Atomic-scale simulations for lithium dendrite growth driven by strain gradient

Dendrite formation is a major obstacle, e.g., capacity loss and short circuit, to the next-generation high-energy-density lithium (Li)-metal batteries. The development of successful Li dendrite mitigation strategies is impeded by an insufficient understanding in Li dendrite growth mechanisms. The Li-plating-induced internal stress in Li-metal and its effects on dendrite growth have been widely studied, but the underlying microcosmic mechanism is elusive. In the present study, the role of the plating-induced stress in dendrite formation is analyzed through first-principles calculations and ab initio molecular dynamic (AIMD) simulations. It is shown that the deposited Li forms a stable atomic nanofilm structure on the copper (Cu) substrate, and the adsorption energy of Li atoms increases from the Li-Cu interface to the deposited Li surface, leading to more aggregated Li atoms at the interface. Compared with the pristine Li-metal, the deposited Li in the early stage becomes compacted and suffers the in-plane compressive stress. Interestingly, there is a giant strain gradient distribution from the Li-Cu interface to the deposited Li surface, making the deposited atoms adjacent to the Cu surface tend to press upwards with perturbation and causing the dendrite growth. This provides an insight into the atomicscale origin of Li dendrite growth, and may be useful for suppressing the Li dendrite in Li-metal-based rechargeable batteries.     

新型4-羟色胺类化合物的合成及生物活性

以4-羟基吲哚为原料,经吲哚环4位乙酰基化、3位亲电取代、酰胺化和还原加氢等反应合成目标化合物7.通过核磁共振氢谱及碳谱对化合物进行结构表征,并对目标化合物进行体外抗氧化生物活性测试.初步生物活性测试结果表明,化合物7a,7b,7c和7d对DPPH·均有很强的清除作用(清除率为85.25%~90.73%),7e,7f,7g,7h作用较差;目标化合物与Vc相比,对·OH的清除作用稍差,最高清除率25.66%(Vc的最高清除率为34.67),但各化合物整体水平相当;在清除O-2·能力上化合物7a,7d,7g,7h最大清除率(分别为19.34,35.35,27.93和31.74)均强于同等浓度的Vc(17.58).     

Optic Fiber Interferometer for Absolute Distance Measurement

1.IntroductionAbsolutedistancemeasurementisfarfromanewtopic.However,itisstillafieldstimulatinggreatinterestsnowadaysduetoitSimportantroleinmanufacturingandassembly['J.SincethegreatsuccessachievedbyMichelsonandBenoitwhentheyfirstdevelopedaninterferometertodeterminethestandardmeterintermsofthemonochromaticredcadmiumline,theopticinterferometerhasbeenprovedtobeoneofthemostpreciseandefficientwayindisplacementmeasurementbecauseofitshighdiscriminationandsimplestructure.However,thetraditionalinterfe…     

Infinitely Many Sign-changing Solutions for a Schr(o)dinger Equation in RN

We consider the existence of infinitely many sign-changing solutions for the nonlinear timeindependent schr(o)dinger equations of the form {-△u+Vλ(x)u=f(u), u∈H1(RN), (1.1) where Vλ(x) = λα(x) + 1.     

幅相一致行波管高频电路CAD研究

 在行波管的设计和装配过程中，各部件的尺寸必须严格控制，高频电路参数的离散对行波管色散特性有极大的影响。使用螺旋导电面模型，模拟计算了高频结构各主要参数离散对色散特性和轴向互作用耦合阻抗的影响。分析计算了夹持杆宽度、翼片高度、螺旋线平均半径、螺距、夹持杆介电常数等离散时对色散特性和轴向互作用耦合阻抗的影响，为新型幅相一致行波管的设计和生产提供了很有价值的参考建议。     

锐钛矿二氧化钛超细纳米晶的三声子互作用

本文通过对粒径为2.2-25.5nm的锐钛矿二氧化钛超细纳米晶在83-293 K温度范围内的变温拉曼光谱的研究,得到了三声子互作用对拉曼频率和线宽的贡献随粒径的变化关系。结果表明锐钛矿二氧化钛超细纳米晶的三声子相互作用随粒径减小而加强。     

半导体激光自混频干涉式传感器中的干涉与调制

应用F-P模型，阐述了半导体激光自混频干涉式传感器的干涉与调制过程，同时给出了相应的计算．     

Internet中的物理资源

对Internet中的物理资源进行了较系统的介绍，主要内容有：综合物理网站、物理期刊网站和物理教学网站，其中重点介绍了美国和欧洲主要国家的物理网站和物理期刊网站，利用这些物理站点，可以方便的进行文献检索、物理会议查询，物理教学相关资料的查询和世界各大学物理系的查询；可以方便快捷的了解当今世界各国的物理教学学科研的最新进展，文中对各个物理站点的使用方法都一一做了详细的介绍，以方便读者使用。     

衍/折射光学元件消二级光谱的设计

 采用衍/折射光学元件结合的方法，使用两种玻璃设计了星载用长焦距望远物镜，对其二级光谱进行了校正。具体介绍了衍/折透镜望远透镜消二级光谱方法、步骤。计算机模拟结果表明：校正后的望远物镜轴上位置色差小于0.08mm，满足使用要求，并且设计方法步骤简单。     

具有避难所的非自治竞争系统的持续生存和全局稳定性

考虑一个四缀块模型，其中一缀块里有三个竞争种群，另外三个分别是它们的避难所，并且种群能在竞争缀块和各自的避难所间相互扩散．在一定的条件下，我们给出了此模型的持续生存，周期性和全局稳定性．