FeCrAl(f)/HA biological functionally gradient materials(FGMs) were successfully fabricated by the hot pressing technique.Scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and bending strength test ...FeCrAl(f)/HA biological functionally gradient materials(FGMs) were successfully fabricated by the hot pressing technique.Scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and bending strength test machine were utilized to characterize the microstructure,component,mechanical properties and the formation of the Ca-deficient apatite on the surface of these materials.The results indicate that an asymmetrical FeCrAl(f)/HA FGM,consolidating powders prepared by mixing HA with 3%–15%(volume fraction) is successfully prepared.Both of the matrix and FeCrAl fiber are integrated very tightly and bite into each other very deeply.And counter diffusion takes place to some extent in two phase interfaces.The elemental compositions of the FeCrAl(f)/HA FGM change progressively.Ca and P contents increase gradually with immersion time increasing,and thereafter approach equilibrium.The bone-like apatite layer forms on the materials surface,which possesses benign bioactivity,and the favorable biocompatibility can provide potential firm fixation between FeCrAl(f)/HA asymmetrical FGM implants and human bone.展开更多
Insecurity and asymmetry in all their ramifications are ideological. They are also inherently communicative processes that are largely constructed and enacted through language in various institutional discourses. In U...Insecurity and asymmetry in all their ramifications are ideological. They are also inherently communicative processes that are largely constructed and enacted through language in various institutional discourses. In Urhobo, sex proverbs copiously couch the ideological conceptualizations of the male-female biological asymmetry. Studies on Urhobo proverbs dwell largely on functional applications and documentations of the proverbs, thereby overlooking their ideological underpinnings. Therefore, in this paper, efforts are geared toward investigating and unravelling ideologies that have been habitualized in the semantic and pragmatic structures of the Urhobo sex proverbs. The intention is to throw open the patterns of relationship between the male and female participants in the society in relation to sex matters and power. Twenty-six Urhobo indigenes （six males and 20 females）, who are competent in the socioculture and language were successfully interviewed to elicit Urhobo sex proverbs. Proverbs that contain the following lexical items： penis, virgina, to make love, or to have sex are purposively selected and subjected to CDA （critical discourse analysis）. The main assumption of CDA is that language is both the site and the stake in the struggle for power and domination. Findings show that in the Urhobo sex proverbs, there is asymmetry in access to sexual relations between the male and female. Although the sex proverbs do not always refer to copulation, they are often employed as powerful instruments to dominate and instil fear in the female participant. Consequently, patriarchal discourses are further entrenched in the society展开更多
The Noether and Lie symmetries as well as the conserved quantities of Hamiltonian system with fractional derivatives are es-tablished. The definitions and criteria for the fractional symmetrical transformations and qu...The Noether and Lie symmetries as well as the conserved quantities of Hamiltonian system with fractional derivatives are es-tablished. The definitions and criteria for the fractional symmetrical transformations and quasi-symmetrical transformations inthe Noether sense of Hamiltonian system are first discussed. Then, using the invariance of Hamiltonian action under the infini-tesimal transformations with respect to time, generalized coordinates and generalized momentums, the fractional Noethertheorem of the system is obtained. Further, the Lie symmetry and conserved quantity of the system are acquired. Two exam-ples are presented to illustrate the application of the results.展开更多
We investigate a generalized form of the Boussinesq equation, relevant for nerve pulse propagation in biological membranes. The generalized conditional symmetry （GCS） method is applied in order to obtain the conditi...We investigate a generalized form of the Boussinesq equation, relevant for nerve pulse propagation in biological membranes. The generalized conditional symmetry （GCS） method is applied in order to obtain the conditions that enable the equation to admit a special class of second-order GCSs. For the case of quadratic nonlinearities, we outline a new class of invariant solutions.展开更多
基金Project(51274247)supported by the National Natural Science Foundation of ChinaProject(2012BAE06B00)supported by the National High Technology Research and Development Program to China+1 种基金Project(2011QNZT046)supported by the Fundamental Research Funds of Central South Universities of ChinaProject supported by Hunan Postdoctoral Scientific Program,China
文摘FeCrAl(f)/HA biological functionally gradient materials(FGMs) were successfully fabricated by the hot pressing technique.Scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and bending strength test machine were utilized to characterize the microstructure,component,mechanical properties and the formation of the Ca-deficient apatite on the surface of these materials.The results indicate that an asymmetrical FeCrAl(f)/HA FGM,consolidating powders prepared by mixing HA with 3%–15%(volume fraction) is successfully prepared.Both of the matrix and FeCrAl fiber are integrated very tightly and bite into each other very deeply.And counter diffusion takes place to some extent in two phase interfaces.The elemental compositions of the FeCrAl(f)/HA FGM change progressively.Ca and P contents increase gradually with immersion time increasing,and thereafter approach equilibrium.The bone-like apatite layer forms on the materials surface,which possesses benign bioactivity,and the favorable biocompatibility can provide potential firm fixation between FeCrAl(f)/HA asymmetrical FGM implants and human bone.
文摘Insecurity and asymmetry in all their ramifications are ideological. They are also inherently communicative processes that are largely constructed and enacted through language in various institutional discourses. In Urhobo, sex proverbs copiously couch the ideological conceptualizations of the male-female biological asymmetry. Studies on Urhobo proverbs dwell largely on functional applications and documentations of the proverbs, thereby overlooking their ideological underpinnings. Therefore, in this paper, efforts are geared toward investigating and unravelling ideologies that have been habitualized in the semantic and pragmatic structures of the Urhobo sex proverbs. The intention is to throw open the patterns of relationship between the male and female participants in the society in relation to sex matters and power. Twenty-six Urhobo indigenes （six males and 20 females）, who are competent in the socioculture and language were successfully interviewed to elicit Urhobo sex proverbs. Proverbs that contain the following lexical items： penis, virgina, to make love, or to have sex are purposively selected and subjected to CDA （critical discourse analysis）. The main assumption of CDA is that language is both the site and the stake in the struggle for power and domination. Findings show that in the Urhobo sex proverbs, there is asymmetry in access to sexual relations between the male and female. Although the sex proverbs do not always refer to copulation, they are often employed as powerful instruments to dominate and instil fear in the female participant. Consequently, patriarchal discourses are further entrenched in the society
基金supported by the National Natural Science Foundation of China (Grant No. 11072218)
文摘The Noether and Lie symmetries as well as the conserved quantities of Hamiltonian system with fractional derivatives are es-tablished. The definitions and criteria for the fractional symmetrical transformations and quasi-symmetrical transformations inthe Noether sense of Hamiltonian system are first discussed. Then, using the invariance of Hamiltonian action under the infini-tesimal transformations with respect to time, generalized coordinates and generalized momentums, the fractional Noethertheorem of the system is obtained. Further, the Lie symmetry and conserved quantity of the system are acquired. Two exam-ples are presented to illustrate the application of the results.
文摘We investigate a generalized form of the Boussinesq equation, relevant for nerve pulse propagation in biological membranes. The generalized conditional symmetry （GCS） method is applied in order to obtain the conditions that enable the equation to admit a special class of second-order GCSs. For the case of quadratic nonlinearities, we outline a new class of invariant solutions.
