• International journal of advanced smart convergence
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• 제10권1호
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• pp.159-165
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• 2021

Electronic devices used in the mobile environments fabricated under the plasma conditions in high vacuum system. Especially for the development of advanced electronic devices, high quality plasma as the process conditions are required. For this purpose, the variable conductance throttle valves for controllable plasma employed to the high vacuum system. In this study, we analyzed the effects of throttle valve applications on vacuum characteristics simulated to obtain the optimum design modelling for plasma conditions of high vacuum system. We used commercial simulator of vacuum system, VacSim(multi) on this study. Reliability of simulator verified by simulation of the commercially available models of high vacuum system. Simulated vacuum characteristics of the proposed modelling agreed with the observed experimental behaviour of real systems. Pressure limit valve and normally on-off control valve schematized as the modelling of throttle valve for the constant process-pressure of below 10-3 torr. Simulation results plotted as pump down curve of chamber, variable valve conductance and conductance logic of throttle valve. Simulated behaviors showed the applications of throttle valve sustained the process-pressure constantly, stably, and reliably in plasma process.

• 한국기계가공학회지
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• 제21권7호
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• pp.1-9
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• 2022

Peeling and dimensional deformation that occur during a manufacturing process are accompanied by an increase in the manufacturing cost and production time caused by manufacturing defects. In order to solve this problem, it is essential to predict risk factors at the design stage through computational analysis of the additive manufacturing process and to control shape distortion due to residual stress. In this study, the dimensional characteristics were improved by applying the distortion compensation design through computational analysis to minimize the distortion occurring in the DMLS(Direct Metal Laser Sintering) method of the metal additive manufacturing process.

• 대한지구과학교육학회지
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• 제3권3호
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• pp.239-247
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• 2010

The purpose of this study is to examine the effects of an free inquiry method based on PBL(Problem-Based Learning: PBL) to improve students science process skills and self-directed learning characteristics. To verify this research, twenty-two third-grade students were selected from Chung-ryeol Elementary School located in Busan. They have received pre-test and post-test about their abilities in their science process skills and abilities for self-directed learning characteristics. Also, their self-reflection data was analyzed. The teaching and learning PBL process is to provide the information named 'I am the expert on Earth and Moon' which is recreated by analyzing the science curriculum and characteristics of students from Lesson 3 'Earth and Moon', and to make plans for solving the information with K/NK method. Then, to solve the information is gathered and investigated using the PBL workbook. Lastly, students present their finding using the free inquiry method in a group. The post-test showed following results : first, the free inquiry method based on PBL stimulates inquisitiveness in students about science learning and the research group shows improved science process skill. It shows us that using the free inquiry method based on PBL can be used effects to elevate science process skill. Second, the free inquiry method based on PBL has a positive effect on self-directed learning. The research tells us that using the free inquiry method based on PBL can improve a student self-directed learning characteristics.

• 한국분말재료학회지
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• 제22권2호
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• pp.87-92
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• 2015

Metallic porous materials have many interesting combinations of physical and geometrical properties with very low specific weight or high gas permeability. In this study, highly porous Cu foam is successfully fabricated by a slurry coating process. The Cu foam is fabricated specifically by changing the coating amount and the type of polyurethane foam used as a template. The processing parameters and pore characteristics are observed to identify the key parameters of the slurry coating process and the optimized morphological properties of the Cu foam. The pore characteristics of Cu foam are investigated by scanning electron micrographs and micro-CT analyzer, and air permeability of the Cu foam is measured by capillary flow porometer. We confirmed that the characteristics of Cu foam can be easily controlled in the slurry coating process by changing the microstructure, porosity, pore size, strut thickness, and the cell size. It can be considered that the fabricated Cu foams show tremendous promise for industrial application.

• 한국컴퓨터정보학회논문지
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• 제12권4호
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• pp.201-207
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• 2007

제조업에서는 2개 이상의 상관이 있는 품질특성치를 동시에 감시하거나 관리를 하기 위한 필요성이 많이 제기되고 있다. 하지만 복수의 품질특성치를 각각 독립적으로 감시하면 판단의 오류가 발생될 수 있다. 복수의 품질특성치를 동시에 감시하고자 할 때 $X^2$ 또는 $T^2$와 같은 다변량 관리도가 사용되어질 수 있다. 본 논문에서는 다수의 품질특성치를 갖는 용해공정에서 조기에 이상 징후를 파악하기 위하여 다변량 관리도를 이용한 조기경보 시스템을 구현하였다. 용해공정에서 상관성이 있는 다수의 품질특성치를 동시에 관리하기 위해 개발된 이 모듈은 용해공정의 통계적 공정관리 활동에 효율성 및 효과성을 향상시켜 주었다.

• 복식
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• 제59권8호
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• pp.152-165
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• 2009

The purpose of this study was to expand the expression of Fashion Illustration using Lenticular imaging process. In the 2-dimensional pictures, Lenticular imaging process can be effective to make multiple, virtual and variable images, which are assumed the main characteristics of modern Fashion Illustration. For this study, the main characteristics of digital based fashion trend and Fashion Illustration were analyzed. The main characteristics of digital based fashion were 'Interaction, Variableness, Virtuality, Multiples and Hyper-text' which were related with Simulacre thinking. The main characteristics of expression in Fashion Illustration were 'Virtuality and Multiples'. The image of 'Variableness' was an important factor in digital based fashion, but it was restricted within Fashion Illustration because of the 2-dimensional picture. Therefore, the Lenticular imaging process was proposed as an effective method to expand 2-dimensional limit, giving an effect of 'Variableness' in Fashion Illustration. Based on this study, 5 illustration works were proposed. The Lenticular imaging process was applied in making the images of 'Virtuality, Multiples and Variableness' in 5 works. The result of this study can be a basic material to understand the characteristics of modern Fashion Illustration as a meaningful sub-culture, and diverse expressions corresponding with the phases of the times.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 추계학술발표대회 개요집
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• pp.211-212
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• 2004

Characteristics of the wear resistance thermal sprayed coatings was investigated in order to determine proper coating process. Hardness evaluation and microstructural observation were conducted to find relationship between coating characteristics and its wear performance. It was found that HVOF process would give better properties than arc thermal process in terms of hardness and adhesion strength which resultantly determine wear performance of the coatings.

• 한국기계가공학회지
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• 제21권6호
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• pp.50-59
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• 2022

The design of the substrate significantly affects the thermal history and the residual stress formation in the vicinity of a repaired region by a directed energy deposition (DED) process. The occurrence of defects in the repaired region depends on the thermal history and residual stress formation. The objective of this study was to investigate the influence of the inclined angle and depth of the substrate on the thermal and residual stress characteristics in the vicinity of a repaired region by a DED process through two-dimensional finite element analyses (FEAs). The temperature and residual stress distributions in the vicinity of the repaired region were predicted according to the combination of the inclined angle and depth of the substrate. The effects of the inclined angle and depth on the depth of the heat affected zone and the maximum value of the residual stress were examined. A proper combination of the inclined angle and depth of the substrate was estimated to decrease the residual stress in the vicinity of the repaired region.

• 전기학회논문지P
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• 제65권1호
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• pp.57-65
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• 2016

This paper was analyzed the characteristics of piezoelectric inkjet print head using finite element method(FEM). It showed the bending node driving of piezoelectric and relation theory principle consider piezoelectric material characteristics and ink characteristics. From such result we were had the piezoelectric head design and manufacture. It got a this head characteristics through experiment, we confirmed that proper voltage control is possible to through ink drop control experiment of piezoelectric print head. This paper was obtained the suitable ink jetting characteristics that manufacture the control circuit and piezoelectric inkjet print head. This practice product was applied to improvement of PCB electric circuit pattern by etching resist ink that PCB manufactured to complex process over traditional 6 stages can be simpled to 1 stage by inkjet printing technology.

• 기술혁신연구
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• 제8권1호
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• pp.155-172
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• 2000

Management control is the process by which managers ensure that resources are obtained and used effectively and efficiently in achieving the organization's objectives. This paper explores relationships between characteristics of R&D and management control. R&D characteristics measured in this research include the degree of technological uncertainty and the measurability of outputs. Management control was classified and categorized into observable dimensions of control such as behavior, budget, process, results and personnel control. The relationships were tested with questionnaire survey data from a sample of 206 principal investigators(PIs) in the thirteen Government supported research institutes(GSRIs) in Korea. There are significant negative relations between the degree of technological uncertainty and budget, process and personnel control, and significant positive relations between the measurability of outputs and process, results and personnel control. These results indicate that the relations between task characteristics and management control in R&D are different from those to be found in other activities of organizations.