• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.1-14
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• 2011

Water is the most precious resource to human being, but it is polluted by different organic compounds. Organic matter (OM) in aqeous solutions is one of the important parameters of concern for human and environmental impact, and thus, it is essential to better characterize specifically targeted organic matter in aggregated and individual level of concentrations. This review presents different analytical tools and protocols to investigate detailed properties and characterization. Physical, chemical and biological aspects of OM are envisaged in terms of traditional and advanced measurement methods.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.10a
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• pp.113-117
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• 2003

The reliability of machined fiber reinforced composites (FRC) in high strength applications and the safety in using these components are often critically dependent upon the quality of surface produced by machining since the surface layer may drastically affect the strength and chemical resistance of the material [1,2,3,4]. Current study will discuss the characterization of fiber pull-out in orthogonal cutting of a fiber-matrix composite materials. A sparsely distributed idealized model composite material, namely a glass reinforced polyester (GFRP) was used as workpiece. Analysis method employs a force sensor and the signals from the sensor are processed using AR time series model. The experimental correlation between the fiber pull-out and the AR coefficients is examined first and effects of fiber orientation, cutting parameters and tool geometry on the fiber pull-out are also discussed.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.1
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• pp.155-163
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• 2000

A general characterization procedure based on the extraction of a 2n-port admittance matrix corresponding to n uniform coupled lines on the multi-layered substrate using the Finite-Difference Time-Domain (FDTD) technique is presented. The frequency-dependent normal mode parameters are obtained from the 2n-port admittance matrix, which in turn provides the frequency-dependent distributed inductance and capacitance matrices. To illustrate the technique, several practical coupled line structures on multi-layered substrate, including a three-line structure, have been simulated. It is shown that the FDTD based time domain characterization procedure is an excellent broadband simulation tool for the design of multiconductor coupled lines on multilayered PCBs as well as thick or thin hybrid structures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.373-379
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• 2009

Presented in this paper is a new experimental technique to measure material properties of lock plate of gas turbine plants by using ultrasonic guided wave. In comparison with the mechanical destructive testings, material characterization of the Inconel x-750 was nondestructively carried out in a more efficient manner to discriminate the change in elastic moduli and the poisson's ratio attributed to the variation of heat treatment condition. The proposed technique shows a satisfactory feasibility via the comparative experiments with the imported lock plate specimens. It is also expected that the guided wave technique can cover a longer and wider range as a new cost-&-time-saving inspection tool due to the interaction with a greater part of specimen, compared to a conventional local point-by-point scheme.

• Applied Microscopy
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• v.46 no.3
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• pp.117-126
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• 2016

Atom probe tomography (APT) has been fast rising in prominence over the past decade as a key tool for nanoscale analytical characterization of a range of materials systems. APT provides three-dimensional mapping of the atom distribution in a small volume of solid material. The technique has evolved, with the incorporation of laser pulsing capabilities, and, combined with progress in specimen preparation, APT is now able to analyse a very range of materials, beyond metals and alloys that used to be its core applications. The present article aims to provide an overview of the technique, providing a brief historical perspective, discussing recent progress leading to the state-of-the-art, some perspectives on its evolution, with targeted examples of applications.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.429-432
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• 2005

Geophysical investigations, as a non-invasive method, were conducted at the former gas station site contaminated with fuel hydrocarbons. GPR (Ground Penetrating Radar) survey was performed to locate buried objects such as USTs (Underground Storage Tanks) and fuel pipes which might serve as a origin of the site contamination. Additional GPR investigation and a resistivity survey were conducted to map water table and to characterize shallow geologic structures of the site. The results of the study have shown that seven USTs including one unknown UST and buried fuel pipes are present, and that the groundwater elevation varies with topography from approximately 1.5 to 3m below the surface and the water table is located in the residual soils above the bedrock in the site. The results also show that the geophysical methods can be a very useful tool for the characterization of the contaminated site.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3118-3126
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• 1994

This paper describes the use of the concept of (relative) entropy for effective characterization of the amplitude and the frequency distributions of the surface profile formed in machining operation. For this purpose, a theoretical model for surface texture formation in turning operation is developed first. Then, the concept of (relative) entropy is reviewed and its effectiveness is examined based on the simulation and experimental results. The results also suggest that under random tool vibration the effect of the geometrical factors on the surface texture formation can be successfully decomposed and therefore, identified by applying the concept of (relative) entropy.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.255-262
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• 2016

The carrageenan-degrading marine bacterium Vibrio sp. strain NJ-2 was isolated from rotten red algae, and κ-carrageenase with high activity was purified from the culture supernatant. The purified enzyme with molecular mass of 33 kDa showed the maximal activity of 937 U/mg at 40℃ and pH 8.0. It maintained 80% of total activity below 40℃ and between pH 6.0 and 10.0. The kinetics experiment showed the K_m and V_max values were 2.54 g/ml and 138.89 mmol/min/mg, respectively. The thin layer chromatography and ESI-MS analysis of hydrolysates indicated that the enzyme can endolytically depolymerize the κ-carrageenan into oligosaccharides with degrees of depolymerization of 2-8. Owing to its high activity, it could be a valuable tool to produce κ-carrageenan oligosaccharides with various biological activities.

• Journal of the Optical Society of Korea
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• v.8 no.1
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• pp.34-52
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• 2004

Over the past decade the experimental technique of THz time domain spectroscopy (㎔- TDS) has proved to be a versatile method for investigating a wide range of phenomena in the ㎔ or far infrared spectral region from 100 ㎓ to 5 ㎔. This paper reviews some recent results of the Ultrafast ㎔ Research Group at Oklahoma State University using ㎔-TDS as a characterization tool. The experimental technique is described along with recent results on ㎔ beam propagation and how ㎔ beam profiles arise from propagation of pulse fronts along caustics. To illustrate how spatio-temporal electric field measurements can determine material properties over a wide spectral range, propagation of ㎔ pulses through systems exhibiting frustrated total internal reflection (FTIR) are reviewed. Finally two potential metrology applications of ㎔-TDS are discussed, thin film characterization and non-destructive evaluation of ceramics. Although ㎔-TDS has been confined to the research laboratory, the focus on application may stimulate the adoption of ㎔- TDS for industrial or metrology applications.

• Bulletin of the Korean Chemical Society
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• v.19 no.1
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• pp.5-21
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• 1998

The purpose of this paper is to show that X-ray absorption spectroscopy (XANES and EXAFS) is a powerful technique for characterizing both crystalline and amorphous solids from structural (local order) and electronic point of view. The principle of this technique is briefly described by showing the main factors which must be considered for recording and fitting the experimental results. Some non-trivial examples have been selected for demonstrating that XAS spectroscopy is the only technique for bringing a definitive answer as for example: the determination of the local distortion of the $NiO_6$ octahedra in the $Li_{1-z}Ni_{1+z}O_2$ layered oxides and the evidence of the presence of copper pairs in the NASICON-type phosphate $CuZr_2 (PO_4)_3$. Are also reported some significant examples for which XAS spectroscopy is decisive with other characterization methods as (i) Raman spectroscopy for glasses (ii) Mossbauer spectroscopy for $LiNi_{1+z-t}Fe_To_2$ oxides (iii) magnetic measurements for Ce-based intermetallic compounds.