• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.409-410
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• 2006

In this study, the tempering effect on the wear characteristics of induction-hardened SPS5 steel was investigated. For this purpose, three tempering conditions were applied to control the hardness of heat-treated SPS5 steel. Ball-on-disk wear tests have been performed using zircornia balls on the tempered specimens to determine the variation of wear characteristics. The results showed that friction coefficient decreased with increasing hardness for induction hardening conditions. This seems to occur because real contact area between specimen and mating ball was affected by the specimen hardness.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.10-12
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• 2014

In ISO 10140-5:2010, defines the reverberation time conditions of the receiving room. The sound absorption side of test specimen is installed in the source room generally. In this study, examined at the change in the sound insulation characteristics for the test specimen of asymmetric structure attached sound absorbing material by changing the installed position. A difference of sound insulation performance was maxium Rw 1 dB, it is preferable to place the larger sound absorption area in source room.

• Applied Microscopy
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• 제46권2호
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• pp.110-115
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• 2016

Transmission electron microscopy (TEM) is a powerful tool for analyzing a broad range of materials and provides localized information about the microstructure. However, the analysis results are strongly influenced by the quality of the thin foil specimen. Sample preparation for TEM analysis requires considerable skill, especially when the area of interest is small or the material of interest is difficult to thin because of its high hardness and its mechanical instability when thinned. This article selectively reviews recent advances in TEM sample preparation techniques using a tripod polisher. In particular, it introduces two typical types (fl at type and wedge type) of TEM sample preparation and the benefits and drawbacks of each method; finally, a method of making better samples for TEM analysis is suggested.

• Fisheries and Aquatic Sciences
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• 제16권3호
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• pp.195-197
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• 2013

One specimen of Chirolophis saitone, belonging to the family Stichaeidae, was collected by a bottom trawl in the southern area of the Yellow Sea. The present specimen was characterized by 52 dorsal fin spines, 38 anal fin spines, a caudal fin with four vertical dark bands and an orbital region with three pairs of branched cirri. We propose a new Korean name, "Jak-eun-goe-do-ra-chi', for C. saitone.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.258-263
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• 2005

Because of its high performance and accuracy, electron beam welding has an important role in industrial applications such as semi-conductor and LCD manufactures. Since its operation has been done in a vacuum room, it is very difficult to check out their weldability as well as the correct welding area of the specimen. In this study, a measurement system of the electron beam welding has been developed based on the 3-axis LVDT controlled table. In addition, the algorithm to tracking the welding line has been developed. Welded regions were measured by using an A-scan ultrasonic sensor only. Weldability of the aluminum specimen has been tested by newly developed measuring system. The results are compared with those by using an C-scan ultrasonic sensor, which show good agreements with each other.

• 환경생물
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• 제37권1호
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• pp.68-71
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• 2019

An asteroid specimen that belongs to the genus Henricia was collected from the waters near Ongpo harbor, Jeju Island using fishing net on 24 January 2017. The specimen was identified as Henricia anomala Hayashi, 1973, which belongs to the family Echinasteridae and order Spinulosida. Henricia anomala was first described by Hayashi, 1973, who captured it from Sagami Bay at a depth of 110-116 m. This species can be distinguished from other Henricia species by short arms (R/r=4), abactinal spines lining the abactinal plates and bearing about two to five spinelets, closely meshed abactinal skeleton, composed of small rod-like and subtriangular plates, a narrow papular area containing one or two papulae, and adambulacral armature composed of five to seven bluntly pointed spinelets. This is the first report of Henricia anomala in Korea.

• Animal Systematics, Evolution and Diversity
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• 제36권4호
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• pp.420-423
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• 2020

As a result of continuous taxonomic studies on the Korean crabs, Carcinus aestuarii Nardo, 1847 belonging to the superfamily Portunoidea is newly reported from Korean waters. Carcinus aestuarii has characteristics as followings: cardiac, hepartic and brachial regions are divided by deep furrow; shape of three lobes in frontal area is flatter with hairy; inside of carpus is with one sharp tooth; the posterior-lateral margin of the carapace is concave, and so on. The examined specimen doesn't have hairy and bump on outer margin of the chelipeds which differed from the previous description of the specimens collected from Tokyo Bay, Japan. Here, the diagnosis and the picture of Korean specimen is provided. Korean portunoids currently consist of 20 species belonging to 10 genera.

• Journal of Species Research
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• 제12권1호
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• pp.27-37
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• 2023

Kushia zosteraphila Harris V.A. & Iwasaki, 1996 is newly collected and described from macroalgae in the intertidal region of Gijang-gun, along the southeastern coastal region of Korea. Kushia zosteraphila can be distinguished from congeners by following morphological characteristics: the length of the first dorsal seta similar with the second dorsal seta of female P5, the length to width ratio of the female caudal ramus, and the presence of a conspicuous comb on the accessory lobe of the male antennule. Although there are some minor discrepancies, the main diagnostic characteristics of the specimen from the study area are well-matched with the original description. We herein provide detailed morphological descriptions and illustrations of this species. According to a survey of the location of the reported porcellidiid species in Korea, this specimen is the second record in Korean waters of the genus Kushia. A key to species of the family Porcellidiidae in Korea is provided. A partial sequence of the mitochondrial COI gene was obtained and provided as a DNA barcode for this species.

• 환경영향평가
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• 제17권4호
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• pp.225-233
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• 2008

An Environmental Specimen Bank (ESB) is an archive for samples that can be used to document and assess the quality of the environment in which we live. An ESB program looks at changes in the concentration of human and environmental specimens over long periods of time through retrospective analysis of archived samples of a particular area collected at regular intervals. The idea of ESB was first proposed by German and American scientists in the early 1970s and has been established since 1979 in Germany, USA, and Japan. Korea plans to establish a National Environmental Specimen Bank (NESB) in 2010. The NESB will be able to assess and improve the quality of analytical measurements as well as to compare the past and current environmental quality as a time capsule. The concept and design for the NESB facility was developed and its Standard Operation Procedures (SOPs) are being developed based on an evaluation of ESBs and SOPs of Germany, USA, and Japan. Environmental specimens proposed for banking are based on typical representatives of every level of the food chain from each type of ecosystem that are widely distributed thus enabling comparisons between different sampling areas. Through retrospective analysis of environmental specimens, the NESB will improve the reliability of environmental monitoring, ecological risk assessment, and health impact assessment.

• Smart Structures and Systems
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• 제26권5호
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• pp.657-666
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• 2020

A rotational pulse-echo ultrasonic propagation imager that can inspect cylindrical specimens for material nondestructive evaluations is proposed herein. In this system, a laser-generated ultrasonic bulk wave is used for inspection, which enables a clear visualization of subsurface defects with a precise reproduction of the damage shape and size. The ultrasonic waves are generated by a Q-switched laser that impinges on the outer surface of the specimen walls. The generated waves travel through the walls and their echo is detected by a Laser Doppler Vibrometer (LDV) at the same point. To obtain the optimal Signal-to-Noise Ratio (SNR) of the measured signal, the LDV requires the sensed surface to be at a right angle to the laser beam and at a predefined constant standoff distance from the laser head. For flat specimens, these constraints can be easily satisfied by performing a raster scan using a dual-axis linear stage. However, this arrangement cannot be used for cylindrical specimens owing to their curved nature. To inspect the cylindrical specimens, a circular scan technology is newly proposed for pulse-echo laser ultrasound. A rotational stage is coupled with a single-axis linear stage to inspect the desired area of the specimen. This system arrangement ensures that the standoff distance and beam incidence angle are maintained while the cylindrical specimen is being inspected. This enables the inspection of a curved specimen while maintaining the optimal SNR. The measurement result is displayed in parallel with the on-going inspection. The inspection data used in scanning are mapped from rotational coordinates to linear coordinates for visualization and post-processing of results. A graphical user interface software is implemented in C++ using a QT framework and controls all the individual blocks of the system and implements the necessary image processing, scan calculations, data acquisition, signal processing and result visualization.