Fast non‐iterative calculation of solvation energies for water and non‐aqueous solvents

2021 ◽  
Author(s):  
Sergei F. Vyboishchikov ◽  
Alexander A. Voityuk
Keyword(s):  
Iterative Calculation ◽  
Solvation Energies

Ion solvation by dipolar aprotic solvents. An ab initio study

1987 ◽  
Vol 52 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Petr Kyselka ◽  
Zdeněk Havlas ◽  
Ivo Sláma
Keyword(s):  
Ab Initio ◽  
Geometry Optimization ◽  
Molecular Structures ◽  
Dimethyl Sulphoxide ◽  
Ion Solvation ◽  
Interaction Energies ◽  
Ab Initio Study ◽  
Solvation Energies ◽  
Dipolar Aprotic Solvents ◽  
Complete Geometry Optimization

The paper deals with the solvation of Li+, Be2+, Na+, Mg2+, and Al3+ ions in dimethyl sulphoxide, dimethylformamide, acetonitrile, and water. The ab initio quantum chemical method was used to calculate the solvation energies, molecular structures, and charge distributions for the complexes water···ion, acetonitrile···ion, dimethyl sulphoxide···ion, and dimethylformamide···ion. The interaction energies were corrected for the superposition error. Complete geometry optimization was performed for the complex water···ion. Some generalizations are made on the basis of the results obtained.

scholarly journals Estimation for Two-Dimensional Nonsymmetric Coherently Distributed Source in L-Shaped Arrays

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Tao Wu ◽  
Zhenghong Deng ◽  
Qingyue Gu ◽  
Jiwei Xu
Keyword(s):  
Expectation Maximization ◽  
Two Dimensional ◽  
Signal Distribution ◽  
Distributed Source ◽  
One Dimensional ◽  
Least Squares Estimators ◽  
Iterative Calculation ◽  
Symmetric Source ◽  
Relationship Of ◽  
The Relationship

We explore the estimation of a two-dimensional (2D) nonsymmetric coherently distributed (CD) source using L-shaped arrays. Compared with a symmetric source, the modeling and estimation of a nonsymmetric source are more practical. A nonsymmetric CD source is established through modeling the deterministic angular signal distribution function as a summation of Gaussian probability density functions. Parameter estimation of the nonsymmetric distributed source is proposed under an expectation maximization (EM) framework. The proposed EM iterative calculation contains three steps in each cycle. Firstly, the nominal azimuth angles and nominal elevation angles of Gaussian components in the nonsymmetric source are obtained from the relationship of rotational invariance matrices. Then, angular spreads can be solved through one-dimensional (1D) searching based on nominal angles. Finally, the powers of Gaussian components are obtained by solving least-squares estimators. Simulations are conducted to verify the effectiveness of the nonsymmetric CD model and estimation technique.

Differential Equation Based Adaptive Distance Relaying Setting Method for Series Compensated Line

2014 ◽  
Vol 1044-1045 ◽  
pp. 482-485
Author(s):  
Jin Hu Zhang ◽  
Zhen Yu Xu ◽  
Zhi Peng Su
Keyword(s):  
Differential Equation ◽  
Transmission Lines ◽  
Distance Relay ◽  
Iterative Calculation ◽  
Simple Simulation ◽  
Simulation Results ◽  
Distance Relays ◽  
Distance Relaying

The distance relays of transmission lines find limitations in the presence of series compensated capacitor. One of them is the distance relay setting issue, in which either over-reach problem or under-reach problem may occur. To deal with this issue, a differential equation based adaptive distance relaying setting method for series compensated line is proposed. As for it do not need to identify whether SC/MOV is in fault loop, not need to know the parameters and the operating states of SC/MOV/GAP, and furthermore, it can be realized without the iterative calculation, it is very suitable to be used for the distance relaying adaptive setting of series compensated line. Simple simulation results certificate the proposed adaptive setting method.

Accelerated Iterative Calculation of Transonic Nacelle Flowfields

AIAA Journal ◽  
1977 ◽  
Vol 15 (10) ◽  
pp. 1474-1480 ◽  
Author(s):  
D.A. Caughey ◽  
Antony Jameson
Keyword(s):  
Iterative Calculation

scholarly journals Obstacle Avoidance Control for Multisteering Mode of Multiaxle Wheeled Robot Based on Trajectory Prediction Strategy

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yongqiang Zhu ◽  
Junru Zhu ◽  
Pingxia Zhang
Keyword(s):  
Obstacle Avoidance ◽  
Control Strategy ◽  
Trajectory Prediction ◽  
Coverage Area ◽  
Iterative Calculation ◽  
Wheeled Robot ◽  
Avoidance Control ◽  
Narrow Space ◽  
The Relationship ◽  
Prediction Strategy

A multiaxle wheeled robot is difficult to be controlled due to its long body and a large number of axles, especially for obstacle avoidance and steering in narrow space. To solve this problem, a multisteering mode control strategy based on front and rear virtual wheels is proposed, and the driving trajectory prediction of the multiaxle wheeled robot is analyzed. On this basis, an obstacle avoidance control strategy based on trajectory prediction is proposed. By calculating the relationship between the lidar points of the obstacle and the trajectory coverage area, the iterative calculation of the obstacle avoidance scheme for the proposed steering is carried out, and the feasible obstacle avoidance scheme is obtained. The mechanical structure, hardware, and software control system of a five-axle wheeled robot are designed. Finally, to verify the effectiveness of the obstacle avoidance strategy, a Z-shaped obstacle avoidance experiment was carried out. The results confirm the effectiveness of the proposed control strategy.

scholarly journals Improving Solvation Energy Predictions Using The SMD Solvation Method and Semiempirical Electronic Structure Methods

2018 ◽  
Author(s):  
Jimmy C. Kromann ◽  
Casper Steinmann ◽  
Jan Halborg Jensen
Keyword(s):  
Continuum Model ◽  
Solvation Energy ◽  
Solvation Model ◽  
Polar Solvents ◽  
Data Set ◽  
Solvation Energies ◽  
Polarized Continuum Model ◽  
Electronic Structure Methods ◽  
Aqueous Solvation ◽  
Model C

The PM6 implementation in the GAMESS program is extended to elements requiring d-integrals and interfaced with the conducter-like polarized continuum model (C-PCM) of solvation, in- cluding gradients. The accuracy of aqueous solvation energies computed using AM1, PM3, PM6, and DFTB and the SMD continuum solvation model is tested using the MNSOL data set. The errors in SMD solvation energies predicted using NDDO-based methods is considerably larger than when using DFT and HF, with RMSE values of 3.4-5.9 (neutrals) and 6-15 kcal/mol (ions) compared to 2.4 and ca 5 kcal/mol for HF/6-31G(d). For the NDDO-based methods the errors are especially large for cations and considerably higher than the corresponding COSMO results, which suggests that the NDDO/SMD results can be improved by re-parameterizing the SMD parameters focusing on ions. We found the best results are obtained by changing only the radii for hydrogen, carbon, oxygen, nitrogen, and sulfur and this leads to RMSE values for PM3 (neutrals: 2.8/ions: ca 5 kcal/mol), PM6 (4.7/ca 5 kcal/mol), and DFTB (3.9/ca 5 kcal/mol) that are more comparable to HF/6-31G(d) (2.4/ca 5 kcal/mol). Though the radii are optimized to reproduce aqueous solvation energies, they also lead more accurate predictions for other polar solvents such as DMSO, acetonitrile, and methanol, while the improvements for non-polar solvents are negligible.

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