Reduced angle sensitivity of structural coloration on an industrial aluminium platform

Existing structural coloration methods using thin films, commonly implemented in high‐purity aluminium, produce colours which are highly dependent on the viewing angle because of the inherent angular dependence of thin film interference. Adapting the thin film coloration mechanism to anodisation of industrial‐quality aluminium alloys, which scatter light more efficiently than their high‐purity counterparts, reduces angle dependence in the colour produced. This reduction of angle dependence, as well as the wide use of anodised aluminium in consumer products, suggests that structural colour based on anodised aluminium could potentially be scaled up for commercial scale production.     

Shear-induced orientation in polymer/clay dispersions via in situ X-ray scattering

We report in situ X-ray scattering measurements of shear-induced orientation in polymer-clay dispersions. Two different organically modified clays, montmorillonite and fluorohectorite, are dispersed in a low molecular weight, viscous polymer melt, facilitating studies at room temperature. Orientation measurements are performed in the flow-gradient plane, allowing characterization of both the average degree and direction of particle orientation during shear. In all cases, the orientation angle is finite, indicating systematic misalignment of the particle long axes relative to the flow direction. In concentrated fluorohectorite and montmorillonite dispersions, anisotropy and orientation angle are roughly independent of shear rate, and negligible relaxation is observed upon flow cessation. Conversely, a lower concentration montmorillonite sample exhibits orientation that is more responsive to shear flow, and partially relaxes upon flow cessation. In this sample, the orientation behavior is interpreted in light of rotational diffusion of the clay particles. This same sample exhibits oscillatory structural dynamics upon shear flow reversal, attributed to tumbling rotations of the disk-like clay particles in shear. Large-amplitude oscillatory shear is similarly demonstrated to be capable of inducing significant particle orientation; the degree of orientation is principally determined by the applied strain amplitude. Complementary measurements of rheological properties exhibit many characteristics commonly reported in polymer-clay nanocomposites. Based on the structural measurements reported here, the rheological phenomena are interpreted to arise from a combination of flow-induced particle orientation and rate- and time-dependent destruction or reformation of particle networks.     

Reproducibility of w/c ratio determination from fluorescent impregnated thin sections

The ease and reproducibility of preparing fluorescent epoxy impregnated thin sections for w/c determination of concrete has been studied. Five sets of thin sections were prepared from 6 concrete mixes having different compositions and w/c ratios (0.35 to 0.80). The thin sections were prepared by different technicians and produced over a period of nearly a year. The quality of the thin sections was checked and the w/c ratio determined by seven petrographers using fluorescent light microscopy as a Round Robin test.The investigation showed that, within a reasonable time, different technicians were able to produce a comparable quality of fluorescent epoxy impregnated thin sections, even though the thin sections were produced from concrete at different ages and using different equipment and chemicals. The petrographers were able to distinguish between the green shades of the fluorescent dye epoxy impregnated cement paste, with sufficient accuracy. The result of the w/c Round Robin test gave standard deviations between 0.02 and 0.03 (average 0.026).     

Particle Size and Optical Properties of Montmorillonite in Suspension

The light absorption spectra of monoionic montmorillonite suspensions with Li, Na, K, Rb, NH₄, Cs, Mg, Ca and Ba as adsorbed ions were studied in the wavelength range 200–800 mμ. Theoretical analysis of the spectra showed that in the visible range, only scattering is responsible for light intensity attenuation. The scattering was found to depend on the type of adsorbed ion and to increase systematically along the series from Li to Ba. This was attributed to increased particle size of the clay caused by parallel plate condensation to form tactoids. A geometrical model of a montmorillonite tactoid was assumed. The general dependence of the properties of such tactoids, and of their suspensions, on the number of plates per tactoid was formulated. Using the measured values of light absorbance index, and the theoretical model, the relative sizes, measured by the number of plates per tactoid, in the different ionic forms were calculated. The relative sizes thus estimated were found to agree favorably with relative sizes calculated from negative adsorption surface area measurements. A typical peak of specific light absorption was observed at 240–245 mμ, for both the suspensions and their clay-free supernatant solutions. Though the compound responsible for this peak is unidentified yet, its quantity in the various suspensions could be roughly estimated. The quantity was found to be negatively correlated with the relative size of the tactoid. It was concluded that the average particle size of montmorillonite in suspension markedly and systematically depends on the type of adsorbed ion. The implications of this finding are discussed.     

TiN薄膜的阳极氧化研究

研究了ＴｉＮ薄膜的阳极氧化。结果表明,在稀磷酸溶液中对ＴｉＮ薄膜进行阳极氧化处理后,在ＴｉＮ表面形成一层氧化膜。氧化膜呈干涉色,其颜色随槽压变化;氧化膜色调均匀,耐磨性好。ＸＰＳ及ＡＥＳ分析结果表明,氧化膜由ＴｉＯ２组成,且在槽压在９Ｖ时膜厚约９０ｎｍ。     

Dynamics and control of aggregate thin film surface morphology for improved light trapping: Implementation on a large-lattice kinetic Monte Carlo model

This work demonstrates the use of feedback control, coupled with a suitable actuator design, in manufacturing thin films whose surface morphology is characterized by a desired visible light reflectance/transmittance level. The problem is particularly important in the context of thin film manufacturing for thin film solar cells where it is desirable to produce thin films with precisely tailored light trapping characteristics. Initially, a thin film deposition process involving atom adsorption and surface migration is considered and is modeled using a large-lattice (lattice size=40,000) kinetic Monte Carlo simulation. Subsequently, thin film surface morphology characteristics like roughness and slope are computed with respect to different characteristic length scales ranging from atomic to the ones corresponding to visible light wavelength and it is found that a patterned actuator design is needed to induce thin film surface roughness and slope at visible light wavelength spatial scales, which lead to desired thin film reflectance and transmittance levels. Then, an Edwards–Wilkinson-type equation (a second-order stochastic partial differential equation) is used to model the surface evolution at the visible light wavelength spatial scale and form the basis for the design of a feedback controller whose objective is to manipulate the deposition rate across the spatial domain of the process. The model parameters of the Edwards–Wilkinson equation are estimated from kinetic Monte Carlo simulations and their dependence on the deposition rate is used in the formulation of the predictive controller to predict the influence of the control action on the surface roughness and slope throughout the thin film growth process. Analytical solutions of the expected surface roughness and surface slope at the visible light wavelength spatial scale are obtained by solving the Edwards–Wilkinson equation and are used in the control action calculation. The cost function of the controller involves penalties on both surface roughness and slope from set-point values as well as constraints on the magnitude and rate of change of the control action. The controller is applied to the large-lattice kinetic Monte Carlo simulation. Simulation results demonstrate that the proposed controller and patterned actuator design successfully regulate aggregate surface roughness and slope to set-point values at the end of the deposition that yield desired levels of thin film reflectance and transmittance.     

Colour gamuts arising from absorber–dielectric–metal optical resonators

Structural coloration is a quickly growing field, encompassing physical and photonic processes such as interference, diffraction, and scattering. In this study, we investigated the optical effects in the visible wavelength range, and in particular, the colour gamuts achievable with absorber–dielectric–metal sandwich structures. These chemical‐free layered structures are highly tunable, easily scaled, optical cavities that are capable of generating remarkable colours whose properties are determined completely by material and structural parameters. We employed experimental and numerical strategies to demonstrate that each absorber spans a unique colour gamut, i.e. a subset of the full chromaticity space. While gamut overlap is observed between different absorber types, the gamut areas unique to each absorber occur at different hues of high excitation purity. A comprehensive understanding of how these colour gamuts develop and how different materials may be combined to expand larger subsets of the chromaticity space is required in order to maximize the variety of colours achievable with this system and elevate it into a ‘structural coloration technology’.     

Artificial opals prepared by melt compression

In recent years, colloidal crystals with a refractive index varying periodically on the scale of the light wavelengths have been prepared by various methods. These photonic crystals reflect light and exhibit, at sufficiently strong contrast, even a complete band-gap in which light cannot propagate in any direction. Most studies published so far were aimed at such high-contrast photonic crystals with a complete band-gap or their precursors. Frequently, a face-centered cubic (fcc) lattice was built up from monodisperse polymer or silica spheres with diameters in the submicron range. Methods as sedimentation and drying of dispersions led to usually small and thin specimens. This report deals with films that were produced by a novel technique based on shear flow in the melts of polymer core-shell latex spheres. The process is fast and yields large area films, thin or thick, in which the latex spheres are crystallized in fcc order. The refractive index contrast of these purely polymeric films is too small for a complete band-gap photonic crystal, but the films are attractive color materials showing wavelength and angle dependent reflection colors.     

碳纤维复合材料圆梁弯曲振动有限元分析

碳纤维复合材料圆梁作为片状物料传送的旋转部件使用时,对其承载强度、刚度以及振动性能的要求一直较为严格。本文在结合材料力学和经典层合理论的基础上,利用ANSYS有限元软件建立三维圆梁模型,对碳纤维复合材料圆梁在定载荷下的弯曲和振动进行模拟。结果表明:纤维小角度铺层能提高圆梁的抗弯刚度,在考虑自重的定载荷条件下,壁厚变化与重力方向最大变形之间存在临界值;通过分析梁的振动模态,提取前6阶振动频率与振型,可知碳复合材料圆梁具有较强的抗振能力。     

Combined run-to-run and LQG control of a 12-inch RTP equipment

A combined run-to-run (R2R) and LQG control method has been proposed for rapid thermal processing (RTP) equipment for run-wise improvement and real-time multivariable control of the temperature uniformity over the wafer surface. The standard LQG objective was modified to include a quadratic penalty term for input deviation from bias values which are updated by an R2R control law. The proposed method has been applied to commercial 12-inch rotating RTP equipment with four pyrometers and ten circular groups of tungsten-halogen lamps for measurements and manipulation of wafer temperatures. The performance of LQG control was evaluated under wafer rotation and found to show quite accurate tracking. For evaluation of the combined control technique, a wafer with seven thermocouples (TC’s) attached along the radial direction has been employed for the TC measurements to be used for R2R control, whereas the pyrometer measurements are fed back for real-time LQG control. It was observed that the temperature uniformity is improved as the run number increases.     

FTIR Spectrometer for Measuring Toxic Smoke Components in Fire Testing—Review of Equipment and Calibration Routines in NT FIRE 047

The Fourier Transform infrared spectrometer method is developed by VTT Fire Technology in Finland, and is described by NORDTEST as NT FIRE 047. The method takes gas samples from the ventilation duct of a cone calorimeter, and is used to perform dynamic quantitative or qualitative measurements. This is an important step in the direction of continuous measurements of gas components in fire smoke. A lot of effort, knowledge and funds are required for a proper calibration and use of this equipment. The experience with application and interpretation of the test method is reviewed in regard to mounting, calibration and use of the equipment. The work concludes that the NORDTEST NT FIRE 047 test method needs to be revised and completed in the sections on apparatus, calibration routines, analysis procedure and expression of results. The missing information and details can lead to differences in application of the method. Until a revised document appears, frequent communication between laboratories can eliminate these differences.     

Polarization Dependence of the Cr3+ R-Line Fluorescence from Sapphire and Its Application to Crystal Orientation and Piezospectroscopic Measurement

The room-temperature polarization characteristics of the ruby R lines have been studied by monitoring the fluorescence intensity as a function of excitation direction relative to the crystallographic axes of the ruby crystal. The R lines are strongly polarized in the basal plane but have no preferred vibration direction within the basal plane. However, the degree of polarization, P, of the R1 and R2 lines is not the same, being P _R1=87% and P _R2=62%. The phenomenon is explained in terms of the absorption anisotropy and the probability of spontaneous emission. The findings provide the basis for a high-spatial-resolution spectrophotometric method to determine the optical c-axis of chromium-doped Al₂O₃ crystals using the angular dependence of the intensity ratio of the R2 line to the R1 line. The application to the orientation determination of sapphire fibers embedded in composites and the corresponding residual stress components are discussed together with the possibility of measuring the texture in the Al₂O₃ polycrystalline thin films such as oxidation scales. Furthermore, the consequences of polarization orientation on piezospectroscopic measurements are discussed.     

振动注塑对IPP/HDPE共混物力学性能和凝聚态结构的影响

研究了振动频率、振动压力对等规聚丙烯/高密度聚乙烯(IPP/HDPE)共混物力学性能和凝聚态结构的影响。结果表明,与未施加振动的静态试样相比,振动试样的力学性能得到提高。随着振动压力的提高,低频率振动试样的力学性能呈明显上升趋势;振动频率对低振动压力试样的力学性能影响较小。在试样的表层及次表层,聚合物晶体沿熔体流动方向均有明显的取向。而对于试样芯层,则只有在成型温度为190℃、振动频率为0.23 Hz、振动压力为90 MPa的条件下才能观察到明显的晶体取向。     

石化热设备表面红外仪检测温度校正方法

根据工业现场实际测得的石化热设备数据,提出一种基于热电偶的温度校正模型,并给出干扰因素影响规律的补偿方法。针对具体的风速、风向和附近热设备的影响,建立了修正补偿公式。现场实际结果表明所提方法能有效减小红外热像仪测量的温度误差,达到温度修正的目的。     

Experimental assessment of bench‐scale ignitability parameters

This work aims to explore possible ways of improving the precision of ignition measurements in the cone calorimeter. Both inherent repeatability of parts of the testing equipment and operator‐dependent variations are considered. Inherent repeatability is indicated to be slightly improved if the test samples used are circular rather than square. Operator‐dependent variation is discussed in terms of the method used for determining ignition. Four procedures are compared, namely, visual observation, usage of a light sensor, and looking at the peak of the second and first derivatives of the mass loss and heat release curves, respectively. Results indicate that the preferable operator‐independent method depends on the test conditions; the derivative of the heat release rate is an alternative to the mass loss rate derivative when the scale is of standardised quality. A light sensor for ignition time observation is a good option when the surrounding light is not changed during the test.     

专色油墨的配制

专色油墨的配制需一定的油墨色彩学知识。彩色油墨颜色有三种表达特征：色调、亮度和饱和度。彩色的干净与脏，是指彩色中出现的黑色多少而盲的。专色油墨调配分浅色和深色油墨的调配。专色油墨的调配方法分直接打小样和成品墨调配法。要掌握专色油墨的调配要点和调配技术才能熟练准确地调出合适的专色油墨。     

Nonhomogeneity of light modulation by PLZT retardation plates

Nonhomogeneity of light modulation by PLZT retardation plates - temporal due to the secondary electrooptic effect, and spatial due to the interference of directly transmitted and reflected light beams in birefringent substance has been discussed.     

Study on the Effect of Axial Vibration of Screw in Plasticating Process (Extrusion Part)

To improve the conformation of polymers, axial vibration is offered in the entire polymer process. Two sections, the axial shearing section and the axial pressing section, exert the effects of vibration on the melt. In the axial shearing section, with the effect of vibration, molecular chain orientations in the direction of flow and vibration produce the network frame, which ameliorates the mechanical properties, especially in the transverse direction, of the polymer product. The vibration can promote the disentanglement of molecular chains, which leads to a decrease in the viscosity and an increase in the flowability of melt. At the same time, it can ameliorate the blend quality of the filling system. Some experiments on extruded film, sheet, pipe, foam, and filling systems prove that the analyses are correct.     

Rapid Orientation of Sapphire Monocrystals

An optical method of orienting sapphire (α-Al₂O₃) single-crystal rods with respect to the basal plane has been devised. Measuring times are on the order of 1 minute per specimen, and the accuracy is to within a few degrees. The direction of inclination of the basal plane may be easily determined. Relations describing the relative intensity of light through a uniaxial crystal in a polarized light field have been derived. Simple equipment built around a photovoltaic cell has been used to confirm these relations experimentally.     

Performance of polyester and modified polyester coil coatings exposed in different environments with high UV radiation

Coil coating is a continuous strip coating technology, which enjoyed rapid growth. It provides a cost-effective method of applying a coating to a metal substrate with a low solvent emission, and nowadays paints of different nature are applied this way on a range of metal substrates, for a large variety of products and uses.

Coil coatings can be more or less degraded by high UV radiation. However, differences in distribution of light intensity as a function of wavelength between exposure environments, can lead to significant differences in the degradation results, depending on coating nature. In this work, the behaviour of polyester and silicone polyester coatings exposed in three different high UV environments (natural atmosphere and two accelerated UV tests), was studied. Coatings of two different colours (blue and brown) were considered for each paint system. Colour change, gloss and chalking measurements and, visual inspections of coating defects were carried out. In order to explain their corresponding performance, chemical changes on coil coated exposed surfaces were studied by to Fourier transform infrared spectroscopy equipped with a photoacustic detector (PAS/FTIR).