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31.
Jaqueline Oliveira de Moraes 《Drying Technology》2018,36(7):830-840
Tape casting is a suitable process for large-scale production of biodegradable films. This study presents a comparison of three drying procedures of starch–cellulose films: i) conduction drying, ii) infrared drying (42.3?W?m?2, higher infrared heating power damaged the films), and iii) conduction-infrared drying. All the drying procedures were performed at approximately 60°C. Drying times from the second and third methods were close to 1?h, half the time observed for conduction drying. Films from the second and third methods showed similar hygroscopicity (0.15?g.?g?1, RH 43%), tensile strength (31.3?MPa, RH 58%), and glass transition temperature (?12.13°C, RH 43%). 相似文献
32.
《Strain》2018,54(4)
The present work focuses on an experimental analysis of different photoelastic extraction methods. An adapted test rig designed in order to evaluate several extraction methods, which come from the literature and 2 new proposed methods. Their comparisons point out dissimilar behaviours between them in an experimental environment. However, some specific cases require the use of most appropriate techniques to minimise the defects influence. Therefore, a specific application of the photoelasticity is presented to illustrate the meaning of the technique used. It mainly focuses on the determination of the residual stresses and their orientation inside photovoltaic crystal silicon wafers. 相似文献
33.
Hassan Al Sabea Lucie Norel Olivier Galangau Thierry Roisnel Olivier Maury Franois Riob Stphane Rigaut 《Advanced functional materials》2020,30(30)
This work describes a class of complex combining three dithienylethene units and a lanthanide ion used as an optical system displaying a double encryption method: i) a colorful code, drawn and erased under UV and visible irradiations respectively, due to coloration and discoloration of the photochromic entities, and ii) a concomitant gradual disappearance and progressive restoration of the associated lanthanide ion luminescence triggered with the same stimuli. The innovation of the system stems from the emission color tunability, i.e., with either a lanthanide ion emitting only in the visible range (Eu3+) or with another lanthanide ion emitting only in the near infrared (NIR) range (Yb3+), therefore observable, or not, to the naked eye. This system is the very first one to achieve efficient repeatable modulation of pure NIR luminescence on photochemical command. Furthermore, it is proven to be highly efficient when embedded in a PDMS polymer opening real opportunities for practical applications as anti‐counterfeiting. 相似文献
34.
《能源学会志》2020,93(6):2362-2370
To facilitate the reuse and recycling of polyvinyl chloride (PVC) to achieve sustainable development and new industrialization, the composition and mechanism of formation of volatiles during the flash pyrolysis of PVC were studied by thermogravimetry-Fourier transform infrared (TG-FTIR) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). TG and derivative thermogravimetry (DTG) analyses indicated two main degradation stages during flash pyrolysis of PVC, namely dehydrochlorination of PVC and decomposition of dechlorinated-PVC. Simultaneously, the FTIR results revealed that the main functional groups in the pyrolysis process were H–Cl, -C-Cl, C–H, CH, and aromatic groups. The relative content of main volatiles was determined by Py-GC/MS, and decreased in the following order: aromatics > alkenes > hydrogen chloride (HCl) > chlorinated hydrocarbons. Specifically, the relative content of aromatics was as high as 76.790–81.809%, while that of HCl was in the range of 3.016–3.096%. The carbon number distribution and the relative content of main products obtained from the flash pyrolysis of PVC at different final temperatures were also analysed. According to the experimental results, the mechanism of formation of the main volatiles based on free-radical reactions was deduced in detail. Therefore, this study provides further details for deepening the understanding of the PVC pyrolysis process. 相似文献
35.
36.
目的 以ZnO/SiO2复合粉体为填料,开展新型热控涂层制备方法研究,提高传统白色热控涂层的紫外反射率, 研制出具有太阳全光谱高反射性能的热控涂层。方法 以硫酸锌和硅酸钠为原料,采用常温化学合成与高温热处理相结合的方法制备ZnO/SiO2复合粉体,通过X射线衍射仪、扫描电子显微镜及紫外可见分光光度计等仪器,对复合粉体的微观结构及光学性能进行表征。然后以ZnO/SiO2复合粉体为填料,以无机硅酸钾为粘结剂,制备了ZnO/SiO2热控涂料,通过不同颜基比和厚度的优化,得到了太阳全光谱(200~ 2600 nm)高反射白色热控涂层的制备方法。结果 研制的ZnO/SiO2复合粉体在紫外波段的反射率均大于88%,与传统ZnO粉体相比具有明显提升。当以无机硅酸钾为粘结剂、颜基比为2:1、喷涂厚度为100~140 μm时,所制备涂层在太阳全光谱呈现高反射特性,此时涂层的太阳吸收比为0.12,红外发射率为0.92。结论 ZnO/SiO2热控涂层具有优异的热控性能,与传统白色热控涂层相比具有更低的吸收比,同时在太阳全光谱具有高反射特性,可以满足新一代大功率卫星长寿命和高效散热的技术需求。 相似文献
37.
设计了一种适用于复杂条件下实施井下温度探测的射频式红外温度传感器。借助于光学系统、光电探测器实时感应井下温度并提取温度信号,同时在DC-DC电源隔离模块中实施EMI滤波以抗电磁干扰,处理后的信号经过A/D转换、运算器放大后显示在LCD上,实施读取数据并记录在传感器的存储片上,实现了矿井复合灾害条件下的温度测试,测试精度控制在±2%。 相似文献
38.
39.
Near- and short-wave IR emission spectra of printed cotton/nylon blend fabrics coated with inorganic compounds in order to tune their diffuse reflectance behavior to the ones with woodland and desert backgrounds are investigated. In this regard, cotton/nylon blend fabrics printed with a four-color digital pattern were used as the substrate, and different concentrations of zirconium and cerium dioxide (ZrO2 and CeO2) with and without citric acid as a cross-linker were loaded on these fabrics using the pad-dry-cure method. The diffuse reflectance of the coated fabrics with various concentrations of nanoparticles and a cross-linker was first measured by near-infrared (NIR) diffuse reflectance spectroscopy (DRS). Then, fabrics with an optimum concentration of nanoparticles and appropriate reflectivity profiles similar to woodland and desert were investigated by field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), washing, and rubbing fastness properties. In general, NIR and short-wave infrared (SWIR) reflectance of fabrics coated with ZrO2 and CeO2 nanoparticles in range of 1% to 1.5% (w/v [%]) was suitable for matching with different environments. According to the findings obtained from the durability test, it was concluded that the washing fastness of the treated fabrics with CeO2 nanoparticles was excellent in both environments. FE-SEM images of the treated fabrics containing ZrO2 and CeO2 indicated that the presence of nanoparticles on the surface of fabrics in woodland patterns was greater than the desert ones. However, the coated fabrics with CeO2 and citric acid in the woodland pattern have shown better dispersion with a mean particle size of 30 to 60 nm. 相似文献
40.
《International Journal of Hydrogen Energy》2019,44(10):4698-4706
Polyaniline is a typical conducting polymer with high migration electron rate, good stability, eco-friendly properties, and high absorption coefficients for visible light. In the present study, polyaniline decorated Pt@TiO2 for visible light-driven H2 generation is reported for the first time. The above-mentioned nanocomposite is prepared through a simple oxidative-polymerization and characterized by infrared spectroscopy, transmission electron microscopy, X–ray diffraction, thermogravimetric analysis, and ultraviolet–visible diffuse reflectance spectra. Polyaniline modification improves the absorption of the nanocomposite in visible light region via a photosensitization effect similar to dye–sensitization but does not influence the crystal structure and size of Pt@TiO2. The polyaniline modified Pt@TiO2 exhibits a remarkable visible light activity (61.8 μmol h−1 g−1) and good stability for H2 generation (with an average apparent quantum yield of 10.1%) with thioglycolic acid as an electron donor. This work provides new insights into using conducting polymers, including polyaniline, as a sensitizer to modify Pt@TiO2 for visible-light hydrogen generation. 相似文献