Measurement of Electrical Conductivity of Porous Titanium and Ti6A14V Prepared by the Powder Metallurgy Method

Porous titanium and Ti6A14V are produced by the powder metallurgy method. Dependence of the electrical conductivity on the porosity and pore size is investigated and the experimental results are correlative and compared with several earlier models. A newly modified Mori-Tanaka relationship based on the effective field method is proposed, which is successfully applied to describe the dependence of the electrical conductivity of porous titanium and Ti6A14V on the porosity. The pore size has a minor effect on the electrical conductivity of both samples.     

The Influence of Phase Composition and Phase Distribution on Crack Formation and Fracture Mechanisms of Cr–Ni Steels Produced by the Method of 3D Electron-Beam Printing

Russian Physics Journal - The features of crack formation near the fracture region and the fracture micromechanism are investigated during uniaxial tension of specimens of Ni–Cr stainless...     

Review of magnetic features observed in (A,A′)Ni2B2C solid solutions

The nickel-borocarbides ANi₂B₂C [A=Y, Ln (lanthanide), An(actinide)], crystallizing in the body-centred tetragonal LuNi₂B₂C-type structure, are classified according to the existence or coexistence of superconducting and antiferromagnetic states (AF). The magnetic features observed in polycrystalline (A,A′)Ni₂B₂C solid solutions, adopting the same crystal structure, are reviewed and discussed. Published data on the magnetism in (A,Ln)Ni₂B₂C systems (ANi₂B₂C nonmagnetic, A=Y,La,Lu) indicate a gradual rise in the threshold content, x(m), in (Y_1−xLn_x)Ni₂B₂C (Ln=Gd,Tb,Dy,Ho,Er) for the establishment of AF states. (A,A′)Ni₂B₂C systems with magnetic end compounds show gradual variation in magnetic features when A and A′ are both heavy Ln. The behaviour of (A,A′)Ni₂B₂C systems of light A (Pr or U) and heavy A′ (Dy or Tm) depends on the magnetic structures of the end compounds. In intermediate compositions, incomplete moment compensation in (Pr,Dy)Ni₂B₂C decreases T_N, while different moment directions in the end compounds in (U,Dy)Ni₂B₂C lead to a directional frustration of ordered moments. Such a frustration in (U,Tm)Ni₂B₂C is related to different magnetic structures of the end compounds.     

A study of the role of the Δ-resonance in the reaction 13C(γ,π−)13Ngs

Cross sections for the exclusive photoproduction reaction ¹³C(γ,π⁻)¹³N_gs were measured at energies across the resonance region. To focus on the resonant production mechanism the measurements were carried out at a fixed nuclear momentum transfer of Q = 1 fm⁻¹. For a test of the non-resonant production and of the nuclear transition matrix element, data at Q = 1.25 fm⁻¹ and a differential cross section at 223 MeV photon energy were taken. There are sizeable discrepancies between our measurements and the theoretical predictions.     

A study of the alloying behaviour of Ni–B amorphous catalysts using Auger parameter measurements,and primary and secondary features of the XPS spectrum

Electrodeposited Ni–B alloys of nominal compositions 30?at.% B and 50?at.% B, which were developed as catalysts for the electrolytic hydrogen production process, were studied using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The Ni–B alloys were found to be amorphous. Changes of Auger parameter (AP) values and information from the primary and secondary structure of the XPS spectrum were employed to probe the electronic changes occurring upon alloying. It is suggested that the main electronic change occurring is hybridisation of the Ni occupied states with the B?sp empty states and an apparent increase of the electron density around the Ni sites. The electron affinities of the two elements contradict their electronegativity tendencies. It is suggested that the contradiction may be resolved by considering the increase in the electron density at the Ni sites in the Ni–B alloys to be a result of shortening of the interatomic distances via the formation of hybridized bonds between Ni and B atoms.     

Formation of Mixture of A and C Centres in Diamond Synthesized with Fe90Ni10-C-High-Content Additive NaN3 by HPHT

Very rich nitrogen concentration with the dominant C centres and some A centres are found in diamonds grown from a Fe90Ni10-C-high-content NaN3 additive system. The concentrations of C centres rapidly increase with increasing content of NaN3 additive, while the concentrations of A centres increase slowly. The total nitrogen concentration tends to increase rapidly with increasing content of NaN3 additive when the content of NaN3 is below 0.7 wt%. However, the total concentration of nitrogen in the diamonds increases slowly when the content of NaN3 is further increased up to 1.0 wt%, and the total nitrogen average concentration are calculated to be around 2230ppm for most of the analysed synthetic diamonds. Eurthermore, the nitrogen impurities in different crystal sectors of the diamonds are inhomogeneously distributed. The nitrogen impurities in the diamonds in [111] zones are incorporated more easily than that in [100].     

Allotropic forms of carbon in the Invar Fe–Ni–C alloy before and after plastic deformation by upsetting

The effect of cold plastic deformation by upsetting (e = 1.13) on structure and hybridised bonds of carbon in the fcc Invar Fe-30.9%Ni-1.23% C alloy was studied by means of X-ray phase analysis and X-ray photoelectron spectroscopy. Carbon precipitates along grain boundaries and inside of grains in the alloy after annealing and plastic deformation were revealed. The presence of mainly sp²- and sp³-hybridised C–C bonds attributing to graphite and amorphous carbon as well as the carbon bonds with impurity atoms and metallic Fe and Ni atoms in austenitic phase were revealed in the annealed and deformed alloy. It was shown for the first time that plastic deformation of the alloy results in partial destruction of the graphite crystal structure, increasing the relative part of amorphous carbon, and redistribution of carbon between structural elements as well as in a solid solution of austenitic phase.     

Synthesis and Spectroscopic Characterizations of the Mono-and Bimolecular Iron(Ⅲ) Complexes by the Interaction With Tris Buffer in Neutralized Media: Biological and Morphological Investigations

The reaction of iron(Ⅲ) anions, FeCl_3 and Fe_2(SO_4)_3 with tris(hydroxymethyl) aminomethane(Tris) in a 1∶2 molar ratio affords the new coordination compounds NH_4[Fe_2(Tris)_2(H_2O)_4(SO_4)](Ⅰ) and NH_4[Fe(Tris)_2(H_2O)_2](Ⅱ). These compounds were characterized by elemental analysis, and their molecular structures were determined by spectroscopic methods(infrared and electronic spectra), magnetic susceptibility, and molar conductivity measurements, and further corroborated by thermo gravimetric analysis and its differential(TGA/DrTGA). According to the experimental data, the complexes can be characterized in the solid state as mono-and binuclear, with a distorted octahedral stereochemistry. The distorted octahedral stereochemistry adopted by the complexes was confirmed by the magnetic susceptibility measurement of NH_4[Fe_2(Tris)_2(H_2O)_4(SO_4)], which consists of a six-coordinate iron atoms in a distorted octahedral environment constructed from four O atoms(two Tris molecules), two O atoms from the loosely associated SO_4 coordinated ligand, and O, N of second Tris molecule with occupying by four oxygen atoms of coordinated water molecules. Regarding, NH_4[Fe(Tris)_2(H_2O)_2] complex the mono iron atom is surrounded by six oxygen atoms as four by two Tris molecules and two coordinated water molecules in axial form. Antibacterial and anticancer activities of the complexes were studied and the complexes were screened against bacteria, colorectal adenocarcinoma(Caco-2) and breast cancer(Mcf-7) cell lines.     

Hyperfine interactions of interstitial12B in Fe,V and Ta studied by use of the asymmetric β decay

Magnetic hyperfine fields and spin-lattice relaxation times of interstitial and substitutional¹²B nuclei in Fe are studied in a temperature range, 100 K<T<1200 K, by use of the asymmetric decay from the spin polarized nuclei and NMR detection. In order to infer information regarding the location of¹²B nuclei and expansion in the nearest Fe surrounding following recoil implantation, hyperfine interactions of¹²B in non-magnetic bcc V and Ta crystals are studied.     

Spin precession of Po in Ni detected by In-beam conversion electrons and the magnetic moment of the 15− isomer in204Po

The magnetic moment of the 11 ns, 15^? isomer in²⁰⁴Po and the internal magnetic field of Po in Ni were determined in an in-beam recoil implantation experiment. Time-differential perturbed angular distributions of conversion electrons were measured in an iron-free orange spectrometer. The magnetic hyperfine field of ¦H(PoNi)¦=555(22) kOe is in agreement with the systematic trend for the 6p elements. Theg-factorg(15^?) =0.41(2) is discussed, together with theB (E2, 15^?→13^?). within the shell model.     

A Method of É. Borel for calculation of the Thomas precession: The geometric phase in relativistic kinematic velocity space and its applications in optics

In 1913, É. Borel (1871–1956) considered the relativistic kinematic rotation of a body that arises in the course of its orbital motion. In order to determine the angular velocity of this rotation, Borel introduced the notion of a kinematic space and applied the Gauss-Bonnet formula for a sphere of a unit radius. However, at that time, his results did not find practical applications and, soon, were forgotten. After the discovery of electron spin by S.A. Goudsmit and G.E. Uhlenbeck in 1925, real interest in this phenomenon was rekindled, and it was considered once again by L.H. Thomas in 1926–1927, being termed the Thomas precession. The Thomas precession manifests itself mostly in optical phenomena.     

Study of the levels in 174Lu by (p, 3nγ) spectroscopy

The nuclear levels in ¹⁷⁴Lu were investigated by means of ¹⁷⁶Yb(p, 3nγ) reaction spectroscopy. Standard germanium detector techniques as well as an on-line curved crystal spectrometer were used. Six well-developed rotational bands are observed. These results confirm and extend the scheme previously obtained by direct reactions. The presented data document a study on the anomalous g-factors of the 142 d isomeric band.     

Formation of two pions on nuclei in A(γ, ππN)B reactions

A model is proposed for double pion photoproduction on nuclei that is accompanied by nucleon emission. Simple models that faithfully reproduce single-particle differential cross sections are used to describe photon interactions with intranuclear nucleons. The calculated cross sections for pion photoproduction on ¹²C nuclei are compared with inclusive pion spectra measured in the second resonance region of photon energies.