简易式多功能膛口装置结构及其性能指标的计算法

该文介绍一种被命名为内插管扩张型多功能膛口装置.其结构比较简单,且具有消焰、消声、制退和有利于提高射击精度多种功能.本装置各项性能指标的计算法,是采用实验与理论分析相结合建立的经验公式,既可用作正面计算,也可用作多目标函数综合优化设计的反面计算.     

The Main Progress of Perovskite Solar Cells in 2020–2021

Perovskite solar cells (PSCs) emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from ...     

Owl Shaped You

The Shang Dynasty(16th Century B.C.-11th Century B.C.)Height:20.5 cmBronzePreserved in Shanghai MuseumYou is a vessel to contain wine.This You is in the zoomorphic shape of two owls standing back to back.The cover is shaped as     

浅析《新功能主义及其后》的后实证主义研究方法

从社会学方法论的角度分析亚历山大在<新功能主义及其后>中所运用的后实证主义研究方法.在<新功能主义及其后>中,亚历山大力图重新建构帕森斯的结构功能主义理论传统并建立新的理论综合--新功能主义,为社会学界带来了一种新的理论发展趋势在批判实证主义和反实证主义认识论的基础上,主张在后实证主义认识论的基础上重建多维度的理论框架.     

In Vivo and In Vitro Degradation Behavior of Magnesium Alloys as Biomaterials

The corrosion behavior of pure Mg,AZ31,and AZ91D were evaluated in various in vitro and in vivo environments to investigate the potential application of these metals as biodegradable implant materials.DC polarization tests and immersion tests were performed in different simulated body solutions,such as distilled(DI) water,simulated body fluid(SBF) and phosphate buffered solution(PBS).Mg/Mg alloys were also implanted in different places in a mouse for in vivo weight loss and biocompatibility investigations.The in vivo subcutis bio-corrosion rate was lower than the corrosion rate for all of the in vitro simulated corrosive environments.The Mg/Mg alloys were biocompatible based on histology results for the liver,heart,kidney,skin and lung of the mouse during the two months implantation.Optical microscopy and scanning electron microscopy were carried out to investigate the morphology and topography of Mg/Mg alloys after immersion testing and implantation to understand the corrosion mechanisms.     

On the experimental and numerical investigation of clay/epoxy nanocomposites

Due to increasing use of clay/epoxy nanocomposites in industry, investigation of mechanical properties of clay nanocomposites has become of great interest. While the stiffening mechanism of clay nanocomposites is well documented, there is still not a clear understanding about how addition of clays affect the fracture behavior of clay/epoxy nanocomposites. The main aim of this paper is to measure and explain the effect of clays on ductility reduction of these nanocomposites. First, epoxy and clay/epoxy nanocomposites with different clay weight ratio were built. Then, the damage parameters of epoxy and clay/epoxy nanocomposites were measured by variation of the elasticity modulus. Based on loading–unloading experiments, the Lemaitre damage parameters for epoxy and clay/epoxy nanocomposites were extracted. Crack initiation and propagation in dog-bone sample were simulated for epoxy and clay/epoxy nanocomposites using the eXtended Finite Element Method (XFEM). The comparison between experimental and numerical results shows that the proposed method can predict the crack initiation location and propagation path in clay/epoxy nanocomposites.