Mechanism of Fume Suppression and Performance on Asphalt of Expanded Graphite for Pavement under High Temperature Condition

Fume suppression mechanisms and the effect of expanded graphite on the performance of asphalt were studied by applying infrared spectroscopy(FT-IR), X-ray diffraction(XRD), scanning electron microscopy(SEM) and comprehensive thermal analysis(TG, DSC). The experimental results confirm that asphalt which is mixed with expandable graphite will expand in the process of hot mix, and the expanded graphite layer will swell by the light component in the asphalt. The light component in the asphalt and PAHs adsorption on expanded graphite surface or part of the plug in the expanded graphite layer between plates made nucleation crystallization growth. And the Van der Waals force and the bonding of the lattice can effectively restrain the asphalt fume release. Meanwhile, the expanding agent with oxidative can spread into the asphalt, leading to asphalt oxygenated and plastic abate, while the ductility decreases. Expanded graphite, SBS modifier and environment- friendly plasticizers are used to composite modified asphalt. According to asphalt fume release experiment, normal test of asphalt performance, Brookfield viscosity test, RTFOT test and asphalt mixture tests(high temperature stability, low temperature stability, water stability), it has been proven that the modified asphalt's performance is better than that of matrix asphalt and equivalent to that of SBS modified asphalt. Furthermore, it has good fume suppression effect.     

改良型腰果酚醛树脂废气治理的研究

改良型腰果酚醛树脂应用到铸件等浸渍、粘合、烘干等过程中会产生恶臭,排放前需要降解处理。研究采用低温等离子体技术结合吸收方法处理改良型腰果酚醛树脂废气,考察了处理工程中峰值电压、停留时间、吸收液pH值对废气去除率的影响。实验室小试改良型腰果酚醛树脂废气进口浓度85 ppm,停留时间1.2 s时,去除率可达92%;工业扩大示范工程去除率最高可达80%,排气口出气平均恶臭浓度1 239.5(无量纲),满足《恶臭污染物排放标准》(GB14554-93)中相关规定。     

改性钢渣除藻效果研究

对改性钢渣在机械搅拌条件下的除藻效果进行了研究,并分析了改性钢渣预处理与混凝联用工艺对藻类的去除效果和协同作用.实验表明,钢渣经改性后,既能有效地去除水中的藻类,又能降低藻的光合活性,抑制藻的生长;高温活化改性钢渣预处理与混凝联用工艺对藻类有很好的去除效果,其对叶绿素a的平均去除率达91.4％,远高于单纯的钢渣预处理和混凝工艺.这暗示了两者之间在除藻方面存在协同作用.     

废旧聚乙烯的再生处理技术(上)

聚乙烯(Polyethylene)是塑料中产量极大、用途极广的热塑性塑料之一,它是由乙烯聚合而成,可用一般热塑性塑料的成型方法加工。聚乙烯可分为低密度聚乙烯(LDPE)、高密度聚乙烯(HDPE)和线型低密度聚乙烯(LLDPE)三大类。     

改进的工艺路线制备化学计量比的PZN基钙钛矿陶瓷

采用改进的工艺路线制备了化学计量比的Pb(Zn1/3Nb2/3)O3-PbTiO3-BaTiO3陶瓷,二氧化钛和碳酸钡不经过预烧,与预反应粉体混合球磨,成型后直接烧结,在1100℃和1120℃分别保温1 h,2 h,4 h获得了100%钙钛矿结构的PZN-PT-BT陶瓷,最大密度7.418 g/cm3,最大介电常数7672.     

酯硬化水玻璃再生砂循环使用后的性能变化及应对策略

分析了酯硬化水玻璃砂多次再生使用后,其Na2O含量较大升高、溃散性显著下降、生产厚大铸型(芯)时硬透性变差并出现蠕变现象的原因,探讨了再生砂性能变化后的应对策略。认为:研究开发适于干法再生水玻璃砂的改性水玻璃、对再生砂实施表面处理、对旧砂进行高脱膜率的再生等,应是解决酯硬化水玻璃砂多次再生使用后溃散性恶化问题的主要措施;而控制再生砂的含水量、适当增加有机酯的加入量、CO2气体补充硬化等,是增加型(芯)硬透性和克服蠕变现象的主要方法。     

Cu~(2+)对Fe~(2+)在T.f菌修饰粉末微电极上氧化行为的影响

Fe2 + 的氧化在细菌浸矿过程中具有重要作用 ,细菌浸铜过程中 ,Cu2 + 的存在对T .f菌的生长代谢和其氧化Fe2 + 的能力有一定影响。制备了T .f菌修饰碳粉粉末微电极 ,研究了Cu2 + 存在下Fe2 + 在T .f菌修饰粉末微电极上氧化的电化学反应机理 ,并测定了相应的电极过程动力学参数。循环伏安研究表明 ,Cu2 + 的存在不影响Fe2 + 在T .f菌修饰粉末微电极上的氧化反应的可逆性。对电极稳态及暂态过程研究表明 ,当Cu2 + 浓度在 12mmol/L以下时 ,Cu2 + 的存在不会抑制Fe2 + 在T .f菌修饰粉末微电极上的氧化 ,适量Cu2 + 加强T .f菌氧化Fe2 +的作用是在于其加快了电荷传递速率     

Corrosion protection of iron by polypyrrole modified by copper using the cementation process

Polypyrrole (PPy) coatings have been deposited on iron from aqueous oxalic acid solution at different current densities. The polymer deposit obtained at a current density of 2 mA cm⁻² yields strongly adherent and smooth PPy layers. The modification of the film by incorporation of copper microparticles using the cementation process was applied. The resulting PPy/Cu film electrodes were characterized by scanning electron microscopy and EDX analysis. The protective performance against corrosion of these films is evaluated by using open circuit potential monitoring in highly corrosive solution (3% NaCl + HCl, pH 1). The results obtained were promising in the protection against corrosion.     

聚氧化乙烯改性水玻璃粘结剂的研究

确定了聚氧化乙烯改性水玻璃粘结剂的基本组分,测试了有机酯自硬和CO2气硬型砂的常温粘结强度和高温残留强度。研究发现,在水玻璃中加入聚氧化乙烯树脂能改善水玻璃的老化现象,充分发挥其粘结效率;粘结剂加入量相同时,型砂强度是普通水玻璃砂的1.5倍,800～1000℃时,型砂残留强度≤0.5MPa。结果表明,聚氧化乙烯改性水玻璃粘结剂加入量低,型砂工艺性能良好,浇注后出砂容易,有利于旧砂进一步干法回用。     

Numerical solution of nonlinear system of Klein–Gordon equations by cubic B-spline collocation method

A technique to approximate the solutions of nonlinear Klein–Gordon equation and Klein–Gordon-Schrödinger equations is presented separately. The approach is based on collocation of cubic B-spline functions. The above-mentioned equations are decomposed into a system of partial differential equations, which are further converted to an amenable system of ODEs. The obtained system has been solved by SSP-RK54 scheme. Numerical solutions are presented for five examples, to show the accuracy and usefulness of proposed approach. The approximate solutions of both the equations are computed without using any transformation and linearization. The technique can be applied with ease to solve linear and nonlinear PDEs and also reduces the computational work.