Advanced Materials Research Vols. 403-408

Abstract: Linear-LM pulse-compression signal has been widely used in modern radar for its characteristics of far detection range and strong ability of anti-jamming. SNR of Linear-FM pulse-compression radar is needed to be measured real-time in the course of estimating its anti-jamming ability quantitatively. Aiming at the performance of this radar, SNR estimating arithmetic in frequency domain is put forward in this paper and the model is validated by simulating in Gaussian white noise background. Result shows that the high speed operation arithmetic is easy to implement and can be applied to estimating the anti-jamming effect of Linear-FM pulse-compression radar.

Abstract: The intelligent dispatch is important link in the intelligent electrical network construction, By the service architecture and the WEB technology, this article solves the municipal county intelligence scheduling problem. On the one hand, it has solved the dispatching and data-sharing issues of the inter-county, realized the inspection which moved to the county, the information uploaded which moved to the super rank; on the other hand, it has released the dispatching personnel from the traditional paper, the form and the man-dispatch to attain the more standardized dispatching system and raise the work quality and efficiency; and finally, to promote the management standard of the municipal county dispatch completely.

Abstract: In this paper, we consider the existence of positive solutions for the initial value problem of nonlinear fractional differential equations where and is the Riemann–Liouville fractional derivative. By using the Nonlinear Alternative of Leray and Schauder theorem, some sufficient conditions for the existence of at least one positive solution for the initial value problem are established.

Abstract: In this paper, a real-time fog detection method using a low cost b&w camera is presented. This method is based on gray histograms which would show the correspondence relationship between the gray value and the number of the pixels. Compared with foggy-free images, we notice some characteristics of foggy images, and these characteristics are also reflected in their gray histograms. Using the data from a gray histogram and a series of thresholds, we can detect whether the original image is under fog conditions. Moreover, we divide the weather conditions into three fog levels. Some experimental results and conclusions about this work are presented.

Abstract: In hybrid renewable power systems, the use of a multiple-input dc/dc converter (MIC) leads to simpler circuit and lower cost, compared to the conventional use of several single-input converters. This paper focuses on the optimizing design of MIC. Different from a single–input DC/DC converter, the parameters design of a MIC is very complicated. This is because the converter will operate in multiple operation modes, in which the power sources can deliver power o the load either simultaneously or individually. In this paper, an optimizing design method is proposed with the considerations of the multiple operation modes. A dual-input Buck converter is taken as an example to show the design method and a prototype is built to verify the theoretical analysis.

Abstract: The separation energy consumption of methane and nitrogen mixture of 3 kinds of typical method, Cryogenic (DC), Pressure Swing Absorption (PSA) and Membrane (MEM), was calculated by Aspen Plus in this paper. The result shows that at 35°C, the ratio of methane and nitrogen is 1, the separation energy consumption of 3 methods are 5.2, 3.6 and 2.6×104kJ/kmol, respectively. The ratio of calculated energy consumption to theoretical consumption is 2.3, 1.6 and 1.2, the energy consumption of DC is the highest, then PSA, MEM is lowest. This work is to give some reference for the selection of CH4/N2 separation.

Abstract: Iterative Learning Control (ILC) has recently emerged as a powerful control strategy that iteratively achieves a higher accuracy for systems with repetitive tasks. The basic idea of ILC is to construct a compensation signal based on the tracking error in each repetition so as to reduce the tracking error in the next repetition. In this paper, particle swarm optimization (PSO) is proposed to optimize the input of iterative learning controller. The experimental results confirm that the proposed method not only has higher tracking accuracy than that of Improved Genetic Algorithm (IGA) and traditional Genetic Algorithm based elisit strategy (EGA), but also has the advantages of simple algorithm and good flexibility. And compared with conventional iterative learning control methods, it is easy to solve the optimal input for non-linear plant models.

Abstract: Industrial Robots design is always a challenge in terms of the materials being chosen for manufacturing the mechanical elements of the robots. The present paper is a theoretical study on the effects of temperature to the positioning precision of the robots with mechanical elements having composite materials in their structure. A case study was made on a SCARA industrial robot structure.

Abstract: The ferroelectric and electrical properties of potassium nitrate (KNO3): polyvinylidene fluoride (PVDF) composite layers prepared by melt press method have been studied. The stability of ferroelectric phase (phase –III) of potassium nitrate (KNO3) in the composite layers at room temperature have been analyzed. The temperature dependence of ferroelectric hysteresis loop (P-E) characteristics have been investigated in the composite layers. The electrical conductivity (σ) and dielectric behaviour of composite layers have been characterized. The conductivity and dielectric variation with temperature during heating and cooling modes has been found to provide the knowledge of phase transition in the composite. The capacitance –-voltage (C-V) and conductance - voltage (G-V) characteristics clearly show the ferroelectric butterfly loop, which is attributed to the features of ferroelectricity in the composite layers at room temperature. The coexistence of ferroelectric phase (phase III) with paraelectric phase (phase II) has also been observed at room temperature in the composite layers during dielectric and conductivity measurements.

Abstract: Micro-Vibrations, generally defined as low amplitude vibrations at frequencies up to 1 kHz, are now of critical importance in a number of areas. One such area is onboard spacecraft carrying sensitive payloads where the micro-vibrations are caused by the operation of other equipment. In this paper a rectangular simply supported flexible panel is considered. The equipments are located on this panel as lumped masses and the micro-vibrations are induced by some concentrated forces. The piezoelectric layers are attached on both sides of the panel as sensors and actuators. The governing equations of motion are derived based on Lagrange-Rayleigh-Ritz method. An adaptive control scheme is applied to reduce the panel vibrations. Finally the simulation results show the advantages of the adaptive control algorithm.