Abstract: Extending the investigations on (Na0.5K0.5)NbO3-based solid solution for lead-free piezoelectric ceramics, this paper consider the complex solid-solution system (Na0.5K0.5)NbO3–Bi0.5(Na0.85K0.15)0.5TiO3 [NKN-BNKT]. (Na0.5K0.5)NbO3 with 2 ~ 6 mol% Bi0.5(Na0.85K0.15)0.5TiO3 has been prepared following the conventional mixed oxide process. A morphotropic phase boundary (MPB) between orthorhombic (O) and hexagonal (H) was found at the composition 0.96NKN-0.04BNKT with correspondingly enhanced dielectric and piezoelectric properties. The electromechanical coupling factor and dielectric constant are higher for compositions near the MPB. The dielectric constant (KT33), planar coupling coefficient (kp) and thickness coupling coefficient (kt)of 0.96NKN-0.04BNKT ceramics were 1273, 34% and 38%, respectively.
Abstract: In order to realize anti-alteration function for License Plate Recognition System (LPRS), a uniform-field imaging system is designed and a corresponding anti-alteration algorithm is proposed. First, reflection characteristics of license plate and typical alteration material are measured. As a result, the two characteristics in near-infrared range fluctuate moderately and the former is notably lower than the latter. Then the uniform-field imaging system for visible-light and near-infrared is designed to capture the difference above effectively. Finally, the anti-alteration algorithm, composed of license plate location, character matching segmentation and alteration recognition, is introduced. Experimental results have indicated that visible-light and near-infrared images can be acquired stably by the proposed system under the condition of natural illumination and there are discriminable gray differences between license plate and alteration material in near-infrared images; and that success rate and average executive time of the algorithm are 86.5% and 157ms respectively.
Abstract: Solar photovoltaic technology is one of main approach to the scale utilization of renewable energy, but it is still limited by its high cost of power generation and material shortage. Dish concentrating photovoltaic technology is promising for lowering the cost of power generation with its advantages of higher concentration and higher photovoltaic conversion efficiency and lower consumption of solar cells. A detailed description of dish concentrating photovoltaic system was given, which include concentrator and photovoltaic device. The application of dish concentrating photovoltaic system was particularized. Finally, a detailed discussion of its future potential.
Abstract: High efficient cutting process technique is one of the main development directions of cutting process technology in the future, a reasonable choice of NC machining cutting parameter is an important way to realize high efficiency NC machining. NC machining cutting parameter optimization techniques were studied, using BP neural network, milling parameters optimization model of aluminum alloy shell structure was built, and the structure of BP neural network was analysed, realizing the optimizing of the BP neural network model, the improving of the convergence accuracy, convergence speed, prediction accuracy, generalization ability of BP neural network model, which optimized the cutting parameters selection and predicted the processing efficiency to provide a theoretical basis for the selection of high efficiency NC machining cutting parameter. Production practice showed: the application of the optimized cutting parameters of BP neural network for processing could improve processing efficiency, reduce costs notablely while guaranteeing the processing quality, and achieve the optimization of integrated application efficiency for high efficiency NC machining and NC machine, so it has a higher promotional value.
Abstract: Based on the pretreatment including acidification, purification and sodium ion exchange, the crude sepiolite was modified by microwave radiation-wet process and CTAB as modifier. The orthogonal experiment was used to optimize the modification process. Then the crude sepiolite and modified sepiolite were characterized by SEM, FTIR, XRD, TG-DSC and BET. The results showed that the optimum modification process parameters included CTAB dosage (1.0 cation exchange capacity (CEC)), microwave radiation time (4 minutes), ethanol concentration (50%/V:V) and radiation power (800W). Compared with crude sepiolite, oil removal rate from steel rolling wastewater increased from 41.34% to 96.78% with modified sepiolite prepared at the best process. Characteristic peaks of organic functional groups, enlarged interlayer distance (0.007nm larger than crude sepiolite), enhanced hydrophobicity, amplified specific surface area (104.4m2/g) and mesopore volume had been received from above characterization methods after modification. All of the above had proved that CTAB was successfully grafted onto sepiolite.
Abstract: The Canonical TSVD method is a kind of robust regularization method. In this paper, we first applied the Canonical TSVD method to finding L-generalized solution. We discussed a discrete method and how to compute the approximate solution of the Canonical TSVD method, then we gave some numerical examples. Finally, we drew some conclusions.
Abstract: Thermally sprayed carbide-based cermet coatings are being widely used for a variety of wear resistance applications. These coatings deposited by high velocity oxy-fuel (HVOF) technique are known to provide improved wear performance. In the present study, WC-12Co and Cr3C2-25NiCr carbide-based cermet coatings are deposited by HVOF. The microstructure and abrasion wear resistance of these coatings are compared. The correlation between coating microstructure and the coating wear behavior was investigated. The results indicated that WC-12Co coating has higher microhardness and better abrasive wear resistance in comparison to Cr3C2-25NiCr coating. The two HVOF sprayed carbide-based coatings have different abrasive wear behaviour.
Abstract: The seismic performance of K-shape eccentrically frames were researched by cyclic loading test method, in order to understand earthquake performance, stiffness degradation and dissipation mechanism of energy. It can be concluded that K-shape eccentrically frames provide high elastic stiffness and demonstrate excellent energy dissipation capacity in the plastic stage, the different length of the link beam of different layers has great influence on the energy dissipation capacity of the structure, when shear yielding of link beam occurs, stiffness degradation become apparent, the hysteretic curves were plump in shapes. Therefore, K-shape eccentrically frames have better hysteretic behavior and energy dissipation capacity, the results can provide a reference for the engineering design and related research.
Abstract: Considering the structure of some diesel engine cylinder head, its 3-D solid model and the finite element model is built, and after the load and constraint of is deal with, the stress and deformation the cylinder head with thermal-mechanical coupling is calculated with FEA ( Finite Element Analysis) software ABQUS. Analysis results find that: (1) the first main stress maximum value of cylinder head is up to 199.6MPa, which is less than 250MPa of the HT250 material ultimate tensile strength; (2) the deformation area is mainly in the flame face surface and fuel injector coxcombing, and the deformation of flame face is general symmetrical broadways and slightly large near the exhaust passage longways, while the deformation of fuel injector coxcombing is general symmetrical broadways and longways; (3) the structure design and strength of the cylinder head satisfy the design requirements.
Abstract: The primary purpose of this study is to develop a genetic algorithm based computer-aided roll pass optimal design (CAROD) system to support the generalized roll pass design for rod rolling, where the final products are round bars with different sizes. The system was developed to minimize the number of roll passes, decrease the trails and errors in industry, as well as extend the work range of multi-pass rolling systems for rod rolling. Parametric equations were established for geometrical modeling and graphic plotting, which can realize to the parametric transformation for roll pass design and optimization. A methodology based on a hybrid model was proposed to choose passes with different profiles for the multi-pass rod rolling system. In addition, an improved genetic algorithm (IGA) was employed for the optimization of roll passes. A MATLAB program was designed to achieve all these objectives. To reduce the complexity and computational burden of the software, some reliable empirical formulas were applied in this system. Finally, the proposed approach has been applied in a rod rolling system; through simulation and comparison of results against analytical solutions, numerical analysis and experimental data presented by other researchers, it was found that this system is reliable, effective and easier to use.