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.     

氘气透过高纵横比空心玻璃微球的实验研究

为了测试用于激光聚变实验的高纵横比空心玻璃微球(HGM)对D2气保气性能及计算HGM内D2剩余量,对3种常用配方HGM及其用0.5MNH4F＋0.1MHNO3洗液在90℃下处理后的HGM分别在573K下分三步热扩散充D2气,然后在290K下分别在0h、72h、144h时用气泡法测量HGM内的D2气压,由此测定了D2气体透过HGM的充气速率和漏气速率及其表观扩散活化能,并给出它们对D2保气半时间或充气半时间随HGM直径、壁厚和温度变化的计算式。     

氚气透过高纵横比空心玻璃微球的实验研究

为了测试用于激光聚变实验的高纵横比空心玻璃微球（HGM）对D2气保气性能及计算HGM内D2剩余量，对3种常用配方HGM及其用0.5MNH4F 0.1MHNO3洗液在90℃下处理后的HGM分别在573K下分三步热扩散充D2气，然后在290K下分别在0h、72h、144h时用气泡法测量HGM内的D2气压，由此测定了D2气体透过HGM的充气速率和漏气速率及其表观扩散活化能，并给出它们对D2保气半时间或充气半时间随HGM直径、壁厚和温度变化的计算式。     

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。     

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。     

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。     

漂浮型TiO2/石墨烯复合催化剂的制备及其性能

以空心玻璃微珠(HGM)为载体,采用水热法制备漂浮型石墨烯(RGO)-TiO_2复合光催化剂。首先将超声分散后的氧化石墨烯(GO)负载于经预处理后的HGM表面,而后以钛酸四丁酯为前驱体,在不使用还原剂条件下采用一步水热法制备出TiO_2/RGO/HGM复合光催化剂。研究了压力、GO(RGO)含量对复合光催化剂性能的影响。以罗丹明B(RhB)为降解对象分析了复合光催化剂的光催化降解效果。结果表明:GO成功负载于空心玻璃微珠表面,并通过水热过程在空心玻璃微珠表面原位还原生成RGO,二氧化钛形成RGO/HGM复合结构。此后,锐钛矿型TiO_2在RGO/HGM复合结构表面自组装成核并均匀负载从而形成TiO_2/RGO/HGM复合光催化剂。与TiO_2/HGM复合材料相比,TiO_2/RGO/HGM复合材料具有增强的光催化降解活性,再循环后具有良好的降解效果。此外,还提出了加载在HGM表面的RGO和TiO_2的可能机理和形成过程。     

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.     

基于两种烧嘴的铜精炼阳极炉内燃烧过程数值模拟

基于CFD软件Fluent 6.3对装配两种型式烧嘴的铜精炼阳极炉内的燃烧过程进行数值计算,分析了炉内气相燃烧过程的特点.结果表明,装配I型烧嘴时,保温期炉内火焰峰值温度为2301 K,火焰长度为2.3R(R为炉体半径),氧化期炉内火焰峰值温度为2506 K,火焰长度为2.0R;装配II型烧嘴时,保温期炉内火焰峰值温度为2610 K,火焰长度为1.85R,氧化期炉内火焰峰值温度高达2800 K,火焰长度为1.82R.装配I型烧嘴的阳极炉内温度较均匀,能更好满足阳极炉精炼的工艺需求.烧嘴结构和天然气速度、环氧速度与侧氧速度对阳极炉内气相燃烧过程有明显影响.     

The addition effect of hollow glass microsphere on the dispersion behavior and physical properties of polypropylene/clay nanocomposites

Polypropylene (PP) nanocomposites have been widely researched for last decade due to its high mechanical property and multiple usages in various industrial fields from automobile to consumer packaging. Dispersion of nanoclay in polyethylene and PP is the key factor due to their hydrophobic property. Adding surfactant or introducing a polymer with a functional group, and modifying a natural clay with organic ions have been tried to achieve the better dispersion of clay in polymer matrix. In this study, the PP/clay nanocomposite with maleic anhydride grafted PP and hollow glass microspheres (HGMs) at various compositions were prepared and characterized. The addition of HGMs to PP/clay nanocomposites significantly improved the tensile stress at yield point except 7 wt % of HGMs. It is assumed that this could be due to not only the reinforcing effect of HGMs in PP, but the crushing effect of HGMs on the clay resulting in interlayer increase of clay as well. The barrier properties was also found to be improved about 32% max resulting from the better dispersion and presence of HGMs. It could be assumed that the HGMs could act as a ball creating a ball milling crush force to achieve the better dispersion of clay in the polymer and improve nanocomposite performance. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47476.     

Lightweight polyethylene-hollow glass microspheres composites for rotational molding technology

Innovative composites based on polyethylene (PE) filled with hollow glass microspheres (HGMs) were formulated and successfully prepared as suitable plastic materials for rotational molding technology. The HGMs here used allow to attain lightweight materials with a reduced resin content and appealing aesthetical qualities. To enhance filler dispersion and phase adhesion, thus improving the ultimate properties of the composite materials, two compatibilization strategies were adopted: namely, surface modification of HGMs by dodecyl(triethoxy)silane or addition during mixing of a maleinized PE as in-situ coupling agent. The effectiveness of the surface treatments on HGMs was assessed by attenuated total reflectance Fourier-transform infrared spectroscopy and thermogravimetric analysis investigations. PE-based composites at various HGMs contents (5, 10, and 20 wt%) were prepared by melt blending. Morphology of untreated and modified HGMs, their dispersion in the composites as well as filler/matrix adhesion were investigated by SEM microscopy. Thermal, rheological and mechanical properties of the composites were studied in comparison with neat PE. Rotational molding tests carried out both in laboratory and industrial site demonstrated the feasibility of producing lightweight plastic items (weight reduction up to 17%) of excellent aesthetics on a large scale.     

Non-Isothermal Crystallization of Poly(Vinylidenefluoride)/Hollow Glass Microspheres Composites

The Poly(vinylidene fluoride)/Hollow glass microspheres(PVDF/HGMs) composites were prepared by the method of solution blending. The non-isothermal crystallization of the PVDF and its composites were investigated with a differential scanning calorimeter (DSC). The results showed that the crystallization peaks shifted to a lower temperature and became wider with an increasing cooling rate. The HGMs caused to increase in crystallization temperature and initial crystallization temperature. In addition, the Jeziorny and the Mo methods were used to analyze the non-isothermal crystallization kinetics. The results showed that the crystallization rate rose with the cooling rate rising, however, the HGMs decreased the crystallization rates of the PVDF.     

Preparation of lightweight hollow glass microsphere ceramics by gel casting

Owing to low density, hollow glass microspheres (HGMs) float on common media such as water, ethanol, and tertiary butanol. As a result, HGMs are not suitable to prepare slurries and ceramics by gel, slip, and freeze castings. In this paper, polyacrylamide (PAM) was used as dispersant and thickener agent to prepare homogeneous HGM aqueous slurries with controlled solid loadings and subsequent lightweight HGM porous ceramics were prepared by gel casting. Effects of PAM content on the stability of aqueous slurries as well as effects of solid (i.e., HGM) loading on density, porosity, pore size distribution, and compressive strength of porous ceramics were investigated. Increasing the viscosity of the slurry resulted in HGMs with significantly lower floating rates and more stable HGM aqueous slurries. HGM porous ceramics with densities and compressive strengths of 0.127–0.219?g/cm³ and 0.74–1.71?MPa, respectively, were prepared by gel casting.     

Mechanical behavior of glass fiber-reinforced Nylon-6 syntactic foams and its Young's modulus numerical study

Glass fiber-reinforced Nylon-6 syntactic foams (GRSF) were fabricated by melt mixing, adding silane-modified hollow glass microspheres (HGMf) at 5, 10, 15, and 20 wt% and an impact modifier at 15 wt. Tensile test results showed that the foam's strength increased with the addition of HGMs but started to decrease when the volume fraction of the spheres was higher than 18 vol% (10 wt%). To elucidate the reinforcement mechanism, a numerical simulation of GRSF was carried out. It revealed that HGMs progressively become the reinforcement phase of GRSFs, as their volume fraction increased due to the load transfer occurring more readily in the HGMs than the fiber, which is expected to be the reinforcement. Hence, for a desired weight-strength ratio, thicker walls are necessary to delay the elastic relaxation of the microspheres and the impairing of the composite as a whole in the context of strength. HGMs with relative wall thickness τ = 0.04 produce an impairing on Young's modulus, if the volume fraction of microspheres is exceeded than 18 vol% because the microspheres are not able to endure increased loads. In addition, a significant reduction of the density was observed by up to 12% in the GRSFs with 30 wt% of both fibers and HGMs. The insight gained of GRSFs role and the numerical simulation achieved through this work, is a significant step toward developing applications of these lightweight materials, since they show good combination of strength, toughness, density, and thermal insulation performance, which can be useful in the automotive, aeronautical and sports industries.     

Developing a hollow glass microsphere/geopolymer thermal insulation composite for hot metal surface coating

Manufacturing inorganic thermal insulation materials with superior properties such as low thermal conductivity (k < 0.1 W/mK) and high mechanical properties in terms of adhesion strength is critical for energy efficiency in energy-intense industries. Geopolymer-based composites composing of hollow glass microspheres (HGMs), waste fly ash (FA), and metakaolin (MK) were successfully applied on hot (T～300 °C) metal surfaces via spray deposition technique. The effect of Si/Al and Na/Al mole ratios and HGM loading on geopolymer composites' physical, microstructural, thermal, and adhesion strength properties were explored. The best composite composition was obtained when Si/Al mole ratio, Na/Al mole ratio, and HGM loading were 2.5, 1.0, and 10 wt %, respectively. This composition achieved an HGM/geopolymer composite material with low thermal conductivity (k ～ 0.05 W/mK), high adhesion strength (～5.0 MPa), and high stability under immersion in water and vibration environments (particularly exposed to water). The results showed that HGM/geopolymer composites could be used as a thermal insulation material in energy-intense industries.     

Study on the performance of syntactic foam reinforced by hybrid functionalized carbon nanotubes

Hollow glass microspheres (HGMs)/epoxy syntactic foam were reinforced by hybrid functionalized carbon nanotubes that were synthesized by simultaneous covalent and noncovalent functionalization of carbon nanotubes. The effect of hybrid functionalized carbon nanotubes on density, mechanical properties, and water absorption of HGMs/epoxy syntactic foam was studied. The study indicated that the dispersion of carbon nanotubes in epoxy resin can be improved by hybrid functionalization. The compression strength of syntactic foam reinforced by hybrid functionalized carbon nanotubes was significantly enhanced. The maximum compressive strength of syntactic foam corresponding to chitosan modified carbon nanotubes approached 60 MPa. Hybrid functionalized carbon nanotubes had little effect on the water absorption ability of syntactic foam, and was less than 1%. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48586.     

Poly(methyl methacrylate) hybrid syntactic foams with hollow glass microspheres and polyhedral oligomeric silsesquioxanes

The study aims to produce poly(methyl methacrylate) (PMMA)-based lower density syntactic foams with hollow glass microspheres (HGMs) and to improve their mechanical properties by the addition of polyhedral oligomeric silsesquioxanes (POSSs) while maintaining the thermal properties of the neat polymer. First to understand the effect of POSS addition, PMMA–POSS composites with octaisobutyl and octaphenyl POSS were produced through extrusion. Higher relative flexural and impact strengths were obtained with POSS addition to PMMA. Obtaining more enhanced properties with octaphenyl POSS, PMMA-HGM-POSS hybrid syntactic foams were prepared with this additive. In general, the specific flexural strength and modulus of the PMMA syntactic foams were improved with the POSS loading, while the lower density and thermal properties of the PMMA syntactic foams were maintained. PMMA hybrid syntactic foams with 15 wt % HGMs and 0.25 wt % POSS exhibited 37.6% improvement in the specific flexural modulus with respect to the neat PMMA. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48368.