Motion of Enzyme‐Powered Microshell Motors

Microshells are attractive in constructing bubble‐propelled micromotors due to the lower energy consumption for bubbles forming on a concave surface. In this work, enzyme‐powered microshell motors were fabricated on multimetallic (Au/Ag/Au) microshells along with the modification of catalase on its concave surface. The catalase triggered the decomposition of hydrogen peroxide to oxygen gas, hence propelling the autonomous motion of microshell motors. A size‐dependent motion behaviour was observed for the microshell motors in the form of slow tremble and fast translation motion for a size smaller and larger than 5 μm, respectively, according to the size, generation efficiency and ejection mechanism of bubbles and the intensity of Brownian motion. In addition, the effect of fuel concentration on the motion speed of microshells was dependent on whether the bubble generation was affected by the limited mass transfer in the microshell space. These findings play an important role for the design of microshell motors.     

制备大直径无气泡聚苯乙烯空心微球

 高品质聚苯乙烯（PS）空心微球是惯性约束聚变（ICF）实验用多层塑料微球靶的重要芯轴,常由乳液技术制备。针对由乳液技术制备的PS微球壳壁内容易形成气泡而且大直径微球制备困难的问题,实验研究了对壳壁内存在的气泡以及消除方法和制备大直径PS微球的制备技术。     

Creation of a diagnostic complex for the characterization of cryogenic laser-fusion targets using the tomography method with probing irradiation in the visible spectrum

We present our results on developing a diagnostic complex for high-precision characterization of the parameters of laser-fusion microobjects, such as microspheres and cryogenic targets (the microobject size is 1–2 mm). The complex operates based on the principle of tomography. The complex consists of (a) the scanning system providing a set of shadow projections of a microobject in the visible range of radiation and (b) specially developed software for 3D reconstruction of the microobject from the set of projections. The spatial resolution of the optical system is 1 μm for a probing-radiation wavelength of 490 nm. The distinctive features of the diagnostic complex are (1) operation with both free-standing and mounted targets and (2) the possibility of scanning the targets from room to cryogenic temperatures. The operation of the complex was demonstrated in the reconstruction of polystyrene microspheres by a large set (80–90) of shadow projections at room and cryogenic temperatures.     

微封装法制备聚苯乙烯空心微球的改进

 主要介绍了密度匹配微封装技术，利用此项技术制备的聚苯乙烯空心微球 球形度好于99%，同心度好于98%。另外还对球壳内壁气泡问题及大直径球壳的制备进 行了讨论。     

金锥-聚合物球壳靶制备初步研究

 报道了研制快点火物理实验用带金锥固体球壳靶时,采用多次乳化技术制备聚合物空心微球,精密车床加工和电镀技术制备金锥,精密加工实现聚合物微球表面打孔的工艺。窄分布聚苯乙烯制备的空心微球直径与壁厚分布较窄。电镀液的配方、pH值、镀前处理、尖端效应等对镀层的表面质量和镀层与芯轴之间的结合力有重要的影响。采用精密车床加工可以在聚合物微球表面获得直径约120 μm的孔,初步实现金锥与聚合物微球的连接。     

高品质空心聚合物微球的研制

成功的惯性约束聚变(ICF)实验对氘氚(DT)燃料容器(靶丸)的球形度,同心度、表面光洁度及壳壁完整性均有极高要求.我所于90年代初开展了聚合物靶丸的研制工作,并利用微封装技术成功地制备出聚苯乙烯(PS)空心微球[1].但是在徽封装技术的固化过程中,由于重力和浮力的共同作用,有机相液滴在水溶液中的漂浮会对微球的球形度和同心度造成一定影响,并且有机溶剂内微量的过饱和水会在球壳壁内形成大量直径微米级的气泡.为此我们开发出密度匹配微封装技术,保持有机相和水相密度一致,从而克服了重力的影响,制备出球形度好于99%,同心度好于98%的空心PS微球.将制球溶液经过G3玻璃砂漏斗过滤后使用,减少溶液内杂质粒于的数量,结果球壳壁内的气泡大大减少.另外为了满足今后ICF实验对大直径靶丸的要求,通过改变乳化搅拌方式和降低搅拌速度,制备出直径达到510μm的PS微球.现在的研究工作为今后ICF多层聚合物靶丸的研制奠定了坚实的基础.