Advanced Materials Research Vols. 383-390

Abstract: The speed-adjustable system of asynchronous motor has been widely used in industrial production. in motor control, magnetic control is a key problem, but in order to realize the control of motor, magnetic field must be tested. The testing methods about rotor flux according to the rotor field-oriented control of motor are discussed in this paper. The paper describes the present two rotor flux calculation models: Voltage model and Current model. It concretely analyzes mathematical expressions of these two models in different coordinates, and realizes the matlab simulation of two kinds of model, the simulation results are compared by observations of the magnetic chain calculation results.

Abstract: The air gap flux density distribution in different radius of three conditions such as stator iron without slotting, stator iron slotting under no load condition and stator iron slotting under load condition is discussed using the 2-D finite element method. The effect of slotting on the distribution of air gap flux density of permanent magnet brushless motor is also analyzed.

Abstract: The paper describes a small batching machine control system that takes chip C8051F040 as the core controller. The system that has automatic control and manual control modes can complete the high-precision automatic weighing of few powder and granular material. This article describes the composition of the control system and the major design of hardware, and provides more detailed software program scheme.

Abstract: The aim of this paper is to introduce a high-gain Boost circuit and to use the maximum power model to analyze the principles of maximum power point tracking (MPPT) in photovoltaic (PV) system .The principle is applied to the high-gain Boost circuit and control circuit, through a specific MPPT algorithm to change the duty cycle of Boost circuit realizes maximum power tracking and higher DC output voltage, the control circuit are formed by the CPLD and the AVR microcontroller, through which the control circuit to generate a varying duty cycle and 40KHz PWM pulse to control High-gain Boost circuit. Algorithm uses the incremental conductance method. Experiments show that maximum power point tracking effect is good.

Abstract: To build airport simulation system, several key techniques must be solved. Thus the Real-time and Practicality of the system can be enhanced, and a strong feeling of immersion can be given. This paper deeply gives research on the key techniques of sky simulation, rain and snow effect simulation, telescope simulation and multi-channel in the airport simulation system, and gives the implementation.

Abstract: A compound flocculant, Poly aluminous-ferric-sulphate (PAFS), was prepared with waste slag of a steel work, hematite tailings, concentrated sulfuric acid and fly ash .And it was one-step synthesized with different mole ratio of Fe (Ⅲ)/Al (Ⅲ). The description of product was sticky red liquid and yellow-green solid. Its concentration was 1.45～1.65g/ml, and the concentration of ferric ion is higher than 160g/L, aluminum ion between 10.29g/L and 99.18g/L, the basicity is higher than 12%. According to Ⅴ inferior quality water of DaLaTe plants from Yellow River (the third quarter of Baotou hedong district) we select products with Fe (Ⅲ)/Al (Ⅲ) mole ratio is 10:5. And product PAFS nearly 4 tons in the self-reaction kettle.

Abstract: PCC-AC composite pavement has the advantages of high carrying capability and excellent comfort. The maximum temperature gradient formula of PCC-AC composite pavement in Guangxi region is fitted. The loading stress, thermal stress and coupling stress in AC layer of with dowel bar can significantly reduced. All kinds of stresses are also decreased with the narrow dowel bar space. Therefore, the Shrinking joints of composite pavement with dowel bars can greatly reduce the probability of reflection crack initiation. As the thickness of AC layer, there is greater influence on thermal stress and coupling stress than on loading stress, The loading stress, thermal stress and coupling stress in PCC layer decreases with the thickness increasing of AC layer, their relationship is linear. The loading stress and coupling stress of PCC layer reduce significantly with increasing the PCC thickness. AC layer also plays a role in reducing the loading stress and coupling stress of PCC layer.

Abstract: Coal fires are emerging as a global threat with significant economic, social and ecological impacts, besides the loss of energy resources those fires cause air and water pollution and emit enormous amounts of green house gases (carbon dioxide and methane), how to prevent and extinct the fires has been a worldwide issue. According to the respective limitation and characteristic of gel fire prevention materials and foam fire prevention materials, a new thinking of foamed gel coal fire prevention materials is put forward creatively. Foamed gel that includes the characteristic of gel and foam possessed the property of accumulation. It also has the performance of sealing and secluding oxygen. This paper describes the composition and characteristic of foamed gel, as well as the laboratory production process. For large coal fire zones, the new fire prevention materials (Foamed Gel) have a broad application prospect.

Abstract: The joining process of SiCp/A356 composites is investigated. The two substrates are heated up to the melt temperature of Zn27Al filler metal by a resistance heating plate. At the time, a stirrer is introduced into the liquid weld seam in order to mix filler metal and two sides of substrates into a single uniform joint. After stirring, specimens are sectioned for the analysis of macro- and micro-structures along the weld region. The research shows that two typical joint interfaces with oxide film and without one were found. So, oxide film on the substrate wasn’t completely disrupted during stirring brazing at 500°C.And, the tensile strength of joint is only 50MPa.

Abstract: Block copolymer consists of two and more than two of different polymer links. Epoxy terminated polydtyrene (Ps-ep) active polymer was used to polymerize polystyrene (Pst)-polyethylene oxide (Peo) block copolymer P (st-b-eo). There were the mixtures of (Ps-ep), (Pst), (Peo) and P (st-b-eo) in the polymerization. It is necessary to separate (Ps-ep), (Pst), (Peo) and P (st-b-eo) in the mixtures in order to determine structure parameters of P (st-b-eo) block copolymers. We can know for certain their types of ABA, BAB and AB of polystyrene (A)-Polyethylene oxides (B) block copolymers with analysis of gel permeation chromatography (GPC).