Time filter

Source Type

Wang X.,Waseda University | Ishii Y.,Waseda University | Ruslinda A.R.,Waseda University | Hasegawa M.,Japan Advanced Institute of Industrial Technology | Kawarada H.,Waseda University
ACS Applied Materials and Interfaces | Year: 2012

An aptasensor was designed on a nanocrystalline diamond (NCD) surface that combined with biological recognition elements, PDGF-binding aptamers, which inherently possess high affinity to PDGF-BB proteins. Functional components such as carboxylic acids (-COOH) and amines (-NH 2) were directly introduced onto the NCD surface and used as probing units for immobilization of PDGF-binding aptamers. The surface coverage of different components on the NCD was analyzed by X-ray photoelectron spectroscopy (XPS) measurements, and the effects of various functionalizations on the NCD biosensor performance were investigated via fluorescence observations. The coverages of carboxyl and amine groups achieved were 12 and 23%, respectively, for the directly aminated and carboxylated NCD; however, the lower density of carboxyl groups on the functionalized surface did not deteriorate the performance of the COOH-NCD biosensor. Fluorescence investigations demonstrated comparable performance in sensitivity and selectivity for PDGF protein detection on COOH-NCD and NH 2-NCD biosensors. Multiple regeneration tests clearly showed that the COOH-NCD biosensor as well as the NH 2-NCD biosensor retained a high performance without exhibiting any noticeable degradation. © 2012 American Chemical Society.

Kawai H.,Kanazawa Institute of Technology | Murao T.,Japan Advanced Institute of Industrial Technology | Fujita M.,Tokyo Institute of Technology
Journal of Intelligent and Robotic Systems: Theory and Applications | Year: 2011

This paper considers the vision-based estimation and pose control with a panoramic camera via passivity approach. First, a hyperbolic projection of a panoramic camera is presented. Next, using standard body-attached coordinate frames (the world frame, mirror frame, camera frame and object frame), we represent the body velocity of the relative rigid body motion (position and orientation). After that, we propose a visual motion observer to estimate the relative rigid body motion from the measured camera data. We show that the estimation error system with a panoramic camera has the passivity which allows us to prove stability in the sense of Lyapunov. The visual motion error system which consists of the estimation error system and the pose control error system preserves the passivity. After that, stability and L 2-gain performance analysis for the closed-loop system are discussed via Lyapunov method and dissipative systems theory, respectively. Finally, simulation and experimental results are shown in order to confirm the proposed method. © 2011 Springer Science+Business Media B.V.

Yoneya M.,Japan Advanced Institute of Industrial Technology | Kawasaki M.,Hitachi Ltd. | Ando M.,Hitachi Ltd.
Journal of Physical Chemistry C | Year: 2012

Molecular dynamics simulations were performed for mono- and multilayer pentacene films on a simple model surface to study polymorphs of the deposition-processed thin-films. The layer-by-layer deposition history was taken into account by successive layer-stacking simulations of monolayer, bilayer and up to five-layered systems. We found that the tilt-free monolayer polymorph and the molecular tilting upon stacking layers on this monolayer were realized in the simulations even without any substrate interactions. These results imply that neither the monolayer nor the small angle tilted thin-film polymorph is substrate-induced as commonly explained. Our results also show a crucial dependence on the layer stacking history for the thin-film polymorph, which indicate that the thin-film polymorph would be induced with the layering history starting from the tilt-free monolayer. © 2011 American Chemical Society.

Nishizawa O.,Japan Advanced Institute of Industrial Technology | Kanagawa K.,Chiba University
Geophysical Journal International | Year: 2010

Seismic velocity anisotropy of biotite schist (30 per cent-mode biotite) was measured under confining pressures up to 150 MPa. The rock shows weak orthotropy which was altered from transverse isotropy (TI) generated by biotite-preferred orientation. The orthotropy was caused by microfolding in the rock. The velocity increase under confining pressure indicates that most crack planes are aligned parallel to the cleavage planes (silicate sheet) of the oriented biotite minerals. The anisotropy of the rock is basically TI due to both the aligned biotite minerals and cracks, which have a common symmetry axis. We found that other sheet silicate-rich rocks have a similar anisotropy with the biotite schist, in which the TI-type anisotropy is characterized by the slow P- and S-wave velocities along the symmetry axis. This is caused by the preferred orientation of sheet silicate minerals and the extremely slow P- and S-wave velocities along the axis perpendicular to the silicate sheet compared to the directions along the silicate sheet. When rock contains a large percentage of highly oriented sheet silicates, the fast and slow shear waves exchange their polarities at some off-symmetry axis directions, indicating that the qS-wave (quasi-S wave) velocity exceeds the SH-wave velocity. The phase velocity distribution of qS wave shows an asymmetry with respect to the angle from the symmetry axis, which is characterized by a bulge in this distribution located near the symmetric axis. This is inherent to most sheet silicate minerals. When crack density of aligned cracks increases, the P-wave velocity along the symmetry axis decreases considerably. The qS-wave phase velocity in the off-axis directions also decreases, in accordance with the decrease of the P velocity along the symmetry axis. The asymmetry of the qS-wave phase velocity distribution increases as the P-wave velocity decreases along the symmetry axis. This relationship can be well understood by means of Berryman's extended Thomsen approach. © 2010 The Authors Journal compilation © 2010 RAS.

Kurumida J.,Japan Advanced Institute of Industrial Technology | Yoo S.J.B.,University of California at Davis
IEEE Journal on Selected Topics in Quantum Electronics | Year: 2012

This paper discusses nonlinear optical signal processing employed in optical packet switching systems. Nonlinear optical signal processing provides optical label (header) recognition, optical switching, wavelength conversion, and time buffering with typically higher capacity, lower latency, and lower power consumption than electronic counterparts. In order to provide diverse signal processing functions, large-scale integration of nonlinear optical signal processing devices is essential. We discuss possible future directions in optical packet switching involving nonlinear optical signal processing of optical packets with advanced data and label modulation formats. © 2011 IEEE.

Discover hidden collaborations