Results 81 to 90 of about 13,988 (180)
Synthesis and Characterization of the Novel Transition-Metal Fluorine-Containing Phosphates and Borophosphates [PDF]
, 2016 一维管状结构的材料凭借其独一无二的结构和优良的性能现已成为材料领域的研究热点，例如典型的一维管状材料碳纳米管在催化、吸附、储氢等领域都有着极大的潜在应用价值。由此，本文致力于合成一维管状材料。通过调控反应体系中的原料配比，成功将氟离子引入晶体结构，合成出具有孤立的一维管道结构的新型铁氟磷酸盐晶体，该结构十分罕见。氟的引入，为合成低维度的高化合价过渡金属氟磷酸盐提供了一种新思路。 （1）本文首先通过水热法合成铁磷酸盐SrFeH(PO4)2(H2O)x(x≈0~0.5)，该化合物的晶体结构为二维层状结构 ...
陈婷荷
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Rare Metals, EarlyView.ABSTRACT The growing concern over human health issues, driven by increasingly severe electromagnetic pollution from 5G communication, has made the urgent development of high‐performance electromagnetic wave (EMW) absorbing materials. Although carbide‐based materials are promising because of their conductive and polarization losses, existing single ...
Chenqiang Duan +9 more
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2015 深圳湾体育中心钢结构屋盖为超大跨度空间结构,由单层网壳、双层曲面网架及竖向支撑系统构成。单层网壳为复杂的空间曲面网格结构,采用箱形弯扭构件编织而成的四边形网格构成。首先基于弹性屈曲分析方法,深入地研究了结构的失稳模态和成因;其次,通过全过程跟踪结构的平衡路径,对结构非线性弹性和弹塑性稳定性能进行了研究,揭示了该类网壳结构的特殊失稳机理,提出针对该工程网壳结构的稳定设计准则;最后,采用有限元对网壳的局部稳定进行了分析,基于分析结果给出了网壳构件的计算长度系数取值。
郭宇飞, 陈彬磊, 甘明
doaj
Ion Irradiation Effects and Evaluation of Al/B4C Neutron Absorbing Materials and Zirconium Alloys [PDF]
, 2015 中子吸收材料和核燃料包壳材料与核燃料安全密切相关。中子吸收材料用于乏燃料的运输和储存中，保持燃料的次临界状态，防止临界事故发生；核燃料包壳材料是防止核燃料和高放射性物质泄漏的重要屏障。本论文主要研究了Al/B4C中子吸收材料和锆合金包壳材料的离子辐照效应，并进行了服役评估。 Al/B4C金属基复合材料具有良好的机械性能，热传导性能和中子吸收性能，主要应用于乏燃料的干式储存罐和乏燃料池格架中。在服役过程中，Al/B4C中子吸收材料不可避免地经受着中子辐照和氦的累积。为了研究辐照效应以及氦在材料中的行为 ...
张飞飞
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Design and stability analysis on three-DOF double parallel hydraulic support [PDF]
, 2016 Since the column and the top beam of the present four-bar hydraulic support fail to bear the lateral force,the lateral force is transferred to the rod via the shield beam,which often leads to the falling down of the support or damage of the support ...
HU Song +4 more
core +1 more source
Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract The nested subset pattern (nestedness) has been widely used to explain species distributions in island and fragmented systems. Mountain sky islands serve as critical natural laboratories for understanding the evolutionary consequences of geographic isolation and climate
Caiwen Zhang +5 more
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2018 铝合金板式节点网壳是一种典型的半刚性节点网壳。采用ANSYS有限元软件对铝合金板式节点网壳弹塑性稳定性能进行了有限元分析。建立了考虑节点刚度的杆件单元模型。采用Combin39单元对节点非线性弯曲刚度进行模拟。分析了节点刚度对网壳失稳模态、应力分布和极限承载力的影响。研究发现,节点的非线性弯曲刚度对网壳整体稳定性能具有削弱作用,其削弱作用随着网壳矢跨比的减小而加大。最后,为了了解节点刚度四折线模型中各参数对网壳稳定性能的影响而进行了参数分析。研究表明,网壳极限承载力随着滑移弯矩和嵌固刚度的减小而降低 ...
熊哲 +4 more
doaj
, 2019 为研究干湿循环对花岗岩残积土抗剪强度特性和抗剪强度参数的影响,分析花岗岩残积土边坡的稳定性,改进了常规的单元试验方法.以整个花岗岩残积土边坡为试验对象进行干湿循环模拟,在每次循环后直接在边坡坡面上切取花岗岩残积土试样进行直剪试验.在此基础上,利用有限元软件ABAQUS对一实际边坡进行了干湿循环的数值模拟,在每次循环模拟前对上一次模拟结果进行分析,将等效塑性应变较大区域的土体强度进行适当折减,分析每次循环后花岗岩残积土边坡的应力应变、稳定性以及塑性变形.试验结果表明:花岗岩残积土的抗剪强度随干湿循环次数 ...
于佳静, 张波, 王晖, 陈东霞
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Seepage characteristics of accumulation landslides under different types of heavy rainfall stability analysis [PDF]
Heavy rainfall is a major causes of sedimentary landslide disasters, and understanding the spatiotemporal dynamic characteristics of the seepage field in landslides under heavy rain is crucial for evaluating landslide stability and providing ...
Hao SHI +5 more
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Hobbyist preferences for pet freshwater turtles
Conservation Biology, EarlyView.Abstract The burgeoning pet trade is a primary threat to wild freshwater turtles worldwide. Although the risks from commercial exploitation of turtles have been discussed widely, there is little empirical research on preferences for pet turtles from a hobbyists’ perspective.
Jingjing Zhao +7 more
wiley +1 more source