Quadratic Growth Conditions and Uniqueness of Optimal Solution to Lasso

Journal of Optimization Theory and Applications - In the previous paper Bello-Cruz et al. (J Optim Theory Appl 188:378–401, 2021), we showed that the quadratic growth condition plays a key...     

Kurdyka–Łojasiewicz Exponent via Inf-projection

Foundations of Computational Mathematics - Kurdyka–Łojasiewicz (KL) exponent plays an important role in estimating the convergence rate of many contemporary first-order methods. In...     

关于最小不确定态的概率分布

本文借助于曲线坐标下动量算符的一种厄密形式,导出了广义坐标算符和广义动量算符的最小不确定态,并结合常见坐标分量取不同上、下限的情况讨论相应的概率分布,进而得到有关的结论.     

Nature of the high-pressure transition in Fe2O3 hematite

We present a new method to separate the crystallographic and electronic phase transitions in hematite using x-ray emission spectroscopy and x-ray diffraction. Our observations, based on the behavior of a metastable high-pressure phase in the stability domain of the low-pressure phase, show that the electronic transition is preempted by the crystallographic transition. The former occurs only afterwards in the high-pressure phase, possibly as a result of a Mott transition. The idea that the electronic transition drives the transition in hematite is therefore invalidated. Such methods should help elucidate the mechanics and the driving forces behind a number of first-order high-pressure phase transitions.     

充水圆柱壳声散射的环绕波分析

研究了内部充水圆柱壳散射声场的构成。采用弹性薄壳理论和Sommerfeld-Watson变换(SWT)方法导出散射声场的解析解。数值搜索环绕波的复波数极点,比较圆柱壳体内部真空和内部充水两种情况下表面环绕波的相速度、衰减等性质。用镜反射波和环绕波的叠加合成反向散射形态函数,与简正级数解符合良好。计算流体附加环绕波的回波时序并与实验数据对照。结果表明,流体附加环绕波的再辐射是内部充水圆柱壳的形态函数出现更加丰富的共振峰和回波结构形成的重要原因。     

外部加环肋有限长圆柱壳体声散射

为了深入理解双层加肋圆柱壳体的声散射机理,专门研究了两层壳体之间环肋的声散射。仅考虑模型的刚性散射,采用Kirchhoff近似推导了单个环肋的反向散射声场的解析解,并推广到等间距的环肋散射,结合圆柱壳刚性散射得到外部加周期性环肋的圆柱壳体的散射声场近似解。同时,利用图形声学方法(GRACO)对模型的目标强度进行数值计算。理论与实验的结果表明,刚性散射在反向散射声场中起主要作用,周期性环肋引起的Bragg散射对散射声场有重要贡献,同时遮挡效应在实际情况下有较大作用。