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101.
The narrow-gap compound semiconductor PbTe has high Hall mobility. The Fermi surface at the L-point in the Brillouin zone
has large anisotropy. In this work, we measured thermomagnetic effects in PbTe thin films to confirm anisotropy of the Nernst
coefficient A
Ne and show Nernst mobility from the ratio of A
Ne and the Seebeck coefficient S: μ
Ne = A
Ne/S. Angular dependences of the Nernst voltage show that A
Ne is independent of the angle between the temperature gradient and the magnetic field, because of the high L-point symmetry.
The calculated Nernst mobility was compared with the Hall mobility. Because the former is smaller, the Mott equation cannot
explain the Seebeck coefficient at room temperature. 相似文献
102.
A mass gain for copper nanoparticles with a mean diameter of 20 nm in a 20% oxygen-nitrogen atmosphere was measured at 150-300 °C using thermogravimetry (TG). The mass gain equilibrium of the copper particles differed at each temperature, and a threshold temperature was recorded. Oxide products, consisting mainly of Cu2O, formed on the copper nanoparticles below the threshold temperature. Above the threshold temperature, there was an initial, and drastic, formation of Cu2O, which then changed to CuO. The activation energy for the oxidation of the copper nanoparticles that could be calculated from the rate of the mass gain was an indication of the nano-effect of the copper nanoparticles. 相似文献
103.
Akihiro YamanoHiromitsu Kozuka 《Thin solid films》2011,519(6):1772-1779
Polymethylmethacrylate (PMMA)-perhydropolysilazane (PHPS) hybrid thin films doped with spiropyran were prepared by spin-coating, which were then converted into 0.26-1.7 μm thick, spiropyran-doped PMMA-silica hybrid films by exposure treatment over aqueous ammonia. The spiropyran/(spiropyran + PHPS + PMMA) mass ratio was fixed at a high value of 0.2 so that the films exhibit visual photochromic changes in color, while the PMMA/(PMMA + PHPS) mass ratio, r, was varied. The spiropyran molecules in the as-prepared films were in merocyanine (MC) and spiro (SP) forms, with and without an optical absorption at 500 nm, at low (r ≤ 0.2) and high (r ≥ 0.4) PMMA contents, respectively. When PMMA content r was increased from 0 to 0.2, the degree of the MC-to-SP conversion on vis light illumination was enhanced, while at higher r's the spiropyran molecules underwent photodegradation. When the silica film (r = 0) was soaked in xylene under vis light, the spiropyran molecules were almost totally leached out, while not on soaking in the dark. On the other hand, no leaching occurred for the film of r = 0.2 either in the presence or absence of vis light. These suggest that the introduction of PMMA is effective in improving the chemical durability of the films, while the silica film (r = 0) is an interesting material with a photoresponsive controlled-release ability. The pencil hardness of the films decreased with increasing PMMA content, but remained over 9H at r ≤ 0.4. 相似文献
104.
Jun‐Ichi Itoh Ikuya Sato Hideki Ohguchi Kazuhisa Sato Akihiro Odaka Naoya Eguchi 《Electrical Engineering in Japan》2005,152(3):65-73
This paper proposes a novel control method based on the virtual AC/DC/AC conversion for the matrix converter. The virtual AC/DC/AC conversion method is a very simple strategy to control the input current and the output voltage for the matrix converter. There are two new topics proposed in this paper. First, this paper proposes the minimum switching loss modulation on the virtual rectifier. In our proposed modulation, only two arms switching in the virtual rectifier using DC link current control by the virtual inverter can obtain clean sinusoidal input current. Second, a novel lean controlled carrier modulation on the virtual inverter is proposed. The leans of the triangle carrier are controlled by the duty ratio of the rectifier side pulse. The lean controlled carrier reduces harmonic distortion of the input current by avoiding interference between the rectifier control and the inverter control. These new proposals are confirmed by simulation and experimental results. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 65–73, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20144 相似文献
105.
Tunnel-leakage currents become the dominant form of leakage as MOS technology advances. An electric-field-relaxation scheme that suppresses these currents is described. Cosmic-ray-induced multierrors have now become a serious problem at sea level. An alternate error checking and correction architecture for the handling of such errors is also described, along with the application of both schemes in an ultralow-power 16-Mb SRAM. A test chip fabricated by using 0.13-/spl mu/m CMOS technology showed per-cell standby-current values of 16.7 fA at 25/spl deg/C and 101.7 fA at 90/spl deg/C. The chip provided a 99.5% reduction in soft errors under accelerated neutron-exposure testing. 相似文献
106.
Summary Deuterium NMR measurements have been performed for main-chain polymer liquid crystals having structures such as {Ø-OC(O)-Ø-O(CD2)nO-Ø-C(O)O-Ø-O(CH2)nO}x with n = 9, 10. D-NMR spectra obtained in the nematic mesophase are compared with those previously reported for the dimer liquid crystals of the type NC---O(CD2)nO---CN with n = 9, 10, Although resolutions are relatively poor in the polymer spectrum, the general profiles of the spectra were found to be similar to those of the corresponding dimer. The results of the RIS analysis suggest that the spatial configurations of the spacer are nearly identical between the dimer and polymer. It has been concluded that the observed enhancement in the quadru-polar splittings should arise largely from a higher orientational ordering of the molecular axis in the polymeric system. 相似文献
107.
This paper proposes a boundary-element method using spatial eigenmodes for electromgnetic field analysis. Mapping the computation model with rotational symmetries, reflective symmetries or rotational symmetries including reflective symmetries to a group of spatial eigenmodes, the equivalent reduced models are obtained. In the method, the applicability becomes wide because arbitrary external source terms can be chosen. Furthermore, in a model including asymmetry regions, a new method which can save the merit of the symmetries is proposed. Finally, the validity of the proposed method is proved by numerical simulations. 相似文献
108.
A queueing system with K servers operates in the following manner. When the system is empty, arriving customers are attended by only one server. A set of forward threshold values is defined so that at epochs at which the number of customers in the system exceeds a forward threshold value an extra server is added. Similarly, a set of reverse threshold values is defined so that at epochs at which the number of customers in the system becomes less than a reverse threshold value one server is removed. The forward and reverse threshold values are assumed to be different. Closed-form occupancy distribution and mean delay of customers in the system are obtained by the Green's function method. 相似文献
109.
Ikuo Naito Kazuhiro Teshima Noboru Sato Hirofumi Sekito Akihiro Kinoshita 《应用聚合物科学杂志》1984,29(12):4115-4122
Photolysis of poly(3-buten-2-one) (PMVK), poly(4,4-dimethyl-1-penten-3-one) (PBVK), and poly(3-methyl-3-buten-2-one) (PMIK) were carried out in dioxane under oxygen or nitrogen bubbling. The main chain degradations of PBVK and PMIK were quenched and polymeric peroxides were produced. The heat treatment of the polymer irradiated in the presence of oxygen promoted the degradation. The photodegradation of PMVK was enhanced in the presence of oxygen. 相似文献
110.