• Journal of Korean Society for Atmospheric Environment
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• 제16권E호
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• pp.29-38
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• 2000

For the detailed characterization of atmospheric aerosol, the analysis of single particle is highly valuable. In this study, to investigate the characteristics of single Asian dust storm particles, scanning electron microscope(SEM) coupled with and energy dispersive X-ray microanalyzer(EDX) and micro-PIXE were applied. Sampling was performed at Kyoto University located in Kyoto, Japan, in spring of 1999. Mass concentration during Asian dust storm events was higher roughly 3∼5 times than measured in the season of the highest concentration. Single particles were generally sharp-edged and irregular in shape and contained mostly crustal elements. Significant amount of S in coarse fraction was detected in individual particles. A large particles in coarse fraction existed as the mixture of soil components and S. A good agreement between the result of SEM-EDX analysis and that iof micro-PIXE analysis was obtained in this study.

• 대한화학회지
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• 제60권5호
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• pp.317-320
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• 2016

Efficient copper removal from water was achieved by using surface modified silica spheres with 3-mercaptopropyltrimethoxysilane (MPTMS) using base catalyst. The surface modification of silica spheres was performed by hydrolysis and condensation reactions of the MPTMS. The characteristic infrared absorption peaks at 2929, 1454, and 1343 cm⁻¹ represent the −CH₂ stretching vibration, asymmetric deformation, and deformation, respectively. The absorption peaks at 2580 and 693 cm⁻¹ corresponding the −SH stretching vibration and the C-S stretching vibration indicate the incorporation of MPTMS to the surface of silica spheres. Field emission scanning electron microscope (FESEM) image of the surface modified silica sphere (SMSS) shows nano-particles of MPTMS on the surface of silica spheres. High concentration of copper solution (1000 ppm) was used to test the copper removal efficiency and uptake capacity. The FESEM image of SMSS treated with the copper solution shows large number of copper lumps on the surface of SMSS. The copper concentration drastically decreased with increasing the amount of SMSS. The residual copper concentrations were analyzed using inductively coupled plasma mass spectrometer. The copper removal efficiency and uptake capacity with 1000 ppm of copper solution were 99.99 % and 125 mg/g, respectively.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.45-46
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• 2003

A process control system has been developed for measurement and characterization of the nanofiber web qualities. The nano-fiber information system (NAFIS) developed consists of a measurement device and an analysis algorithm, which are a microscope-laser sensor fusion system and a process information system, respectively. It has been found that NAFIS is so successful in detecting irregularities of pore and diameter that the resulting product has been quitely under control even at the high production rate. Pore distribution, fiber diameter and mass uniformity have been readily measured and analyzed by integrating the non-contact measurement technology and the random function-based time domain signal/image processing algorithm. Qualifies of the nano-fiber webs have been revealed in a way that the statistical parameters for the characteristics above are calculated and stored in a certain interval along with the time-specific information. Quality matrix, scale of homogeneity is easily obtained through the easy-to-use GUI information. Finally, ANFIS has been evaluated both for the real-time measurement and analysis, and for the process monitoring.

• 한국안전학회지
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• 제32권3호
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• pp.8-14
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• 2017

This study examined the combustion and thermal characteristics of imported woods for building materials in Korea. Wooden specimens were confirmed by a cone calorimeter according to the KS F ISO 5660-1 standard. The combustion properties of the wooden specimens were measured in terms of the heat release rate (HRR), total heat released (THR), mass lose rate (MLR), and ignition time (time to ignition; TTI). The optical microscope was used for determine the anatomical characteristics of wood pit and structure. Also, the thermal properties were measured by thermogravimetric analysis (TGA) to determine the thermal stability of wooden specimens. The result of this experiment would be useful for fundamentals of guiding the combustion properties and thermal stability using wood application.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2611-2616
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• 2011

We studied the physical properties of the mercaptopyruvic-acid layer formed on gold surfaces, which has the interactions with the titanium dioxide surface for design of gold- titanium dioxide distribution. Surface force measurements were performed, using the atomic force microscope (AFM), between the surfaces as a function of the salt concentration and pH value. The forces were analyzed with the DLVO (Derjaguin-Landau-Verwey-Overbeek) theory, to evaluate the potential and charge density of the surfaces quantitatively for each salt concentration and each pH value. The difference in the properties reflected the effect of the isoelectric point on the surface forces. The forces were interpreted for the evaluation with the law of mass action and the ionizable groups on the surface. The salt concentration dependence of the surface properties, found from the measurement at pH 8.0, was consistent with the prediction from the law. It was found that the mercaptopyruvic-acid layer had higher values for the surface charge densities and potentials than the titanium dioxide surfaces at pH 8, which may be attributed to the ionized-functional-groups of the mercaptopyruvic-acid layer.

• E2M - 전기 전자와 첨단 소재
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• 제8권3호
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• pp.298-305
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• 1995

Copper-indium diselenide, $CuInSe_2$, thin films have been fabricated by selenizing Cu/In stacked layers with different sputtered Cu/(Cu+ln) mole ratios at 450.deg. C for 1hr on alumina substrates. The selenium source was selenium vapor. Microstructure, crystallization, and composition of the selenized $CuInSe_2$ films were examined by using scanning electron microscope, X-ray diffraction, Auger electron spectroscopy, and secondary ion mass spectrometry. Electrical resistivity and hall effects were also measured to investigate the electrical properties. As the sputtered Cu/(Cu+In) mole ratio of In/Cu layer increased, the amounts of void and CuSe phase in the selenized films increased but the composition of $CuInSe_2$ phase was the same regardless of the sputtered mole ratio. Comparing the electrical properties of $CuInSe_2$ thin film before and after the chemical etching, it was seen that the electrical resistivity, carrier concentration, and carrier mobility of the selenized films were affected by the amount of CuSe phase which seemed to increase primarily the hole concentration of the selenized films.

• 한국세라믹학회지
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• 제34권5호
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• pp.483-490
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• 1997

Al2O3/metal composites were fabricated by oxidation and reaction of molten Al-alloy into two types of commercial Al2O3-SiO2 fibrous insulation board. The growth rate, composition and microstructure of these materials were described. An AlZnMg(7075) alloy was selected as a parent alloy. Mixed polycrystalline fiber and glass phase fiber were used as a filler. The growth surface of an alloy was covered with and without SiO2. SiO2 powder was employed as a surface dopant to aid initial oxidation of Al-alloy. Al-alloy, SiO2, fiber block and growth inhibitor CaSiO3 were packed sequentially in a alumina crucible and oxidized in air at temperature range 90$0^{\circ}C$ to 120$0^{\circ}C$. The growth rate of composite layer was calculated by measuring the mass increasement(g) per unit surface($\textrm{cm}^2$). XRD and optical microscope were used to investigate the composition and phase of composites. The composite grown at 120$0^{\circ}C$ and with SiO2 dopant showed rapid growth rate. The growth behavior differed a little depending on the types of fiber used. The composites consist of $\alpha$-Al2O3, Al, Si and pore. The composite grown at 100$0^{\circ}C$ exhibited better microstructure compared to that grown at 120$0^{\circ}C$.

• Natural Product Sciences
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• 제18권4호
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• pp.244-249
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• 2012

Angelica acutiloba is one of the most intensively cultivated medicinal plants in Korea. The roots of this plant have been used as an important herbal drug, especially for the treatment of various female disorders, as the traditional therapy in Korea and other Asian countries. Consumption of its fresh leaves as a healthy vegetable has recently increased. In this study, essential oil fractions were extracted from the roots and leaves of this plant by steam distillation. Compositions of the two oils were compared by gas chromatography-mass spectrometry (GC-MS). The antibacterial activities of the essential oil were determined against three strains of Escherichia coli. DPPH radical scavenging and reducing power tests were performed to evaluateits antioxidant activities. The cytotoxic activities of the essential oil against a human breast and a uterine cancer cell line were estimated by MTT tests. Additionally, the morphological changes after treatment of the oil fraction were observed under a microscope. The essential oil fraction and its main components, Z-ligustilide and butylidene phthalide, inhibited the growth of three E. coli strains examined, with minimum inhibiting concentrations (MICs) ranging from 1.0 mg/ml to 8.0 mg/ml. Additionally, the essential oil fraction of A. acutiloba exhibited significant DPPH free radical scavenging activity and reducing power. Significant cytotoxic activities of the A. acutiloba essential oil were observed for human uterine (Hela) and breast (MCF-7) cancer cell lines.

• 상하수도학회지
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• 제28권5호
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• pp.589-600
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• 2014

Tuberculation and slime accumulated in water mains play an important role in modifying water quality of drinking water. Therefore, in this study, it was investigated that what materials were accumulated, and what components were included in the tuberculation and slime of water mains. The Various tuberculation and slime sample were collected from the 12 water mains to analyze their physical and chemical properties and crystal structure. As a analysis method, VSS(Volatile suspended solid), SEM(scanning electron microscope), EDS(Energy Dispersive X-ray spectroscope), ICP(Inductively Coupled Plasma Mass Spectrometer) and XRD(X-Ray Diffractomete) were used. The results of analysis on the samples, the representative materials were verified such as iron corrosion products, the fine sand particles generated during backwash, fine particles of activated carbon, aluminum used in coagulation process, and manganese included in raw water.

• Advances in materials Research
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• 제9권3호
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• pp.203-218
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• 2020

This research paper presents the outcomes in terms of mechanical and microstructural characteristics of binary and ternary concrete when exposed to elevated temperature. Three parameter were taken into account, (a) elevated temperature (i.e., 200, 400, 600 and 800℃) (b) binary concrete with cementitious material sugarcane bagasse ash (SCBA) and ground granulated blast furnace slag (GGBFS) replacement percentage (i.e., 0, 15, 20, 25 and 30%) and (c) ternary concrete with cementitious material SCBA and GGBFS replacement percentage (i.e., 0, 15, 20, 25 and 30%). A total of 285 standard cube specimens (150 mm × 150 mm × 150 mm) containing Ordinary Portland Cement (OPC), SCBA, and GGBFS were made. These specimens then exposed to several elevated temperatures for 2 h, afterword is allowed to cool at room temperature. The following basic physical, mechanical, and microstructural characteristics were then determined and discussed. (a) mass loss ratio, (b) ultrasonic pulse velocity (UPV) (c) physical behavior, (d) compressive strength, and (e) field emission scanning electron microscope (FESEM). It was found that compressive strength increases up to 400℃; beyond this temperature, it decreases. UPV value and massloss decrease with increase in temperature as well as the change in color and crack were observed at a higher temperature.