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俞汝勤, Ruo Yuan, Ya-Qin Chai, Dong Liu, De Gao, Jun-Zhong Li, and Ru-Qin Yu'
Anal. Chem. 1993, 65, 2572-2575,-0001,():
-1年11月30日
A new solvent polymeric membrane electrode based on Schiff base complexes of Co(II) is described which demonstrates excellent selectivity toward the iodide ion. The resulting electrode exhibits fairly low detection limits and good selectivity properties. The selectivity sequence observed is iodide>thiocyanate~nitrite>perchlorate~bromide>nitrate>chloride>sulfate. The excellent selectivity for iodide is related to the unique interaction between the central Co(II) ion and iodide. The response mechanism of the electrode was also studied with the ac impedance and spectroscopic techniques.
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俞汝勤, Qi Shen, Jian-Hui Jiang, Chen-Xu Jiao, Shuang-Yan Huan, Guo-li Shen, and Ru-Qin Yu*
,-0001,():
-1年11月30日
In quantitative structure-activity relationship (QSAR) modeling, when compounds in a training set exhibit a significant structural distinction between each other, in particular when chemicals of biological interest interacting on the receptor involve a different mechanism, it might be difficult to construct a single linear model for the whole population of compounds of interest with desired residuals. Developing a piecewise linear local model can be effective to circumvent the aforementioned problem. In this paper, piecewise modeling by the particle swarm optimization (PMPSO) approach is applied to QSAR study. The minimum spanning tree is used for clustering all compounds in the training set to form a tree, and the modified discrete PSO is applied to divide the tree to find satisfactory piecewise linear models. A new objective function is formulated for searching the appropriate piecewise linear models. The proposed PMPSO algorithm was used to predict the antagonism of angiotensin II. The results demonstrated that PMPSO is useful for improvement of the performance of regression models.
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俞汝勤, QINGZHANG LU, , GUOLI SHEN, RUQIN YU
,-0001,():
-1年11月30日
The chaotic dynamical system is introduced in g enetic algorithm to train ANN to formulate the CGANN algorithm. Logistic mapping as one of the most important chaotic dynamic mappings provides each new generation a high chance to hold GA's population diversity. This enhances the ability to overcome overfitting in training an ANN. The proposed CGANN has been used for QSAR studies to predict the tetrahedral modes (1(A1) and 2(E)) of halides [MX4]. The frequencies predicted by QSAR were compared with those calculated by quantum chemistry methods including PM3, AM1, and MNDO/d. The possibility of improving the predictive ability of QSAR by including quantum chemistry parameters as feature variables has been investigated using tetrahedral tetrahalide examples.\
chaotic dynamics, genetic algorithm, ANN, tetrahalide species, vibrational frequency\,
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【期刊论文】Surface-Modified Cobalt-Based Sensor as a Phosphate=Sensitive Electrode
俞汝勤, Dan Xiao, Hong-Yan Yuan, Jun Li, and Ru-Qin Yu*
,-0001,():
-1年11月30日
Anew phosphate ion-sensitive electrode based on a cobalt matrix has been prepared. The electrode showed a relalively selective potentiometric response toward H2PO4-which seems to originate from the COO layer covering the electrode surface. The response mechanism of the electrode is discussed in terms of the host-guest chemistry of a nonstoichiometric compound of COO.
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俞汝勤, Qing-zhang Lu¨, †, ‡ Jian-hui Jiang, † Ru-qin Yu, *, † and Guo-li Shen†
J. Chem. Inf. Comput. Sci. 2003, 43, 1132-1137,-0001,():
-1年11月30日
The concept of "prepotency" is introduced in evolution algorithm. The logistic mapping as a simple and powerful device in the chaos theory is combined with the newly proposed prepotency evolution (PE) algorithm to formulate a new genetic algorithm. PE with a population initialized by chaotic numbers is applied to the multiple-layer feed-forward ANN training (PECNN). The logistic mapping ensures the PE starts each time from different initial population never used before. The newly designed PE operator partially includes the crossover and mutation operations implicitly. The proposed algorithm has a higher convergence speed comparing to the conventional GA. During the PE operation the distances between members would become smaller and smaller until all members turning to be almost identical with the potential best minimum being found. It does not waste searching time surrounding the testing minima like the conventional GA and not show symptoms of overfitting to the training set samples. The combination of logistic mapping and PE used in ANN training makes PECNN be able to test lots of minima rapidly and effectively. This greatly enlarges the opportunity to find the global minimum. The proposed algorithm has been testified by prediction of the frequency data of tetrahedral vibration modes (
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