• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1069-1073
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• 2002

Properties of $B_4C/Al$ cermets were studied as a function of atmosphere during infiltration and post-heat treatment. The cermet A(infiltrated at $1100{\circ}C$/10 min under vacuum) had 19.4 wt% of Al but the cermet B(infiltratd at $1080{\circ}C$/10 min under a flowing argon) showed 14.4 wt% of Al. It indicated that the reaction between $B_4C$ and Al underwent slower under vacuum than under a flowing argon. The cermet B as infiltrated showed the density of 2.65 $g/cm^3$, the MOR of 503 MPa and the Young's Modulus of 237 GPa, but the post-heat treatment at $900{\circ}C$ for 8h under a flowing Ar gave rise to the cermet with the density of 2.65 $g/cm^3$, the MOR of 296 MPa, the Young's Modulus of 300 GPa. The cermet B showed better properties than the cermet A. Changes in compositions of the cermets by the post-heat treatment were observed qualitatively by XRD and SEM, the amount of Al was determined by analysis of its DSC curve.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.249-255
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• 2015

A soil microorganism producing iron chelator (siderophore) under low iron stress (up to $2{\mu}M$ of iron) was identified as Acinetobacter sp. B-W by 16S rDNA sequence analysis, biochemical-, physiological tests and morphological analysis using electron microscope. Catechol nature of siderophore was detected by Arnow test. Although optimal cell growth was identified at $36^{\circ}C$ in iron-limited media, significant quantities of siderophore were produced only at $28^{\circ}C$. Biosynthesis of siderophore was strongly inhibited by growth at $36^{\circ}C$. Production of siderophore was completely inhibited by $10{\mu}M\;FeCl_3$. Iron chelator produced from Acinetobacter sp. B-W was purified from supernatant using butanol extraction, Sephadex LH-20 column chromatography and HPLC. Purified sideropore was identified as 2,3-dihydroxybenzoic acid by HPLC, TLC and IR analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4191-4197
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• 2014

Value co-creation is an important business strategy these days in both the business-to-business (B2B) and business-to-consumer (B2C) markets. The aim of this study was to identify specialized resources and competences for value co-creation in the relationship network within a high-tech B2B market. A case of Taiwan Semiconductor Manufacturing Company Limited (TSMC) with customers and partners was chosen as the study case. Based on the observations, contents analysis of the secondary data and unstructured interviews with former TSMC employees, 4 critical resource types (financial, knowledge, efficiency and intellectual resource) and 6 competence types (relational, collaboration, strategic, innovation, managing and service capability), were performed as the principal factors for value co-creation in the relationship network. A research framework that can analyze the value co-creation phenomena in the relationship network was established.

• IT SoC Magazine
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• s.11
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• pp.11-25
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• 2006

• The Journal of Korean Society for Radiation Therapy
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• v.20 no.1
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• pp.17-23
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• 2008

Purpose: Cone-beam CT using linear accelerator attached to on-board imager is a image guided therapy equipment. Because it is to check the patient's set-up error, correction, organ and target movement. but imaging dose should be cause of the secondary cancer when taking a image. The aim of this study is investigation of appropriate cone beam CT scan mode to compare and estimate the image quality and skin dose. Materials and Methods: Measurement by Thermoluminescence dosimeter (TLD-100, Harshaw) with using the Rando phantom are placed on each eight sites in seperately H&N, thoracic, abdominal section. each 4 methods of scan modes of are measured the for skin dose in three time. Subsequently, obtained average value. Following image quality QA protocol of equipment manufacturers using the catphan 504 phantom, image quality of each scan mode is compared and analyzed. Results: The results of the measured skin dose are described in here. The skin dose of Head & Neck are measured mode A: 8.96 cGy, mode B: 4.59 cGy, mode C: 3.46 cGy mode D: 1.76 cGy and thoracic mode A: 9.42 cGy, mode B: 4.58 cGy, mode C: 3.65 cGy, mode D: 1.85 cGy, and abdominal mode A: 9.97 cGy, mode B: 5.12 cGy, mode C: 4.03 cGy, mode D: 2.21 cGy. Approximately, dose of mode B are reduced 50%, mode C are reduced 60%, mode D are reduced 80% a point of reference dose of mode A. the results of analyzed HU reproducibility, low contrast resolution, spatial resolution (high contrast resolution), HU uniformity in evaluation item of image quality are within the tolerance value by recommended equipment manufacturer in all scan mode. Conclusion: Maintaining the image quality as well as reducing the image dose are very important in cone beam CT. In the result of this study, we are considered when to take mode A when interested in soft tissue. And we are considered to take mode D when interested in bone scan and we are considered to take mode B, C when standard scan. Increasing secondary cancer risk due to cone beam CT scan should be reduced by low mAs technique.

• Food Science and Preservation
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• v.23 no.7
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• pp.1065-1073
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• 2016

This study investigated the sensory attributes and quality characteristics of Fuji apples based on market commodity price to provide data for quality index of Fuji apples. Samples were purchased from the Garak market (Seoul Agro-Fisheries & Food Corporation) and divided into four groups depending on the price such as group A, B, C, D. There were no significant differences in their volume and weight among groups. In the soluble solid content and total free sugar, A and B group (high price) showed higher content than those of C and D (low price) group. And also, the A group and B, C, D group showed 386.29 mg% and 320.09~359.28 mg% in the total organic acid content, respectively. As an sensory evaluation results, A group and B group were evaluated higher score than those of C and D group in the uniformity of red color and glossiness of skin and unique apple sensory attributes using quantitative descriptive analysis. Consumer test showed similar to quantitative descriptive analysis results in the various sensory attributes. In the analysis results between quality characteristics and sensory attributes of Fuji apples, total acceptability was correlated positively with titratable acidity (r=0.58), soluble solid (r=0.89), soluble solid content/titratable acidity ratio (r=0.42), total free sugar (r=0.36) and total organic acid (r=0.38). Based on principal component analysis of apple's quality characteristics, apples were primary separated along the first principal component (pH, acidity, soluble solid content, total free sugar, organic acid), which accounted for 66.01% of total variance. In addition, principal component analysis of sensory evaluation revealed a total variance for the quantitative descriptive of 55. 65% and a total variance for the consumer test of 55.84%.

• Composites Research
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• v.33 no.5
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• pp.241-246
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• 2020

In this study, aluminum (Al) alloy matrix composites in which B₄C particles were uniformly dispersed was manufactured through stir casting followed by hot rolling process. The microstructure, mechanical properties, and wear resistance properties of the prepared composites were analyzed. The composite in which the 40 ㎛ sized B₄C particles were uniformly dispersed increased the tensile strength and improved wear performance as the volume ratio of the reinforcement increased. In the case of the 20 vol.% composite, the tensile strength was 292 MPa, which was 155% higher than that of the Al6061. As a result of the wear resistance test, the wear width and depth of the 20 vol.% B₄C/Al6061 composites were 856 ㎛, and 36 ㎛, and the friction coefficient was 0.382, which were considerably superior to Al6061.

• Journal of radiological science and technology
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• v.22 no.2
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• pp.33-39
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• 1999

This paper included a data analysis of the unit of medical devices using mainternance recording card that had medical devices of unit failure mode, hospital of failure mode and MTBF. The results of the analysis were as follows : 1. Medical devices of unit failure mode was the highest in QC/PM such A hospital as 33.9%, B hospital 30.9%, C hospital 30.3%, second degree was the Electrical and Electronic failure such A hospital as 23.5%, B hospital 25.3%, C hospital 28%, third degree was mechanical failure such A hospital as 19.5%, B hospital 22.5%, C hospital 25.4%. 2. Hospital of failure mode was the highest in Mobile X-ray device(A hospital 62.5%, B hospital 69.5%, C hospital 37.4%), and was the lowest in Sono devices(A hospital 16.76%, B hospital 8.4%, C hospital 7%). 3. Mean time between failures(MTBT) was the highest in SONO devices and was the lowest in Mobile X-ray devices which have 200 - 400 failure hours. 4. Anverage failure ratio was the highest in Mobile X-ray devices(A hospital 31.3%, B hospital 34.8%, C hospital 18.7%), and was the lowest in Sono(Ultrasound) devices (A hospital 8.4%, B hospital 4.2%, C hospital 3.5%). 5. Failure ratio results of medical devices according to QC/PM part of unit failure mode were as follows ; A hospital was the highest part of QC/PM (50%) in Mamo X-ray device and was the lowest part of QC/PM(26.4%) in Castro X-ray. B hospital was the highest part of QC/PM(56%) in Mobile X-ray device, and the lowest part of QC/PM(12%) in Gastro X-ray. C hospital was the highest part of QC/PM(60%) in R/F X-ray device, and the lowest a part of QC/PM(21%) in Universal X-ray. It was found that the units responsible for most failure decreased by systematic management. We made the preventive maintenance schedule focusing on adjustement of operating and dust removal.

• Animal Systematics, Evolution and Diversity
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• v.12 no.4
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• pp.331-347
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• 1996

The geographic distribution and variation for Rhinogobius brunneus were surveyed by means of allozymic and morphological analyses and it was revealed that the Korean populations of R. brunneus comprise three distinct types, Type-A, Type-B, and Type-C, which show considerable differentiation to a degree of interspecific level(Rogers' S(1972): $S_{A-B}$=0.631, $S_{A-C}$=0.628, $S_{B-C}$=0.661). In addition, no evidence of gene flow among the types was found at sympatric area and it is assumed that reproductive isolation is completed. Moreover there is microhabitat segregation according to the distance from river mouth among each types and which segregation was regarded as a factor to facilitate reproductive isolating mechanism. Therefore, based on the evidence presented above, these three types of R. brunneus are considered as typical discrete species.

• Food Engineering Progress
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• v.14 no.1
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• pp.75-79
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• 2010

Partial least square regression (PLSR) was executed on curve data of force-deformation from back extrusion test and sensory data for commercial instant noodles. Sensory attributes considered were hardness (A), springiness (B), roughness (C), adhesiveness to teeth (D), and thickness (E). Eight and two kinds of fried and non-fried instant noodles respectively were used in the tests. Changes in weighted regression coefficients were characterized as three stages: compaction, yielding, and extrusion. Correlation coefficients appeared in the order of E>D>A>B>C, root mean square error of prediction D>C>E>B>A, and relative ability of prediction D>C>E>B>A. Overall, 'D' was the best in the correlation and prediction. 'A' with poor prediction ability but high correlation was considered good when determining the order of magnitude.