Nano-moiré method presented in this paper is an experimental technique which allows direct measurement of nanoscopic mechanical parameters, such as displacement, strain and dislocation distribution. The basic ide...Nano-moiré method presented in this paper is an experimental technique which allows direct measurement of nanoscopic mechanical parameters, such as displacement, strain and dislocation distribution. The basic idea is the formation of moiré fringes when a HREM (high resolution electron microscopy) image of crystal material is superimposed with a unidirectional grating. Fourier filtering technique is used to increase the contrast of fringes and to multiple the fringes. This method has atom-size sensitivity and spatial resolution, and relatively large range. It provides a new experimental technique with very high sensitivity and spatial resolution for nanomechanics.展开更多
Artificial biomaterials with dynamic mechano-responsive behaviors similar to those of biological tissues have been drawing great attention.In this study,we report a TiO_(2)-based nanowire(TiO_(2)NWs)scaffolds,which ex...Artificial biomaterials with dynamic mechano-responsive behaviors similar to those of biological tissues have been drawing great attention.In this study,we report a TiO_(2)-based nanowire(TiO_(2)NWs)scaffolds,which exhibit dynamic mechano-responsive behaviors varying with the number and amplitude of nano-deformation cycles.It is found that the elastic and adhesive forces in the TiO_(2)NWs scaffolds can increase significantly after multiple cycles of nano-deformation.Further nanofriction experiments show the triboelectric effect of increasing elastic and adhesive forces during the nano-deformation cycles of TiO_(2)NWs scaffolds.These properties allow the TiO_(2)NW scaffolds to be designed and applied as intelligent artificial biomaterials to simulate biological tissues in the future.展开更多
There is a more consanguineous relation be-tween nano-scale deformation of coal structure and meta-morphic-deformed environment. In different metamor-phic-deformed environments, deformation in the coal struc-ture can ...There is a more consanguineous relation be-tween nano-scale deformation of coal structure and meta-morphic-deformed environment. In different metamor-phic-deformed environments, deformation in the coal struc-ture can occur not only at micro-scale, but also at nano-scale, and even leads to the change of molecular structure and nano-scale pore (<100 nm) structure. The latter is the main space absorbing coalbed methane. Through X-ray diffraction (XRD) and liquid–nitrogen absorption methods, the charac-teristics of macromolecular and nano-scale pore structures of coals in different metamorphic-deformed environments and deformational series of coals have been studied. By combin-ing with high-resolution transmission electron microcopy (HRTEM), the macromolecular and nano-scale pore struc-tures are also directly observed. These results demonstrate that the stacking Lc of the macromolecular BSU in tectonic coals increases quickly from the metamorphic-deformed environment of low rank coals to that of high rank coals. For different deformed tectonic coals, in the same metamor-phic-deformed environment, the difference of Lc is obvious. These changes reflect chiefly the difference of different tem-perature and stress effect of nano-scale deformation in tec-tonic coals. The factor of temperature plays a greater role in the increase of macromolecular structure parameters Lc, the influence of stress factor is also important. With the stress strengthening, Lc shows an increasing trend, and La /Lc shows a decreasing trend. Therefore, Lc and La /Lc can be used as the indicator of nano-scale deformation degree of tectonic coals. With increasing temperature and pressure, especially oriented stress, the orientation of molecular structure be-comes stronger, and ordering degree of C-nets and the ar-rangement of BSU are obviously enhanced. For the deforma-tion of nano-scale pore structure, in the same metamor-phic-deformed environment, along with the strengthening of stress, the ratio of mesopores to its total pores volume of tec-toni展开更多
The deformation behavior and formability of gradient nano-grained（GNG） AISI 304 stainless steel in uniaxial and biaxial states were investigated by means of tensile test and small punch test（SPT）. The GNG top laye...The deformation behavior and formability of gradient nano-grained（GNG） AISI 304 stainless steel in uniaxial and biaxial states were investigated by means of tensile test and small punch test（SPT）. The GNG top layer was fabricated on coarse grains（CG） AISI 304 by ultrasonic impact treatment. The results showed that the CG substrate could effectively suppress the strain localization of NC in GNG layer, and an approximate linear relationship existed between the thickness of substrate（h） and uniform true strain before necking（ε_（unif））. Grain growth of NC was observed at the stress state with high Stress triaxiality T, which led to better ductility of GNG/CG 304 in SPT, as well as similar true strain after the onset of necking（ε_（neck）） compared with coarse 304 in tensile test. Ei-values of GNG/CG 304 with different structures were nearly the same at different punch speeds, and good formability of GNG/CG 304 was demonstrated. However, punch speed and microstructure needed to be optimized to avoid much lost of membrane strain region in biaxial stress state.展开更多
聚焦离子束技术(focused ion beam,FIB)由于其高精度刻蚀、定点加工、实时成像等优势,常用于精密加工、TEM制样等领域。其工作机理通常为:刻蚀、淀积与成像。而基于FIB新的加工手段正在被探索和研究,其中就包括两种聚焦离子束致形变技术...聚焦离子束技术(focused ion beam,FIB)由于其高精度刻蚀、定点加工、实时成像等优势,常用于精密加工、TEM制样等领域。其工作机理通常为:刻蚀、淀积与成像。而基于FIB新的加工手段正在被探索和研究,其中就包括两种聚焦离子束致形变技术,分别为聚焦离子束应力引入致形变技术(FIB-stress induced deformation,FIBSID)和聚焦离子束物质再分布致形变技术(FIB-material-redistribution induced deformation,FIB-MRD)。前者通过控制FIB辐照时离子注入与溅射之间的竞争关系实现悬臂梁的多角度弯曲,后者利用粒子与物质作用时的瑞利不稳定性构建纳米结构,在一定意义上扩充了聚焦离子束的应用范围。运用上述方法可以加工三维微纳螺旋,悬浮光滑纳米弦以及大规模阵列化纳米网孔等多样化微/纳功能构件,在微流控系统,太赫兹通信,光学天线等领域具有很强的应用前景。展开更多
基金The project supported by the National Natural Science Foundation of China
文摘Nano-moiré method presented in this paper is an experimental technique which allows direct measurement of nanoscopic mechanical parameters, such as displacement, strain and dislocation distribution. The basic idea is the formation of moiré fringes when a HREM (high resolution electron microscopy) image of crystal material is superimposed with a unidirectional grating. Fourier filtering technique is used to increase the contrast of fringes and to multiple the fringes. This method has atom-size sensitivity and spatial resolution, and relatively large range. It provides a new experimental technique with very high sensitivity and spatial resolution for nanomechanics.
基金supported by the National Natural Science Foundation of China(No.52205198)the Ningbo Natural Science Foundation(No.202003N4091)Ministry of Education of Key Laboratory of Impact and Safety Engineering at Ningbo University(No.CJ202108).
文摘Artificial biomaterials with dynamic mechano-responsive behaviors similar to those of biological tissues have been drawing great attention.In this study,we report a TiO_(2)-based nanowire(TiO_(2)NWs)scaffolds,which exhibit dynamic mechano-responsive behaviors varying with the number and amplitude of nano-deformation cycles.It is found that the elastic and adhesive forces in the TiO_(2)NWs scaffolds can increase significantly after multiple cycles of nano-deformation.Further nanofriction experiments show the triboelectric effect of increasing elastic and adhesive forces during the nano-deformation cycles of TiO_(2)NWs scaffolds.These properties allow the TiO_(2)NW scaffolds to be designed and applied as intelligent artificial biomaterials to simulate biological tissues in the future.
基金This work was supported by the National Key Development Plan Project of Basic Research(973 Plan)(Grant No.2002CB211704)the National N atural Science Foundation of China(Grant No.40172058)+1 种基金China Postdoctoral Science Foundation(Grant No.200403508)Kuancheng Wang Post-doctoral Research Award Fund of Chinese Academy of Sciences.
文摘There is a more consanguineous relation be-tween nano-scale deformation of coal structure and meta-morphic-deformed environment. In different metamor-phic-deformed environments, deformation in the coal struc-ture can occur not only at micro-scale, but also at nano-scale, and even leads to the change of molecular structure and nano-scale pore (<100 nm) structure. The latter is the main space absorbing coalbed methane. Through X-ray diffraction (XRD) and liquid–nitrogen absorption methods, the charac-teristics of macromolecular and nano-scale pore structures of coals in different metamorphic-deformed environments and deformational series of coals have been studied. By combin-ing with high-resolution transmission electron microcopy (HRTEM), the macromolecular and nano-scale pore struc-tures are also directly observed. These results demonstrate that the stacking Lc of the macromolecular BSU in tectonic coals increases quickly from the metamorphic-deformed environment of low rank coals to that of high rank coals. For different deformed tectonic coals, in the same metamor-phic-deformed environment, the difference of Lc is obvious. These changes reflect chiefly the difference of different tem-perature and stress effect of nano-scale deformation in tec-tonic coals. The factor of temperature plays a greater role in the increase of macromolecular structure parameters Lc, the influence of stress factor is also important. With the stress strengthening, Lc shows an increasing trend, and La /Lc shows a decreasing trend. Therefore, Lc and La /Lc can be used as the indicator of nano-scale deformation degree of tectonic coals. With increasing temperature and pressure, especially oriented stress, the orientation of molecular structure be-comes stronger, and ordering degree of C-nets and the ar-rangement of BSU are obviously enhanced. For the deforma-tion of nano-scale pore structure, in the same metamor-phic-deformed environment, along with the strengthening of stress, the ratio of mesopores to its total pores volume of tec-toni
基金Funded by the National National Natural Science Foundation of China(No.51505189)Open Project of Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment&Technology(No.FM-2015-5)
文摘The deformation behavior and formability of gradient nano-grained（GNG） AISI 304 stainless steel in uniaxial and biaxial states were investigated by means of tensile test and small punch test（SPT）. The GNG top layer was fabricated on coarse grains（CG） AISI 304 by ultrasonic impact treatment. The results showed that the CG substrate could effectively suppress the strain localization of NC in GNG layer, and an approximate linear relationship existed between the thickness of substrate（h） and uniform true strain before necking（ε_（unif））. Grain growth of NC was observed at the stress state with high Stress triaxiality T, which led to better ductility of GNG/CG 304 in SPT, as well as similar true strain after the onset of necking（ε_（neck）） compared with coarse 304 in tensile test. Ei-values of GNG/CG 304 with different structures were nearly the same at different punch speeds, and good formability of GNG/CG 304 was demonstrated. However, punch speed and microstructure needed to be optimized to avoid much lost of membrane strain region in biaxial stress state.
