Highly ordered graphene architectures by duplicating melamine sponges as a three-dimensional deformation-tolerant electrode

In this study, macroscopic graphene-wrapped melamine foams (MF-G) were fabricated by an MF-templated layer-by-layer (LBL) assembly using graphene oxide as building blocks, followed by solution-processed reduction. By concisely duplicating sponge-like, highly ordered three-dimensional architectures from MF, the resulting MF-G with an interconnected graphene-based scaffold and tunable nanostructure was explored as compressible, robust electrodes for efficient energy storage. A thin layer of pseudocapacitive polypyrrole (PPy) was then attached and uniformly coated on MF-G, resulting in a well-defined core–double-shell configuration of the MF-G-PPy ternary composite sponges. The as-assembled devices exhibited enhancement of supercapacitor performance, with a high specific capacitance of 427 F·g^?1 under a compressive strain of 75% and an excellent cycling stability with only 18% degradation after 5,000 charge–discharge cycles. Besides, the MF-G-PPy electrode maintained stable capacitance up to 100 compression–release cycles, with a compressive strain of 75%. These encouraging results thus provide a new route towards the low-cost, easily scalable fabrication of lightweight and deformation-tolerant electrodes.

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大型深基坑支撑爆破拆除中的技术措施

分析了深基坑支撑拆除工程爆破中的技术难点,提出了对重点对象的保护措施,研究了支撑爆破振动的有效控制和延期网路的可靠连接,对装药量、爆破防护和施工组织进行了讨论,工程实践证明采用介绍的设计方案可以得到良好的爆破效果.     

两种典型结构强流自箍缩二极管技术研究

主要介绍了箍缩聚焦二极管和自箍缩离子束二极管的研究进展。重点介绍了近几年发展的阳极杆箍缩聚焦二极管的理论模拟和实验结果,在“闪光二号”加速器和2MV脉冲功率驱动源上进行了阳极杆箍缩二极管实验,二极管输出电压1．8—2．1MV,电流40—60kA,脉宽（FWHM）50～60n8,1m处的脉冲X剂量约20～30mGy,焦斑直径约Imm,X射线最高能量1．8MeV。在“闪光二号”加速器上开展了高功率离子束的产生和应用研究,给出了自箍缩反射离子束二极管的结构和工作原理,实验获得的离子束峰值电流～160kA,离子的峰值能量-500keV,开展了利用高功率质子束轰击19F靶产生6～7MeV准单能脉冲γ射线,模拟x射线热一力学效应等应用基础研究。     

Dry etching of GaN using chemically assisted Ion beam etching with HCI and H2/Cl2

The dry etching characteristics of GaN were investigated using chemically assisted ion beam etching (CAIBE) with HCI and H₂/Cl₂ gas. Etch rates using CAIBE/HC1 were investigated as a function of Ar ion beam energy and substrate temperature. These results were compared to CAIBE/C1₂. Etch rates were also investigated for CAIBE/H₂/Cl₂ for various ratios of H₂:C1₂. Highly anisotropic submicron lines are demonstrated using CAIBE/HC1. Auger electron spectroscopy was used to investigate surface stoichiometric changes of samples etched with CAIBE/HC1, CAIBE/H₂/Cl₂,, and CAIBE/C1₂. The diffusion of deuterium into GaN during etching was also investigated using secondary ion mass spectrometry.     

Damage detection in beam-like structures using static shear energy redistribution

In this study, a static shear energy algorithm is presented for the damage assessment of beam-like structures. According to the energy release principle, the strain energy of a damaged element suddenly changes when structural damage occurs. Therefore, the change in the static shear energy is employed to determine the damage locations in beam-like structures. The static shear energy is derived from the spectral factorization of the elementary stiffness matrix and structural deflection variation. The advantage of using shear energy as opposed to total energy is that only a few deflection data points of the beam structure are required during the process of damage identification. Another advantage of the proposed approach is that damage detection can be performed without establishing a structural finite-element model in advance. The proposed technique is first validated using a numerical example with single, multiple, and adjacent damage scenarios. A channel steel beam and rectangular concrete beam are employed as experimental cases to further verify the proposed approach. The results of the simulation and experiment examples indicate that the proposed algorithm provides a simple and effective method for defect localization in beam-like structures.     

用于飞秒激光制备光纤光栅的相位掩模研制

利用严格耦合波理论分析了用于520 nm波长飞秒激光制备光纤光栅的相位掩模的衍射特性,当相位掩模是矩形槽形时,占宽比在0.32~0.43之间,槽形深度在0.57~0.67μm之间时,能够保证零级衍射效率抑制在2%以内,同时±1级的衍射效率大于35%。在此基础上,利用全息光刻-离子束刻蚀技术,制作了用于520 nm波长飞秒激光的周期为1067 nm、有效面积大于40 mm×30 mm的相位掩模。实际制作的相位掩模是梯形槽形,槽深是0.665μm,分析了梯形槽形中梯形角对衍射效率的影响。实验测量表明,该相位掩模的零级衍射效率小于2%,±1级衍射效率大于40%,满足飞秒激光制作光纤光栅的需要。     

基于LCP径向偏振光输出的掺镱MOPA脉冲光纤激光器

为实现光纤激光器径向偏振光的高效输出,提出并搭建了基于液晶聚合物(LCP)的纳秒脉冲掺镱(Yb)主振荡器功率放大(MOPA)系统。该系统采用空间相位转换法,利用LCP涡旋半波片将全光纤MOPA激光器输出的高峰值功率、窄线宽、线偏振、高斯形分布的纳秒脉冲信号转换为横向强度呈空心环状分布的拉盖尔-高斯光。MOPA激光器系统由窄线宽连续种子源、电光强度调制器和后续的5级YDF放大器组成,通过实验获得了20.1 W的稳定LP01模输出。而后的LCP涡旋波片用作空间模式转换器,最终获得的平均输出功率为19.5 W,脉宽为10 ns,重复频率为10 kHz,横向剖面呈规则空心环形的径向偏振光输出,模式转换效率可达97%。另外,通过PBS测量法测得径向偏振光的模式纯度约为88.5%,兼具高功率与高纯度的优势。     

矩形变截面单跨梁的内力计算公式和图表

本文推导了矩形变截面单跨梁的内力计算公式,并制成图表,便于结构计算中应用。     

某百货综合楼功能改造结构设计

提出了黑龙江省某百货综合楼功能改造的设计思想,给出了本工程功能改造结构设计的具体步骤,可供同类工程建设时参考。