Dispersions of image potential states on surfaces of clean graphite and lead phthalocyanine film

Dispersions of image potential states on a graphite surface (denoted IPS1) and on 1 monolayer (ML) film (denoted IPS2) of lead phthalocyanine (PbPc) are investigated by the micro-spot angle-resolved two-photon photoemission (micro-AR-2PPE) spectroscopy. On the graphite surface, whole dispersions of the two members of IPS1 (n = 1 and 2) are observed. The n = 1 IPS1 peak is weakly visible at energy higher than the vacuum level. The effective mass of an electron in the n = 1 IPS1 becomes slightly light at the high momentum region, suggesting the interaction between the IPS1 and the unoccupied σ-band of graphite. On the PbPc film, the IPS2 band forms a band gap and back-folds at the boundary of the Brillouin zone. A 1-dimensional Kronig-Penny model is used to reproduce the effective mass and the shift of binding energy.     

Hf(IV)-catalyzed enantioselective epoxidation of N-alkenyl sulfonamides and N-tosyl imines

Asymmetric epoxidation of allylic and homoallylic amine derivatives catalyzed by Hf(IV)-bishydroxamic acid complexes is described. Under similar conditions, aldimine and ketimine produced oxaziridines. The sulfonyl group is demonstrated to be an effective directing group for these transformations.     

Microchip electrophoresis of oligosaccharides using lectin-immobilized preconcentrator gels fabricated by in situ photopolymerization

A lectin-impregnated gel was fabricated at the channel crossing point in a microfluidic chip made from polymethyl methacrylate (PMMA). The acrylamide containing lectin was photopolymerized to form a round gel (radius 60 μm) by irradiation with an argon laser, which was also used for fluorometric detection. This gel was applied to specific concentration, elution, and electrophoretic separation of fluorescent-labeled oligosaccharides. Because the lectin in the polyacrylamide gel was mechanically immobilized, it maintained its activity. The lectin was used to trap up to a few tens of femtomoles of specific oligosaccharides labeled with 8-aminopyrene-1,3,6-trisulfonic acid with 2 min by a factor >800, and the amount trapped corresponded to ca. 70% of lectin in the gel. The trapped oligosaccharides were released from the gel by lowering the pH with an acidic background electrolyte. The oligosaccharides that eluted as a broad band were concentrated by transient isotachophoresis stacking using concentrated sodium borate buffer (pH 11.0). The stacked sample components were then separated and fluorometrically detected at the end of the separation channel. Under the optimized conditions, resolution of the saccharides was good, and was similar to that obtained by pinched injection. The method was applied to preconcentration and analysis of oligosaccharides derived from some glycoproteins.     

Conformity and precision of CO2 densimetry in CO2 inclusions: microthermometry versus Raman microspectroscopic densimetry

To assess the ability of densimetry for CO₂ fluid in CO₂ inclusions, we compare two methods, microthermometry and Raman microspectroscopic densimetry for CO₂. The comparative experiment was performed for nine CO₂ inclusions in three mantle xenoliths. The results are as follows: (1) microthermometry precisely determines CO₂ density with the range of 0.65 to 1.18 g/cm³ compared with Raman microspectroscopic densimetry; (2) CO₂ density obtained by Raman microspectroscopic densimetry is fairly consistent with that by microthermometry; (3) it is hard to determine CO₂ density in CO₂ inclusion with diameter of less than around 3 µm using microthermometry; and (4) microthermometry can be applied only to the CO₂ inclusion whose CO₂ density ranges from around 0.65 to 1.18 g/cm³, whereas the Raman microspectroscopic densimetry is applicable to CO₂ density ranging from 0.1 to 1.24 g/cm³. The above features carry the potential for estimation of depth origin of mantle‐derived rocks. The depth where the rocks were trapped by host magma can be estimated using both geothermometric data and CO₂ fluid density in CO₂ inclusions in the rocks. Typical precisions of density of CO₂ in CO₂ inclusions obtained by the Raman microspectroscopic densimetry (~0.01 g/cm³) and by the microthermometry (< 0.001 g/cm³) correspond to uncertainties in the depth origin of 2.4 km and < 1.7 km, respectively, at 1000 ± 50 °C. In case of the mantle under 750–1250 °C and 1 GPa, the CO₂ fluid has a density ranging from 1.06 g/cm³ to 1.21 g/cm³, which are well measured by the Raman microspectroscopic densimetry. Combination of both densimetries for CO₂ in mantle minerals elucidates the deep structure of the Earth. Copyright © 2012 John Wiley & Sons, Ltd.     

Precise determination of Mg/Fe ratios applicable to terrestrial olivine samples using Raman spectroscopy

The relationship between Mg# [ = 100 Mg/(Mg + Fe) in mol] and the Raman shift was analyzed precisely for olivine [(Mg, Fe)₂SiO₄] samples with Mg# between 100 and 62.8. Two prominent peaks at 826–820 cm⁻¹ (peak 1) and 858–849 cm⁻¹ (peak 2) and three subordinate peaks at 883–881 cm⁻¹ (peak 3), 920–914 cm⁻¹ (peak 4), and 967–951 cm⁻¹ (peak 5) were observed to shift monotonously to lower wavenumbers with decreasing Mg#. The ΔMg#( = Mg#_ref − Mg#) versus Δν(= ν_ref − ν) can be linearly regressed for each peak as ΔMg# = A Δν, where ν is a peak wavenumber of olivine with Mg# ranging from 100 to 62.8, and ν_ref is that of olivine with a reference value of Mg#, namely, Mg#_ref. We set Mg#_ref as 100 (i.e.pure forsterite Mg₂SiO₄) whereas A is a regression parameter (5.789, 4.294, 12.34, 6.348, and 2.09, respectively,for peaks 1, 2, 3, 4, and 5). This equation enables us to avoid small inter‐laboratory differences of wavenumber calibration. The equation for peak 2 yields estimations of Mg# in geologically satisfactory precision, ± 1 Mg# (1σ) in the Mg# range of 100–62.8. Copyright © 2011 John Wiley & Sons, Ltd.     

An order-N electronic structure theory with generalized eigenvalue equations and its application to a ten-million-atom system

A linear algebraic theory called the 'multiple Arnoldi method' is presented and realizes large-scale (order-N) electronic structure calculations with generalized eigenvalue equations. A set of linear equations, in the form of (zS - H)x = b, are solved simultaneously with multiple Krylov subspaces. The method is implemented in a simulation package ELSES (www.elses.jp) with tight-binding-form Hamiltonians. A finite-temperature molecular dynamics simulation is carried out for metallic and insulating materials. A calculation with 10(7) atoms was realized by a workstation. The parallel efficiency is shown up to 1024 CPU cores.     

Control of single molecular nanodot patterns of phenyl azomethine dendrimers by statistical simulation

Precisely synthesized subnanometer particles of metals or metal oxides can be prepared using dendritic polyphenyl azomethines as the template. With a goal of their arrays to a surface using a simple and quick process, such as spin-casting, statistical analyses were applied to a nanodot array of the dendrimers to obtain the relationship between the experimental condition and the results such as size, spacing, or its standard deviations. The dot patterns of a single molecular dendrimer on a substrate were able to be predicted with numerical values of the experimental parameters associated with the spin coat (concentration of the dendrimer, physical properties of solvent, the spin coating recipe, temperature of the solution, relative humidity (RH)) as the inputs for the statistical analysis.     

Release behavior of capsules loaded by volatile liquid in multicores

The vapor release behavior of capsules containing volatile liquids in multicores was derived theoretically and compared with experimental data. The time course of the release amount was expressed by the same polynomial functional form as that for capsules having a single core, neglecting the interaction between the releases from different cores. Alginate capsules containing tea tree oil in multicores prepared by the insolubilization reaction were used for vapor release experiment. The time course of the release amount was well expressed by the polynomial equation suggested by the theory. From the parameters determined by fitting of the data to the theoretical equations, the activation energy for permeation of vapor through the wall membrane was estimated.     

Optical path-length matrix method for estimating skin spectrum

In this article, we propose a new method??the optical path-length matrix method (OPLM)??as a faster alternative to the Monte Carlo for multi-layered media (MCML), which is often used to simulate the skin spectrum. Theoretically, peripheral oxygen saturation can be estimated by iterating MCML, but it is not a realistic strategy because it requires huge computation time. The optical path-length matrix is obtained as the probabilistic density histograms of the optical path length in skin using MCML, and once the matrix is obtained, skin spectral reflectance can be calculated by accumulating all combinations of elements in the matrix and by setting an absorption coefficient based on the Beer-Lambert law. The computational time of OPLM was approximately 26,000 times faster than that of MCML.