• Electrical & Electronic Materials
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• v.9 no.7
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• pp.719-726
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• 1996

DLTS measurements were performed to study the annealing induced changes of the trap centers in MOV and to shed more light on the stability mechanism of the MOV. Two electron traps, Ec-0.26[eV] and Ec-(O.2-0.3)[eV], were observed in the unannealed samples in large quantities(7-9 X 1014[CM 3]), whereas the three electron traps Ec-0.17 [eV], Ec-0.26[eV] and Ec-(O.2-0.3)[eV] were observed far less in the annealed samples. The minima in the Ec-0.26[eV] trap density, coupled with the presented results that unannealed devices are unstable whereas 600.deg. C annealed devices are most stable, suggests that the instability of the MOV under long term electrical stressing is related to the Ec-0.26[eV] trap. This results support that the ion migration model for the device instability where the Ec-0.26[eV] defects may be the interstitial zinc or the migrating ions. The interstitial zinc originated as a result of the nonstoichiometric nature of ZnO might cause the degradation of the I-V characteristics of the MOV with long term electrical stressing.

• Mass Spectrometry Letters
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• v.3 no.2
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• pp.29-38
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• 2012

A new approach of volatile compounds analysis is proposed using a linear ion trap Orbitrap mass spectrometer coupled with gas chromatography through an atmospheric pressure photoionization interface. In the proposed GC-HRMS/MS approach, direct chemical composition analysis is made for the precursor ions in high resolution MS spectra and the structural identifications were made through the database search of high quality MS/MS spectra. Successful analysis of a complex perfume sample was demonstrated and compared with GC-EI-Q and GC-EI-TOF. The current approach is complementary to conventional GC-EI-MS analysis and can identify low abundance co-eluting compounds. Toluene co-sprayed as a dopant through API probe significantly enhanced ionization of certain compounds and reduced oxidation during the ionization.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.113-118
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• 2003

An investigation has been carried out on collision-induced dissociation (CID) in the development of an analytical protocol for the determination of polycyclic aromatic hydrocarbons (PARs) by ion trap tandem mass spectrometry. Two different considerations were used to choose the optimal CID conditions for complex matrix environmental samples, namely, to determine the highest signal-to-noise (SIN) ratio and the other to eliminate the background interferences originated from complex matrix samples. The PAR content of agricultural soil was measured to estimate overall distribution of PAR in throughout the country, we collected and analyzed 226 soil samples from paddy and upland soil. The average content of total PAR in all samples was 236 ${\mu}g$ $kg^{-1}$, and the range was from 23.3 to 2, 834 ${\mu}g$ $kg^{-1}$. The overall distribution of PAR was found to be closely related to the pollution sources, the size of city and the type of industry.

• Analytical Science and Technology
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• v.11 no.3
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• pp.194-201
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• 1998

The formaldehyde vapor produced from wood and steel furniture was absorbed in distilled water and derivatized with acetylacetone and determined by UV-visible spectrophotometry. Variation in HCHO emission with time was monitored at room temperature. The emission of volatile compounds from wood, wood-based and steel-based materials was investigated in a 50 mL glass vial. The concentration of the gases emitted in a glass vial was determined by ion-trap GC-MS.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1647-1650
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• 2002

• Proceedings of the PSK Conference
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• 2002.04a
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• pp.219.3-219.3
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• 2002

• Analytical Science and Technology
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• v.14 no.5
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• pp.392-399
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• 2001

The analysis of n-butylbenzene and 1,2-dibromo-3-chloropropane (DBCP) as volatile organic compounds in biota samples was performed by gas chromatography/mass spectrometry-selected ion monitoring mode. The target compounds, n-butylbenzene and DBCP, in biota samples were extracted by headspace solid phase microextraction (SPME) with $100{\mu}m$ polydimethyl siloxane (PDMS) fiber and purge & trap method. The extraction recoveries of these compounds obtained by SPME was 85.8% for n-butylbenzene and 92.4% for DBCP, respectively. Each value of method detection limit were $0.15{\mu}g/kg$ and $0.05{\mu}g/kg$, respectively. While in the case of purge & trap method, the extraction recovery was 115.2% for n-butylbenzene, 80.9% for DBCP and method detection limit were $0.04{\mu}g/kg$ and $0.70{\mu}g/kg$, respectively. The extraction yields and detection limits of these compounds obtained by purge & trap were equivalent to those by SPME.

• YAKHAK HOEJI
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• v.54 no.3
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• pp.157-163
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• 2010

A high-performance liquid chromatography (HPLC) with DAD detector and electrospray ionization mass spectrometry (ESI-MS) was established for the simultaneous determination of coniferin (1), loganic acid (2), demethylsecologanol (3), sweroside (4) and loganin (5) from caulis Lonicera joponica. The optimal chromatographic conditions were obtained on an ODS column ($5{\mu}m$, $4.6{\times}150mm$) with the column temperature $35^{\circ}C$. The mobile phase was composed of (A) water with 0.1% formic acid and (B) methanol with 0.1% formic acid using a gradient elution, the flow rate was 0.3 ml/min. Detection wavelength was set at 254 nm. All calibration curves showed good linear regression ($r^2$>0.998) within test ranges. The developed method provided satisfactory precision and accuracy with overall intra-day and interday variations of 0.16~3.28% and 0.14~1.99%, respectively, and the overall recoveries of 99.39~105.89% for the five compounds analyzed. The verified method was successfully applied to quantitative determination of the two types (phenolic compounds and iridoids) of bioactive compounds in 24 commercial caulis L. japonica samples from different markets in Korea and China. The analytical results demonstrated that the contents of the five analytes vary significantly with sources.

• Transactions on Electrical and Electronic Materials
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• v.16 no.4
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• pp.187-189
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• 2015

A charge-trap flash (CTF) thin film transistor (TFT) memory is proposed at a low-temperature process (≤ 450℃). The memory cell consists of a sputtered oxide-nitride-oxide (ONO) gate dielectric and Schottky barrier (SB) source/drain (S/D) junctions using nickel silicide. These components enable the ultra-low-temperature process to be successfully achieved with the ONO gate stacks that have a substrate temperature of room temperature and S/D junctions that have an annealing temperature of 200℃. The silicidation process was optimized by measuring the electrical characteristics of the Ni-silicided Schottky diodes. As a result, the Ion/Ioff current ratio is about 1.4×10⁵ and the subthreshold swing and field effect mobility are 0.42 V/dec and 14 cm²/V·s at a drain voltage of −1 V, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.7 no.2
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• pp.59-65
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• 1982

In this paper, the CdS single crystal, which was grown as piper-polish method, was Ion-bombarded with Sb and In, and the thermally stimulated current of the spot that was Ionbombarded was measured. In the sample which was individually bombarded by Sb and In, the over-lapping peak was found, this over lapping peak was separated, by the method of thermal cleaning, showing the trap levels of 0.25(eV) and 0.31(eV) at the temperature of 147(K) and 181(K). While the spot is being cooled down and excited with photolight at the same time, the trap level 0.25(eV) disappeared and the new trap level of 0.85(eV) appeared. It can be said that the better photo-conductive crystals, the T.S.C is better measured.