排序方式: 共有27条查询结果,搜索用时 15 毫秒
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为对电火花线切割加工机理有更深刻的认识,了解加工参数对加工精度的影响规律,介绍了一个电火花线切割加工粗加工的仿真系统。仿真系统通过对放电点的探索、工件的去除以及对线电极丝振动的分析,将实际的加工现象形象地再现于计算机上。为证实仿真系统的正确性,将仿真结果与试验结果进行了比较。在试验结果的获取中,为能够得到很难测量的线电极周围的放电间隙和工件形状数据,提出一种新的三维形状测量方法。通过对仿真结果和试验结果的比较,定性地证明了仿真方法的正确性。研究结果表明:改变线电极张力及伺服电压值时,从仿真过程得到的加工形状结果与试验得到的加工形状结果其倾向基本一致;加工缝端部的形状呈凸形还是呈凹形,取决于加工过程中放电爆发力和静电引力的相对大小。 相似文献
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SHIGEKI TOYAMA HIDETOSHI MORI MASANORI SUZUKI 《Particulate Science and Technology》2013,31(4):397-408
ABSTRACT The shear-stress distributions around cylinders in tube bundles were measured by means of the limiting current method and the flow inside the bundle was also visualized. In the case of the staggered bundle, the shear-stress distributions had two peaks by the effect of the jet streams generated at the front row spacing and the adjacent cylinder. While in the bundle with in-line arrangement, the front stagnant point was shifted about 30° downward and the traverse streams among the rows were observed. This traverse streams caused asymmetry of the shear-stress distributions with respect to the main flow axis. These results were discussed in connection with the fouling experiments investigated in dusty air. Particle deposition around cylinders could be qualitatively predicted from the shear-stress distributions, namely particles tend to deposit at positions where are less shear-stress in both tube arrangements. The size of particle deposited on the wake zone was coarser than that near the stagnant point behind the third row in both arrangements. 相似文献
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YOSHITAKA NAKAMURA KWI-YOUNG YUN SEIJI NAKASHIMA MASANORI OKUYAMA 《Integrated ferroelectrics》2013,141(1):226-233
ABSTRACT BiFeO3 thin films have been prepared on Pt/TiO2/SiO2/Si substrates by sol-gel method using precursor solutions of various elemental ratio (Bi:Fe = 1.1:1.0, 1.0:1.0, and 1.0:1.1). The θ < eqid2 > 2θ scan XRD patterns show all the films consist mainly of polycrystalline perovskite and the crystallinity of Bi:Fe = 1.1:1.0 is better than the others. SEM and AFM images show all BiFeO3 film have rosette structures, which consist of perovskite phase and matrix phase. The leakage current density measured at the temperature of 80 K is lower than 10?4 A/cm2 in all the films when the electric field reaches 1.6 MV/cm. The leakage mechanism of BiFeO3 thin film is dominated by Schottky conduction at 80 K. At 80 K, the remanent polarizations at maximum applied voltage of 2.8 MV/cm are 100, 49, and 44 μC/cm2 for the ratio of Bi:Fe = 1.1:1.0, 1.0:1.0, and 1.0:1.1, respectively. The saturated magnetization of BiFeO3 thin films at 80 K were found to be 14, 22.5, 15 emu/cm3 for the ratio of Bi:Fe = 1.1:1.0, 1.0:1.0, and 1.0:1.1, respectively. Among these ratio, BiFeO3 thin film deposited from precursor of Bi:Fe = 1. 1:1.0 gives the best ferroelectric property. 相似文献
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MINORU NODA TETSUO NOMURA DANIEL POPOVICI SHUUICHI MURAKAMI MASANORI OKUYAMA 《Integrated ferroelectrics》2013,141(1):35-40
Ba(Ti1—xSnx)O3 (BTS) ferroelectric thin films have been prepared by metal-organic decomposition method whose final annealing temperature was optimized to 700°C for dielectric bolometer. High temperature coefficient of dielectric constant (TCD) of 1–3%/K and low dielectric loss of 0.04 have been obtained in x = 0.15 and 0.17. Field-induced pyroelectricity of the BTS film was calculated to be an excellent value as high as 750 nC/cm2K. A series of dependence of DB output level were examined on important operation factors. The DB output level was increased when the period of supply voltage waveform is longer than both the electrical and thermal time constant of the DB detector. Finally, a stable infrared detection at temperature lower than 30°C was confirmed. 相似文献
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Abstract Solvent extraction of cobalt(Il) and nickel(II) in aqueous 1 mol dm?3 NaCl solutions with benzoyltrifluoro-acetone(Hbfa) in carbon tetrachloride has been measured in the absence and presence of tetrabutylammonium(tba+). In the absence of tba+, M(bfa)2 species is extracted and the extraction of cobalt(II) is better in the higher Hbfa concentration range but in the presence, M(bfa)3 ?tba+ type ion-pair is extracted and the extraction of nickel-(II) is always better. This is explained in terms that although the bis-nickel(II) complex is more stable, it is much more strongly hydrated than the bis-cobalt(II) complex and consequently its extraction is hindered but in the tris-complexes such a large difference of the hydration may not occur and the more stable nickel(II) complex is extracted better. 相似文献
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