Effect of Mn on Aging of (Pb0.63Ba0.37)(Zr0.7Ti0.3)O3 Dielectric Ceramics

An aging model for relaxors is suggested on the basis of the transformation of a supercooled cubic lattice into a tetragonal lattice. Manganese ions distort the crystal lattice, and the distortion affects the phase transformation rate. As a result, the aging rate may be expected to change. The lattice constant of (Pb_0.63Ba_0.37)(Zr_0.7Ti_0.3)O₃+χ MnO mol% dielectric ceramics was used as a measure of the degree of the distortion. As the lattice constant decreased up to 0.5 MnO mol%, the aging rate increased, justifying the proposed model.     

Fundamental investigation of subsurface damage in single crystalline silicon caused by diamond machining

Single crystalline silicon was plunge-cut using diamond tools at a low speed. Cross-sectional transmission electron microscopy and laser micro-Raman spectroscopy were used to examine the subsurface structure of the machined sample. The results showed that the thickness of the machining-induced amorphous layer strongly depends on the tool rake angle and depth of cut, and fluctuates synchronously with surface waviness. Dislocation activity was observed below the amorphous layers in all instances, where the dislocation density depended on the cutting conditions. The machining pressure was estimated from the micro-cutting forces, and a subsurface damage model was proposed by considering the phase transformation and dislocation behavior of silicon under high-pressure conditions.     

Naturally inspired SERS substrates fabricated by photocatalytically depositing silver nanoparticles on cicada wings

Densely stacked Ag nanoparticles with an average diameter of 199 nm were effectively deposited on TiO₂-coated cicada wings (Ag/TiO₂-coated wings) from a water-ethanol solution of AgNO₃ using ultraviolet light irradiation at room temperature. It was seen that the surfaces of bare cicada wings contained nanopillar array structures. In the optical absorption spectra of the Ag/TiO₂-coated wings, the absorption peak due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles was observed at 440 nm. Strong Surface-enhanced Raman scattering (SERS) signals of Rhodamine 6G adsorbed on the Ag/TiO₂-coated wings were clearly observed using the 514.5-nm line of an Ar⁺ laser. The Ag/TiO₂-coated wings can be a promising candidate for naturally inspired SERS substrates.     

Field experiments on energy consumption and thermal comfort in the office environment controlled by occupants’ requirements from PC terminal

The thermal environment in an office is not always optimal from the viewpoint of energy-conservation and occupants’ comfort. The main reason is that air-conditioning systems are controlled without taking the occupants’ needs into account. In this study, we would like to propose a new system to control air-conditioning systems, lighting systems, etc. via occupants’ requests. This system collects occupants’ requests from their own personal computers and controls the air-conditioning system with logic that balances the needs of occupants and energy consumption. The control logic is referred to as “Logic for Building a Consensus” and can be adjusted according to operating strategies such as energy-saving or occupants’ satisfaction with their environment. Moreover, the variety of feedback motivates occupants to cooperate with energy-saving efforts.

An interactive system to use occupants’ requests for controlling the air-conditioning system and providing a variety of feedback was developed. A series of cooling experiments were conducted in an open-plan office where about 50 people worked. The results show that this interactive system could save 20% more energy compared with controlling an air-conditioning system at a constant 26 °C.     

Reconstruction of B-spline skinning surface from generalized cylinder mesh

We propose a novel method to reconstruct B-spline surfaces from generalized cylindrical meshes by skinning. Skinning is a well known surface creation technique and has been used in CAD and CG modeling. However, there are few papers which address the issue of automated creation and preparation of sectional curves for skinning. Although our method is only applicable to generalized cylindrical meshes, there are many real world objects which can be created or reconstructed by skinning. The proposed surface reconstruction method is fully automated with minimal user interventions. We have evaluated the validity of this method by reconstructing B-spline surfaces from various polygonal meshes varying in shapes and geometries. The final results show the effectiveness of our proposed method.     

A 3.7 MHz phased array probe using 0.91Pb(Zn(1/3)Nb(2/3))O(3)-0.09PbTiO(3 )

A novel 128-channel phased array probe for echocardiography with a center frequency of 3.7 MHz using 0.91Pb(Zn(1/3)Nb(2/3))O(3)-0.09PbTiO(3 ) (PZN-9%PT) single crystal has been fabricated to realize greater sensitivity and broader bandwidth properties. The echo amplitude of the PZN-9%PT single-crystal probe is about 5 dB higher than that of the conventional lead airconate titanate (PZT) ceramic probe, and the fractional bandwidth is about 25 percentage points broader. The quality of B mode images obtained by the PZN-9%PT probe satisfies the performance of the two types of conventional PZT ceramic probes that have center frequencies of 2.5 and 3.75 MHz. At the reference frequency of 3 MHz, the Doppler sensitivity of the PZN-9%PT probe is about 5 dB higher than that of the 3.75 MHz PZT probe; the blood flow of a pulmonary vein in a hard-to-image patient is much more clearly imaged than in the case of using the PZT probe. These superior images are attributable to the use of sufficiently large PZN-9%PT single crystals obtained by the self-flux method.     

Step by step filter based program for calculations of highly informative derivative curves

We have developed a microcomputer program, based on a recently described approach called step by step filter (SBSF), for calculation of derivative curves directly from spectra recorded as a function of wavelength. This program avoids the long wavelength attenuation featured at conventional method for derivative curves calculation, and in this extent could be very helpful for daily spectroscopy practice. The features of the SBSF program include: easy treatment of data through a windowed environment, calculating of both conventional and step by step filter derivatives, possibilities for selection of the mathematical conditions for smoothing and differentiation simultaneous plotting of the original curve and its derivative and a mouse pointer. Several examples from different branches of the molecular spectroscopy (absorption UV-VIS, CD and fluorescence) are provided and discussed in the terms of advantages of SBSF.     

Effects of first- and third-person perspectives created using a head-mounted display on dart-throwing accuracy

Virtual Reality - The first-person perspective (1PP) and third-person perspective (3PP) have both been adopted in video games. The 1PP can induce a strong sense of immersion, and the 3PP allows...     

Modeling development process of skill-based system for human-like manipulation robot

The importance of system integration is widely recognized in robotics. This motivates the application of Model-Based Systems Engineering (MBSE) approaches to improve the development process of robot systems. This paper models a development process to achieve given task goals using a human-like upper body robot based on MBSE approach. For this purpose, we focus on the domain knowledge of tasks and skills in robotics. Since MBSE is a general methodology, there is a lot of flexibility on the way of proceeding with the analysis and design, and how to utilize models there. Using the concept of tasks and skills is helpful for better uderstanding of the development process. Our process is based on three main concepts: (1) stakeholders of User and Developer, (2) coordination between User and Developer using skills as communication interface, (3) extension development. Making the process explicit helps many stakeholders such as robot makers, system integrators, and engineers in various application domains to join the system development. It is also effective for accumulating experiences and work products of the development. In addition, we can expect that better understanding of the engineering process results in the improvement of the process performed by automation tools and humans cooperatively.     

Nondominated coteries on graphs

Let C and D be two distinct coteries under the vertex set V of a graph G=(V,E) that models a distributed system. Coterie C is said to G-dominate D (with respect to G) if the following condition holds: For any connected subgraph H of G that contains a quorum in D (as a subset of its vertex set), there exists a connected subgraph H' of H that contains a quorum in C. A coterie C on a graph G is said to be G-nondominated (G-ND) (with respect to G) if no coterie D(≠C) on G G-dominates C. Intuitively, a G-ND coterie consists of irreducible quorums. This paper characterizes G-ND coteries in graph theoretical terms, and presents a procedure for deciding whether or not a given coterie C is G-ND with respect to a given graph G, based on this characterization. We then improve the time complexity of the decision procedure, provided that the given coterie C is nondominated in the sense of Garcia-Molina and Barbara (1985). Finally, we characterize the class of graphs G on which the majority coterie is G-ND