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THD 감소를 위한 단상공간벡터 변조방식의 정류기 설계
임양수,이영식 서강정보대학 1999 산업과학연구 Vol.1 No.-
A single-phase PWM current source rectifier with a neutral leg is presented and throughly analyzed in this paper. This novel topology is implemented by adding an extra leg a step-down single phase PWM space vector modulation method to reduce the dc output voltage harmonics. The PWM pattern generation need a digital system. As compared with a conventional single-phase PWM rectifier, over 20% improvement of the total harmonics distortion in the output voltage can be obtained. Different SVM techniques are analyzed for this PWM rectifier and simulation results are presented.
보조권선 전압제어에 의한 단상유도전동기 기동특성에 관한 연구
임양수 서강정보대학 1996 論文集 Vol.15 No.-
The most common starting method of the single phase induction motor(SPIM) is to install a starting condenser and a centrifugal switch in series with the auxiliary winding. This method is simple but life of the SPIM is short, efficiency improvement has limitation because of the malfunction of the starting condenser and the centrifugal switch. In the general, starting characteristics of the single phase induction motor is accomplished by the amplitude voltage and phase angle difference between main and auxiliary winding. In the reason, the applied voltage amplitude of the single phase induction motor is controlled for improvement starting performence characteristics. In this paper, the starting characteristics of the SPIM is improved by voltage control strategy of auxiliary winding. Finally, the excellent starting performance and characteristics of the SPIM are shown through simulation and experimental results.
임양수 서강대학 지역발전연구소 1997 지역발전연구 : 서강전문대 Vol.4 No.1
Single phase induction motors(SPIM's) have been widely used in applications of light duty such as washing machines, oil burners, bottle washers, blowers, grinders, machine tools, and a host of other applications. SPIM' s are inherently suitable for single phase power supplies, very simple in structure and rugged, of which rotor structure is generally squirrel cage rotor similar to polyphase induction motors. The SPIM can not start as such motors but once start in a given direction by mechanical switch it can approach nearly synchronous speed on condition that the load torque is not excessive. The capacitor starting method has been widely used to start SPIM for producing a dominant rotating magnetic field at standstill. To overcome the lack of sufficient starting torque, capacitor starting SPIM is provided both capacitor and centrifugal switch in series with the auxiliary winding circuit. A new method to start smoothingly a single phase induction motor by using a TRIAC is presented in this paper without the centrifugal switch. Solid state soft starters based on TRIAC's often used to decrease the starting current of the three phase motors. However, Even today, the capacitor-start single phase induction motor using centrifugal or relay switch is one of the most important and most widely used of all the types of single phase motors. In this paper, single phase induction motor input current was detected by a small current transformer. The soft start strategy is based on limited auxiliary current angle during starting period in the closed loop control. Simulation and experimental results of the SPIM using the TRIAC control are studied and discussed in the aspects of starting characteristics of the SPIM.
유방암에서 CEA, CA15-3 및 TPS의 예후인자로서의 가치
임양수,정진향,박호용,이영하,고창대 대한외과학회 2007 Annals of Surgical Treatment and Research(ASRT) Vol.73 No.1
Purpose: Tumor markers are often used to monitor the response to therapy and to detect recurrences in patients with resected breast cancer. Here we evaluated the prognostic value of the preoperative serum concentrations of tumor markers in patients with breast cancer. Methods: The preoperative serum concentrations of tumor markers (CEA, CA15-3 and TPS) were measured in 670 patients who were treated via potentially curative surgical resection for breast cancer from 2001 to 2004. We investigated the association of the serum concentrations of tumor markers with the disease-free survival and overall survival at the time of the primary diagnosis in relation to the established prognostic factors such as tumor size, lymph node status, hormonal receptor status, age and menopausal status. Results: The established prognostic factors and the elevated preoperative serum tumor marker values were correlated with disease-free survival (CEA: P=0.014, CA15-3: P=0.002 and TPS: P<0.001) and overall survival (CEA: P=0.045, CA15-3: P=0.002 and TPS: P<0.001) on univariate analysis. On multivariate analysis, tumor size, lymph node status, hormone receptor status and TPS (P=0.03) were independent prognostic factors for recurrence and the lymph node status, hormone receptor status and TPS serum level (P<0.001) were independent prognostic factors for overall survival. Conclusion: The preoperative serum concentrations of tumor makers (CEA, CA15-3 and TPS) are strong independent prognostic factors for recurrence and survival in patients with breast cancer. The tests for the preoperativeserum concentrations of tumor markers have convenient and reproducible advantages while the others require tumor tissue. Patients with elevated preoperative serum tumor marker values need appropriate adjuvant therapy, careful monitoring and detection of recurrences during the follow-up period. (J Korean Surg Soc 2007;73:21-26)
임형수(Hyung Soo Lim),임영천(Young Cheon Lim),송성진(Seung Jin Song),강신형(Shin Hyoung Kang),양수석(Soo Seok Yang) 한국유체기계학회 2009 유체기계 연구개발 발표회 논문집 Vol.2009 No.-
In this research, experimental investigation has been observed to enhance 4 stage axial compressor stability by steady air injection. By injecting air in front of 1st stage rotor tip, compressor operation range was extended about 4% based on no injection condition. The stall onset stage, signal frequency and stall cell feature were analyzed and these characters were compared with no injection condition's. Even though, no significant different was detected in steady air injection, except stall onset performance point, this results can be used as a reference for selecting injection stages in multistage compressor.