In this paper we investigate the impact of the Atmospheric Infra-Red Sounder (AIRS) temperature retrievals on data assimilation and the resulting forecasts using the four-dimensional Local Ensemble Transform Kalman Fi...In this paper we investigate the impact of the Atmospheric Infra-Red Sounder (AIRS) temperature retrievals on data assimilation and the resulting forecasts using the four-dimensional Local Ensemble Transform Kalman Filter (LETKF) data assimilation scheme and a reduced resolution version of the NCEP Global Forecast System (GFS).Our results indicate that the AIRS temperature retrievals have a significant and consistent positive impact in the Southern Hemispheric extratropics on both analyses and forecasts,which is found not only in the temperature field but also in other variables.In tropics and the Northern Hemispheric extratropics these impacts are smaller,but are still generally positive or neutral.展开更多
The influence of nano-particles on CO2 absorption was studied experimentally in a stirred thermostatic reactor. Nano-A1203 and carbon nanotube （CNT） particles which showed different hydrophobic properties were chose...The influence of nano-particles on CO2 absorption was studied experimentally in a stirred thermostatic reactor. Nano-A1203 and carbon nanotube （CNT） particles which showed different hydrophobic properties were chosen for the investigation. The experimental results were compared with that of micron-size activated carbon （AC） and Al2O3 particles. From the results, no enhancement by micron-size A1203 was found, and with the increase of A1203 concentration, the enhancement factor decreased. However, nano-Al203 showed a weak enlaancement tor me COz absorption. AC and CNT particles all intensified the gas-liquid mass transfer effectively, yet the trend of the enhancement factor with stirring speed for the two particles was different. With increasing stirring speed, the enhancement factor of AC particles was decreased, wl＇iereas in CNT suspensions it was increased. The experimental phenomena demonstrated a difference in enhancement mechanism for different size particles. For nano-particles, besides the influence of adsorbability and hydrophobicity, the micro-convection caused by Brownian motion should be also taken into account. Considering the micro-convection effect, a theoretical model was developed to shed light on the absorption enhancement bv nano-oarticles.展开更多
Accurate expression for photoabsorption (photoionization) cross sections of high density system proposed recently is used to study the photoionization of solid gold. The results show that the present theoretical photo...Accurate expression for photoabsorption (photoionization) cross sections of high density system proposed recently is used to study the photoionization of solid gold. The results show that the present theoretical photoianization cross sections have good agreement both in structure and in magnitude with the experimental results of gold crystal. The studies also indicate that both the real part epsilon' and the imaginary part epsilon' of the complex dielectric constant epsilon and the dielectric influence function of a nonideal system have rich structures in low energy side with a range about 50 eV, and suggest that the influence of particle interactions of surrounding particles with the photoionized particle on the photoionization cross sections can be easily investigated using the dielectric influence function. The electron overlap effects are suggested to be implemented in the future studies to improve the accuracy of theoretical photoionization cross sections of a solid system.展开更多
Nitrogen （N） is the element with the greatest influence on the growth of vegetables and ornamentals, however, form of delivery, either as nitrate （NO3） or ammonium （NH4＋） has different effects on plant developm...Nitrogen （N） is the element with the greatest influence on the growth of vegetables and ornamentals, however, form of delivery, either as nitrate （NO3） or ammonium （NH4＋） has different effects on plant development. The NO3 is the main form of N that plants absorb, but when it is the only source of N that has slight effects on root growth, no effects over enzymatic activities, and stimulates the absorption and translocation of cations within the plant. The NH4＋ is the easiest way of assimilation but is highly toxic when the only source or with respect to the concentration of NO3 is too high. To avoid toxicity, the NH4＋ must not exceed 20% of the total N amount in the formulation, however, it is important to consider the species, variety and environmental conditions. The N as supplied also affects the resistance or susceptibility of plants to diseases, but depends on the species and the type of pathogen.展开更多
基金National Natural Science Foundation of China (40975067)973 Program (2009CB421500)+1 种基金CMA Grant GYHY200806029NASA grant NNX07AM97G in U.S.A
文摘In this paper we investigate the impact of the Atmospheric Infra-Red Sounder (AIRS) temperature retrievals on data assimilation and the resulting forecasts using the four-dimensional Local Ensemble Transform Kalman Filter (LETKF) data assimilation scheme and a reduced resolution version of the NCEP Global Forecast System (GFS).Our results indicate that the AIRS temperature retrievals have a significant and consistent positive impact in the Southern Hemispheric extratropics on both analyses and forecasts,which is found not only in the temperature field but also in other variables.In tropics and the Northern Hemispheric extratropics these impacts are smaller,but are still generally positive or neutral.
文摘The influence of nano-particles on CO2 absorption was studied experimentally in a stirred thermostatic reactor. Nano-A1203 and carbon nanotube （CNT） particles which showed different hydrophobic properties were chosen for the investigation. The experimental results were compared with that of micron-size activated carbon （AC） and Al2O3 particles. From the results, no enhancement by micron-size A1203 was found, and with the increase of A1203 concentration, the enhancement factor decreased. However, nano-Al203 showed a weak enlaancement tor me COz absorption. AC and CNT particles all intensified the gas-liquid mass transfer effectively, yet the trend of the enhancement factor with stirring speed for the two particles was different. With increasing stirring speed, the enhancement factor of AC particles was decreased, wl＇iereas in CNT suspensions it was increased. The experimental phenomena demonstrated a difference in enhancement mechanism for different size particles. For nano-particles, besides the influence of adsorbability and hydrophobicity, the micro-convection caused by Brownian motion should be also taken into account. Considering the micro-convection effect, a theoretical model was developed to shed light on the absorption enhancement bv nano-oarticles.
文摘Accurate expression for photoabsorption (photoionization) cross sections of high density system proposed recently is used to study the photoionization of solid gold. The results show that the present theoretical photoianization cross sections have good agreement both in structure and in magnitude with the experimental results of gold crystal. The studies also indicate that both the real part epsilon' and the imaginary part epsilon' of the complex dielectric constant epsilon and the dielectric influence function of a nonideal system have rich structures in low energy side with a range about 50 eV, and suggest that the influence of particle interactions of surrounding particles with the photoionized particle on the photoionization cross sections can be easily investigated using the dielectric influence function. The electron overlap effects are suggested to be implemented in the future studies to improve the accuracy of theoretical photoionization cross sections of a solid system.
文摘Nitrogen （N） is the element with the greatest influence on the growth of vegetables and ornamentals, however, form of delivery, either as nitrate （NO3） or ammonium （NH4＋） has different effects on plant development. The NO3 is the main form of N that plants absorb, but when it is the only source of N that has slight effects on root growth, no effects over enzymatic activities, and stimulates the absorption and translocation of cations within the plant. The NH4＋ is the easiest way of assimilation but is highly toxic when the only source or with respect to the concentration of NO3 is too high. To avoid toxicity, the NH4＋ must not exceed 20% of the total N amount in the formulation, however, it is important to consider the species, variety and environmental conditions. The N as supplied also affects the resistance or susceptibility of plants to diseases, but depends on the species and the type of pathogen.
