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        • KCI등재
        • 확산과 관류자기공명영상의 임상적 적용 : 방사선과적 견해

          서정진 대한뇌졸중학회 2000 Journal of stroke Vol.2 No.1

          뇌졸중에서 확산이나 관류 자기공명영상의 임상 이용은 컴퓨터산업의 발달과 함께 급속도로 증가하고 있다. 이에 주로 이용되는 뇌경색 환자에서 임상 이용을 알아 보고자 한다. Korean Journal of Stroke 2000;2(1): 14~17

        • KCI등재
        • KCI등재

          저압배전선로 전압안정화를 위한 상태관측과 반복제어를 적용한 무효전력 보상기

          서정진,김영록,차한주 대한전기학회 2020 전기학회논문지 Vol.69 No.11

          In this paper, a new reactive power control algorithm using a stat observer and repetitive control for voltage adjustment to the low-voltage distribution line is proposed and verified by simulation and experiment. A reactive power compensator has a single -phase full bridge inverter structure and consists of DC voltage controller to maintain a constant DC voltage, and current controller for reactive power generation. A DC ripple compensation method use an output from the state observer and the output is used as the DC voltage controller feedback to regulate the DC voltage constant. In order to inject a stable reactive power, the fundamental component of current is controlled by a PI controller, and a repetitive controller is connected in parallel with the PI controller to compensate for lower-order harmonics. The repetitive controller, as implemented in the synchronous coordinate system, serves to eliminate low-order odd harmonic components. The proposed control technique is experimented with a ±5kVar single phase inverter system and verified the performance of the proposed algorithm by confirming that THD is reduced to 2% from 9%.

        • KCI등재후보

          뇌출혈의 확산강조 자기공명영상

          서정진,정광우,정용연,강형근,김태선,Seo,,Jeong-Jin,Jeong,,Gwang-U,Jeong,,Yong-Yeon,Gang,,Hyeong-Geun,Kim,,Tae-Seon 대한영상의학회 2002 대한영상의학회지 Vol.47 No.1

          목적:출혈성 뇌졸중 환자에서 뇌출혈의 각 시기별 혈색소 상태에 따른 고식적 T1,T2 강조영상의 신호강도를 근거로 하여 뇌출혈의 확산강조영상(diffusion weighted image ;DWI)에 서 신호강도변화를 알아보고자 하였다. 대상과 방법:출혈성 뇌졸중 환자 중 발병시기가 확실하고 DWI와 고식적 자기공명영상(MRI)을 시행한 34명의 환자를 대상으로 하였다.환자의 시기적 분류는 뇌졸중의 증상발현시간과 MRI시행과의 간격에 따라 급성기 (3일 이내)8예,초기 아급성기 (7일 이내)10예,후기 아급성기 (4주 이내)7예,초기 만성기(3개월 이내)4예,그리고 후기 만성기(3개월 이후)5예로 구분하였다.MRI는 1.5T 초전도 기기를 사용하였고,T1 강조영상(T1WI)과 고속스핀에코 T2 강조영상(T2WI)을 얻은 후 단발포에코평면영상기법을 사용하여 DWI를 얻었다.T1WI, T2WI와 DWI에서 뇌출혈병변 중심부의 육안적 신호강도를 알아보았고,각 영상에서 병변 중심부-정상 신호강도비(SIR)를 구하였다. 결과:병변 중심부의 신호강도는 급성기 8예중 5예(24 시간이내)에서 등 또는 고/고/고 (T1WI/T2WI/DWI)신호강도로 보였고,3예(72 시간이내)에서 저/저/저 신호강도를 보였으며 초기 아급성기 10예 모두에서 고/저/저 신호강도를,후기 아급성기 7예 모두에서 고/고/고 신호강도를,초기 만성기 4예 모두에서 고/고/고 신호강도를,그리고 후기 만성기 5예 모두에서 저/고/저 신호강도를 보였다.병변 중심부-정상 신호강도비는 급성기 중 T1WI에서 등 또는 고신호강도로 보인 5예에서 각각 1.42 $\pm$0.78/2.58 $\pm$0.84/1.35 $\pm$0.08 (T1WI/T2WI/ DWI),나머지 3예에서는 각각 0.94 $\pm$0.18/0.63 $\pm$0.16/0.27 $\pm$0.10,초기 아급성기에서는 각각 1.35 $\pm$0.01/0.97 $\pm$0.21/0.86 $\pm$0.22,후기 아급성기에서는 각각 1.58 $\pm$0.04/1.54 $\pm$0.09/1.44 $\pm$0.14, 초기 만성기에서는 각각 1.26 $\pm$0.11/1.06 $\pm$0.14/0.97 $\pm$0.12,그리고 후기 만성기에서는 각각 0.65 $\pm$2.23/1.51 $\pm$0.12/0.23 $\pm$0.18을 보였다. 결론:두개내 혈종은 DWI에서 T2WI를 반영하는 양상으로 관찰되었고 DWI에서 뇌출혈을 시 기에 따라 잘 이해를 하면 출혈성 뇌졸중환자에서 DWI를 해석하는 데 많은 도움이 되리라 생 각된다. Purpose: To determine changes in the signal intensity of intracerebral hemorrhagic lesions according to the time interval, between the onset of symptoms and MR imaging in the T1-weighted (T1W1), T2-weighted (T2W1) and diffusion-weighted modes. Materials and Methods: Thirty-four patients with hemorrhagic stroke who underwent DWI and conventional MRI were involved in this study. Hemorrhagic phase was determined according to the time interval between the onset of symptoms and MR scanning, and was as follows: acute (3 days or less): eight patients); early subacute (7 days or less): ten patients; late subacute (4 weeks or less): seven patients; early chronic (3 months or less) : four patients); and late chronic (more than 3 months): five patients. Using a 1.5T MR imager and the single-shot echo-planar imaging technique, T1-weighted, fast spin-echo T2-weighted, and diffusion-weighted were obtained. In all cases qualitative signal intensity (SI) at the center of a lesion was recorded, and the ratio between this and normal brain parenchyma was calculated. Results: SI at the center of a lesion was found to be iso or high/high/high (T1WI/T2WI/DWI) in five of eight acute-phase cases (interval of 24 hours or less) and low/low/low in the remaining three (interval of 72 hours or less). Other signal intensities were as follows: early subacute phase: high/low/low (all ten cases); late subacute phase: high/high/high (all seven cases); early chronic phase: high/high/high (all four cases); late chronic phase: low/high/low (all five cases). Mean SIRs were as follows: in the five acute-phase cases in which SI was iso or high: 1.42${\pm}$0.78 / 2.58${\pm}$0.84 / 1.35${\pm}$0.08 (T1WI / T2WI / DWI); in the remaining three acute-phase cases: 0.94 ${\pm}$0.18 / 0.63${\pm}$0.16 / 0.27${\pm}$0.10; in the early subacute phase, 1.35${\pm}$0.01 / 0.97${\pm}$0.21 / 0.86${\pm}$0.22 in early subacute phase, 1.58${\pm}$0.04 / 1.54${\pm}$0.09 / 1.44${\pm}$0.14; in the early chronic phase: 1.26${\pm}$0.11 / 1.06${\pm}$0.14 / 0.97${\pm}$0.12; and in the late chronic phase: 0.65${\pm}$2.23 / 1.51${\pm}$0.12 / 0.23${\pm}$0.18. Conclusion: The DWI findings of intracerebral hemorrhage reflect the findings of T2WI. When interpreting the DWI findings in patients with intracerebral hemorrhage, an understanding of the temporal evolution of this is very helpful . The no-show rate, patient distribution, chief complaint, type and number of additional radiologic examinations, patient compliance rate, biopsy result, rate of cancer detection, and staging of cancers were determined. The merits and demerits of the clinic were also assessed. Results: A total of 671 patients attended, with a no-show rate of 13.2%. Referrals from the Health Promation Centre accounted for 90.4% of patient visits. The most frequent complaint was a suspicious nodule at mammography. One additional radiologic examination was performed in 429 patients, two examinations in 70, and three or more examations in five. The most frequent type of examination was ultrasonography, followed by magnification compression view, mammography, and ultrasound-guided aspiration biopsy. An additional radiologic examination was recommended in 81.2% of patients and compliance rate was 96.7%. Primary breast cancer was diagnosed in 16 patients (2.1%), and was found to be stage 0 and 1 in 64.3% of these. No significant demerits were apparent. Conclusion: Radiologic examinations play a very important role in the detection of early-stage breast cancer, and the establishment of an early detection clinic lead by a radiologist is a very effective and recommendable approach to screening.',PY = '2002-00-00',RF = '5',BN = '

        • SCOPUSKCI등재

          피록시캄의 용매 비의존 결정구조

          서정진,김봉희,서일환,지옥인,서종명 한국약제학회 1988 Journal of Pharmaceutical Investigation Vol.18 No.4

          The three-dimensional structures of piroxicam crystallized from two different solvents, toluene and toluene/hexane mixture respectively, are proved identical: C₁5H₁3N₃O₄S, M = 331.35, monoclinic, a = 7.128(1), b = 15.146(2), c = 13.956(2) Å, β= 97.33(1)°, V = 1494.37ų, Dx = 1.472 g/cm³, Z = 4, space group P2₁/c, Mo Kα(&= 0.71073 A), F(000) = 688, T = 295 K, R = 0.0611 for 1993 unique observed reflections. The thiazine ring exhibits a half chair conformation. An amide group is involved in an intramolecular hydrogen bond to the hydroxy group, O(17)-H(17)…O(15)Å. The molecule is planar within 2 Å with the interplanar angle 127.9(4)° between pyridine and benzene rings. A molecular chain parallel to [011] is formed by two intermolecular hydrogen bonds N(16)-H(6)…O(11) and C(6)-H(6)…O(11), and the molecular chains are held together by van der Waals forces.

        • KCI등재
        • KCI등재

          풍성 카테타를 이용한 식도 성형술

          서정진 대한영상의학회 1990 대한영상의학회지 Vol.26 No.2

          Most benign esophageal strictures can be successfully dilated with conventional bougienage technique. But occasionally strictures are so tight, lengthy, or sometimes irregular that this technique fail and surgical intervention is required. Since 1974 Gruentzig balloon catheter has succeeded when used for strictures in the cardiac and peripheral vasculatures, the biliary and urinary tracts, the colon of neonates after inflammatory disease and also in the esophagus. fluoroscopically guided balloon catheters were used to dilate 30 esophageal strictures in30 patients over 3 years at department of Diagnostic Radiology Chonnam University, College of Medicine. The distribution of age was from 7 years to 71 days and the ratio of male to female was 15 : 15. The causes of benign stricture (23 cases) were post-operative strictures (13), chemical (4), achalasia 93), chronic inflammation (2), esophageal rupture 91) and those 0f malignant stricture 97 cases) were post-radiation stricture of primary esophageal cancer 96) & metastatic esophageal cancer 91). The success rate of procedure was 93% (28/30). The causes of failure were the failure of passage of stricture due to markedly dilated proximal segment of esophagus 91 case) and too long segment of stricture (1 case). Complication of procedure was the diverticula-formation of esophagus in 3 cases, but has no clinical significance in follow-up esophagography. In conclusion, fluoroscoically guided ballon dilation of esophageal stricture appears to be safe, effective treatment and may be have theoritical advantages over conventional bougienage and also should be considered before other methods of treatment are used.

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