Based on the numerical simulation analysis, structure parameters of the high pressure fuel pump and common rail as well as flow limiter are designed and the GD-1 high pressure common rail fuel injection system is self...Based on the numerical simulation analysis, structure parameters of the high pressure fuel pump and common rail as well as flow limiter are designed and the GD-1 high pressure common rail fuel injection system is self-developed. Fuel injection characteristics experiment is performed on the GD-1 system. And double-factor variance analysis is applied to investigate the influence of the rail pressure and injection pulse width on the consistency of fuel injection quantity, thus to test whether the design of structure parameters is sound accordingly. The results of experiment and test show that rail pressure and injection pulse width as well as their mutual-effect have no influence on the injection quantity consistency, which proves that the structure parameters design is successful and performance of GD-1 system is sound.展开更多
The spatial distribution of physico-chemical parameters(sea surface temperature(SST), p H, sea surface salinity(SSS), dissolved oxygen(DO) and Secchi depth) along with filterable nutrients(dissolved inorganic...The spatial distribution of physico-chemical parameters(sea surface temperature(SST), p H, sea surface salinity(SSS), dissolved oxygen(DO) and Secchi depth) along with filterable nutrients(dissolved inorganic nitrate(DIN),dissolved inorganic phosphate(DIP) and reactive silicate(DSi)) are measured in the winter months of November,December, January and February for four consecutive years from 2009–2010 to 2012–2013 on the shallow continental shelf(〈20 m bathymetry) of the coastal waters(up to 18 km away from shoreline) of the northern Bay of Bengal(n Bo B) during the highest high tide(HHT) and lowest low tide(LLT) hours for the first time. The variability of the coastal biogeochemical environment is assessed during the HHT and LLT hours and for this purpose, seawater samples are collected from seven different locations of a transect in the coastal region. Physicochemical parameters(except SST) show significant difference in magnitude during the HHT and LLT hours respectively. p H, SSS and DO are found to increase in the HHT hours and vice-versa. The data reveal that during the LLT hours, a relative increase of freshwater input in the n Bo B can have elevated the nutrient concentration compared with that observed during the HHT hours. The ratio of nutrient concentration is found to deviate significantly from the Redfield ratio. The abundance of DIP is much higher compared with that of DIN and DSi.The anthropogenic sources of DIP from the upstream flow(especially the domestic effluent of several metropolises) can be mainly attributed behind such an observation. In order to characterize and establish the trend of such variation in such an important bio-climatic region, long-term and systematic ecosystem monitoring in the coastal water of the n Bo B northern Bay of Bengal should be carried out throughout the year.展开更多
This paper focuses on synthesizing a mixed robust H_2/H_∞ linear parameter varying(LPV) controller for the longitudinal motion of an air-breathing hypersonic vehicle via a high order singular value decomposition(H...This paper focuses on synthesizing a mixed robust H_2/H_∞ linear parameter varying(LPV) controller for the longitudinal motion of an air-breathing hypersonic vehicle via a high order singular value decomposition(HOSVD) approach.The design of hypersonic flight control systems is highly challenging due to the enormous complexity of the vehicle dynamics and the presence of significant uncertainties.Motivated by recent results on both LPV control and tensor-product(TP) model transformation approach,the velocity and altitude tracking control problems for the air-breathing hypersonic vehicle is reduced to that of a state feedback stabilizing controller design for a polytopic LPV system with guaranteed performances.The controller implementation is converted into a convex optimization problem with parameterdependent linear matrix inequalities(LMIs) constraints,which is intuitively tractable using LMI control toolbox.Finally,numerical simulation results demonstrate the effectiveness of the proposed approach.展开更多
Schottky diodes with an Ag/n-Si/W/Cu structure and 100μm in diameter were studied.Analyzing the silver metal surface coating on the n-Si substrate using a scanning probe microscopy(SPM) device showed a large number...Schottky diodes with an Ag/n-Si/W/Cu structure and 100μm in diameter were studied.Analyzing the silver metal surface coating on the n-Si substrate using a scanning probe microscopy(SPM) device showed a large number of nano patches in the surface with dimensions of 0 to 100 nm.The potential distribution of the patches revealed that the potential of each patch with the neighboring patches was different.The electrical characteristics of the devices were studied between temperature ranges of 300 and 380 K.When the temperature ideality factor approximately increases,the potential barrier height decreases.The potential barrier height was calculated separately from theⅠ-Ⅴand C-V characteristics.The main reasons for the significant difference between room temperature and higher temperatures were the differences in patch distribution,the different potentials of each patch,and the interactions between them.The effective potential barrier height depended on the degree of inhomogeneity,and thus the operating potential barrier height in the contact surface was smaller than the average value,and the ideality factor was more than unitary.With the increase in the potential value,the ideality factor becomes close to unitary, and with increasing temperatures,the ideality factor is increased.In this case,the maximum potential barrier height accrues at a greater distance from the metal contact.For this reason,at high temperatures the average value of the potential barrier height is smaller.Moreover,with increasing temperature,the ideality factor is increased.展开更多
A numerical method is developed to evaluate the dynamic stability parameters of aircraft. This method is based on the aerodynamic model proposed by Etkin. His model is analyzed and generalized. After giving the specif...A numerical method is developed to evaluate the dynamic stability parameters of aircraft. This method is based on the aerodynamic model proposed by Etkin. His model is analyzed and generalized. After giving the specific forms of the aerodynamic model, the dynamic stability parameters are determined by the unsteady flow field computation and a parameter identification technique. Numerical experiments show that this method is accurate in predicting the dynamic stability characteristics of blunt cones in hypersonic flight.展开更多
文摘Based on the numerical simulation analysis, structure parameters of the high pressure fuel pump and common rail as well as flow limiter are designed and the GD-1 high pressure common rail fuel injection system is self-developed. Fuel injection characteristics experiment is performed on the GD-1 system. And double-factor variance analysis is applied to investigate the influence of the rail pressure and injection pulse width on the consistency of fuel injection quantity, thus to test whether the design of structure parameters is sound accordingly. The results of experiment and test show that rail pressure and injection pulse width as well as their mutual-effect have no influence on the injection quantity consistency, which proves that the structure parameters design is successful and performance of GD-1 system is sound.
基金Indian National Centre for Ocean Information Services(INCOIS)of the Ministry of Earth Science of Indiathe INSPIRE fellowship of Department of Science and Technology of India
文摘The spatial distribution of physico-chemical parameters(sea surface temperature(SST), p H, sea surface salinity(SSS), dissolved oxygen(DO) and Secchi depth) along with filterable nutrients(dissolved inorganic nitrate(DIN),dissolved inorganic phosphate(DIP) and reactive silicate(DSi)) are measured in the winter months of November,December, January and February for four consecutive years from 2009–2010 to 2012–2013 on the shallow continental shelf(〈20 m bathymetry) of the coastal waters(up to 18 km away from shoreline) of the northern Bay of Bengal(n Bo B) during the highest high tide(HHT) and lowest low tide(LLT) hours for the first time. The variability of the coastal biogeochemical environment is assessed during the HHT and LLT hours and for this purpose, seawater samples are collected from seven different locations of a transect in the coastal region. Physicochemical parameters(except SST) show significant difference in magnitude during the HHT and LLT hours respectively. p H, SSS and DO are found to increase in the HHT hours and vice-versa. The data reveal that during the LLT hours, a relative increase of freshwater input in the n Bo B can have elevated the nutrient concentration compared with that observed during the HHT hours. The ratio of nutrient concentration is found to deviate significantly from the Redfield ratio. The abundance of DIP is much higher compared with that of DIN and DSi.The anthropogenic sources of DIP from the upstream flow(especially the domestic effluent of several metropolises) can be mainly attributed behind such an observation. In order to characterize and establish the trend of such variation in such an important bio-climatic region, long-term and systematic ecosystem monitoring in the coastal water of the n Bo B northern Bay of Bengal should be carried out throughout the year.
基金supported by the National Natural Science Foundation of China(6120300761304239+1 种基金61503392)the Natural Science Foundation of Shaanxi Province(2015JQ6213)
文摘This paper focuses on synthesizing a mixed robust H_2/H_∞ linear parameter varying(LPV) controller for the longitudinal motion of an air-breathing hypersonic vehicle via a high order singular value decomposition(HOSVD) approach.The design of hypersonic flight control systems is highly challenging due to the enormous complexity of the vehicle dynamics and the presence of significant uncertainties.Motivated by recent results on both LPV control and tensor-product(TP) model transformation approach,the velocity and altitude tracking control problems for the air-breathing hypersonic vehicle is reduced to that of a state feedback stabilizing controller design for a polytopic LPV system with guaranteed performances.The controller implementation is converted into a convex optimization problem with parameterdependent linear matrix inequalities(LMIs) constraints,which is intuitively tractable using LMI control toolbox.Finally,numerical simulation results demonstrate the effectiveness of the proposed approach.
文摘Schottky diodes with an Ag/n-Si/W/Cu structure and 100μm in diameter were studied.Analyzing the silver metal surface coating on the n-Si substrate using a scanning probe microscopy(SPM) device showed a large number of nano patches in the surface with dimensions of 0 to 100 nm.The potential distribution of the patches revealed that the potential of each patch with the neighboring patches was different.The electrical characteristics of the devices were studied between temperature ranges of 300 and 380 K.When the temperature ideality factor approximately increases,the potential barrier height decreases.The potential barrier height was calculated separately from theⅠ-Ⅴand C-V characteristics.The main reasons for the significant difference between room temperature and higher temperatures were the differences in patch distribution,the different potentials of each patch,and the interactions between them.The effective potential barrier height depended on the degree of inhomogeneity,and thus the operating potential barrier height in the contact surface was smaller than the average value,and the ideality factor was more than unitary.With the increase in the potential value,the ideality factor becomes close to unitary, and with increasing temperatures,the ideality factor is increased.In this case,the maximum potential barrier height accrues at a greater distance from the metal contact.For this reason,at high temperatures the average value of the potential barrier height is smaller.Moreover,with increasing temperature,the ideality factor is increased.
文摘A numerical method is developed to evaluate the dynamic stability parameters of aircraft. This method is based on the aerodynamic model proposed by Etkin. His model is analyzed and generalized. After giving the specific forms of the aerodynamic model, the dynamic stability parameters are determined by the unsteady flow field computation and a parameter identification technique. Numerical experiments show that this method is accurate in predicting the dynamic stability characteristics of blunt cones in hypersonic flight.