• The Journal of the Petrological Society of Korea
• /
• v.21 no.2
• /
• pp.113-128
• /
• 2012

The chemical composition of the continental crust play an important role in understanding of crustal formation and evolution and quantifying other processes taking place within continental crust. We summarized geochemical data reported in the previous literature for the crustal rocks in the Korean Peninsula and divided their chemical composition into geologic time scale. In the variation diagram normalized by average composition of the upper crustal rocks, the geochemical characteristics of the upper crust during Triassic period is different from those of the upper crustal rocks after Jurassic period or before Precambrian. However, the geochemical characteristics of the Jurassic and Precambrian period are similar each other. Our summarized data indicate that the source material of Triassic upper crust may be different from that of Jurassic or Precambrian upper crust.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.4 no.2
• /
• pp.175-179
• /
• 2006

Welders are exposed to a number of hazards including metal fumes, toxic gases, electricity, heat, noise, and radiation such as ultraviolet and infrared light. We encountered a patient who developed non-cardiogenic pulmonary edema within a day after cutting copper pipe with an oxyethylene torch. The patient was a 26-year-old welder. He complained of dyspnea, generalized myalgia, and febrile sensation the following morning. The patient's chest X-ray and chest CT scan showed extensively distributed and ill-defined centrilobular nodules. Both his symptoms and chest X-ray abnormalities improved spontaneously. We attributed the patient's symptoms to non-cardiogenic pulmonary edema due to nitrogen dioxide, reasoning that: 1) the pipe consisted only of copper, according to material safety data sheet (MSDS); 2) a previous report in the literature demonstrated increased nitrogen dioxide levels under similar conditions; 3) the patient's clinical course and radiologic findings were very reminiscent of non-cardiogenic pulmonary edema following accidental exposure to nitrogen dioxide.

• Computers and Concrete
• /
• v.10 no.2
• /
• pp.135-147
• /
• 2012

At mesoscale, concrete is considered as a three-phase composite material consisting of the aggregate particles, the cement matrix and the interfacial transition zone (ITZ). The reconstruction of the internal structures for concrete composites requires the identification of the boundary of the aggregate particles and the cement matrix using digital imaging technology followed by post-processing through MATLAB. A parameter study covers the subsection transformation, median filter, and open and close operation of the digital image sample to obtain the optimal parameter for performing the image processing technology. The subsection transformation is performed using a grey histogram of the digital image samples with a threshold value of [120, 210] followed by median filtering with a $16{\times}16$ square module based on the dimensions of the aggregate particles and their internal impurity. We then select a "disk" tectonic structure with a specific radius, which performs open and close operations on the images. The edges of the aggregate particles (similar to the original digital images) are obtained using the canny edge detection method. The finite element model at mesoscale can be established using the proposed image processing technology. The location of the crack determined through the numerical method is identical to the experimental result, and the load-displacement curve determined through the numerical method is in close agreement with the experimental results. Comparisons of the numerical and experimental results show that the proposed image processing technology is highly effective in reconstructing the internal structures of concrete composites.

• Korean Journal of Medicinal Crop Science
• /
• v.28 no.5
• /
• pp.347-353
• /
• 2020

Background: Fermentation of medicinal plants increases their absorption rate and bioavailability in the body. Astragalus membranaceus has been used as a raw material, but research in its use as a food ingredient is lacking. Therefore, the purpose of this study was to identify the physicochemical characteristics and anti-inflammatory effect of fermented Astragalus membranaceus. Methods and Results: Astragalus roots were fermented using Aspergillus awamori for 4 days and their extracts prepared using hot water. The pH, total acidity (%), and reducing sugar (%) of the extracts were then investigated. The pH and total acidity decreased during fermentation. After fermentation, the pH and total acidity decreased, whereas the reducing sugar level increased. The active ingredients in fermented Astragalus were calycosin-7-O-ßd-glucoside, ononin, calycosin and formononetin. The calycosin contents was highest in the hot-water extracted samples fermented for 4 days. The other components were similar to those in control. Nitric oxide level was lower in the hot-water extracted samples fermented for 4 days than in lipopolysaccharide control group. The sample fermented for 4 days was confirmed to inhibit the production of tumor necrosis factor-α and interleukin-1β. Conclusions: Our results showed the physicochemical properties and anti-inflammatory effects of A. membranaceus after fermentation using Aspergillus awamori. These results indicated that fermented Astragalus membranaceus can be used as a functional food.

• Journal of the Mineralogical Society of Korea
• /
• v.27 no.4
• /
• pp.263-270
• /
• 2014

This paper was researched that provenance of the raw material for bronze relics excavated Cheonghaejin using the distribution of lead isotope ratio based on galena ores of South Korea. Also we want to make sure that the trace elements appearing as a by-product can be used as a secondary indicator for provenance research. In the case of the galena map of the East-North Asia (Mabuchi, 1985), data are plotted in China area. Therefore it is estimated that most bronzes were produced with lead ore from China. On the other hand, the same data are plotted in the Okcheon Metamorphic Belt and Yeongnam Massif of the galena map of South Korea (KOPLID, 2012). Also the contents of Ag and Sb are available as indicator due to separate ores from similar zone in lead isotope ratio.

• The Korea Journal of Herbology
• /
• v.21 no.2
• /
• pp.181-188
• /
• 2006

Objectives : Southern, northern, and wild types of Osterici Radix, and Notopterigii Rhizoma et Radix imported from China are circulated in Korea. Morphological identification was attempted by comparing external and internal forms of these materials. Methods : The slice of the tested material made by paraffin section technique was colored with Safranine Malachite Green contrast methods, and then observed and photographed by olymphus-BHT. Results : 1. Southern type of Osterici Radix has short rhizome and many small and long roots, while northern type of it is mostly composed of rhizomes with little small reds and sometimes looks like bamboo because of the extention of the parts between joints. 2. Parenchymal cell of southern type of Osterici Radix is filled with starch grain, while that of nothern type includes less starch grain with lamination crossed on its cell wall. 3. Surface of root and rhizome of wild Osterici Radix has some marks of fibrous root raised in the form of nodule, but cultivated Osterici Radix does not have this kind of marks. 4. Notopterigii Rhizoma et Radix is mostly composed of rhizomes, and its form is similar to that of a silkworm or joints of bamboo. Parenchymal cell is filled with starch grains, and lamination is crossed on its cell wall but not salient. Conclusion : Southern, northern, and wild types of Osterici Radix, and Notopterigii Rhizoma et Radix circulated in Korea can be easily identified because of their differences in their external and internal forms.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.35 no.1
• /
• pp.7-12
• /
• 2009

Purpose: Gelatin-hydroxyapatite nanocomposite is similar to inorganic nanostructure of bone. To make a scaffold with osteoinductivity, bone marrow derived stem cells from rabbit femur were impinged into the nanocomposite. This vitro study was to test osteogenic differentiation of the stem cells in the nanocomposite, which was made by authors. Material & Methods: Gel-HA nanocomposite with 10g of HA, 3 g of Gel has been made by co-precipitation process. Bone marrow was obtained from femur of New Zealand White rabbits and osteogenic differentiation was induced by culturing of the BMSCs in an osteogenic medium. The BMSCs were seeded into the Gel-HA nanocomposite scaffold using a stirring seeding method. The scaffolds with the cells were examined by scanning electron microscopy (SEM), colorimetry assay, biochemical assay with alkaline phosphatase (ALP) diagnostic kit, osteocalcin ELISA kit. Results: Gel-HA nanocomposite scaffolds were fabricated with relatively homogenous microscale pores ($20-40{\mu}m$). The BMSCs were obtained from bone marrow of rabbit femurs and confirmed with flow cytometry, Alizarin red staining. Attachment and proliferation of BMSCs in Gel-HA nanocomposite scaffold could be identified by SEM, ALP activity and osteocalcin content of BMSCs. Conclusion: The Gel-HA nanocomposite scaffold with micropores could be fabricated and could support BMSCs seeding, osteogenic differentiation.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.22 no.4
• /
• pp.253-259
• /
• 2018

Structure behaviors resulting from an earthquake are experimentally simulated mainly through a shaking table test. As for large-scale structures, however, size effects over a miniature may make it difficult to assess actual behaviors properly. To address this problem, research on the hybrid simulation is being conducted actively. This method is to implement numerical analysis on framework members that affect the general behavior of the structure dominantly through an actual scale experiment and on the rest parts by applying the substructuring technique. However, existing studies on hybrid simulation focus mainly on Slow experimental methods, which are disadvantageous in that it is unable to assess behaviors close to the actual level if material properties change depending on the speed or the influence of inertial force is significant. The present study aims to establish a Real-time hybrid simulation system capable of excitation based on the actual time history and to verify its performance and applicability. The hybrid simulation system built up in this study utilizes the ATS Compensator system, CR integrator, etc. in order to make the target displacement the same with the measured displacement on the basis of MATLAB/Simulink. The target structure was a 2-span bridge and an RC pier to support it was produced as an experimental model in order for the shaking table test and Slow and Real-time hybrid simulations. Behaviors that result from the earthquake of El Centro were examined, and the results were analyzed comparatively. In comparison with the results of the shaking table test, the Real-time hybrid simulation produced more similar maximum displacement and vibration behaviors than the Slow hybrid simulation. Hence, it is thought that the Real-time hybrid simulation proposed in this study can be utilized usefully in seismic capacity assessment of structural systems such as RC pier that are highly non-linear and time-dependent.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.11
• /
• pp.3275-3279
• /
• 2014

A mass balance method for purity assessment of thermolabile organic reference materials was established by combining several techniques, including liquid chromatography with UV/VIS detector (LC-UV), Karl-Fischer (K-F) Coulometry, and thermal gravimetric analysis (TGA). This method was applied to three fluoroquinolones like enrofloxacin, norfloxacin and ciprofloxacin. LC-UV was used to analyze structurally related organic impurities based on UV/VIS absorbance spectra obtained in combination with LC separation. For all three organic reference materials, the UV/VIS spectra of the separated impurities were similar to that of the major component of the corresponding materials. This indicates that the impurities are structurally related to the respective reference material sharing common chromophores. Impurities could be quantified by comparing their absorbances at the wavelength of maximum absorbance (${\lambda}_{max}$). The water contents of the reference materials were measured by K-F Coulometry by an oven-drying method. The total inorganic impurities contents were assayed from ash residues in TGA analysis with using air as a reagent gas. The final purities estimated from results of those analytical techniques were assigned as ($99.91{\pm}0.06$), ($97.09{\pm}0.17$) and ($91.85{\pm}0.17$)% (kg/kg) for enrofloxacin, norfloxacin and ciprofloxacin, respectively. The assigned final purities would be applied to the reference materials which will be used as calibrators for the certification of those compounds in matrix CRMs as starting points for the traceability of their certified values to SI units.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2007.09a
• /
• pp.665-678
• /
• 2007

It was applied the grouting method to fill densely the space between the bottom of the caisson and the ground with the grout mixture mixed with anti-washout admixture after locating accurately the precast caisson on three concrete landing pads but it is far different from a costly conventional method, which place concrete to build the foundation of reinforcement concrete on the spot after excavating inside of the temporary coffering wall for the bridge foundation in the sea. To verify the grouting method in advance, the full-scale trial test was performed twice on the land. After confirming the fluidity of material for the injection and some possible problems during construction and then enhancing the original design, the main process is ongoing and it has been finished 12 spots until now. The purpose of this study is to introduces for the first time in Korea the grouting method including the automatic and the manual monitoring process applied to, based on the main process of the caisson foundation finished already in the site. In a similar construction it is sincerely expected to be referred to in the future.