Sub‐5 nm Dendrimer Directed Self‐Assembly with Large‐Area Uniform Alignment by Graphoepitaxy

Directed self‐assembly (DSA) using soft materials is an important method for producing periodic nanostructures because it is a simple, cost‐effective process for fabricating high‐resolution patterns. Most of the previously reported DSA methods exploit the self‐assembly of block copolymers, which generates a wide range of nanostructures. In this study, cylinders obtained from supramolecular dendrimer films with a high resolution (<5 nm) exhibit planar ordering over a macroscopic area via guiding topographical templates with a high aspect ratio (>10) and high spatial resolution (≈20 nm) of guiding line patterns. Theoretical and experimental studies reveal that this property is related to geometrical anchoring on the meniscus region and physical surface anchoring on the sidewall. Furthermore, this DSA of dendrimer cylinders is demonstrated by the non‐regular geometry of the patterned template. The macroscopic planar alignment of the dendrimer nanostructure reveals an extremely small feature size (≈4.7 nm) on the wafer scale (>16 cm²). This study is expected to open avenues for the production of a large family of supramolecular dendrimers with different phases and feature dimensions oriented by the DSA approach.     

发动机配气凸轮轮廓曲线设计与研究

配气凸轮作为配气系统的核心零部件,其轮廓曲线的设计是整个配气机构设计的关键。通过对Solid Works软件进行二次开发,得出一种配气凸轮轮廓曲线的参数化设计方法。此方法能够满足精度要求较高的凸轮轮廓曲线设计,为发动机配气凸轮轮廓线的设计提供了一种依据。     

泛亚C14发动机配气机构单阀系动力学分析

利用TYCON软件分别分析评价了C14配气机构中凸轮与平面挺柱之间的动力学关系、气阀落座情况、气阀弹簧各有效圈动力特性等。     

台达20PM运动控制器在包装膜打孔机上的应用

台达20PM运动控制器及伺服驱动系统已被应用于食品包装膜打孔机。应用实例表明，采用基于非周期凸轮控制模式和CAMTABLE表的高速交流伺服驱动来代替快速气缸打孔是一种极佳的解决方案。该文简介了该打孔机控制系统的构成，着重分析了追剪和高速比较与捕捉功能这两个控制要素和部分应用程序。     

Dislocation slip and twinning in Ni-based L12 type alloys

We report theoretical results on dislocation slip and twinning in Ni₃ (Al, Ti, Ta, Hf) compositions with L1₂ crystal structures utilizing first-principles simulations. The lattice parameters of Ni₃Al, Ni₃Al_0.75Ta_0.25, Ni₃Al_0.5Ta_0.5, Ni₃Ta, Ni₃Ti and Ni₃Al_0.75Hf_0.25 are calculated, and the crystal structures with lower structural energies are determined. We established the Generalized Stacking Fault Energy (GSFE) and Generalized Planar Fault Energy (GPFE), and calculated stacking fault energies APB (anti-phase boundary) and CSF (complex stacking fault) matched other calculations and experiments. Based on the extended Peierls–Nabarro model for slip and the proposed twin nucleation model, we predict slip and twinning stress and the results show a general agreement with available experimental data. The results show that in the studied intermetallic alloys, twinning stress is lower than slip stress; Ta and Hf ternary addition are substantial to increase flow stress in Ni₃Al. The models proposed in the paper provide quantitative understanding and guidelines for selecting optimal precipitate chemistry and composition to obtain higher mechanical strength in Shape Memory Alloys.     

Design and fabrication of a planar patch-clamp substrate using a silicon-on-insulator wafer

noise.     

平面转弯带式输送机技术方案浅析

主要介绍平面转弯带式输送机技术方案的设计计算及实现平面转弯的技术要点,保证托辊具有一定的安装支撑角,构成内曲线抬高角,增大成槽角,对线路进行合理设计,使普通带式输送机实现了平面转弯运行,并确定转弯半径和驱动功率,又用类比法对驱动装置进行了选型。具有良好的推广应用前景。     

Effects of combustor size and filling condition on stability limits of premixed H2‐air flames in planar microcombustors

An experimental study on stability limits of premixed hydrogen‐air flames in planar microcombustors (H = 1 mm and 1.5 mm) partially filled with porous medium is carried out, focusing on the effects of combustor sizes and filling conditions. Critical conditions for blow‐off, flashback, and breaking through the porous medium are experimentally measured. The blow‐off limits are nearly independent of combustor sizes and filling conditions, while the flashback limits are strongly influenced by the combustor size and the filling conditions. Critical values for breaking through are identified with two different methods, and it is shown that standing combustion waves are settled over a range of velocities, instead of a fixed value of filtration velocity, which is considered an important characteristic of microcombustion. Most results can be explained by the classic boundary velocity gradient theory by von Elbe and Lewis, and thus the validity of the theory to the present channel spacings is confirmed. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2571–2580, 2015     

带电子聚焦的氧化锌场发射背光源

液晶显示需要低功耗、均匀度好的光源作为背光源。为了降低功耗,提高显示图像质量,未来的液晶显示需要实现对背光源进行时间与阵列调制。对比现有的液晶显示用背光源,研究制备了氧化锌场发射光源。该光源采用氧化锌纳米针作为场发射阴极,采用平面栅极作为门电极调制结构实现亮度的连续可调,通过带有氧化镁二次电子发射层的金属栅网对电子进行聚焦实现光源的均匀照度。实验结果表明,带电子聚焦的氧化锌场发射光源具有较低的开启场强(1.1V/μm),较小的电压调制区间(小于150V),较高的发光强度(大于1 000cd/m2),且基于电子聚焦结构的设计,实现了光源的均匀稳定照度,可以提高液晶显示的图像质量。带电子聚焦结构的氧化锌场发射光源,既可实现对发光的时间与阵列调制,同时能提高发光的均匀性,将可作为液晶显示的理想背光源。