The Effect of Run Time on the Inter-Unit Uniformity of Aqueous Film Coating Applied to Glass Beads in a Hi-Coater

Abstract

Coating experiments were conducted to assess the inter-unit uniformity using individual weight gains of glass beads. Applying more aqueous film coating and prolonging the film-coating process by diluting the coating suspension did improve the coating variability among glass beads. It appears that run time is an important underlying factor which affecting the inter-unit coating uniformity.     

空心玻璃微珠用量对涂料反射和隔热性能的影响(英文)

本文通过空心玻璃微珠涂料反射实验、隔热实验和SEM分析研究空心玻璃微珠用量对涂料反射和隔热性能影响,结果表明:空心玻璃微珠的适宜添加量为25%,反射率能达45%-65%,能降温9℃;涂料反射隔热性能主要是由空心玻璃微珠对太阳光具有反射和阻隔作用引起,其次还与空心玻璃微珠在涂层表面的排布有关。在空心玻璃微珠用量为25%时,空心玻璃微珠在涂层中形成由无数空腔形成的致密的阻隔层来反射太阳光和阻止热传导。     

一种新型隔热涂料的制备及性能研究

以苯丙乳液为成膜剂,硅烷偶联剂处理后的中空玻璃微珠为功能隔热填料合成新型的隔热涂料。结果表明,用硅烷偶联剂预处理中空玻璃微珠后涂料附着力能提高1个级别;涂层导热系数随中空玻璃微珠粒径的增加呈现先减小后增大的趋势,当中空玻璃微珠的粒径为58μm左右时导热系数比其它粒径制得涂料的导热系数降低6%～28%;随涂膜厚度的增加,隔热效果增强,但当涂膜厚度增大到0.3mm时,继续增加涂膜厚度,隔热效果几乎不再增强;当中空玻璃微珠含量小于10%时,热反射率随中空玻璃微珠在隔热涂料中含量的增加显著增加,超过10%后,热反射率增加速率减缓,当达到12%时,涂料的热反射率值最高,继续增加玻璃微珠含量,热反射率几乎不增加。     

Effect of interface on the mechanical behaviour of glass bead-filled PVC

The surface of glass beads of average particle size 100m was modified (a) by incorporating extra hydroxyl groups by chemcial treatment, and (b) by applying a thin coating of polymethacrylic acid (PMA) on the glass surface. The corresponding chemical changes were investigated using infrared spectroscopy. The tensile behaviour of a glass bead-filled PVC composite prepared with surface-modified glass beads, showed the following effects: (a) hydroxyl groups incorporated on to the glass surface did not affect the glass-PVC interface and hence did not change the tensile behaviour of the composite; (b) PMA coating on the glass surface caused improvement in the tensile behaviour in the low strain region and deterioration in the high region. An SEM study of the fractured surface suggested debonding at the glass-PVC interface in the first case, and failure of the PVC-PMA interface in the second case.     

Balanceregelung für reaktives Magnetronsputtern zur optischen Großflächenbeschichtung

Best prerequisites for long term stable optical coating are given by reactive Dual Magnetron Sputtering. Requirements for components and techniques for architectural Low‐E coating and TCO coating are discussed. Reliable process stabilization at high deposition rates is possible using Plasma Emission Monitor (PEM) control circuits. The use of multichannel PEM control allows a balance control to improve both the film thickness uniformity and reproducibility of working points for large area coating on glass or web. Examples of horizontal and vertical glass coater for deposition of optical multilayers for different applications are presented.     

The effect of low energy impact on the tensile strength of coated and uncoated glass particulate composites

The residual tensile strength of glass filled particulate composites has been determined after low energy impact for various energy values. The material systems constructed for the needs of this research consisted of epoxy resin filled with glass beads. The glass beads were either uncoated or alternatively coated with a reactive silane based bonding agent. Specimens with various filler volume fractions were available. The effect of silane coating as well as the filler volume fraction was analytically discussed. Finally, a model developed in previous work for continuous fibre reinforced composite laminates was adopted to describe the residual tensile strength after impact. In most of the cases the predicted curves fit the experimental results very well.     

新型保温隔热外墙涂料的研制

以碳酸钙、金红石型二氧化钛、空心玻璃微珠、氧化锌为颜填料,以苯丙乳液为主成膜物,制备出的建筑外墙保温隔热涂料,其常规性能符合外墙涂料的相关标准要求。研究了添加碳酸钙、金红石型二氧化钛和氧化锌三种填料及复合添加四种填料对涂层隔热性能的影响。结果表明：添加碳酸钙、金红石型二氧化钛和氧化锌可提高涂层隔热性能;复合掺入碳酸钙、金红石型二氧化钛、氧化锌和空心玻璃微珠可进一步提高涂层隔热性能。掺加15％碳酸钙、7％金红石型二氧化钛、5％氧化锌和8％空心玻璃微珠时,隔热温差为7．9℃,导热系数为0．0767W／（m·K）,具有明显的保温隔热效果。     

Bioactivity of degradable polymer sutures coated with bioactive glass

Novel bioactive materials have been prepared by coating violet resorbable Vicryl sutures with a bioactive glass powder derived from a co-precipitation method. Two techniques have been chosen for the composite preparation: pressing the sutures in a bed of glass powder and slurry-dipping of sutures in liquid suspensions of bioactive glass powders. The uniformity and thickness of the coatings obtained by the two methods were compared. The bioactivity of the sutures with and without bioactive glass coating was tested by soaking in an inorganic acellular simulated body fluid (SBF). The composite sutures were characterised by XRD, SEM and FTIR analyses before and after soaking in SBF solution to assess the formation of hydroxyapatite on their surfaces, which is a qualitative measure of their bioactivity. The possible use of bioactive sutures to produce tissue engineering scaffolds and as reinforcement of resorbable calcium phosphates is discussed.     

Influence of surface characteristics of modified glass beads as model carriers in dry powder inhalers (DPIs) on the aerosolization performance

The aim of this work is to investigate the effect of surface characteristics (surface roughness and specific surface area) of surface-modified glass beads as model carriers in dry powder inhalers (DPIs) on the aerosolization, and thus, the in vitro respirable fraction often referred to as fine particle fraction (FPF). By processing glass beads in a ball mill with different grinding materials (quartz and tungsten carbide) and varying grinding time (4?h and 8?h), and by plasma etching for 1?min, glass beads with different shades of surface roughness and increased surface area were prepared. Compared with untreated glass beads, the surface-modified rough glass beads show increased FPFs. The drug detachment from the modified glass beads is also more reproducible than from untreated glass beads indicated by lower standard deviations for the FPFs of the modified glass beads. Moreover, the FPF of the modified glass beads correlates with their surface characteristics. The higher the surface roughness and the higher the specific surface area of the glass beads the higher is the FPF. Thus, surface-modified glass beads make an ideal carrier for tailoring the performance of DPIs in the therapy of asthma and chronically obstructive pulmonary diseases.     

V-N共掺杂TiO_2/玻璃珠光催化复合材料的制备及光催化性能

用溶胶-凝胶法制备V-N-TiO_2/玻璃珠光催化复合材料,研究V-N-TiO_2(V-N-TiO_2)的浓度、V-N-TiO_2/玻璃珠的浸渍次数、玻璃珠尺寸、煅烧温度和煅烧时间对V-N-TiO_2/玻璃珠光催化复合材料光催化性能的影响。采用XRD、EDS、TEM、XPS等测试手段对复合材料的结构和性能进行表征;在100 W汞灯下,以苯酚溶液为目标降解物,对V-N-TiO_2/玻璃珠光催化复合材料光催化性能进行测定。研究表明:当V-N-TiO_2/玻璃珠的浸渍次数为4次、玻璃珠尺寸为2~3mm、煅烧温度为400℃和煅烧时间为4.5h时,得到的V-N-TiO_2/玻璃珠光催化复合材料对苯酚的光催化性能最佳,且单位催化剂对苯酚的降解量略高于V-N-TiO_2。V-N-TiO_2/玻璃珠光催化复合材料既易于回收,又具有良好的光催化性能。     

机械镀锌沉积机理的研究

通过蒸发皿模拟试验和生产试验,采用体视显微镜观察了机械镀锌形层过程中金属锌粉在预镀工件表面的吸附、沉积过程,并用光学相机记录了金属锌粉的沉积过程.运用物理化学、电化学的基础理论分析了金属锌粉的沉积机理.分析结果表明,基层建立阶段,金属锌粉和Sn2+发生化学反应;镀层增厚阶段,金属锌粉和M2+发生化学反应;金属锌粉表面化学反应造成的库仑引力和机械镀锌过程玻璃珠冲击介质的碰撞是锌粉沉积的主要原因.     

Erosion behavior and failure mechanism of Ti/TiAlN multilayer coatings eroded by silica sand and glass beads

Severe erosion by hard particles is a crucial problem to engine blades when aircraft take off and land in harsh environments,especially for the developed lightweight titanium alloy components.Here,we deposited the Ti/TiAlN multilayer coatings with various cycles on Ti-6Al-4V substrates by a home-made hybrid multisource cathodic arc system.The effects of the silica sand and glass beads on erosion behavior of the coatings were focused.Results showed that the Ti/TiAlN multilayer coatings eroded by the silica sand exhibited the predominant "layer by layer" failure mechanism.In particular,increasing the number of cycles led to the dramatic increase in erosion rate for Ti/TiAlN multilayer coatings,due to the deterio-ration of their mechanical properties.Different from the silica sand case,however,the erosion rate of the coatings treated by glass beads indicated faint dependence upon the number of cycles,where the coating failure was dominated by the "piece by piece" failure mechanism.Noted that the Ti layers along with the formed interfaces enhanced the erosion resistance of the coatings,although the failure mechanisms were differently eroded by silica sand and glass beads.Meanwhile,the Ti layers and interfaces hindered the propagation of radial cracks and restrained the lateral cracks within one single TiAlN layer.     

椭球反射镜膜厚均匀性与工艺技术的探讨

讨论了深紫外曝光系统中椭球反射镜镀制装置在薄膜沉积中的镀制条件对膜厚和膜厚均匀性的影响,计算了椭球镜的膜厚均匀性并对如何改善椭球镜膜厚分布作了介绍,实验得到均匀性符合要求的反射镜。     

On sintering of tiny glass beads in oscillating diametric compressions

Sintering of tiny spherical glass beads induced by oscillating diametric compression at room temperature is considered. The amorphous glass beads are modeled as isotropic elasto-plastic solid with bilinear stress-strain constitutive relationship, which is implemented in a finite element code. The coupled thermal and mechanical response of the glass beads under cyclic compressions is investigated. Our numerical simulations show that the local temperatures and stresses near the contact points can significantly be raised during adiabatic compression cycles. The temperature rise is more pronounced for contact between two beads with different sizes or for contact with more neighboring beads. There exist temperature and stress gradients from the interiors toward the contact points. These findings provide a feasible explanation for the sintering found in recent triaxial compression experiments with tiny glass beads under room temperature and low pressure.     

Bead Coating: II. Effect of Spheronization Technique on Drug Release from Coated Spheres

The effect of spheronization method on drug release from coated spheres may be evaluated by determining the drug release rate, the critical coating level and the release mechanism. Drug release is faster from pan beads than from marumerizer beads at the same coating level. An equation is proposed which indicates that the critical coating level is inversely proportional to sphere size and sphere density, which in turn results from the different spheronization techniques. From the calculation, the critical coating levels for 14/16 mesh cuts of marumerizer beads and pan beads are 12% and 18%, respectively. Disintegration, pore-control and barrier control are involved in the release mechanisms of drugs from coated pan beads.     

The Influence of Tablet Shape and Pan Speed on Intra-tablet Film Coating Uniformity

Four different tablet shapes (round, oval, capsule, and large oval) were coated in a small-scale coating pan at three different pan rotational speeds. The coating film thickness was measured on the top face, the edge of the land, and the belly band of each tablet shape. The results showed that tablet shape directly influences intra-tablet coating uniformity (uniformity decreasing from round, oval, capsule, to large oval). In almost all cases, coating uniformity increased with pan speed.     

Bead Coating Process Via an Excess of Crosslinking Agent

Coated beads were prepared by soaking in sodium alginate solutions spherical matrices (beads) of carboxymethylcellulose crosslinked with aluminum chloride (AlCl3) and loaded with ambroxol hydrochloride as a model drug. The residual amount of the crosslinker induced an interfacial crosslinking reaction of the sodium alginate. Therefore, an insoluble, smooth and uniform in thickness coat was formed around the beads. As the coating time increased, the coat thickness increased until1 AlCl3 was present inside the beads. The rate of drug release from the coated beads was slower than that from the uncoated beads and decreased with the increase in coating time. Moreover, a constant rate phase, subsequent a burst period for the samples obtained with the highest coating times, was achieved. The dynamic swelling analysis allowed to exclude the influence of the polymer relaxation on the release process which appeared to be controlled by the alginate coat.     

Study of the refractive index of microscopic glass beads by light-refraction analysis

The refractive index of submillimeter glass beads has been measured by means of a novel, to our knowledge, procedure with reference liquids that does not require close index matching and therefore avoids the use of toxic compounds for high-index glasses (i.e., n >/= 1.8). The method is based on the analysis of the light refracted by a monolayer of beads in comparison with ray-tracing simulations. For the three different types of glass beads investigated a satisfactory fit is achieved by the assumption of a radial variation of the refractive index inside the beads. This is ascribed to the tensile and compressive stresses originating inside the beads during rapid solidification of the glass.     

Bead Coating: II. Effect of Spheronization Technique on Drug Release from Coated Spheres

Abstract

The effect of spheronization method on drug release from coated spheres may be evaluated by determining the drug release rate, the critical coating level and the release mechanism. Drug release is faster from pan beads than from marumerizer beads at the same coating level. An equation is proposed which indicates that the critical coating level is inversely proportional to sphere size and sphere density, which in turn results from the different spheronization techniques. From the calculation, the critical coating levels for 14/16 mesh cuts of marumerizer beads and pan beads are 12% and 18%, respectively. Disintegration, pore-control and barrier control are involved in the release mechanisms of drugs from coated pan beads.     

PECVD法沉积大尺寸氮化硅薄膜性能的研究

采用等离子体增强型化学气相沉积(PECVD)法在大尺寸玻璃基板上沉积氮化硅薄膜,对薄膜性能进行了研究,并从微观角度对所得结论进行了进一步分析与讨论.PECVD法在连续沉积氮化硅薄膜时,薄膜的厚度、沉积速率、均一性以及致密度会随镀膜基板数变化.结果 表明,随镀膜基板数量的逐渐增加,氮化硅薄膜平均厚度呈上升趋势,均一性变好...