The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predi...The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predict and control the machining distortion, the residual stress distribution in the thick plate must be measured firstly. The modified removal method for measuring residual stress in thick pre-stretched aluminum plates is proposed and the stress-strain relation matrix is deduced by elasticity theory. The residual stress distribution in specimen of 7050T7451 plate is measured by using the method, and measurement results are analyzed and compared with data obtained by other methods. The method is effective to measure the residual stress.展开更多
In the field of adiabatic correction for complex reactions,a simple one-stage kinetic model was used to estimate the real reaction kinetics.However,this assumption simplified the real process,inevitably generated inac...In the field of adiabatic correction for complex reactions,a simple one-stage kinetic model was used to estimate the real reaction kinetics.However,this assumption simplified the real process,inevitably generated inaccurate or even unsafe results.Therefore,it was necessary to find a new correction method for complex reactions.In this work,esterification of acetic anhydride by methanol was chosen as an object reaction of study.The reaction was studied under different conditions by Reaction Calorimeter(RC1).Then,Thermal Safety Software(TSS)was used to establish the kinetic model and estimate the parameters,where,activation energies for three stages were67.09,81.02,73.77 kJ?mol^(-1)respectively,and corresponding frequency factors in logarithmic form were 16.05,19.59,15.72 s^(-1).In addition,two adiabatic tests were performed by Vent Sizing Package2(VSP2).For accurate correction of VSP2 tests,a new correction method based on Enhanced Fisher method was proposed.Combined with kinetics,adiabatic correction of esterification reaction was achieved.Through this research,accurate kinetic parameters for a three-step kinetic model of the esterification reaction were acquired.Furthermore,the correlation coefficients between simulated curves and corrected curves were 0.976 and 0.968,which proved the accuracy of proposed new adiabatic correction method.Based on this new method,conservative corrected results were able to be acquired and be applied in safety assessment.展开更多
The potential energy curves (PECs) of three low-lying electronic states (X^3∑, a^1△, and a^3△) of SO radical have been studied by ab initio quantum chemical method. The calcula- tions were carried out with the ...The potential energy curves (PECs) of three low-lying electronic states (X^3∑, a^1△, and a^3△) of SO radical have been studied by ab initio quantum chemical method. The calcula- tions were carried out with the full valence complete active space self-consistent field method followed by the highly accurate valence internally contracted multireference configuration in- teraction (MRCI) approach in combination with correlation-consistent basis sets. Effects of the core-valence correlation and relativistic corrections on the PECs are taken into account. The core-valence correlation correction is carried out with the cc-pCVDZ basis set. The way to consider the relativistic correction is to use the second-order Douglas-Kroll Hamiltonian approximation, and the correction is performed at the level of cc-pV5Z basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are also corrected for size-extensivity errors by means of the Davidson modification (MRCI+Q). These PECs are extrapolated to the complete basis set limit by the two-point energy extrapolation scheme. With these PECs, the spectroscopic parameters are determined.展开更多
By adopting a result from generalized uncertainty principles (GUP), we modify the inner bound of the membrane model to a physical fixed value and get the cut-offs naturally rather than by hand, which are both in brick...By adopting a result from generalized uncertainty principles (GUP), we modify the inner bound of the membrane model to a physical fixed value and get the cut-offs naturally rather than by hand, which are both in brickwall model and membrane model, and the semi-classical quantization condition could always be valid as well. We also calculate the entropies of Schwarzschild-de Sitter black hole and find the GUP we choose qualitatively shows that the requirement of mass in this method is the same as the natural requirement of the Schwarzschild-de Sitter black hole,which means the method might be self-consistent.展开更多
文摘The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predict and control the machining distortion, the residual stress distribution in the thick plate must be measured firstly. The modified removal method for measuring residual stress in thick pre-stretched aluminum plates is proposed and the stress-strain relation matrix is deduced by elasticity theory. The residual stress distribution in specimen of 7050T7451 plate is measured by using the method, and measurement results are analyzed and compared with data obtained by other methods. The method is effective to measure the residual stress.
文摘In the field of adiabatic correction for complex reactions,a simple one-stage kinetic model was used to estimate the real reaction kinetics.However,this assumption simplified the real process,inevitably generated inaccurate or even unsafe results.Therefore,it was necessary to find a new correction method for complex reactions.In this work,esterification of acetic anhydride by methanol was chosen as an object reaction of study.The reaction was studied under different conditions by Reaction Calorimeter(RC1).Then,Thermal Safety Software(TSS)was used to establish the kinetic model and estimate the parameters,where,activation energies for three stages were67.09,81.02,73.77 kJ?mol^(-1)respectively,and corresponding frequency factors in logarithmic form were 16.05,19.59,15.72 s^(-1).In addition,two adiabatic tests were performed by Vent Sizing Package2(VSP2).For accurate correction of VSP2 tests,a new correction method based on Enhanced Fisher method was proposed.Combined with kinetics,adiabatic correction of esterification reaction was achieved.Through this research,accurate kinetic parameters for a three-step kinetic model of the esterification reaction were acquired.Furthermore,the correlation coefficients between simulated curves and corrected curves were 0.976 and 0.968,which proved the accuracy of proposed new adiabatic correction method.Based on this new method,conservative corrected results were able to be acquired and be applied in safety assessment.
文摘The potential energy curves (PECs) of three low-lying electronic states (X^3∑, a^1△, and a^3△) of SO radical have been studied by ab initio quantum chemical method. The calcula- tions were carried out with the full valence complete active space self-consistent field method followed by the highly accurate valence internally contracted multireference configuration in- teraction (MRCI) approach in combination with correlation-consistent basis sets. Effects of the core-valence correlation and relativistic corrections on the PECs are taken into account. The core-valence correlation correction is carried out with the cc-pCVDZ basis set. The way to consider the relativistic correction is to use the second-order Douglas-Kroll Hamiltonian approximation, and the correction is performed at the level of cc-pV5Z basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are also corrected for size-extensivity errors by means of the Davidson modification (MRCI+Q). These PECs are extrapolated to the complete basis set limit by the two-point energy extrapolation scheme. With these PECs, the spectroscopic parameters are determined.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11675139,11605137,11435006,11405130the Double First-Class University Construction Project of Northwest University+1 种基金the China Postdoctoral Science Foundation under Grant No.2017M623219Shaanxi Postdoctoral Science Foundation
文摘By adopting a result from generalized uncertainty principles (GUP), we modify the inner bound of the membrane model to a physical fixed value and get the cut-offs naturally rather than by hand, which are both in brickwall model and membrane model, and the semi-classical quantization condition could always be valid as well. We also calculate the entropies of Schwarzschild-de Sitter black hole and find the GUP we choose qualitatively shows that the requirement of mass in this method is the same as the natural requirement of the Schwarzschild-de Sitter black hole,which means the method might be self-consistent.