Electrophoretic deposition of ZnCo2O4 spinel and its electrocatalytic properties for oxygen evolution reaction

In this paper, ZnCo₂O₄ was deposited on nickel substrate by electrophoretic deposition (EPD) method as electrocatalyst for the oxygen evolution reaction. The effect of electrophoresis variables including the deposition time, the applied voltages was discussed. XRD, SEM, and electrochemical measurement techniques were used to characterize the deposit and ZnCo₂O₄/Ni electrode. Compared with the ZnCo₂O₄ electrode prepared by nitrate decomposition method, the electrophoretic ZnCo₂O₄ electrodes exhibit better electrocatalytic properties and higher mechanical stability. And the electrode prepared at 10 V for 5 min has the best electrocatalytic properties with the overpotential of only 0.203 V at current density of 100 mA cm⁻².     

基于混沌粒子群的多飞艇资源配置规划方法

对地观测具有任务繁多、约束复杂、资源有限等特点,对观测资源配置进行合理规划具有重要意义。面向多飞艇多载荷对地观测任务,结合经典粒子群算法,研究了满足任务完成度、分辨率要求和负载均衡度等多目标的资源配置规划方法。在经典粒子群算法的基础上利用混沌优化技术进行改进,并设计实现了原型系统。实验验证了该资源配置规划方法的有效性。     

Variational PCA fusion for resolution Pan-sharpening very high imagery

The Pan-sharpening approach based on principle component analysis （PCA） is affected by severe spectral distortion. To address this problem, a new pan-sharpening model based on PCA and variational technique is proposed to construct the substitute image of the first principal component （PC1）. The energy functional consists of three terms. The first term injects PC1 with the geometric structure of the panchromatic （Pan） image. The second term preserves the spectral pattern of the multi-spectral image in the merged result. And the third term guarantees the smoothness of the functional optimization solution. The fusion result is given by the minimum of the energy functional, which is computed with the gradient descend flow. The experiments on QuickBird and IKONOS datasets validate the effectiveness of the proposed model. Compared with the state- of-the-art pan-sharpening approaches, this model exhibits a better trade-off between improving spatial quality and preserving spectral signature of the MS image.     

Towards evolvable Internet architecture-design constraints and models analysis

There is a general consensus about the success of Internet architecture in academia and industry. However, with the development of diversified application, the existing Internet architecture is facing more and more challenges in scalability, security, mobility and performance. A novel evolvable Internet architecture framework is proposed in this paper to meet the continuous changing application requirements. The basic idea of evolvability is relaxing the constraints that limit the development of the architecture while adhering to the core design principles of the Internet. Three important design constraints used to ensure the construction of the evolvable architecture, including the evolvability constraint, the economic adaptability constraint and the manageability constraint, are comprehensively described. We consider that the evolvable architecture can be developed from the network layer under these design constraints. What＇s more, we believe that the address system is the foundation of the Internet. Therefore, we propose a general address platform which provides a more open and efficient network environment for the research and development of the evolvable architecture.     

Experimental study on temperature stress calculation and temperature control optimization of concrete based on early age parameters

Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With the simulation testing machine for the temperature stress,in the present study,we carried out the deformation process tests of concrete under three temperature curves：convex,straight and concave.Besides,we not only measured the early-age elastic modulus,creep parameters and stress process,but also proposed the preferred type.The results show that at early age,higher temperature always leads to greater elastic modulus and smaller creep.However,the traditional indoor experiments have underestimated the elastic modulus and creep development at early age,which makes the calculated value of temperature stress too small,thus increasing the cracking risk.In this study,the stress values of the three curves calculated based on the strain and early-age parameters are in good agreement with the temperature stress measured by the temperature stress testing machine,which verifies the method accuracy.When the temperature changes along the concave curve,the law of stress development is in consistent with that of strength.Under this condition,the stress fluctuation is small and the crack prevention safety of the concave type is higher,so the concave type is better.The test results provide a reliable basis and support for temperature control curve design and optimization of concrete dams.     

激光谐振腔内倾斜误差的自适应校正

我们设计制作了一种性能良好的倾斜镜,试验了两种校正系统:微机控制的试探爬山法系统和高频振动爬山法系统。实验结果表明,这两种校正系统,都可以成功地校正腔内倾斜误差。最后,比较了两种校正系统的优缺点。     

钢框架-钢板剪力墙结构修复后的使用性能指标

为便于钢框架-钢板剪力墙结构震后快速修复,统计既有实验结果,提出修复后使用的三级性能指标,基于等效拉杆理论,研究结构在侧向载荷作用下塑性铰的出现顺序、层间位移角和结构应力发展等情况,并建立有限元模型对指标进行验证.结果 表明:在一级修复性能指标(位移角1/220)下,结构板墙轻微受损,对应的修复方法为对板墙进行轻微修复;在二级修复性能指标(位移角1/110)下,结构板墙几乎全面进入塑性状态,需要考虑换板或增加加劲肋修复;在三级修复性能指标(位移角1/85)下,结构板墙已经全部进入屈服状态,而且框架梁端也出现塑性铰,此时不仅需要对板墙进行修复,还要考虑对框架进行修复.     

基于RISC-V处理器的卷积加速SoC系统设计

为提高卷积神经网络（CNN）的计算效率和能效,以8 bit定点数据作为输入,设计一个支持激活、批标准化以及池化等CNN网络中常见计算类型的卷积加速器,优化循环计算顺序并将其与数据复用技术相结合,以提高卷积计算的效率。基于软硬件协同设计思想,构建包含RISC-V处理器和卷积加速器的SoC系统,RISC-V处理器基于开源的指令集标准,可以根据具体的设计需求扩展指令功能。将该SoC系统部署在Xilinx ZCU102开发板上,RISC-V处理器和卷积加速器分别工作在100 MHz和300 MHz频率下,测试结果表明,该加速器的算力达到153.6 GOP/s,运行VGG16网络进行图片推理计算时加速效果较好。     

认知任务驱动的fMRI脑功能网络构建方法

针对脑功能网络的构建受到特定大脑图谱对兴趣点描述准确度及覆盖度的限制,提出了基于认知任务信息和神经影像数据的脑功能网络构建方法。首先计算fMRI体素对于认知任务的敏感度,然后在此基础上选取兼顾分布均衡和去中心化的大脑兴趣点,从而构建任务驱动的脑功能网络。实验通过在人脸情绪识别认知任务相关的梭状回构造任务驱动的脑功能网络,其度中心性、聚类系数、全局效率、局部效率这四个复杂网络指标均优于典型大脑图谱梭状回中兴趣点构成的网络。结果表明,计算得到的大脑兴趣点具有更强的整合性,更适合用于表征特定认知任务下的脑功能网络。     

一种可追溯的比特币混淆方案

混淆技术是以比特币为代表的数字货币隐私保护的重要手段,然而,比特币中的混淆技术一方面保护了用户隐私,另一方面却为勒索病毒、比特币盗窃等非法活动提供了便利.针对该问题,提出了一种可追溯的比特币混淆方案,该方案旨在保护合法用户隐私的同时,可对非法资产混淆进行追溯.该方案在中心化比特币混淆基础上引入可信第三方分发用户签名密钥与监管混淆过程,用户签名密钥由基于双线性群和强Diffie-Hellman假设的群签名算法构造,以提供签名的匿名性与可追溯性.当有资产追溯需求时,可信第三方通过系统私钥打开用户签名以确定混淆输出地址,从而确定非法资产转移路径.安全分析表明,该方案不用修改当前比特币系统数据结构即可实施,可对非法资产混淆转移路径进行追溯,同时保护合法用户隐私与资产安全,且可抗拒绝服务攻击.此外,该方案为数字货币隐私保护研究提供了参考方向.