为考察白云石对水泥基材料抗硫酸盐侵蚀性能的影响,本文采用10%、20%、30%(质量分数,下同)白云石掺入水泥净浆与水泥砂浆试件中,在低温条件下浸泡于5%硫酸镁和5%硫酸钠溶液中,并进行硫酸盐侵蚀试验。定期观察试件的宏观形貌变化,并定量分析其侵蚀产物。测定水泥砂浆试件抗折强度与抗压强度并进行宏观分析,以此得出不同种类硫酸盐对试件生成碳硫硅钙石的影响。采用热力学模拟探究白云石对水泥胶凝体系产物的影响。结果表明:当白云石掺量为10%~20%时,能抑制水泥基材料中碳硫硅钙石的生成,水泥基材料的抗硫酸盐侵蚀性能有较大提高,水泥砂浆试件抗折强度有明显改善,这与热力学模拟结果基本一致。
白云石 水泥基材料 硫酸盐 热力学分析 定量分析 碳硫硅钙石 dolomite cement-based material sulfate thermodynamic analysis quantitative analysis thaumasite
Yuhang Li 1,2,3Tianyi Gan 1,3Bijie Bai 1,2,3Çağatay Işıl 1,2,3[ ... ]Aydogan Ozcan 1,2,3,*
Author Affiliations
Abstract
1 University of California, Department of Electrical and Computer Engineering, Los Angeles, California, United States
2 University of California, Department of Bioengineering, Los Angeles, California, United States
3 University of California, California NanoSystems Institute, Los Angeles, California, United States
Free-space optical information transfer through diffusive media is critical in many applications, such as biomedical devices and optical communication, but remains challenging due to random, unknown perturbations in the optical path. We demonstrate an optical diffractive decoder with electronic encoding to accurately transfer the optical information of interest, corresponding to, e.g., any arbitrary input object or message, through unknown random phase diffusers along the optical path. This hybrid electronic-optical model, trained using supervised learning, comprises a convolutional neural network-based electronic encoder and successive passive diffractive layers that are jointly optimized. After their joint training using deep learning, our hybrid model can transfer optical information through unknown phase diffusers, demonstrating generalization to new random diffusers never seen before. The resulting electronic-encoder and optical-decoder model was experimentally validated using a 3D-printed diffractive network that axially spans <70λ, where λ = 0.75 mm is the illumination wavelength in the terahertz spectrum, carrying the desired optical information through random unknown diffusers. The presented framework can be physically scaled to operate at different parts of the electromagnetic spectrum, without retraining its components, and would offer low-power and compact solutions for optical information transfer in free space through unknown random diffusive media.
optical information transfer electronic encoding optical decoder diffractive neural network diffusers Advanced Photonics
2023, 5(4): 046009
强激光与粒子束
2023, 35(6): 064001
1 大亚湾核电运营管理有限责任公司, 广东 深圳 518124
2 苏州热工研究院有限公司, 江苏 苏州 215004
采用激光同轴送粉技术制备Stellite6钴基熔覆层, 通过正交试验、单层单道、单层多道和多层多道工艺试验优化激光熔覆工艺参数。利用扫描电子显微镜、光学显微镜、X射线衍射仪表征了熔覆层显微组织结构, 同时分析了微观硬度和耐摩擦磨损性能。结果表明, 以熔覆层稀释率、成形系数和显微硬度为优化目标参数, 可有效筛选激光熔覆Stellite6涂层制备工艺。所制备Stellite6涂层组织均匀, 熔合线附近为平面晶, 涂层中部区域为树枝晶, 顶部区域为等轴晶。熔覆层物相由fcc-Co、(Co,W)3C与Cr23C6等组成, 平均硬度为457 HV。熔覆层耐摩擦磨损性能优于316L不锈钢基体, 其主要磨损机制为磨粒磨损。
激光熔覆 Stellite6涂层 微观组织 工艺优化 硬度 摩擦磨损 laser cladding Stellite6 alloy coating microstructure parameter optimization microhardness friction and wear
1 新疆大学建筑工程学院, 乌鲁木齐 830047
2 喀什大学土木工程学院, 喀什 844006
3 同济大学材料科学与工程学院, 上海 201800
为考察受载锂渣混凝土抗氯离子渗透性能, 本文设计了锂渣取代水泥质量0%、10%、20%和30%的C20、C30和C40混凝土, 对混凝土试件施加极限压荷载的10%、30%和50%, 作为持续压应力, 进行氯离子渗透性能试验。结果表明: 水灰比范围在0.40~0.62时, 电通量随着水灰比的增大而增大; 对于施加不同压应力的混凝土, 当压应力比达到0.3时, C20和C30混凝土电通量有明显的提升, 当压应力比达到0.5时, C40混凝土电通量有明显的提升; 对于不同锂渣取代量的混凝土, 电通量随着锂渣取代量的增大而减小。结合 Fick第二定律和质量守恒定律, 建立在持续荷载作用下锂渣混凝土氯离子渗透模型, 结果表明, 氯离子在浸泡环境下的渗透性能符合试验规律, 模拟结果与试验结果一致。
混凝土 荷载 锂渣 氯离子 渗透性 数值模拟 concrete load lithium slag chloride ion permeability numerical simulation
光子学报
2021, 50(11): 1123002
1 中国科学院 近代物理研究所,兰州 730000;中国科学院大学 核科学与技术学院,北京 100049;惠州离子科学研究中心,广东 惠州 516003
2 中国科学院 近代物理研究所,兰州 730000;惠州离子科学研究中心,广东 惠州 516003
3 中国科学院 近代物理研究所,兰州 730000
4 中国科学院 近代物理研究所,兰州 730000;中国科学院大学 核科学与技术学院,北京 100049
5 中国科学院大学 核科学与技术学院,北京 100049
强流重离子加速器装置(HIAF)的增强器(BRing)二极铁电源样机采用多模块串并联的全储能快循环脉冲电源实现方案,电源功率达到MW级。由于电源规模庞大和功率巨大,为了在运行中迅速保护电源设备,设计并实现了一套双冗余的基于可编程逻辑控制器(PLC)、模块故障联锁板和现场可编程门阵列(FPGA)的模块故障联锁保护系统,利用硬件和软件同时对电源功率单元模块实施故障检测、故障传递和故障保护。设计完成后分别从电源联锁环路的响应时间、核心控制板故障引发电源环路联锁的总时间和设备故障响应等三个方面进行测试,测试结果表明,在电源发生故障时,模块故障联锁保护系统满足电源样机对实时性和可靠性的要求,达到设计目标。
模块故障联锁 数字控制器 故障检测 故障保护 module fault interlock digital controller fault detection fault protection HIAF-BRing HIAF-BRing 强激光与粒子束
2021, 33(7): 074002
清华大学精密仪器系激光与光子技术研究室, 光子测控技术教育部重点实验室, 北京 100084
被动锁模光纤激光器是超快激光家族中的重要成员,凭借光纤的优良特性,如鲁棒性好、结构简单紧凑、稳定可靠等,吸引了相关研究者的广泛关注。近年来,随着光纤制备工艺和锁模技术的不断进步,光纤锁模激光器得到了迅速发展。基于此,描述锁模技术及不同色散区的锁模激光器,并依据锁模机制、脉冲性质等分类叙述,综述了国内外该领域的研究现状和发展趋势,重点阐述全光纤非线性环形放大镜和微纳光纤锁模激光器的研究进展。
激光技术 光纤锁模激光器 非线性环形放大镜 微纳光纤 耗散孤子 脉动孤子 中国激光
2021, 48(15): 1501006
Author Affiliations
Abstract
1 School of Science, Jiangsu Provincial Research Center of Light Industrial Optoelectronic Engineering and Technology, Jiangnan University, Wuxi 214122, China
2 School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu 215556, China
3 The 38th Research Institute of China Electronics Technology Group Corporation, Hefei 230000, China
We have fabricated the AlGaN solar-blind ultraviolet metal–semiconductor–metal (MSM) photodetectors (PDs) with an Al composition of 0.55. The surface roughness and dislocations of the high-Al-content epitaxial layer are analyzed by atomic force microscopy and transmission electron microscopy, respectively. The device exhibits high spectral responsivity and external quantum efficiency due to the photoconductive gain effect. The current reveals a strong dependence on high temperatures in the range of 4–10 V. Moreover, the Poole–Frenkel emission model and changing space charge regions are employed to explain the carrier transport and photoconductive gain mechanisms for the AlGaN PD, respectively.
metal–semiconductor–metal solar blindness photodetector Poole–Frenkel emission photoconductive gain Chinese Optics Letters
2021, 19(8): 082504