There still exist numerous problems to be solved in steel manufacturing processes or steel products, which are somehow related to surface or interface properties. Progress in experimental techniques in the field of surface or interface analysis is firstly described from a historical viewpoint. Then, emphasis is placed upon the intoroduction of recent experimental attainments in clarifying the relationship between surface or interface chemistry and propreties of steel products. Future problems to be solved are also discussed.
An experimental investigation was made of the formation of thermal pits and hillocks produced on (111) and (100) surfaces of silicon by heating in the temperature range 800°C-1, 300°C in a high vacuum at 3×10-7 Torr and 3×10-8 Torr. It was found that the formation of the thermal pits are caused by preferential thermal etching of surfaces contaminated with initial adsorbates and adsorption of residual gases. Contamination by initial adsorbates was found to form the oriented thermal pits. Residual gases at 3×10-7 Torr were found to form hillocks due to reaction with Si. The presence of β-SiC was always observed on RHEED patterns obtained from surfaces having the thermal pits and hillocks. The effect of thin oxide films on silicon were also investigated. No thermal pits were observed on the surfaces heated with oxide films, even at 3×10-7 Torr.
In high resolution observation of ultra-fine uneven surfaces of specimens, the image of replica films obtained by the normal single-stage replica method on specimen surfaces with uneven structure, less than 10nm in size, is deformed by the evaporated materials, even though the thickness of the evaporated film is only a few nm. Therefore, the smallest size of a replicated square-shaped object, that can be recognized as square shaped one, is about 5×5nm2. In the new method, the unevenness of specimen surfaces is covered with evaporated film by conventional vacuum evaporation. As a result, fine details of surface structures are correctly removed with little deformation and are clearly observed in the replica image. The smallest square shaped object, of 1.12×1.12nm2 size, that appeared in the replica image, is twice as large as the unit cell of NaCl crystal.
Effects of angular factors on film formation in a sputter-deposition system were studied. Two kinds of angles relating to the geometry of the sputter system were taken as the anglar factors. On is the radiation angle θ of particles sputtered from a target, and the other the incident angle, δ, at which the particles enter the surface. For this purpose, twenty Si (100) substrates were set in a vacuum system in the corresponding angular conditions. Ag or SiO2 films were simultaneously deposited on their surfaces using the Xe+ (0.5KeV or 1.5KeV) ion beam sputter-deposition method. Morphology and thickness of the films were examined by SEM and EPMA. Strong dependence was found of θ and δ on the morphology and the deposition rate of the film. These results are discussed from two points of view : (1) the angular dependence of the energy distribution on the sputtered particles, and (2) the angular and energy dependence of the sticking probability of the particles onto the substrate. The latter is explained with the energy selective deposition mechanism of the substrates inclined by δ.
Nerve excitation has been considered as the voltage- and time- dependent opening and closure of the Na and K channels. This can well explain macroscopic electro-physiological measurements results. Recent biochemical studies of Na and K channels show that the complete purification of their proteins and their incorporation into the artificial lipid bilayer membrane to form the active voltage-dependent ionic channels, will be accomplished in the near future. On the other hand, biophysical and physiological studies using intact nerve fibres have elucidated properties of single channels in the nerve membrane. Now we must increase effort to explain the nerve excitation, which is the macroscopic phenomenon, by distinguishing the microscopic nature of the single channel from the macroscopic nature of many channels activated during the nerve excitation.
Experimental research of the two-dimensional electron system bound on a liquid helium surface is reviewed. Introductory description is given of the image-potential-induced electronic surface state and of the two-dimensional electron system. Discussion is mainly focused upon the electron correlation effect and the liquid-solid phase transition of the electron system. The experiment by Grimes and Adams, which presented the first experimental evidence for Wigner crystallization of the surface electron system, is explained in detail. Other related experiments are described.