Layer architecture in 4‐nitro­phenyl and 4‐chloro­phenyl 3‐nitro­benzene­sulfonate at 100 K

The structures of the title compounds, C₁₂H₈N₂O₇S and C₁₂H₈ClNO₅S, contain weak C—H⋯O interactions creating layers of mol­ecules which, taking the conformation of the mol­ecules into account, are arranged in an ABAB sequence. Both structures can be designated, therefore, as ordered racemates of rotameric species.     

High-pressure studies on electronic and mechanical properties of FeBO3 (B = Ti,Mn, Cr) ceramics – a first-principles study

Using the density functional theory (DFT) method, the electronic and mechanical properties of perovskites FeBO₃ (B = Ti, Mn, Cr) nanostructures were studied in the pressure range of 0–100 GPa. The band structure studies show the change in the band structure upon substitution of different B cation in FeBO₃ perovskite structure. The density of states spectrum gives the perception of change in the electronic properties of FeBO₃ with the substitution of B cation. The bulk, shear and Young's moduli were calculated and an increase in the moduli is noticed. Moreover, the hardness increases under high pressure. The high-pressure studies of FeBO₃ perovskite nanostructures are explored at atomistic level. The findings show that ductility and hardness of FeBO₃ get increased upon an increase in the applied pressure. The substitution of Ti, Mn and Cr on FeBO₃ shows a significant change in the electronic and mechanical properties.     

Minimal classical communication and measurement complexity for quantum information splitting of a two-qubit state

We investigate the usefulness of the highly entangled five-partite cluster and Brown states for the quantum information splitting (QIS) of a special kind of two-qubit state using remote state preparation. In our schemes, the information that is to be shared is known to the sender. We show that, QIS can be accomplished with just two classical bits, as opposed to four classical bits, when the information that is to be shared is unknown to the sender. The present algorithm, demonstrated through the cluster and Brown states is deterministic as compared to the previous works in which it was probabilistic.     

Conformation of the methyl group and tetrahydropyridine ring in N-acyltetrahydroquinaldine derivatives

NMR spectra of N-acyletrahydro quinaldines 12–19 and of pyridodibenzoxazepines 21–24 show the Me group to be axially oriented with the tetrahydropyridine ring in a half-boat conformation. The aroyl phenyl in both is twisted out of the CO plane. While the Me group again occupies the axial position in pyridophenanthridones 5 and 7 and pyridooxazinones 8 and 9, the tetrahydropyridine ring exists as a half-chair.     

Shrinkages of the internuclear distances in some hexafluorides of octahedral symmetry

A brief analysis of the shrinkages or shortening of the internuclear distances in many molecular systems has been made. Analytical expressions for the linear shrinkage and nonlinear shrinkage have been derived in terms of the meansquare perpendicular amplitudes. Analytical expressions for the generalized mean-square amplitudes (mean-square parallel amplitudes, mean-square perpendicular amplitudes, and mean cross products) for an octahedralXY ₆ molecule have been given in terms of the mean-square amplitude matrices. The linear and nonlinear shrinkages for the hexafluorides of sulfur, selenium, tellurium, molybdenum, technetium, ruthenium, rhodium, tungsten, rhenium, osmium, iridium, platinum, uranium, neptunium, and plutonium have been computed at 298°K and 500°K, and the results have been briefly discussed.This paper is based on a thesis to be submitted byThomas S. Adams to the Graduate School of the Valdosta State College in partial fulfillment of the requirements for the degree of Master of Science.     

Low-lying dipole strength for weakly bound systems: A simple analytic estimate

A simple analytic expression is proposed for the total low-lying dipole strength observed in the break-up of weakly bound systems. The model assumes pure single-particle transitions from the halo weakly bound state to continuum states treated as plane waves (neutrons) or regular Coulomb functions (protons). The analytic expression for the total strength approximately depends on the inverse of the binding energy and the reduced mass of the halo, with correction factors accounting for the charge of the halo and the finite size of the potential.     

Gel mechanics: a comparison of the theories of Biot and Tanaka, Hocker, and Benedek

This article compares the Biot [J. Appl. Phys. 12, 155 (1941)] and Tanaka, Hocker, and Benedek (THB) [J. Chem. Phys. 59, 5151 (1973)] theories of gel deformation. Biot's theory treats the gel as a continuum with the pore pressure as a state variable whereas the THB theory treats the gel as a mixture of solid and liquid phases. We revisit the problem of gel deswelling and use this example to show that there can be substantial differences between the two theories. The THB theory is not a complete mixture theory since the displacements of the liquid are assumed to be negligibly small in comparison with the displacements of the network. We propose a simple extension of the THB model, which takes into account the momentum transfer of the liquid phase. We show that with this simple addition and some very reasonable assumptions, the extended THB theory is identical to the Biot theory.     

A study of the PE–PTFE system. II. ESCA measurements

Samples of polyethylene and polytetrafluorethylene were sintered at 200°C. The samples were cleaved and cut, and the two types of surfaces were studied by ESCA. The possibility of chemical interaction between the two polymers and the formation of a transitional layer is postulated on the basis of the results. A morphological model of the structure of these samples is given.     

A finite element approach to the design and dynamic analysis of platform type robot manipulators

The design of a closed-loop platform-type robot manipulator using the finite element method is presented. The present approach aims at the optimization of the manipulator geometry and prediction ot the actuator parameters. Beam elements and triangular plate elements are used for the finite element model. Manipulators having six spherical-prismatic-spherical (6 SPS) pairs and of tetrahedron construction have been compared for their dynamic performance.