Numerical simulation of the wire‐pinning process in PET film casting: Steady‐state results

Poly(ethylene terephthalate) (PET) film casting involves melt flow through a slot die, across a small span, and onto a fast moving quench drum. In the “wire‐pinning” casting process, a thin electrified wire close to the line of contact with the drum creates a strong pinning force that delays air entrainment to higher line speeds. Nonuniform wetting of the die lips by the extruded melt is thought to be responsible for the formation of streaks, a defect in the machine direction. A finite element model of the film casting process with wire pinning was developed to assist in understanding what causes significant wetting of the lips and whether this can be avoided by electrostatic pinning. The solution of the governing equations provide the location of the static and dynamic contact lines, thus finding the wetting and pinning points in the process. The simulations investigate the sensitivity of the static wetting line locations on the die lands to the imposed values of static contact angle and die‐lip gap. It was found that while the contact angle has a small effect on the extent of die‐lip wetting within the parameter ranges examined, there is a considerable chance that the feed slot surfaces can be dewetted. This seems to be the greatest danger for causing streaks rather than excessive wetting of the die lands. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

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。     

A course on thin‐film transistor circuit design for modern displays

A new subject‐specific course on thin‐film transistor (TFT) circuit design is introduced, covering related knowledge of display technologies, TFT device physics, processing, characterization, modeling and circuit design. A design project is required for students to deepen the understanding even more and get hands‐on design experience. This course can be an intense 1‐week course to offer a full training of design engineers in an organized way to meet the ever‐increasing needs in display industry for TFT circuit design specialists. It can also be organized in one semester for electrical engineering Master's and Ph.D. students.     

Method for measuring thermal contact resistance of graphite thin film materials

Thermal contact resistance (TCR) is an important parameter in thermal analysis of materials. Because of many influential factors, it is difficult to find a general model or computational formula to calculate the TCR of a solid interface. In many engineering applications, TCR values are usually obtained through experiments. Unlike extensive research focusing on ordinary columnar materials, this paper aims at measuring the TCR values of graphite thin film materials. The technical challenge is that it is not convenient to embed thermocouples into such materials. To overcome this challenge, a steady-state method using a copper heat flux meter is developed, which provides a useful tool for indirect TCR measurement. In our experiments, the TCR values of the graphite thin film materials are successfully measured under different temperature and pressure levels. The results provide a valuable guideline for the use of this type of material in high-temperature, high-pressure applications.     

矿井EPON生存性与冗余可靠性研究

针对现有矿井通信网络在可靠性设计方面考虑不足、网络系统容灾能力较弱问题,分析了网络链路冗余度对矿井网络可靠性的影响,建立了矿井以太无源光网络(EPON)的网络生存性模型,并在此基础上提出了矿井EPON的树形、总线形和环形网络冗余结构,进而推导出上述结构的网络生存性计算方程。实验结果表明,矿井EPON的网络生存性与灾害强度、覆盖范围和网络结构有关,灾害强度和覆盖范围越大,网络生存性越小。在相同灾害强度和网络覆盖范围条件下,冗余结构网络的可靠性优于无冗余网络,双总线形冗余结构的生存性最高,双环形冗余结构的生存性次之,树形冗余结构的生存性最差。这对数字化矿井通信网络的可靠性预测和性能评估提供了理论依据。     

一种具有微纳孔隙结构的二氧化钛多孔膜层光催化系统

采用溶胶-凝胶法配合以离子注入的方式,研制了一种具有纳米和亚微米(零点几个微米)孔隙结构的锐钛矿相二氧化钛光催化膜。首先通过常规的溶胶-凝胶法制得密实的二氧化钛膜层,然后采用具有一定动能的Fe离子轰击膜层,从而在膜层中形成大量的微纳孔隙。这些微纳孔隙明显提高了原膜层的比表面积。光催化降解甲基橙溶液的实验结果表明,无论是在紫外光下还是在可见光下,所得多孔膜层的光催化效果均优于未造孔的二氧化钛膜层。     

Effect of Ni7+ Ion Irradiation on Structure and Ammonia Sensing Properties of Thermally Oxidized Zinc and Indium Films

ZnO and In2O3 films were prepared by thermal oxidation of vacuum deposited zinc and indium films, respectively onto the glass substrate at 30 C. The fabricated films have been irradiated with 100-MeV Ni7+ ions at different fluences ranging from 5×1011 to 5×1013 ions/cm2. The structural and gas sensing properties of pristine and irradiated films have been discussed. X-ray diffraction (XRD) pattern of pristine and irradiated films reveal that the films are polycrystalline in nature and crystallinity increases after irradiation. In this study, highly porous In2O3 nanorods evolved when being irradiated at a fluence of 5×1013 ions/cm2 while ZnO film shows decrease in number of nanowires. The ammonia sensing performance of the Ni7+ irradiated In2O3 films shows an improvement as compared to its pristine counterpart.     

Experimental investigation on flow improvement in compressor cascades

There is no general rule in the literature to help choose a correct flow control device for any given case of turbomachinery applications. This suggests individual optimization of flow control devices for each specific case. The objective of this study is to prove experimentally the benefits of passive control methods in improving the compressor performance. This allows to reduce the fuel consumption, leading to energy saving and reduction of atmospheric pollution. Two features have been controlled in this study: flow separation over the blade surfaces and the secondary flow over the cascade endwalls. Vortex generator ribs are tested on the blade suction side for flow reattachment on the blade surfaces, and low‐profile vortex generators are tested on the side walls of the compressor cascade against secondary flow losses. Different vortex generator designs are compared for total pressure recovery, flow turning, boundary layer characteristics, and pressure distributions over the endwalls. Copyright © 2016 John Wiley & Sons, Ltd.     

Tunable dual-wavelength ring fiber laser with stable output based on saturable absorber and thin core passive fiber

A dual-wavelength erbium-doped ring fiber laser is proposed and experimentally demonstrated though a detailed theoretical analysis and experimental verification. The proposed dual-wavelength erbium-doped fiber (EDF) laser, which is based on a ring fiber laser structure, is fabricated using two fiber Bragg gratings. By adjusting the gains and losses of the fiber laser structure, the laser can be switched between single- and double-wavelength modes. A saturable absorber (SA) is used to improve the output laser stability, which is further enhanced by splicing a thin core passive fiber (TCPF) into the laser cavity to produce a Mach–Zehnder filter effect. Optimizing the lengths of the SA and TCPF results in the adoption of a 1-m EDF and a 4-m passive fiber. On the basis of these enhancements and optimizations, a fiber laser with stable output is constructed that incurs single- or dual-wavelength laser shifts of less than 3 pm at room temperature over a period of 250 s.