Experimental study of wave propagation characteristics on a simplified coral reef

The wave transformation over slope topography is widely studied,but most of studies are for common coastal slopes.This paper presents an experimental study of 2-D regular and irregular wave transformations on a simplified coral reef with a steep slope of 1:5 and a horizontal reef flat,focusing on the characteristics of the waves that break on the reef flat.The analyzed results show that the estimates of the wave breaking made by using the well-known previous formulae do not agree completely with the experimental results.When the waves break on a reef flat,the relative breaking wave height(H/d)b is related to the incident deep-water wave steepness and the relative water depth db/L0.Hence,a new criterion for breaking waves on a reef flat is proposed.Furthermore,in view of the fact that the local Ursell number is commonly used to parameterize the wave nonlinearity,the relationships among the skewness,the asymmetry,and the local Ursell number are also presented.Experimental data confirm that when the Ursell number is greater than 30,the absolute values of the skewness and the asymmetry on a reef flat are greater than those on a steep slope.

Dynamic entanglement for continuous variables in an electric field background

Quantum entanglement is a typical nonclassical correlation.Here,we use this concept to analyze quantum entanglement for continuous variables generated by the Schwinger pair production for constant and pulsed electric fields.An initial two-mode entangled state evolves into a three-mode entangled state through a Gaussian channel of the Schwinger effect,which encodes the information about the Schwinger effect.By detecting the entanglement of the output three-mode state,we obtain the optimal parameters for easier to generate particle-antiparticle pairs.We find that the generated 1→2 entanglement is more sensitive to the parameters than the generated 1→1 entanglement.Therefore,we should choose the generated 1→2 entanglement to extract information.We argue that extracting the optimal parameters from quantum entanglement may guide future experiments.

Structure-based design,synthesis,and biological evaluation of novel pyrimidinone derivatives as PDE9 inhibitors

The pathological processes of Alzheimer's disease and type 2 diabetes mellitus have been demonstrated to be linked together. Both PDE9 inhibitors and PPARγ agonists such as rosiglitazone exhibited remarkable preclinical and clinical treatment effects for these two diseases. In this study, a series of PDE9 inhibitors combining the pharmacophore of rosiglitazone were discovered. All the compounds possessed remarkable affinities towards PDE9 and four of them have the IC_(50) values 5n mol/L. In addition, these four compounds showed low cell toxicity in human SH-SY5Y neuroblastoma cells.Compound 11a, the most effective one, gave the IC_(50) of 1.1 nmol/L towards PDE9, which is significantly better than the reference compounds PF-04447943 and BAY 73-6691. The analysis of putative binding patterns and binding free energy of the designed compounds with PDE9 may explain the structure–activity relationships and provide evidence for further structural modifications.

斜坡地形上正向、斜向和多向不规则波统计特征参数研究

目前,大多数关于斜坡地形上波浪统计特征参数的研究都是基于正向入射规则波或不规则波进行的。该文通过物理模型试验,对正向、斜向和多向不规则波在1:15斜坡地形上基于谱矩描述的波浪破碎指标以及波浪的统计特征参数进行了研究。研究结果表明,在该试验条件下,斜向不规则波的破碎指标略大于正向不规则波,而多向不规则波的破碎指标可以采用正向不规则波的拟合结果;波浪的入射方向和方向分布对各特征波高与√m_(0)(m_(0)为波浪频谱的零阶矩)的比值、各特征波高之间的比值以及不对称度、偏度和峰度的影响不大。另外,给出了该斜坡上不对称度和偏度与Ursell参数的关系以及偏度与峰度的关系。