膨化硝酸铵自敏化理论研究

膨化硝酸铵自敏化理论是膨化技术发明的核心,它是基于热点理论把微气泡植入硝酸铵炸药中。微气泡临界热点温度热力学计算为自敏化提供理论依据。与普通硝酸铵及珍珠岩相比较,微气泡在膨化硝酸铵内适当的分布为自敏化成功提供了有力的保证。     

硝酸铵自敏化的基本原理和技术途径

低成本和优性能的无梯粉状硝铵炸药是工业炸药发展的趋势之一，其中硝酸铵自敏化是关键的技术途径。文中基于爆炸理论和化学原理，对硝酸铵自敏化的可能途径进行了分析和论述，主要有微气泡自敏化、晶格缺陷自敏化、晶变自敏化、晶体活化敏化和表面自敏化等。     

硝酸铵膨化技术及应用

硝酸铵膨化技术是一创新技术,创新设计的指导思想是硝酸铵自敏化,硝酸铵自敏化的提出是对国内外传统方法的突破。实施自敏化的技术途径是硝酸铵的膨化,其实质是表面活性技术在粉状炸药中的应用,是一个强制析晶的物理化学过程。文章重点讨论了硝酸铵膨化机理及膨化硝酸铵的技术特征,显示其独特的优点。硝酸铵膨化技术主要应用是岩石膨化硝铵炸药,给出了岩石膨化硝铵炸药的爆炸与物理特征数据,并与其它工业炸药做了比较。同时也推广应用在煤矿许用型炸药中。     

膨化硝酸铵的微观结构研究

文章对膨化硝酸铵、普通硝酸铵进行晶形电镜扫描,研究了其孔径与孔容分布、粒径分布、比表面积测定及DSC实验,揭示了膨化硝酸铵的微观结构,说明了膨化硝酸铵具备自敏化的结构特征.     

浅谈提高岩石膨化硝铵炸药密度的方法

由于膨化硝酸铵具有大量的敏化微气泡,使岩石膨化硝铵炸药的密度降低,相应的单位体积装药量少,炮孔的利用率低。文章从岩石膨化硝铵炸药的组成及生产工艺入手,对提高岩石膨化硝铵炸药密度的一些常见方法进行了探讨。添加的材料A具有原料来源广,价格与硝酸铵相当,加入工艺简单,可实现连续化生产,生产过程安全性好,能显著提高岩石膨化硝铵炸药密度等特点。     

文摘

具有高抗水性的炸药组成;多孔粒状硝酸铵和乙醇或甲醇混合物的爆炸特性值;爆破炸药及其制造;膨化硝酸铵自敏化理论基础与实验研究;LRH—A型乳化炸药中用的复合剂     

膨化硝铵炸药中添加乳化基质的研究

通过表面活生剂对硝酸铵进行处理制得的自敏化膨化硝酸铵,应用这种膨化硝酸铵作氧化剂和敏化剂,再辅助以乳化基质制得的复配型炸药能进一步提高岩石膨化硝铵炸药的爆破效果。试验结果表明,这种炸药具有良好的使用性能。     

测试密度对膨化硝酸铵微观结构表征的影响

文章利用NOVA1000比表面积测试仪,测试了膨化硝酸铵在堆积密度和晶体密度下的孔径分布、累积孔面积和累积孔体积、比表面积以及孔容等微观结构参数,并比较了两种密度下表征膨化硝酸铵的微观结构参数的差异.结合理论分析和测试数据可知,利用硝酸铵的晶体密度进行测试可以更精确地表征膨化硝酸铵的微观结构,避免了因测试堆积密度而导致的测试误差,能够更好地理解硝酸铵的自敏化理论.     

多元易发泡型复合乳化剂乳化炸药的制备

文章论述了一种多元易发泡型复合乳化剂,它含水溶性和油溶性两种类型的乳化剂,能将内相中硝酸铵溶液极个别硝酸铵分子外移至外相,与亚硝酸钠水溶液NO2相遇后,即产生气泡（N2）,使乳胶基质敏化成乳化炸药,消除了化学敏化中二元敏化、后效及混合不均匀的问题。     

膨化硝铵炸药密度添加剂的研究

通过表面活性剂对硝酸铵进行处理,制取敏化膨化硝酸铵,存在装药密度偏低、威力相对减少的现象.添加密度添加剂能解决此问题,并能提高爆破使用效果.     

Breath Figures as a Dynamic Templating Method for Polymers and Nanomaterials

This review describes the use of breath figures as a templating method for the fabrication of self‐assembled polymeric‐ and nanoparticle‐based micro‐ and nanostructures. If moist air is blown over a solution of a polymer or stabilized nanoparticles in an organic solvent, such as carbon disulfide, benzene, or chloroform, evaporative cooling leads to the formation of water droplets on the liquid surface. The monodisperse droplets arrange into a hexagonal array and sink into the polymer solution. Removal of the solvent and the water leaves an imprint of the water droplets as a hollow, air‐filled, hexagonally ordered, polymeric bubble array. Progress in the field of breath‐figure formation is reviewed. The application of breath figures for the generation of functional structures in chemistry and materials science is discussed.     

全自动粉状硝铵炸药生产技术的分析和设计

通过对硝酸铵敏化机理的研究,探求无梯硝铵炸药影响敏化的主要因素,以及无梯硝铵炸药选择硝铵改性进行敏化的可行路线,介绍了全自动粉状硝铵炸药自动化连续化工业生产的工艺过程。     

基于多相流的LCM工艺气泡生成仿真

分析了液体模塑成型工艺（LCM）下织物预成型体中双尺度流动以及由此造成的空气裹入,进而产生细观及微观气泡的现象。基于多相流（VOF）方法建立了树脂空气两相流体在单胞内部流动的数学模型,并确定了该模型中多孔介质阻力源项和毛细力源项的具体形式。基于Fluent软件的UDF功能实现了上述两相流模型的数值求解,研究了平纹织物单胞中的两相流动以及2种气泡的生成过程。对Rovcloth 2454织物的气泡生成仿真结果显示,毛细数 Ca 对气泡的产生有决定性作用：当毛细数接近临界毛细数 Ca^c时,气泡产生量最低,而当Ca小于Ca^c时,容易产生细观气泡,反之容易产生微观气泡。通过与文献中的理论预测和实验数据对比,验证了本文算法的正确性。     

Water modelling of effects of pouring basin and sprue geometry on entrance of air bubbles into mould

Abstract

It has been shown that passing of air through molten metal can have a great contribution to the formation of oxide defects in casting of aluminium alloys. In gravity casting of these alloys, the design of gating system has a considerable effect on the formation of air bubbles and their behaviour afterwards. This paper is aimed to study the effect of pouring basin and sprue design on the quantity of air bubbles entering the mould cavity. In order to do this, water modelling of pouring into several gating systems varying in pouring basin and sprue design was conducted, and quantified results were used to compare the designs in terms of the ability to prevent bubble formation and entrainment. It was concluded that the offset basin with a 1 in. high barrier in bottom is the most efficient design in preventing bubble entrainment.     

Two-phase bubbly flows in microgravity: Some open questions

Several studies on gas-liquid pipe flows in micro gravity have been performed. They were motivated by the technical problems arising in the design of the thermohydraulic loops for the space applications. Most of the studies were focused on the determination of the flow pattern, wall shear stress, heat transfer and phase fraction and provided many empirical correlations. Unfortunately some basic mechanism are not yet well understood in micro gravity. For example the transition from bubbly to slug flow is well predicted by a critical value of the void fraction depending on an Ohnesorge number, but the criteria of transition cannot take into account the pipe length and the bubble size at the pipe inlet. To improve this criteria, a physical model of bubble coalescence in turbulent flow is used to predict the bubble size evolution along the pipe in micro gravity, but it is still limited to bubble smaller than the pipe diameter and should be extended to larger bubbles to predict the transition to slug flow. Another example concerns the radial distribution of the bubbles in pipe flow, which control the wall heat and momentum transfers. This distribution is very sensitive to gravity. On earth it is mainly controlled by the action of the lift force due to the bubble drift velocity. In micro gravity in absence of bubble drift, the bubbles are dispersed by the turbulence of the liquid and the classical model fails in the prediction of the bubble distribution. The first results of experiments and numerical simulations on isolated bubbles in normal and micro gravity conditions are presented. They should allow in the future improving the modelling of the turbulent bubbly flow in micro gravity but also on earth.     

Antifouling on Gecko's Feet Inspired Fibrillar Surfaces: Evolving from Land to Marine and from Liquid Repellency to Algae Resistance

In nature, biological creatures (including plants and animals) have self‐cleaning capability despite the vagaries of the environment, i.e., from sky to land, and then to marine and vagaries of foulants (non‐living and living). Gecko's feet have the general self‐cleaning property both in air and underwater so as to keep their feet all clean for traveling through changing their adhesion. The present work reports Gecko's fibrillar structures to demonstrate general antifouling property in air through hydrophobicity and underwater after modification with hydrophilic polymer brushes. Fibrillar polypropylene (PP) nanoarrays are fabricated by hot embossing, exhibiting superhydrophobic antifouling in air. By grafting hydrophilic polyelectrolyte brushes (PSPMA) via surface‐initiated atom transfer radical polymerization, they show superoleophobic antifouling of oil droplet and algae adhesion underwater. The effect of the structure of PP nanofiber arrays on the wettability and adhesion behavior is evaluated in detail. The results provide an important scientific principle for fabricating self‐cleaning low‐fouling materials with micro/nanostructure, with the hydrophobic ones being more applicable in air and the hydrophilic ones well suited underwater.     

Electrical breakdown voltage of transformer oil with gas bubbles

Electrical breakdown strength of liquid-gas micro bubble mixtures of transformer oil with sulfur hexafluoride and air for the case of quasi homogeneous gas inclusions distribution and 10% volumetric gas content was experimentally investigated. DC voltage up to 140 kV was applied to a 8 mm gap between hemispherical electrodes. It is shown that transformer oil bubbled with air leads to threshold breakdown voltage decrease by 34% and 19% when bubbled with sulfur hexafluoride. The stabilization effect of sulfur hexafluoride micro bubbles on the value of threshold breakdown voltage is observed.