슈퍼커패시터용 그래핀-산화아연 전극의 급속열처리에서 수소의 영향

정우준(Woo-Jun Jeong),오예찬(Ye-Chan Oh),김상호(Sang-Ho Kim) 한국표면공학회 2019 한국표면공학회지 Vol.52 No.3

With recent demand for the renewable energy resources, we conducted a research on the energy conversion and storage device of supercapacitor. The hybrid graphene-zinc oxide(GZO) electrodes for the supercapacitors (SCs) were fabricated and investigated. To increase the electrical conductivity of the GZO electrode, the rapid thermal annealing(RTA) in Ar/H₂(10%) atmosphere was applied and the effect was examined by comparing it with RTA at Ar atmosphere. In Raman spectroscopy, the electrodes annealed at 400? in Ar/H₂ atmosphere showed a lower ratio of D/G peak than that of annealed at Ar atmosphere, and had a larger specific capacitance(Sc) in the cyclic voltammetry(CV), and a lower the equivalent series resistance(ESR) in the electrochemical impedance spectroscopy(EIS). The reason seems to come from the better mixing of the graphene and zinc oxide by the RTA in Ar/H₂(10%).

슈퍼커패시터용 그래핀볼 - 그래핀옥사이드 복합전극의 전기화학적 특성

정우준(Woo-Jun Jeong),오예찬(Ye-Chan Oh),김상호(Sang-Ho Kim) 한국표면공학회 2020 한국표면공학회지 Vol.53 No.5

Composite material of the graphene ball (GB) inserted graphene oxide (GO) sheet for a supercapacitor electrode was studied. Chemical vapor deposition (CVD) process used to make GBs on the silicon oxide nanoparticles. The GBs mixed into the GO sheets to make GOGB and reduced it to create a reduced GOGB(RGOGB) composite. The RGOGB composite electrode had a large surface area and improved electrochemical properties. Specific capacitance of the RGBGO composite electrode was higher over 20 times than a pure GO and GOGB electrode in cyclic voltammetry(CV) tests, and the Z’ and Z” impedance measured by an electrochemical impedance spectrometry(EIS) also low. So, the RGBGO composite electrode would use effectively to expand a performance of supercapacitor.

경부 CT검사시 선속경화현상 감소를 위한 환자 자세 및 영상 평가

정우준(Woo Jun Jeong),신훈(Hoon Sin),오용운(Yong Woon Oh),김진배(Jin Bae Kim),조인완(In Wan Cho),구상진(Sang Jin Gu),유병헌(Byeong Heon Yoo) 대한CT영상기술학회 2009 대한CT영상기술학회지 Vol.11 No.1

Purpose The goals of this study was to examine the changes of beam hardening effect in shoulder and to evaluate the change of image quality which follows in positional change in patients with neck diseases. Materials and methods 30 patients with neck diseases were included in this study and 16-slice MDCT (Sensation 16, Siemens, Erlangen, Germany) was undergone. Positions of patients had changed with time such as neutral position with(group N), position with raising left arm (group S), and position with getting off everted both arms maximally(group P). ROI (1cm in area) located at supraclavicular fatty tissue for measuring CT noise was measured(3 times) and an average was recorded. For analysis of radiation exposure, parameters were fixed and scanned topograms of changed positions were compared with CTDIvol values measured at same position. Two investigators assessed image qualities, which were graded to unacceptable, suboptimal, adequate, good, excellent diagnostic quality. Results In CT noise, group S and group P showed 23% and 19% decrement rather than those of group N respectively. In radiation exposure, group S and group P showed 12% and 11% decrement rather than those of group N respectively. In 30 patients, image qualities of group N, group S, and group P were analyzed to unacceptable(n=0, 0, 0), suboptimal (n=0, 28, 2), adequate (n=24, 26, 3), good (N=28, 6, 22), and excellent diagnostic quality (n=8, 0, 33). Conclusion Appropriate positional change in neck CT scanning is useful method for obtaining images of improved quality and reducing beam hardening effect by shoulder.

Tuning PID Controllers with Preserved via Reinforcement Learning Approaches

Jeong Woo Jun(정우준),Lee Dong Gyu(이동규),Lee Donghwan(이동환) 한국통신학회 2023 한국통신학회 인공지능 학술대회 논문집 Vol.2023 No.9

Brain Perfusion CT검사 시 재구성 영상기법을 이용한 선량 감소 효과에 관한 연구

주명식(Myeong Sik Ju),백동오(Dong Ho Baek),정우준(Woo Jun Jeong),오용운(Yong Hoon Oh),김현주(Hyeon Ju Kim),조인완(Yin Hwan Jo),유병헌(Byeong Hun Yoo) 대한CT영상기술학회 2011 대한CT영상기술학회지 Vol.13 No.2

목적 BrainPerfusion CT 검사 시 재구성영상기법을 이용한 피폭선량 감소와 영상분석을 통한 유용성을 알아보고자 한다. 대상 및 방법 본 연구를 위해 사용한 장비는 64-MDCT (LightSpeed VCT Xte, GE Healthcare, Milwaukee, USA)를 사용하였으며 영상획득은 BrainPerfusion CT검사 시 사용된 영상 매개 변수로 40mm Detector Coverage, 0.625 mm의 helical thickness이며 scan type은 helical shuttle mode, rotation time은 0.5sec로 설정하여 팬텀 실험과 동물 실험을 하였다. 획득된 Raw Data는 장비 자체에서 재구성을 하였고 재구성 방법으로는 ASIR(Adaptive Statistical Iterative Reconstruction, 이하 ASIR) 기법을 이용하였다. 선량 및 노이즈 측정은 Advantage Workstation(Version 4.4, GE, USA)을 이용하였으며 SPSS(12.0.1)의 paired T-test로 통계적 유의성을 검증하였다. 팬텀과 동물실험에서 노이즈 측정은 관전압을 80kVp로 고정, ASIR 수준을 10% 간격으로 0~100%로 변화시키면서 스캔하여 CT계수의 표준편차(SD)를 3회씩 측정한 후 평균값을 분석하였다. 팬텀과 동물실험의 선량 측정 방법은 노이즈 검사와 동일한 조건하에서 흡수선량을 10회 측정 후 평균값을 분석하였으며 동물실험의 경우 돼지머리의 뇌 중심부에 연필형 CT전용 ionization chamber를 삽입 후 측정하였다. 결과 팬텀과 동물실험의 노이즈 측정값은 각각 %에 28.20HU, 34.76HU, 10% 27.18HU, 35.15HU, 20% 25.86HU, 34.97HU, 30% 25.41HU, 35.91HU, 40% 24.15HU, 33.77HU, 50% 22.10HU, 31.84HU, 60% 20.32HU, 34.32HU, 70% 18.23HU, 33.90HU, 80% 16.65HU, 34.295HU, 90% 14.86HU, 36.65HU, 100% 14.38HU, 37.41HU로 측정되었으며 통계적 분석 결과 각각 p = 0.002(p < 0.05) p = 0.001(p < 0.05)로 통계적으로 유의한 차이가 있었다. 팬텀과 동물실험의 선량 측정값은 각각 %일 때 11 mGy, 4mGy, 10% 9.1 mGy, 3.2mGy, 20% 8.4mGy, 3mGy, 30% 7.8mGy, 2.7 mGy, 40% 6.5mGy, 2.3 mGy, 50% 6.1 mGy, 2mGy, 60% 5.4mGy, 1.8mGy, 70% 4.7 mGy, 1.6mGy, 80% 4mGy, 1.3mGy, 90% 3.5mGy, 1.2mGy, 100% 3 mGy, 1 mGy로 측정되었으며 통계적 분석 결과 각각 p = 0.001(p < 0.05), p = 0.001(p < 0.05)로 통계적으로 유의한 차이가 있었다. ASIR수준을 10~100%까지 변화를 주어 두부 전문 판독의 2명(A, B)에게 두부 CT영상의 화질 평가 항목 중 영상정보 항목에 해당하는 내용을 점수화 하여 Kruskal-Wallis test를 이용하여 검정한 결과 A, B관찰자 모두 ASIR 수준이 40%일 경우 평균 순위 최저 6.0, 최고 11.0으로 평가되었으며 p=0.0278(p < 0.05)로 통계적으로 유의한 차이가 있었다. 결론 임상에서 BrainPerfusion CT와 같이 피폭선량이 많은 검사의 경우 Filtered backprojection 재구성기법을 이용하는 대신 Iterative Reconstruction 기법을 적용하여 검사를 시행한다면, 영상화질의 큰 변화 없이 피폭선량의 감소 효과까지 기대할 수 있을 것으로 사료된다. I. Purpose The usability through exposure dose reduction using the reconstruction image technique in the Brain Perfusion CT scan and image analysis tries to be examined. II. Meterial and Methods The equipment is for and using this research used 64-MDCT (LightSpeedVCTXte, GE Healthcare, Milwaukee, USA) and the image acquisition was 40 mm Detector Coverage and helical thickness of 0.625 mm with the image parameter used during the Brain Perfusion CT scan and it set as 0.5 sec and the helical shuttle mode and rotation time did the scan type about the phantom experiment and animal experiment. The obtained raw data reconstructed in the device itself and used ASIR (the Adaptive Statistical Iterative Reconstruction or less ASIR) technique as the reconfiguration method. A dose and noise measuring used the Advantage Workstation (Version 4.4, GE, USA) and verified the statistical significance with the paired T-test of the SPSS (12.0.1). After diversifying VRMS a fixing and ASIR level into 80 kVp 10% into 0~100% and scanning and 3 times measuring the standard deviation (SD) of the CT count, the noise measuring analyzed an average in a phantom and animal experiment. In the same under condition as the noise examination, a dosimetry method of a phantom and animal experiment analyzed an average after 10 time measurement and after inserting the pencil CT exclusive ionization chamber in the case of the animal experiment in the pineal region of the pig head, it measured the absorbed dose. III. Result There was the difference in which the noise treasured value of a phantom and animal experiment was measured by 0% 28.20HU, 34.76HU, 10% 27.18HU, 35.15 HU, 20% 25.86 HU, 34.97 HU, 30% 25.41 HU, 35.91 HU, 40% 24.15 HU, 33.77HU, 50% 22.10HU, 31.84HU, 60% 20.32HU, 34.32 HU, 70% 18.23HU, 33.90HU, 80% 16.65HU, 34.295HU, 90% 14.86HU, 36.65HU, 100%, 14.38HU, 37.41HU and which the statistical analyzed result notes statistically with the p = 0.002 (p < 0.05), p = 0.001 (p < 0.05). There was the difference which was measured by 0% 11mGy, 4mGy, 10% 9.1mGy, 3.2mGy, 20% 8.4mGy, 3mGy, 30% 7.8mGy, 2.7mGy, 40% 6.5mGy, 2.3mGy, 50% 6.1 mGy, 2mGy, 60% 5.4mGy, 1.8mGy, 70% 4.7mGy, 1.6mGy, 80% 4mGy, 1.3mGy, 90% 3.5mGy, 1.2mGy, 100% 3 mGy, 1 mGy and which the statistical analyzed result the dose measured value of a phantom and animal experiment notes statistically with a p = 0.001 (p < 0.05) and p = 0.001 (p < 0.05). IV. Conclusions In a clinical, the exposure dose uses the Filtered backprojection reconstruction technique like the Brain Perfusion CT for many inspections, and instead by applying the iterative reconstruction technique, an inspection is enforced. If it is the case, it is considered to expect the diminished effect of the exposure dose without the big change of the display-image quality.

Comparative Analysis and Usefulness by Quantitative Evaluation of Deep Learning Image Reconstruction and Adaptive Statistical Iterative Reconstruction-V in Aortic Vessels CT

고창수(Chang-Su Ko),조인완(In-Wan Cho),강지원(Ji-Won Kang),정우준(Woo-Jun Jeong),송훈(Hoon Song) 대한CT영상기술학회 2021 대한CT영상기술학회지 Vol.23 No.2

기존의 ASIR-V 기법과 DLIR 기법을 이용하여 영상을 재구성한 후, 정량적 비교평가를 통한 DLIR 기법의 유용성에 대하여 확인해 보고자 한다. Phantom을 이용하여 구조적 유사지수(SSIM), 신호 대 잡음비(SNR)와 대조도 대 잡음비(CNR)을 비교분석하였다. 또한 대동맥 혈관 CT(AVCT) 검사를 진행한 환자들의 영상을 바탕으로 Phantom과 동일한 방법으로 SNR과 CNR을 비교분석 하였다. 측정된 SSIM 값은 두 기법간의 영상을 서로 비교한 평균 값에서 TF와 SSIM 값이 높게 측정 되었다. Phantom을 이용한 SNR 측정값을 토대로 한 두 기법 간의 통계적 유의성 검증 결과 모든 플러그에서 통계적으로 유의한 결과를 보였다.(p<0.05) CNR 측정값을 토대로 한 통계적 유의성 검증 결과에서는 TF-H와 ASIR-90%의 Brain 플러그에서는 통계적으로 유의한 수준을 나타내지 않았으며,(p>0.05) 그 외 다른 플러그에서는 통계적으로 유의한 결과를 보였다.(p<0.05) AVCT를 검사를 진행한 환자들의 조영 전과 조영 후 영상에서의 SNR값은 통계적으로 유의한 결과를 보였다.(p<0.05) CNR값의 통계적 유의성은 조영 전 영상에서는 하행 대동맥 측정영역에서만 통계적으로 유의한 결과를 보이지 않았으며,(p>0.05) 나머지 부위에서는 통계적으로 유의한 수준을 나타냈다.(p<0.05) 조영 후 영상에서는 모든 관심 부위에서 통계적으로 유의한 결과를 보였다.(p<0.05) DLIR 기법은 영상의학과 판독의와 임상의에게 정확한 진단을 결정하는데 많은 도움을 줄 수 있으며 AVCT검사에서 기존의 영상 재구성 기법에 비해 보다 나은 최적의 영상을 획득할 수 있는 재구성 기법으로 충분한 가치가 있다고 사료된다. We studied that how the Deep Learning Image Reconstruction(DLIR) technique was useful through comparative evaluation after reconstructing the images by conventional ASIR-V technique and DLIR technique. We measured SSIM with PBU-60 Phantom and compared SNR and CNR by the each tissue equivalent material, using Tomotherapy Cheese Phantom. Also SNR and CNR were compared in the same way with phantoms, using the patients’ aortic vessels CT images. As a result of comparing average of SSIM from the images reconstructed by ASIR-V technique and True-Fidelity(TF) images which were reconstructed by DLIR, the average of SSIM from TF was higher than the average of SSIM from ASIR-V. In the using Phantom the result that based on SNR between two techniques had statistical significance.(p<0.05) The result that based on CNR was significant statistically in all the plugs except for the case of CNR from TF-H and ASIR 90% at the plug of brain. SNR result, there was statistical significance between the two techniques(p<0.05) in both cases of pre and post enhanced AVCT images from the patients. At the pre-enhanced images, CNR from every part had significant result statistically except for the part of descending aorta from TF-H and ASIR-90%. However, there was statistical significance in the post-enhanced images of every ROI.(p<0.05) DLIR technique help the radiologist and the clinicians diagnose the diseases accurately. Compared to the conventional technique reconstructing the images in AVCT, it would be good enough to get much more high-quality images.