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101.
102.
Zhongqiu Hua Liang DongHaiqing Wang Shujie PengYu Wang 《Physica B: Condensed Matter》2011,406(14):2807-2810
In this paper, varistor property and mechanism of undoped tungsten trioxide (WO3) ceramic have been studied. Experimental results revealed that pure WO3 ceramic could exhibit a nonohmic behavior which was formed in the cooling process of ceramic, and very sensitive to heat treatment in different atmospheres. By comparison with the reported SnO2 and ZnO varistor systems, it is supposed that the surface of WO3 grain is more ready to adsorb oxygen and form high enough barriers at grain boundaries responsible for varistor behavior. The influences of heat treatments on the varistor properties of WO3 ceramic have been investigated. 相似文献
103.
W. Liu J.S. Wang X.L. Liao S.J. Zheng G.T. Ma J. Zheng S.Y. Wang 《Physica C: Superconductivity and its Applications》2011,471(5-6):156-162
To a high-Tc superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high-Tc superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets. 相似文献
104.
YBa2Fe3O8(YBFO)是具有三方钙钛矿结构的反铁磁(AFM)体,研究它的结构和磁性质对于我们认识三方钙钛矿结构具有重要作用.目前,关于固相法制备YBFO中退火温度方面的研究并不多,而控制退火温度是这种工艺中的重要环节.为制备高含量的YBa2Fe3O8,本文分别在760℃、950℃和1100℃退火温度下,采用固相... 相似文献
105.
106.
研究了两种典型的量子纠缠消相干现象对确定型量子态远程制备方案的影响.首先对该确定型远程制备方案进行了分析,得到该方案确定性和比特消耗情况; 然后通过分析制备过程中纠缠消相干现象对系统的影响得出: 在极化消相干过程中,该系统保真度与目标量子比特在Bloch球上的经度选择无关,仅与目标比特的纬度和消相干的大小有关;在相位消相干中,该系统的保真度不会受到消相干的影响,仅与目标量子态的纬度相关.
关键词:
远程制备
纠缠消相干
通信消耗
保真度 相似文献
107.
The crystal structure, magnetism properties, and density of states for FeAs layered compound SrFe2As2 have been investigated by using the density functional theory (DFT) method. The magnetism under a checkerboard nearest neighbor anti-ferromagnetic (NN AFM) and ferromagnetic (FM) order ground-state have been analyzed with substitution for Sr with K ion in Sr1−xKxFe2As2. The results indicate that the distortion of FeAs tetrahedrons is sensitive to the electron doping concentration. The system magnetism was suppressed by K doping in NN-AFM ground state instead of FM. The density of states at Fermi level N(EF) under NN AFM ground state would be regarded as a driving force for the increased Tc of Sr1−xKxFe2As2 system as observed experimentally. Our calculation reflects that NN AFM type spin fluctuation may still exist in the Sr1−xKxFe2As2 system and it may be an origin of strong spin fluctuation in this system besides the spin density wave (SDW) states. 相似文献
108.
CuO/tetrapod-like ZnO whisker (T-ZnOw) nanocomposites were successfully synthesized using a simple photo-deposition method. Some nanocomposites exhibit remarkably improved photocatalytic property, while the extents of the improvements vary with different Cu/Zn molar ratios and polyethylene glycol (PEG) concentrations. Moreover, it is found that excessively high Cu/Zn molar ratio or PEG concentration would reduce the photocatalytic property of the nanocomposites. A direct relationship between the morphology and the photocatalytic property of CuO/T-ZnOw was established and then analyzed by discussing the photocatalytic mechanism of the CuO/T-ZnOw nanocomposites. 相似文献
109.
应力系数的标定作为超声应力检测最为关键的环节,直接决定应力检测结果的准确性。传统的应力系数试验标定对于被测物的表面粗糙度、耦合剂厚度、声匹配块与被测物接触力等因素十分敏感,但缺少基本参照值。基于COMSOL建立多物理场耦合的超声应力检测模型,施加不同的拉伸载荷,计算临界折射纵波到达时间与不同应力值之间的关系,模拟标定45#钢的超声应力系数为13.7MPa/ns。单轴水平拉伸试验标定的45#钢应力系数为16.5MPa/ns。结果表明,通过两种方法标定的应力系数较为接近,试验标定的应力系数偏大,这是由于有限元方法能够消除试验过程中各种不确定因素对声时精确测量所造成的影响,能够更加纯粹的反映材料的声弹性效应,因此具有作为基础数据的参考价值。有限元方法作为传统试验方法的补充,可以减小试验标定数据的离散性,提高超声应力检测结果的可信度。 相似文献
110.
《Communications in Nonlinear Science & Numerical Simulation》2014,19(8):2866-2873
It was demonstrated recently that noise in an optimal window allows a bistable system to operate reliably as reconfigurable logic gates (Murali et al., 2009) [1], as well as a memory device (Kohar and Sinha, 2012) [11]. Namely, in a range of moderate noise, the system can operate flexibly, both as a NAND/AND/OR/NOR gate and a Set Reset latch. Here we demonstrate how the width of the optimal noise window can be increased by utilizing the constructive interplay of noise and periodic forcing, namely noise in conjunction with a periodic drive yields consistent logic outputs for all noise strengths below a certain threshold. Thus we establish that in scenarios where noise level is below the minimum threshold required for logical stochastic resonance (or stochastic resonance in general), we can add a periodic forcing to obtain the desired effects. Lastly, we also show how periodic forcing reduces the switching time, leading to faster operation of devices and lower latency effects. 相似文献