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131.
本文通过正电子湮没寿命谱分析了ZrO_2材料电导率σ与稳定剂含量的关系,研究表明材料中的“有效空位量”是决定σ的关键因素,解释了σ随稳定剂含量的变化规律  相似文献   
132.
Dialectic operator fuzzy logic   总被引:1,自引:0,他引:1  
Dialectic operator fuzzy logic (DOFL) is presented which is relevant,paraconsistent and nonmonotonic.DOFL can vividly describe the belief revision in the cognitive process and can infer reasonably well while the knowledge is inconsistent,imprecise or incomplete.  相似文献   
133.
姜云飞 《计算机学报》1995,18(7):517-522
本文提出了L集合的概念以及一种新的使用L集合的一阶数据库询问求值方法。因为这种方法对原数据库只增加一个新字句,所以询问求值的效率大为提高,而且因为可以直接使用L集合回答对数据库的询问,求值过程比较简单。  相似文献   
134.
The performance of thermoelectric (TE) coolers is determined by the figure of merit of the TE materials ZT. In order to obtain the optimal performance of a superlattice microcooler, both the superlattice structure and the device were optimized in the design and the fabrication process. The thermal conductivities of InGaAs/InGaAsP superlattices with different periodic lengths were measured with the 3omega method. The result indicates that the superlattice at a certain periodic length has minimal thermal conductivity, which, in general, corresponds to an enhanced ZT. A 1D model was utilized to investigate the significant parameters in microcoolers. Based on the modeling results, a set of superlattice microcoolers were fabricated. The maximum cooling temperature that was reached is 0.76degC for the optimized cooler at room temperature.  相似文献   
135.
以氯化锂溶液为除湿剂,建立测试翅片式内冷型液体除湿器性能的试验台,分析溶液和空气进口参数对除湿器性能(除湿量和除湿效率)的影响.  相似文献   
136.
The structural, dielectric and piezoelectric properties of (1-x)(Bi1/2Na1/2) TiO3-xBaTiO3 ceramics were investigated for the compositional range, x=0.02, 0.04, 0.06, 0.08, 0.10. The samples were synthesized by a conventional solid-state reaction technique. All compositions show a single perovskite structure, and X-ray powder diffraction patterns can be indexed using a rhombohedral structure. Lattice constants and lattice distortion increase while the amount of BaTiO3 increases. The X-ray diffraction results show the morphotropic phase boundary (MPB) of (1-x)(Bi1/2Na12) TiO3-xBaTiO3 exists in near x=0.06-0.08. Temperature dependence of dielectric constant eT33/ε0 measurement reveals that all compositions experience one structural phase and two ferroelectric phases transition below 400℃: rhombohedral (or rhombohedral plus tetragonal) ferroelectric phase ←→ tetragonal antiferroelectric phase ←→ tetragonal paraelectric phase. Relaxor behaviors exist in the course of ferroelectric to antiferroelectric phase transition. Dielectric and piezoelectric properties are enhanced in the MPB range for ( 1-x)(Bi1/2Na1/2)TiO3-xBaTiO3.  相似文献   
137.
Optimum detectors for pilot symbol assisted modulation (PSAM) signals in Rayleigh and Rician fading channels are derived. Conventional PSAM as used on Rayleigh fading channels is also employed on Rician fading channels. It is shown that the conventional PSAM receiver is optimal for binary phase shift keying in Rayleigh fading but suboptimal for Rician fading and suboptimal for 16-ary quadrature amplitude modulation in Rayleigh fading. The optimum PSAM signal detector uses knowledge of the specular component and also jointly processes the pilot symbols and the data symbol. The performance of the optimum detector is analyzed and compared with that of the conventional detector. It is concluded that substantial gains can be achieved by exploiting knowledge of the specular component while joint processing of the data symbol with the pilot symbols may offer small benefits.  相似文献   
138.
目的有效利用结构健康监测系统中的多源传感器数据信息,进而提高复杂结构健康状况的正确诊断率.方法将BP神经网络与数据融合理论中的证据理论有机融合,提出一种决策级数据融合损伤识别新方法.为了验证所提方法的有效性,用1栋7自由度剪切型建筑模型的6种损伤进行了检验.结果研究发现,将BP网络和D-S证据理论相结合的综合诊断模型,可以有效地提高一些损伤模式的诊断率,具有良好的适应性.结论笔者所提方法优于单一信息建立模型的识别能力,表明它具有较好的容错性和识别精度,用于健康监测和损伤检测是可行的、有效的.  相似文献   
139.
Photoanodes, which are used in photoelectrochemical (PEC) water splitting, have been shown to be applicable in the construction of a PEC biosensing platform. This was realized by replacing water oxidization with oxidation of an appropriate test molecule. Here, we have demonstrated the feasibility of adopting photoanodes consisting of zinc oxide nanorods arrays decorated with plasmonic gold nanoparticles (Au NPs@ZnO NRs) for the self-powered PEC bioanalysis of glutathione (GSH) in phosphate-buffered saline (PBS) at an applied bias potential of 0 V vs. Ag/AgCl. This heterostructure exhibited enhanced PEC properties because of the introduction of the Au/ZnO interface. Under visible light illumination, hot electrons from surface-plasmon resonance (SPR) at the Au NP surface were injected into the adjacent ZnO and subsequently driven to the photocathode. Under ultraviolet (UV) light illumination, the photogenerated electrons in ZnO tended to transfer to the fluorine-doped tin oxide due to the step-wise energy band structure and the upward energy band bending at the ZnO/ electrolyte interface. These results indicate that plasmonic metal/semiconductor heterostructure photoanodes have great potential for self-powered PEC bioanalysis applications and extended field of other photovoltaic beacons.
  相似文献   
140.
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