Based on the inertial navigation system, the influences of the excursion of the inertial navigation system and the measurement error of the wireless pressure altimeter on the rotation and scale of the real image are q...Based on the inertial navigation system, the influences of the excursion of the inertial navigation system and the measurement error of the wireless pressure altimeter on the rotation and scale of the real image are quantitatively analyzed in scene matching. The log-polar transform （LPT） is utilized and an anti-rotation and anti- scale image matching algorithm is proposed based on the image edge feature point extraction. In the algorithm, the center point is combined with its four-neighbor points, and the corresponding computing process is put forward. Simulation results show that in the image rotation and scale variation range resulted from the navigation system error and the measurement error of the wireless pressure altimeter, the proposed image matching algo- rithm can satisfy the accuracy demands of the scene aided navigation system and provide the location error-correcting information of the system.展开更多
A precision centrifuge is an inertial navigation test equipment used for calibrating the characteristics of accelerometers with high overloading, and a two axis centrifuge can be used to generate either constant accel...A precision centrifuge is an inertial navigation test equipment used for calibrating the characteristics of accelerometers with high overloading, and a two axis centrifuge can be used to generate either constant acceleration or harmonic acceleration. The moving trajectory equation about the origin of the accelerometer coordinate system in a two axis centrifuge was directly deduced through homogeneous transformation. The acceleration vector of the origin in accelerometer coordinate system was achieved by making the second derivative of this trajectory equation. The acceleration components were acquired by decomposing this acceleration vector along the three axes of the accelerometer coordinate system. The correctness of the homogeneous transformation was verified through vector analysis.展开更多
The effects of toughener and coupling agent on special epoxy silicone adhesive were discussed by researching the surface morphology characters, thermal properties and shear strength of the adhesive. The results indica...The effects of toughener and coupling agent on special epoxy silicone adhesive were discussed by researching the surface morphology characters, thermal properties and shear strength of the adhesive. The results indicate that silicone coupling agent (KH-550) can improve the shear strength of the epoxy silicone adhesive effectively. The mass fraction of the toughener in the epoxy silicone adhesive plays an important role in its properties. When the mass fraction of the toughener is less than 14%, the shear strength of the adhesive is low. When the mass fraction of the toughener is over 33%, thermal properties and shear strength of the adhesive decrease with the increasing of the toughener. The mass fraction of toughener of 25% results in good integral properties of the epoxy silicone adhesive. The morphologic analysis indicates that the micro-phase separation exists in the epoxy molecular chain and the silicone molecular chain of the epoxy silicone adhesive.展开更多
A new model of roving frame FA467, which uses four frequency inverters to replace the complex mechanical transmission, is discussed. A Neuron-PID is designed to reduce the effect of various parametric variations such ...A new model of roving frame FA467, which uses four frequency inverters to replace the complex mechanical transmission, is discussed. A Neuron-PID is designed to reduce the effect of various parametric variations such as load inertia. To ensure the constant spinning tension all over the spinning process, a feedforward controller using iterative learning control algorithm is desigend to avoid disturbances caused by changes of temperature, humidity and so on. The simulation result is shown to illustrate the effectiveness of the proposed algorithm, and now the roving frame FA467 has been developed successfully.展开更多
The food habits hypothesis （FHH） stands as one of the most striking and often-cited interspecific patterns to emerge from comparative studies of endothermic energetics. The FHH identifies three components of diet th...The food habits hypothesis （FHH） stands as one of the most striking and often-cited interspecific patterns to emerge from comparative studies of endothermic energetics. The FHH identifies three components of diet that potentially produce variability in mass-independent BMR, i.e. food quality, food availability, and food predictability or environmental productivity. The hypothesis predicts that species with diets of low energy content and/or low digestibility should evolve low mass-independent BMRs. The effects of food habits on BMR have been widely investigated at the interspecific level, but the variation between individuals and populations has been largely ignored. Our focus is to compare predictions derived from interspecific studies with data collected from within-species studies to explore the mechanisms and functional significance of adaptive responses predicted by the food-habits hypothesis among birds. We conclude that if BMR is correlated with daily energy expenditure, then organisms that can lower BMR will reduce daily energy expenditure and hence, food requirements. Birds that lower BMR in stressful environments may increase survival. Nevertheless, the mechanism （s） by which birds eating a low quality diet reduce BMR and whether lower BMR affects fitness remain to be determined [Current Zoology 56 （6）： 759-766, 2010].展开更多
In order to solve the problem of weak power performance of vehicle equipped with continuously variable transmission(CVT) system working under transient operating conditions, a new CVT equipped with planetary gear mech...In order to solve the problem of weak power performance of vehicle equipped with continuously variable transmission(CVT) system working under transient operating conditions, a new CVT equipped with planetary gear mechanism and flywheel was researched, a design method of transmission parameter optimization was proposed, and the comprehensive matching control strategy was established for the new transmission system. Fuzzy controllers for throttle opening and CVT speed ratio were designed, and power performance and fuel economy of both vehicles respectively equipped with conventional CVT system and new transmission system wrere compared and analyzed by simulation. The results show that power performance and fuel economy of the vehicle equipped with new transmission system are better than that equipped with conventional CVT, thus the rationality of the parameter design method and control algorithm are verified.展开更多
We determine the dependence of key inertial confinement fusion （ICF） hot spot properties on the deuterium-tritium （DT） fuel adiabat accomplished by addition of heat to the cold shell. Our main result is to observe...We determine the dependence of key inertial confinement fusion （ICF） hot spot properties on the deuterium-tritium （DT） fuel adiabat accomplished by addition of heat to the cold shell. Our main result is to observe that variation of this parameter reduces the simulation to experiment discrepancy in several experimentally inferred quantities. Simulations are continued from capsule only l D simulations using the Lawrence Livermore National Laboratory ICF code, HYDRA. The continuations employ the high energy density physics （HEDP） University of Chicago code, FLASH, and a hydro only code, FronTier, modified with a radiation equation of state （EOS） model. Hot spot densities, burn-weighted ion temperatures and pressures show a decreasing trend, while the hot spot radius shows an increasing trend in response to added heat to the cold shell. Instantaneous quantities are assessed at the time of maximum neutron production within each simulation.展开更多
Calculated results of inertia moment of turbo-generator rotor can be quite different by methods used in load rejection tests. In view of fluctuation features of rotor speed rise curve during load rejection tests, the ...Calculated results of inertia moment of turbo-generator rotor can be quite different by methods used in load rejection tests. In view of fluctuation features of rotor speed rise curve during load rejection tests, the measurement principle of rotor inertia moment was expounded. Based on the measured data in load rejection tests for an imported type of domestic 300-MW generating unit, the rotor speed rise curve was fitted with three kinds of functions to get initial runup rate, but the obtained results differed a lot from each other. According to analysis on the mechanism of rotor speed rise, m=2 consecutive points averaging or FFT (Fast Fourier Transform) smoothing technology was introduced to process test data, and then the initial runup rate was determined by the method of linear fitting of rotor speed in the range of governing valve closing time. Although the obtained curves had a fluctuating shape, the results of rotor inertia moment for 50% and 100% load rejection tests were of good consistency.展开更多
文摘Based on the inertial navigation system, the influences of the excursion of the inertial navigation system and the measurement error of the wireless pressure altimeter on the rotation and scale of the real image are quantitatively analyzed in scene matching. The log-polar transform （LPT） is utilized and an anti-rotation and anti- scale image matching algorithm is proposed based on the image edge feature point extraction. In the algorithm, the center point is combined with its four-neighbor points, and the corresponding computing process is put forward. Simulation results show that in the image rotation and scale variation range resulted from the navigation system error and the measurement error of the wireless pressure altimeter, the proposed image matching algo- rithm can satisfy the accuracy demands of the scene aided navigation system and provide the location error-correcting information of the system.
文摘A precision centrifuge is an inertial navigation test equipment used for calibrating the characteristics of accelerometers with high overloading, and a two axis centrifuge can be used to generate either constant acceleration or harmonic acceleration. The moving trajectory equation about the origin of the accelerometer coordinate system in a two axis centrifuge was directly deduced through homogeneous transformation. The acceleration vector of the origin in accelerometer coordinate system was achieved by making the second derivative of this trajectory equation. The acceleration components were acquired by decomposing this acceleration vector along the three axes of the accelerometer coordinate system. The correctness of the homogeneous transformation was verified through vector analysis.
基金Project supported by the National High-Tech Research and Development Program of China
文摘The effects of toughener and coupling agent on special epoxy silicone adhesive were discussed by researching the surface morphology characters, thermal properties and shear strength of the adhesive. The results indicate that silicone coupling agent (KH-550) can improve the shear strength of the epoxy silicone adhesive effectively. The mass fraction of the toughener in the epoxy silicone adhesive plays an important role in its properties. When the mass fraction of the toughener is less than 14%, the shear strength of the adhesive is low. When the mass fraction of the toughener is over 33%, thermal properties and shear strength of the adhesive decrease with the increasing of the toughener. The mass fraction of toughener of 25% results in good integral properties of the epoxy silicone adhesive. The morphologic analysis indicates that the micro-phase separation exists in the epoxy molecular chain and the silicone molecular chain of the epoxy silicone adhesive.
文摘A new model of roving frame FA467, which uses four frequency inverters to replace the complex mechanical transmission, is discussed. A Neuron-PID is designed to reduce the effect of various parametric variations such as load inertia. To ensure the constant spinning tension all over the spinning process, a feedforward controller using iterative learning control algorithm is desigend to avoid disturbances caused by changes of temperature, humidity and so on. The simulation result is shown to illustrate the effectiveness of the proposed algorithm, and now the roving frame FA467 has been developed successfully.
文摘The food habits hypothesis （FHH） stands as one of the most striking and often-cited interspecific patterns to emerge from comparative studies of endothermic energetics. The FHH identifies three components of diet that potentially produce variability in mass-independent BMR, i.e. food quality, food availability, and food predictability or environmental productivity. The hypothesis predicts that species with diets of low energy content and/or low digestibility should evolve low mass-independent BMRs. The effects of food habits on BMR have been widely investigated at the interspecific level, but the variation between individuals and populations has been largely ignored. Our focus is to compare predictions derived from interspecific studies with data collected from within-species studies to explore the mechanisms and functional significance of adaptive responses predicted by the food-habits hypothesis among birds. We conclude that if BMR is correlated with daily energy expenditure, then organisms that can lower BMR will reduce daily energy expenditure and hence, food requirements. Birds that lower BMR in stressful environments may increase survival. Nevertheless, the mechanism （s） by which birds eating a low quality diet reduce BMR and whether lower BMR affects fitness remain to be determined [Current Zoology 56 （6）： 759-766, 2010].
基金Project(2011BA3019)supported by the Chongqing Natural Science Foundation,China
文摘In order to solve the problem of weak power performance of vehicle equipped with continuously variable transmission(CVT) system working under transient operating conditions, a new CVT equipped with planetary gear mechanism and flywheel was researched, a design method of transmission parameter optimization was proposed, and the comprehensive matching control strategy was established for the new transmission system. Fuzzy controllers for throttle opening and CVT speed ratio were designed, and power performance and fuel economy of both vehicles respectively equipped with conventional CVT system and new transmission system wrere compared and analyzed by simulation. The results show that power performance and fuel economy of the vehicle equipped with new transmission system are better than that equipped with conventional CVT, thus the rationality of the parameter design method and control algorithm are verified.
文摘We determine the dependence of key inertial confinement fusion （ICF） hot spot properties on the deuterium-tritium （DT） fuel adiabat accomplished by addition of heat to the cold shell. Our main result is to observe that variation of this parameter reduces the simulation to experiment discrepancy in several experimentally inferred quantities. Simulations are continued from capsule only l D simulations using the Lawrence Livermore National Laboratory ICF code, HYDRA. The continuations employ the high energy density physics （HEDP） University of Chicago code, FLASH, and a hydro only code, FronTier, modified with a radiation equation of state （EOS） model. Hot spot densities, burn-weighted ion temperatures and pressures show a decreasing trend, while the hot spot radius shows an increasing trend in response to added heat to the cold shell. Instantaneous quantities are assessed at the time of maximum neutron production within each simulation.
文摘Calculated results of inertia moment of turbo-generator rotor can be quite different by methods used in load rejection tests. In view of fluctuation features of rotor speed rise curve during load rejection tests, the measurement principle of rotor inertia moment was expounded. Based on the measured data in load rejection tests for an imported type of domestic 300-MW generating unit, the rotor speed rise curve was fitted with three kinds of functions to get initial runup rate, but the obtained results differed a lot from each other. According to analysis on the mechanism of rotor speed rise, m=2 consecutive points averaging or FFT (Fast Fourier Transform) smoothing technology was introduced to process test data, and then the initial runup rate was determined by the method of linear fitting of rotor speed in the range of governing valve closing time. Although the obtained curves had a fluctuating shape, the results of rotor inertia moment for 50% and 100% load rejection tests were of good consistency.
