3D Porous Cu Current Collectors Derived by Hydrogen Bubble Dynamic Template for Enhanced Li Metal Anode Performance

Lithium (Li) metal is the most ideal anode material for high‐energy density batteries. However, the high activity of Li metal, the large volume change, and Li dendrite formation during cycling hinder its practical application. Herein, 3D porous Cu synthesized through a simple time‐saving hydrogen bubble dynamic template method is used as a host for the improved performance Li metal anode. Contrary to the planar Cu foil, the synthesized 3D porous structure can reduce the local current density, suppress the mossy/dendritic Li growth, and buffer the volume change in the Li metal anode. Highly stable Coulombic efficiency is achieved at different specific current densities (0.5, 1, and 2 mA cm^?2) with a capacity of 1.0 mAh cm^?2. Moreover, symmetrical Li|Li‐3D Cu cells show more stable cyclic performance with a lower overpotential even at a high current density of 3 mA cm^?2.     

水下接触爆炸下防雷舱舷侧空舱的内压载荷特性仿真研究

为研究水下接触爆炸下防雷舱舷侧空舱的内压载荷特性,在水下爆炸气泡第1次脉动周期的约3倍时间范围内,利用LS_DYNA软件对水下爆炸气泡与防雷舱舷侧空舱的相互作用过程和舷侧空舱的内压载荷特性进行了仿真分析,并通过模型试验对仿真结果及分析进行了验证。研究结果表明：伴随着水下爆炸气泡膨胀或收缩,爆炸产物气体从外板破口处流入或流出舷侧空舱,外板也相应地向里凹陷或向外凸出运动;舷侧空舱内部空间被外板花瓣隔成两个区域,舷侧空舱的内压载荷在花瓣前面和花瓣背面具有不同特性;采用有限元方法评估舷侧空舱外板的最大破坏程度时,可将计算时间取为气泡第1次脉动周期的5%.     

微孔阵列式绕回转体气泡减阻实验研究

为了研究回转体模型气泡减阻变化规律,深入了解通气两相流场的流动特性,采用高速摄像观察系统及测力系统相结合,进行了微孔阵列式绕回转体气泡减阻实验研究。结果表明：根据气泡沿下游发展过程中出现的不同流动形态,可将通气两相流场划分为3个区域：稳定区、脉动区、回流区;随着通气率的增加,稳定区及脉动区空泡份额增加,模型摩擦阻力持续减小,直至饱和通气率;回流区分离点向下游移动,尾部压力增加,至突变临界通气率处,回流区流动形态发生突变,流动介质由水气混合转变为气体为主,致使尾部压力出现突增,继而导致气泡减阻率出现突增。     

L形和Z形宽肢异形柱低周反复荷载试验研究

根据12根肢宽厚比分别为4∶1、5∶1和6∶1的宽肢L形和Z形截面柱在低周反复荷载作用下的试验研究,研究了肢宽厚比大小、箍筋配筋率对构件破坏形态以及极限荷载的影响,分析了以上因素对L形截面和Z形截面柱耗能能力和延性的不同影响,在分析试验结果的基础上提出了异形柱抗剪强度建议计算公式,最后给出了若干工程设计建议。     

舰船尾流散射特性的研究

利用Mie理论计算了单个气泡和舰船尾流横截面内气泡群的体散射函数.计算结果表明尾流中心的后向散射高于尾流边缘的.舰船尾流横截面内气泡群的散射与气泡大小,气泡尺寸分布和尾流深度有关系;在散射角180°附近后向散射增强显著;在散射角60°～80°之间,气泡群的散射相对于相邻角度有所增强.     

利用光学摄影术研究尾流气泡规律进展

舰船尾流中气泡对尾流特性的研究起着重要的作用.尾流中气泡的形状、大小以及数密度分布都是探测尾流的基础.用光学摄影方法研究尾流气泡具有直观、简便的特点.文章综述了自1979年以来各种研究气泡尾流的光学摄影方法,并对未来的研究重点提出了一些建议.     

计算两不同平行轴间距柱形电容器电容的保角变换法

介绍了保角变换法,利用保角变换中常用的对数变换和分式变换,分别计算了不同平行轴间距的柱形电容器的电容,并进行了讨论。结果表明,当两轴间距离平方等于内外圆柱半径平方之和的2倍时,电容器的电容与同轴电容器是等效的;当两轴间距分别为大于内外半径之和,或小于内外半径之差时,两种情况下,两轴间距的平方之和等于内外圆柱半径平方之和的2倍时,两种电容器的电容等效。     

液体温度对空泡生长和溃灭过程的影响

采用光偏转测试系统研究了不同温度纯净水中激光空泡脉动过程,通过实验获得了激光空泡在靶表面膨胀和收缩全过程,确定了空泡的最大、最小泡半径、脉动周期和泡壁运动速度。实验采用0℃到70℃的纯净水,测量了空泡的泡半径和脉动周期等特征参量变化情况。实验结果表明,液体温度是影响空泡脉动的一个非常重要的因素,随着液体温度的增加空泡的最大泡半径和溃灭周期均呈增加趋势。给出了相应的理论解释。     

高画质、低功耗的TFT LCD直接驱动方法

介绍了用于高画质、低功耗的ＴＦＴＬＣＤ的直接驱动方法,阐述了采用直接驱动方法的必要性及其对ＴＦＴＬＣＤ性能的改进。特别是对４种反转方式在图像质量和功耗方面的影响进行了比较。     

Magnetocontrollable Droplet and Bubble Manipulation on a Stable Amphibious Slippery Gel Surface

Smart manipulation of liquid/bubble transport has garnered widespread attention due to its potential applications in many fields. Designing a responsive surface has emerged as an effective strategy for achieving controllable transport of liquids/bubbles. However, it is still challenging to fabricate stable amphibious responsive surfaces that can be used for the smart manipulation of liquid in air and bubbles underwater. Here, amphibious slippery surfaces are fabricated using magnetically responsive soft poly(dimethylsiloxane) doped with iron powder and silicone oil. The slippery gel surface retains its magnetic responsiveness and demonstrates strong affinity for bubbles underwater but shows small and switching resistance forces with the water droplets in air and bubbles underwater, which is the key factor for achieving the controllable transport of liquids/bubbles. On the slippery gel surface, the sliding behaviors of water droplets and bubbles can be reversibly controlled by alternately applying/removing an external magnetic field. Notably, compared with slippery liquid‐infused porous surfaces, the slippery gel surface demonstrates outstanding stability, whether in air or underwater, even after 100 cycles of alternately applying/removing the magnetic field. This surface shows potential applications in gas/liquid microreactors, gas–liquid mixed fluid transportation, bubble/droplet manipulation, etc.