In advanced nuclear fuel design, the outer strap of a spacer grid plays an important role on fuel assembly mechanical and thermal-hydraulic performance, e.g., precluding the risk of hang-up and improvement on the mixi...In advanced nuclear fuel design, the outer strap of a spacer grid plays an important role on fuel assembly mechanical and thermal-hydraulic performance, e.g., precluding the risk of hang-up and improvement on the mixing of the coolant. The communication of the outer strap affects the hydraulic force exerted by the spacer grid of the fuel assembly which could induce fuel assembly bow. In present study, in order to understand the influencing factors of hydraulic force exerted by the spacer grid, outer straps with various flow opening design features, different location and size are investigated by a commercially CFD （computational fluid dynamics） code, ANSYS CFX 12.1. Three dimensional rod bundles including the outer strap without and with different openings are modelled for simulation. The analysis results show that the openings on the spacer grid outer strap can reduce the lateral hydraulic loadings perpendicular to the centerline of the fuel rods exerted by the spacer grids obviously because of the pressures inside and outside the spacer grids being balanced. Besides, influences of the opening design features on the hydraulic force, resistance characteristics and lateral flow factor are investigated in details.展开更多
The laser gyro is most su it able for building the strap down inertial navigation system (SINS), and its acc uracy of attitude algorithm can enormously affect that of the laser SINS. This p aper develops three improv...The laser gyro is most su it able for building the strap down inertial navigation system (SINS), and its acc uracy of attitude algorithm can enormously affect that of the laser SINS. This p aper develops three improved algorithmal expressions for strap down attitude ut ilizing the angular increment output by the laser gyro from the last two and cur rent updating periods according to the number of gyro samples, and analyses the algorithm error in the classical coning motion. Compared with the conventional algorithms, simulational results show that this improved algorithm has higher precision. A new way to improve the rotation vector algorithms is provided.展开更多
A new loop and fold wave-guide ion cyclotron resonance frequency （ICRF） antenna with a power output of 3 MW, which can operate at a frequency in the range of 30 MHz to 110 MHz, was designed. The design of key compon...A new loop and fold wave-guide ion cyclotron resonance frequency （ICRF） antenna with a power output of 3 MW, which can operate at a frequency in the range of 30 MHz to 110 MHz, was designed. The design of key components of the new ICRF antenna and the charac- ters of the new,.]~rototype ICRF antenna are presented. The thermo-mechanical analysis of both the Faraday shield and the current straps was conducted, and the stresses due to heat loads are studied in detail with different cooling-water velocities considered. In addition, the movability of prototype ICRF antenna under vacuum condition by the driving system was tested. An engineer- ing commissioning was successfully performed on the prototype ICRF antenna using the original transmitter. The results are close to the expected.展开更多
Paper products such as corrugated paperboards are the most common green packaging materials, which are renewable, sustainable, recyclable and biodegradable. However, the plastic or metal straps used to secure the cart...Paper products such as corrugated paperboards are the most common green packaging materials, which are renewable, sustainable, recyclable and biodegradable. However, the plastic or metal straps used to secure the carton boxes are not so green. At the end of packaging, the carton boxes can be recycled, but the plastic/metal straps have to be sorted out for disposal separately. This review focuses on: 1) the global trend of green packaging;2) conventional plastic/metal strapping materials for carton boxes;3) conventional market pulp baling with steel wire as the tying materials;4) cellulose fiber-based materials for strapping market pulp bales and carton boxes. New generation of cellulose paper straps are being developed for more challenging applications with superior strength properties and repulpability.展开更多
The LM-3C/Yuanzheng 1 launch vehicle lifted off from the Xichang Satellite Launch Center at 21:52 Beijing time on March 30,2015,putting China’s 17th Bei Dou satellite into orbit.At 03:34 on March 31,the satellite det...The LM-3C/Yuanzheng 1 launch vehicle lifted off from the Xichang Satellite Launch Center at 21:52 Beijing time on March 30,2015,putting China’s 17th Bei Dou satellite into orbit.At 03:34 on March 31,the satellite detached from the Yuanzheng 1 upper stage and entered its working orbit directly,marking the success of China’s first launch mission in year 2015.The China Academy of Launch展开更多
THE Curtain of the stage wasin the manner of a hugetraditional Chinese painting,recounting some long-forgotten tra-gedy with its bright colors and vividstrokes.When the curtain lifted,agorgeous bridal sedan chair, acc...THE Curtain of the stage wasin the manner of a hugetraditional Chinese painting,recounting some long-forgotten tra-gedy with its bright colors and vividstrokes.When the curtain lifted,agorgeous bridal sedan chair, accom-panied by a procession bedeckedwith flags,was carried onto thestage to the accompaniment of fire-crackers,drums and gongs.The fairand docile Liu Siniang was about tobe betrothed to the brave and strap-ping Fu Xiang.展开更多
The LM-2E,a large strap-onlaunch vehicle developed by China,represents a major achievement ofthe country in space launch technol-ogy.Many key technologies,in-cluding structural dynamics,aero-dynamics and large payload...The LM-2E,a large strap-onlaunch vehicle developed by China,represents a major achievement ofthe country in space launch technol-ogy.Many key technologies,in-cluding structural dynamics,aero-dynamics and large payload fair-ing,had been developed and usedin the LM-2E.The large capabilityand high reliability of the vehiclewere verified by the successful testflight in 1990 and the launches oftwo Aussat B communications satel-lites made by Hughes in the UnitedStates.China has been展开更多
文摘In advanced nuclear fuel design, the outer strap of a spacer grid plays an important role on fuel assembly mechanical and thermal-hydraulic performance, e.g., precluding the risk of hang-up and improvement on the mixing of the coolant. The communication of the outer strap affects the hydraulic force exerted by the spacer grid of the fuel assembly which could induce fuel assembly bow. In present study, in order to understand the influencing factors of hydraulic force exerted by the spacer grid, outer straps with various flow opening design features, different location and size are investigated by a commercially CFD （computational fluid dynamics） code, ANSYS CFX 12.1. Three dimensional rod bundles including the outer strap without and with different openings are modelled for simulation. The analysis results show that the openings on the spacer grid outer strap can reduce the lateral hydraulic loadings perpendicular to the centerline of the fuel rods exerted by the spacer grids obviously because of the pressures inside and outside the spacer grids being balanced. Besides, influences of the opening design features on the hydraulic force, resistance characteristics and lateral flow factor are investigated in details.
文摘The laser gyro is most su it able for building the strap down inertial navigation system (SINS), and its acc uracy of attitude algorithm can enormously affect that of the laser SINS. This p aper develops three improved algorithmal expressions for strap down attitude ut ilizing the angular increment output by the laser gyro from the last two and cur rent updating periods according to the number of gyro samples, and analyses the algorithm error in the classical coning motion. Compared with the conventional algorithms, simulational results show that this improved algorithm has higher precision. A new way to improve the rotation vector algorithms is provided.
文摘A new loop and fold wave-guide ion cyclotron resonance frequency （ICRF） antenna with a power output of 3 MW, which can operate at a frequency in the range of 30 MHz to 110 MHz, was designed. The design of key components of the new ICRF antenna and the charac- ters of the new,.]~rototype ICRF antenna are presented. The thermo-mechanical analysis of both the Faraday shield and the current straps was conducted, and the stresses due to heat loads are studied in detail with different cooling-water velocities considered. In addition, the movability of prototype ICRF antenna under vacuum condition by the driving system was tested. An engineer- ing commissioning was successfully performed on the prototype ICRF antenna using the original transmitter. The results are close to the expected.
文摘Paper products such as corrugated paperboards are the most common green packaging materials, which are renewable, sustainable, recyclable and biodegradable. However, the plastic or metal straps used to secure the carton boxes are not so green. At the end of packaging, the carton boxes can be recycled, but the plastic/metal straps have to be sorted out for disposal separately. This review focuses on: 1) the global trend of green packaging;2) conventional plastic/metal strapping materials for carton boxes;3) conventional market pulp baling with steel wire as the tying materials;4) cellulose fiber-based materials for strapping market pulp bales and carton boxes. New generation of cellulose paper straps are being developed for more challenging applications with superior strength properties and repulpability.
文摘The LM-3C/Yuanzheng 1 launch vehicle lifted off from the Xichang Satellite Launch Center at 21:52 Beijing time on March 30,2015,putting China’s 17th Bei Dou satellite into orbit.At 03:34 on March 31,the satellite detached from the Yuanzheng 1 upper stage and entered its working orbit directly,marking the success of China’s first launch mission in year 2015.The China Academy of Launch
文摘THE Curtain of the stage wasin the manner of a hugetraditional Chinese painting,recounting some long-forgotten tra-gedy with its bright colors and vividstrokes.When the curtain lifted,agorgeous bridal sedan chair, accom-panied by a procession bedeckedwith flags,was carried onto thestage to the accompaniment of fire-crackers,drums and gongs.The fairand docile Liu Siniang was about tobe betrothed to the brave and strap-ping Fu Xiang.
文摘The LM-2E,a large strap-onlaunch vehicle developed by China,represents a major achievement ofthe country in space launch technol-ogy.Many key technologies,in-cluding structural dynamics,aero-dynamics and large payload fair-ing,had been developed and usedin the LM-2E.The large capabilityand high reliability of the vehiclewere verified by the successful testflight in 1990 and the launches oftwo Aussat B communications satel-lites made by Hughes in the UnitedStates.China has been
