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1.
Bipolar resistive switching (RS) phenomenon without required electroforming has been observed in epitaxial (111)-oriented BaTiO3 (BTO) thin films deposited by PLD technique on conducting Nb-doped substrate of SrTiO3 (NSTO). Negative differential resistance (NDR) is observed at about −5 V when the maximum of positive voltage exceeds 7 V and the compliance current is more than 1.5 mA. And bipolar resistive switching has also been observed. In addition, the resistance of LRS decreases with increasing compliance current or the maximum of positive voltage while that of HRS barely changes, and the resistance of HRS increases with increasing the absolute of maximum of negative voltage while that of LRS scarcely changes. A typical rectifying behavior is observed when the maximum of positive voltage is less than 4 V (such as 2 V). In this case, the reverse biased current is strongly enhanced under illumination of white-light, and vice versa. The resistance of LRS and HRS can be controlled by the applied voltage or the compliance current. The rectifying behavior can be controlled by the white-light. The transition from rectifying behavior to bipolar resistive switching can be controlled by the applied voltage. The above results were discussed by considering the oxygen vacancies that can trap or release electrons as a trapping layer at the Pt/BTO interface. 相似文献
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提出了一种用于动态研究的新方法-孔径径向扫描白光散斑干涉法,介绍了两孔和直三孔径向扫描器.该方法是一种非接触式的用于动态测量的白光散斑法.分析了孔径径向扫描白光散斑干涉法的基本原理,给出了白光散斑全场滤波分析的平均光强解析式和实验结果.该方法的优点是利用散斑的调频技术能在一张白光散斑图上记录物体的连续动态变形的信息,在全场滤波分时,能将物体动态变形的信息方便地提取出来,得到清晰的全场白光散斑条纹图.直三孔径向扫描法能得到物体在x方向、y方向和45°方向上的变形信息.在实时全场滤波分析观察时,将滤波孔连续地沿径向扫描,可观察到物体连续动态变形的全过程,从而为物体的动态研究提供了一种新方法. 相似文献
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WANGZhao-ying WUXing TIANHe-bin LIShi-chen 《半导体光子学与技术》2003,9(2):102-106
The security of civil engineering is an important task due to the economic,social and evironmental significance.Compared with conventional sensors.the optical fiber sensors have their unique characteristics.Beijing durable,stable and insensitive to external perturbations,they are particular interesting for the long-term monitoring of civil structures.Focus is on absolute measurement optical fiber sensors,which are emerging from the monitoring large structural,including SOFO system,F-P optical fiber sensors,and fiber Bragg grating sensors.The principle,characteristic and application of these three kinds of optical fiber sensors are described together with their future prospects. 相似文献
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Yb3+/Tm3+/Ho3+ tri-doped Gd2Mo3O9 phosphors were synthesized by the high-temperature solid-state method. Under 980 nm near-infrared excitation, the white-light emission can be observed, which is consists of the blue, green, and red UC emissions. The green and red emission at 547 nm and 660 nm originated from the transition of Ho3+ (5S2, 5F4 → 5I8 and 5F5 → 5I8) and the blue emission at 475 nm attributed to the transition of Tm3+ (5G4 → 5H6). In this experiment, we selected the optimum concentration ratio of the three rare earths for the bright white emission. The Commission internationale de L’Eclairage (CIE) coordinates for the samples were calculated, and chromaticity coordinates were very close to white light regions. We find that the calculated CIE color coordinates of the Yb3+/Tm3+/Ho3+ tri-doped Gd2Mo3O9 phosphors changed with the incident pump power from 400 mW/cm2 to 1000 mW/cm2. The upconversion luminescence mechanism of the samples was discussed on its spectral. The white light may be proved to be a candidate material for applications in various fields. 相似文献
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白光光学信息处理及其彩色摄影术 总被引:8,自引:3,他引:5
本文阐述了白光光学信息处理的物理基础,给出了近10年来使用所研制 的仪器和设备在实际应用中取得的结果,提出了一种新型数码相机的方案和彩色档案存储的新技术并为大学高等物理提供了一个现代光学和数字图像的实验素材。 相似文献
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白光干涉型Michelson光纤扫描干涉仪 总被引:1,自引:0,他引:1
介绍了一种白光干涉型Michelson位移传感器,Michelson干涉仪的一臂由光纤F-P腔构成,作为传感头,另一臂由电磁位移器带动的反射镜构成,提供相位补偿。理论分析和实验结果表明,在150μm的动态范围内,该传感器的位移测量重复性达到0.5μm,测量不确定度为.5μm。本文还提供了进一步提高测量精度和响应速度的方法。 相似文献
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Y2O2S:Dy3+, Mg2+, Ti4+ white-light long-lasting phosphors were synthesized by sol–gel method. Y2O2S:Dy3+, Mg2+, Ti4+ phosphors were characterized by X-ray diffraction, photoluminescence spectroscopy and thermally stimulated spectrometry. The results showed that the samples calcined at different temperatures from 900 °C to 1200 °C were composed of the pure Y2O2S phase. Under 359 nm UV excitation, the phosphor presented white luminescence due to mixing of the dominating emissions centered at 488 nm (blue) and 579 nm (yellow), corresponding to 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions of Dy3+, respectively. Both the fluorescence intensity and afterglow time reached the largest values in the phosphor calcined at 1200 °C and the afterglow time could last for over 65 min (≥1 mcd/m2) when the excited source was cut off. 相似文献
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我们研究了一种新的白光联合变换相关器,即在频谱面上利用液晶光阀对联合傅氏干涉谱进行变换,然后用白光做为液晶光阀的读出光,实现相关变换。利用部份相干光传播模式,导出这种白光联合相关器保留了对复振幅的线性运算能力,结果表明,这种相关器能得到较好的相关结果,并能有效地抑制相干噪声。 相似文献
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Orange-red light-emitting Sm3+-doped cerium oxide (CeO2) ceramic powder with various concentrations of Sm3+ ions was prepared through a sol-gel process. X-ray diffraction and Rietveld analysis confirmed the formation of a purely cubic structure with a space group of . The lattice parameters and unit cell volumes of the CeO2:Sm3+ powder increased with the concentration of Sm3+ ions. The energy-dispersive X-ray spectra and corresponding mapping images confirmed the elemental composition and adequate dispersion of all elements in the CeO2:Sm3+ powder. A broad excitation band at approximately 365?nm was observed in the excitation spectra of CeO2:Sm3+ phosphors owing to the charge transfer transition from O 2p to Ce 4f orbitals. The Sm3+ doped CeO2 phosphors emitted sharp luminescence with a main peak at 615?nm under excitation at 360?nm. The spectral analysis revealed that the CeO2:Sm3+ phosphors exhibited strong orange-red emission. Concentration quenching was observed in the CeO2:Sm3+ phosphors with 0.5?mol% of critical concentration of Sm3+ ions due to dipole dipole interaction of two nearest Sm3+ ions. The quantum efficiency was observed as high as 58%. The thermal stability of the present materials was estimated with the evaluation of activation energy as 0.31?eV. The broad excitation band and sharp orange–red emission indicated the potential use of CeO2:Sm3+ phosphors for white light-emitting diodes. 相似文献