箱形梁结构船体水下非接触爆炸冲击环境分析

为研究箱形梁结构船体在水下非接触爆炸作用下的冲击环境,在船体中部范围内主要受力部位设置箱形梁,并与考虑箱形梁产生的质量变化而建立的等重船模进行对比,来描述箱形梁结构对冲击环境的影响.基于Abaqus中的声固耦合算法求解2种形式船体的冲击响应,以冲击谱为工具描述船体结构的冲击环境,并给出舱内甲板层的冲击环境分布.分析归纳箱形梁的作用机理,为相关舰船设备的舾装与船体优化设计提供参考.     

Nonconfinement Structure Revealed in Dion–Jacobson Type Quasi‐2D Perovskite Expedites Interlayer Charge Transport

Dion–Jacobson (DJ) type 2D perovskites with a single organic cation layer exhibit a narrower distance between two adjacent inorganic layers compared to the corresponding Ruddlesden–Popper perovskites, which facilitates interlayer charge transport. However, the internal crystal structures in 2D DJ perovskites remain elusive. Herein, in a p‐xylylenediamine (PDMA)‐based DJ perovskite bearing bifunctional NH₃⁺ spacer, the compression from confinement structure (inorganic layer number, n = 1, 2) to nonconfinement structure (n > 3) with the decrease of PDMA molar ratio is unraveled. Remarkably, the nonconfined perovskite displays shorter spacing between 2D quantum wells, which results in a lower exciton binding energy and hence promotes exciton dissociation. The significantly diminishing quantum confinement promotes interlayer charge transport leading to a maximum photovoltaic efficiency of ≈11%. Additionally, the tighter interlayer packing arising from the squeezing of inorganic octahedra gives rise to enhanced ambient stability.     

Unravelling H+/Zn2+ Synergistic Intercalation in a Novel Phase of Manganese Oxide for High‐Performance Aqueous Rechargeable Battery

Aqueous Zn‐MnO₂ batteries using mild electrolyte show great potential in large‐scale energy storage (LSES) application, due to high safety and low cost. However, structure collapse of manganese oxides upon cycling caused by the conversion mechanism (e.g., from tunnel to layer structures for α‐, β‐, and γ‐phases) is one of the most urgent issues plaguing its practical applications. Herein, to avoid the phase conversion issue and enhance battery performance, a structurally robust novel phase of manganese oxide MnO₂H_0.16(H₂O)_0.27 (MON) nanosheet with thickness of ≈2.5 nm is designed and synthesized as a promising cathode material, in which a nanosheet structure combined with a novel H⁺/Zn²⁺ synergistic intercalation mechanism is demonstrated and evidenced. Accordingly, a high‐performance Zn/MON cell is achieved, showing a high energy density of ≈228.5 Wh kg^?1, impressive cyclability with capacity retention of 96% at 0.5 C after 300 cycles, as well as exhibiting rate performance of 115.1 mAh g^?1 at current rate of 10 C. To the best current knowledge, this H⁺/Zn²⁺ synergistic intercalation mechanism is first reported in an aqueous battery system, which opens a new opportunity for development of high‐performance aqueous Zn ion batteries for LSES.     

电动汽车冬季负荷特性研究

纯电动汽车在冬季运行时,其采暖负荷将造成续航里程严重缩短。因此,确定电动汽车空调在冬季时的负荷特性对于指导设计和控制尤为重要。对此本文使用热平衡法对电动汽车稳态负荷特性进行了实验研究,结果发现:冬季采暖负荷主要由新风负荷与车体围护结构导热负荷构成,其中新风负荷占主要部分,该负荷随车速、及鼓风机风量的增加而增加。在-20℃环境中,随车速及鼓风机档位变化,新风负荷占比为56.2%~84.8%。基于此,进一步分析计算了冬季采暖负荷及制热效率对于纯电动汽车的里程影响:NEDC工况下,冬季使用PTC取暖将会使得续航里程下降20.1%~56.4%,而使用热泵将显著延长续航里程,当热泵效率为1.7时,可延长里程7.4%~13.2%。     

Nanozyme-Engineered Bioglass through Supercharged Interface for Enhanced Anti-Infection and Fibroblast Regulation

Effective therapy of infection impaired tissue defects has long been an important but challenging topic, and alternative antibiotic-free solutions are greatly demanded to tackle bacterial infections and promote tissue repair. Herein, the use of supercharged gold nanoclusters (AuNCs) with enhanced enzyme mimic activity as novel interface modulator of bioactive glass nanoparticles (BGN) for infected wound treatment is reported. The supercharged AuNCs exhibit extraordinary affinity toward BGN, leading to the robust immobilization of AuNCs on BGN (BGN-AuNCs). Functional AuNCs endow BGN with superior peroxidase-like activity for catalytic antibacterial action, which can kill bacteria with a concentration down to 75 µg mL⁻¹ within 6 h due to the production of highly toxic ·OH. Moreover, expression level of COL-1, TGF-β, and FGF-2 in fibroblasts is actively up-regulated to 2.9, 3.1, and 1.6 times higher than that of control group due to the positive effect of BGN-AuNCs on cell proliferation. Meanwhile, intrinsic photoluminescent property of AuNCs enables the direct visualization of BGN at both in vitro and in vivo levels for potentially bioimaging-guided therapy. Further in vivo results demonstrate that BGN-AuNCs hold enormous promise for infectious disease therapy and pro-regeneration, and the proposed supercharged interface engineering strategy is attractive for developing advanced functional nanomedicines.     

Hierarchical Chiral Self-Assembly of Lead Halide Perovskite Nanocrystals by Oriented Phase Transition

Self-assembly of lead halide perovskite nanocrystals (NCs) into close-packed, long-range-ordered nanostructures can effectively modulate their photoelectronic properties, yet significantly challenging. Herein, an efficient approach is reported to induce the hierarchical self-assembly of perovskite CsPbBr₃ NCs by phase transition using chiral cysteine ligands, yielding asymmetric Cs₄PbBr₆ nanorods (NRs) with the circularly polarized luminescent response. An interfacial phase transition process is found during the conversion of CsPbBr₃ nanocubes to Cs₄PbBr₆ NCs initiated by cysteine molecules. Then the Cs₄PbBr₆ NCs aggregate sequentially to form nanoclusters, which further self-assemble into the chiral Cs₄PbBr₆ NRs. Molecular dynamics simulations reveal that the Cs₄PbBr₆ nanochains gradually approach each other to achieve an asymmetric structure, and the simulated circular dichroism spectrum further supports the formation of a chiral structure. This work offers a facile method for the hierarchical chiral self-assembly of lead halide perovskite nanostructures, which brings new insights to explore chiral nanostructures by modulating the surface chemistry and post self-assembly.     

Nonpolar Cosolvent Driving LUMO Energy Evolution of Methyl Acetate Electrolyte to Afford Lithium-Ion Batteries Operating at −60 °C

The operation of lithium-ion batteries (LIBs) at low temperatures (<−20 °C) is hindered by the low conductivity and high viscosity of conventional carbonate electrolytes. Methyl acetate (MA) has proven to be a competitive low-temperature electrolyte solvent with low viscosity and low freezing point, but its interfacial stability is poor and remains elusive until now. Here, it is revealed thaat the reductive stability of MA-based electrolytes is fundamentally governed by the anion-prevailed solvation structure. Based on this framework, fluorobenzene is employed in the electrolyte to promote the entry of anions into the solvation shell via dipole-dipole interactions and the generation of free MA, thus enhancing the lowest unoccupied molecular orbital energy of MA. The designed electrolyte enables LiCoO₂ (LCO)/graphite cells to exhibit excellent cycling performance at −20 °C (90% retention after 1000 cycles at 1 C) and to remain 91% of their room-temperature capacity at a super-low temperature of −60 °C at 0.05 C. Thanks to the plentiful free MA, this electrolyte has a high conductivity (2.61 mS cm⁻¹) at −60 °C and allows LCO/graphite cell to charge at −60 °C. This study offers the possibility of practical applications for those solvents with poor reductive stability and provides new approaches to designing advanced electrolytes for low-temperature applications.     

生成对抗网络下的低剂量CT图像增强

为去除低剂量计算机断层扫描（LDCT）图像中的噪声,增强去噪后图像的显示效果,提出一种生成对抗网络（GAN）下的LDCT图像增强算法。首先,将GAN与感知损失、结构损失相结合对LDCT图像进行去噪;然后,对去噪后的图像分别进行动态灰度增强和边缘轮廓增强;最后,利用非下采样轮廓波变换（NSCT）将增强后的图像在频域上分解为具有多方向性的系数子图,并将配对的高低频子图使用卷积神经网络（CNN）进行自适应融合,以重构得到增强后的计算机断层扫描（CT）图像。使用AAPM比赛公开的真实临床数据作为实验数据集,进行图像去噪、增强、融合实验,所提方法在峰值信噪比（PSNR）、结构相似度（SSIM）和均方根误差（RMSE）上的结果分别为33.015 5 dB、0.918 5和5.99。实验结果表明,所提算法在去除噪声的同时能保留CT图像的细节信息,提高图像的亮度和对比度,有助于医生更加准确地分析病情。     

考虑信息时移的分布式光伏机理-数据混合驱动短期功率预测

分布式光伏短期功率预测缺乏同时空气象数据。传统方法直接借助邻近集中式光伏站点数据进行功率预测,忽略了地理位置偏移带来的气象信息时移,难以满足预测精度要求。文中提出了一种考虑气象信息时移的混合预测方法。在机理驱动模型中,采用最优时移对气象数据进行偏移修正;在数据驱动模型中,引入时间模式注意力机制削弱气象数据偏移的影响。然后,通过Stacking集成学习框架将两种方法进行融合,形成机理-数据混合驱动模型,进一步提高预测稳定性及准确率。基于分布式光伏和公共气象站点实际数据进行的案例分析表明,所提方法能够有效利用偏移地理位置的气象数据,实现更高精度的分布式光伏发电功率预测。     

基于改进人工蜂群算法的区域电网储能系统能量管理优化策略

为提高新能源消纳水平及系统运行效率,需对储能系统充放电功率进行优化,以平抑功率波动,降低网络损耗,提高经济效益。基于源荷状态判断储能各时段充放电状态,以区域日网损降低收益、日高储低放套利收益及日环境效益最大为目标,综合考虑储能自身约束及网架潮流状态约束等条件,建立了区域电网储能能量管理优化模型。求解过程中提出了一种改进人工蜂群算法（improved artificial bee colony,IABC）,并针对吐鲁番区域网架结构及运行特点进行了建模仿真。结果表明,对储能进行能量管理优化可提升整体经济效益,且改进人工蜂群算法具有很好的全局搜索能力及收敛性。