• Analytical Science and Technology
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• v.13 no.6
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• pp.781-788
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• 2000

Tellurium in simulated nuclear spent fuels (SIMFUEL) has been determined by hydride generation-inductively coupled plasma atomic emission spectrometry (HG-ICP-AES). Parameters such as concentrations of HCl and $NaBH_4$, flow rate of HCl and $NaBH_4$ were optimized and then the effects of U, Mo, Pd, Rh and Ru on the Te intensity were investigated. A thiourea as a masking agent was used to eliminate or minimize such interferences specially caused by palladium. Tellurium was measured by HG-ICP-AES and ICP-MS after separation of tellurium from SIMFUEL with cation exchange chromatography. The relative deviation between direct measurement and separation method was less than 6% based on the data by ICP-MS.

• Journal of Space Technology and Applications
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• v.3 no.3
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• pp.239-256
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• 2023

The Earth's ionosphere is an area where part of the upper atmosphere is ionized and exists in a plasma state that affects radio waves. It is a field that has been studied for a long time as it directly affects real life in relation to communications. Depending on the altitude, it is divided into D, E, and F layers depending on the main ions that make up the electron density. The density of the neutral atmosphere is very large compared to the electron density, so it should be described as plasma taking that effect into account. It is an area where influences from outside the ionosphere are directly reflected, starting from the sun and extending to the earth's surface, and is a field that involves complex and diverse areas of research. In this paper, we explain the process by which the Earth's upper atmosphere is ionized to form the ionosphere and introduce the characteristics of the ionosphere at low and mid-latitudes. In addition, we introduce the research that domestic researchers have participated in related to the ionosphere to date and hope that it will be used to promote exchange in the field of ionospheric research in the future.

• Journal of the Korean Institute of Gas
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• v.9 no.4 s.29
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• pp.17-25
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• 2005

The dealuminated and alkali/alkaline-earth metal exchanged Y-zeolites were prepared as a catalyst. Elemental compositions and structures of the prepared catalysts were analyzed by the various spectroscopic techniques such as inductively coupled plasma-atomic emission spectroscopy(ICP-AES), X-ray fluorescence(XRF) and X-ray diffraction(XRD), and the desorption behaviors of adsorbed species on the catalyst surfaces were investigated via NO-TPD experiment. Comparing with the composition of the starting material of NaY zeolite, the magnitudes of Si/Al ratio in catalytic materials were increased after dealumination. The Si/Al ratio of catalytic materials after dealumination followed by Cs and Ba cation exchange were additionally decreased. Dealumination to catalysts induced a destruction of basic frame due to a detachment of aluminum, which results in reducing framework structure, while increasing non-framework structure. This phenomenon becomes more serious with increasing time of steam treatment and even more significant for the cation exchanged catalysts. In NO-TPD experiments, the desorption peaks of NO which indicates an activity point of catalysts shifted to the low temperature region after dealumination and cation exchange. The desorption peaks of the NO-TPD profiles taken after steam treatment also shifted to the low temperature region as the steam treatment time increased. In dealuminated and cation exchanged Y-zeolites, the catalytic activities were more influenced by exchanged cation and the formation of non-framework structure.

• Journal of Life Science
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• v.33 no.2
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• pp.208-215
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• 2023

In recent decades, the field of aging research has progressed from the genetic and cellular levels to in vivo models of blood exchange. Since genes capable of extending the lifespan in C. elegance have been reported, various potential target molecules have been discovered through genomics, proteomics, metabolomics, and transcriptomics. Accordingly, research on the interactions between target molecules has also been increasing. The parabiosis method, in which two experimental animals are surgically combined, was introduced, and a factor that could reverse the aging phenomenon was discovered using this method. The parabiosis method is used to find more accurate and effective aging-reversal factors that could exist in young blood. As more new evidence has been revealed, the parabiosis method has established a new paradigm for aging research. Moreover, a device capable of exchanging blood elaborately in laboratory animals was published in 2022 and presented new results necessary for aging reversal. Since GDF11, was reported, many other anti-aging candidates that are soluble factors in blood, such as β2m, TIMP2, VCAM1, Gpld1, and clusterin, have been discovered. In addition, mcicroglia cells and neuroinflammation have been directly proven to be aging factors. These latest research results were obtained by parabiosis, the newly designed device for plasmapheresis, and injecting young blood or conditioned blood methods. In this review, we discuss the latest research results using the device and young blood administration in old mice.

• International Journal of Vascular Biomedical Engineering
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• v.2 no.2
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• pp.16-26
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• 2004

The object of this study is to develop a mathematical model of the hemodialysis system including the mechanism of solute kinetics, water exchange and also cardiovascular dynamics. The cardiovascular system model used in this study simulates the short-term transient and steady-state hemodynamic responses such as hypotension and disequilibrium syndrome (which are main complications to hemodialysis patients) during hemodialysis. It consists of a 12 lumped-parameter representation of the cardiovascular circulation connected to set-point models of the arterial baroreflexes, a kinetic model (hemodialysis system model) with 3 compartmental body fluids and 2 compartmental solutes. We formulate mathematically this model in terms of an electric analog model. All resistors and most capacitors are assumed to be linear. The control mechanisms are mediated by the information detected from arterial pressoreceptors, and they work on systemic arterial resistance, heart rate, and systemic venous unstressed volume. The hemodialysis model includes the dynamics of urea, creatinine, sodium and potassium in the intracellular and extracellular pools as well as fluid balance equations for the intracellular, interstitial, and plasma volumes. Model parameters are largely based on literature values. We have presented the results on the simulations performed by changing some model parameters with respect to their basal values. In each case, the percentage changes of each compartmental pressure, heart rate (HR), total systemic resistance (TSR), ventricular compliance, zero pressure filling volume and solute concentration profiles are represented during hemodialysis.

• Corrosion Science and Technology
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• v.9 no.3
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• pp.129-136
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• 2010

The corrosion behaviors of 316L stainless steel were investigated in simulated anodic and cathodic environments for proton exchange membrane fuel cell (PEMFC) by using electrochemical measurement techniques. Interfacial contact resistance(ICR) between the stainless steel and gas diffusion layer(GDL) was also measured. The possibility of 316L was evaluated as a substitute material for the graphite bipolar plate of PEMFC. The value of ICR decreased with an increase in compaction stress(20 N/$cm^2$~220 N/$cm^2$) showing the higher values than the required value in PEMFC condition. Although 316L was spontaneously passivated in simulated cathodic environment, its passive state was unstable in simulated anodic environment. Potentiostatic and electrochemical impedance spectroscopy (EIS) measurement results showed that the corrosion resistance in cathodic condition was higher and more stable than that in anodic condition. Field emission scanning electron microscopy (FE-SEM), and inductively coupled plasma(ICP) were used to analyze the surface morphology and the metal ion concentration in electrolytes.

• Analytical Science and Technology
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• v.10 no.5
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• pp.307-314
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• 1997

Inductively coupled plasma atomic emission spectrometry(ICP/AES) was used for the determination of uranium and thorium in geological materials. Samples were predecomposed by mixed acid digestion technique. The separation of the uranium and thorium was achieved by systematic solvent extraction with TTA(thenoyltrifluoroacetone) and TOA (tri-n-octylamine) and back extraction into HCl. The results for standard rock sample, NIST SRM 278, showed a good agreement with those certified from NIST as well as found values by other non-destructive techniques. Additional purification for extracted portions was carried out by anion exchange chromatography for measurement of several natural radioisotopes of uranium and thorium by alpha spectrometry.

• Fisheries and Aquatic Sciences
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• v.7 no.3
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• pp.99-108
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• 2004

Vitellogenin (VTG) was purified from serum of $estradiol-l7{\beta}-treated rockfish$(Sebastes schlegeli) by precipitation with $EDTA-Mg^{2+}$ and ammonium sulfate and two step chromatography (anion exchange chromatography and gel permeation chromatography) was performed on FPLC system. Rockfish VTG (rfVTG) was characterized and its properties were determined. The monomers have apparent, molecular mass of about 188 kDa as indicated by SDS-PAGE. Amino acid composition analysis of rfVTG was similar to VTG from other oviparous teleosts. Cysteine and lysine were present at relatively high level. Leucine was present at relatively lower level than in other species. The N-terminal amino acid sequence was evaluated to identify rfVTG. Western blot analysis using an antibody against the purified VTG showed that the antibody reacted with both plasma of $estradiol-l7{\beta}-treated rockfish$ treated male and purified VTG, whereas there was no reaction with male serum of the control. An ELISA was developed using monoclonal and polyclonal antibodies against rfVTG. The assay range was 3.2 ng/mL and 1,000 ng/mL and the value of the intra and inter assay variations were within $9.7{\%}$ and $11.2{\%}$, respectively. Recovery rate was $96.8{\%}$. The sandwich ELISA could be useful for the detection of VTG and could be good for screening of estrogenic compounds.

• Journal of Chest Surgery
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• v.23 no.6
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• pp.1049-1056
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• 1990

The OXYREX hollow fiber membrane oxygenator developed by joint work of KIST and Green Cross Medical company has been evaluated by experimental investigation and clinical application, In this oxygenator gas exchanges occur through small pores of 0.1pm size which are distributed on 70% of surface of polypropylene hollow fiber. The Oxyrex membrane oxygenator consists of 36 thousand hollow fibers and it has 3.3m2 of gas exchange surface. The Oxyrex membrane oxygenator has unique blood flow path: blood enters the oxygenator passes between the hollow fibers and exits through outlet ports, that provides low transmembrane pressure drop. In the animal experiment and in vitro investigations of Oxyrex oxygenator, it showed low transmembrane pressure difference, effective heat exchanger performance, stable gas transfer function and less blood trauma. The Oxyrex oxygenator been used from March, 1990, to October, 1990, in 40 patients undergoing open heart operations. In the clinical applications of Oxyrex, adequate oxygenation[PaO2, 283$\pm$70mmHg] and carbon dioxide removal[PaCO2, 27\ulcorner6mmHg]were maintained under the condition of FiO2: below 0.6, Hct; 25%, perfusion flow; 2.4 L/min, gas flow: 2.1 L/min. During maximum 365 minutes of cardiopulmonary bypass[CPB] time period, the Oxyrex oxygenator maintained stable condition of PaO2, PaCO2 respectively and it also kept low plasma hemoglobin level. The complement proteins C3 and CH50 were not significantly changed pre to post CPB. There were no complications related to the oxygenator during and after the CPB.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.201-204
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• 2007

A novel self-humidifying composite membrane for the proton exchange membrane fuel cell (PEMFC) at low humidity condition was developed. The $Pt/TiO_2 catalyst particles were synthesized via supercritical impregnation methods. Pt precursor was dissolved in supercritical carbon dioxide and impregnated onto $TiO_2$ particles. Pt precursors were platinum(II) acetylacetonate, Dimethyl(1,5-cyclooctadiene) platinum(II) and we controlled the ratio of Pt to $TiO_2$ The impregnated Pt precursor was converted to $TiO_2$ supported Pt nanoparticle under various reducing conditions. $TiO_2$ catalyst particles were dispersed uniformly into the Nafion solution, and then $Pt/TiO_2/Nafion$composite membrane was prepared using solution-cast method. The size, dispersion and content of the platinum had been characterized with Transmission Electron Micrograph (TEM), X-ray diffract ion (XRD) and Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP-AES). The cell performance with the self-humidifying composite membrane was compared with a recast Nafion membrane under both humidified and dry conditions at 65 $^{\circ}C$.