21 resultados para accurate
Resumo:
A new kind of shock capturing method is developed. Before applying the high order accurate traditional scheme which is called as base scheme in this paper the fluid parameters are preconditioned in order to control the group velocity. The newly constructed scheme is high order accurate, simple, has high resolution of the shock, and less computer time consumed.
Resumo:
Accurate three-dimensional time-dependent quantum wave packet calculations for the N+OH reaction on the (3)A' potential energy surface [Guadagnini, Schatz, and Walch, J. Chem. Phys. 102, 774 (1995)] have been carried out. The calculations show for the first time that the initial state-selected reaction probabilities are dominated by resonance structures, and the lifetime of the resonance is generally in the subpicosecond time scale. The calculated reaction cross sections indicate that they are a decreasing function of the translational energy, which is in agreement qualitatively with the quasiclassical trajectory calculations. The rate constants obtained from the quantum mechanical calculations are consistent with the quasiclassical trajectory results and the experimental measurements. (C) 2003 American Institute of Physics.
Resumo:
A new algorithm has been developed for simultaneous retrieval of aerosol optical properties and chlorophyll concentrations in case I waters. This algorithm is based on an improved complete model for the inherent optical properties and accurate simulations of the radiative transfer process in the coupled atmosphere-ocean system. It has been tested against synthetic radiances generated for the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) channels and has been shown to be robust and accurate. A unique feature of this algorithm is that it uses the measured radiances in both near-IR and visible channels to find that combination of chlorophyll concentration and aerosol optical properties that minimizes the error across the spectrum. Thus the error in the retrieved quantities can be quantified.
Resumo:
Dissolved inorganic carbon (DIC) account for more than 95% of total carbon in seawater, so it is necessary to make reliable and precise measurements of DIC to study marine carbon cycling. In order to establish a simple and speed method, an airproof device of gas extraction-absorption was designed. Finally a simple method was developed for the determination of DIC in seawater through a large mount of experiments. The determination procedure is as follows: 100 similar to 150 mL seawater was put into conical flask, then add 10% H3PO4, the DIC in seawater sample was dissolved to form CO2 gas and carried by pure N-2, then the CO2 gas was absorbed by two grades 0.1 mol/L NaOH solution. Finally the absorbed solution was titrated by HCl standard solution of 0.01000 mol/L with the end points detected with the indicator phenolphthalein and bromocresol green-methyl red mixture. The precision and accuracy of the method were satisfied. This method was used to analyse seawater samples from Jiaozhou bay in June, 2003. The result shows that the average DIC in surface seawater is 2066 mumol/L, DIC in bottom seawater is 2075 mumol/L inside bay, but the average DIC in surface seawater is 1949 mumol/L, DIC in bottom seawater is 2147 mumol/L outside bay.