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A significant number of X-ray binaries are now known to exhibit long-term periodicities on timescales of ~10 - 100 days. Several physical mechanisms have been proposed that give rise to such periodicities, one of which is radiation-driven warping and precession of the accretion disk. Recent theoretical work predicts the stability to disk warping as a, function of the mass ratio, binary radius, viscosity and accretion efficiency. We investigate the stability of the superorbital periodicities in the neutron star X-ray binaries Cyg X-2, LMC X-4, SMC X-l and Her X-l, and thereby confront stability predictions with observation. We find that the period and nature of the superorbital variations in these sources is consistent with the predictions of warping theory.
Increasingly, evidence suggests a role for polyphenols in blood glucose control. The objective of this systematic review was to evaluate the effect of polyphenol-rich sources in combination with carbohydrate sources on resulting postprandial glycaemic and insulin responses. A literature search was conducted using Medline, CINHAL and Web of Science databases. Selected studies included randomised controlled trials in which the association of polyphenol-containing food or beverage consumption with a carbohydrate source and effect on acute postprandial glycaemia and/or insulin was reported. A total of thirteen full articles were included in the review. Polyphenol sources included coffee, black tea, fruit juice, plant extracts, berries and different rye breads, and carbohydrate sources included bread, pancakes and simple sugars such as sucrose, glucose and fructose. Although glycaemic and insulin responses differed depending on the polyphenol–carbohydrate combination, overall, polyphenol sources were shown to reduce the peak and early-phase glycaemic response and maintain the glycaemic response in the later stages of digestion. To a lesser extent, polyphenol sources were also shown to reduce peak insulin response and sustain the insulin response, especially when consumed with bread. This review supports epidemiological data suggesting that polyphenols in foods and beverages may have a beneficial effect on reducing the risk of type 2 diabetes. However, the extent of this effect is variable depending on the polyphenol and carbohydrate source.
We present infrared spectra of 4 Be/X-ray binaries in the K band, and 4 spectra in the J, H and K bands of 2 more sources. The HI IR emission lines are useful determinators of the conditions in the inner regions of the circumstellar disk about the Be star, due to optical depth effects. These are preliminary results, and hope to be followed up by high resolution echelle spectra, where we wish to estimate the velocity field, temperature and density structure of the circumstellar material.
The Be massive X-ray binary LSI+61°303 is a 26.5 days periodic radiosource (Taylor & Gregory, 1984), exhibiting radio outbursts maxima between phases 0.6–0.8. Evidence of a photometric period of similar value has also been reported (Paredes & Figueras, 1986; Mendelson & Mazeh, 1989). The previous spectroscopic radial velocity observations of Hutchings & Crampton (1981) are in agreement with the radio period, and give support to the presence of a companion. We present new optical and infrared photometric observations and high resolution Hα spectra of LSI+61°303.
We have developed a new silicon nitride (SiNx) multilayer barrier film by a plasma-enhanced chemical vapor deposition (CVD) for a flexible organic light emitting diode (OLED), which consists of SiNx films in two different deposition conditions, that is, a transparent SiNx layer (tr-SiNx) deposited with NH3 gas and an ultra-thin SiNx layer (cap-SiNx) deposited without NH3 gas, which caps over the former layer. This barrier film is expected to exhibit high durability under high temperature and high humidity conditions even at high deposition rate over 100 nm / minute, because the transparent SiNx layer, that is easily oxidized under such conditions, is protected by the cap-SiNx layer and the interface between them, and also show good transparency, because the opaque cap-SiNx layer is enough thin to be almost transparent to visible light. Thus, the multi-layer SiNx barrier film indicates the specific features as a high barrier performance, high transparency, and high productivity, and makes it possible to apply flexible OLED displays to automobile use.
We report on the MOCVD growth of GaAs on patterned Si utilizing the Aspect Ratio Trapping (ART) method to reduce threading dislocations resulting from lattice mismatch. Defect-free GaAs was obtained from growth in sub-micron trenches formed in SiO2 on Si (001) substrates. Material quality has been characterized by cross-sectional and plan-view TEM and XRD. It was found that when growing GaAs above the trenched region, coalescence-induced threading dislocations (TDs) and planar defects were introduced at the coalescence junction interfaces. These defects were found to be unrelated to the misfit defects (MDs) on GaAs/Si interface that originated during initial epitaxial growth. Causes of coalescence defect formation were experimentally investigated by employing a two-step defect reduction scheme. It is concluded that by further optimizing growth conditions during coalesce layer growth, low defect-density GaAs material can be obtained on Si substrate.
Manufacturing transistors on thin flexible polymer foils is challenging and differs from standard Si processing due to the dimensional instability of the substrate influenced by moisture uptake, temperature and handling. A thorough analysis of material properties of the tested foil was performed to understand its behavior during lithography and subsequently to improve the processing. Imaging experiments on 100 µm polyethylene naphthalate (PEN) foils were performed with a PAS 5500/100D ASML step and repeat I-line (365 nm) system equipped with reticles having features of several microns and also sub-micrometer dimensions. A foil lamination process was developed to improve the dimensional stability during processing and to achieve a good surface flatness crucial for sub-micrometer imaging. The optimum process window for sub-micrometer critical dimensions was determined by performing a Focus Exposure Matrix (FEM) experiment in which the energy and focus were increased stepwise. The optimum imaging conditions were derived from SEM analysis. The results indicated a reproducible and good patterning accuracy for making patterns below 1µm size.
There is a growing need for optical fiber coatings that can sustain higher temperatures than present materials permit. To date, polyimides are used predominantly but they generally are difficult to process and usually require multiple depositions to achieve the desired film thickness. Perfluorocyclobutyl (PFCB) aryl ether polymers have demonstrated much success as processable and amorphous fluoropolymers, with particular emphasis on high performance optical applications. This work discusses recent efforts into perfluorocyclobutyl aryl ether polymer-based optical fiber coatings. A series of silica-based optical fibers were drawn with differing PFCB polymer coatings compositions and molecular weights on a Heathway draw tower. Results include a more than doubled usage temperature of coating (decomposition temperatures (Td) in nitrogen and air were above 450 °C) without affecting fiber mechanical properties and comparable isothermal stability to conventional coatings, except with a >150 °C higher temperature. Preliminary results of the first successful coating of optical fibers by PFCB polymers will be presented herein, as well as future endeavors.