Mechanical and Electrical Technology IV

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Authors: Z.M. Zhang, F. Li, H. Zhang
Abstract: In order to improve the punching process, further enhance the blanking section quality. This paper studied the common blanking of 60Mn and the fine blanking with negative clearance of 60Mn blanking work piece metallographic structure by using scanning electron microscope. The results show that the fine blanking with negative clearance process can increase the work-hardening degree and further thin the punching surface tissue, inhibit the crack, and make the blanking surface smooth. The tensile and tear result in the generation of cracks and burrs, and the extrusion forming of fine blanking with negative clearance inhibit the generation of cracks, and eliminate the conditions of the burrs. As the extrusion process, the degree of work hardening in fine blanking with negative clearance is higher than the common blanking, the organizations are more closed.
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Authors: Yu Wang, Yu Feng Chen, Yan Lu, Hui Fang Zhang, Zhi Guo Sun
Abstract: On the basis of analyzing the oil well cement corrosion mechanism by SO42- and HCO3-, the corrosion products, microstructure and compressive strength of cement stone were measured and the changing regularity and influence factors of compressive strength were analyzed under different experimental conditions. The following conclusions can be drawn. Under the interactive corrosion effect of SO42- and HCO3-, Ca(OH)2 in cement stone was dissolved out and consumed, the calcium silicate hydrate was decomposed, ettringite, gypsum, calcite and thaumasite were produced which destroyed the structure and components of cement stone primary products and led the compressive strength of corrosion cement stone decline. With the increases of ion concentration of corrosive solution, temperature and corrosive time, the compressive strength was decreased gradually, even collapsed completely.
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Authors: Yun Fei Shi, Xiang Jun Liu, Hui Jiao Nie, Yin Shu Liu
Abstract: The adsorption isotherm model of water vapor on activated alumina is an essential equation in designing the performance of adsorption. In this paper, the currently existed 14 isotherm models of water adsorption are summarized. The correlations among these models are analyzed. These isotherm models are evaluated by fitting the water adsorption data on Rhone-Poulenc activated alumina. The results show that AD-Toth, AD-LRC, AD-UNILAN and DMAP can fit the experimental data well.
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Authors: H. Du, F. Li, H. Zhang
Abstract: The stainless steels are used more and more in blanking process. To further enhance the quality of blanking fracture surface, this paper made the related experiments of fine-blanking with negative clearance in stainless steel. Through the comparison analysis between the fine-blanking microstructure and common blanking one with stainless steel, the result points out that the fine-blanking with negative clearance inhibit the warping in common blanking, make the work-hardening of material fracture surface improves, and which can have a more positive effect for the fine-blanking with negative clearance. Meanwhile, the work-hardening capacity of two blanking methods was different, and it can enhance the punching section entire strength commendably by fine blanking with negative clearance.
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Authors: Yang Li, Ping Ping Sun, Ai Qing Wu
Abstract: The femtosecond laser-induced forward transfer of the aluminum film had been studied experimentally by single-shot laser pulse (pulse duration 148fs, central wavelength 775nm). With the help of the atomic force microscope and scanning electron microscope, the dependence of morphology and dimension of deposited dots on irradiated laser pulse energy were investigated. It was revealed the threshold fluence for transfer was ~6.3 J/cm2 for the aluminum thin film with a thickness of ~500 nm. It also was presented the micro patterns of the aluminum film on a quartz substrate fabricated using the femtosecond laser-induced forward transfer .
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Authors: J.H. Li, Q.H. Xiao, H. Zhang, F. Li
Abstract: The fine blanking with negative clearance is a process with characteristic of the high blanking precision and the better fracture quality, so the blanking fracture surface structure are intensity. This paper has carried on the contrast and analysis between common blanking and the fine-blanking with negative clearance fracture face and burrs zone cavity metallographic and further indicated the different process blanking work-piece fracture face characteristics, illuminated the anti-corrosion of blanking fracture surface between different blanking process by using corrupt principium. The anti-corrosion of blanking fracture face could enhance wear resistance of blanking work piece evidently. Therefore, it could improve fatigue strength and the working life of work piece greatly.
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Authors: Ze Yi Sun, Yong Jiang Di, Zhi Qiang Zhong
Abstract: The microwave permeability of glass-coated magnetic alloy microwires / dielectric composite was investigated by apparent permeability linked with intrinsic permeability calculated based on Landau-Lifshitz function. The effect of diameter, length and microwires content on the composite effective permeability was simulated. The simulated results show that the complex permeability decreases with the increase of the microwires diameter and the wire content in the composite. The microwave magnetic resonance frequency increase distinctly with the lengthening of the glass-coated microwires. The full width at half maximum of the ferromagnetic resonance peak increases with the lengthening of the microwires and the decrease of the wire content.
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Authors: Bing Zhi Guo, Yun Zhao, Hong Bo Liu, Yang Jun Huang, Tong Ying Feng, Qing Ze Jiao
Abstract: To enhance the interfacial interaction in silica nanoparticles filled polymer composites , nano-SiO2 gel was prepared by a sol-gel route, and then it was modified in situ through a reaction of silane coupling agent with hydroxyl on the surface of SiO2. The modified nano-SiO2 gel was added to the system of light-cured varnish to prepare UV light-cured nanocomposite varnish. The structures and properties of varnish were studied using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and film performance test. The results showed that the modified nano-SiO2 was well dispersed in the varnish. After introduction of modified nano-SiO2, the fracture morphology of varnish film showed a corrugated shape, indicating the ductile fracture. The wear resistance of the varnish film increased by 50%, the coefficient of static friction reduced about 15%, and gloss improved to some extent.
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Authors: Yan Gao, Tao Luan, Tao Lv, Hong Ming Xu
Abstract: The V(1)-W(4.5)-Mo(x)/TiO2 catalysts was prepared by the incipient dry impregnation method. The catalyst samples were ground and sieved for 0.3~0.6 mm. The NO catalytic efficiency, selectivity against N2O of the catalysts were investigated on a fixed bed reactor under simulated exhaust gas with a typical gas composition. The addition of Mo enhanced the catalytic efficiency of V(1)-W(4.5)-Mo(x)/TiO2 catalysts at low temperature region, while lessened that at high temperature, especially at the temperature above 400 °C. Increasing the loading of Mo from 1.5% w/w to 4.5% w/w advanced the maximum catalytic efficiency from 78% to 99% and enlarged the temperature window of the catalyst. The acceptable NO conversion (>60%) was attained at temperature as low as 240 °C for V(1)-W(4.5)-Mo(7.5)/TiO2 catalyst. The presence of Mo promoted the N2O generation. The V(1)-W(4.5)-Mo(0)/TiO2 catalyst showed higher catalytic selectivity for NO compared to the catalysts loading Mo.
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Authors: Bo Wu, Yu Feng, Hong Kuan Yuan, Hong Chen
Abstract: Using the ab-initio calculations within the density functional theory (DFT), we have investigated the electronic structure, magnetism and half-metallic stability of Si-doped Heusler compound Ti2CoGa with Hg2CuTi-type structure. The results revel that the lattice constants and total magnetic moments in per unit obey the Vegard’s rule and the Slater-Pauling rule well, respectively. The most stable half-metallicity occurs at doping concentration x=0.75 because the Fermi level is located at the middle of the spin-minority gap. Our studies also indicate that the competition between RKKY-type indirect exchange and direct hybridization of d-electronic atoms plays a dominating role in determining the magnetism.
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