水土环境中微生物胞外聚合物对污染物迁移和归宿影响的研究进展

在土壤和水环境中存在大量微生物,附着在其表面的胞外聚合物（extracellular polymeric substances,EPS）在重金属及有机污染物等的迁移和转化中发挥着重要作用。以保护水土环境、提升污染水土修复效率的科学和工程问题为目标,针对近年来国内外对EPS的组成和结构、影响微生物EPS分泌的因素、EPS的提取方法以及其生物降解性等方面的研究成果进行了综合评述,系统分析了EPS参与土壤和水环境中金属及有毒有机物质生物降解和去除的微观机制,进而针对现有研究中存在的问题,对EPS在土壤和水环境中的进一步研究空间,特别是如何提高理解EPS的生物和化学修复工程意义提出展望。     

水热合成二硫化钼纳米片及在锂离子电池中的应用(英文)

Molybdenum disulfide nanoflakes were synthesized by a simple hydrothermal process using sodium molybdate and thiourea as reactants at a relatively low temperature. X-ray diffraction(XRD) and transmission elec-tron microscopy(TEM) indicate that the samples have the structure of 2H-MoS2 and the morphology of nanoflakes with the average thickness around 5-10 nm. The results of electrochemical properties indicate that the morphology and size of MoS2 particles have effects on their capacity when they are used as the anode for lithium ion battery. The as-prepared MoS2 samples have high reversible discharge capacity up to 994.6 mA·h·g-1 for the MoS2-1 elec-trode and 930.1 mA·h·g-1 for the MoS2-2 electrode and show excellent cycling performances. The MoS2-1 electrode has a better cycling stability than the MoS2-2 electrode due to their difference in the uniformity of the samples.     

Hydrothermal treatment of metallic-monolith catalyst support with selfgrowing porous anodic-alumina film

Metallic-monolith catalyst support with self-growing porous anodic alumina(PAA) film was prepared by anodizing Al plate. The effect of hydrothermal treatment(HTT) on the crystalline state and textural properties of PAA film was investigated by XRD, BET, SEM and TG. The HTT treatment above 50 °C and the subsequent calcination above 300 °C could convert the amorphous skeleton alumina into γ-alumina and increase the specific surface area(SBET). However, SEM images showed the HTT modification was a non-uniform process along the thickness of PAA film. The promotion effect of HTT on SBETwas non-linear, and the slope of SBETgradually decreased with the HTT temperature or time increased. The limited HTT effect should be attributed to a changed pore structure caused by an unfavorable pore sealing limitation. Pore widening treatment(PWT) before HTT could break the pore sealing limitation, because of the reduced internal diffusion resistance of hydrothermal reaction. The synergistic combination of PWT and HTT developed a PAA support with a large SBETcomparable to commercial γ-alumina. In the catalytic combustion of toluene, the Pt-based catalyst prepared by using the PWT and HTT comodified PAA support gave higher Pt dispersion and more favorable catalytic activity than that treated by HTT alone. The presence of a bimodal pore structure was suggested to be a decisive reason.     

圆柱壳径向开孔接管结构的塑性分析

介绍了压力容器分析设计中塑性分析方法的有限元数值模型,对圆柱壳径向开孔接管结构进行了塑性分析,并将分析得到的塑性垮塌载荷与实验得到的爆破压力进行了对比,为压力容器塑性分析方法的工程应用提供一定的参考。     

阿司匹林的合成在有机化学实验教学中的思考题设计

阿司匹林的合成是有机化学实验教材中的经典有机合成实验之一,结合实验步骤的讲解,按照测试学生对实验原理的掌握程度、启发式向学生解释操作步骤并提示操作注意事项、理解操作步骤的设计原则、拓展学生知识面等教学目标设计不同类型思考题,有利于改善教学效果,引导学生养成勤于思考的习惯,并提高其创新能力。     

石墨烯基铁氧化物对水体中草甘膦的动态吸附性能及模型

采用热沉积法制备出石墨烯/四氧化三铁（RGO-Fe₃O₄）复合材料,针对草甘膦（GLY）污染水体,开展该吸附材料对GLY的动态柱实验,通过考察污染物浓度、pH、流速、柱高等因素对穿透过程的影响,研究复合材料对GLY的动态吸附性能,并结合扫描电子显微镜（SEM-EDS）、X射线光电子能谱仪（XPS）、全自动比表面和孔隙分析仪（BET）等表征手段和Thomas、Yoon-Nelson和Yan等吸附模型分析吸附机理。实验结果表明：随着柱高增加,穿透时间延长,吸附柱对GLY的吸附总量增大;随着GLY初始浓度的升高,穿透时间缩短,吸附柱对GLY的吸附总量增大;随着流速和pH的升高,穿透时间缩短,吸附柱对GLY的吸附总量减小。此外,Thomas、Yoon-Nelson和Yan模型拟合得到的R²均大于0.9,且理论单位吸附量均与实际值相差不大,即3种模型均可较好地描述石墨烯复合材料对GLY的动态吸附过程。本实验的研究对石墨烯材料的推广应用及实际GLY污染水体的修复具有重要意义。     

网络型机动车停车场控制管理系统的设计

所设计的网络型机动车停车场控制管理系统是以单片机为执行核心,以计算机软件为管理核心.通过计算机网络技术和RS485工业总线的应用,车场规模可以无限制扩展,管理者能够远程管理和监控停车场,使用者可以在非现场进行停车位的预定等便捷的操作.通过下位门禁控制机的信息存储构成对上位机数据库的备份,保证了系统的稳定无差错运行.     

大型空分装置配套水浴式汽化器的设计理念与结构优化

针对大型空分装置配套水浴式汽化器,从设计角度出发,以节能减排为目的,讨论如何从设计理念方面(包括传热模型、放热方式、准则数关联式的选取等)以及结构设计方面来进一步优化,使水浴式汽化器理论计算更有依据、结构设计更加合理,真正达到快速响应以及节能减排的目标。     

冷速对IN718凝固过程中偏析和Rayleigh数的影响

利用SEM和EDS研究了在冷速分别为1,3和6K·min^-1时高温合金IN718的凝固组织、液体中Nb和Mo含量变化,并计算了液体密度差和相对Rayleigh数与温度的关系.结果表明:由于偏析,液体中Nb、Mo含量和液体密度差随着温度的降低而增加;冷速越低,Nb、Mo偏析越严重,同温度下液体密度差越大.相对Rayleigh数的计算表明,不同冷速下相对Rayleigh数都在1330℃存在最大值,随着冷速降低,其值急剧增加,黑斑形成趋势增大,大铸锭中冷速低于1K·min^-1时会形成黑斑.