• Journal of the Korean Society of Safety
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• v.34 no.2
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• pp.7-14
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• 2019

A palladium can adsorb hydrogen and detect leaking hydrogen through changes in color and electrical resistance. This study is to evaluate the structural behavior of carbon fiber adding palladium composite materials used in the hydrogen storage vessel. A multi-scale analysis technique was used to analyze accurately the behavior of each material in relation to the microscopic composition. The multi-scale analysis is more proper and precise for composite materials because of considering the individual microscopic structure and properties of each material for composite materials. Also the crack evaluation was performed by XFEM analysis to confirm the reinforcement performance of aluminum as a liner of the hydrogen vessel. The results show that the addition of the palladium material increased the macroscopic stress, but microscopically the carbon fiber stress was reduced. It means the performance improvement of the palladium added carbon fiber/Al composite.

• Microbiology and Biotechnology Letters
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• v.5 no.3
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• pp.133-140
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• 1977

The results of electron microscopic studies on the cell fine structure of Nocardia sp the location of tellurite-reducing enzyme and the reduction part of T. T. C. (Triphenyl tetrazonium chloride) were summarized as follows. As the fine structure of the cell, the membrane-like structure with unit membrane was distributed in the cytoplasm. The membrane-like structure had complicate forms: some of membrane-like structure appeared spiral form. As the metal tellurium salt appeared in the cytoplasm, it is obvious that tellurite and tellurate-reducing enzymes are present in the cytoplasm. Reduction of T. T. C. took place in the cell membrane and the intracellular membrane-like structure. Therefore, it was thought that reduction of tellurate and T. T. C. took place in different parts. T. T. C. formazane formed in the cell was reoxidized by osmic acid which was used as a fixation reagent for the electron microscopic specimen preparation. As 95％ T. T. C. formazane was soluble in ethanol and embedding materials and removed out of the cell, an originally formed formazane appeared as electron light part on the electron microscopic image.

• Applied Microscopy
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• v.36 no.3
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• pp.209-216
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• 2006

Accuracy and precision of the goniometer and the specimen holder should be measured and corrected to improve reliability of 3-D structure analysis using transmission electron microscopy (TEM). In this study, we described the operation principle and performance of the Gatan rotation holder. Through analysis of the images taken inside the microscope, rotation angles were measured within the accuracy of ${\pm}0.42^{\circ}$. For comparison the rotation angles were measured outside the microscope using a home-made measurement tool, which resulted in the accuracy of ${\pm}0.6^{\circ}$. Additionally, we found abnormal specimen drifts during rotation probably due to the unstable engagement between the specimen cup and the rotation belt.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.613-622
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• 2003

The multi-configurative microscopic system for inspecting the wire-bonding of reed frame is designed. Rays refracted by objective lens group which is composed of common lens group of x2 and x6 are splitted by beam-splitter, and Rays through the central region and the boundary region of the object imaged at x2 and x6 through imaging lens groups, respectively. The depth of wire structure on the reed frame has about $\pm$3 mm, in order to observe by uniform magnification without the dependency on the variation of objective distance generated by the depth of wire structure on the reed frame, imaging lens groups should be moved on nonlinear locus like mechanically compensated zoom lenses. The nonlinear equations for zoom locus are derived by using the Gaussian bracket. Refraction powers and positions of each groups are numerically determined by solving the equations, and initial design data for each groups is obtained by using Seidel third order aberration theory. The optimization technique is finally utilized to obtain this microscopic system.

• Applied Microscopy
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• v.39 no.4
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• pp.341-348
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• 2009

The crystal structure of nano-crystalline, $BaTiO_3$, with the average particle size of 100 nm was investigated using electron diffraction techniques. We characterized the precession electron diffraction system and then carried out the structure determination using precession electron diffraction and conventional selected area electron diffraction. As a result, it was revealed that $BaTiO_3$ nano-crystalline exist as a mixture of tetragonal structure and cubic structure by precession electron diffraction technique. In addition, it could be turned out that $BaTiO_3$ nano-crystalline is a core-shell structure consisted of a tetragonal phased core and a cubic phased surface layer by theoretical calculation. The thickness of the cubic surface layer was approximately 8.5 nm and the lattice parameters of cubic and tetragonal phases were a=3.999${\AA}$ and a=3.999${\AA}$, c=4.022${\AA}$, respectively. Finally, it is expected that precession electron diffraction is more useful technique for structure determination of complicated nano-crystalline materials because of its higher spatial resolution and minimization of dynamical scattering effect.

• Korean journal of food and cookery science
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• v.1 no.1
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• pp.57-64
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• 1985

This study was conducted to investigate the effect of fat on structure and texture of soybean curds by partial or whole replacement of soybean with defatted soy flour, The textural properties of soybean curd were examined by Instron universal testing machine, and the microscopic structure of soybean curds was examined by Scanning electron microscope(SEM). The results obtained were as follows ; 1. Textural parameters determined by Instron universal testing machine showed that hardness and gumminess of soybean curs were significantly increased as the fat contents of the samples decreased. On the while, springiness of the samples were significantly lowered as the fat content decreased. 2. Microscopic structure of soybean curds examined by SME demonstrated that samples with high fat had more fat globules and thinner network layer which were assumed to surround moisture with.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.6
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• pp.42-47
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• 2001

In this study, fatigue limit of ductile cast iron is evaluated based on phenomena of the microscopic observation, such as matrix structure, spheroidal ratio, size of graphite and distribution. Three different ferrite-pearlite matrix structure, GCD 45-), GCD 50, GCD 60 series, all of which contain more than 70% spheroidal ratio of graphite, were used to obtain the correlation between maximum size of graphite and fatigue strength. It was concluded as fellows. (1) In Ductile cast iron of ferrite-pearlite matrix, the fatigue limit of GCD 60 series with 73% pearlite structure was the highest. (2) From observation of the starting point of crack of all specimens, it is noted that the crack initiates, in graphite, goes through ferrite and propagates into pearlite. (3) A good quality of Ductile cast iron used in this experiment can be checked from uniformly distributed graphite. The negligible interaction effect between graphites was verified by microscopic observation and fracture mechanics investigation in surface and interior of the specimen.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.497-500
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• 2004

Recently, the use of structure compound waterproof agent (hereinafter referred to as 'SCWA') that is used when manufacturing concrete for concrete structures, increases in quantity. However, while it is expected that the SCWA that is mixed in the concrete inside can significantly affect the change of physical properties that lift the internal force of a structure. This study has been conducted through an experiment for the effects of cement hardener on the formation of microscopic texture, and newly generated hydrates from that result were not confirmed in the present experiment. It was found that at the hydrate reaction it has the property that can be hardened within the limit of pore diameterar a specific size rather than there is the internal gap filling capacity due to generating other hydrates.

• Applied Microscopy
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• v.52
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• pp.6.1-6.5
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• 2022

We examined the morphology of the fertilized egg and the fine structure of fertilized egg envelopes of Poropanchax normani belonging to the family Poeciliidae, also known as Norman's lampeye using light and electron microscopes. The fertilized eggs with narrow perivitelline space were found to be spherical and demersal, additionally containing small oil droplets in the vitelline membrane. Further, a bundle of adhesive filaments was observed to be present on one side of the fertilized egg. These filaments possessed remarkably high elasticity and were approximately 1-3mm in length. The size of the fertilized egg was determined to be about 1.49 ± 0.07mm (n=30). The outer surface appeared smooth, and adhesive filaments originating at different location of the surface of the envelope were found to be distributed around the egg envelope and were joined together to form a single long bundle in scanning electron microscopic observation. A peak-like structure formed of several straight wrinkles was observed around the micropyle. However, the complete structure of the micropyle could not be studied due to the depth at which it was located. Additionally, the total thickness of the egg envelope was ascertained to be approximately12.5-14.5㎛. The egg envelope consisted of two distinct layers, an outer electron dense layer and an inner lamellar layer, further consisting of 10 sublayers of varying thicknesses. Collectively, it was observed that the morphological characteristics of the fertilized egg, fine structures surrounding the micropyle, outer surface, adhesive structure consisting adhesive filaments, and sections of fertilized egg envelope displayed species specificity.

• Applied Microscopy
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• v.44 no.4
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• pp.138-143
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• 2014

Transmission electron microscope (TEM) is an excellent tool for studying the structure and properties of nanostructured materials. As the development of $C_s$-corrected TEM, the direct analysis of atomic structures of nanostructured materials can be performed in the high-resolution transmission electron microscopy (HRTEM). Especially, fast Fourier transform (FFT) technique in image processing is very useful way to determine the crystal structure of HRTEM images in reciprocal space. To apply FFT technique in HRTEM analysis in more reasonable and friendly manner, we made a new circular region of interest (C-ROI) FFT script and tested it for several HRTEM analysis. Consequentially, it was proved that the new FFT application shows more quantitative and clearer results than conventional FFT script by removing the streaky artifacts in FFT pattern images. Finally, it is expected that the new FFT script gives great advantages for quantitative interpretation of HRTEM images of many nanostructured materials.