摘要：有机共晶,由于其光热转换性质,为光热成像、生物应用和海水淡化等诸多领域带来了希望和活力.然而,有机共晶的光热转换机制尤其缺少详细且深入的理论研究.本研究使用含时密度泛函理论方法探索了激发和去激发过程,并解释了DBTTF-TCNB共晶比其组分单晶具有更高光热转换效率的原因.结果显示,高激发态的高占比促进了非辐射跃迁的发生.基于DBTTF-TCNB共晶中给电子基团和吸电子基团间的电荷转移结果,我们发现给体和受体之间吸引电子的竞争可能会促进光热转换,且给电子基团在共晶结构中也十分重要.这些结果可为光热转换共晶的设计提供理论指导.轨道贡献和电子密度差进一步证明了我们的结论.因此,本研究从量子化学的角度给光热共晶在创新领域的应用提供了理论依据.

摘要：Proton exchange membrane(PEM)fuel cell has been regarded as a promising approach to the decarbonization and diversification of energy *** recent years,durability and cost issues of PEM fuel cells are increasingly significant with the rapid increase of power ***,the failure to maintain the cell consistency,as one major cause of the above issue,has attracted little ***,this study intends to figure out the underlying cause of cell inconsistency and provide solutions to it from the perspective of multi-physics transport coupled with electrochemical *** PEM fuel cells with electrodes under two compression modes are firstly discussed to fully explain the relationship of cell performance and consistency to electrode structure and multi-physics *** result indicates that one main cause of cell inconsistency is the intrinsic conflict between the separated transport and cooperated consumption of oxygen and electron throughout the active ***,a mixed-pathway electrode design is proposed to reduce the cell inconsistency by enhancing the mixed transport of oxygen and electron in the *** is found that the mixing of pathways in electrodes at under-rib region is more effective than that at the under-channel region,and can achieve an up to 40%reduction of the cell inconsistency with little(3.3%)sacrificed *** addition,all the investigations are implemented based on a self-developed digitalization platform that reconstructs the complex physical–chemical system of PEM fuel *** fully observable physical information of the digitalized cells provides strong support to the related analysis.

摘要：利用光热材料吸收太阳能产生局域化的热效应实现太阳能蒸汽转化是一项环境友好型海水淡化和废水净化的技术.本文受自然界中叶片蒸腾作用的启发,设计了一种新型仿生叶片结构,以实现高效的太阳能蒸汽转化.这种新型仿生叶片结构由三个部分组成:(1)亲水性聚乙烯醇(PVA)海绵层(相当于叶子中的叶肉组织层),具有高孔隙率和低导热性;(2)聚吡咯(PPy)层(相当于叶子中的叶绿素层)负载于PVA海绵表面以吸收太阳能;(3)微/纳米尺度的多孔疏水表面层(相当于叶片中的气孔层).其中,亲水海绵的PVA聚合物网络提供了高效水传输通道的同时实现了内部水蒸发焓的降低;PPy层吸收太阳能并转化为内能加热气液蒸汽界面的水,实现热局部化,大大减小了热损耗;疏水性多孔表面层的边缘效应,为水蒸气提供了高效逃逸通道.基于仿生叶片结构的太阳能蒸汽转化装置在一倍太阳光强(1 kW m^(−2))下蒸发率高达3.09 kg m^(−2) h^(−1).在室外自然光照条件下成功地对盐水和海水进行了脱盐和净化,平均净水速率为1.4 L m^(−2) h^(−1).这种基于仿生叶片结构的太阳能蒸汽转化装置提供了一种极具潜力的高效水净化方法,有助于利用可持续能源缓解全球水危机.

摘要：光催化氧还原制备过氧化氢具有节能、环保等优点.然而,低活性以及低选择性的问题限制了其实际应用.基于金属离子耦合电子转移机制,本文通过浸渍-煅烧法合成了原子分散的钪路易斯酸位点修饰的氮化碳,光合成过氧化氢速率高达55μmol h^(-1),是氮化碳的6.2倍.光催化性能的提升归因于原子分散钪路易斯酸位点与·O_(2)^(-)结合,提高了O_(2)的得电子能力,减少了·O_(2)^(-)逆反应的发生,促进了氧还原反应进行.密度泛函理论模拟及Koutecky-Levich分析表明,钪原子的引入减少了O–O键的断裂,提高了合成过氧化氢的选择性.本研究提出了一种路易斯酸单金属位点光催化剂设计新概念,可同时提升催化反应活性及选择性.

摘要：这份报纸调查工具与 Lipschitz 条件和未知参数为非线性的系统的一个类设计观察员。完整顺序的州的适应观察员的一条新设计途径被建议。构造观察员能保证状态的错误和参数评价的错误 asymptotically 收敛到零。而且，一个数字例子被提供验证观察员的有效性。

摘要：We propose a method to bend a self-collimated beam in a photonic crystal. The beam bending relies on the gradual variation of the constitutive parameters of the photonic crystal. A new Y-shaped beam splitter is designed with a composite structure constructed using two graded photonic crystals. We demonstrate that the incident beam is divided into two output beams by the designed splitter. The power ratio of the two beams can be adjusted easily by changing the location of the input beam.

摘要：The nonlinear governing equations of the liquid sloshing modals in a cylindrical storage tank are established. Through analytical analysis, the analytical expressions of the solutions of this kind of system are obtained. With different parameters, the dynamical behaviors of the solutions are different from the trivial ones. To prevent system instability, two selection principles that the stiffness equations are positive-definite and the nonlinear terms of the system are not regenerative elements are given. Meanwhile, numerical simulations are also given, which confirm the analytical results.

摘要：用多重参考框架(MRF ) impeller 方法，一条双螺旋状的带子(DHR ) 产生的三维的非牛顿的流动地 impeller 被模仿了。数字模拟计算的速度地类似于以前的研究，力量常数与试验性的数据同意了很好。三计算液体动态(CFD ) 方法，标记我， II 和 III，被用来计算 Metzner 经常的 ks。结果证明从 slop 方法的计算价值(方法我) 与试验性的数据一致。方法 II，它拿了最大的圆周一般水准砍在是的 impeller 附近的率有效砍计算 ks 的率，对实验的也显示出的好同意。然而，两个方法受不了计算过程的复杂性。一个新方法(方法 III ) 在这份报纸被设计为精明的 ks 在 impeller 附近把区域加权的平均粘性用作有效粘性。方法 III 显示出好精确性和容易使用。

摘要：本文提出了由之字形单元组成的弹性波超构表面来实现对弯曲波的深亚波长尺度操控.通过遗传算法对单元进行参数优化,可以找到具有全透射率和全相位控制的单元,而其宽度仅为波长的1/5.结合传输模态和Kirchhoff薄板理论,发展了理论模型并解释了这些单元产生优越性能的原因.接着,设计了直线型和曲线型超构表面实现不同位置的弯曲波聚焦,其仿真结果都显示出了优异的性能,进一步加工制作直线型超构表面并进行实验测试,实验结果与仿真结果非常吻合,结果同时表明入射波能量在焦点处提高了6倍以上.本工作提出的超构表面可用于设计紧凑高效的弹性波器件.

摘要：富锂层状氧化物是构筑高能量密度锂离子电池富有潜力的正极材料.然而,由于不可逆的结构变化和缓慢的界面动力学,传统的多晶富锂层状氧化物正极材料循环和倍率性能较差.本文提出了一种聚乙烯基吡咯烷酮(PVP-K30)辅助共沉淀制备单晶Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)纳米片的方法.这种方法操作简单、成本低且便于放大生产.所制备的单晶纳米片内部晶格连续且无晶界,缩短了Li+的嵌入/脱嵌路径,加快了电极反应动力学过程.单晶结构还能抑制层状相向尖晶石相的不可逆相变和颗粒内部裂纹的形成,起到稳定层状结构的作用.电化学测试结果表明,所制备的Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)单晶纳米片在0.1 C倍率下的可逆容量为254.5 mA h g^(-1),在5 C高倍率下循环1000次后容量保持率为71.9%.这种简单的制备纳米片单晶材料的方法为提高富锂层状氧化物正极材料的循环性能和倍率性能提供了新的思路.