• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.262-262
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• 2012

A multi-purpose cyclotron, MC50 has been operated to provide multi-ions of proton, deuteron and alpha at Korea Institute of Radiological and Medical Sciences (KIRAMS). Neutron is also produced through the (p,n) nuclear process with a Be target. However, a wide spectrum of current of ions is requested by beam users for carrying their various application fields. Therefore a simulation study is requested on the design of an axial injection system for high current proton and alpha beam extraction for radio-isotope productions and scientific researches. The purpose of this study is seeking a relatively simple method for the MC50 having higher alpha beam capability and also improving proton and deuteron beams currently used. We are considering two possibilities to improve the internal ion source and to install a new external axial injection system. The external injection system will be consisted of an Einzel lens, a steering magnet, a buncher, and a glazer lens placed in front of an inflector, which is located at the center of the main magnet.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.309-314
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• 2002

The ablation dynamics and cluster formation of $C_n^+$ ions ejected from 355 nm laser ablation of a graphite target in vacuum are investigated using a reflectron time-of-flight (RTOF) mass spectrometer. At low laser fluence, odd-numbered cluster ions with $3{\leq}n{\leq}15$ are predominantly produced. Increasing the laser fluence shifts the maximum size distribution towards small cluster ions, implying the fragmentation of larger clusters within the hot plume. The temporal evolution of $C_n^+$ ions was measured by varying the delay time of the ion extraction pulse with respect to the laser irradiation, providing significant information on the characteristics of the ablated plume. Above a laser fluence of $0.2J/cm^2$ , large cluster ions ($n{\geq}30$) are produced at relatively long delay times, indicating that atoms or small carbon clusters aggregate during plume propagation. The dependence of the intensity of ablated $C_n^+$ ions on delay time after laser irradiation shows that the most probable velocity of each cluster ion decreases with cluster size.

• Food Science of Animal Resources
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• v.29 no.4
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• pp.482-486
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• 2009

The aim of this study was to optimize a simple, fast, and economical analysis procedure for the determination of 16 different pesticides in raw milk via GC/MSD. Analyses were performed via gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode (GC/MSD-SIM) using Pentachloronitrobenzene as the internal standard. The modified sample preparation methodology was based on the Pesticide Analytical Manual (PAM) of the FDA concerning fat extraction, ACN-ether partitioning, and clean-up of the Sep-Pak florisil cartridge. The modified methodology for the determination of the 16 pesticides was validated. The range of LOQs of the 16 pesticides was likely three times lower than their Maximum Residence Levels (MRLs). The recoveries of most of the pesticides were acceptable at the fortification levels of 0.5 and 1.0 ${\mu}g/mL$ and their RSD (%) level was less than 20%. None of the 16 pesticides were detected in the selected raw milk samples.

• Environmental Analysis Health and Toxicology
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• v.18 no.1
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• pp.45-55
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• 2003

The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrom-etry-selected ion monitoring (GC/MS-SIM) mode followed by two work-up methods for comparison; isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in paper samples were extracted with acetonitrile. Also, solid -phase extraction (SPE) with XAD -4 and subsequent conversion to isobutoxycarbonyl derivatives or tert.-butyldimethylsilyl derivatives for sensitive analysis with the selected ion-monitoring (SIM) mode. The SIM responses were linear with the correlation coefficient varying 0.9717 ∼ 0.9995 (isoBOC derivatization), and 0.9842 ∼ 0.9980 (TBDMS derivatization). The recoveries were 82.4 ∼ 108.8％) by area ratio of phenanthrene -d$\_$10/ vs bisphenol A-d$\^$l6/. (isoBOC derivatization and TBDMS derivatization) The range of concentrations was respectively, 0.95 ∼ 1.44 ng/g in 2,4-dichlorophenol, 1.01 ∼ 1.17 ng/g in t-butylphenol,2.17 ∼ 5.84 ng/g in pentachlorophenol, 12.68 ∼ 14.88 ng/g in nonylphenol and 30.84 ∼ 153.72 ng/g in bisphenol A.

• Environmental Engineering Research
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• v.12 no.3
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• pp.93-100
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• 2007

I improved an analytical method for determining trace amounts of eleven phenolic endocrine-disrupting chemicals (11 phenolic EOCs) in human urine. The 11 phenolic EOCs were subjected to hydrolysis and then to solid phase extraction with a XAD-4 column. Alkylphenols, chlorophenols, and bisphenol A in XAD-4 column were eluted with acetonitrile, and the eluate was concentrated under a nitrogen stream, and then tert-butyldimethylsilylation. Separation and determination were done by gas chromatography, using mass spectrometry operating in the selective ion monitoring mode for quantitation. For tert-butyldimethylsily (TBDMS) derivatization the recoveries were $91.2{\sim}125.9%$, the limits of quantitation (LOQ) for the 11 phenolic EOCs in the nanogram-per-milliliter range ($0.025{\sim}1.000\;ng/mL$) were thus achieved by using 1 mL of urine, and the SIM responses were linear with the correlation coefficient varying by $0.9300{\sim}0.9943$. Based on the results for urine samples from unexposed individuals, 4-tert-octylphenol and pentachlorophenol were detected in hydrolysed urine sample. Other alkylphenols, chlorophenols and bisphenol A were not detected.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2002.05a
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• pp.46-46
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• 2002

It is well known that thin film growth and surface morphology can be substantially modified by ion-bombardment during the deposition. This is particularly important in case of thin-film deposition at low temperatures where the film growth occurs under highly nonequilibrium conditions. An attractive way to promote crystalline growth and surface morphology is deposition of additional energy in to the surface of the growing film by bombardment with hyperthermal particles. We were deposited crystalline Ti and TiN thin films on Si substrate by magnetron sputtering method with grid. Its thin films were highly smoothed and dense as increasing grid bias. In order explore the benefits of a bombardment of the growing film with high energetic particles. Ti and TiN films were deposited on Si substrates by an unbalanced magnetron sputter source with attached grid assembly for energetic ion extraction. Also, we have studied the variation of the plasma states by Langmuir probe and Optical Emission Spectroscopy (OES). The epitaxial orientation. microstructual characteristics. electrical and surface properties of the films were analyzed by XRD. SEM. Four point probe and AFM.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2304-2308
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• 2010

A $LiNi_{0.8}Co_{0.15}Al_{0.05}O_2$ (LNCAO/C) active material composite cathode was coated with carbon. The conductive carbon coating was obtained by addition of surfactant during synthesis. The addition of surfactant led to the formation of an amorphous carbon coating layer on the pristine LNCAO surface. The layer of carbon coating was clearly detected by FE-TEM analysis. In electrochemical performance, although the LNCAO/C showed similar capacity at low C-rate conditions, the rate capability was improved by the form of the carbon coating at high current discharge state. After 40 cycles of charge-discharge processes, the capacity retention of LNCAO/C was better than that of LNCAO. The carbon coating is effectively protected the surface structure of the pristine LNCAO during Li insertion-extraction.

• Journal of the Korean Ceramic Society
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• v.21 no.1
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• pp.41-50
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• 1984

The ion-exchange porous glasses were prepared by heat treating and subsequently acid treating the (95-y) $SiO_2$.$yB_2O_3$.$5Na_2O+xAl_2O_3$ glasses with y=55, 45, 35, 25. mole% and x=0, 2, 5, 9 mole% It was then investigated how the cation exchange capacity was affected by the phase separation in these glasses. For that matter such quantities as alkali extraction amount pore volume and specific surface area of the glasses were measured. The phase separation in these glasses was in general suppressed by the addition of $Al_2O_3$ maximally around the composition of 5 mole% $Al_2O_3$ This may be because the micro-phase separation prevailed in the glass of that composition over the macro-phase separation increasing thereby the specific surface area as well as the residual amount Al of after acid-treatment and accordingly the cation exchange capacity. The maximum values of the cation exchange capacity was observed to be about 150meq/100g for the glasses of (40-50) $SiO_2$ (55~45)$yB_2O_3$. $5Na_2O+5Al_2O_3$.

• Resources Recycling
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• v.7 no.2
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• pp.9-15
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• 1998

Recovery af molybdenum in spent desulfuriring catalyst of petrochemical industries was studied from MfGnatc solulion which is a resultant of firstly remvercd vanadium by wet processes. In order to separate and recover molybdenum from upper mentioned rafinatz solution containing several mctal ions, such as molybdenum (1,100 ppm), vanadium (150 ppm), aluminium (19 ppm), and nickel (33 ppm), either adsorption technique by chelate resin or solvent extr~ction by tertiary amine as extractant was applied. In case of adsorption method, palyamine type chelate resin showed the highest selectivily far molybdenum ion up lo 60 ddm' of ancentration aftcr eluting with 3.0 rnolld~n' of NH,OH. On the othcr hand. molybdenum ion wa cffectlvely cxtractcd in Ule whole ranges of equilibrilrm pR by solvent extraction method with 10 ~01%-alamine 336 which was pretreated with 2N-HCI

• Analytical Science and Technology
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• v.15 no.5
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• pp.445-450
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• 2002

A sensitive gas chromatographic method has been established for the determination of total iodide in seawater as their volatile organic derivative. The method is based on the formation of 4-iodo-2,6-dimethylphenol with 2,6-dimethylphenol in matrix and a single-step extraction of the derivative with ethyl ether, which are then measured by gas chromatography-mass spectrometry (selected ion monitoring). Iodate in sea water was completely reduced to iodide with ascorbic acid and acetic acid. The detection limit was 0.1 ng/mL in seawater and the calibration curve showed good linearity with r=0.9997. The method was sensitive, reproducible and simple enough to permit the reliable routine analysis of total iodide in seawater. Total iodide in sea water was found about 30 ng/ml.