传统激光熔覆增材制造方法一般采用等线宽扫描, 难以实现单道连续变宽成形。设计了变壁厚扭曲叶片模型, 利用光内送粉喷头直接变焦法变化光斑直径, 采用层高控制系统测量不同宽度处的实际堆积高度。设计PI控制器, 通过变化扫描速度, 控制不同宽度处的熔道堆积层高一致, 保证成形精度。通过连续变焦与闭环控制算法, 实现了变壁厚扭曲叶片激光熔覆连续变宽扫描成形。结果表明: 扭曲叶片在壁厚2.52~6.18 mm范围内均匀变化, 最大壁厚误差为-0.58 mm; 各段高度大致相同, 最大高度误差为-0.22 mm; 不同壁厚处的显微组织较为致密均匀。

为了实现对聚对苯二甲酸乙二醇酯（PET)瓶胚壁厚实时、高效、高精度的测量, 采用理论仿真结合实验验证的方法, 以标称3.5mm厚型的PET瓶胚为例给出设计实例, 建立了PET瓶胚壁厚测量的光学模型, 根据光线追迹原理分析验证反射式光纤位移传感器在测量PET瓶胚壁厚中应用的可行性, 并利用LIGHTTOOLS软件进行仿真模拟, 最终设计出一种基于反射式光纤位移传感器对PET瓶胚壁厚实时测量的装置, 并进行了实验验证。结果表明, 实验装置的测量量程为3.20mm~3.80mm, 线性度为15.8%, 灵敏度为0.8448mV/μm, 该装置相比传统测量效率提高了30%以上。这对提高实际检测效率和精度具有参考应用价值。

Hollow poly(alpha-methylstyrene) (PAMS) shows application in inertial confinement fusion experiments as the degradable mandrels of glow plasma polymer shells. However, the molecular weight of PAMS has great influence on the quality of mandrels. In this work, this influence was systematically studied using several PAMS samples with different molecular weights. For PAMS shells with 900 μm inner diameter and different wall thickness, when the molecular weight of PAMS is in the range of 300-500 kg·mol^-1, perfect sphericity and good wall thickness uniformity can be obtained. In contrast, when increasing molecular weight to 800 kg·mol ^-1, the sphericity and the wall thickness uniformity become worse. Moreover, compared with the wall uniformity, the sphericity of PAMS shells was much less sensitive to the molecular weight. The results also showed that the stability of W1/O compound droplets of PAMS shells were less affected by the molecular weight. It was revealed that the wall uniformity and the sphericity of the PAMS shells were associated with the diffusion rates of fluorobenzene (FB).

为了同时同位测量石英管的外径和壁厚, 建立了激光透射成像系统, 对系统测量原理进行研究。基于几何光学和菲涅尔公式, 分别导出平行光垂直照射石英管后的透射光线偏向角、相对光强与入射光线离轴距离之间的关系; 通过数值计算, 分析了偏向角、相对透射光强随入射光线离轴距离的变化特点; 针对物方远心光路, 分析了光阑对偏向角和相对光强的限制; 基于CCD成像原理, 通过引入标定系数和补偿因子, 导出石英管外径与壁厚的计算公式。实验结果表明: 外径绝对误差和相对误差的平均值分别为0.119mm和0.91%, 壁厚绝对误差和相对误差的平均值分别为0.153mm和6%。

Polymer shells with high sphericity and uniform wall thickness are always needed in the inertial confined fusion (ICF) experiments. Driven by the need to control the shape of water-in-oil (W1/O) compound droplets, the effects of the density matching level, the interfacial tension and the rotation speed of the continuing fluid field on the sphericity and wall thickness uniformity of the resulting polymer shells were investigated and the spherical and concentric mechanisms were also discussed. The centering of W1/O compound droplets, the location and movement of W1/O compound droplets in the external phase (W2) were significantly affected by the density matching level of the key stage and the rotation speed of the continuing fluid field. Therefore, by optimizing the density matching level and rotation speed, the batch yield of polystyrene (PS) shells with high sphericity and uniform wall thickness increased. Moreover, the sphericity also increased by raising the oil/water (O/W2) interfacial tension, which drove a droplet to be spherical. The experimental results show that the spherical driving force is from the interfacial tension affected by the two relative phases, while the concentric driving force, as a resultant force, is not only affected by the three phases, but also by the continuing fluid field. The understanding of spherical and concentric mechanism can provide some guidance for preparing polymer shells with high sphericity and uniform wall thickness.Physics for financial support (2014B0302052) and National Natural Science Foundation of China (U1530260).

采用化学气相沉积-氧化烧结法，在不同工作压强条件下，制备了惯性约束聚变靶用空心玻璃微球（HGM）。利用扫描电子显微镜、原子力显微镜、VMR显微镜系统和能谱仪对HGM的表面形貌、球形度、壁厚均匀性以及成分进行了表征。分析了工作压强对HGM表面形貌、球形度、壁厚均匀性和成分的影响以及相互关系。研究表明：HGM的表面形貌随工作压强的增大而变得平滑致密，表面均方根粗糙度逐渐减小。随工作压强增大，HGM的球形度没有发生明显变化，而壁厚均匀性得到不断提高，微球中C元素浓度逐渐降低，Si元素浓度不断升高，O元素浓度基本保持不变。

在乳液微封装技术制备聚苯乙烯空心微球的工艺中，固化过程是决定微球球形度及壁厚均匀性的关键阶段。基于乳粒发生器制备内径(850±10) μm、壁厚(250±25) μm的复合乳粒，以25 ℃,45 ℃和65 ℃作为固化温度，考察了固化温度对微球球形度和壁厚均匀性的影响。结果表明，固化温度越低，界面张力越高，乳液固化速率越慢，微球球形度和壁厚均匀性越好。当固化温度为25 ℃时，批次微球中球形偏离值优于2 μm的微球产率为90%，壁厚偏差值优于2 μm的微球产率为40%，明显优于固化温度为45 ℃和65 ℃时微球的质量。

为建立高效简洁的厚壁空心微球球形度和壁厚均匀性的表征和测量方法, 以内径850 μm、壁厚25 μm的厚壁聚苯乙烯(PS)微球为测量对象, 分析球形度和壁厚均匀性的表征方法, 探讨测量过程中采样方式对表征微球球形度和壁厚均匀性的影响。研究表明: 对于批量微球球形度和壁厚均匀性的表征, 当抽样数目不小于30时, 测量结果之间的差异很小; 而对于单一微球的球形度和壁厚均匀性的表征, 至少3个不同投影面的测量结果的平均值才趋于稳定。不同投影面导致球形度或壁厚均匀性较差的批次样品的测量结果有一定差异, 多次投影测量可提高测量结果的可靠性。

为了研究乳液微封装技术中油水相对微球壁厚的影响，推导了在理想状态下微球壁厚、油相质量分数和油水相比这三者之间的函数关系。结果表明：当内相水滴半径和油相质量分数为常数时，微球壁厚是油水相比的单增函数;而当内相水滴半径和油水相比为常数时，微球壁厚是油相质量分数的单增函数。即提高油相质量分数或增大油水相比对增加壁厚而言具有等效性。根据此规律，在搅拌法制备小直径聚苯乙烯微球中，通过调整油水相的各参数，确定了制备小直径厚壁聚苯乙烯微球的关键工艺参数。实验表明:采用搅拌法制备10~25 μm壁厚的小直径聚苯乙烯微球时，油相质量分数宜配制为5.3%~7.0%，油水相比宜控制在1.6~2.2之间，而外水相中聚乙烯醇质量分数宜控制在1%~3%之内。microspheres prepared by agitation method Liu Meifang,Liu Yiyang,Shi Ruiting,Chen Sufen,Su Lin,Li Jing,Li Jie,Li Bo,Zhang Zhanwen(Research Center of Laser Fusion, CAEP, P.O.Box 919-987, Mianyang 621900, China)Abstract:Key words: