• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.436-438
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• 2002

As the use of virtual simulation expands, digitally reconstructed radiographs (DRRs), which mimic conventional simulation films, play an increasingly important role as reference images in the verification of treatment fields. The purpose of our study is to develop an algorithm for computation of digitally reconstructed radiographs based on Monte Carlo simulation that take into account almost all possible physical processes by which photons interact with matter. The Monte Carlo simulation based DRRs have the following features. 1) Account has been taken of almost all possible physical processes of interaction of photons with matter, including a detector (film) response. In principle, this is equivalent to X-ray radiography. 2) Arbitrary photon energies (from diagnostic to therapeutic) can be used to produce DRRs. One can even use electrons as the source. 3) It is easy to produce a double exposure, which mimics the double exposure portal image and may have superior visual appeal for treatment field verification, with weighting within the treatment field.

• 대한한방소아과학회지
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• 제20권3호
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• pp.23-32
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• 2006

Objectives : The object of this study was to evaluate the effect of oriental medical treatment to the growth of children using bone age as measurer. Methods : This clinical study has been carried out with 32 cases(male 15, female 17 of children) aging from 7 to 15 years old, who visited to the Department of Pediatrics growth clinic, ○○ medical center from January 2004 to August 2006 and were treated for more than 12 months. Their height, body weight, body mass index(BMI) and bone age were estimated at two points: Before and after oriental medical treatment was applied. Bone age is measured by X-ray image of growth plate in inferior radiocarpal joint. Results : Bone age correlated with choronological age, height, weight. Difference between bone and choronological age was correlated with percentile of height and weight. The mean growth of children showed 4.03 percentile upwardly(p=.046), and difference between bone and choronological age was reduced from $0.23{\pm}1.62$ to $-0.026{\pm}1.64(p=.040)$ after treatment. Conclusions : This study shows that oriental medical treatment helped growth of children using bone age as measurer.

• 한국재료학회지
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• 제27권10호
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• pp.530-533
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• 2017

ZnO micro/nanocrystals with different morphologies were synthesized by thermal evaporation of various zinc source materials in an air atmosphere. Zinc acetate, zinc carbonate and zinc iodide were used as the source materials. No catalysts or substrates were used in the synthesis of the ZnO crystals. The scanning electron microscope(SEM) image showed that the morphology of ZnO crystals was strongly dependent on the source materials, which suggests that source material is one of the key factors in controlling the morphology of the obtained ZnO crystals. Tetrapods, nanogranular shaped crystals, spherical particles and crayon-shaped crystals were obtained using different source materials. The X-ray diffraction(XRD) pattern revealed that the all the ZnO crystals had hexagonal wurtzite crystalline structures. An ultraviolet emission was observed in the cathodoluminescence spectrum of the ZnO crystals prepared via thermal evaporation of Zn powder. However, a strong green emission centered at around 500 nm was observed in the cathodoluminescence spectra of the ZnO crystals prepared using zinc salts as the source materials.

• 한국정밀공학회지
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• 제13권6호
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• pp.34-44
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• 1996

In order to examine the accuracy of the intensity method, the fiber orientation-angle distribution of fiber-reinforced polymeric composites is measured using image processing. The fiber orientation function is calculated from the fiber orientation measured by the soft X-ray photograph. Theoretical and experimental results of fiber orientation function are compared for the composites with different fiber contents and fiber orientations. The intensity method is used for the experimental investigation and the measured fiber orientation function is compared to the calculated one. The relations between the measured and the simulated fiber orientation functions $J{\small{M}}$ and $J{\small{S}}$ respectively are identified. For the fiber length of 1.000mm and 2.000mm, it shows that $J{\small{M}}=0.83J{\small{M}}$. However. in general. the value of $J{\small{M}}$ decreases as the fiber length increases. For GFRP composites the relations between $J{\small{M}}$ and theoretical value J show that $J{\small{M}}$=0.73J for short fiber and $J{\small{M}}$=0.81J for long fiber.

• 한국분말재료학회지
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• 제9권2호
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• pp.89-95
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• 2002

Spherical fine powders of tungsten oxide powders were prepared by the emulsion evaporation method. The characteristics of the powders prepared were examined by means of TGA, X-ray diffraction, SEM and image analysis. The emulsions were prepared by fast mixing of aqueous phase containing tugsten and the organic phase which composed of kerosene, surfactant, and paraffin oil. Precursors were made by evaporating the emulsionin the kerosene bath at $160^{\circ}C$, and then calcined at $650^{\circ}C$ in order to produce tungsten oxide powders. The average particle size of the tungsten oxide powders was $0.5\mutextrm{m}$ and their shapes were spherical at the both case of w/o and o/w type emulsions. As the HLB value of the surfactant increased and the concentration of tungsten ions decreased the mean particle siqe of tungsten oxide powders decreased whereas agglomerationsize increased. The optimum concentration of Span 80 was 8 percent by volume, and the optimum stirring speed in the emulsion formation was 5000 rpm in order to obtain fine and well dispersed $WO_3$ powders.

• 대한의용생체공학회:의공학회지
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• 제21권2호
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• pp.119-127
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• 2000

금속판/형과스크린 계측기와 CCD 카메라를 이용한 방사선영상장치가 현재 전자포탈영상에 널리 쓰이고 있다. 이 장치의 효율적인 영상획득을 위해 계측효율이 좋고, 공간분해능력이 뛰어난 금속판/ 형과스크린 계측기의 두께를 최적화할 필요가 있었다. 이 논문에서는 금속판과 형광스크린의 두께가 계측효율과 공간분해능에 미치는 영향이 연구되었다. 이 결과는 치료 엑스선 영상장치에 쓰일 수 있는 금속판/형과스크린 계측기의 최적화된 두께를 결정하는데 쓰일 수 있다. 몬테칼로 방법을 이용하여 계산한6 MV 선형가속기에서 발생되는 엑시선의 에너지 스펙트럼을 바탕으로, 여러 가지 두께의 금속판/형광스크린에 대하여 계측효율과 공간분해능을 계산하였고, 이를 실험을 통해 검증하였다. 계측효율은 입사된 엑스선의 에너지가 형광스크린에 흡수된 비율로 계산되며, 공간분해능은 흡수된 에너지의 공간 분포를 통해 계산되었다. 계측효율은 금속판의 두께에 의해, 공간분해능은 형광스크린의 두께에 의해 결정될 수 있음을 본 연구를 통해 확인할 수 있었고, 이로써 특정이용에 관련된 금속판/형광스크린의 두께에 대한 서로 보상 (trade-off) 관계에 있음을 계산과 측정결과를 통해 확인할 수 있었고, 이로써 특정이용에 관련된 금속판/형광스크린 계측기의 최적화된 두께를 산출할 수 있게 되었다. 계산을 바탕으로 CCD를 이용한 전자포탈영상장치의 시작품을 설계 및 제작하였고 팬텀을 이용하여 영상을 얻었다. 단일 프레임 영상은 노이즈가 많으나, 프레임 평균 방법을 이용하여 영상의 질을 향상시킬 수 있었다.

• Imaging Science in Dentistry
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• 제38권4호
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• pp.209-213
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• 2008

Purpose : To evaluate the relative diagnostic accuracy of panoramic radiography and Water's projection in maxillary sinus inflammatory diseases by comparing the radiodensities of the images with those of CT. Materials and Methods : Panoramic radiographs, Waters' projection, and CT images from 55 subjects (11O sinuses) were included in this retrospective study. The radiodensity of each maxillary sinus in panoramic radiography was recorded separately as upper and lower divided horizontally by hard palate. In Waters' projection, the overall sinus radiodensity was recorded. The CT images were considered as gold standard. Results : In panoramic radiography, 83 sinuses had same upper and lower radiodensity and 72 of these were consistent with those of CT, 26 sinuses had different upper and lower radiodensity and 15 of these, upper radiodensity was consistent with CT, the remaining 11, lower radiodensity was consistent with CT. One sinus had upper radiolucency with lower radiopacity and both were consistent with those of CT. Altogether 73 (66.4%) among 110 sinuses in panoramic radiography showed full agreement with CT, 26 (23.6%) showed partial agreement with CT. 9 sinuses had no lower image under the hard palate in panoramic radiography due to the smaller size of sinus. In Waters' projection, the radiodensity of 105 sinuses (95.5%) were consistent with that of CT. Conclusion : The panoramic radiography showed 90.0% of the sinus conditions fully or partially which may appear less accurate than that of Water's view (95.5%) but with more detailed information of the inferior part of sinuses. (Korean J Oral Maxillofac Radiol 2008; 38 : 209-13)

• Transactions on Electrical and Electronic Materials
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• 제8권6호
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• pp.250-254
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• 2007

Applying the moving photo-carrier grating(MPG) technique and time-of-flight(TOF) measurements, we studied the transport properties of stabilized amorphous selenium typical of the material used in direct conversion X-ray imaging devices. For MPG measurement, we obtained electron and hole mobility and the recombination lifetime of $\alpha-Se$ films with arsenic(As) additions. We found an apparent increase in hole drift mobility and recombination lifetime, especially when 0.3 % As was added into $\alpha-Se$ film, whereas electron mobility decreased with the addition of As due to the defect density. For TOF measurement, a laser beam with pulse duration of 5 ns and wavelength of 350 nm was illuminated on the surface of $\alpha-Se$ with a thickness of 400 ${\mu}m$. The measured hole and electron transit times were about 8.73 ${\mu}s$ and 229.17 ${\mu}s$, respectively.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.575-580
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• 2014

We uniformly coated Eu(III)- and Tb(III)-doped yttrium oxide onto the surface of $SiO_2$ spheres and then characterized them by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction crystallography and UV-Visible absorption. 2D and 3D photoluminescence image map profiles were reported for the core-shell type structure. Red emission peaks of Eu(III) were observed between 580 to 730 nm and assigned to $^5D_0{\rightarrow}^7F_J$ (J = 0 - 4) transitions. The green emission peaks of Tb(III) between 450 and 650 nm were attributed to the $^5D_4{\rightarrow}^7F_J$ (J = 6, 5, 4, 3) transitions. For annealed samples, Eu(III) ions were embedded at a $C_2$ symmetry site in $Y_2O_3$, which was accompanied by an increase in luminescence intensity and redness, while Tb(III) was changed to Tb(IV), which resulted in no green emission.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.881-882
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• 2006

According as society looks graying trend gradually, more shaped system that can achieve measuring health-state of old people more harmoniously construction required in field of old people's welfare and medical treatment. Health-state is measured by two methods of contact and non-contact. The first, for example measurement of blood pressure or electrocardiogram, requires that measuring equipments are attached on human body but the second, for example X-Ray or MRI, is not. But both of methods are have some of defect, for example attaching equipments, needing of the special equipments or the necessary time, etc. Therefore desirable method of monitoring system must have minimum interrupt about daily life. This study suggest the system that can monitor the user, especially old people's outward aging and health-state by use the PAN TILTER and CCD camera.