• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.1-6
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• 2015

Generating output characteristics of a ${\pi}$-type piezoelectric harvester depending on size of the ceramic and the elastic body were studied. The ${\pi}$-type piezoelectric harvester consists of a rectangular piezoelectric ceramic and a ${\pi}$ shaped elastic body. If the tensions is applied at both ends of an elastic body legs, the piezoelectric effect occurs at the ceramics through the form change of the elastic body. The structure of this ${\pi}$-type harvester can be used in a various area than an existing type generator, because it prevent from direct pressure to the ceramic. Generating characteristics of the harvester were analyzed by using finite element method program. The piezoelectric harvester was fabricated on the basis of analyzed results and attached on a frequency controllable vibrator to measure the output characteristics. And generating characteristics were defined by comparing analysis results and experimental results. The highest output voltage was obtained when the ceramic length, thickness were 20 mm, 0.5 mm in the analysis result. And experiment was performed by analysis results at low frequency region, output voltage was generated about 6 V.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.5
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• pp.650-661
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• 2005

Statement of problem: It could be hypothesised that attachments, which provide more retention against vortical and horizontal dislodgement, will be associated with more favorable parameters of oral function. Purpose: This study was to provide data of initial retentive force and retention loss of different bar attachment systems recommended for use with maxillary implant overdentures. Material and method: 4 implants were placed in the anterior region of edentulous maxilla, five different systems of bar attachment were fabricated as follows: cantilevered Hader bar using clips (Type 1), Hader bar using clips without cantilever (Type 2), Hader bar using clip and ERA attachment orange male (Type 3), Hader bar using clip and ERA attachment white male (Type 4), and Bar using magnets (Type 5). Each samples were placed in the universal testing machine for determination of retentive forces(at initial and after every 200 cycles up to 1,000 cycles). Results and Conclusion 1. Attachment type 1 showed the biggest initial retentive force followed by type 3, type 2, type 4, and lastly type 5(P<0.001). 2. After 1,000 cycles of repeated removals of attachments, significant loss of retentive forces was taken place except for attachment type 5. 3. After 1,000 cycles of repeated removals, the loss of retentive force between type 1 and type 2, which used Hader bar and clip attachments. was greater in type 1 that had wider clip formation. And between type 3 and type 4, which used ERA attachments, the loss of retentive force was greater in type 4 that had white male attached (P<0.001). 4. After 1.000 cycles of repeated removals, attachment type 3 showed the biggest retentive force followed by type 2, type 4, type 1 and lastly type. 5. There was no significant difference between attachment type 3 and 4, and type 4 and 1(P<0.001).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.242-246
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• 2017

In this study, it was investigated about optical simulation in high brightness and high uniformity general lighting using glass light guide plate. And we adopt edge-light emission type light plate. Edge-light type lighting has been used LCD application, especially note PC or smart phone backlight unit. Because it had the good properties such as slim shape and light weight. We thought this type was suitable for general lighting application such as wall attached type or ceiling mount type. But many of edge-light type lighting had problems. It called slanted output light rays. That was main key parameter how could control the direction of output light rays. We investigated the solution of this problems, using ray tracing method, we recognized the major fact of the solution relied on the geometric structure of diffusing dot shape. We set the conditions of aspect ratio in diffusing dot shape such as 0.5 to 1. And, at first, we designed diffusing dots shape based on the results of optical simulation and made specimen. as above condition, and acquired good result in confirming dots shape such as the value of the output rays's peak angle was around 75 degrees. And good light distribution characteristics were measured by slated spectro-radiometer. It was shown that the effective ways of designing light distribution characteristics using optical simulation such as ray tracing linear method for making general lighting using glass light guide plate.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.243-246
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• 2006

Most of the guided weapons have been kept and transferred at the launching tube and fired in case of necessity in these day. Launching tube is a kind of case to protect the guided weapons from external environments and conducted as a guide when they are fired. When we attached the guided weapons to launching tube we usually has used explosive bolt. Explosive bolts have been used explosives when they had to be separated. But when they are separated there are some bad effects; a flame, fragments and pyre-shock. Because of these bad effects there are many restriction to use bolt as joining devices to precision guided weapons. To solve these problems we invented ball type bolt. Unlike explosive bolt, ball type bolt is separated without a flame, fragments and pyre-shock. And it also has a good mechanical properties as much as those of explosive bolt.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.179-182
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• 2008

Most of the guided weapons have been kept and transferred at the launching tube and fired in case of necessity in these day. Launching tube is a kind of case to protect the guided weapons from external environments and conducted as a guide when they are fired. When we attached the guided weapons to launching tube we usually has used explosive bolt. Explosive bolts have been used explosives when they had to be separated. But when they are separated there are some bad effects; a flame, fragments and pyro-shock. Because of these bad effects there are many restriction to use bolt as joining devices to precision guided weapons. To solve these problems we invented ball type bolt. Unlike explosive bolt, ball type bolt is separated without a flame, fragments and pyro-shock. And it also has a good mechanical properties as much as those of explosive bolt.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.4
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• pp.87-97
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• 2020

The livestock infections had been happened seasonally, but they have gradually changed to be irrelevant to seasons and have an aspect to rapidly spread after outbreak. Especially in Korea, proactive disinfection measures are very important because the livestock farms are located densely so high as to accelerate the spread of disease between farms. livestock disease outbreaks like HPAI and FMD occurred with high probability due to vehicles visiting the farms, this study is to evaluate the efficiency of livestock vehicle disinfection systems by investigating the disinfectant coverage according to the type of vehicle disinfection system and the type of vehicle quantitatively. In field experiments, water-sensitive papers (WSPs) were attached to 21 locations on the surface of four vehicles (sedan, SUV, truck, and feed transport), respectively, and exposed to disinfectants while the vehicle was sprayed in two vehicle disinfection systems (tunnel type and simplified type). The WSPs were scanned and image-processed to calculate the disinfectant coverage. The results showed that the tunnel-type vehicle disinfection system had a better disinfection performance with an average coverage of 90.27% for all vehicles compared to 32.62% of the simplified type system. The problem of the simplified system was a wide coefficient of variation (1.05-1.31) of the disinfectant coverage between 21 locations indicating a need for further improvement of nozzle location and arrangement.

• Journal of the Korean Society of Costume
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• v.59 no.8
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• pp.49-65
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• 2009

As basic materials in this research, 874 pieces of engraving that recorded the garment produced by diverse authors in the 17-18th century were collected among the collections of male and female garment in the engraving kept by National Library of France and 216 pieces of engraving were classified among them to observe justaucorps as stated in the materials. Since type of justaucorps in the 18th century can be classified by difference in shape and change through the above engraving materials in large quantity and the shape and composition can be compared and analyzed with other materials such as picture, stored garment, written materials without difficulty, the chronology can be composed by single type of justaucorps. Intending to understand the change in composition caused by type classification and pattern making as per analysis of type property of justaucorps, the men's upper garment in France in the 18th century. Checking change in design per from and materials, justaucorps of 1680-1700s was in silhouette where waist in the length above knee was adhered and slightly spread to lower part. In the type of 1710-1750s, waist adhered remarkably and many pleats were made under waist to produce volume of form that spread to lower part like skirt. In the type of 1760-1780s, straight silhouette was attached to whole body and end of front adjustment in slant line turns to rear part. The developmental aspect of construction can be checked by making pattern. Changing the cutting line of body plate to smoothly connect section and to try to adhere to the body, the development of simpler and delicate pattern production technique was confirmed.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.3
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• pp.41-49
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• 1999

A feasibility study is performed for practical application of a Ventilating Water-Jet(VWJ) propulsor which attracts new attention as a candidate propulsor for super-high speed vessels. Super-cavitating foil sections are adopted for the rotor blades since the rotor is operating at ventilating condition. Wedge type and cavitator type foil sections are used for the design of rotor blades. Other geometric characteristics of rotors are selected from the Kaplan type ducted propeller rotors. The test section of KRISO cavitation tunnel is modified to perform open-water tests of the VWJ propulsors. The tests are performed both at fully-submerged and free-jet conditions. Ventilation occurred at the free-jet condition by sucking the air in the downstream side of the rotor, which easily develops as super-cavitation when the rotor operates at lower advance coefficients. Spoilers are attached at the trailing end of the pressure side of the blade section, in order to increase the lift force.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.6
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• pp.470-475
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• 2017

Since the intake air of gas turbine engine of marine purpose contains water particles, inertial separator for separating the air and water particles are provided. Saw type and wave type separator are now used to separate inflow water particle from the gas. In this paper, the design parameters of saw type separator are studied by numerical simulations. Using the commercial CFD program, Star-CCM+, Lagrangian-Eulerian method was used to perform the analysis of two phase flow of the mist in the air. This method solves Reynolds-Averaged Navier-Stokes equations in Eulerian framework for the continuous phase, while solves equation of motion for individual particles in Lagrangian framework. Lagrangian multiphase method was applied to monitor the particles of different sizes and shapes and to verify collision between particles by chasing particles. Water particles were injected through injectors located at the inlet of the separator and escape mode was used which assumes that the particles attached on the surface of inertial separator were removed from the simulation, effectively escaping the solution domain. Through the numerical computations with the inlet condition of constant water particle size in the wetness fraction of 85%, efficiency of eliminating the water particle and the pressure drop between the inlet and outlet were examined.

• Fashion, Industry and Education
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• v.14 no.2
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• pp.1-10
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• 2016

In the present study, the materials, sizes, and designs of blind eye patch products of skin-adhesive type and glass-attachment type currently available in the market will be analyzed and ergonomically appropriate blind eye patches will be developed. Although these skin-adhesive type eye patches were easy to use, they had shortcomings such as skin troubles due to the adhesive used on the weak and sensitive skin of children and the fact that eyebrows are pulled out and the skin is irritated when the eye patches are detached after being attached. The non-adhesive type eye patches were blind patches to be worn by putting into glasses. These products were made using diverse materials such as neoprene, non-woven fabrics, and felt and showed differences in tactile impressions and irritation to the skin depending on material characteristics. In addition, most products were efficient in blocking light with three-dimensional oval designs comprising darts. In the present study, blind eye patches were designed to reduce skin troubles by using sweat-absorbing and quick-drying functional materials with soft tactile impressions. In addition, to increase the effect to block light and the degree of tight contact with the skin when the blind eye patches are worn compared to existing eye patch designs, the sides of the wings of the blind eye patches were widened, glass frame fixing plates were added, and the darts were made to be curved thereby making an ergonomic design reflecting the shape of the face. The non-adhesive type blind eye patches developed in the present study are considered to enhance the wearing sensation with the use of the material without skin irritation but with cushioning feelings and the ergonomic design reflecting the contour of the face.