Thin TiO2 grown by metal–organic chemical vapor deposition on (NH4)2S x -treated InP

The electrical characteristics of thin TiO₂ films prepared by metal–organic chemical vapor deposition grown on a p-type InP substrate were studied. For a TiO₂ film of 4.7 nm on InP without and with ammonium sulfide treatment, the leakage currents are 8.8×10⁻² and 1.1×10⁻⁴ A/cm² at +2 V bias and 1.6×10⁻¹ and 8.3×10⁻⁴ A/cm² at −2 V bias. The lower leakage currents of TiO₂ with ammonium sulfide treatment arise from the improvement of interface quality. The dielectric constant and effective oxide charge number density are 33 and 2.5×10¹³ cm², respectively. The lowest mid-gap interface state density is around 7.6×10¹¹ cm⁻² eV⁻¹. The equivalent oxide thickness is 0.52 nm. The breakdown electric field increases with decreasing thickness in the range of 2.5 to 7.6 nm and reaches 9.3 MV/cm at 2.5 nm.     

Photochemical Synthesis and Characterization of 8,9-Dihydroacenaphtho-[1,2-b][1,4]Dioxins

The orange-red 8,9-dihydroacenaphtho[1,2-b] [1,4]dioxins were synthesized by the photo-Diels-Alder reaction of acenaphthenequinone with the corresponding alkenes. The products were characterized by spectroscopic and X-ray methods.     

FTIR study of the surface properties and tribological behaviors of plasma-modified UHMWPE and zirconia

Zirconia and ultra-high molecular weight polyethylene (UHMWPE) are common materials for artificial joints. However, the failure of artificial joints is mainly caused by the wear of UHMWPE. Therefore, the development of effective measures to enhance the service life of UHMWPE is one of the most important facets of research on total joint replacement. The purpose of this study is to use an atmospheric-pressure plasma system to modify zirconia and UHMPWE surfaces, which is expected to increase the adsorption of joint-lubricating fluids, thus reducing the abrasion and wear of UHMWPE (73% improvement). Surface modification experiments were carried out using an atmospheric-pressure plasma system, while fourier transform infrared spectroscopy was used to characterize the surfaces treated with atmospheric-pressure plasma. The results of water contact angle tests indicated that the plasma-treated material surfaces exhibited excellent hydrophilicity (70% improvement). In addition, the treatment of materials with atmospheric plasma was confirmed to increase the adsorption of lubricating fluid and reduce wear, thus extending the service life of UHMWPE.     

Oxidation of Polyisoprene Popcorn Polymer. III. Further Studies on Water and Carbon Dioxide Production

The volatile products resulting from polyisoprene popcorn polymer oxidation were analyzed quantitatively for carbon dioxide and water, and semiquantitatively for formaldehyde. The production of these three products was a linear function of the amount of oxygen consumed in the reaction. For every mole of oxygen reacted, 0.098 mole of water, 0.038 mole of carbon dioxide, and > 0.016 mole of formaldehyde were formed. Twenty-four products were detected after extensive oxidation; the major ones being water, carbon dioxide, formaldehyde, formic acid, 2,5-hexanedione, and acetic acid. No levulin-aldehyde was identified in the products. A tentative oxidation mechanism is discussed.     

Cellulose nanocrystal extraction from rice straw using a chlorine-free bleaching process

Cellulose nanocrystals (CNCs) have attracted tremendous attention because of their excellent chemical and physical properties and due to their renewability and sustainability. This material can be extracted from agricultural by-products such as rice straw, banana tree, or bagasse. Rice straw was selected as the raw material in this study. Initially, a large amount of lignin must be removed by an alkaline process to obtain a slurry. Thereafter, a green bleaching process can be used to remove the remaining lignin in the slurry. An UV-emitting diode with 365 nm wavelength assisted the oxidation reaction of the H₂O₂ solution without the use of chlorine-containing chemical bleach. The reaction required only 2.5 h to obtain high-purity cellulose and successfully enhanced the yield. Transmission electron microscopy images showed that the CNCs from rice straw were?~?100 nm long and 10–15 nm wide. The crystalline index and degradation temperature of CNCs were 83.8% and 257 °C, respectively.

     

FTIR and Raman study of the structural properties and tribological characteristics of collagen

Optical and Quantum Electronics - In the present paper, we propose a compact composite wedge interference structure by combining wedges with different geometry. We use interferential wedges with...     

The Anomalous Emission Characteristics of the Cyalume Fluorescer: 9,10-Bis (Phenylethynyl) Anthracene

A fancy emission behavior was found in the light carrier of the commercial Cyalume light stick, 9,10-bis (phenylethynyl) anthracene (BPEA). The yellowish-orange emission is noted from BPEA in methylcyclohexane matrix. Nitrogen laser time-resolved spectroscopy and excitation luminescene studies of BPEA in methylcyclohexane showed that the different emission behavior is probably due to the different conformation of the ground state of the BPEA in solid and in solution.