The building of a large-scale external-target experiment, abbreviated as CEE, in the cooling storage ring at the Heavy Ion Research Facility in Lanzhou has been planned. The CEE is a multi-purpose spectrometer that wi...The building of a large-scale external-target experiment, abbreviated as CEE, in the cooling storage ring at the Heavy Ion Research Facility in Lanzhou has been planned. The CEE is a multi-purpose spectrometer that will be used for various studies on heavy-ion collisions. A multi-wire drift chamber(MWDC) array is the forward tracking detector of the CEE. In this work, GEANT4 simulations were performed for the MWDC forward tracking array with a focus on the track reconstruction algorithm. Combined with the time of flight information,particle identification is achieved. The residue is about 30 μm, while the tracking efficiency is higher than 90%with the current redundancy. In addition, a prototype of the forward tracking system using three MWDCs was assembled and tested using a high-energy proton beam. The firing efficiency of the detector and the reconstruction accuracy of the prototype were derived. The track residue for the protons at about 400 MeV/c is better than 300 μm, meeting the requirements of the CEE. Suggestions for improving the performance of the forward tracking system are given.展开更多
Based on the analysis of the mechanism of wire tension control by using torque motors in the multi-wire saw machining process, some mathematical models of a tension control system are studied, and an adaptive algo- ri...Based on the analysis of the mechanism of wire tension control by using torque motors in the multi-wire saw machining process, some mathematical models of a tension control system are studied, and an adaptive algo- rithm is designed for controlling the wire tension. In this algorithm of tension control, the rotation speeds and waving angle of motors are measured and fed back to the controller, and the NLMS（ normalized least mean squares） algorithm is used to calculate the adaptive correction value and control the wire tension accurately. The computer simulation results in Matlab software validate the high accuracy for controlling the system of the wire tension with the NLMS algorithm in the multi-wire saw machining process.展开更多
Background Failure of balloon catheter passing through the occluded segment accounts for 10%-15% of all procedures during percutaneous coronary intervention （PCI） for chronic total occlusion （CTO）. We sought to in...Background Failure of balloon catheter passing through the occluded segment accounts for 10%-15% of all procedures during percutaneous coronary intervention （PCI） for chronic total occlusion （CTO）. We sought to investigate an original technique for facilitating balloon catheter passing by multi-wire plaque crushing. Methods Between July 2000 and October 2007, 152 patients with 164 CTO lesions who had failed balloon passing were treated by multi-wire plaque crushing technique. The main process of this technique was to insert 1 or 2 wires along with the original wire located in the true lumen of CTO lesions after balloon failure for plaque crushing and then to withdraw the crushing wires to get an enlarged lumen inside of the occlusion segment, thus facilitating the balloon passing. Results Both overall lesion and technique success rates were 91.5% （150/164）. A total of 211 crushing wires were used during. PCI, including 1 crushing wire for 117 （71.3%） lesions and 2 crushing wires for 47 （28.7%） lesions. Approximately 57.3% （121/211） of all crushing wires were those already used in the same procedure. Technique failure occurred in 14 lesions （8.5%）. Technique failure was due to crushing wires entering false lumen （92.9%, 13/14） and coronary perforation （7.1%, 1/14）. Major procedural complications included coronary perforation （1 case） and severe coronary dissection （2 cases）, all of which were successfully treated. Conclusions Multi-wire plaque crushing technique is effective in facilitating balloon catheter passing during CTO PCI. It is feasible, economical and relatively safe with a low rate of procedural complications.展开更多
The design principle for a multi-wire proportional chamber with a cathode strip and delay-line readout is described. A prototype chamber of a size of 10 cm×10 cm was made together with the readout electronics cir...The design principle for a multi-wire proportional chamber with a cathode strip and delay-line readout is described. A prototype chamber of a size of 10 cm×10 cm was made together with the readout electronics circuit. A very clean signal with very low background noise was obtained by applying a transformer between the delay-line and the pre-amplifier in order to match the resistance. Along the anode wire direction a position resolution of less than 0.5 mm was achieved with a ^55Fe-5.9 keV X ray source. The simple structure, large effective area and high position resolution allow the application of a gas chamber of this kind to many purposes.展开更多
基金supported by the National Basic Research Program of China(973)(No.2015CB856903)the National Science Foundation of China(No.U1332207)
文摘The building of a large-scale external-target experiment, abbreviated as CEE, in the cooling storage ring at the Heavy Ion Research Facility in Lanzhou has been planned. The CEE is a multi-purpose spectrometer that will be used for various studies on heavy-ion collisions. A multi-wire drift chamber(MWDC) array is the forward tracking detector of the CEE. In this work, GEANT4 simulations were performed for the MWDC forward tracking array with a focus on the track reconstruction algorithm. Combined with the time of flight information,particle identification is achieved. The residue is about 30 μm, while the tracking efficiency is higher than 90%with the current redundancy. In addition, a prototype of the forward tracking system using three MWDCs was assembled and tested using a high-energy proton beam. The firing efficiency of the detector and the reconstruction accuracy of the prototype were derived. The track residue for the protons at about 400 MeV/c is better than 300 μm, meeting the requirements of the CEE. Suggestions for improving the performance of the forward tracking system are given.
基金supported by the National Natural Science Fundproject (50775207)Key Laboratory of E & M (Zhejiang University of Technology) Open Fund project (2009EP017)
文摘Based on the analysis of the mechanism of wire tension control by using torque motors in the multi-wire saw machining process, some mathematical models of a tension control system are studied, and an adaptive algo- rithm is designed for controlling the wire tension. In this algorithm of tension control, the rotation speeds and waving angle of motors are measured and fed back to the controller, and the NLMS（ normalized least mean squares） algorithm is used to calculate the adaptive correction value and control the wire tension accurately. The computer simulation results in Matlab software validate the high accuracy for controlling the system of the wire tension with the NLMS algorithm in the multi-wire saw machining process.
文摘Background Failure of balloon catheter passing through the occluded segment accounts for 10%-15% of all procedures during percutaneous coronary intervention （PCI） for chronic total occlusion （CTO）. We sought to investigate an original technique for facilitating balloon catheter passing by multi-wire plaque crushing. Methods Between July 2000 and October 2007, 152 patients with 164 CTO lesions who had failed balloon passing were treated by multi-wire plaque crushing technique. The main process of this technique was to insert 1 or 2 wires along with the original wire located in the true lumen of CTO lesions after balloon failure for plaque crushing and then to withdraw the crushing wires to get an enlarged lumen inside of the occlusion segment, thus facilitating the balloon passing. Results Both overall lesion and technique success rates were 91.5% （150/164）. A total of 211 crushing wires were used during. PCI, including 1 crushing wire for 117 （71.3%） lesions and 2 crushing wires for 47 （28.7%） lesions. Approximately 57.3% （121/211） of all crushing wires were those already used in the same procedure. Technique failure occurred in 14 lesions （8.5%）. Technique failure was due to crushing wires entering false lumen （92.9%, 13/14） and coronary perforation （7.1%, 1/14）. Major procedural complications included coronary perforation （1 case） and severe coronary dissection （2 cases）, all of which were successfully treated. Conclusions Multi-wire plaque crushing technique is effective in facilitating balloon catheter passing during CTO PCI. It is feasible, economical and relatively safe with a low rate of procedural complications.
基金Major State Basic Research Development Program of China (2007CB815002)NSFC (10775003, 10827505)
文摘The design principle for a multi-wire proportional chamber with a cathode strip and delay-line readout is described. A prototype chamber of a size of 10 cm×10 cm was made together with the readout electronics circuit. A very clean signal with very low background noise was obtained by applying a transformer between the delay-line and the pre-amplifier in order to match the resistance. Along the anode wire direction a position resolution of less than 0.5 mm was achieved with a ^55Fe-5.9 keV X ray source. The simple structure, large effective area and high position resolution allow the application of a gas chamber of this kind to many purposes.
