Zr-xNb-4Sn alloys with low Young’s modulus and magnetic susceptibility for biomedical implants

The microstructure, mechanical and magnetic properties of Zr–x (8, 9, 10, wt.%)Nb–4Sn alloys were investigated to obtain novel Zr-based alloy with low Young’s modulus and magnetic susceptibility for biomedical implants. After homogenization annealing, hot forging and solution annealing, Zr–8Nb–4Sn, Zr–9Nb–4Sn and Zr–10Nb–4Sn alloys were composed of β+α″ phase, β+α″ phase, β+ω phase, respectively. The temperature at which the α" and ω phase were transformed into β phase during the heating process was about 200 ​°C, and the phase transformation temperature decreased with the increase of Nb element. Among all the Zr–x (x ​= ​8,9,10)Nb–4Sn(wt.%) alloys, Zr–9Nb–4Sn alloy had the lowest Young's modulus of 46.6 ​GPa and the low magnetic susceptibility of 1.294 ​× ​10⁻⁶ cm³g⁻¹, which has a good application prospect for biomedical applications.     

隧道爆破力学模型相似材料配比的正交试验

以砂岩作为模拟对象,研究满足隧道爆破力学模型试验要求的相似材料配比问题.基于正交试验法,选取石英砂、重晶石粉、石膏、水泥和水为相似材料,设置以石英砂/固体、水泥/石膏、重晶石粉/(重晶石粉+石英砂)的质量比为3个因素,每个因素3个水平,共9组配比的正交试验方案.通过室内试验,得到相似材料的密度、单轴抗压强度、弹性模量和声波波速的实测数据.试验结果表明:相似材料的物理力学参数分布范围较广,可满足不同隧道模型试验对相似材料的配比要求.利用极差敏感分析法分析各因素对相似材料参数的敏感性,并通过各因素对相似材料参数影响的直观分析图,分析各因素对相似材料物理力学参数的影响规律.对试验数据进行多元线性回归分析和室内试验,发现最优配合比下的相似材料与原型砂岩的单轴应力-应变曲线具有相似的脆性破坏特征;相似材料物理力学参数的设计值和实测值误差较小.     

大尺寸工程模型试验中的相似材料配比试验研究

大型物理模型试验是研究复杂工程问题的重要方法，如何快速、准确地确定相似材料配比是试验中至关重要的一环.为降低试验成本、简化试验步骤、充分调用原料性能，采用河砂、水泥和石膏这三种最普通的原料，以骨胶比(河砂与水泥石膏的质量比)和水膏比(水泥与石膏的质量比)为变量，进行了45组对比试验，对相似材料的物理及动、静力学参数进行了研究.获得了以河砂、水泥和石膏为原料配制的相似材料各物理量的变化区间；探讨了骨胶比和水膏比对相似材料各物理量的控制作用，并对比了其敏感性；基于多元线性回归分析建立了各因素与物理量间的定量关系，得到的拟合公式能较好地描述相似材料的性质.     

Recent advances and challenges in materials for 3D bioprinting

3D bioprinting has been developed as a promising technology in a wide variety of biomedical applications. However, the successful implementation of bioprinting is still heavily restricted by the relatively narrow range of printable and biocompatible materials. Recently, many comprehensive reviews of the main bioprinting methods, commonly used bioprinting materials and the trending bioprinting applications have been carried out. In this review, we focused on the trends in the development of materials for 3D bioprinting. The significance and recent advances of ECM-based materials, multi-material and stimuli-responsive materials for bioprinting were summarized successively. Moreover, the challenges in current studies and future perspectives of materials for 3D bioprinting were discussed.     

A new microfiltration membrane with three-dimensional reticular architecture for Nano-pollutants removal from wastewater

This research provides a new insight into designing next-generation filtration materials for Nano-pollutants removal from wastewater, and potentially for gas/solid or liquid/solid separation in corrosive environment. Considering the high corrosion and oxidation resistance, Ti–40Al–10Nb–10Cr porous alloy was prepared by powder metallurgy and used as a mechanical support with a pore size of around 10 ?μm. Subsequently, metallic Zn nanoparticles was coated on the Ti–40Al–10Nb–10Cr porous framework by means of chemical vapor deposition, obtaining a novel microfiltration membrane with three-dimensional reticular architecture. Furthermore, the influence of Zn coating on surface morphology, pore feature, and filtration capability of Ti–40Al–10Nb–10Cr porous alloy was investigated. It is of note that the as-prepared microfiltration membrane exhibits an excellent Nano-pollutants filtration efficiency of greater than 99.989% from wastewater. Most importantly, such a three-dimensional reticular architecture provides excellent structural stability, allowing the reutilization of the microfiltration membrane for at least 200 filtration cycles of wastewater treatment.     

自发光材料在隧道安全救援中的应用试验研究

隧道侧壁涂刷反射率较高的材料有利于改善隧道内部照明环境,对隧道安全救援也有积极作用。本文利用自发光材料蓄能释光的功能,分析自发光材料的施工工艺,对7种光源条件下自发光材料的余辉亮度进行模型隧道试验测试,得到自然光照射下初始余辉亮度最大,光源停止照射10 min 后,自发光材料的余辉亮度衰减至初始亮度的10％。同时依托云南保腾高速公路鹿山隧道,现场开展了 LED 灯源条件下的余辉亮度实验,探讨了余辉持续时间与安全救援的关系,发现断电30 min 后墙面的视觉诱导作用仍较明显,能对突发事件中隧道内人员的紧急避险和安全救援起到积极作用,为今后进一步合理利用和开发自发光材料在隧道应急救援中的作用提供参考。     

软磁材料应用研究进展

软磁材料因其饱和磁感应强度高、磁导率高、矫顽力低、损耗低和环境稳定性好等优点,被广泛应用于通信、电源、计算机和各种电子产品等领域。随着信息技术和电子产品数字化的发展,电子仪器设备向着精密化、高效化和节能化方向发展,这就对软磁材料和元件提出了新的要求和挑战。如何取得具有较高饱和磁感应强度和低损耗的软磁材料已成为研究的重点。本文对传统软磁材料与新型软磁材料的研究现状作了总结,并对软磁材料的发展趋势作了展望,为后续软磁材料的发展提供指导方向。     

玻璃粉对混凝土酸侵蚀性能的影响

采用试验方法,研究了玻璃粉替代胶凝材料在不同掺量(0、5%、8%、15%)时对混凝土抗压强度和耐酸侵蚀性的影响。对比了各个试样在5%H2SO4溶液和5%CH3COOH溶液中腐蚀28 d后的质量亏损和抗压强度损失,并采用SEM分析了试样腐蚀后的表面形貌。结果表明,玻璃粉有利于提高混凝土的耐H2SO4和CH3COOH侵蚀性,耐CH3COOH侵蚀差于耐H2SO4腐蚀,H2SO4侵蚀后的试样表面形成了大量石膏,CH3COOH侵蚀后试样表面疏松并出现了大量孔洞和裂纹。当玻璃粉掺量为8%时,试样的耐H2SO4和CH3COOH侵蚀性最佳。     

低温调节阀阀座软密封特性研究(Ⅰ):常温密封性能

分别采用高分子聚合物PTFE、PCTFE和PEEK作为低温调节阀阀座软密封的密封材料,在常温(300 K)情况下,对比研究了采用不同密封材料的低温阀阀座的漏率与密封比压的关系. 在此基础上,测试了不同进口压力下阀座的密封漏率,以及密封性能对压力的稳定性. 试验分析结果表明,采用PCTFE密封材料的低温阀阀座不仅具有优异的密封性能,而且在不同的工作压力条件下,漏率与压力呈线性变化,具有较高的压力稳定性.      

基于有限积分法的电磁兼容吸波材料反射率的建模仿真

针对电磁兼容吸波材料反射率试验测试成本较高、理论方法难以精确预测的问题,提出了基于有限积分法的吸波材料反射率的建模仿真方法.使用该方法计算了矩形同轴测试装置空载反射系数,以及分别加载铁氧体瓦和角锥泡沫吸波材料后的反射系数.吸波材料的介电常数和磁导率使用二阶通用色散模型进行拟合.对于铁氧体瓦,仿真得到的反射率略优于实测值,与产品提供的反射率曲线相比,在谐振点处相差10 d B.对于角锥泡沫吸波材料,仿真结果与实测值在有效测试频率范围内相差7 d B.对仿真结果与实验结果的差别进行分析,证明了该方法的可行性.