• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.689-693
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• 2005

Inkjet printing is a non-contact and direct writing associated with a computer. In the industrial field, there have been many efforts to utilize the inkjet printing as a new way of manufacturing, especially for electronic devices. For the application of inkjet printing to electronic field, one of the key factors is exact realization of designed images into printed patterns. In this work, micro patterning for conducting line has been studied using the piezoelectric print head and silver nano ink. Dimensions of printed images have been predicted in terms of print resolution and diameter of a single dot. The predicted and the measured values showed consistent results. Using the results, the design capability for industrial inkjet printing could be achieved.

• Laser Solutions
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• v.10 no.2
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• pp.5-15
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• 2007

A new printing process for LCD color filter is proposed in this work by using the localized laser heating, which is called laser-induced spray printing (LISP) process. The LISP is a non-contact process, which injects the ink from the donor substrate to the glass substrate by the bubble pressure induced by laser heating. The temperature distribution of the donor substrate is calculated numerically to explain the ink ejection phenomena. The composition of the ink was includes the red pigment, n-butanol, xylene, BCA and epoxy. Experiments were conducted by using the fiber laser system, and the color filter patterns were deposited successfully under the proper laser heating conditions.

• Journal of Korean language education
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• v.28 no.1
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• pp.141-171
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• 2017

This study investigates Korean language teachers' perception/beliefs and practices in written feedback. Two types of data were collected: (1) teachers' feedback on three compositions by elementary-level learners, and (2) a survey questionnaire. The result showed that teachers perceived written feedback to be important even though they had not enough opportunities to receive appropriate training. Lack of training brought about limited feedback in terms of both quantity and quality, and inconsistency between their beliefs and practice. This study closes with the needs for teacher training and further studies on teachers' feedback practices.

• Korean Journal of Materials Research
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• v.34 no.3
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• pp.144-151
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• 2024

This work focuses on the fabrication of excellent magnetic structures for trapping breast cancer cells. Micromagnetic structures were patterned for trapping cancer cells by depositing 30 nm of permalloy on a silicon substrate. These structures were designed and fabricated using two fabrication techniques: electron beam lithography and laser direct writing. Two types of magnetic structures, rectangular wire and zig-zagged wire, were created on a silicon substrate. The length of each rectangular wire and each straight line of zig-zagged wire was 150 ㎛ with a range of widths from 1 to 15 ㎛ for rectangular and 1, 5, 10 and 15 ㎛ for zigzag, respectively. The magnetic structures showed good responses to the applied magnetic field despite adding layers of silicon nitride and polyethylene glycol. The results showed that Si + Si₃N₄ + PEG exhibited the best adhesion of cells to the surface, followed by Si + Py + Si₃N₄ + PEG. concentration of 5-6 with permalloy indicates that this layer affected silicon nitride in the presence of Polyethylene glycolPEG.

• Journal of radiological science and technology
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• v.36 no.2
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• pp.99-110
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• 2013

In the medical field, the necessity of education growth for the professional Radiation Technologists has been emphasized to become experts on radiation and the radiation field is important of the society. Also, in hospitals and companies, important on thesis is getting higher in order to active and cope with rapidly changing internal and external environment and a more in-depth expert training, the necessity of new teaching and learning model that can cope with changes in a more proactive has become. Thesis writing classes brought limits to the in-depth learning as to start a semester and rely on only specific programs besides, inevitable on passive participation. In addition, it does not have a variety opportunity to present, an actual opportunity that can be written and discussed does not provide much caused by instructor-led classes. As well as, it has had a direct impact on the quality of the thesis, furthermore, having the opportunity to participate in various conferences showed the limitations. In order to solve these problems, in this study, writing thesis has organized training operations as a consistent gradual deepening of learning, at the same time, the operational idea was proposed based on the connectivity integrated operating and effective training program & instructional tool for improving the ability to perform the written actual thesis. The development of teaching and learning model consisted of 4 system modeling, scaffolding, articulation, exploration. Depending on the nature of the course, consisting team following the personal interest and the topic allow for connection subject, based on this, promote research capacity through a step-by-step evaluation and feedback and, fundamentally strengthen problem-solving skills through the journal studies, help not only solving the real-time problem by taking wiki-space but also efficient use of time, increase the quality of the thesis by activating cooperation through mentoring, as a result, it was to promote a positive partnership with the academic. Support system in three stages planning subject, progress & writing, writing thesis & presentation and based on cognitive apprenticeship. The ongoing Coaching and Reflection of professor and expert was applied in order to maintain these activities smoothly. The results of this study will introduce actively, voluntarily and substantially join to learners, by doing so, culture the enhancement of creativity, originality and the ability to co-work and by enhance the expertise of based-knowledge, it is considered to be help to improve the comprehensive ability.

• Macromolecular Research
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• v.17 no.3
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• pp.197-202
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• 2009

Solution-based, direct-write patterning by an automated, computer-controlled, inkjet technique is of particular interest in a wide variety of industrial fields. We report the construction of three-dimensional (3D), micro-patterned structures by polymer inkjet printing. A piezoelectric, drop-on-demand (DOD) inkjet printing system and a common polymer, PVA (poly(vinyl alcohol)), were explored for 3D construction. After a systematic preliminary study with different solvent systems, a mixture of water and DMSO was chosen as an appropriate solvent for PVA inks. The use of water as a single solvent resulted in frequent PVA clogging when the nozzles were undisturbed. Among the tested polymer ink compositions, the PVA inks in a water/DMSO mixture (4/1 v/v) with concentrations of 3 to 5 g/dL proved to be appropriate for piezoelectric DOD inkjet printing because they were well within the proper viscosity and surface tension range. When a dot was printed, the so-called 'coffee-ring effect' was significant, but its appearance was not prominent in line printing. The optimal polymer inkjet printing process was repeated slice after slice up to 200 times, which produced a well-defined, 3 D micro-patterned surface. The overall results implied that piezoelectric DOD polymer inkjet printing could be a powerful, solid-freeform, fabrication technology to create a controlled 3D architecture.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.18 no.1
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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.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.6
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.590-595
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• 2004

The shape and size variations of the nanopatterns produced on a positive photoresist using a near-field scanning optical microscope(NSOM) are investigated with respect to the process variables. A cantilever type nanoprobe having a 100nm aperture at the apex of the pyramidal tip is used with the NSOM and a He-Cd laser at a wavelength of 442nm as the illumination source. Patterning characteristics are examined for different laser beam power at the entrance side of the aperture( $P_{in}$ ), scan speed of the piezo stage(V), repeated scanning over the same pattern, and operation modes of the NSOM(DC and AC modes). The pattern size remained almost the same for equal linear energy density. Pattern size decreased for lower laser beam power and greater scan speed, leading to a minimum pattern width of around 50nm at $P_{in}$ =1.2$\mu$W and V=12$\mu$m/. Direct writing of an arbitrary pattern with a line width of about 150nm was demonstrated to verify the feasibility of this technique for nanomask fabrication. Application on high-density data storage using azopolymer is discussed at the end.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.71-71
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• 2003

Hot embossing has been widely accepted as an alternative to photolithography in generating patterns on polymeric substrates. The optimization of embossing process should be accomplished based on polymer substrate materials. In this paper, the effect of polymer substrates on nano scale hot embossing process was studied. Silicon molds with nano size patterns were fabricated by e-beam direct writing. Molds were coated with self-assembled monolayer (SAM) of (1, 1, 2.2H -perfluorooctyl)-trichlorosilane to reduce the stiction between mold and substrates. For an embossing, pressure of 55, 75 bur, embossing time of 5 min and temperature of above transition temperature were peformed. Polymethylmethacrylates (PMMA) with different molecular weights of 450,000 and 950,000, MR-I 8010 polymer (Micro Resist Technology) and polyaliphatic imide copolymer were applied for hot embossing process development in nano size. These polymers were spun coated on the Si wafer with the thickness between 150 and 200 nm. The nano size patterns obtained after hot embossing were observed and compared based on the polymer properties by scanning electron microscopy (SEM). The imprinting uniformity dependent on the Pattern density and size was investigated. Four polymers have been evaluated for the nanoimprint By optimizing the process parameters, the four polymers lead to uniform imprint and good pattern profiles. A reduction in the friction for smooth surfaces during demoulding is possible by polymer selection.