Al-substituted α-Ni（OH）2 was synthesized under different reaction conditions by a homogeneous precipitation method. The effect of reaction temperature, reaction time, Ni and Al ions concentration and reagent ratio ...Al-substituted α-Ni（OH）2 was synthesized under different reaction conditions by a homogeneous precipitation method. The effect of reaction temperature, reaction time, Ni and Al ions concentration and reagent ratio on the physico-chemical properties and electrochemical performance of Al-substituted α-Ni（OH）2 was studied. The Al-substituted α-Ni（OH）2 samples were characterized by X-ray diffractometry（XRD）, infrared spectrometry（FT-IR）, inductively coupled plasma（ICP）, thermogravimetry（TG） and electrochemical test. The results reveal that the physico-chemical properties and electrochemical performance of the sample are influenced strongly by the preparation conditions. Keeping reaction temperature at 100 or 104℃ is appropriate and the largest specific discharge capacity of the sample is 320mA·h/g. With the reaction time increasing, the discharge capacity increases first and then decreases slightly. It is appropriate that the Ni and Al ions concentration and the ratio of urea to Ni and Al ions are 0.42mol/L and 0.75∶1, respectively.展开更多
The electrochemical properties of the as-cast CeMg11Ni and ball-milled CeMg11Ni+x% Ni（x=0, 50, 100 and 200, mass fraction） composites were investigated. The results show that homogeneous amorphous phase of CeMg11Ni+...The electrochemical properties of the as-cast CeMg11Ni and ball-milled CeMg11Ni+x% Ni（x=0, 50, 100 and 200, mass fraction） composites were investigated. The results show that homogeneous amorphous phase of CeMg11Ni+x% Ni composite can be obtained by ball-milling, and discharge capacity of the ball-milled CeMg11Ni+x% Ni composites differs greatly depending on the amount of Ni introduced during milling. The CeMg11Ni+200% Ni composite after 90 h ball-milling was found to exhibit a large discharge capacity of about 1 012 mAh/g at 303 K, and it also shows better charge-discharge cycling stability than those with lower Ni content. This remarkable improvement in electrochemical properties of the ball-milled composites seems to be attributed to the formation of an （amorphous） composite as well as the improvement of the surface state of the ball-milled particles.展开更多
We calculate the energy eigenvalues and the sate functions of one-electron Quantum Dot （QD） by using a combination of Quantum Genetic Algorithm （QGA） and Hartre-Fock-Roothaan （HFR） method. The linear and the thi...We calculate the energy eigenvalues and the sate functions of one-electron Quantum Dot （QD） by using a combination of Quantum Genetic Algorithm （QGA） and Hartre-Fock-Roothaan （HFR） method. The linear and the third-order nonlinear optical absorption coefficients for the 1s-1p, 1p-1d, and 1d-1f transitions are examined as a function of the incident photon energy for three different values of the stoichiometric ratio. The results show that the stoichiometric ratio, impurity, relaxation time, and dot size have great influence on the optical absorption coefficients of QDs.展开更多
文摘Al-substituted α-Ni（OH）2 was synthesized under different reaction conditions by a homogeneous precipitation method. The effect of reaction temperature, reaction time, Ni and Al ions concentration and reagent ratio on the physico-chemical properties and electrochemical performance of Al-substituted α-Ni（OH）2 was studied. The Al-substituted α-Ni（OH）2 samples were characterized by X-ray diffractometry（XRD）, infrared spectrometry（FT-IR）, inductively coupled plasma（ICP）, thermogravimetry（TG） and electrochemical test. The results reveal that the physico-chemical properties and electrochemical performance of the sample are influenced strongly by the preparation conditions. Keeping reaction temperature at 100 or 104℃ is appropriate and the largest specific discharge capacity of the sample is 320mA·h/g. With the reaction time increasing, the discharge capacity increases first and then decreases slightly. It is appropriate that the Ni and Al ions concentration and the ratio of urea to Ni and Al ions are 0.42mol/L and 0.75∶1, respectively.
基金Project (TG2000026406) supported by the National Basic Research Development Program of China Project (50471042)supported by the National Natural Science Foundation of China
文摘The electrochemical properties of the as-cast CeMg11Ni and ball-milled CeMg11Ni+x% Ni（x=0, 50, 100 and 200, mass fraction） composites were investigated. The results show that homogeneous amorphous phase of CeMg11Ni+x% Ni composite can be obtained by ball-milling, and discharge capacity of the ball-milled CeMg11Ni+x% Ni composites differs greatly depending on the amount of Ni introduced during milling. The CeMg11Ni+200% Ni composite after 90 h ball-milling was found to exhibit a large discharge capacity of about 1 012 mAh/g at 303 K, and it also shows better charge-discharge cycling stability than those with lower Ni content. This remarkable improvement in electrochemical properties of the ball-milled composites seems to be attributed to the formation of an （amorphous） composite as well as the improvement of the surface state of the ball-milled particles.
文摘We calculate the energy eigenvalues and the sate functions of one-electron Quantum Dot （QD） by using a combination of Quantum Genetic Algorithm （QGA） and Hartre-Fock-Roothaan （HFR） method. The linear and the third-order nonlinear optical absorption coefficients for the 1s-1p, 1p-1d, and 1d-1f transitions are examined as a function of the incident photon energy for three different values of the stoichiometric ratio. The results show that the stoichiometric ratio, impurity, relaxation time, and dot size have great influence on the optical absorption coefficients of QDs.
