• 한국분말재료학회지
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• 제13권5호
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• pp.360-365
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• 2006

The phase stability of tetragonal phase in Y-TZP was investigated in terms of the distribution of grain sizes and heat-treating atmosphere. Y-TZP with various grain sizes were prepared using duration time at $1600^{\circ}C$ as experimental parameter. Accumulated grain size distributions were built from the SEM micrographs and the amount of tetragonal phase were measured using XRD. Both results were compared to determine the critical grain size before and after heat-treatment in vacuum. The critical grain size drastically decreased compared with the small increase of average grain size due to the autocatalytic effect which critically affects the tetragonal to monoclinic phase transformation. After heat-treatment in reductive atmosphere critical grain size relatively increased due to the stabilization of tetragonal phase. The formation of oxygen vacancies during heat-treatment was ascribed to the increase of stability.

• 한국생활과학회지
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• 제11권4호
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• pp.401-413
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• 2002

The purpose of this study was to survey the high school girls' alteration of school uniforms concerned about both size satisfaction and dissatisfaction and to improve the size of school uniforms. The subjects were 1,007 girls attending high schools in Cheju. The questionnaire survey was done from July 8th to Sep. 21th, 2001. According to the survey, 67.3 percentile of the interviewed girls alterated their uniforms. It was appeared that they alterated skirts more than blouses as a way of shortening. The main reason of alteration is ill-fitting uniforms, most of girls had a positive idea to alterate uniforms. Dissatisfaction of uniforms is mainly caused by the large size not by the small size. It was appeared that dissatisfaction rate of skirt was higher than that of blouse. The large part of dissatisfaction was appeared on waist circumference of blouse and hem circumference of skirt. The girls who experienced alterating the part of uniforms such as waist circumference of skirt, skirt length and hem circumference had high satisfaction rate. And a result of analyzing the level of satisfaction with uniforms-size-satisfaction/dissatisfaction showed the significant differences in fashion, factors-aesthetics and factors-activity of skirt and blouse.

• 한국재료학회지
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• 제20권10호
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• pp.550-554
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• 2010

This work presents a fabrication procedure to make large-area, size-tunable, periodically different shape metal arrays using nanosphere lithography (NSL) combined with ashing and annealing. A polystyrene (PS, 580 ${\mu}m$) monolayer, which was used as a mask, was obtained with a mixed solution of PS in methanol by multi-step spin coating. The mask morphology was changed by oxygen RIE (Reactive Ion Etching) ashing and temperature processing by microwave heating. The Au or Pt deposition resulted in size tunable nano patterns with different morphologies such as hole and dots. These processes allow outstanding control of the size and morphology of the particles. Various sizes of hole patterns were obtained by reducing the size of the PS sphere through the ashing process, and by increasing the size of the PS sphere through annealing treatment, which resulted in tcontrolling the size of the metallic nanoparticles from 30 nm to 230 nm.

• Journal of Korean Dental Science
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• 제12권1호
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• pp.20-28
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• 2019

Purpose: This study was performed to evaluate the effect of voxel size on the accuracy of landmark identification in cone-beam computed tomography (CBCT) images. Materials and Methods: CBCT images were obtained from 15 dry human skulls with two different voxel sizes; 0.39 mm and 0.10 mm. Three midline landmarks and eight bilateral landmarks were identified by 5 examiners and were recorded as three-dimensional coordinates. In order to compare the accuracy of landmark identification between large and small voxel size images, the difference between best estimate (average value of 5 examiners' measurements) and each examiner's value were calculated and compared between the two images. Result: Landmark identification errors showed a high variability according to the landmarks in case of large voxel size images. The small voxel size images showed small errors in all landmarks. The landmark identification errors were smaller for all landmarks in the small voxel size images than in the large voxel size images. Conclusion: The results of the present study indicate that landmark identification errors could be reduced by using smaller voxel size scan in CBCT images.

• 대한금속재료학회지
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• 제49권7호
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• pp.530-534
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• 2011

To analyze the effect of the pore size of graphite in a pore-forming agent, graphite was added to porous ceramics of $Al_2O_3-SiO_2-ZrO_2$ systems. The graphite had 45~75, 100~125, 150~180, and 75~180${\mu}m$ dimensions. The properties of the ceramics, such as apparent porosity, density, dynamic elastic modulus, mechanical strength, and permeability, were investigated. The average pore size increased from 15.35${\mu}m$ to 22.32${\mu}m$ with the increase of the graphite size. The sample with the largest average pore size showed the highest mechanical strength and gas permeability. This was due to the sample with the largest pore size at the same porosity having fewer pores and larger distance between the pores than the sample with the smallest pore size, making cracks less likely to propagate. In addition, the large pore size reduced the repulsive power originating from the drag force between the gas and internal pore walls.

• 대한가정학회지
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• 제50권7호
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• pp.37-48
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• 2012

The purpose of this study was conducted to improve middle and high school students' satisfaction on their uniforms and to provide basic information for their better size systems. This study analyzed the purchasing and modification behavior, fitting evaluation, and size decision aspect of students. This study was surveyed middle and high schools students in Daegu City. The collected data were analyzed by frequency analysis, percentage, t-test, chisquare test. The results of this study are as follows; 61.3% of the students interviewed have experienced to modify their uniforms. Since the unfittable size and non-fashionable design caused the students to modify their uniforms, it seems necessary to set up the various uniform sizes, as well as figuring out its aesthetic characteristic. Between middle school and high school students, and students with a uniform modification and students without a uniform modification, there were partially differences in fitting evaluation, and size decision.

• 수산해양교육연구
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• 제29권1호
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• pp.209-223
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• 2017

The purpose of this study is to compare and analyze science self-efficacy, science self-concept and scientific attitude according to the class size in the elementary school. For this purpose, three research questions were set as follows; First, are there any differences in science self-efficacy according to the class size? Second, are there any differences in science self-concept according to the class size? Third, are there any differences scientific attitude according to the class size? To solve this research questions, the subjects in this study were 809 5th and 6th grade students of eight elementary schools in Busan. 220 were sampled from small-size classes, 354 from mid-size classes and 235 from large-size classes. The results of this study through the process are as follows; First, there were significant differences in science self-efficacy according to the class size. Second, there were significant differences in science self-concept according to the class size. Third, according to the result, there was not a significant difference in scientific attitude according to the class size. The findings of the study suggest that it is necessary the class size should be adjusted to the appropriate level for improving student's science self-efficacy and science self-concept.

• Journal of Yeungnam Medical Science
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• 제36권2호
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• pp.115-123
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• 2019

Background: This study aimed to assess the in-field lymph node (LN) failure rate according to LN size and to investigate effect of LN size on the survival outcome of patients with locally advanced cervical carcinoma treated with concurrent chemoradiotherapy (CCRT). Methods: A total of 310 patients with locally advanced cervical carcinoma treated with CCRT were enrolled in retrospective study. LN status was evaluated by magnetic resonance imaging. All patients received conventional external beam irradiation and high-dose rate brachytherapy, and concurrent cisplatin-based chemotherapy. In-field LN failure rate according to LN size was analyzed. Results: The median follow-up period was 83 months (range, 3-201 months). In-field LN failure rate in patients with pelvic LN size more than 10 mm was significantly higher than that in patients with pelvic LN size less than 10 mm (p<0.001). A similar finding was observed in the infield para-aortic LN (PALN) failure rate (p=0.024). The pelvic and PALN size (${\geq}10mm$) was a significant prognostic factor of overall-survival (OS) and disease-free survival rate in univariate and multivariate analyses. The OS rate was significantly different between groups according to LN size (<10 mm vs. ${\geq}10mm$). Conclusion: A LN of less than 10 mm in size in an imaging study is controlled by CCRT. On the other hand, in LN of more than 10 mm in size, the in-field LN failure rate increase and the prognosis deteriorate. Therefore, a more aggressive treatment strategy is needed.

• Journal of Mechanical Science and Technology
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• 제18권2호
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• pp.253-261
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• 2004

A simple and effective filtering method to control the member size of an optimized structure is proposed for topology optimization. In the present approach, the original objective sensitivities are replaced with their relative values evaluated within a filtering area. By adjusting the size of the filtering area, the member size of an optimized structure or the level of its topological complexity can be controlled even within a given finite element mesh. In contrast to the checkerboard-free filter, the present filter focuses on high-frequency components of the sensitivities. Since the present filtering method does not add a penalty term to the objective function nor require additional constraints, it is not only efficient but also simple to implement. Mean compliance minimization and eigenfrequency maximization problems are considered to verify the effectiveness of the present approach.

• 한국분무공학회지
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• 제19권4호
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• pp.174-181
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• 2014

This study investigates the effects of nanoparticle size and temperature on the thermal conductivity enhancement of water-based alumina ($Al_2O_3$) nanofluids, using the centrifuging method and relative centrifugal forces of differing magnitude to produce nanofluids of three different particles without involving any dispersants or surfactants. We determined the coupling dependency in thermal conductivity enhancement relative to nanoparticle size and temperature of the alumina nanofluids and also experimentally showed that the effect of temperature on thermal conductivity is strongly dependent on nanoparticle size. Also, our experimental data presented that the effective medium theory models such as the Maxwell model and Hasselman and Johnson model are not sufficient to explain the thermal conductivity of nanofluids since they cannot account for the temperature- and size-dependent nature of water-based alumina nanofluids.