• Title/Summary/Keyword: Contrast materials

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A Study on the Effective Utilization of Intensifying Screens in the Region of Diagnostic Radiology (진단방사선 영역에서 증감지의 유효이용에 관한 연구)

  • Kim, Young-Keun;Lee, Kyung-Sup
    • Journal of radiological science and technology
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    • v.22 no.1
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    • pp.43-47
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    • 1999
  • In order to obtain effective utilization of intensifying screens[$CaWO_4(W),\;Gd_2O_2S:Tb(Gd)$, BaFCl : Eu(Ba)] over the diagnostic radiology range, we calculated absorption coefficient (${\mu}$), absorption efficiency (${\eta}_{\alpha}$) and absorbed energy ratio(R) and analyzed effects of these properties on X-ray image, finally concluded as below. Regardless of presence of contrast media, absorption coefficient of Gd the highest and decreased with increase of thickness and kVp. Absorption efficiency related with absorbance of fluorescent materials showed the highest value for the Gd, and discontinuous points exhibited at around $80{\sim}90\;kVp$ and $90{\sim}100kVp$ for the Ba and the Gd, respectively. Furthermore, the absorbed energy ratio(R) correspond to contrast of reflection showed the largest value for the W in the absence of contrast media, and for the Gd in the case of the existence of it, and the ratio was decreased with increasing of incident energy. Owing to these properties, we assumed that it was more preferable to use rare earth type intensifying screen for the radiography using in the C.M.(I, Ba), while in the general radiography, $CaWO_4$ intensifying screen was applicable.

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The Clothing Image according to Coloration, Tone, and Interval of Checked Pattern in Color Contrast (색상대비 체크무늬의 배색, 톤, 간격에 따른 의복이미지)

  • Jeong, Su-Jin;Choi, Su-Koung
    • Fashion & Textile Research Journal
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    • v.13 no.2
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    • pp.147-154
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    • 2011
  • The purpose of this study was to investigate the clothing image according to coloration, tone, and interval of checked pattern in color contrast. The experimental materials developed for this study were a set of stimulus and response scales. The stimuli were 24 color pictures, in which coloration(RB: Red+Blue, YP: Yellow+Purple), tone(light, dull, dark), and interval(0.5 cm, 1.5 cm, 3.5 cm, 5.5 cm) were manipulated. The 7-point scale was used for evaluation of clothing image. Data were obtained from 240 female college students living in Seoul, Gwangju, Jinju, and Masan on May 2010. For data analysis, ANOVA and Duncan-test were used by using SPSS program. Results of this study were as follows.; Clothing image according to coloration, tone, and interval of checked pattern consisted of five dimensions of attractiveness, freshness, appeal, modesty, and activity. Coloration showed an independent effect on attractiveness and appeal. Tone showed an independent effect on freshness, appeal, and modesty. Interval showed an independent effect on freshness. Also, interaction effects of coloration and tone on appeal were found. Interaction effects of coloration and interval on modesty were found.

High performance guest-host liquid crystal display mode using the charged particles (대전입자를 이용한 고성능 Guest-Host 액정 디스플레이 모드)

  • Mun, Byung-June;Youn, Sung-Ho;Lee, Gi-Dong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.7
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    • pp.1512-1517
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    • 2012
  • In this paper, we proposed the novel hybrid guest-host liquid crystal display using the negative charged black particles in order to improve the low contrast ratio. We designed patterned electrode in order to switch the charged particle to the opposite electrode and improved the electro-optical characteristics by optimize the mixture of guest materials. In Comparison with the Heilmeier Guest-Host mode, proposed hybrid guest-host structure showed 80% reduction of transmittance in dark state, and the performance was examined by comparing contrast ratio.

Scan Time Analysis Using 4D Phase-Contrast MRI According to Scan Parameter: A Phantom Study (스캔 인자에 따른 4D 위상 대조 자기공명영상을 이용한 스캔 시간 분석: 팬텀 연구)

  • Park, Jieun;Kim, Junghun;Hwang, Moonjung;Lee, Jongmin
    • Journal of Biomedical Engineering Research
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    • v.41 no.5
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    • pp.179-184
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    • 2020
  • Purpose: The purpose of this study was to evaluate the effect according to the NEX, VENC, targeted cardiac phases on the velocity measurement of 4D phase-contrast MRI. Materials and Methods: The abdominal aortic phantom was made to experiment. The working fluid was mixed with water and glycerin to mimic the density and viscosity of human blood. The inlet velocity was Reynolds number 2000. The experimental conditions were NEX 1 and 4, VENC 102 cm/s and 200 cm/s, and 10 and 15 targeted cardiac phases, respectively. The average flow rate, average velocity, maximum velocity, and cross-section area were measured. Results: As a result of the case-by-case comparison, the error rate was less than 5%. There was no significant difference (p > 0.05). Conclusion: It is expected that this result will be useful for acquiring blood flow information in clinical practice.

The Study of the Printability on the Phenol Free Heat-Set Web Inks(II) - Analysis by the trial printing test - (Phenol Free Heat-Set 윤전 잉크의 인쇄적성에 관한 연구(제2보) - 실 인쇄 실험에 의한 분석 -)

  • Ha, Young-Baeck;Oh, Sung-Sang;Lee, Won-Jae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.44 no.3
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    • pp.41-48
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    • 2012
  • Materials used for the inks in the printing industry is an important material following the paper. The composition of the ink is pigment and organic solvents. However, Ink is used in a variety of chemicals, they are classified as non-green. Therefore, rosin-modified phenolics manufactured by the reaction of phenol and formaldehyde can take the place of eco-phenol free resin and by experiment density, gloss, trapping, contrast and dot gain of printing has been studied as printability. The result of study can support that the properties of printing using eco-phenol free resin such as density, gloss, contrast and trapping is similar to existing ink. In the part of dot gain, the result is excellent. So we were thought to be able to improve some characteristics such as dispersion of black ink, that will be possible for the field applicability.

Electrochromism of Various Conducting Polymers with Enhanced Functionality (기능성을 향상시킨 다양한 전도성 고분자의 전기 변색 현상)

  • Ko Heung-Cho;Moon Bong-Jin;Lee Hoo-Sung
    • Polymer(Korea)
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    • v.30 no.5
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    • pp.367-372
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    • 2006
  • Electrochromic materials based on conducting polymers with pendant chromophores as well as their electrochromic properties are described. The conducting polymers described aye polypyrrole, polythiophene, poly(3,4-ethylenedioxythiophene), poly (cyclopentadithiophene), and poly (1,4-bis [2- (3,4-ethylenedioxy) thienyl] benzene). The chromophores described are viologen and perylenetetra-carboxylic diimide. When the wavelength ranges of absorption of the conducting polymer and the chromophore aye not overlapping, multiple electrochromism was achieved. When the wavelength ranges are largely overlapping, higher contrast was achieved. An easy method for prediction of the film thickness for maximum contrast of a given electrochromic material is also described.

Dynamic Contrast-Enhanced MRI of the Prostate: Can Auto-Generated Wash-in Color Map Be Useful in Detecting Focal Lesion Enhancement?

  • Yoon, Ji Min;Choi, Moon Hyung;Lee, Young Joon;Jung, Seung Eun
    • Investigative Magnetic Resonance Imaging
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    • v.23 no.3
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    • pp.220-227
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    • 2019
  • Purpose: To evaluate the usefulness of wash-in color map in detecting early enhancement of prostate focal lesion compared to whole dynamic contrast-enhanced MRI (DEC MRI) images. Materials and Methods: This study engaged 50 prostate cancer patients who underwent multiparametric MRI and radical prostatectomy as subjects. An expert [R1] and a trainee [R2] independently evaluated early enhancement and recorded the time needed to review 1) a wash-in color map and 2) whole DCE MRI images. Results: The review of whole DCE images by R1 showed fair agreement with color map by R1, whole images by R2, and color map by R2 (weighted kappa values = 0.59, 0.44, and 0.58, respectively). Both readers took a significantly shorter time to review the color maps as compared to whole images (P < 0.001). Conclusion: A trainee could achieve better agreement with an expert when using wash-in color maps than when using whole DCE MRI images. Also, color maps took a significantly shorter evaluation time than whole images.

Perceived Dark Rim Artifact in First-Pass Myocardial Perfusion Magnetic Resonance Imaging Due to Visual Illusion

  • Taehoon Shin;Krishna S. Nayak
    • Korean Journal of Radiology
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    • v.21 no.4
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    • pp.462-470
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    • 2020
  • Objective: To demonstrate that human visual illusion can contribute to sub-endocardial dark rim artifact in contrast-enhanced myocardial perfusion magnetic resonance images. Materials and Methods: Numerical phantoms were generated to simulate the first-passage of contrast agent in the heart, and rendered in conventional gray scale as well as in color scale with reduced luminance variation. Cardiac perfusion images were acquired from two healthy volunteers, and were displayed by the same gray and color scales used in the numerical study. Before and after k-space windowing, the left ventricle (LV)-myocardium boarders were analyzed visually and quantitatively through intensity profiles perpendicular the boarders. Results: k-space windowing yielded monotonically decreasing signal intensity near the LV-myocardium boarder in the phantom images, as confirmed by negative finite difference values near the board ranging -1.07 to -0.14. However, the dark band still appears, which is perceived by visual illusion. Dark rim is perceived in the in-vivo images after k-space windowing that removed the quantitative signal dip, suggesting that the perceived dark rim is a visual illusion. The perceived dark rim is stronger at peak LV enhancement than the peak myocardial enhancement, due to the larger intensity difference between LV and myocardium. In both numerical phantom and in-vivo images, the illusory dark band is not visible in the color map due to reduced luminance variation. Conclusion: Visual illusion is another potential cause of dark rim artifact in contrast-enhanced myocardial perfusion MRI as demonstrated by illusory rim perceived in the absence of quantitative intensity undershoot.

A flexible OTFT-OLED display using solution-processed organic dielectrics

  • Hirai, Nobukazu;Katsuhara, Mao;Yagi, Iwao;Yasuda, Ryoichi;Ushikura, Shin-Ich;Noda, Makoto;Moriwaki, Toshiki;Imaoka, Ayaka;Yoneya, Nobuhide;Yumoto, Akira;Nomoto, Kazumasa;Urabe, Tetsuo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.131-134
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    • 2009
  • We have developed a flexible OTFT backplane in which all the dielectrics are formed by solutionprocess in order to achieve low-cost and highthroughput manufacturing. The backplane successfully drives a flexible AM-OLED display with peak brightness of > 200 nit and the contrast ratio of > 1000:1 with great mechanical flexibility.

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Setting Behavior and Drug Release from Brushite Bone Cement prepared with Granulated Hydroxyapatite and β-Tricalcium Phosphate

  • Son, Yeong-Jun;Lee, In-Cheol;Jo, Hyun-Ho;Chung, Tai-Joo;Oh, Kyung-Sik
    • Journal of the Korean Ceramic Society
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    • v.56 no.1
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    • pp.56-64
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    • 2019
  • Calcium phosphate bone cement was prepared to contain antibiotics for release after setting using granulated ${\beta}$-tricalcium phosphate (${\beta}$-TCP) and hydroxyapatite (HA). Gentamicin sulfate (GS) solution was infiltrated within the interconnected pores of the granule to avoid affecting the setting reaction and for protection of GS during the setting. Consequently, the setting time and the temperature increase were not affected, regardless of the loading of GS. The release of the GS from the cement was estimated by measuring the concentration at regular intervals from the cement dipped solution. The ${\beta}$-TCP granule loaded with GS exhibited the saturation of accumulative concentration at 16 h. In contrast, the HA granule with GS exhibited steady increase in accumulative concentration of over $10{\mu}g/ml$ at 144 h. Thus, the granulated cement could release the GS greater than the minimum inhibitory concentration of staphylococcus during the prescription peroid of the oral antibiotics.