有色金属工业含砷污染物处理研究进展

综述了有色金属工业砷污染物的来源及其无害化处理的方法,分析了包封固砷(水泥固化和玻璃固化)和矿物固砷(钙盐、铝盐、镁盐、硫化沉淀法)的优缺点和局限性,重点对将砷以臭葱石形式进行安全处理的合成方法和浸出稳定性的研究现状进行阐述。分析表明,晶态臭葱石合成是将砷以臭葱石形式进行安全处置的基础,稳定性是关键,进一步降低溶液过饱和度以实现大尺寸、高稳定性臭葱石的合成是发展方向。     

基于聚集诱导发光效应的高固低黏丙烯酸荧光树脂的制备及其性能研究

为了研制一种具有荧光功能特性的高固低黏羟基丙烯酸树脂。从聚集诱导发光效应（AIE）出发，将具有 AIE性质的二对丙烯酸四苯乙烯酯荧光分子通过自由基共聚连接于聚合物链段。由于聚合物链段对荧光分子化学键固定以及聚合物链的包裹束缚作用，导致荧光分子运动受限，从而实现涂层在紫外灯下荧光发光。通过荧光光谱的实时跟踪，探索高固低黏羟基丙烯酸树脂的合成以及固化规律。此外，由于聚合物链段对外界刺激具有实时响应性，从而间接影响了所连接的荧光分子的荧光发光行为。因此，文中也探索了涂层在外界温度与化学气体的影响下所发生的荧光变化的规律，以探索其在功能涂层中应用的可行性。     

Effects of graphite nano-flakes on thermal and microstructural properties of TiB2–SiC composites

In the last decades, the production of ultra-high temperature composites with improved thermo-mechanical properties has attracted much attention. This study focuses on the effect of graphite nano-flakes addition on the microstructure, densification, and thermal characteristics of TiB₂–25 vol% SiC composite. The samples were manufactured through spark plasma sintering process under the sintering conditions of 1800 °C/7 min/40 MPa. Scanning electron microscopy images demonstrated a homogenous dispersion of graphite flakes within the TiB₂–SiC composite causing a betterment in the densification process. The thermal diffusivity of the specimens was gained via the laser flash technique. The addition of graphite nano-flakes as a dopant in TiB₂–SiC did not change the thermal diffusivity. Consequently, the remarkable thermal conductivity of TiB₂–SiC remained intact. It seems that the finer grains and more interfaces obstruct the heat flow in TiB₂–SiC–graphite composites. Adding a small amount of graphite nano-flakes enhances the densification of the mentioned composite by preventing the grain growth.     

Semiconductor Fe-doped SrTiO3-δ perovskite electrolyte for low-temperature solid oxide fuel cell (LT-SOFC) operating below 520 °C

High-temperature operation of solid oxide fuel cells causes several degradation and material issues. Lowering the operating temperature results in reduced fuel cell performance primarily due to the limited ionic conductivity of the electrolyte. Here we introduce the Fe-doped SrTiO_3-δ (SFT) pure perovskite material as an electrolyte, which shows good ionic conduction even at lower temperatures, but has low electronic conduction avoiding short-circuiting. Fuel cell fabricated using this electrolyte exhibits a maximum power density of 540 mW/cm² at 520 °C with Ni-NCAL electrodes. It was found that the Fe-doping into the SrTiO_3-δ facilitates the creation of oxygen vacancies enhancing ionic conductivity and transport of oxygen ions. Such high performance can be attributed to band-bending at the interface of electrolyte/electrode, which suppresses electron flow, but enhances ionic flow.     

氮对镀锡钢板的强化作用

通过物理化学相分析研究了3种不同氮含量镀锡板中固溶氮、化合氮的含量,结合相关理论计算了镀锡板中氮的固溶强化和析出强化对强度的贡献。结果表明:随着总氮含量从0.0021%提高到0.0103%,钢中化合氮含量下降10.1%,但是AlN析出相中的氮的含量上升10.7%。氮在提高镀锡板强度方面发挥重要作用,钢中总氮含量提高0.0082%,其对屈服强度的贡献值提升约30 MPa。     

Thermally driven failure of Nd:YVO4 amplifier crystals

We report on an unusual failure pattern resulting from thermally driven fracture of laser amplifier single crystals. The pattern led to some confusion with regard to the point of initiation due to the coalescence of hackle lines to a region within the fracture surface, rather than the more common divergence of hackle away from the origin. The pattern leads to new fracture terms: Hackle node - the coalescence of hackle marks to a point of prior compression. The feature is produced as a thermally-generated, centrally-located compressive region transforms to tension thereby drawing crack propagation and hackle to the compressive region, forming an internal terminus. Hackle terminus – a hackle node formed by final crack propagation within the component. As part of the analysis, the fracture toughness and slow crack growth constants of neodymium doped, yttrium ortho-vanadate (Nd:YVO₄) were measured. Nd:YVO₄ exhibits slow crack growth and is very brittle with a fracture toughness of only 0.48 MPa√m.     

载荷对PTFE/AlSi10Mg复合材料摩擦磨损行为的影响

采用选区激光熔化(SLM)、浸渗和真空烧结工艺制备了以AlSi10Mg为基体的多孔骨架填充聚四氟乙烯(PTFE)的自润滑复合材料。采用往复式Bruker UMT-3摩擦试验机研究了速度为5mm/s、不同载荷下复合材料的摩擦磨损性能,并采用SEM、EDS等对其成分、结构以及摩擦学行为进行了研究。结果表明,复合材料的平均摩擦因数和磨损率随着载荷的增加呈现先增大后减小的趋势;复合材料的摩擦稳定性主要由存储在骨架中的PTFE决定。其摩擦机制主要是在载荷的作用下,当磨擦表面发生磨损时,骨架中的PTFE将磨屑捕获,形成完整的PTFE润滑层,并且发生膜的转移,从而增加了复合材料的摩擦学稳定性。     

Correlation between B value deviation and sintering temperature of perovskite solid solution materials

The effects of different sintering temperatures on the system of Ba_0.5Sr_0.5TiO₃–La_0.8Ca_0.2MnO₃ (BST-LCM) material were investigated by means of scanning electron microscopy, X-ray, resistance-temperature measurements, and X-ray photoelectron spectroscopy. X-ray diffraction and X-ray photoelectron spectroscopy confirm that BST-LCM is completely miscible and BST is the main phase, which under the premise of following the theory of small polaron conduction, titanium ions interact with manganese ions, which affects the electrical properties of the system of BST-LCM material. For the electrical properties of related, the LCM content is inversely proportional to the activation energy. Through the linear fitting of the experimental data, the empirical formula between the sintering temperature B value and the content of solid solution is obtained, and the approximate B value within a certain range can be preliminarily calculated.     

Phase diagram of the Li2SO4–Na2SO4 system

The thermal analysis and X-ray powder diffraction studies of the Li₂SO₄–Na₂SO₄ system, including the high-temperature X-ray diffraction technique, have elucidated four phases of variable composition: three solid solutions based on the α-Li₂SO₄, α-Na₂SO₄, and α-LiNaSO₄ high-temperature polymorphs, and a low-temperature β-LiNaSO₄ phase. α-Na₂SO₄-Base solid solution disintegrates into two phases via a monotectoid phase transformation. It is quite probable that the monotectoid process is related to the conversion of the second-order phase transition to the first-order phase transition.