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101.
Yage Zhan Hua Wu Qinyu Yang Jincheng Pei Xichun Yang 《Optics and Lasers in Engineering》2009,47(11):1317-1321
A multi-parameter and multi-function, but low-cost, optical fiber grating sensor with self-interrogation and self-discrimination capabilities is presented theoretically and experimentally. The sensor bases on three fiber Bragg gratings (FBG) and one fiber long period grating (LPG). Strain, vibration, pressure, ordinary temperature (−10 to 100 °C) and high temperature (100–800 °C) can be measured by the sensor. When high temperature (100–800 °C) is measured, the LPG is used as a high temperture sensor head and FBG1 is used as an interrogation element. Alternatively, when one of the other four measurands is measured, FBG1 (or FBG2) is used as a sensor head and LPG is used as an interrogation element. When two of the other four measurands are measured simultaneously, FBG1 and FBG2 are used as sensor heads and LPG is used as a shared interrogation element. FBG3 is used as a reference element to eliminate the errors resulted from light source fluctuation and the cross-sensitivity between measurand and environmental temperature. The measurands can be interrogated according to the signals of the photodiodes (PDs), which are related to the relative wavelength shift of the LPG and the FBGs. Experimental results agree well with theoretical analyses. The interrogation scheme is immune to light source fluctuation and the cross-sensitivity between measurands and enviromental temperature, and also the dynamic range is large. 相似文献
102.
Lifshits Mikhail A.; Linde Werner; Shi Zhan 《Proceedings London Mathematical Society》2006,92(1):224-250
We investigate RiemannLiouville processes RH, with H> 0, and fractional Brownian motions BH, for 0 < H <1, and study their small deviation properties in the spacesLq([0, 1], µ). Of special interest here are thin (fractal)measures µ, that is, those that are singular with respectto the Lebesgue measure. We describe the behavior of small deviationprobabilities by numerical quantities of µ, called mixedentropy numbers, characterizing size and regularity of the underlyingmeasure. For the particularly interesting case of self-similarmeasures, the asymptotic behavior of the mixed entropy is evaluatedexplicitly. We also provide two-sided estimates for this quantityin the case of random measures generated by subordinators. While the upper asymptotic bound for the small deviation probabilityis proved by purely probabilistic methods, the lower bound isverified by analytic tools concerning entropy and Kolmogorovnumbers of RiemannLiouville operators. 2000 MathematicsSubject Classification 60G15 (primary), 47B06, 47G10, 28A80(secondary). 相似文献
103.
This paper introduces Bohmian mechanics (BM) into the
intense laser-atom physics to study high-order harmonic generation.
In BM, the trajectories of atomic electron in an intense laser field can
be obtained with the Bohm--Newton equation. The power spectrum with the
trajectory of an atomic electron is calculated, which is found to be irregular.
Next, the power spectrum associated with an atom
ensemble from BM is considered, where the power spectrum becomes
regular and consistent with that from quantum mechanics. Finally,
the reason of the generation of the irregular spectrum is discussed. 相似文献
104.
105.
基于两个级联偏振调制器,提出了一种高频谱纯度、稳定的六倍频微波信号产生方法。该方法通过适当调整偏振片的偏振方向、射频驱动信号电压和相位,实现无光滤波器条件下、任何波段六倍频微波信号的产生。利用Optisystem平台搭建的仿真系统,以S波段4 GHz信号为例,验证了该设计系统产生的六倍频信号质量,并分析了非理想射频驱动电压和相位对六倍频信号质量的影响,结果表明:该设计系统能产生最大光边带抑制比、射频无杂散抑制比分别为21.3,15.2 dB的六倍频微波信号;且非理想驱动电压和相位差的偏离应控制在理想值5%的范围之内。 相似文献
106.
Quantum teleportation is important for quantum communication. We propose a protocol that uses a partially entangled Greenberger–Horne–Zeilinger (GHZ) state for single hop teleportation. Quantum teleportation will succeed if the sender makes a Bell state measurement, and the receiver performs the Hadamard gate operation, applies appropriate Pauli operators, introduces an auxiliary particle, and applies the corresponding unitary matrix to recover the transmitted state.We also present a protocol to realize multiple teleportation of partially entangled GHZ state without an auxiliary particle. We show that the success probability of the teleportation is always 0 when the number of teleportations is odd. In order to improve the success probability of a multihop, we introduce the method used in our single hop teleportation, thus proposing a multiple teleportation protocol using auxiliary particles and a unitary matrix. The final success probability is shown to be improved significantly for the method without auxiliary particles for both an odd or even number of teleportations. 相似文献
107.
Deng L Hagley EW Cao Q Wang X Luo X Wang R Payne MG Yang F Zhou X Chen X Zhan M 《Physical review letters》2010,105(22):220404
We report the first experimental observation of strong suppression of matter-wave superradiance using blue-detuned pump light and demonstrate a pump-laser detuning asymmetry in the collective atomic recoil motion. In contrast to all previous theoretical frameworks, which predict that the process should be symmetric with respect to the sign of the detuning of the pump laser from the one-photon resonance, we find that for condensates the symmetry is broken. With high condensate densities and red-detuned pump light the distinctive multiorder, matter-wave scattering pattern is clearly visible, whereas with blue-detuned pump light superradiance is strongly suppressed. However, in the limit of a dilute atomic gas symmetry is restored. 相似文献
108.
The interaction between polychromatic fields and atoms is an important subject in quantum optics.Frequency locking for small frequency interval multi-field is usually required in some experiments.In this letter,we experimentally demonstrate a holistic scheme for bichromatic laser frequency stabilization.Compared with traditional saturation absorption methods and complicated frequency shift schemes,offset locking for bichromatic fields is simply achieved using polarization spectroscopy and Doppler effect.Frequency locking with a wide-range asymmetry of the detuning is also shown.Our scheme makes laser spectroscopy experiments with polychromatic fields more convenient. 相似文献
109.
提出了活化法测量DD中子产额的实验方法,该方法可提高DD中子产额测量的精度。方法基于铟同位素115In与DD中子的非弹性散射反应,活化反应释放的射线被HPGe探测器记录,根据活化系统标定灵敏度推算出中子产额。分析了探测器记录的活化射线数与中子产额间的关系。介绍了一套活化测量的系统设计。通过蒙特卡罗方法模拟了活化样品出射的射线数与样品厚度的关系,模拟结果表明:样品厚度取为1 cm可兼顾活化效率和测量精度。在加速器上对铟活化样品进行了标定实验,实验结果表明:在聚变中子产额大于2109的实验中可使用铟活化诊断方法,中子产额测量的相对标准误差在10%以内。随着聚变中子产额的不断提高,铟活化测量中子产额的精度可进一步提高。 相似文献
110.
The Al-Cu-TM (TM = transition metal) alloy system has attracted great attention for both excellent glass-forming ability and its interesting physical properties. In this work, an investigation into the crystal, electrical and elastic properties of the AlCu2TM (TM = Ti, Zr, and Hf) compounds has been conducted by first-principles calculations based on density-functional theory. The fully relaxed structure parameters of the AlCu2TM compounds are in good agreement with previous experimental and other theoretical results. Besides, the cohesive energies of all the AlCu2TM compounds have been evaluated. The energy band and densities of state of these compounds are also obtained. According to the calculated single crystal elastic constants, all the compounds are mechanically stable. The polycrystalline bulk moduli, shear moduli, Young’s moduli and Poisson’s ratio have been deduced by using Voigt-Reuss-Hill (VRH) approximations. The calculated negative Cauchy pressure and ratio of bulk modulus to shear modulus indicated that the AlCu2TM compounds are ductile materials. The Debye temperatures of the AlCu2TM compounds decrease with increasing the TM (Ti, Zr, and Hf) atomic number. 相似文献