The influence of the surface effect on the nanosized spherical void growth in a rigidperfectly plastic material is analyzed and the mechanism of the nanosized void growth with high triaxiality is given. Based on the R...The influence of the surface effect on the nanosized spherical void growth in a rigidperfectly plastic material is analyzed and the mechanism of the nanosized void growth with high triaxiality is given. Based on the Rice and Tracey model for a macro void growth, the present model is proposed to account for the nanosized void growth under a uniform remote strain rate field with consideration on the surface effect. It is concluded that the surface effect yields an evident resistant influence on the nanosized void growth. That is, this influence decays as the void radius increases. With high triaxiality, the nanosized void growth is divided into two stages： the initial stage and the mature stage. At the first stage, the void grows slowly and the influence of surface effect is relatively weak, whereas at the second stage, the influence is significant and the void grows drastically.展开更多
A continuum model of solids with cylindrical microvoids is proposed based on the Taylor dislocation model. The model is an extension of Gurson model in the sense that the void size effect is accounted for. Beside the ...A continuum model of solids with cylindrical microvoids is proposed based on the Taylor dislocation model. The model is an extension of Gurson model in the sense that the void size effect is accounted for. Beside the void volume fraction f, the intrinsic material length l becomes a parameter representing voids since the void size comes into play in the Gurson model. Approximate yield functions in analytic forms are suggested for both solids with cylindrical microvoids and with spherical microvoids. The application to uniaxial tension curves shows a precise agreement between the approximate analytic yield function and the exact parametric form of integrals.展开更多
The combined effects of void size and void shape on the void growth are studied by using the classical spectrum method. An infinite solid containing an isolated prolate spheroidal void is considered to depict the void...The combined effects of void size and void shape on the void growth are studied by using the classical spectrum method. An infinite solid containing an isolated prolate spheroidal void is considered to depict the void shape effect and the Fleck-Hutchinson phenomenological strain gradient plasticity theory is employed to capture the size effects. It is found that the combined effects of void size and void shape are mainly controlled by the remote stress triaxiality. Based on this, a new size-dependent void growth model similar to the Rice-Tracey model is proposed and an important conclusion about the size-dependent void growth is drawn： the growth rate of the void with radius smaller than a critical radius rc may be ignored. It is interesting that rc. is a material constant independent of the initial void shape and the remote stress triaxiality.展开更多
This study aims at exploring the void space gas effect of earthquake-triggered slope instability and providing a new method for studying the formation mechanism of earthquake-triggered landslides. We analysed the basi...This study aims at exploring the void space gas effect of earthquake-triggered slope instability and providing a new method for studying the formation mechanism of earthquake-triggered landslides. We analysed the basic characteristics, kinematic characteristics, initiation mechanisms and physical mechanical parameters of the Daguangbao landslide, generalized a landslide prototype, and established a geological model and performed simulation tests. Based on the seismic wave propagation theory of rock-soil mass, rock fracture mechanics and the effective stress principle, we found that the void space gas effect is due to the occurrence of excess void space gas pressure when the dynamic response of seismic loads impacts the void space gas in weak intercalated layers of the slope. The excess void space gas pressure generated by the vibration(earthquake) damages the rock mass around the void space with a certain regularity. The model test results show that the effective shear strength of the rock mass can be reduced by 4.4% to 21.6% due to the void space gas effect.展开更多
The paper describes the instrumentation for studying temperature and void reactivity effects that were developed at VR-I zero power reactor. Further are described its operational parameters, fields and ways of its uti...The paper describes the instrumentation for studying temperature and void reactivity effects that were developed at VR-I zero power reactor. Further are described its operational parameters, fields and ways of its utilization as well as issues connected to its implementation into the reactor core.展开更多
We conduct several experiments to further clarify the formation mechanism of a self-organized void array induced by a single laser beam, including energy-related experiments, refractive-index-contrast-related experime...We conduct several experiments to further clarify the formation mechanism of a self-organized void array induced by a single laser beam, including energy-related experiments, refractive-index-contrast-related experiments, depth-related ex- periments, and effective-numerical-aperture experiment. These experiments indicate that the interface spherical aberration is indeed responsible for the formation of void arrays.展开更多
全无机钙钛矿量子点CsPbI_(3)拥有出色的光学性能,适用于红光的发光器件及太阳能电池领域。同时,组分原子半径相差较大,且软晶格导致卤素离子迁移,会导致CsPbI_(3)量子点发生相变,即失效。利用铅基金属有机框架(Pb metal organic framew...全无机钙钛矿量子点CsPbI_(3)拥有出色的光学性能,适用于红光的发光器件及太阳能电池领域。同时,组分原子半径相差较大,且软晶格导致卤素离子迁移,会导致CsPbI_(3)量子点发生相变,即失效。利用铅基金属有机框架(Pb metal organic framework,Pb-MOF)作为钙钛矿中的铅源,合成CsPbI_(3)量子点(CsPbI_(3)@Pb-MOF-OLAMI)。结果表明,其热稳定性提升了40%,而光照稳定性在经过碘化铅(PbI_(2))离子源溶液的修复后,提升了15倍。这种稳定性的改善主要源于孔洞限制效应,即Pb-MOF的多孔结构阻碍或减缓卤素离子的迁移,避免或减少缺陷的形成,也就抑制了钙钛矿变性过程。该研究为改善钙钛矿量子点CsPbI_(3)的稳定性提供了新思路。展开更多
基金the National Natural Science Foundation of China(No.10572110).
文摘The influence of the surface effect on the nanosized spherical void growth in a rigidperfectly plastic material is analyzed and the mechanism of the nanosized void growth with high triaxiality is given. Based on the Rice and Tracey model for a macro void growth, the present model is proposed to account for the nanosized void growth under a uniform remote strain rate field with consideration on the surface effect. It is concluded that the surface effect yields an evident resistant influence on the nanosized void growth. That is, this influence decays as the void radius increases. With high triaxiality, the nanosized void growth is divided into two stages： the initial stage and the mature stage. At the first stage, the void grows slowly and the influence of surface effect is relatively weak, whereas at the second stage, the influence is significant and the void grows drastically.
基金The project supported by the National Natural Science Foundation of China(20020003023)the Ministry of Education(key grant 0306)
文摘A continuum model of solids with cylindrical microvoids is proposed based on the Taylor dislocation model. The model is an extension of Gurson model in the sense that the void size effect is accounted for. Beside the void volume fraction f, the intrinsic material length l becomes a parameter representing voids since the void size comes into play in the Gurson model. Approximate yield functions in analytic forms are suggested for both solids with cylindrical microvoids and with spherical microvoids. The application to uniaxial tension curves shows a precise agreement between the approximate analytic yield function and the exact parametric form of integrals.
基金The project supported by the National Natural Science Foundation of China(A10102006)the New Century Excellent Talents in Universities of China.
文摘The combined effects of void size and void shape on the void growth are studied by using the classical spectrum method. An infinite solid containing an isolated prolate spheroidal void is considered to depict the void shape effect and the Fleck-Hutchinson phenomenological strain gradient plasticity theory is employed to capture the size effects. It is found that the combined effects of void size and void shape are mainly controlled by the remote stress triaxiality. Based on this, a new size-dependent void growth model similar to the Rice-Tracey model is proposed and an important conclusion about the size-dependent void growth is drawn： the growth rate of the void with radius smaller than a critical radius rc may be ignored. It is interesting that rc. is a material constant independent of the initial void shape and the remote stress triaxiality.
基金funded by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (No.SKLGP2016Z015)the Natural Science Foundation of China (No. 41572308)
文摘This study aims at exploring the void space gas effect of earthquake-triggered slope instability and providing a new method for studying the formation mechanism of earthquake-triggered landslides. We analysed the basic characteristics, kinematic characteristics, initiation mechanisms and physical mechanical parameters of the Daguangbao landslide, generalized a landslide prototype, and established a geological model and performed simulation tests. Based on the seismic wave propagation theory of rock-soil mass, rock fracture mechanics and the effective stress principle, we found that the void space gas effect is due to the occurrence of excess void space gas pressure when the dynamic response of seismic loads impacts the void space gas in weak intercalated layers of the slope. The excess void space gas pressure generated by the vibration(earthquake) damages the rock mass around the void space with a certain regularity. The model test results show that the effective shear strength of the rock mass can be reduced by 4.4% to 21.6% due to the void space gas effect.
文摘The paper describes the instrumentation for studying temperature and void reactivity effects that were developed at VR-I zero power reactor. Further are described its operational parameters, fields and ways of its utilization as well as issues connected to its implementation into the reactor core.
基金supported by the National Basic Research Program of China(Grant Nos.61205128,60908007,and 1102075)the Research Foundation for AdvancedTalents of Jiangsu University,China(Grant No.09JDG022)the Natural Science Foundation of Shanghai Municipal,China(Grant No.13ZR1414800)
文摘We conduct several experiments to further clarify the formation mechanism of a self-organized void array induced by a single laser beam, including energy-related experiments, refractive-index-contrast-related experiments, depth-related ex- periments, and effective-numerical-aperture experiment. These experiments indicate that the interface spherical aberration is indeed responsible for the formation of void arrays.
文摘全无机钙钛矿量子点CsPbI_(3)拥有出色的光学性能,适用于红光的发光器件及太阳能电池领域。同时,组分原子半径相差较大,且软晶格导致卤素离子迁移,会导致CsPbI_(3)量子点发生相变,即失效。利用铅基金属有机框架(Pb metal organic framework,Pb-MOF)作为钙钛矿中的铅源,合成CsPbI_(3)量子点(CsPbI_(3)@Pb-MOF-OLAMI)。结果表明,其热稳定性提升了40%,而光照稳定性在经过碘化铅(PbI_(2))离子源溶液的修复后,提升了15倍。这种稳定性的改善主要源于孔洞限制效应,即Pb-MOF的多孔结构阻碍或减缓卤素离子的迁移,避免或减少缺陷的形成,也就抑制了钙钛矿变性过程。该研究为改善钙钛矿量子点CsPbI_(3)的稳定性提供了新思路。
