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排序方式: 共有1382条查询结果,搜索用时 31 毫秒
1.
Gorzkiewicz Krzysztof Mietelski Jerzy Wojciech Kierepko Renata Brudecki Kamil 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1311-1321
Journal of Radioanalytical and Nuclear Chemistry - This paper presents results of the development process of low-background, digital gamma-rays spectrometer equipped with Broad Energy Germanium... 相似文献
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Monika Szufla Aleksandra Choroś Dr. Wojciech Nitek Prof. Dariusz Matoga 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(37):e202200835
By using the strategy of pre-assembly chlorosulfonation applied to a linker precursor, the first sulfonated zirconium metal–organic framework ( JUK-14 ) with two-dimensional (2D) structure, was synthesized. Single-crystal X-ray diffraction reveals that the material is built of Zr6O4(OH)4(COO)8 oxoclusters, doubly 4-connected by angular dicarboxylates, and stacked in layers spaced 1.5 nm apart by the presence of sulfonic groups. JUK-14 exhibits excellent hydrothermal stability, permanent porosity confirmed by gas adsorption studies, and shows high (>10−4 S/cm) and low (<10−8 S/cm) proton conductivity under humidified and anhydrous conditions, respectively. Post-synthesis inclusion of imidazole improves the overall conductivity increasing it to 1.7×10−3 S/cm at 60 °C and 90 % relative humidity, and by 3 orders of magnitude at 160 °C. The combination of 2D porous nature with robustness of zirconium MOFs offers new opportunities for exploration of the material towards energy and environmental applications. 相似文献
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Back Cover: Co‐existence of Two Different α‐Synuclein Oligomers with Different Core Structures Determined by Hydrogen/Deuterium Exchange Mass Spectrometry (Angew. Chem. Int. Ed. 29/2014) 下载免费PDF全文
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Van der Waals equation of state as well as power laws and critical exponent theories are prototypes to study the cubic shape, asymmetries and “flatness” of the vapor–liquid equilibrium curves near the critical point. In this work we study two similar methods to determine the phase curves in analytical form, which differ from each other by simplicity of mathematical calculation. We analyze temperature dependence of the coexistence curves asymptotically close to the vapor–liquid critical point. We explain the novelty of our method with respect to the standard thermodynamic limit discussed in the literature. Therefore we show that the shape of the coexistence curves can strongly influence the accepted value of the critical exponent. The results of theoretical studies have been compared with the ones obtained by experimental methods. 相似文献
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Marcin Kubisiak Karolina Zelga Wojciech Bury Iwona Justyniak Krzysztof Budny-Godlewski Zbigniew Ochal Janusz Lewiński 《Chemical science》2015,6(5):3102-3108
This paper reports a series of comparative experiments on the activity of carbon- and oxygen-centred radical species in a model reaction of the radical addition of THF to imines mediated by a series of zinc alkyl/air reaction systems. The study strongly contradicts the notion that generally R˙ radicals are the initiating species in organic reactions mediated by RnM/air systems, and simultaneously demonstrates that oxygen-centred radical species are the key intermediates responsible for the initiation process. In addition, a new efficient RZn(L)/air initiating system for radical organic reactions exampled by a model reaction of radical addition of THF to imines is developed. Moreover, the isolation and structural characterization of the first zinc alkylperoxide supported by a carboxylate ligand, [Zn4(μ3-OOtBu)3(μ4-O)(O2CEt)3]2, as well as the novel octanuclear zinc oxo(alkoxide) aggregate with entrapped O–THF species, [Zn4(μ4-O)(μ3-2-O–THF)(O2CEt)5]2, provide clear mechanistic signatures for the mode of function of the RZn(O2CR′)/air system. 相似文献
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Kamila Salasinska Monika Borucka Milena Leszczyńska Wojciech Zatorski Maciej Celiński Agnieszka Gajek Joanna Ryszkowska 《Journal of Thermal Analysis and Calorimetry》2017,130(1):131-141
Using one-step method, rigid polyurethane foams were made, modified with developed fire retardant systems containing halogen-free flame retardants and nanofillers in the form of multi-walled carbon nanotubes or nanoscale titanium dioxide. The materials were subjected to a test using a cone calorimeter and smoke-generating chamber, and selected samples were further analyzed via thermogravimetry and oxygen index. Moreover, the products of thermal degradation of selected samples were identified using gas chromatography with mass spectrometer. Conducted flammability tests confirmed the presence of a synergistic effect between the used nanofillers and halogen-free flame retardants. It has been observed that the carbonized layer, the formation of which favored the presence of nanoadditives, inhibits the combustion process. Furthermore, nanofillers influenced favorably reduction in the amount and the number of occurring products of thermal degradation. 相似文献
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Alexander Bendikov Wojciech Cygan Bartosz Trojan 《Stochastic Processes and their Applications》2017,127(10):3268-3290
We consider a random walk which is obtained from the simple random walk by a discrete time version of Bochner’s subordination. We prove that under certain conditions on the subordinator appropriately scaled random walk converges in the Skorohod space to the symmetric -stable process . We also prove asymptotic formula for the transition function of similar to the Pólya’s asymptotic formula for . 相似文献
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Nowadays profitability and efficiency of practical and industrial applications and therefore of material design is becoming a more important issue. Due to different well-known and established approaches for analysis and simulation of complex heterogeneous materials on multiple scales based on numerical homogenisation techniques, development and production of high performance materials (using 3d printers for example) and as a consequence optimisation and design of materials is reality. The objective is to find optimal structures with optimal material distribution under given constraints related to posed problems and tailoring applications to their special requirements. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献