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Performance Evaluation of a Pinhole Collimator According to the Aperture Diameter (핀홀 콜리메이터 초점의 직경 크기 별 성능비교 및 평가)

  • Lee, Kwang Hun;An, Byung Ho;Kim, Soo Young;Choi, Sung Wook
    • The Korean Journal of Nuclear Medicine Technology
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    • v.18 no.1
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    • pp.104-109
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    • 2014
  • Purpose: Conventional pinhole scintigraphy offers a high resolution and generally use for thyroid scan or bone scintigraphy. the aim of this study is to evaluate performance of each aperture according to the diameter size. Materials and Methods: In this study 2 mm, 4 mm, 6 mm, 8 mm diameter pinhole collimators were mounted on Siemens E.CAM systems. In order to evaluate performance evaluation of each aperture, we acquired projection image by using SPECT for evaluating FWHM, resolution test and static image for evaluating thyroid phantom test. Results: As a result of FWHM showed 2.2 mm FWHM, 3.2 mm FWHM, 5.4 mm FWHM, 7.5 mm FWHM per each aperture in the resolution test. SNR, uniformity, contrast were acquired result from thyroid phantom test comparing general image and delayed image. as a result of SNR showed 6.55, 8.47, 6.2, 5.23 in case of general image and 5.25, 5.01, 5.38, 5.82 in case of delayed image per each aperture. as a result of uniformity showed 0.152, 0.118, 0.161, 0.19 in case of general image and 0.19, 0.199, 0.185, 0.171 in case of delayed image per each aperture. as a result of contrast showed 1.31, 1.19, 1.15, 1.01 in case of general image and 1.09, 1.08, 1.04, 1 in case of delayed image per each aperture. Conclusion: Resolution and sensitivity were heavily influenced by aperture size. and also we found advantage of delayed image as a result of thyroid phantom test.

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Abosrbed Dose Measurements and Phantom Image Ecaluation at Minimum CT Dose for Pediatric SPECT/CT Scan (소아 SPECT/CT 검사를 위한 최저조건에서의 피폭선량측정 및 팬텀의 영상평가)

  • Park, Chan Rok;Choi, Jin Wook;Cho, Seong Wook;Kim, Jin Eui
    • The Korean Journal of Nuclear Medicine Technology
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    • v.18 no.1
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    • pp.82-88
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    • 2014
  • Purpose: The purpose of study was to evaluate radiation dose for pediatric patients by changing tube voltage (kVp) and tube current (mA) at minimum conditions. By evaluating radiation dose, we want to provide dose reduction for pediatric patients and maintain good quality of SPECT/CT images. Materials and Methods: Discovery NM/CT 670 Scanne was used as SPECT/CT. Tube voltages are 80 and 100 kvP. Tube currents are 10, 15, 20, 25 mA. Using PMMA (Polymethyl methacrylate) Phantom, radiation dose which were calculated at center and peripheral dose and SNRD (Signal to Noise Ratio Dose) were evaluated. Using the CT performance phantom, spatial resolution was evaluated as the MTF (Modulation Transfer Function) graph. Jaszczak phantom was used for SPECT image evaluation by CNR (Contrast to Noise to Ratio). Results: Radiation dose using the PMMA phantom was higher peripheral dose than center dose about 7%. SNRD were 7.8, 8.2, 8.3, 8.8, 8.8, 9.9, 9.8, 9.6 for 80 kVp 10, 15, 20, 25 mA, 100 kVp 10, 15, 20, 25 mA. We can distinguish 35, 45, 70, 71, 52, 58, 90, 110 linepair for 80 kVp 10, 15, 20, 25 mA, 100 kVp 10, 15, 20, 25 mA at resolution with MTF. CNR of SPECT images using CT attenuation map were 57.8, 57.7, 57.1, 56.7, 56.6, 56.7, 56.7, 56.7% for 80 kVp 10, 15, 20, 25 mA, 100 kVp 10, 15, 20, 25 mA. Conclusion: In this study, radiation dose for pediatric patients showed decreased low dose condition. And SNRD value was similar in all condition. Resolution showed higher value at 100kVp than 80kVp. for CNR, there was no significant difference. we should take additional study to prove better quality and dose reduction.

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Effects of Polyimide Passivation Layers and polyvinylalcohol Passivation Layers for Organic Thin-Film Transistors(OTFTs) (폴리이미드 패시베이션과 폴리비닐알콜 패시베이션 레이어 성막이 고성능 유기박막 트렌지스터에 주는 영향)

  • Park, Il-Houng;Hyung, Gun-Woo;Choi, Hak-Bum;Hwang, Sun-Wook;Kim, Young-Kwan
    • Journal of the Korean Vacuum Society
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    • v.17 no.3
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    • pp.195-198
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    • 2008
  • In this paper, it was demonstrated that organic thin-film transistors (OTFTs) were fabricated with the organic passivation layer by vapor deposition polymerization (VDP) processing. In order to form polymeric film as a passivation layer, VDP process was also introduced instead of spin-coating process, where polymeric film was co-deposited by high-vacuum thermal evaporation from 6FDA and ODA followed by curing. In order to investigate by compared with different passivation layer, the other OTFTs is fabricated to passivation by Polyvinylalcohol using spincoating. We can see that two different ways of passivation layer affect electric characteristic of OTFTs. The initial electric characteristic of OTFTs before passivation such as field effect mobility, threshold voltage, and on-off current ratio are $0.24cm^2/Vs$, -3V, and $10^6$, respectively. Then after polyimide passivation layer, field effect mobility change from $0.24cm^2/Vs$ to $0.26cm^2/Vs$, threshold voltage from -3V to 1V and on-off current ratio from $10^6$ to $10^6$, respectively. In the case of polyvinylalcohol passivation, the initial electric characteristic of OTFTs before passivation such as field effect mobility, threshold voltage, and on-off current ratio are $0.13cm^2/Vs$, 0V, and $10^6$, respectively. Then after polyvinylalcohol passivation layer, field effect mobility changes from $0.13cm^2/Vs$ to $0.13cm^2/Vs$, threshold voltage from 0V to 2V, and on-off current ratio from $10^6$ to $10^5$, respectively.

Deterimination of an Optimal Time Point for Analyzing Transcriptional Activity and Analysis of Transcripts of Avian Influenza Virus H9N2 in Cultured Cell (배양세포에서 Semi-quantitative RT-PCR에 의한 조류인플루엔자 H9N2의 전사활성 분석 최적 시기 결정 및 전사체 분석)

  • Na, Gi-Youn;Lee, Young-Min;Byun, Sung-June;Jeon, Ik-Soo;Park, Jong-Hyeon;Cho, In-Soo;Joo, Yi-Seok;Lee, Yun-Jung;Kwon, Jun-Hun;Koo, Yong-Bum
    • Korean Journal of Microbiology
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    • v.45 no.3
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    • pp.286-290
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    • 2009
  • The transcription of mRNA of avian influenza virus is regulated temporally during infection. Therefore, the measurement of transcript level in host cells should be performed before viral release from host cells because errors can occur in the analysis of the transcript levels if the viruses released from the infected cells re-infect cells. In this study, the timing of viral release was determined by measuring the level of viral RNA from viruses released from H9N2-infected chicken fibroblast cell line UMNSAH/DF-1 by semi-quantitative RT-PCR. The viral genomic RNA was isolated together with mouse total RNA which was added to the collected medium as carrier to monitor the viral RNA recovery and to use its GAPDH as an internal control for normalizing reverse transcription reaction as well as PCR reaction. It was found that viral release of H9N2 in the chicken fibroblast cell line UMNSAH/DF-1 took between 16 and 20 h after infection. We measured all 8 viral mRNA levels. Of the 8 transcripts, 7 species of viral mRNAs (each encoding HA, NA, PB1, PB2, NP, M, NS, respectively) except PA mRNA showed robust amplification, indicating these mRNA can be used as targets for amplification to measure transcript levels. These results altogether suggest that the method in this study can be used for screening antiviral materials against viral RNA polymerase as a therapeutic target.

Study on Waxy Corn X. Analysis on Botanical Characteristics, Physicochemical Properties Related to Table Qualities of the Developed Waxy Corn Hybrids (찰옥수수 연구 X. 육성된 찰옥수수 교잡종의 식물학적 특성 및 식미관련 이화학적 형질)

  • Lee, Moon-Sub;Bok, Tae-Gyu;Choi, Yun-Pyo;Hong, Bom-Young;Jo, Yang-Hee;Lee, Hee-Bong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.56 no.1
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    • pp.8-13
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    • 2011
  • This study was carried out to compare botanical characteristics, physicochemical properties related to table quality and feed values and develop a new variety among 12 developed waxy com hybrids. These materials were produced in 2008 and cultivated in 2009 at Com Breeding and Genetics Farm of Coll. of Agri. & Life Sci., Chungnam Nat'l Univ. Botanical characteristics of used waxy com hybrids showed large difference among hybrids; stem height, ear height and ear length. In physical properties, range of kernel sugar content among used hybrids appeared 16.1 to 13.0brix(%). CNU08H-15, CNU08H-35 and CNU08H-h39 among these were highly appeared as 15 above and pericarp thickness of Yeonongchal was very thick as $46.0{\mu}m$, while CNU08H-39 among hybrids showed the thinnest as $23.0{\mu}m$ compared to other hybrids. Protein content as a indicator of table quality was the highest in Ilmichal among hybrids, while that of CNU08H-39 was the lowest, while amylopectin content was the highest as 94.5%, From experimental results, Daehakchal Gold 1, CNU08H-h121 and CNU08H-39 including check Yeonyoungchal were highly evaluated as new hybrid in thinner pericarp, high amylopectin and chewiness.

The Uptake of $Sr^{90}$ by Paddy Rice from Soil and its Distribution in the Plant (답토양(畓土壤)에서 수도(水稻)의 Strontium-90 흡수(吸收)와 수도체내(水稻體內) 분포(分布))

  • Lim, Soo-Kil;Kim, Jae-Sung;Lee, Young-Il
    • Korean Journal of Environmental Agriculture
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    • v.5 no.1
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    • pp.48-54
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    • 1986
  • Because of the drastic development of nuclear industries, the contamination of natural environments by the disposal of radioactive materials which are released from nuclear facilities have aroused a considerable concern in relation to agricultural practices. Therefore the present investigation, through pot experiment, was performed to find out the aspect of the uptake of $Sr^{90}$ by rice plants and its distribution in them in five different types(physicochemical and minerallogical properties) of paddy soils. The results obtained were as follows; 1) Visual toxic symptoms on the growth of rice plant due to treatment of $Sr^{90}$ up to $40{\mu}Ci/10㎏$ in a pot were not observed even though uptake of $Sr^{90}$ by rice plant was proportionally increased with the $Sr^{90}$ treatment. 2) Distribution of $Sr^{90}$ in the rice plant was the highest in the leaves (84.5%) followed in the order by stems (13.5%) and rough grain (2.0%). The ratio of $Sr^{90}$ to Ca was higher in the leaves (872) and stems (667) than in the rice grain (89). 3) $Sr^{90}$ absorption in the rice plant ranged $0.15{\sim}0.30%$ at harvesting time. Uptake of $Sr^{90}$ by rice plants decreased by the increase of soil pH and exchangeable canons in the soils, but $Sr^{90}$ uptake increased when nitrogen, organic matter and clay content in soil was high, and uptake of this nuclide in the rice plant was higher with low Illite and Vermiculite content in the soils.

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A STUDY ON THE MODE OF POLYMERIZATION OF LIGHT-CURED RESTORATIVE MATERIALS CURED WITH PLASMA ARC LIGHT CURING UNIT (Plasma arc light curing unit을 이용한 광중합형 수복재의 중합양상)

  • Woo, Youn-Sun;Jeong, Tae-Sung;Kim, Shin
    • Journal of the korean academy of Pediatric Dentistry
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    • v.29 no.2
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    • pp.262-269
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    • 2002
  • The purpose of this study was to compare the effect of distance of light tip to resin surfaces and exposure time on the polymerization of surface and 2 mm subsurface of composite resins cured with two light sources; conventional halogen light (XL 3000, 3M, U.S.A.) and plasma arc light (Flipo, LOKKI, France) and compare the uniformity of polymerization from the center to the periphery of resin surfaces according to polymerization diameter cure with two light sources. From the experiment, the following results were obtained. 1. Difference of relative light intensity decrease in plasma arc light smaller than that of conventional halogen light(p<0.05). 2. In all groups, microhardness of top surfaces was decreased when distance of the light tip to resin surfaces is more than 2mm and increased according to increase of exposure time(p<0.05). 3. Difference of microhardness of the 2mm subsurface was rapidly decreased when distance of light tip to resin surfaces is more than 4mm(except, plasma arc light exposure time of 3 seconds). and the distance of light tip to resin surfaces and exposure time more affected 2mm subsurface rather than top surface(p<0.05). 4. Although exposure time was increased, difference of microhardness of the 2mm subsurface with the distance of light tip to resin surfaces was relatively high in groups between below 4mm and 6 mm(p<0.05). 5. Plasma arc light exposure time of 6 to 9 seconds produced microhardness values and microhardness change according to various distance similar to those produced with 40 to 80 second exposure to a conventional halogen light(p>0.05). 6. In all groups, microhardness was decreased gradually from the center to the periphery of resin surfaces(p<0.05).

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An Analysis of Elementary Students' Attention Characteristics through Attention Test and the Eye Tracking on Real Science Classes (실제 과학수업에서 시선추적과 주의력 검사를 통한 초등학생들의 주의 특성 분석)

  • Shin, Won-Sub;Shin, Dong-Hoon
    • Journal of The Korean Association For Science Education
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    • v.36 no.4
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    • pp.705-715
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    • 2016
  • The purpose of this research is to analyze elementary students' attention characteristics through attention test and eye tracking on real science classes. The SMI's ETG(eye tracker glasses) mobile eye tracker was used to analyze the attention process of elementary students'. The sampling rate of the ETG is 30Hz. The participants of attention test were elementary 155 6th-grade elementary students and the participants for the eye-tracker were six 6th-grade male students. The eye movements were analyzed using the 'BeGaze Mobile Video Analysis Package' program. The results of this research are as follows. First, the attention test results of elementary students showed high correlation between selective attention and sustained attention (.85) and low correlation between selective attention and self-regulation (.32). Second, the attention types of elementary students were divided into four; attention, inattention, easygoing and hasty. Third, elementary students' attention were divided into top-down, bottom-up, default mode network through analysis of elementary students′ eye-movements during real science classes. Also their attention shift occurred frequently due to various reasons in real class situation. There were three reasons that made elementary students fail to handle knowledge-dependent top-down attention; 1) the cognitive failure of target caused by failing to focus attention, 2) the absence of prior knowledge on target object, 3) the analogical failure of prior knowledge. Finally, elementary students' attention process were schematized based on the analysis of students' eye movements and attention test. This research is expected to be utilized as basic data for developing effective teaching strategies, teaching-learning models and instructional materials.

Evaluating the Removal Efficiency of Organic Compounds and Nitrogen Depending on Loading Rate in Wastewater Treatment from Fisheries Processing Plant Using an Entrapped Mixed Microbial Cell Technique (미생물 강제포획기술을 이용한 수산물 가공공장 폐수처리에서 부하율에 따른 유기물 및 질소의 제거 효율성 평가)

  • Jeong Byung-Cheol;Chang Soo-Hyun;Jeong Byung-Gon
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.9 no.1
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    • pp.14-20
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    • 2006
  • In this study, the feasibility of simultaneous removal of organic materials and nitrogen in the waste-water from fisheries processing plant was evaluated using entrapped mixed microbial cell technique(EMMC) process. The experiment was performed using activated sludge from municipal sewage treatment plant which was immobilized with gel matrix by cellulose triacetate. It was found that the stable operation at the treatment system which is composed of anoxic and oxic tank, was possible when the organic and nitrogen loading rates were increased stepwise. The organic and nitrogen loading rates were applied from 0.65 to $1.72kgCOD/m^3/d$ and from 0.119 to $0.317kgT-N/m^3$ with four steps, respectively. The maximum nitrogen loading rate which could satisfy the regulated effluent standard of nitrogen concentration, was $0.3kgT-N/m^3/d$. The removal efficiency of total nitrogen was decreased apparently as increasing nitrogen loading rates, whereas the removal efficiency of ammonium nitrogen was effective at the all tested nitrogen loading rates. Therefore, it was concluded that nitrification was efficient at the system. Nitrate removal efficiency ranged from 98.62% to 99.51%, whereas the nitrification efficiency at the oxic tank ranged 94.0% to 96.9% at the tested loading rates. The removal efficiencies of chemical oxygen demand(COD) and those of total nitrogen at the entire system ranged from 94.2% to 96.6% and 73.4% to 83.4%, respectively.

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Effect of Fragment Removal on Development of Human Fragmented Embryos in IVF-ET Program (IVF-ET 시술 시 파편제거가 파편화된 인간배아의 발달에 미치는 효과)

  • Chi, Hee-Jun;Koo, Jung-Jin;Lee, Ju-Ok;Ryu, Hyoung-Eun;Kim, Kwang-Rae;Park, Chan;Roh, Sung-Il
    • Clinical and Experimental Reproductive Medicine
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    • v.37 no.4
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    • pp.339-348
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    • 2010
  • Objective: To investigate the beneficial effect of fragment removal on the subsequent cell division and clinical outcome of the fragmented human embryos. Methods: A prospective study was performed in Hanna Women's Clinic and Mizmedi Hospital. Sixty couples undergoing In vitro fertilization-embryo transfer (IVF-ET) program were participated in the present study. The microsurgical fragment removal was performed in 106 fragmented embryos of 29 patients before the transfer. As a control group, 122 fragmented embryos of 31 patients were transferred without the fragment removal. Effects of fragment removal on morphological changes and clinical outcomes of fragmented embryos were investigated. Results: Mean morphological grade (G2.79) of fragmented embryos was significantly improved after the fragment removal(G1.63, p<0.001). Most of the fragmented embryos did not show a regeneration of fragments after the fragment removal during the subsequent development, and a beneficial effect of fragment removal on the development of the fragment removed embryos was observed. Implantation and pregnancy rates of fragment removed embryos were 12.3% and 31.3%, whereas the rates of control group embryos were 6.6% and 22.5%, respectively. There was no statistical significance in the rates between the two groups because of the low number of trials. Conclusion: Microsurgical fragment removal improved the subsequent development as well as the morphological grade of fragmented embryos. The fragment removal may be beneficial for neighboring blastomeres by repairing the intercellular communication and removing the secretion of the potential toxic materials by fragments.