• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.49-49
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• 2010

Nanopiezotronics is an emerging area of nanotechnology with a variety of applications that include piezoelectric field-effect transistors and diodes, self-powered nanogenerators and biosystems, and wireless nano/biosensors. By exploiting coupled piezoelectric and semiconducting characteristics, it is possible for nanowires, nanobelts, or nanorods to generate rectifying current and potential under external mechanical energies such as body movement (handling, winding, pushing, and bending) and muscle stretching, vibrations (acoustic and ultrasonic waves), and hydraulic forces (body fluid and blood flow). Fully transparent, flexible (TF) nanogenerators that are operated by external mechanical forces will be presented. By controlling the density of the seed layer for ZnO nanorod growth, transparent ZnO nanorod arrays were grown on ITO/PES films, and a TF conductive electrode was stacked on the ZnO nanorods. The resulting integrated TF nanodevice (having transparency exceeding 70 %) generated a noticeable current when it was pushed by application of an external load. The output current density was clearly dependent on the force applied. Furthermore, the output current density depended strongly on the morphology and the work function of the top electrode. ZnO nanorod-based nanogenerators with a PdAu, ITO, CNT, and graphene top electrodes gave output current densities of approximately $1-10\;uA/cm^2$ at a load of 0.9 kgf. Our results suggest that our TF nanogenerators are suitable for self-powered TF device applications such as flexible self-powered touch sensors, wearable artificial skins, fully rollable display mobile devices, and battery supplements for wearable cellular phones.

• Journal of Sensor Science and Technology
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• v.32 no.6
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• pp.335-339
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• 2023

Skin-compatible electronics have evolved to achieve both conformality and stretchability for stable contact with deformable biological skin. While existing research has largely concentrated on alternative materials, the potential of Parylene-based thin-film electrodes for stretchable on-skin applications remains relatively untapped. This study proposes an engineering strategy to achieve stretchability using the Parylene thin-film electrode. Unlike the conventional Parylene thin-film electrode, we introduce morphological adaptability via controlled microscale slits in the Parylene electrode structure. The slits-containing device enables unprecedented stretchability while maintaining critical electrical insulation properties during mechanical deformation. Finally, the demonstration on human skin shows the mechanical adaptability of these Parylene-based bioelectrodes while their electrical characteristics remain stable during various stretching conditions. Owing to the ultra-thinness of the Parylene coating, the wearable bioelectrode not only achieves stretchability but also conforms to the skin. Our findings broaden the practical use of Parylene thin-film bioelectrodes.

• Journal of Industrial Convergence
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• v.20 no.12
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• pp.79-85
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• 2022

Recently, a smartphone manufactured on a flexible substrate has been released as an electronic device, and research on a stretchable electronic device is in progress. In this paper, a silicon-based stretchable material is made and used as a substrate to implement and evaluate an optical sensor device using oxide semiconductor. To this end, a substrate that stretches well at room temperature was made using a silicone-based solution rubber, and the elongation of 350% of the material was confirmed, and optical properties such as reflectivity, transmittance, and absorbance were measured. Next, since the surface of these materials is hydrophobic, oxygen-based plasma surface treatment was performed to clean the surface and change the surface to hydrophilicity. After depositing an AZO-based oxide film with vacuum equipment, an Ag electrode was formed using a cotton swab or a metal mast to complete the photosensor. The optoelectronic device analyzed the change in current according to the voltage when light was irradiated and when it was not, and the photocurrent caused by light was observed. In addition, the effect of the optical sensor according to the folding was additionally tested using a bending machine. In the future, we plan to intensively study folding (bending) and stretching optical devices by forming stretchable semiconductor materials and electrodes on stretchable substrates.

• Journal of IKEEE
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• v.13 no.4
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• pp.116-124
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• 2009

Recently the CPU performance of modem chipsets or multimedia processors of mobile phone is as high as notebook PC. That is why mobile phone has been emerged as a leading ICON on the convergence of consumer electronics. The various applications of mobile phone such as DMB, digital camera, video telephony and internet full browsing are servicing to consumers. To meet all the demands the image quality has been increasingly important. Mobile phone is a portable device which is widely using in both the indoor and outside environments, so it is needed to be overcome to deteriorate image quality depending on environmental light source. Furthermore touch window is popular on the mobile display panel and it makes contrast loss because of low transmittance of ITO film. This paper presents the image enhancement algorithm to be embedded on image enhancement SoC. In contrast enhancement, we propose Clipped histogram stretching method to make it adaptive with the input images, while S-shape curve and gain/offset method for the static application And CIELCh color space is used to sunlight readability enhancement by controlling the lightness and chroma components which is depended on the sensing value of light sensor. Finally the performance of proposed algorithm is evaluated by using histogram, RGB pixel distribution, entropy and dynamic range of resultant images. We expect that the proposed algorithm is suitable for image enhancement of embedded SoC system which is applicable for the small-sized mobile display.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.1-10
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• 2014

PURPOSE: The purpose of this study was to investigate the effects of flexible derotator of femur orthosis (FDO) during treadmill gait training on the quadriceps-angle (Q-angle), lateral pelvic tilt, gait speed, and number of steps in children with cerebral palsy. METHODS: Seven children with cerebral palsy who had rotational deformity of the lower extremities participated in this study. We used single group repeated measure design. The procedure consisted of baseline phase, intervention phase, and post-intervention phase. The baseline phase consisted of stretching and strengthening exercise and treadmill gait training without FDO. The treatment phase not only included the same procedures as those for baseline, but also included FDO during treadmill gait training. Postural alignment of the lower extremities was assessed with the Q-angle, and lateral pelvic tilt using the Dartfish software program. A 10-m walk test was used to evaluate gait speed and number of steps. RESULTS: For postural alignment, there was significant differences after the application of FDO (p<.05). For gait ability, there was significant differences in all phases (p<.01). CONCLUSION: These finding suggest that the application of FDO during treadmill gait training had a positive effect on the improvement of postural alignment and gait ability in children with cerebral palsy having rotational deformity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.11
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• pp.897-905
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• 2008

Selective catalytic reduction(SCR) is known as one of promising methods for reducing $NO_x$ emissions in diesel exhaust gases. $NO_x$ emissions react with ammonia in the catalyst surface of SCR system at working temperature of catalyst. In this study, to raise the reacting temperature when the exhaust gas temperature is too low, a heater is located at the bottom of SCR reactor. At an ambient temperature, ammonia is radially injected perpendicular to the exhaust gas flow at inlet pipe and uniformly mixed in the mixing area after being impinged against the wall. To predict the turbulent model inside the mixing area of SCR system, the standard ${\kappa}\;-\;{\varepsilon}$ model is applied. This work investigates numerically the effects of induced heat on the gaseous flow. The results show that the Taylor-$G{\ddot{o}}rtler$ type vortex is generated after the gaseous flow impinges the wall in which these vortices influence the temperature distribution. The addition of heat disturbs the flow structure in bottom area and then stretching flow occurs. Vorticity strand is also formed when heat is continuously increased. Constriction process takes place, however, when a further heat input over a critical temperature is increased and finally forms shed vortex which is disconnected from the vorticity strand. The strong vortex restricts the heat transport in the gaseous flow.

• Clinics in Shoulder and Elbow
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• v.1 no.2
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• pp.242-249
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• 1998

Stiffness of the elbow joint is relatively common after trauma, ectopic ossification, bum, postoperative scar, and etc. Mild flexion deformity can be reduced by use of active or passive motion exercise, dynamic sling, hinged distractor device, or turnbuckle orthosis. But these methods have disadvantages of difficulty in gaining acceptable range of motion only with stretching exercise, re-contracture after conservative managements and poor results that flexion contracture remained. The common described operative exposures for treatment of the stiff elbow are anterior, lateral, posterior, and medial approach. Through Anterior, lateral and medial approach each has not access to all compartments of the elbow. But, posterior approach has benefits that access to posterior, medial and lateral aspects of the elbow and as needed, fenestration to the olecranon fossa that produces a communication between the anterior and posterior compartments of the elbow are possible. From June 1991 through April 1997, 11 patients who had posttraumatic stiff elbow, were treated with debridement arthroplasty through the posterior approach. The purpose of this study are to introduce technique of the debridement arthroplasty and to evaluate final outcomes. With regarding to preoperative pain degree, mild degree matches to 3 cases, moderate to 3 cases, and severe to 2 cases. In preoperative motion, flexion was average 85° and extension was 30°. Postoperatively nine patients had got the complete relief of pain and two patients continued to have mild pain intermittentely. Postoperative flexion improved to 127° and extension to 2°, so that elbow flexion had improved by an average of 42° and elbow extension by 28°. On the objective scale all patients had good or excellent results and they all felt that they were improved by operation. Debridement arthroplasty is one of excellent procedures for the intractable stiff elbow if it is not unstable or it has not incongrous. But it need a meticulous operative technique and a well-programmed rehabilitation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5945-5949
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• 2014

The rural population is aging and farmers need to aim for mass production. This study examined the work efficiency of clamping and protecting crops. Strong winds are a risk for damage, but there are no reports of studies of the geometric design problem for vegetation. The accuracy of the simulation to obtain a load applied to the actual support and index was examined. The model was selected according to its strength based on the reliability of the simulation. Also acts in force of 0.1N to 0.6N, which can withstand the force of 1.29N with the results of this thesis research. The fixed clamp fixing for agricultural crops designed as a support was examined. These results are expected to help shorten working hours, and improve the growth of crops and disaster prevention.

• Journal of Interdisciplinary Genomics
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• v.1 no.2
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• pp.19-22
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• 2019

CATCH 22 syndrome is rare genetic disease that has various manifestations. Cervical vertebral anomaly, such as Klippel-Feil anomaly, is frequently observed in the patients with CATCH22 syndrome. We present the case of an 11-year-old female patient with CATCH22 syndrome and Klippel-Feil anomaly who had been treated torticollis using the customized soft neck collar. During the patient's first visit to our clinic, she presented with low ear set, skull deformity, intellectual disability, and tilting of the head to the left by approximately 25 degrees. Imaging studies revealed multisegmental fusion and C3 hemivertebrae of the cervical spine and left thoracic scoliosis at T4 with 50 degrees of Cobb's angle. We instructed passive stretching and applied the customized soft neck collar we invented. The ipsilateral aspect of the neck collar is designed to provide vertical support between the clavicle and mandibular angle and is adjustable in height. The Velcro was attached to the neck collar at the point of contact with the ipsilesional mandibular angle, which provides negative sensory feedback, inducing her to tilt neck to the contralesional side. We applied the neck collar for 2 hours a day. After 1 year of treatment, her neck inclination angle improved from 25 to 10 degrees. Providing negative sensory feedback using the customized soft neck collar can be one of the treatment options of postural management in patients with torticollis in cases of CATCH 22 syndrome combined with Klippel-Feil anomaly.

• PNF and Movement
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• v.16 no.1
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• pp.43-50
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• 2018

Purpose: This study examined the effects of a shoulder-strengthening exercise on muscle strength of shoulder flexors and extensors of caregivers. Methods: The study consisted of 19 caregivers (2 males and 17 females) employed by Medical Center B. All the participants took part in an 8-week shoulder muscle strengthening exercise, based on previous studies. In the first week, the subjects took part in a stretching exercise enhance the range of motion. In the second week, they participated in an exercise aimed at improving shoulder blade stability. From the third to seventh weeks, a resistance exercise of different intensities was applied in a phased manner. Finally, in the eight week, the subjects took part in plyometric exercise. Peak torque, average power, and total work of shoulder flexors and extensors in both sides were measured before and after the exercise at an angular speed of 120deg/sec using an isokinetic device. Wilcoxon's singed-ranks test was conducted to analyze differences in muscle strength before and after the intervention. Results: After the exercise, there was a significant improvement in peak torque and average power of flexors of the right arm. After the exercise, peak torque, total work, and average power showed a significant improvement in the flexors of the left arm (p<0.05). However, there was no statistically significant difference in extensor muscle strength in either arm after the exercise. Conclusion: Shoulder flexors of caregivers are utilized frequently in the workplace. Implementation of extensor-strengthening exercises, in addition to flexor-strengthening exercises, can contribute to reducing the incidence rate of shoulder injuries among caregivers.