• Journal of the Korean Vacuum Society
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• v.6 no.4
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• pp.298-307
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• 1997

TDS(Thermal Desorption Spectroscopy)system, for diagnosis of CRT manufacturing process, was designed and constructed. Outgassings and thermal desorptions from the part or materials of CRT can be measured and analysed with this system at various temperatures. The system is consisted of 3 parts, vacuum chamber and pumping system with variable conductance, sample heating stages & their controller, and outgassing measurement devices, like as ion gauge or quadrupole mass spectrometer. The ultimate pressure of the system was under $1{\times}10^{-7}$ Pa. With the variable conductance system, the effective pumping speed of the chamber could be controlled from sub l/s to 100 l/s. The effective pumping speed values were determined by dynamic flow measurement principle. The temperatures and ramp rate of sample were controlled by tungsten heater and PID controller up to 600℃ within ±1℃ difference to setting value. Ion gauge & QMS were calibrated for quantitative measurements. Some examples of TDS measurement data and application on the CRT process analysis were shown.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.190-201
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• 2001

Isotope Dilution Mass Spectrometry(IDMS) is one of the analytical method which uses enriched isotope spikes and analyzes the abundance of element by comparison of the spectrum between spiked mass and non-spike mass. Especially, the Thermal Ion Mass Spectrometry with isotope dilution technique (in general ID-TIMS) is the most accurate method of the chemical analysis, which enables us to obtain the data better than 1% in accuracy and precision. In IDMS, enriched isotope spike is one of the most important factor in order to obtain the best data. For rare earth elements, in general, a mixture of /sup 138/La, /sup 142/Ce, /sup 145/Nd, /sup 149/Sm, /sup 151/Sm, /sup 151/Eu, /sup 157/Gd, /sup 163/Dy, /sup 167/Er, /sup 171/Yb, and /sup 176/Lu is used as composite spike. IDMS is very useful in geochronology and REE geochemistry. Especially, it is very effective in studying the “tetrad effect” of rare earth elements in natural samples.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.3 s.22
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• pp.83-91
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• 2005

Pyrolysis-mass spectrometry has been used to characterize the 17 biological materials including bacteria and proteins. In this study, an in situ thermal-hydrolysis methylation(THM) procedure using tetramethylammonium hydroxide(TMAH) was employed. The biological materials are ionized using chemical ionization(CI) method with ethanol by ion trap mass spectrometer(ITMS), which attached with our own made pyrolyzer module, and then their pyrolysis mass spectra were obtained. The major distinct characteristic peaks were selected from all the range of mass spectra, and analyzed using principal component analysis(PCA) method to assess the classification/identification possibility of biological materials.

• Bulletin of the Korean Chemical Society
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• v.19 no.8
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• pp.830-835
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• 1998

The characteristics of the ablation plume generated by 532 nm Nd: YAG laser irradiation of a Pb(Zr0.52Ti0.48)O3 (PZT) target have been investigated using a pulsed-field time-of-flight mass spectrometer (TOFMS). The relative abundance of O+, Ti+, Zr+, Pb+, TiO+, and ZrO+ ions has been measured and discussed. TiO+ and ZrO+ ions were also found to be particularly stable within the laser ablation plasma with respect to PbO+ species. The behavior of the temporal distributions of each ionic species was studied as a function of the delay time between the laser shot and the ion extraction pulse. The most probable velocity of each ablated ion is estimated to be Vmp=1.1-1.6x 105 cm/s at a laser fluence of 1.2 J/cm2, which is typically employed for the thin film deposition of PZT. The TOF distribution of Ti+ and Zr+ ions shows a trimodal distribution with one fast and two slow velocity components. The fast velocity component (6.8x 10' cm/s) appears to consist of directly ablated species via nonthermal process. The second component, originated from the thermal evaporation process, has a characteristic velocity of 1.4-1.6 x 105 cm/s. The slowest component (1.2 x 105 cm/s) is composed of a dissociation product formed from the corresponding oxide ion.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.121-124
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• 2008

This paper presents the fabrication and field emission of carbon nanotube field emitters for a micro mass spectrometer. The carbon nanotube is an adequate material as a field emitter since it has good characteristics. We have successfully fabricated a diode field emitter and a triode field emitter. Each field emitter has been constructed using several micromachining processes and a thermal CVD process. In the case of the diode field emitter, to increase the electric field, the carbon nanotubes are selectively grown on the patterned nickel catalyst layer. The electron current of the diode field emitter is 73.2 ${\mu}A$ when the anode voltage is 1100V. That of the triode field emitter is 3.4 pA when the anode voltage is 1000V.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.5
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• pp.461-476
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• 2014

Continuous Water-Soluble Organic Carbons (WSOC) by the Particle Into Liquid Sampler - Total Organic Carbon (PILS-TOC) analyzer were measured at the Seoul intensive monitoring site from June 17 through July 5 in 2014. In addition, the 24 hour integrated PM2.5 collected by Teflon and Quartz filters were analyzed for water soluble ions by Ion chromatography (IC), WSOC by TOC from water extracts, organic carbon (OC), elemental carbon (EC) by carbon analyzer using the thermal optical transmittance (TOT) method, and mass fragment ions (m/z) related to alkanes and PAHs (Poly Aromatic Hydrocarbons) by Gas Chromatography-Mass Spectrometer-Thermal Desorption (GC/MS-TD). Based on the statistical analysis, four different Carbonaceous Thermal Distributions (CTDs) from OCEC thermal-gram were identified. This study discusses the primary and secondary sources of WSOC based on the Classified CTD, organic mass fragments, and diurnal patterns of WSOC. The results provide knowledge regarding the origins of WSOC and their behaviors.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.3 s.18
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• pp.110-121
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• 2004

Pyrolysis-mass spectrometry, incorporating an in situ thermal hydrolysis and methylation(THM) step, has been used to study biological materials for bacteria, toxin and virus. Newly developed pyrolyzer was used to decompose biological materials, and tetramethylammonium hydroxide(TMAH) was used as a methylation reagent. Chemical ionization(CI) using ethanol and ion trap mass spectrometer(ITMS) were used to ionize and analyze of pyrolysis components, respectively. Analytical characteristics of bacteria (including spore), virus and toxin were analyzed. Also acquisition and interpretation of mass spectra as biomarkers for classification/identification of biological material s were explained.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.4
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• pp.263-270
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• 2020

In this study, the physical mechanism and diffusion effects in aluminium implanted silicon was investigated. For fabricating power semiconductor devices, an aluminum implantation can be used as an emitter and a long drift region in a power diode, transistor, and thyristor. Thermal treatment with O₂ gas exhibited to a remarkably deeper profile than inert gas with N₂ in the depth of junction structure. The redistribution of aluminum implanted through via thermal annealing exhibited oxidation-enhanced diffusion in comparison with inert gas atmosphere. To investigate doping distribution for implantation and diffusion experiments, spreading resistance and secondary ion mass spectrometer tools were used for the measurements. For the deep-junction structure of these experiments, aluminum implantation and diffusion exhibited a junction depth around 20 ㎛ for the fabrication of power silicon devices.

• Asian Journal of Atmospheric Environment
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• v.6 no.1
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• pp.53-66
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• 2012

A comparison of analytical approaches for Levoglucosan ($C_6H_{10}O_5$, commonly formed from the pyrolysis of carbohydrates such as cellulose) and used for a molecular marker in biomass burning is made between the four different analytical systems. 1) Spectrothermography technique as the evaluation of thermograms of carbon using Elemental Carbon & Organic Carbon Analyzer, 2) mass spectrometry technique using Gas Chromatography/mass spectrometer (GC/MS), 3) Aerosol Mass Spectrometer (AMS) for the identification of the particle size distribution and chemical composition, and 4) two dimensional Gas Chromatography with Time of Flight mass spectrometry (GC${\times}$GC-TOFMS) for defining the signature of Levoglucosan in terms of chemical analytical process. First, a Spectrothermography, which is defined as the graphical representation of the carbon, can be measured as a function of temperature during the thermal separation process and spectrothermographic analysis. GC/MS can detect mass fragment ions of Levoglucosan characterized by its base peak at m/z 60, 73 in mass fragment-grams by methylation and m/z 217, 204 by trimethylsilylderivatives (TMS-derivatives). AMS can be used to analyze the base peak at m/z 60.021, 73.029 in mass fragment-grams with a multiple-peak Gaussian curve fit algorithm. In the analysis of TMS derivatives by GC${\times}$GC-TOFMS, it can detect m/z 73 as the base ion for the identification of Levoglucosan. It can also observe m/z 217 and 204 with existence of m/z 333. Although the ratios of m/z 217 and m/z 204 to the base ion (m/z 73) in the mass spectrum of GC${\times}$GC-TOFMS lower than those of GC/MS, Levoglucosan can be separated and characterized from D (-) +Ribose in the mixture of sugar compounds. At last, the environmental significance of Levoglucosan will be discussed with respect to the health effect to offer important opportunities for clinical and potential epidemiological research for reducing incidence of cardiovascular and respiratory diseases.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.496-498
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• 2005

We reported that high dielectric hafnium oxide nano-film deposited by thermal atomic layer deposition on the poly-silicon film (poly-Si). The poly -Si film was produced by plasma enhanced chemical vapor deposition and excimer laser annealing. We used the hafniu m chloride ($HfCl_4$) and water as the precursors and analyzed the hafnium oxide film by transmission electron microscope and secondary ion mass spectrometer. Hafnium oxide produced by the ALD method showed very good coverage on the rough surface of poly-Si film. While deposited with 200 cycles, these hafnium oxide films revealed a relatively smooth surface and good uniformity, but the cumulative roughness produced by the incomplete reaction was apparent when the amount of deposition cycle increased to 600 cycles.