Movement Of Free Electrons Research Articles

Corrosion characteristics of in situ hybrid (Al3Ni + Al2O3)/Al composites synthesized by the solid-state combustion

Abstract In this study, in situ hybrid (Al3Ni + Al2O3)/Al composites were prepared successfully by the solid-state combustion via Al–NiO system. The effects of Al3Ni + Al2O3 on the corrosion features of composites were analyzed using potentiodynamic polarization, electrochemical impedance spectroscopy, and immersion corrosion in 3.5 wt% NaCl solution. The results show that with the increase of NiO addition, the corrosion resistance of composites is improved, and the corrosion resistance of 15 % NiO–Al composite is almost comparable to the Al matrix. The increased quantity and dispersive distribution of Al3Ni and Al2O3 particles can effectively prevent the occurrence of corrosion and the movement of free electrons. Besides, more fine Al2O3 particles distributed in grain boundaries can increase the impedance and hinder the electrochemical corrosion preferentially starting at the boundary. Also, in the composite with high NiO addition, a better and compact interface bonding can be formed due to reduction of large size Al3Ni particles and improvement in the dispersion of particles, thereby inhibiting interface damage. This study has advanced understanding of corrosion.

Переменный электрический ток в угольных шахтах: электромагнитная энергия и превращение её в электрический ток

The article addresses the challenge of improving the competence and basic knowledge of specialists working with alternating electric current. The purpose of this work is to explain the magnetic properties of substance, generation of magnetic field and electric current with due account for the known laws of physics and the Quantum theory. We believe that addressing these tasks needs to begin with the energy produced by the magnet. The method of inducing electric energy using magnetic field of a permanent magnet is chosen as the research subject. The historical mythological bases of interpreting the induction of electric energy are shown. Modern instruments prove that the magnetic field is the electromagnetic emissions of magnets. A hypothesis regarding the origin of magnetic properties of substance is developed based on analysis of the known magnetic properties of alpha-iron. Two features of the magnetic properties of substance have been revealed, which differ from Ampere's ideas. The first is the local volume of atoms combined by short-acting covalent bonds, forming a natural crystalline or artificially elongated structure. The second is that the frequency of electromagnetic emissions by the valence electrons of all the atoms in Hertz is approximately the same. The total radiation of energy by all the atoms in local formations generates a magnetic field. The hypothesis is confirmed by circuits and information on instruments that measure the emission of magnets in Hertz. When the energy absorbed by electrons increases, the bond between atoms is broken and magnetic emissions cease. All substances in liquid and solid aggregate state begin to radiate electromagnetic emissions to other substances under the impact of external electromagnetic emissions. This is confirmed by photographic evidence of the performed experiments. A hypothesis is proposed, which differs from the ideas about the movement of free electrons by the fact that the formation of electric current is the result of absorbing electromagnetic emissions of the magnet by valence electrons of the electrical conductor and their transfer into the electric network. The physical phenomena of energy transfer between the transformer windings in an electric circuit prove that electric current is a concentrated flow of electromagnetic emissions, which are a wave form of energy.

Using Regression Analysis to Optimize the Combination of Thermal Conductivity and Hardness in Compacted Graphite Iron

In cast iron there is a contradictory relationship between thermal conductivity and strength. In many applications it is desirable to optimize the material properties to obtain both sufficiently high thermal conductivity and sufficiently high strength. The aim of this paper is to investigate how various microstructure parameters and alloying elements affect thermal conductivity and hardness in compacted graphite irons. It was found that the fraction of ferrite, the fraction of cementite, nodularity and content of carbon and silicon are parameters that influence the thermal conductivity and hardness the most. Based on these five key parameters linear regression equations were created for calculation of thermal conductivity and hardness. Ferrite and carbon have a positive influence on the thermal conductivity, while silicon, cementite and nodularity have a deleterious effect. All parameters except ferrite have a positive influence on the hardness. This is because the thermal conductivity is dependent on the movement of free electrons, and therefore unfavourable growth directions and grain boundaries which impede the electron movement will reduce the thermal conductivity. Ferrite has quite high thermal conductivity, while cementite has poor thermal conductivity, due to an unfavourable crystal structure. Nodular shaped graphite has a lower thermal conductivity than compacted graphite which explains the deleterious influence of nodularity. The soft ferrite phase will reduce the hardness value, while increasing the fraction of harder graphite nodules and harder cementite phase will increase the hardness. To investigate how these five parameters affect the combination of hardness and thermal conductivity, values for hardness and thermal conductivity were calculated for all combinations of key parameters in given intervals, using two linear regression equations. From these it is possible to predict the combination of parameters which gives a particular combination of hardness and thermal conductivity in compacted graphite iron.

Electronic structure of BN nanotubes with intrinsic defects N B and B N and isoelectronic substitutional impurities P N, As N, Sb N, In B, Ga B, and Al B

The effect of intrinsic defects and isoelectronic substitutional impurities on the electronic structure of boron-nitride (BN) nanotubes is investigated using a linearized augmented cylindrical wave method and the local density functional and muffin-tin approximations for the electron potential. In this method, the electronic spectrum of a system is governed by a free movement of electrons in the interatomic space between cylindrical barriers and by a scattering of electrons from the atomic centers. Nanotubes with extended defects of substitution N B of a boron atom by a nitrogen atom and, vice versa, nitrogen by boron B N with one defect per one, two, and three unit cells are considered. It is shown that the presence of such defects significantly affects the band structure of the BN nanotubes. A defect band π(B, N) is formed in the optical gap, which reduces the width of the gap. The presence of impurities also affects the valence band: the widths of s, sp, and p π bands change and the gap between s and sp bands is partially filled. A partial substitution of the N by P atoms leads to a decrease in the energy gap, to a separation of the Ds(P) band from the high-energy region of the s(B, N) band, as well as to the formation of the impurity Dπ(P) and Dπ*(P) bands, which form the valence-band top and conduction-band bottom in the doped system. The influence of partial substitution of N atoms by the As atom on the electronic structure of BN nanotubes is qualitatively similar to the case of phosphorus, but the optical gap becomes smaller. The optical gap of the BN tubule is virtually closed due to the effect of one Sb atom impurity per translational unit cell, in contrast to the weak indium-induced perturbation of the band structure of the BN nanotube. Introduction of the one In, Ga or Al atom per three unit cells of the (5, 5) BN nanotube results in 0.6 eV increase of the optical gap. The above effects can be detected by optical and photoelectron spectroscopy methods, as well as by measuring electrical properties of the pure and doped BN nanotubes. They can be used to design electronic devices based on BN nanotubes.

418 自由電子の運動を取り入れた分子動力学法による一般化された熱伝導理論のパラメーターの推定(OS05-5 ポテンシャルと熱伝導)(OS05 電子・原子シミュレーションに基づく材料特性評価)

418 自由電子の運動を取り入れた分子動力学法による一般化された熱伝導理論のパラメーターの推定(OS05-5 ポテンシャルと熱伝導)(OS05 電子・原子シミュレーションに基づく材料特性評価)

An Interstitial-Electron Model for the Structure of Metals and Alloys. V. Metal Alloys and Intermetallic Compounds

Abstract On the basis of the interstitial-electron model for metals the essential feature of the metallic state is the relatively free movement of electrons, (\bare), between interstices in a close-packed array of metal ions (positive cores). For a solid solution of one metal in another in which the metal ions have nearly the same size and core charge, the interstitial-electron structures which incorporate spatial and spin correlation of electrons are the same as for metals. Metallic properties can also result when the ratios of two less similar metals in an alloy are such as to give interstices with a constant ratio of the two metals surrounding them. Occupancy of such “homogeneous interstices” is the basis for intermetallic compounds and accounts for the Hume-Rothery rules. Intermetallic compounds such as γ phases (e.g. Cu5Zn8) are unique in that \bare and electron pairs must be assigned to two or more types of interstices which have different ratios of the two metal ions around them. This localization of \bare density explains the very poor conductivity, the hardness, the brittleness and the large diamagnetic susceptibility of γ phases. The structural framework of the interstitial-electron description accounts for the large composition range of the interstitial phases and can naturally include effects of ion core size and charge. Interpenetration of d10 ion cores by itinerant electrons which gives a balancing of the positive fields of the 2 ion cores accounts for the preponderance of d10 metals among intermetallic phases.