湿法冶金结合喷雾干燥-热解工艺纯化和控制钨颗粒

钨因其独特的物理化学性能而被广泛的应用于半导体和高温材料。本文依次采用离子交换、溶剂萃取、重结晶、喷雾干燥和煅烧还原的方法对钨酸铵进行处理,成功制备出高纯、分散性好的微米级球形钨粉。其中,利用湿法冶金去除原料中的杂质金属,喷雾干燥和煅烧还原过程控制最终钨粉形貌结构和粒径分布。本文研究了喷雾干燥过程中溶液浓度对雾化粉末形貌的影响规律,并揭示了雾化粉末分解还原过程中的机理。该方法制备出的钨粉纯度高于99.995wt%,平均尺寸约为1.5um。本研究中的湿法冶金和粉末技术可用于合成其他具有高性能要求的金属粉末。     

数字聚焦微电阻率测井仪设计

提出了一种采用数字聚焦方法的微电阻率测井仪器设计方案，其主要特点利用DSP集成芯片的数字信号处理优势，实现仪器的控制与测量，并通过软件滤波和聚焦处理获得视电阻率。该设计用超大规模集成电路DSP及软件处理取代了老式微球形聚焦测井仪器复杂的硬件监控、反馈、检波和测量线路，提高了仪器的可靠性和测量精度。对仪器原理进行了较详细的说明，在DSP技术应用于测井井下仪器方面做了有益的探索。     

新型Ba-GTP微球示踪剂的应用及资料效果评价

介绍了新型同位素载体的研制及测井实例;对比了新旧同位素载体的优缺点;证明了在三次加密井网和"三低"油田低注水井注水剖面测井中使用新型同位素载体的可靠性.     

煤矿液黏软启动装置摩擦片摩擦机理分析

从几种经典摩擦机理入手,分析了各种单一摩擦机理与生产实践中存在的各种矛盾及其原因,并得出结论:摩擦片之间的摩擦力主要是由犁沟效应和液体摩擦引起,建立了犁沟效应的微球冠凸体模型,得到了摩擦片之间摩擦力的计算公式。     

球状CeO_2的工艺优化及性能表征

以六水合硝酸铈、葡萄糖、丙烯酰胺为原料,氨水为沉淀剂,采用水热法制备了CeO_2,并利用正交试验考察了水热反应温度、反应时间及热处理时的焙烧温度对CeO_2比表面积大小和形貌的影响。运用SEM、XRD和BET等手段对样品进行表征。结果表明,水热反应温度是决定CeO_2比表面积大小的最重要因素,并且形貌越接近球形,其比表面积越大。最佳的制备条件是焙烧温度400℃、水热反应温度180℃、反应时间48h。     

热熔回流工艺参数对微球形结构高度影响的仿真研究

应用Marc软件仿真光刻胶熔融变形过程,研究热熔回流工艺参数对尺寸规格D×h为Ф500μm×66μm的微圆柱光刻胶熔融后微球形结构高度的影响.对仿真结果进行正交实验法分析,得出最佳工艺参数组合;对仿真结果进行单因素实验法分析,研究不同工艺参数对微球形结构高度的影响规律.结果表明,最佳工艺参数组合:加热速率1℃/8,加热温度110℃,保温时间45 min;工艺参数对微球形结构高度的影响顺序为:保温时间>加热速率>加热温度.     

Facile synthesis of micro-spherical LiMn0.7Fe0.3PO4/C cathodes with advanced cycle life and rate performance for lithium-ion battery

A series of micro-spherical LiMn_0.7Fe_0.3PO₄/C (LMFP) cathode materials are synthesized via co-precipitation method combining spray drying and solid-state reaction. All as-prepared materials are well-characterized to determine their crystal structure, morphology and electrochemical performance. All as-obtained LMFP materials correspond to orthorhombic olivine structure with Pbnm space group and show uniform porous spherical structure with an average particle size of 3 µm and a carbon coating layer of about 3 nm. In particular, the resulting LMFP material prepared at 600 °C exhibits a high discharge capacity of 160 mAh g⁻¹ at 0.1 C. Even at a high rate of 10 C, it can still deliver 133 mAh g⁻¹ and maintain capacity retention of 84.9% after 200 cycles. The excellent electrochemical performance is ascribed to the synergetic effect of porous micro-spherical structure and uniform carbon coating layer.     

微球聚焦有限元数值计算中的预处理技术研究

针对微球聚焦测井仪器的测井预处理响应,在分析有限元数值计算方法的基础上,研究了自动网格剖分和自动节点编号预处理技术.在1/2空间三角形网格剖分中,采用极板对称轴对称分割的方法,提高了计算电位的对称性和计算精度.在网格自动编号中,提出了根据电极结构对求解区域分块的思想,保证电极的编号连续,满足有限元数值计算中等位面处理的要求.通过计算仪器常数、无侵和有侵地层模型验证了所设计预处理程序的有效性.     

Novel micro-spherical Si3N4 nanowire sponges from carbon-doped silica sol foams via reverse templating method

A novel kind of nanowire sponges, namely Si₃N₄ nanowire-weaving microspheres, synthesized from a simple, convenient, high-efficient approach are proposed here. As the reverse template, three-dimensional foam skeleton structure with uniform pores and ultrathin pore walls is constructed via the effective particle-stabilized foam method, where the silica sol and carbon black are chosen as the raw materials, providing the sufficient space for the growth of nanowires during the carbothermal reduction reaction process. The formation mechanism of this novel sponge is studied via multiple characterization methods. Si₃N₄ nanowires formed microspheres possess uniform and curving morphology due to the stable environment for growing via vapor–solid mechanism, leading to the relatively high specific surface area of 86.77 m²/g. Owing to in-situ oxidation process, micro-spherical SiO₂ nanowire sponges with similar morphology are synthesized, which present diameter in range of 20-40 nm and specific surface area of 50.47 m²/g. This work provides insights for the design of high-performance nanowire sponges with promising applications in the filtration, thermal insulators, and catalyst supports fields.