• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.82-93
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• 2000

Purpose: We characterized the signals obtained from the components of a small gamma camera using Nal(Tl)-position sensitive photomultiplier tube (PSPMT) and optimized the parameters employed in the modules of the system. Materials and Methods: The small gamma camera system consists of a Nal(Tl) crystal ($60{\times}60{\times}6mm^3$) coupled with a Hamamatsu R3941 PSPMT, a resister chain circuit, preamplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a resistive charge division circuit which multiplexes the 34 cross wire anode channels into 4 signals (X+, X-, Y+, Y -). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated and digitized via triggering signal and used to localize the position of an event by applying the Anger logic. The gamma camera control and image display was performed by a program implemented using a graphic software. Results: The characteristics of signal and the parameters employed in each module of the system were presented. The intrinsic sensitivity of the system was approximately $8{\times}10^3$ counts/sec/${\mu}Ci$. The intrinsic energy resolution of the system was 18% FWHM at 140 keV. The spatial resolution obtained using a line-slit mask and $^{99m}Tc$ point source were, respectively, 2.2 and 2.3 mm FWHM in X and Y directions. Breast phantom containing $2{\sim}7mm$ diameter spheres was successfully imaged with a parallel hole collimator. The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We proposed a simple method for development of a small gamma camera and presented the characteristics of the signals from the system and the optimized parameters used in the modules of the small gamma camera.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.69-76
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• 2010

Prototype double-scattering Compton camera, which consists of three gamma-ray detectors, that is, two double-sided silicon strip detectors (DSSDs) as scatterer detectors and a NaI(Tl) scintillation detector as an absorber detector, could provide high imaging resolution with a compact system. In the present study, the energy resolution and the timing resolution of component detectors were measured, and the parameters affecting the energy resolution of the DSSD were examined in terms of equivalent noise charge (ENC). The energy resolutions of the DSSD-1 and DSSD-2 were, in average, $25.2keV{\pm}0.8keV$ FWHM and $31.8keV{\pm}4.6keV$ FWHM at the 59.5 keV peak of $^{241}Am$, respectively. The timing resolutions of the DSSD and NaI(Tl) scintillation detector were 57.25 ns FWHM and 7.98 ns FWHM, respectively. In addition, the Compton image was obtained for a point-like $^{137}Cs$ gamma source with double-scattering Compton camera. From the present experiment, the imaging resolution of 8.4 mm FWHM (angular resolution of $8.1^{\circ}$ FWHM), and the imaging sensitivity of $1.5{\times}10^{-7}$ (intrinsic efficiency of $1.9{\times}10^{-6}$) were obtained.

• Investigative Magnetic Resonance Imaging
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• v.16 no.1
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• pp.55-66
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• 2012

Purpose : During brain MRI scanning, subject's head motion can adversely affect MRI images. To minimize MR image distortion by head movement, we developed an optical tracking system to detect the 3-D movement of subjects. Materials and Methods: The system consisted of 2 CCD cameras, two infrared illuminators, reflective sphere-type markers, and frame grabber with desktop PC. Using calibration which is the procedure to calculate intrinsic/extrinsic parameters of each camera and triangulation, the system was desiged to detect 3-D coordinates of subject's head movement. We evaluated the accuracy of 3-D position of reflective markers on both test board and the real MRI scans. Results: The stereo system computed the 3-D position of markers accurately for the test board and for the subject with glasses with attached optical reflective marker, required to make regular head motion during MRI scanning. This head motion tracking didn't affect the resulting MR images even in the environment varying magnetic gradient and several RF pulses. Conclusion: This system has an advantage to detect subject's head motion in real-time. Using the developed system, MRI operator is able to determine whether he/she should stop or intervene in MRI acquisition to prevent more image distortions.

• Korea Journal of Hospital Management
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• v.23 no.1
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• pp.41-50
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• 2018

The purpose of this research is to evaluate Brand Value by using the K-BPI(Korea Brand Power Index) of Korea Management Association which is based on consumer awareness, as well as to identify how Brand Value which is composed of top of awareness, unaided awareness, aided awareness, image, possibility of purchasing, preference, affects on the Market Share perceived by consumers. This research subjects were 10 hospitals with more than 1,000 beds in Seoul and Gyeonggi-do, and survey subjects were 20 or older adults living in the metropolitan area of Korea. Using K-BPI for measuring Brand Value and used calculation of Market Share according to consumer preference model for measuring Market Share. The major results of this research are as follows: First, this research identified that the top 5 hospitals of largest hospitals in metropolitan area measured by using K-BPI and Market Share were same hospitals as Big 4 hospitals of previous research evaluating the comprehensive competitiveness of hospitals and also same as hospitals that appeared recently. Second, Big 5 hospitals ranked first to fifth in both Brand Value and Market Share. To identify the relationship between K-BPI items(top of awareness, unaided awareness, aided awareness, image, availability, preference) and Market Share, multiple linear regression was used by dividing 5 upper and 5 lower group of hospitals per each. The group of 5 upper hospitals had a significant effect on Market Share, with 'top of awareness', 'unaided awareness', 'aided awareness'. The group of 5 lower hospitals had a significant effect on Market Share with 'unaided awareness', 'aided awareness'. The results of this study and hospitals of the first to third hospitals published in the K-BPI press release reported by KMAC in 2017, and the previous studies evaluating the comprehensive competitiveness hospitals, all had one thing in common that Big 4 hospitals ranked high position. This suggests that evaluation of Brand Value also can be a evaluation measure of hospital. A new competitiveness of hospital is expected by managing brand awareness to have a brand competitiveness and by securing intrinsic Market Share of consumer to reach hospital use ultimately.

• Fashion & Textile Research Journal
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• v.9 no.5
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• pp.538-544
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• 2007

We usually try to accomodate ourselves to our nature surroundings interacting with nature. There fore I've decided to apply nature materials, esp. the pine to Hair Art as a way of expressing our feelings from Nature. 'Hair Art' is a follow-up study based on the various artistic point of view. There has been various works of 'Hair Art' with nature materials. However, it is rare to see a work of 'Hair Art' with the pine. That's why I've decided to study more about this. This study is a new experiment in 'Hair Art' against a conventional idea "Hair Art values practicability." Therefore, the primary goal of this study is to do much for the cause of learning in 'Hair Art' and encourages some development of 'Hair Art' industry. I've researched an image of a pine tree in art of Joseon Dynasty and contemporary art. Then I've tried to apply the image to a work of 'Hair Art'. First of all, in a view of expression technique for the symbolism of the pine, the artists in Joseon Dynasty drew pictures of a pine tree with a paintbrush but the modern artists make a new attempt from the thought of Modernism. We can find it in some photos. Next, to express traditional oriental idea such as 'unconventional and elegance', comtemporary artists chose the symbolism of the pine tree as an object of their works like pen and ink sketches from the thought of Modernism. Third, in a fusion style picture which contains features of both oriental paintings and western paintings and in a sexualism style picture that depicts a harmony of a male and a female as a shape of a pine, we can find colorful images of a pine tree and Their figurative beauty in art. Those are another symbols of the pine. In conclusion, the implication of the pine tree still hasn't changed even there are differences of drawings of pine tree in the past and the present. I've tried to combine these symbolic ideas of the pine with 'Hair Art' and made 5 hair styles. Throughout the process of researching this topic which is 'The Study of Hair Art Using The Symbolism of The Pine', I've realized that pine trees make it possible to express intrinsic tough spirit of human being and abundance in color and figurative beauty in art. I hope this can contribute to the field of 'Hair Art' and would become an important educational resource for further study.

• Journal of Biomedical Engineering Research
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• v.20 no.1
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• pp.107-113
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• 1999

The purpose of this study was to develop a miniature imaging gamma probe with high performance that can detect small or residual tumors after surgery. Gamma probe detector system consists of NaI(Tl) scintillator, position sensitive photomultiplier tube (PSPMT), and collimator. PSPMT was optically coupled with 6.5 mm thick, 7.62 cm diameter of NaI(Tl) crystal and supplied with -1000V for high voltage. Parallel hexagonal hole collimator was manufactured for characteristics of 40-mm hole length, 1.3-mm hole diameter, and 0.22 mm septal thickness. Electronics consist of position and trigger signal readout systems. Position signals were obtained with summing, subtracting, and dividing circuit using preamplifer and amplifier. Trigger signals were obtained using summing amplifier, constant fraction discriminator, and gate and delay generator module with preamplifer. Data acquisition and processing were performed by Gamma-PF interface board inserted into pentium PC and PIP software. For imaging studies, flood and slit mask images were acquired using a point source. Two hole phantom images were also acquired with collimator. Intrinsic and system spatial resolutions were measured as 3.97 mm and 5.97 mm, respectively. In conclusion, Miniature gamma probe images based on the PSPMT showed good image quality, we conclude that the miniature imaging gamma probe was successfully developed and good image data were obtained. However, further studies will be required to optimize imaging characteristics.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.220-225
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• 2020

Hair is made of proteins containing various amino acids. Ultraviolet (UV) radiation is believed to be responsible for the most damaging effects of sunlight, and also plays an important role in hair aging. The purpose of this study was to investigate the changes in morphological and chemical structures after ultraviolet B (UVB) irradiation of human hair. The UVB-irradiated hair showed characteristic morphological and structural changes, compared to those of the normal hair. The result from a scanning electron microscope (SEM) equipped with an energy dispersive X-ray diffractometer (EDX) showed that the scale of UV-irradiated hair appeared to be rough and the amount of oxygen element was higher than that of the normal hair. Fluorescence and three dimensional (3D) topographical images were obtained by a confocal laser scanning microscope (CLSM). In 3D images, the green emission intensity of normal hair was much higher than that of fluorescing UVB-irradiated hair. The intensity of green emission reflects the intrinsic fluorescence of hair protein. Also, a fluorescent imaging method using fluorescamine reagent was used to identify the free amino groups resulting from a peptide bond breakage in UVB-irradiated hair. Strong blue fluorescence of UVB-irradiated hair, which indicates a very high level of amino groups, was observed by CLSM. Therefore, the fluorescamine as an extrinsic fluorescence could provide a useful tool to identify the peptide bond breakage in UVB-irradiated hair. Infrared image mapping was also employed to assess the cross-sections of normal and UVB-irradiated specimens to examine the oxidation of disulfide bonds. The degree of peak areas with strong absorbance for the disulfide mono-oxide was spread from the outside to the inside of hair. The spectroscopic techniques used alone, or in combination, launch new possibilities in the field of hair cosmetics.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.4
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• pp.61-72
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• 2014

Throughout analyzing and construing the words, contexts, and expressive languages used for depicting the pine tree in the novel "Honbul" written by Choi, Myung-Hee the symbolism of the pine and folksy languages used for scenery can be condensed as written below: First, it is explicit that the scenery-words for illustrating the pine tree in "Honbul" are emerged through diverse means methods and expressions. Namely, the reference forms of the pine tree and the expressive means of utilizing words portrays the use of the pine are various and subdivided. Second, the scenery-words found in vocabularies and the contexts of "Honbul" imply various symbolic representation. They not only perform to describe inherent image and symbolism of the pine, but they work for reifying the image of "Honbul" in the narrative structure in "Honbul" as being intrinsic scenery-word. Third, the scenery-words used for expressing aesthetics emerge as synesthetic expressions through the linear beauty and the texture of the pine as well as through five-senses. Forth, on the basis of the inherent symbolism and the image of the pine, the landscape of the background described in "Honbul" deems as a symbolic backdrop. As with then narrative structure of the novel, the pine tree performs as a mediation of the heaven and the earth, god and man, as well as the sacred and the secular. Fifth, scenery-words used for depicting the pine tree are a symbol that represents the spirit and emotion of the character in the novel. Moreover, it is a tool for pursuing the personification of the nature, the deification of the object, and the cosmos of the space. It is also utilized as a device that definitize the ideational image applied to express the landscape of the background of the novel. As mentioned above, the expressions, vocabularies and textures about pine tree represented from "Honbul" are expected to be the beginning of understanding the landscape-images and landscape-languages of pine in not only the setting for this novels, Namwon but also the entire districts of Korea.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.154-155
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• 2012

The promise of nano-crystalites (nc) as a technological material, for applications including display backplane, and solar cells, may ultimately depend on tailoring their behavior through doping and crystallinity. Impurities can strongly modify electronic and optical properties of bulk and nc semiconductors. Highly doped dopant also effect structural properties (both grain size, crystal fraction) of nc-Si thin film. As discussed in several literatures, P atoms or radicals have the tendency to reside on the surface of nc. The P-radical segregation on the nano-grain surfaces that called self-purification may reduce the possibility of new nucleation because of the five-coordination of P. In addition, the P doping levels of ${\sim}2{\times}10^{21}\;at/cm^3$ is the solubility limitation of P in Si; the solubility of nc thin film should be smaller. Therefore, the non-activated P tends to segregate on the grain boundaries and the surface of nc. These mechanisms could prevent new nucleation on the existing grain surface. Therefore, most researches shown that highly doped nc-thin film by using conventional PECVD deposition system tended to have low crystallinity, where the formation energy of nucleation should be higher than the nc surface in the intrinsic materials. If the deposition technology that can make highly doped and simultaneously highly crystallized nc at low temperature, it can lead processes of next generation flexible devices. Recently, we are developing a novel CVD technology with a neutral particle beam (NPB) source, named as neutral beam assisted CVD (NBaCVD), which controls the energy of incident neutral particles in the range of 1~300eV in order to enhance the atomic activation and crystalline of thin films at low temperatures. During the formation of the nc-/pm-Si thin films by the NBaCVD with various process conditions, NPB energy directly controlled by the reflector bias and effectively increased crystal fraction (~80%) by uniformly distributed nc grains with 3~10 nm size. In the case of phosphorous doped Si thin films, the doping efficiency also increased as increasing the reflector bias (i.e. increasing NPB energy). At 330V of reflector bias, activation energy of the doped nc-Si thin film reduced as low as 0.001 eV. This means dopants are fully occupied as substitutional site, even though the Si thin film has nano-sized grain structure. And activated dopant concentration is recorded as high as up to 1020 #/$cm^3$ at very low process temperature (＜ $80^{\circ}C$) process without any post annealing. Theoretical solubility for the higher dopant concentration in Si thin film for order of 1020 #/$cm^3$ can be done only high temperature process or post annealing over $650^{\circ}C$. In general, as decreasing the grain size, the dopant binding energy increases as ratio of 1 of diameter of grain and the dopant hardly be activated. The highly doped nc-Si thin film by low-temperature NBaCVD process had smaller average grain size under 10 nm (measured by GIWAXS, GISAXS and TEM analysis), but achieved very higher activation of phosphorous dopant; NB energy sufficiently transports its energy to doping and crystallization even though without supplying additional thermal energy. TEM image shows that incubation layer does not formed between nc-Si film and SiO2 under later and highly crystallized nc-Si film is constructed with uniformly distributed nano-grains in polymorphous tissues. The nucleation should be start at the first layer on the SiO2 later, but it hardly growth to be cone-shaped micro-size grains. The nc-grain evenly embedded pm-Si thin film can be formatted by competition of the nucleation and the crystal growing, which depend on the NPB energies. In the evaluation of the light soaking degradation of photoconductivity, while conventional intrinsic and n-type doped a-Si thin films appeared typical degradation of photoconductivity, all of the nc-Si thin films processed by the NBaCVD show only a few % of degradation of it. From FTIR and RAMAN spectra, the energetic hydrogen NB atoms passivate nano-grain boundaries during the NBaCVD process because of the high diffusivity and chemical potential of hydrogen atoms.

• Trans-
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• v.7
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• pp.19-48
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• 2019

This study was described to examine the meaning of the media exhibition work <70mK>, which aims to capture the topography of the collective consciousness of the Korean people through large-scale interviews. <70mK> edits and organizes interview images of individual beings in mosaic-like layouts and forms, creating video exhibitions and holding exhibitions. The objects in the split frame show the continuity of differences that reveal their own thoughts and personalities. This is a synchronic and conscious collective typology in which the intrinsic nature of the individuals is embodied in a simultaneous and holistic image. Interview images reveal their own form as a actual being and convey the intrinsic nature of one's own as oral information. <70mK> constructs a new individualization by aesthetically structuring the forms and information of life individuals in the extension of a specific group. The beings in the frame are not communicating with each other and are looking straight ahead. it conveys to visitors their relationship and personality as the preindividual reality. It is the repetitive arrangement and composition of heterogeneity and difference that each individual shows, and is a chain operation that includes collective identity behind it. <70mK> constructs the direct images and sounds of individual interviewee, creating a new form of information transfer called Video Art Exhibition. This makes metaphors and perceptions of the meaning and process of transindividual relationships and the meaning of psychic individuation and collective individuation. This is an appropriate case to explain with modern technology and individualization of Gilbert Simondon thought together with the meaning of becoming and relation of individualization. The exhibition space constructed by <70mK> is an aesthetic methodology of the psychic and collective meaning and its relationship to a particular group of individuals through which they are connected. Simondon studied the meaning of the process of individualization and the meaning of becoming, and is a philosopher who positively considered the potential of modern technology. <70mK> is a new individual as structured and generated ethical reality mediated by modern technology mechanisms and network behaviors. It is an case of an aesthetic and practical methodology of how interviews function as 'transduction' in the process of individualization in which technology is cooperated. The direct images and sounds of <70mK> are systems in which the information of life individuals is carried, amplified, accumulated and transmitted. It is also a new individual as a psychic and collective landscape. It is a newly became exhibition art work through the multiple individualization, and is a representation of transindividual meanings and process. The media exhibition art of individualized metastable states leads to new relationships in which viewers perceive the same preindividual reality and feel affectivity. The exhibition space of <70mK> becomes a stage for preparing the actual possibility of the transindividual group beyond the representation of the semantic function.