Papers by Keyword: Scattering

Abstract: The turbidity of water is one of primary indexes for water quality measurement. Existing main methods for measuring turbidity include scattering method and transmission method. The scattering method is effective for the measurement of low turbidity. Conversely, the transmission method is only suitable for the measurement of high turbidity. In this work, scattering method, transmission method and ratio method are integrated, an on-line turbidity sensor is presented. According to ISO7027 international standards, the sensor’s layout of optical path structure is realized. The detectors are laid in the direction of light source 0 degrees and 90 degrees respectively. Furthermore, the influences of temperature and light on the sensor precision are considered. Least squares support vector machine is introduced to model the turbidity sensor. The experimental results show that this method has much higher precision than the classic methods.

Abstract: We fabricated silver nanoprisms (AgNPs) on ITO by immersing ITO substrates in AgNPs solution for a series of immersion times. The amount of adsorbed AgNPs increased with immersion time. The AgNPs showed plasmonic absorption in the range of 400 – 600 nm and were used in organic solar cells (OSCs). The device performance was the best when the immersion time was 30 min, corresponding to AgNPs coverage of 68%. Under this condition, the device showed short-circuit current density (J_SC) of 10.10 mA cm^-2 (18% improved), and power conversion efficiency (PCE) of 3.88% (23% improved).

Abstract: The scattering of time harmonic SH waves by arbitrary positions of circular cylindrical cavity is studied in continuous, homogeneous, isotropic, elastic strip region. In this paper, the completely analytical expression of total wave field is explicitly presented and the dynamic stress distribution is symbolically visualized in the strip region. The total wave field is divided into four sub wave fields, incident wave field and scattering wave field by the upper bound, the lower bound and the cylindrical bound, on big arc supposition. Specific wave functions are employed for each wave field expansion in series, such as circular cylindrical functions, respectively. Corresponding infinite linear algebraic equations are constructed by means of solving coefficients of Fourier series expansion on each sub wave field. Coefficients of cylindrical function expansion of each sub wave field are determined by truncated equations, which are reduced number of coefficients on pre-given computational accuracy. Numerical results graphically describe the dynamic stress concentration factor around the circumference of the cavity and the normalized dynamic stress along the cross section directly above the cavity.

Abstract: To detect black smokers is the hot topic nowadays. The arounding mineral resources is the human wealth, which has extensive researchful significance. The submarine volcanic eruptions can cause thermal plume and the air curtain group. This paper study the acoustic characteristics of the air bubble, and built the simulation model of air curtain group. With pool for experimental platform, we make the formation process of the air curtain, and experiment with acoustic method to detect air curtain. After processing the data, analyze its fluctuation rate to judge the existence of air curtain. To verify feasibility of this method.

Abstract: Methodology of the way of supposed sound levels calculations in closed objects areas from the sound sources is based on assumptions, that the propagation of sound is dominant. In many cases the acoustic properties of space of sound propagation have great importance. We have to take in the consideration - the size and cross-section areas of dispersion bodies, their sound absorption coefficient; - shape of area and boundary areas absorption; - position of concerning point in relation to the source position in space; - noise of technological equipment and relatively other coefficients that may effect the sound energy propagation.

Abstract: Diffraction of in-plane wave and out-plane wave by a cylindrical nanohole is investigated. The surface elastic theory is used to consider the surface stress effects and to derive the boundary condition on the surface of the nanohole. The plane wave expansion method is applied to obtain the scattering waves. The scattering cross section and far-field scattering amplitude are numerically evaluated. The influences of surface stress are discussed based on the numerical results.

Abstract: The sound level adjacent to the sound sources is mainly characterized by the straight sound. The dispersion sound ratio is increasing with distance increasing and within the limited range round the sound source, the sound level is higher, in the area with dispersion bodies even higher than in an empty area. The laws of sound propagation in empty areas are derived on classical geometric base. The laws of sound propagation in large areas with dispersion objects are also derived from these laws complemented with the Kuttruff ́s equation of reverberation process in media with dispersion bodies. Simultaneously the sound energy is according to the purpose divided into the straight sound and the reverberation. The straight sound is the energetic ratio of sound, that is during the way to destination not dispersed and the propagation laws are equal to empty areas propagation laws are equal to empty areas propagation laws. The dispersed sound is the ratio of sound energy that reaches the destination after one or more reflections. The energy result is then the sum of densities of dispersion and straight sound.

Abstract: We present a model for charged dislocations effects on III-V compound semiconductor based FinFETs performance. The model is developed to obtain momentum relaxation time and, from it, key device performance parameters such as effective mobility, threshold voltage, and finally saturation drain current. We find out that charged threading edge dislocation density of a FinFET channel should be smaller than about 10⁷ cm^-2 to ignore the dislocation scattering impact on the device performance which is roughly one order more strict condition than previously known condition for wurtzite GaN.

Abstract: Aiming at the absorption effect of fog suspended in the atmosphere on light, the paper established the removing-fog compensation adaptive model which can improve the atmospheric visibility and restore the normal work of outdoor system. The experimental results show that the removing fog image processed by the method of removing-fog compensation optimization can accord with the requirement of human visual, and it can be used in real-time video monitoring as the fast computing speed. The method not only can be used in foggy video which the fog distributed uniformly, and can assess the visual quality for the images processed.

Abstract: A computational method is presented to evaluate non-compact noise produced by compressible flow interacting with arbitrarily shaped solid objects. In conjunction with compressible calculation, hybrid computational aeroacoustics method is used to develop noise calculation. Scattering effect induced by non-compact surfaces is the prime objective to study in the present research, the fluctuations of flow variables are decomposed into hydrodynamic component mainly produced by fluid flow and acoustic component mainly produced by noise propagation. Non-compact integral surface is divided into enough fine elements, and scattered pressure on body surface is firstly captured by acoustic calculation. The acoustic noise of two dimensional stationary circular cylinders at low Mach number is considered with diameter D=0.019m (Re=90000) and D=1m (Re=100). Numerical results indicate that the noise predicated by the present method is as accurate as noise directly computed by Curles equations at low frequency, the total noise of cylinder model has a dipole-like directivity, but a petal-like pattern at high frequency when scattering effects gradually strengthen. This method exactly captures scattered noise produced by noncompact bodies, and the influence of scattered noise with increased frequency is evaluated simultaneously in this paper.