• Journal of radiological science and technology
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• v.31 no.1
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• pp.49-54
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• 2008

After x-ray 5Gy radiation on the whole body of a mouse using a linear accelerator, its leucocyte, erythrocyte, and platelet were observed by SEM. Also, after injecting propolis into the abdominal cavity, the radio-protective effect of blood corpuscles was studied. The observation of micromorphology in blood corpuscles revealed that the number of leukocyte, erythrocyte, and thrombocyte decreased in the experimental group and the lump got together in blood corpuscles after 10 and 20 days. In RBC, crack or break on the surface and poikilosperocytes were observed. In the irradiation group, the size of leucocytes was smaller than that in control group and the number of villus at the verge substantially decreased. The blood corpuscles in the propolis group, however, had the similar results to control group.

• Journal of Distribution Science
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• v.14 no.8
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• pp.45-50
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• 2016

Purpose - This study aimed to develop a new practical and universally applicable service quality model by improving the service quality measurement model proposed by many previous studies. Research design, data, and methodology - An in-depth analysis on what influences such service quality model had on the improvement effect of service quality, and Service Evaluation Model("SEM"), which was revised from the existing service quality measurement model, was developed. The model is divided into the two integrative categories: First, activity, that is the group of service-related activities. Next is item, the group of service-related objects. The level of service is evaluated for each category via survey questionnaire on service level evaluation. Based on the model, SEM has visibility by structuring the whole service industry. Results - For the application of the new service quality model, this study attempted to examine the appropriateness of the newly proposed service quality model by applying it to retail service field. Conclusions - As a result, the proposed service model would be a useful and applicable service quality measurement model required by many organizations. Service company can set up self check service levels. Through these results, they can look for the ways to provide better services to customers. Service users can ensure the objectivity of business plan based upon SEM.

• Korean Journal of Materials Research
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• v.16 no.5
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• pp.312-317
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• 2006

Binary skutterudite $CoSb_3$ compounds were prepared by the encapsulated induction melting (EIM) process, and their thermoelectric, microstructural and mechanical properties were examined. Single-phase ${\delta}-CoSb_3$ was successfully produced by the EIM and subsequent heat treatment at 773 K-873 K for 24 hours in vacuum. Seebeck coefficient increased with increasing heat treatment temperature up to 673 K, showing the positive signs in the range of measuring temperature. However, the samples heat-treated at 773 K-873 K showed negative Seebeck coefficient from room temperature to 400 K, while it showed positive signs above 400 K. Electrical resistivity decreased with increasing temperature, showing typical semiconducting conductivity. Thermal conductivity decreased drastically with increasing heat-treatment temperature. This is closely related with the phase transition to ${\delta}-CoSb_3$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.324-324
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• 2010

최근에는 압전체의 환경오염 문제의 해결 및 가격경쟁력을 갖추기 위해서 비납계 압전체에 대한 연구가 활발히 진행되고 있다. (Na,K)$NbO_3$ 계는 페로브스카이트 구조를 가지는 비납계 세라믹스로 현재 가장 많이 연구되고 있는 물질 중의 하나이다. 본 연구에서는 압전성이 우수한 $(Na_{0.44}K_{0.52}Li_{0.04})(Nb_{0.9}Ta_{0.04}Sb_{0.06})O_3$ 조성에 CuO, $Cu_2O$ 등의 Cu 산화물을 첨가하였을 때의 전기기계결합계수, 기계적품질계수, 비유전율, 압전전하상수, 문극-전계 이력곡선 (P-E hysteresis curve) 등을 변화를 평가하고자 하였다.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.4
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• pp.400-406
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• 2015

This study researched the structure of the source of an ion milling machine used to fabricate a scanning electron microscope (SEM) sample. An ion source is used to mill out samples of over 1 mm dimension using a broad ion beam to generate plasma between the anode and cathode using a permanent magnet. To mill the sample in the vacuum chamber, the ion source should be greater than 6 kV for a positive ion current over $200{\mu}A$. To discover the optimum operating conditions for the ion miller, the diameter of the extractor, anode shape, and strength of the permanent magnet were varied in the experiments. A silicon wafer was used as the sample. The sputter yield was measured on the milled surface, which was analyzed using the SEM. The wafer was milled by injecting 1 sccm of argon gas into the 0.5 mTorr vacuum chamber.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.9
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• pp.55-62
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• 2003

This paper investigates the micro-cutting of cemented carbides using PCD (polycrystalline diamond) and PCBN (polycrystalline cubic boron nitride) cutting tools are performed with SEM direct observation method. The purpose of this study is to make clear the cutting mechanism of cemented carbides and the fracture of WC particles at the plastic deformation zone in orthogonal micro-cutting. And also to achieve systematic understanding, the effect of machining parameter on chip formation and machined surface was studied, including cutting speed, depth of cut and various tool rake angle. Summary of the results are shown below. (1) Three type of chip formation process have been proposed by the results of the direct observation in orthogonal micro-cutting of cemented carbide materials. (2) From the whole observation of chip formation, primary WC particles are crushed and/or fine grained in the shearing deformation zone. A part of them are observed to collide directly with a cutting edge of tool by following the micro-cutting. (3) Surface finish, surface morphology and surface integrity is good to obtain by cutting with PCD cutting tool compared with PCBN. (4) The machined surface has the best quality near the low cutting speed of 10${\mu}m$/sec with a cutting depth of 10 ${\mu}m$ using 0$^\circ$ rake angle and 3$^\circ$ flank angle in this condition, but it was found that excessively low speed, for example the extent of 1 ${\mu}m$/sec, is not good enough to select for various reason.

• Journal of Environmental Science International
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• v.26 no.12
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• pp.1333-1339
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• 2017

Coal-fired power plants emit various Particulate Matter(PM) at coal storage pile and ash landfill as well as the stack, and affect the surrounding environment. Field Emission Scanning Electron Microscopy and Energy Dispersive X-ray analyzer(FE-SEM/EDX) were used to develop identification factor and the physico-chemical analysis of PM emitted from a power plant. In this study, three samples of pulverized coal, bottom ash, and fly ash were analyzed. The pulverized coal was spherical particles in shape and the chemical composition of C-O-Si-Al and C/Si and C/Al ratios were 200~300 on average. The bottom ash was spherical or non-spherical particles in shape, chemical composition was O-C-Si-Al-Fe-Ca and C/Si and C/Al ratios were $4.3{\pm}4.6$ and $8.8{\pm}10.0$. The fly ash was spherical particles in shape, chemical composition was O-Si-Ai-C-Fe-Ca and C/Si and C/Al ratios were $0.5{\pm}0.2$ and $0.8{\pm}0.5$.

• Journal of the Korean Geosynthetics Society
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• v.10 no.4
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• pp.19-28
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• 2011

This paper presents the results of an investigation into the effect of cyclic wetting-drying on the compressive strength characteristics of decomposed granite soils. A series of plane strain compression (PSC) tests were performed on test specimens with varying fine contents under different wetting-drying cycles to investigate the change in compressive strength under the process of wetting-drying cycles. The effect of wetting-drying cycles on the structural particle rearrangement at a micro-scale level was also examined using scanning electron microscope (SEM) tests. It was shown that the soil containing larger fines showed more significant decrease in compressive strength compared with the soils with less fines. Also found was that the wetting-drying cycle did not have significant effect on the particle arrangement.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.3
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• pp.270-277
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• 2015

In this paper, we describe the production of a specific electrostatic-type scanning electron microscope based on miniaturization for application in other types of vacuum equipment. The initial configuration of the SEM starts with a minimal configuration that allows people to view sample images. After improving the stability of the SEM operation and resolution, we conducted experiments on identifying the characteristics and development of an einzel-type condenser lens with reference to the demagnification lens system of an SEM. The experiments were conducted at an acceleration voltage of 5 kV and we found the shape of the lens to be more reliable than a conventional lens. The lens was then added to improve the resolution in the nanometer region. The current measured on the sample was approximately 40 pA and its magnification was 4,000 times.

• Journal of Korean society of Dental Hygiene
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• v.8 no.4
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• pp.241-250
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• 2008

In this study, specimens such as tongue, supragingival and subgingival biofilm were taken from total 20 scaling subjects who visited the oral prophylaxis practice lab at department of dental hygienics, J Health College in order to observe bacterial distributions and morphology using scanning electron microscopy(sem). as a result, this study came to the following conclusions: 1. According to observation of tongue, supragingival and subgingival biofilm through sem, it is found that there are round colonies of gram-positive cocci and gram-negative bacilli on blood agar medium. 2. The observation of bacterial morphology on dental biofilm through sem, cocci in chain cocci in cluster and bacillus(rod) respectively. 3. For tongue biofilm, it is found that a variety of bacterial species are detected, such as Granulicatolla adiacens(1), Gemella morbillorum(3), Streptococcus mitis(2), Streptococcus sanguinis(1), Aerococcus viridans (2), Streptococcus equinus(1), Leuconostoc spp.(1), Gemella haemolysans (1) and Lactococcus lactis spp.(1) respectively. 4. For supragingival biofilm, it is found that a variety of bacterial species detected, such as Aerococcus viridans(1), Gemella haemolysans(2), Leuconostoc spp.(2), Gemella morbillorum(1) and Pseudomonas fluoescens (1) respectively. 5. For subgingival biofilm, it is found that a variety of bacterial species detected, such as Leuconostoc spp.(1), Staphylococcus lugdunensis(1) and Streptococcus salivarius(1) respectively.