摘要：Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed compositions,and varied *** electron microscopy(TEM)as well as its aberration correction techniques are powerful for characterizing SROs in these compositionally complex *** this short communication,we summarized recent progresses regarding characterization of SROs using TEM in the field of *** using advanced TEM techniques,not only the existence of SROs was confirmed,but also the effect of SROs on the deformation mechanism was ***,the perspective related to application of TEM techniques in HEAs are also discussed.

摘要：对高速边界层转捩与湍流的理解、建模与控制不但具有广泛的学术兴趣,而且对高速飞行器的设计与节能有至关重要的意义,因为转捩和湍流会急剧增加壁面摩阻和热流.根据Morkovin假设,高速流动具有一些与不可压缩流动本质上相似的特征,但另一方面,由于存在热力学过程、激波、高焓效应等多物理场耦合,与不可压缩流动也有显著区别.本文综述了高速边界层转捩与湍流的物理和建模方面的最新研究进展,其中较大部分内容为湍流研究.为了物理过程描述的完整性,我们首先简要综述了高速流动转捩,主要关注气动加热原理和推迟转捩的被动控制策略.随后,我们总结了近期在湍流平均流向速度和温度的标度率方面的一些令人鼓舞的发现,这些标度率能够用于构建一系列新颖的壁面模型以提高模式精度.此外,作为湍流建模的基础之一,我们还总结了湍流结构方面的研究,尤其关注边界层对数区含能运动的标度率与建模.另外,我们综述了各种用于预测壁湍流的线性模型.尽管湍流通常被认为是高度非线性的,这些线性模型在过去二十年的研究中取得了较大的成功.最后,我们对综述进行总结,并简要展望未来研究.

摘要：Robotic subsea stratum drilling robot is a method for new subsea stratigraphic geological investigation and resource *** at the front end is the main source of resistance to the robot’s motion in the *** there is no continuous and strong downward drilling force as in conventional drilling rigs,robot movement relies heavily on the drill bit to reduce the drilling *** this study we propose a self-propelling drill bit that can discharge soil debris to provide propulsive force and reduce the *** key parameter of the drill bit design,the spiral blade lead angle,was determined by theoretical analysis of the drill bit’s soil discharging *** verify the structural advantages of the self-propelling drill bit in reducing resistance,a comparative analysis with a conventional conical drill bit was *** drilling process of both bits was simulated using finite element simulation at various rotation speeds,the penetration force and torque data of both drill bits were obtained,and tests prepared accordingly in subsea soil were *** simulations and tests verified that the penetration force of the self-propelling drill bit was lower than that of the conventional conical drill *** self-propelling drill bit can reduce the resistance effectively,and may play an important role in the stratum movement of drilling robots.

摘要：长寿命溶解氧海水电池是深远海观测能源网络的重要组成单元,但海水贫氧复杂环境对设计高性能氧还原催化剂提出了重要挑战.本文以酞菁铁为模型催化剂,通过理论计算与实验验证,提出了活性位点电子轴向拉伸可大幅提升催化剂在极端贫氧环境中的氧还原活性和稳定性.该研究为构建高性能海水电池提供了材料学解决方案,同时为极端环境下催化剂的变革性设计提供了新的思路.

摘要：A new method of virtual ship assembly modeling which integrates ship three-dimensional design and ship construction planning was described in this paper. A workflow model of simulation modeling based on the virtual ship assembly process was also established; furthermore, a method of information transformation between the ship three-dimensional design and ship construction plan was formulated. To meet the requirements of information sharing between different systems in the ship virtual assembly, a simulation database was created by using the software engineering design method and the relational data model. With the application of this database, the information of ship three-dimensional design, construction planning, and virtual assembly can be integrated into one system. Subsequently, this new method was applied as a tool to simulate the virtual assembly of a ship, and the results guarantee its rationality and reliability.

摘要：In this study,a 3D virtual reality and visualization engine for rendering the ocean,named VV-ocean,is designed for marine *** design goals of VV-ocean aim at high fidelity simulation of ocean environment,visualization of massive and multidimensional marine data,and imitation of marine ***-ocean is composed of five modules,*** management module,resources management module,scene management module,rendering process management module and interaction management *** are three core functions in VV-ocean:reconstructing vivid virtual ocean scenes,visualizing real data dynamically in real time,imitating and simulating marine lives *** on VV-ocean,we establish a sea-land integration platform which can reproduce drifting and diffusion processes of oil spilling from sea bottom to *** factors such as ocean current and wind field have been considered in this *** this platform oil spilling process can be abstracted as movements of abundant oil *** result shows that oil particles blend with water well and the platform meets the requirement for real-time and interactive ***-ocean can be widely used in ocean applications such as demonstrating marine operations,facilitating maritime communications,developing ocean games,reducing marine hazards,forecasting the weather over oceans,serving marine tourism,and so ***,further technological improvements of VV-ocean are discussed.

摘要：层状双金属氢氧化物(LDHs)作为一种类水滑石薄膜,以其优异的特性在许多领域中具有广泛的应用.然而,现有的LDH膜制备路线具有大规模生长受限和不可控等问题.本文中,我们受一种草本植物“落地生根”(Bryophyllum Pinnatum)具有肆意生长特性的启发,首次引入可牺牲的共溅射锌-铝中间层作为“植物种子”,通过“局部溶解”和“溶液渗透”的结构转化机制在任意形状、大小及材质的基底材料上实现大规模、厚度可控的LDH膜制备.通过调控中间膜的成分、结构和表面形貌,设计具有不同特性的LDH转化膜.实验结果表明,所制备的LDH膜具有较大的厚度和多级微观结构的特性,在严苛的磨损条件下仍能实现良好的机械稳定性.另外,我们设计了一系列基于锌-铝单金属中间层的电偶模拟实验对LDH膜的化学转化机理进行了深入探究,解决了传统复杂水热过程中实时监测困难的问题.本工作不仅开发了一种制备具有多尺度特性的LDH转化膜的新策略,同时揭示了复杂的LDH原位转化机理,为拓宽LDH材料在先进智能材料上的实际应用提供了新的发展思路.

摘要：本文研究了欠驱动自主式水下航行器在具有参数不确定、环境干扰以及输入饱和受限下的三维轨迹跟踪控制问题。首先,基于跟踪误差运动学,建立的虚拟导航控制律将整个控制系统分解成两个级联子系统。其次,引入一阶滑模微分器避免求导过程中复杂的解析计算,并考虑基于高斯误差函数的连续可微对称饱和模型处理输入约束问题。借助反步法设计法,神经网络控制方法以及自适应控制策略,估计未知不确定项和逼近误差项。同时,基于Lyaunov直接法保证了该闭环系统的控制误差项最终一致有界性。最后,仿真结果验证了所提出的控制器对移动目标和空间曲线的轨迹跟踪有效性。

摘要：Resistance analysis is an important analytical method used to evaluate the hydrodynamic performance of High Speed Craft (HSC). Analysis of multihull resistance in shallow water is essential to the performance evaluation of any type of HSC. Ships operating in shallow water experience increases in resistance because of changes in pressure distribution and wave pattern. In this paper, the shallow water performance of an HSC design concept, the semi-Small Waterplane Area Twin Hull (semi-SWATH) form, is studied. The hull is installed with fin stabilizers to reduce dynamic motion effects, and the resistance components of the hull, hull trim condition, and maximum wave amplitude around the hull are determined via calm water resistance tests in shallow water. These criteria are important in analyzing semi-SWATH resistance in shallow water and its relation to flow around hull. The fore fin angle is fixed to zero degrees, while the aft fin angle is varied to 0o, 5o, 10o, and 15o. For each configuration, investigations are conducted with depth Froude numbers (FrH) ranging from 0.65 to 1.2, and the resistance tests are performed in shallow water at the towing tank of UTM. Analysis results indicate that the resistance, wave pattern, and trim of the semi-SWATH hull form are affected by the fin angle. The resistance is amplified whereas the trim and sinkage are reduced as the fin angle increases. Increases in fin angle contribute to seakeeping and stability but affect the hull resistance of HSCs.

摘要：针对一类未配置推进器,仅依赖于舱体内的水泵和控制阀进行油体输送和浮力调节的水下自治漂流浮标系统,研制设计了定深控制技术方法。首先介绍了水下自治漂流浮标的浮力调节系统及其浮力调节原理,然后根据控制目标设计了关于深度跟踪误差和期望速度的特征函数曲线,进而基于试差法设计了水泵和控制阀的自动控制率,实现了浮标系统的定深控制。海上试验应用结果验证了所设计控制方法的有效性。