Dynamic infrared measurements of poly(vinyl chloride) in the vicinity of the glass transition

The temperature dependences of some selected infrared bands of poly(vinylchloride) in the vicinity of the glass transition were examined. The intensities of 1333 and 1427 cm^?1 bands changed discontinuouly at T_g; on the other hand, 2920 cm^?1 did not show any significant changes at this temperature. From these results, the nature of the temperature dependence of infrared intensity of the polymer was discussed. The procedure introduced in this work offers a rapid method for the determination of the T_g as compared with the conventional infrared methods.     

Prediction of fatigue crack growth and experimental result on overlaod retardation

The phenomena of crack growth retardation are frequently observed under variable amplitude or irregular loading fatigue tests. This paper describes a prediction method on crack growth retardation caused by an overload during fatigue loads.The prediction reported in this paper is performed by the following procedure using the yield strength and vs. ΔK relationship of the material.

1. (1) Determination of the residual stress distribution caused by cyclic load and overload based on the Dugdale model.

2. (2) Determination of the effective residual stress intensity factor and effective stress intensity range (ΔK_eff).

3. (3) Prediction of the crack growth rate using ΔK_eff and vs. ΔK relationship of the material.

From the viewpoint to apply the prediction to a structural component, experiments have been carried out on steel pipes with an axial through thickness crack, which are subject to an overpressure during cyclic pressure. In the paper, the experimental results are compared with the prediction.     

Molecular Dynamic Simulation in Titanium Dioxide Polymorphs: Rutile, Brookite, and Anatase

Molecular dynamic (MD) simulations with a quantum correction were performed on the titanium dioxide polymorphs. Interatomic potential functions of our new model are composed of Coulomb, short-range repulsion, van der Waals, and Morse interactions. The energy parameters were empirically determined to reproduce the fundamental properties of rutile crystal. The optimized crystal structure of TiO₂, rutile, was in very good agreement with experimental data in the literature. For brookite and anatase, our MD simulations reproduced well the crystal structures and several physical properties, including volume thermal expansivity and bulk modulus. The present MD simulations with a new interatomic potential function and parameters successfully predicted the crystal structures of the titanium dioxide polymorphs.     

A kinetic study of nonoxidative dissolution of galena in aqueous acid solution

This paper presents the results obtained through a kinetic study of the nonoxidative dissolution of natural galena in hydrochloric acid and perchloric acid solutions with and without the addition of sodium chloride. Under the experimental conditions employed in this study, the dissolution rates were controlled by a chemical reaction on the surface of the galena sample. The galena dissolution rate is of the first order with respect to hydrochloric ion activity in hydrochloric acid and perchloric acid solutions. The addition of sodium chloride to the acid solutions greatly enhanced the dissolution rate. The effect of sodium chloride has two possible interpretations: First, it may be the result of an increase in hydrogen ion activity. Second, the enhancement of the dissolution rate observable at high sodium chloride concentration may be due to the specific adsorption of chloride ions or the surface complexing of chloride ions on the galena surface.     

Solution‐Processed Silicane Field‐Effect Transistor: Operation Due to Stacking Defects on the Channel

2D silicon nanomaterials have unique potential for use in applications owing to their many different exotic electronic properties. Field‐effect transistors are fabricated based on free‐standing silicanes through a solution process. Owing to the sensitive surface and the nanometer thickness, the devices require the use of fabrication conditions similar to those of lithium‐ion batteries to prevent oxidation of the sheets. Reliable transistor performance is observed at room temperature in a channel thinner than 3 nm, as drain voltage dependent transfer curves current modulation, depending on the edge effect of the silicane, although the transistor property is modest (hole mobility of 1.8 cm² V^?1 s^?1). The results suggest the feasibility of other air‐sensitive 2D nanomaterials for applications in nanoelectronic devices.     

Long‐Lived Flexible Displays Employing Efficient and Stable Inverted Organic Light‐Emitting Diodes

Although organic light‐emitting diodes (OLEDs) are promising for use in applications such as in flexible displays, reports of long‐lived flexible OLED‐based devices are limited due to the poor environmental stability of OLEDs. Flexible substrates such as plastic allow ambient oxygen and moisture to permeate into devices, which degrades the alkali metals used for the electron‐injection layer in conventional OLEDs (cOLEDs). Here, the fabrication of a long‐lived flexible display is reported using efficient and stable inverted OLEDs (iOLEDs), in which electrons can be effectively injected without the use of alkali metals. The flexible display employing iOLEDs can emit light for over 1 year with simplified encapsulation, whereas a flexible display employing cOLEDs exhibits almost no luminescence after only 21 d with the same encapsulation. These results demonstrate the great potential of iOLEDs to replace cOLEDs employing alkali metals for use in a wide variety of flexible organic optoelectronic devices.     

Brilliant cosmetic film for ambient displays,with cholesteric liquid crystal

We have successfully developed a cosmetic film with polymerized cholesteric material. The film features a variety of colors by helical pitch gradients, diffusive texture, and arbitrary color patterns. It hides the display when turned off, and transmits display images when turned on. We believe it could change the display in the OFF‐state from the conventional black wall to specially designed decorations. In addition, they can be applied to hidden sensors.     

Biomimetic Nanomaterial Strategies for Virus Targeting: Antiviral Therapies and Vaccines

The ongoing coronavirus disease 2019 (COVID-19) pandemic highlights the importance of developing effective virus targeting strategies to treat and prevent viral infections. Since virus particles are nanoscale entities, nanomaterial design strategies are ideally suited to create advanced materials that can interact with and mimic virus particles. In this progress report, the latest advances in biomimetic nanomaterials are critically discussed for combating viral infections, including in the areas of nanomaterial-enhanced viral replication inhibitors, biomimetic virus particle capture schemes, and nanoparticle vaccines. Particular focus is placed on nanomaterial design concepts and material innovations that can be readily developed to thwart future viral threats. Pertinent nanomaterial examples from the COVID-19 situation are also covered along with discussion of human clinical trial efforts underway that might lead to next-generation antiviral therapies and vaccines.