Glycidyl methacrylate (GMA) functionalized acrylonitrile–butadiene–styrene (ABS) copolymers have been prepared via an emulsion polymerization process. These functionalized ABS copolymers (ABS-
g-GMA) ...were blended with poly(butylene terephthalate) (PBT). DMA result showed PBT was partially miscible with ABS and ABS-
g-GMA, and DSC test further identified the introduction of GMA improved miscibility between PBT and ABS. Scanning electron microscopy (SEM) displayed a very good dispersion of ABS-
g-GMA particles in the PBT matrix compared with the PBT/ABS blend when the content of GMA in PBT/ABS-
g-GMA blends was relatively low (<8
wt% in ABS-
g-GMA). The improvement of the disperse phase morphology was due to interfacial reactions between PBT chains end and epoxy groups of GMA, resulting in the formation of PBT-
co-ABS copolymer. However, a coarse, non-spherical phase morphology was obtained when the disperse phase contained a high GMA content (≥8
wt%) because of cross-linking reaction between the functional groups of PBT and GMA. Rheological measurements further identified the reactions between PBT and GMA. Mechanical tests showed the presence of only a small amount of GMA (1
wt%) within the disperse phase was sufficient to induce a pronounced improvement of the impact and tensile properties of PBT blends. SEM results showed shear yielding of PBT matrix and cavitation of rubber particles were the major toughening mechanisms.
The pulsating DA white dwarfs (ZZ Ceti stars) are g-mode non-radial pulsators. Asteroseismology provides strong constraints on their global parameters and internal structure. Since all the DA white ...dwarfs falling in the ZZ Ceti instability strip do pulsate, the internal structure derived from asteroseismology brings knowledge for the DA white dwarfs as a whole group. HS 0507+0434B is one of the ZZ Ceti stars which lies approximately in the middle of the instability strip for which we have undertaken a detailed asteroseismological study. We carried out multisite observation campaigns in 2007 and from 2009 December to 2010 January. In total, 206 h of photometric time series have been collected. They have been analysed by means of Fourier analysis and simultaneous multifrequency sine wave fitting. In total, 39 frequency values are resolved including six triplets and a number of linear combinations. We identify the triplets as = 1 g modes split by rotation. We derived the period spacing, the rotational splitting and the rotation rate. From the comparison of the observed periods with the theoretical periods of a series of models, we estimate the fundamental parameters of the star: its total mass M
*/M = 0.675, its luminosity L/L = 3.5 × 10−3, and its hydrogen mass fraction M
H/M
* = 10−8.5.
The Isochronous Mass Spectrometry (IMS) is a powerful technique developed in heavy-ion storage rings for measuring masses of very short-lived exotic nuclei. The IMS is based on the isochronous ...setting of the ring. One of the main parameters of this setting is the transition energy γt. It has been a challenge to determine the γt and especially to monitor the variation of γt during experiments. In this paper we introduce a method to measure the γt online during IMS experiments by using the acquired experimental data. Furthermore, since the storage ring has (in our context) a relatively large momentum acceptance, the variation of the γt across the ring acceptance is a source of systematic uncertainty of measured masses. With the installation of two time-of-flight (TOF) detectors, the velocity of each stored ion and its revolution time are simultaneously available for the analysis. These quantities enabled us to determine the γt as a function of orbital length in the ring. The presented method is especially important for future IMS experiments planned at the new-generation storage ring facilities FAIR in Germany and HIAF in China.
► Non-polar growth. ► Large red shift of the optical band gap is related to the decreasing of carrier concentration and incorporation of charged defects. ► The three main emission peaks may ...constitute white light. ► Non-polar growth of ZnO has improved greatly the luminous efficiency.
Pure zinc oxide (ZnO) and lead (Pb) doped zinc oxide (ZnO:Pb) films with different Pb doping concentrations were deposited on glass substrate by using radio frequency reactive magnetron sputtering technique. X-ray diffraction spectroscopy measurements showed that all samples with the (100) preferential orientation were growth of the non-polar. The results of X-ray photoelectron spectroscopy analysis suggested that the Pb ions were successfully doped into lattice of ZnO and the valence of Pb in the ZnO films was a mixed state of +2 and +4. Optical band gaps of the ZnO:Pb were 3.24, 2.92, 2.86 and 2.74eV with the increase of Pb doping concentration, it could attribute this red shift phenomenon to the decrease of carrier concentration. Photoluminescence measurements showed that a broad emission band including the two blue emission peaks are about at 437nm and 470nm, one green and red emission peaks are about at 510nm and 710nm, which may compound white light. Moreover, growth of non-polar ZnO enhanced enormously the luminous efficiency of photoluminescence in our experiment. The current–voltage measurements between two surface electrodes showed the increase in resistance with increase of Pb doping concentration.
The effects of exogenous 24-epibrassinolide (EBR) on the growth, oxidative damage, antioxidant system and ion contents in eggplant (
Solanum melongena
L.) seedlings under salt stress were ...investigated. Eggplant seedlings were exposed to 90 mM NaCl with 0, 0.025, 0.05, 0.10 and 0.20 mg dm
−3
EBR for 10 d. EBR, especially at concentration 0.05 mg dm
−3
, alleviated growth suppression caused by NaCl stress, decreased electrolyte leakage, superoxide production and content of malondialdehyde and H
2
O
2
in NaCl-treated plants. EBR also increased activities of superoxide dismutase, guaiacol peroxidase, catalase and ascorbate peroxidase and the contents of ascorbic acid and reduced glutathione. Furthermore, we also found that Na
+
, Cl
−
contents were decreased, K
+
, Ca
2+
contents and K
+
/Na
+
, Ca
2+
/Na
+
ratios were increased in the presence of EBR under salt stress.
Interface is an important structure in the materials, some rather peculiar physical phenomena can occur at the interface under the application of the exterior physical field. Especially, the grain ...boundary, phase interface and layer interface are significant factors for improving the thermal insulation behavior of thermal barrier coatings (TBCs). In this paper, finite element method was employed to simulate the heat transfer behavior of TBCs with different interfacial characteristic based on several different interfacial thermal resistance (ITR) models. The simulation results indicate that the heat flux around the interface has exhibited fantastic changing characteristic, the thermal insulation effect of TBCs would be enhanced with the area of the interface increasing. The interface roughness (amplitude) also has a very important effect on the effective thermal conductivity of the as-sprayed TBCs. A novel method, Computational Micromechanics Method (CMM), was utilized to depict the heat transfer behavior of actual coatings with irregular inner interface. The “thermal rectification” mechanism of heat diffusion around the interface make that the heat flux which passes through the interface has exhibited different flow characteristic compared with the positions without interface. In addition, some simple experiments have further verified the existence of the ITR between the bond-coat and top-coat. The investigation results will also provide us a powerful guide to design coating with high thermal insulation property using the physical theory and mechanism of the ITR.
Isochronous mass spectrometry has been applied to neutron-deficient Ni-58 projectile fragments at the HIRFL-CSR facility in Lanzhou, China. Masses of a series of short-lived T-z = -3/2 nuclides ...including Ti-41, Cr-45, Fe-49, and Ni-53 have been measured with a precision of 20-40 keV. The new data enable us to test for the first time the isobaric multiplet mass equation (IMME) in f p-shell nuclei. We observe that the IMME is inconsistent with the generally accepted quadratic form for the A = 53, T = 3/2 quartet. We perform full space shell model calculations and compare them with the new experimental results.
The cross section of the process e+e−→K+K− is measured at a number of center-of-mass energies s from 2.00 to 3.08 GeV with the BESIII detector at the Beijing Electron Positron Collider (BEPCII). The ...results provide the best precision achieved so far. A resonant structure around 2.2 GeV is observed in the cross section line shape. A Breit-Wigner fit yields a mass of M=2239.2±7.1±11.3 MeV/c2 and a width of Γ=139.8±12.3±20.6 MeV, where the first uncertainties are statistical and the second ones are systematic. In addition, the timelike electromagnetic form factor of the kaon is determined at the individual center-of-mass energy points.
•ZnO films were deposited on PS substrates by RF magnetron sputtering.•Post-annealing has effect on the microstructure and optical properties of ZnO/PS films.•The intensity of PL peak has obviously ...increased with the annealing temperature increasing.•ZnO films formed a broad PL band including the violet, blue, green and red–orange emission.
In this study, porous silicon (PS) templates were formed by electrochemical anodization on p-type (100) silicon wafer and ZnO films were deposited on PS substrates using radio frequency reactive magnetron sputtering technique. The effects of annealing temperature on the microstructure and optical properties of the ZnO/PS nanocomposite films were systematically investigated by X-ray diffraction (XRD), UV–Visible spectroscopy and fluorescence spectrophotometry. XRD results indicated that all ZnO films were polycrystalline in nature with a hexagonal wurtzite structure and the (0002) oriented ZnO films deposited on PS substrates had the best crystal quality under annealing at 700°C. It was demonstrated that the optical band edge shifted to longer wavelength as the annealing temperature shifted from room temperature (RT) to 700°C due to the quantum confinement effect. Furthermore, the optical band gaps calculated based on the quantum confinement model were in good agreement with the experimental values. Photoluminescence (PL) measurements at RT revealed that ZnO/PS films formed a broad PL band including the violet, blue and green emissions from ZnO and red–orange emission from the PS. The mechanism and interpretation of broadband PL of the films were discussed in detail.
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