废橡胶粉对混合砂浆性能影响的研究

系统测试和分析了新拌混合砂浆和易性和硬化砂浆轴心抗压强度、静力受压弹性模量、泊松比、干表观密度、导热系数、干燥收缩率随三元乙丙(EPDM)橡胶粉代砂体积分数增加的变化程度和规律.橡胶粉可以改善新拌混合砂浆的和易性,降低硬化混合砂浆强度、弹性模量、表观密度和导热系数,提高其泊松比和干燥收缩率.低弹性模量、高泊松比、高干缩值橡胶粉混合砂浆将使其更能适应新型墙体材料性能的要求,有利于减小墙体裂缝的产生;低表观密度、低导热系数橡胶粉混合砂浆将有利于提高墙体的隔热保温性能.     

用钡渣制取硫酸钡

用盐酸浸取钡渣，所得的氯化钡溶液再和硫酸反庆，得到硫酸钡沉淀，母液返回去浸取钡渣。浸取钡渣的适宜条件为：浸取时间５０ｍｉｎ、ｐＨ２－３、钡渣粒度１２０目、浸取温度４０－４５℃、液固比３：１。     

平流层硫酸盐气溶胶辐射效应的模拟研究

平流层中的硫酸盐气溶胶在地球能量循环和全球气候变化中发挥着关键性作用.基于自主开发的矢量辐射传输模型,重点研究对流层气溶胶类型、平流层气溶胶光学厚度(AOD)、太阳天顶角(SZA)和地表反照率等对平流层硫酸盐气溶胶辐射强迫和大气加热速率等辐射效应的影响.结果表明,对流层无气溶胶时,平流层气溶胶在大气顶层(TOA)的辐射强迫为-15.80 W·m^-2,地气系统的冷却效应最大.对流层气溶胶为黑碳时,平流层气溶胶在大气底层(BOT)的辐射强迫最小,为-47.53 W·m^-2,地表冷却最大.同时,平流层硫酸盐的辐射强迫导致对流层降温,平流层升温,在模拟条件下,最大升温可达0.6 K·d^-1.此外,结果还表明,平流层硫酸盐辐射强迫对AOD、SZA和地表反照率均具有很高的敏感性.平流层气溶胶在TOA和BOT的辐射强迫随AOD的增大呈线性减小趋势,但随地表反照率的增大呈线性增大趋势.AOD和SZA的增大会强化辐射强迫的作用效果,但地表反照率的增大可能会改变辐射强迫的正负,导致平流层硫酸盐对地气系统的作用效果从冷却变为加热.     

紫外分光光度法测定水中挥发酚的研究

目前,测定水中挥发酚一般采用4-氨基安替比林直接比色法和萃取法.为了克服4-氨基安替比林比色法测定挥发酚时需蒸馏、试剂不稳定等缺点或不足,提高挥发酚的检测上限,本文提出用紫外光度法测定水中挥发酚.用浓磷酸固定水样,用三氯甲烷、乙醚萃取水样,使挥发酚转移到乙醚中,排除多种离子的干扰;加入无水硫酸钠脱水,用乙醚定容,269 nm处测定吸光度.此方法不仅使测定范围增大到0.409～120 mg/L,且简便、快速、准确.本方法与标准方法有很好的可比性,同时,有很好的重现性.     

不同配比安全点火药B/KNO_3的研究

为研究可靠点燃主装药,性能稳定的B/KNO3点火药,对不同配比的B/KNO3进行配制并对其性能进行测试。不同配比B/KNO3在火焰感度、静电火花感度、撞击感度、摩擦感度4项外界刺激中,除了对撞击非常钝感之外,对其他3项外界刺激敏感。在不同比例的药中,以B/KNO3比例为50:50,粘结剂为X的药火焰感度最高,稳定性好;静电火花感度随B/KNO3中B比例提高而降低,摩擦感度随B/KNO3中B比例提高而提高,但当中B比例从40%提高到50%时,这两感度改变不多。分析得出B/KNO3比例为50:50,粘结剂为X的药满足对主装药点火可靠,稳定性好。     

Effect of SiO2 addition on NH4HSO4 decomposition and SO2 poisoning over V2O5–MoO3/TiO2–CeO2 catalyst

The deposition of NH₄HSO₄ and the poisoning effect of SO₂ on SCR catalyst are the main obstacles that restrict the industrial application of CeO₂-doped SCR catalysts. In this work, deposited NH₄HSO₄ decomposition behavior and SO₂ poisoning over V₂O₅–MoO₃/TiO₂ catalysts modified with CeO₂ and SiO₂ were investigated. By the means of characterization analysis, it was found that the addition of SiO₂ into VMo/Ti–Ce had an impact on the interaction existed between catalyst surface atoms and NH₄HSO₄. Temperature-programmed methods and in situ diffused reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments indicated that the doping of SiO₂ promoted the decomposition of deposited NH₄HSO₄ on VMo/Ti–Ce catalyst surface by reducing the thermal stability of NH₄HSO₄ and enhancing the NH₄HSO₄ reactivity with NO in low temperature. And this improvement may be the reason for the better catalytic activity than VMo/Ti–Ce in the case of NH₄HSO₄ deposition. Accompanied with cerium sulfate species generated over catalyst surface, the conversion of SO₂ to SO₃ was inhibited in SiCe mixed catalyst. The addition of SiO₂ could promote the decomposition of cerium sulfate, which may be a potential strategy to enhance the resistance of SO₂ poisoning over CeO₂-modifed catalysts.     

用甲基硫酸钠废渣制备二甲基硫醚

根据酯在碱性条件下水解反应生成醚的原理，研究了以甲基硫酸钠废渣为原料制备二甲基硫醚（DMS）的方法。在反应温度100℃、加水量100mL、搅拌时间30min、合成反应时间50min的最佳工艺条件下，制得的DMS产品纯度为99％，收率为83．59％。该法工艺简单，技术可行，操作稳定，既消除了环境污染，又能制备化工产品，具有明显的环境效益和经济效益。     

Microbially Mediated Redox Cycling at the Oxic–Anoxic Boundary in Sediments: Comparison of Animal and Plants Habitats

Microorganisms are responsible for the bulk of transformations that occur in surficial sediments. They are most active at redox boundaries where they can benefit from access to various oxidants and reductants generated during redox cycling events. To illustrate the dynamics of microbially mediated processes, especially those involving sulfur and metal cycles, processes were compared in habitats either bioturbated by a capitellid worm or inhabited by a salt marsh grass. The presence of macrofauna and macroflora greatly altered the three-dimensional array of redox gradients in sediments, but the type and form of reductants and oxidants provided varied greatly; clastic sedimentary infauna subducted solid phase organic material and iron oxides, whereas plant roots released dissolved organic matter and oxygen. These differences resulted in a bioturbated system that exhibited a rapid sulfur cycle (residence time of minutes), but a slower iron cycle (days), whereas vegetation caused a slow sulfur cycle and rapid iron cycle. Alteration of sediments by higher life forms also greatly affected the composition and relative abundances of sedimentary bacteria, even on short time scales. Although redox cycling at interfaces can be somewhat predictable, variations in response to biological and physical perturbations demonstrated wide differences in the dynamics of redox-mediated processes.     

从萘系高效减水剂中分离硫酸钠的清洁工艺

对萘系高效减水剂中硫酸钠的分离提出了一种用有机醇作为促析剂的分离工艺,在较高温度和较高的水剂总浓度下,按水剂质量的３０％加入促析剂,可使粉剂中硫酸钠的质量分数降至３％以下,促析剂可回收利用。该工艺无三废排放,工艺简单,可望取代传统的脱硫酸钙法。     

湖泊沉积物中硫的地球化学循环机制研究

湖泊沉积物中的硫是控制氧化还原体系的重要元素之一。湖泊硫酸盐还原作用主要发生在沉积物表层几厘米范围内,界面硫酸盐还原具有双重环境效应。硫酸盐还原主要形成黄铁矿和有机硫,黄铁矿的生成要受到沉积物中硫酸盐、有机质以及铁氧化物活性的控制。单硫化物不稳定,并且会影响沉积物中重金属的迁移。