We discover that the spatially coherent radiation within a certain frequency range can be obtained without common nonlinear optical process. Conventionally, emission spectra were by de-exciting excited centers from real energy levels to ground state. Our findings are achieved deploying high-entropy glass system (HEGS) doped with neodymium ions. The HEGS exhibits much broader infrared absorption than systems, which attributed high-frequency branch phonons or allowable multi-phonon processes...

The impact of a liquid droplet on solid surface is one the most common phenomena in nature and frequently encountered numerous technological processes. Despite significant progress understanding phenomenon over past century, dynamics, especially coupling effects between properties wettability process, still poorly understood. In this work, we experimentally investigated viscous droplets superamphiphobic surfaces, with viscosity liquids ranging from 0.89 to 150 mPa s. We showed that an...

We establish a unified framework for $L^2$ error analysis high order Lagrange finite volume methods on triangular meshes. Orthogonal conditions are originally proposed to construct dual partitions meshes, such that the corresponding method (FVM) schemes hold optimal norm convergence order. Moreover, with Aubin--Nitsche technique, we prove estimate FVM Some numerical experiments presented demonstrate proved result.

The modulated wideband converter (MWC) is an attractive analogue compressed sensing technique that has been proposed in recent years. Regrettably, the MWC high hardware complexity owing to its parallel channel structure. To reduce complexity, a novel compressive spectrum scheme based on single for band‐limited wide‐sense stationary (WSS) signals proposed. In scheme, special periodic waveform time domain designed and power model presented detect occupied frequency of such from sub‐Nyquist...

In a cognitive radio sensor network (CRSN), wideband spectrum sensing devices which aims to effectively exploit temporarily vacant intervals as soon possible are of great importance. However, the challenge increasingly high signal frequency and wide bandwidth requires an extremely sampling rate may exceed today’s best analog-to-digital converters (ADCs) front-end bandwidth. Recently, newly proposed architecture called modulated converter (MWC), is attractive analog compressed technique that...

The conditioning of the linear finite volume element discretization for general diffusion equations is studied on arbitrary simplicial meshes. condition number defined as ratio maximal singular value stiffness matrix to minimal eigenvalue its symmetric part. This definition motivated by fact that convergence rate generalized residual method corresponding systems determined ratio. An upper bound established developing an and a lower It shown depends three factors, elements in mesh, mesh...

Large Leidenfrost drops may be unstable when their diameters exceed a critical value. Through theoretical and experimental investigations, this study explored the feasibility of suppressing instability in large container, by meshing container or its central portion into rectangular elements. Thin rods were used to construct these was considered four configurations. They also mesh elements that might used. There two findings. First, diameter largest inscribed cylinder configuration dimension...

In this paper, we will analyze the Least Mean Square(LMS) and Recursive Square(RLS) algorithms. Then, apply these two algorithms to a Multiple-input Multiple-output(MIMO-OFDM) system based on Space-Time Block Coding(STBC), do some simulations From simulation, it is found that convergence speed of RLS algorithm faster than LMS algorithm, i.e., performance better algorithm.

A significant challenge to make learning techniques more suitable for general purpose use is move beyond i) complete supervision, ii) low dimensional data, iii) a single task and view per instance. Solving these challenges allows working with "Big Data" problems that are typically high multiple (but possibly incomplete) labelings views. While other work has addressed each of separately, in this paper we show how address them together, namely semi-supervised dimension reduction multi-task...

Leidenfrost drops have demonstrated promising applications in, for example, drag reduction. However, large may be unstable when their diameters exceed a critical value, leading to less control of such in applications. In this work, through theoretical and experimental investigations, the authors explore instability drop circular configuration, as well suppression using small rod. There are four findings. First, diameter largest inscribed cylinder inside rod–container configuration is...

颗粒物质在自然界和人类生产与生活中广泛存在，对于非规则颗粒，其宏观物理力学特性与几何形态密切相关。本文以本课题组和合作者的相关研究为基础，介绍了非规则颗粒几何形态的获取、重构、评价、随机生成以及离散元模拟方法等方面的研究进展。总结了非规则颗粒形态不同获取方法的优缺点；将颗粒二维形态和三维形态分别划分为星形和非星形两种类型，介绍了各类型几何形态的计算几何重构方法；系统总结了非规则颗粒不同层次形态评价指标的定义，及基于计算几何的指标计算方法；介绍了基于逆蒙特卡罗法的二维星形与三维星形随机颗粒生成方法，以及可考虑一阶系数固有关系和其它阶系数经验相关性的二维非星形与三维非星形虚拟颗粒生成方法；对于非规则颗粒的离散元模拟方法，重点总结了颗粒几何状态表示、颗粒接触判断与颗粒接触力计算方法等核心问题的研究进展。

Abstract Helical gears are widely used in mechanical devices, but insufficient tooth strength can easily lead to premature failure, which is an urgent problem be solved. To overcome this challenge, paper introduces a multi-objective particle swarm optimization algorithm, comprehensively considers the comprehensive effects of modification coefficient, number teeth, and modulus on performance helical gears. By constructing mathematical model with geometric parameters as core design variables,...

Abstract An axisymmetric two-phase lattice Boltzmann method is adopted to simulate the dewetting dynamics of liquid film on a substrate fabricated with different types roughness: pillar-type, nail-type and mushroom-type. The remains in Wenzel or half-Wenzel state. occurs after generating an initial dry spot forming contact line between film, gases substrate. characterized by continuous size growth line’s radius. effect geometric factors roughnesses analyzed detail. For pillar-type roughness,...

For high power and repetitive Nd:Glass laser, there would appear serious thermal effect due to the significantly-enhanced pumping optical density in laser rod, which induce double refraction, phase distortion, focusing, depolarization, etc. Thus, output beam quality be influenced severely. Influence of lens depolarization caused by stress refraction on were studied this paper for laser. In experiment effect, change spot was recorded after a TEM00 He-Ne passing through rod pumped Xe lamp,...