FABRICATION OF THE TIP FOR ELECTROCHEMICAL SCANNING TUNNELING MICROSCOPY

A nover technique for the fabrication of the tip for e tectrochemical scanning tunneting microscopy(ECSTM)is presented. The curvature radius of the fabricated tip is smatter than 1 μM. Faradaic leakage current is tess than 0.1nA in the sotution of 1 mol/L NaCl. The atomic image of highty oriented pyrotytic graphite (HOPG)has been taken using the prepared tip.

Dependence of Morphology of SiO_(x) Nanowires on the Supersaturation of Au-Si Alloy Liquid Droplets Formed on the Au-Coated Si Substrate

A thermodynamic theory about the dependence of morphology of SiOx nanowires on the super-saturation of alloy liquid droplets has been proposed on the basis of the vapour-liquid-solid growth mechanism and has been supported experimentally. By changing the Si concentration in the Au-Si liquid droplets formed on the Au-coated Si substrate, firework-, tulip- and bud-shaped SiOx nanowires were synthesized by a thermal evaporation method and distributed concentrically around some void defects in the Si substrate. Voids were formed underneath the surface of the Si substrate during the thermal evaporation at 850℃ and resulted in the Si-concentration deficient thus different saturation of Au-Si droplets. Electron microscopy analysis showed that the nanowires had an amorphous structure and were terminated by Au-Si particles.

Measurement of the remnant magnetic-field in Lorentz mode using permalloy

A novel method was reported to measure the remnant magnetic field in Lorentz mode in a FEI Tecnai F20 transmission electron microscope equipped with a Lorentz lens. The movement of the circle Bloch line of the cross-tie wall in Permalloy is used to measure the remnant magnetic field by tilting the specimen and adjusting the objective lens current. The remnant magnetic field is estimated to be about 17 Oe, in a direction opposite to that of the objective lens magnetic field. The remnant magnetic field can be compensated by adjusting the value of the objective lens current.

Stable Mg- Zn-Y Quasicrystals

By conventional air-cooled casting method,cast ingots with large contents of stable Mg-Zn-Y quasicrystals were obtained.It was shown that most of the quasicrystals are of face-centered icosahedral type,while a few of them belong to simple icosahedral type.The quasicrystals were stable during the continuous heating with the temperature below 868K.The oxidizing reactions were observed at high temperature.This is the characteristic of Mg-Zn-Y alloys,which differs from that of A1 base alloys.

AN ELECTRON MICROSCOPE STUDY OF MINERAL GROUP OF FRANCKEITE

Franckeite and cylindrite of franckite mineral group were examined in the transmission electron microscope. Selected-area electron diffraction indicated that in the structure exists a long period, belonging to an incommensurate modulation period. The incommensurate modulation in this kind of minerals results from sine undular structure sheets. The excellent correspondence between high resolution simulated computer image and observed image was obtained on the basis of the structure of franckeite and cylindrite which was put forward in this paper. First, the fact that in the structures of franckeite and cylindrite exist two kinds of structure sheets whose lattices are different has been proved by experiment, i. e. false tetragonal symmetrical galena structure sheets(t sheets)and false hexagonal SnS_2 sheets(h sheets). The two kinds of sheets are packed in order of htht…

Observation of Radiation Damage of Energetic Heavy Ions Impacts on MoS Surface by Scanning Tunneling Microscopy

Natural MoS_2 surface bombarded by Au ions with 13.4 MeV/nucleon was investigated using scanning tunneling microscope (STM) in ambient air. Rather high ion doses 1×10^(13) cm^(-2) were used in order to have more chances to get damaged images. Not only atomic structures of the original surface, but also arrangements on the elevated regions even at the bottom of the craters are clearly shown in the STM images. In general, there is a one-to-one correlation between the number of ion impacts and the number of craters.

Three-dimensional structure of the wild-type RHDV

The three-dimensional (3D) structure of the wild-type rabbit hemorrhagic disease virus (RHDV) has been determined to a resolution of 3.2 nm by electron cryo-microscopy and computer image reconstruction techniques. The 3D density map exhibits characteristic structural features of a calicivirus: a T=3 icosahedral capsid with 90 arch-like capsomeres at the icosahedral and local 2-fold axes and 32 large surface hollows at the icosahedral 5- and 3-fold axes. This result confirms that the RHDV isolated in China is a member of the Caliciviridae family. A rather continuous capsid shell was found without channels. However, our RHDV structure also reveals some distinct structural char-acteristics not observed in other caliciviruses, including interconnected capsomeres and the lack of protuberance on the base of each of the surface hollows. Two types of particles were identified with similar outer capsid structure but different density distributions inside the capsid shells, which could not be distinguished by