The depletion rate of phosphate in the soil-root interface zone increased along with growth and phosphateuptake of wheat or maize, which indicated that the phosphate distribution in soil near the root surfaceagreed we...The depletion rate of phosphate in the soil-root interface zone increased along with growth and phosphateuptake of wheat or maize, which indicated that the phosphate distribution in soil near the root surfaceagreed well with the phosphate movement in rhizosphere and phosphate uptake by plant. The relativeaccumulation zone of phosphate within 0.5 mm apart from the root surface developed at the 15th day or soafter cultivating wheat or maize since the root phosphate secretion increased gradually in this stage. Thephosphate distribution in the soil-root interface zone against the growing time (t) and the distance from theroot plane (x) could be described by the non-linear regression equation with the third powers of x and t.展开更多
A new mobile multicast scheme called mobility prediction based mobile multicast(MPBMM) was proposed. In MPBMM, when a mobile node (MN) roams among subnets during a multicast session, MN predicts the next subnet, to wh...A new mobile multicast scheme called mobility prediction based mobile multicast(MPBMM) was proposed. In MPBMM, when a mobile node (MN) roams among subnets during a multicast session, MN predicts the next subnet, to which MN will attach, by the information of its position and mobility speed, consequently speeds up the handoff procedure. Simulation results show that the proposed scheme can minimize the loss of multicast packets, reduce the delay of subnet handoff, decrease the frequency of multicast tree reconfiguration, and optimize the delivery path of multicast packets. When MN moves among subnets at different speeds (from 5 to 25 ms), the maximum loss ratio of multicast packets is less than0.2%, the maximum inter-arrival time of multicast packets is 117 ms, so the proposed scheme can meet the QoS requirements of real-time services. In addition, MPBMM can support the mobility of multicast source.展开更多
The boron adsorption kinetic experiment in soil by means of a flow displacement technique showed that the kinetic data could be described with some mathematic equations. The average values of the correlation coefficie...The boron adsorption kinetic experiment in soil by means of a flow displacement technique showed that the kinetic data could be described with some mathematic equations. The average values of the correlation coefficient for zero-order, first-order, parabolic diffusion, Elovich, power function and exponential equations were 0.957, 0.982, 0.981, 0.984, 0.981 and 0.902, respectively. The correlation between adsorbed boron or its other expression form and time were the highest for first-order, parabolic diffusion, Elovich, and power function equations, the second for the zeroorder equation, and the lowest for the exponential equation. The parabolic diffusion equation fitted well the experimental results, with the least standard error among the six kinetic equations, showing that the movement of boron from soil solution to soil colloid surface may be controlled by boron diffusion speed. The boron content of rape seedling obtained from soil cultivation was correlated with the rate constants of the kinetic equations. The constants of first-order, parabolic diffusion,and exponential equations were significantly correlated with the boron content of the crop of NPK treatment at a 95% probability level, with correlation coefficients being 0.686, 0.691 and 0.641, respectively. In the case of zero-order equation, it was significant at 99% probability level (r =0.736). These results showed that the absorption kinetic constants of soil boron were closely related with the rape plant response to boron.展开更多
In an atrocious ocean environment,the lateral propulsion hole could potentially be partly out of water and capture an air cavity.Bubbles would form when the captured air cavity escapes underwater and they may affect t...In an atrocious ocean environment,the lateral propulsion hole could potentially be partly out of water and capture an air cavity.Bubbles would form when the captured air cavity escapes underwater and they may affect the performance of the sonar.The common commercial computational fluid dynamics software CFX was adopted to calculate the ambient flow field around the lateral propulsion hole generated by a moving vessel.The oscillation of the spherical bubble was based on the Rayleigh-Plesset equation and its migration was modeled using the momentum equation.The radiated noise of the oscillating bubble was also studied.The aim is that the results from this paper would provide some insight into corresponding fluid and acoustic study.展开更多
The increasing overlap of core and colony populations during the anaphase of evolution may limit the performance of shifting balance genetic algorithms. To decrease such overlapping,so as to increase the local search ...The increasing overlap of core and colony populations during the anaphase of evolution may limit the performance of shifting balance genetic algorithms. To decrease such overlapping,so as to increase the local search capability of the core population,the sub-space method was used to generate uniformly distributed initial colony populations over the decision variable space. The core population was also dynamically divided,making simultaneous searching in several local spaces possible. The algorithm proposed in this paper was compared to the original one by searching for the optimum of a complicated multi-modal function. The results indicate that the solutions obtained by the modified algorithm are better than those of the original algorithm.展开更多
The potential energy surface for the migration of an extra Ga atom on the GaAs（001） β2（2×4） surfuce was mapped out by performing calculations at the level of analytical bond-order potential. Based on this ca...The potential energy surface for the migration of an extra Ga atom on the GaAs（001） β2（2×4） surfuce was mapped out by performing calculations at the level of analytical bond-order potential. Based on this calculations, we found some lower-energy sites for the adsorption of an extra Ga atom in the surface, which were in agreement with the experimental data. Moreover, many possible pathways for an extra Ga atom diffusing in this surface were revealed. According to the relative energies of the possible pathways, the individual Ga adatoms preferably keep their diffusion in two pathways parallel to the As dimers. This result can be understood using the strain caused by the diffusing Ga atom in the pathways. In addition, the simulated kinetic processes of the extra Ga atom diffusing in different pathways at finite temperatures support the prediction from our calculated potential energy surface.展开更多
Metolachlor retention on a Sharkey clay soil was quantified using a kinetic batch method for different initial solution concentrations. Time-dependent adsorption was carried out by monitoring solution concentration at...Metolachlor retention on a Sharkey clay soil was quantified using a kinetic batch method for different initial solution concentrations. Time-dependent adsorption was carried out by monitoring solution concentration at different reaction times. Adsorption was found to be highly kinetic in nature. Attempts were made to describe metolachlor retention based on a kinetic multireaction model which includes reversible and irreversible retention processes of the equilibrium and kinetic types. The predictive capability of the model for the description of experimental results for metolachlor retention was examined and proved to be adequate.展开更多
Motivated by a grain boundary(GB) healing mechanism that GB turns into a mobile sink through migration to eliminate the vacancies in a bulk, we have further investigated the influence of the retained hydrogen(H) on th...Motivated by a grain boundary(GB) healing mechanism that GB turns into a mobile sink through migration to eliminate the vacancies in a bulk, we have further investigated the influence of the retained hydrogen(H) on the GB migration in tungsten using a molecular dynamics simulation. We show that H hinders the GB migration at different H concentrations and temperatures, and such friction of GB migration due to the presence of H increases with the H concentration and decreases with temperature. We demonstrate that H follows the GB-migration as the temperature is higher than 300 K. Most importantly, the presence of H induces a disordering of GB, which affects the GB migration significantly.展开更多
文摘The depletion rate of phosphate in the soil-root interface zone increased along with growth and phosphateuptake of wheat or maize, which indicated that the phosphate distribution in soil near the root surfaceagreed well with the phosphate movement in rhizosphere and phosphate uptake by plant. The relativeaccumulation zone of phosphate within 0.5 mm apart from the root surface developed at the 15th day or soafter cultivating wheat or maize since the root phosphate secretion increased gradually in this stage. Thephosphate distribution in the soil-root interface zone against the growing time (t) and the distance from theroot plane (x) could be described by the non-linear regression equation with the third powers of x and t.
基金Project (60573127) supported by the National Natural Science Foundation of ChinaProject (20040533036) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China+1 种基金Project (05JJ40131) supported by the Natural Science Foundation of Hunan Province, ChinaProject(03C326) supported by the Natural Science Foundation of Education Department of Hunan Province, China
文摘A new mobile multicast scheme called mobility prediction based mobile multicast(MPBMM) was proposed. In MPBMM, when a mobile node (MN) roams among subnets during a multicast session, MN predicts the next subnet, to which MN will attach, by the information of its position and mobility speed, consequently speeds up the handoff procedure. Simulation results show that the proposed scheme can minimize the loss of multicast packets, reduce the delay of subnet handoff, decrease the frequency of multicast tree reconfiguration, and optimize the delivery path of multicast packets. When MN moves among subnets at different speeds (from 5 to 25 ms), the maximum loss ratio of multicast packets is less than0.2%, the maximum inter-arrival time of multicast packets is 117 ms, so the proposed scheme can meet the QoS requirements of real-time services. In addition, MPBMM can support the mobility of multicast source.
文摘The boron adsorption kinetic experiment in soil by means of a flow displacement technique showed that the kinetic data could be described with some mathematic equations. The average values of the correlation coefficient for zero-order, first-order, parabolic diffusion, Elovich, power function and exponential equations were 0.957, 0.982, 0.981, 0.984, 0.981 and 0.902, respectively. The correlation between adsorbed boron or its other expression form and time were the highest for first-order, parabolic diffusion, Elovich, and power function equations, the second for the zeroorder equation, and the lowest for the exponential equation. The parabolic diffusion equation fitted well the experimental results, with the least standard error among the six kinetic equations, showing that the movement of boron from soil solution to soil colloid surface may be controlled by boron diffusion speed. The boron content of rape seedling obtained from soil cultivation was correlated with the rate constants of the kinetic equations. The constants of first-order, parabolic diffusion,and exponential equations were significantly correlated with the boron content of the crop of NPK treatment at a 95% probability level, with correlation coefficients being 0.686, 0.691 and 0.641, respectively. In the case of zero-order equation, it was significant at 99% probability level (r =0.736). These results showed that the absorption kinetic constants of soil boron were closely related with the rape plant response to boron.
基金Supported by the National Science Foundation of China （11002038）Key Project of National Natural Science Funds （50939002）+2 种基金National Defense Foundation Scientific Project （B2420110011）the National Science Foundation for Young Scientists of China （51009035）Natural Science Funds of Heilongjiang Province （E201047,A200901）
文摘In an atrocious ocean environment,the lateral propulsion hole could potentially be partly out of water and capture an air cavity.Bubbles would form when the captured air cavity escapes underwater and they may affect the performance of the sonar.The common commercial computational fluid dynamics software CFX was adopted to calculate the ambient flow field around the lateral propulsion hole generated by a moving vessel.The oscillation of the spherical bubble was based on the Rayleigh-Plesset equation and its migration was modeled using the momentum equation.The radiated noise of the oscillating bubble was also studied.The aim is that the results from this paper would provide some insight into corresponding fluid and acoustic study.
基金Project 60575046 supported by the National Natural Science Foundation of China
文摘The increasing overlap of core and colony populations during the anaphase of evolution may limit the performance of shifting balance genetic algorithms. To decrease such overlapping,so as to increase the local search capability of the core population,the sub-space method was used to generate uniformly distributed initial colony populations over the decision variable space. The core population was also dynamically divided,making simultaneous searching in several local spaces possible. The algorithm proposed in this paper was compared to the original one by searching for the optimum of a complicated multi-modal function. The results indicate that the solutions obtained by the modified algorithm are better than those of the original algorithm.
基金ACKNOWLEDGMENTS This work was supported by the Fund of University of Science and Technology of China, the Fund of Chinese Academy of Science, and the National Natural Science Foundation of China （No.50121202 and No.60176024）.
文摘The potential energy surface for the migration of an extra Ga atom on the GaAs（001） β2（2×4） surfuce was mapped out by performing calculations at the level of analytical bond-order potential. Based on this calculations, we found some lower-energy sites for the adsorption of an extra Ga atom in the surface, which were in agreement with the experimental data. Moreover, many possible pathways for an extra Ga atom diffusing in this surface were revealed. According to the relative energies of the possible pathways, the individual Ga adatoms preferably keep their diffusion in two pathways parallel to the As dimers. This result can be understood using the strain caused by the diffusing Ga atom in the pathways. In addition, the simulated kinetic processes of the extra Ga atom diffusing in different pathways at finite temperatures support the prediction from our calculated potential energy surface.
文摘Metolachlor retention on a Sharkey clay soil was quantified using a kinetic batch method for different initial solution concentrations. Time-dependent adsorption was carried out by monitoring solution concentration at different reaction times. Adsorption was found to be highly kinetic in nature. Attempts were made to describe metolachlor retention based on a kinetic multireaction model which includes reversible and irreversible retention processes of the equilibrium and kinetic types. The predictive capability of the model for the description of experimental results for metolachlor retention was examined and proved to be adequate.
基金supported by the National Magnetic Confinement Fusion Program(Grant No.2013GB109002)the National Natural Science Foundation of China(Grant Nos.51171008 and 51325103)
文摘Motivated by a grain boundary(GB) healing mechanism that GB turns into a mobile sink through migration to eliminate the vacancies in a bulk, we have further investigated the influence of the retained hydrogen(H) on the GB migration in tungsten using a molecular dynamics simulation. We show that H hinders the GB migration at different H concentrations and temperatures, and such friction of GB migration due to the presence of H increases with the H concentration and decreases with temperature. We demonstrate that H follows the GB-migration as the temperature is higher than 300 K. Most importantly, the presence of H induces a disordering of GB, which affects the GB migration significantly.
