For biosensors with host specificity for influenza viruses, we used sugar chains with different coordinations of terminal sialic acid and penultimate galactose. Sialylglycopeptide (SGP) is one of the candidates for detecting molecules in the biosensors for influenza viruses, and we have investigated the host specificity of the viruses using an enzyme-linked immunosorbent assay (ELISA). Using the bovine serum albumin (BSA) localization, we have obtained the stable distribution. The clustering of sugar chains could also enhance and stabilize the binding activity. Comparing with single sugar chains of SGP, clusterized molecules of SGP-BSA showed the reduction of relative errors in the fluctuation in binding activity.
J-PARC 3 GeV rapid cycling synchrotron (RCS) is one of the highest beam power proton accelerators, which accelerates 8.3×1013 protons at 25 Hz up to 3 GeV, corresponding 1 MW beam power. Challenges for achieving an ultrahigh vacuum (UHV) region in the beam line come from the large static and dynamic outgassing. In the RCS vacuum system, turbomolecular pump was taken up as main pump because it can evacuate such continuous and additional outgassing with a large pumping speed in the wide pressure range. Turbomolecular pump also has the advantage of not causing pressure instabilities like ion pumps. The more than 10 years operation of the RCS vacuum system showed that the UHV was rapidly obtained from the atmospheric pressure or low vacuum. It was also shown that the large additional outgassing during the degassing of the kicker magnets or high-power beam operation was promptly evacuated by the turbomolecular pump due to its constant pumping speed in the wide pressure rage. Free-run touchdown, which is a typical trouble of the turbomolecular pumps, was resolved by the developments of both elongation of cables between pump and controller and improvement of the touchdown bearing. As the developments in anticipation of the future requirement for the extreme high vacuum region, the developments, which are the combination with NEG and a development of a turbomolecular pump with the rotor of titanium alloy, are undergoing.
The divide-and-conquer type density functional tight-binding molecular dynamics (DC-DFTB-MD) is a useful method to simulate chemical reactions of large systems. The present study applied the method to surface reaction, namely, proton diffusion process between H2O and OH on Pt(111) surface. The proton diffusion coefficients for systems with different surface coverage, ratio of adsorbed molecules, and temperature were estimated. The calculated results showed that the proton diffusion process in six-membered ring hydrogen bond network is an order of magnitude slower than that in no-six-membered ring structures. Furthermore, we confirmed the elevation of temperature from typical experimental condition of 130 K leads to more frequent proton transfer events and larger proton diffusion coefficients, while the magnitude of increasing trend varies between with and without the six-membered ring structure. The present study indicated that the proton diffusion process strongly depends on the local structure of H2O and OH layer at Pt(111) surface.
We fabricated metastable palladium hydride by hydrogen ion implantation to a 10 nm-thick Pd film at 7 K, and monitored the hydride formation and relaxation to a stable state by resistivity measurements. By heating the sample, we observed a substantial change in resistivity below 100 K without accompanying hydrogen desorption. While the resistivity change was observed at 80 K for both H and D, it was observed only for H at 6 K. This irreversible resistivity change is attributed to transition from the metastable state to its stable state by hydrogen diffusion. It is considered that hydrogen atoms undergo diffusion thermally at 80 K and by quantum tunneling at 6 K.
In the thin-film growth of organic semiconductors, understanding the elementary processes is required to control thin-film structures such as molecular orientation and nucleation density. We have used the quartz crystal microbalance (QCM), which is non-destructive and high-sensitivity measurement technique, for the in-situ analysis of initial stage in organic thin-film growth. In this study, we evaluate the initial stage in thin-film growth of pentacene, which is a bench mark material in the organic semiconductors, on a polyimide surface, and discuss the nucleation process considering a meta-stable state.
In order to estimate the threshold of photoelectron yield spectroscopy (PYS), regression estimator was created by machine learning using calculation data based on Fowler's theory. We compared verification data with the prediction by regression estimators. The verification data measured by AC-3 instrument manufactured by Riken Keiki Co. are the number of 87 (Au : 31, Metals except for Au : 16, oxide · semiconductor : 15, organic : 25) with estimate value by analyst (label data). As a result, the prediction performance was 70% over in the range of difference between label data and estimation from ±0.2 eV. On the other hand, spectra in the difference of 0.3 eV were included in difficult labeling by analysts. The prediction by machine learning gives the guide to analysis.
The submicron MoS2 surface becomes soft, which weakens the atomic bonding at the surface and reduces the friction. We can find superlubricity with a friction force of piconewtons at the nanostructures of a submicron, even though power is not supplied from the outside. The superlubricity described here is a novel type of superlubricity involving surface softening, is easily achievable and very simple, because it uses only nanostructures smaller than a micron.
Scanning probe electrospray ionization (SPESI) enables the ambient sampling and ionization of molecules in a solid material by utilizing charged nano-volume liquid with a capillary probe. In order to understand the dynamic change of charged nano-volume liquid at the end of capillary probe, the probe displacement and the mass spectra during a single sampling and ionization process were measured simultaneously. It was found that the dynamic behavior of liquid bridge was affected by the physical properties of solvents. The time to break a liquid bridge was positively correlated with the surface tension of solvent while the time from the breakage of liquid bridge to the detection of sample ions was positively correlated with the viscosity of solvent.