Internal stresses in glass are generated by interactions between thermal contraction, elasticity at low tem-peratures, viscoelastic flow at higher temperature, and temperature gradients caused by cooling. This work in...Internal stresses in glass are generated by interactions between thermal contraction, elasticity at low tem-peratures, viscoelastic flow at higher temperature, and temperature gradients caused by cooling. This work intends to work out calculation program for real temperature distribution and internals stress, and to study their behaviour during the quenching through a flat plate of soda-lime glass from different temperatures.展开更多
The effects of internal stresses and depolarization fields on the properties of epitaxial ferroelectric perovskite thin films are discussed by employing the dynamic Ginzbur~Landau equation （DCLE）. The numerical solu...The effects of internal stresses and depolarization fields on the properties of epitaxial ferroelectric perovskite thin films are discussed by employing the dynamic Ginzbur~Landau equation （DCLE）. The numerical solution for BaTiO3 film shows that internal stress and the depolarization field have the most effects on ferroelectric properties such as polarization, Curie temperature and susceptibility. With the increase of the thickness of the film, the polarization of epitaxia] ferroelectric thin film is enhanced rapidly under high internal compressively stress. With the thickness exceeding the critical thickness for dislocation formation, the polarization increases slowly and even weakens due to relaxed internal stresses and a weak electrical boundary condition. This indicates that the effects of mechanical and electrical boundary conditions both diminish for ferroelectric thick films. Consequently, our thermodynamic method is a full scale model that can predict the properties of ferroelectric perovskite films in a wide range of film thickness.展开更多
A physical and mathematical model of the transition from a discrete model of linear and flat defects nuclei to continuum models of defects such as dislocations and disclinations and their combinations is presented, wh...A physical and mathematical model of the transition from a discrete model of linear and flat defects nuclei to continuum models of defects such as dislocations and disclinations and their combinations is presented, where the tensors of energy-momentum and angular momentum of an alternating field are considered, for which the type and structure of the Maxwell stress tensor <span><i>σ</i></span><sup><i>if</i></sup><sub style="margin-left:-15px;"> <i>αβ</i></sub> are given and the corresponding angular momentum tensor, using the dynamic equation for the evolution of internal stresses and the correlation between the stresses <span><i>σ</i></span><sup><i>if</i></sup><sub style="margin-left:-15px;"> <i>αβ</i></sub> in the defect core and the elastic stresses <span><i>σ</i></span><sup><i>el</i></sup><sub style="margin-left:-9px;"><i>ik</i></sub> in its environment, obtains elastic displacement and deformation fields identical to these fields from Burgers and Frank vectors of continuous models. The spectral density of the autocorrelation functions of the velocity of photoelectrons <span>Ψ</span><sup><i>β</i></sup><sub style="margin-left:-6px;">⊥</sub>(<i>β</i>) and cations <img src="Edit_e2d8e074-eb94-44dc-8ab6-6644bbf74f9c.bmp" alt="" /> , which transforms into linear spectra as <i>T</i> → 0, is considered reflecting the existence of threshold values of oscillation and rotations currents of photoelectrons and cations at all stages of plastic deformation and fracture. The features of the process of sliding linear defects in metals are disclosed.展开更多
The principle, formula and determination of internal stresses of metal multilayer composite coatings by means of the bending strip method were studied. Using this method, internal stresses of ion-plated metal multila... The principle, formula and determination of internal stresses of metal multilayer composite coatings by means of the bending strip method were studied. Using this method, internal stresses of ion-plated metal multilayer composite coatings and thick monolayer coating of aluminium bronze, stainless steel and nickel-iron alloy were determined. The reason of decrement in internal stresses of multilayer composite coatings was discussed.展开更多
文摘Internal stresses in glass are generated by interactions between thermal contraction, elasticity at low tem-peratures, viscoelastic flow at higher temperature, and temperature gradients caused by cooling. This work intends to work out calculation program for real temperature distribution and internals stress, and to study their behaviour during the quenching through a flat plate of soda-lime glass from different temperatures.
基金Project supported by the National Natural Science Foundation of China （Grant Nos. 10802070, 10972188, and 10902055）, Natural Science Foundation of Fujian Province of China （Grant No. 2011J01329）, and the Fundamental Research Funds for the Central Universities of China （Grant No. 2011121002）.
文摘The effects of internal stresses and depolarization fields on the properties of epitaxial ferroelectric perovskite thin films are discussed by employing the dynamic Ginzbur~Landau equation （DCLE）. The numerical solution for BaTiO3 film shows that internal stress and the depolarization field have the most effects on ferroelectric properties such as polarization, Curie temperature and susceptibility. With the increase of the thickness of the film, the polarization of epitaxia] ferroelectric thin film is enhanced rapidly under high internal compressively stress. With the thickness exceeding the critical thickness for dislocation formation, the polarization increases slowly and even weakens due to relaxed internal stresses and a weak electrical boundary condition. This indicates that the effects of mechanical and electrical boundary conditions both diminish for ferroelectric thick films. Consequently, our thermodynamic method is a full scale model that can predict the properties of ferroelectric perovskite films in a wide range of film thickness.
文摘A physical and mathematical model of the transition from a discrete model of linear and flat defects nuclei to continuum models of defects such as dislocations and disclinations and their combinations is presented, where the tensors of energy-momentum and angular momentum of an alternating field are considered, for which the type and structure of the Maxwell stress tensor <span><i>σ</i></span><sup><i>if</i></sup><sub style="margin-left:-15px;"> <i>αβ</i></sub> are given and the corresponding angular momentum tensor, using the dynamic equation for the evolution of internal stresses and the correlation between the stresses <span><i>σ</i></span><sup><i>if</i></sup><sub style="margin-left:-15px;"> <i>αβ</i></sub> in the defect core and the elastic stresses <span><i>σ</i></span><sup><i>el</i></sup><sub style="margin-left:-9px;"><i>ik</i></sub> in its environment, obtains elastic displacement and deformation fields identical to these fields from Burgers and Frank vectors of continuous models. The spectral density of the autocorrelation functions of the velocity of photoelectrons <span>Ψ</span><sup><i>β</i></sup><sub style="margin-left:-6px;">⊥</sub>(<i>β</i>) and cations <img src="Edit_e2d8e074-eb94-44dc-8ab6-6644bbf74f9c.bmp" alt="" /> , which transforms into linear spectra as <i>T</i> → 0, is considered reflecting the existence of threshold values of oscillation and rotations currents of photoelectrons and cations at all stages of plastic deformation and fracture. The features of the process of sliding linear defects in metals are disclosed.
文摘 The principle, formula and determination of internal stresses of metal multilayer composite coatings by means of the bending strip method were studied. Using this method, internal stresses of ion-plated metal multilayer composite coatings and thick monolayer coating of aluminium bronze, stainless steel and nickel-iron alloy were determined. The reason of decrement in internal stresses of multilayer composite coatings was discussed.
