Showing papers by "Toyota published in 2002"

An ordered mesoporous organosilica hybrid material with a crystal-like wall structure.

Abstract: Surfactant-mediated synthesis strategies are widely used to fabricate ordered mesoporous solids in the form of metal oxides, metals, carbon and hybrid organosilicas. These materials have amorphous pore walls, which could limit their practical utility. In the case of mesoporous metal oxides, efforts to crystallize the framework structure by thermal and hydrothermal treatments have resulted in crystallization of only a fraction of the pore walls. Here we report the surfactant-mediated synthesis of an ordered benzene-silica hybrid material; this material has an hexagonal array of mesopores with a lattice constant of 52.5 A, and crystal-like pore walls that exhibit structural periodicity with a spacing of 7.6 A along the channel direction. The periodic pore surface structure results from alternating hydrophilic and hydrophobic layers, composed of silica and benzene, respectively. We believe that this material is formed as a result of structure-directing interactions between the benzene-silica precursor molecules, and between the precursor molecules and the surfactants. We expect that other organosilicas and organo-metal oxides can be produced in a similar fashion, to yield a range of hierarchically ordered mesoporous solids with molecular-scale pore surface periodicity.

Self-regeneration of a Pd-perovskite catalyst for automotive emissions control

Abstract: Catalytic converters are widely used to reduce the amounts of nitrogen oxides, carbon monoxide and unburned hydrocarbons in automotive emissions. The catalysts are finely divided precious-metal particles dispersed on a solid support. During vehicle use, the converter is exposed to heat, which causes the metal particles to agglomerate and grow, and their overall surface area to decrease. As a result, catalyst activity deteriorates. The problem has been exacerbated in recent years by the trend to install catalytic converters closer to the engine, which ensures immediate activation of the catalyst on engine start-up, but also places demanding requirements on the catalyst's heat resistance. Conventional catalyst systems thus incorporate a sufficient excess of precious metal to guarantee continuous catalytic activity for vehicle use over 50,000 miles (80,000 km). Here we use X-ray diffraction and absorption to show that LaFe0.57Co0.38Pd0.05O3, one of the perovskite-based catalysts investigated1,2,3,4 for catalytic converter applications since the early 1970s, retains its high metal dispersion owing to structural responses to the fluctuations in exhaust-gas composition that occur in state-of-the-art petrol engines5. We find that as the catalyst is cycled between oxidative and reductive atmospheres typically encountered in exhaust gas, palladium (Pd) reversibly moves into and out of the perovskite lattice. This movement appears to suppress the growth of metallic Pd particles, and hence explains the retention of high catalyst activity during long-term use and ageing.

Dissipative particle dynamics study of spontaneous vesicle formation of amphiphilic molecules

Abstract: A dissipative particle dynamics (DPD) simulation has been used to study the spontaneous vesicle formation of amphiphilic molecules in aqueous solution. The amphiphilic molecule is represented by a coarse-grained model, which contains a hydrophilic head group and a hydrophobic tail. Water is also modeled by the same size particle as adopted in the amphiphile model, corresponding to a group of several H2O molecules. In the DPD simulation, from both a randomly dispersed system and a bilayer structure of the amphiphile for the initial condition, a spontaneous vesicle formation is observed through the intermediate state of an oblate micelle or a bilayer membrane. The membrane fluctuates and encapsulates water particles and then closes to form a vesicle. During the process of vesicle formation, the hydrophobic interaction energy between the amphiphile and water is diminishing. It is also recognized that the aggregation process is faster in two-tailed amphiphiles than those in the case of single-tailed ones.

Self-assembly of biphenylene-bridged hybrid mesoporous solid with molecular-scale periodicity in the pore walls.

Abstract: A synthesis of ordered biphenylene-bridged mesoporous material with a crystal-like periodic pore wall structure is reported.

Sulfuric acid-functionalized mesoporous benzene-silica with a molecular-scale periodicity in the walls.

Abstract: Novel sulfuric acid-functionalized mesoporous benzene−silicas with a molecular-scale periodicity in the walls were derived from the mesoporous benzene−silica possessing mercaptopropyl groups by the oxidative transformation of −SH into −SO3H.

Foam processing and cellular structure of polypropylene/clay nanocomposites

Abstract: Polypropylene (PP)/clay nanocomposites (PPCNs) were autoclave-foamed in a batch process. Foaming was performed using supercritical CO 2 at 10 MPa, within the temperature range from 130.6°C to 143.4°C, i.e., below the melting temperature of either PPCNs or maleic anhydride-modified PP (PP-MA) matrix without clay. The foamed PP-MA and PPCN2 (prepared at 130.6°C and containing 2 wt% clay) show closed cell structures with pentagonal and/or hexagonal faces, while foams of PPCN4 and PPCN7.5 (prepared at 143.4°C, 4 and 7.5 wt% clay) had spherical cells. Scanning electron microscopy confirmed that foamed PPCNs had high cell density of 10 7 -10 8 cells/mL, cell sizes in the range of 30-120 μm, cell wall thicknesses of 5-15 μm, and low densities of 0.05-0.3 g/mL. Interestingly, transmission electron microscopic observations of the PPCNs' cell structure showed biaxial flow-induced alignment of clay particles along the cell boundary. In this paper, the correlation between foam structure and rheological properties of the PPCNs is also discussed.

Parking assisting device

Abstract: When a vehicle advances in parallel with a parking frame to reach an initial stop position, measurement of a distance to a parked vehicle is continuously performed by means of an ultrasonic sensor and a moving distance of the vehicle is simultaneously calculated using a signal from a wheel speed sensor. When actuating an in-line mode switch under a state where the vehicle stops in the initial stop position, a turning angle is calculated so as to enable appropriate in-line parking to the parking frame from an actual initial stop position, based on a deviation of the vehicle from a reference position for the initial stop measured by the ultrasonic sensor. Information on a driving operation that is necessary for back parking is provided to a driver via a speaker based on this turning angle and output from a yaw rate sensor.

Device for monitoring area around vehicle

Abstract: A back camera image from a back camera mounted on a rear portion of a vehicle body is displayed on a display mounted on the console inside the vehicle cabin when the vehicle is parallel parking. After the vehicle passes a steering direction reversal point in this state, a corner camera image from a corner camera mounted on a corner portion of a front portion of the vehicle body is displayed on the display when the vehicle nears a vehicle parked in front, or, more specifically, when an angle of the vehicle after it has reached the steering direction reversal point has reached a predetermined value. Guidance images may be overlaid upon the camera images during some or all of the parallel parking maneuver.

Vehicle periphery monitor

Abstract: A front camera for filming an area stretching forwards is disposed in a front portion of a vehicle. A side camera for filming an area stretching laterally and diagonally forwards is disposed in a lateral-left portion of the vehicle. An indicator display that can be visually recognized by a driver is disposed in a compartment of the vehicle. An amount of change in the direction of the vehicle, that is, a deflection angle of the vehicle is detected on the basis of a vehicle speed and a steering angle of a steering wheel, which have been detected by means of various sensors. After the indicator display has started displaying a lateral photo image filmed by the side camera, the photo image displayed by the indicator display is shifted from the lateral photo image filmed by the side camera to a front photo image filmed by the front camera if the deflection angle has reached a predetermined angle.

Vehicle insurance premium calculation system, on-board apparatus, and server apparatus

Abstract: This system comprises a usage status detection means for detecting the usage status of a vehicle, data input means for inputting data relating to the maintenance or management of a vehicle, and insurance premium calculation means for calculating vehicle insurance premiums based on detection results and inputted data.

Positional data utilizing inter-vehicle communication method and traveling control apparatus

Abstract: Predicted future positions are calculated (S 11 ) and arranged into packets (S 12 ) to be transmitted using a communication pattern (for example, a PN series) based on a time and a position of each packet (S 13 ). Another vehicle calculates its predicted position (S 21 ) and generates a communication pattern based on a result of calculation (S 22 ) so that the generated communication pattern is utilized for reception (S 23 ). Consequently, data associated with a future position of its own can be selected for enabling reception. An existence probability is calculated, and the state of another vehicle can be accurately understood from the communication of the calculated existence probability, thereby effectively reducing chance of collision.

Shifting bottleneck detection

Abstract: This paper provides a novel method for detecting bottlenecks in manufacturing systems and the shifting of these bottlenecks. All manufacturing systems are constrained by one or more bottlenecks. Improving the bottleneck will improve the whole system. Yet, finding the bottleneck is no trivial task. Furthermore, the system may change over time or due to random events, and subsequently the bottleneck may shift from one machine to another machine. The shifting bottleneck detection method determines the bottleneck based on the duration a machine is active without interruption. The method is very robust, easy to apply and able to detect the primary and secondary bottlenecks in a wide range of production systems. This allows the use of simulation to predict bottlenecks for both steady state and variable systems. The measurement of the likelihood of a machine being the bottleneck aids in the decision-making regarding the allocation of the available resources.

An obstacle detection method by fusion of radar and motion stereo

Abstract: In order to avoid collision with an object that blocks the course of a vehicle, measuring the distance to it and detecting positions of its side boundaries, are necessary. In the paper, an object detection method achieved by the fusion of millimeter-wave radar and a single video camera is proposed. We consider the method as the least expensive solution because at least one camera is necessary for lane marking detection. In the method, the distance is measured by the radar, and the boundaries are found from an image sequence, based on a motion stereo technique with the help of the distance measured by the radar. Since the method does not depend on the appearance of objects, it is capable of detecting not only an automobile but also other objects. Object detection by the method was confirmed through an experiment. In the experiment, both a stationary and a moving object were detected and a pedestrian as well as a vehicle was detected.

Nitrogen and oxygen isotopomeric constraints on the origins and sea-to-air flux of N2O in the oligotrophic subtropical North Pacific gyre

Abstract: [1] Although the oceans are a significant source of the greenhouse gas nitrous oxide (N2O) to the atmosphere, the magnitude and characteristics of this source are poorly constrained. We present here stable isotope and isotopomer (intramolecular distribution of 15N within the linear NNO molecule) results for N2O and oxygen stable isotopic data for dissolved O2 from Station ALOHA in the subtropical North Pacific gyre near Hawaii. The results indicate shallow (∼100–300 m) in situ N2O production. Results of isotope mass balance models constrain the rate of N2O production and the sea-to-air flux of N2O. Results of an isotope mass balance model that takes into account the ratios of the vertical gradients in the isotopic abundances of N, O, Nα (central N) and Nβ (terminal N) of N2O and the measured gradients of N2O concentration through the thermocline indicate that shallow in situ production contributed 40% to 75% of the sea-to-air flux of N2O. This model also indicates that the net sea-to-air flux of N2O was at least 0.4 μmol m−2 d−1 and could be as high as 1.0 μmole m−2 d−1. These model results are not statistically different from the sea-to-air flux of N2O calculated using an empirical relationship between wind speed and gas transfer rate (1.1 ± 0.7 μmole m−2 d−1) derived from measured values for wind speed, temperature and the surface mixed layer concentration of N2O. These results can be used to better constrain the global N2O budget.

Light propagation characteristics of straight single-line-defect waveguides in photonic crystal slabs fabricated into a silicon-on-insulator substrate

Abstract: Straight single-line defect optical waveguides in photonic crystal slabs are designed by the finite difference time-domain method and fabricated into a silicon-on-insulator (SOI) wafer. By employing an airbridge structure, clear light propagation for both polarizations is observed without any leakage along the waveguide. This experimental result is well explained by photonic bands of pure guided modes. Minimum propagation loss is estimated to be 11 dB/mm. This value is lower than that reported so far for three-line-defect waveguides with an SOI slab structure and almost comparable to that for an index confinement waveguide with a rectangular Si core. This propagation loss is dominated by the scattering loss by some irregularities. However, photonic crystal waveguides have the possibility of an essential lower scattering loss than in the index confinement waveguide because of the inhibition of radiation modes by the photonic bandgap.

Quantitative Detection of Mycoplasma genitalium from First-Pass Urine of Men with Urethritis and Asymptomatic Men by Real-Time PCR

Abstract: We developed a TaqMan-based real-time PCR assay for quantifying Mycoplasma genitalium. This assay is able to specifically quantify concentrations of the M. genitalium 16S rRNA gene ranging from 107 to 10 copies/reaction. Using the TaqMan assay, we quantified the M. genitalium 16S rRNA gene in first-pass urine of men with urethritis and asymptomatic men who were positive for M. genitalium by PCR- and phylogeny-based assay. Of 130 men with gonococcal urethritis (GU), five were positive for M. genitalium. The mycoplasma load for each specimen was <5 × 10 copies/ml. Of 84 men with chlamydial non-GU (CNGU), seven were positive for M. genitalium. One man had an M. genitalium load of <5 × 10 copies/ml, and six men had loads ranging from 1.1 × 107 to 2.7 × 102 copies/ml. Of 86 men with nonchlamydial NGU (NCNGU), 17 were positive for M. genitalium. The mycoplasma loads for these men ranged from 3.3 × 106 to 2.3 × 102 copies/ml. Of 76 asymptomatic men, only two were positive for M. genitalium. For these men, the loads were 2 × 102 and <5 × 10 copies/ml. The patients with NGU had significantly higher concentrations of M. genitalium in their first-pass urine than did men with GU (P < 0.01) or asymptomatic men (P < 0.05). In addition, M. genitalium loads were significantly higher in men with NCNGU than those in asymptomatic men (P < 0.05). The quantitative assessment of M. genitalium loads by the TaqMan assay will provide useful information for understanding the pathogenicity of this mycoplasma in the urogenital tract.

Chemical bonding of hydrogen in MgH2

Abstract: MgH2 is one of the promising base materials for hydrogen storage, which is a key technology of clean energy source. In this study, the bonding nature of hydrogen in MgH2 was fully uncovered by examining the charge density distribution of this substance obtained by the maximum entropy method from the synchrotron radiation powder data. MgH2 can be expressed as Mg1.91+ H0.26−, which is much weaker ionicity than the theoretical expectations. It also shows weak covalence between Mg and H. Though the bonding nature of hydrogen in MgH2 is rather complex, i.e., the mixture of ionic and covalent bonding, it is certain that hydrogen is weakly bonded to Mg, which must be a big advantage of hydrogenation–dehydrogenation of this substance.

Hybrid-vehicle drive system and operation method with a transmission

Abstract: A hybrid-vehicle drive method and system includes an internal combustion engine that includes an output shaft, a first electric motor/generator connected to the output shaft of the internal combustion engine via a power distribution mechanism, a wheel drive shaft connected to the output shaft of the internal combustion engine via the power distribution mechanism, a second electric motor/generator connected to the wheel drive shaft, and a transmission located on at least one of the wheel drive shaft and a connecting portion of the second electric motor/generator with the wheel drive shaft

Exhaust gas purifying apparatus for internal combustion engine

Abstract: An exhaust gas purifying apparatus including an HC absorbent located in an upstream region of a selective reduction type NOx catalyst for improving a NOx purification efficiency. In the exhaust gas purifying apparatus, an HC absorbing device is disposed upstream of a NOx catalyst converter arranged in an exhaust gas passageway. The selective reduction type NOx catalyst accommodated in the HC absorbing device uses a carrier, which is easy to absorb the HC when a temperature of the exhaust gas is lowered, and easy to desorb the HC when the temperature of the exhaust gas is raised, and a selective reduction type NOx catalyst accommodated in the NOx catalyst converter uses a carrier which has a strong absorption of HC for retention. In order to prevent a catalyst temperature of the NOx catalyst converter from being lowered to a temperature lower than a purification temperature window in an operating state of deceleration, an ECU corrects an opening degree of an EGR valve to be increased, and thereby a flow rate of the exhaust gas which flows into the NOx catalyst converter is decreased when an inlet gas temperature detected by an inlet gas temperature sensor is lowered to a temperature lower than a set temperature. Thus, lowering of the catalyst temperature is suppressed.

Electronic structure of misfit-layered calcium cobaltite

Abstract: We have performed the first-principles calculations on (Ca 2 CoO 3 ) 4 (CoO 2 ) 6 to understand electronic structures of the misfit-layered calcium cobaltite, (Ca 2 CoO 3 ) x CoO 2 , within the generalized gradient approximation.The optimized structure, consisting of a triple rocksalt-type Ca 2 CoO 3 subsystem and a CdI 2 -type CoO 2 subsystem in which their respective octahedra are significantly distorted, shows good agreement with recent experiment. The calculated electronic structures include two-dimensionally dispersive e g bands across the Fermi energy, which yield the p-type conductivity in the rocksalt subsystem, while the Fermi energy lies in the crystal-field gap of the d states in the CoO 2 subsystem. The spin-polarized calculations show that antiferromagnetic or ferrimagnetic ordering with a small net magnetic moment within the rocksalt subsystem is found to be the ground state, which gives a reasonable explanation of low-temperature behavior of the resistivity and the susceptibility observed in experiment.

Robust mixed /spl Hscr//sub 2///spl Hscr//sub /spl infin// filtering of 2-D systems

Abstract: This paper deals with several challenging problems of robust filtering for two-dimensional (2-D) systems. First of all, new linear matrix inequality (LMI) characterizations for the /spl Hscr//sub /spl infin// and /spl Hscr/2 norms of 2-D systems are introduced and thoroughly established. Based on these preparatory results, convex (LMI) characterizations for robust /spl Hscr//sub /spl infin//, /spl Hscr//sub 2/, and robust mixed /spl Hscr//sub 2///spl Hscr//sub /spl infin// filtering are derived. The efficiency and viability of the proposed techniques and tools are demonstrated through a set of numerical examples.

Production mechanism and global budget of N2O inferred from its isotopomers in the western North Pacific

Abstract: [1] We measured the intramolecular distribution of 15N as well as conventional nitrogen and oxygen isotope ratios in oceanic nitrous oxide (N2O) in the western North Pacific for the first time. In contrast to a nearly homogeneous vertical distribution of a bulk nitrogen isotope ratio, a wide variation in site preference for intramolecular 15N distribution was found, suggesting the subsurface and deep source mixing and the production mechanism in the ocean. The oceanic composition of N2O isotopomers quantitatively outlines the ocean as the most significant source after the terrestrial one.

Magnetism of layered cobalt oxides investigated by muon spin rotation and relaxation

Abstract: Muon spin rotation-relaxation $(\ensuremath{\mu}\mathrm{SR})$ spectroscopy has been used to investigate the magnetic properties of polycrystalline ${\mathrm{Ca}}_{3\ensuremath{-}x}{\mathrm{M}}_{x}{\mathrm{Co}}_{4}{\mathrm{O}}_{9}$ $(xl~0.5,M=\mathrm{Sr},\mathrm{Y},$ and Bi) and ${\mathrm{Na}}_{0.7}{\mathrm{CoO}}_{2}$ samples in the temperature range between 2.5 and 300 K. It was found that ${\mathrm{Ca}}_{3}{\mathrm{Co}}_{4}{\mathrm{O}}_{9}$ exhibits a magnetic transition at around ${T}_{c}=100\mathrm{K};$ at lower temperatures, two types of relaxation were observed using a weak transverse field $\ensuremath{\mu}\mathrm{SR}$ technique with $H=104\mathrm{Oe}:$ one with a fast relaxation rate ${\ensuremath{\lambda}}_{F}\ensuremath{\sim}10\ensuremath{\mu}{\mathrm{s}}^{\ensuremath{-}1}$ and the other with a slow ${\ensuremath{\lambda}}_{S}\ensuremath{\sim}0.1\ensuremath{\mu}{\mathrm{s}}^{\ensuremath{-}1}.$ Zero-field $\ensuremath{\mu}\mathrm{SR}$ measurements suggest the existence of an incommensurate spin-density-wave (SDW) state below ${T}_{c}$ (i.e., ${T}_{c}{=T}_{\mathrm{SDW}}),$ although a ferrimagnetic $M\ensuremath{-}H$ loop was observed by a dc susceptibility measurement below 19 K. The substitution of Y or Bi for Ca increased ${T}_{\mathrm{SDW}},$ while the substitution of Sr for Ca did not affect ${T}_{\mathrm{SDW}}.$ This indicates that the SDW transition depends strongly on the average valence of the Co ions. The related material ${\mathrm{Na}}_{0.7}{\mathrm{CoO}}_{2}$ showed no magnetic transitions below 30 K. Considering the difference between the crystal structures of ${\mathrm{Ca}}_{3}{\mathrm{Co}}_{4}{\mathrm{O}}_{9}$ and ${\mathrm{Na}}_{0.7}{\mathrm{CoO}}_{2},$ we suggest that Co ions in the rocksalt-type layers of ${\mathrm{Ca}}_{3}{\mathrm{Co}}_{4}{\mathrm{O}}_{9}$ are likely to play a significant role in inducing the SDW transition around 100 K.

Synthesis of Cubic Hybrid Organic−Inorganic Mesostructures with Dodecahedral Morphology from a Binary Surfactant Mixture

Abstract: Synthesis of a cubic ethane−silica hybrid organic−inorganic mesoporous material using a binary surfactant mixture is reported. The system consists of ethane-bridged organosilica (BTME), polyoxyethylene alkyl ether [C12(EO)4; Brij 30], and the octadecyltrimethylammonium chloride (C18TMACl) surfactants in a basic medium. Powder X-ray diffraction analysis along with transmission electron microscope observation revealed a cubic symmetry of the mesophase and is consistent with the Pm3n space group. Scanning electron microscope micrographs of material exhibit a well-defined crystal-like dodecahedral morphology with a uniform particle size of 5 μm. Spectroscopic analyses confirmed that an ethane fragment is covalently linked to silica in surfactant-free material. The nitrogen adsorption isotherm shows a type-IV isotherm with a pore diameter of 28 A and a Brunauer−Emmett−Teller surface area of 744 m2g-1. The presented BTME−alkyltrimethylammonium−C12(EO)4−NaOH−H2O system greatly facilitates the synthesis of cubic...