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991.
Microstructure and corrosion behavior of electrodeposited nickel prepared from a sulphamate bath 总被引:1,自引:0,他引:1
Electrodeposited nickel was prepared from a sulphamate bath at different current densities ranging from 0.01 A cm− 2 to 0.1 A cm− 2. Based on the analysis of the microstructure, the corrosion behavior of the electrodeposited nickel in 3.5%NaCl solution was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). All the electrodeposits display active-passive-transpassive behavior in potentiodynamic polarization process. The electrodeposits with the best corrosion resistance are obtained at 0.05 A cm− 2. As for other electrodeposits, the corrosion potential and breakdown potential decrease with increasing current density used to prepare electrodeposits. However, the variation of both corrosion current density and passive current density is opposite to that of the corrosion potential. The changes in the charge-transfer resistance determined from the impedance spectra are consistent with the results determined from potentiodynamic measurements. 相似文献
992.
Jianhua Zhu 《Materials Letters》2007,61(13):2804-2809
The silicon carbide particles (SiCp) dispersion-strengthened copper matrix composites (Cu/SiCp) were fabricated by composite electroforming technology. The microstructure, tensile property and wear behavior of Cu/SiCp composites were investigated. The results showed that composites with different SiCp contents were obtained. The microstructure of the composite presented a uniform distribution of SiCp in the matrix and good interfacial integrity. The hardness, yield strength and rigidity of the composites increased with increasing SiCp content, but at the cost of ductility. Increasing SiCp content in the composite was not always beneficial to the ultimate tensile strength and wear resistance. The ultimate tensile strength increased with SiCp content increasing up to 16 vol.% and decreased as exceeding 16 vol.%, and the wear mass loss decreased with SiCp content increasing up to 21 vol.% and increased again as exceeding 21 vol.%. 相似文献
993.
A high optical quality Er3+-doped NaGd(WO4)2 single crystal with dimensions of ∅18 × 50 mm3 has been grown using the Czochralski method. The structure of the grown crystal was proved by X-ray powder diffraction. The accurate concentration of Er3+ ion in the crystal was measured. The absorption spectra, fluorescence spectra and fluorescence lifetime of the crystal were measured at room temperature. Green up-conversion luminescence has been observed when the crystal is excited at 965 nm. 相似文献
994.
Qi Liu Lifang Lai Xiujuan Fu Fangping Zhu Jianhua Sun Hongren Rong Mingyang He Qun Chen Zheng Xu 《Journal of Materials Science》2007,42(24):10113-10117
Hollow CoFe2O4 spheres consisted of CoFe2O4 nanoparticles were synthesized by a facile solvothermal treatment of an ethylene glycol solution of FeCl3 · 6H2O, CoCl2 · 6H2O, and NaAc at 200 °C in the presence of polyethylene glycol and oleic acid. The products were characterized by powder X-ray
diffraction, transmission electron microscopy, selected area electron diffraction, high-resolution transmission microscopy,
scanning electron microscopy. The magnetic properties were evaluated using a vibrating sample magnetometer. The probable mechanism
of the formation of Hollow CoFe2O4 spheres was discussed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
995.
Mobile RFID的安全和隐私问题研究 总被引:1,自引:1,他引:1
射频识别技术被广泛应用于物体的自动识别,广泛地部署射频识别的标签会给用户的隐私带来新的安全威胁。目前,射频识别出现一种融合的趋势,阅读器被集成到移动电话中。移动射频识别主要应用于普通终端用户,用户的安全和隐私是最优考虑的问题。论文描述了移动RFID的应用场景和安全及隐私威胁,重点描述了移动环境下特殊的安全和隐私危险及解决移动RFID安全和隐私问题的安全体系构架方案。 相似文献
996.
Liao Shaowei Yan Ping Xu Jianhua Wang Ya 《Microwave and Wireless Components Letters, IEEE》2007,17(4):292-294
In this letter, a novel realization of left-handed transmission line is presented; the proposed structure is based on identical symmetrical resonant-slot coupled cavity chain. The dispersion characteristic of the resonant-slot coupled cavity chain is analyzed by means of field theory and finite element method (FEM) eigenmode simulation, and a left-handed passband is proved to exist. A backward wave behavior is demonstrated unambiguously from FEM driven modal simulation. The phase front is observed to be in the opposite direction with respect to the energy one for a finite nine-unit cell prototype 相似文献
997.
998.
PDLLA/CHI/β-TCP/NGF composite films were prepared by a solvent evaporation method. The degradation characteristics of the poly(d,1-lactide)composite films were studied in vitro and in vivo. The acidity produced by poly(d,1-lactide)materials was not obvious.Adding chitosan andβ-TCP can relieve the acidity problem and improve strength performance of films.The NGF has influences on the degradation characteristics of films.It is verified that PDLLA/CHI/β-TCP/NGF composite films prepared by solvent evaporation method have excellent degradation characteristics.It can be used as a perfect biomaterial for repairing nerve injuries. 相似文献
999.
区域人力资本运营的差异比较研究 总被引:1,自引:0,他引:1
基于人力资源数量相当的前提下,对中部六省、东部五省人力资本运营的差异进行了比较研究,得到了区域人力资本运营差异的成因主要在于区域人力资本存量、人力人才资源使用效益、区域经济科技平台、人力人才资源素质差异等方面的结论,提出了中部地区人力人才资源开发一体化的战略思路. 相似文献
1000.
通过实验研究了纳豆芽孢杆菌的育种方法,对初始纳豆芽孢杆菌进行了紫外及微波诱变,采用牛奶-琼脂板筛选菌种,得到了目的菌株QBNW467.研究表明,采用牛奶-琼脂板法筛选诱变后的纳豆芽孢杆菌方法可行,用该法筛选出的菌株QBNW467的固体发酵产酶活性可达2200 IU.g-1. 相似文献