Immobilization of glucose oxidase on carbon paper electrodes modified with conducting polymer and its application to a glucose fuel cell

A carbon paper electrode was modified with the conducting copolymer of 3-methylthiopene and thiophene-3-acetic acid prepared electrochemically on the electrode, and an enzyme electrode was fabricated by covalent immobilization of glucose oxidase on the modified electrode. The modification with the conducting copolymer increased the surface area of the electrode and the amount of the immobilized enzyme. As a result, the enzyme electrode showed a high catalytic activity. Moreover, it was found that the increased surface area led to a high rate of electron transfer reaction between the electrode and p-benzoquinone employed as an electron mediator. The enzyme electrode fabricated with the modified carbon paper gave a larger glucose oxidation current than that fabricated with the bare one. In addition, the glucose oxidation current was found to increase with increasing content of the conducting copolymer in the modified carbon paper. Corresponding to the large glucose oxidation current, high performance was confirmed for the glucose fuel cell constructed with the enzyme electrode based on the modified carbon paper.     

Trudinger’s Inequality for Double Phase Functionals with Variable Exponents

Czechoslovak Mathematical Journal - Our aim in this paper is to establish Trudinger’s inequality on Musielak-Orlicz-Morrey spaces LΦ,κ(G) under conditions on Φ which are...     

Spectral and temporal optical signal generation using randomly distributed quantum dots

Optical Review - Quantum dots (QDs) have a great potential for realizing information processing because of their signal-modulation capability based on energy transfer. We present a method for...     

Sobolev's inequality for Riesz potentials of functions in Morrey spaces of integral form

Morrey spaces have become a good tool for the study of existence and regularity of solutions of partial differential equations. Our aim in this paper is to give Sobolev's inequality for Riesz potentials of functions in Morrey spaces (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A remark on Nesterenko’s theorem for Ramanujan functions

We study the algebraic independence of values of the Ramanujan q-series $A_{2j+1}(q)=\sum_{n=1}^{\infty}n^{2j+1}q^{2n}/(1-q^{2n})$ or S _2j+1(q) (j≥0). It is proved that, for any distinct positive integers i, j satisfying $(i,j)\not=(1,3)$ and for any $q\in \overline{ \mathbb{Q}}$ with 0<|q|<1, the numbers A ₁(q), A _2i+1(q), A _2j+1(q) are algebraically independent over $\overline{ \mathbb{Q}}$ . Furthermore, the q-series A _2i+1(q) and A _2j+1(q) are algebraically dependent over $\overline{ \mathbb{Q}}(q)$ if and only if (i,j)=(1,3).     

Algebraic relations for reciprocal sums of odd terms in Fibonacci numbers

In this paper, we prove the algebraic independence of the reciprocal sums of odd terms in Fibonacci numbers ∑ _n=1^∞ F _2n−1⁻¹, ∑ _n=1^∞ F _2n−1⁻², ∑ _n=1^∞ F _2n−1⁻³ and write each ∑ _n=1^∞ F _2n−1^−s (s≥4) as an explicit rational function of these three numbers over ℚ. Similar results are obtained for various series including the reciprocal sums of odd terms in Lucas numbers.      

InxGa1−xAs/GaAs quantum wire structures grown on GaAs (100) patterned substrates with [001] ridges

In_xGa_1−xAs/GaAs (x = 0.12-0.23) quantum well (QW) structures were grown by molecular beam epitaxy (MBE) on [001] ridges with various widths (1.1-12 μm) of patterned GaAs (100) substrate. The smallest lateral width of the InGaAs/GaAs quantum wire (QWR) structures was estimated to be about 0.1 μm by high-resolution scanning electron microscope (SEM). The In contents of the grown InGaAs/GaAs QWs on the ridges were studied as a function of ridge top width (ridge width of the MBE grown layer) by cathodoluminescence (CL) measurements at 78 K. Compared to the InGaAs QW grown on a flat substrate, the In content of the InGaAs/GaAs QW on the ridge increases from 0.22 to 0.23 when the ridge top width decreases to about 2.9 μm, but it decreases steeply from 0.23 down to 0.12 with a further decrease of the ridge width from 2.9 to 0.05 μm. A simulation of MBE growth of InGaAs on the [001] ridges shows that this reduced In content for narrow ridges is due to a large migration of Ga atoms to the (100) ridge top region from {110} side facets.     

Extremely flat interfaces in GaAs/AlGaAs quantum wells with high Al content(0.7) grown on GaAs (411)A substrates by molecular beam epitaxy

Effectively atomically flat interfaces over a macroscopic area (200 μm diameter) have been achieved in GaAs/Al_0.7Ga_0.3As quantum wells (QWs) with well widths of 3.6-12 nm grown on (411)A GaAs substrates by molecular beam epitaxy (MBE) for the first time. A single and very narrow photoluminescence peak (FWHM, full width at half maximum, is 6.1 meV) was observed at 717.4 nm for the QW with a well width of 3.6 nm at 4.2 K. The linewidth is comparable to that of growth-interrupted QWs grown on (100)-oriented GaAs substrates by MBE. A 1.5 μm thick Al_0.7Ga_0.3As layer with good surface morphology also could be grown on (411)A GaAs substrates in the entire growth temperature region of 580-700°C, while rough surfaces were observed in Al_0.7Ga_0.3As layers simultaneously grown on (100) GaAs substrates at 640-700°C. These results indicate that the surface of GaAs and Al_0.7Ga_0.3As grown on the (411)A GaAs substrates are extremely flat and stable on the (411)A plane.