2 W quasi-white-light based on idler-resonant optical parametric oscillation cascading sum-frequency generation with PPSLT

We present a high power red-green-blue (RGB) laser light source based on cascaded quasi-phasematched wavelength conversions in a single stoichiometric lithium tantalate. The superiority of the experimental setup is: the facula of the incident beam is elliptical to increase interaction volume, and the cavity was an idler resonant configuration for realizing more efficient red and blue light output. An average power of 2 W of quasi-white-light was obtained by proper combination of the RGB three colors. The conversion efficiency for the power of the quasi-white-light over pump power reached 36%. This efficiency and powerful RGB laser light source has potential applications in laser-based projection display et al.     

On learning process of a newsvendor with censored demand information

A behavioural study on the newsvendor problem without demand distribution knowledge or realized demands is conducted. We configure a censored-information scenario, where only sales data in history are provided. With laboratory experiments, we analyse participants ordering levels and ordering oscillations over time. It is observed that participants perform a significant learning process in the censored-information scenario. Moreover, we find that participants make orders by anchoring on the previous-period sales and adjusting to an adapted inventory level. On the basis of the observations, we propose an exponential-type learning (EXP) model to describe the behaviour of decision makers. Comparing with a chasing model that is popularly used in the full-information scenario, the EXP model is more recommended in the censored-information scenario.     

Color tuning of up-conversion emission in ytterbium,erbium, aluminum tri-doped zinc oxide crystal by adjusting aluminum concentration

Ytterbium, erbium, aluminum tri-doped zinc oxide crystal was synthesized, which can turn color from red to green up-conversion luminescence through adjusting aluminum content. When the aluminum concentration reached 4?mol%, the color of up-conversion emission first turn from red to green. Meanwhile, the ratio of red to green emission reduced from 25.32 to 0.26, and the coordinates of chromaticity coordinate calculation changes from (0.5749, 0.3378) to (0.2190, 0.7169) with aluminum concentration range from 0 to 4?mol%. The up-conversion emission peaks at 521, 542, and 660?nm of sample originate from the transitions of ²H_11/2 → ⁴I_15/2, ⁴S_3/2 → ⁴I_15/2, and ⁴F_9/2 → ⁴I_15/2 of erbium ions, respectively. X-ray diffraction patterns perform the better crystallization degree with increasing aluminum concentration. The scanning electron microscopy images show the porous and lamellar structures with different aluminum concentrations. A convenient but effective design to obtain ytterbium, erbium, aluminum tri-doped zinc oxide up-conversion luminescence is reported, which can turn color from red to green.     

Evaluation of simulated reservoirs by using the oblique-incidence reflectivity difference technique

正Dear Editors,The evaluation of the oil-gas resources’potential depends on the characterization of reservoirs.The geometry of the pore-crack structures and the compositions of the pore walls have influence on hydrocarbon production about capillarity and permeability[1].Besides,it has been known that the adsorption phenomenon in micro-structure plays a significant role in oil-gas reservoirs.Some techniques have been applied to characterize conventional and unconventional reservoirs,     

Effect of F-doping on the properties of LiFePO4-x/3Fx/C cathode materials via wet mechanical agitation-assisted high-temperature ball milling method

Journal of Solid State Electrochemistry - LiFePO4-x/3Fx/C (x = 0, 0.03, 0.06, 0.09) were obtained via wet mechanical agitation-assisted high-temperature ball milling method. XRD, SEM,...     

三阶柯西差分方程在几类群上的解

在几类群上讨论了三阶柯西差分方程解的存在性问题,将二阶柯西差分方程的已有结论进一步推广到三阶的情况,并给出在不同群上的一般解.     

Discovery of a new nontoxic cuprate superconducting system Ga-Ba-Ca-Cu-O

Superconductivity is observed in a new nontoxic cuprate system Ga-Ba-Ca-Cu-O,with T_c=82 K for Ga Ba_2Ca_5Cu_6O_(14+δ)(Ga-1256)and T_c=116 K probably for Ga Ba_2Ca_3Cu_4O_(10+δ)(Ga-1234)or Ga Ba_2Ca_2Cu_3O_(8+δ)(Ga-1223),respectively.All compounds are fabricated by solid state reaction method under high pressure and high temperature.Samples are characterized by resistivity,magnetization and X-ray diffraction(XRD)measurements.The temperature dependence of magnetization measured in both zero-field-cooled and field-cooled processes on one sample(S1)shows two superconducting transitions at about 82 K and113 K.The estimated shielding fraction for the phase with T_cof 82 K is about 67%,while the fraction for another phase with T_(c )of 113 K is quite small.The XRD Rietveld refinement for S1 indicates two main phases existing in the sample,Ga-1256 with fraction of about 58%and non-superconducting Ca_(0.85)Cu O_2with fraction of about 42%respectively.Thus,we can conclude the superconducting phase with transition temperature of 82 K is due to Ga-1256.The resistivity measurement also confirms the superconductivity for S1,and the resistivity reaches zero at about 82 K.The temperature dependence of magnetization for another sample(S2)shows much higher superconducting shielding fraction for the phase with T_cof 116 K,which may be a promising prospective for the synthesis of Ga-1234 or Ga-1223 phase.     

Investigating the Photostability of Quantum Dots at the Single‐Molecule Level

Quantum dots (QDs) have shown great potential to provide spatial, temporal, and structural information for biological systems. However, blinking, photobleaching, and spectral blueshift are adverse effects on their practical applications in biomedical research. An investigation of the effects of six reducing agents including cysteine (Cys), 1,4‐dithiothreitol (DTT), ethyl gallate (EG), L ‐glutathione (GSH), mercaptoacetic acid (MAA), and thiourea (TU) on the photostability of single QDs was studied. Our experiments demonstrate that both DTT and EG effectively inhibit blinking, photobleaching, and spectral blueshift. GSH molecules block blinking and photobleaching of QDs. The other reagents, Cys, MAA, and TU, only have the ability to counteract blinking. Possible explanations are given on the basis of research evidence. The results suggest possibilities for significant improvements in QDs for biological applications by adjusting the environmental conditions.