• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.829-844
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• 2020

A vacuum metering device for garlic seeds was developed, and its metering performance was tested according to the design factors. Three design factors were as follows: suction surface diameter (Edge), suction surface curvature (Type), and guide height (Guide). The suction surface curvature represents the distance between the center of the grooved suction plate and the bottom of suction plate. The metering rate and multiple metering rate were analyzed as the metering performance of the developed device with two varieties of garlic seeds: Namhae (warm region-adapted garlic) and Uiseong (cold region-adapted garlic). The best metering performance for the Namhae seeds were found with the following conditions: An Edge, Guide and Type of 40, 4, and 35 mm, respectively. In the case of the Uiseong seeds, the best conditions were as follows: An Edge, Guide and Type of 35, 4, and 30 mm, respectively. The guide height was found to be the most influential design factor on the metering performance of the metering rate and multiple rate for both Namhae seeds and Uiseong seeds. Additionally, the interaction between the area of the suction surface and the curvature of the suction surface had some effects on the multiple rate for the Uiseong seeds. It was concluded that the guide height should be 4 mm or higher so that more than 90% of the metering rate could be achieved for the tested garlic seeds with the developed metering device.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.1
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• pp.13-22
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• 2021

Purpose : The purpose of this study was to investigate the effects of a virtual reality-based occupational therapy program on the physical function and learning ability of intellectually disabled school-aged children. Methods : In this study, 20 intellectually disabled children of school age were randomly and evenly divided into experimental and control groups with children in the experimental group receiving a virtual reality-based occupational therapy intervention. The study adopted a pretest-posttest design. The intervention was conducted for a total of 12 sessions for six weeks, twice a week, and 50 minutes per session. As measurement tools, BOT-2 and grooved pegboard tests were used to compare physical function before and after the intervention program, and K-ABC was used to check changes in learning ability. Results : The occupational therapy program produced a significant improvement in both physical function and learning ability of the experimental group. A significant difference was observed between the experimental and control groups. Conclusion : This study confirmed the value and usefulness of virtual reality-based occupational therapy as a tool for enhancing the physical function and learning ability of intellectually disabled school-aged children. Based on the results, a variety of future studies are encouraged that would further test the effects of the occupational therapy program used here.

• Advances in concrete construction
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• v.15 no.6
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• pp.431-444
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• 2023

This study investigated the use of latex-modified sand concrete reinforced with sisal fibers (LMSC) as a repair material. Notably, no prior research has explored the application of LMSC for this purpose. This paper examines the interface bond strength and the type of failure between LMSC as a repair material and the normal concrete (NC) substrate utilising four different surfaces: without surface preparation as a reference (SR), hand hammer (HA), sandblasted (SB), and grooved (GR). The bond strength was measured by bi-surface shear, splitting tensile, and pull-off strength tests at 7, 28, and 90 days. Scanning electron microscopy analysis was also performed to study the microstructure of the interface between the normal concrete substrate and the latex-modified sand concrete reinforced with sisal fibers. The results of this study indicate that LMSC has bonding strength with NC, especially for HR and SB surfaces with high roughness. Therefore, substrate NC surface roughness is essential in increasing the bonding strength and adhesion. Eventually, The LMSC has the potential to repair and rehabilitate concrete structures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2245-2251
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• 2013

In this paper, a design of a compact series-fed dipole pair(SDP) antenna with end-loaded rectangular patches is presented. In order to reduce the lateral size of a conventional SDP antenna, rectangular patches are end-loaded to the two dipole elements of the SDP antenna and a grooved ground plane is used by adding a patch at both ends of the ground plane. The effects of varying the length and width of the rectangular patches on the antenna performance such as input reflection coefficient are investigated. An optimized compact SDP antenna covering a frequency band ranging from 1.7 GHz to 2.7 GHz is designed and fabricated on an FR4 substrate. The total width of the fabricated prototype of the proposed antenna is reduced by approximately 14.3% compared to the conventional SDP antenna. Experimental results show that the antenna presents a 48.7% bandwidth in the range of 1.68-2.76 GHz and a stable gain of 5.6-6.0 dBi with minimal degradation. Moreover, a front-to-back ratio is improved by about 0.7 to 7.4 dB.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.96-96
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• 2012

복합분자펌프는 기존의 터보분자펌프 turbine blade에 spiral grooved를 추가하여 초고진공(10-8Pa)에서 저진공(330Pa)까지 넓은 압력범위에서 사용할 수 있고 이 펌프를 사용함으로서 완전 oil free한 진공시스템을 만들 수 있는 특징을 가지고 있다. 특히, 회전체를 비접촉으로 지지하는 자기베어링 방식을 적용함으로써, 진동은 극히 작고 베어링수명은 길면서 중저진공에 대한 배기속도가 크고 임의의 방향으로 접속이 가능하여 반도체 및 디스플레이 제조 공정과 같은 첨단산업의 다양한 분야에 쉽게 적용되고 있으며, 그 적용 분야와 시장은 계속 성장하고 있다. 고 진공과 배기 속도의 달성을 위해서, 고속으로 이동하는 격면과 기체분자를 충돌시켜, 기체 분자를 원하는 방향으로 유도하는 작동원리를 가지고 있다. 특히 공기분자의 밀도가 매우 낮은 희박가스 상태에서 고속 회전하는 blade로 공기분자를 쳐내면서 작동됨으로써 날개의 상하 압력차에 의한 공기력보다도 날개의 고속회전이 매우 중요시되고 압력으로는 10-1 Pa 이하의 분자영역에서 그 성능을 최고로 발휘할 수 있다. 이러한 복합 펌프의 주요 장점은 다음과 같다. 1. 10-8 Pa (10-10 torr) ~ 10 Pa (1 torr) 까지 넓은 영역에서 배기가 가능하다. 2. 탄화수계의 대하여 높은 압축특성을 가지고 있고, 윤활유를 사용하지 않으므로 얻을 수 있는 진공상태가 고청정하다(oil free). 3. 정밀 5축제어 자기베어링으로 완전히 부상하여 회전함으로서 마모가 없고 진동이 최소화하였을 뿐 만 아니라, 또한 운전음도 거의 없다. 4. 설치조건에 제한이 없고 고장이 거의 없다. 특히 복합분자펌프는 탄화수소화합물이 없는 진공을 생성시키면서 구성요소가 간단한 반면 폭넓은 진공대역을 충족하기 때문에 산업계와 연구계의 주요 첨단 분야에서 광범위하게 사용되고 있으며, 최근 반도체 및 디스플레이, 바이오엔지니어링 등의 발전으로 적용분야가 넓어지고 있다.

• Journal of Fisheries and Marine Sciences Education
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• v.13 no.1
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• pp.87-98
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• 2001

1. The bottom mean size of the research area had been showed 86.8% in, 13.2% in mud artificial sector, but and 82.4% in mud at comparative sector. 2. The water temperature had been showed $11.2{\sim}12^{\circ}C$ in surface, $10.9^{\circ}C$ in mid layer, $10.6{\sim}10.8^{\circ}C$ in lower layer. also, The salinity had been showed $31.85{\sim}31.95_{psu}$ in surface, $31.82{\sim}31.97_{psu}$ in mid layer, $31.85{\sim}31.97_{psu}$ at lower layer. The transparency was showed 3.6~5.6m. 3. The conservation condition of reefs was partially grooved and buried the lower part of reefs established '95~'96years but was good condition generaly. 4. The attached fauna has been appeared fisheres botanical specise 6, fisheries animate species 5. 5. The lure of fisheres has been appeared 17 species in reefs sector, 10 species in comparative sector(natural fishing ground). 6. The catchs of C.P.U.E by fishery was catched 2.2~3.3 times in reefs sector than the natural fishing ground. but the individuals was much catched in traps. The jumbo type reefs gill netter were much catched in square artificial reefs. The weight of fishery was much captured in jumbo type reefs.

• Transactions of Materials Processing
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• v.14 no.5 s.77
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• pp.432-438
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• 2005

Among the most of manufacturing process, plastic deformation method offers a significant advantage in productivity and enable mass production with controlled quality and low cost. From the point of view, micro forming is a well suited technology in manufacturing very small metallic parts, in particular for mass production, as they are required in many industrial products. Meanwhile, Al 5083 superplastic alloy with very small grains has a great advantage in achieving micro deformation under low stress due to its relatively low strength at a specific high temperature range. This paper describes the micro formability of Al 5083 superplastic alloy and its application to die forging of micro patterns. Micro formability tests of Al 5083 superplastic alloy were carried out with the specially designed micro forging system by using V-grooved micro dies and pyramidal dies made of (100) silicon. With these dies, micro forging was conducted by varying the applied load, material temperature and forging time The micro formability of Al 5083 superplastic alloy was evaluated by comparing $R_f$ value, where $R_f\;=\;A_f/A_v$ ($A_v$ : cross-sectional area of the flowed metal, $A_v$ : cross sectional area of V-groove). The micro formability of 3 dimensional Patterns was also evaluated using Pyramidal type micro dies.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.3
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• pp.240-245
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• 2013

Each pixel of InfraRed(IR) sensor differently responds to IR light as time elapses or the sensor on/off operation is repeated. As a result, the quality of IR sensor image is deteriorated, and therefore NUC(Non-uniformity Correction) is periodically needed for IR sensor. In this paper, in order to perform NUC in the Satellite, on-board V-grooved blackbody is designed with a baffle so that the emissivity of black body is to be higher than 0.995 as well as the temperature deviation is less than $1^{\circ}C$ in the range of the infrared wave length from 3.3 to $5.2{\mu}m$. To check its performance, the emissivity and the surface temperature of the blackbody by TRT(Transfer Reference Thermometer) and IR Micrometer scanner are measured, respectively. From the results, black body design is verified and the uncertainty of NUC is estimated through the measurement results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.918-921
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• 2002

Some investigators who have tried to achieve the highly smooth surface finish using electrochemical processes have reported that high current density produced lustrous surfaces while the opposite conditions produced a passive layer and had a tendency to produce a black surface. However, processing at a low current density may produce a non-lustrous surface but the improvement of dimensional accuracy of the surface is significant. The surface with pulse process was a bit more lustrous than with continuous current but the black passive layer still could be found at grooved surface. There are two ways to achieve highly smooth surface finish. One is brushing it with a brush the other is electrochemical machining (ECM) with high current. The former method is the most common polishing practice, but not only may the surface obtained differ from operator to operator, but precision smooth surface on micro grooves are difficult to obtain. The latter one recently has been used to produce a highly smooth surface after EDM process. However, the material removal rate in ECM with high current is relatively high. Hence the original shape of the micro grooves, which was formed by electrochemical micro-machining (EMM) process, may be destroyed. In this study, an electrochemical polishing process using pulse current is adopted as a possible alternative process when micro grooves formed by EMM process should be polished. Mirror-like micro grooves with lustrous and smooth surface can be produced electrochemically with pulse current because the voltage and current used can be lower than the case of continuous current. This study will discuss the accurate control of physical and electrical conditions so as to achieve mirror-like micro grooves with lustrous and smooth surface without destroying the original shape of micro grooves.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.176-183
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• 2002

Plasma Display Panel(PDP) is a type of flat panel display utilizing the light emission produced by gas discharge. Barrier Ribs of PDP separating each sub-pixel prevents optical and electrical crosstalks from adjacent sub-pixels. The mold for forming the barrier ribs has been newly researched to overcome the disadvantages of conventional manufacturing processes such as screen printing, sand-blasting and photosensitive glass methods. The mold for PDP barrier ribs have stripes of micro grooves transferring glass-material wall. In this paper , Stripes of grooves of which width 48$\mu$m, depth 124$\mu$m , pitch 274$\mu$m was acquired by machining of single crystal silicon with dicing saw blade. Maximum roughness of the bottom of the grooves was 59.6 nm Ra in grooving Si. Barrier ribs were farmed with silicone rubber mold, which is transferred from grooved Si forming hard mold. Silicone rubber mold has the elasticity, which enable to accommodate the waviness of lower glass plate of PDP. The methods assisted by the microwave and UV was adopted for reducing the forming time of glass paste.