Explaining the mechanism of the cochlear active phonosensitive amplification has been a major problem in medicine.The basilar membrane(BM)is the key infrastructure.In 1960,Nobel Laureate von B′ek′esy first discovere...Explaining the mechanism of the cochlear active phonosensitive amplification has been a major problem in medicine.The basilar membrane(BM)is the key infrastructure.In 1960,Nobel Laureate von B′ek′esy first discovered BM's traveling wave motion.Since that time,BM's models only have considered the traveling wave but not the biological activity.Therefore,a new model considering changes of BM's stiffness in space and time is established based on the immersed boundary method to describe its biological activity.It not only reproduces the results of traveling wave motion but also explains the mechanization on the generation of traveling wave.An important discovery is that changes of BM's stiffness in space and time will cause the unstable global resonance,which will induce amplification of sounds in cochlea.An important inference is that biological activity shall be included in the application of mechanical principles to the analysis of life,which is the essential difference between biomechanics and general mechanics.展开更多
According to the vibration characteristics of the round window, a mechani- cal model of a round window membrane is established. The Euler equation of the round window and the complementary boundary conditions are deri...According to the vibration characteristics of the round window, a mechani- cal model of a round window membrane is established. The Euler equation of the round window and the complementary boundary conditions are derived by the variational prin- ciple. Combined with the Bessel function, an analytical solution of the round window displacement is obtained by MATHEMATICA. Combined with clinical characteristics of round window membrane lesion, the effect of sound transmission due to thickening of the round window membrane caused by the otitis media, shrinkage of the round window membrane area caused by otosclerosis, and hardening of the round window membrane itself is analyzed. The results show that with thickening of the round window membrane, the displacement of the round window membrane is decreased. In the meantime, with hardening of the round window membrane and shrinkage of the membrane area, the max- imum displacement Of the round window membrane is gradually reduced, leading to a decrease in sound transmission. Thus, the analyticM analysis can avoid interference of environment and the technical level of personnel, and it can evaluate transmission per- formance of the round window membrane efficiently, providing a theoretical basis for the reverse excitation of artificial prosthesis.展开更多
In this paper, the effect of fluid in a tunnel of Corti (TC) on organ of Corti (OC) is studied. A three-dimensional OC model including basilar membrane (BM), tectorial membrane (TM), inner and outer hair cells...In this paper, the effect of fluid in a tunnel of Corti (TC) on organ of Corti (OC) is studied. A three-dimensional OC model including basilar membrane (BM), tectorial membrane (TM), inner and outer hair cells (OHCs), and reticular lamina (RL) is established by COMSOL. An initial pressure is applied to the fluid in the TC. The frequency response of the structure is analyzed, and the displacement of the BM is achieved. The results are in good agreement with the experimental data, confirming validity of the finite element model. Based on the model, the effect of fluid in the TC on the OC is studied. The results show that, when the pressure gradient is absent in the fluid, with the increase of the initial fluid pressure, the displacement of the BM increases. However, when the initial fluid pressure increases to a certain value, the increase rate of the displacement of the BM becomes very slow. The movement of the fluid amplifies the BM movement. Furthermore, the movement of the fluid can strengthen the movement of the OHCs and the shear movement of the stereocilia, especially in the vicinity of the characteristic frequency at which the amplification effect reaches a peak. Nevertheless, a pressure gradient in the fluid affects the BM movement.展开更多
A three-dimensional inner stereocilium model is established by PATRAN. According to the relevant data, the corresponding pressure is applied to one side of the inner stereocilia. The top displacement of the inner ster...A three-dimensional inner stereocilium model is established by PATRAN. According to the relevant data, the corresponding pressure is applied to one side of the inner stereocilia. The top displacement of the inner stereocilia along the cross section of the basilar membrane (the x-displacement) is similar to the available data in the literature, which verifies the correctness of the model. Based on Castigliano's theorem, the displacement of a single stereocilium is achieved under the inverted triangle force. The results are in good agreement with the data obtained from the finite element (FE) model, which confirms the validity of the formula. With the FE model, the effects of the movement of the hair cells and fluid in the cochlear duct on the x-displacements of the inner stereocilia are studied. The results show that the movement of the hair cells affects the x-displacements of the inner stereocilia, especially for the shortest stereocilium, and the fluid in the cochlear duct affects the x-displacements of the inner stereocilia, especially for the middle stereocilium. Moreover, compared with the effects of the hair cells on the stereocilia, the effect of the cochlear duct fluid is greater.展开更多
According to the vibration characteristics of the organ of Corti (OC), seven hypotheses are made to simplify the structure of the model, and a mechanical OC model is established. Using the variational principle, a d...According to the vibration characteristics of the organ of Corti (OC), seven hypotheses are made to simplify the structure of the model, and a mechanical OC model is established. Using the variational principle, a displacement analytical expression is solved under a certain pressure. The results are in good agreement with experimental data, showing the validity of the formula. Combined with the damage caused by noise in clinic, it is found that the hardening of outer hair cells and outer stereocilia can lead to loss of hearing and generation of threshold shift. In addition, the results show that high frequency resonance occurs at the bottom of the basilar membrane (BM), and low frequency resonance occurs at the top of the BM. This confirms the frequency selective characteristics of the BM. Further, using this formula can avoid interference of the envi- ronment and the technical level of the test personnel, and can evaluate performance of the OC objectively.展开更多
The materials with different moduli in tension and compression are called bi-modulus materials. Graphene is such a kind of materials with the highest strength and the thinnest thickness. In this paper, the mechanical ...The materials with different moduli in tension and compression are called bi-modulus materials. Graphene is such a kind of materials with the highest strength and the thinnest thickness. In this paper, the mechanical response of the bi-modulus beam subjected to the temperature effect and placed on the Winkler foundation is studied. The differential equations about the neutral axis position and undetermined parameters of the normal strain of the bi-modulus foundation beam are established. Then, the analytical expressions of the normal stress, bending moment, and displacement of the foundation beam are derived. Simultaneously, a calculation procedure based on the finite element method (FEM) is developed to obtain the temperature stress of the bi-modulus struc- tures. It is shown that the obtained bi-modulus solutions can recover the classical modulus solution, and the results obtained by the analytical expressions, the present FEM proce- dure, and the traditional FEM software are consistent, which verifies the accuracy and reliability of the present analytical model and procedure. Finally, the difference between the bi-modulus results and the classical same modulus results is discussed, and several reasonable suggestions for calculating and optimizing the certain bi-modulus member in practical engineering are presented.展开更多
In this paper,we propose a new non-local diffusion equation for noise removal,which is derived from the classical Perona-Malik equation(PM equation)and the regularized PM equation.Using the convolution of the image gr...In this paper,we propose a new non-local diffusion equation for noise removal,which is derived from the classical Perona-Malik equation(PM equation)and the regularized PM equation.Using the convolution of the image gradient and the gradient,we propose a new diffusion coefficient.Due to the use of the convolution,the diffusion coefficient is non-local.However,the solution of the new diffusion equation may be discontinuous and belong to the bounded variation space(BV space).By virtue of Young measure method,the existence of a BV solution to the new non-local diffusion equation is established.Experimental results illustrate that the new method has some non-local performance and performs better than the original PM and other methods.展开更多
基金Project supported by the Key Projects of National Natural Science Foundation of China(No.11932010)。
文摘Explaining the mechanism of the cochlear active phonosensitive amplification has been a major problem in medicine.The basilar membrane(BM)is the key infrastructure.In 1960,Nobel Laureate von B′ek′esy first discovered BM's traveling wave motion.Since that time,BM's models only have considered the traveling wave but not the biological activity.Therefore,a new model considering changes of BM's stiffness in space and time is established based on the immersed boundary method to describe its biological activity.It not only reproduces the results of traveling wave motion but also explains the mechanization on the generation of traveling wave.An important discovery is that changes of BM's stiffness in space and time will cause the unstable global resonance,which will induce amplification of sounds in cochlea.An important inference is that biological activity shall be included in the application of mechanical principles to the analysis of life,which is the essential difference between biomechanics and general mechanics.
基金Project supported by the National Natural Science Foundation of China(Nos.11272200 and11572186)
文摘According to the vibration characteristics of the round window, a mechani- cal model of a round window membrane is established. The Euler equation of the round window and the complementary boundary conditions are derived by the variational prin- ciple. Combined with the Bessel function, an analytical solution of the round window displacement is obtained by MATHEMATICA. Combined with clinical characteristics of round window membrane lesion, the effect of sound transmission due to thickening of the round window membrane caused by the otitis media, shrinkage of the round window membrane area caused by otosclerosis, and hardening of the round window membrane itself is analyzed. The results show that with thickening of the round window membrane, the displacement of the round window membrane is decreased. In the meantime, with hardening of the round window membrane and shrinkage of the membrane area, the max- imum displacement Of the round window membrane is gradually reduced, leading to a decrease in sound transmission. Thus, the analyticM analysis can avoid interference of environment and the technical level of personnel, and it can evaluate transmission per- formance of the round window membrane efficiently, providing a theoretical basis for the reverse excitation of artificial prosthesis.
基金Project supported by the National Natural Science Foundation of China(Nos.11272200 and 11572186)
文摘In this paper, the effect of fluid in a tunnel of Corti (TC) on organ of Corti (OC) is studied. A three-dimensional OC model including basilar membrane (BM), tectorial membrane (TM), inner and outer hair cells (OHCs), and reticular lamina (RL) is established by COMSOL. An initial pressure is applied to the fluid in the TC. The frequency response of the structure is analyzed, and the displacement of the BM is achieved. The results are in good agreement with the experimental data, confirming validity of the finite element model. Based on the model, the effect of fluid in the TC on the OC is studied. The results show that, when the pressure gradient is absent in the fluid, with the increase of the initial fluid pressure, the displacement of the BM increases. However, when the initial fluid pressure increases to a certain value, the increase rate of the displacement of the BM becomes very slow. The movement of the fluid amplifies the BM movement. Furthermore, the movement of the fluid can strengthen the movement of the OHCs and the shear movement of the stereocilia, especially in the vicinity of the characteristic frequency at which the amplification effect reaches a peak. Nevertheless, a pressure gradient in the fluid affects the BM movement.
基金supported by the National Natural Science Foundation of China(Nos.11272200 and 11572186)
文摘A three-dimensional inner stereocilium model is established by PATRAN. According to the relevant data, the corresponding pressure is applied to one side of the inner stereocilia. The top displacement of the inner stereocilia along the cross section of the basilar membrane (the x-displacement) is similar to the available data in the literature, which verifies the correctness of the model. Based on Castigliano's theorem, the displacement of a single stereocilium is achieved under the inverted triangle force. The results are in good agreement with the data obtained from the finite element (FE) model, which confirms the validity of the formula. With the FE model, the effects of the movement of the hair cells and fluid in the cochlear duct on the x-displacements of the inner stereocilia are studied. The results show that the movement of the hair cells affects the x-displacements of the inner stereocilia, especially for the shortest stereocilium, and the fluid in the cochlear duct affects the x-displacements of the inner stereocilia, especially for the middle stereocilium. Moreover, compared with the effects of the hair cells on the stereocilia, the effect of the cochlear duct fluid is greater.
基金Project supported by the National Natural Science Foundation of China(Nos.11272200 and11572186)
文摘According to the vibration characteristics of the organ of Corti (OC), seven hypotheses are made to simplify the structure of the model, and a mechanical OC model is established. Using the variational principle, a displacement analytical expression is solved under a certain pressure. The results are in good agreement with experimental data, showing the validity of the formula. Combined with the damage caused by noise in clinic, it is found that the hardening of outer hair cells and outer stereocilia can lead to loss of hearing and generation of threshold shift. In addition, the results show that high frequency resonance occurs at the bottom of the basilar membrane (BM), and low frequency resonance occurs at the top of the BM. This confirms the frequency selective characteristics of the BM. Further, using this formula can avoid interference of the envi- ronment and the technical level of the test personnel, and can evaluate performance of the OC objectively.
基金supported by the National Natural Science Foundation of China(Nos.11072143 and11272200)
文摘The materials with different moduli in tension and compression are called bi-modulus materials. Graphene is such a kind of materials with the highest strength and the thinnest thickness. In this paper, the mechanical response of the bi-modulus beam subjected to the temperature effect and placed on the Winkler foundation is studied. The differential equations about the neutral axis position and undetermined parameters of the normal strain of the bi-modulus foundation beam are established. Then, the analytical expressions of the normal stress, bending moment, and displacement of the foundation beam are derived. Simultaneously, a calculation procedure based on the finite element method (FEM) is developed to obtain the temperature stress of the bi-modulus struc- tures. It is shown that the obtained bi-modulus solutions can recover the classical modulus solution, and the results obtained by the analytical expressions, the present FEM proce- dure, and the traditional FEM software are consistent, which verifies the accuracy and reliability of the present analytical model and procedure. Finally, the difference between the bi-modulus results and the classical same modulus results is discussed, and several reasonable suggestions for calculating and optimizing the certain bi-modulus member in practical engineering are presented.
基金partially supported by the National Natural Science Foundation of China(11971131,12171123,11871133,11671111,U1637208,61873071,51476047)the Guangdong Basic and Applied Basic Research Foundation(2020B1515310006)+1 种基金the Natural Sciences Foundation of Heilongjiang Province(LH2021A011)China Postdoctoral Science Foundation(2020M670893).
文摘In this paper,we propose a new non-local diffusion equation for noise removal,which is derived from the classical Perona-Malik equation(PM equation)and the regularized PM equation.Using the convolution of the image gradient and the gradient,we propose a new diffusion coefficient.Due to the use of the convolution,the diffusion coefficient is non-local.However,the solution of the new diffusion equation may be discontinuous and belong to the bounded variation space(BV space).By virtue of Young measure method,the existence of a BV solution to the new non-local diffusion equation is established.Experimental results illustrate that the new method has some non-local performance and performs better than the original PM and other methods.