Papers by Keyword: Light Scattering

Abstract: Mesoporous SiO₂@TiO₂ (MP-SiO₂@TiO₂) core-shell particles were fabricated using mesoporous SiO₂ particles as a template in order to improve scattering performance and dye adsorption performance of the photoanode of dye-sensitized solar cells (DSSCs). They were used to make the scattering layer of the photoanode. Commercially available submicron TiO₂ particles G1 that have the same particle size as the fabricated SiO₂@TiO₂ particles were also used to make the scattering layer to compare the photoelectric properties of the DSSC. The DSSC with the photoanode without a scattering layer generated a conversion efficiency of 1.54 %. By introducing a scattering layer composed of MP-SiO₂@TiO₂ to the photoanode, the conversion efficiency was improved to 2.82 %. In addition, the DSSC with the scattering layer composed of MP-SiO₂@TiO₂ generated higher conversion efficiency than that of the DSSC with the scattering layer composed of G1 (2.35 %). From these results, MP-SiO₂@TiO₂ particles produced a high performance as scatterers in the photoanode of DSSCs.

Abstract: In this research, we detailed how the following factors affect the scattering of light by nanofluids: (1) nanoparticle sizes, (2) volume fraction of nanoparticles, and (3) nanoparticle materials. Mie theory was used to calculate the radiative properties of the nanofluids. The radiative properties were then applied into the Radiative Transfer Equation (RTE) to solve for the transmittance and reflectance of light through the nanofluids. The RTE was solved using the Monte Carlo method. Results showed that when the size of nanoparticles and the volume fraction increase, absorption and scattering coefficients increase as well. For silver nanofluids, absorption and scattering coefficients decrease beyond nanoparticle size of about 50 nm. Transmittance of light decreased when nanoparticle sizes increased. When comparing between TiO₂, Ag, and SiO₂ nanofluids, Ag nanofluids exhibit the highest light absorption followed by TiO₂ and SiO₂.

Abstract: PLZT (X/70/30) ceramics with different La contents (X=7.45, 7.54, 7.63 mole%) were fabricated by hot-press sintering techniques. The effects of annealing on ferroelectric, optical and electrically controlled light scattering properties of PLZT transparent ceramics were examined and analyzed. The XRD patterns indicated that all the samples were crystallized into a pure perovskite phase without the second phase. The SEM exhibited fully dense, uniform microstructures with well-developed grains. The annealing treatment weakened the degree of squareness of the ferroelectric hysteresis loop, and even the anti-ferroelectric phase occurred as the La content increasing to X=7.63. The remnant polarization (Pr) and coercive electric field (Ec) decreased with the annealing treatment for all samples. The slow annealing treatment resulted in the lager increase of both transmittance and contrast ratio than those of the rapid annealing treatment at λ=632.8nm. The electrically controlled light scattering properties were obviously enhanced by the annealing treatment. Especially, the PLZT (7.63/70/30) ceramics exhibited the different electrically controlled light scattering performance which indicated it could hold high transmittance and symmetry in a wide electric field range with the slow annealing treatment.

Abstract: The narrow particle size distribution of poly (vinyl silicone) microspheres were prepared by the hydrolysis-polycondensation method with vinyl silane (VTMS) as raw materials. And the influences of pH value, oil/water ratio on the morphology, particle size and distribution of the microspheres were studied. The results shows that the particle size of microspheres decrease with the increasing of the PH value of polymerization, and the particle size has no specific linear relationship with the PH value of hydrolysis reaction, while the oil-water ratio is smaller, single particle size distribution is more narrow, more uniform distribution.

Abstract: The optical properties of colloidal solutions of nanosized magnetite particles in kerosene were studied by optical methods (birefringence and light scattering). The data on the birefringence kinetics in nonstationary magnetic fields is used to determine the size distribution of magnetite particles and aggregates. It is shown that the particle size distribution essentially depends on the type of magnetic moments of the particles and aggregates. Static and dynamic light scattering experiments confirm the conclusion about the existence of a significant fraction of nanoparticles in the form of aggregates with sizes of several tens of nanometers.

Abstract: In previous studies [1, , we have presented a detailed formulation of a macroscopic analytical model of the optical propagation of laser beams in the case of unidirectional thermoplastic composites materials. This analytical model presented a first step which concerns the estimation of the laser beam intensity at the welding interface. It describes the laser light path in scattering transparent composites (first component) by introducing light scattering ratio and scattering standard deviation. The absorption was assumed to be negligible in regard to the scattering effect. In this current paper, in order to describe completely the laser welding process in composite materials, we introduce the absorption phenomenon in the model, in the absorbing material (second component), in order to determine the radiative heat source generated at the welding interface. Finally, we will be able to perform a three dimensional temperature field calculation using a commercial FEM software. In laser welding process, the temperature distribution inside the irradiated materials is essential in order to optimize the process. Experimental measurements will be performed in order to valid the analytical model.

Abstract: In order to settle the influence of measuring results of cells with its shape-variety in the examination of biological cell, MCEM (modify co-central ellipse model) is adopted based on the theories of Rayleigh-Debye-Gans, and the changing tendency of scattering phase function of nucleated cells with different body factor, nuclear size and shooting angle are studied. These provide a useful theory foundation for improving the measurement and distinguishing of biological cell.

Abstract: An experimental apparatus for the analysis of biological cells light scattering in liquid suspensions has been presented. Characterization is based on the scattering of a monochromatic laser beam by particles [which can be inorganic, organic, or biological (such as animal cells and bacteria)] and on the strong relation between the light-scattering pattern and the morphology and refractive index of the particles. In order to study light scattering in biological cells close to the actual situation, we focus on non-spherical particles in the cell-culture medium. Finally, we demonstrate the light scattering results of bovine kidney cells suspended in the cell-culture medium, and compares then with the simulated results.

Abstract: In order to restore the image in dust environment, a method was proposed to restore the images in dust environment based on a single still image. Firstly, an image degradation model considering multiple scattering factors caused by dust was built using the first-order multiple scattering methods. Then, a new geometric depth model of single image was presented. This model utilized depth map of a dust image to improve usual geometric depth model. According to the new model the every distance of the objects in dust environment was able to acquire from a single still image. Finally, an image in dust environment could be restored according to the relationship between the dark channel prior model and the distance information which was calculated by the geometric depth model. The experimental results have shown that the method enhanced luminance and contrast. The method provided a foundation for target recognition in the dust environments.

Abstract: The phase images of cells and tissues are of great importance for obtaining their morphological and dynamics information. However, because of the uniform optical path-length of a light field passing through the inhomogeneous cells whose nuclei’ shape and structure are different but with equivalent physical thickness, we can not identify their subgroup just from their phase images, since their wrapped phase images have similar shape. Thus we put out a new idea that uses their scattering distributions as a auxiliary criterion for identifying cells with different nuclei structure. We built the ellipsoidal models to denote the cells’ external shape and placed three kinds of nuclei, such as hexahedron, cylinder and spheroid, into the center of ellipsoids to compose nucleated leucocytes. Employing the VirtualLab software to carry out the simulations, we first prove that, for cells with different nuclei structures, their wrapped phase distributions indeed have similar shape. Then after analyzing the results of scattering simulations, we obtain some important scattering characteristics related with their different nuclei’ shape and structures which are very useful for helping us to identify blood cells’ subgroup and can also provide good guidance for experimental research on inhomogeneous cells.