims at establishing a recycling process of nickel from tile spent baths using solvent extraction. Extraction behaviors of nickel. iron. and zinc in various 쇼pes of real spent baths are investigated as a function of pH using LIX841, di (2-ethylhexyl)phosphoric acid (D2EHPA), and PC88A as tile extractants. Nickel is extracted by LIX84I at the equilibrium pH of more than 6 with high efficiency. For the weakly acid baths. iron and zinc are extracted by D2EHPA or PC88A without adjusting the pH of the baths leaving nickel in the aqueous phase. Stripping of nickel from LIX84I with sulfuric acid is also investigated. It is shown that concentrated nickel sulfate solution (> 100 ㎏-Ni/㎥) is obtained. This solution can be reused in the electroless plating process. Based on these findings, flow sheets for recovering nickel from the spent baths are proposed.

• Applied Chemistry for Engineering
• /
• v.1 no.2
• /
• pp.240-248
• /
• 1990

The catalytic activity and selectivity of metal loaded H-mordenite for transalkylation of $C_9$ aromatics were studied in a continuous flow fixed bed reactor under high pressure. Nickel loaded H-mordenite(T-Ni) catalyst showed high activity and slow decay of activity. Molybdenum and nickel loaded H-mordenite(T-NiMo) catalyst also showed high activity and suppressed coking of hydrocarbons. The selectivity of xylene for T-Ni and T-NiMo catalysts decreased with temperature, but that for T catalyst(commercial grade) monotonically increased with temperature within the experimental range. The performance of T-Ni and T-NiMo catalysts was better than that of T catalyst in terms of initial activity and its decay. The addition of Mo improved slightly stability of T-Ni catalyst.