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RISS 인기검색어
- 검색키워드
- 저자 : 李成吉 (검색결과 149 건)
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고주파 공진형 인버터식 X선발생장치의 관전압 불균형 개선
이성길,김영근,박수강 광주보건대학 2000 論文集 Vol.25 No.-
In order to radiate X-ray, the low ripple stabilized high voltage DC over the range of 40kV to 150kV is directly inflicted to X-ray tube. The energy characteristics of the radiated X-ray depend on the pulsating waveforms of the DC voltage supplied X -ray tube. In general, the low ripple voltage waveforms with fast rising times are required to increase with the dosage per unit time lest the exposure time should be longer in order that the motion artifacts of an object may be eliminated in actual. The rotating anode and the cathode of the metal-envelope X-ray tube are incorporated into an envelope made of metal, for instance stainless steel and copper, instead of hard glass. This metal envelope is able to collect the secondary electrons which causes harmful influence to thequality of the diagnostic images. Furthermore, the metal-envelope X-ray tube has mechanically higher strength than glass-envelope type, and so it suits for high power X-ray system. For those benefits, this type of X-ray tube is mainly used to obtain the high quality diagnostic images in X-ray angiography and X-ray computed tomography. The electrons collected at th envelope generate the eletric current flow form the ground to the cathode and occasionally the unmatched impedance of the anode side and the cathode side of the X-ray tube. The unmatched impedance causes the remarkable imblacne of the output voltage of the series resonant inverter-fed converter. In this paper, the newly-developed converter to take the balance of the output voltage versus the ground are also presented in detail. This converter consists of the two independent series resonant circuit using the two capacitance and the two parimary winding high-voltage transformer.
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이성길,김영근,김창복 광주보건대학 2004 論文集 Vol.29 No.-
It is important to control resolution for maintenance of good image quality in fluoroscopic unit. This study is to analyze current situation on control of image quality in fluoroscopic unit. Between the sixth and the twenty eighth March 2003, 77 fluoroscopic units in 40 hospitals in Seoul and Kyung-gi area were tested with fluoroscopic phantom(CDRH phantom, Nuclear associates, USA) and image quality test tool including hight contrast resolution patterns and low contrast objects. We exposed radiation in condition of colon study, and then counted the number of patterns on monitor, printed spot film, and printed abdominal film. In the test on monitor, suitable unit within standard number in hight contrast and low contrast test were 68(88%), 49(64%), respectively, and in the test on printed spot film 73(95%), 67(87%), respectively. The cases within standard number in hight contrast and low contrast test on all the two monitor and printed spot film were 44(57%), 65(84%), respectively. Thradiation was exposed from 100 to 120Kvp in fluoroscopy, and spot radiography 80 to 110Kvp mainly. In conclusion, it is necessary that image quality control is done continuously by standard of image quality control suitable for current situation.
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放射線 安全管理에 對한 調査硏究 : 全南地域을 中心으로
李成吉 광주보건대학 1985 論文集 Vol.10 No.-
This survey was carried out during the deriod of October 1, '84 to April 30, '85 covering 71 medical facilities in Chonnam Province. It was contested throughout the safety control radiation, radiation source control, radiation exposure, protective facility and image control. The results obtained are as follows; 1. What the medical facilities with x-ray units are handled by persons without licence, are 52.6% in Hospital level, 90.75% in Clinical level and 73% in Public Health center. 2. There are small tube capacity with less than tube current 100mA in 44.5% among the 157 x-ray units surveyed, and 25.4% in nonecollimators. 3. The x-ray room capacity is less than 10m2 is 38.8% in total surveyed medical institution. It is, therefore, not perfect in safety control, so it must be extensioned for prefer control. 4. The radiation shielding systems are perferable for satisfying in 22.5% and unsatisfied in 29.5%, respectively.. 5. There is no radiation exposure counter in medical facilities in 46.6%, even there is radiation exposure counter in 53.4%, though the counter are used in 35.2% only. 6. According to this survey, it is investigated that the regular data control for radiation exposure was not tested in 73.2%. Even though the radiotechnologist takes regular physical examination, the persons was tested by regular in 23.9%. 7. In case of chest indirect photoroentgraphy, the protective partitions are used in 55.9% and the lead apron are used in 15.25% only. 8. In case of daily x-ray checks, there are 87.3% inless than 100 cases, 12.7% in more than 100 case. 9. The medical facilities are checked regularly for the x-ray unit fuction in 16.9% only. 10. As the developing method, the automatic devices are 47.8% and the hand operates are 52.1%. Even though automatic system has, daily function was checked in regular 20.6% only. 11. In case of the intensifying screen, the medium speed intensifying screen is used in 28.1% and the high speed intensifying screen is used in 66.2%, reapectively. But there is only one hospital used the rare earth intensifying screen.
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LC 공진형 PWM 인버터를 이용한 X선 발생장치의 특성에 관한 연구
이성길,박수강,임홍우,조금배,백형래,임양수 조선대학교 에너지.자원신기술연구소 2002 에너지·자원신기술연구소 논문지 Vol.24 No.1
The conventional types of X-ray generators were bulky in physical size and heavy in weight, and the control accuracies of the output voltages were not always satisfactory. The high frequency switching inverter and converter technology on power conversion and control systems have been greatly closed up introducing power semiconductor devices. In this paper, the newly developed converter to take the balance of the output voltage versus the ground are also presented in detail to decreasing the volume and the weight of high voltage transformer and to stabilize ripple. This converter consists of the two independent L-C series resonant circuits using the two capacitances and the two primary windings of high voltage transformer.
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인버터식 X선 발생장치용 고압변압기의 특성개선에 관한 연구
이성길(Seong-Kil Lee),박수강(Su-Kang Park),이강연(Gang-Youn Lee),조금배(Geum-Bae Cho),백형래(Hyung-Lae Baek),임병옥(Byung-Ok Lim) 전력전자학회 2000 전력전자학술대회 논문집 Vol.2000 No.11
The conventional types of X-ray generators were bulky in physical size and heavy in weight, and the control accuracies of the output voltages were not always satisfactory The high frequency switching inverter and converter technology on power conversion and control systems have been greatly closed up introducing power semiconductor devices. To decreasing the volume and the weight of high voltage transformer, and to stabilize ripple.<br/> In this paper, the newly developed converter to take the balance of the output voltage versus the ground are also presented m detail. This converter consists of the two independent series resonant circuits using the two capacitances and the two primary windings of high-voltage transformer.
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이성길,김영근 광주보건대학 1998 論文集 Vol.23 No.-
Out Put Characteristic has been Investigated for Single, Three Phase and Inverter Type X-ray Generators. The results was following ; 1. The percent ripple of tube-voltage wave form appeared of low to 89. 8~96.6(%) in single phase, 7.3~10.5(%) in three phase generators and 3.5~4.7(%) in inverter type X-ray generators. 2. Rectification type are according to single phase, three phase and inverter type X-ray generators and out put efficients were different from 1 : 1.47 : 1.94. 3. HVL for measuring of X-ray quality increased orderly for single phase, three phase and inverter type X-ray generators. 4. Reproducibility of X-ray out put has done a very good in conversion factor of less than 0.05 for all equipments. 5. Linearity of X-ray out put appear to short exposure about inverter type generators for safety.
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이성길,김승국,박수강 광주보건대학 2003 論文集 Vol.28 No.-
The three-phase induction motor is rugged, reliable, long-lived, self-starting, smooth-running. But it is relatively inexpensive and three-phase power in not available everywhere, so if possible we need single-phase motor with the same characteristics. In fact, single-phase induction motors have excellent characteristics and outnumber the three-phase variety. Most of the small electric motors used in home, farm, or office are single-phase induction motors of one type or another. This electric motors application field need most energy saving type drive according to enlargement of electronic goods and to tend high class. The paper is proposed a various phase control methods for energy saving of single- phase induction motor. The controllers that are embodied by each method can use by various usage according to each performance and it is considered that application may help in the electrical energy saving because is possible to other electrical appliances.
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