1 武汉理工大学，硅酸盐建筑材料国家重点实验室，武汉 430070
2 济南大学，山东省建筑材料制备与测试技术重点实验室，济南 250022
石灰石煅烧黏土水泥(LC3)是一备受关注的新型、低碳胶凝材料体系，通过将煅烧黏土、石灰石粉与石膏复合并替代部分水泥熟料有效提高了胶凝材料的经济和生态效益。本工作分别从LC3体系水化、微观结构及性能、原材料生产及替代、应用前景及碳排放几个方面总结了该领域最新研究进展，并针对制约LC3体系在中国应用及发展的关键问题，如黏土质原材料地区性差异、去杂/煅烧工艺、可替代硅铝质原材料可用性等以及该领域研究中存在的不足，如水化热动力学模型的完善、LC3基水泥混凝土材料/结构长期性能研究等进行了讨论和展望。
石灰石煅烧黏土水泥 水化机理 碳排放 limestone calcined clay cement hydration mechanism carbon emission
1 济南大学 山东省建筑材料制备与测试技术重点实验室, 济南 250022
2 济南大学材料科学与工程学院, 济南 250022
铁相作为低碳高抗蚀水泥熟料的关键矿物, 对改善水泥生料易烧性、熟料的形成与水化及提升水泥抗离子侵蚀能力发挥重要作用。本文综述了铁相的物化特性并总结了其对硅酸盐水泥与硫铝酸盐水泥影响的最新研究进展, 重点就铁相对两种水泥熟料矿物形成、水化速率与产物、力学与抗离子侵蚀性能影响进行了分析与讨论, 并在最后提出了低碳高抗蚀水泥亟待解决的问题与应用前景。
铁相 水泥熟料 矿物形成 水化 抗侵蚀性能 ferrite phase cement clinker mineral formation hydration corrosion resistance
1 合肥市气象局, 安徽 合肥 230041
2 安徽省人工影响天气办公室, 安徽 合肥 230031
3 中国气象局气象探测中心, 北京 100081
为解决大部分设备无法单独获取全天空云底高度的问题，基于中国气象局大气探测基地可见光/红外天空成像仪和毫米波云雷达2019年6月的灰度值与云底高度数据，利用辐射传输模式计算地面8～14 μm波段向下红外辐射随天顶角的变化关系，并根据红外波段测得的天顶云底灰度值与非天顶位置的天顶角余弦灰度值之间的线性关系，从而反演得到全天空云底高度。结果表明：(1) 相比于全天无云的情形，在一天的相同时间时，全天有云时的天顶灰度值较高。(2) 当云底高度为2000 m以上且云层较厚时，云底高与红外模块所测灰度值的相关性明显好于云层较薄的低云。(3) 2019年8月12日的个例验证结果显示，反演云高与通过云雷达测得的实际云高相关系数为0.956，而与取天顶附近约30°天顶角得到的云高相关系数为0.9508。
全天空成像仪 云雷达 灰度值 云底高 all-sky imager cloud radar grey value cloud base height 
Author Affiliations
Abstract
1 Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
2 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China
The phase summation effect in sum-frequency mixing process is utilized to avoid a nonlinearity obstacle in the power scaling of single-frequency visible or ultraviolet lasers. Two single-frequency fundamental lasers are spectrally broadened by phase modulation to suppress stimulated Brillouin scattering in fiber amplifier and achieve higher power. After sum-frequency mixing in a nonlinear optical crystal, the upconverted laser returns to single frequency due to phase summation, when the phase modulations on two fundamental lasers have a similar amplitude but opposite sign. The method was experimentally proved in a Raman fiber amplifier-based laser system, which generated a power-scalable sideband-free single-frequency 590 nm laser. The proposal manifests the importance of phase operation in wave-mixing processes for precision laser technology.
high power phase summation single-frequency laser stimulated Brillouin scattering sum-frequency generation High Power Laser Science and Engineering
2023, 11(2): 02000e18
1 济南大学山东省建筑材料制备与测试技术重点实验室, 济南 250022
2 咸阳陶瓷研究设计院有限公司, 咸阳 712000
为实现“双碳”目标, 推动大宗固废的资源化利用, 开发探究多种固废协同制备发泡陶瓷材料的方法理论, 以花岗岩锯泥和大理石废石粉为主要原料, SiC为发泡剂, 通过高温烧结制备高闭气孔率的发泡陶瓷, 研究原材料配比、烧结温度以及发泡剂掺量对发泡陶瓷的孔结构及性能的影响。结果表明, 大理石废石粉中的CaCO3在高温下分解出的CaO是有效的助熔剂, 能够破坏Si—O键, 降低液相的黏度, 促进发泡。同时CaO能够与SiO2反应生成硅灰石, 提高材料的机械强度。在烧结温度为1 130 ℃、大理石废石粉质量掺量为10%、SiC质量掺量为1.0%时, 制备的发泡陶瓷孔结构均匀, 综合性能最佳, 闭口气孔率为79.16%, 体积密度为583.42 kg/m3, 抗压强度为3.86 MPa, 吸水率为0.40%。本研究为花岗岩锯泥和大理石废石粉回收利用制备发泡陶瓷提供了理论基础。
发泡陶瓷 花岗岩锯泥 大理石废石粉 碳化硅 高温烧结 固废利用 foamed ceramics granite scrap marble scrap silicon carbide high-temperature sintering solid waste utilization
Author Affiliations
Abstract
High Power Laser Science and Engineering
2023, 11(2): 02000e16
Author Affiliations
Abstract
1 Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
2 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, and Shanghai Key Laboratory of Solid-State Laser and Application, Shanghai, China
High-power continuous-wave single-frequency Er-doped fiber amplifiers at 1560 nm by in-band and core pumping of a 1480 nm Raman fiber laser are investigated in detail. Both co- and counter-pumping configurations are studied experimentally. Up to 59.1 W output and 90% efficiency were obtained in the fundamental mode and linear polarization in the co-pumped case, while less power and efficiency were achieved in the counter-pumped setup for additional loss. The amplifier performs indistinguishably in terms of laser linewidth and relative intensity noise in the frequency range up to 10 MHz for both configurations. However, the spectral pedestal is raised in co-pumping, caused by cross-phase modulation between the pump and signal laser, which is observed and analyzed for the first time. Nevertheless, the spectral pedestal is 34.9 dB below the peak, which has a negligible effect for most applications.
in-band pump Raman fiber laser single-frequency Er fiber amplifier High Power Laser Science and Engineering
2023, 11(1): 010000e3
随着物联网技术(IoT)的发展,越来越多的IoT传感器被应用于环境检测、物流管理、生产制造和医疗保健等领域。IoT传感器的使用年限取决于内部电池的使用时间,而内部电池是不可拆卸的,因此一旦电池损坏或者电量耗尽,则需要更换新IoT传感器,这大大提高了成本。能量收集技术的发展为解决该难题提供了新方向,该技术将环境中的微弱能量收集起来,通过相关技术转换成电能,为IoT传感器供电,摆脱了其对电池的依赖。文章综述了能量收集系统的关键技术,比较了不同电路结构的优缺点,并且总结了最大功率追踪技术(MPPT),表明MPPT技术从一维MPPT技术发展到三维MPPT技术,现在已有更多的辅助技术来提高MPPT电路的跟踪精度。为了实现更广泛的应用,多输入多输出的转换器已然成为研究重点,文章综述了多能量源输入多输出电压的转换器结构,静态功耗和动态范围等性能指标成为关注的重点。
能量收集 DC-DC转换器 太阳能 热能 energy harvesting DC-DC converter solar energy thermal energy
Author Affiliations
Abstract
1 Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, 336 Nanxinzhuang West Road, Jinan, Shandong 250022, P. R. China
2 Underwater Acoustic Transducer Lab, Shanghai Marine Electronic Equipment Research Institute, Shanghai 201108, P. R. China
To improve the acoustic radiation performance of the spherical transducer, a prestressed layer is formed in the transducer through fiber winding. The influence of the prestressed layer on the transducer is studied from the effects of the radial prestress () and acoustic impedance, respectively. First, a theoretical estimation of is established with a thin shell approximation of the prestressed layer. Then, the acoustic impedance is measured to evaluate the efficiency of sound energy transmission within the prestressed layer. Further, the ideal effects of on the sound radiation performances of the transducer are analyzed through finite element analysis (FEA). Finally, four spherical transducers are fabricated and tested to investigate their dependence of actual properties on the prestressed layer. The results show that with the growth of , the acoustic impedance of the prestressed layer grows, mitigating the enormous impedance mismatch between the piezoelectric ceramic and water, while increasing attenuation of the acoustic energy, resulting in a peak value of the maximum transmitting voltage response () at 1.18 MPa. The maximum drive voltage increases with , leading to a steady growth of the maximum transmitting sound level (), with a noticeable ascend of 3.9 dB at a 3.44 MPa . This is a strong credibility that the prestressed layer could improve the sound radiation performance of the spherical transducer.To improve the acoustic radiation performance of the spherical transducer, a prestressed layer is formed in the transducer through fiber winding. The influence of the prestressed layer on the transducer is studied from the effects of the radial prestress () and acoustic impedance, respectively. First, a theoretical estimation of is established with a thin shell approximation of the prestressed layer. Then, the acoustic impedance is measured to evaluate the efficiency of sound energy transmission within the prestressed layer. Further, the ideal effects of on the sound radiation performances of the transducer are analyzed through finite element analysis (FEA). Finally, four spherical transducers are fabricated and tested to investigate their dependence of actual properties on the prestressed layer. The results show that with the growth of , the acoustic impedance of the prestressed layer grows, mitigating the enormous impedance mismatch between the piezoelectric ceramic and water, while increasing attenuation of the acoustic energy, resulting in a peak value of the maximum transmitting voltage response () at 1.18 MPa. The maximum drive voltage increases with , leading to a steady growth of the maximum transmitting sound level (), with a noticeable ascend of 3.9 dB at a 3.44 MPa . This is a strong credibility that the prestressed layer could improve the sound radiation performance of the spherical transducer.
Radial prestress acoustic impedance spherical transducers transmission voltage response transmission sound level Journal of Advanced Dielectrics
2022, 12(6): 2241004
