Synergistic Flame Retardant Effects of Carbon Nanotube-Based Multilayer Nanocoatings

In an effort to develop highly functionalized flame retardant materials, hybrid nanocoatings are prepared by alternately depositing a positively charged polyaniline (PANi) and negatively charged montmorillonite (MMT) using the layer-by-layer (LbL) assembly technique. Carbon nanotubes (CNTs) are employed in polymer nanocomposites as effective reinforcement, where nanotubes are stabilized in MMT aqueous solution. The 3D structure and high density of CNTs deposited in the PANi/CNTs-MMT multilayers produce thicker and heavier coatings in comparison to the LbL assemblies without CNTs. Vertical and horizontal flame testing show that the incorporation of CNTs improves fire resistance. Additionally, cone calorimetry reveals that stacking two nanomaterials (MMT and CNTs) in a single coating shows a significant reduction in peak heat release rate (up to 51%), total smoke release (up to 47%), and total heat release (up to 37%) for the polyurethane foam. The enhancement of flame retardancy is attributed to a synergistic effect; MMT serves as a physical barrier that retards the diffusion of heat and gas. The addition of CNTs strengthens the thermal stability and high char yield. These results, coupled with the simplicity with which the LbL deposition is applied, present a viable alternative to halogen-free flame retardant nanocoatings to natural and synthetic fibers.     

Natural Polysaccharides as Multifunctional Components for One-Step 3D Printing Tough Hydrogels

Natural polysaccharides (NPS) are regarded as biomolecular and structural components for preparing high-performance tough hydrogels. But the one-step fabrication of NPS-containing hydrogels in seconds and the template-free design of complicated high-resolution structures are still significant challenges in this field. To meet these requirements, various NPS-containing tough hydrogels are fabricated and processed into 2D/3D structures via the combination of Ru(bpy)₃²⁺-mediated photochemistry and extrusion 3D printing technique. The whole fabrication process is one-step, completed in tens of seconds under visible light irradiation. It is found that the used NPS plays a key role in achieving the fabrication of high-performance structured tough hydrogels. The high reactivity of functional groups in the used NPS can shorten their gelation times. Long rigid chains of the used NPS, their hierarchical assemblies, and contrasting multinetworks benefit from the efficient dissipation of mechanical energy and enhancement of its operational stability. Strong supramolecular interactions enable hydrogel precursors to have high viscosities, therefore providing good controllability to design high-resolution and complicated tough hydrogel structures via extrusion 3D printing. It is anticipated that this straightforward fabrication strategy and findings will open new horizons for NPS-containing materials.     

脉内无固废精准开采采矿方法在嵩县山金的应用

嵩县山金北翼矿体走向长度短、平均厚度薄、矿体倾角小、地质品位低、岩石稳固性较差,采用盘区机械化上向水平分层进路充填采矿法开采,采切工程投入大,成本费用高,安全投入及风险更大。针对该类矿体,提出了一种脉内无固废精准开采采矿方法,通过构筑人工假巷形成运输条件,人工架设钢溜井形成行人、放矿、通风、泄水条件,采矿工作完成后通过脉内悬吊1 m³铲运机完成机械化出矿及设备换层工作,采用分层充填采矿法充填采空区,提高回采效率。与原采矿方法进行技术经济对比,采用脉内无固废精准开采采矿方法经济效益更好,不需要布置分段巷、采场联巷等掘进工程,在工程投入方面可节约23.2万元,不产生掘进废石,实现了脉内无固废开采的目的。现场试验结果表明：该开采方法具有开采精度高、采（出）矿效率高、采矿损失贫化低、安全投入小、经济效益高等优点,推广前景较大。     

炼厂硫腐蚀的典型案例分析及解决措施

通过硫在不同温度与环境下对金属材料腐蚀的典型案例分析，简述其腐蚀机理与解决,工对今后炼厂高硫油加工提出进一步建议。     

THE STRUCTURE CONTROL OF ALUMINUM FOAMS PRODUCED BY POWDER COMPACTED FOAMING PROCESS

A new technique, powder compact foaming process for the production of aluminum foams has been studied in this article. According to this method, the aluminum powder is mixed with a powder foaming agent (Till2). Subsequent to mixing, the powder blend is hot compacted to obtain a dense semi-finished product. Upon heating to temperatures within the range of the melting point, the foaming agent decomposes to evolve gas and the semi-finished product expands into a porous cellular aluminum. Foaming process is the key in this method. Based on experiments, the foaming characteristics were mainly analyzed and discussed. Experiments show that the aluminum-foam with closed pores and a uniform cell structure of high porosity can be obtained using this method by adjusting the foaming parameters: the content of foaming agent and foaming temperature.     

WZ型系列真空铝钎焊炉的研制

简要介绍了WZ型系列真空铝钎焊炉型号，规格等技术参数，并以WZLQH－30型真空铝钎焊炉为例介绍了真空铝钎焊炉的结构及其特点，总结了真空铝钎焊炉设计研究及调试过程中的一些经验体会。     

液压夹轨装置夹不紧原因分析及夹轨装置的改造

本文通过对液压夹轨装置结构和机理分析，指出原设计夹轨装置预留压紧量(Smax-S)不足是导致夹轨装置锁不紧的主要原因，并对相应间隙和零件进行了调整和改造，解决了拖车的锁紧问题。     

装备维修技术的发展及表面工程技术的应用

在研究未来维修技术发展特点及趋势的基础上，提出装备维修技术的发展方向和重点是装备状态监测、故障诊断与预测技术，装备修复关键技术，装备维修保障综合化信息化关键技术，装备延寿与再制造技术，装备维修技术创新性研究以及装备现场抢修技术。指出纳米颗粒复合电刷镀技术、高速电弧喷涂技术、纳米固体润滑干膜技术、纳米减摩与原位动态自修复技术等先进而实用的表面工程新技术、新材料、新设备、新工艺，对实现装备维修的快速化、自动化、智能化、信息化将发挥重要作用。     

CoCrPtNb／CrTi／C多层膜记录介质的制备和性能研究

采用CoCrPtNb四元合金作磁记录介质，并采用多层膜结构（CoCrPt）100-Nbx/CrTi／C／Glass制备玻璃盘基硬盘。实验结果表明：采用适宜厚度的籽晶层与合适组分的底层和磁性层的多层膜结构，即使在室温下溅射，此种薄膜磁记录介质也可得到高达260kA／m的矫顽力；在550℃高温下，经过30min真空退火后，其矫顽力有较大幅度提高，并在Nb含量为2．4％（原子分数）时达到极大值386kA／m，适用于高密度磁记录。同时，也详细分析了磁性层和底层组分、籽晶层厚度以及真空退火对磁记录介质磁性能和微结构的影响。