Showing papers by "Toyota published in 2007"

Crystallization and Melting Behavior of Poly (l-lactic Acid)

Abstract: Effects of the crystallization temperature on the crystal structure and its melting behavior of poly (l-lactic acid) (PLLA) have been investigated by means of wide-angle (WAXS) and small-angle (SAXS) X-ray scattering, optical microscopy, and differential scanning calorimetory (DSC). PLLA was found to crystallize as the α form when the crystallization temperature Tc was higher than 120 °C, while significant change in lattice parameters was seen for Tc's below 120 °C. The ratio of the a- and b-axis lengths begins to decrease with Tc below 120 °C and is 31/2 below 90 °C, which suggests a new crystalline form with hexagonal packing, namely, the α‘ form. The possible reason for α‘ formation is discussed. High-temperature WAXS and SAXS measurements showed that α‘ crystal transforms into ordered a form during heating. The transition takes place at 150 °C without a decrease in scattering intensity and without heating rate dependence. The mechanism for the transition is discussed.

Fructose/dioxygen biofuel cell based on direct electron transfer-type bioelectrocatalysis

Abstract: One-compartment biofuel cells without separators have been constructed, in which d-fructose dehydrogenase (FDH) from Gluconobacter sp. and laccase from Trametes sp. (TsLAC) work as catalysts of direct electron transfer (DET)-type bioelectrocatalysis in the two-electron oxidation of d-fructose and four-electron reduction of dioxygen as fuels, respectively. FDH adsorbs strongly and stably on Ketjen black (KB) particles that have been modified on carbon papers (CP) and produces the catalytic current with the maximum density of about 4 mA cm(-2) without mediators at pH 5. The catalytic wave of the d-fructose oxidation is controlled by the enzyme kinetics. The location and the shape of the catalytic waves suggest strongly that the electron is directly transferred to the KB particles from the heme c site in FDH, of which the formal potential has been determined to be 39 mV vs. Ag|AgCl|sat. KCl. Electrochemistry of three kinds of multi-copper oxidases has also been investigated and TsLAC has been selected as the best one of the DET-type bioelectrocatalyst for the four-electron reduction of dioxygen in view of the thermodynamics and kinetics at pH 5. In the DET-type bioelectrocatalysis, the electron from electrodes seems to be transferred to the type I copper site of multi-copper oxidases. TsLAC adsorbed on carbon aerogel (CG) particles with an average pore size of 22 nm, that have been modified on CP electrodes, produces the catalytic reduction current of dioxygen with a density of about 4 mA cm(-2), which is governed by the mass transfer of the dissolved dioxygen. The FDH-adsorbed KB-modified CP electrodes and the TsLAC-adsorbed CG-modified CP electrodes have been combined to construct one-compartment biofuel cells without separators. The open-circuit voltage was 790 mV. The maximum current density of 2.8 mA cm(-2) and the maximum power density of 850 microW cm(-2) have been achieved at 410 mV of the cell voltage under stirring.

Driver Modeling Based on Driving Behavior and Its Evaluation in Driver Identification

Abstract: All drivers have habits behind the wheel. Different drivers vary in how they hit the gas and brake pedals, how they turn the steering wheel, and how much following distance they keep to follow a vehicle safely and comfortably. In this paper, we model such driving behaviors as car-following and pedal operation patterns. The relationship between following distance and velocity mapped into a two-dimensional space is modeled for each driver with an optimal velocity model approximated by a nonlinear function or with a statistical method of a Gaussian mixture model (GMM). Pedal operation patterns are also modeled with GMMs that represent the distributions of raw pedal operation signals or spectral features extracted through spectral analysis of the raw pedal operation signals. The driver models are evaluated in driver identification experiments using driving signals collected in a driving simulator and in a real vehicle. Experimental results show that the driver model based on the spectral features of pedal operation signals efficiently models driver individual differences and achieves an identification rate of 76.8% for a field test with 276 drivers, resulting in a relative error reduction of 55% over driver models that use raw pedal operation signals without spectral analysis

Friction behavior of high-density poly(2-methacryloyloxyethyl phosphorylcholine) brush in aqueous media

Abstract: Super-hydrophilic polymer brushes were prepared by surface-initiated atom transfer radical polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) on initiator-immobilized silicon wafers. The graft density was estimated to be ca. 0.22 chains nm−2 based on the linear relationship between Mn and the layer thickness. The contact angle against water was very low, and air bubbles in water hardly attached onto the brush surface, indicating a super-hydrophilic surface. Neutron reflectivity measurements of the poly(MPC) brush showed that the grafting polymer chains extended a fair amount in the vertical direction from the substrate in a good solvent such as water, while they shrunk in a poor solvent. Frictional properties of the poly(MPC) brushes were characterized by sliding a glass ball probe in air and various solvents under a load of 0.49 N at a sliding velocity of 90 mm min−1. An extremely low friction coefficient of the poly(MPC) brush was observed in humid atmosphere because water molecules adsorbed into the brush layer acted as a lubricant.

Nitrogen complex species and its chemical nature in TiO2 for visible-light sensitized photocatalysis

Abstract: A photocatalyst with high reactivity under visible-light has been desired to utilize solar irradiation or interior lighting efficiently Nitrogen-doped TiO2 revealed significant improvement in optical absorption and photocatalytic activity over TiO2 under visible light We have performed the first-principles calculations to study the detailed N complex species introduced in TiO2 The results include stable geometries, densities of states, formation energies, and core levels The present systematic studies account for the long-term controversial issue on N-doped TiO2, in particular, regarding the detailed assignment of N 1s binding energies observed in the XPS measurement The detailed analyses of the formation energies show that introducing the N species more in a controlled way via process conditions is crucial to achieve the optimized photocatalytic performance

Tracking as Repeated Figure/Ground Segmentation

Abstract: Tracking over a long period of time is challenging as the appearance, shape and scale of the object in question may vary. We propose a paradigm of tracking by repeatedly segmenting figure from background. Accurate spatial support obtained in segmentation provides rich information about the track and enables reliable tracking of non-rigid objects without drifting. Figure/ground segmentation operates sequentially in each frame by utilizing both static image cues and temporal coherence cues, which include an appearance model of brightness (or color) and a spatial model propagating figure/ground masks through low-level region correspondence. A superpixel-based conditional random field linearly combines cues and loopy belief propagation is used to estimate marginal posteriors of figure vs background. We demonstrate our approach on long sequences of sports video, including figure skating and football.

Spark ignition type internal combustion engine

Abstract: In a spark ignition type internal combustion engine that includes a variable compression ratio mechanism A capable of changing the mechanical compression ratio, and a variable valve mechanism B capable of changing valve characteristics of an intake valve or an exhaust valve, the variable valve mechanism is mechanically coupled to the variable compression ratio mechanism, and the variable valve mechanism is controlled in accordance with the compression ratio-changing operation amount of the variable compression ratio mechanism. The variable valve mechanism is coupled to the variable compression ratio mechanism without intervention of an electronic control unit. Therefore, the possibility of the interference between a piston and an intake valve resulting from an abnormality in a control system that includes an electronic control unit as an intervening unit can be eliminated.

"Ideal" engineering alloys.

Abstract: A newly discovered group of alloys, called Gum Metals, approaches ideal strength in bulk form, exhibits significant plastic deformation prior to failure, and shows no indications of conventional-dislocation activity. Two conditions must be met for a material to exhibit this "ideal" behavior: (1) the stress required to trigger conventional-dislocation plasticity in the material must exceed its ideal strength, and (2) the material must be intrinsically ductile when stressed to ideal strength. Gum Metals satisfy both criteria, explaining their remarkable mechanical properties.

Relation between electrical conductivity and chemical stability of BaCeO3-based proton conductors with different trivalent dopants

Abstract: Trivalent-cation-doped BaCeO 3 has fairly high protonic conductivity at intermediate temperatures. This paper deals with the effects of the kind of dopant, M in BaCe 0.9 M 0.1 O 3-α (M = Y, Tm, Yb, Lu, In, or Sc), on the electrical (ionic) conductivity at 400-900°C and chemical stability. It was found that the two properties are both governed by the ionic radii of the dopants and are in a trade-off relation. The electrical conductivity seems to be also affected by the electronegativity of the dopant element, i.e., the conductivity increases with increasing ionic radius and decreasing electronegativity (increasing basicity).

A Vertical Insulated Gate AlGaN/GaN Heterojunction Field-Effect Transistor

Abstract: We fabricated a vertical insulated gate AlGaN/GaN heterojunction field-effect transistor (HFET), using a free-standing GaN substrate. This HFET has apertures through which the electron current vertically flows. These apertures were formed by dry etching the p-GaN layer below the gate electrodes and regrowing n--GaN layer without mask. The HFET exhibited a specific on-resistance of as low as 2.6 mΩ·cm2 with a threshold voltage of -16 V. This HFET would be a prototype of a GaN-based high-power switching device.

Vehicle and control method of vehicle

Abstract: In the vehicle of the invention, when the driver releases a depressed accelerator pedal, the drive control sets a vehicle speed V at the moment to a target vehicle speed V* (step S440). An engine and a motor for outputting driving power are controlled to drive the vehicle at the target vehicle speed V*. When the driver steps on a released brake pedal, the drive control stores the target vehicle speed V* set before the driver's depression of the brake pedal as a previous target vehicle speed Vpre and cancels the setting of the target vehicle speed V* (steps S470 and S480). In response to the driver's subsequent release of the brake pedal, the drive control sets the vehicle speed V at the moment to the target vehicle speed V* (step S510) and restarts constant-speed drive (cruise drive). When the driver turns a steering wheel to or over a preset degree for a left turn or a right turn, the drive control sets the previous target vehicle speed Vpre to the target vehicle speed V* (step S520) and restarts the constant-speed drive. This arrangement ensures easy and quick start of the constant-speed drive (cruise drive) and enables the constant-speed drive (cruise drive) according to the variation of the driving state.

Robust interest point detector and descriptor

Abstract: Methods and apparatus for operating on images are described, in particular methods and apparatus for interest point detection and/or description working under different scales and with different rotations, e.g. for scale- invariant and rotation-invariant interest point detection and/or description. The present invention can provide improved or alternative apparatus and methods for matching interest points either in the same image or in a different image. The present invention can provide alternative or improved software for implementing any of the methods of the invention. The present invention can provide alternative or improved data structures created by multiple filtering operations to generate a plurality of filtered images as well as data structures for storing the filtered images themselves, e.g. as stored in memory or transmitted through a network. The present invention can provide alternative or improved data structures including descriptors of interest points in images, e.g. as stored in memory or transmitted through a network as well as datastructures associating such descriptors with an original copy of the image or an image derived therefrom, e.g. a thumbnail image.

Catalyst for purification of exhaust gas

Abstract: Provided is a technique by which excellent exhaust gas purification performances can be achieved. The exhaust gas-purifying catalyst according to the present invention includes a substrate, a first catalytic layer facing the substrate and comprising at least one precious metal selected from the group consisting of palladium and platinum, and alumina doped with an alkaline-earth metal element, and a second catalytic layer facing the substrate with the first catalytic layer interposed therebetween or intervening between the substrate and the first catalytic layer, the second catalytic layer comprising rhodium and alumina doped with the alkaline-earth metal element.

Modeling and Recognition of Driving Behavior Based on Stochastic Switched ARX Model

Abstract: This paper presents the development of the modeling and recognition of human driving behavior based on a stochastic switched autoregressive exogenous (SS-ARX) model. First, a parameter estimation algorithm for the SS-ARX model with multiple measured input-output sequences is developed based on the expectation-maximization algorithm. This can be achieved by extending the parameter estimation technique for the conventional hidden Markov model. Second, the developed parameter estimation algorithm is applied to driving data with the focus being on driver's collision avoidance behavior. The driving data were collected using a driving simulator based on the cave automatic virtual environment, which is a stereoscopic immersive virtual reality system. Then, the parameter set for each driver is obtained, and certain driving characteristics are identified from the viewpoint of switched control mechanism. Finally, the performance of the SS-ARX model as a behavior recognizer is examined. The results show that the SS-ARX model holds remarkable potential to function as a behavior recognizer.

Dynamic recovery and recrystallization in titanium alloys by hot deformation

Abstract: The microstructural change of β titanium alloys, Ti-15V-3Cr-3Sn-3Al and Ti-10V-2Fe-3Al, and an (α+β) titanium alloy, Ti-6Al-4V, during hot deformation at temperatures in β single-phase and (α+β) two-phase regions was studied. For the β titanium alloys, dynamic recovery takes place dominantly within β grains during deformation in the β single-phase region although some discontinuous dynamic recrystallization occurs along β grain boundaries. The size and fraction of recrystallized β grains increase as strain rate decreases or the deformation temperature rises.

The Communication Complexity of Correlation

Abstract: We examine the communication required for generating random variables remotely. One party Alice is given a distribution D, and she has to send a message to Bob, who is then required to generate a value with distribution exactly D. Alice and Bob are allowed to share random bits generated without the knowledge of D. There are two settings based on how the distribution D provided to Alice is chosen. If D is itself chosen randomly from some set (the set and distribution are known in advance) and we wish to minimize the expected communication in order for Alice to generate a value y, with distribution D, then we characterize the communication required in terms of the mutual information between the input to Alice and the output Bob is required to generate. If D is chosen from a set of distributions D, and we wish to devise a protocol so that the expected communication (the randomness comes from the shared random string and Alice's coin tosses) is small for each D isin D, then we characterize the communication required in this case in terms of the channel capacity associated with the set D. Our proofs are based on an improved rejection sampling procedure that relates the relative entropy between two distributions to the communication complexity of generating one distribution from the other. As an application of these results, we derive a direct sum theorem in communication complexity that substantially improves the previous such result shown by Jain et al. (2003).

Power supply system.

Abstract: A controller executes local generation and local consumption pathways of: supplying power from a solar cell to an appliance, and charging a storage cell with power that remains after subtracting power consumed by the appliance from the solar cell power. In the absence of excess power, the storage cell and solar cell supply power. Power supply from a commercial electrical grid covers a power shortage that remains after subtracting solar cell power and storage cell power from the power consumed by the appliance. The controller also executes a second excess power selling mode pathway wherein excess power flows into the commercial electrical grid, and an assist mode wherein all solar cell power flows into the commercial electrical grid, and storage cell power flows to the appliance.

Variable compression ratio internal combustion engine

Abstract: A variable compression ratio internal combustion engine rotates a camshaft to cause relative movement between a crankcase and a cylinder block. The camshaft has a shaft member, a cam member fixed to the shaft member, and a movable bearing member rotatable with respect to the shaft member. The cam member is rotatably housed in a cam housing hole formed in the crankcase, and the movable bearing member is rotatably housed a bearing housing hole formed in the cylinder block. The length of a line segment joining the centers of the shaft member and the movable bearing member, the center of the movable bearing member being the center of rotation of the movable bearing member with respect to the bearing housing hole, is set to be longer than the length of a line segment joining the centers of the shaft member and the cam member, the center of the cam member being the center of rotation of the cam member with respect to the cam housing hole.

Parking assist apparatus and method

Abstract: The present invention is aimed at setting an efficient target track of a vehicle and thus improving convenience of the parking assist. According to the present invention, a parking assisting apparatus for assisting parking a vehicle is provided. The parking assisting apparatus comprises detecting means for detecting a positional relationship between an obstacle near the vehicle and a parking section line painted on the ground. The parking assisting apparatus is configured to vary a target track of the vehicle toward a target parking position based on the detected positional relationship between the obstacle and the parking section line.

Parking assistance device and parking assistance method

Abstract: A parking assisting device includes an ambient area detecting unit that detects an obstacle or a parking frame in an ambient area surrounding a vehicle, and a guiding unit guides the vehicle to a parking initial position from which parking of the vehicle to a parking space, adjacent to the detected obstacle, or the detected parking frame is permissible. In the parking assisting device, a guidance mode in which the guiding unit guides the vehicle to the parking initial position is set up based on a distance between the vehicle and the detected obstacle or the detected parking frame in a vehicle width direction of the vehicle.

Exhaust gas purifying catalyst

Abstract: According to the present invention, an exhaust gas purifying catalyst is provided. The catalyst comprises a porous silica support comprising silica having a pore structure, and a perovskite-type composite metal oxide particle supported in the pore structure of the porous silica support. Further, the peak attributable to the space between silica primary particles is in the range of 3 to 100 nm in the pore distribution of the porous silica support.

Equation of motion for coarse-grained simulation based on microscopic description

Abstract: We have derived an equation of motion for coarse-grained particles by using a projection operator. Because the derived coarse-grained equation is based on microscopic description, it can be the basis for models of various coarse-grained simulations. We show that by substitution of random forces into fluctuating forces in the coarse-grained equation, the equations for Brownian dynamics and dissipative particle dynamics are reproduced.