Effects of substrate hydrophobicity/hydrophilicity on height measurement of individual ds-DNA molecules are investigated with tapping mode atomic force microscopy （TMAFM） and vibrating mode scanning polarization for...Effects of substrate hydrophobicity/hydrophilicity on height measurement of individual ds-DNA molecules are investigated with tapping mode atomic force microscopy （TMAFM） and vibrating mode scanning polarization force microscopy （VSPFM）. The measured heights of ds-DNA on hydrophobic highly oriented pyrolytic graphite （HOPG） are remarkably less than those on hydrophilic bare mica and Ni^2＋ treated mica in both TMAFM and VSPFM. By analysing the results, we propose that the hydrophobicity/hydrophilicity of substrate can greatly influence the height measurement of DNA molecules.展开更多
To understand capillary interactions between probe tips and nanoparticles under ambient conditions, a theoretical model of capillary forces between them is developed based on the geometric relations. It is found that ...To understand capillary interactions between probe tips and nanoparticles under ambient conditions, a theoretical model of capillary forces between them is developed based on the geometric relations. It is found that the contribution of surface tension force to the total capillary force attains to similar order of magnitude as the capillary pressure force in many cases. It is also shown that the tip shape and the radial distance of the meniscus have great influence on the capillary force. The capillary force decreases with the increasing separation distances, and the variance of the contact angles may change the magnitudes of capillary forces several times at large radial distances. The applicability of the symmetric meniscus approximation is discussed.展开更多
Regimes of continuous and pulsed laser action on high-melting oxide compounds of ZrO2 were found with the aim of obtaining steady coatings on monocrystal silicon on laser ablation.X-ray phase analyses,scanning and ato...Regimes of continuous and pulsed laser action on high-melting oxide compounds of ZrO2 were found with the aim of obtaining steady coatings on monocrystal silicon on laser ablation.X-ray phase analyses,scanning and atomic-force microscopy reveal that the coatings obtained are of nanocluster structure with the cubic ordering.In this case the nanoclusters reach several hundreds of nanometers in size.An assumption was made that on laser ablation of ZrO2 thermostabilization may take place where a minimum of the surface energy is attained just at cubic ordering.展开更多
The role of substrate roughness in ZnO nanowire（NW） arrays hydrothermal growth has been systematically studied.Six silicon substrates with different roughness by chemical etching have been selected to grow ZnO NW ar...The role of substrate roughness in ZnO nanowire（NW） arrays hydrothermal growth has been systematically studied.Six silicon substrates with different roughness by chemical etching have been selected to grow ZnO NW arrays hydrothermally after sputtering 5-nm-thick ZnO seed layer as catalyst.The as-grown samples reveal that average diameters and number densities of ZnO NW arrays are inversely proportional to the increasing substrate roughness observed by atomic-force microscopy and scanning electron microscopy.Furthermore,the theoretically derived equations based on nucleation with the Gibbs free energy to describe relations of substrate roughness versus average NW diameter and NW number density match well with experimental results.Research results in this paper can be used to control the number density and the average diameter of ZnO NW arrays by alternating substrate roughness.展开更多
Scanning probe microscopy(SPM) stands out as one of the most powerful tools for characterizing the solid surface and the adsorbed molecules with ?ngstr?m resolution in real space. In particular, this unique technique ...Scanning probe microscopy(SPM) stands out as one of the most powerful tools for characterizing the solid surface and the adsorbed molecules with ?ngstr?m resolution in real space. In particular, this unique technique provides an unprecedented opportunity for directly probing the low-dimensional ices at surfaces. In this perspective, we first review the recent advances of scanning tunneling microscopy(STM) imaging of various two-dimensional(2 D) ice structures on metal[1-7], insulator[8-12], graphite[13-15] surfaces and under strong confinement[10, 16-19]. We then introduce that noncontact atomic-force microscopy(AFM) with a CO-terminated tip enables atomic imaging of a genuine 2 D ice grown on a hydrophobic Au(111) surface with minimal perturbation[20], paying particular attention to the growth processes at the edges of 2 D ice. In the end, we present an outlook on the future applications of 2 D ice as well as the relation between the 2 D and 3 D ice growth.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10335070, 10404032, 30470441, 90406024-6, 60575029, 10304011 and 10604034, the Chinese Academy of Sciences under Grant No Y2005029, the Science and Technology Com- mission of Shanghai Municipality under Grant Nos 04qmx1466, 0552nm033 and 0552nm027, the Ningbo Municipal Natural Science Foundation of China under Grant No 2006A610046, and the New Energy and Industrial Technology Development 0rganization under Grant No 051IS128.
文摘Effects of substrate hydrophobicity/hydrophilicity on height measurement of individual ds-DNA molecules are investigated with tapping mode atomic force microscopy （TMAFM） and vibrating mode scanning polarization force microscopy （VSPFM）. The measured heights of ds-DNA on hydrophobic highly oriented pyrolytic graphite （HOPG） are remarkably less than those on hydrophilic bare mica and Ni^2＋ treated mica in both TMAFM and VSPFM. By analysing the results, we propose that the hydrophobicity/hydrophilicity of substrate can greatly influence the height measurement of DNA molecules.
文摘To understand capillary interactions between probe tips and nanoparticles under ambient conditions, a theoretical model of capillary forces between them is developed based on the geometric relations. It is found that the contribution of surface tension force to the total capillary force attains to similar order of magnitude as the capillary pressure force in many cases. It is also shown that the tip shape and the radial distance of the meniscus have great influence on the capillary force. The capillary force decreases with the increasing separation distances, and the variance of the contact angles may change the magnitudes of capillary forces several times at large radial distances. The applicability of the symmetric meniscus approximation is discussed.
基金This work is financially supported by the Russian Foundation for Basic Research (No 04-02-9700and 06-02-9600)by the Presidium of the Far Eastern Branch of the Russian Academy of Sciences(No 06-III-A-02-034)
文摘Regimes of continuous and pulsed laser action on high-melting oxide compounds of ZrO2 were found with the aim of obtaining steady coatings on monocrystal silicon on laser ablation.X-ray phase analyses,scanning and atomic-force microscopy reveal that the coatings obtained are of nanocluster structure with the cubic ordering.In this case the nanoclusters reach several hundreds of nanometers in size.An assumption was made that on laser ablation of ZrO2 thermostabilization may take place where a minimum of the surface energy is attained just at cubic ordering.
基金supported by Jiangsu Provincial Department of Education with the 2012 Project of Overseas Research of Distinguished Young and Middle-aged Teachers and Principalsthe University of Alabama startup fund
文摘The role of substrate roughness in ZnO nanowire（NW） arrays hydrothermal growth has been systematically studied.Six silicon substrates with different roughness by chemical etching have been selected to grow ZnO NW arrays hydrothermally after sputtering 5-nm-thick ZnO seed layer as catalyst.The as-grown samples reveal that average diameters and number densities of ZnO NW arrays are inversely proportional to the increasing substrate roughness observed by atomic-force microscopy and scanning electron microscopy.Furthermore,the theoretically derived equations based on nucleation with the Gibbs free energy to describe relations of substrate roughness versus average NW diameter and NW number density match well with experimental results.Research results in this paper can be used to control the number density and the average diameter of ZnO NW arrays by alternating substrate roughness.
文摘Scanning probe microscopy(SPM) stands out as one of the most powerful tools for characterizing the solid surface and the adsorbed molecules with ?ngstr?m resolution in real space. In particular, this unique technique provides an unprecedented opportunity for directly probing the low-dimensional ices at surfaces. In this perspective, we first review the recent advances of scanning tunneling microscopy(STM) imaging of various two-dimensional(2 D) ice structures on metal[1-7], insulator[8-12], graphite[13-15] surfaces and under strong confinement[10, 16-19]. We then introduce that noncontact atomic-force microscopy(AFM) with a CO-terminated tip enables atomic imaging of a genuine 2 D ice grown on a hydrophobic Au(111) surface with minimal perturbation[20], paying particular attention to the growth processes at the edges of 2 D ice. In the end, we present an outlook on the future applications of 2 D ice as well as the relation between the 2 D and 3 D ice growth.
