The problem of a mode-II crack interface of two bonded dissimilar materials close to and perpendicular to an imperfect is investigated. The imperfect interface is modelled by a linear spring with the vanishing thickne...The problem of a mode-II crack interface of two bonded dissimilar materials close to and perpendicular to an imperfect is investigated. The imperfect interface is modelled by a linear spring with the vanishing thickness. The Fourier transform is used to solve the boundary-value problem and to derive a singular integral equation with the Cauchy kernel. The stress intensity factors near the left and right crack tips are evaluated by numerically solving the resulting equation. SeverM special cases of the mode-II crack problem with an imperfect interface are studied in detail. The effects of the interfacial imperfection on the stress intensity factors for a bimaterial system of aluminum and steel are shown graphically. The obtained observation reveals that the stress intensity factors are dependent on the interface parameters and vary between those with a fully debonded interface and those with a perfect interface.展开更多
To copy natural photosynthesis process we need to understand and explain the physics underneath its first step mechanism, which is “how to separate electrical charges under attraction”. But this Nature’s nanotechno...To copy natural photosynthesis process we need to understand and explain the physics underneath its first step mechanism, which is “how to separate electrical charges under attraction”. But this Nature’s nanotechnological creation is not yet available to the scientific community. We present a new interpretation for the artificial and natural photosynthetic mechanism, concerning the electrical charges separation and the spent energy to promote the process. Interface (e–, h+) recombination and emission is applied to explain the photosynthetic mechanisms. This interpretation is based on energy bands relative position, the staggered one, which under illumination promotes (e–, h+) charges separation through the action of an interface electric field and energy consumption at the interface of both A/B generic materials. Energy band bending is responsible by the interface electric field (and the driving force) for the charges separation. This electric field can be as high or above that for p-n semiconductor junctions (104 - 105 V/cm). This physical effect is not considered by most of the researches. Without an electric field and without spending energy to separate electrical charges, any other existing model violates physical laws. The staggered energy band type is the only energetic configuration that permits charges separation under illumination and energy loss to perform the process. Application to natural photosynthesis and artificial photovoltaic material and their energetic configurations are discussed. Examples for A/B being III-V/III-V, TiO2/materials and II-VI/II-VI staggered energy band gap pairs are presented. In the proposed quantum mechanism, plants are able to eliminate most of the 79% of the absorbed visible light, according to the published reflection and transmission data. Moreover, the proposed mechanism can be applied to explain green fluorescent protein - GFP, charge transfer states - CTS and Fluorescent Resonance Energy Transfer - FRET. As recent literature experimental results propose phot展开更多
The phase transition of superfluid helium (He II) to normal fluid helium (He I) is studied in this note. The He II -He I interface is found to move upwards under finite heat current. The temperature tracks are measure...The phase transition of superfluid helium (He II) to normal fluid helium (He I) is studied in this note. The He II -He I interface is found to move upwards under finite heat current. The temperature tracks are measured by four high resolution temperature sensors (HRTs). And the shifting of the λ point temperature (phase transition temperature) along the cell is studied experimentally and theoretically. Under gravity, the shifting of the λ point temperature in-creases with the pressure. The experimental results agree well with the theoretical ones.展开更多
基金supported by the National Natural Science Foundation of China (No. 90815001)the Natural Science Foundation of Guangxi Province of China (No. 2011GXNSFA018132)the Scientific Research Foundation of Guangxi University (No. XBZ111497)
文摘The problem of a mode-II crack interface of two bonded dissimilar materials close to and perpendicular to an imperfect is investigated. The imperfect interface is modelled by a linear spring with the vanishing thickness. The Fourier transform is used to solve the boundary-value problem and to derive a singular integral equation with the Cauchy kernel. The stress intensity factors near the left and right crack tips are evaluated by numerically solving the resulting equation. SeverM special cases of the mode-II crack problem with an imperfect interface are studied in detail. The effects of the interfacial imperfection on the stress intensity factors for a bimaterial system of aluminum and steel are shown graphically. The obtained observation reveals that the stress intensity factors are dependent on the interface parameters and vary between those with a fully debonded interface and those with a perfect interface.
文摘To copy natural photosynthesis process we need to understand and explain the physics underneath its first step mechanism, which is “how to separate electrical charges under attraction”. But this Nature’s nanotechnological creation is not yet available to the scientific community. We present a new interpretation for the artificial and natural photosynthetic mechanism, concerning the electrical charges separation and the spent energy to promote the process. Interface (e–, h+) recombination and emission is applied to explain the photosynthetic mechanisms. This interpretation is based on energy bands relative position, the staggered one, which under illumination promotes (e–, h+) charges separation through the action of an interface electric field and energy consumption at the interface of both A/B generic materials. Energy band bending is responsible by the interface electric field (and the driving force) for the charges separation. This electric field can be as high or above that for p-n semiconductor junctions (104 - 105 V/cm). This physical effect is not considered by most of the researches. Without an electric field and without spending energy to separate electrical charges, any other existing model violates physical laws. The staggered energy band type is the only energetic configuration that permits charges separation under illumination and energy loss to perform the process. Application to natural photosynthesis and artificial photovoltaic material and their energetic configurations are discussed. Examples for A/B being III-V/III-V, TiO2/materials and II-VI/II-VI staggered energy band gap pairs are presented. In the proposed quantum mechanism, plants are able to eliminate most of the 79% of the absorbed visible light, according to the published reflection and transmission data. Moreover, the proposed mechanism can be applied to explain green fluorescent protein - GFP, charge transfer states - CTS and Fluorescent Resonance Energy Transfer - FRET. As recent literature experimental results propose phot
基金The research was jointly supported by the National Natural Science Foundation of China (Grant No. 59876018) the Ministry of Education, the Education Committee of Shanghai and Shanghai Sci. & Tech. Young Star Program (Grant No. 01QF4027) The part of t
文摘The phase transition of superfluid helium (He II) to normal fluid helium (He I) is studied in this note. The He II -He I interface is found to move upwards under finite heat current. The temperature tracks are measured by four high resolution temperature sensors (HRTs). And the shifting of the λ point temperature (phase transition temperature) along the cell is studied experimentally and theoretically. Under gravity, the shifting of the λ point temperature in-creases with the pressure. The experimental results agree well with the theoretical ones.
