• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.4
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• pp.265-277
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• 2014

Purpose: The purpose of this study was to investigate the differences of displacement pattern depending on type of sliding jig and application method during maxillary molar distalization with temporary anchorage devices (TADs). Materials and Methods: Maxilla with normal tooth size and arch shape was selected to create a 3-dimensional finite element model, which included the bracket, orthodontic main archwire, removable sliding jig (R-jig). The orthodontic mini-implant anchorage was set 8 mm superiorly from main archwire, buccally between the second premolar and first molar. The base experimental design was Condition 1, which was composed $0.019{\times}0.025$ inch stainless steel (SS) of wire size of R-jig, 200 gm force, un-tied state. And the other designs varied to wire size of R-jig, magnitude of force. The results are as follows. Results: As the wire size of R-jig was increased, the deformation of R-jig was decreased. However, the displacement of second molar wasn't different each other. As the force to second molar was increased, the more displacement of second molar was observed, and the more distal tipping movement, vetical displacement was observed. Conclusion: R-jig can get distal teeth movement in orthodontic treatment without side effects.

• Progress in Medical Physics
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• v.15 no.4
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• pp.192-196
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• 2004

The activity of Ir-192 sources for high dose rate (HDR) Brachytherapy in Korea were measured by using the well-type chamber and using the calibration Jig with the Farmer-type ionization chamber to compare the manufacturer certificated source strength which is supplied with each new Ir-192 source. The activity of two different source models used in six hospitals were measured. The range of measured activities to the manufacturer's suggested ones was -2.40% to +3.31% for the calibration Jig and -3.12% to 0.00% for the well-type chamber system. The source strength values given by the manufacturer for the 6 sources were within ${\pm}5%$ for the two different measuring equipment. Our results demonstrate that well-type chamber as wall as Farmer-type chamber system are appropriate system for the routine source calibration procedures in HDR brachytherapy. Whenever a new source is installed to use in clinics, a source calibration should be carried out.

• The korean journal of orthodontics
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• v.1 no.1
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• pp.9-14
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• 1970

저자는 현재 Light-Wire Technique에서 많이 사용되는 0.016" 및 0.018"의 원형 녹색 "Elgiloy" 교정용 탄선의 Residual Stress가 열처리에 의하여 제거되는 양을 Testing Jig를 사용하여 측정하였다. 그 결과는 다음과 같다. 1. 0.016" 및 0.018"의 원형 녹색 "Elgiloy" 교정용 탄선은 열처리 시 온도의 증가에 따라 제거되는 Residual stress의 양도 증가한다. 2. 동일 온도조건에서 시간조건의 변화에 따른 Residual Stress의 제거치는 차이는 있었으나 현저하다고 인정할 수 없다. 3. 통상적 열처리 방법에 의하면 제거된 Residual Stress의 양은 0.016"인 경우 $26.95\%\~38.54\%$, 0.018"인 경우 $27.06\%\~41.05\%$이다. 4. $950^{\circ}F$에서 열처리했을 시 제거된 Residual Stress의 양은 0.016"인 경우 $38.54\%\~43.16\%$, 0.018"인 경우 $41.05\%\~44.56\%$이다.

• The korean journal of orthodontics
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• v.24 no.1 s.44
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• pp.87-94
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• 1994

The purpose of this study was to evaluate the torque effect of othodontic wires. Ten types of orthodontic wires (five types of materials, two types of cross-sectional dimensions) were selected. Each group of ire type was constituted with five specimens. These specimens were tested on the universal testing machine(Instron) with specially-designed jig. The torque-twist curve of each wire was obtained and the results were analyzed statistically. The results were as follows. 1. 0.017'$\times$ 0.025' wire showed more torque effect than 0.016'$\times$ 0.022' wire at the same twist. 2.Torque effect was the greatest in stainless steel and the least in Nitinol. 3.The maximum amount of torque was the greatest in heat-treated Blue Elgiloy and the least in Nitinol.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.299-303
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• 1989

Authors have developed highly reproducible calibration method for the Micro-Selectron HDR Ir-192 system (Nucletron, Motherland). The new jig has a 10cm radius circular hole in the $30cm{\times}30cm{\times}0.2cm$ acrylic plate, and 5F flexible bronchial tubes are attached around the hole. The source moves along the circle in the tubes and the ionization chamber is placed verticaly at the center of the circular hole (center of the jig). Dose distribution near the center was derived theoretically, and measured with the film dosimetry system. Theoretical calculation and measurement show the error margin below $0.1\%$ for 1mm or 2mm position deviation. We have measured at 12 and 24 points of circle with 1, 6, 11 and 21 second dwell time of source in order to calculate the activity of the source. Measurements have been repeated daily for 50 days. The accuracy and the reproducibility are below $1\%$ error margin. The half life of the source from our measurement is estimated $73.4\pm0.4$ days.

• Progress in Medical Physics
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• v.19 no.4
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• pp.305-312
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• 2008

The aim of this study is to introduce the accuracy of Ir-192 source's apparent activity using the well-type chamber and the Farmer-type ionization chamber in the high dose rate brachytherapy. We measured the apparent activity of Ir-192 that each medical center in the country has and the apparent activity of calibration certificate provided by manufacturer is compared with that by our experimental measurement. The number of sources used for the activity comparison was 5. The accuracy of the measured activity was in the range of -2.8% to -1.0% and -2.1% to 0.2% for the Farmer-type chamber system (Jig) and for the well-type, respectively. The maximum difference was within 1.0% for comparison with two calibration's tool. Our results demonstrate that well-type chamber as wall as Farmer-type chamber is a appropriate system as the routine source calibration procedures in HDR brachytherapy. Whenever a new source is installed to use in clinics, by periods, a source calibration should be carried out.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.43-48
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• 2010

The heat sink system for a main board in a network server computer is built on printed circuit board by an anchor structure, mounted by eutectic SnPb solder. The solder creeping is caused by a constant high temperature condition in the computer and it eventually makes fatal failures. The FE model is used to calculate the stress and predict the life of soldered anchor in the computer. In the model, Anand constitutive equation is employed to simulate creep characteristics of solder. The creep test is conducted to verify and calibrate the solder model. A special jig is designed to mitigate the flexure of printed circuit board and to get the creep deformation of solder only in the test. Test results are compared with analysis and calibration is conducted on Anand model's constants. Precise life prediction of soldered anchor in creep condition can be performed by this model.