摘要：探索具有高催化作用的活性中心结构,对于开发锂硫电池用单原子催化剂(SACs)至关重要.基于密度泛函理论计算,本工作提出了一种新型吡咯氮配位结构,用于负载3d过渡金属原子,以设计出高性能SACs.相比于传统的吡啶氮配位结构,该吡咯氮配位结构可实现对多硫化物更高的吸附及催化转化作用,从而提升锂硫电池活性物质的利用率、循环稳定性及倍率性能.基于对不同配位结构中的金属原子d轨道与多硫化物中硫原子p轨道杂化方式的分析,本工作阐明了吡咯氮配位结构可对多硫化物实现更强吸附作用的原因.此外,采用数据驱动的研究手段,探索出影响多硫化物催化转化效率的本征因素.因此,本工作提出了新型锂硫电池用SACs活性中心结构,并揭示了SACs的性能调控机制,为锂硫电池用SACs的设计提供了新策略.

摘要：这篇论文描述液化天然气(LNG ) 的特征搬运人简短。LNG 搬运人包括发电厂选择，蒸汽处理，液体货物坦克类型，等等。二 parametersfuel 替换率和气体(沼泽) 的沸腾的恢复体积到精力效率设计索引(EEDI ) 公式被增加，并且 LNG 搬运人的 EEDI 公式基于轮船 EEDI 被建立公式。基于 LNG 搬运人的蒸气汽轮机推进设备，然后， LNG 搬运人参考的数学模型排队价值在这篇论文被建立。由确认，在这份报纸描述的 LNG 搬运人的 EEDI 公式能为 LNG 搬运人 EEDI 计算和绿造船提供一本参考书。

摘要：这份报纸学习与被 overshoot 和安定时间决定的一些给定的短暂性能限制为平面系统的一个类追踪问题的输出。与产量限制(SSOFTOC ) 追踪的交换静态的产量反馈的问题第一次被建议并且解决。静态的输出反馈控制器和一条所谓的圆锥形的切换法律在没有违背短暂性能限制，靠近环的交换系统的输出能 asymptotically 在哪个下面追踪步信号下面被设计。而且，最佳的加权的短暂表演被解决一个非线性的编程问题获得。最后，到飞机扇涡轮引擎的一个数字例子和应用被给说明有效性和建议方法的适用性。

摘要：This paper develops a new method to the robust H_∞ control problem for a class of uncertain switched systems by constructing a single robust H_∞ sliding surface. The method consists of two phases. One is to construct a single sliding surface such that the reduced-order equivalent sliding motion restricted to the sliding surface is robustly stabilizable with H_∞ disturbance attenuation level γ under a hysteresis switching law; the other phase is to design variable structure controllers of subsystems to drive the state of the switched system to reach the single sliding surface in finite time and remain on it thereafter. A numerical example is given to illustrate the effectiveness of the proposed method.

摘要：Methods used for digital ship design were studied and formed the basis of a proposed frame model suitable for ship construction modeling. Based on 3-D modeling software, a digital design system for hull structures was developed. Basic software systems for modeling, modifying, and assembly simulation were developed. The system has good compatibility, and models created by it can be saved in different 3-D file formats, and 2D engineering drawings can be output directly. The model can be modified dynamically, overcoming the necessity of repeated modifications during hull structural design. Through operations such as model construction, intervention inspection, and collision detection, problems can be identified and modified during the hull structural design stage. Technologies for centralized control of the system, database management, and 3-D digital design are integrated into this digital model in the preliminary design stage of shipbuilding.

摘要：作为在许多设计应用程序的一个基本问题，到骚乱的从 laminar 的转变在计算液体动力学(CFD ) 仍然是一个困难的问题。一过渡流动在的数字研究二维被雷纳兹进行在这份报纸的平均数字模拟(RANS ) 。骚乱模型戏在复杂流动模拟的一个重要角色，和四个先进骚乱模型被评估。摩擦抵抗系数的数字答案与在过渡地区的测量那个相比，它显示有修正的那个威尔科克斯(2006 )k- 模型是最好的候选人。平均无尺寸的速度介绍的 streamwise 的无尺寸的速度表演的数字、分析的解决方案的比较在过渡区域很快改正形状。而且，象骚乱动能，旋涡粘性，和雷纳兹应力那样的骚乱数量也被学习，它是有用的学习转变行为。

摘要：目的:制荡挡板由于其安装方便并可以大幅减弱液舱半载时的晃荡效应而备受关注。本文基于试验验证的计算流体动力学方法,对环型挡板的制荡效应影响因素进行分析,以确定环形挡板中影响制荡效率的主要参数。创新点:1.通过正交设计与数值模拟的结合,得到影响环形挡板制荡效率的主要因素。2.结合正交试验的分析结果及环形挡板制荡机理数值分析,得出改进环形挡板制荡效率的方案。方法:1.通过物理试验对数值模拟方法进行验证;2.通过正交试验设计,制定环形挡板参数的数值试验表(表7),并根据计算结果,对参数的制荡效率影响进行分析(表8和9);3.对主影响参数进行重点分析,得出其制荡效率的变化规律(图19);4.对环形挡板的制荡机理进行分析,并对正交试验结果中各参数水平的影响进行验证。结论:1.环形挡板的高度、倾斜角度以及安装位置均对其制荡效率有显著影响,而环形挡板的厚度影响较小。2.环形挡板的4个参数中,高度因素的影响效果最显著,但是,当高度增至罐体直径的20%时,制荡效率提升速度变得不明显。3.相比于倾斜挡板会产生较多涡流耗散,当环形挡板处于竖直状态时,其较强的阻隔效应可以提供更多的制荡效果;挡板倾斜的方向对制荡效果有一定的影响,但该影响会随着倾斜角度的增大而减小。4.增大两个环形挡板的间距,将增加自由液面的长度,并延缓挡板约束流速的效率,从而减弱挡板的制荡效果。

摘要：Electrochemical CO2 reduction to chemicals or fuels presents one of the most promising strategies for managing the global carbon balance, which yet poses a significant challenge due to lack of efficient and durable electrocatalyst as well as the understanding of the CO2 reduction reaction(CO2RR) *** from the large surface area, high electrical conductivity, and tunable structure, carbon-based metal-free materials(CMs) have been extensively studied as cost-effective electrocatalysts for *** development of CMs with low cost, high activity and durability for CO2RR has been considered as one of the most active and competitive directions in electrochemistry and material *** this review article,some up-to-date strategies in improving the CO2RR performance on CMs are ***, the approaches to optimize the adsorption of CO2RR intermediates, such as tuning the physical and electronic structure are introduced, which can enhance the electrocatalytic activity of CMs ***, some design strategies are proposed to prepare CMs with high activity and selectivity for CO2RR.

摘要：The objective of steganography is to hide message securely in cover objects for secret *** to design a secure steganographic algorithm is still major challenge in this re-search *** this letter,developing secure steganography is formulated as solving a constrained IP(Integer Programming) problem,which takes the relative entropy of cover and stego distributions as the objective ***,a novel method is introduced based on BPSO(Binary Particle Swarm Optimization) for achieving the optimal solution of this programming *** results show that the proposed method can achieve excellent performance on preserving neighboring co-occurrence features for JPEG steganography.

摘要：在过去的十年中,推拉结构的有机小分子光伏材料由于分子带隙及光伏性能等易于实现有效的调控,在光伏领域中受到了广泛的关注.适宜的桥键联接对于提升有机太阳能电池的光伏性能起到了重要的作用.因此π-桥键在推拉结构的有机小分子设计中扮演着十分重要的角色.本文重点综述了推拉结构有机小分子的不同π-桥键(包括噻吩,烯烃,炔烃,芳烃和杂环及其相应的衍生物)对于材料的光伏性能所产生的重要影响.这些结果表明,深入的研究π-桥键效应对于深刻理解分子结构和材料性能之间的关系以及通过分子的结构优化来提高材料的光伏性能具有十分重要的意义.