Impacts of spectral variations in multiwavelength excitation method on measurements of fluorescently whitened papers

The multiwavelength excitation (MWE) method for measuring the colorimetric properties of fluorescent whitening agent (FWA)‐treated specimens illuminated by a standard daylight illuminant computationally approximates not the spectral power distribution (SPD) of the illuminant but the luminescent SPD excited thereby by a weighted sum of the luminescent SPDs excited by a few different narrow‐band illuminations. The weights are optimized for the actual SPDs of those illuminations and the bispectral luminescent radiance factors of typical FWA‐treated paper specimens. Since the latter is invariant among instruments once provided as the common numerical data, the variations of the narrow‐band SPDs give major impacts to the reproducibility of this method. The weights optimized for the varied SPDs, however, mitigate the impacts. For investigating how they impact, one basic illumination system and its 16 simple variation systems were built virtually. The basic system consists of three narrow‐band LEDs and one blue‐excited white LED, whereas the individual simple variation system has either the peak wavelength or spectral width of one of the four LEDs (including the blue LED in the white LED) varied. With those systems, seven FWA‐treated papers with the known bispectral radiance factors were measured computationally by simulating the procedure of the MWE method. The differences in the colorimetric values measured with the simple variation systems from those with the basic system are far below the just noticeable difference, which indicates that the MWE method can be a practical solution for better reproducibility in measuring FWA‐treated papers.     

Highly efficient photocatalytic activity and mechanism of novel Er3+ and Tb3+ co-doped BiOBr/ g-C3N5 towards sulfamethoxazole degradation

Bismuth oxyhalides (BiOX (X = Cl, Br, I) are considered to be an important p-type semiconductors in the photocatalysis applications. In particular, tetragonal BiOBr is considered as a stable photocatalyst due to its resilient absorption in the visible region with an band gap energy of 2.8 eV. In the meantime, lanthanide ions (with 3+ oxidation state) implies as conversion catalyst gained huge impact and remain a serious topic in materials chemistry. Here we synthesized upconversion photocatalyst mainly consists of BiOBr with the Er ³⁺ and Tb ³⁺ ions along with low band gap g-C₃N₅ for the improved photocatalytic performances. The synthesized Er³⁺/Tb³⁺@BiOBr-g-C₃N₅ heterojunction was systematically characterized by XRD, and FT-IR for the confirmation of the composite and their morphology were analysed with FESEM and HR-TEM analysis which revealed that the sheets of g-C₃N₅ were decorated by Er³⁺/Tb³⁺ loaded BiOBr microspheres. The XPS analysis confirmed the suitable oxidation state of all the individual elements existing in the composite. As the UV-DRS analysis showed that the band gap of the Er³⁺/Tb³⁺ BiOBr-gC₃N₅ heterojunction was narrowed to 2.64 eV. To evaluate the photocatalytic efficiency of the synthesized g-C₃N₅, Er³⁺/Tb³⁺@BiOBr and Er³⁺/Tb³⁺@BiOBr-gC₃N₅ heterojunction under the simulated visible light irradiation source towards the aqueous sulfamethoxazole degradation. The Er³⁺/Tb³⁺@BiOBr-gC₃N₅ heterojunction shows maximum degradation efficiency of 94.2% after 60 min of visible light irradiation whereas the pure g-C₃N₅ provided about 43.8% and Er³⁺/Tb³⁺@BiOBr implies 55.2% degradation efficiency. The plausible degradation mechanism of pollutant removal was proposed.     

Surface modifications of activated carbon by gamma irradiation

Four commercial activated carbons with different chemical and textural characteristics were modified by gamma irradiation under five different conditions: irradiated in absence of water, in presence of ultrapure water, in ultrapure water at pH = 1.0 and 1000 mg L⁻¹ Cl⁻, in ultrapure water at pH = 7.5 and 1000 mg L⁻¹ Br⁻, and in ultrapure water at pH = 12.5 and 1000 mg L⁻¹ NO₃⁻. Changes in surface chemistry were studied by X-ray photoelectron spectroscopy; pH of point of zero charge, total acidic groups and total basic groups, which were determined by assessment with HCl and NaOH; and textural changes were determined by obtaining the corresponding adsorption isotherms of N₂ and CO₂. Outcomes show that the activated carbon surface chemistry can be modified by gamma irradiation and that the changes depend on the irradiation conditions. Modifications in the sp² hybridization of the surface carbons suggest that the irradiated carbons undergo graphitization. Measurements of structural parameters indicate that the irradiation treatment does not modify the textural properties of the carbons. Finally, studies of pristine and irradiated activated carbons using diffuse reflectance spectroscopy with the Kubelka–Munk function revealed a reduction in band gap energy in the irradiated carbons associated with an increase in sp² hybridization of the carbon atoms.     

（100）应变对正交相Ca2P0.25Si0.75能带结构及光学性质的影响

采用第一性原理赝势平面波方法对（100）应变下正交相Ca2P0.25Si0.75的能带结构及光学性质进行模拟计算.计算结果表明：（100）面在晶格发生100％～116％张应变时,带隙随着应变增加而减小;在晶格发生96％～100％压应变时,带隙随着张应变的增加而增加;88％～96％压应变时,带隙随着压应变的增加而减小;当压应变大于88％后转变为间接带半导体.当施加应变后光学性质发生显著的变化：随着压应变的增加静态介电常数、折射率逐渐减小,张应变则反之.施加压应变反射向低能方向偏移,施加张应变反射向高能方向偏移,但施加应变对反射区域的影响不显著.施压应变吸收谱、光电导率的变化与介电函数和折射率相反.综上所述,应变可以改变Ca2P0.25Si0.75的电子结构和光学常数,是调节Ca2P0.25Si0.75光电传输性能的有效手段.     

Fe掺BaZrS3磁性半导体的制备与研究

硫族钙钛矿是一类新兴的半导体功能材料,具有独特的电子结构与光电性质。本文采用溶胶-凝胶法结合化学气相反应的方法制备了硫族钙钛矿BaZrS₃纳米结构,并且借助掺杂的方法获得了BaZr_1-xFe_xS₃磁性半导体,并对其结构和光、磁学等性能进行研究。结果表明,对氧化物钙钛矿BaZrO₃进行硫化处理,即用同族的S元素替代O元素,样品仍然可以表现出钙钛矿结构,而且硫化处理可以起到降低带隙宽度的作用。同时用具有局域磁矩的3d过渡族金属元素,如Fe进行钙钛矿B位阳离子掺杂,通过控制Fe的掺杂量同样可以系统地调控样品的带隙宽度,而且对于BaZr_99.7Fe_0.03S₃和BaZr_99.5Fe_0.05S₃样品表现出了室温铁磁性。     

Effects of Radiographic Contrast Media on the Micromorphology of the Junctional Complex of Erythrocytes Visualized by Immunocytology

Effects of radiographic contrast media (RCM) application were demonstrated in vitro and in vivo where the injection of RCM into the A. axillaris of patients with coronary artery disease was followed by a significant and RCM-dependent decrease of erythrocyte velocity in downstream skin capillaries. Another study in pigs revealed that the deceleration of erythrocytes coincided with a significant reduction of the oxygen partial pressure in the myocardium—supplied by the left coronary artery—after the administration of RCM into this artery. Further reports showed RCM dependent alterations of erythrocytes like echinocyte formation and exocytosis, sequestration of actin or band 3 and the buckling of endothelial cells coinciding with a formation of interendothelial fenestrations leading to areas devoid of endothelial cells. Key to morphological alterations of erythrocytes is the membrane cytoskeleton, which is linked to the band 3 in the erythrocyte membrane via the junctional complex. Fundamental observations regarding the cell biological and biochemical aspects of the structure and function of the cell membrane and the membrane cytoskeleton of erythrocytes have been reported. This review focuses on recent results gained, e.g., by advanced confocal laser scanning microscopy of different double-stained structural elements of the erythrocyte membrane cytoskeleton.     

广吸力范围内非饱和粉土动力变形特性

以非饱和粉土为研究对象,利用饱和盐溶液蒸汽平衡法和吸力可控的动三轴仪进行动力变形试验,得到了广吸力范围内非饱和粉土试样在净围压和吸力基本不变条件下的骨架曲线、动弹性模量和阻尼比,研究了吸力对非饱和粉土动力变形特性的影响。结果表明,在同一净围压下,非饱和粉土试样的骨架曲线和动弹性模量随着吸力增大而提高,而阻尼比随着吸力增大而减小。此外,随着试样的水力状态从边界效应区到过渡区再到残余区的变化,非饱和粉土试样的骨架曲线和动弹性模量的提高幅度逐渐减小,而阻尼比减小的趋势显著,动弹性模量随应变的衰减率随着吸力的增大而减小。     

打造中国的京剧剧场:梅兰芳大剧院创作随笔之一

文章在充分了解中国的国粹京剧演出的特点及特色的基础上,对京剧剧场品质的定位有了新的深入的理解,尝试对演出的载体——剧场本身作一些变革和创新,以适应京剧的传承,发展及开拓。     

无锡体育会展中心大跨度钢管桁架安装技术

从构件制作、吊机道路、双机抬吊同步控制、支座就位、现场焊接、高空拼接等方面介绍了无锡体育会展中心百米跨度倒三角形钢管桁架的安装技术,统计汇总工期进展和质量检测等相关数据。