Image Analysis and Modeling of the Orientation of Pores in a Constrained Film on a Rigid Substrate

The nature of porosity in functional materials is often a critical parameter in determining their functionality, for example, in structure materials and fuel cell electrodes. Here, we study the development of the anisotropy of porous yttria‐stabilized zirconia (YSZ), focusing particularly upon the contribution of pore orientation to this anisotropy. Simulation from when the ink is deposited on the surface of a rigid substrate shows that platelike pores are found tend to align along the transverse direction of the substrate. Cross‐sectional image analysis of the pores from the attendant pores of YSZ particles or pore‐forming agent (PFA) matches with the simulated modeling when materials transport is insignificant in determining the shape of pores. The anisotropy created in the densification stage is separated from that in the green body by analyzing the image of porous structures formed with spherical glassy carbon which is unable to contribute to anisotropy during green‐state processing.     

Influence of GaAs Substrate Orientation on InAs Quantum Dots: Surface Morphology, Critical Thickness, and Optical Properties

InAs/GaAs heterostructures have been simultaneously grown by molecular beam epitaxy on GaAs (100), GaAs (100) with a 2° misorientation angle towards [01−1], and GaAs (n11)B (n = 9, 7, 5) substrates. While the substrate misorientation angle increased from 0° to 15.8°, a clear evolution from quantum dots to quantum well was evident by the surface morphology, the photoluminescence, and the time-resolved photoluminescence, respectively. This evolution revealed an increased critical thickness and a delayed formation of InAs quantum dots as the surface orientation departed from GaAs (100), which was explained by the thermal-equilibrium model due to the less efficient of strain relaxation on misoriented substrate surfaces.     

塑料部件紫外光固化涂层起泡问题研究

以紫外光固化涂料涂装塑料部件后其涂层产生的起泡现象为研究对象,通过显微镜观察和元素分析方法对产生气泡的涂层进行表征和分析,总结了气泡的类型和产生的原因,并提出了相关的建议及解决办法。     

新型纤维素薄膜的NMMO生产工艺

介绍了新型纤维素薄膜的 NMMO制造工艺 ,并指出和传统的粘胶工艺相比新工艺具有无污染、能耗小、产品性能好的优点。     

Effect of Cellulose Characteristic and Hydrolyze Conditions on Morphology and Size of Nanocrystal Cellulose Extracted from Wheat Straw

In this paper, preparation and characterization of cellulose and nanocrystalline celluloses (NCC) and the effect of cellulose characteristic and hydrolyze conditions on the morphology and size of the obtained NCC will be discussed. Two different celluloses were prepared by two procedures, A and B, then the cellulose obtained was hydrolyzed under the same conditions. The result showed that the morphology and size of the nanocrystals obtained are not only attributed to the cellulose sources, but also to the hydrolyze conditions.     

Effect of Substrate Orientation, Roughness, and Film Deposition Mode on the Tensile Strength and Toughness of Niobium–Sapphire Interfaces

The strength and toughness of interfaces between sputter-deposited polycrystalline niobium films and sapphire substrates with basal and prismatic orientations were measured. The effect of deposition parameters and substrate roughness on these interface properties also was investigated. Substrates of polycrystalline alumina with two different surface morphologies were chosen for studying the effect of interface roughness. The interface strength was measured using a previously developed laser spallation experiment in which a laser-generated compressive stress pulse in the substrate, upon reflection into a tensile stress pulse from the coating's free surface, pulls the interface apart. The interface toughness was obtained using a controlled delamination technique, in which a residually stressed loading layer was used to buckle the underlying test layer from its substrate. The energy balance in the prebuckeled and postbuckled states provided a direct measure of the interface toughness. These values were independently obtained by another experiment in which well-characterized, artificially generated, interfacial flaws were loaded using a stress pulse in the laser spallation assembly. The coating's free surface velocity upon crack initiation was related to the critical energy release rate via a numerical simulation. The results of the two toughness experiments conformed to each other and related fairly well to the independently obtained strength measurements.     

降香黄檀/纤维素抗菌复合膜的疏水改性

为改善纤维素薄膜易吸潮的缺点,并保持其生物可降解性,利用安全无毒、可食用的单硬脂酸甘油酯、大豆卵磷脂,对降香黄檀/纤维素抗菌共混膜表面进行疏水改性.将两种小分子溶液用旋涂法涂覆于薄膜表面,并对改性后复合膜的分子结构、疏水性能、力学性能、透光性能以及阻隔性能进行系统研究.实验结果表明,单硬脂酸甘油酯改性后的复合膜具有优异...     

Affinity of Direct Dyes for Cellulose Film

A fast spectrophotometric method of assessing the affinity of different substances for surfaces is proposed. The effect of the dyeing temperature and concentration of the dye bath components (electrolyte and dye) on the value of the affinity of direct dyes for cellulose fibres was investigated. The optimum values of the temperature and concentrations of dye and electrolyte with respect to the affinity of the dye for the fibre were found. A series of experiments to investigate the effect of enzymes and surfactant additives on the affinity of the dye for the fibre was conducted and the insignificant effect of these components on the dyeing process was demonstrated.__________Translated from Khimicheskie Volokna, No. 2, pp. 10–12, March–April, 2005.     

Analyses of Multiple Film Cracking in Film/Substrate Systems

Multiple film cracking in a film/substrate system is analyzed in the present study. The system is subjected to residual stresses before loading. A constant displacement rate is applied unidirectionally to stretch the system. An analytical model is developed to derive the stress distribution in the system, and the film-cracking problem is analyzed using both the strength and the energy criteria. The predicted crack spacing as a function of the applied strain is compared with experimental measurements of multiple cracking of SiO _x films with various thicknesses on poly(ethylene terephthalate) substrates. Comparison is also made between the present and other predictions.     

纤维素/壳聚糖复合膜的制备及结构表征

通过氯化1-(2-羟乙基)-3-甲基咪唑离子液体([HeMIM]Cl)溶解微晶纤维素,并与壳聚糖的醋酸溶液混合的方法制备了质量比为2∶1的再生微晶纤维素/壳聚糖复合膜。利用红外光谱、X射线衍射、热重分析、扫描电镜和数码相机照片对复合材料的结构进行表征。IR结果表明再生微晶纤维素与壳聚糖分子之间存在着强烈的氢键作用,且二者相容性较好;XRD、TGA结果表明复合材料中纤维素和壳聚糖有较强的相互作用;SEM结果表明复合材料表面粗糙,比表面积较大,可以作为潜在的生物医用材料。