• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1747-1751
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• 2008

Electrohydrodynamic jet printing (EHDP) technique is widely used for the direct writing. However, in the existing EHDP method, the printing characteristics are affected by the printing substrate used, and the line width of the printed is determined by the geometry of the nozzle. We propose an EHDP method which is capable of (1) removing the effect from the substrate, and (2) controlling the line width through the ON/OFF control of the each nozzle in the nozzle array. Printing characteristics of our EHDP system were examined and successful ON/OFF control of the nozzle array were demonstrated. By using the proposed EHDP, it is expected that stable meniscus regardless of the substrate and different line widths even using the same nozzle can be achieved.

• 한국정밀공학회지
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• 제22권1호
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• pp.199-206
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• 2005

Mask manufacturing is a high COC and COO process in developing of semiconductor devices because of mask production tool with high resolution. Direct writing has been thought to be the one of the patterning method to cope with development or small-lot production of the device. This study consists two categories. One is the additional process of the direct and maskless patterning generation using SLA for easy and convenient application and the other is a removal process using wet-etching process. In this study, cured status of epoxy pattern is most important parameter because of the beer-lambert law according to the diffusion of UV light. In order to improve the contact force between patterns and substrate, prime process was performed and to remove the semi-cured resin which makes a bad effects to the pattern, spin cleaning process using TPM was also performed. At a removal process, contact force between photo-curable resin as an etching mask and Si wafer is important parameter.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1179-1180
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• 2005

3D micro scaled shapes are fabricated with the method of direct writing and superposing grooving in ambient air using femto-second laser pulses and copper, aiming at establishing an industrially useful femto-second laser processing machine to be able to fabricate three dimensional micro-scale structures, especially micro scaled molds, and processing techniques. For the several advantages, there is no thermally influenced region around the area irradiated by the laser beam and surfaces irradiated laser beam are smooth and substances ablated to form are no attached on the surface of works and so on, the femto-second laser technology is anticipated for advanced micro/nano precision technology.

• Macromolecular Research
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• 제13권5호
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• pp.435-440
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• 2005

This study describes a method where the match of two different length scales, i.e., the patterns from self-assembled block copolymer (<50 nm) and electron beam writing (>50 nm), allow the nanometer scale pattern mask. The method is based on using block copolymers containing a poly(methyl methacrylate) (PMMA) block, which is subject to be decomposed under an electron beam, as a pattern resist for electron beam lithography. Electron beam on self assembled block copolymer thin film selectively etches PMMA microdomains, giving rise to a polymeric nano-pattern mask on which subsequent evaporation of chromium produces the arrays of Cr nanoparticles followed by lifting off the mask. Furthermore, electron beam lithography was performed on the micropatterned block copolymer film fabricated by micro-imprinting, leading to a hierarchical self assembled pattern where a broad range of length scales was effectively assembled, ranging from several tens of nanometers, through submicrons, to a few microns.

• 한국산업융합학회 논문집
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• 제26권4_1호
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• pp.517-527
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• 2023

Many techniques have been proposed and investigated for microlens array manufacturing in three-dimensional (3D) structures. We present fabricating a microlens array using selective laser etching and a CO₂ laser. The femtosecond laser was employed to produce multiple micro-cracks that comprise the predesigned 3D structure. Subsequently, the wet etching process with a KOH solution was used to produce the primary microlens array structures. To polish the nonoptical surface to the optical surface, we performed reflow postprocessing using a CO₂ laser. We confirmed that the micro lens array can be manufactured in three primary shapes (cone, pyramid and hemisphere). Compared to our previous study, the processing time required for laser processing was reduced from approximately 1 hour to less than 30 seconds using the proposed processing method. Therefore, micro lens arrays can be manufactured using our processing method and can be applied to mass productionon large surface areas.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제18권1호
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• pp.58-65
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• 2007

Objectives : Motivational factor is a unique contributor to the typically poor academic performance of children with ADHD. However, few study has directly intervened learning motivation in children with ADHD. We conducted this study to explore the direct effects of the learning motivation improvement program applied to children with ADHD. Method The program was designed in order to increase an interest-inducing educational intervention, an academic skills integration, a basic learning activity (reading, writing, and math), and children's self-esteem. We conducted the program twice a week (total 10 sessions) and assessed learning motivation, teaming attitude, self-esteem, academic performance, and problem behaviors of participating children. Results : After the program, teachers reported improvement in teaming motivation. In addition, parents notified sisnificant reduction of problem behaviors. Children reported improvement in a few domains of teaming motivation and learning attitude. Conclusion : While loaming motivation is regarded as an important factor in education, there have been few studies considering this issue in both educational and psychiatric fields. The teaming motivation improvement would be needed in both field in order to reduce the deficits in academic performance in children with ADHD.

• 제어로봇시스템학회논문지
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• 제21권6호
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• pp.583-588
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• 2015

Flexible tactile sensors can provide valuable feedback to intelligent robots regarding the environment around them. This is especially important when robots such as, service robots share a workspace with humans. This paper presents a contact force measurement algorithm of a flexible tactile sensor. This sensor is manufactured by a direct-writing technique, which is one 3D printing method, using multi-walled carbon nano-tubes. An analog signal processing circuit has been designed and implemented to reduce noise contained in the sensor output. In addition, a digital version of the Butterworth filter was implemented by software running on a microcontroller. Through various experiments, characteristics of the sensor system have been identified. Based on three traits, an algorithm to detect the contact and measure the contact force has been developed. The entire system showed a promising prospect to detect the contact over a large and curved area.

• 한국실내디자인학회논문집
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• 제17권6호
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• pp.120-127
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• 2008

Korean space design image is a kind of writing as well as one of the sign that dissembles itself as a direct transcript of what it represents. Moreover it is pictorial representation and notions such as mental and perceptual imaginary. Significance of Iconology lies in how we transform image and the imagination that produces it into power of trust and respect. From this point of view, the process of this study is illustrated as follows: At first, this study search out concept of archetype, collective unconsciousness and collective representation that found principles on basic theory for interpretation of korean space icon. Secondly, it mentions theoretical background of iconological contents and structure. And it clarifies Iconology as a method that is applicable logic for Korean space design. Finally, as an analysis of korean space design, this study analyse in three steps that are pre-iconological description, iconological analysis, iconological interpretation each in terms of modernization at regional korean space design. In the step of the pre-iconological description, it describe visual representative style based on era and place. In the step of the iconological analysis, the typical structure is classified in status, vernacular, ethnic, traditional. In the step of the iconological interpretation, connotation is categorized into allegory, multivalence, potential. Through this process, this study suggest that iconology is an appropriate analysis system of Korean space design images that represent symbols combined with our collective emotion.

• 영어어문교육
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• 제15권3호
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• pp.33-57
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• 2009

Taking the issues of inequity and power between NES and NNES teachers as a starting point, this qualitative study explores the way the widespread belief of the native speaker fallacy manifests itself in one NNES teacher's teaching life and is linked to the teacher's understanding of herself as an English teacher. Guided by critical applied linguistics (Pennycook, 2001) and using Bourdieu's (1991) theorization of symbolic violence, I conducted an instrumental case study (Stake, 1995) in an ESL writing class at a US university. I collected data through classroom observations and interviews over a nine-month period and analyzed the data using the constant comparison method (Glaser and Strauss, 1967). The findings illustrate the ways the dominant ideology of the native speaker fallacy works to maintain and reproduce the status quo unequal relation between NES and NNES teachers by making all parties involved believe in the artificial sociocultural arrangements that favor NES teachers as legitimate. The findings direct our attention to the importance of critical teacher education that will enable future TESOL professionals to engage in critical reflection on diverse issues and envision transformative change. The findings, in particular, point to the need for language support for NNES teachers in TESOL teacher education.

• 한국정밀공학회지
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• 제31권2호
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• pp.149-156
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• 2014

Flexible tactile sensors can provide valuable feedback to intelligent robots about the environment. This is especially important when the robots, e.g., service robots, are sharing the workspace with human. This paper presents a flexible tactile sensor that was manufactured by direct writing technique, which is one of 3D printing method with multi-walled carbon nano-tubes. The signal processing system consists of two parts: analog circuits to amplify and filter the sensor output and digital signal processing algorithms to reduce undesired noise. Finally, experimental setup is implemented and evaluated to identify the characteristics of the flexible tactile sensor system. This paper showed that this type of sensors can detect the initiation and termination of contacts with appropriate signal processing.