• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.324-327
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• 2003

The needs for the cryocooler which has high reliability and long MTTF are increased in the military and commercial thermal imaging system The gas contamination wear, leakage of the working fluid, fatigue and etc. have the significant effects on the reliability and MTTF(Mean Time To Failure) or MTBF(Mean Time Between Failure) of the Stirling cryocooler. In the KIMM, the Stilting cryocooler with the linear compressor was released after the several performance tests were performed. This paper describe the experimental facility for the MTTF evaluation and some typical results of the Stilling cryocooler.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.320-323
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• 2003

This paper presents the results of a series of performance tests for the Stilting cryocooler. A free piston and free displacer(FPFD) Stilting cryocooler for cooling infrared and cryo-sensors is currently under development at KIMM. Our coolers are specifically designed to work in the thermal imaging device and to meet requirements such as cooling capacity, COP and high reliability. In this work, Stilting cryocooler is designed, manufactured and fabricated, and performance characteristics for the cooling capacity / applied input power and cool down time are investigated. This cooler delivers approximately 0.9W cooling at 80K for 30W ~ 40W of input power. And, It takes approximately 2 minutes to cool down to 80K at the ambient temperature of 23$^{\circ}C$.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.167-170
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• 2003

This paper presents the results of a series of performance tests for the Stilting cryocooler. A free piston and free displacer(FPFD) Stilting cryocooler for cooling infrared and cryo-sensors is currently under development at KIMM. Our coolers are specifically designed to work in the thermal imaging device and to meet requirements such as cooling capacity, COP and high reliability. In this work, Stilting cryocooler is designed, manufactured and fabricated, and performance characteristics for the vibration, acoustic noise, EMI and leak rate are evaluated. Vibration outputs are measured to 20KHz for compressor and expander, respectively. And, the objective of noise test is a noise level, less than 30㏈ at 5 m. EMI tests are carried out according to the standard MIL-STD-461C tests RE01 and RE02. Leak test for the Stilting cryocooler is performed by bombing method.

• Journal of Korean Medical Ki-Gong Academy
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• v.14 no.1
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• pp.52-62
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• 2014

Objective : The aim of this study is to analyze the effectiveness of Korean Medicine treatment on post-hysterectomy syndrome patients by thermographic change during treatment. Methods : 5 female patients who had a hysterectomy within a year were treated with Korean Medicine concluding acupuncture, herbal medicine, cupping therapy, herbal bath. We evaluated the thermographic differences by checking Digital Infrared Thermal Imaging(D.I.T.I.) at CV17(膻中), CV4(關元), ST3(巨髎), BL15(心兪), and BL23(腎兪). Results : In consequence of Korean Medicine Treatment for 3 weeks, thermographic differences between CV17(膻中) and CV4(關元), ST3(巨髎) and CV4(關元), BL15(心兪), and BL23(腎兪) tended to decrease. Conclusion : After Korean Medicine treatment, thermographic differences between upper body and lower body tended to decrease cause shangrexiahanzheng(上熱下寒證) made by hysterectomy became moderated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.160-163
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• 2009

최근 적외선 열 영상의 유용함이 발표되어감에 따라 이 기술에 대한 이해와 도입폭이 점진적으로 넓혀져 가고 있다. 국내는 물론 세계적으로 많은 제조, 개발 관련 업체들이 생겨나고 있으며, 업체들의 기술이 발전함에 따라 높은 온도 분해능과 해상도는 물론, 시스템 전체의 크기가 휴대가 가능할 정도로 소형화 되어가고 있는 추세이다. 이러한 열 영상 카메라에서 중요한 역할을 하는 적외선 열 감지 센서에서는 주변 온도, 대상 온도, 표면 온도 등의 측정 오차 및 열상 측정 소자의 온도, Bias 불안정 등의 매우 다양한 원인으로 인한 잡음이 발생하기 쉽다. 이러한 다양한 잡음의 감소는 해상도 및 온도 분해능의 향상과 직결되므로, 잡음을 줄이기 위한 많은 연구가 도처에서 행해지고 있다. 본 논문은 이러한 노력의 일환으로써 각각의 잡음 원인을 규명하지 않고 최종 열 영상 출력물에서 인접 프레임들의 비교, 혼합 하여 제거하는 3D Noise Reduction 기술을 이용해 노이즈를 감쇠하는 방법에 대해 연구하였다.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.172-174
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• 2003

Using MODIS data and several different compositing algorithms utilizing the average cloud free days in a compositing period, maximum ndvi, or dual maximum NDVI/minimum blue, multi resolution composites (250m, 500m, 1km) have been produced for Southeast Asia, with spectral bands ranging from the visible to short-wave infrared with a single band in the thermal (for land and sea surface temperature). A total of nine composites have been produced for the months of May and August in 2003, including blue, green, red, NIR, three in the SWIR, and several to specifically monitor vegetation health.

• Journal of the Optical Society of Korea
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• v.9 no.4
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• pp.157-161
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• 2005

Medical infrared imaging is obtained by measuring the self-emitted infrared radiance from the human body. Infrared emission is related to surface temperature and temperature is one of the most important physiological parameters related to health. Though recent applications such as security identification and oriental medicine have provided new fields of biomedical applications, infrared thermography has had ups and downs in its usages in cancer detection. Some of the main difficulties include finding proper applications and efficient diagnostic algorithms. In this study, infrared thermal imaging was used to detect regional metastasis of breast cancer. Our measurements were done for 110 women. From 63 individuals of a Healthy Group and a Benign Breast Disease Group, we developed algorithms for differentiating malignant regional metastasis based on temperature difference and asymmetry of temperature distribution. Testing with 47 cancer patients, we achieved a positive predictive value of $87.5\%$ and a negative predictive value of $95.6\%$. The results were better than for mammogram examination. A proper analysis of infrared imaging proved to be a highly informative and sensitive method for differentiating regional cancer metastasis from normal regions.

• Current Optics and Photonics
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• v.6 no.1
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• pp.69-78
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• 2022

A high-resolution camera is a precise optical system. Its vibrations during transportation and launch, together with changes in temperature and gravity field in orbit, lead to different degrees of defocus of the camera. Thermal refocusing is one of the solutions to the problems related to in-orbit defocusing, but there are few relevant thermal refocusing mathematical models for systematic analysis and research. Therefore, to further research thermal refocusing systems by using the development of a high-resolution micro-nano satellite (CX6-02) super-resolution camera as an example, we established a thermal refocusing mathematical model based on the thermal elasticity theory on the basis of the secondary mirror position. The detailed design of the thermal refocusing system was carried out under the guidance of the mathematical model. Through optical-mechanical-thermal integration analysis and Zernike polynomial calculation, we found that the data error obtained was about 1%, and deformation in the secondary mirror surface conformed to the optical index, indicating the accuracy and reliability of the thermal refocusing mathematical model. In the final ground test, the thermal vacuum experimental verification data and in-orbit imaging results showed that the thermal refocusing system is consistent with the experimental data, and the performance is stable, which provides theoretical and technical support for the future development of a thermal refocusing space camera.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.193-200
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• 2006

To perform the finish grinding process of ferrules which are widely used as fiber optic connectors, a high-precision centerless grinding machine is necessary. The high-precision centerless grinding machine is consisted of the hydrostatic GW and RW spindle systems, hydrostatic RW feeding mechanism, RW swivel mechanism, on-machine GW and RW dressers, and concrete-filled steel bed. In this study, the thermal characteristics of the high-precision centerless grinding machine such as the temperature distribution, temperature rise and thermal deformation, are estimated based on the virtual prototype of the grinding machine and the heat generation rates of heat sources related to the machine operation conditions. The reliability of the predicted results is demonstrated by the temperature characteristics measured from the physical prototype. Especially, the predicted and measured results show the fact that the high-precision centerless grinding machine has very stable thermal characteristics.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.167-175
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• 2001

Semiconductor diode detectors coated with neutron reactive material are presently under investigation for various uses, such as remote sensing of thermal neutrons, fast neutron counting, and thermal neutron radiography. Theory indicates that single-coated devices can yield thermal neutron efficiencies from 4% to 11 %, which is supported by experimental evidence. Radiation endurance measurements indicate that the devices function well up to a limiting thermal neutron fluence of $10^{13}/cm^2$, beyond which noticeable degradation occurs. Thermal neutron contrast images of step wedges and simple phantoms, taken with dual in-line pixel devices, show promise for thermal neutron imaging detectors.