• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.5
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• pp.23-30
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• 2002

The PVDF (Polyvinylidene Fluoride) thin film having P phase is prepared by the vacuum deposition with applying the electric field and its pyroelectric properties are studied by using a dynamic method to examine the possibility of the application to the pyroelectric IR sensor. The pyroelectric responses of the PVDF thin film are characterized as the frequency dispersion in both low and high modulation frequency regions, and their frequency dependences are observed. In the low frequency region (2~10Hzz), the polarization can easily rotate with the increase of modulation frequency and show the maximum since the reorientation rate of domains is higher than the modulation frequency. On the other hand, in the high frequency region (100~1000Hz), the pyroelectric response decreases as the frequency increases, because the reorienatation rate of domains is suppressed and thus, the change of polarization decreases. Pyroelectric coefficient, figure of merits for noise equivalent power and detectivity of the PVDF thin film are measured as 3.2$\times$10$^{-10}$ C/$\textrm{cm}^2$.K, 2.34$\times$10$^{-10}$ C.cm/J and 1.32$\times$10$^{-9}$ C.cm/J, respectively. Also, the noise equivalent and the detectivity are 1.66$\times$10$^{-7}$ W/H $z^{$\sfrac{1}{2}$}$, 6.03$\times$10$^{5}$ cm.H $z^{$\sfrac{1}{2}$}$W, respectively.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.6
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• pp.9-15
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• 2004

PZT(30/70) thick film was fabricated by using 1,3 propanediol-based sol-gel method. Prepared film of pyroelectric property was investigated by Dynamic method of modulation frequency dependence. Pyroelectric coefficient was obtained about $5.0{\times}10^{-8}\;C/cm^2{\cdot}K$. The figure of merits for voltage responsively and specific detectivity were $3.4{\times}10^{-11}\;C{\cdot}cm/J$ and $5.9{\times}10^{-9}\;C{\cdot}cm/J$, respectively, because of relative high-dielectric constant and high-pyroelectric coefficient. Voltage responsively was increased at low modulation frequency and it was decreased at high modulation frequency. Voltage responsively was maximum 1.84 V/W at 10Hz. As Johnson noise is dominant, Noise voltage was increased nearly proportional to $f^{-1/2}$. Noise equivalent power and specific detectivity were $2.83{\times}10^{-7}\;W/Hz^{1/2}$ and 3.13{\times}10^5\;cm{\cdot}Hz^{1/2}/W$ the same frequency at 80Hz, respectively.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.12
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• pp.1008-1015
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• 2002

The fabricated La-modified lead titanate (PLT) thin film without poling treatment was investigated for modulation frequency dependence of pyroelectric properties by the dynamic method. $Pb_{l-x}La_{x}Ti_{l-x/4}O_3$(x=0.1) (PLT(10)) thin film haying 10 mol% La content was deposited on a Pt/$TiO_{x}$/$SiO_2$/Si substrate by sol-gel method. The PLT(10) thin film exhibits a relatively excellent dielectric property. The pyroelectric coefficient (p) of the PLT(10) thin film is 6.6 x $10^{-9}C$$textrm{cm}^2$$.$K without frequency dependence. The figure of merits for the voltage responsivity and specific detectivity are 1.03 x $10^{-11}C$.cm/J and 1.46 x $10^{-10}C$.cm/J, respectively The PLT(10) thin film has voltage responsivity (RV) of 5.IS V/W at 8 Hz. Noise equivalent power (NEP) and specific detectivity ($D^{*}$) of the PLT(10) thin film are 9.93 x $10^{-8}$W/$Hz^{1/2}$ and 1.81 x $10^{6}$cm.$Hz^{1/2}$/W at the same frequency of 100 Hz,, respectively The results means that PLT thin film having 10 mol% La content is suitable for the sensing materials of pyroelectric IR sensors.

• The Journal of Korean Philosophical History
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• no.31
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• pp.53-86
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• 2011

Taoism exercised its influence and has made much progress apparently under the aegis of the Tang dynasty. But since the external alchemy, a traditional way of eternal life that they have pursued, met the limitation, they were placed in a situation where they needed to seek a new discipline. From this period to the early North Song dynasty, three religions have established the unique theoretical systems of their own theory of ascetic practices. They showed their own unique formats as follows. Neo-Confucianism established the theory of moral training, Buddhism did the theory of ascetic practices and Taoism had theory of discipline. By this time, a person who claimed the Intermixture of Three Religions composed the new system of theory of ascetic practice by taking advantage of other religions and putting them into his own view. Chen tuan established the theory of internal alchemy of Taoism and was the most influential figure in the world of thought since North Song dynasty. He clearly declared that he accepted the merits of other religions in his theory. He added I Ching of Confucianism in I Ching of secret of Taoism to stop the logical gaps during the process of disciplines in Taoism and took ascetic practices on mind of Buddhism into his system while he sought a way to integrate the dual structure of body and mind. The theory of Chen tuan's internal alchemy was training schema with stages of 'YeonJeongHwaGi', 'YeonGiHwaSin', and 'YeonSinHwanHeo' based on the concepts of vital, energy and spirit. The internal alchemy practice that Chen tuan was saying started from the practice of Zen to keep the mind calm with the basis of fundamental principles of interpretation of book of change according to Taoism. When a person reached the state to be in concert with all changes at the end of the silence and be full of wisdoms, he finally returned to the state of BokGwiMuGeuk by taking the flow of subtle mind and transforming it into energy. He expressed this process by drawing 'MuGeukDo'. Oriental philosophy categorized human into 'phenomenal existence' and 'original existence'. The logic of theory of ascetic practice has been established from these 'category of existence'. It would be determined whether it will return to 'original existence' or be stepped up from 'phenomenal existence' according to how the concept of 'self' or 'I' was made. Chen tuan who established the theory of internal alchemy in Taoism has established the unique theory of internal alchemy discipline and system of intermixture of three religions in this aspect. Today is called 'era of self-loss' or 'era of incurable diseases' caused by environmental pollution. It's still meaningful to review the theory of discipline of Chen tuan's connecting the body and the soul to heal the self, and keep life healthy and pursue the new way of discipline based on it.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.54-60
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• 2010

Purpose: Nuclear medicine manufacturers provide various softwares which shorten imaging time using their own image processing techniques such as UlatraSPECT, ASTONISH, Flash3D, Evolution, and nSPEED. Seoul National University Hospital has introduced softwares from Siemens and Philips, but it was still hard to understand algorithm difference between those two softwares. Thus, the purpose of this study was to figure out the difference of two softwares in planar images and research the possibility of application to images produced with high energy isotopes. Materials and Methods: First, a phantom study was performed to understand the difference of softwares in static studies. Various amounts of count were acquired and the images were analyzed quantitatively after application of PIXON, Siemens and ASTONISH, Philips, respectively. Then, we applied them to some applicable static studies and searched for merits and demerits. And also, they have been applied to images produced with high energy isotopes. Finally, A blind test was conducted by nuclear medicine doctors except phantom images. Results: There was nearly no difference between pre and post processing image with PIXON for FWHM test using capillary source whereas ASTONISH was improved. But, both of standard deviation(SD) and variance were decreased for PIXON while ASTONISH was highly increased. And in background variability comparison test using IEC phantom, PIXON has been decreased over all while ASTONISH has shown to be somewhat increased. Contrast ratio in each spheres has also been increased for both methods. For image scale, window width has been increased for 4~5 times after processing with PIXON while ASTONISH showed nearly no difference. After phantom test analysis, ASTONISH seemed to be applicable for some studies which needs quantitative analysis or high contrast, and PIXON seemed to be applicable for insufficient counts studies or long time studies. Conclusion: Quantitative values used for usual analysis were generally improved after application of the two softwares, however it seems that it's hard to maintain the consistency for all of nuclear medicine studies because result images can not be the same due to the difference of algorithm characteristic rather than the difference of gamma cameras. And also, it's hard to expect high image quality with the time shortening method such as whole body scan. But it will be possible to apply to static studies considering the algorithm characteristic or we can expect a change of image quality through application to high energy isotope images.