Electron transport in InGaO3(ZnO)m (m=integer) studied using single-crystalline thin films and transparent MISFETs

We have investigated the characteristics of transparent metal-insulator-semiconductor field-effect transistors (MISFETs) fabricated using InGaO₃(ZnO)_m (m=integer) single-crystalline thin films as n-channel layers and amorphous alumina as gate insulator films. The MISFETs exhibit good characteristics such as insensitivity to visible light illumination, off-current as low as ∼1 nA with a positive threshold voltage of ∼3 V and on/off current ratio of 10⁵. The field-effect mobility increased from ∼1 to ∼10 cm² (V s)⁻¹ as the m-value increased. Room temperature Hall mobility also increased. However, unexpectedly these values were lower than the field-effect mobility. It is explained by existence of shallow localized state in the homologous compounds.     

Effects of glucose load on brain extracellular lactate concentration in conscious rats using a microdialysis technique

Changes in the brain lactate concentration in cerebral extracellular fluid (ECF) during intravenous infusion of glucose and local administration of glucose were investigated in adult, conscious, unrestrained rats, with a microdialysis probe in the posterior hippocampus. The rats were infused intravenously with either 25% sucrose solution or 25% glucose solution at a rate of 16.6 microliters.min-1.100 g-1 for three hours. The blood glucose concentration reached 17.0 +/- 2.6 mM at the end of the glucose infusion, and brain ECF glucose showed a parallel change with the blood glucose concentration and increased to 2.37 +/- 0.30 mM. However, blood and brain ECF glucose concentrations did not change in animals infused with the sucrose solution. On the other hand, the blood lactate concentration in the glucose-infused group also increased from 0.93 +/- 0.18 mM to 2.85 +/- 0.39 mM at the end of the glucose infusion, which was significantly higher than that measured in the sucrose-infused group. The blood lactate level in the glucose-infused group returned to the basal level by the end of the experiment. Brain ECF lactate concentrations increased from 1.21 +/- 0.06 mM to 1.69 +/- 0.11 mM in glucose-infused animals, but did not change in the sucrose-infused animals. The brain ECF lactate concentration showed a positive correlation with the brain ECF glucose concentration in glucose-infused animals. Another group of rats was administered glucose locally for 90 min after substitution of artificial cerebrospinal fluid.(ABSTRACT TRUNCATED AT 250 WORDS)     

STEAM DRYING TECHNOLOGIES: JAPANESE R&D

This report reviews some fundamental and practical aspects of steam drying technologies based mainly on studies published in Japan. Steam drying kinetics, and some industrial technologies particularly for drying of foods, textiles and sludges are reviewed with focus on quality of dried material, drying time, dryer selection and energy recovery from steam dryer exhaust. For energy recovery, heat pump technologies are outlined along with characteristics of different types of steam compressors. A new process is proposed for steam drying; it combines a direct-indirect dryer followed by a direct steam dryer for internal moisture removal.     

The C-terminus of c-ABL is required for proliferation and viability signaling in a c-ABL/erythropoietin receptor fusion protein

Activated ABL oncogenes cause B-cell leukemias in mice and chronic myelogenous leukemia in humans. However, the mechanism of transformation is complex and not well understood. A method to rapidly and reversibly activate c-ABL was created by fusing the extra-cytoplasmic and transmembrane domain of the erythropoietin (EPO) receptor with c-ABL (EPO R/ABL). When this chimeric receptor was expressed in Ba/F3 cells, the addition of EPO resulted in a dose-dependent activation of c-ABL tyrosine kinase and was strongly antiapoptotic and weakly mitogenic. To evaluate the contributions of various ABL domains to biochemical signaling and biological effects, chimeric receptors were constructed in which the ABL SH3 domain was deleted (triangle upSH3), the SH2 domain was deleted (triangle upSH2), the C-terminal actin-binding domain was deleted (triangle upABD), or kinase activity was eliminated by a point mutation, K290M (KD). The mutant receptors were stably expressed in Ba/F3 cells and analyzed for signaling defects, proliferation, viability, and EPO-induced leukemia in nude mice. When compared with the ability of the full-length EPO R/ABL receptor to induce proliferation and support viability in vitro, the triangle upSH3 mutant was equivalent, the triangle upSH2 mutant was moderately impaired, and the triangle upABD and KD mutants were profoundly impaired. None of these cell lines caused leukemia in mice in the absence of pharmacological doses of EPO. However, in mice treated with EPO (10 U/d), death from leukemia occurred rapidly with wild-type and triangle upSH3. However, time to death was prolonged by at least twofold for triangle upSH2 and greater than threefold for triangle upABD. This inducible model of ABL transformation provides a method to link specific signaling defects with specific biological defects and has shown an important role for the C-terminal actin-binding domain in proliferation and transformation in the context of this receptor/oncogene.     

A 10 bit 20 MS/s 3 V supply CMOS A/D converter

A 10 bit CMOS A/D converter with 3 V power supply has been developed for being integrated into system VLSI's. In this A/D converter, redundant binary encoders named “twin encoders” enhance tolerance to substrate noise, together with employing differential amplifiers in comparators. The bias circuit using a replica of the amplifier is developed for biasing differential comparators with 3 V power supply. Subranging architecture along with a multilevel tree decoding structure improves dynamic performance of the ADC at 3 V power supply. The A/D converter is fabricated in double-polysilicon, double-metal, 0.8 μm CMOS technology. The experimental results show that the ADC operates at 20 MS/s and the twin encoders suppress the influence of substrate noise effectively. This ADC has a single power supply of 3 V, and dissipates 135 mW at 20 MS/s operation     

The Kinetic Stability of Cationic Benzyl Titanium Complexes that Contain a Linked Amido-Cyclopentadienyl Ligand: The Influence of the Amido-Substituent on the Ethylene Polymerization Activity of “Constrained Geometry Catalysts”

Cationic benzyl titanium complexes [Ti(η⁵: η¹-C₅Me₄SiMe₂NR')-(CH₂Ph)]⁺ were cleanly formed by the reaction of the dibenzyl titanium complexes [Ti(η⁵: η¹-C₅Me₄SiMe₂NR')(CH₂Ph)₂] with B(C₆F₅)₃ and [Ph₃C][B(C₆F₅)₄] in bromobenzene. NMR spectroscopic studies suggest that the benzyl titanium cations contain a fluxional η²-coordinated benzyl ligand. Kinetic analysis showed that the benzyl titanium cations decompose according to first-order kinetics and that the amido substituents R' (R' = Me, ⁱPr, ^tBu) in the linked amido-cyclopentadienyl ligand influence the lability of these benzyl titanium cations. The order of the kinetic stability of the benzyl titanium cations was found for both anions to follow the order R' = Me > ⁱPr > ^tBu. The benzyl titanium cations generated with [Ph₃C][B(C₆F₅)₄] were found to undergo faster decomposition than those generated with B(C₆F₅)₃. The ethylene polymerization activity order for both systems was found to be the reverse: R' = ^tBu > ⁱPr > Me. The decomposition of the benzyl titanium cations was suggested to occur via C—H activation with concomitant toluene elimination.     

Numerical simulation of parallel-plate particle separator for estimation of charge distribution of PM2.5

A numerical simulation of an instrument that is used to measure the charging state of PM2.5 is conducted in order to clarify its measurement uncertainty and to improve its performance. The instrument, a parallel-plate particle separator (PPPS), is designed to classify aerosol particles according to their charging states and measure their quantities. The trajectories of submicron particles in the PPPS are numerically analyzed using the Lagrangian particle tracking method, taking into account the Brownian force and the electrostatic force. First, it is confirmed that the deterioration in the classification accuracy observed in the experiment is due to Brownian diffusion. The optimal condition that improves the accuracy is investigated through a parametric study by varying the balance of flow rates at the inlets, the geometry of the inlet and exit sections, and the applied voltage. It is found that decreasing the flow rate of the central inlet for aerosol or narrowing the central inlet improves the accuracy. The dependence of the accuracy on the flow rate is found to be in accordance with the experimental results. For charged particles, an optimum voltage that maximizes the classification accuracy is found. On the basis of the simulation results, we propose a method to determine the charge distribution of aerosol from the number of particles counted at each exit of the PPPS. In the test assuming aerosol in the air, the charge distribution determined from the number count at the exits is found to perfectly agree with the charge distribution specified at the inlet.

Copyright © 2019 American Association for Aerosol Research     

Self-aligned fabrication of single crystal diamond gated field emitter array

This paper describes a self-aligned fabrication process for diamond gated field emitter array (FEA). Utilizing the non-conformal coverage sputtering conditions of silicon oxide, an interesting “sphere on cone” structure is formed on diamond nano tip array, which is the key point of gate hole opening process. This structure causes shadowing at certain regions of side-wall during Ti / Au gate metal deposition. Removal of “sphere” by wet etching leads to the successful fabrication of a single crystalline diamond gated FEA. Scanning electron microscope observations reveal the fabrication of a uniform emitter array with tip radius of curvature (20 nm) and gate hole (1.4 μm). We also confirmed that no noticeable physical damage exists on tip. In field emission characteristics of the fabricated single crystal diamond gated FEA, gate voltage control of field emission current is realized.     

Separation of Polyvinyl Chloride from Plastic Mixture by Froth Flotation after Surface Modification with Ozone

Selective modification by ozonation for the surface of polyvinyl chloride (PVC) was evaluated to separate PVC from the other plastics, polyethylene terephthalate (PET), polycarbonate (PC) and polymethyl methacrylate (PMMA), with almost the same density as PVC by the froth flotation process. Ozonation could selectively decrease the contact angles of flexible PVC from 87.5 degrees to 68.4 degrees and rigid PVC from 90.3 degrees to 66.9 degrees, whereas little decreases in the contact angle were observed for other plastics. This would be due to the replacement of the chloride group on the surface of PVC, into hydrophilic functional groups; carbonyl, carboxyl and ester group. The PVC was successfully separated from the other plastics by the froth flotation process after the selective surface modification by ozonation.     

New type of tin support for hydroprocessing catalyst

TiN supported molybdenum sulfide catalysts showed much higher activity for cleavage of C-C bonds than oxide supported molybdenum sulfide catalysts, indicating the possibility of a new generation of supports for hydroprocessing catalysts.