Modeling of multi-connected porous passageway for mould cooling

Cooling channel design in the plastic injection moulding process is of paramount importance to the performance of the mould, influencing the quality of the parts being produced and productivity of the process. However, cooling channel design is usually limited to relatively simple configurations as well as conventional machining processes, such as straight-line drilling, and milling, etc. The cooling performance may not meet the expectations of the mould engineers.This paper proposes an alternative design method for a conformal cooling passageway with multi-connected porous characteristics based on the duality principle. The proposed method can provide a more uniform cooling performance between the mould plate and the conformal cooling passageway than the existing conformal cooling channel design. Injection mould defects like warpage or hot spots can be avoided.In this study, a 3D mould plate model was offset negatively and the location of the proposed multi-connected porous cooling passageway was identified. The negatively offset model was decomposed into a finite number of cubical cells via the sub-boundary spatial enumerated cell decomposition. Then a duality relationship between the primal and the dual graphs was developed. This provided the preliminary layout of the multi-connected porous passageway for the coolant flow in multiple directions. The cooling channel axis design of the multi-connected porous passageway, illustrated by the skeleton from the dual graph, was created. Following a Boolean difference operation, the proposed multi-connected porous cooling passageway inside the mould plate was able to be generated and fabricated with the aid of rapid tooling technologies. A real-life case study for the design of a multi-connected porous cooling passageway was implemented and examined. The effects of coolant flow and cooling performances, analyzed by computational fluid dynamics simulation, were validated.     

应用于冷却系统的多孔介质电渗泵研究

对多孔介质电渗泵性能进行研究,分析电渗泵的流率和压力,为多孔介质电渗泵制作提供参考.依据电渗流控制方程,利用Debye-Huckel近似得到单根圆形管电渗流的近似解析模型,采用MEMS数值仿真软件CoventorWare对电渗泵模型进行求解分析,得到电渗泵流场的分布.基于电渗流的近似解析模型,采用截断高斯分布对多孔介质...     

HMI在四辊可逆铝箔轧机中的应用

本文介绍Φ2 1 0 /Φ5 0 0× 80 0mm四辊液压轧机厚度预控系统中采用人机界面实现参数在线调整 ,大大提高预控的控制精度 ,减少轧机产品的厚度误差 ,是厚度自动控制 (AGC)的一项创新。     

A facile strategy to integrate robust porous aluminum foil into microfluidic chip for sorting particles

High efficiency integration of functional microdevices into microchips is crucial for broad microfluidic applications. Here, a device-insertion and pressure sealing method was proposed to integrate robust porous aluminum foil into a microchannel for microchip functionalization which demonstrate the advantage of high efficient foil microfabrication and facile integration into the microfluidic chip. The porous aluminum foil with large area (10 × 10 mm²) was realized by one-step femtosecond laser perforating technique within few minutes and its pores size could be precisely controlled from 3 μm to millimeter scale by adjusting the laser pulse energy and pulse number. To verify the versatility and flexibility of this method, two kinds of different microchips were designed and fabricated. The vertical-sieve 3D microfluidic chip can separate silicon dioxide (SiO₂) microspheres of two different sizes (20 and 5 μm), whereas the complex stacking multilayered structures (sandwich-like) microfluidic chip can be used to sort three different kinds of SiO₂ particles (20, 10 and 5 μm) with ultrahigh separation efficiency of more than 92%. Furthermore, these robust filters can be reused via cleaning by backflow (mild clogging) or disassembling (heavy clogging).     

一种多变量系统辨识法及其在蒸发过程的应用

为有效分析分子蒸馏系统中的蒸发环节,提出了一种带有延迟环节的多变量系统参数辨识方法。采用将多变量系统辨识转化为多个单变量系统辨识的思想,对辨识问题进行简化,并给出了该思想的依据。依据阶跃激励信号下被辨识过程的响应数据建立关系式组,并应用辛普森（Simpson）积分公式得到了关系式组中未知系数,通过对该关系式组的求解最终获得蒸发系统的传递函数矩阵。仿真及实际过程中的应用表明,采用的辨识方法具有较强的可实践性及良好的辨识效果。     

微型可编程光栅光谱模拟特性及其应用研究

研究了基于MOEMS技术的微型可编程光栅的光学特性.对平行复色光正入射时微型可编程光栅的衍射场进行了理论分析,分析表明可以通过对可编程光栅编程状态的预先设定,使其衍射输出对应于不同目标物质的光谱,即模拟光谱.最后介绍了微型可编程光栅的光谱模拟特性在相关光谱检测法中的应用,分析了其相对于传统方法的优点.     

Coding coarse grained polymer model for LAMMPS and its application to polymer crystallization

We present a patch code for LAMMPS to implement a coarse grained (CG) model of poly(vinyl alcohol) (PVA). LAMMPS is a powerful molecular dynamics (MD) simulator developed at Sandia National Laboratories. Our patch code implements tabulated angular potential and Lennard-Jones-9-6 (LJ96) style interaction for PVA. Benefited from the excellent parallel efficiency of LAMMPS, our patch code is suitable for large-scale simulations.This CG-PVA code is used to study polymer crystallization, which is a long-standing unsolved problem in polymer physics. By using parallel computing, cooling and heating processes for long chains are simulated. The results show that chain-folded structures resembling the lamellae of polymer crystals are formed during the cooling process. The evolution of the static structure factor during the crystallization transition indicates that long-range density order appears before local crystalline packing. This is consistent with some experimental observations by small/wide angle X-ray scattering (SAXS/WAXS). During the heating process, it is found that the crystalline regions are still growing until they are fully melted, which can be confirmed by the evolution both of the static structure factor and average stem length formed by the chains. This two-stage behavior indicates that melting of polymer crystals is far from thermodynamic equilibrium. Our results concur with various experiments. It is the first time that such growth/reorganization behavior is clearly observed by MD simulations.Our code can be easily used to model other type of polymers by providing a file containing the tabulated angle potential data and a set of appropriate parameters.

Program summary

Program title: lammps-cgpvaCatalogue identifier: AEDE_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDE_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: GNU's GPLNo. of lines in distributed program, including test data, etc.: 940 798No. of bytes in distributed program, including test data, etc.: 12 536 245Distribution format: tar.gzProgramming language: C++/MPIComputer: Tested on Intel-x86 and AMD64 architectures. Should run on any architecture providing a C++ compilerOperating system: Tested under Linux. Any other OS with C++ compiler and MPI library should sufficeHas the code been vectorized or parallelized?: YesRAM: Depends on system size and how many CPUs are usedClassification: 7.7External routines: LAMMPS (http://lammps.sandia.gov/), FFTW (http://www.fftw.org/)Nature of problem: Implementing special tabular angle potentials and Lennard-Jones-9-6 style interactions of a coarse grained polymer model for LAMMPS code.Solution method: Cubic spline interpolation of input tabulated angle potential data.Restrictions: The code is based on a former version of LAMMPS.Unusual features.: Any special angular potential can be used if it can be tabulated.Running time: Seconds to weeks, depending on system size, speed of CPU and how many CPUs are used. The test run provided with the package takes about 5 minutes on 4 AMD's opteron (2.6 GHz) CPUs.References:

[1]

D. Reith, H. Meyer, F. Müller-Plathe, Macromolecules 34 (2001) 2335-2345.

[2]

H. Meyer, F. Müller-Plathe, J. Chem. Phys. 115 (2001) 7807.

[3]

H. Meyer, F. Müller-Plathe, Macromolecules 35 (2002) 1241-1252.

     

PLC在高炉净循环水系统的应用

介绍在高炉净循环水冷却系统中应用小型PLC所构成的控制系统,详细介绍了系统的构成、功能以及控制策略。     

PLC控制在内冷水水质监测系统中的应用

直流输电中内冷水循环系统的水质问题涉及到换流站的安全稳定、运行,是电力系统必须定期监测的项目。本文介绍了应用PLC控制一套换流站内冷水在线监测系统,利用OPC服务实现西门子S7-200型号的PLC与上位机之间的通讯,实时在线对内冷水水质状况进行监测,对水质变异提前进行预警。     

FFH100型自动蒸发设备比对分析及使用

为满足水文观测的自动化要求，给水文站自动蒸发设备的推广使用提供依据，通过在安塞水文站安装FFH100型自动蒸发设备，统计自动蒸发设备累积观测的与人工观测的日蒸发量数据（共计82组），在分析自动蒸发设备构造及计算原理的基础上，对82组日蒸发量数据进行比对分析，分析观测误差及来源。数据定量回归分析及自动蒸发设备使用结果表明：人工和自动蒸发设备观测得到的2个数据变量的相关系数Rp 达到0.988，具备很高的单值对应关系，符合常数要求，能够满足水面蒸发观测规范要求。且自动蒸发设备在降雨期间能对蒸发量进行计量并自动采集与远程发报，实现蒸发观测的自动无人化，可作为北方地区非冰期水面蒸发自动测量设备选择之一。     

Micro ultrasonic welding: joining of chemically inert polymer microparts for single material fluidic components and systems

This paper presents a novel powerful micro joining process—the ultrasonic welding of real micro polymer parts. It seems to be especially suited for the manufacturing of single material, chemically inert plastic microfluidic components and systems for applications in the field of pharmaceutics, biotechnology and life sciences as well as for high temperature polymer fluidic microdevices. The performance of this ‘micro ultrasonic welding’ process, alone using a pneumatic standard ultrasonic welding machine, is demonstrated by the example of covering and sealing microchannels and assembling a piezo-driven micropump.

     

Micro ultrasonic welding: joining of chemically inert polymer microparts for single material fluidic components and systems

This paper presents a novel powerful micro joining process—the ultrasonic welding of real micro polymer parts. It seems to be especially suited for the manufacturing of single material, chemically inert plastic microfluidic components and systems for applications in the field of pharmaceutics, biotechnology and life sciences as well as for high temperature polymer fluidic microdevices. The performance of this ‘micro ultrasonic welding’ process, alone using a pneumatic standard ultrasonic welding machine, is demonstrated by the example of covering and sealing microchannels and assembling a piezo-driven micropump.     

Planar microreactor for biochemical application made from silicon and polymer films

Recently the progress of life science has been increasing rapidly, and the importance of the microfluidics for DNA analysis systems has been widely recognized, especially in medical fields. The polymerase chain reaction (PCR) is an essential technique for DNA assay of various diseases and it has been a strong requirement to shorten the total of PCR cycles more and more. We developed the microreactor with a single cell for PCR using fabrication technologies of MEMS. The reactor body and cover were sealed using high thickness PDMS prototyping film without using adhesive in order to achieve repeat grabbing motion for direct sample injection, resumption and cleansing the reaction cell. Good reproducibility of the heat cycling was obtained. The heating rate and cooling rate during PCR was 6.8 and 2.7°C, respectively, which well corresponds to the design parameters. The homogenous temperature distribution of variance less than 2.0°C was obtained. It is demonstrated that amplification of the DNA was successfully achieved by using the microreactor.     

微气体传感器阵列及神经网络的应用

简要分析由MEMS工艺制成的新型微气体传感器阵列的原理及其优点 ,在此基础上 ,应用人工神经网络对气体传感器阵列的输出进行模式分类、识别 ,实现对单一或混合气体的有选择性探测 ,识别率可高达 95 %。     

黑液蒸发过程能量系统模拟及其节能优化应用

黑液蒸发浓缩过程是制浆造纸厂主要能耗工序之一,约占总能耗的24%～30%。为缩小我国黑液蒸发过程能耗与国际先进水平的差距,本文针对具体示例展开了节能降耗的研究分析。文中应用WinGEMS模拟软件,蒸汽效率、(?)分析为分析方法,以黑液蒸发工厂实际过程为案件,进行了蒸发过程节能优化前后的模拟研究。结果表明应用WinGEMS软件能方便准确地进行黑液蒸发过程的能量和物料流的模拟和优化设计;文内提出的蒸发过程节能优化方案,在保证安全生产的同时,蒸汽效率、(?)能利用率皆有提高,提高百分点分别为12%、14%,且新蒸汽用量比优化前降低了23%,出效黑液浓度比优化前提高了4.2%。示例的成功实施,对相关产业的节能项目提供重要的指导及借鉴意义。     

Cost-effective fabrication of ionic polymer based artificial muscles for catheter-guidewire maneuvering application

Microsystem Technologies - In this paper, we have designed and developed an ionic polymer metal composite (IPMC)-based artificial muscles by physical vapor deposition based fabrication technique....     

Evaluation of Si liquid cooling structure with microchannel and TSV for 3D application

The development of 3D integration has caused a major technology paradigm shift to all integrated circuit (IC) devices, interconnects, and packages. Despite the benefits of 3D integration, this process faces the key challenge of thermal management, especially for high power and high density IC devices. Due to the limitations of conventional thermal solutions, liquid cooling technology has become a field of great interest for IC thermal management. In this study, an on-chip liquid cooling module with three different through Si vias (TSVs) and a fixed microchannel structure has been fabricated on an Si wafer using deep reactive ion etching and anodic bonding, followed by a grinding and dicing process. Pressure drop, coolant flow, and temperature difference before and after liquid flow were experimentally measured. TSV depth and diameter have been shown to have little effect on the change of pressure drop; however, shallower TSV depth and larger TSV diameter led to improved liquid cooling performance. The trapezoidal TSV showed slightly more effective cooling than did the scalloped TSV or the straight TSV.

     

Canonical correlation analysis-based fault detection methods with application to alumina evaporation process

In this paper, canonical correlation analysis (CCA)-based fault detection methods are proposed for both static and dynamic processes. Different from the well-established process monitoring and fault diagnosis systems based on multivariate analysis techniques like principal component analysis and partial least squares, the core of the proposed methods is to build residual signals by means of the CCA technique for the fault detection purpose. The proposed methods are applied to an alumina evaporation process, and the achieved results show that both methods are applicable for fault detection, while the dynamic one delivers better detection performance.     

微加速度计中新型微杠杆机构设计和分析

设计谐振式微加速度计时,需要考虑一个最关键的问题是提高其灵敏度.放大质量块产生的惯性力是提高灵敏度的最有效方法.基于柔性铰链技术设计一种新型两级微杠杆放大机构,并建立了放大机构的力学和数学模型,在此基础上进行了解析法分析和参数优化设计;同时利用有限元分析方法对其进行了仿真计算.计算结果显示机构的放大倍数约为102倍.这一设计方案极大地提高了微加速度计的灵敏度.