• KSTLE International Journal
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• v.3 no.1
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• pp.12-16
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• 2002

Micro/nano tribological and water wetting characteristics of ion beam treated PTFE (polytetrafluoroethylene) surfaces were experimentally studied. The ion beam treatment was performed with a hollow cathode ion gun at different argon ion dose conditions in a vacuum chamber to modify the topography of PTFE surface. Micro/nano tribological characteristics, water wetting angles and roughness were measured with a micro tribe tester, SPM (scanning probe microscope), contact anglemeter and profilometer, respectively. Results showed that surface roughness increased with the argon ion dose. Water wetting angle of the ion beam treated samples increased with the ion dose, so the surface shows an ultra-hydrophobic nature. Micro-adhesion and micro-friction depend on the wetting characteristics of the PTFE samples. However, nano-tribological characteristics showed different results. The scale effect of surface topography on tribological characteristics was discussed. Also, the water wetting characteristics of modified PTFE samples were discussed in terms of the surface topographic characteristics.

• Korean Journal of Materials Research
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• v.15 no.1
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• pp.54-60
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• 2005

Recently a lots of problems have observed in high densified and high integrated electronic components. One of them is ion migration phenomena, which induce the electrical short of electrical circuit. ion migration phenomena has been observed in the field of exposing the specific environment and using for a long tin e. This study was evaluated the generation time of ion migration and was investigated properly test method through water drop test and high temperature high humidity test. Also we observed direct causes and confirmed generation mechanism of dendritic growth as we reproduced the ion migration phenomena. We utilized PCB(printed circuit board) having a comb pattern as follows 0.5, 1.0, 2.0 mm pattern distance. Cu, SnPb and Au were electroplated on the comb pattern. 6.5 V and 15 V were applied in the comb pattern and then we measured the electrical short time causing by ion migration. In these results, we examined a difference of ion migration time depending on pattern materials, applied voltage and pattern spacing of PCB conductor.

• Polymer(Korea)
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• v.31 no.4
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• pp.315-321
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• 2007

Aminated PONF-9-GMA ion exchange fabrics were synthesized by radiation induced graft copolymerization. Hybrid ion exchange fabrics combined with aminated PONF-g-GMA fabrics and anionic ion exchange resin were also fabricated by hot melt adhesion method and then their adsorption properties were investigated. Ion exchange capacity of the hybrid ion exchange fabrics was higher than ion exchange fabric and was lower than bead resin. The maximum value was 4.18 meq/g. Adsorption breakthrough time for vanadium of the hybrid ion exchange fabric was 550 min, which was faster than bead resin but slower than fibrous ion exchanger. The Breakthrough time of the hybrid ion exchange fabrics gets longer with increasing pH. The initial breakthrough time occurred around 400 min with increasing vanadium concentration.

• Journal of Surface Science and Engineering
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• v.39 no.3
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• pp.105-109
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• 2006

The effects of negative carbon ion beam energy on the bonding configuration, hardness and surface roughness of DLC film prepared by a direct metal ion beam deposition system were investigated. As the negative carbon ion beam energy increased from 25 to 150 eV, the $sp^3$ fraction of DLC films was increased from 32 to 67%, while the surface roughness was decreased. The films prepared at 150 eV showed the more flat surface morphology of the film than that of the film prepared under another ion beam energy conditions. Surface roughness of DLC film varied from 0.62 to 0.22 nm with depositing carbon ion beam energy. Surface nano-hardness increased from 12 to 57 Gpa when increasing the negative carbon ion beam energy from 25 to 150 eV, and then decreased when increasing the ion beam energy from 150 to 200 eV.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.220-220
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• 1999

In plasma source ion implantation, the target is immersed in the plasma and repetitively biased by negative high voltage pulses to implant the extracted ions from plasma into the surface of the target material. In this way, the problems of line-of-sight implantation in ion-beam ion implantation technique can be effectively solved. In addition, the high dose rate and simplicity of the equipment enable the ion implantation a commercially affordable process. In this work, plasma source ion implantation technique was used to improve the wear resistance of Co-cemented WC. which has been extensively used for high speed tools. Nitrogen and carbon ions were implanted using the pulse bias of -602kV, 25 sec and at various implantation conditions. The implanted samples were examined using scanning Auger electron spectroscopy and XPS to investigate the depth distributions of implanted ions and to reveal the chemical state change due to the ion implantation. The implanted ions were found to have penetrated to the depth of 3000$\AA$. The wear resistance of the implanted samples was measured using pin-on-disc wear tester and the wear tracks were examined with alpha-step profilometer.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1465-1470
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• 2004

A short and efficient synthesis, solvent extraction and potentiometric measurements of new thiazole-containing naphtho-crown ethers are reported. The naphthalene moiety enhances the ammonium ion selectivity over potassium ion. The selectivity of ${NH_4}^+/K^+$ follows the trend $3\;{\approx}\;2\;>\;1$, indicating that the differences in conformational changes of 2 and 3 in forming ammonium complexes affect little on the resulting ammonium/potassium extraction selectivity ratio. The ammonium ion-selective electrodes were prepared with noctylphenyl ether plasticized poly(vinyl chloride) membranes containing 1-4 the effect of one naphthalene unit introduced on either right (2) or left (3) side of thiazolo-crown ether on their potentiometric properties (e.g., ammonium ion selectivity over other cations, response slopes, and detection limits) were not apparent. However, the ammonium ion selectivity of 1, 2 and 3 over other alkali metal and alkaline earth metal cations is 10-100 times higher than that of nonactin.

• Journal of Environmental Science International
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• v.21 no.12
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• pp.1449-1454
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• 2012

The ion selective microelectrodes (ISME) have been applied to observe the continuous profiles of NO3-N and NH4-N in bulk solutions or biofilms. In order to evaluate the performance and applicability of ion concentration measuring system, the characteristics, such as slope of calibration curve, detection limit and potentiometric selectivity coefficient were investigated. The slopes of calibration curve showed high degree of correspondence for each target ion concentrations. And the detection limits of nitrate and ammonia ion selective microelectrode were 10-4.7 M and 10-4.4 M, respectively. These ion selective microelectrodes were proved that their own performance could be maintained for 16 days after making. NO3-N and NH4-N selective microelectrodes were also adapted to detect the continuous ion profiles of cilia media packed MLE (Modified Ludzack-Ettinger) process. And the monitored nitrate and ammonia ion profiles with the ion selective microelectrode were stable and well corresponded to the results with conventional ion chromatograph. However, the electric potential was unstable until 8 hr because of the unknown noise. The tip shape and performance of the ion selective microelectrode was stably kept over 2 days continuous monitoring.

• Journal of the Korean Ceramic Society
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• v.33 no.2
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• pp.242-250
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• 1996

Glasses of Na2O-Al2O3-SiO2 system were prepared and ion-exchange characteristics change of properties and bactericidal effects by Na+↔Ag+ ion exchange were studied. Parent glasses with three compositions of varying Na2O in the 20~30 wt% were ion-exchanged in the molten salt of 2 mol% AgNO3+98 mol% NaNO3 at 320~36$0^{\circ}C$ for 15~16min. Amount of ion exchange and penetration depth of Ag+ ion increased with Na2O content in the parent glass ion exchange temperature and time. After ion exchange densities and Vickers hardness of the glasses increased and the glasses showed yellow-brown color and as amount of ion exchange increased the color turned deep because partial reduction and agglomeration of Ag+ into Ag0 results in absorption of visible light. After ion exchange chemical durability of the glass to wter was enhanced compara-bly that weight loss and change of surface of the glass were not found for the leaching test in 5$0^{\circ}C$ K.I water for 240hrs. Bactericidal effect of ion exchanged glass on Staphylococcus aureus and E. coli was determined by microorganism test and bactericidal effect increased with amount of ion exchange and incubation time.

• Analytical Science and Technology
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• v.6 no.1
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• pp.47-55
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• 1993

The quantitative determination of trace cyanide ion in the presence of sulfide ion has been studied by addition of cupric ion using differential pulse Cathodic Stripping Voltammetry. The detection limit of cyanide ion in the presence of $5.0*10^{-5}M$ sulfide ion and $1.0*10^{-3}M$ cupric ion was $2.0*10^{-7}M$ in KCI-Phosphate buffer(pH=7.0) at accumulation potential -0.30V and accumulation time 3.0 min.

• Journal of the Korean Society for Heat Treatment
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• v.24 no.2
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• pp.77-81
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• 2011

Aluminum nitride (AlN) thin films were prepared by using nitrogen ion beam assisted reactive radio frequency (RF) magnetron sputtering on the glass substrates without intentional substrate heating. After deposition, the effect of nitrogen ion beam energy on the structural and optical properties of AlN films were investigated by x-ray diffraction (XRD), atomic force microscope (AFM) and UV-Vis. spectrophotometer, respectively. AlN films deposited with $N^+$ ion irradiation at 100 eV show the higher (002) peak intensity in XRD pattern than other films. It means that $N^+$ ion energy of 100 eV is the favorable condition for low temperature crystallization. AFM images also show that surface average roughness is increased from 1.5 to 9.6 nm with $N^+$ ion energy in this study. In an optical observation, AlN films which deposited by $N^+$ ion beam energy of 100 eV show the higher transmittance than that of the films prepared with the other $N^+$ ion beam conditions.