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The temperature dependent out-diffusion of dimethyl sulfoxide (DMSO) from CH3NH3PbI3 precursor layers was investigated by analyzing the S/Pb molar ratio in the layers by high-resolution continuum s...

Pavement subjected to the traffic load above shakedown limit is predicted to exhibit accumulated plastic strains that eventually lead to failure within the pavement system. Shakedown theory is a valid approach to estimating the critical shakedown load level. In this study, a dynamic shakedown method for computing the shakedown limit of pavement is presented based on the lower-bound theorem of shakedown. To this end, a combined Finite element-Infinite element (FE-IE) method is utilized to calculate the dynamic elastic stress field due to rolling and sliding contact between wheel and pavement surface considering the effect of moving speed. The rolling and sliding contact is approximated by a moving Hertz distribution load, which is performed through moving vertical and horizontal body forces simultaneously modeled by thin-layered element above the pavement surface. Shakedown limits for both uniform and two-layered pavement system at various moving speeds have been investigated, respectively. It is found that the shakedown limit decreases with the increasing moving speed and then turns to increase when the moving speed exceeds the Rayleigh wave speed. This dynamic effect is more profound when the horizontal force is small. The influence of horizontal force on shakedown limit at various moving speed is also discussed. Eventually, the impact of frictional coefficient and material properties on shakedown limit for two-layered pavement is also investigated as can then be applied to the optimal pavement design.

The time-dependent inhomogeneous temperature distribution in steel plates during the cooling increases thermal strains which, in turn, generate plastification and thus residual stresses. Moreover, phase transformation from the parent austenite phases into a product phase typically entails not only metallurgical strains but also accounts for transformation induced plasticity (TRIP), which again generates transformation related residual stresses. A unified material model that consisting of all relevant contributions to the total strain rate, i.e., elastic, plastic, thermal, metallurgical and TRIP strain contributions could be built in this paper. Transformation also released a significant amount of latent heat which naturally affected the temperature field that governed the evolution of the product phase. For the latter kinetic relationship about difference between diffusive and displacive transformation mechanisms depending on the local cooling rate is presented. Using an Avrami-like approach, the transformation kinetics is set up especially for complex cooling histories. The material model simulated the evolution of the residual stresses as well as the warping of the steel plates after completely cooling to room temperature.

Core-double shell structure poly(vinyl acetate-butyl acrylate) emulsion was prepared by semicontinuous emulsion polymerization, and the effects of ethyleneglycol dimethacrylate crosslinker (EGDMA) on the emulsion particle structure and film performance were studied systematically. The emulsion particles' structure was characterized by transmission electron microscopy and Fourier transform infrared spectroscopy, and the particle size and distribution were characterized by Zeta potential—particle analyzer, as well as analysis of the film mechanical properties, water resistance, thermal properties, and so on. The results show that, when 0.1 and 0.5% EGDMA were added to the inner-shell and outer-shell reaction stage under the core-double shell P(VAc-BA) emulsion preparation process, respectively, it led to a more clear core-double shell structure and a larger particle size (about 500–800 nm) of emulsion particles, and the comprehensive performance of the P(VAc-BA) emulsion showed better. This work provided some insight into modifying the surface properties of the emulsion particles, which may expand the application field of the emulsion. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41899.

We observe the photorefractivity without bias voltage or prepoling in a bifunctional photorefractive polymer. The maximum two-beam coupling gain is measured to be 126 cm−1 at zero bias voltage. The sample is considered to be poled by the photoinduced longitudinal electric field, which is formed due to the light intensity gradient along the light path. The expression of the electric field was deduced. The energy transfer direction between two writing beams and light intensity dependence of the two-beam coupling gain coefficient is predicted to be consistent with the experimental results. Furthermore, the dependence of the two-beam coupling gain coefficient on external applied electrical field is measured and this experiment verifies the existence of the photoinduced longitudinal electric field.

Photorefractive (PR) composites based on poly(N-vinylcarbozale) and azobenzene have been fabricated. Two-beam-coupling and four-wave-mixing phenomena were observed in the absence of an external electric field or prepoling. The maximum two-beam-coupling gain coefficient and the refractive index modulation were measured to be 79 cm−1 and 2.2×10−4 respectively. The all-optical-PR phenomenon is explained based on the photoassisted poling of the azo dye by the synergism of the photoisomerization and the longitudinal electric field due to longitudinal intensity gradient of writing light beams. The bi-hole-transporting system provides more charge-carrier traps resulting in improvement of PR performance.

It is discovered experimentally that, when placing a plate of dye BDN in a ring YAG laser cavity, the dye shows asymmetric control actions on the clockwise and counter-clockwise travelling waves. Unidirectional dye Q-switched operation is realized in a ring cavity based on this property without the use of Faraday rotator, polarizer and half-wave plate. A simplified theoretical analysis of this phenomenon is presented.

A novel full-functional photorefractive small molecular material, (9-ethyl-9H-carbazol-3-ylmethylene)-(4-nitro-phenyl)-amine (ECYENPA), was synthesized and its photorefractivity was studied by two-beam coupling experiments at a wavelength of 632.8 nm. The glass transition temperature of ECYENPA, as low as −5 degrees C, results in the chromophore being orientated easily at room temperature. High two-beam coupling coefficient was obtained to be 232 cm−1 at an electric field of 44.6 V/μm.

The parallel direct method of direct numerical simulation (PDM-DNS) for Rayleigh-Bénard (RB) convection is used in this paper. The differences and similarities in flow characteristic between two-dimensional (2D) and three-dimensional (3D) turbulent RB convection are studied using mean field for Ra=109, 1010, 5×1010, and Pr=4.3. Each of 2D and 3D cases has a large-scale circulation and corner rolls. The shape of large-scale circulation becomes round and the size of corner roll turns small as Ra increases. In 2D RB convection, there are four corner vortices at the corner of the square cavity and a stable large-scale circulation which is elliptical. For spanwise averaged 3D RB convection with two corner vortices, large-scale circulation reveals spindle shape. Due to the characteristic of the corner roll, the region plume dominating is wider in 2D RB convection than in the spanwise-averaged 3D case. Further, the Ra-dependence of thermal boundary layer properties is also studied. The thermal boundary layer thickness is scaled with Ra and the scaling exponents of λθ with Ra in the 2D and 3D cases are very similar.

Generation of an up to 1.5-W single-frequency and a 650-mW frequency-stabilized second harmonic at 1.06 µm has been demonstrated in a cw ring Nd:YAG laser with a pair of properly oriented KTP crystals in which the walk off between the intracavity modes has been eliminated. The frequency stability is better than 5 MHz for the second-harmonic output level of 650 mW. The fluctuation of power is less than 4%. PACS: 42.60. By. 42.65 Ky.

Based on collisional and radiative processes occurring in the inductively coupled plasma, non-Boltzmann energy level distributions of argon atoms are calculated under various conditions, by using ideal gas law and solving rate equations.

Transparent display is one of the main technologies in next-generation displays, especially for augmented reality applications. An aperture structure is attached on each display pixel to partition them into transparent and black regions. However, diffraction blurs caused by the aperture structure typically degrade the transparent image when the light from a background object passes through finite aperture window. In this paper, the diffraction effect of an active-matrix organic light-emitting diode display (AMOLED) is studied. Several aperture structures have been proposed and implemented. Based on theoretical analysis and simulation, the appropriate aperture structure will effectively reduce the blur. The analysis data are also consistent with the experimental results. Compared with the various transparent aperture structure on AMOLED, diffraction width (zero energy position of diffraction pattern) of the optimize aperture structure can be reduced 63% and 31% in the x and y directions in CASE 3. Associated with a lenticular lens on the aperture structure, the improvement could reach to 77% and 54% of diffraction width in the x and y directions. Modulation transfer function and practical images are provided to evaluate the improvement of image blurs.

A spectrographic survey of the impurity lines was made on the CT-6B Tokamak with I metre grazing incidence spectrograph. The observed wavelength ranges were from 1580 to 550 ? and from 460 to 43 ?, using 300 lines/mm and 1200 lines/mm gratings respecrively. The survey revealed that the main impurities in CT-6B Tokamak plasma are Mo for high Z impurities and C, N, O for low Z impurities. There are a large number of OV and OVI lines with intense emission. We also observed MoVIIl resonance lines 234.314 ?, 235.510 ? and 237.215 ?. The shortest observed wavelengths are the second order of OVII lines 21.6020 ? and 21804 ?. The first order of these two lines situate beyond the film and can not be recorded. According tc the features of the spectra and the ionization potentials of OV, OVI as well as MoVII, the average electron temperature for CT-6B Tokamak is estimated to be about 140 eV. Oxygen is the main impurity in CT-6B Tokamak, and its lines emission is the main portion of energy loss in CT-6B Tokamak. Lines of the main components of the vacuum-vessel material such as Fe, Cr, Ni and Ti have not been found.

Collision cross sections as well as electrical conductivity, thermal conductivity, diffusion coefficients and viscosity coefficients of an inductively coupled argon plasma are calculated. The results indicate that thermal conduction process plays an important role in energy transfer, while ambipolar diffusion leads to a much higher electron density in the cool plasma regions as compared with the value predicted by local thermal equilibrium. More significantly, both three body recombination and superelastic collision give rise to the creation of a large number of energetic electrons in the cool plasma regions. Such a deviation of electron velocity distribution from a Maxwellian may have a special significance for excitation mechanism of the plasma used as an emission spectroscopic source.

A novel natural rubber/silica (NR/SiO2) nanocomposite is developed by combining self-assembly and latex-compounding techniques. The results show that the SiO2 nanoparticles are homogenously distributed throughout NR matrix as nano-clusters with an average size ranged from 60 to 150 nm when the SiO2 loading is less than 6.5 wt%. At low SiO2 contents (⩽4.0 wt%), the NR latex (NRL) and SiO2 particles are assembled as a core-shell structure by employing poly (diallyldimethylammonium chloride) (PDDA) as an inter-medium, and only primary aggregations of SiO2 are observed. When more SiO2 is loaded, secondary aggregations of SiO2 nanoparticles are gradually generated, and the size of SiO2 cluster dramatically increases. The thermal/thermooxidative resistance and mechanical properties of NR/SiO2 nanocomposites are compared to the NR host. The nanocomposites, particularly when the SiO2 nanoparticles are uniformly dispersed, possess significantly enhanced thermal resistance and mechanical properties, which are strongly depended on the morphology of nanocomposites. The NR/SiO2 has great potential to manufacture medical protective products with high performances.