碳气凝胶薄片的制备及表面密度致密层去除工艺

研究了不同密度和厚度的碳气凝胶薄片的制备及其表面致密层去除工艺。在以间苯二酚、甲醛为原料制备有机及碳气凝胶块体材料的基础上，结合自制活动式微模具成型工艺，制备了厚度在80~350 μm，密度在50~600 mg·cm-3范围内变化的碳气凝胶薄片。采用场发射扫描电镜、X射线相衬成像和表面轮廓仪-台阶仪等手段对其表面和内部微观结构进行了表征。测试结果表明，碳气凝胶薄片与块体的内部结构相同，但薄片表面存在一层和内部结构截然不同的致密层。采用不同粗糙程度的材料对薄片进行了表面微处理，成功去除该致密“皮”层。

Rapid growth of large size KDP crystal by temperature reduction method

Potassium dihydrogen phosphate (KDP) and its deuterated analog are the crystals primarily selected for Pockel’s cells or frequency conversion plates in inertial confinement fusion systems. Crystals rapidly grown from point seed by temperature reduction method are presented. The growth of large size crystals including the designation of big vessel, crystal holder and seed-planting under over-heating systems are introduced. Crystals with size up to 50 cm×50 cm×41 cm were obtained successfully. It is shown that crystals grown at rapid growth rate,15 mm/day the average, possess the optimal transmission properties as those grown by conventional method. The content of impurity ions, such as Fe³⁺, Cr³⁺, Al³⁺ that affect the prismatic faces of KDP are determined