研磨碳酸钙的胶乳改性及其在加填纸中的应用

采用胶乳对填料级研磨碳酸钙(GCC)进行表面改性,对改性GCC的基本性能及其加填性能进行了研究。结果表明,采用胶乳对GCC进行表面改性时,胶乳在GCC表面的吸附率超过了99%;经过胶乳改性后,填料的白度略有降低,填料平均粒径虽然变大但粒度分布变窄;与未改性GCC相比,改性GCC加填纸的强度性能得到明显提高,在胶乳用量为2.0%(对GCC)、保持纸张强度性能不变条件下,纸张灰分含量从15.8%提高到31.1%,同时光散射系数得到明显改善;且改性GCC可明显提高纸张的施胶性能。     

酸碱两步法改性硅灰石的表征及对纸张性能的影响

研究了经酸碱两步法改性处理后的硅灰石形态结构变化及作为填料对纸张性能的影响。结果表明,先用H2SO4使硅灰石部分溶解,然后调节p H值至碱性,以使溶出物质再沉积到颗粒表面,形成疏松多孔包覆层,在保持硅灰石原有针状形态的基础上,实现了硅灰石颗粒表面结构的重建。与未改性硅灰石相比,改性后硅灰石的粒径有所增加,白度提高;其加填纸的白度高、松厚度好、强度降低少。虽然改性硅灰石在纸张中的留着率低于未改性硅灰石,但高于GCC填料。     

钎焊温度对TC4与Ti3Al-Nb合金钎焊接头组织的影响

采用50Ti-20Zr-20Ni-10Cu粉末钎料对Ti3Al-Nb合金与TC4合金进行真空钎焊,通过SEM、EDS、电子探针及拉伸试验研究不同钎焊温度下钎焊接头的显微组织及性能特征.结果表明,钎焊温度升高钎焊接头强度并不提高;不同温度下钎焊接头中靠近TC4合金基体边界处均生成魏氏体组织,随温度升高魏氏体组织粗化程度加剧;整个钎焊接头中Ti3Al-Nb合金基体与钎料的反应程度弱于TC4合金基体.     

基于计算机视觉的纸张填料粒径分析方法

针对现有纸张填料粒径分析过程中使用的激光衍射法存在的缺点,提出一种基于计算机视觉的纸张填料粒径分析方法。将获取到的扫描电子显微镜图像进行预处理,去除噪声等影响统计粒径分布的因素,对图像中存在的填料颗粒粘连比较严重的部分采用改进的分水岭算法进行图像分割,进而利用快速连通域标记及欧拉数算法确定填料颗粒的粒径分布。最后将采用计算机视觉方法计算的填料颗粒粒径分布结果与采用激光衍射法得到的结果进行对比。在放大1500倍沉淀碳酸钙填料颗粒图像上的实验结果表明,采用计算机视觉方法计算的纸张填料粒径分布与激光衍射法测得的结果基本一致,中位径误差小于1%,累计粒度分布数达到85%时,误差在6%左右。     

国内碱锰电池用无汞锌粉的发展动态

从有害杂质、合金成分等化学组份,形貌、粒度分布、松装密度等物理性能方面,阐述了国产碱性锌锰电池用无汞锌粉近几年的技术进步;分析了国内无汞锌粉的市场现状和发展趋势;探讨了我国无汞锌粉工业存在的主要问题,我国无汞锌粉工业的崛起推动了碱锰电池产业的发展,同时,一定程度的盲目发展也面临着新的市场挑战;今后低铟锌粉将在市场中占主导地位。     

Review on nano-and microfiller-based polyamide 6 hybrid composite: Effect on mechanical properties and morphology

Polyamide 6 (PA6)-based composites are of evolving interest due to its high strength, wear resistance, and barrier properties. The use of binary composites mostly with nanomaterial and glass fibers has been reviewed and presented in literature. However to obtain a balance of properties like stiffness, toughness, and strength along with cost reduction, ternary composites of PA6 have been designed. To achieve the balance, PA6 blend-based composites, with combination of microfiller/nanofiller or PA6 with combination micro-microfiller, PA6 with microfiller/nanofiller and fiber have been designed. The properties of PA6-based ternary hybrid composites depend on type of dispersed phase used, presence of compatibilizer, type of filler used (nanofiller or microfiller or fiber or hybrid) and combination of fillers used. However, a review in this direction is not available in literature. Here, in this study, an overall understanding of various fillers, dispersed phase, and their combinations can be understood along with the discussion on effect of these on tensile properties and morphology of hybrid composite. In this study, an attempt has been made to review the various fillers and dispersed phase and their combinations which have been used in designing the PA6 hybrid composite with good balance of stiffness, toughness, and strength.     

One-step synthesis of high purity ZnO micro/nanostructures from pure Zn and pre-alloyed brass powders by vapor phase transport

In this research, vapor phase transport (VPT) was introduced as a facile, inexpensive method to produce ZnO micro/nanostructures from various Zn sources such as pure Zn and alpha brass pre-alloyed powders (Cu–20Zn and Cu–28Zn) at different processing temperatures of 930 °C–1050 °C. Simultaneous thermal analysis (STA) was carried out to investigate Zn evaporation and ZnO micro/nanostructure formation. STA results showed an exothermic peck at 711 °C and 728 °C for Cu–20Zn and Cu–28Zn, respectively, due to oxidation of the evaporated Zn element and formation of ZnO micro/nanostructures. X-ray diffraction results showed that high purity ZnO micro/nanostructures were successfully synthesized via VPT process and the crystallite size was increased from ~60 nm to ~100 nm with increasing processing temperature. Field emission scanning electron microscopy observations showed morphology (e.g. rods, column, tetrapods, and combs) and size of the synthesized micro/nanostructures were dependent on the Zn sources and processing temperature, in which average diameter of the synthesized ZnO structures was increased with increasing the processing temperature. The smallest (98 nm) and largest (603 nm) average diameters of synthesized ZnO micro/nanostructures were attained from the pure Zn and Cu–28Zn brass powders at 930 °C and 1050 °C, respectively.     

复杂流道结构料仓的下料流率预测

在实验室搭建的有机玻璃料仓下料平台上,分别以自由流动粉体玻璃微珠和黏附性粉体煤粉和聚氯乙烯为实验介质,针对无改流体(No-In)、封闭改流体(Con-In)和开放改流体(Ucon-In)三种情况所形成的不同流道结构,开展了粉体料仓下料及其流率建模研究,定量分析了改流体对粉体下料流率的促进作用,对比给出了玻璃微珠、煤粉和聚氯乙烯在不同流道结构料仓内的下料特性。研究表明,改流体的引入有利于提高料仓下料流率,Con-In促进流动效果最明显,对于流动性弱的煤粉,下料流率提升幅度达到最大的58%。基于剪切摩擦区的概念,提出流率校正因子F对最小能量理论方程进行了修正,将理想的料仓下料模型拓展至实际下料过程。进一步,对于Con-In,根据流道结构特征结合对粉体的受力分析,修正了模型中的锥角项;对于Ucon-In,基于粉体下料流动竞争机制,提出分阶段下料模式并关联了内层和夹层的下料流率,最终建立了复杂流道结构料仓的下料流率预测模型。该模型综合考虑了粉体物性、下料流型和流道结构的影响,可有效预测自由流动粉体和黏附性粉体流经传统料仓(No-In)和改流体料仓(包括Con-In和Ucon-In)的粉体下料流率,且预测偏差<10%。     

含铜废水预处理设施脱氮升级改造工程

为了减轻太湖保护区范围内企业处理废水的负担,苏州白荡污水处理厂利用其含铜废水预处理设施的富余处理能力处理某公司产生的含氮废水。针对含氮废水高NO3^--N和低碳氮比等特点,在充分利用原处理设施的基础上,采用"A/O+固定床生物膜工艺+高效脱氮填料+乙酸钠碳源+内回流"组合工艺对含铜废水预处理设施进行脱氮升级改造。改造后实际运行结果表明,设施运行稳定,出水水质达到出水水质达到设计出水要求,TN和NH4^+-N的去除率分别达到85.4%和82.3%,Cu的去除率提高了17.6%。     

铁碳填料对电镀清洗废水的微电解性能

以硫铁矿烧渣为主要材料制备了球形铁碳填料,并将其用于电镀清洗废水的处理。由交互正交试验结果可知,废水pH值是影响COD和氨氮去除率的主要因素,其次是废水pH值与铁碳填料添加量的交互作用和废水pH值与反应时间的交互作用。微电解的最佳工艺条件为:废水pH值2.50,铁碳填料的添加量15 g/L,反应时间30 min。此时,COD降低78.6%,氨氮降低15.0%,处理效果比商品铁碳填料的好。