Atomic Motion in Single H2_{2} and D2_{2} Molecule Junction Induced by Phonon Excitation

We have investigated Au atomic contacts in H$_{2}$ and D$_{2}$ environment by conductance measurement and $dI/dV$ spectroscopy. A single H$_{2}$ or D$_{2}$ molecule was found to bridge Au electrodes. In the case of the Au/H$_{2}$/Au junction, symmetric peaks were observed in $dI/dV$ spectra, while they were not observed for the Au/D$_{2}$/Au junction. The shape of the peaks in $dI/dV$ spectra originated from the structural change of the single molecule junction induced by the phonon excitation. The structural change could occur only for the Au/H$_{2}$/Au junction. The difference in the two single molecule junctions could be explained by larger zero point energy of Au-H$_{2}$ vibration mode than that in the Au/H$_{2}$/Au junction.Comment: 5 pages, 4 figures, to be appear in Phys. Rev.

Effect of polymer concentration on the lifetime and transmittance behavior of a self-oscillating polymer chain with a high lower critical solution temperature

In this study, we investigated the lifetime and self-oscillating behavior of a polymer chain with a high lower critical solution temperature (LCST). The polymer chain comprised 4-vinyl-4´-methyl-2,2´-bipyridinebis(2,2´-bipyridine)bis(hexafluorophosphate) ruthenium as catalyst for the Belousov–Zhabotinsky reaction and N-ethylacrylamide as the polymer main-chain with a high LCST when compared to N-isopropylacrylamide. We demonstrated that the self-oscillating behavior was significantly affected by the polymer concentration and measuring temperature. Moreover, we established that the lifetime of the transmittance self-oscillation can be predicted from the polymer concentration and measuring temperature

Effect of polymer concentration on the lifetime and transmittance behavior of a self-oscillating polymer chain with a high lower critical solution temperature

In this study, we investigated the lifetime and self-oscillating behavior of a polymer chain with a high lower critical solution temperature (LCST). The polymer chain comprised 4-vinyl-4´-methyl-2,2´-bipyridinebis(2,2´-bipyridine)bis(hexafluorophosphate) ruthenium as catalyst for the Belousov–Zhabotinsky reaction and N-ethylacrylamide as the polymer main-chain with a high LCST when compared to N-isopropylacrylamide. We demonstrated that the self-oscillating behavior was significantly affected by the polymer concentration and measuring temperature. Moreover, we established that the lifetime of the transmittance self-oscillation can be predicted from the polymer concentration and measuring temperature

Separation of Small DNAs by Gel Electrophoresis in a Fused Silica Capillary Coated with a Negatively Charged Copolymer

Active development of compact analytical instruments suitable for point-of-care testing (POCT) requires optimization of existing methods. To aid the development of capillary gel electrophoresis instruments for POCT, we attempted to separate polymerase chain reaction products (small DNAs) using a short, fused silica capillary coated with an acrylamide (AM)/acrylic acid (AA) copolymer (poly(AM-co-AA)). To realize the high capability of this capillary to separate small DNAs, the magnitude of electroosmotic flow (EOF) was controlled by varying the content of negatively charged AA in the copolymer, which significantly affected the separation ability. At an AA content ≥3.75 mol %, sample DNAs could not be injected into the copolymer-coated capillary owing to strong EOF, whereas a 100 bp DNA ladder sample was successfully separated at an AA content of ≤3.5 mol %, showing that even slight AA content variations impact DNA flow. EOF values measured using a neutral coumarin 334 solution suddenly decreased at an AA content of 3.5 mol % relative to those at an AA content of ≥3.75 mol %. Theoretical plate values revealed that an AA content of 2.75 mol % was optimal for separating ladder DNAs with sizes ≥600 bp. Hence, EOF control achieved by varying the amount of negatively charged AA in the poly(AM-co-AA) coating can promote further development of short capillaries for POCT applications

Influence of the Belousov–Zhabotinsky substrate concentration on the lifetime and self-oscillating behavior of a polymer solution

In this study, we synthesized a self-oscillating polymer chain with N-ethylacrylamide (NEAAm) as the main-chain. This exhibits a higher lower critical solution temperature than an N-isopropylacrylamide main chain. We subsequently measured the transmittance self-oscillation of poly[NEAAm-co-Ru(bpy)3] [Ru(bpy)3 = 4-vinyl-4’-methyl-2,2’-bipyridinebis(2,2’ bipyridine)bis(hexafluorophosphate) ruthenium] solutions comprising three Belousov-Zhabotinsky (BZ) substrates (malonic acid, sodium bromate, and sulfuric acid), under stirring at constant temperature. The soluble-insoluble self-oscillation of the polymer solution originated from the different solubility of the Ru(bpy)3 moiety as a catalyst of the BZ reaction in the reduced and oxidized states. We demonstrated that the self-oscillating behavior was significantly affected by the initial concentration of the sodium bromate. Moreover, we clarified that the lifetime of the transmittance self-oscillation can be predicted from the initial concentration of malonic acid

Influence of the Belousov–Zhabotinsky substrate concentration on the lifetime and self-oscillating behavior of a polymer solution

In this study, we synthesized a self-oscillating polymer chain with N-ethylacrylamide (NEAAm) as the main-chain. This exhibits a higher lower critical solution temperature than an N-isopropylacrylamide main chain. We subsequently measured the transmittance self-oscillation of poly[NEAAm-co-Ru(bpy)3] [Ru(bpy)3 = 4-vinyl-4’-methyl-2,2’-bipyridinebis(2,2’ bipyridine)bis(hexafluorophosphate) ruthenium] solutions comprising three Belousov-Zhabotinsky (BZ) substrates (malonic acid, sodium bromate, and sulfuric acid), under stirring at constant temperature. The soluble-insoluble self-oscillation of the polymer solution originated from the different solubility of the Ru(bpy)3 moiety as a catalyst of the BZ reaction in the reduced and oxidized states. We demonstrated that the self-oscillating behavior was significantly affected by the initial concentration of the sodium bromate. Moreover, we clarified that the lifetime of the transmittance self-oscillation can be predicted from the initial concentration of malonic acid