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In traditional processing, a large number of G01 blocks are adopted to discretize free surface or curve for NC machining. But, the continuity of G01 line segments is only C0, which may lead to discontinuity of axis acceleration, resulting in the frequent fluctuation of tool motion at the junctions in high-speed machining, deteriorating the quality of work piece, and reducing processing efficiency. To solve this problem, a local smoothing interpolation method is proposed in this paper. At first, the analytic relationship between the continuity of the trajectory and the continuity of the axes motion is first systematically described by formula. Based on this relationship, a local smoothing algorithm and a feed-rate scheduling method are proposed to generate a C2 continuous tool path motion with axis-acceleration continuity. The local smoothing algorithm smoothes the corners of G01 blocks by the cubic B-spline according to the cornering error tolerance specified by the user. After the feed rate at critical points of smoothed tool path was determined by a modified bidirectional scanning algorithm by considering constrains of chord error and kinematic property, an iterative S-shape feed rate scheduling is employed to minimize residual distance caused by round of time while ensuring the continuity of feed rate and acceleration. Then, a look-ahead interpolation strategy combined with smoothing algorithm and feed-rate scheduling as mentioned is proposed for real-time interpolation of short line segments. At last, simulations are conducted to verify the effectiveness of the proposed methods. Compared with the traditional G01 interpolation, it can significantly improve the processing efficiency and shorten the processing time within error tolerance. [ABSTRACT FROM AUTHOR]

Energy dissipations induced by the hydraulic jump and the trajectory jet are the most widely known as the two dissipation modes at the downstream of flood discharging structures, which are often considered quite different even contradictory. However, such two energy dissipators can be used jointly and harmonically. In this paper, a new type of stilling basin with a shallow-water cushion and a triangular bottom deflector is proposed based on two different scale physical model tests of the flood discharging tunnel No.2 of Luding hydropower project. The experimental results show that the flow regime of the hydraulic jump in the presented stilling basin with bottom deflector enjoys a good and stable performance within a large range of flow rates and the energy dissipation rate is considerably high as compared to the conventional stilling basin even at a low Froude number. The results also indicate that the stilling basin with triangular bottom deflector has a better performance in improving the potential cavitation erosion according to the analysis of the pressure and the cavitation number compared to the trapezoidal one. The proposed new type of shallow-cushion stilling basin with a shallow-water cushion can be applied in similar energy dissipation projects with low Froude number and large range of flow rates. [ABSTRACT FROM AUTHOR]

A rapid and sensitive method was optimized and validated for the separation and quantification of derivatized monosaccharides in polysaccharide from Potentilla anserine L. using 1-naphthyl-3-methyl-5-pyrazolone (NMP) as precolumn derivatization reagent by capillary zone electrophoresis (CZE). On the basis of the optimum conditions, nine NMP-derivatized monosaccharides achieve baseline resolution within 16 min. The developed method has been successfully applied to analyze component monosaccharides of three Potentilla anserine L. samples, which were obtained by gradational precipitation with 50, 70, and 90% aqueous ethanol, respectively. The polysaccharide precipitated from 50% ethanol solvent was composed of fucose, mannose, xylose, glucuronic acid, glucose, rhamnose, galacturonic acid, galactose, arabinose in molar proportion of 1:1.65:1.99:5.08:7.38:8.14:13.05:27.41:39.02; the corresponding molar proportions for polysaccharide obtained from 70% ethanol solvent were 1:1.64:1.65:4.52:13.96:9.13:26.30:10.52:18.00; fucose and galacturonic acid were not found in the polysaccharide precipitated from 90% ethanol solvent, and mannose, xylose, glucuronic acid, glucose, rhamnose, galactose and arabinose were determined with molar proportion of 1:0.87:1.77:2.78:1.69:2.58:2.49. Quantitative recoveries of the component monosaccharides in the polysaccharide were in the range of 93.3–105.1% and the relative standard deviation (RSD) values fell within 3.4–6.3%, respectively. The results demonstrated that the proposed CZE method was precise and sensitive for the analysis of the composition of polysaccharide. [ABSTRACT FROM AUTHOR]

The effect of ultrasound irradiation on molybdenum trioxide has been investigated. Under ultrasonic irradiation, spherical-like MoO3 nanoparticles were obtained, while bulk-like MoO3 nanoparticles were prepared without ultrasonic irradiation. The changes in the physicochemical properties of MoO3 have been investigated using techniques such as X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and ultraviolet and visible spectroscopy (UV-vis). The physicochemical changes of MoO3 due to ultrasound irradiation have been attributed to the sonochemical cavity collapse onto the molybdenum trioxide particles. The ultrasonically prepared particles can also greatly improve the photochromism efficiency. [ABSTRACT FROM AUTHOR]

A hybrid model that combines both physical and numerical models was employed to simulate the velocity field in a river area in complex geometry with multiple plunging jets. The simulation was based on experiments concerning energy dissipation and scour prevention at the Xiluodu Hydropower Station on the Yangtze River. The calculated results indicate that the complex geometry of the river area has a significant influence on the velocity field, especially on the circulation flow pattern at upstream and downstream of the plunging area and on the asymmetric characteristics of the spiral flow near both banks. The scour characteristics of the downstream river bed caused by the multiple jets were also predicted and analyzed according to the characteristics of the calculated velocity field. The good agreement between the simulated and experimental results indicates that the hybrid model can be used to effectively solve complicated 3-D problems with complex geometric and inlet conditions. Such problems may not easily be solved by using either a physical or a numerical model alone, and therefore the method presented in this article is considered to be a practical and effective way of dealing with this kind of problems. [ABSTRACT FROM AUTHOR]

In this paper by means of generalized shooting method and homotopy technique a numerical method was given for computing free multipoint boundary value problem proposed in the intervention of exchange rate by Cadenillas and Fernando Zapatero. A numerical example was given for illustrating the validity of this method. [ABSTRACT FROM AUTHOR]

In this paper, a new class of triangular summation operators based on the equidistant nodes was constructed. It is proved that this class of operators converges uniformly to arbitrary continuous functions with the period 2π on the whole axis. Furthermore, the best approximation order and the highest convergence order are obtained. In contrast to certain operators constructed by Bernstein and Kis in the previous works, the convergence properties of the new operator constructed in this paper are superior. [ABSTRACT FROM AUTHOR]