In situ analysis of soybeans and nuts by probe electrospray ionization mass spectrometry

The probe electrospray ionization (PESI) is an ESI‐based ionization technique that generates electrospray from the tip of a solid metal needle. In the present work, we describe the PESI mass spectra obtained by in situ measurement of soybeans and several nuts (peanuts, walnuts, cashew nuts, macadamia nuts and almonds) using different solid needles as sampling probes. It was found that PESI‐MS is a valuable approach for in situ lipid analysis of these seeds. The phospholipid and triacylglycerol PESI spectra of different nuts and soybean were compared by principal component analysis (PCA). PCA shows significant differences among the data of each family of seeds. Methanolic extracts of nuts and soybean were exposed to air and sunlight for several days. PESI mass spectra were recorded before and after the treatment. Along the aging of the oil (rancidification), the formation of oxidated species with variable number of hydroperoxide groups could be observed in the PESI spectra. The relative intensity of oxidated triacylglycerols signals increased with days of exposition. Monitoring sensitivity of PESI‐MS was high. This method provides a fast, simple and sensitive technique for the analysis (detection and characterization) of lipids in seed tissue and degree of oxidation of the oil samples. Copyright © 2015 John Wiley & Sons, Ltd.     

High-order harmonic generation in nitrogen molecules with subpicosecond visible dye-laser pulses

An experimental study of high-order harmonic generation in nitrogen molecules (N₂) has been made using intense visible (616 nm) dye-laser pulses, where the harmonic radiation up to the 21st order is observed. The harmonic distribution represents a plateau that is preceded by an intensity minimum at the 7th order. The harmonic generation characteristics were atomic-like. It has been found that there are some similarities in the high-order harmonic generation characteristics for N₂ and Ar, including the highest-order harmonics, harmonic distributions, and the influence of the multiphoton ionization on the high-order harmonic generation. These similarities are reasonably attributed to the energetic correspondence of excited levels and ionization potentials. It is pointed out that the ac Stark shift of excited levels and ionization potentials plays an important role also in the high-order harmonic generation in N₂.     

Superlattice-like structure of sputter-deposited amorphous aluminum-heavy element alloys

Al---Zr, Al---Nb, Al---Mo, Al---Ta and Al---W alloys were prepared by DC magnetron sputtering using an Al target with embedded heavy metals disks and substrate rotating around their own central axes and revolving around the central axes of the sputtering chamber. They were examined with X-ray diffraction (XD) of the Cu K, and Al---Ta alloys were also observed by transmission electron microscopy (TEM). Within the diffraction angles, 2τ = 20° ≈ 90°, XD patterns of the examined specimens were all typical of the amorphous structure. However, at the small angle region, 2τ < 10°, a number of sharp diffraction peaks appeared. The lattice spacing obtained from the diffraction peaks was linearly dependent on the inverse of the revolution period of the substrate during the sputter deposition. TEM images showed a layered structure which corresponded to the lattice spacing detected by XD. It is concluded that the superlattice-like structure appearing in the sputter-deposited alloy films arises from the compositional heterogeneity in the sputtered flux of atoms, which comes from the large non-uniformity of the target structure and sputtering conditions.     

Self-Modulation of Scattering Intensity from a Silica Sphere Coated with a Sol-Gel Film Doped with J-Aggregates

A micrometer-sized nonlinear optical resonator constituted of a silica microsphere coated with J-aggregates has been fabricated by the sol-gel process. We determined the scattering light spectrum and discuss the application of the observed effect for the realization of an optical switching element. Optical evaluation of the sphere has been performed in the attenuated-total-reflection (ATR) configuration. We excited a whispering gallery mode and measured the nonlinear ATR signal dependence on excitation intensity. The experimental result agrees very well with the simulation results obtained using the Mie theory and the finite-difference time-domain method taking into account optical Kerr nonlinearity. The permittivity of the film of J-aggregates was measured by ATR method at several wavelengths and the value at the desired wavelength was determined by extrapolation using the Lorentz function.     

Crystallization and Reduction of Sol-Gel-Derived Zinc Oxide Films by Irradiation with Ultraviolet Lamp

Structural changes in sol-gel films with photo-irradiation were investigated using zinc oxide (ZnO) derived from zinc acetate. The exposure of the films to an ultraviolet lamp induced hexagonal ZnO crystals in a relatively dense amorphous structure. On the other hand, the formation of zinc metal was found in a porous gel film. The photo-induced crystallization and reduction are ascribed to the electronic excitation in the metastable non-crystalline states.     

Theoretical response to the discovery of deeply bound pionic states in208Pb(d,3He) reactions

Recently, deeply bound pionic states were found experimentally in (d,³He) reactions on²⁰⁸Pb. They found an isolated peak structure in the bound region below the pion production threshold. We study theoretically these excitation functions in (d,³He) reactions on²⁰⁸Pb at T _d =600 MeV. We found very good agreement with the (d,³He) excitation functions and could identify the underlying structures of the pionic states. We study the energy dependence of the (d,³He) reactions and the change of the excitation functions with the incident energy.     

Performance characteristics of narrow linewidth fiber laser pumped mid-IR difference frequency mixing light source for methane detection.

A high-power, narrow-linewidth Yb fiber laser with a fiber Bragg grating (FBG) pumped difference frequency generation (DFG) in a periodically poled lithium niobate (PPLN) crystal was investigated in detail. A mid-IR power of approximately 2.3 microW at 3.3 micrometers with a slope efficiency of 0.85 mW/W2 was achieved. A Doppler-broadened absorption spectrum of CH4 at 3038.497 cm-1 (3.2911 micrometers) was obtained with a 0.1-m long-gas cell at a pressure of 133 Pa. The linewidth of the DFG source was evaluated to be less than 96 MHz from the observed spectral linewidth. Real-time monitoring of CH4 (approximately 1.78 ppm) in ambient air in a multipass cell which has an optical path length of 10 m was also demonstrated.     

Nuclear properties far from the stability line in the relativistic mean field theory

We study the nuclear properties far from the stability line in the relativistic mean field theory. We find that the parameter set NL 1 provides very good results on binding energies of unstable nuclei, while NL2 results are not good, although both parameter sets give equally good results on nuclear properties for stable nuclei. We discuss the neutron number dependence of the proton and the neutron root mean square radii of proton magic nuclei.     

Phase Equilibrium in the System Ln-Mn-O IV. Ln=Sm at 1100°C

Phase equilibrium in a Sm-Mn-O system has been established at 1100°C while changing the oxygen partial pressure from 0 to 13.00 in −log (P_O2/atm), and a phase diagram at 1100°C is presented for a Sm₂O₃-MnO-MnO₂ system. Under the experimental conditions, Sm₂O₃, MnO, Mn₃O₄, SmMnO₃, and SmMn₂O₅ phases are present at 1100°C, but Sm₂MnO₄, Mn₂O₃, and MnO₂ are unstable in the system. LnMn₂O₅- type phase is stable under the present experimental conditions differing from the previously reported La-Mn-O and Nd-Mn-O systems.A wide range of nonstoichiometry has been found in the SmMnO₃ phase which coexisted with Sm₂O₃. X ranges from −0.010 at log P_O2=−10.00 to 0.098 at log P_O2=0 in the molecular formula of SmMnO_3+X. The nonstoichiometry is represented by an equation, N_O/N_SmMnO3=3.00×10⁻⁴ (log P_O2)³ +6.20×10⁻³ (log P_O2)²+4.28×10⁻² (log P_O2)+0.0979, and the activities of the components in the solid solution are calculated using the equation. SmMnO₃ seems to vary in composition in the Sm₂O₃-rich or Sm₂O₃-poor side as it was with LaMnO₃. SmMn₂O₅ is slightly nonstoichiometric.Lattice constants of SmMnO₃ made under different oxygen partial pressures and those of SmMn₂O₅ prepared in air were determined, along with spacings and relative intensities of SmMn₂O₅. Standard Gibbs energies of reactions shown in the system were calculated and compared with previously reported values.