Facile synthesis of ordered mesoporous carbons with high thermal stability by self-assembly of resorcinol-formaldehyde and block copolymers under highly acidic conditions

The effect of phenols reactivity with formaldehyde on the formation of ordered mesoporous carbons has been investigated. A strategy to accelerate the polymerization of phenolic resins by using strongly acidic conditions is proposed. The self-assembly of resorcinol-formaldehyde and block copolymers (e.g., F127) under highly acidic concentrations (e.g., 1.5 M HCl) is probably driven by the I+X-S+ mechanism and hydrogen bonding and affords a highly reproducible approach for synthesis of ordered mesoporous carbons. The synthesis can be readily scaled up with no change in sample quality. The carbon material obtained (denoted as C-ORNL-1) exhibits highly ordered hexagonal mesostructure, with a typical BET surface area of approximately 600 m2/g, pore size of 6.3 nm, and pore volume of approximately 0.60 cm3/g. One of the unique structural features of C-ORNL-1 is its high thermal stability; it can be graphitized at 2600 degrees C while considerable mesoporosity is maintained.     

An Air‐Stable Na3SbS4 Superionic Conductor Prepared by a Rapid and Economic Synthetic Procedure

All‐solid‐state sodium batteries, using solid electrolyte and abundant sodium resources, show great promise for safe, low‐cost, and large‐scale energy storage applications. The exploration of novel solid electrolytes is critical for the room temperature operation of all‐solid‐state Na batteries. An ideal solid electrolyte must have high ionic conductivity, hold outstanding chemical and electrochemical stability, and employ low‐cost synthetic methods. Achieving the combination of these properties is a grand challenge for the synthesis of sulfide‐based solid electrolytes. Design of the solid electrolyte Na₃SbS₄ is described, realizing excellent air stability and an economic synthesis based on hard and soft acid and base (HSAB) theory. This new solid electrolyte also exhibits a remarkably high ionic conductivity of 1 mS cm^?1 at 25 °C and ideal compatibility with a metallic sodium anode.     

回旋行波管动力学分析及数值计算

 以小回旋电子注、均匀截面光滑壁圆柱波导为例,对回旋行波管动力学色散方程作了解析分析和讨论;数值计算和分析了注波互作用耦合系数与电子注参数的相互关系,为优化选择电子注参数,提高注波互作用效率获得了依据。     

环形孔径高斯光束的远场特性

 讨论了环形孔径高斯光束的远场光斑能量分布,并给出了拟合表达式。首先推导了光束没有抖动时远场光斑的光能分布表达式,然后研究了各种不同中心遮拦和不同光束截断比, 在有以及没有激光束抖动的情况下,对高斯光束的远场环围能量的分布变化的影响。     

薄壁玻璃微球壳的热扩散充气

 导出了热扩散一步充气法和分步充气法充气时,薄壁玻璃微球壳的内压变化,及其在空气中的气体渗漏速率和保气半寿命的表达式,提出了确定分步充气过程操作参数的约束条件。D₂气体通过薄壁玻璃微球壳的扩散速率与分步法充D₂气体时其内压的实验测量值与计算值相符合。     

回旋管双阳极磁控注入电子枪的设计

根据回旋管对电子枪的要求,设计了该双阳极磁控注入电子枪。给出了电极形状、电子轨迹与电子注参量。这种电子枪具有速度零散小、层流性较好、体积小等特点。     

行波管三维非线性计算机模拟的改进

采用宏粒子模型计算空间电荷力,导出行波管三维大讯号工作方程组,开发出ＶｉｓｕａｌＣ＋＋数值分析软件。随后进行计算机模拟,提出将三维空间电荷力处理为二维,大大节省了计算时间,数值结果与三维计算吻合很好。     

电子束在等离子体微波器件中的脉动

 对填充等离子体漂移空间小脉动电子束进行了近似分析,对大脉动电子束进行了较精确的计算,结果表明虽然α区和β区束的脉动性能各不相同,但幅度和波长均受限于电子入射的初始条件和等离子体参数,当其它条件给定后存在一最佳等离子体填充密度。     

偶氮硝羧速差动力学同时测定钙和锶的研究

基于钙、锶与显色剂偶氮硝羧在非离子表面活性剂Triton X-100存在下,于pH值2.9的邻苯二甲酸氢钾-盐酸缓冲溶液中显色反应速率差异,用速差动力学比例方程法同时吸光光度测定钙和锶.其最大吸收波长为708nm,表观摩尔吸光系数钙、锶分别为2.0×10~4和4.2×10~4L·mol~(-1)·cm~(-1),钙量在0～80μg/25ml,锶量在0～70μg/25ml范围内服从比耳定律.该法已用于发祥和纯净水中钙和锶的同时测定,结果较好.