转变实验理念,全面提升化工原理实验教学质量的研究

实践教学是培养学生解决实际问题能力的重要环节。化工原理实验又化工厂单元操作的缩影。我们引导学生从无机化学、有机化学实验的瓶瓶罐罐进入管路系统的操作;从老师讲解实验原理、操作步骤到学生自己摸流程,直至开停车,再用理论知识理解和解释所做实验的目的;从直接输入数据得到结果到自己用Excel编程进行数据处理及绘图操作;教改使学生花在实验上的时间多了。大部分学生掌握了用Excel处理数据及绘图的方法,并增强了团队的协作精神。     

Chemical looping gasification of cotton stalk with bimetallic Cu/Ni/olivine as oxygen carrier

Bimetallic Cu/Ni/olivine oxygen carriers (OCs) were prepared using olivine as support material for chemical looping gasification (CLG). The cyclic redox behaviors and oxygen carrying capacity (R_o) of OCs were evaluated by thermo-gravimetric analysis. The effect of Cu/Ni ratio, gasification temperature, steam to biomass ratio (S/B), oxygen carrier to biomass ratio (OC/B) on CLG of cotton stalk has been studied in a fixed bed. The OCs characterized using BET surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), temperature-programmed reduction (TPR) to investigate the physicochemical property of OCs during CLG. Result shows that the sintering problem of OC was progressively alleviated with the increasing Cu/Ni ratio. The olivine behaves as suitable OC support with oxygen carrying capacity of 1.07%. The redox reactivity of all of the OCs kept well during multiple redox cycles. The R_o of OCs progressively increased with the Cu/Ni ratio. By comparing the product gas concentration, carbon conversion, H₂ + CO yield and gas yield over the invested OCs, the Cu9/Ni6/O was found to demonstrate better comprehensive CLG performance due to the synergistic effect of Cu and Ni. The maximum gas yield, H₂ + CO yield and carbon conversion with Cu9/Ni6/O can be obtained at the S/B of 0.8 and OC/B of 2. Compared to theoretical value, 65% of lattice oxygen has been supplied by Cu9/Ni6/O during actual CLG process. The OC displayed better reactivity due to basic crystalline phase being preserved well during multiple CLG cycles.     

Preparation of rGO/AgCl QDs and its enhanced photoelectrocatalytic performance for the degradation of Tetracycline

A novel rGO/AgCl QDs composites have been obtained by an ultrasonic-assisted method for the first time. Photoelectrocatalytic (PEC) performances of the obtained samples were studied by the degradation of 20 mg/L Tetracycline (TC) under visible light irradiation with an applied bias potential of 1.5 V (vs Ag/AgCl). Degradation of TC by different processes including Photocatalysis (PC), Electrocatalysis (EC), and PEC was compared, and the effect of different bias potential on the PEC degradation of TC was discussed. Results showed that rGO/AgCl QDs composites had displayed superior PEC activity than that of pristine AgCl QDs with degrading 85.2% of TC during 120 minutes, which was about 1.5 times higher than that of AgCl QDs (33%). Besides, compared to PC and EC removal of TC, PEC process showed the highest degradation efficiency of TC (85.2%) by rGO/AgCl QDs, which was about three times and one time higher than that of PC (39.18%) and EC (20.73%) system, respectively. Moreover, the reusibility and stability of the samples were tested by five times cycling tests, and results demonstrated that the stability of bare AgCl QDs was improved after the introduction of rGO. The enhanced PEC activity and stability of the samples could be attributed to the intimate contact between rGO and AgCl QDs and external electric field, which had benefitted the formation of more active sites and accelerated electron-hole separation.     

Sonochemical preparation and photocatalytic properties of CdS QDs /Bi2WO6 3D heterojunction

Hierarchical CdS quantum dots (QDs)/ Bi₂WO₆ three-dimensional (3D) heterojunction photocatalyst was successfully synthesized by a facile green ultrasonic method for the first time. Photocatalytic activities under visible light irradiation were tested by the degradation of Rhodamine B (RhB) and tetracycline hydrochloride (TC), and the reduction of Cr(VI) in aqueous solution. As compared to pure CdS and Bi₂WO₆, CdS QDs/ Bi₂WO₆ heterojunctions manifested a significantly enhanced photocatalytic activity for these treatments. When the effect of the mass ratio of CdS QDs to Bi₂WO₆ was investigated, 3% CdS QDs/ Bi₂WO₆ heterojunction showed the highest photocatalytic efficiency: the efficiency for RhB degradation was 94.5% for 30?min and this value was about 6 times and 1.5 times higher than those of pure Bi₂WO₆ and CdS QDs. This enhancement was majorly accredited to the synergetic effect between Bi₂WO₆ and CdS QDs, which included intimate contact and matched band gap potentials between 0D CdS QDs and 3D Bi₂WO₆, which contributed to the efficient electron-hole separation and fast transfer of charge carriers between CdS QDs and Bi₂WO₆. A possible Z-scheme photocatalytic mechanism was proposed, in which the sample was provided with the efficient charge transfer pathway and was endowed with excellent oxidation and reduction ability.     

基于边缘对应的三维颅骨自动非刚性配准方法

针对三维颅骨模型在初始姿态相差较大以及存在较多缺失情况下自动配准困难的问题,提出一种基于边缘对应的三维颅骨非刚性自动配准方法。首先对待配准三维颅骨进行边缘提取,获得所有孔洞的边缘;然后根据边缘长度以及边缘间最短距离自动识别边缘类型,建立待配准颅骨和参考颅骨在边缘上的对应;之后对待配准颅骨的初始位置和姿态进行调整,实现粗配准;最后通过两次一致点漂移（CPD）算法逐步实现两个颅骨从边缘区域至所有区域的精确配准。实验结果表明,与常用的基于迭代最近点（ICP）和薄板样条函数（TPS）相结合的三维颅骨自动配准方法相比,该方法对姿态、位置、分辨率以及缺损具有更强的鲁棒性,并且配准效率更高。     

锂云母浮选捕收剂研究现状及展望

随着我国锂云母资源被大量开发,贫细杂问题愈发突出,高效回收锂云母已成为选矿领域的研究热点。本文综述了锂云母浮选存在的问题和捕收剂研究现状,提出了应加大对捕收剂作用机理研究和新型捕收剂研发工作。     

高效液相色谱法测定野蔷薇果中Vc含量的研究

建立一种高效液相色谱法测定野蔷薇中Vc含量的新方法.采用Diamonsil 5μ C18反相柱(200mm×4.6mm×5μm)分离;流动相为甲醇-0.01%磷酸水溶液(3:7,体积分数);柱温25℃;流速1.0mL/min;二级管陈列检测器,检测波长254nm.Vc在浓度为20mg/L～1500mg/L范围内呈良好的线性关系,线性回归方程为y=17.136x 120.8,相关系数为0.9992,方法回收率为97%～101%相对标准偏差小于3%.该方法简便、快速、准确、适合于测定其它水果和蔬菜中Vc的含量.     

浅谈化工原理授课中如何引入生活现象及基本知识

化工原理课程是化工、制药、环境等专业的重要专业基础课。如何将复杂问题进行简化是授课的艺术所在。文章介绍了通过引入生活中常见的现象将复杂问题简单化的方法,以期加强学生对主要化工单元操作的基本原理的理解。教学实践表明,这种方法可以加深学生对化工原理课程知识的理解,显著提高学生的学习兴趣。     

野蔷薇果皮色素的提取和稳定性研究

采用正交试验对野蔷薇果皮色素的最佳提取条件进行了研究,并探讨该色素的稳定性.结果表明:在60%下采用60%乙醇,以1:6物料比,pH6.0,浸提时间4h条件下色素产率最高;该色素属水溶性色素,耐光性、耐高温性好,在酸性介质以及常用食品添加剂等条件下有较好的稳定性,可作为食品饮料、医药等行业的天然植物色素广泛使用.     

油酸钠浮选体系下 STPP 对菱锰矿中方解石的抑制机理研究

由于菱锰矿与方解石具有相似的晶体结构,表面性质十分接近,因此菱锰矿与方解石的浮选分离一直是选矿领域的难题。 对油酸钠(NaOL)体系下三聚磷酸钠(STPP)作为抑制剂对菱锰矿和方解石选择性抑制的性能进行了探讨,重点讨论了 STPP 对方解石的抑制机理。 单矿物浮选试验结果表明,在 NaOL 体系下 STPP 对方解石具有强烈的抑制作用,而对菱锰矿浮选的影响较小。 Zeta 电位和傅里叶红外光谱分析表明,NaOL 在方解石表面的吸附可受 STPP 影响,而在菱锰矿表面的吸附能力几乎不变。 基于 X 射线光电子能谱的分析表明,STPP 与菱锰矿之间存在物理吸附关系,而与方解石之间为化学吸附关系。 大量的 STPP 与方解石表面的 Ca 位点产生螯合作用以覆盖在其表面是 STPP 能选择性优先抑制方解石的主要原因。 因此在 NaOL 体系下进行菱锰矿浮选,STPP 是方解石的有效抑制剂,可实现对方解石的高效抑制作用。