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The thermodynamic properties of few-layer graphene arbitrarily stacked on LiNbO3 crystal were characterized by measuring the parameters of a surface acoustic wave as it passed through the graphene/LiNbO3 interface. The parameters considered included the propagation velocity, frequency, and attenuation. Mono-, bi-, tri-, tetra-, and penta-layer graphene samples were prepared by transferring individual graphene layers onto LiNbO3 crystal surfaces at room temperature. Intra-layer lattice deformation was observed in all five samples. Further inter-layer lattice deformation was confirmed in samples with odd numbers of layers. The inter-layer lattice deformation caused stick–slip friction at the graphene/LiNbO3 interface near the temperature at which the layers were stacked. The thermal expansion coefficient of the deformed few-layer graphene transitioned from positive to negative as the number of layers increased. To explain the experimental results, we proposed a few-layer graphene even–odd layer number stacking order effect. A stable pair-graphene structure formed preferentially in the few-layer graphene. In even-layer graphene, the pair-graphene structure formed directly on the LiNbO3 substrate. Contrasting phenomena were noted with odd-layer graphene. Single-layer graphene was bound to the substrate after the stable pair-graphene structure was formed. The pair-graphene structure affected the stacking order and inter-layer lattice deformation of few-layer graphene substantially.

Electrical transport properties of the nano-graphene oxide were investigated by measuring current-voltage characteristics in the wide temperature range of 15 K∼450 K. The n-GO is composed of nanometer-sized intact graphene-like sp2 domains embedded in the sp3 matrix which acts as a charge transport barrier between the highly conductive sp2 domains. The oxygen in the n-GO has the concentration of 4.43 at% in the form of oxygen functional groups. Below the conduction band, four discontinuous localized states with the activation energies of 1.92 meV, 3.27 meV, 5.54 meV, and 6.58 meV were observed. These activation energies decrease with decreasing oxygen concentration and increasing external electric field in the n-GO material. Moreover, we found that the direct tunneling of charge carrier through the sp3 barrier was a dominant transport mechanism for the n-GO material. Also, unlike the activation energy of charge carrier, the transport barrier was independent of both the concentration of the oxygen functional groups and external electric field. The transport barrier was mainly determined by insulation property of the sp3 structure.

Ageing behaviors of the positive electrode of lithium ion battery are characterized by measuring mechanical properties of the electrode reeds, such as resonance frequency and internal friction, as a function of temperature. In the measurements of the electrode reeds with a sandwich structure of active material film and current collector of Al foil, two thermally-activated relaxation processes can be observed on the polyvinylidene difluoride binder in the active material film. Namely, a surface-related relaxation at ~150 K and a relaxation corresponding to the β-phase transition at ~240 K in the polymer binder can be observed at high signal/noise ratio. The resonance frequency decreases and the internal friction increases after charge/discharge cycling. The changes in activation energies of the relaxation processes also indicate that the measurement of mechanical properties of the positive electrode is an effective method for characterizing ageing behaviors of the positive electrode as a whole.

The graphene/LiNbO3 structure exists in an interfacial stress-free state at the temperature at which the graphene was transferred onto the LiNbO3 substrate surface. Coupling of a surface acoustic wave with this structure revealed drastic changes in the properties of the propagating elastic wave around the critical temperature of the stress-free state. Three states, namely, tensile stress, stress-free, and compressive stress, were successively observed at the surface of the LiNbO3 substrate as the temperature was increased through the critical point. The interfacial stress increased prior to the occurrence of sliding friction and approached a constant value when the frictional force exceeded the van der Waals interaction between the graphene and LiNbO3. Consequently, the interfacial stress exhibited a step-like temperature dependence around the critical temperature of the stress-free state. The results obtained in this study indicate that the temperature used to prepare graphene layers on a substrate is a crucial parameter owing to the instability of the electrical and mechanical properties of the graphene/substrate in the vicinity of this temperature. Therefore, in the fabrication of graphene-based electronic devices, room temperature should be avoided during the preparation of the graphene layers on the substrate.

The electrical properties of microcrystalline Sc3N@C80 fullerene with fcc structure are studied by measuring both d.c. conductivity temperature dependence and a.c. impedance. Below 450 K the Sc3N@C80 sample has an energy band gap of 1.71 eV, which does not depend on the strength of the applied electric field. But when the temperature is above 450 K, a phase transition which results in a small band gap of 1.22 eV occurs under electric field strengths larger than 1 kV/cm. We also found from Cole–Cole plots of a.c. impedance that the contact resistance at the Au/Sc3N@C80 interface is less than that at the Au/C60 interface.

As a motive power in heavy construction machineries including mining and various construction works, a multi-cylinders type of diesel engine is very often used because of its high cost performance. Steady maintaining of diesel engine's operation is substantial in view of economic demands and environmental concerns. To realize this, a practice of early diagnosis and early repair are essential.In our previous study using a V-12 type of diesel engine installed on a bench, we demonstrated that a misfiring cylinder could be detected by statistical analysis method using rms value of the acceleration waveforms measured on a single point of the engine block.In this paper, the same experimentation and analyses as in the previous study were conducted for two practical machineries that loaded the same type engine of the previous study. Even though the engine was loaded on a practical machinery, it was found that a misfiring cylinder could be detected by the same way as in the previous study. In addition to the analyzing method in the previous study, in this study, we employed a wavelet transform method with the Gabor function as a window, and analyzed the acceleration waveforms. The results of wavelet analysis revealed that a misfiring cylinder could be detected visually from time-frequency charts. With the aid of statistical analysis using rms value, a misfiring cylinder in a multi-cylinder diesel engine can be doubly checked by wavelet analysis.

The effects of the external electric field on the height of the Schottky barrier at the Gd3N@C80/Au interface were studied by measuring current-voltage characteristics at various temperatures from 200 K to 450 K. The Gd3N@C80 sample with the conduction/forbidden/valence energy band structure had a face-centered cubic crystal structure with the average grain size of several nanometers. The height of the Gd3N@C80/Au Schottky barrier was confirmed to be 400 meV at a low electric field at room temperature. Moreover, the height decreases with the increasing external electric field through a change of permittivity in the Gd3N@C80 sample due to a polarization of the [Gd3]9+−[N3−+C806−] dipoles in the Gd3N@C80 molecule. The field-dependence of the barrier height can be described using a power math function of the electric field strength. The results of the field-dependent barrier height indicate that the reduction in the Schottky barrier is due to an image force effect of the transport charge carrier at the Gd3N@...

The current-voltage characteristics of the C70 solid with hexagonal closed-packed structures were measured in the temperature range of 250–450 K. The current-voltage characteristics can be described as a temporary expedient by a cubic polynomial of the voltage, i = a v 3 + b v 2 + c v + d. Moreover, the Meyer-Neldel temperature of the C70 solid was confirmed to be 310 K, at which a linear relationship between the current and voltage was observed. Also, at temperatures below the Meyer-Neldel temperature, the current increases with increasing voltage. On the other hand, at temperatures above the Meyer-Neldel temperature a negative differential conductivity effect was observed at high voltage side. The negative differential conductivity was related to the electric field and temperature effects on the mobility of charge carrier, which involve two variations in the carrier concentration and the activation energy for carrier hopping transport.

A traveling electric field in surface acoustic wave was introduced into the graphene/SiO2/Si sample in the temperature range of 15 K to 300 K. The coupling behaviors between the sample and the electric field were analyzed using two parameters, the intensity attenuation and time delay of the traveling-wave. The attenuation originates from Joule heat of the moving carriers, and the delay of the traveling-wave was due to electrical resistances of the fixed charge and the moving carriers with low mobility in the sample. The attenuation of the external electric field was observed in both Si crystal and graphene films in the temperature range. A large attenuation around 190 K, which depends on the strength of external electric field, was confirmed for the Si crystal. But, no significant temperature and field dependences of the attenuation in the graphene films were detected. On the other hand, the delay of the traveling-wave due to ionic scattering at low temperature side was observed in the Si crystal, but cannot be detected in the films of the mono-, bi- and penta-layer graphene with high conductivities. Also, it was indicated in this study that skin depth of the graphene film was less than thickness of two graphene atomic layers in the temperature range.

SAW attenuations in C70 thin films were measured between 16 and 380 K. The measurements were carried out at 80, 240 and 400 MHz. We obtained typical Debye type attenuations; the activation energy and relaxation time were 130 meV and 3.28×10−13 s, respectively. The results in C70 thin films were different from in C60 thin films for hysteresis and acoustic attenuation mechanism. This is the first report of the ultrasonic investigation in C70 thin films.

Stabilized zirconia is well known for long-range transport of oxygen ions which is caused by diffusion relaxation of oxygen vacancies. We used torsional vibrations to measure the temperature dependence of internal friction in yttria-stabilized zirconia (YSZ) doped with 9.5 mol % Y2O3 and calcia-stabilized zirconia (CSZ) doped with 12 mol % CaO. In the temperature range 300– 700 K , the internal friction peak exhibits anisotropy, different in YSZ from CSZ, which we attribute to localized relaxation of oxygen vacancies. The results imply that some oxygen vacancies are bound within the local structure, a greater number in CSZ than in YSZ, and suggest that the defect symmetry of local structure depends on the type of dopant ion.

The acoustic attenuation at 10 MHz in yttria-stabilized zirconia (ZrO2(Y)) was measured at temperatures between 300 and 600 K. The attenuation curve showed a relaxation peak, from which the activation energy was estimated to be 0.7±0.07 eV , in good agreement with the value obtained from dielectric constant of 0.66±0.07 eV . On the other hand, the measurement of ionic conductivity gave 0.92±0.1 eV . The conclusion is that in addition to diffusion of oxygen ions there exists a second, localised mechanism for relaxation.

Dielectric properties of the Au/C60 (OH)24-26/Au structure were studied by measuring a.c. impedance and d.c. current in a wide temperature range. Three dielectric response characteristics were identified from Cole-Cole plots of a.c. impedance and dielectric dissipation factor of the structure. First, the bulk resistance and capacitance of the structure were observed at frequencies below 10 Hz, regardless of preparation condition of the Au electrode. Secondly, an interfacial characteristic of the Au foil/C60 (OH)24-26 contact was observed as a peak of dielectric dissipation factor at frequency of 200 Hz. Thirdly, an interfacial characteristic of the Au paste/C60 (OH)24-26 contact was also observed as a peak of dielectric dissipation factor at frequency of 1.7×〖10〗^5 Hz.

We have long observed the changes of the Dalian areas using remotely sensed image time series from the point of view of human activities. We employ Landsat TM and ETM+ data to evaluate quantitatively the rate of progress due to its modernization in connection with weather and geographical conditions since such a research is still in an early stage of its development. The analysis by unsupervised classification techniques indicates a steady increase of land area and a steady decrease of vegetation in the Dalian areas irrespective of the difference of the methods. These facts show that the present approach gives us a measure of human activities.

The transport property of carriers passing through a nanocrystalline Lu3N@C80/Au interface has been studied by measuring impedance under various alternating voltages and DC biases. A depletion layer thicker than 110 µm is recognized in the Lu3N@C80/Au Schottky contact. Such a thick depletion layer indicates that the formation of space charge in the nanocrystalline Lu3N@C80 phase is difficult owing to an increase in LUMO energy, i.e., a decrease in the electron affinity of the Lu3N@C80 molecule. A high interfacial resistance is found to increase the transmission time of the carriers passing through the Lu3N@C80/Au Schottky contact. Such a high interfacial resistance may be ascribed to the low mobility of the carriers in the nanocrystalline Lu3N@C80 phase.

We applied a noncontacting surface acoustic wave technique to measure the conductivity of aligned multiwall carbon nanotube films. By changing intensities of the parallel and perpendicular electric field components at the surface of the film sample, we observed different temperature dependencies of the conductivity. It was found that the temperature dependence of the conductivity parallel to the tube axis is comparable to that of a single-wall carbon nanotube, namely, there is a metallic–nonmetallic transition at temperature of 280 K. On the other hand, the temperature dependence of the conductivity perpendicular to the tube axis is similar to that of a graphene sheet.

Nanoscale cubic SiC particle film is grown on Si substrate by hydrogen plasma sputtering of a SiC target. Before the film growth an amorphous SiC buffer layer of about 100 nm thickness is prepared on the Si substrate. By annealing the buffer layer in hydrogen atmosphere, the nanoscale cubic SiC particle film can be grown on the buffer layer on Si. Particle size, composition and crystallinity of the film depend on the composition, the crystallinity and the surface morphology of the buffer layer.

Longitudinal ultrasonic attenuation in yttria-stabilized zirconia [ZrO2(Y)] was measured at frequencies of 10 MHz and 120 MHz and at temperatures between 300 and 600 K. The temperature variation was strongly anisotropic, the maximum effect being observed in the direction. At 10 MHz a relaxation peak was observed from which an activation energy of 0.7 ±0.07 eV could be estimated. A similar figure was obtained from dielectric constant measurements, but the ionic conductivity yielded a higher value of 0.92 ±0.1 eV. Our conclusion is that there are two separate hopping processes for oxygen ions, one between Zr-related sites which can percolate the crystal and hence produce conduction, and another between Y-related sites which are localized.