为改善超细水泥灌浆料的性能，将多壁碳纳米管(MWCNTs)加入超细水泥灌浆料中，测试了其对灌浆料强度、可灌性相关参数，以及灌入混凝土缝隙后黏结效果的影响。结果表明：直径为10~20 nm的MWCNTs在超细水泥灌浆料中的最佳掺量为0.10%(质量分数)，此时灌浆料56 d抗折强度、抗压强度、折压比相对于未掺加时分别提高了24.3%、23.4%、7.1%；随MWCNTs掺量增加，灌浆料的流动度降低，黏度增加，需要的灌浆压力增加，即灌浆料的可灌性逐渐降低，但在掺量不高于0.10%(质量分数)时，灌浆料硬化后灌浆区域孔隙率随MWCNTs掺量提高未明显增加，灌浆效果没有明显降低；劈裂抗拉试验结果显示，掺加MWCNTs可使灌浆料与混凝土的黏结性能明显增强。
多壁碳纳米管 超细水泥灌浆料 强度 灌浆压力 可灌性 黏结性能 multi-walled carbon nanotubes (MWCNTs) ultra-fine cement grout strength grouting pressure grouting property bond performance
1 陕西高速机械化工程有限公司, 西安 710038
2 长安大学建筑工程学院, 西安 710064
为研究混磨不同细度石灰石粉-粉煤灰对水泥基胶凝材料水化进程和早期力学性能的影响规律, 本文采用等温量热法测定了不同细度复合胶凝体系在水化温度为20 ℃时的水化放热速率和放热量, 根据Krstulovic-Dabic提出的水化动力学模型计算了复合胶凝体系水化反应各阶段的动力学参数。结果表明: 增加石灰石粉和粉煤灰的细度可促进复合胶凝体系水化产物的结晶成核与晶体生长, 缩短水化诱导期结束时间和达到最大放热速率时间, 加速水泥的水化反应速率。石灰石粉和粉煤灰细化会缩短相边界反应过程时间, 使复合胶凝体系在水化程度更高时发生反应控制机制转变。抗压强度试验表明增加细度可明显提高胶砂试件的早期强度, 其后期强度保持稳定。
石灰石粉-粉煤灰 细度 胶凝材料 水化反应速率 水化动力学模型 力学性能 limestone powder-fly ash fineness cementitious material hydration reaction rate hydration kinetic model mechanical property
光子学报
2021, 50(12): 1212001
Author Affiliations
Abstract
1 School of Physics, Zhengzhou University, Zhengzhou 450052, China
2 Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
3 Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
In this Letter, we use electromagnetic simulations to systematically investigate the influence of a thin dielectric layer on the local electric field and molecular spectroscopy in the plasmonic junction. It is found that both the intensity and spatial confinement of the electric field and molecular spectroscopy can be significantly enhanced by applying a dielectric layer with large dielectric constant. We also discuss the optimal dielectric layer thickness to obtain the largest quantum efficiency of a dipole emitter. These results may be instructive for further studies in molecular spectroscopy and optoelectronics in plasmonic junctions.
plasmonics decoupling layer scanning tunneling microscope molecular spectroscopy tip-enhanced spectroscopy Chinese Optics Letters
2021, 19(12): 123001
Author Affiliations
Abstract
1 Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
2 Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
In laser-pointing-related applications, when only the centroid of a laser spot is considered, then the position and angular errors of the laser beam are often coupled together. In this study, the decoupling of the position and angular errors is achieved from one single spot image by utilizing a neural network technique. In particular, the successful application of the neural network technique relies on novel experimental procedures, including using an appropriate small-focal-length lens and tilting the detector, to physically enlarge the contrast of different spots. This technique, with the corresponding new system design, may prove to be instructive in the future design of laser-pointing-related systems.
artificial neural networks laser pointing pointing errors High Power Laser Science and Engineering
2020, 8(3): 03000e28
1 中国科学技术大学物理系, 安徽 合肥 230026
2 深圳大学高等研究院, 广东 深圳 518060
石墨烯等离激元在中红外到太赫兹波段有广阔应用前景。以往研究多关注于 石墨烯等离激元和基底声子的耦合,但如何调控这种耦合的报道却很少。一种可能的调控耦合的方式是改变石墨烯 条带周围的介电环境。数值模拟表明,与放置在平整二氧化硅基底上的石墨烯条带相比,放置在凹槽中的石墨烯条带 的等离激元和声子耦合增强。此外,在远离声子频率处色散曲线明显下移,低频段两个色散分支的最大光吸收率也有 显著提高。而将石墨烯条带放置在凸台上则结果相反。研究结果表明石墨烯等离激元和基底声子的耦合可以通过改 变石墨烯条带边缘介电环境这种简单方式得到有效调控。
等离激元 石墨烯 条带 色散 声子 耦合 plasmon graphene ribbon dispersion phonon coupling
1 Xi’an Microelectronics Technology Institute, Xi’an 710119, China
2 State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China
3 Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117581, Singapore
1 Xi'an Microelectronics Technology Institute, Xi'an 710119, China
2 School of Aerospace Engineering, Xiamen University, Xiamen 361005, China
3 Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117576, Singapore
4 Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore
洛阳理工学院 电气工程与自动化系,河南 洛阳 471023
提出了一种新颖的纳米传感器结构,其工作原理是利用双狭缝波导中纳米量级结构变化对狭缝波导内光场能量分布的影响。数值仿真结果表明:该结构的传感器对位移变化的最低响应度可达到1 nm量级,测量量程可达到100 nm左右。有望应用于位移、压力、温度等物理量的高灵敏度测量。
双狭缝波导 纳米传感器 时域有限差分法 有限元法 double slot waveguide nano-sensor FDTD FEM
