Rh and Ag are the neighboring elements with Pd that is famous for a hydrogen-storage metal. Although Rh and Ag do not possess hydrogen-storage property, can Ag–Rh alloys actually storage hydrogen? Ag–Rh solid-solution alloys have not explored in the past because they do not mix each other at the atomic level even in the liquid phase. The author has used the chemical reduction method to obtain such the Ag–Rh alloys, and XRD and STEM-EDX give clear evidence that the alloys mixed at the atomic level. From the measurements of hydrogen pressure-composition isotherms and solid-state 2H NMR, The author has revealed that Ag–Rh solid-solution alloys absorb hydrogen and the total amount of hydrogen reached a maximum at the ratio of Ag:Rh = 50:50, where the electronic structure is expected to be similar to that of Pd.

Hydrogen-Storage Properties of Solid-Solution Alloys of Immiscible Neighboring Elements with Pd

ConspectusCurrently 118 known elements are represented in the periodic table. Of these 118 elements, only about 80 elements are stable, nonradioactive, and widely available for our society. From the viewpoint of the “elements strategy”, we need to make full use of the 80 elements to bring out their latent ability and create innovative materials. Furthermore, there is a strong demand that the use of rare or toxic elements be reduced or replaced while their important properties are retained. Advanced science and technology could create higher-performance materials even while replacing or reducing minor or harmful elements through the combination of more abundant elements.The properties of elements are correlated directly with their electronic states. In a solid, the magnitude of the density of states (DOS) at the Fermi level affects the physical and chemical properties. In the present age, more attention has been paid to improving the properties of materials by means of alloying elements. In particular, the...

Creation of Novel Solid-Solution Alloy Nanoparticles on the Basis of Density-of-States Engineering by Interelement Fusion

The pseudopotential method within the virtual crystal approximation combined with the Harrison bond-orbital model were used to determine all three elastic constants, and hence Poisson's ratio of GaxIn1−xSb semiconductor alloys. Our results for parent compounds are compared to experiment and other theoretical calculations and showed generally good agreement. The effect of compositional disorder on the studied quantities has been examined. We found an important bowing in all elastic constants and bulk modulus versus Ga content. The Poisson ratio was found to be independent of alloy composition x.

Compositional dependence of the elastic constants and the Poisson ratio of GaxIn1−xSb

Thin cell layers of tobacco (three to six layers of epidermal and subepidermal cells) were allowed to float on the surface of a liquid medium. Whereas the control on an identical medium solidified by agar gave 100% of explant-forming flowers, no flowers formed in the absence of agar (100% of the explants formed buds). In order to initiate flower formation, various modifications of the liquid medium were tried: different ratios of indolyl-3-butyric acid (IBA) to kinetin (Kin) from 1 to 100, a range of pH from 4.0 to 7.0, and glass beads of different diameters (in an attempt to change the physico-chemical characteristics of the culture substrate itself). On a liquid medium with glass beads, four types of morphogenesis (flowers, buds, a mixed programme of flowers and buds, and a non-morphogenetic programme –i.e. the explants remained unchanged) were separately induced by changing one of the three factors: pH, IBA and Kin in equimolar concentrations, and diameter of the glass beads. Changing only the IBA/Kin ratio failed to provoke flower differentiation. pH of the medium was found to change after autoclaving and the effect of glass beads on morphogenesis was partly related to modification of pH.

In vitro control of de novo flower differentiation from tobacco thin cell layers cultured on a liquid medium

We have characterized by capacitance‐voltage and deep level transient spectroscopy measurements the only defect detected in Si‐doped GaInP layers. This defect exhibits an ionization energy of 0.435 eV but is located only at ∼20 meV below the bottom of the conduction band. All its characteristics, i.e., energy level, apparent capture barrier, ionization energy, can be understood if the defect is a donor associated DX center. Its cross section for electron and hole capture have been measured. The effect of an electric field on the ionization energy confirms that the defect is indeed shallow and a donor.

Defects in epitaxial Si‐doped GaInP

A CPA calculation of E1 optical gaps in III-V ternary alloys

Electronic band structures of the ternary alloys GaxIn1-xP, GaAs1-xPx, GaxIn1-xAs and InAs1-xPx are calculated in the coherent-potential approximation (CPA) using the tight-binding Hamiltonian. The CPA energy bands are reported for the first time for the GaxIn1-xAs and InAs1-xPx systems. The calculated variation of important direct and indirect energy gaps with composition x and their bowing is compared with the available experimental data, and good agreement is found for all the four ternary alloys studied.

https://iopscience.iop.org/article/10.1088/0953-8984/1/30/005/pdf

Rita Gupta

Papers

A CPA calculation of E1 optical gaps in III-V ternary alloys

Electronic structure of III-V ternary semiconductors

Many-body suppression of the X-ray resonant scattering in metals

Alloy contribution to phonon softening in ultra-heavily doped Si:As