用颗粒冲击磨损试验评价热喷涂陶瓷涂层的粒子间结合

热喷涂层中扁平粒子间的结合决定涂层的性能。能评价粒子间结合的简单可靠的方法对于涂层的实际应用具有十分重要的意义。然而采用传统的试验方法如拉伸试验难以获得令人满意的结果。可以预料具有去结合机理的一层接一层去除粒子的试验方法将是有效的。实验证明通过控制测试条件，颗粒冲击磨损试验能够通过去结合机理有效地使涂层产生磨损。本论文提出了陶瓷涂层颗粒冲击磨损的模型，基于涂层受颗粒冲击磨损是因一层层的粒子通过去结合而产生的机理，建立了磨损速度与粒子间结合率的关系。定义为ACT－JP值（磨损速度的倒数）的特征值与粒子间结合率的实验相关性证明了粒子间结合对陶瓷涂层磨损的控制作用和利用颗粒冲击磨损试验评价粒子间结合的可行性。     

Decolorization of reactive brilliant red X-3B by heterogeneous photo-Fenton reaction using an Fe–Ce bimetal catalyst

Decolorization of reactive brilliant red X-3B was studied by using an Fe–Ce oxide hydrate as the heterogeneous catalyst in the presence of H₂O₂ and UV. The decolorization rate was in the order of UV–Fe–Ce–H₂O₂ > UV–Fe³⁺–H₂O₂ > UV–H₂O₂ > UV–Fe–Ce ≥ Fe–Ce–H₂O₂ > Fe–Ce. Under the conditions of 34 mg l⁻¹ H₂O₂, 0.500 g l⁻¹ Fe–Ce, 36 W UV and pH 3.0, 100 mg l⁻¹ X-3B could be decolorized at efficiency of more than 99% within 30 min. The maximum dissolved Fe during the reaction was 1 mg l⁻¹. From the fact that the decolorization rate of the UV–Fe–Ce–H₂O₂ system was significantly higher than that of the UV–Fe³⁺–H₂O₂ system at Fe³⁺ = 1 mg l⁻¹, it is clear that the Fe–Ce functioned mainly as an efficient heterogeneous catalyst. UV–vis, its second derivative spectra, and ion chromatography (IC) were employed to investigate the degradation pathway. Fast degradation after adsorption of X-3B is the dominant mechanism in the heterogeneous catalytic oxidation system. The first degradation step is the breaking down of azo and CN bonds, resulting in the formation of the aniline- and phenol-like compounds. Then, the breaking down of the triazine structure occurred together with the transformation of naphthalene rings to multi-substituted benzene, and the cutting off of sulphonic groups from the naphthalene rings. The last step includes further decomposition of the aniline structure and partial mineralization of X-3B.     

新型煤粉燃烧器的特性分析和产能发挥探索

实践证明,一次风用量、风道风速、旋流风的旋转和扩散、风压、二次风温、喂煤系统的计量准确性和稳定性是影响燃烧器性能发挥的主要因素。燃烧器的调试工作是一个复杂的系统工程,必须有计划、按步骤进行。燃烧器在使用中,要加强检查维护,对出现的损伤要及时进行修理。     

催化热裂解工艺机遇及影响因素

分析了催化热裂解过程的反应机理及乙烯和丙烯形成的反应，乙烯和丙均可通过热裂解和催化裂解生成，讨论了影响乙烯，丙烯产率的因素：与USY和REY相比，使用ZSM－5催化剂能够提高乙烯，丙烯产率，磷改性ZRP－1经碱土金属改性后，可进一步提高乙烯和丙烯的产率，提高反应温度和降低剂油比，能够提高热裂解和催化裂解的比例，有利于乙烯产率的提高；增强蒸汽量能够减少焦炭产率，提高乙烯和丙烯产率。     

Tri-pyramid Robot: Design and kinematic analysis of a 3-DOF translational parallel manipulator

3-DOF translational parallel manipulators have been developed in many different forms, but they still have respective disadvantages in different applications. To overcome their disadvantages, the structure and constraint design of a 3-DOF translational parallel manipulator is presented and named the Tri-pyramid Robot. In the constraint design of the presented manipulator, a conical displacement subset is defined based on displacement group theory. A triangular pyramidal constraint is presented and applied in the constraint designs between the manipulator?s subchains. The structural properties including the decoupled motions, overconstraint elimination, singularity free workspace, fixed actuators and isotropic configuration are analyzed and compared to existing structures. The Tri-pyramid Robot is constrained and realized by a minimal number of 1-DOF joints. The kinematic position solutions, workspace with variation of structural parameters, Jacobian matrix, isotropic and dexterity analysis are performed and evaluated in the numerical simulations.     

Oxygen reduction on platinum electrodes in base: Theoretical study

Electrode-potential-dependent activation energies for electron transfer have been calculated using a local reaction center model and constrained variation theory for the oxygen reduction reaction on platinum in base. Results for four one-electron transfer steps are presented. For the first, O₂(ads) is predicted to be reduced to adsorbed superoxide, O₂⁻(ads), which dissociates with a low activation barrier to O(ads) + O⁻(ads). Then a proton transfer form H₂O(ads) to O⁻(ads) takes place, forming OH(ads) + OH⁻(aq). The second electron transfer reacts O(ads) with H₂O(aq) to form a second OH(ads) + OH⁻(aq). The third and fourth electron transfers react the two OH(ads) with two H₂O(aq) to form two H₂O(ads) + two OH⁻(aq). All three different surface reduction reactions are predicted to have reversible potentials in the −0.24 V(SHE) to −0.29 V(SHE) range for 0.1 M base and activation energies for the superoxide formation step are close to the experimentally observed range in 0.1 M base for the overall four-electron to water over the three low index (1 1 0) (1 0 0) and (1 1 1) surfaces: 0.38-0.49 eV at 0.35 eV respectively at 0.88 V(RHE). Predicted reversible potentials for forming O₂⁻(ads) are compared with estimates from the experimental literature. The difference between the acid mechanism, where the peroxyl radical, OOH(ads) is the first reduction intermediate, and the base mechanism, where superoxide, O₂⁻(ads) is the first reduction intermediate, is discussed.     

乙烯-丙烯酸甲酯共聚物对蜡的作用机理

利用偏光显微镜和微电泳仪研究了乙烯-丙烯酸甲酯共聚物(EMA)对蜡晶的形态和电性质的影响。结果表明:EMA加入原油后,使原油中的蜡晶形成小的晶体,改善了原油的流变性性能;降凝剂EMA的加入可使蜡晶表面带电,电性排斥使蜡晶高度分散而稳定存在;当EMA用量较低时,蜡晶表面ζ电位随降凝剂用量增加而增加,当EMA用量较高时,蜡品表面与电位随降凝剂用量的增加趋势变缓;EMA的用量达到一定值时,蜡晶表面ζ电位不随降凝剂含量的增加而变化。     

碱金属和锌对高炉用SiAlON结合刚玉砖的复合侵蚀

将高炉用SiAlON结合刚玉砖制成外部尺寸为50mm×50mm,内孔尺寸为25mm×25mm的坩埚,分别加入由Na2CO3、K2CO3、ZnO和宝钢高炉现场高炉灰配制的炉渣(其w(Na2O+K2O)=2.75%,w(ZnO)=5.1%)和用K2CO3、ZnO、石墨配制的炉渣(其w(Na2O+K2O)=25%,w(ZnO)=25%),然后分别在还原气氛下于1350℃16h和1100℃40h进行侵蚀试验。将侵蚀后的试样纵向对称剖开,观察渣对试样的侵蚀和渗透情况,进行SEM和EDAX分析。结果表明:碱金属和锌含量不同的两种炉渣对SiAlON结合刚玉砖的侵蚀速度都很小;碱金属侵蚀机理主要是SiAlON与碱蒸气反应生成钾霞石,与渣反应生成铁橄榄石,并参与硅酸盐玻璃相的生成;刚玉颗粒与渣中的FeO、Na2O和K2O反应生成铁铝尖晶石和少量针状β-Al2O3;锌对该砖没有产生明显的化学侵蚀。     

针铁矿法沉铁过程亚铁离子浓度预测

针对针铁矿法沉铁过程出口亚铁离子浓度离线化验获得,存在很大滞后性,难以实现沉铁过程实时控制的问题,研究反应器出口亚铁离子浓度在线预测方法.本文在分析沉铁过程化学反应机理的基础上,考虑铜离子对反应过程的影响,结合连续搅拌反应器（Continuous stirred tank reactor,CSTR）特性,建立了针铁矿法沉铁过程的机理模型,并提出了基于信息交换的双粒子群搜索算法（Double particle swarm optimization,DPSO）优化选择机理模型的参数,构建基于最小二乘支持向量机（Least squares support vector machine,LS-SVM）的机理模型输出误差的补偿模型,采用并联补集成方式建立了亚铁离子浓度的集成预测模型.工业现场数据验证了所建模型能有效地反映亚铁离子浓度的变化趋势,为针铁矿法沉铁过程的优化控制奠定了基础.     

Growth and formation mechanism of sea urchin-like ZnO nanostructures on Si

Sea urchin-like nanostructures of ZnO consisting of ZnO nanowires with blunt faceted ends were grown on Si (100) substrates by oxidation of metallic Zn at 600 °C. ZnO nanowires having a diameter of 30–60 nm and length of 2–4 Μm were in similar shape with uniform diameter along its entire length with well faceted blunt ends. X-ray diffraction and transmission electron microscope analysis showed that the as-grown nanostructures were highly crystalline with wurtzite hexagonal structure having lattice constants of a=b=3.25 å and c=5.21 å. Room temperature photoluminescence (PL) measurements showed a weak near band-edge emission at 380 nm, but a strong green emission at 500–530 nm. A model for vapor-solid (VS) growth mechanism of ZnO nanowires was presented, in which nucleation of ZnO is crucial for the growth of the nanostructures.