Phosphors BaY2 Si3 O10 : Bi3+, Eu3+ were synthesized by solid-state reaction method. Their phases and optical properties were analysed by using X-ray powder diffractionmeter and fluorescence spectrometer, respectively. The photoluminescence excitation (PLE) spectra of BaY2 Si3 O10 : Eu3+ consist of an enhanced broad charge transfer band (CTB) ranged 200~350 nm and a series of f-f narrow absorption band of Eu3+, the 5D0 →7FJ (J = 1 centered at 592 nm orange, J=2 at 615 nm red) transitions of Eu3+ present the typical orange-red emission band. When phosphors were excited by 285 nm light, the spectral overlap of emission band of Bi3+ and excitation spectra of Eu3+ demonstrated the energy transfer from Bi3+ to Eu3+ that positively enhance the orange-red luminescence of Eu3+ in BaY2 Si3 O10 : Eu3+ . The optimized doping is 0.4 mol% for Eu3+ . The critical transfer distance was calculated to be 1.604 nm, and the concentration quenching mechanism was mainly due to the electric quadrapole-quadrapole interactions.
The processes of vibration-rotation energy transfer between highly vibrationally excited KH (V=14~21) and CO2 were studied by using the pump-probe technique. KH is formed by the K (5P)+H2 reaction. The pulse laser prepares KH in the highly vibrational levels. Energy gain into CO2 resulting from collisions with excited KH was probed by using laser overtone spectroscopy technique. The rotational temperatures of CO2 (0000, J=32~48) states were obtained. The average rotational energy of the scattered CO2 molecules is increased by a factor of 2.33 when KH level V=14 increases to V=21. The nascent distributions of recoil velocities for collisions were determined from stimulated absorption line profiles of individual CO2 rotational states. The average translational energy of the scattered CO2 molecules is increased roughly linearly as a function of CO2 J state. Under single collision conditions, state-specific energy transfer rate coefficients for collisions of highly excited KH with CO2 were obtained. For V=19, the integrated rate coefficients kint increases by a factor of 4.5 to V=14, but when V>19, it decreases roughly.
Polarization ghost imaging system combines the strength and polarization detection, and expands the obtained information from the ghost imaging system. It can carry out effective target detection and identification. The conventional correlation polarization ghost imaging system requires a large amount of sampling data, and signal-to-noise ratio of the restored result is low. Polarization ghost imaging system based on compressed sensing was proposed to obtain the intensity and polarization information of the object using the detected information from the point detector. In the simulation experiment, the same reflectivity but different polarization characteristics of objects were employed. The results show that the high quality of the object intensity and polarization information can be obtained with fewer sample number compared with the correlation method, and it can improve the real-time performance. Finally, using image fusion algorithm to merge the intensity and polarization information, recognition by fusing information can be effectively carried out for a variety of objects.
The generalized variable-coefficient Burgers-Kadomtsev-Petviashvili (BKP) equation was investigated employing the Painleve analysis technique. It showed that the equation does not possess the Painleve property. Via the truncated Painleve expansion method and under the condition f(t)=cg(t) (c is a constant), an auto-Bcklund transformation for the generalized variable-coefficient Burgers-Kadomtsev-Petviashvili equation was derived. Based on the obtained auto-Bcklund transformation, some novel exact analytic solutions were given, including multiple soliton and periodic solutions.
By applying a direct symmetry method, the symmetry reduction, group invariant solution and many new exact solutions of the modified KdV-Zakharov-Kuznetsev equation (mKdV-ZK for short) were obtained, which include Jacobi elliptic function solutions, hyperbolic function solutions, trigonometric function solutions, and so on. The conservation laws were derived at last.
In order to measure ultrashort pulse more accurate, wavelet transform was applied to spectral phase interferometry of direct electric reconstruction (SPIDER) using joint time frequency analysis and multi-scale analysis feature. The given pulse was simulated based on wavelet transform. It was discussed that the influence of shaping factor to error of retrieval phase. The selecting principle of shape factor was determined. The characterization of Ti: sapphire laser was measured with SPIDER based on wavelet transform. The comparison with Fourier transform proves the precision of the above discussion.
The smoothness of the optical field on target surface in the laser inertial confinement fusion was studied based on fiber amplification network. The lens array was used to smooth the optical field generated by multi-beam multi-mode fiber laser after beam combining. The corresponding experiment was carried out with proper lens array. As a result, a small focused light spot was obtained on the target surface, with RMS less than 5% on the top region of the optical field. The influence of the target surface position and number of beam combining lasers on the smoothness of final optical field was also studied in the experiment. Proper target surface position and the increased number of beam combining lasers obviously improved the smoothness.
Eu3+ doped ZnO thin films fabricated on Si(111) by pulsed laser deposition were annealed in oxygen and vacuum. XRD spectra show that both the films are (002) oriented, which indicates that both the films are highly c-axis oriented. The structure parameters of the thin films show that the film annealed in oxygen ambient has bigger inter-planar space and smaller stress. When excited under the wavelength of 330 nm, the PL spectra exhibit two bands including a UV band and a DL band, and the ratio of IUV/IDL annealed in oxygen is larger. When excited under the wavelength of 395 nm, only obvious emission at the wavelength of about 595 nm was observed. The characteristic emission of 613 nm belonging to Eu3+ was not observed, which showed that the doped Eu3+ ion occupy inversion center.
The light field is periodic in the plane which is perpendicular with the direction of its propagation, and the diffraction field has a point-to-point correlation. On this basis, a high-order periodic diffraction correlation imaging scheme for reflective objects was presented. The performance of the proposed correlation imaging scheme was discussed by theoretical analysis and numerical simulation. The results show that the visibility of the periodic diffraction correlation imaging is enhanced while the signal-to-noise ratio is decreased with the larger order when the pinhole numbers of the pinhole array are determined. The visibility and signal-to-noise ratio are decreased with the pinhole number when the order numbers are determined. Compared with the traditional thermal correlation imaging, the scheme has advantages of size of the light source being controlled and the equipments of the experiment being simplified. Hence, it provides a reference method for the realization of correlation imaging.
Because the current of quantized mesoscopic RLC electric circuit can produce the Joule heat, quantum effects should be taken into account at finite temperature. In the equilibrium state of thermal environment, expected value of any mechanical quantity can be described by the ensemble average energy. Furthermore, using the technique of integration within ordered product(IWOP) of operator, the thermo-vacuum state was obtained in a quantized mesoscopic RLC electric circuit for the first time. Finally, by means of theoretical calculation, expected value of pure state at thermo-vacuum state was used to replace the ensemble average energy stored in the LC element and consumed in the R element.
Amplitude damping noise exists in many practical qubit systems with the loss of energy. The presentation of quantum Kraus operators of two-qubit system in amplitude damping channel was derived by using a common model in which two atoms are interacting with a single mode cavity resonantly. It provides a method by which concrete progress can be made on problems related to quantum information processing, such as bi-particle entanglement distribution and quantum error correction. Owning to its generality and convenience, this means is helpful to deal with real physical problems.
Considering a model containing two two-level atoms and a single-mode cavity, the effects of the time-dependent atom-field coupling on entanglement between the two atoms were researched when the two atoms are initially in an entangled state. The results show that, the time of initial entanglement preservation is very sensitive to the linear modulation of the atom-field coupling. Compared to the case of the constant coupling model, when the atom-field couplings change smoothly, the disappearance of the initial entanglement is delayed due to the linear modulation. However, the disappearance of the initial entanglement can be hastened for the sudden jump in the coupling.
A barrel shifter is a common component in the high-speed processor. It can shift a data word by specified number of bits in one clock cycle. Based on the quantum reversible logic circuit, the shifter with n inputs and m control bits named as a (n,m) shifter. For synthesizing the reversible shifter, the novel method based on the decomposition of the permutation group, it only use (3,1) shifters and controlled swap gates to quickly synthesize any controlled shifter with small quantum cost, and any (n,k) barrel shifter can be obtained by cascading minimal k corresponding (n,1) shifters.
The influence of the non-Markovian, dipole-dipole interaction of two atoms and the off-resonant on fidelity of two identity atoms’ quantum state was investigated by means of full quantum theory. The results show that the fidelity of two identity atoms’ quantum state is relatively higher when the two atoms are initially in the entangled state under the non-Markovian regime, especially in the off-resonant case, in which the fidelity considerably increases with interaction of the two atoms. If the two atoms are initially in the separable state, the fidelity of the quantum state is not optimal no matter the Markovian effect exists or not.
A quantum deterministic key distribution(QDKD) protocol was proposed by using W states as a carrier which is suitable for quantum channel transmission. Under the precondition of photon stability, using quantum correlations and a public string S as a key to key distribution, a high efficiency of 54.54% was reached just almost with GHZ states, and photons were transmitted with a stronger robustness. Security analysis results show that this protocol could resist two common attacks, ensure the communication safe and reliable. Meanwhile, this protocol doesn’t involve any unitary operation. It’s easy handling.
The relationship between the electrostatic field distribution and geometric parameters on the controllable electrostatic double-well was calculated and analyzed. The dependent relationship between the trapped central position and system parameters was also calculated and analyzed. The results show that position of the trapped center and depth of the trapped well can be changed by changing the scheme system parameters, thus the cold molecular can be obtained by the Stark deceleration, and even the higher temperature cold molecular trapping can be realized by selecting suitable system parameters.
The density of aerosol particles was explored by using particles size measurement. A differential mobility analyzer (DMA) was used to select a monodisperse particle population with specific mobility diameter. The monodisperse particles beam enter aerosol time-of-flight mass spectrometer (ATOFMS). According to the time of flights between the two optical detection stages individual particle vacuum aerodynamic diameter was measured. Together with the mobility and aerodynamic diameters the quantitative relationship between them was yielded. Then the particle density for spherical, ρp, or particle effective density for aspherical, ρeff, was obtained. A calibration experiment was carried out by using dioctyl phthalate (DOP), with known chemical composition and density, on the system. Then the system was used to measure the particle effective densities of ammonium sulfate, sodium chloride, ammonium nitrate. The results are 1.211 g/cm3, 1.333 g/cm3, 1.039 g/cm3, respectively. The particle density for spherical olive oil is 0.914 g/cm3.
The influence of phonon dispersion on properties of the magnetopolaron in a polar crystal was studied by using the linear combination operator and unitary transformation method. Taking account of the longitudinal optical (LO) phonon dispersion in a parabolic approximation, the ground state energy, self-trapping energy and ground state Landau energy of the magnetopolaron in a polar crystal as a function of coefficient of the phonon dispersion, cyclotron resonance frequency and electron-LO-phonon coupling constant were obtained. Numerical calculation results show that the ground state energy decreases with increasing the coefficient of the phonon dispersion and electron-LO-phonon coupling constant. The self-trapping energy increases with increasing the coefficient of phonon dispersion and the electron-LO-phonon coupling constant. The ground state Landau energy increases to a maximum and then fall with increasing the electron-LO-phonon coupling constant, and increases with increasing the coefficient of phonon dispersion.