• Current Optics and Photonics
• /
• v.5 no.1
• /
• pp.52-58
• /
• 2021

We show that a simple double-slit experimental setup can be used to measure the thickness of a transparent thin film. The phase difference between the light passing through one slit covered with photoresist film and that passing through the other slit without film was estimated using the simple Fraunhofer diffraction formula for a double slit. Our method gave error of a few percent or less for film thicknesses ranging from 0.7 to 1.7 ㎛, demonstrating that a laboratory double-slit experimental setup can be utilized in practical film-thickness measurements.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.04a
• /
• pp.205-206
• /
• 2014

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2018.11a
• /
• pp.361-362
• /
• 2018

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2018.05a
• /
• pp.361-362
• /
• 2018

• Progress in Medical Physics
• /
• v.15 no.1
• /
• pp.30-38
• /
• 2004

Purpose: To develop a whole body frame for the purpose of reducing patient motion and minimizing setup error for extra-cranial stereotactic radiotherapy, and to evaluate the repositioning setup error of a patient in the frame. Materials and Methods: The developed whole body frame is composed of a base plate, immobilizer, vacuum cushion, ruler and belts. The dimension of the base plate is 130 cm in length, 50 cm in width and 1 cm in thickness. The material used in the base plate of the frame was bakelite and the immobilizer was made of acetal. In addition, Radiopaque angio-catheter wires were engraved on the base plate for a coordinate system to determine the target localization. The measurement for radiation transmission and target localization is peformed in order to test the utilization of the frame. Also, a Matlab program analyzed the patients setup error by using the patient's setup images obtained from a CCTV camera and digital record recorder (DVR). Results: A frame that is useful for CT simulation and radiation treatment was fabricated. The frame structure was designed to minimize collisions from the changes in the rotation angle of the gantry and to maximize the transmission rate of the Incident radiation at the lateral or posterior oblique direction. The lightening belts may be used for the further reduction of the patient motion, and the belts can be adjusted so that they are not in the way of beam direction. The radiation transmission rates of this frame were measured as 95% and 96% at 10 and 21 MV, respectively. The position of a test target on the skin of a volunteer is accurately determined by CT simulation using the coordinate system in the frame. The estimated setup errors by Matlab program are shown 3.69$\pm$1.60, 2.14$\pm$0.78 mm at the lateral and central chest, and 7.11 $\pm$2.10, 6.54$\pm$2.22 mm at lateral and central abdomen, respectively. The setup error due to the lateral motion of breast is shown as 6.33$\pm$ 1.55 mm. Conclusion: The development and test of a whole body frame has proven very useful and practical in the radiosurgery for extra-cranial cancers. It may be used in determining target localization, and it can be used as a patient immobilization tool. More experimental data should be obtained in order to improve and confirm the results of the patient setup error.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.12 no.3
• /
• pp.396-405
• /
• 2009

The experimental research was conducted to setup a performance prediction logic for the regenerative cooling system on a small scale liquid rocket engine using kerosene and LOX. Total heat flux of the combustion gas side was determined for the flow rate of the coolant, combustion pressure using the calorimeter thrust chamber. Based on the experimental investigation, a performance prediction scheme for the regenerative cooling system is setup in our own way. A performance prediction logic for the regenerative cooling system has been developed by the correction scheme of the combustion gas side. The key parameters determining the temperature limitation of the coolant are the mass flow rate of the coolant and the length of the combustion chamber and the nozzle. And the parameters to control the limitation of the usable wall temperature are the number of channels and wall thickness.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2012.06a
• /
• pp.218-218
• /
• 2012

• Proceedings of the Optical Society of Korea Conference
• /
• 2001.02a
• /
• pp.194-195
• /
• 2001

We fabricated fiber bragg gratings using interferometric method with Phase mask. The interferometer consisted of two plane-parallel mirrors and a phase mask perpendicular to mirrors. The Gratings were written using an Argon-ion laser. The experimental setup could change Bragg wavelength given by the phase mask. (omitted)

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.255-260
• /
• 1993

This study proposed a new autofocusing method for a high resolution microscope with a depth of focus of a submicron range. The experimental setup was characterized by nulling method for bi-cell prhotodiode which had two active areas on sensor surface. The optical systems used in this method had was very simple and was easily matched to microscopes which had used widely. It was shown that the resolution was very high (about 20 nm) by experimental results. This method can be used in the semiconduct industry because it can find defects on the silcon wafer.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.65.5-65
• /
• 2002

$\textbullet$ Introduction $\textbullet$ Description of Prototype CRDM $\textbullet$ Theoretical Approach for estimating the gap variation between lift pole and lift armature $\textbullet$ Experimental Setup $\textbullet$ Experimental Results $\textbullet$ Conclusions