Dynamic control of gold nanoparticle morphology in a microchannel flow reactor by glucose reduction in aqueous sodium hydroxide solution

Continuous flow synthesis of gold nanoparticles was demonstrated using a microchannel reactor with glucose reduction in aqueous alkaline medium. Particle size, morphology, and visual/optical properties of the dispersion liquid were controlled dynamically by tuning of the rate of NaOH addition. Characteristic star-like nanoparticles formed spontaneously as a quasi-stable state, but they changed the morphology to round shape and showed spectral change over time.     

Magnetic-force-induced long-period fiber gratings

A novel formation method of a long-period fiber grating (LPFG) based on a magnetic-force-induced microbend is proposed and experimentally demonstrated. The LPFG employs a permanent magnet that exerts transversal force to the fiber by attracting a steel coil spring. The transversal force causes periodic microbending to the fiber, and therefore the transmission wave attenuates at the core-to-cladding mode resonance. This device has advantages of ease of fabrication, reconfigurability, and available for any type of fiber.     

Properties of gallium- and aluminum-doped bulk ZnO obtained from single-crystals grown by liquid phase epitaxy

Bulk properties of gallium (Ga)- and aluminum (Al)-doped zinc oxide (ZnO) were studied using bulky single-crystalline thick films grown by liquid phase epitaxy (LPE). The highest possible dopant concentration was 1×10¹⁹ cm^–3 for LPE growth at around 800 °C. The electron concentration was nearly same to the Ga and Al concentrations. The donor binding energy decreased to nearly zero with an increase in dopant concentration, and electron mobility of the sample with relatively high dopant concentration (1×10¹⁹ cm^–3) was more than 60 cm² V^–1 s^–1 at room temperature. The LPE technique is a potential solution for the production of ZnO for optical applications because the well-defined excitonic luminescence could be seen from the LPE-grown-doped single-crystals.     

Consistency of the intensional level of the Minimalist Foundation with Church’s thesis and axiom of choice

Consistency with the formal Church’s thesis, for short CT, and the axiom of choice, for short AC, was one of the requirements asked to be satisfied by the intensional level of a two-level foundation for constructive mathematics as proposed by Maietti and Sambin (in Crosilla, Schuster (eds) From sets and types to topology and analysis: practicable foundations for constructive mathematics, Oxford University Press, Oxford, 2005). Here we show that this is the case for the intensional level of the two-level Minimalist Foundation, for short MF, completed in 2009 by the second author. The intensional level of MF consists of an intensional type theory à la Martin-Löf, called mTT. The consistency of mTT with CT and AC is obtained by showing the consistency with the formal Church’s thesis of a fragment of intensional Martin-Löf’s type theory, called \(\mathbf{MLtt}_1\), where mTT can be easily interpreted. Then to show the consistency of \(\mathbf{MLtt}_1\) with CT we interpret it within Feferman’s predicative theory of non-iterative fixpoints \(\widehat{ID_1}\) by extending the well known Kleene’s realizability semantics of intuitionistic arithmetics so that CT is trivially validated. More in detail the fragment \(\mathbf{MLtt}_1\) we interpret consists of first order intensional Martin-Löf’s type theory with one universe and with explicit substitution rules in place of usual equality rules preserving type constructors (hence without the so called \(\xi \)-rule which is not valid in our realizability semantics). A key difficulty encountered in our interpretation was to use the right interpretation of lambda abstraction in the applicative structure of natural numbers in order to model all the equality rules of \(\mathbf{MLtt}_1\) correctly. In particular the universe of \(\mathbf{MLtt}_1\) is modelled by means of \(\widehat{ID_1}\)-fixpoints following a technique due first to Aczel and used by Feferman and Beeson.     

Gas-phase chlorine-initiated photooxidation of methanol and isopropanol

The photolysis of CH₃OH/Cl₂/air, CH₃OH/Cl₂/NO₂/air, and (CH₃)₂CHOH/Cl₂/NO₂/air at 28 ± 2°C was studied using the long-path FTIR method. The primary reactions of methanol and isopropanol with Cl atoms were α-hydrogen abstraction (100%), and α hydrogen (85%), and α-hydrogen abstraction (15%), respectively. The failure to detect hydroxyalkyl-peroxy nitrates suggested that the oxygen addition to α-hydroxy radicals is not important. From the product distribution an upper limit of the ratio of oxygen addition to CH₂OH and CH₃CHOH was estimated to be about 6 and 7%, respectively. The oxygen addition ratio to (CH₃)₂COH was very low. The reaction mechanism is also discussed.     

Stereochemistry of the base-catalyzed methanolysis of 2-phenyl-tetrahydropyrrolo-1,3,2-oxazaphospholes

Diastereomerically pure bicyclic oxazaphospholes were prepared from L-prolinol and phenylphosphonic or thiophosphonic dichloride and their absolute configurations were determined based on the interpretation of NMR spectra. The base-catalyzed methanolysis of those compounds was found to proceed by exclusive PO bond cleavage with complete inversion of configuration.     

Effects of Hf and W doping on the commensurate charge density waves in 1T-TaS2

The electrical resistivities of Hf-doped and W-doped 1T-TaS₂ have been measured to investigate the influence of varying the Fermi level on the formation of commensurate charge density waves. It was found that W-doping is far more effective in breaking the C-CDW phase than Hf-doping. Such results are explained by the energy consideration of the system with the Hubbard gap which is produced by the Mott-localization.     

Ternary liquid—liquid equilibria: The associated solution theory

The capabilities of the associated solution theory in correlating ternary liquid—liquid phase equilibria from binary data have been examined. It is shown that the theory is capable of quantitatively good correlation of data for the four systems studied.     

Semi-empirical molecular orbital calculations the electronic structure and the spin-orbit coupling in azabenzenes

Electronic structures of pyridine, pyrazine, pyrimidine and pyridazine are studied by a semiempirical SCF method for valence electron systems previously proposed by the present authors. The charge distributions, transition energies and oscillator strengths of these compounds are calculated. The calculated results show fairly good agreement with the observed ones. Using these results, we have further calculated the oscillator strengths of singlet-triplet transitions and the life times of the triplet states (). In this treatment, we have considered the mixing of various singlets with T ₁ and triplets with S ₀, and the effect of -electrons is studied.

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Zusammenfassung Es werden nach einer von den Autoren dieser Arbeit vorgeschlagenen Methode die Elektronenstrukturen von Pyridin, Pyrazin, Pyrimidin und Pyridazin studiert. Die halbempirische SCF-Methode für Valenzelektronensysteme gestattet die Berechnung der Ladungsverteilungen, Übergangsenergien und Oszillatorstärken, die in recht guter Übereinstimmung mit der Beobachtung stehen. Ferner werden die Oszillatorstärken von Singulett-Triplett-Übergängen und die Lebensdauer von Triplett-Zuständen () berechnet.

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Résumé Les structures électroniques de la pyridine, de la pyrazine, de la pyrimidine et de la pyridazine sont étudiées par une méthode SCF semiempirique pour les électrons de valence proposée précédemment par les auteurs. Les distributions de charge, les énergies de transition et les forces oscillatrices de ces composés sont calculées, donnant des résultats en bon accord avec l'expérience. De plus nous avons calculé les forces oscillatrices des transitions singulet-triplet et les durées de vie des états triplets (). Dans ce calcul nous avons inclus l'interaction de configuration et l'étude de l'effet des électrons .

     

Locating subsets of a Hilbert space

This paper deals with locatedness of convex subsets in inner product and Hilbert spaces which plays a crucial role in the constructive validity of many important theorems of analysis.