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991.
为有效提高Mg(OH)_2纳米粒子在硅丙乳液中的相容性与分散稳定性,在油酸修饰Mg(OH)_2纳米粒子的基础上,以甲基丙烯酸甲酯、丙烯酸丁酯、丙烯酸与乙烯基三乙氧基硅烷为共聚单体,通过乳液聚合法制备出具有核壳结构的硅丙乳液包覆Mg(OH)_2复合材料。利用傅里叶变换红外光谱仪(FTIR)、X射线衍射仪(XRD)、透射电子显微镜(TEM)等测试手段对样品结构、形貌进行了表征。通过燃烧实验,研究了硅丙乳液包覆Mg(OH)_2纳米粒子对水性防火涂料阻燃性能的影响。结果表明,油酸通过酯化作用修饰在Mg(OH)_2纳米粒子表面,借助油酸分子中双键结构,丙烯酸类混合单体在纳米Mg(OH)_2表面完成聚合过程,形成以Mg(OH)_2纳米粒子为核、硅丙乳液为壳的复合材料。XRD与热分析表明经硅丙乳液包覆的纳米Mg(OH)_2晶体结构与热稳定性能未受影响。此外,掺杂0.1%(质量分数)的硅丙乳液包覆Mg(OH)_2可使水性防火涂料阻燃时间延长至113 min,较未掺杂水性涂料阻燃时间(91min)提高约23%。 相似文献
992.
基于Pellenq等的建模思路,构造了不同钙硅比(C/S)的水化硅酸钙(C-S-H)原子模型,采用分子动力学方法模拟了C-S-H在轴向拉伸载荷作用下的力学性能。重点比较分析了不同钙硅比的C-S-H在无水及含水情况下的拉伸应力-应变曲线。模拟结果表明:(1)与钙硅比为1.0的情况相比,钙硅比大于1.0时C-S-H结构的抗拉强度显著下降;(2)钙硅比大于1.0时,钙氧间的相互作用在承受载荷方面起重要作用,有效弥补了结构中因SiO_2基团缺失引起的缺陷,使得C-S-H的强度下降程度趋缓;(3)当应变达到一定程度时,水分子能够切断钙氧间的相互作用,使得C-S-H结构的强度进一步降低甚至引起断裂失效。 相似文献
993.
在湿球磨条件下以600 r/min高能球磨混粉,并将球磨后的粉末经过热压烧结-热挤压成型制备(Mg2B2O5w+ND)/ZK60镁基复合材料。研究了(Mg2B2O5w+ND)/ZK60镁基复合材料在不同载荷和转速下的干摩擦磨损性能。结果表明:干摩擦条件下,材料的摩擦系数随着滑动距离的增加会经历跑和阶段和稳定阶段;材料的质量磨损率随着转速的增大而降低,随着载荷的增大而增大,且基体镁合金的质量磨损率始终低于复合材料。随着摩擦载荷和转速的增加,材料的摩擦系数减小,然后逐渐趋于平稳。混杂增强的镁基复合材料相比基体合金具有更低的摩擦系数。 相似文献
994.
995.
Duyao Zhang Shoujin Sun Dong Qiu Mark A. Gibson Matthew S. Dargusch Milan Brandt Ma Qian Mark Easton 《Advanced Engineering Materials》2018,20(5)
996.
Multi‐principal elemental alloys, commonly referred to as high‐entropy alloys (HEAs), are a new class of emerging advanced materials with novel alloy design concept. Unlike the design of conventional alloys, which is based on one or at most two principal elements, the design of HEA is based on multi‐principal elements in equal or near‐equal atomic ratio. The advent of HEA has revived the alloy design perception and paved the way to produce an ample number of compositions with different combinations of promising properties for a variety of structural applications. Among the properties possessed by HEAs, sluggish diffusion and strength retention at elevated temperature have caught wide attention. The need to develop new materials for high‐temperature applications with superior high‐temperature properties over superalloys has been one of the prime concerns of the high‐temperature materials research community. The current article shows that HEAs have the potential to replace Ni‐base superalloys as the next generation high‐temperature materials. This review focuses on the phase stability, microstructural stability, and high‐temperature mechanical properties of HEAs. This article will be highly beneficial for materials engineering and science community whose interest is in the development and understanding of HEAs for high‐temperature applications. 相似文献
997.
Tensile Strength Evolution and Damage Mechanisms of Al–Si Piston Alloy at Different Temperatures 下载免费PDF全文
Meng Wang Jianchao Pang Yu Qiu Haiquan Liu Shouxin Li Zhefeng Zhang 《Advanced Engineering Materials》2018,20(2)
998.
Microstructure,Phase Composition,and Thermal Stability of Two Zirconium Alloys Subjected to High‐Pressure Torsion at Different Temperatures 下载免费PDF全文
Stanislav. O. Rogachev Sergey A. Nikulin Andrey B. Rozhnov Mikhail V. Gorshenkov 《Advanced Engineering Materials》2018,20(9)
999.
Factors associated with serum magnesium and vascular stiffness in maintenance hemodialysis patients 下载免费PDF全文
Mai Yorifuji Takahiro Kuragano Sayuri Kawada Wataru Fukao Kazuhiro Toyoda Takeshi Nakanishi 《Hemodialysis international. International Symposium on Home Hemodialysis》2018,22(3):342-350
Introduction : We evaluated the associated factors of serum magnesium in patients on maintenance hemodialysis (MHD). Furthermore, we evaluated the relationship between low serum magnesium and arteriosclerosis in these patients. Methods : In 129 patients on MHD, we evaluated the blood levels of magnesium, brachial‐ankle pulse wave velocity (ba‐PWV), ankle‐brachial index (ABI), and intima‐media thickness of the common carotid artery (IMT). Findings : In MHD patients, the serum level of magnesium was significantly correlated with age, calcium, TNF‐α, albumin, and ba‐PWV but not with ABI or IMT. In the multiple regression analysis, albumin (P = 0.0001, β = 0.31) and calcium (P = 0.029, β = 0.18) were selected as significant predictors of the magnesium level in MHD patients. Furthermore, the serum level of magnesium, as well as systolic blood pressure (P = 0.0001, β = 0.32) and age (P = 0.005, β = 0.25), were selected as significant (P = 0.012, β = ?0.22) predictors of ba‐PWV in MHD patients. Discussion : In MHD patients, the serum magnesium level was associated with the serum levels of calcium and albumin. Furthermore, a low serum magnesium level in MHD patients was associated with the index of vascular stiffness. 相似文献
1000.
Yu-Kyoung Kim Seo-Young Kim Ken Bode Yong-Seok Jang Tae-Young Kwon 《Science and Technology of Advanced Materials》2018,19(1):324-335
Magnesium alloys are biodegradable metals receiving increasing attention, but the clinical applications of these materials are delayed by concerns over the rapid corrosion rate and gas formation. Unlike corrosion, which weakens mechanical properties, the gas formation issue has received little attention. Therefore, we evaluated the gas formation and biological effects for Mg implants through preclinical (immersed in Earle’s balanced salt solution and in vivo) and clinical studies. The immersion test examined the gas volume and composition. The in vivo study also examined gas volume and histological analysis. The clinical study examined the gas volume and safety after Mg screw metatarsal fixation. Gas was mainly composed of H2, CO and CO2. Maximum volumes of gas formed after 5 days for in vivo and 7 days in clinical study. Within the clinical examination, two superficial wound complications healed with local wound care. Osteolytic lesions in the surrounding metaphysis of the Mg screw insertion developed in all cases and union occurred at 3 months. Mg implants released gas with variable volumes and composition (H2, CO, and CO2), with no long-term toxic effects on the surrounding tissue. The implants enabled bone healing, although complications of wound breakdown and osteolytic lesions developed. 相似文献