The localization of charge carriers by electronic repulsion was suggested by Mott in the 1930s to explain the insulating state observed in supposedly metallic NiO. The Mott metal-insulator transition ...has been subject of intense investigations ever since
-not least for its relation to high-temperature superconductivity
. A detailed comparison to real materials, however, is lacking because the pristine Mott state is commonly obscured by antiferromagnetism and a complicated band structure. Here we study organic quantum spin liquids, prototype realizations of the single-band Hubbard model in the absence of magnetic order. Mapping the Hubbard bands by optical spectroscopy provides an absolute measure of the interaction strength and bandwidth-the crucial parameters that enter calculations. In this way, we advance beyond conventional temperature-pressure plots and quantitatively compose a generic phase diagram for all genuine Mott insulators based on the absolute strength of the electronic correlations. We also identify metallic quantum fluctuations as a precursor of the Mott insulator-metal transition, previously predicted but never observed. Our results suggest that all relevant phenomena in the phase diagram scale with the Coulomb repulsion U, which provides a direct link to unconventional superconductivity in cuprates and other strongly correlated materials.
In this paper, high-performance bottom-gate thin-film transistors (TFTs) with transparent zinc oxide (ZnO) channels have been developed. The ZnO film for active channels was deposited by RF magnetron ...sputtering. The crystallinity of the ZnO film drastically improved when it was deposited on a doublelayer SiO x /SiN x gate insulator. In order to achieve a ZnO TFT back-plane for liquid-crystal display (LCD) with the required pattern accuracy, dry etching of the ZnO film in an Ar and CH 4 chemistry has been developed. The etching rate and tapered profile of the ZnO film could be controlled by the Ar content in the etching gases of Ar and CH 4 . The saturation mobility (mu sat ) of the ZnO TFT strongly depended on a gate voltage. A mu sat of 5.2 & cm 2 .(V .s) -1 at V GS = 40 V and V DS = 10 V, and an on/off-current ratio of 2.7 x 10 7 were obtained. A drain-current uniformity of plusmn7% was achieved within a radius of 20 mm from the substrate center. A 1.46 -in diagonal LCD with 61 600 pixels has been driven by the ZnO-TFT back-plane. A moving picture image was available on fabricated LCD driven by the ZnO TFTs.
Transparent and conductive Al-doped ZnO (AZO) thin films were deposited on substrates including alkali-free glass, quartz glass, Si, and SiO
2 buffer layer on alkali-free glass by using radio ...frequency magnetron sputtering. The effects of different substrates on the structural, electrical and optical properties of the AZO films were investigated. It was found that the crystal structures were remarkably influenced by the type of the substrates due to their different thermal expansion coefficients, lattice mismatch and flatness. The AZO film (100 nm in thickness) deposited on the quartz glass exhibited the best crystallinity, followed sequentially by those deposited on the Si, the SiO
2 buffer layer, and the alkali-free glass. The film deposited on the quartz glass showed the lowest resistivity of 5.14
×
10
−
4
Ω cm among all the films, a carrier concentration of 1.97
×
10
21 cm
−
3
and a Hall mobility of 6.14 cm
2/v·s. The average transmittance of this film was above 90% in the visible light spectrum range. Investigation into the thickness-dependence of the AZO films revealed that the crystallinity was improved with increasing thickness and decreasing surface roughness, accompanied with a decrease in the film resistivity.
Fast microtomography combined with local crack driving force analysis has been employed to analyze crack-tip stress/strain singularities in an aluminum alloy. The application of fast microtomography ...has made it possible to observe real crack initiation and propagation behaviors without intermediate unloading. The details of a crack and its local propagation behaviors are readily observed with this technique along with evidence of microstructure/crack interactions. After a preliminary investigation of the achieved spatial resolution, we show that conventional stationary and growing crack singularities can be quantitatively validated by deriving the local crack opening displacement. This is to our knowledge the first three-dimensional validation of conventional fracture mechanics during a real time continuous experiment that has been mainly developed via surface observations so far. We also reveal that there is a spatial transition from a stationary crack singularity to a growing crack singularity in addition to the well-known temporal transition that occurs with the onset of crack propagation. Local crack propagation behaviors are also discussed on the basis of this validation. To separate the effects of complex crack geometry from those of microstructure, we also perform an image-based numerical simulation.
Summary
The head lift exercise (HLE) is the most common exercise for strengthening the swallowing musculature in clinical situations. This study investigated whether a change in the backrest angle of ...a bed influences swallowing musculature activity and physical strain during the HLE and whether it can generate an appropriate exercise load for swallowing musculature activity for older women compared with younger women. Participants were 10 elderly women and 10 young women, each of whom performed the HLE with a backrest randomly angled at 0°, 15°, 30° and 45°. The activity of the suprahyoid, infrahyoid and sternocleidomastoid muscles was assessed with electromyography. The perception of fatigue was measured with the Borg Rating of Perceived Exertion Scale. The activity of the infrahyoid and sternocleidomastoid muscles in elderly women was significantly lower when the angle of the backrest was raised to 45° vs 0°. In both groups, the Borg rating decreased significantly at the 30° and 45° backrest positions vs the 0° and 15° positions. The activity required for the suprahyoid and infrahyoid muscles in elderly women at a 30° backrest position was almost equal to the activity required by these muscles in young women at a 0° backrest position. In elderly women, it is possible that the HLE with the backrest at a 30° angle may be easier and provide a more appropriate exercise load for strengthening the swallowing muscles.
OBJECTIVES
Recently, the double-switch operation for congenitally corrected transposition of the great arteries has become the procedure of choice in our institute; however, the long-term follow-up ...is uncertain.
METHODS
From 1983 to 2010, 90 patients with congenitally corrected transposition of the great arteries underwent the double-switch operation, which comprised of an atrial switch plus intraventricular rerouting (with or without extracardiac conduits) in 72 patients (group I), and an atrial switch plus arterial switch in 18 patients (group II). The mean age at operation was 7.4 years old in group I vs. 4.3 years old in group II. The mean follow-up period was 12.9 years in group I vs. 10.9 years in group II. Hospital and late mortality, reoperation, arrhythmia and NYHA status were analysed retrospectively.
RESULTS
The Kaplan-Meier survival, including hospital and late mortality at 20 years, was similar (75.7% in group I vs. 83.3% in group II). The freedom from reoperation was 77.6% in group I (redo-Rastelli in five patients, subaortic stenosis resection in three, tricuspid valve replacement in one and mitral valve plasty in one) vs. 94.1% in group II (P < 0.05 vs. group I; aortic valve replacement in one). The freedom from arrhythmia was 57.1% in group I vs. 78.6% in group II (P < 0.05 vs. group I). The ratio of NYHA class I to II at outpatient clinic was similar (86% in group I vs. 86% in group II).
CONCLUSIONS
The long-term prognosis of the double-switch operation for congenitally corrected transposition of the great arteries was acceptable. In particular, an atrial switch plus arterial switch could be performed with low morbidity, and it should be considered as the optimal procedure.
A vertically stacked image sensor composed of green (G)- and red (R)-sensitive organic photoconductive films, each having a thin-film transistor (TFT) that uses a transparent zinc oxide (ZnO) channel ...to read out a signal generated in the organic film, was fabricated. The effective number of pixels of the ZnO-TFT circuits was 1410 (47 times 30), and their pitch was 600 mum. The current on/off ratio and turn-on voltage of the ZnO-TFT were over 10 5 and 1.5 V, respectively. The G- and R-sensitive organic photoconductive films showed excellent wavelength selectivity: the peak wavelength of the G-sensitive film was 540 nm, and that of the R-sensitive one was 700 nm. A color image with a resolution corresponding to the number of pixels was obtained by a shooting experiment with the fabricated image sensor, which clearly demonstrated color separation in the depth direction of the image sensor, using a stacked structure of wavelength-selective organic films with ZnO-TFT readout circuits.
Recently, MLS (Mobile Laser Scanning) has been successfully used in a road maintenance. In this paper, we present the application of MLS for the inspection of clearance along railway tracks of West ...Japan Railway Company. Point clouds around the track are captured by MLS mounted on a bogie and rail position can be determined by matching the shape of the ideal rail head with respect to the point cloud by ICP algorithm. A clearance check is executed automatically with virtual clearance model laid along the extracted rail. As a result of evaluation, the accuracy of extracting rail positions is less than 3 mm. With respect to the automatic clearance check, the objects inside the clearance and the ones related to a contact line is successfully detected by visual confirmation.
The Mott insulator κ−(BEDT−TTF)2Ag2(CN)3 forms a highly-frustrated triangular lattice of S=1/2 dimers with a possible quantum-spin-liquid state. Our experimental and numerical studies reveal the ...emergence of a slight charge imbalance between crystallographically inequivalent sites, relaxor dielectric response, and hopping dc transport. In a broader perspective we conclude that the universal properties of strongly-correlated charge-transfer salts with spin liquid state are an anion-supported valence band and cyanide-induced quasidegenerate electronic configurations in the relaxed state. The generic low-energy excitations are caused by charged domain walls rather than by fluctuating electric dipoles. They give rise to glassy dynamics characteristic of dimerized Mott insulators, including the sibling compound κ−(BEDT−TTF)2Cu2(CN)3.
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