Particle deposition mechanisms during processing of advanced composite materials

Liquid composite moulding of advanced composite materials often comprises infiltration of a particle-filled resin into a multi-scale porous fabric. These injections/infusions are subject to severe particle depositions inside the reinforcement, leading to undesired inhomogeneous mechanical and functional properties. Hence, the mechanisms for particle depositions are investigated by detailed meso-scale experiments, analysed by microscopic imaging and micro-particle image velocimetry, and macroscopic infusions of a biaxial non-crimp fabric. It is shown that two main particle deposition mechanisms are filtration during fibre bundle impregnation and filtration induced by stationary flow through fibre bundles. It is also clarified where in the reinforcement the particles will deposit. Finally, a number of suggestions on how to process advanced composite materials with a more homogeneous particle distribution are launched.     

Packaging aspects of high-pressure food processing technology

High-pressure (HP) technology is a novel, non-thermal food preservation and processing technology whereby food is subjected to high isostatic pressure (100–600 MPa) at or around room temperature. This paper discusses the compatibility of HP technology with existing food packages, packaging materials and closures. Based on literature data and our own research data it is shown that:

• (i) Container-lid combinations, which have sufficient flexibility to compensate the limited compression of the food and the complete compression of air at these high pressures, can be HP treated without physical damage;
• (ii) Mechanical properties and barrier properties of multilayer plastic and aluminium foil packaging materials are not affected;
• (iii) HP does not influence migration
• (iv) Heat-seal strength and integrity also are not affected

It is concluded that packaged foods can be HP treated and that HP opens up new possibilities to make plastic packaging less expensive and more environmentally friendly.     

Plasma ash processing solutions for advanced interconnect technology

A mechanism for the modification of porous ultra low-k (ULK) and extreme ultra low-k (EULK) SiCOH-based materials is proposed. This is achieved by correlating film damage on a patterned structure measured by angular resolved x-ray photoelectron spectroscopy (ARXPS) with corresponding changes in reactive species radical density and ion current in the plasma measured by optical emission spectroscopy (OES), rare gas actinometry, and modeling. Line-to-line electrical leakage and capacitance data of nested line structures exposed to downstream ash plasmas suggest that other etching steps during back-end-of-the-line (BEOL) dual damascene processing are also critical for the overall modification induced to these materials.     

相邻采空区的协同处理技术分析

为了保证大宝山矿由地下开采改为露天开采模式后的施工安全和提高生产效率,采用三维激光扫描技术对大宝山37线664采空区及39线655采空区进行了探测,发现2个采空区空间位置较为接近,整体标高不相同,在空间位置上呈现相错状态。经钻孔勘探两采空区主要以硅化岩与矽卡岩为主,局部含有铜硫矿体,岩体条件较好,并确定了相应的采空区形态、分布范围等。为此,利用矿方多年治理采空区得出的经验公式进行预测,对2个采空区进行顶板稳定性分析。提出了联合使用强制爆破崩落与废石充填的方法 ,给出了爆破参数设计及施工要点。现场实施结果表明,相邻采空区被较好地充填,成功消除了对生产安全的威胁。     

复合材料机翼整体成型技术研究

对给定外型与尺寸的整体成型复合材料机翼进行了设计、 制备及力学性能实验研究。采用有限元分析软件, 对空心复合材料机翼进行静力学分析, 得到了承载效率与机翼几何尺寸的关系, 并确定了最优结构尺寸与复合材料纤维铺层厚度。采用石蜡芯模辅助气囊法成型技术, 制备了整体成型复合材料机翼, 并进行了三点弯曲实验测定, 分析了其破坏机制。三点弯曲实验研究发现, 整体成型复合材料机翼的破坏模式为上蒙皮的局部屈曲失效, 屈曲后仍有一定的承载能力。      

激光冲击强化技术原理及研究发展

激光冲击强化技术(LSP)是一种新型的激光应用表面处理技术。与传统表面改性技术相比,激光冲击强化技术能给材料带来更深的残余应力层,使材料表层晶粒细化甚至出现纳米晶,同时大幅提高材料的疲劳寿命。利用高能激光辐照约束层材料(黑漆、黑胶带或铝箔),约束层材料在瞬间熔融气化并产生高温高压的等离子体。等离子体冲击波是一种爆轰波,可以通过C-J模型计算冲击波的峰值压力。等离子体冲击波在约束层(水、光学玻璃)的约束下向材料内部传播,其压力远远超过了材料的弹性屈服极限,材料经历了弹性-塑性变形,最终材料表面形成稳定的残余应力场并发生微弱的塑性变形。本文介绍了激光冲击强化技术的研究发展历程,在此基础上对该技术发展方向进行了展望。

     

激光技术在塑料薄膜加工中的应用

塑料薄膜的激光切割和打孔看似微不足道,但将该工艺引入到制袋工艺中,制袋质量和包装功能将能进一步优化,企业的市场竞争力将进一步提升.介绍了激光技术应用于塑料薄膜的切割和打孔的原理和优势,回顾了激光技术在薄膜加工中的研究进展,并展望了激光技术在软包装应用中的广阔前景.     

图像处理技术在板料激光弯曲中的应用

为了提高激光弯曲过程数值模拟结果的验证精度,用图像处理技术对铝合金板料AA6056进行了激光弯曲变形过程的实时测量.自行设计了硬件测量系统和软件的测试系统,使用MV21300UM CCD拍摄板料上测量点在激光照射过程中的动态变化过程,通过软件测试系统中实时采集软件记录动态变化过程、图像处理软件进行图像处理,得到了测量点动态变化的实测曲线.实测曲线表明,板料厚度对激光弯曲过程的位移变化影响较大,板料越薄,边界效应越明显,使得位移的变化曲线越易出现突变.实验结果证明该实测方案是可靠有效的.     

Overhauser磁力仪低噪声信号处理技术

针对磁力仪输出信号信噪比低的问题,同时为给Overhauser磁力仪的研制提供参考依据,提出一种低噪声信号处理技术。首先根据质子旋进信号(FID)特点,建立系统噪声模型,分析探头电阻热噪声和放大器等效输入噪声对测量造成的影响,提出LC谐振方案和低噪声放大电路以提高系统信噪比并通过实验测试仪器噪声水平。最后,将所研制的磁力仪与商用磁力仪进行对比测试,实验表明:提出的信号处理技术能有效降低系统噪声,FID信号信噪比36 d B,研制的Overhauser磁力仪磁场测量精度0.2 n T,性能接近商用仪器水平,证明其在磁场测量中的有效性。     

Investigation of high ferriferous sulphide lead concentrates processing technology

This article is dedicated to the investigations of the individual complex processing of the high ferriferrous sulphide lead concentrates by the way of lead blast furnace reducing melting. The data of the trials series of high ferriferrous lead sinters' reduction melting with the operating blast furnace have been presented. The results of investigations indicate that low lead losses with the slag (1.4÷1.8 wt.‐%) can be achieved by maintaining a slag composition of 38.4÷41.1 wt.‐% FeO and 0.70÷0.74 CaO/SiO₂ ratio, with a lead sinter throughput – 55÷60 tonnes/m² · day. The slag liquidus temperature is estimated to be ?1170°C.     

用于声呐图像处理的侧抑制模型改进算法

以声呐图像边缘增强为背景,将侧抑制理论引入声呐图像处理中来。展开了侧抑制模型算法分析及优化研究,探索侧抑制算法模型的改进算法,仿真和实际声呐图像处理效果显示,改进算法处理图像边缘更加清晰,噪声抑制更加明显,可以提高图像声呐目标轮廓提取以及分类识别的准确率。     

盐雾试验对镁合金表面工艺处理技术影响的探讨

盐雾试验是一种主要利用盐雾试验设备所创造的人工模拟盐雾环境条件来考核产品或金属材料耐腐蚀性能的环境试验。盐雾试验的目的是为了考核产品或金属材料的耐盐雾腐蚀性能,而盐雾试验结果的判定正确与否是衡量产品或金属抗盐雾腐蚀性能好坏的关键。该文概述了镁合金经化学氧化等表面工艺处理后,经人工模拟盐雾试验揭示出由处理工艺引起的环境适应性问题,证明了盐雾试验的重要性,并提出了相应的改进方法。     

聚焦离子束技术及其在微纳加工技术中的应用

聚焦离子束（FIB）技术是一种集形貌观测、定位制样、成份分析、薄膜淀积和无掩模刻蚀各过程于一身的新型微纳加工技术。它突破了只能对表层成像和分析的局限，可以对样品进行三维的、表面下的观察和分析，也可以对样品材料进行切割研磨和沉积特定材料，用它可以获得以前无法得到的样品信息。从而为研究人员和制造人员提供了一种对多种样品在纳米尺度进行修改、制作和分析的有效工具。     

塑料加工成型技术的最新研究进展

依据塑料工业发展低耗、高效、环保型“绿色”加工成型技术的重大需求,随着塑料塑化输运方法的不断演变与创新,在塑料动态加工成型方法和设备的基础上提出和研究了基于拉伸流变的塑料加工成型方法和技术,着重讨论了拉伸形变支配的叶片挤压系统中塑料塑化输运过程、叶片挤压系统的技术特征和叶片塑化输运技术的应用。研究结果表明,与传统技术及设备相比较,这种新技术及设备具有加工历程缩短50 %以上、加工能耗降低30 %左右、混合混炼效果好、制品质量提高、对物料适应性广等优异的技术性能。同时发现,新技术及设备在多相多组份复合材料、剪切热敏感高分子材料等物料体系的加工方面具有独特优势。     

膜分离技术在山楂加工中的应用

用超滤将９９％以上的果胶从山楂浸提液中分离出来，并使果胶浓缩至３０ｇ／Ｌ以上，然后通过喷雾干燥得到果胶粉。该粉的胶凝度大于１８０，其得率是鲜果质量的３％左右，脱果胶的山楂汁经反渗透浓缩至可溶固形物２０°Ｂｘ，其得率是鲜果质量的４０％左右。实验中重点考察了压力、温度、料液流速及洗滤等操作条件对膜通量和分离的影响。该技术已在工业生产中得到应用。     

Surface light scattering: integrated technology and signal processing

The miniaturization of surface-scattering instruments for measuring viscoelastic properties is investigated. The concepts are based on the use of holographic optical elements and integrated optics. Compact forms of optics that provide the necessary spatial and angular selections are devised. Four systems representing increasing levels of integration are considered. It is demonstrated that efficient signal and data processing can be achieved by evaluation of the statistics of the derivative of the instantaneous phase of the detector signal.     

Greencast-process, a new ceramic technology for plastics processing

The Greencast process is a new lost-core technology for the production of hollow parts from thermoplastics and thermosets using water soluble cores [patent: Valmet Transmec Ltd./Greencast Project Ltd.]; [inventor: Harri S. Sahari].The core moulding material consists of an inorganic core sand and inorganic binder. Cores must be coated with a material that is made especially for these cores. The cores as well as the coating are inorganic, ecologically safe, water soluble and recyclable.The whole process from mixing of the core material to the dissolving of the cores can be automated. The core production time is approximately equal to that required for injection moulding. As the investment and material costs are small, large scale production of lost cores is not necessary to achice economic production of moulded parts made from either thermosets or thermoplastics using the Greencast process.