Effects of multi-Schell beams on orbital angular momentum of entangled signal photons in low-order turbulence aberration channels

We model the detection and crosstalk probability of orbital angular momentum (OAM) states of the entangled signal photon in the Kolmogorov channels of the low-order turbulence aberrations and by the Rytov approximation. The results show that lower OAM mode number of signal photons and larger sub-beam number of multi-Gaussian Schell-model pump beam, the less susceptible of the detection probability of the signal photon to spatial coherence of source and turbulence aberrations is achieved. The maximum crosstalk probability is decrease as the decreasing of the sub-beam number of multi-Gaussian Schell-model. Enlarging OAM difference value or decreasing sub-beam number of multi-Gaussian Schell-model pump beam results in a lower crosstalk probability of the OAM of entangled signal photons.     

Direct and adjoint global stability analysis of turbulent transonic flows over a NACA0012 profile

In this work, various turbulent solutions of the two‐dimensional (2D) and three‐dimensional compressible Reynolds averaged Navier–Stokes equations are analyzed using global stability theory. This analysis is motivated by the onset of flow unsteadiness (Hopf bifurcation) for transonic buffet conditions where moderately high Reynolds numbers and compressible effects must be considered. The buffet phenomenon involves a complex interaction between the separated flow and a shock wave. The efficient numerical methodology presented in this paper predicts the critical parameters, namely, the angle of attack and Mach and Reynolds numbers beyond which the onset of flow unsteadiness appears. The geometry, a NACA0012 profile, and flow parameters selected reproduce situations of practical interest for aeronautical applications. The numerical computation is performed in three steps. First, a steady baseflow solution is obtained; second, the Jacobian matrix for the RANS equations based on a finite volume discretization is computed; and finally, the generalized eigenvalue problem is derived when the baseflow is linearly perturbed. The methodology is validated predicting the 2D Hopf bifurcation for a circular cylinder under laminar flow condition. This benchmark shows good agreement with the previous published computations and experimental data. In the transonic buffet case, the baseflow is computed using the Spalart–Allmaras turbulence model and represents a mean flow where the high frequency content and length scales of the order of the shear‐layer thickness have been averaged. The lower frequency content is assumed to be decoupled from the high frequencies, thus allowing a stability analysis to be performed on the low frequency range. In addition, results of the corresponding adjoint problem and the sensitivity map are provided for the first time for the buffet problem. Finally, an extruded three‐dimensional geometry of the NACA0012 airfoil, where all velocity components are considered, was also analyzed as a Triglobal stability case, and the outcoming results were compared to the previous 2D limited model, confirming that the buffet onset is well detected. Copyright © 2014 John Wiley & Sons, Ltd.     

Eulerian spatial and temporal autocorrelations: assessment of Taylor's hypothesis and a model

We present measurements of Eulerian longitudinal velocity autocorrelations in homogeneous, isotropic, high-intensity (～9%) free-stream turbulence behind an active grid. Spatial correlations are measured using particle image velocimetry as well as with two-point hot-wire anemometry (HWA), while temporal correlations are measured using HWA. The temporal correlations are transformed into spatial correlations by using Taylor's ‘frozen’ hypothesis with both the mean as well as instantaneous velocities. A model relating Eulerian spatial and temporal autocorrelations is also used for this purpose. The differences from the measured spatial correlation resulting from the use of Taylor's hypothesis on the temporal correlation is quantified; even at this moderately high level of turbulent intensity, the result from the use of the instantaneous velocity as convection velocity is practically indistinguishable from that obtained using the mean velocity. Use of the model produces a good agreement between the estimates of the spatial correlation function. A relation between Eulerian spatial and temporal integral scales is also derived.     

Green ultra‐fast high‐performance liquid chromatographic method using a short narrow‐bore column packed with fully porous sub‐2 μm particles for the simultaneous determination of selected pharmaceuticals as surface water and wastewater pollutants

Fast separations are very desirable in laboratories that analyze large numbers of samples per day or those needing short turn‐around times. Traditional HPLC methods using conventional stationary phases and standard column dimensions require significant amounts of organic solvents and generate large volumes of waste. With growing awareness about the environment, the development of green technologies has been receiving increasing attention. In this work, a very fast green analytical method based on LC‐UV using a short narrow bore column packed with fully porous sub‐2 μm particles has been developed for simultaneous determination of nine pharmaceuticals in wastewater and surface water. The chromatographic separation was optimized in order to achieve short analysis time and good resolution for all analytes in a single run. All analytes could be separated in 1 min with good resolution. Sample preparation was executed by solid phase extraction using Oasis HLB cartridges. The method developed was validated based on parameters such as linearity, precision, accuracy, detection, and quantification limits. The recovery ranged from 70.9 to 92.5% with SDs not higher than 5.4%, except for acetaminophen and sulphanilamide. LODs ranged from 0.6–2.5 μg/L, while the LOQs were in the range 2–8 μg/L.     

Experimental investigation of fully developed falling film flow in the presence of conduction pumps

Conduction pumping is appropriate way for liquid pumping due to its benefits like being noise free and easy controlling. In the present work fully developed falling film flow in the presence of conduction pumps has been experimentally investigated. Two different arrangements were selected and Transformer oil was used. Results indicated that, applying electric field would decrease thickness of falling film in wide range of Re number. The variation of wave's frequency and velocity regarding to Re number is also presented and compared for arrangements. Conduction pumps increased wave's frequency at low Re numbers conversely decreased it at high Re numbers.     

AuQ+碰撞氦原子单电离的全微分截面

利用三体扭曲波计算了3.6 MeV/amu的Au^Q+ (Q=24,53)碰撞氦原子单电离的全微分截面,其结果与实验数据和其它理论进行了比较,表明全微分截面受到高电荷入射粒子的强烈影响,敲出的电子被“拖拽”沿着向前的方向. 但是,所有的理论结果都不能呈现实验上全微分截面的独特的向前峰.     

Analysis of marine atmospheric turbulence effects on infrared imaging system by angle of arrival fluctuations

For the long-range infrared imaging system, the marine atmospheric turbulence degrades seriously the probability of object recognition and tracking. In this study, the angle of arrival fluctuations of an optical wave, which describes the distortion effects of marine atmospheric turbulence on an infrared optical imaging system, is investigated in detail both analytically and numerically. Analytic expressions of the angle of arrival fluctuations are derived for optical plane and spherical waves propagating through weak marine atmospheric turbulence with horizontal path, and they consider simultaneously finite turbulence inner scale, turbulence outer scale, wavelength, and aperture diameters. Numerical calculations are conducted to analyze the influence of marine weak turbulence on the infrared imaging. The results are useful for understanding the potential impact of deviations from the terrestrial turbulence.     

Automatic analysis of microscopic photo-pictures of undeveloped and developed nuclear emulsions

Methods of automatic computer analyses of images have large impotence in numerous physical problems with different kinds of radiations, which use such solid-state detectors as nuclear photographic emulsions, plastics and others. We described a method of expanding boundaries of dark areas for such computer analyses of micro-pictures. We demonstrated effectiveness of this method by the example of the search of microcrystals size distributions in two undeveloped nuclear emulsions and similar distribution of background grains in the developed emulsion.     

超声心动图联合动态心电图检查对急性心肌梗死诊断和预后评估的价值

为探讨超声心动图联合动态心电图检查在急性心肌梗死(AMI)患者诊断和预后评估中的应用价值,本研究选取2016年6月~2018年6月我院收治并确诊的100例AMI患者作为观察组,另选取同期100例非冠心病患者作为对照组。以AMI患者心源性死亡为终点事件,将观察组分为死亡组(n=15)和存活组(n=85)。所有患者均采用飞利浦IU-Elite及EPIQ5彩色多普勒超声诊断仪进行超声心动图检查,采用DMS-3004A进行标准的12导联动态心电图检查。比较各组患者心率震荡指标[震荡起始(TO)、震荡斜率(TS)]、心率变异性指标[NN间期标准差(SDNN)、QT离散度(QTd)、经心率校正的QT离散度(QTcd)]及心功能指标[左心室舒张末期内径(LVEDD)、左心室射血分数(LVEF)]水平的变化。结果显示,观察组TO、QTd、QTcd、LVEDD均明显高于对照组,TS、SDNN、LVEF均明显低于对照组,差异有统计学意义(P<0.05)。死亡组TS、SDNN均明显低于存活组,差异有统计学意义(P<0.05);死亡组TO高于存活组,QTd、QTcd、LVEF、LVEDD均低于存活组,但差异无统计学意义(P>0.05)。本研究结果表明,AMI患者心率震荡(HRT)明显减弱甚至消失,HRV、LVEF明显降低,LVEDD、QTd明显增大,QT间期明显延长。超声心动图和动态心电图联合检查对AMI患者诊断及预后评估均有重要的临床应用价值。