• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.7 s.250
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• pp.638-645
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• 2006

Recently, we reported that significant ion loss occurred prior to its detection in the conventional single particles mass spectrometry and more seriously the loss is ion-kinetic-energy-dependent. These lead to significant error in the measured chemical composition of nanoparticles. Here we attempted to design a novel ion optics that is capable of 100% detection of ions generated from single nanoparticle. Using a commercial software SIMION, we simulated the trajectories of ions launched at different speeds inside the previous single particle mass spectrometer We tested how affect changes in shape of repelling plate, adding Einzel lens, substitution of tube electrode between extraction and acceleration grids. As a results, we could find a best design by assembling the trials in the present condition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.11
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• pp.1007-1013
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• 1998

In this paper, the dielectric properties of fabricated Polyvinylidene fluoride(PVDF, $PVF_2$) thin film with substrate temperature from 30 to at vapor deposition. The dielectric properties of PVDF thin film had been studied in the frequency range from 10Hz to 4MHz at measuring temperature between 20 and $100^{/circ}C$. The anomalous increasing in dielectric constant and dielectric loss at low frequencies and high temperature was described for PVDF thin film containing ion impurities. In particularly, ion mobility of fabricated PVDF thin film at substrate temperature at $30^{/circ}C$ decrease from $2\times10^{-5}\;to\;3.07$\times10^{-7}cm^2/V.s$ On the other hand, ion density increase abruptly from 1.49\times$$10^{13}$ to $1.5\times$10^{16}$cm^{-3}$ In spite of decreasing of ion mobility, dielectric constants and dielectric loss for PVDF thin film increase rapidly with decreasing frequency and high temperature. It was concluded that the dielectric constants and dielectric loss was related to ion density than to ion mobility at low frequency and high temperatures.

• Analytical Science and Technology
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• v.14 no.5
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• pp.384-391
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• 2001

In this study, a new quantitative analytical method has been developed for the rapid determination of acylcarnitines and amino acids in human blood using electrospray ionization / tandem mass spectrometry (ESI-MS/MS). Acylarmitines and amino acids were analyzed by tandem mass spectrometry after conversion to their butylesters through treatment with 3N butanolic hydrogen chloride. Acylcrnitines were analyzed using precursor 85 ion scan and alanine, valine, leucine/isoleucine, methionine, phenylalanine, tyrosine, aspartic acid and glutamic acid were analyzed using neutral loss 102 scan, ornitine and citrulline were analyzed neutral loss 119 scan, glycine was analyzed using neutral loss 56 scan, arginine was analyzed using neutral loss 161 scan and argininosuccinic acid was analyzed product ion 459 scan. This method reduced sample preparation time compared to that with conventional amino acid analyzer and liquid chromatography, with high sensitivity and good reproducibility.

• Journal of the Korean institute of surface engineering
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• v.50 no.6
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• pp.504-509
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• 2017

In order to improve corrosion resistance for cast stainless steel in seawater, the characteristics of corrosion resistance after plasma ion nitriding was investigated. Plasma ion nitriding process was conducted in a mixture of nitrogen of 25% and hydrogen of 75% at substrate temperature ranging from 350 to $500^{\circ}C$ for 10 hours using pulsed-DC glow discharge plasma with working pressure of 250 Pa in vacuum condition. Corrosion tests were carried out for as-received and plasma ion nitrided specimens. The corrosion characteristics were investigated by measurement of weight loss and observation of surface morphology. In anodic polarization experiment, relatively less damage depth and weight loss were presented at a nitrided temperature of $400^{\circ}C$, attributing to the formation of S-phase.

• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.596-598
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• 2006

• Journal of the Korean Society of Industry Convergence
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• v.19 no.4
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• pp.198-205
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• 2016

For the study on the ion exchange of nickel hexacyanoferrate(NiHCNFe) electrode with the several cations, the film of hexacyanoferrate was prepared on the bare nickel surface by the electrochemical and chemical methods in the solution composed with 5mM K3Fe(CN)6 and 100mM KNO3. To compare the capability of the ion exchange of NiHCNFe film electrode, the repeated cyclic voltammograms were measured in the 0.5M cation nitrate solutions at $25^{\circ}C$ and pH7. It was found that the capacity of the electrochemically derivatized NiHCNFe reduced in the rate of 0.5~0.7%/cycle and was nearly exhausted at the 150th potential cycle. Better result was obtained from that the capacity loss of the chemically assembled NiHCNFe was less than 0.02%/cycle for 5,000cycles. Furthermore, the residual capacity was more than 30% at the 5,000th cycle.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.469-472
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• 2000

Replacement policy of a degradation of system is investigated by incorporating the loss function defined by the deviation of the value of quality characteristic from its target value, which determines the loss cost . Two cost minimization problems are formulated : 1)determination of an optimal inspection period given the state for the replacement and 2)determination of an optimal state for replacement under fixed inspect ion period. Simulation analysis is performed to observe the variation of total cost with respect to the variation of the parameters of loss function, inspection cost, respectively. As a result, parameters of loss function are seen to be the most sensitive to the total cost. On the contrary, inspect ion cost is observed to be insensitive.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.721-724
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• 2014

We have explored the potential energy surface for the dissociation of the pyridazine molecular ion using G3 model calculations. The pathways have been obtained for the formation of five possible $C_4H_4^{+{\bullet}}$ isomers by the loss of $N_2$ and the consecutive $H^{\bullet}$ loss. It is predicted that the methylenecyclopropene radical cation is the predominant product in the loss of $N_2$, which is formed via the allenylcarbene radical cation, and $CH_2=C-C{\equiv}CH^+$ is the predominant product in the consecutive $H^{\bullet}$ loss.

• Journal of the Korean Society for Heat Treatment
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• v.18 no.6
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• pp.369-374
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• 2005

Nitrogen ion implantation in Nimonic 80A using plasma immersion ion implantation (PIII) was investigated at a pulse voltage of -60 kV and ion dose of $3{\times}10^{17}{\sharp}/cm^2$, $6{\times}10^{17}{\sharp}/cm^2$, $12{\times}10^{17}{\sharp}/cm^2$. PIII is an effective technology to improve the surface hardness and wear resistance of materials. And also this technology is not limited by the shape and size of materials. PIII would be a promising technique in the future. Surface hardness and wear resistance of the $N^+$ ion implanted Nimonic 80A were increased with the increase in the incident ion dose. The surface hardness of the untreated Nimonic 80A is 420 Hv, the hardness of implanted Nimonic 80A is 1050 Hv at $N^+$ ion dose of $12{\times}10^{17}{\sharp}/cm^2$. The wear loss of the untreated is 82.5 mg, the wear loss of the implanted is 0.004g at $N^+$ ion dose of $12{\times}10^{17}{\sharp}/cm^2$. The $Cr_2N$ is detected on the surface of the implanted Nimonic 80A by XRD analysis.

• Journal of the Korean Society of Industry Convergence
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• v.19 no.4
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• pp.176-184
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• 2016

Electrochemical ion exchange method is expected to be one of the most acceptable techniques for the separation of radioactive cations from nuclear wastewater. In this study a thin film of hexacyanoferrate on nickel surface was derivatized chemically in an aqueous potassium-ferricyanide solution. Electrochemical redox behavior of the nickel hexacyanoferrate(NiHCNFe) film electrode was investigated with the use of cyclic voltammetry potentiostated from -100 to 800 mV versus SCE. The electro-reduction characteristics of the NiHCNFe film were examined in the cobalt solutions. The NiHCNFe ion exchanger was more useful at lower concentration, lower temperature, and pH7 of the cobalt solution. The capacity loss of NiHCNFe was 0.018%/cycle that was less than the average loss of 2~3%/cycle of the convective organic exchanger. The 45~55% of the initial cobalt ions was electro-deposited on the NiHCNFe by using continuous recirculating reactor system. As a result, it was found that the electroactive NiHCNFe films showed better performance than the organic resins for the separation of cobalt ion from the aqueous solutions.