• Journal of Technologic Dentistry
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• v.33 no.4
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• pp.299-306
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• 2011

Purpose: This study aimed to investigate the shear bond strength by manufacturing the veneering porcelain on the IPS e.max $ZirCAD^{(R)}$ zirconia core, using the layering technique and heat-pressing technique, and to evaluate the clinical stability by comparing to the conventional metal ceramic system. Methods: The Schmitz-Schulmeyer test method was used to evaluate the core-veneer shear bond strength of zirconia core ceramic(IPS e.max $ZirCAD^{(R)}$) and their manufacture recommended two veneering ceramic systems(IPS e.max $ceram^{(R)}$, IPS e. max $ZirPress^{(R)}$). A metal ceramic system(Bellabond $plus^{(R)}$, VITA $VM13^{(R)}$) was used as a control group for the two all ceramic system test groups. The maximum loading and shear bond strength was measured. The average shear strength(MPa) was analyzed with the one-way ANOVA and the Tukey's test(${\alpha}$=.05). The fracture specimens were examined using Microscope to determine the failure pattern. Results: The mean shear bond strengths(SD) in MPa were MBSB control 43.62(2.13); ZBSB 18.65(1.76); ZPSB 18.89(1.54). The shear strengths of the zirconia cores were not significantly different(P>.05). Microscope examination showed that zirconia specimens presented mixed failure, and base metal alloy specimens showed adhesive failure. Conclusion: There was no siginificant different between the layering technique and the heat pressing technique in the veneering methods on the zirconia cores. None of the zirconia core and veneering ceramics could attain the high bond strength values of the metal ceramic combination.

• Journal of the Korean earth science society
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• v.43 no.4
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• pp.557-566
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• 2022

The purpose of this study was to examine the status of the field application of the Science II career electives with the application of the 2015 revised curriculum up to the 3rd year of high school. This study focused on examining high school science teachers' perceptions of the student-participatory class and process-centered assessment in Science II subjects, which are career-intensive high school science electives. A total of 192 science teachers responded to the survey questionnaire, and 12 teachers participated in interviews. In the in-depth interviews conducted to supplement the survey results, questions were asked about changes in the overall class, the status of student-participatory classes, and changes in the assessment of Science II subjects due to the emphasis on process-centered assessment. The main research results included teachers' perceptions of changes in teaching and assessment methods with the application of the revised curriculum, the degree to which the eight skills used in Science II classes develop the key competencies of science, and the teaching and assessment methods commonly used in Science II classes. Science teachers generally agreed with the purpose and necessity of introducing student-participatory classes and process-centered assessment, which are the core purpose of the 2015 revised curriculum. However, they had difficulties in practice due to the excessive content of Science II subjects. Problems were also encountered with securing objectivity and fairness during assessments and the operation of online science classes due to COVID-19.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.1
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• pp.1-7
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• 2009

This paper describes design of high energy efficiency 32 bit parallel processor core using instruction-levels data gating and dynamic voltage scaling (DVS) techniques. We present instruction-levels data gating technique. We can control activation and switching activity of the function units in the proposed data technique. We present instruction-levels DVS technique without using DC-DC converter and voltage scheduler controlled by the operation system. We can control powers of the function units in the proposed DVS technique. The proposed instruction-levels DVS technique has the simple architecture than complicated DVS which is DC-DC converter and voltage scheduler controlled by the operation system and a hardware implementation is very easy. But, the energy efficiency of the proposed instruction-levels DVS technique having dual-power supply is similar to the complicated DVS which is DC-DC converter and voltage scheduler controlled by the operation system. We simulate the circuit simulation for running test program using Spectra. We selected reduced power supply to 0.667 times of the supplied power supply. The energy efficiency of the proposed 32 bit parallel processor core using instruction-levels data gating and DVS techniques can improve about 88.4% than that of the 32 bit parallel processor core without using those. The designed high energy efficiency 32 bit parallel processor core can utilize as the coprocessor processing massive data at high speed.

• Computers and Concrete
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• v.27 no.4
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• pp.369-383
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• 2021

This article deals with the frequency analysis of viscoelastic sandwich disk with graphene nano-platelets (GPLs) reinforced viscoelastic concrete (GPLRVC) face sheets and honeycomb core. The honeycomb core is made of aluminum due to its low weight and high stiffness. The rule of the mixture and modified Halpin-Tsai model are engaged to provide the effective material constant of the concrete. By employing Hamilton's principle, the governing equations of the structure are derived and solved with the aid of the Generalize Differential Quadrature Method (GDQM). In this paper, viscoelastic properties are modeled according to Kelvin-Voigt viscoelasticity. The deflection as the function of time can be solved by the fourth-order Runge-Kutta numerical method. Afterward, a parametric study is carried out to investigate the effects of the outer to inner radius ratio, hexagonal core angle, thickness to length ratio of the concrete, the weight fraction of GPLs into concrete, and the thickness of honeycomb core to inner radius ratio on the frequency of the viscoelastic sandwich disk with honeycomb core and FG-GPLRVC face sheet.

• Structural Engineering and Mechanics
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• v.91 no.1
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• pp.75-86
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• 2024

In this paper, the porous metal PM-35 is proposed as the filler material of filled thin-walled tubes (FTTs), and a series of experimental study is conducted to investigate the dynamic behavior and energy absorption performance of PM-35 filled thin-walled tubes under impact loading. Firstly, cylinder solid specimens of PM-35 steel are tested to investigate the impact mechanical behavior by using the Split Hopkinson pressure bar set (SHP); Secondly, the filled thin-walled tube specimens with different geometric parameters are designed and tested to investigate the feasibility of PM-35 steel applied in FTTs by the orthogonal test. According to the results of this research, it is concluded that PM-35 steel is with the excellent characteristics of high energy absorption capacity and low yield strength, which make it a potential filler material for FTTs. The micron-sizes pore structure of PM-35 is the main reason for the macroscopic mechanical behavior of PM-35 steel under impact loading, which makes the material to exhibit greater deformation when subjected to external forces and obviously improve the toughness of the material. In addition, PM-35 steel core-filled thin-wall tube has excellent energy absorption ability under high-speed impact, which shows great application potential in the anti-collision structure facilities of high-speed railway and maglev train. The parameter V0 is most sensitive to the energy absorption of FTT specimens under impact loading, and the sensitivity order of different variations to the energy absorption is loading speed V0>D/t>D/L. The loading efficiency of the FTT is affected by its different geometry, which is mainly determined by the sleeve material and the filling material, which are not sensitive to changes in loading speed V0, D/t and D/L parameters.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.2
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• pp.78-83
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• 2016

The development of an exclusive 8-axis multi-tasking machine to finish multiple cutting processes by a single piece of power equipment for securing the high-precision machining and high productivity of the series of shafts (a core part of the automotive powertrain that delivers engine power) is needed. The rigidity of the structure must be improved and the weight of the structure must be reduced to develop a multi-tasking machine with high precision and high productivity. In this paper, we perform a static structural analysis of the initial design of the multi-tasking machines and compare the results of the multi-tasking machines improved by the reinforced design and the results of the initial one. According to the results of the structural analysis, the rigidity of the reinforced machine was increased and the overall weight was decreased. Therefore, the productivity was increased.

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.479-494
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• 2004

The study was designed to forecast and derive future core technologies using Delphi method for Korean livestock industry. The technologies will make livestock industJy a core and strategic industry that has high value-added sector in 21 century. Questions were given to specialists of each technology in order to survey importance, realization time. level of R&D in Korea and foremost countries, leading group of R&D, effective policy, etc. for each technology. The target of the survey for Delphi is confined to specialists in the area of Animal Science and Veterinary Medicine. 90 core technologies were derived and 62 specialists answered the questionnaire.

• Korean Journal of Chemical Engineering
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• v.35 no.12
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• pp.2379-2383
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• 2018

We report a facile one-pot aqueous-phase synthesis of PdAu bimetallic nanoparticles with different Pd/Au ratio. The synthesis was conducted by co-reduction of Pd and Au precursor using ascorbic acid as a reducing agent and in the presence of polyallylamine hydrochloride (PAH). By high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and energy-dispersive X-ray spectrometry (EDS) analyses, we found that the synthesized nanoparticles had an onion-like core/shell/shell/shell structure with Au-rich core, Pd-rich shell, Au-rich shell, and Pd shell, respectively. We also investigated the catalytic performance of the synthesized PdAu nanoparticles toward hydrogen peroxide generation reaction.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.2
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• pp.556-565
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• 2015

The purpose of this study is to research on founding of the department of marine leisure industry in fisheries high school. Research methods were used a survey district, students and teachers in fisheries high school and industry human are 353 people in the target. The results of this research are as follows. First, the ratio in favor of making the marine leisure industrial department had more than 81%. The second, teachers and industry people selected core factors include oceanography, water leisure, leisure diving, commercial diving, lifeguard, rafting. Finally, subject for the department of marine leisure industry in fisheries high school are fisheries shipping industry basis, understanding of the ocean, marine leisure tourism, underwater technology, navigation, seamanship, maritime laws regulations, heat engines and aquatic organism.

• Asian Journal of Business Environment
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• v.7 no.2
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• pp.17-20
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• 2017

Purpose - This paper will go deep into the analysis of Korean Cultural industry development, and the result of the analysis shows that the cultural value of cultural product, competitive product lines and mature Market Mechanism are core competences of Korean Cultural industry. Research design, data, and methodology - This is a case study in the era of knowledge based economy, Cultural industry has become a new increasing point of economic development. Cultural industry, commonly regarded as an industry with high-ended value, is occupying more important role in economic development and social welfare promotion process. Results - Moreover the increasingly important role of cultural industry will hopefully help to promote industrial upgrading process and finally become a driving force for economic growth and technological innovation. During the process of cultural development, improving core competence of Cultural industry is a key consideration to help the development of Cultural industry in a positive way. Conclusions - From the study above, we find that in order to ensure sustainable development of Cultural industry, emphasis should be put on finding and improving core competence. Core competence of Korean Cultural industry is important and inspiring to the development of Chinese Cultural industry and regional integration in the East Asian area.