• Journal of electromagnetic engineering and science
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• v.7 no.1
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• pp.47-52
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• 2007

We investigated the effects of substrate, metal-line, and surface material on the performance of radio frequency identification(RFID) tag antenna using a tag antenna with a meander line radiator and T-matching network. The results showed that readability of the tag antenna with a thin high-loss substrate could be increased so that it was similar to that of a low-loss substrate if the substrate was very thin. The readability of the tag antenna decreased significantly when the metal line was thinner than the skin depth. The readability of the tag also decreased drastically when the tag was attached to high-permittivity high-loss target objects.

• Research in Community and Public Health Nursing
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• v.14 no.3
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• pp.479-487
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• 2003

Purpose: This study was conducted to investigate the progression of Cobb's angle of middle school students according to the Risser grade changes during a one-year follow up period, and to identify the prevalence rate and related factors regarding scoliosis. Method: A total of 2,124 middle school students were preliminarily screened by the Adam's forward bending test. Among them, 21 adolescents diagnosed with scoliosis (above 5Cobb's angle) by X-Raying were the subjects and followed up for checking Cobb's angle and the Risser grade for one year. Results: The overall prevalence of scoliosis in middle school students was 2.13% and the prevalence in girls was higher than in boys. The Cobb's angle was significantly high in seniors and girls. The cases in low angle and low Risser grade demonstrated significant changes in progressive Cobb's angle compared to the cases in high angle and high Risser grade after one-year. But gender and pattern of curvature were not significantly different from the changes scoliosis angle after one-year. Conclusion: Based on these study results, juniors in low Risser grade were inclined to aggravate scoliosis despite the low degree of curvature at the first measurement.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.69-76
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• 1999

The mandibular buccal frenum is defined as a fold of mucous membrane at the posterior labial vestibule and attaches the lips and the cheeks to the alveolar mucosa, gingiva, and underlying periosteum. The buccal frenum becomes a problem when its attachment is too close to the marginal gingiva. It may then pull on healthy gingiva, encourage plaque formation and interfere with tooth brushing. Especially, heavy buccal frenum mucogingivally results in insufficent attached gingiva, inadequate vestibular depth and high frenum attachment and also difficulty in eruption of mandibular premolar. Frenotomy, frenectomy and mucogingival surgery are used in treating heavy buccal frenum. Frenotomy with autogenous free gingival graft has been used popularly because of its stable result. But, it is difficult in younger children because of inadequate donor site, difficulty in making recipient site and behavior management. Frenotomy with apically positioned flap is considered as more efficient way for a very young child with heavy buccal frenum. Additionally, modified deep sedation with $N_2O-O_2$ can be used as an adjunct for the effective treatment outcome. Decrease in muscle pull, adequate width of attached gingiva and increased vestibular depth can be expected from this treatment approach.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.54-69
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• 1996

The purpose of this vitro study was to evaluate attachment and proliferation of human pulpal cells to the attachment glycoprotein-coated and non-coated culture dishes. Well known adhesive glycoproteins were used, such as type I collagen, type IV collagen, fibronectin, laminin, and vitronection. Each adhesive glycoproteins applied onto the culture dishes. In this study, the protein coated and non-coated dishes were classified as each groups. Human pulpal cells onto each culture dishes. After 90 minute, 4 hour and 24 hour incubation attached cells in each group were counted with hematocytometer for evaluation of the attachemnt of human pulpal cells. The configurations of attached human pulpal cells were done by SEM observation. The results as follows : 1. After 90 minute incubation the score of attachment of human pulpal cells was best in laminin-coated group among groups. Then fibronectin, type IV collagen group were better, and all proteins were higher than control. 2. After 4 hour incubation the numbers of attachment of human pulpal cells were most in fibronectin coated group. 3. After 24 hour incubation all of adhesive glycoproteins showed high and similar attachemtn effect to human pulpal cells. 4. In SEM observation, fibronectin and type IV collagen groups showed well spreaded human pulpal cells, then laminin group was moderately spreaded, and vitronectin group was mildly spreaded as well as control group.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.346-351
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• 1998

Cutting process has been automated due to progress of CNC and CAD/CAM, but polishing process has been only depended on experiential knowledge of expert. Polishing work for a curved surface die demands simple and repetitive operations but requires much time for its high precision. Therefore it is operated in the handiwork by skilled worker. However the workers intend to avoid gradually polishing work because of the poor environments such as dust and noise. In order to reduce the polishing time and solve the problem of shortage of skilled workers, it has been done some research for an automation of polishing. To automate the polishing process, a 2 axes polishing robot which is attached to a 3 axes machining center has been developed by our previous research. This automatic polishing robot is able to keep the polishing tool normal on the curved surface of die. Therefore its performance of polishing is improved because of always keeping the tool normal on the surface. In this paper, the smaller sized polishing robot is developed to improve polishing performance. And the controller for 2 axes polishing robot is developed. The controller is composed of TMS320C31 with high speed which is 40-ns instruction cycle time, RAM memory with 64K words, digital input with 64 bits, digital output with 32 bits, and D/A converter with 4 channels, which is 12 bits resolution. To evaluate polishing performance of this developed robot, polishing experiment for shadow mask was carried out.

• Journal of the Korean Institute of Gas
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• v.22 no.1
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• pp.1-8
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• 2018

FCV is installed with a automatic valve attached in an high pressure cylinder to control the hydrogen flow. The supply of hydrogen from the cylinder into the fuel cell stack is controlled via the on/off operation of a solenoid attached to the automatic valve. The solenoid needs to provide the necessary attraction force even at any saturation temperature caused by drive of the vehicle. In this study, the simplified prediction equations for the saturation temperature are suggested. The finite element analysis was performed by steady state technique, according to the boundary condition in order to predict the saturation temperature and attraction force. Finally, the saturation temperature was validated through comparison between the analysis results and measurement results. From the results, the measured saturation temperature $5.9^{\circ}C$ lower with respect to the analysis results. And the error of attraction force ranged from 1.0 to 2.1 N at testing conditions.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.6
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• pp.26-32
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• 2019

Ball end mills used for high-speed and high-precision machining require longer machining time than flat end mills or face cutters, since the tool diameter is limited and the rigidity is reduced by the characteristics of the tool's cutting edge: at the top end of the tool, the cutting speed approaches zero and hardly removes any material. Because there is little material removal at the top end of the ball end mill, the outer cutting edge performs the majority of the work; this irregular cutting force deforms the tool and shortens its life. In this study, we attached an eddy-current sensor to a tool to measure the deformation from the cutting force and we used a tool dynamometer to measure the cutting force. We found that the change in cutting force is dependent on the change in feed rate during square-shaped processing and, as the feed rate is accelerated, the cutting force also increases. Higher cutting forces increase tool deformation.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2702-2706
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• 2013

Silver nanoparticles (AgNPs) with spherical and prism morphologies were formed at room temperature depend on the amino acid attached with phenolic unit. Absorption studies showed 410-420 nm surface plasmon resonance absorption for spherical nanoparticles whereas prism morphology showed three absorption peaks (382, 452 and 523 nm). The formation of spherical and prism morphology was confirmed by scanning and high resolution transmission electron microscopy. Antibacterial studies of both the morphologies did not show any significant differences in the inhibition of bacterial growth.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.32-35
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• 1998

Polypropylene fibers are difficult to dye by conventional dyeing techniques due either to lack of dye receptor sites in their molecular structure to with the dye molecules may become attached, or to difficult of penetration of certain types of dye molecules into the structure$^1$. Although the diffusion coefficient of disperse dyes into polypropylene is quite high, the saturation values are very low.(omitted)

• Journal of Multimedia Information System
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• v.7 no.2
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• pp.165-174
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• 2020

This document outlines a new color image encryption technology development. After splitting the original image into 240-bit blocks and modifying the first block by an initialization vector, an improved Feistel circuit is applied, sponsored by a genetic crossover operator and then strong chaining between the encrypted block and the next clear block is attached to set up the confusion-diffusion and heighten the avalanche effect, which protects the system from any known attack. Simulations carried out on a large database of color images of different sizes and formats prove the robustness of such a system.