Broad-spectrum frequency comb generation and carrier-envelope offset frequency measurement by second-harmonic generation of a mode-locked fiber laser

A frequency comb spanning more than one octave has been achieved by injecting the second-harmonic generation (780 nm) of a mode-locked fiber laser (1.56 microm) into a photonic crystal fiber. We propose and realize a novel interferometric scheme for observing the carrier-envelope offset frequency of the frequency comb. Frequency noise has been observed on the measured carrier-envelope offset frequency, which has been confirmed to be generated in the photonic crystal fiber by comparing the measured beat frequencies between cw lasers and frequency combs before and after the photonic crystal fiber. The mode-locked fiber laser is considered to be an important candidate for the light source used in realizing a compact optical frequency measurement system including applications in the telecommunication bands.     

Charge transport in the insulating state of (DMe-DCNQI)2Li above T(SP): a possible fractional charge soliton conduction with +/-1 / 2e

A spin-Peierls system (DMe-DCNQI)2Li is studied with W-band electron paramagnetic resonance (EPR) ( approximately 94 GHz) to unveil a charge transport mechanism in the insulating 4k(F) charge density wave state above T(SP). The electron hopping between the neighbor DCNQI columns provides an additional broadening of the EPR linewidth, since the neighbor columns are generally nonequivalent to each other with respect to g shift. The obtained intercolumn hopping rates lead us to the conclusion that the electron hopping to a hole soliton carrying a fractional charge of e / 2 in the neighbor column dominates the intercolumn charge transport.     

The first Bianchi identity in synthetic differential geometry

We give a synthetic treatment of the first Bianchi identity both in the style of differential forms and in the style of tensor fields on the lines of Lavendhomme (Basic Concepts of Synthetic Differential Geometry, Kluwer, Dordrecht, 1996). The tensor-field version of the identity is derived from the corresponding one for microcubes, just as we did for the Jacobi identity of vector fields with respect to Lie brackets in our previous paper (J. Theoret. Phys. 36 (1997) 1099–1131). As a by-product we have found out an identity of microcubes corresponding to the classical identity

R(X,Y,Z)=_XYZ−_YXZ−_[X,Y]Z

of tensor fields, which has largely simplified Lavendhomme's lengthy proof (Basic Concepts of Synthetic Differential Geometry, Kluwer, Dordrecht, 1996, Section 5.3, Proposition 8, pp. 176–180).     

Supersmooth Topoi

It is well known that supersmooth functions are more akin to holomorphicfunctions than to smooth functions. The ultimate object of study in complexgeometry is not merely complex manifolds, but complex spaces, in whichholomorphic functions may be nilpotent and consequently invisible from ageometric viewpoint. Supergeometers have long been searching for an appropriatedefinition of supermanifold, for which many classical results in the theory ofsmooth manifolds can naturally be superized. However, they have not proceededfurther in quest of a supersmooth equivalent of complex space. The principalobject of this paper is to introduce the notion of supersmooth superspace intosupergeometry after the classical definition of complex space in complexgeometry, and then to build a good model of synthetic supergeometry after themanner of Dubuc and Taubin (1983), thereby superseding Yetter (1988). Themodel to be constructed is a Grothendieck topos encompassing the category ofG -supermanifolds and G -mappings as a full subcategory.     

Microscopically controlled oxidation of H/Si(1 0 0) by lateral surface electric field studied by emission electron microscopies

The ultrathin oxidation of a H/Si(1 0 0) surface with microfabricated pn-junctions was studied by photoemission electron microscopy (PEEM), mirror electron microscopy (MEM) and microscopic X-ray photoelectron spectroscopy (μ-XPS). The ultrathin oxidation inverts the contrast of the junctions in PEEM images. It is found by analyzing the intensity profiles of images that the potential distribution across the pn-junctions is also inverted by the oxidation. The charging of the oxide by ultraviolet irradiation from a light source of PEEM is attributed as the cause of the inversion of the contrast shown by μ-XPS and MEM.     

Continuous flame oxidation in supercritical water

Abstract

Continuous flames have been observed in Supercritical water oxidation (scWO) of isopropyl alcohol (IPA), using a vertical continuous reactor with sapphire windows and a mixing nozzle. Two types of continuous flame were confirmed: the one was long pale blue colored and the other was red short cone shaped, changing blue to red at around air ratio 2.0. The flame was strongly influenced by IPA concentration, air ratio and design of the mixing nozzle. Results for decomposition of PA are presented for IPA concentrations ranging from 600 up to 28260 ppm as TOC and initial reactor temperatures, were mostly around 490°C, at 25 MPa. Decomposition rate at steady state was over 99.9%. Experimentally measured CO₂ and O₂ concentrations at the flue gas were in good agreement with theoretically calculated values. Even for low air ratio as 1.1, high decomposition rate without CO, NO, NO₂ was achieved.     

Differential Forms in Synthetic Differential Supergeometry

We present a basic theory of differential formsin synthetic differential supergeometry. Exteriordifferential calculus is developed, and Cartan's threemagic formulas as well as a variant of de Rham's theorem are established.     

Deracemization of 1,2-diol monotosylate derivatives by a combination of enzymatic hydrolysis with the Mitsunobu inversion using polymer-bound triphenylphosphine

The deracemization of 1,2-diol monotosylate derivatives is achieved by the sequential combination of enzymatic hydrolysis and Mitsunobu inversion using a polymer-bound triphenylphosphine. After the lipase-catalysed hydrolysis of the racemic 2-acetoxyhexyl tosylate, the subsequent Mitsunobu reaction without separation causes an inversion of the resulting (R)-alcohol to give the (S)-enantiomer of the acetate as a single product. In particular, the reaction using the polymer-bound triphenylphosphine also proceeds smoothly, and the product is easily separated by filtration from the polymer-bound reagent and its by-products. This deracemization process is applicable to the preparation of several optically active 1,2-diol monotosylates.