Photo-Driven Iron-Induced Non-Oxidative Coupling of Methane to Ethane

Photo-driven CH₄ conversion to multi-carbon products and H₂ is attractive but challenging, and the development of efficient catalytic systems is critical. Herein, we construct a solar-energy-driven redox cycle for combining CH₄ conversion and H₂ production using iron ions. A photo-driven iron-induced reaction system was developed, which is efficient at selective coupling of CH₄ as well as conversion of benzene and cyclohexane under mild conditions. For CH₄ conversion, 94 % C₂ selectivity and a C₂H₆ formation rate of 8.4 μmol h⁻¹ is achieved. Mechanistic studies reveal that CH₄ coupling is induced by hydroxyl radical, which is generated by photo-driven intermolecular charge migration of an Fe³⁺ complex. The delicate coordination structure of the [Fe(H₂O)₅OH]²⁺ complex ensures selective C−H bond activation and C−C coupling of CH₄. The produced Fe²⁺ can be used to reduce the potential for electrolytic H₂ production, and then turns back into Fe³⁺, forming an energy-saving and sustainable recyclable system.     

Quantification of polychlorinated dibenzo-p-dioxins and dibenzofurans by direct injection of sample extract into the comprehensive multidimensional gas chromatograph/high-resolution time-of-flight mass spectrometer

Polychlorinated dibenzo-p-dioxins and dibenzofurans in crude extracts of fly ash and flue gas from municipal waste incinerators were quantified using a comprehensive multidimensional gas chromatograph (GC x GC) coupled to a high-resolution time-of-flight mass spectrometer (HR-TOFMS). For identification and quantification, we developed our own program to prepare 3D chromatograms of selected mass numbers from the data of the GC x GC/HR-TOFMS. Isolation of all congeners with a TCDD toxic equivalency factor from the other isomers by only one injection was confirmed. The instrumental detection limit of TCDD on the GC x GC/HR-TOFMS was 0.9 pg by the relative calibration method. Quantification of these substances in the crude extracts was achieved by direct injection to the GC x GC/HR-TOFMS. The results agree with the values obtained using a generic gas chromatography/high-resolution mass spectrometry (GC/HRMS) system. It was confirmed that measurement by high-resolution TOFMS and GC x GC effectively reduces interference from other chemicals.     

Self-assembly of parallel atomic wires and periodic clusters of silicon on a vicinal Si111 surface

Silicon self-assembly at step edges in the initial stage of homoepitaxial growth on a vicinal Si(111) surface is studied by scanning tunneling microscopy. The resulting atomic structures change dramatically from a parallel array of 0.7 nm wide wires to one-dimensionally aligned periodic clusters of diameter approximately 2 nm and periodicity 2.7 nm in the very narrow range of growth temperatures between 400 and 300 degrees C. These nanostructures are expected to play important roles in future developments of silicon quantum computers. Mechanisms leading to such distinct structures are discussed.     

Simulation of mid-air images using combination of physically based rendering and image processing

Optical Review - Although it is beneficial to use an optical simulator to design a mid-air imaging system, the use of a simulator requires optical knowledge, and it cannot be handled by...     

Higher dimensional extensions of substitutions and their dual maps

Given a substitution σ ond letters, we define itsk-dimensional extension,E _k (σ), for 0≤k≤d. Thek-dimensional extension acts on the set ofk-dimensional faces of unit cubes inR ^d with integer vertices. The extensions of a substitution satisfy a commutation relation with the natural boundary operator: the boundary of the image is the image of the boundary. We say that a substitution is unimodular (resp. hyperbolic) if the matrix associated to the substitution by abelianization is unimodular (resp. hyperbolic). In the case where the substitution is unimodular, we also define dual substitutions which satisfy a similar coboundary condition. We use these constructions to build self-similar sets on the expanding and contracting space for an hyperbolic substitution.     

Influence of relaxation phenomena in dynamic magnetization processes on magnetic power losses of non-oriented electrical steel sheets

We have reported that the magnetic power losses per magnetizing cycle change with the magnetization pausing time in a constant rate of magnetization change and some relaxation phenomena exist in the magnetization pausing period. We discuss the influence of the relaxation phenomena on the dynamic magnetic power losses and suggest that the relaxation phenomena seems to be causes of the frequency dependence of the magnetic losses and of the variation of losses that cannot be expressed only by magnetization speed dependence of losses.     

Electronic structures of single-walled carbon nanotubes encapsulating ellipsoidal C70

The molecular orientation of ellipsoidal C(70) in single-walled carbon nanotubes (SWCNTs) depends on the tube diameter (d(t)). Photoluminescence (PL) studies reveal that the fullerene encapsulation effects on the optical transition energy of SWCNTs are significantly different for C(70) and C(60) at d(t) = 1.405-1.431 nm. This indicates that the transition from the "lying" alignment to the "standing" alignment occurs at d(t) ≈ 1.41 nm and the electronic states of SWCNTs are very sensitive to the interspacing between the encapsulated molecules and the SWCNTs. The present findings suggest that the electronic structure of SWCNTs is tunable not only by alternating the encapsulated molecules but also by controlling their molecular orientations, thus paving the way for development of novel SWCNT-based devices.     

Molecules participating in insect immunity of Sarcophaga peregrina

Pricking the body wall of Sarcophaga peregrina (flesh fly) larvae with a needle activated the immune system of this insect and induced various immune molecules, including antibacterial proteins, in the hemolymph. In this review, I summarize and discuss the functions of these immune molecules, with particular emphasis on the dual roles of some of these molecules in defense and development.     

Some electronic properties and morphological features of hybrid material DNA–SWCNT thin films

Thin films of hybrid material (ssDNA–SWCNT) prepared by ultrasonic mixing of both materials in water have been examined from the viewpoint of electrical, magnetic and optical properties, and morphological features to probe the possibly induced novel functions due to mutual interactions. Enclosing of DNA molecules inside a SWCNT is confirmed by the image and its motion. The temperature dependence of electrical resistivities is best-fitted to the two-dimensional variable-range-hopping regime. The radial breathing mode of the Raman spectra of the SWCNT exhibits significant modification due to interaction with DNA. The expected change in magnetic susceptibilities is not found in this case.