干凝胶法制备惯性约束聚变靶用大直径空心玻璃微球

为实现惯性约束聚变靶用大直径空心玻璃微球的干凝胶法制备,从数值模拟和工艺实验2个方面研究了发泡剂种类及含量、炉内载气组分、压力和温度对大直径空心玻璃微球制备过程的影响。结果表明:采用碱金属的乙酸盐作为发泡剂可以显著提高干凝胶粒子的发泡效率,提高载气中的氦气含量和升高炉温可以提高干凝胶粒子在吸热阶段的升温速率、更为迅速有效地完成封装过程,从而有利于大直径空心玻璃微球的制备。虽然降低载气压力有利于显著增大空心玻璃微球的直径,但是空心玻璃微球的品质急剧下降。当载气中氦气的体积分数为50%～80%、载气压力为(0.75～1.0)×105Pa、炉温为1500～1700℃时,干凝胶粒子的成球率较高、大直径(700～1000μm)空心玻璃微球的球形度、同心度和表面光洁度较好。     

惯性约束聚变靶用空心玻璃微球的干凝胶法制备技术

干凝胶法是我国目前制备惯性约束聚变(ICF)靶用空心玻璃微球(HGM)的主要方法,其制备的HGM可在较宽的范围内满足ICF物理实验的要求。从干凝胶粒子/微球的溶胶-凝胶法制备技术和HGM的炉内成球原理出发,系统综述了近三十年来ICF靶用HGM干凝胶法制备技术研究的相关报道,分析总结了干凝胶法制备技术在HGM成分设计、元素掺杂、直径及球形度、壁厚及均匀性、耐压强度、渗透性能、表面粗糙度、性能一致性等方面的技术现状及难点,对干凝胶法制备HGM技术的瓶颈性问题及可能的解决方案进行了讨论。     

靶丸用空心微球制备技术研究进展

激光驱动惯性约束聚变有望解决能源危机,但聚变过程条件的苛刻性对在其中充当靶丸材料的空心微球的品质,如球形度、壁厚均匀性、表面粗糙度、壳层材料密度等提出了严格要求,而制备方法的选择及条件控制直接影响到微球的上述性能。本工作主要综述了研究较为广泛的炉内成球技术、降解芯轴技术以及乳液法的制备过程、适用范围、优劣势等,并对乳液法的形成机理和影响因素进行了较详细的阐释。     

惯性约束聚变靶用空心玻璃微球纵横比的调控

为实现对惯性约束聚变(ICF)靶用空心玻璃微球(HGM)纵横比的调控,基于对干凝胶法制备HGM炉内成球过程的分析,建立了HGM纵横比的定量控制模型,实验研究了载气组分和压力对HGM直径和纵横比的影响。结果表明:通过调节载气中氩气分压可以控制熔融玻璃液泡的膨胀程度,从而定量控制最终HGM的直径和纵横比。但是,通过大幅度降低载气中的氩气分压来提高HGM半径和纵横比是不可行的。为提高载气的传热能力,确保HGM球形度、表面粗糙度和合格率满足ICF制靶的要求,必须在载气中添加一定分压的氦气。除部分极端工艺条件外,提出的HGM纵横比控制模型预测值与实验结果吻合良好。     

干凝胶法制备惯性约束聚变靶用高渗透性空心玻璃微球

为制备惯性约束聚变靶用高渗透性空心玻璃球（hollow glass microspheres,HGM）,研究了初始玻璃配方、发泡剂种类、炉内载气组分和压力、精炼温度对干凝胶粒子的炉内成球过程和最终HGM的产率、质量和渗透性能的影响。结果表明：初始玻璃配方中的绝大部分碱金属氧化物在精炼过程中都从液态玻璃挥发进入载气,最终...     

激光聚变靶用空心玻璃微球的成分设计

基于玻璃成分与性能之间的定量关系,以高强度、高化学稳定性、易熔和低粘度为目标,应用正交试验法对30种待选玻璃配方中Na2O、K2O、Al2O3、CaO的含量进行了优化,从中优选出了10种玻璃配方作为激光聚变实验靶用空心玻璃微球的候选配方.与国内外其它靶用空心微球玻璃的性能相比,候选配方的玻璃不仅化学稳定性和抗张强度有显著提高,而且各自的熔化温度、粘度等参数也满足空心玻璃微球炉内成球法的工艺要求.     

液滴法制备空心玻璃微球中初始液滴的定量形成

通过对液滴法制备激光聚变靶丸空心玻璃微球（HGM）中液滴形成过程予以分析,导出了射流初始速率、液滴直径及目标HGM直径分别与进为压力、小孔板孔径、射流振荡频率、溶液浓度及密度等因素的定量表达式,并在进料压力为13．7、18．7、23．6、28．5、33．4、38．3、43．2kPa和溶液中玻璃形成物浓度为1％、2％、4％、6％、8％、12％、16％下,测量了孔直径分别为108μm、142μm和168μm的小孔板的流量及流动系数,给出了射流初始速率、液滴直径及目标HGM中玻璃形成物含量的定量控制条件,实验结果符合定量表达式。     

干凝胶法制备空心玻璃微球炉内成球过程的数值模拟

基于对干凝胶粒子在干凝胶炉内吸热、封装、发泡、精炼和冷却过程的传热、传质和运动分析,建立了空心玻璃微球炉内成球过程的数学模型,并模拟了干凝胶粒子在炉内自由下落过程中温度、速度和直径的变化、粒子/微球与载气之间的温差及热传递系数在成球过程中的变化趋势.结果表明,在吸热封装阶段,干凝胶粒子表面升温速率非常高(1000～2000℃/s),能在很短时间(1s)和距离(4.5cm)内完成封装过程.提高载气的传热性能并不能显著增大液态玻璃微球的降温速率,提高制备炉冷却区的轴向温度梯度是增加其降温速率以提高空心玻璃微球几何对称性和表面粗糙度的关键.实验与模拟结果基本一致.     

空心玻璃微球高压贮氢技术

利用炉内成球技术制备的亚毫米量级空心玻璃微球进行实验,系统研究了玻璃微球高压贮氢技术.玻璃微球直径150～250 μm,壁厚0.9～4.0 μm.采用气体渗透法充氢,在高温时,气体扩散进入微球内,温度降低后气体不容易扩散出来,即可实现贮氢.通过控制外界温度和气氛可实现氢气的贮存和释放.对于直径200 μm,壁厚1 μm的空心玻璃微球,在350℃充气的平衡时间约6～10 h,充气平衡后,微球内外压基本相等.在室温条件下,微球的保气半寿命约40～50 d.对于直径200 μm,壁厚2 μm的空心玻璃微球,球内氢气最高压力可达20～25 MPa,单位质量贮氢效率为13%～16％.     

PS-PVA-CH塑料空心微球充D2

研究了激光惯性约束聚变靶用PS-PVA-CH三层塑料空心微球采用热扩散法高温高压充氘气技术。实验研究表明,对于直径300 μm、PS壁厚5～7 μm、PVA壁厚3～5 μm、CH层厚4～6 μm的塑料微球,50℃充气的平衡时间为20～40 h,70℃的平衡时间为7～12 h,90℃的平衡时间为2～4 h。在室温25℃时,微球的气体渗透系数为（3.0～4.2）×10^-19 mol·m^-1·s^-1·Pa^-1,对应的保气半寿命为28～37 h。对于参数接近的微球,如果充气时间相同,充气外压与微球内压基本呈正比。当外压达到6.0 MPa时微球开始出现破损。     

Fabrication and characterization of millimeter-sized glass shells for inertial confinement fusion targets

To fabricate target quality millimeter-sized glass shells for inertial confinement fusion (ICF) fuel micro-containers by sol–gel technology, the effects of gel particle properties and processing parameters on the diameter, quality and yield of resulting glass shells were investigated by simulation and experiments. The results show that the initial compositions and sizes of the gel particles, the blowing agents, the pressures and compositions of furnace atmosphere, the refining temperatures and the lengths of refining zone are the key parameters to obtain target quality millimeter-sized glass shells. Increasing the gel particle sizes and/or lowering the furnace atmosphere pressures, the resulting glass shell diameters increase rapidly but the sphericity, wall uniformity and surface finish decrease notably. Displacing argon gas with helium gas in the furnace atmosphere can significantly improve the glass shell diameters, quality and yields; however, keeping appropriate fraction of argon gas in the furnace atmosphere can reduce the fragmentation of the gel particles and the ripples and collapse on the shell walls. The quality and yields of the resulting glass shells can also be improved by increasing the temperatures and lengths of the refining zone.     

一步法制备生物相容油核微胶囊及其可控释放

一步法可控制备生物相容油核微胶囊对工业制备微胶囊及其应用具有重要意义。通过设计微流控器件,成功实现一步法制备尺寸均一可控的生物相容油核微胶囊。利用玻璃毛细管管套管的方法制备了微流控器件。通过外相水凝胶相剪切内相油相得到油核液滴,同时油核液滴和外相水凝胶相在重力作用下脱离管口,形成油核微胶囊,再通过交联水凝胶壳层得到稳定的结构。系统研究了微流控器件结构、内相流速、外相流速等参数对油核微胶囊油核数量、微胶囊直径、壁厚等性质的影响规律。生物相容油核微胶囊作为活性物质的理想载体,可以实现pH改变触发的快速释放和壁厚调节的缓慢释放,为其实际应用奠定了基础。     

Fabrication by photoinitiated polymerization and characterization of millimeter‐size poly(divinyl benzene) hollow foam shells

In this study, millimeter‐size compound droplets were prepared easily by a one‐step microfluidic method. We varied the diameter and wall thickness of the shells over a wide range by setting the flow rate. Poly(divinyl benzene) (PDVB) shells with a 3–4.8 mm diameter were fabricated through photopolymerization and supercritical drying. The gel point of photopolymerization was monitored by a rotational rheometer. Moreover, the influence of the oil‐soluble photoinitiator phenyl bis(2,4,6‐trimethyl benzoyl) phosphine oxide (BAPO) on the properties of the foam shell were investigated by transmission electron microscopy, scanning electron microscopy, and nitrogen sorption measurements. Significant differences in the mechanical properties and porous features were obtained for different BAPO concentrations. The surface areas of the foam shells decreased, and the densities of the foam shells increased with increasing BAPO concentration. In addition, the nonconcentricity and out‐of‐roundness values were mainly less than 7 and 3%, respectively, for most of the shells. The results indicate that the PDVB hollow foam shells are a promising inertial fusion energy target. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41625.     

Mathematical Modeling of Extrusion of Water–Oxide Pastes in the Production of α-Fe2O3 Catalysts

A mathematical model of preparation of a catalyst paste was developed with allowance made for the physicochemical features of phenomena occurring at this step. This model enables one to determine the thickness of the adsorption–solvation shells on solid-phase particles and also the concentrations of the components of the dispersion (continuous) phase as functions of time. It was found how the solvation shell thickness and the volume content of the solid phase in a paste affects its rheological and deformation properties. A mathematical model of the catalyst paste flow in a ram extruder is developed. An expression was derived for the extrusion pressure as a function of the paste flow velocity in the extruder. It was shown that this expression can be used to calculate the paste flow through an extrusion die with any number of channels. It was determined how the velocity at which the paste slides along the channel wall depends on the channel diameter.     

Preparation of Oxide Glass Films by Reactive Sputtering

A method of depositing oxide glass films on a substrate is presented. The method involves the sputtering of a metal or semiconductor electrode in an oxidizing atmosphere (so-called reactive sputtering). The films obtained are of good quality, unstrained, and adhere well to the substrate. Films of considerable thickness can be deposited and the substrate need not be heated during the process. The preparation of lead tellurite glass films, silica and germania glass films, silicate glass films, and stannate glass films is described. Some data on the kinetics of film growth and on the physical properties of these materials are presented.     

悬挂式支座的薄壁储液壳薄膜应力的简化计算

分析薄壁壳体的应力时,采用薄膜理论,应力沿厚度均匀分布,壳体材料的强度可以合理利用,是最理想的应力状态。而传统的薄膜应力计算方法比较复杂。针对两种不同结构形式的薄壁储液壳进行应力计算,得出求解薄膜应力的简便计算方法,该方法适用于能应用薄膜理论计算的任何一种薄壁储液壳的两向薄膜应力。     

Mid-Explosion Recovery of an Intermediate Phase of a Cylindrical Metal Shell

To understand the complex dynamic response of cylindrical metal shells under highstrain-rate loading, a mid-explosion recovery device is designed to recover cylindrical shells at an intermediary phase, chosen in this study to be the phase wherein cracks penetrate through the entire casing wall thickness. The surface dynamic processes of the expansion, fracture propagation, and rupture of a 40CrMnSiB steel cylindrical shell are measured with a high-speed framing camera for determining the appropriate inner diameter of the mid-explosion recovery device. The numerical simulation software Autodyn-3D is used to predict the influence of the device wall thickness and the maximum radial deformation of the device inner wall upon the outer fracture diameter of the casing. The casing at the desired phase is recovered by the device, and the outer diameter of the shell is found to increase by 1.77 times, while the radial deformation of the device is 5 mm. The crack distributions, the distance between the adjacent penetrating shear cracks, and the number of circumferential divisions are found to vary along the axis of the cylindrical casing.     

Cu_3N薄膜制备及其性能研究

Cu3N薄膜的晶面取向、沉积速率、电学特性等性质除与制备方法有关外,还和制备工艺参数有很大关系。溅射法制备Cu3N薄膜工艺参数主要有,混合气体(N2+Ar)中氮气分压比r、基底温度T(℃)、溅射功率P(W)。为了研究Cu3N薄膜的性能与其制备工艺参数之间关系,本文采用反应射频磁控溅射法,在玻璃基底上成功制备了Cu3N薄膜,并研究了工艺参数对其晶面取向、膜厚、电学性能、沉积速率的影响。     

Effect of polymer molecular structure on the quality of thin-walled hollow microspheres for inertial confinement fusion

Polymer microspheres can be used as fuel containers for laser inertial confinement fusion (ICF) due to their low atomic number, low density, and high thermal stability. The thin-walled polymer microspheres are prone to cracking due to an increase in the diameter to thickness ratio (diameter/wall thickness). The effect of polystyrene (PS) and Poly (α-methyl styrene) (PAMS) materials commonly used in ICF experiments on the quality of thin-walled microspheres is investigated. PS hollow microspheres show better sphericity, smoother surface, and lower cracking rate than PAMS microspheres. Moreover, the heat treatment of solidified PS microspheres can improve the strength so that the cracking rate of the microspheres decreases. The relative mechanism of how the molecular structure affect the quality is also discussed. This study provides some guidance for the preparation of thin-walled polymer microspheres with high quality for ICF experiments.