磁性金属有机框架材料制备及吸附性能研究

利用简单的溶剂热法合成了MIL-101（Fe）/CoFe₂O₄和MIL-101（Fe）/NiFe₂O₄磁性金属有机框架纳米复合材料。通过X射线衍射仪（XRD）、扫描电子显微镜（SEM）、振动磁强计（VSM）、热重分析仪（TGA）和紫外可见分光光度计（UV）等对复合材料的相结构、形貌、磁性能和吸附性能进行了研究。将磁性金属有机框架材料用于吸附污水中罗丹明B（RhB）,研究了罗丹明B初始质量浓度对复合材料吸附能力的影响。结果表明,制备的磁性金属有机框架复合材料的形貌均匀、结晶度高,具有高的饱和磁化强度。复合物具有金属有机框架材料和磁性材料的双重优点。MIL-101（Fe）/CoFe₂O₄对罗丹明B有较高的吸附能力（97.3 mg/g）。热力学研究发现吸附等温方程符合Langmuir模型,吸附动力学研究表明吸附机制与吸附质和吸附剂有关。磁性金属有机框架纳米复合材料作为污水处理剂将具有广阔的应用前景。     

微波辐射对球型Co2+印迹壳聚糖树脂吸附特性的影响及动力学研究

以Co2 和壳聚糖为原料,环氧氯丙烷和异丙醇为交联剂,在微波辐射下制备了球形Co2 印迹壳聚糖树脂.研究了微波辐射时间、温度等因素对该印迹树脂吸附的影响及其吸附动力学.结果表明,随着微波辐射时间的增加,制得的印迹CTS树脂的吸附量增大,辐射5 min时吸附量达到最高,5 min后随微波时间的延长吸附量反而减少.印迹CTS树脂的吸附符合二级吸附动力学方程:t/Q=0.0009 0.0024t.球形印迹壳聚糖树脂的吸附是以多分子层不均匀吸附模式为主,符合Freundlich方程.在30～90 ℃的温度范围内,树脂的吸附量随温度升高而增加,70 ℃时达到最大值,随后呈下降趋势.     

CO气氛中液相催化COS水解活性的研究

在鼓泡反应器中，采用液相催化剂，对高浓度CO气氛中高浓度COS的水解反应进行考察，研究催化剂浓度、气液体积比、温度的变化对COS水解转化率及催化体系稳定性的影响，得出最佳工艺条件，并对反应机理进行初步探讨。结果表明,COS水解转化率随气液体积比增大而降低，随催化剂浓度增大而升高；在常温、常压和气液体积比为150 h^－1的条件下，质量分数为10%的催化剂水溶液中COS的水解转化率可达100%，连续使用20 h转化率不变。     

On the involvement of radical oxygen species O− in catalytic oxidation of benzene to phenol by nitrous oxide

Catalytic oxidation of benzene to phenol by nitrous oxide over Fe-MFI zeolites was studied in relation to the active oxygen species taking part in the oxidation. A linear dependence of the reaction rate on the concentration of independently identified active sites generating O⁻ radicals (α sites) was obtained within a broad range of values. The dependence is interpreted as convincing evidence of the O⁻ involvement in the catalytic (not only stoichiometric) oxidation of benzene to phenol. This conclusion is of particular importance in connection with a long discussion in the literature on a possible role of O⁻ radicals in selective oxidation catalysis over V and Mo oxides. Reliable evidence of the catalytic role of O⁻ obtained with zeolites may renew general interest in the once-suggested but not recognized role of radical oxygen in oxidation over widely used metal oxide catalysts.     

Evaluation of amines for the selective catalytic reduction (SCR) of NOx from diesel engine exhaust

With a view to developing onboard generation of selective reductants for NO_x removal from diesel engine exhaust we compared the performance of a primary, secondary and tertiary amine to NH₃ using a typical mini core NH₃-SCR catalyst. Primary amines with short hydrocarbon chains, e.g. CH₃NH₂ (maximum NO_x conversion, 50%) approached the NO_x conversion obtained using NH₃ (maximum NO_x conversion, 70%). Increasing the amine to NO_x ratio greater than 1 results in NO_x conversions closer to those of NH₃ (maximum NO_x conversion increased to 60%). Secondary and tertiary amines had smaller NO_x conversions as a function of temperature and the drop in NO and NO_x conversion decreased with increasing amine hydrogen substitution. Also, the maximum NO_x conversion for each reductant tends to move to a lower temperature as the degree of substitution increases.Unlike NH₃, the amines can react in the gas phase at temperatures within the range of diesel engine exhaust. Due to this gas phase reactivity the NO_x conversions measured using the mini core SCR catalyst also contain a gas phase conversion component. Gas phase conversions were investigated by replacing the mini core SCR catalyst with an equivalent length of quartz beads. Subtraction of the two results highlighted the differences between the mini core catalytic and gas phase conversions measured in this manner over the temperature range investigated. These differential NO_x conversions for the three amines had maxima at about 375 °C.     

双向叶轮直驱式海浪发电装置设计与优化

为了降低海洋能源发电装置的发电成本、提升发电效率,研制了一种新型的双向叶轮直驱式海浪发电装置。采用经验算法和Fluent软件分别对装置的发电机、叶片、双向轴流泵和导流罩进行了设计优化。通过对安装20 W电机和200 W电机发电装置的水槽试验,分析了在不同工况和负载下,发电装置输出的直流电流值、直流电压值、发电功率以及获能效率。结果显示,波浪力能够直接驱动装置叶轮运转进行发电,不需经过中间环节转换,省去了二级发电损耗,在最低流速0.5 m/s的工况下装置能够自启动,而且水流的流向不影响装置的发电效率。从最终的获能效率可知,导流罩对于提升装置发电效率作用巨大。通过对此新型双向直驱式海浪发电装置的进一步研究表明,该发电装置尺寸及发电机功率是制约整个装置发电效率的关键,为下一步研制大型样机以及进行海试提供了依据。     

局部冲刷对部分埋入单桩水平承载性状的影响

为分析局部冲刷对部分埋入桩水平承载性状的影响,利用有限元软件ABAQUS模拟水平荷载作用下部分埋入单桩的受力。根据实际工况建立了部分埋入水平受荷桩的三维有限元计算模型,并将计算结果与现场试验结果进行对比,验证了所建模型的正确性。然后,通过算例分析了冲刷角度、深度、桩直径、桩顶约束条件和桩自由段长度对部分埋入桩水平承载性状的影响。分析结果表明:局部冲刷深度比冲刷角度对部分埋入桩的水平承载性状影响更大,局部冲刷对直径较大的桩体承载能力影响也更大,自由段长度的增大减小了桩体水平承载力,因此,在研究冲刷对桩基水平承载性状的影响时,应结合桩顶约束条件综合考虑。     

Continuous finite element schemes for a phase field model in two-layer fluid Bénard–Marangoni convection computations

In this article, we study a phase field model for a two-layer fluid where the temperature dependence of both the density (buoyancy forces) and the surface tension (Marangoni effects) is considered. The phase field model consisting of a modified Navier–Stokes equation, a Cahn–Hilliard phase field equation and an energy transport equation is derived through an energetic variational procedure. An appropriate variational form and a continuous finite element method are adopted to maintain the underlying energy law to its greatest extent. A few examples for Bénard–Marangoni convection in an Acetonitrile and n-Hexane two-layer fluid system heated from above will be computed to justify our phase field model and further show the good performance of our methods. In addition, an interesting experiment will be performed to show the competition between the Marangoni effects and the buoyancy forces.     

Effects of sulfate-reducing bacteria on the corrosion behavior of carbon steel

The influences of the growing process of sulfate-reducing bacteria (SRB) in seawater system on the medium state and corrosion behavior of carbon steel were studied by detecting solution state parameters and using corrosion electrochemical methods. The growing process of SRB in the seawater shows the three stages of growing, death and residual phases. The solution state parameters of the concentration of sulfide, the pH value and the redox potential changed during the three stages of the SRB growing process. And the corrosion rate of D36 carbon steel was accelerated during the growing phase and stable during the death and residual phases. The results indicate that the medium state and the corrosion rate of the steel do not depend on the number of active SRB, but depend on the accumulation of the metabolism products of SRB.     

Adaptive Neural Network Finite-Time Control for Uncertain Robotic Manipulators

An adaptive neural network finite-time controller (NNFTC) for a class of uncertain nonlinear systems is proposed by using the backstepping method, which employs an adaptive neural network (NN) system to approximate the structure uncertainties and uses a variable structure term to compensate the approximation errors, thus improving the robustness of the system to external disturbances. The controller is then applied to uncertain robotic manipulators, with a control objective of driving the system state to the original equilibrium point. It is proved that the closed-loop system is finite-time stable. Moreover, simulated and experimental results indicate that the proposed NNFTC is effective and robust.