• Journal of Sensor Science and Technology
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• v.13 no.3
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• pp.182-187
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• 2004

The fluorinated amorphous carbon thin films (a-C:F) were deposited by PECVD(plasma enhanced chemical vapor deposition). The precursors were $C_{4}F_{8}$ which had a similar ratio of target film's carbon to fluorine ratio, and $Si_{2}H_{6}$/He for capturing excessive fluorine ion. We varied deposition condition of temperature and working pressure to survey the effect of each changes. We measured dielectric constant, composition, and etc. At low temperature the film adhesion to substrate was very poor although the growth rate was very high, the growth rate was very low at high temperature. The EDS(energy dispersive spectroscopy) result showed carbon and fluorine peak for films and Si peak for substrate. There was no oxygen peak.

• Journal of Applied Reliability
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• v.11 no.3
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• pp.293-303
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• 2011

Reliability Prediction using MIL-HDBK-217F has some restrictions due to its one modeling basis. One of the restrictions is caused by selecting one operating environment of a system, which is chosen regardless of its detailed conditions, e.g., external impact and vibration. Especially, an equipment, which is installed on a mobile vehicle though its movement is quasi-static, is controversial to designate its environment as ground mobile($G_M$), rather than ground fixed($G_F$). In this paper, failure rates were compared, which are computed using several moving time rates to total operating time. RiAC-HDBK-217Plus was used as the basic calculation model. In addition, $G_F$ conditioned failure rate was evaluated by comparing with that under $G_M$ environment but fixed state.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.141-144
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• 2006

본 논문은 적응형 육각 탐색에 기반한 고속 블록 정합 알고리즘의 성능 개선에 관한 것으로, 이전 프레임의 움직임 활동도를 산출한 후, 웨이블렛 변환의 다단계 저주파 부영상들로 구성된 피라미드 계층 구조상에서 이 움직임 활동도에 따라 초기 움직임 탐색 계층을 적응적으로 선택하면서 적응형 육각 탐색에 기반한 계층적 블록 정합을 수행함으로써 움직임 벡터 추정의 고속화를 실현함과 동시에 국부 최소화를 효과적으로 경감시킬 수 있는 블록 정합 알고리즘을 제안함에 그 목적이 있다. 우선, 초기 연속된 두 프레임에 대해 적응형 육각 탐색을 이용하여 움직임 벡터를 추정한 후 움직임 활동도를 산출한다. 이후, 움직임 활동도가 낮은 경우, 다음 프레임의 움직임 벡터를 추정 시 최하위 계층에서 적응형 육각 탐색을 수행하고, 움직임 활용도가 높은 경우 피라미드 계층 구조상의 최상위 계층에서부터 상하 계층들 간에 움직임 탐색 영역을 중복시키면서 움직임 벡터를 추정한다. 제안된 방법의 타당성과 보편성을 검증하기 위해 서로 다른 움직임 특성을 갖는 복수의 영상 시퀀스들을 대상으로 움직임 보상 화질과 수렴시간 측면에서 그 성능을 평가 분석하였다. 제안된 방법에 따르면, 고속 움직임 탐색이 가능한 적응형 육각 탐색의 장점을 유지하면서도 움직임 활동도가 높은 영상에서 야기되는 국부최소문제를 효과적으로 억제시키고 있음을 확인할 수 있었다.

• Journal of Welding and Joining
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• v.31 no.6
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• pp.37-43
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• 2013

This study targets to make clear the connection between MS (Martensite start) point and welding shrinkage. We approved that a Martensite-transformed weldment may not yield state under low MS point, but also admitted the limitation of numerical calculation by inherent strain approach or thermal strain approach. Therefore, new thermal strain formulae during cooling stages were made. As a thermal strain is obtained by integrating thermal extension coefficient, a constant of integration should be decided. In our suggested formulae, the origin was based on totally remained austenite, and added strain from volume changes in Martensite transformation was based on totally transformed ferrite. Through the suggested methodology, It is verified that an MS point under a critical temperature can let weld shrinkage relax and the critical value can be obtained. For supporting this process, 15 weld-consumables were made, were tested by fillet type and were measured. As a result, a positive correlation between MS point and level of weld-distortion was obtained, but it was rather weak.

• Journal of the Korean Society of Radiology
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• v.9 no.1
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• pp.39-45
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• 2015

$La_2W_3O_{12}:Eu^{3+}$ phosphors were prepared by solid state reaction method. The crystal structure was characterized by XRD pattern and ICSD card (78180). Luminescence properties of $La_2W_3O_{12}:Eu^{3+}$ are investigated by optical and laser-excitation spectroscopy in which emission and excitation spectra and time-resolved spectra are measured. The 1 mol % $Eu^{3+}$-doped $La_2W_3O_{12}$ phosphor exhibits broad excitation band peaking at 286 nm due to the ligand-to-metal charge transfer transition. The excitation lines due to the $^7F_0{\rightarrow}{^5D_4},{^5D_4},{^5L_6},{^5G_4},{^5D_3},{^5D_2}$ transitions of $Eu^{3+}$ are observed in the wavelength region 350-500 nm. The strong line emission is observed at 618 nm corresponding to the due to the $^5D_0{\rightarrow}^7F_2$ transition. The lifetime of 618 nm emission decreases with increasing temperature as 7 K ($114{\mu}s$), 100 K ($94{\mu}s$), 200 K ($10{\mu}s$) and 300 K ($0.5{\mu}s$).

• Restorative Dentistry and Endodontics
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• v.31 no.2
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• pp.125-132
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• 2006

This study was conducted to evaluate the insertion depth of Buchanan plugger after shaping by various Ni-Ti rotary files. It was conducted to determine which size of plugger are appropriate, when root canals are shaped with Ni-Ti rotary files and obturated by Continuous wave of condensation technique. Two type of eighty simulated resin blocks were used : J-shaped and straight shaped canal. The simulated canals were instrumented by ProTaper and ProFile. Buchanan pluggers were inserted into the canal, and then the image was recorded to scanner. The distance from the apex of the canal to the plugger tip was measured by image analysis program. Data were analyzed by one-way ANOVA followed by Scheffe's test. The results were as follows 1. In straight canal finished up to ProTaper F2 and F3 file, F and FM pluggers were inserted more than 5 mm short of working length. 2. In J-shaped canal finished up to ProTaper F2 file, F pluggers were inserted more than 5 mm short of working length. Finished up to ProTaper F3 file. F and FM pluggers were inserted more than 5 mm short of working length. 3. In straight and J-shaped canal finished up to ProFile .06/#20 and .06/#25, any of Buchanan plugger could not be inserted more than 5 mm short of working length. These results suggest that canals shaped by ProTaper could be obturated by Continuous wave of condensation technique with F and FM size Buchanan plugger.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.267-272
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• 1997

he scintillation detector having $BaF^2$ crystal with 3.6cm dia${\times}$2.0 cm thick was provided. The energy and timing characteristics were measured and compared with NaI(Tl) scintillation detectors, which widely used in unclear medicine. In order to measure the energy spectrum, the radioactive sources used were $^{22}Na,\;^{54}Mn,\;^{57}Co,\;^{137}Cs$ and the source to detector distance was 7cm. For the timing characteristic, NaI(Tl)(1" ${\times}$ 1")-$BaF^2$ and NaI(Tl)(3" ${\times}$ 3")-$BaF^2$ timing coincidence systems were prepared and the used source was $^{22}Na$ emitting 511keV annihilation photons. For the 511keV gamma-ray emitted from $^{22}Na$, It was revealed that the timing response of the $BaF^2$ detector was faster than NaI(Tl)(1" ${\times}$ 1") and NaI(Tl)(3" ${\times}$ 3") detector used in this experimental investigation. The energy characteristics of the $BaF^2$ detector had a good values for about 500keV energy range.

• Journal of the Korea Convergence Society
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• v.7 no.6
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• pp.133-139
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• 2016

This study was to evaluate the change of mineral loss of fTCP and CPP-ACP in artificial caries lesions using QLF-D to compare the remineralization effect of recently developed fTCP and CPP-ACP, which is widely used as a remineralization cream in current dental clinics. Bovine specimens used in this study formed the artificial caries lesion immersing in demineralization solution for 10 days and were divided randomly into the following two groups; Group 1- Tooth Mousse containing 10% CPP-ACP, Group 2- Clinpro Tooth Creme containing 950ppm NaF and fTCP. Two tooth paste were applied to the artificial caries lesion of specimens and they were immersed in artificial saliva for 1 week. Mineral loss of artificial caries lesion was evaluated by fluorescence loss (${\Delta}F$) values using QLF-D. QLF-D analysis showed that the ${\Delta}F$ and ${\Delta}Fmax$ value increased 2.65 and 6.63, respectively, in the Tooth Mousse group, and the mineral loss decreased statistically significantly(p<0.05). However, Clinpro Tooth Creme group had no statistically significant difference. ${\Delta}Fmax$ value of Tooth Mousse group was statistically significant difference compared to the Clinpro Tooth Creme. Therefore, the Tooth Mousse containing 10% CPP-ACP is more effective than Clinpro Tooth Creme containing fTCP in the treatment of remineralization of artificial caries lesions.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.4
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• pp.317-325
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• 2007

Purpose: Biological parameters can be quantified using dynamic PET data with compartment modeling and Nonlinear Least Square (NLS) estimation. However, the generation of parametric images using the NLS is not appropriate because of the initial value problem and excessive computation time. In irreversible model, Patlak graphical analysis (PGA) has been commonly used as an alternative to the NLS method. In PGA, however, the start time ($t^*$, time where linear phase starts) has to be determined. In this study, we suggest a new Multiple Linear Analysis for irreversible radiotracer (MLAIR) to estimate fluoride bone influx rate (Ki). Methods: $[^{18}F]Fluoride$ dynamic PET scans was acquired for 60 min in three normal mini-pigs. The plasma input curve was derived using blood sampling from the femoral artery. Tissue time-activity curves were measured by drawing region of interests (ROls) on the femur head, vertebra, and muscle. Parametric images of Ki were generated using MLAIR and PGA methods. Result: In ROI analysis, estimated Ki values using MLAIR and PGA method was slightly higher than those of NLS, but the results of MLAIR and PGA were equivalent. Patlak slopes (Ki) were changed with different $t^*$ in low uptake region. Compared with PGA, the quality of parametric image was considerably improved using new method. Conclusion: The results showed that the MLAIR was efficient and robust method for the generation of Ki parametric image from $[^{18}F]Fluoride$ PET. It will be also a good alternative to PGA for the radiotracers with irreversible three compartment model.

• Applied Biological Chemistry
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• v.36 no.4
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• pp.310-314
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• 1993

High performance liquid chromatographic method using a TSK-gel amide 80 column and isocratic elution with acetonitrile-water (63 :35 ;v/v) mixture was used for the separation and the quantitation of fructo (GF2-GF7)- and inulo-oligosaccharides (F2-F4). Retention time of each standard carbohydrate was highly reproducible. Standardization curves obtained by plotting the peak areas against the amounts of each carbohydrate showed very high coefficient of determination$({\ge}0.9884)$ and similar slopes, and a wide range of y-intercepts. Our results suggest the use of each Pure oligosaccharide for its own standardization curve instead of using a certain carbohydrate as an internal standard.