Effects of Sr2+ substitution on the crystal structure,Raman spectra,bond valence and microwave dielectric properties of Ba3-xSrx(VO4)2 solid solutions

The effects of Sr²⁺ substitution for Ba²⁺ on microwave dielectric properties and crystal structure of Ba_3-xSr_x(VO₄)₂ (0 ≤ x ≤ 3, BSVO) solid solution were investigated. Such Sr²⁺ substitution contributes to significant reduction in sintering temperature from 1400 °C to 1150 °C. Both permittivity (∑_r) and quality factor (Q × f) values decreased with increasing x value, which was determined to be related with the descending values of average polarizability and packing fraction, whereas the increase in τ_f value was explained by the decreased average VO bond length, A-site bond valence. BSVO ceramics possessed encouraging dielectric performances with ∑_r = 12.2–15.6 ± 0.1, Q × f = 44,340 - 62,000 ± 800 GHz, and τ_f = 24.5–64.5 ± 0.2 ppm/°C. Low-temperature sintering was manipulated by adding B₂O₃ as sintering additive for the representative Sr₃V₂O₈ (SVO) ceramic and only 1 wt.% B₂O₃ addition successfully contributed to a 21.7% decrease in sintering temperature to 900 °C, showing good chemical compatibility with silver electrodes, which render BSVO series and SVO ceramics potential candidates in multilayer electronic devices fabrication.     

The co-location of innovation and production in clusters

ABSTRACT

This paper quantifies the extent of co-location of innovation and production for industry clusters with varying knowledge intensity. If input-output, knowledge, and skill linkages are interdependent and geographically bounded, then we would expect innovation and production to be co-located in regional clusters. However, theory predicts that the degree of agglomeration benefits associated with co-location may vary across economic activities with different knowledge intensity. Using data from the U.S. Cluster Mapping Project, I develop measures of the co-location of innovation and production for 27 industry clusters, examining patterns across regions and over time (1998–2015) in the United States. I find that there is a significant co-location of innovation and production for many clusters, especially for those with higher knowledge intensity. This paper focuses on the Information Technology and Analytical Instruments cluster and the Automotive cluster to illustrate the co-location measures and the micro-geography of innovation and production.     

10710工作面灰岩探查孔出现问题分析

针对10710工作面机巷施工灰岩探查孔过程中出现的问题,从底板岩层应力分布状态方面分析,寻找钻孔变形的原因,提出防治措施,避免类似事故发生。     

弧齿式与锯齿式接链环的比较

分析了锯齿式接链环结构的不合理性和其换代产品弧齿式接链环结构的合理性,并对两者的技术性能、使用寿命等进行了比较分析,认为弧齿式接链环具有较高的破断强度和疲劳强度,是目前井下使用的接链环更新换代的最佳产品。     

利用惯性圆锥破碎机降低入磨粒度的研究

简述了惯性圆锥破碎机的结构和特点,并通过惯性圆锥破碎机应用实例表明该机能有效降低入磨粒度,优化选厂破碎工艺流程,很好地满足"多碎少磨"新工艺的要求。     

铁坑褐铁矿选矿新工艺研究

通过对江西铁坑褐铁矿选矿试验研究和生产实践分析，阐明褐铁矿的选矿技术及发展。     

推广应用新型模板和脚手架需解决的几个问题

目前新型模板和脚手架在推广应用过程中出现的一些问题，如标准制订和颁布严重滞后，代低省产品流入市场等，对此提出了解决这些问题的途径和措施。     

船屋文化：海南黎族传统民居探源

从文化心理行为模式的角度对黎族民居空间及造型形成过程进行了探讨。认为人类在塑造自己生存立足的场所时一直伴随着对意义的追求，人赋予建筑的表征意义在很大程度上决定了建筑空间及造型的可识别性特性，构成了场所感，成为特定地域、特定场所的一种文化“原型”识别性标志。     

观察的向度--仙乐斯广场之建筑观察

文章从视距、角度、架构、片断及层面等方面对仙乐斯广场进行了建筑体验和观察开拓了建筑观察的新视野。