垃圾填埋场中水泥土屏障对Cu2+的阻滞性能

通过室内模型试验,研究了不同水泥掺量的水泥土防渗屏障和上海老港填埋场的膨润土砂水泥(塑性混凝土)防渗屏障对Cu~(2+)的阻滞效果,并应用数值模拟的方法对Cu~(2+)在防渗屏障中的有效扩散系数进行求解.研究结果表明,随着水泥掺量和屏障厚度的增加,水泥土屏障对金属离子的阻滞效果会逐步提升;Cu~(2+)在水泥土中的有效扩散系数(1×10~(-7)~2.5×10~(-7) cm~2·s~(-1))是在土中的有效扩散系数(9.53×10~(-6)~1.14×10~(-5) cm~2·s~(-1))的1/35~1/100;上海老港填埋场中的塑性混凝土防渗屏障对Cu~(2+)有较好的阻滞效果.     

纳米Fe/Cu双金属的制备及其对水中亚甲基蓝的去除

利用液相还原法制备了纳米Fe/Cu颗粒,考察了其对水中亚甲基蓝的去除性能,研究了不同pH、亚甲基蓝初始浓度和反应时间对去除效果的影响.结果表明,酸性条件下Fe/Cu纳米双金属对亚甲基蓝去除效果良好,且在45min时反应达到平衡,对亚甲基蓝的去除过程符合准一级动力学方程和Langmuir吸附等温模型.     

Microstructure and mechanical properties of SiC-particle-strengthening tri-metal Al/Cu/Ni composite produced by accumulative roll bonding process

In this study, a multilayer Al/Ni/Cu composite reinforced with SiC particles was produced using an accumulative roll bonding (ARB) process with different cycles. The microstructure and mechanical properties of this composite were investigated using optical and scanning microscopy and hardness and tensile testing. The results show that by increasing the applied strain, the Al/Ni/Cu multilayer composite converted from layer features to near a particle-strengthening characteristic. After the fifth ARB cycle, a composite with a uniform distribution of reinforcements (Cu, Ni, and SiC) was fabricated. The tensile strength of the composite increased from the initial sandwich structure to the first ARB cycle and then decreased from the first to the third ARB cycle. Upon reaching five ARB cycles, the tensile strength of the composite increased again. The variation in the elongation of the composite exhibited a tendency similar to that of its tensile strength. It is observed that with increasing strain, the microhardness values of the Al, Cu, and Ni layers increased, and that the dominant fracture mechanisms of Al and Cu were dimple formation and ductile fracture. In contrast, brittle fracture in specific plains was the main characteristic of Ni fractures.     

Solid-phase synthesis of Cu<Subscript>2</Subscript>MoS<Subscript>4</Subscript> nanoparticles for degradation of methyl blue under a halogen-tungsten lamp

The Cu₂MoS₄ nanoparticles were prepared using a relatively simple and convenient solid-phase process, which was applied for the first time. The crystalline structure, morphology, and optical properties of Cu₂MoS₄ nanoparticles were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and UV-vis spectrophotometry. Cu₂MoS₄ nanoparticles having a band gap of 1.66 eV exhibits good photocatalytic activity in the degradation of methylene blue, which indicates that this simple process may be critical to facilitate the cheap production of photocatalysts.     

Cu含量对2A14铝合金显微组织和腐蚀性能的影响

为了提升2A14铝合金耐局部腐蚀性能,采用扫描电镜(SEM)、点蚀测试、循环阳极极化曲线(Tafel)和电化学阻抗谱(EIS)等分析测试方法,研究了Cu含量对2A14铝合金锻件显微组织和腐蚀性能的影响.结果表明:随着Cu含量降低,诱导点蚀的Al2Cu和AlCuMgSi残余结晶相体积分数减小,点蚀坑密度显著降低,合金抗点蚀性能和电化学腐蚀性能大幅提高.     

δ掺杂对磁纳米结构中电子输运性质的影响

建立铁磁条调制下含有δ掺杂的磁纳米结构模型,计算不同δ掺杂位置及高度时电子的透射几率及自旋极化率,重点研究了该纳米结构中电子的自旋输运性质。结果表明,该磁纳米结构中可实现较显著的自旋极化效应,且δ掺杂的位置及高度均会对其中的电子输运性质产生影响。因此,理论上可以通过控制δ掺杂的位置及高度来获得实际需要的自旋极化强度,有助于新型自旋电子学器件的开发。     

La掺杂对SrTiO_3纳米颗粒光催化性能的影响

采用高温固相反应法,向SrTiO_3中掺杂不同含量La制备光催化剂,通过XRD、SEM、UV-Vis等手段对其结构和形貌进行表征,并以罗丹明B(RhB)为模拟污染物,研究掺杂不同含量La所制催化剂对RhB的光催化降解能力的影响,从而评价所制催化剂的光催化性能。结果表明,随着掺La含量的增加,所制催化剂的晶体结构从SrTiO_3的立方晶系逐步向La_2Ti_2O_3的单斜晶系转变;La掺杂使得所制催化剂的禁带宽度减小、对紫外光的吸收阈值增大,使其光催化性能得到显著提升;掺La含量越高,所制催化剂的光催化性能越好。     

钴掺杂对二氧化钛晶粒尺寸及相变的影响

通过溶胶凝胶法制备了纯Ti O_2与不同Co浓度掺杂的Ti O_2纳米粉体,并对样品进行了450、550、650℃保温2 h的热处理.采用X射线衍射仪对制得的纳米粉体进行了晶体结构表征,研究了热处理温度以及Co掺杂浓度对Ti O_2晶粒尺寸以及锐钛矿金红石相变的影响.结果表明:纯Ti O_2与Co-Ti O_2在450℃时为单一的锐钛矿;550℃时,纯Ti O_2有微量金红石生成,Co-Ti O_2仍然全部为锐钛矿;650℃时纯Ti O_2大部分转变为金红石,当Co掺杂量较低时,Co能促进锐钛矿相向金红石相的转变,而当掺杂浓度为8%时,Co抑制锐钛矿相向金红石相的转变;热处理温度升高以及Co掺杂浓度增加有利于Co Ti O_3相的生成,相同温度下,Co掺杂后Ti O_2晶粒尺寸减小.     

铕掺杂ZnO纳米棒的生长及其光电性能的研究

利用水热法在硼掺杂金刚石膜上生长铕(Eu)掺杂Zn O纳米棒(Zn O:Eu),其形貌与Eu的掺杂量密切相关。掺杂0.01 mol/L Eu时对Zn O纳米棒生长影响较小,随着掺杂浓度的增加,Zn O纳米棒顶部出现"尖端聚集现象",这种聚集现象是和纳米棒制备过程中电荷积累相关的,稀土元素能提供更多的电荷,使Zn O纳米棒顶端产生强的局部电场,相近纳米棒尖端会聚集一起。制作了以p型金刚石为衬底生长的Zn O:Eu异质结,并对其电学性能深入研究,实验结果表明该异质结对整流特性有良好反应。     

钒掺杂SrTiO_3光催化剂的制备及性能研究

用溶胶-凝胶法制备不同质量分数V掺杂的SrTiO_3光催化剂粉体(V-SrTiO_3),通过X-射线衍射(XRD)、扫描电子显微镜(SEM)、激光粒度仪对其结构和形貌进行表征,用亚甲基蓝(MB)催化降解实验评价其光催化活性.结果表明,V掺杂后SrTiO_3仍然保持钙钛矿结构,V5+进入晶格对Sr2+进行了替位掺杂,晶格常数变小;热处理温度升高,样品发生热团聚;V掺杂后SrTiO_3的催化活性得到了明显的提高,并随着热处理温度的升高,光催化降解率先增加后降低;当n(V)∶n(Ti)=1.5∶100,热处理温度为800℃下制备的样品催化活性高达90.5%.