A new construction of constant-composition codes based on all known perfect nonlinear functions from Fqm to itself is presented, which provides a kind of unified constructions of constant-composition codes based on al...A new construction of constant-composition codes based on all known perfect nonlinear functions from Fqm to itself is presented, which provides a kind of unified constructions of constant-composition codes based on all known perfect nonlinear functions from F qm to itself.It is proved that the new constant-composition codes are optimal with respect to the Luo-Fu-Vinck-Chen bound, when m is an odd positive integer greater than 1.Finally, we point out that two constructions of constant-composition codes, proposed by Ding Cunsheng et al.in 2005, are equivalent to two special types of the new constant-composition codes.展开更多
A constant-composition technique has been used to study thekinetic of dissolution of barium fluoride in which the activities of the latticeions were maintained constant during the experiments. The method enableskineti...A constant-composition technique has been used to study thekinetic of dissolution of barium fluoride in which the activities of the latticeions were maintained constant during the experiments. The method enableskinetic data to be obtained at very low undersaturation. A striking change inthe mechanism of dissolution is observed as the driving force is changed. Athigher driving forces (relative undersaturation 0.15--0.20) the process appearsto follow normal diffusion-controlled dissolution, while at very low undersatu-ration (0.04--0.12) a surface controlled reaction predominates. The tworegions of undersaturation a show marked difference in reactions.展开更多
基金Supported in part by the National Natural Science Foundation of China (Grant Nos 60573028, 60803156)the Open Research Fund of the National Mobile Communications Research Laboratory of Southeast University (Grant No W200805)in part by Singapore Ministry of Education Academic Research Fund (Grant No T206B2204)
文摘A new construction of constant-composition codes based on all known perfect nonlinear functions from Fqm to itself is presented, which provides a kind of unified constructions of constant-composition codes based on all known perfect nonlinear functions from F qm to itself.It is proved that the new constant-composition codes are optimal with respect to the Luo-Fu-Vinck-Chen bound, when m is an odd positive integer greater than 1.Finally, we point out that two constructions of constant-composition codes, proposed by Ding Cunsheng et al.in 2005, are equivalent to two special types of the new constant-composition codes.
文摘A constant-composition technique has been used to study thekinetic of dissolution of barium fluoride in which the activities of the latticeions were maintained constant during the experiments. The method enableskinetic data to be obtained at very low undersaturation. A striking change inthe mechanism of dissolution is observed as the driving force is changed. Athigher driving forces (relative undersaturation 0.15--0.20) the process appearsto follow normal diffusion-controlled dissolution, while at very low undersatu-ration (0.04--0.12) a surface controlled reaction predominates. The tworegions of undersaturation a show marked difference in reactions.
