Showing papers by "Toyota published in 2004"

Functional porous coordination polymers.

Abstract: The chemistry of the coordination polymers has in recent years advanced extensively, affording various architectures, which are constructed from a variety of molecular building blocks with different interactions between them. The next challenge is the chemical and physical functionalization of these architectures, through the porous properties of the frameworks. This review concentrates on three aspects of coordination polymers: 1). the use of crystal engineering to construct porous frameworks from connectors and linkers ("nanospace engineering"), 2). characterizing and cataloging the porous properties by functions for storage, exchange, separation, etc., and 3). the next generation of porous functions based on dynamic crystal transformations caused by guest molecules or physical stimuli. Our aim is to present the state of the art chemistry and physics of and in the micropores of porous coordination polymers.

Lead-free piezoceramics

Abstract: Lead has recently been expelled from many commercial applications and materials (for example, from solder, glass and pottery glaze) owing to concerns regarding its toxicity. Lead zirconium titanate (PZT) ceramics are high-performance piezoelectric materials, which are widely used in sensors, actuators and other electronic devices; they contain more than 60 weight per cent lead. Although there has been a concerted effort to develop lead-free piezoelectric ceramics, no effective alternative to PZT has yet been found. Here we report a lead-free piezoelectric ceramic with an electric-field-induced strain comparable to typical actuator-grade PZT. We achieved this through the combination of the discovery of a morphotropic phase boundary in an alkaline niobate-based perovskite solid solution, and the development of a processing route leading to highly textured polycrystals. The ceramic exhibits a piezoelectric constant d33 (the induced charge per unit force applied in the same direction) of above 300 picocoulombs per newton (pC N(-1)), and texturing the material leads to a peak d33 of 416 pC N(-1). The textured material also exhibits temperature-independent field-induced strain characteristics.

Funktionale poröse Koordinationspolymere

Abstract: Die Chemie der Koordinationspolymere hat sich in den vergangenen Jahren rasant entwickelt. Strukturen aus einer Vielzahl molekularer Bausteine mit unterschiedlichen Wechselwirkungen sind mittlerweile zuganglich. Die nachste Stufe ist die chemische und physikalische Funktionalisierung dieser Architekturen durch Einstellung ihrer Porositaten. Dieser Aufsatz konzentriert sich auf drei Aspekte von Koordinationspolymeren: 1) Anwendung von Kristall-Engineering zum Aufbau poroser Geruste aus Konnektoren und Linkern (“Nanospace-Engineering”), 2) Charakterisierung und Katalogisierung poros-struktureller Funktionalitat fur Anwendungen in Speicherungs-, Austausch-, Trennprozessen etc. und 3) poros-strukturelle Funktionalitat auf der Basis dynamischer Kristallumwandlungen durch Gastmolekule oder physikalische Reize. Ziel ist es, den aktuellen Stand der Forschung zur Chemie und Physik von und in den Mikroporen poroser Koordinationspolymere vorzustellen.

Ultrahigh-quality silicon carbide single crystals

Abstract: Silicon carbide (SiC) has a range of useful physical, mechanical and electronic properties that make it a promising material for next-generation electronic devices. Careful consideration of the thermal conditions in which SiC [0001] is grown has resulted in improvements in crystal diameter and quality: the quantity of macroscopic defects such as hollow core dislocations (micropipes), inclusions, small-angle boundaries and long-range lattice warp has been reduced. But some macroscopic defects (about 1-10 cm(-2)) and a large density of elementary dislocations (approximately 10(4) cm(-2)), such as edge, basal plane and screw dislocations, remain within the crystal, and have so far prevented the realization of high-efficiency, reliable electronic devices in SiC (refs 12-16). Here we report a method, inspired by the dislocation structure of SiC grown perpendicular to the c-axis (a-face growth), to reduce the number of dislocations in SiC single crystals by two to three orders of magnitude, rendering them virtually dislocation-free. These substrates will promote the development of high-power SiC devices and reduce energy losses of the resulting electrical systems.

First-principles calculations for development of low elastic modulus Ti alloys

Abstract: The elastic constants of the ${\mathrm{Ti}}_{1\ensuremath{-}x}{X}_{x}$ ($X=\mathrm{V}$, Nb, Ta, Mo, and W) and ${\mathrm{Zr}}_{1\ensuremath{-}x}{X}_{x}$ ($X=\mathrm{Nb}$ and Mo) binary alloys were calculated for $x=0.0$, 0.25, 0.5, 0.75, and 1.0 by the ultrasoft pseudopotential method within the generalized gradient approximation to density functional theory to clarify the mechanisms by which the low elastic moduli of the Ti binary alloys are realized. The Young's moduli of the polycrystals for these Ti or Zr binary alloys were calculated from the calculated elastic constants of the single crystal by using the Voigt-Reuss-Hill averaging scheme. The results show that the Young's moduli of the $\mathrm{Ti}\text{\ensuremath{-}}X$ or $\mathrm{Zr}\text{\ensuremath{-}}X$ binary alloys have the minimum values in the vicinity of $x=0.25$. From the calculation results, we have found that ${C}_{11}\ensuremath{-}{C}_{12}$ is correlated with the valence electron number per atom and the value of ${C}_{11}\ensuremath{-}{C}_{12}$ becomes nearly zero with the valence electron number of around 4.20--4.24. ${C}_{11}\ensuremath{-}{C}_{12}$ also represents the stability of the bcc structure in these alloys and we thus emphasize that controlling the valence electron number at around 4.20--4.24 is important to realize a low-Young's-modulus material in the Ti or Zr binary alloys having bcc structure.

Method and system for speech recognition using grammar weighted based upon location information

Abstract: A speech recognition method and system for use in a vehicle navigation system utilize grammar weighted based upon geographical information regarding the locations corresponding to the tokens in the grammars and/or the location of the vehicle for which the vehicle navigation system is used, in order to enhance the performance of speech recognition. The geographical information includes the distances between the vehicle location and the locations corresponding to the tokens, as well as the size, population, and popularity of the locations corresponding to the tokens.

Development of new-generation hybrid system THS II - Drastic improvement of power performance and fuel economy

Abstract: Toyota Hybrid System (THS), the powertrain that combines a gasoline engine and an electric motor was first introduced in December 1997. It became the first mass-produced hybrid passenger vehicle in the world, gaining a reputation as a highly innovative vehicle, and its cumulative worldwide sales have exceeded 120,000 units. In 2003, THS had a further evolution. The new-generation Toyota Hybrid System (THS II) would be introduced on the new Prius. This report shall explain THS II, which achieved drastic improvements in power performance and fuel economy, while securing the most stringent emission standard Advanced Technology Partial Zero Emission Vehicle (ATPZEV).

First-principles study on lithium borohydride Li B H 4

Abstract: First-principles calculations have been performed on lithium borohydride $\mathrm{Li}\mathrm{B}{\mathrm{H}}_{4}$ using the ultrasoft pseudopotential method, which is a potential candidate for hydrogen storage materials due to its extremely large gravimetric capacity of $18\phantom{\rule{03em}{0ex}}\text{mass}\phantom{\rule{03em}{0ex}}%$ hydrogen We focus on an orthorhombic phase observed at ambient conditions and predict its fundamental properties; the structural properties, electronic properties, dielectric properties, vibrational properties, and the heat of formation The calculation gives a nearly ideal tetrahedral shape for $\mathrm{B}{\mathrm{H}}_{4}$ complexes, although the recent experiment suggests that their configuration is strongly distorted [J-Ph Souli\'e et al, J Alloys Compd 346, 200 (2002)] Analyses for the electronic structure and the Born effective charge tensors indicate that Li atoms are ionized as ${\mathrm{Li}}^{+}$ cations The internal bonding of ${[\mathrm{B}{\mathrm{H}}_{4}]}^{\ensuremath{-}}$ anions is primarily covalent The high-frequency dielectric permittivity tensor ${\ensuremath{\epsilon}}_{\ensuremath{\infty}}$ is predicted as almost isotropic, but the static dielectric permittivity tensor ${\ensuremath{\epsilon}}_{0}$ as considerably anisotropic The $\mathrm{\ensuremath{\Gamma}}$-phonon eigenmodes can be classified into three groups, namely, the librational modes involving the displacements of ${\mathrm{Li}}^{+}$ cations (less than $500\phantom{\rule{03em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$), and the internal B-H bending and stretching modes of ${[\mathrm{B}{\mathrm{H}}_{4}]}^{\ensuremath{-}}$ anions (around 1100 and $2300\phantom{\rule{03em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$, respectively) The molecular approximation fairly reproduces the phonon frequencies in the latter two groups, implying the strong internal bonding of $\mathrm{B}{\mathrm{H}}_{4}$ complexes The librational modes have significant contributions to the large anisotropies of ${\ensuremath{\epsilon}}_{0}$ The agreement of the heat of formation with the experimental value is reasonably good

Spermidine Synthase Genes Are Essential for Survival of Arabidopsis

Abstract: The cellular polyamines putrescine, spermidine, and spermine are ubiquitous in nature and have been implicated in a wide range of growth and developmental processes. There is little information, however, on mutant plants or animals defective in the synthesis of polyamines. The Arabidopsis genome has two genes encoding spermidine synthase, SPDS1 and SPDS2. In this paper, we describe T-DNA insertion mutants of both of these genes. While each mutant allele shows normal growth, spds1-1 spds2-1 double-mutant seeds are abnormally shrunken and they have embryos that are arrested morphologically at the heart-torpedo transition stage. These seeds contain significantly reduced levels of spermidine and high levels of its precursor, putrescine. The embryo lethal phenotype of spds1-1 spds2-1 is complemented by the wild-type SPDS1 gene. In addition, we observed a nearly identical seed phenotype among an F2 seed population from the cross between the spds2-1 allele and SPDS1 RNA interference transgenic lines. These data provide the first genetic evidence indicating a critical role of the spermidine synthase in plant embryo development.

Rational design and crystal structure determination of a 3-D metal-organic jungle-gym-like open framework.

Abstract: A new three-dimensional (3-D) jungle-gym-like open metal-organic framework has been synthesized from a two-dimensional (2-D) layer compound using a heterogeneous pillar insertion reaction. Both the starting 2-D layer and the resulting 3-D open compounds have been characterized using X-ray crystallography.

The discovery of polymer-clay hybrids

Abstract: The first successful example of a polymer-clay hybrid was nylon-clay hybrid (NCH), which is a nano-meter-sized composite of nylon-6 and 1-nm-thick exfoliated aluminosilicate layers of the clay mineral. NCH was found and developed at Toyota Central Research and Development Laboratories over 17 years ago. The NCH containing a few weight percentages of clay exhibits superior properties such as high modulus, high strength, and good gas-barrier properties. The key for the discovery of NCH was the polymerization of a nylon monomer in the interlayer space of the clay. This highlight presents the development of NCH from its discovery to its commercialization. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 819–824, 2004

Synthesis of mono-dispersed mesoporous silica spheres with highly ordered hexagonal regularity using conventional alkyltrimethylammonium halide as a surfactant

Abstract: Mono-dispersed mesoporous silica spheres with highly ordered hexagonal regularity were obtained with tetramethoxysilane (TMOS)–alkyltrimethylammonium chloride–methanol–water–sodium hydroxide. Just by changing the methanol ratio in the solvent, mono-dispersed particles were obtained with C14TMACl, C16TMACl and C18TMACl as surfactants under the same reactant concentrations. The adsorption properties of the samples were specific surface areas of 1150–1200 m2 g−1 and pore volumes of 0.60–0.81 cm3 g−1. Work is underway to explore new potential applications of these materials which possess both mono-dispersion characteristics and ordered mesoporous regularity with various mean pore sizes and particle diameters.

NOx Storage-Reduction Catalysts for Gasoline Engines

Abstract: The automotive catalyst technology is now faced with very difficult problems. As the result of automakers' efforts to produce more efficient and lower-emission vehicles, lean-burn gasoline engines have been introduced into the market. While these engines are much more efficient than conventional ones, NOx removal has become significantly more difficult. After enormous efforts, we succeeded in solving the problem, by inventing a new class of catalyst. We overcame two strict problems with the new type catalyst, which are sulfur poisoning and thermal deterioration.

Parking assist apparatus and parking assist method for vehicle

Abstract: Parking assist apparatus and method cause a vehicle driver to set a target parking position in which the vehicle is to be parked by prompting the driver to specify the position of a parking space frame in the screen of a touch display by touch-operating arrow button switches shown in the screen, and then calculate a path to the target parking position. If a path to the target parking position is not generated by calculation, the arrow button switches for moving the parking space frame in such directions that a path will not be generated (i.e., the vehicle cannot be parked), among all the arrow button switches, are made non-displayed or are displayed dimmer than the other arrow button switches, and are disabled.

Amorphous carbon, amorphous-carbon coated member, and process for forming amorphous carbon film

Abstract: To provide a soft amorphous carbon exhibiting a low elastic modulus, an amorphous-carbon coated member provided with a coated film comprising the amorphous carbon, and a process for forming an amorphous carbon film The amorphous carbon comprises carbon as a major component and hydrogen in an amount of from more than 30 atomic % to 60 atomic % or less, and exhibits an elastic modulus of from 40 or more to 150 GPa or less Moreover, the amorphous-carbon coated member comprises a conductive substrate, and a coated film fixed on at least a part of a surface of the substrate and composed of the amorphous carbon In addition, in a process for forming the amorphous-carbon coated film, an amorphous carbon film is formed on a surface of conductive substrates by a plasma CVD method Not only a plurality of the substrates are disposed on a substrate holder, which is disposed in a film-forming furnace and is connected with a negative electrode, in such a state that they face to each other, but also a processing gas pressure and a plasma power source are operated so as to overlap negative glows of the neighboring two substrates

Variable valve system

Abstract: A variable valve mechanism is installed to change the operating angle and lift amount of an intake valve in accordance with the rotation position of a control shaft. A worm wheel is secured to the control shaft. The worm wheel is coupled to a motor actuator via a worm gear. The motor actuator is controlled during a normal operation so that the rotation position of the control shaft changes within a normal rotation range. A low-end stopper and high-end stopper are installed outside the normal rotation range to mechanically restrict the rotation of the control shaft.

Nitride semiconductor device

Abstract: Disclosed is a nitride semiconductor light-emitting device composed of a silicon substrate (1), a main semiconductor region (3) arranged thereon and having a light-emitting function, and a p-type semiconductor layer (8) arranged on the main semiconductor region (3) The main semiconductor region (3) is composed of an n-type semiconductor layer (6), an active layer (7) and a p-type semiconductor layer (8) A light-transmitting electrode (10) is composed of an Ag alloy An additive element is mixed in the Ag alloy for the light-transmitting electrode (10) for suppressing oxidation or sulfuration The Ag alloy mixed with the additive element is high in stability and excellent in light transmittance and ohmic properties

The automotive application of discontinuously reinforced TiB-Ti composites

Abstract: In 1998, Toyota Motor Corporation adopted intake valves and exhaust valves made of titanium-based alloys for the engine of its Altezza. Both valves were manufactured via a newly developed cost-effective powder metallurgy process. The exhaust valve is made of a newly developed titanium metal-matrix composite (MMC). The valve has achieved sufficient durability and reliability with a manufacturing cost acceptable for the mass-produced automobile engine components.

Piston type compressor

Abstract: A piston-type compressor includes a housing, a drive shaft supported on the housing, a communication hole formed inside the drive shaft, a valve mechanism, and a cylindrical body. The cylindrical body is inserted in the communication hole to disconnect a residual gas bypass passage and the communication hole from each other and to open the interior space of the cylindrical body to the communication hole. The valve mechanism includes an annular space defined outside the cylindrical body in the communication hole and multiple connection holes providing communication between the annular space and communication passages. The residual gas bypass passage is formed of the annular space and the multiple connection holes.

Microstructure and strength of quasicrystal containing extruded Mg-Zn-Y alloys for elevated temperature application

Abstract: Microstructural studies have been made on alloys Mg95Zn4.2Y0.8 and Mg92.5Zn6.5Y containing icosahedral quasicrystalline phase extruded at two different temperatures of 523 K and 673 K and correlated to room temperature and higher temperature tensile strength. Icosahedral phase occurred as particles about half micron size at grain boundaries and as nano-sized precipitates in the matrix. Solutionizing at 673 K (1 h) was employed followed by annealing at 473 K for finer precipitation in the matrix. Solutionizing produced a fine precipitation of a ternary phase τ1 in the matrix of the Mg95Zn4.2Y0.8 alloy, replaced by icosahedral precipitates on annealing. The Mg92.5Zn6.5Y alloy containing larger volume fraction of icosahedral phase showed higher strength. Solutionizing produced a composite of icosahedral and a H–Mg25Zn58Y17 hexagonal phase composite. Yield stresses of over 250 MPa at room temperature (elongation 15–20%) and 150 MPa at 473 K (UTS 240 MPa, elongation 40%) were obtained upon post extrusion annealing.

Deceleration control apparatus and method for a vehicle

Abstract: A declaration control apparatus and method for a vehicle, which performs deceleration control such that a deceleration acting on the vehicle becomes equal to a target deceleration by an operation of a brake system which applies a braking force to the vehicle and a shift operation which shifts a transmission of the vehicle into a relatively low speed or speed ratio, increases the target deceleration over time at a predetermined gradient to a predetermined value when a determination that there is a need to shift the transmission into a relatively low speed or speed ratio has been made, and after the target deceleration reaches the predetermined value, maintains the target deceleration at a generally constant value. As a result, a deceleration transitional characteristic of the vehicle is able to be improved.

Online convex optimization in the bandit setting: gradient descent without a gradient

Abstract: We consider a the general online convex optimization framework introduced by Zinkevich. In this setting, there is a sequence of convex functions. Each period, we must choose a signle point (from some feasible set) and pay a cost equal to the value of the next function on our chosen point. Zinkevich shows that, if the each function is revealed after the choice is made, then one can achieve vanishingly small regret relative the best single decision chosen in hindsight. We extend this to the bandit setting where we do not find out the entire functions but rather just their value at our chosen point. We show how to get vanishingly small regret in this setting. Our approach uses a simple approximation of the gradient that is computed from evaluating a function at a single (random) point. We show that this estimate is sufficient to mimic Zinkevich's gradient descent online analysis, with access to the gradient (only being able to evaluate the function at a single point).

Vehicle integrated control system

Abstract: An integrated control system includes a main control system (accelerator) controlling a driving system, a main control system (brake) controlling a brake system, and a main control system (steering) controlling a steering system, an adviser unit generating and providing information to be used at each control system based on environmental information around the vehicle or information related to a driver, an agent unit generating and providing information to be used at each of the main control systems to cause the vehicle to realize a predetermined behavior, and a supporter unit generating and providing information to be used at each of the main control systems based on the current dynamic state of the vehicle.

Outdoor performance of large scale DSC modules

Abstract: To elucidate possible challenges for outdoor practical use of dye-sensitized solar cells, outdoor performance of large scale DSC modules made of series-connected 64 DSC cells have been examined for a half year. This is almost the first long term outdoor test of full-fledged DSC modules. Although DSC modules still need the larger area than conventional Si solar cell modules to attain the same rated output because of lower rated energy conversion efficiency, the measured data teach that DSC modules yearly generated 10–20% more electricity than conventional crystalline-Si modules of the same rated output power. This result also teaches that the energy conversion efficiency obtained by the certified measurement under 1 Sun condition does not always coincide with the electricity generated outdoors yearly, and is not a crucial measure to evaluate the performance of solar cells. The outputs of four modules showed similar monotonous slow and steady decreases, showing potential outdoor use of DSC. Simultaneously, it indicates that there are still remaining challenges to overcome one by one in attaining higher performance keeping long term stability.

Distributed request routing

Abstract: A plurality of servers for processing client requests forward the requests among themselves to achieve a balanced load. When a server initially receives a client request, it randomly selects another of the plurality of servers, referred to as a first-chance server, and forwards the request to this server. Upon receiving the request, the first-chance server determines if it is overloaded and if not, processes the request. However, if overloaded, the first-chance server compares its load to the load of one or more predetermined next-neighbor servers. If the next-neighbor server(s) are more loaded than the first-chance server, the first-chance server processes the request. Otherwise, the first-chance server forwards the request to the least loaded next-neighbor server. The next-neighbor receiving the request either processes it directly, or alternatively, based on its current load and that of its next-neighbor server(s), forwards the request to another next-neighbor server for processing.