• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1120-1124
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• 2004

Recently, Plasma Display Panel(PDP) has been in the spotlight as one of the next generation flat-panel-display device. However, it has several drawbacks like the low contrast ratio and the low luminance. In this study, a new address waveform is suggested to improve the priming effect and contrast ratio at the address period in the Address Display period Separated(ADS) method. We modified waveform, instead of a conventional waveform, to an address period, for operating on the Plasma Display Panels, which used the conventional gas [He-Ne-Xe〕. When the ramp pulse is added to the address period at the sustain electrode, it is improved on the priming effect and contrast ratio.

• Journal of radiological science and technology
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• v.23 no.1
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• pp.91-96
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• 2000

This work was on the reduction of exposure dose and contrast improvement by Use of Heavy Elements Filter From the result of experimental evaluation, it was found that the beam harding of X-ray was not showed in Ho and Gd, heavy elements filters, contrast to Cu and Al filters In which the harding showed. And the ratio of transit dose to surface dose and the load of X-ray tube increase in order of Al, Cu, Gd and Ho, respectively. The contrast of X-ray images using the intensifying screen and the input phosphor showed the higher value in order of Cu, Al, Gd and Ho. Therefore, in the case of using contrast media and phosphor in region of diagnostic radiology, X-ray image quality depends primarily on kVp and heavy elements filters.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.656-659
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• 2006

MD (DLP, LCoS) Projection TV is appropriate for large screen display with high definition at a relatively low price and thus, has been popular in the digital TV market. In order to realize high resolutions in the DLP projection TV, we successfully developed the Pixel Enhancement Actuator. Furthermore, it is also required that the contrast ratio of projected video signals onto a large screen should be improved. Therefore, we propose a contrast enhancer which adjusts the amount of projected lights by a dynamic aperture and a attached position sensor.

• Journal of the Optical Society of Korea
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• v.18 no.2
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• pp.184-187
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• 2014

This study examined the effects of particle size on the light scattering of a nano-sized color filter pigment used to obtain a range of colors in liquid crystal displays. The contrast ratio is one of the most important characteristics of liquid crystal displays. When a color filter is located between two crossed polarizers, the size of the pigment can give rise to a decrease in the contrast ratio due to Rayleigh scattering by the nanoparticles in the filter. The size effect of the color filter pigment on the contrast ratio was investigated in terms of the depolarization parameter. As an experimental result, the depolarization parameter increased with decreasing pigment size. Therefore, a smaller pigment size can reduce light leakage caused by light scattering in the color filter between two crossed polarizers. The depolarization function was also proposed as a useful function for predicting the decrease in the contrast ratio of the color filter.

• MALSORI
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• no.60
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• pp.1-11
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• 2006

This paper investigated AV benefit of Korean and Japanese EFL learners' perception of the liquid contrast in English. In a perception experiment, the two English consonants /l/ and /r/ were embedded in initial and medial position in nonsense words in the context of the vowels /i, a, u/. Singletons and clusters were included in the speech material. Audio and video recordings were made using a total of 108 items. The items were presented to Korean and Japanese learners of English in three conditions: audio-alone (A), visual-alone (V) and audio-visual presentation (AV). The results showed that there was no evidence of AV benefit for the perception of the /l/-/r/ contrast for either Korean or Japanese learners of English. The results suggest that increasing auditory proficiency in identifying a non-native contrast is linked with an increasing proficiency in using visual cues to the contrast.

• Investigative Magnetic Resonance Imaging
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• v.25 no.4
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• pp.209-217
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• 2021

Magnetic resonance angiography (MRA) plays an important role in accurate diagnosis and appropriate treatment planning for patients with arterial disease. Contrast-enhanced (CE) MRA is fast and robust, offering hemodynamic information of arterial flow, but involves the risk of a side effect called nephrogenic systemic fibrosis. Various non-contrast-enhanced (NCE) MRA techniques have been developed by utilizing the fact that arterial blood is moving fast compared to background tissues. NCE MRA is completely free of any safety issues, but has different drawbacks for various approaches. This review article describes basic principles of CE and NCE MRA techniques with a focus on how to generate angiographic image contrast from a pulse sequence perspective. Advantages, pitfalls, and key applications are also discussed for each MRA method.

• Current Optics and Photonics
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• v.7 no.1
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• pp.65-72
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• 2023

The motion of organelles inside a cell is an important intrinsic indicator for assessing cell physiology and tissue viability. Dynamic contrast full-field optical coherence tomography (D-FFOCT) is a promising imaging technology that can visualize intracellular movements using the variance of temporal interference signals caused by biological motions. However, double-path interferometry in D-FFOCT can be highly vulnerable to surrounding noise, which may cause turbulence in the interference signals, contaminating the sample dynamics. Therefore, we propose a method for stabilized D-FFOCT imaging in noisy environments by using common-path interferometry in D-FFOCT. A comparative study shows that D-FFOCT with the proposed method achieves stable dynamic contrast imaging of a scattering phantom in motion that is over tenfold more noise-insensitive compared to the conventional one, and thus this imaging capability can provide cleaner motion contrast images. With the proposed approach, the intracellular dynamics of biological samples are imaged and monitored.

• Journal of Veterinary Clinics
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• v.40 no.5
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• pp.375-381
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• 2023

A large abdominal mass was incidentally found in a 13-year-old mixed-breed dog and was confirmed to be a cecal gastrointestinal stromal tumor (GIST). Contrast-enhanced ultrasound and post-contrast computed tomography (CT) showed mild contrast enhancement of the mass, indicating low blood flow. The tumor origin was determined to be the cecum by identifying the vessels supplying the mass on post-contrast CT. The exophytic growth of the tumor left the cecal lumen intact without obstruction. This report described the CEUS and CT perfusion of the cecal GIST and perfusion evaluation can help diagnose and characterize GISTs in dogs.

• The Korean Journal of Pain
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• v.28 no.4
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• pp.280-283
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• 2015

Caudal epidural injection is a common intervention in patients with low back pain and sciatica. Even though the complications of fluoroscopically directed epidural injections are less frequent than in blind epidural injections, complications due to contrast media can occur. We report a case of anaphylactic shock immediately after injection of an intravenous nonionic contrast medium (iohexol) during the caudal epidural injection for low back pain and sciatica in a patient without a previous allergic history to ionic contrast media (ioxitalamate). Five minutes after the dye was injected, the patient began to experience dizziness, and the systolic blood pressure dropped to 60 mmHg. Subsequently, the patient exhibited a mild drowsy mental state. About 30 minutes after the subcutaneous injection of 0.2 mg epinephrine, the systolic blood pressure increased to 90 mmHg. The patient recovered without any sequela. Life-threatening complications after injection of intravenous contrast medium require immediate treatment.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.59-63
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• 2001

Using the rotation of two polarizer plate and the area of transmittance In the visual light region measured by spectrophotometer, we obtained the luminance to measure the Contrast Sensitivity, and calculated the values of $L_{min}$ and ${\theta}_{min}$ after fixed the average contrast, $L_{max}$ and ${\theta}_{max}$ values from the values of two contrasts. Then, when it was fixed by $L_{max}=4000(T%nm)$ and ${\theta}_{max}=44.1^{\circ}$, $L_{min}$ and ${\theta}_{min}$ values were respectively given by 1333, 2666, 3920(T%nm) and 56.6, 54.3, $45^{\circ}$ in Cs values of 2.5, 100.