Simultaneous CO2 and H2O Activation via Integrated Cu Single Atom and N Vacancy Dual-Site for Enhanced CO Photo-Production

Photocatalytic conversion of CO₂ into fuels using pure water as the proton source is of immense potential in simultaneously addressing the climate-change crisis and realizing a carbon-neutral economy. Single-atom photocatalysts with tunable local atomic configurations and unique electronic properties have exhibited outstanding catalytic performance in the past decade. However, given their single-site features they are usually only amenable to activations involving single molecules. For CO₂ photoreduction entailing complex activation and dissociation process, designing multiple active sites on a photocatalyst for both CO₂ reduction and H₂O dissociation simultaneously is still a daunting challenge. Herein, it is precisely construct Cu single-atom centers and two-coordinated N vacancies as dual active sites on CN (Cu₁/N_2CV-CN). Experimental and theoretical results show that Cu single-atom centers promote CO₂ chemisorption and activation via accumulating photogenerated electrons, and the N_2CV sites enhance the dissociation of H₂O, thereby facilitating the conversion from COO* to COOH*. Benefiting from the dual-functional sites, the Cu₁/N_2CV-CN exhibits a high selectivity (98.50%) and decent CO production rate of 11.12 µmol g⁻¹ h⁻¹. An ingenious atomic-level design provides a platform for precisely integrating the modified catalyst with the deterministic identification of the electronic property during CO₂ photoreduction process.     

Poly(pentahydropyrimidine)-Based Hybrid Hydrogel with Synergistic Antibacterial and Pro-Angiogenic Ability for the Therapy of Diabetic Foot Ulcers

Bacterial infection and impaired angiogenesis make the treatment of diabetic foot ulcers (DFU) extremely challenging. Cationic polymers are expected to treat infected wounds due to their excellent antibacterial properties, but still, it is difficult to meet the therapeutic needs of pro-angiogenesis and anti-infections due to their simple construction units and outmoded synthesis methods. Herein, a cationic poly(pentahydropyrimidine) (PPHP) library with strong modifiability is synthesized to construct a hybrid hydrogel with synergistic therapeutic effects for the treatment of infected DFUs. It is found that the as-synthesized hybrid hydrogel can up-regulate angiogenesis-related gene (HIF-1, VEGF, and bFGFR/bFGF) expression and targeted disruption of bacterial cell membranes, which finally promotes the healing of infected DFU (wound healing rate: 92%) within 10 days. This hydrogel, thus, holds great promise in developing new strategies to significantly enhance the treatment of DFU and other bacterial-infected pathological diagnoses.     

武器装备采办风险动态评估模型研究

文中提出了一种基于模糊层次分析方法的武器装备采办风险动态评估模型,该模型采用三角模糊数与层次分析法相结合的原则来确定各级风险指标和武器装备采办各阶段的权重,通过建立模糊评判矩阵RE来表征各风险指标的风险水平,更为关键的是该模型能够对整个武器装备采办过程中风险状态实现动态评估,从而为制定科学合理的武器装备采办风险决策提供决策依据,使得风给管理决策更为具有针对性、实效性和准确性.     

钪锆微合金化焊丝焊接头的组织与性能

用ER5356铝镁合金焊丝和用钪和锆复合微合金化的铝镁合金焊丝对7A52铝合金板材进行手工钨电极惰性气体保护焊,随后对焊接接头的显微组织和力学性能进行了研究。结果表明,7A52铝合金焊接接头的力学性能低于基板的性能,焊缝区和热影响区是焊接接头上两个最薄弱的区域。用钪和锆复合微合金化的铝镁基合金焊丝与ER5356铝镁合金焊丝比较焊接,板材焊接接头的屈服强度和延伸率分别提高了24%和37%,分析认为其强化和韧化的机制主要是含钪和锆的化合物粒子的晶粒细化作用及其弥散强化作用。     

光纤陀螺在潜艇导航中的应用初探

光纤陀螺(FOG)与GPS结合组成惯性导航系统,其光纤陀螺精度高适用于潜艇导航、战术/战略导航控制.光纤陀螺仪及其导航系统作为新一代精确惯性导航系统用于潜艇导航,并将全面取代传统惯性与静电陀螺(SEG)潜艇导航.     

量化误差分析与信号重建

针对航空航天和通信领域广泛存在的量化误差,以遥测信号为研究对象,提出了量化误差抑制的节省参数建模和时频分离方法,实现高精度的信号重建.首先分析等距节点样条模型和自由节点样条模型对带量化噪声信号重建的影响;其次研究量化噪声与信号的近似正交性,并建立节省参数模型,由数字信号恢复原始模拟信号.计算结果表明,观测数据通过节省参数建模和时频分离技术处理以后,信号估计的精度得到了有效地提高.     

基于神经网络的导弹惯性器件故障预报系统研究

在导弹武器系统当中,及时准确地故障预报对提高导弹的安全性具有极其重要的意义.针对导弹惯性器件故障预报系统的设计要求,考虑到神经网络用于故障预报的优点,在神经网络技术应用于导弹惯性器件的故障预报过程中提出了神经网络的训练算法,把神经网络、预测理论和故障诊断系统有机结合起来建立了一个故障预报系统,利用该系统选取神经网络预测模型对某导弹陀螺随机漂移进行建模和分析,实现了故障预报.实例预测结果证明,给出的神经网络预测模型和训练算法是可行的.     

电视台非线性节目制作网的安全性设计

本文结合天津电视台非线性节目制作网的建设过程,分析了非线性制作网络的主要故障,并针对故障原因,介绍和分析该非线性制作网络一系列高可用性、安全性的设计方案.     

SU-8胶曝光衍射效应的模拟及丙三醇补偿方法

基于SU-8胶的UV-LIGA技术是MEMS中制备高深宽比结构的一种重要方法,但由于衍射效应会使结构的侧壁不再垂直.根据菲涅耳衍射模型,考虑了丙三醇/SU-8界面的反射和折射现象,模拟了丙三醇填充在掩膜版和光刻胶之间时的刻蚀图形.计算结果与已有的实验进行了比较,模型基本可以描述这种光刻过程,可在设计时作为参考.     

海底观测网连通可靠性分析

归纳了一种通用的水下节点光通信模型,引入节点存活率作为海底观测网的可靠性指标,针对水下多分支节点较多导致的可靠性降低和铺设施工难度增加等缺点,将NEPTUNE优化为只包含两个多分支节点的交叉环拓扑。对上述两种网络的可靠性进行了仿真,结果表明,交叉环拓扑与NEPTUNE相比具有相近的可靠性,但多分支节点数量更少,便于海底观测网的供电和铺设。