Luminescent properties of Dy doped SrMoO4 phosphor

Trivalent dysprosium ions (Dy³⁺) doped strontium molybdate (SrMoO₄) phosphors were synthesized by solid-state reaction and their photoluminescence (PL) properties were investigated. X-ray powder diffraction (XRD) analysis confirmed the formation of SrMoO₄:Dy³⁺. PL measurements indicated that the phosphor exhibited intense emission at 482, 490 (⁴F_9/2→⁶H_15/2) and 575 nm (⁴F_9/2→⁶H_13/2) under UV excitation. The effect of the doping concentration of Dy³⁺in SrMoO₄:Dy³⁺ on the PL was investigated in detail. Na⁺ ion was a good charge compensator for SrMoO₄:Dy³⁺.     

Oxygen relaxation and phase transition in GdBaCo2O5 + δ oxide

Electrical conductivity, internal friction techniques and dilatometer have been used to investigate the oxygen relaxation, phase transition and thermal expansion behavior of GdBaCo₂O_5 + δ. The main electronic charge carriers in GdBaCo₂O_5 + δ are electronic holes, which could be assigned to the formation of Co⁴⁺. The oxygen exchange kinetics intensely depends on oxygen partial pressure and is also closely related to temperature. Both electrical conductivity and internal friction give rise to an abnormal at about 75 °C, which are related to the insulator-metal transition occurring in GdBaCo₂O_5 + δ. One large relaxation internal friction peak, due to the motion of oxygen within Gd-O plane, is also found in the oxide. The average thermal expansion coefficient (TEC) of GdBaCo₂O_5 + δ is about 21.4 × 10⁻⁶ K⁻¹ between 500 °C and 900 °C.     

Oscillatory expression and variability in p53 regulatory network

The effect of delay, nonlinearity and noise on oscillatory motion is of permanent interest for theoretical and experimental research. Here we explore a negative feedback loop between p53 and Mdm2 with a time delay, which is a key circuit in the response of cells to damage. This circuit shows noisy sustained oscillations in individual human cells following DNA damage, and damped oscillations at the cell population level. We demonstrate the effect of delay on the oscillation, and the correlation in time course. In a multi-species system, the events at different time points which span a time delay are coupled even when the delay is large compared with the other characteristic times of the system. We also clarify that the dynamics at the single-cell level appears to be coherent resonance, and the origin of the damped oscillation at the macroscopic level out of the sustained ones at the single-cell level can be ascribed to the dephasing process which is induced by the interplay between nonlinearity and noise. The findings are consistent with experimental observations and advance our understanding of the dynamics of the p53 network.     

角分辨光电子能谱光束线1200line/mm光栅研制

国家同步辐射实验室新建了覆盖5～40 eV的低能区高分辨率角分辨光电子能谱光束线.其球面光栅单色仪包含了三块光栅,即300,600和1200 line/mm球面层式(Laminar)光栅.采用全息离子束刻蚀工艺,在硅光栅基片上成功地刻蚀出1200 line/mm、占空比0.35、槽深35 nm、有效刻划面积大于120 ...     

A New Strategy to Identify and Eliminate the Inner Filter Effects by Outer Filter Technique

To identify and eliminate the inner filter effects (IFEs), prepositive and side cells containing absorbents are fixed beside the fluorescer contained cell. In this way, excitation and emission lights can be quenched by primary and secondary outer filter effects respectively, depending on absorbent concentration and cell length. Herein the quenching of emission fluorescence caused by IFEs can be equally reduced by outer filter effects (OFEs) and the interference of IFEs was eliminated. This approach was experimentally used for identifying the interaction mode and mechanism between BSA and nanoAg. Results showed that the quenching of BSA fluorescence and synchronous fluorescence mainly attributes to IFEs, instead of static/dynamic fluorescent quenching. In view of the above, the elimination of the interference of IFEs by the design of OFEs plays an important part in the precise application of fluorescence detector.     

Maskless laser tailoring of conical pillar arrays for antireflective biomimetic surfaces

Herein, we report a facile approach for rapid and maskless production of subwavelength structured antireflective surfaces with high and broadband transmittance-direct laser interference ablation. The interfered laser beams were introduced into the surface of a bare optical substrate, where structured surfaces consisting of a micropillar array were produced by two-step laser irradiation in the time frame of seconds. A multiple exposure of the two-beam interference approach was proposed instead of multiple-beam interference to simply realize planar patterns of a high aspect ratio. Tall sinusoidal pillars were created and shaped by pulse shot number control. As an example of the application, zinc sulfide substrates were processed with the technology, from which high transmission at an infrared wavelength, over 92%, at normal incidence was experimentally achieved.     

Cu-In-O composite thin films deposited by reactive DC magnetron sputtering

Cu-In-O composite thin films were deposited by reactive DC magnetron sputtering at room temperature. The samples were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV/vis spectrophotometer, four-probe measurement and Seebeck effect measurement, etc. The samples contain Cu, In and O. The ratios of Cu to In and O to In increase with increase in O₂ flow rates. The ratio of Cu to In is over 1 and this suggests that Cu is in excess. The obtained Cu-In-O thin films are very possibly made of rhombohedral In₂O₃ and monoclinic CuO. Transmittance of the films decreases with increase in O₂ flow rate. The decrease in transmittance results from increase in Cu content in the films. The optical band gap of all the samples is estimated to be 4.1-4.4 eV, which is larger than those of In₂O₃ and CuO. The sheet resistance of the films decreases with increase in O₂ flow rate. Conductivity of the films is a little low, due to the addition of Cu and the poor crystalline quality of the film. The conduction behavior of the films is similar to that of In₂O₃ and the conduction mechanism of Cu-In-O thin films is through O vacancy.     

Above-threshold detachment of negative ions by circularly polarized few-cycle laser fields

In accordance with nonperturbative quantum scattering theory,we investigate photoelectron angular distributions(PADs) from above-threshold detachment(ATD) of negative ions irradiated by circularly polarized few-cycle laser fields.Electrons ejected on the polarization plane demonstrate distinct anisotropies in angular distributions which distinctly vary with the carrier-envelope(CE) phase.The anisotropy is caused by interference between transition channels;it also depends strongly on laser frequency,pulse duration,and kinetic energy of photoelectrons.Optimal emission of photoelectrons,which varies with CE phase,makes it possible to control photoelectron motion.     

Passive picosecond and femtosecond mode-locking laser action of Yb<Superscript>3+</Superscript>:LuYSiO<Subscript>5</Subscript>

Efficient passive mode locking of a diode-pumped Yb³⁺:LuYSiO₅ (Yb:LYSO) laser is first demonstrated in experiment using a semiconductor saturable absorber mirror (SESAM), to the best of our knowledge. A stable pulse train with a repetition rate of 101 MHz is generated. The average output power of 2.13 W and the pulse duration of 3.9 ps. With a pair of SF10 uncoated prisms for dispersion compensation, we obtained pulses as short as 780 fs with center wavelength around 1042 nm, the average output power of 1.03 W and the peak power of 13.1 kW.     

Cooling of a <Emphasis Type="Italic">Λ</Emphasis>-type three-level atom in a high-finesse optical cavity

A theoretical study is carried out for the cavity cooling of a Λ-type three-level atom in a high-finesse optical cavity driven by a weakly field. Analytical expressions for the friction, diffusion coefficients and the equilibrium temperature are obtained by using the Heisenberg equations, then they are calculated numerically and shown graphically as functions of the controlling parameters. For a suitable choice of these parameters, the dynamics of the cavity field interaction with the Λ-type three-level atom introduces a sisyphus cooling mechanism yielding lower temperature than the one of the two-level atom, avoiding the problems induced by spontaneous emission.