The adsorption and electronic properties of isolated cobalt phthalocyanine (CoPc) molecule on an ultrathin layer of NaC1 have been investigated. High-resolution STM images give a detailed picture of the lowest unocc...The adsorption and electronic properties of isolated cobalt phthalocyanine (CoPc) molecule on an ultrathin layer of NaC1 have been investigated. High-resolution STM images give a detailed picture of the lowest unoccupied molecular orbital (LUMO) of an isolated CoPc. It is shown that the NaC1 ultrathin layer efficiently decouples the interaction of the molecules from the underneath metal substrate, which makes it an ideal substrate for studying the properties of single molecules. Moreover, strong dependence of the appearance of the molecules on the sample bias in the region of relatively high bias (〉 3.1 V) is ascribed to the image potential states (IPSs) of NaCI/Cu(100), which may provide us with a possible method to fabricate quantum storage devices.展开更多
The problem of the elastic interaction between a screw dislocation and a three-phase circular inclusion with interracial rigid lines (anti-cracks) is investigated. An efficient and concise method for the complex mul...The problem of the elastic interaction between a screw dislocation and a three-phase circular inclusion with interracial rigid lines (anti-cracks) is investigated. An efficient and concise method for the complex multiply connected region is developed, with which explicit series form solutions of the complex potentials in the matrix, and the interphase layer and inclusion regions are derived. Based on the complex potentials, the image force on the screw dislocation is then calculated by using the Peach-Koehler formula. The equilibrium position of the dislocation is discussed in detail for various rigid line geometries, interphase layer thicknesses and material property combinations. The main results show that the interracial rigid lines exert a significant perturbation effect on the motion of the screw dislocation near the circular inclusion surrounded by an interphase layer.展开更多
A convenient fabrication technique for samarium hexaboride(SmB6) nanostructures(nanowires and nanopencils) is developed, combining magnetron-sputtering and chemical vapor deposition. Both nanostructures are proven...A convenient fabrication technique for samarium hexaboride(SmB6) nanostructures(nanowires and nanopencils) is developed, combining magnetron-sputtering and chemical vapor deposition. Both nanostructures are proven to be single crystals with cubic structure, and they both grow along the [001] direction. Formation of both nanostructures is attributed to the vapor-liquid-solid(VLS) mechanism, and the content of boron vapor is proposed to be the reason for their different morphologies at various evaporation distances. Field emission(FE) measurements show that the maximum current density of both the as-grown nanowires and nanopencils can be several hundred μA/cm^2, and their FN plots deviate only slightly from a straight line. Moreover, we prefer the generalized Schottky-Nordheim(SN) model to comprehend the difference in FE properties between the nanowires and nanopencils. The results reveal that the nonlinearity of FN plots is attributable to the effect of image potential on the FE process, which is almost independent of the morphology of the nanostructures.All the research results suggest that the SmB6 nanostructures would have a more promising future in the FE area if their surface oxide layer was eliminated in advance.展开更多
A new multivariate statistical strategy for analyzing large datasets that are produced by imaging mass spectrometry(IMS) techniques is reported.The strategy divides the whole datacube of the sample into several subs...A new multivariate statistical strategy for analyzing large datasets that are produced by imaging mass spectrometry(IMS) techniques is reported.The strategy divides the whole datacube of the sample into several subsets and analyses them one by one to obtain the results.Instead of analyzing the whole datacube at one time,the strategy makes the analysis easier and decreases the computation time greatly.In this report,the IMS data are produced by the air flow-assisted ionization IMS(AFAI-IMS).The strategy can be used in combination with most multivariate statistical analysis methods.In this paper,the strategy was combined with the principal component analysis(PCA) and partial least square analysis(PLS).It was proven to be effective by analyzing the handwriting sample.By using the strategy,the m/z corresponding to the specific lipids in rat brain tissue were distinguished successfully.Moreover the analysis time grew linearly instead of exponentially as the size of sample increased.The strategy developed in this study has enormous potential for searching for the mjz of potential biomarkers quickly and effectively.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.21203239 and 21311120059)RFBR(Grant No.13-02-91180)
文摘The adsorption and electronic properties of isolated cobalt phthalocyanine (CoPc) molecule on an ultrathin layer of NaC1 have been investigated. High-resolution STM images give a detailed picture of the lowest unoccupied molecular orbital (LUMO) of an isolated CoPc. It is shown that the NaC1 ultrathin layer efficiently decouples the interaction of the molecules from the underneath metal substrate, which makes it an ideal substrate for studying the properties of single molecules. Moreover, strong dependence of the appearance of the molecules on the sample bias in the region of relatively high bias (〉 3.1 V) is ascribed to the image potential states (IPSs) of NaCI/Cu(100), which may provide us with a possible method to fabricate quantum storage devices.
基金Project supported by the National Natural Science Foundation of China (No.10472030).
文摘The problem of the elastic interaction between a screw dislocation and a three-phase circular inclusion with interracial rigid lines (anti-cracks) is investigated. An efficient and concise method for the complex multiply connected region is developed, with which explicit series form solutions of the complex potentials in the matrix, and the interphase layer and inclusion regions are derived. Based on the complex potentials, the image force on the screw dislocation is then calculated by using the Peach-Koehler formula. The equilibrium position of the dislocation is discussed in detail for various rigid line geometries, interphase layer thicknesses and material property combinations. The main results show that the interracial rigid lines exert a significant perturbation effect on the motion of the screw dislocation near the circular inclusion surrounded by an interphase layer.
基金Project supported by the National Key Basic Research Program of China(Grant No.2013CB933601)National Project for the Development of Key Scientific Apparatus of China(Grant No.2013YQ12034506)+3 种基金the Fundamental Research Funds for the Central Universities of Chinathe Science and Technology Department of Guangdong Province,Chinathe Education Department of Guangdong Province,Chinathe Natural Science Foundation of Guangdong Province,China(Grant No.2016A030313313)
文摘A convenient fabrication technique for samarium hexaboride(SmB6) nanostructures(nanowires and nanopencils) is developed, combining magnetron-sputtering and chemical vapor deposition. Both nanostructures are proven to be single crystals with cubic structure, and they both grow along the [001] direction. Formation of both nanostructures is attributed to the vapor-liquid-solid(VLS) mechanism, and the content of boron vapor is proposed to be the reason for their different morphologies at various evaporation distances. Field emission(FE) measurements show that the maximum current density of both the as-grown nanowires and nanopencils can be several hundred μA/cm^2, and their FN plots deviate only slightly from a straight line. Moreover, we prefer the generalized Schottky-Nordheim(SN) model to comprehend the difference in FE properties between the nanowires and nanopencils. The results reveal that the nonlinearity of FN plots is attributable to the effect of image potential on the FE process, which is almost independent of the morphology of the nanostructures.All the research results suggest that the SmB6 nanostructures would have a more promising future in the FE area if their surface oxide layer was eliminated in advance.
基金supported by the National Instrumentation Programmme(Nos.2011YQ17006702 and 2011YQ14015010)the National Natural Science Foundation of China(Nos.81102413 and 21175121)Fundamental Research Program of Shenzhen (No.JC201005280634A).
文摘A new multivariate statistical strategy for analyzing large datasets that are produced by imaging mass spectrometry(IMS) techniques is reported.The strategy divides the whole datacube of the sample into several subsets and analyses them one by one to obtain the results.Instead of analyzing the whole datacube at one time,the strategy makes the analysis easier and decreases the computation time greatly.In this report,the IMS data are produced by the air flow-assisted ionization IMS(AFAI-IMS).The strategy can be used in combination with most multivariate statistical analysis methods.In this paper,the strategy was combined with the principal component analysis(PCA) and partial least square analysis(PLS).It was proven to be effective by analyzing the handwriting sample.By using the strategy,the m/z corresponding to the specific lipids in rat brain tissue were distinguished successfully.Moreover the analysis time grew linearly instead of exponentially as the size of sample increased.The strategy developed in this study has enormous potential for searching for the mjz of potential biomarkers quickly and effectively.