为检测微弱周期信号对二次采样随机共振相关参数的研究

分析了二次采样随机共振中涉及到的重要参数采样频率和二次采样频率,结合理论推导与仿真,得出了这两个参数对系统输出效果的具体影响,同时分析了造成这些影响的原因,提出了这两个参数选取的方法,为更好地应用二次采样随机共振检测微弱周期信号提供了依据。     

Rapid growth of angle-confined large-domain graphene bicrystals

In the chemical vapor deposition growth of large-area graphene polycrystalline thin films,the coalescence of randomly oriented graphene domains results in a high density of uncertain grain boundaries (GBs).The structures and properties of various GBs are highly dependent on the misorientation angles between the graphene domains,which can significantly affect the performance of the graphene films and impede their industrial applications.Graphene bicrystals with a specific type of GB can be synthesized via the controllable growth of graphene domains with a predefined lattice orientation.Although the bicrystal has been widely investigated for traditional bulk materials,no successful synthesis strategy has been presented for growing two-dimensional graphene bicrystals.In this study, we demonstrate a simple approach for growing well-aligned large-domain graphene bicrystals with a confined tilt angle of 30° on a facilely recrystallized single-crystal Cu (100) substrate.Control of the density of the GBs with a misorientation angle of 30° was realized via the controllable rapid growth of subcentimeter graphene domains with the assistance of a cooperative catalytic surface-passivation treatment.The large-area production of graphene bicrystals consisting of the sole specific GBs with a tunable density provides a new material platform for fundamental studies and practical applications.     

Characterization and optimized electrochemical performances of LiFe(1-2x)ZrxPO4/C nanocomposites as cathode materials for lithium-ion batteries

A series of nanocomposite LiFe(1-2x)ZrxPO4/C (x = 0.01,0.02, 0.03, 0.04, 0.06) were prepared by carbon thermal reduction method. With this strategy, the Li3PO4 impurity phase can be obviously reduced in the Zr-doped samples and the electrochemical performance is obviously improved by Zr doping compared with the undoped one. The best electrochemical performances were observed in LiFe(0.92)Zr(0.04)PO4/C as well as good cycle stability.     

传递函数法在非局部弹性梁动力学分析中的应用

采用传递函数方法进行了非局部弹性梁的动力学分析。非局部弹性梁内一点的应力与梁某一区域内任意一点的应变均有关系。本文基于Eringen的非局部弹性积分型本构关系,采用幂指数型核函数,利用Laplace变换导出梁的四阶偏微分形式振动方程,通过定义状态向量,将控制方程化为一阶微分方程组,并采用传递函数方法进行了求解,针对两种边界条件给出了非局部弹性梁的固有频率和固有振型。结果表明,同阶频率下,非局部弹性梁的频率比局部梁的频率低,振型基本一致。     

Microfluidic Mass Production of Stabilized and Stealthy Liquid Metal Nanoparticles

Functional nanoparticles comprised of liquid metals, such as eutectic gallium indium (EGaIn) and Galinstan, present exciting opportunities in the fields of flexible electronics, sensors, catalysts, and drug delivery systems. Methods used currently for producing liquid metal nanoparticles have significant disadvantages as they rely on both bulky and expensive high‐power sonication probe systems, and also generally require the use of small molecules bearing thiol groups to stabilize the nanoparticles. Herein, an innovative microfluidics‐enabled platform is described as an inexpensive, easily accessible method for the on‐chip mass production of EGaIn nanoparticles with tunable size distributions in an aqueous medium. A novel nanoparticle‐stabilization approach is reported using brushed polyethylene glycol chains with trithiocarbonate end‐groups negating the requirements for thiol additives while imparting a “stealth” surface layer. Furthermore, a surface modification of the nanoparticles is demonstrated using galvanic replacement and conjugation with antibodies. It is envisioned that the demonstrated microfluidic technique can be used as an economic and versatile platform for the rapid production of liquid metal‐based nanoparticles for a range of biomedical applications.     

预付费用户实现短消息业务的关键技术分析

介绍了目前国内移动智能网系统和短消息系统的现状 ,在此基础上提出了基于移动智能网的预付费用户实现短消息业务的 3种解决方案 ,对各方案进行了分析和比较。最后 ,介绍了CMIN0 2移动智能网系统中预付费短消息业务的实现。     

Fe-C-N合金板条马氏体的组织构成

采用适射电子显微镜对五种Fc—C—N合金的板条马氏体的束内和束界区进行详细的观察和分析。研究发现板条马氏体组织中存在填塞马氏体。板条马氏体组织是由一簇簇平行排列的大小板条,以及填充在马氏体板条间,束界和界隅内的不定外形的填塞马氏体和条间残余奥氏体薄膜或膜片所构成。     

Sn及其氧化物超微粉的制备与测试

本文采用气体蒸发法制备出粒度不到５ｎｍ的Ｓｎ及其氧化物的超微粉。利用热重，差热分析和Ｘ射线衍射谱等测试方法研究了热处理制度对其粒度，成份和气敏特性的影响，发现了ＳｎＯ_２正交相的存在。