A new combined soft switching technique and a novel topology of aeronautical static inverter with high frequency pulse dc link are proposed in this paper, namely an electrical isolated converter can realize soft swi...A new combined soft switching technique and a novel topology of aeronautical static inverter with high frequency pulse dc link are proposed in this paper, namely an electrical isolated converter can realize soft switching of two stage cascade converters. It lays technical foundation for high power density, high efficiency and low cost aeronautical static inverter. The operation and design approach of this topology are carefully analyzed and studied. The validity of this topology is verified by simulation and test.展开更多
Objective: To study the clinical significance of multi-slice spiral CT 3-dimensional (3D) portography in portal vein tumor thrombosis of hepatocellular cacinoma.Methods: 57 cases undergoing 3D portography were collect...Objective: To study the clinical significance of multi-slice spiral CT 3-dimensional (3D) portography in portal vein tumor thrombosis of hepatocellular cacinoma.Methods: 57 cases undergoing 3D portography were collected, of which 6 cases were normal, 5 cases were subjected to cirrhosis and hypertension of portal vein, 42 cases had portal tumor thrombus of hepatic cancer, and the remaining 4 cases showed lymph node enlargment in hilar of liver. All data of the patients came from conventional multi-slice spiral CT double phase of liver. Contrast media was 1.5–2 ml/kg with the injection rate being 2.5–3 ml/s. Axis and 3D portography was analyzed and compared in 42 cases of portal tumor thrombus of hepatic cancer.Results: According to portal tumor thrombus position, 42 cases were fallen into three categories: left (13 cases), right (20 cases), main (9 cases) of potal vein. There was no difference between axis and 3D portography in displaying portal tumor thrombus of hepatic cancer (P>0.05), but 3D portography showing collateral branches was better than axis portography after main portal vein thrombus.Conclusion: Multi-slice spiral CT 3D portography can display the position and types of portal tumor thrombus of hepatic cancer. 3D combined with axis portography can better evaluate the portal tumor thrombus of hepatic cancer and guide to select the therapies. Key words portal vein - tumor thrombus - multi-slice CT - 3 dimension imaging展开更多
Objective: To evaluate three-dimensional bronchial artery imaging charactersin central lung cancer and applied values with multi-slice spiral CT (MSCT) to provide theoreticalevidence on blood supply and intervention t...Objective: To evaluate three-dimensional bronchial artery imaging charactersin central lung cancer and applied values with multi-slice spiral CT (MSCT) to provide theoreticalevidence on blood supply and intervention therapy. Methods: Eighteen patients with central lungcancer underwent MSCT with real time helical thin-slice CT scanning. Three-dimensional bronchialartery reconstruction was done at the console work-station. The space anatomical characters ofbronchial artery were observed through different rotations. Results: For 6 cases, thethree-dimensional images of bronchial artery (33.33%) could exactly show the origins, the routes(lung inner segment and mediatism segment) and the diameters of bronchial arteries. Vision rate ofbronchial arteries was the highest in pulmonary artery stricture and truncation groups, and thevessels' diameter became larger apparently. These characters demonstrated blood supply of this kindof central lung cancer come from bronchial artery. Volume rendering images were the best ones amongthree-dimensional images. Conclusion: Three-dimensional imaging with MSCT in bronchial artery canreveal the anatomical characters of bronchial artery and provide theoretical evidence on bloodsupply and intervention therapy of central lung cancer.展开更多
A method for reconstructing 3-D motion of coronary arteries from single-plane X-ray angiogram sequences on two approximately orthogonal views is proposed. 2-D motion is firstly estimated separately along vascular cent...A method for reconstructing 3-D motion of coronary arteries from single-plane X-ray angiogram sequences on two approximately orthogonal views is proposed. 2-D motion is firstly estimated separately along vascular centerlines extracted from angiographic projection pairs. The 3-D displacement vector of each arterial skeleton point at one instant is then reconstructed by calculating the spatial coordinates of its two ends from corresponding projections. 3-D configuration and dynamics of arteries are finally characterized. The effectiveness of the algorithm has been demonstrated on vascular phantom images and clinical angiograms and results are encouraqing.展开更多
A method for mono-pulse radar 3-D imaging in stepped tracking mode is presented and the amplitude linear modulation of error signals in stepped tracking mode is analyzed with its compensation method followed, so the p...A method for mono-pulse radar 3-D imaging in stepped tracking mode is presented and the amplitude linear modulation of error signals in stepped tracking mode is analyzed with its compensation method followed, so the problem of precisely tracking of target is solved. Finally the validity of these methods is proven by the simulation results.展开更多
We study the existence of solutions to the second order three-point boundary value problem：{x″（t）＋f（t,x（t）,x′（t））=0,t≠ti,△x（ti）=Ii（x（ti）,x′（ti））,i=1,2,…,k,△x′（ti）=Ji（x（ti）,x′（t））,i=1...We study the existence of solutions to the second order three-point boundary value problem：{x″（t）＋f（t,x（t）,x′（t））=0,t≠ti,△x（ti）=Ii（x（ti）,x′（ti））,i=1,2,…,k,△x′（ti）=Ji（x（ti）,x′（t））,i=1,2,…,k,x（0）=0=x（1）-αx（η）,where 0〈η〈1,α∈R,and f：[0,1]×R×R→R,Ii：R×R→R,Ji：R×R→R（i=1,2,…,k）are continuous. Our results is new and different from previous results. In particular, we obtain the Green function of the problem, which makes the problem simpler.展开更多
Sixty-five new vibronic levels of the Na2 4^3∑g^＋ state have been observed in the 33900-35200 cm^-1 energy region above the potential minimum of the ground state by pulsed perturbation facilitated optical-optical do...Sixty-five new vibronic levels of the Na2 4^3∑g^＋ state have been observed in the 33900-35200 cm^-1 energy region above the potential minimum of the ground state by pulsed perturbation facilitated optical-optical double resonance （PFOODR） fluorescence excitation spectroscopy. These new data fill the gap between the low-v levels mainly observed by continuous wave （CW） PFOODR spectroscopy and the high-v levels above the 3s＋3d limit observed by pulsed PFOODR with predissociation detection, Molecular constants are fitted below potential shelf around the 3s＋3d atomic limit with previously published data （mainly observed by CW PFOODR） and these new data. RKR potential curve has been calculated with the new constants. The constants are： Te= 32127.090 cm^-1,ωe=121.4099（0.20720） cm^-1, Be = 0.116287（0.0002300） cm^-1, Re=3.551 A, An error of the RKR potential curve of J. Chem. Phys. 108, 7707 （1998） is corrected.展开更多
The new three-phase 5-level current-source inverter (CSI) proposed in this paper was developed by connecting three separate single-phase 5-level CSIs in series, and its operational principle was analyzed. There are tw...The new three-phase 5-level current-source inverter (CSI) proposed in this paper was developed by connecting three separate single-phase 5-level CSIs in series, and its operational principle was analyzed. There are two major problems existing in current-source multilevel inverters, one is the complex PWM control method (2-logic to 3-logic conversion), and the other is the problem of current-unbalance between different levels. A simple current-balance control method via DC current feedback is applied in each single-phase 5-level CSI cell to implement the current-balance control between different levels. And to reduce the output current harmonics, POD PWM control technique was used. Simulation and experimental results showed that this new three-phase 5-level CSI topology operates correctly.展开更多
Focused underwater plasma sound sources are being applied in more and more fields. Focusing performance is one of the most important factors determining transmission distance and peak values of the pulsed sound waves....Focused underwater plasma sound sources are being applied in more and more fields. Focusing performance is one of the most important factors determining transmission distance and peak values of the pulsed sound waves. The sound source’s components and focusing mechanism were all analyzed. A model was built in 3D Max and wave strength was measured on the simulation platform. Error analysis was fully integrated into the model so that effects on sound focusing performance of processing-errors and installation-errors could be studied. Based on what was practical, ways to limit the errors were proposed. The results of the error analysis should guide the design, machining, placement, debugging and application of underwater plasma sound sources.展开更多
In this paper it is reported for the first time that the third harmonic generated in EH32 mode of a gas-filled waveguide by fs pulses has higher generation efficiency. The new finding contrasts with the experiment in...In this paper it is reported for the first time that the third harmonic generated in EH32 mode of a gas-filled waveguide by fs pulses has higher generation efficiency. The new finding contrasts with the experiment in It. G. Durfee Ⅲ, S. Backus, M.M. Murnane, and H.C. Kapteyn, Opt. Left. 22 （1997） 1565]. Some possible factors, which produce the contradiction, are discussed briefly.展开更多
Gynura root has been used extensively in Chinese folk medicine and plays a role in promoting microcirculation and relieving pain.However,its hepatic toxicity should not be neglected.Recently,we admitted a 62-year old ...Gynura root has been used extensively in Chinese folk medicine and plays a role in promoting microcirculation and relieving pain.However,its hepatic toxicity should not be neglected.Recently,we admitted a 62-year old female who developed hepatic veno-occlusive disease(HVOD)after ingestion of Gynura root.Only a few articles on HVOD induced by Gynura root have been reported in the literature.It is suspected that pyrrolizidine alkaloids in Gynura root might be responsible for HVOD.In this paper,we report a case of HVOD and review the literature.展开更多
Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and ...Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and the sliding stability coefficient K 1 and the rotation stability coefficient K 2 are proposed to describe the stability of the triangle block structure quantitatively. The structure can keep a self stability before and after the roadway excavation, at the stage of mining induced effect, the stability of the structure is lowered, and the structure may become instability with decreasing the coal strength, increasing the mining height of working face and the mining depth.展开更多
In this paper, we propose a scheme for generating an arbitrary three-dimensional pure state of vibrational motion of a trapped ion. Our scheme is based on a sequence of laser pulses, which are tuned to the appropriate...In this paper, we propose a scheme for generating an arbitrary three-dimensional pure state of vibrational motion of a trapped ion. Our scheme is based on a sequence of laser pulses, which are tuned to the appropriate vibrational sidebands with respect to the appropriate electronic transition.展开更多
文摘A new combined soft switching technique and a novel topology of aeronautical static inverter with high frequency pulse dc link are proposed in this paper, namely an electrical isolated converter can realize soft switching of two stage cascade converters. It lays technical foundation for high power density, high efficiency and low cost aeronautical static inverter. The operation and design approach of this topology are carefully analyzed and studied. The validity of this topology is verified by simulation and test.
文摘Objective: To study the clinical significance of multi-slice spiral CT 3-dimensional (3D) portography in portal vein tumor thrombosis of hepatocellular cacinoma.Methods: 57 cases undergoing 3D portography were collected, of which 6 cases were normal, 5 cases were subjected to cirrhosis and hypertension of portal vein, 42 cases had portal tumor thrombus of hepatic cancer, and the remaining 4 cases showed lymph node enlargment in hilar of liver. All data of the patients came from conventional multi-slice spiral CT double phase of liver. Contrast media was 1.5–2 ml/kg with the injection rate being 2.5–3 ml/s. Axis and 3D portography was analyzed and compared in 42 cases of portal tumor thrombus of hepatic cancer.Results: According to portal tumor thrombus position, 42 cases were fallen into three categories: left (13 cases), right (20 cases), main (9 cases) of potal vein. There was no difference between axis and 3D portography in displaying portal tumor thrombus of hepatic cancer (P>0.05), but 3D portography showing collateral branches was better than axis portography after main portal vein thrombus.Conclusion: Multi-slice spiral CT 3D portography can display the position and types of portal tumor thrombus of hepatic cancer. 3D combined with axis portography can better evaluate the portal tumor thrombus of hepatic cancer and guide to select the therapies. Key words portal vein - tumor thrombus - multi-slice CT - 3 dimension imaging
文摘Objective: To evaluate three-dimensional bronchial artery imaging charactersin central lung cancer and applied values with multi-slice spiral CT (MSCT) to provide theoreticalevidence on blood supply and intervention therapy. Methods: Eighteen patients with central lungcancer underwent MSCT with real time helical thin-slice CT scanning. Three-dimensional bronchialartery reconstruction was done at the console work-station. The space anatomical characters ofbronchial artery were observed through different rotations. Results: For 6 cases, thethree-dimensional images of bronchial artery (33.33%) could exactly show the origins, the routes(lung inner segment and mediatism segment) and the diameters of bronchial arteries. Vision rate ofbronchial arteries was the highest in pulmonary artery stricture and truncation groups, and thevessels' diameter became larger apparently. These characters demonstrated blood supply of this kindof central lung cancer come from bronchial artery. Volume rendering images were the best ones amongthree-dimensional images. Conclusion: Three-dimensional imaging with MSCT in bronchial artery canreveal the anatomical characters of bronchial artery and provide theoretical evidence on bloodsupply and intervention therapy of central lung cancer.
基金Sponsored by Chinese Postdoctoral Foundation(2004036361)National Nature Science Foundation(30500129)
文摘A method for reconstructing 3-D motion of coronary arteries from single-plane X-ray angiogram sequences on two approximately orthogonal views is proposed. 2-D motion is firstly estimated separately along vascular centerlines extracted from angiographic projection pairs. The 3-D displacement vector of each arterial skeleton point at one instant is then reconstructed by calculating the spatial coordinates of its two ends from corresponding projections. 3-D configuration and dynamics of arteries are finally characterized. The effectiveness of the algorithm has been demonstrated on vascular phantom images and clinical angiograms and results are encouraqing.
文摘A method for mono-pulse radar 3-D imaging in stepped tracking mode is presented and the amplitude linear modulation of error signals in stepped tracking mode is analyzed with its compensation method followed, so the problem of precisely tracking of target is solved. Finally the validity of these methods is proven by the simulation results.
基金Supported by the National Natural Science Foundation of China(10371006)
文摘We study the existence of solutions to the second order three-point boundary value problem：{x″（t）＋f（t,x（t）,x′（t））=0,t≠ti,△x（ti）=Ii（x（ti）,x′（ti））,i=1,2,…,k,△x′（ti）=Ji（x（ti）,x′（t））,i=1,2,…,k,x（0）=0=x（1）-αx（η）,where 0〈η〈1,α∈R,and f：[0,1]×R×R→R,Ii：R×R→R,Ji：R×R→R（i=1,2,…,k）are continuous. Our results is new and different from previous results. In particular, we obtain the Green function of the problem, which makes the problem simpler.
基金This work was supported by the National Natural Science Foundation of China（NSFC No. 20473042, N0. 20173029 and 10174042）, NKBRSF, and SRFDP of China and by RFBR（grant 05-03-39012） of Russia.
文摘Sixty-five new vibronic levels of the Na2 4^3∑g^＋ state have been observed in the 33900-35200 cm^-1 energy region above the potential minimum of the ground state by pulsed perturbation facilitated optical-optical double resonance （PFOODR） fluorescence excitation spectroscopy. These new data fill the gap between the low-v levels mainly observed by continuous wave （CW） PFOODR spectroscopy and the high-v levels above the 3s＋3d limit observed by pulsed PFOODR with predissociation detection, Molecular constants are fitted below potential shelf around the 3s＋3d atomic limit with previously published data （mainly observed by CW PFOODR） and these new data. RKR potential curve has been calculated with the new constants. The constants are： Te= 32127.090 cm^-1,ωe=121.4099（0.20720） cm^-1, Be = 0.116287（0.0002300） cm^-1, Re=3.551 A, An error of the RKR potential curve of J. Chem. Phys. 108, 7707 （1998） is corrected.
基金Project (No. 50477033) supported by the National Natural Science Foundation of China
文摘The new three-phase 5-level current-source inverter (CSI) proposed in this paper was developed by connecting three separate single-phase 5-level CSIs in series, and its operational principle was analyzed. There are two major problems existing in current-source multilevel inverters, one is the complex PWM control method (2-logic to 3-logic conversion), and the other is the problem of current-unbalance between different levels. A simple current-balance control method via DC current feedback is applied in each single-phase 5-level CSI cell to implement the current-balance control between different levels. And to reduce the output current harmonics, POD PWM control technique was used. Simulation and experimental results showed that this new three-phase 5-level CSI topology operates correctly.
基金Supported by the National Natural Science Foundation under Grant No.60572098
文摘Focused underwater plasma sound sources are being applied in more and more fields. Focusing performance is one of the most important factors determining transmission distance and peak values of the pulsed sound waves. The sound source’s components and focusing mechanism were all analyzed. A model was built in 3D Max and wave strength was measured on the simulation platform. Error analysis was fully integrated into the model so that effects on sound focusing performance of processing-errors and installation-errors could be studied. Based on what was practical, ways to limit the errors were proposed. The results of the error analysis should guide the design, machining, placement, debugging and application of underwater plasma sound sources.
基金The project supported by National Natural Science Foundation of China under Grant No. 90103025 and the Research Fund for the Doctoral Program of Higher .Education of China under Grant No. 20020027006
文摘In this paper it is reported for the first time that the third harmonic generated in EH32 mode of a gas-filled waveguide by fs pulses has higher generation efficiency. The new finding contrasts with the experiment in It. G. Durfee Ⅲ, S. Backus, M.M. Murnane, and H.C. Kapteyn, Opt. Left. 22 （1997） 1565]. Some possible factors, which produce the contradiction, are discussed briefly.
文摘Gynura root has been used extensively in Chinese folk medicine and plays a role in promoting microcirculation and relieving pain.However,its hepatic toxicity should not be neglected.Recently,we admitted a 62-year old female who developed hepatic veno-occlusive disease(HVOD)after ingestion of Gynura root.Only a few articles on HVOD induced by Gynura root have been reported in the literature.It is suspected that pyrrolizidine alkaloids in Gynura root might be responsible for HVOD.In this paper,we report a case of HVOD and review the literature.
文摘Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and the sliding stability coefficient K 1 and the rotation stability coefficient K 2 are proposed to describe the stability of the triangle block structure quantitatively. The structure can keep a self stability before and after the roadway excavation, at the stage of mining induced effect, the stability of the structure is lowered, and the structure may become instability with decreasing the coal strength, increasing the mining height of working face and the mining depth.
基金Supported by Key Program of National Natural Science Foundation of China under Grant No. 60931002National Natural Science Foundation of China under Grant No.10704001+3 种基金Anhui Provincial Natural Science Foundation under Grant No. 070412060the Major Program of the Education Department of Anhui Province under Grant No. KJ2010ZD08the Key Program of the Education Department of Anhui Province under Grant No. KJ2010A287the Personal Development Foundation of Anhui Province under Grant No. 2009Z022
文摘In this paper, we propose a scheme for generating an arbitrary three-dimensional pure state of vibrational motion of a trapped ion. Our scheme is based on a sequence of laser pulses, which are tuned to the appropriate vibrational sidebands with respect to the appropriate electronic transition.
