• Title, Summary, Keyword: b-value

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Changes in SNR and ADC According to the Increase in b Value in Liver Diffusion-Weighted Images

  • Cho, Jae-Hwan;Kim, Ham-Gyum
    • Journal of Magnetics
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    • v.17 no.3
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    • pp.219-224
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    • 2012
  • In the present study, changes in signal-to-noise ratio (SNR) and apparent diffusion coefficient (ADC) of the diffusion-weighted images in the normal livers were investigated using changes in b values in 1.5 T MR (magnetic resonance) instruments. Respective diffusion-weighted images and ADC map images were obtained from 20 healthy individuals by increasing b values from 50 to 400 and 800 $s/mm^2$ using 1.5T MR scanner between January 2011 and November 2011. At each ADC map image obtained at each b value, ADCs in the right hepatic lobe, spleen and kidney were measured. As a result, ADCs of the right hepatic lobe, spleen and kidney have gradually decreased in the diffusion-weighted images in accordance with the reduced b value. This outcome may be used as preliminary data for applications to various abdominal diseases.

The Research of Commercial HTPB Polymer Binder Characteristics for Castable Plastic Bonded Explosive (주조형 복합화약용 HTPB 고분자 바인더의 상용모델 특성연구)

  • Lee, Seung-Jae;Kim, Jae-Woo;Park, Jong-Wan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.441-444
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    • 2011
  • Type A and Type B and are commercial HTPB models, which are very popular prepolymer for polyurethane binder family. So the study has been performed on the physical, chemical characteristic of HTPB and viscosity, mechanical property of PBX-A applying to HTPB. But We excluded the Type A from Appication test, because of law Hydroxyl value. And in the case of Type B, Type B-1, 2 has mechanical disadvatage to apply to HTPB in the process comparing with B-3. It seems to make no problem if we change equivalence ratio or curing condition within standards. But if we are to apply process condition like R-45HT(US-sample), it would be essential to apply HTPB with higher Hydroxyl Value and hydroxyl Functionality.

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Fracture Characteristics of the Resistance Spot Welded Joints by Acoustic Emission (음향방출법에 의한 저항 점용접부의 파괴특성에 대한 연구)

  • Jo, Dae-Hee;Rhee, Zhang-Kyu;Park, Sung-Oan;Kim, Bong-Gag;Woo, Chang-Ki
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.2
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    • pp.14-22
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    • 2007
  • In this paper, the acoustic emission(AE) behaviors were investigated with single-and 2-spot resistance spot welded SPCC specimens. Test specimens were welded horizontally and/or vertically according to the rolling direction of base netal in 2-spot welding. In the case of 2-spot welding, when tensile-shear test has below amplitudes: crack initiation $50{\sim}60dB;$ tear fracture $40{\sim}50dB$. And when cross tensile test has below amplitudes: early stage $75{\sim}85dB;$ yielding point $65{\sim}75dB;$ post yielding $40{\sim}60dB;$ plug fracture $70{\sim}80dB\;or\;90{\sim}100dB$. Also, from the b-value that is slope of AE amplitude, we knew that there are lots of low amplitudes if b-value is big(i.e., tensile-shear $specimen{\rightarrow}tear$ fracture or shear fracture), and there are lots of high amplitudes if b-value is small(i.e.. cross tensile $specimen{\rightarrow}plug$ fracture). As the results of fiacture mechanism analyses through AE amplitude distributions, change of the b-value represented fracture patterns of materials. Correspondingly, low amplitude signals appeared in crack initiation, and high amplitude signals appeared in base metal fracture. We confirmed that these amplitude distributions represented the change or degradation of materials.

Study of Apparent Diffusion Coefficient Changes According to Spinal Disease in MR Diffusion-weighted Image

  • Heo, Yeong-Cheol;Cho, Jae-Hwan
    • Journal of Magnetics
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    • v.22 no.1
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    • pp.146-149
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    • 2017
  • In this study, we compared the standardized value of each signal intensity, the apparent diffusion coefficient (ADC) that digitizes the diffusion of water molecules, and the signal to noise ratio (SNR) using b value 0 400, 1400 ($s/mm^2$). From March 2013 to December 2013, patients with suspicion of simple compound fracture and metastatic spine cancer were included in the MR readout. We used a 1.5 Tesla Achieva MRI system and a Syn-Spine Coil. Sequence is a DWI SE-EPI sagittal (diffusion weighted imaging spin echo-echo planar imaging sagittal) image with b-factor ($s/mm^2$) 0, 400, 1400 were used. Data analysis showed ROI (Region of Interest) in diseased area with high SI (signal intensity) in diffusion-weighted image b value 0 ($s/mm^2$) Using the MRIcro program, each SI was calculated with images of b-value 0, 400, and 1400 ($s/mm^2$), ADC map was obtained using Metlab Software with each image of b-value, The ADC is obtained by applying the ROI to the same position. The standardized values ($SI_{400}/SI_0$, $SI_{400}/SI_0$) of simple compression fractures were $0.47{\pm}0.04$ and $0.23{\pm}0.03$ and the standardized values ($SI_{400}/SI_0$, $SI_{400}/SI_0$) of the metastatic spine were $0.57{\pm}0.07$ and $0.32{\pm}0.08$ And the standardized values of the two diseases were statistically significant (p < 0.05). The ADC ($mm^2/s$) for b value 400 ($s/mm^2$) and 1400 ($s/mm^2$) of the simple compression fracture disease site were $1.70{\pm}0.16$ and $0.93{\pm}0.28$ and $1.24{\pm}0.21$ and $0.80{\pm}0.15$ for the metastatic spine. The ADC ($mm^2/s$) for b value 400($s/mm^2$) was statistically significant (p < 0.05) but the ADC ($mm^2/s$) for b value 1400 (p > 0.05). In conclusion, multi - b value recognition of signal changes in diffusion - weighted imaging is very important for the diagnosis of various spinal diseases.

Quantitative, qualitative Evaluation of Diffusion-Weighted MRI using Optimal b-value(s/mm2) for Female Pelvis (여성골반에 대한 최적의 b-value(s/mm2)를 이용한 확산강조 자기공명영상의 정량적, 성적 평가)

  • Goo, Eun-Hoe
    • Journal of Digital Convergence
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    • v.11 no.1
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    • pp.361-368
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    • 2013
  • The purpose of this study is to know the clinical usefulness of optimal b-values by quantitative, qualitative evaluation of DW-MRI for lesions of benignity and malignity of female pelvis. The b-values used in DWI were 600, 800, 1000, 1200, 1400($s/mm^2$). Mean SNR and CNR of myoma in b-value 800 were the highest result as $84.6{\pm}4.57$(p=0.024) and $50.13{\pm}5.47$(p=0.028), Mean SNR and CNR of cervical cancer were the highest result as $12.0{\pm}2.04$(p=0.047) and $10.6{\pm}1.24$(p=0.001), Mean ADC value in myoma and cervical cancer in b-value 800 were $1.19{\times}10^{-3}mm^2/s$(p=0.008), $0.96{\times}10^{-3}mm^2/s$(p=0.027). As a qualitative analysis, the delineation and conspicuity were the highest result as $4.02{\pm}0.18$(p=0.028), $4.39{\pm}0.25$(p=0.015) on b-value 800. DW-MRI is an important method, and the optimal b values is 800 $s/mm^2$ for differentiation between benign and malignant lesions of female pelvis.

A study on the amylase in serum and urine in open heart surgery under the extracorporeal circulation (체외순환 개심술 환자의 혈청 및 뇨중 Amylase 변동에 관한 연구)

  • Lee, Byeong-U;Kim, Geun-Ho
    • The Korean Journal of Thoracic and Cardiovascular Surgery
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    • v.16 no.1
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    • pp.83-90
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    • 1983
  • During the period of March 1981 to September 1982 a series of survey has been done on the value of amylase in blood and urine of 24 patients who went through the operation of heart surgery, for congenital and acquired heart diseases, with extracorporeal circulation at the Department of Thoracic _ Cardiovascular Surgery, School of Medicine, Hanyang University. In order to analyze the iteration and inter-relation of the value of amylase in blood and urine and the extra corporeal circulation time. The duration of extra-corporeal circulation time up to 60 minutes was classified as Group A while above 60 minutes was classified as Group B. The results are as follow; 1. 3 patients [23.07%] among 13 patients of Group A and 3 patients [27.27%] among 11 patients, showed increased amylase value after the surgery. 2. The average value in blood after operation was 120.3190.71 unit in Group A and 130.90113.15 unit in Group B. It was 11.59 units [9.63%] higher in Group A than in Group B. 3. 1 patient [7.7%] among 13 patients of Group A and 2 patients[18.18%] among 11 patients of Group B, the frequency of Group B was 10.48% higher. 4. The average Value of amylase in urine after the surgery was 111.9254.87 unit in Group A and 151.54111.17 unit in Group B. It was 39.62 unit [32.72%] higher in Group A than in Group B. 5. The longer the duration of extra corporeal circulation time showed the higher the amylase value in blood and urine after the operation. 6. Although the value of amylase in blood and urine was increased after operation, no patients Were found to have developed clinical pancreatitis.

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Usefulness of the High B-value DWI in Brain Tumors (뇌종양 확산강조영상에서 High B-value의 유용성 평가)

  • Kim, Jin-tae;Byun, Jae-Hu;Park, Yong-Seong;Lee, Rae-Gon;Hwang, Seon-Kwang
    • Korean Journal of Digital Imaging in Medicine
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    • v.17 no.1
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    • pp.33-41
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    • 2015
  • This study attempts to examine the clinical usefulness of High b-value DWI (diffusion weighted imaging) for brain tumors with an edema. Subjects were seven patients selected from 65 patients who received an MRI scan for suspected encephalopathy and confirmed diagnosis at our hospital from February to July 2015 (male: 7, average age : 66 years old). As test equipment, 3.0T MR System (ACHIEVA Release, Philips, Best, The Netherlands) and 8Channel SENSE Head Coill were used. DWI checks on the use of the variable TR 5460ms, TE 132ms, Slice Thickness 4mm, gap 1mm, Slice number 29 is, 3D T1WI is TR 8.4ms, TE 3.9ms, matrix size $240{\times}240$, Slice can set 180 piecesIt was. b value of 0, 1,000, 2,000 s/mm2 with DWI acquisition and 3D T1WI enhancement five minutes after the Slice Thickness 3mm, gap 0mm to reconstruct the upper face axis (MPR TRA CE) was. As for the experiment, in b-value 1,000 and 2,000 images, SNR and the lesion at the lesion site and CNR in the normal site opposite to the lesion are measured. WW(window width) and WL(window level) are made equal in MRICro software, and the volume of the lesion is measured from each of b-value and MPR TRA CE image. Using SPSS ver. 1.8.0.0 Mann Whitney-test was analyzed for SNR and CNR, while Kruskal-Wallis test was analyzed for volume.

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Design of White Balance Correction Processor for High Resolution Full Color LED Display System (고해상도 천연색 LED 디스플레이 시스템을 위한 흰색 보정프로세서의 설계)

  • Lee, Jong-Ha;Ko, Duck-Young
    • 전자공학회논문지 IE
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    • v.46 no.3
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    • pp.12-18
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    • 2009
  • In this paper, we developed white balance correction processor for Full Color LED Display System which could be display uniformity color and soft light by adjusting brightness of red, green, blue pixel, individually. This processor correct brightness by calculating operating current of each pixel(red, green, blue LED) on the basis of characteristic curve of LED device when we named "a" as a specific characteristic value, "b" as a brightness correction value according to using time, "X" as a operating current value, and "Y" as brightness value. As the results, we solved the reduction problem of brightness for long used LED devices, according to increase entire mean of brightness value by adjusting "b" value from the brightness characteristic function.

A Study on Some Antioxidative Effects of Stewed Pumpkin Juice on Lipid (호박즙의 유지에 대한 항산화 효과)

  • 오봉윤;박복희
    • Korean Journal of Human Ecology
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    • v.1 no.2
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    • pp.89-99
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    • 1998
  • This study was carried out to investigate some antioxidative effects of stewed pumpkin juice (SPJ) and the SPJs added with ginger (SPJ-G), onion (SPJ-O), jujube (SPJ-J) or boxthorn (SPJ-B), respectively, on the lipid oxidation of soybean oil (S) and mackerel pike boiled ground (MPBG). Antioxidative substances of SPJ were extracted by using the two solvent layers of n-hexane:acetone (1:1)(H) and methanol:water (7:3)M. The antioxidative effects of the extracts were observed by the peroxide value (P.O.V.) and thiobabituric acid (T.B.A.) value. The P.O.V. and T.B.A. value of two solvent extracts of S and MPBG showed significantly lower than those of S and MPBG. The SPJ showed very distingnished antioxidative effects. It was considered that melanoidine extracted by using methanol:water (7:3) solvent as well as carotenoid extracted by using n-hexane:acetone (1:1) solvent had an antioxidative effect. During storage, T.B.A. value of MPBG significantly increased, while that of MPBG-SPJ significantly decreased more than that of MPBG. T.B.A. value of MPBG-SPJs decreased much than that of MPBG-SPJ, SPJ-O, SPJ-G, SPJ-J and SPJ-B, in order of abundance, showed higher level of antioxidative effects than SPJ. (Korean J Human Ecology 1(2):89∼99, 1998)

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The Impact of Customer Value on Relationship Continuity -Focusing on transaction value, relationship value, appraisal value- (기업 간 거래에서 고객가치가 거래지속성에 미치는 영향 -거래가치, 관계 가치, 평가적 가치를 중심으로-)

  • Kim, Hyang-Mi;Lee, So-Young
    • Journal of Digital Convergence
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    • v.14 no.9
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    • pp.123-132
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    • 2016
  • This study starts from the research question that "Why some companies decide to keep working in partnership even when they are not satisfied with the partner companies simply because they are old business partners." The authors try to find the answer in terms of customer value considering the phases of B2B transaction spectrum: transaction value, relationship value and appraisal value implementing empirical research. The result shows that the intension to retain the relation with an existing partner is formed by the trade-off between the benefit and cost of both contract value and relationship value and not the sole value was dominant. The unique point of the study is that current study is considering these two factors as dependent variables which affect the relationship continuity which is not the case in existing researches.