“推进一流本科教育,提高人才培养质量”的理念、路径与方法(笔谈)

建设世界一流大学需要高度重视本科教育。\"推进一流本科教育,提高人才培养质量\"的前提是要理解本科教育的本意,从不同维度反思\"我们需要什么样的本科教育\"\"什么是好的本科教育\"\"如何推进一流本科教育\"等问题。从宏观层面看,本科教育的使命是为了促进每一个大学生\"成才\"和\"成人\"。从现实需求看,一流本科教育不可忽视跨学科人才培养,需要按照学科标准、职业标准和学生标准对专业进行重新分类,为跨学科专业设置、新工科建设以及高校专业设置与调整开辟理论空间。目前,我国本科教育的最大问题是培养目标不明确,面临学术型与应用型的抉择。好的本科教育需要基于本科生\"关键能力\"的培养,彻底消除他们对于专业的陌生感,满足他们对于理智的好奇心,撤除横亘在大学与社会之间的藩篱并激发他们的创新创业精神。具体来说,一流本科教育是一流\"教\"与\"学\"的统一,需要一流的投入和一流的教育管理,需要在教学改革中侧重技术层面的突破。一流本科教育不是一流大学的\"专利\",不是\"一类本科\",没有固定模式,更不能盲目追求学术GDP。对于应用型本科高校而言,在\"一流本科教育\"中要结合学校特点和办学实际,做出异于\"双一流\"建设高校的现实抉择。作为一类特殊性质的高校,中外合作大学在建设一流本科教育的过程中,要在引入国外优质高等教育资源的基础上,强调对相关资源的消化、吸收、融合、创新,从而培养出符合社会主义现代化建设要求的高素质国际化人才。国家社会科学基金教育学一般项目“新时代中国特色高等教育话语体系构建研究”(BIA180200);;教育部国别和区域研究专项资金资助课题“高等学校专业设置规划与质量保障体系研究

Transition from tunneling leakage current to molecular tunneling in single-molecule junctions

数十年来，半导体工业一直遵循基于“摩尔定律”所设定的发展蓝图，逐步提升集成电路芯片上晶体管的集成度和运行速度，减小器件尺寸。为探索这一尺寸极限，课题组基于机械可控裂结技术自主开发了具有飞安级电学测量和亚纳米级位移控制灵敏度的科学仪器，在国际上首次获取了一系列具有不同重复单元的寡聚苯乙炔类分子电导随电极间距的演变关系，并发现随着电极间距的缩小，器件电输运由通过分子器件电流占主导逐步转变到由隧穿漏电流占主导。对于本研究中具有最小尺寸的寡聚苯乙炔分子器件，其由于隧穿漏电流所制约的尺寸极限可小至0.66 nm，预示了有机分子器件在未来电子器件小型化方面具有重要的应用潜力。 这一研究工作是在化学化工学院洪文晶教授、萨本栋微纳研究院杨扬助理教授以及英国Durham University的MartinR. Bryce教授共同指导下完成的。能源材料化学协同创新中心iChEM Fellow刘俊扬博士为论文第一作者，博士研究生郑珏婷、李瑞豪和硕士研究生黄晓艳、唐永翔、皮九婵、本科生王飞等参与了研究工作。田中群教授、毛秉伟教授和师佳副教授为论文工作提供了重要指导。【Abstract】The tunneling leakage current will be a major quantum obstacle during miniaturization in the semiconductor industry down to the scale of several nanometers. At this scale, to promote charge transport and overcome the tunneling leakage current between the source and drain terminals, molecular electronic junctions offer opportunities by inserting molecules between these two electrodes. Employing a series of oligo(aryleneethynylene) (OAE) molecules, here we investigate the transition from tunneling leakage current to molecular tunneling in the single-molecule devices using mechanically controllable break junction (MCBJ) technique, and the transition distances of the OAE molecular junctions were determined and even down to 0.66 nm for OAE2 molecular junction, which demonstrates that the intrinsic charge transport properties of a single-molecule device can be outstripped from the tunneling leakage current. Consequently, molecular electronic devices show the potential to push the ultimate limit of miniaturization to the scale of several angstroms.This work was supported by the National Key R&D Program of China (2017YFA0204902). This work was also generously supported by the Young Thousand Talent Project of China, the EC FP7 ITN “MOLESCO” project number 606728, the National Natural Science Foundation of China (nos. 21703188, 21673195, 21503179), and the China Postdoctoral Science Foundation (2017M622060). 该工作获得科技部国家重点研发计划课题（2017YFA0204902），国家自然科学基金委（21673195、21703188、21503179）以及中国博士后科学基金（2017M622060）等项目的资助，也得到了固体表面物理化学国家重点实验室、能源材料化学协同创新中心的支持

一种水下空腔噪声控制方法、装置及介质

本发明涉及了一种水下空腔噪声控制方法、装置及介质。一种水下空腔噪声控制方法,用于空腔噪声控制装置中,包括：设计多个分布在预设范围内的所述喷水机构位置的样本值；利用CFD开展流体动力学仿真计算得到计算结果,将计算结果、预设流动控制方程和预设涡流物理模型作为训练数据集；基于训练数据集对神经网络进行训练,得到用于快速预测的代理模型；根据所得代理模型获得在空腔几何尺寸和航行器航行速度下的预测结果；判断预测结果的噪声是否满足之前的设定值,若不满足,则用喷水机构的控制系统调节噪声。本发明提高降低水下航行器空腔噪声的灵活性和有效性

Experimental and numerical study on ventilated cavitation of high-speed projectile

In this study, ventilated cavitating flow characteristics around an axisymmetric projectile are investigated by combining experiments and numerical simulations. Experiments were carried out with a Split-Hopkinson pressure bar launch system and the pressure-equaling exhaust technology. Modular projectiles are designed to experimentally investigate the influence of head shape and ventilatory volume on flow characteristics. Large eddy simulation model is applied to obtain more flow field information. Compared with the conical head projectile, the hemispherical head projectile has a thinner attached cavity and more local detachment of the cavity. The statistical structure of the velocity and pressure fluctuations are analyzed by combining histograms and Q-Q diagrams. The results show that the pressure drag is dominant in the total drag and the periodic pulsation of the tail cavity and the stable vortex structure at the tail cause the variation of drag. The larger cavity volume changes the actual shape of the projectile, making the drag of the conical head projectile higher. The evolution characteristics of the cavitating flow field around the projectile with different ventilatory volumes are obtained, and the relationship between pressure fluctuation and chamber volume is derived. It is found that the reentrant jet causes a reverse flow at the nozzle, which leads to local pressure rise at the same interval. The above research work could contribute to the design and flow control of the ventilated cavity body

Experimental study on the mechanism of cavitation-induced ventilation

In this study, the cavitating flow and cavitation-induced ventilation flow around a surface-piercing hydrofoil were investigated to gain in-depth understanding of the interaction mechanism between the vaporous cavity and free surface at low cavitation numbers. Experiments were conducted in a constrained-launching water tank to visualize the cavity using a high-speed camera. Unsteady cloud cavitation and cavitation-induced ventilation at atmospheric pressure were observed and analyzed while piercing the free surface. The flow regime map was summarized at a fixed aspect ratio of AR(h) = 1.5. Subsequently, a physical model was proposed to predict the maximum depression depth of the water surface (H) at the trailing edge of the hydrofoil. Both the physical model and experimental results reveal that the non-dimensional depth H/c has a linear relation to Fn2 c x Re-c x sin(2)alpha. Finally, a criterion for cavitation-induced ventilation based on the improved lifting-line theory and a physical model were proposed. A new relation H/L-c similar to alpha(0.5) was obtained, where L-c is the maximum cavity length. The results of this study can guide the design and application of hydrofoils for ventilation and cavitation processes

一种用于高速水面航行器的水翼及设计方法

本发明公开了一种高速水面航行器的水翼及设计方法,前水翼和后水翼分别设有升力部件和支撑部件,升力部件的翼型形状相同,沿翼型的弦长方向,翼型的厚度先增大后减小；在翼展方向上,从翼展的一端到另一端,升力部件翼型的弦长先增大后减小,使得升力部件的前缘呈对称的弧形,同时翼型的最大厚度相同,形成具有光滑弧形的吸力面,以减小流动阻力；航行时,支撑部件始终处于切割自由面状态,升力部件完全浸没在水中且贴近自由面航行。本发明还提供了一种设计方法,通过参数化设计、替代模型和多目标优化算法,使得应用了该水翼的高速水面航行器,可大幅度提高升阻比与稳定性,解决了现有技术中高速水面航行器无法同时兼顾升力和航行稳定性的问题

Research on ventilation and supercavitation mechanism of high-speed surface-piercing hydrofoil

Flow structures and hydrodynamic performance of high-speed surface-piercing hydrofoils were studied by numerical simulation, with an emphasis on the interaction mechanism between supercavitation and natural ventilation. Compared with the available experimental data, the numerical method could predict the cavitation and ventilation well. The numerical simulation results show that the flow over hydrofoil with blunt trailing edge is more conducive to separating. The semi-ogive hydrofoil was used to explore the influence of angles of attack on ventilation and cavitation. The ventilation rate increases with the increase in the angles of attack. At small attack angles (alpha = 0 & DEG; and 2 & DEG;), the regional ventilated flow is found in supercavitation. The vortex street structures and twin vortices closure mode are formed in the closure region of the supercavity. At moderate attack angles (alpha = 6 & DEG; and 10 & DEG;), the thickness of the undisturbed liquid sheet (delta) becomes thinner and the natural supercavitation transits to fully ventilated supercavitation through the cavitation-induced ventilation, but the ventilation position is different because of Taylor instability. The hydrodynamic coefficients remain relatively stable in natural supercavitation and the lift coefficient reduce to half of the original value when the supercavitation is fully ventilated, which are caused by the pressure changes on the suction and pressure surfaces.& nbsp;& nbsp;(c)& nbsp;2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)