摘要：Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell ***,traditional SOFCs suffer from having a higher volume,current leakage,complex connections,and difficulty in gas *** solve these problems,Rolls-Royce has fabricated a simple design by stacking cells in series on an insulating porous support,resulting in the tubular segmented-in-series solid oxide fuel cells(SIS-SOFCs),which achieved higher output *** work systematically reviews recent advances in the structures,preparation methods,perform-ances,and stability of tubular SIS-SOFCs in experimental and numerical ***,the challenges and future development of tubular SIS-SOFCs are also *** findings of this work can help guide the direction and inspire innovation of future development in this field.

摘要：动载荷识别在结构设计和优化中起着至关重要的作用目前的大多数研究都集中在确定性结构上.然而,实际工程结构中的结构参数是未知的.不确定参数的存在会导致载荷识别结果与实际载荷值之间的误差,因此研究不确定结构的动载荷识别问题至关重要的.本文针对含有不确定参数的结构,提出了一种数据驱动的动载荷识别方法.首先,将不确定参数由一组闭区间向量表征.然后引入卷积神经网络(CNN)对未知载荷区间进行重构.将区间分析理论与泰勒展开相结合,得到了监督载荷的上下边界,并将其用作训练样本.最后,训练后的CNN模型直接识别未知载荷区间的边界.仿真结果表明,该方法具有较高的载荷识别精度和对噪声的鲁棒性.我们构造了一个简支梁结构进行实验,以进一步验证所提出方法在工程中的可行性.此外,我们还讨论了测量点分布和样本数量对识别精度的影响,这有利于在工程实践中的应用。

摘要：The use of a reconfigurable intelligent surface(RIS)in the enhancement of the rate performance is considered to involve the limitation of the RIS being a passive *** address this issue,we propose a RIS-aided amplify-and-forward(AF)relay network in this *** jointly optimizing the beamforming matrix at AF relay and the phase-shift matrices at RIS,two schemes are put forward to address a maximizing signal-to-noise ratio(SNR)***,aiming at achieving a high rate,a high-performance alternating optimization(AO)method based on Charnes–Cooper transformation and semidefinite programming(CCT-SDP)is proposed,where the optimization problem is decomposed into three subproblems solved using CCT-SDP,and rank-one solutions can be recovered using Gaussian ***,the optimization variables in the CCT-SDP method are matrices,leading to extremely high *** reduce the complexity,a low-complexity AO scheme based on Dinkelbachs transformation and successive convex approximation(DT-SCA)is proposed,where the variables are represented in vector form,and the three decoupling subproblems are solved using *** results verify that compared to three benchmarks(i.e.,a RIS-assisted AF relay network with random phase,an AF relay network without RIS,and a RIS-aided network without AF relay),the proposed CCT-SDP and DT-SCA schemes can harvest better rate ***,it is revealed that the rate of the low-complexity DT-SCA method is close to that of the CCT-SDP method.

摘要：大型结构中的非线性关节对结构的影响是一类值得研究的重要问题.针对含大量非线性关节的平面周期结构,建立了一种基于高阶谐波的等效方法.首先,在单元层面上,非线性关节采用多谐波描述函数法进行建模,关节-梁-关节单元在动态缩聚后得到混合梁单元.然后,在结构层面上,使用位移等效原理获得平面周期结构的多谐波等效欧拉梁单元模型.其次,使用伪弧长法来跟踪频响函数的轨迹.之后,设计了一个实验来验证理论模型的正确性,同时考虑了悬挂系绳的影响和空气阻力.仿真结果揭示了这类含非线性关节周期结构的非线性特性与单自由度非线性系统特性的相似之处.最后,说明了在预测共振频率和幅值时考虑高阶谐波的重要性.

摘要：Wind machines have been increasingly applied to prevent frost damage through airflow disturbance in tea fields and *** impeller is the most important component of the ***,there are few studies on customized impeller design or airflow disturbance *** objective of this study was to design a new impeller for frost protection wind machines based on reverse engineering and CFD *** characteristic parameters of an impeller include blade cross-section shape,installation angle,sweep angle,hub ratio and blade *** optimal combination of the above parameters was obtained through the simulation of the impeller’s aerodynamic *** tests were conducted in a tea field to evaluate airflow disturbance performance of the designed *** result shows that at a certain rotation speed and rotation diameter,the optimal combination of impeller parameters was:single arc cross-section ofϕ2400 mm,installation angle of 15°,sweep angle of 87°,hub ratio of 0.3 and blade number of 4,of which the impeller could achieve the highest usage of 0.56,the least consumed power of 1.363 kW and more uniform distribution of surface pressure on the windward *** with other commercial frost protection wind machines,the maximum airflow velocity of the developed impeller was higher at 12 m in front of *** probability of airflow velocity above 3.0 m/s within 30 min was the highest(71.7%),indicating its improvement of airflow *** swing the new impeller could cover an effective area of 300 m2,which was similar to that of the commercial ones.

摘要：具有高且稳定离子输运特性的二维层状薄膜在纳米流体器件中具有广泛的应用,但是它们的构建仍然是一个相当大的挑战.本文设计并开发了一种超稳定的芳纶纳米纤维/石墨复合薄膜,其内部包含大量的一维和二维纳米受限空间,可以实现超快的离子传输.这种薄膜不仅具有良好的柔性和可拓展性,同时还表现出优异的力学性能,即使在水中浸泡90天仍具有高的拉伸强度(~115.3 MPa).并且该薄膜在低的盐浓度下具有表面电荷控制的离子输运特性,在10^(-4)mol/LKCl浓度下,其离子电导率相对于原始KCl溶液提高了16倍.最重要的是,即使在酸、碱、乙醇等极端环境中浸泡30天以上,薄膜的结构和离子电导率仍保持稳定.分子动力学模拟进一步揭示了薄膜的超稳定性是源于纳米纤维内部强大的链间作用以及纳米纤维与石墨纳米片之间强大的界面相互作用.这种柔性、可扩展、超稳定的芳纶纳米纤维/石墨复合薄膜可能为先进的纳米流体器件在不同极端工作环境下的应用提供一种有效的策略.

摘要：界面光热蒸发是一种高效的水蒸发技术,在太阳能海水淡化和水处理方面具有广阔的应用前景.光热蒸发器设计的一个重要部分是放置于光热蒸发表面和水体之间的隔热基底/支撑材料.这种典型的设计在二维(2D)蒸发体统中最大限度地减少了从蒸发表面到水体的热传递能量损失,从而将热量集中于蒸发表面以实现高效的光热蒸发.这种设计概念随后被直接应用于三维(3D)蒸发体系中.然而,与2D蒸发器只从太阳光获取能量不同的是,3D蒸发器还可以从空气和水中获取额外能量用于促进蒸发.在这种情况下,传统的隔热基底材料的使用是不合适的,因为它会阻碍蒸发器从水体中抽取能量.因此,本文重新对3D蒸发器进行了设计,使用了高导热材料来代替隔热材料来连接蒸发表面和水体.室内和户外测试均证实,通过使用高导热基底材料可以极大地提高蒸发性能.这一发现为设计3D光热蒸发器提供了新的思路.

摘要：开发具有良好的催化性能和稳定性的析氢反应(HER)和析氧反应(OER)的电催化剂对水分解产氢的商业化起着关键作用.本文通过简单、可扩展的腐蚀配位方法,将金属氢氧化物和金属有机骨架(MOF)组成的二维-三维(2D-3D)纳米结构原位装饰在泡沫Ni Fe (Pt-Ni Fe PBA)上.所设计的特殊形态有利于在电催化过程中提供丰富的活性位点、优化反应途径和加速传质.因此,合成的Pt-Ni Fe PBA在1 mol L;KOH中HER和OER在10 m A cm^(-2)时具有29和210 m V的过电位.值得注意的是,在10 m A cm^(-2)时该催化剂仅需21 m V即可驱动1 mol L;KOH海水,并具有出色的稳定性.此外,将合成的Pt-Ni Fe PBA用作双功能电催化剂时,只需1.46和1.48 V即可以达到10 m A cm^(-2).此外,间歇性的可持续能源,如热能、风能和太阳能可以为该水分解器提供动力.

摘要：界面太阳能光热蒸发是一种既有潜力又经济的海水淡化和废水处理技术.这种技术通过光热材料吸收太阳光,将太阳光转化为热能并将其集中于材料表面进行水蒸发.然而,界面光热蒸发系统由于蒸发过程中的热传导、热对流和热辐射能量损失,使光热蒸发的能量效率降低.因此,高效的能量管理对提高和优化光热蒸发效率至关重要.本文通过对光热材料以及冷、热蒸发表面的精心构筑,使蒸发器的光热蒸发性能得到显著的提升.这是由于这种结构能够同时实现降低体系能量损失,增加从环境中吸取能量,回收利用蒸汽冷凝释放的潜热以及热蒸发表面的热对流和热辐射能量损失.总体来说,通过这种新颖的能量管理策略,该光热蒸发装置的蒸发速度达到了2.94 kg m^-2h^-1,其能量转化效率超过了理论极限值.

摘要：The high incidence of cardiovascular disease has led to significant demand for synthetic vascular grafts in clinical ***-proliferation drugs are usually loaded into devices to achieve desirable anti-thrombosis effects after ***,the non-selectiveness of these conventional drugs can lead to the failure of blood vessel reconstruction,leading to potential complications in the long *** address this issue,an asymmetric membrane was constructed through electro-spinning *** bilayer membrane loaded and effectively released nitric oxide(NO),as hoped,from only one *** to the short diffusion distance of NO,it exerted negligible effects on the other side of the membrane,thus allowing selective regulation of different cells on both *** released NO boosted the growth of endothelial cells(ECs)over smooth muscle cells(SMCs)-while on the side where NO was absent,SMCs grew into *** overall structure resembled a native blood vessel,with confluent ECs as the inner layer and layers of SMCs to support *** addition,the membrane preserved the normal function of ECs,and at the same time did not exacerbate inflammatory *** preparing this material type that regulates cell behavior differentially,we describe a new method for its application in the cardiovascular field such as for artificial blood vessels.