Advanced Materials Research Vols. 433-440

Abstract: This paper presents an explicit dynamic finite element method (FEM) in conjunction with the forming limit diagram (FLD) to analyze the forming limit for the various arc radii of punch in micro deep drawing of square cup. In the present study, the tensile test and friction test are performed to obtain the material parameters of the electro-deposited copper foil according to the ASTM standards. Importing these properties, the numerical analysis is conducted by the explicit dynamic FEM. The FLD in numerical simulation is used as the criterion of the forming limit in micro deep drawing of the square cup. The forming limit, deformed shape, punch load-stroke relationship, height of cup and thickness distribution of square cup, are discussed and compared with the experimental results. It shows that a good agreement is achieved from comparison between simulated and experimental results. When the arc radii of punch increase with R_p=0.2, 0.5 and 0.8mm, the limit drawing ratio increases from 1.90 to 2.03 and 2.10. The forming limit of square cup increases with an increase of the arc radii of punch. From this investigation, the results of this paper can be used as reference in the relative researches and applications of micro forming.

Abstract: In the deep-drawing process, the application of low-frequency vibration to the blank material has recently been focused on with the aim of improving the friction performance between the die and the blank material. A servo-controlled press machine is suitable for applying low-frequency vibration to the blank during the deep-drawing process, because the punch speed and blank holder force (BHF) are easily controlled as process parameters by using the servo motors. In this study, a BHF with low-frequency vibration was proposed as a technique for improving deep-drawability, which is mainly affected by the friction performance and the lubricant condition. We found that the friction performance between the blank surface and the blank holder was decreased in the case of a BHF with low-frequency vibration since the lubricating oil rapidly flowed into the clearance during the forming process. Furthermore, for a BHF with low-frequency vibration, the punch force and the deformation resistance were lower than those in a deep-drawing test without low-frequency vibration.

Abstract: In this paper, we study the multicast waveband grooming in multi-domain optical networks and propose three heuristic algorithms, Per-Domain Multicast Grooming (PDMG), Virtual Topology Multicast Grooming (VTMG) and Hierarchical Multi-domain Multicast Grooming (HMMG). Simulation results show that, comparing with PDMG and VTMG, HMMG has the best performance of ports savings and the lowest blocking probability.

Abstract: With the rapid development of computers, communication and multimedia electronic products, application of high quality images is becoming more and more popular. Improvement of image quality is a very important subject at present. Basic on compression technology of static images, this subject raises adaptive quantitative methods for different images, adopts secondary calculation method during quantization, and then gives simulation validation to images by Matlab software. According to the rate of high-frequency and low-frequency of images, adjust quantization table to make the best effort of image compression.

Abstract: Cu-38Zn thin film (wt %) was deposited on the unheated microscope glass at the nanometer scale by DC magnetron sputtering. Subsequently, the nanocrystalline films were dealloyed in H2SO4 aqueous solution etching of zinc component, resulting in the formation of nanoscale porous copper film with average porous diameter of approximately 94 nm. The films microstructure and element composition were characterized by X-ray diffraction and scanning electron microscopy. The experimental results show that Cu-38Zn films are quasi-amorphous structure, porous copper film with different porous sizes is prepared by selective dissolution of zinc atoms from a nanocrystalline dual-phase film under free corrosion conditions, the grain size of the Cu-Zn films has an important effect on the dealloying process and the microstructures of the nanoscale copper films.

Abstract: The micro-column packed with porous nano-barium- strontium titanate microspheres, joining with injector, a new manual-controlled injection porous nano-barium- strontium titanate microspheres enricher (PBSTME) was prepared. The enrichment capability of the PBSTME for the heavy metal ions, such as zinc, nickel, copper, manganese, cobalt and silver was investigated. The results showed that all the heavy metals studied could be quantitatively retained by the PBSTME in the pH range of 5–8, and then eluted completely with 2 mol•L^-1 HNO₃. The detection limits of this method for zinc, nickel, copper, manganese, cobalt and silver ions were 0.028 μg•L^-1, 0.2μg•L^-1, 0.031 μg•L^-1, 0.022 μg•L^-1, 0.057μg•L^-1 and 0.039 μg•L^-1 with an enrichment factor of 50, respectively. A new method has been developed for the determination of trace heavy metal ions based on pre-concentration with a PBSTME prior to their determination by flame atomic absorption spectrometry. The method has been applied to the simultaneous determination of trace amounts of zinc, nickel, copper, manganese, cobalt and silver ions in water sample with satisfactory results.

Abstract: A sensitive method has been developed for the speciation of Cr(III) and Cr(VI) in natural water using a porous nano-barium-strontium titanate by sorghum straw template method (SPBST) and flame atomic absorption spectrometry (FAAS). The procedure presented based on Cr(III) and Cr(VI) show different adsorption capacities on the SPBST at different pH values, that is, Cr (III) selectively retained at pH 13, but Cr(Ⅵ) can’t be adsorbed. Whereas Cr (VI) retained at pH 1, but Cr(Ⅲ) can’t be adsorbed. Hence, Cr(Ⅵ) and Cr(Ⅲ) can be separated through changing pH value of medium. Cr(Ⅵ) and Cr(Ⅲ) adsorbed on the SPBST can be completely eluted using 1•0 mol•L⁻¹ NaOH and 1.0 mol•L⁻¹ HCl, respectively. And Cr(Ⅵ) and Cr(Ⅲ) were determined by FAAS, The preconcentration factor of the method was 100. At the optimum conditions determined experimentally, the adsorption capacities were calculated to be 21.6 mg•g⁻¹ and 7.3 mg•g⁻¹, respectively. The proposed method was applied to the determination and speciation of chromium in tap water, lake water and wastewater samples with satisfactory results.

Abstract: A multiresidue immunoassay method for determination of Fluoroquinolones (FQs) residues has been developed. For this purpose, NHS ester technology was employed to synthesize the immunogen and coating antigen of Norfloxacin (NFLX). SDS-PAGE, UV-visible spectra and Infrared spectra identification showed that the artificial antigen was conjugated successfully. Based on the square matrix titration, an icELISA method was established. The dynamic range in assay buffer was from 0.038 to 112.8 ng/mL, with LOD and IC50 value of 0.02 ng/mL and 1.2 ng/mL, respectively. This assay showed a high cross-reactivity to Ciprofloxacin (86%), Enrofloxacin (75%), Difloxacin (63%), Sarafloxacin (57%) and Pefloxacin (33.8%). The chemical effects on assay performance showed that the physiological pH (7.4) in assay buffer pursued the maximum absorbance (A_max) and the most sensitive IC50 values. The results suggest the artificial antigen was synthesized successfully, and the established immunoassay could be used for simultaneous detecting of Norfloxacin, Ciprofloxacin, Enrofloxacin, Difloxacin, Sarafloxacin and Pefloxacin residues in animal-original food samples.

Abstract: It is very important that how to improve wind resistance of bridge when design suspension bridge. In this thesis, main wind disaster of suspension bridges is recommended, and summarizes the historical lessons. For the particularity of suspension bridge with composite beam, some suggestions on how to heighten flutter wind speed are suggested.

Abstract: Double suction centrifugal pumps are widely employed in large water supply projects. In the present study, a double suction centrifugal pump with the staggered arrangement impeller in a domestic water supply project has been mapping and modeling, and then the symmetrical arrangement impeller of a double suction centrifugal pump has been designed for comparison. The commercial code was used to investigate the pump efficiency and the time variation of pressure at the zone of volute tongue. This unsteady flow feature was investigated by the large eddy simulation (LES) method with the sliding mesh technology. The analysis indicated that the pump efficiency of the double suction centrifugal pump with staggered arrangement impeller is lower than that with the symmetrical one. The frequency of pressure pulsation at the volute tongue is consistent with the blade passing frequency. The staggered arrangement impeller can reduce the levels of pressure pulsation significantly.