Driver Countries in Global Banking Network

We analyze the network of cross-border bank lending connections among countries from 1977 to 2018. The network includes core countries that lend money and peripheral countries that borrow money from core countries. In nowadays highly connected banking network, financial crisis that start from a country can spread to other countries very fast and cause global affects. We use principal component analysis (PCA) to find the influential lending (core) countries in this network over the years and clusters of borrowing (peripheral) countries related to these impactful core countries. We find three clusters of peripheral countries, with some constant and some changing members over time. This can be a sign of changes in the financial or political interactions among countries. The changes in the role of core countries and how these roles get affected by the important financial crisis in the past decades is investigated. Among 31 of core countries, 7 countries have a partially or constantly important role in the network including France, United Kingdom, United States, Japan, Germany, Chinese Taipei and Switzerland.     

Investigation on ultrasonic cavitation erosion of TiMo and TiNb alloys in sulfuric acid solution

Two kinds of Ti-alloys, i.e., TiMo and TiNb alloys are manufactured in this paper, and their ultrasonic cavitation erosion behaviors in 0.1 M H₂SO₄ solution are evaluated by the mean depth erosion (MDE), SEM and white light photograph. The results show that MDE of TiMo and TiNb alloys obviously increase with increasing the cavitation erosion time, however, they evidently decrease with the increment of Mo or Nb content at each fixed cavitation erosion time, and even some large blank areas (uneroded areas) still exist on the sample surface after ultrasonic cavitation erosion for 2 h in the case of Ti10Mo and Ti20Nb samples, implying the enhanced anti-cavitation erosion property of Ti-alloy by adding Mo or Nb element. The MDE of Ti10Mo or Ti20Nb sample is lower than that of TC4 sample in the case of each cavitation erosion time, indicating the better cavitation erosion resistance of of Ti10Mo or Ti20Nb sample. The influences of Mo and Nb on the passivity of TiMo and TiNb alloys during the ultrasonic cavitation erosion are detected by potentiodynamic curves. The results display that Ti, TC4, TixMo (x = 1, 5, 10) and TixNb (x = 5, 10, 20) samples are all almost in the passive state within the potential region from 0V_SCE to 1.5V_SCE during ultrasonic cavitation erosion, and the passive current density evidently decreases with increasing Mo or Nb content, indicating the enhanced passive characteristic by adding Mo or Nb alloys during the ultrasonic cavitation erosion.     

Synergistic enhancement of vinyltriethoxysilane and layered Mg–Al double hydroxide on the tracking and erosion resistance of silicone rubber

It is of great significance and challenge to efficiently improve the tracking and erosion resistance of silicone rubber along with the growing requirements in the field of outdoor high voltage insulation. In this work, we herein proposed an effective way to address this issue by incorporating vinyltriethoxysilane (ViTES) and layered Mg–Al double hydroxide (LDH) into high temperature vulcanized silicone rubber (HTVSR). ViTES/LDH notably enhanced the tracking and erosion resistance of HTVSR. With addition of 3.33 phr ViTES and 5.00 phr LDH, the anti-tracking performance of HTVSR reached the 1A 4.5 level, and the eroded mass was merely 0.3%. The results of scanning electron microscopy and equilibrium swelling showed that ViTES substantially improved the interfacial interaction between HTVSR and LDH and the crosslinking density of HTVSR, and enhanced the dispersion of LDH sheets in the HTVSR matrix. The possible synergistic suppression mechanism of ViTES/LDH on the tracking and erosion of HTVSR was further studied and demonstrated by the plasma irradiation analysis, thermogravimetry and thermogravimetry-Fourier transform infrared spectrometry. It was indicated that under the high voltage arcing discharge, LDH facilitated the formation of a dense barrier layer consisting of bimetal mixed oxides on the HTVSR surface, exerting outstanding lamellar barrier effect. The further degradation and the generation as well as development of electrical tracking were efficiently suppressed. Our findings provided a new approach to fabricate silicone rubber with excellent tracking and erosion resistance.     

南京市区建筑场地地下水腐蚀性评价

本文介绍南京市区地下水的化学成分和建筑场地地下水腐蚀性评价以及腐蚀性原因分析。     

液滴与可变形固面撞击的二维非线性激波模型

在传统的关于液固撞击的激波理论模型中，引入矢量分析的方法，考虑到高速度撞击时，液体运动的迁移性和非线性效应，以及固体的可变形性，提出了一个适用于高撞击马赫数的无量纲激波理论模型。该模型能够计算出所有撞击参数，计算结果与实验数据吻合良好。模型所导出的计算方法物理意义明确，简明准确，适用范围宽广，且便于工程上制成图表查用。     

Influences of Slope Gradient on Soil Erosion

ＩｎｔｒｏｄｕｃｔｉｏｎＳｏｉｌｅｒｏｓｉｏｎｃａｎｂｅｃｌａｓｓｉｆｉｅｄｉｎｔｏｍａｎｙｔｙｐｅｓｄｕｅｔｏｄｉｆｆｅｒｅｎｔｅｒｏｄｉｎｇｆｏｒｃｅｓ .Ａｍｏｎｇｔｈｅｍｔｈｅｓｕｒｆａｃｅｒｕｎｏｆｆｅｒｏｓｉｏｎｉｓｔｈｅｃｏｍｍｏｎｅｓｔｏｎｅ .Ｔｈｅｓｌｏｐｅｇｒａｄｉｅｎｔｉｓｏｎｅｏｆｔｈｅｍｏｓｔｉｍｐｏｒｔａｎｔｆａｃｔｏｒｓａｆｆｅｃｔｉｎｇｔｈｅｓｕｒｆａｃｅｆｌｏｗｅｒｏｓｉｏｎ .Ｕｎｄｅｒｔｈｅｓａｍｅｒａｉｎｆａｌｌｃｏｎｄｉｔｉｏｎ ,ｔｈｅｓｕｒｆａｃｅｆｌｏｗ…     

关于跃移沙破坏生物结皮时的临界速度的理论分析

利用经典的弹性薄板与塑性理论探讨了生物结皮在单颗跃移沙粒碰撞作用下的破坏问 题,建立了一个联结跃移沙粒的临界撞击速度和结皮性质的解析关系式. 种类、数量、发展 阶段等生物效应主要通过结皮的杨氏模量、Possion比、屈服应力等宏观参量引入. 结果表 明,刚度大、强度低的生物结皮更容易被跃移沙粒所破坏. 给出的关系式将有助于进一 步研究风沙运动和结皮之间的相互作用.     

气固两相流风机的三元计算与二元计算的比较

在单相耦合模型的基础上，采用合适的粒子反弹模型和磨损模型，分析、推导、编制了三元粒子运动、碰撞的程序，并与二元粒子程序进行了比较，验证了该三元程序的优越性，为气固两相流离心风机叶轮的研制提供了一个行之有效的理论工具。     

我国标准物质的管理及其发展

阐述了我国标准物质的分类、分级、编号及其管理。描述了标准物质的溯源体系及定值的组织系统,介绍了国际标准物质信息库。