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991.
Summary The effect of radiation on the mechanical behaviour of the crosslinked copolymer of maleic anhydride and styrene containing photochromic azo groups was investigated. The analysis of results of the observed photomechanical conversion proved a considerable influence of the thermal effect in addition to the effect of photoisomerization of the photochrome. The interpretation of some photomechanical experiments described earlier may be obscured by a rise in temperature caused by the absorption of radiation. 相似文献
992.
Vladimir A. Blagojević Dušan M. Minić Tomáš Žák Dragica M. Minić 《Intermetallics》2011,19(12):1780-1785
Correlation between hardness of amorphous Fe75Ni2Si8B13C2 alloy and thermally induced structural transformations has been investigated by measuring microhardness in a series of samples heated at different temperatures from 25 to 1000 °C. The alloy has a relatively high hardness in the amorphous state, due to its chemical composition involving silicon, boron and carbon. As the alloy begins to crystallize, microhardness increased and reached a plateau in 500–650 °C temperature region, due to formation composite structure involving the small nanocrystals of α-Fe(Si) and Fe2B phases dispersed in the amorphous matrix. After treatment at higher temperatures, the nanocomposite structure is replaced by a more granulated structure, leading to decline in microhardness. 相似文献
993.
Michael Stöger-Pollach Krýstina Bukvišova Keanu Zenz Leo Stöger Ze Scales 《Journal of microscopy》2024,293(3):138-145
Since semiconductor structures are becoming smaller and smaller, the examination methods must also take this development into account. Optical methods have long reached their limits here, but small dimensions are also a challenge for electron beam techniques, especially when it comes to determining optical properties. In this paper, electron microscopic methods of investigating optical properties are discussed. Special attention is given to the physical limits and how to deal with them. We will cover electron energy loss spectrometry as well as cathodoluminescence spectrometry. We pay special attention to inelastic delocalisation, radiation damage, the Čerenkov effect, interference effects of optical excitations and higher diffraction orders on a grating analyser for the cathodoluminescence signal. 相似文献
994.
库尔勒香梨作为新疆维吾尔自治区的特色农产品,因其肉质柔嫩、味道甜美及香气独特而而深受人们的广泛喜爱。但在采摘后的储存与运输阶段,这种梨类果品常常面临风味损失严重的问题,特别是在贮藏和运输过程中其标志性的香气损失显著。因此,全面了解库尔勒香梨中特征风味成分对于提高其风味品质有着至关重要的作用。本文旨在通过详细分析库尔勒香梨的特征风味成分及其形成机制,来探索其品质变化的主要原因,并与其他水果及不同品种的香梨品种进行风味对比,以揭示其独特的风味特性。此外,本文还探讨了影响库尔勒香梨风味的主要因素,旨在为库尔勒香梨的品质提升与市场竞争力增强提供科学依据,进而推动梨果产业的繁荣与可持续发展,提升果品在市场上的竞争力。 相似文献
995.
Dr. Maroš Bella Dr. Monika Poláková Dr. Vladimír Puchart 《Chembiochem : a European journal of chemical biology》2023,24(9):e202200743
A chemical synthesis of two novel phenyl glycosides of trisaccharides related to acetylarabinoxylan is described. The trisaccharides bear acetyl and arabinofuranosyl moieties at the non-reducing-end xylopyranosyl residue, which is substituted at positions 2 and 3. Both compounds were treated with various xylan deacetylases classified in different carbohydrate esterase (CE) families and significant differences between the families were found. While the arabinosylation hampers deacetylation by CE2-CE5 and CE12 family members, both epitopes are deesterified by CE1 and in particular CE6 enzymes. The 3-O-acetylated 2-O-arabinosylated compound is also processed by CE7 and majority of CE16 esterases, but not by a hitherto non-classified Flavobacterium johnsoniae acetylxylan esterase. The data suggests that a slow deesterification of the 2-O-acetylated 3-O-arabinosylated compound may be due to the acetyl group migration followed by deacetylation of this migration product. 相似文献
996.
Martinia Glogar Tanja Pušić Veronika Lovreškov Tea Kaurin Ana Sutlović 《Coloration Technology》2023,139(2):190-199
The vat dyeing process of specific fabrics with protective, inherently fire retardant properties that have a high content of aramid fibres in their composition, is presented. The research was performed on fabric samples that differ in raw material composition and aramid content. The samples were dyed in raw form (group 1) as well as after pretreatment with alkaline scouring (group 2). Measured limiting oxygen index (LOI) values showed that the selected fabrics meet the properties of inherently fire retardant fabrics. Dyeing was performed with Indanthren® Olive Green HB (manufactured by DyStar) vat dye, in exhaustion process, with a bath ratio of 1:30. The dye concentration was 3%, and sodium-hydrosulphite (Na2S2O4) was used as a reducing agent. The colouristic analyses were performed based on spectrophotometric measurement and results interpretation according to CIELab system. The evaluation of primary tactile properties was performed which show an increase of smoothness and softness after scouring and dyeing. Also, wash fastness as well as light fastness tests have shown satisfactory fastness properties. 相似文献
997.
Michele De Bastiani Rawan Jalmood Jiang Liu Christina Ossig Aleš Vlk Karol Vegso Maxime Babics Furkan H. Isikgor Anand S. Selvin Randi Azmi Esma Ugur Swarnendu Banerjee Alessandro J. Mirabelli Erkan Aydin Thomas G. Allen Atteq Ur Rehman Emmanuel Van Kerschaver Peter Siffalovic Michael E. Stuckelberger Martin Ledinsky Stefaan De Wolf 《Advanced functional materials》2023,33(4):2205557
Textured silicon wafers used in silicon solar cell manufacturing offer superior light trapping, which is a critical enabler for high-performance photovoltaics. A similar optical benefit can be obtained in monolithic perovskite/silicon tandem solar cells, enhancing the current output of the silicon bottom cell. Yet, such complex silicon surfaces may affect the structural and optoelectronic properties of the overlying perovskite films. Here, through extensive characterization based on optical and microstructural spectroscopy, it is found that the main effect of such substrate morphology lies in an altering of the photoluminescence response of the perovskite, which is associated with thickness variations of the perovskite, rather than lattice strain or compositional changes. With this understanding, the design of high-performance perovskite/silicon tandems is rationalized, yielding certified power conversion efficiencies of >28%. 相似文献
998.
M.Sc. Martin Rettinger M.Sc. André Prziwarzinski M.Sc. Maximilian Meyer M.Sc. Lothar Kolbeck M.Arch. Zlata Tošić Dr.-Ing. Alex Hückler Prof. Dr.-Ing. Daniel Lordick Prof. Dr.-Ing. André Borrmann Prof. Dr.-Ing. Michael Haist Prof. Dr.-Ing. Ludger Lohaus Prof. Dr. sc. techn. Mike Schlaich 《Beton- und Stahlbetonbau》2023,118(11):803-814
Modular footbridges made of serially prefabricated concrete elements – Designs from DFG Priority Programme 2187 Modular building structures enable serial and automated production of prefabricated elements, which can be produced in a controlled manner in a precast concrete plant and then assembled on the construction site in a short time. This allows manufacturing processes to be optimised and new technologies of automated and robot-assisted production to be used. Off-site production reduces noise, dust and traffic at construction sites, and the rationalisation of processes in the precast concrete plant can minimise offcuts and waste, thus saving resources. In addition, high-performance materials can be processed with high precision in an environment protected from the weather, so that their properties are optimally utilised and a high and consistent quality is achieved. From the design engineer, modular construction requires a comprehensive understanding and consideration of manufacturing processes as well as careful planning of all joints of the structure. The design team is faced with the challenge of designing a functional, durable and aesthetically appealing structure despite the demands of modularisation, rationalisation and production. In the design studies presented in this paper, the authors meet this challenge by applying technologies from current research projects in modular concrete construction to a consistent design scenario of a pedestrian bridge. 相似文献
999.
I. Labaj P. Skalková I. Kopal J. Vršková M. Harničárová J. Valíček P. Boško J. Dobrovská 《Materialwissenschaft und Werkstofftechnik》2023,54(4):429-440
The current trend of greening production is increasingly bringing to the fore alternative types of fillers, such as biofillers, which are obtained from renewable sources or waste [1, 2]. Unfortunately, biofillers cannot be used as majority fillers due to their incompatibility with elastomer matrices and high biodegradability susceptibility [3, 4]. Therefore, the way to their efficient industrial use leads through supplementary fillers to the commonly used inorganic fillers and the partial replacement of these fillers in the blend. The influence of Chitosan as the majority filler has been investigated and its combination with carbon black filler on the elastomeric matrix of natural rubber was investigated in the presented work. The results were compared with natural rubber blends filled exclusively with carbon black. Natural rubber blends with different content of Chitosan and carbon black and their various combinations were subjected to the determination of vulcanization parameters, mechanical properties before and after thermo-oxidative aging, and scanning electron microscopy. Although the scanning electron microscopy analysis confirmed the expected negative impact of Chitosan as the majority filler on the tensile properties of the vulcanizate, its significant impact on the main vulcanization parameters such as scorch time and optimal vulcanization time was also demonstrated. In the case of blends with a combination of carbon black and Chitosan, it has been shown that Chitosan, in addition to the filler function, also acts as an antioxidant agent through its functional groups, limiting the process of degradation of mechanical properties of natural rubber blends due to their thermo-oxidative aging. It can be concluded that precisely because of its antioxidant and anti-degradation effects, Chitosan can be, in addition to carbon black filler, an excellent additional filler for elastomeric blends. 相似文献
1000.
Christian Massino Cornelia Wetzker Ondřej Balvin Tomáš Bartonicka Jana Kremenova Markéta Sasinkova Oliver Otti Klaus Reinhardt 《Microscopy research and technique》2022,85(1):398-411
Sperm metabolism is fundamental to sperm motility and male fertility. Its measurement is still in its infancy, and recommendations do not exist as to whether or how to standardize laboratory procedures. Here, using the sperm of an insect, the common bedbug, Cimex lectularius, we demonstrate that standardization of sperm metabolism is required with respect to the artificial sperm storage medium and a natural medium, the seminal fluid. We used fluorescence lifetime imaging microscopy (FLIM) in combination with time-correlated single-photon counting (TCSPC) to quantify sperm metabolism based on the fluorescent properties of autofluorescent coenzymes, NAD(P)H and flavin adenine dinucleotide. Autofluorescence lifetimes (decay times) differ for the free and protein-bound state of the co-enzymes, and their relative contributions to the lifetime signal serve to characterize the metabolic state of cells. We found that artificial storage medium and seminal fluid separately, and additively, affected sperm metabolism. In a medium containing sugars and amino acids (Grace's Insect medium), sperm showed increased glycolysis compared with a commonly used storage medium, phosphate-buffered saline (PBS). Adding seminal fluid to the sperm additionally increased oxidative phosphorylation, likely reflecting increased energy production of sperm during activation. Our study provides a protocol to measure sperm metabolism independently from motility, stresses that protocol standardizations for sperm measurements should be implemented and, for the first time, demonstrates that seminal fluid alters sperm metabolism. Equivalent protocol standardizations should be imposed on metabolic investigations of human sperm samples. 相似文献