Ravi Shankar Narasimhan,executive editor of China Daily's overseas editions,was one of 70-plus foreign experts invited to the Great Hall of the People on January 21 for a symposium and a Chinese New Year dinner wi...Ravi Shankar Narasimhan,executive editor of China Daily's overseas editions,was one of 70-plus foreign experts invited to the Great Hall of the People on January 21 for a symposium and a Chinese New Year dinner with Premier Li Keqiang and senior State leaders.展开更多
A new Digital Pulse Processing（DPP） module has been developed, based on a domino ring sampler version 4 chip（DRS4）, with good time resolution for La Br3 detectors, and different digital timing analysis methods for...A new Digital Pulse Processing（DPP） module has been developed, based on a domino ring sampler version 4 chip（DRS4）, with good time resolution for La Br3 detectors, and different digital timing analysis methods for processing the raw detector signals are reported. The module, composed of an eight channel DRS4 chip, was used as the readout electronics and acquisition system to process the output signals from XP20D0 photomultiplier tubes（PMTs）. Two PMTs were coupled with La Br3 scintillators and placed on opposite sides of a radioactive positron22 Na source for 511 ke V γ-ray tests. By analyzing the raw data acquired by the module, the best coincidence timing resolution is about 194.7 ps（FWHM）, obtained by the digital constant fraction discrimination（d CFD） method,which is better than other digital methods and analysis methods based on conventional analog systems which have been tested. The results indicate that it is a promising approach to better localize the positron annihilation in positron emission tomography（PET） with time of flight（TOF）, as well as for scintillation timing measurement,such as in TOF-？E and TOF-E systems for particle identification, with picosecond accuracy timing measurement.Furthermore, this module is more simple and convenient than other systems.展开更多
Few hotels have captured as much attention before their opening as Mandarin Oriental, Beijing. Mandarin Oriental, Beijing has attracted extensive publicity for its spectacular appearance, and it also stands right besi...Few hotels have captured as much attention before their opening as Mandarin Oriental, Beijing. Mandarin Oriental, Beijing has attracted extensive publicity for its spectacular appearance, and it also stands right beside China Central Television’s (CCTV) breathtaking structure, with two tall .leaning towers joined by a horizontal section suspended in mid-air. The building has been described by Time magazine as an architectural wonder. The stunning pair of buildings advertise engineering excellence, avant-garde style and adventurous spirit.展开更多
文摘Ravi Shankar Narasimhan,executive editor of China Daily's overseas editions,was one of 70-plus foreign experts invited to the Great Hall of the People on January 21 for a symposium and a Chinese New Year dinner with Premier Li Keqiang and senior State leaders.
基金Supported by the Science Foundation of the Chinese Academy of Sciences(210340XBO)National Natural Science Foundation of China(11305233,11205222)+2 种基金General Program of National Natural Science Foundation of China(11475234)Specific Fund of National Key Scientific Instrument and Equipment Development Project(2011YQ12009604)Joint Fund for Research Based on Large-Scale Scientific Facilities(U1532131)
文摘A new Digital Pulse Processing（DPP） module has been developed, based on a domino ring sampler version 4 chip（DRS4）, with good time resolution for La Br3 detectors, and different digital timing analysis methods for processing the raw detector signals are reported. The module, composed of an eight channel DRS4 chip, was used as the readout electronics and acquisition system to process the output signals from XP20D0 photomultiplier tubes（PMTs）. Two PMTs were coupled with La Br3 scintillators and placed on opposite sides of a radioactive positron22 Na source for 511 ke V γ-ray tests. By analyzing the raw data acquired by the module, the best coincidence timing resolution is about 194.7 ps（FWHM）, obtained by the digital constant fraction discrimination（d CFD） method,which is better than other digital methods and analysis methods based on conventional analog systems which have been tested. The results indicate that it is a promising approach to better localize the positron annihilation in positron emission tomography（PET） with time of flight（TOF）, as well as for scintillation timing measurement,such as in TOF-？E and TOF-E systems for particle identification, with picosecond accuracy timing measurement.Furthermore, this module is more simple and convenient than other systems.
文摘Few hotels have captured as much attention before their opening as Mandarin Oriental, Beijing. Mandarin Oriental, Beijing has attracted extensive publicity for its spectacular appearance, and it also stands right beside China Central Television’s (CCTV) breathtaking structure, with two tall .leaning towers joined by a horizontal section suspended in mid-air. The building has been described by Time magazine as an architectural wonder. The stunning pair of buildings advertise engineering excellence, avant-garde style and adventurous spirit.
