Conductance behaviours of resonant tunneling junction with elementary, second and third Sier pinskii structures are considered. Numerical calculation shows that a tunneling junction with higher order fractal structure possesses more meticulous resonant behaviour. It provides the possibility of fabricating exact energy selecting tunneling devices. The structure of tunneling junction can be determined by experimental observation. The energetic spectrum of such device is supposed to be a fractal one. The effect of electrode is alteration of the shape and maximum of conductance peaks.

CdS nanoparticles were prepared in air and their stability by air annealing was studied. A small change in crystal structure and particle size was observed by air annealing, but a rapid reduction in fluorescence was found. Through investigation, it is revealed that it is the surface change or reconstruction rather than the variation of the size or structure that decreases the fluorescence.The emission of the particles consists with two peaks which are dependent on the excitation energy. The two peaks are considered to be arisen from "two" different sizes of nanoparticles and may be explained in terms of selectively excited photoluminescence. Finally we discuss why the discrete state of nanoparticles are able to be resolved in the photoluminescence excitation spectrum, but could not be differentiated in the absorption spectrum.

New spiral nano-fibers were synthesized by a polymerization process of acetylene with metal nanoparticles as catalysts which were prepared by a hydrogen arc plasma method. The microstructures, conductive property of the nano-fibers and the effects of different nanoparticles(catalysts) on the microstructures of the fibers were studied.

Work-hardening behaviour of type 316 austenitic stainless steel having difFerent initial dislocation structures introduced by swaging to various levels is analysed by a simplified Kock's model which takes into account the structural changes through the dislocation accumulation and annihilation process during deformation. The dislocation accumulation and annihilation factors show a temperature and structure dependence. The dislocation annihilation factor shows a plateau or decreasing tendency in the dynamic strain ageing (DSA) temperature range. This is attributed as either due to dislocation accumulation being more pronounced than dislocation annihilation or as due to precipitates being formed at DSA temperatures acting as obstacles to dislocation motion in the DSA temperature range.

In this paper, a rapidly solidified Al-Si-Fe-Cu-Mg alloy was prepared by spray deposition. The microstructure of the alloy includes silicon phase and δ-(Al,Fe,Si). Al8Si6Mg3Fe, FeAl2 and small FeSi2 phases. The reasons of the formation of silicon and δ-(Al,Fe,Si) phase were analyzed. The tensile properties at the temperatures of room to 350℃ were investigated, and the strengthening mechanism was suggested. The wear resistance and cutability of the alloy were measured as well.

Microstructure of rapidly solidified Al-3.8Li-0.8Mg-0.4Cu-0.13Zr alloy prepared by spray deposition has been investigated. The grains are 5~ 20μm in size, and the microstructure exhibits the rapid solidification merits. Shrinkage porosities have been avoided, and the formation of prior particle boundary (PPB) has been prevented to a large extent. But there still exist some micropores with various shapes. The relative density of the as-deposited material is 94% on average.The main precipitates in the tested alloy are δ(AlLi), S(Al2CuMg) and δ'(Al3Li) phases.

Ti-35V15Cr-0.05C is a new nonburning titanium alloy. The structural analyses show that the alloy consists of β phase and lath-like α phase distributed within β grains, and some titanium carbide particles appear at grain boundaries. Using dark field TEM method, it was also found that TiCr2 phase uniformly precipitates in α phase. After heat treatment at 900℃ for 15 min,equiaxed β phase of 60~ 80μm in diameter and lath-like α phase of 1-2% volume fraction were observed. This alloy possesses attractive mechanical properties.

The microcracking behaviour of TiAl-based alloys with the duplex and fully-lamellar microstrcutures was studied during compression. It was found that the fracture involves propagation of the existing microcracks and development of more new nuclei, instead of being a nucleationcontrolled event. The lamellar interfaces, especially those having an angle of about 0~30℃ to the loading axis, were found to be the favourable nucleation sites. Microcrack nucleation is likely to be initiated by tensile normal stress concentrated on the lamellar interfaces.

Single-stage and double-stage interrupted hot compression tests for simulating hot rolling have been carried out for a Ti-containing HSLA steel (10Ti). Physical simulation of hot rolling was in progress utilizing a Thermecmastor-Z simulator in 850~1150℃ and strain rate of 0.1~60 s-1.A model for residual strain ratio λ was designed, and a model of flow stress considering residual strain has been obtained. The hot deformation behaviour at various strain rates has been studied.

Zirconia membrane was prepared in the sol-gel process by filtering viscous colloidal zirconia sol through microporous alumina support and gelling followed by sintering at 743 K. The scanning electron micrograph show that mean pore size was 543 nm and pore density was 1.47×107/cm2.The filtration characteristics during membrane layer formation showed that the membrane layer formation started after 40 min. The membrane layer thickness and the porosity of the membrane were determined gravimetrically by finding out the amount of water present in the pores. The membrane layer thickness was found to be 3 micron and the porosity was found out to be 0.38. The pore charge density was estimated from the particle charge density, pore density, pore diameter and the thickness of the membrane layer.

A model of binding forces in metals and alloys, based on the density functional theory and accounted effects of the many-body interactions, was proposed. The developed method can be easily applied for study of metals and alloys by the molecular dynamics simulation. The potentials of interatomic interactions have been found by the proposed method and applied for calculations of equation of state, elastic moduli and phonon dispersion in metals Ni, Al, alloys NiAl and Ni3Al. Results of the calculations are in good agreement with known experimental data both for pure metals and alloys.

In this study the complexes of salicylaldehyde thiosemicarbazone with Pd, Cu and Ru were prepared. The prepared complexes were characterized by spectroscopic, element and thermal analyses and D.C. conductivity measurement. The antimicrobial activity of all the prepared compounds against gram-positive, gram-negative and fungi was studied. From these studies, it has been obtained that the ligand is bonded to the metals through O, N and S, but to palladium in [Pd(H2L2)]Cl2 only through N and O. Biological studies confirm that the organic effect on both gram-positive and gram-negative bacteria is very weak and their complexes have no effect on fungi, but Cu-complex has strong influence on both types of bacteria.

Ultrafine particles prepared by evaporating pure Fe in CH4 atmosphere using arc-dischargeheating method, were found to consist of Fe-C solid solution, γ-Fe and Fe3C phases. EfFect of annealing temperature on phase transformation and hyperfine interactions has been investigated by Mossbauer spectroscopy, X-ray diffraction (XRD), differential thermal analysis and thermogravimetry (DTA-TG), transmission electron microscopy (TEM), oxygen determination and vibrating sample magnetometer (VSM) measurements. It was observed that phase transformation of γ-Fe to α-Fe occurs during annealing in vacuum. The mechanism causing the change of hyperfine interactions with annealing temperature differs for Fe-C solution and interstitial compounds. DifFerence of hyperfine interactions of Fe-C solid solution in the starting sample and its annealed samples is ascribed to the improvement of activation of interstitial carbon atoms. Stress-relieving in structure of annealed Fe3C particle can result in a weak influence on hyperfine interactions. Parameters fitted to the Mossbauer spectra show the existence of superparamagnetism in all the samples. Absorbed and combined oxygen on particle surface of the starting sample were determined.

The magnetocrystalline anisotropies of RFe10V2 (R=Y, Tb, Dy, Ho and Er) and their hydrides were studied by X-ray diffraction, magnetization and a.c. susceptibility measurements. The uniaxial anisotropy of Fe-sublattice and R-sublattice with positive second order Stevens αJ in RFe10V2 compounds is weakened by hydrogenation, while that of R-sublattice with negative αJ (Er) enhanced. Such a change of anisotropy causes planar-easy magnetic structures in RFe10V2 (R=Tb and Dy) at room temperature and induces spin reorientation in HoFe10V2 after hydrogenation. The change of anisotropy of R-sublattice after hydrogenation may be owed to a decrease of the second order crystalline coefficient.

The electrolytic domain boundary (EDB) of doped ceria between ionic and electronic conduction is theoretically investigated with the consideration of defect association. Data from the early reports on EDB of singly, double and triply doped ceria are summarized and interpreted based on the theoretical investigation. It is proposed that samarium and gadolinium among the rare earth elements are mostly suitable for the main dopants of ceria, while further minor additions of other elements can benefit the improvement of the EDB.

The fracture behaviour of glass in biaxial stress state has been investigated. Fracture toughness of disk specimen with a straight-through crack was measured under biaxial tension and uniaxial tension loads respectively. The difference between them and the reasons for the difference are discussed. The influence of the stress parallel to crack on fracture of brittle material was demonstrated in theory and experiments. The results show that plane stress fracture toughness of glass is not a material constant. and that the fracture toughness measured in biaxial tension state is higher than that measured under uniaxial tension. The conventional fracture criterion upon the stress intensity factor is questioned in the case of biaxial stress problem, and the strain dependence of crack growth is discussed.

From a molecular-dynamics simulation study on the rapid cooling process of liquid metal Al, it is demonstrated that the microscopic structure transitions is mainly determined by the changes of various microstructural configurations. There are tWo obvious phase transition points during the rapid cooling process. The first transition point is consistent with the well-known glass transition. The second one is a new weaker transition at low temperature. The cluster having 7-fold symmetry still exists in the supercooled liquid metal Al, though it occupies only 0.1% of the total number of clusters in the system and disappears below 550K, namely, it can not exist in the glassy state. These results will give us a new way to understand the structural transition at microscopic level.

Serrated flow has been investigated in binary Al-Li single crystals treated from as-quenched to overaged conditions. Serrations were observed during the deformation of crystaIs aged from 10to 100 h at 448 K. but not in the as-quenched and naturally aged conditions. The number of stress drops for serrations persistently increases within small stress drop limits as ageing time increases until attainment of peak-aged condition. Crystal orientations have some effects on stress drops for serrations.

Nanocrystalline aluminum nitride (whisker and particle) has been synthesized by heating the mixed aluminum+aluminum nitride ultrafine powders (UFPs) produced by nitrogen plasmamolten aluminum reaction, under N2 atmosphere at lower temperature. Some bamboo-like nano- whiskers of aluminum nitride were observed in TEM, the possible formation mechanism of the whiskers was also disucssed.

Characteristics of the precipitate α″-Fe16N2 phase have been investigated by X-ray diffraction and TEM analysis. VSM measurements give the saturation magnetization of the α″ phase.

The behaviour of passing solitary waves through the region of grain boundary has been investigated on the basis of the molecular dynamics method. It has been shown that solitary waves initiated by compression and shear loading have a different interaction with the grain boundary region. The possibilities of using solitary waves for nondestructive testing of materials, in particular, for testing the quality of coatings, for testing of accumulation of microdamages, etc. have been noted.

A new approach to isothermal precipitation kinetics of carbides in undercooled austenite has been proposed firstly, which is based on measuring the changes of Ms point vs holding time at a certain temperature. The isothermal precipitation kinetics (PTT) Curve of carbides was obtained by the use of the method for 13Cr-8Mn-0.07N stainless steel, and compared with the results of chemical phase analysis and TEM method. The results show that the new method is more sensitive and convenient than the other methods.