Isothermal vapor-liquid equilibria for the binary systems propylene-carbon dioxide,propylene-ethylene and propylene-ethane at high pressure

isothermal vapor-liquid equilibria for the binary systems propylene-carbon dioxide, propylene-ethylene and propylene-ethane have been measured at 283.15 and 298.15 K using a static method.The equilibrium data obtained have been correlated with the total-pressure method using both the Redlich-Kwong equation of state modified by Soave and the perturbation equation proposed by Gubbins and Twu. From normal probability plots of the residuals in the correlations versus the theoretical residuals in the normal distribution, the applicability of each of these two equations has been tested statistically.Furthermore, the fugacity coefficients calculated from the virial equation have been compared with those obtained from the correlations for the low-pressure regions.     

Water-assisted oxo mechanism for heme metabolism

A mechanism of heme metabolism by heme oxygenase (HO) is discussed from B3LYP density functional theory calculations. The concerted OH group attack to the alpha-carbon by the iron-hydroperoxo species is investigated using a model with full protoporphyrin IX to confirm our previous conclusion that this species does not have sufficient oxidizing power for heme oxidation (J. Am. Chem. Soc. 2004, 126, 3672). Calculated activation energies and structures of the intermediates and transition state for this process remain unchanged from those for a small model with porphine in the previous study, which shows that the inclusion of the side chain of the porphyrin ring is not essential in describing the OH group transfer. The activation barrier for a direct oxo attack to the alpha-carbon by an iron-oxo model is calculated to be 49.8 kcal/mol, the barrier height of which looks very high for the enzymatic reaction under physiological conditions. This large activation energy is due to a highly bent porphyrin structure in the transition state. However, a bridging water molecule plays an important role in reducing the porphyrin distortion in the transition state, resulting in a remarkable decrease of the activation barrier to 13.9 kcal/mol. A whole-enzyme model with about 4000 atoms is constructed to elucidate functions of the protein environment in this enzymatic reaction using QM/MM calculations. The key water molecule is fixed in the protein environment to ensure the low-barrier and regioselective heme oxidation. A water-assisted oxo mechanism of heme oxidation by heme oxygenase is proposed from these calculational results.     

SO(N) supergravity and unification of all fundamental forces

From the group theoretical arguments, we find that among allSO(N) supergravitiesN=10 is the minimal supersymmetry group which unifies all fundamental forces of weak, electromagnetic, strong and gravitational interactions. The (super)symmetry is broken throughSO(10)→SU(3)?SU(2)?U(1)→SU(3)?U(1). All observed particles of the low energy physics (three generations of quarks and leptons, γ,Z, W ^± and gluons) and graviton can be minimally accomodated with the correctSU(3)?SU(2)?U(1) quantum numbers. Some characteristic predictions, which can be checked in the coming high energy experiments, are briefly discussed.     

Tripodal oxazoline-based homochiral coordination cages with internal binding sites

Homochiral coordination cages, which have two well-defined internal binding sites for ammonium and organoammonium ions, have been constructed by Pd(II)-mediated self-assembly of preorganized tripodal oxazolines containing pyridine pendant groups.     

Super Yang–Mills theory from nonlinear supersymmetry

The relation between a nonlinear supersymmetric (NLSUSY) theory and a SUSY Yang–Mills (SYM) theory is studied for N=3$N=3$ SUSY in two-dimensional space–time. We explicitly show the NL/L SUSY relation for the (pure) SYM theory by means of cancellations among Nambu–Goldstone fermion self-interaction terms.     

Effect of high-pressure ammonia treatment on the activity of Ge3N4 photocatalyst for overall water splitting

The photocatalytic activity of beta-Ge(3)N(4) powder for overall water splitting is successfully enhanced by ammonia treatment at 823 K for 5-24 h at ammonia pressures of 20 MPa or greater. The surface and bulk nitrogen content in the treated samples varies according to the treatment temperature and treatment time, related to the stability of beta-Ge(3)N(4) powder under pressurized ammonia. The change in nitrogen content resulted in a change in the photocatalytic activity for overall water splitting. A beta-Ge(3)N(4) powder treated at 823 K for 5 h under ammonia at 20 MPa exhibited a photocatalytic activity 4 times higher than that of the as-synthesized powder, attributable to a decrease in the density of anion defects in the bulk and surface.     

Core–Shell‐Structured LaTaON2 Transformed from LaKNaTaO5 Plates for Enhanced Photocatalytic H2 Evolution

LaTaON₂ is a photocatalyst with intense visible light absorption up to 650 nm, but exhibits low H₂ evolution activity owing to uncontrolled facets and high defect densities. In this work, core–shell‐structured plate‐like LaKNaTaO₅/LaTaON₂ was synthesized by nitriding a layered perovskite‐type LaKNaTaO₅. The volatilization of K and Na species during the nitridation promoted the rapid transformation of LaKNaTaO₅ into LaTaON₂ along [010] direction with the plate‐like shape retained. This yielded high‐quality LaTaON₂ shells exposing (010) facets on the lattice‐matched LaKNaTaO₅ cores. After loading with a Rh co‐catalyst, LaKNaTaO₅/LaTaON₂ showed photocatalytic H₂ evolution activity four times greater than that obtained from conventional irregular‐shaped LaTaON₂ powders and utilized visible light up to 620 nm. This work provides a novel strategy yielding oxynitrides with well‐defined facets and low defect densities by selecting lattice‐matched oxide precursors containing volatile components.     

Molecular understanding of the adhesive interactions between silica surface and epoxy resin: Effects of interfacial water

The molecular mechanism of the adhesion between silica surface and epoxy resin under atmospheric conditions is investigated by periodic density-functional-theory (DFT) calculations. Slab models of the adhesion interface were built by integrating a fragment of epoxy resin and hydroxylated (0 0 1) surface of α-cristobalite in the presence of adsorbed water molecules. Effects of adsorbed water on the adhesion interaction are evaluated on the basis of geometry-optimized structures, adhesion energies, and forces. Calculated results demonstrate that adsorbed water molecules significantly reduce both the adhesion energies and forces of the silica surface–epoxy resin interface. The reduction of adhesion properties can be associated with structural deformation of water molecules confined in the tight space between the adhesive and adherend as well as structural flexibility of the hydrogen-bonding network in the interfacial region during detachment of the epoxy resin from the hydrophilic silica surface. © 2018 Wiley Periodicals, Inc.     

Direct and stepwise energy transfer from excitons to plasmons in close-packed metal and semiconductor nanoparticle monolayer films

We studied the dynamics of photoluminescence (PL) and energy transfer in close-packed monolayer films of CdSe and Au nanoparticles (NPs) assembled using the Langmuir-Blodgett technique. The PL intensity and dynamics depended on the ratio of CdSe to Au NPs in the mixed films. The PL quenching of CdSe NPs occurs through rapid energy transfer from excitons in CdSe NPs to plasmons in Au NPs. The PL decay curves of the mixed NPs monolayers are determined by three decay rates: the direct energy transfer between the nearest-neighbor CdSe and Au NPs (CdSe-->Au), the stepwise energy transfer from CdSe to CdSe to Au NPs (CdSe-->CdSe-->Au), and the radiative recombination in CdSe NPs.