• Title, Summary, Keyword: 신호강도

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Measurements of spectrum distribution and signal intensity of NO particles according to reactor type using atmospheric AC discharga I (대기압 교류방전을 이용한 NO입자의 방전조건의 변화에 따른 분광 스펙트럼 분포와 신호강도 측정 I)

  • Jun, Yong-Woo;Jung, Chul-Woo;Yang, Jung-Hyun;Park, Won-Zoo;Lee, Kwang-Sik
    • Proceedings of the KIEE Conference
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    • pp.1779-1781
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    • 2002
  • 본 연구에서는 대기압 교류방전시 비열플라즈마를 이용하였을 때 NO입자의 분광스펙트럼과 전극재질과 전극두께에 따른 신호강도를 측정하였다. 분광기를 이용하여 측정된 NO입자의 분광스펙트럼 분포를 바탕으로 측정된 파장대역 중에서 비교적 신호강도가 큰 파장대역인 226[nm], 236[nm], 247[nm], 259[nm]에서 전극의 재질을 스테인레스, 구리, 알루미늄으로 변화시켰을 때의 신호강도와 전극의 두께를 4[mm], 5[mm], 6[mm]로 변화시켰을 때의 신호강도를 분광기(Monochromator)를 이용하여 측정하였다. 또한, 측정대상 중 전극재질은 구리일때가 가장 신호강도가 높음을 확인할 수 있었으며 전극두께는 갭 간격이 작을수록 신호강도가 강한 것을 확인함으로써 NO입자의 방전 메카니즘을 보다 명확하게 규명하고 또한 방전 리액터 제작에도 좋은 자료를 제공할 수 있을 것으로 생각된다.

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Comparative Study of a Multi-Channel Coils of Magnetic Resonance Imaging(MRI) Signal Intensities under Identical Parameters (동일한 조건의 자기공명검사에서 코일의 채널수 변화에 따른 신호강도의 평가)

  • Son, Soon-Yong
    • The Journal of the Korea Contents Association
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    • v.19 no.6
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    • pp.418-423
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    • 2019
  • The purpose of this study was to determine how the different number of channels of coils were related in the perceived signal intensity under identical parameters and area. Dedicated knee phantoms were scanned consecutively using both of the 16-channel and 8-channel knee coils. The T1 weighted and T2 weighted sequences were acquired using both coils to compare the signal intensities according to the number of channels. As a result, the 16-channel knee coils outperformed the 8-channel knee coils and the signal intensity was significantly increased in both of the T1 and T2 weighted images with the 16-channel coil. In conclusion, it is considered that better signal intensities and more clinical utility can be provided, when coils with more number of channels are used rather than using the coils with smaller number of channels.

Diffusion-Weighted MR Imaging of Various Intracranial Diseases : Clinical Utility (다양한 두개강내 질환의 확산강조 자기공명영상 : 임상적 유용성)

  • 김영준
    • Investigative Magnetic Resonance Imaging
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    • v.2 no.1
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    • pp.104-112
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    • 1998
  • Purpose : To evaluate the clinical utility of diffusion-weighted imaging by analyzing the signal intersity of lesions in patients with various intracranial diseases. Materials and Methods : difusion-weighted MR imaging was prospectively perormed in randomly selected 70 patients with various intracranial idseases. They consisted of 20 patients with acute infarct, 21 patients with chronic infarct of small vessel disease, 14 patients with primary intracranial tumor, three patients with brain metastasis, five patient with brain abscess, five patients with brain abscess, five patients with cerebral hemorrhage, one patient with neurocysticercosis, and one patient with epidermoid cyst. the diffusion-weighted images were obtained immediately after routine T2-weighted imaging on a 1.5T MR unit using single shot spin echo EPI technique with 6500 ms TR, 107ms TE, $128{\times}128$ matrix, 1 number of excitation, $24{\times}24$ field of view, 5-7 mm slice thickness, 2-3 mm inter-slice gap. The diffusion-gradients (b value of ($1000s{\;}/{\;}textrm{mm}^2$)) were applied along three directions(x, y, z). On visual inspection of diffusion-weighted images, the signal intersity of lesions was arbitrarily graded as one of 5 grades. In quantitative assessment, we measured the signal intensity of all the lesions and the contralateral corresponding normal area using round region of interest(ROI), and then calculated the signal intensity ratio of the lesion to the normal brain parenchyma. Results : On visual inspection, markedly hyperintense signals were seen in all cases of acute infarct, brain abscess, epidermoid cyst, and neurocysticercosis in degenerating stage. In all cases of cerebral hematoma, the very high signal internsity was intermingled with low signal intensity. focal very high signal intersity was also seen in a solid portion of the tumor in a patient. the mean signal intensity ratios of all those lesions to the normal brain parenchyma were above 2.5. Gliosis, solid component of brain tumor, brain metastasis, and vasogenic dedma appeared isointense to the normal brain parenchyma in 71%, 64%, 100%, and 67%, respectively ; the mean signal intensity ratios of those lesions to the normal brain parenchyma ranged 1.15 to 1.28 and there was no significant difference among these(p>0.1). Cystic cerebromalacia and necrotic or cystic portions in tumor were markedly or slightly hypointense, and the mean signal intensity ratios were 0.45 and 0.42, respectively. Conclusion : Very high signal intensity of acute infarct, brain abscess, epidermoid cyst, and cystic neurocysticercosis in degenerating stage on diffusion-weighted images may be helpful in differentiating from other diseases that are hypointense or isointense to the normal brain parenchyma. It may be especially useful differentiation of brain abscess from brain tumor with necrotic or cystic portion.

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Signal Intensity Changes according to Coil Position Changes in MRI using 6 Channel SENSE Cardiac Array Coils (6채널 SENSE Cardiac Array 코일을 이용한 검사 시 코일의 위치 변화에 따른 신호강도)

  • Choi, Kwan-Woo;Son, Soon-Yong;Yoo, Beong-Gyu
    • Journal of the Korean Society of Radiology
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    • v.12 no.5
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    • pp.699-706
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    • 2018
  • In this study, we measured signal intensities according to array coil position changes to provide reference data of coil directions and the distances as it deters image quality unless the coils are aligned properly. The multi-purpose MRI phantom was placed in body array coils, and it was moved to the top, bottom, left, and right directions by 2 cm from the center to 10 cm. After obtaining images, signal intensities were measured and compared. The results of this study were as follows: Except for the upward direction, the signal intensities of the reference signal was not significantly different from that of the reference signal intensity within 2cm in both T1 and T2-weighted images. In conclusion, in clinical circumstances which various challenges exist to align the coils exactly on the same lines, array coils should be positioned at least within 2 cm from the center except for the upward direction, on the same line to prevent the image qualities are lowered.

Analysis of Distances for MRI Scan to Maintain Pptimal Signal Intensity in a Surface Coil (MRI 검사 시 코일내 최적의 신호강도를 유지할 수 있는 거리의 기준 분석)

  • Son, Soon-Yong
    • The Journal of the Korea Contents Association
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    • v.18 no.10
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    • pp.158-164
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    • 2018
  • The purpose of this study is to statistically analyze the signal intensity pattern according distance from the surface coil center and to maintain optimal signal intensity under clinical circumstances where the surface coil centers are not correctly positioned due to various causes. The cylindrical fluid phantom was placed and moved from the coil center in vertical direction with 1 cm increments. The signal intensities were measured and compared. As a result, the signal intensity showed no significant difference within 4 cm and 1 cm from in T1 weighted images while in T2 weighted images the signal intensity was maintained up to 5 cm and lower 3 cm in the upper and lower direction from the coil center. In conclusion, to maintain the optimal signal intensity the target region should be located within the reference distances proposed in this study.

Development of Multi-scale Model for Concrete Strength Estimation using Intelligent Self-diagnostic sensor (지능형 자가진단센서를 이용한 콘크리트 강도추정을 위한 다중스케일모델 개발)

  • Kim, Dong-Jin;Park, Woong-Ki;Lee, Chang-Gil;Hong, Seok-Inn;Park, Seung-Hee
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.303-306
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    • 2011
  • 본 논문은 콘크리트의 양생 강도 발현을 모니터링하기 위하여 매립형 압전 센서를 이용하여 콘크리트 내부의 임피던스 및 유도초음파 신호를 측정함으로써, 콘크리트의 양생 강도를 실시간 추정할 수 있는 기법을 개발하였다. 임피던스 및 유도초음파 신호는 구조물의 물성을 나타내며 특히 양생 기간 중 임피던스 및 유도초음파의 변화는 해당 콘크리트 구조물의 강도변화를 나타낼 수 있다. 이를 이용하여 매립형 압전 센서로부터 저비용의 셀프 센싱 기반 임피던스 및 유도초음파를 계측하여 콘크리트의 임피던스 공진 주파수 및 유도초음파의 전달 강도를 측정하고 측정된 신호를 통하여 콘크리트 양생 강도를 추정할 수 있게 된다. 제안된 기법의 적용가능성을 검증하기 위하여 설계 압축강도 30MPa의 콘크리트 슬라브 내부에 매립형 압전 센서를 매립하고 양생기간 동안 임피던스 및 유도초음파 신호를 측정, 비교 분석 하였다. 측정된 신호 및 압축강도를 통하여 임피던스 및 유도초음파 기반 강도 추정 모델을 도출하고 보다 높은 정확도를 얻기 위해 다중스케일 강도 추정 모델을 개발하였다. 결과적으로 본 연구를 통해 매립형 압전 센서를 이용하여 콘크리트의 양생 강도를 실시간 모니터링할 수 있음이 검증되었다.

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A Study of Signal Intensity of MRA in Flow Phantom of Fusiform Aneurysm (방추형 동맥류 모형에서 자기공명 혈관조영술의 신호강도에 대한 연구)

  • 한기석
    • Investigative Magnetic Resonance Imaging
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    • v.2 no.1
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    • pp.83-88
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    • 1998
  • Purpose : Authors correlated the three-dimensional time-of-flight MRA signal intensity characteristics and flow profile simulated by computer in an experimental flow phantom model. Materials and Methods : The three-dimensional time-of-flight MRA was performed in a fusiform flow phantom and analyzed the flow signal. computer assisted flow simulation was performed in same flow geometry. The MRA signal intensity and flow velocity distribution and direction was compared. Results : The flow was depicted as homogeneous signal internsity in inlet and outlet area and inhomogeneous signal intensity in fusiform area. Typically, the flow was depicted as target appearance in transition area to outlet. Whereas mean signal internsity decreased slowly in fusiform area, it rapidly dropped and resumed in transition area to outlet. In computer assisted flow simulation, Whereas there were flow velocity decrease and flow direction change to peripheral in entrance to fusiform area, ther were rapid flow velocity resuming and flow direction change to central in transition area to outlet. Conclusion : The signal loss and target appearance in transition area to outlet is characteristic of fusiform flow. These signal changes correlate with abrupt flow velocity and direction change well.

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The Relationship between Temporomandibular joint Pain and the Relative Signal Intensity of Retrodiscal Tissue on T1-, and T2-Weighted MRI Images (원판후조직의 T1, T2 강조영상상의 상대적 신호강도와 관절통증의 상관관계)

  • Jung, Jae-Kwang;Hur, Yun-Kyung;Choi, Jae-Kap
    • Journal of Oral Medicine and Pain
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    • v.36 no.3
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    • pp.177-185
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    • 2011
  • Aims: The purpose of this study was to evaluate the relationship between temporomandibular joint pain and the relative signal intensity (RSI) of retrodiscal tissue on T1-, and T2-weighted MRI images. Materials and Methods: This study was based on 122 TMJs of 61 patients who complain of TMJ pain in only one side but were revealed to have disc displacement in both TMJs according to MRI findings. The signal intensities of regions of interest (ROIs) in retrodiscal tissues were measured using T1-, and T2-weighted MRI images. The RSIs of retrodiscal tissues were referenced to the signal intensities of the ROIs of brain gray matter. The relationships between the RSI of retrodiscal tissue and joint pain, joint effusion, condylar degenerative change, and degree of disc displacement were examined. In addition, the relationships between joint pain and joint effusion, condylar degenerative change, and degree of disc displacement were examined. Results: On T1-weighted MR images, the painful TMJs showed significantly higher retrodiscal tissue RSI than non-painful TMJs. In addition, there is an association between joint pain and the degree of disc displacement. However, on T2-weighted MR images, the RSIs of retrodiscal tissues didn't show any significant differences with regard to joint pain, joint effusion, condylar degenerative change, and degree of disc displacement. Conclusions: The signal intensity of retrodiscal tissue can be used as a diagnostic marker for painful TMJ. However, the overall results suggest the signal intensity of retrodiscal tissue has a limited diagnostic significance in determining the pathologic status of TMJ.

Analysis of Signal Intensity in Choroid Plexuses by Diffusion Weighted Imaging (확산강조영상의 검사기법에 따른 맥락얼기의 신호강도 분석)

  • Oh, JongKap
    • Journal of the Korean Society of Radiology
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    • v.7 no.4
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    • pp.265-269
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    • 2013
  • This report aims at picturing out the clinical usefulness by analyzing the signal intensity in choroid plexuses which produce cerebrospinal fluids by diffusion weighted imaging. At first, subjects were chosen among the patients who showed high in signal intensity by diffusion weighted imaging. The subjects were taken another test by fluid attenuated inversion recovery diffusion weighted echo planer image(FLAIR-DW-EPI) the signals of fluid attenuation. And it was found that there are differences between the signal intensities of the two methods, which showed that the signal intensity in FLAIR-DW-EPI is equal to or low than, that in the Brain. By this, it is felt that it is helpful to diagnose the disease in choroid plexus by testing another more with FLAIR-DW-EPI methods the patients who showed high in signal intensity in choroid plexus by $T2^*$ diffusion weighted echo planer image($T2^*$-DW-EPI).

Assessment of Compressive Strength of Granitic Gneiss Using Nondestructive Testing based on Sound Energy (사운드에너지 기반 화강편마암의 비파괴 압축강도 산정)

  • Son, Moorak;Kim, Moojun
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.8
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    • pp.5-10
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    • 2018
  • This study provides a method to assess the compressive strength of granitic gneiss using total sound signal energy, which is calculated from the signal of sound pressure measured when an object impacts on rock surface, and its results. For this purpose, many test specimens of granitic gneiss were prepared. Each specimen was impacted using a devised device (impacting a specimen by an initial rotating free falling and following repetitive rebound actions) and all sound pressures were measured as a signal over time. The sound signal was accumulated over time (called total sound signal energy) for each specimen of granitic gneiss and it was compared with the directly measured compressive strength of the specimen. The comparison showed that the total sound signal energy was directly proportional to the measured compressive strength, and with this result the compressive strength of granitic gneiss can be reliably assessed by an estimation equation of total sound signal energy. Furthermore, from the study results it is clearly believed that the compressive strength of other rocks and concrete can be assessed nondestructively using the total sound signal energy.