• Journal of the Korean Chemical Society
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• v.67 no.1
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• pp.64-67
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• 2023

• Progress in Medical Physics
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• v.19 no.4
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• pp.256-262
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• 2008

To evaluate the metabolic changes in normal adult brains due to alterations SENSE and NEX (number of excitation) by multi voxel MR Spectroscopy at 3.0 Tesla. The study group was composed of normal volunteers (5 men and 8 women) with a mean ($\pm$ standard deviation) age of 41 (${\pm}11.65$). Their ages ranged from 28 to 61 years. MR Spectroscopy was performed with a 3.0T Achieva Release Version 2.0 (Philips Medical System-Netherlands). The 8 channel head coil was employed for MRS acquisition. The 13 volunteers underwent multi voxel spectroscopy (MVS) and single voxel spectroscopy (SVS) on the thalamus area with normally gray matter. Spectral parameters were as follows: 15 mm of thickness; 230 mm of FOV (field of view); 2000 msecs of repetition time (TR); 288 msecs of echo time (TE); $110{\times}110$ mm of VOI (view of interest); $15{\times}15{\times}15$ mm of voxel size. Multi voxel spectral parameters were made using specially in alteration of SENSE factor (1~3) and 1~2 of NEX. All MRS data were processed by the jMRUI 3.0 Version. There was no significant difference in NAA/Cr and Cho/Cr ratio between MVS and SVS likewise the previous results by Ross and coworkers in 1994. In addition, despite the alterations of SENSE factor and NEX in MVS, the metabolite ratios were not changed (F-value : 1.37, D.F : 3, P-value : 0.262). However, line-width of NAA peak in MVS was 3 times bigger than that in SVS. In the present study, we demonstrated that the alterations of SENSE factor and NEX were not critically affective to the result of metabolic ratios in the normal brain tissue.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1393-1396
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• 2006

The 1+1 two-photon Resonant Enhanced Multiphoton Ionization (REMPI) spectra of 1,4-dichlorobenzene was obtained from 240 nm through to 250 nm on a laser mass spectrometer. Special care was taken to build up a heatable sample inlet system suitable for detecting a trace semi-volatile organic compound and reducing the memory effort on the inner wall of the inlet system. The detection limits of 1,4-dichlorobenzene in ppbV/V concentration range at certain wavelengths are presented.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.41-48
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• 2010

Non-contacting, laser-based resonant ultrasound spectroscopy (L-RUS) was applied to characterize the microstructure of a material. L-RUS is widely used by virtue of its many features. Firstly, L-RUS can be used to measure mechanical damping which related to the microstructural variations (grain boundary, grain size, precipitation, defects, dislocations etc). Secondly, L-RUS technology can be applied to various areas, such as the noncontact and nondestructive quality test for precision components as well as noncontact and nondestructive materials characterization. In addition, L-RUS technology can measure the whole field resonant frequency at once. In this paper, we evaluated material characteristics such as resonant frequency, nonlinear propagation characteristic through the development of Laser-Based Resonant Ultrasound spectroscopy (Laser-RUS) System for the detection of Micro Crack in Materials.

• Journal of Biosystems Engineering
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• v.40 no.4
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• pp.394-408
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• 2015

Spectroscopy is an emerging technology for the quality assessment of pharmaceutical samples, from tablet manufacturing to final quality assurance. The traditional methods for the quality management of pharmaceutical tablets are time consuming and destructive, while spectroscopic techniques allow rapid analysis in a non-destructive manner. The advantage of spectroscopy is that it collects both spatial and spectral information (called hyperspectral imaging), which is useful for the chemical imaging of pharmaceutical samples. These chemical images provide both qualitative and quantitative information on tablet samples. In the pharmaceutics, spectroscopic techniques are used for a variety of applications, such as analysis of the homogeneity of powder samples as well as determination of particle size, product composition, and the concentration, uniformity, and distribution of the active pharmaceutical ingredient in solid tablets. This review paper presents an introduction to the applications of various spectroscopic techniques such as hyperspectroscopy and vibrational spectroscopies (Raman spectroscopy, FT-NIR, and IR spectroscopy) for the quality and safety assessment of pharmaceutical solid dosage forms. In addition, various chemometric techniques that are highly essential for analyzing the spectroscopic data of pharmaceutical samples are also reviewed.

• KSTLE International Journal
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• v.1 no.2
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• pp.69-75
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• 2000

The paper compares topography, phase contrast and force spectroscopy in atomic force microscopy data for evaluating the microheterogeneity of surface layer. The worn surface of ion-plated TiN coating was measured using both a laboratory-built and a commercial AFM. The results of analysis revealed structural and micromechanical heterogeneity of the worn surfaces. We demonstrated that the phase image allows relatively qualitative estimation of elastic modulus of the sample surface. The tribolayer formed in the worn surface possessed much lower stiffness than the original coating. It is shown that the most stable phase imaging is provided with a stiff cantilever. In this case, phase contrast is well conditioned, first of all, by microheterogeneity of elastic properties of the investigated surfaces. In this study an attempt was also made to correlate the results of phase imaging with that of the farce spectroscopy. The joint analysis of information on the surface properties obtained by the phase imaging and quantitative data measured with the force spectroscopy methods allows a better understanding of the nature of the surface micromechanical heterogeneity.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.19-24
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• 2016

Along the few nano sizing dimensions of integrated circuit (IC) devices, acceptable interlayer material for design is inevitable. The interlayer which include dielectric, interconnect, barrier etc. needs to achieve not only electrical properties, but also mechanical properties for endure post manufacture process and prolonging life time. For developing intermetallic dielectric (IMD) the mechanical issues with post manufacturing processes were need to be solved. For analyzing specific structural problem and material properties Raman spectroscopy was performed for various researches in Si semiconductor based materials. As improve of the laser and charge-coupled device (CCD) technology the total effectiveness and reliability was enhanced. For thin film as IMD developed material could be analyzed by Raman spectroscopy, and diverse researches of developing method to analyze thin layer were comprehended. Also In-situ analysis of Raman spectroscopy is introduced for material forming research.

• Journal of the Korean Vacuum Society
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• v.12 no.S1
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• pp.70-73
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• 2003

Sum-frequency vibrational spectroscopy has recently been used to investigate the surface of the various polymers and was able to find the chemical compositions and structures specific to the surface. Here we report our studies on two specific polymer samples to demonstrate its capability. Polyimide thin films were made by spin coating on fused quartz and $CaF_2$ substrates. The sum-frequency signal originating mainly from the air/polymer interface showed markedly different spectra, indicating the structural change of the polymer surface depending on the underlying substrate. Various polyethylene surfaces were also investigated by sum-frequency vibrational spectroscopy. The surface of polyethylene samples in the CH-region showed different sum-frequency spectra, presumably due to the trace amount of additives having much higher concentration at the air/polymer interface. These examples demonstrate the surface and interface of the polymer could have different structure and chemical composition from those of a bulk, which can be studied effectively by surface nonlinear optical spectroscopy.

• Journal of the Korean Applied Science and Technology
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• v.28 no.3
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• pp.284-289
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• 2011

All spectroscopic methods used in this work indicate the instability of tungstophosphates in aqueous solutions and considerable dependence on pH with regard to the dominant species present in the solution. UV spectroscopy indicates that some changes occur in the system but they cannot be specified. IR spectroscopy gives more information on the identification of the dominant species as a function the pH of the solution. NMR spectroscopy provides unique data, which can be used for more accurate interpretation of changes in the solution of various pH values. In the case of aqueous solutions of tungstophosphates, the parent anion was present only in a very acidic solution of ca. pH 1. Some differences in interpretation of the molecular species present under various experimental conditions can be ascribed to some extent to the diversity of chemical shifts of NMR. Under physiological conditions attained with the addition of NaOH, tungstophosphates was dominantly present in the form of the lacunary monovacant anion.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.169-169
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• 2014

Interfacial electronic structure of bathocuproine and Al was investigated using in-situ photoemission spectroscopy and density functional theory (DFT) calculations. Bathocuproine is used for exciton blocking and electron transport material in organic photovoltaics and Al is typical cathode material. When thin thickness of Al was thermally evaporated on BCP, gap states were observed by ultraviolet photoemission spectroscopy. The closest gap state yielded below 0.3 eV from Fermi level. By x-ray photoemission spectroscopy, interaction of Al with nitrogen of BCP was observed. To understand the origin of gap states, DFT calculation was carried out and gap states was verified with successive calculation of interaction of Al and nitrogen of BCP. Furthermore, emergency of another state above Fermi level was observed. Remarkable reduction of electron injection barrier between Al and BCP, therefore, is possible.