In situ mass spectrometry of glucose decomposition under hydrothermal reactions

Pattasuda Duangkaew,Shuhei Inoue,Tsunehiro Aki,Yutaka Nakashimada,Yoshiko Okamura,Takahisa Tajima,Yukihiko Matsumura 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.5

We designed an in situ mass spectrometry (in situ MS) analysis method and developed to identify the products of glucose decomposition under hydrothermal condition for the first time. The in situ MS analysis was performed by coupling a tubular batch reactor with a quadrupole mass analyzer via custom-built connection fittings. The products of glucose decomposition were investigated by in situ MS, mass spectrometry of cold effluent, and high-performance liquid chromatography (HPLC) analysis of cold effluent and the results were compared. At 140 oC, in situ MS and mass spectrometry of cold effluent showed that the decomposition of glucose does not proceed; this was confirmed by comparison with the mass spectral database for glucose. At 180 oC or higher, a clear base fragmentation peak of 5-hydroxymethylfurfural (5-HMF) at position m/z 97 and that of furfural at m/z 96, formic acid (m/z=46) and levulinic acid (m/z=116) were observed by mass spectrometry. No levulinic acid or furfural was observed through conventional HPLC analysis under any condition; only glucose, formic acid, and 5-HMF could be detected. The effectiveness of in situ MS analysis is clear, compared to mass spectrometry analysis of cold effluent and HPLC analysis.

Importance of Precision Analysis in Steel Production

Suzuki, K. 대한금속재료학회 2003 METALS AND MATERIALS International Vol.9 No.6

This brief review introduces developments in analytical technologies that result from cooperation between people engaged in analysis and those engaged in steelmaking. In addition, the basic principles of solute distribution during solidification of steel melt and various types of segregations are outlined for the benefit of young engineers who perform analyses. Recent topics and future trends in steel analysis are also discussed to improve the understanding of the importance of precision analysis.

Kainic acid 투여에 의한 흰쥐 뇌에서의 heat shock protein 70 유전자의 발현

윤주원,강윤희,전용혁,박선화,김현 대한해부학회 1995 Anatomy & Cell Biology Vol.28 No.1

현장시험을 통해 지반의 비선형 전단탄성계수를 산정하기 위한 역해석방법의 개발

안재훈,Ahn. Jae-Hun 한국방재학회 2008 한국방재학회논문집 Vol.8 No.3

지반의 비선형 전단탄성계수를 결정하기 위한 현장시험에서는, 먼저 지반과 원형기초에 지오폰을 설치하고, 기초에 대형 진동발생장치를 이용하여 진동하중을 가한다. 이 때, 지오폰으로부터 지반과 기초의 거동을 측정하고, 본 거동을 분석하여 전단탄성 계수와 해당 전단변형률을 결정할 수 있다. 본 논문에서는 현장시험결과로부터 지반의 선형, 비선형 전단탄성계수를 결정하기위한 역해석 과정의 필요성과 그 개발에 초점을 맞추었다. 제안된 역해석 과정은 비선형 최소자승법을 근간으로 하며, 거동이 계측되지 않는 곳의 지반의 비선형성을 고려하기 위하여 이중 반복루프를 사용하였다. 역해석 과정의 적용성을 검토하기 위하여 일련의 수치해석을 수행하였으며, 또한 역해석 적용의 예제를 보였다. 제안된 방법은 현장지반의 전단탄성계수 분포의 변화가 극심하지 않은 경우에는 전반적으로 우수한 적용성을 보이지만, 해석대상 지반의 전단파속도 분포가 역해석의 정확성에 영향을 수 있으므로, 예비 역해석을 통해 산출될 오차를 정량화 하는 것이 필요하다. The large scale shaker can be employed to measure linear and nonlinear shear moduli of soils in situ as a function of shear strain. The method involves applying dynamic loads on a surface foundation measuring the dynamic response of the soil mass beneath the foundation with embedded instrumentation. This paper focuses on the development of a framework of the inverse analysis for the interpretation of test data to estimate linear and nonlinear shear moduli of soils along with the necessity of the inverse analysis. The suggested framework is based on the nonlinear least squares but it uses two iterative loops to account for the nonlinear behavior of soil that sensors are not located. The validity of the suggested inversion framework is tested through a series of numerical parametric studies. An example use of the suggested inversion framework is also shown. Because the field condition may affect the accuracy of suggested method, it is important to conduct a preliminary inverse analysis to quantify the discrepancy between the estimated modulus and the baseline.

Development and characterization of tubular direct methanol fuel cells for use in <i>in situ</i> NMR analysis

Um, Myung Sup,Han, Oc Hee,Lee, Juhee,Song, Kwang Ho,Lee, Hwa Young,Ha, Heung Yong Elsevier 2012 International journal of hydrogen energy Vol.37 No.12

<P><B>Abstract</B></P><P>The present study developed a tubular direct methanol fuel cell (tubular DMFC) for use in <I>in situ</I> Nuclear Magnetic Resonance (NMR) that could monitor various electrochemical reactions in real time. The tubular DMFC was fabricated in such a way as to prevent corrosion of cell components and to facilitate a supply of the reactants and removal of the products. The cell showed improved performance and durability sufficient for its use in an <I>in situ</I> NMR test, but problems with rapid performance decay persisted. Detailed reasons for the performance degradation were investigated through rigorous analytical work using various techniques. The tubular DMFC was also installed in an NMR probe to test signal sensitivity and resolution of <SUP>2</SUP>D NMR spectra for deuterated methanol (CD<SUB>3</SUB>OH) and deuterated water (D<SUB>2</SUB>O). The spectral resolutions of both species were high, and their signal intensities were strong enough to realize an acceptable spectra.</P> <P><B>Highlights</B></P><P>► A tubular DMFC has been developed for use in <I>in situ</I> NMR. ► Performance and durability of the DMFC were improved by employing corrosion-resistant cell components. ► The reasons for the performance decay were analyzed by using various analytical tools. ► The <I>in situ</I> NMR with a tubular DMFC presented a high resolution for CD<SUB>3</SUB>OH and D<SUB>2</SUB>O.</P>

Quantitative Analysis of Sr and Cs in LiCl-KCl Molten Salt by Laser-Induced Breakdown Spectroscopy (LIBS)

Hyeongbin Kim,Yunu Lee,Wonseok Yang,Sungyeol Choi 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

During electrorefining, fission products, such as Sr and Cs, accumulate in a eutectic LiCl-KCl molten salt and degrade the efficiency of the separation process by generating high heat and decreasing uranium capture. Thus, the removal of the fission products from the molten salt bath is essential for reusing the bath, thereby reducing the additional nuclear waste. While many studies focus on techniques for selective separation of fission products, there are few studies on processing monitoring of those techniques. In-situ monitoring can be used to evaluate separation techniques and determine the integrity of the bath. In this study, laser-induced breakdown spectroscopy (LIBS) was selected as the monitoring technique to measure concentrations of Sr and Cs in 550°C LiCl-KCl molten salt. A laser spectroscopic setup for analyzing high-temperature molten salts in an inert atmosphere was established by coupling an optical path with a glove box. An air blower was installed between the sample and lenses to avoid liquid splashes on surrounding optical products caused by laser-liquid interaction. Before LIBS measurements, experimental parameters such as laser pulse energy, delay time, and gate width were optimized for each element to get the highest signal-to-noise ratio of characteristic elemental peaks. LIBS spectra were recorded with the optimized conditions from LiCl-KCl samples, including individual elements in a wide concentration range. Then, the limit of detections (LODs) for Sr and Cs were calculated using calibration curves, which have high linearity with low errors. In addition to the univariate analysis, partial least-squares regression (PLSR) was employed on the data plots to obtain calibration models for better quantitative analysis. The developed models show high performances with the regression coefficient R2 close to one and root-mean-square error close to zero. After the individual element analysis, the same process was performed on samples where Sr and Cs were dissolved in molten salt simultaneously. The results also show low-ppm LODs and an excellent fitted regression model. This study illustrates the feasibility of applying LIBS to process monitoring in pyroprocessing to minimize nuclear waste. Furthermore, this high-sensitive spectroscopic system is expected to be used for coolant monitoring in advanced reactors such as molten salt reactors.

PGC-Enriched miRNAs Control Germ Cell Development

Bhin, Jinhyuk,Jeong, Hoe-Su,Kim, Jong Soo,Shin, Jeong Oh,Hong, Ki Sung,Jung, Han-Sung,Kim, Changhoon,Hwang, Daehee,Kim, Kye-Seong Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.10

Non-coding microRNAs (miRNAs) regulate the translation of target messenger RNAs (mRNAs) involved in the growth and development of a variety of cells, including primordial germ cells (PGCs) which play an essential role in germ cell development. However, the target mRNAs and the regulatory networks influenced by miRNAs in PGCs remain unclear. Here, we demonstrate a novel miRNAs control PGC development through targeting mRNAs involved in various cellular pathways. We reveal the PGC-enriched expression patterns of nine miRNAs, including miR-10b, -18a, -93, -106b, -126-3p, -127, -181a, -181b, and -301, using miRNA expression analysis along with mRNA microarray analysis in PGCs, embryonic gonads, and postnatal testes. These miRNAs are highly expressed in PGCs, as demonstrated by Northern blotting, miRNA in situ hybridization assay, and miRNA qPCR analysis. This integrative study utilizing mRNA microarray analysis and miRNA target prediction demonstrates the regulatory networks through which these miRNAs regulate their potential target genes during PGC development. The elucidated networks of miRNAs disclose a coordinated molecular mechanism by which these miRNAs regulate distinct cellular pathways in PGCs that determine germ cell development.

PGC-Enriched miRNAs Control Germ Cell Development

빈진혁,김계성,정호수,김종수,신정오,홍기성,정한성,김창훈,황대희 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.10

Non-coding microRNAs (miRNAs) regulate the translation of target messenger RNAs (mRNAs) involved in the growth and development of a variety of cells, including primordial germ cells (PGCs) which play an essential role in germ cell development. However, the target mRNAs and the regulatory networks influenced by miRNAs in PGCs remain unclear. Here, we demonstrate a novel miRNAs control PGC development through targeting mRNAs involved in various cellular pathways. We reveal the PGC-enriched expression patterns of nine miRNAs, including miR-10b, -18a, -93, - 106b, -126-3p, -127, -181a, -181b, and -301, using miRNA expression analysis along with mRNA microarray analysis in PGCs, embryonic gonads, and postnatal testes. These miRNAs are highly expressed in PGCs, as demonstrated by Northern blotting, miRNA in situ hybridization assay, and miRNA qPCR analysis. This integrative study utilizing mRNA microarray analysis and miRNA target prediction demonstrates the regulatory networks through which these miRNAs regulate their potential target genes during PGC development. The elucidated networks of miRNAs disclose a coordinated molecular mechanism by which these miRNAs regulate distinct cellular pathways in PGCs that determine germ cell development.

Multi-Dimensional Liquid Phase TEM for Studying Energ Materials

박정원 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Most of heterogeneous catalyst synthesis and their uses are developed empirically with a limited mechanistic understanding. Liquid cell TEM (LTEM) has been introduced recently for in-situ study of chemical reactions occurring in liquid. Liquid cells allow an opportunity to utilize high spatial and temporal resolution of TEM in studying reactions of colloidal nanoparticles. Achieving sub-nm spatial resolution by adjusting the thicknesses of window materials and the encapsulated liquid, important steps in growth trajectories of different types of heterogeneous catalysts have been directly observed at high-resolution of TEM. We also develop an analysis method for resolving the 3D atomic structure of individual particles in liquid. Obtained 3D density maps unveil structural features of heterogeneous catalysts that have been either underestimated or unattainable in conventional analysis. Applying in situ biasing TEM in studying Li-air battery system will be also introduced.

Visualization and prediction of supercritical CO₂ distribution in sandstones during drainage: An <i>in situ</i> synchrotron X-ray micro-computed tomography study

Voltolini, Marco,Kwon, Tae-Hyuk,Ajo-Franklin, Jonathan ELSEVIER SCIENCE B.V., AMSTERDAM 2017 INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Vol.66 No.-

<P><B>Abstract</B></P> <P>Pore-scale distribution of supercritical CO<SUB>2</SUB> (scCO<SUB>2</SUB>) exerts significant control on a variety of key hydrologic as well as geochemical processes, including residual trapping and dissolution. Despite such importance, only a small number of experiments have directly characterized the three-dimensional distribution of scCO<SUB>2</SUB> in geologic materials during the invasion (drainage) process. We present a study which couples dynamic high-resolution synchrotron X-ray micro-computed tomography imaging of a scCO<SUB>2</SUB>/brine system at <I>in situ</I> pressure/temperature conditions with quantitative pore-scale modeling to allow direct validation of a pore-scale description of scCO<SUB>2</SUB> distribution. The experiment combines high-speed synchrotron radiography with tomography to characterize the brine saturated sample, the scCO<SUB>2</SUB> breakthrough process, and the partially saturated state of a sandstone sample from the Domengine Formation, a regionally extensive unit within the Sacramento Basin (California, USA). The availability of a 3D dataset allowed us to examine correlations between grains and pores morphometric parameters and the actual distribution of scCO<SUB>2</SUB> in the sample, including the examination of the role of small-scale sedimentary structure on CO<SUB>2</SUB> distribution. The segmented scCO<SUB>2</SUB>/brine volume was also used to validate a simple computational model based on the local thickness concept, able to accurately simulate the distribution of scCO<SUB>2</SUB> after drainage. The same method was also used to simulate Hg capillary pressure curves with satisfactory results when compared to the measured ones. This predictive approach, requiring only a tomographic scan of the dry sample, proved to be an effective route for studying processes related to CO<SUB>2</SUB> invasion structure in geological samples at the pore scale.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Experimental visualization of the 3D distribution of scCO<SUB>2</SUB> at <I>in situ</I> conditions via synchrotron X-ray micro tomography. </LI> <LI> Quantitative morphometric analysis of the data to find the governing geometrical parameters in the distribution of the scCO<SUB>2</SUB>. </LI> <LI> An effective 2-phase modeling approach capable of accurately replicating the experimental results has been developed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>