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排序方式: 共有230条查询结果,搜索用时 265 毫秒
11.
Pablo Salcedo-Abraira Sergio M.F.Vilela Artem A.Babaryk Maria Cabrero-Antonino Pedro Gregorio Fabrice Salles Sergio Navalon Hermenegildo Garcia Patricia Horcajada 《Nano Research》2021,14(2):450-457
A novel microporous two-dimensional(2D)Ni-based phosphonate metal-organic framework(MOF;denoted as IEF-13)has been successfully synthesized by a simple and green hydrothermal method and fully characterized using a combination of experimental and computational techniques.Structure resolution by single-crystal X-ray diffraction reveals that IEF-13 crystallizes in the triclinic space group Pi having bi-octahedra nickel nodes and a photo/electroactive tritopic phosphonate ligand.Remarkably,this material exhibits coordinatively unsaturated nickel(II)sites,free-P03H2and-P03H acidic groups,a C02accessible microporosity,and an exceptional thermal and chemical stability.Further,its in-deep optoelectronic characterization evidences a photoresponse suitable for photocatalysis.In this sense,the photocatalytic activity for challenging H2generation and overall water splitting in absence of any co-catalyst using UV-Vis irradiation and simulated sunlight has been evaluated,constituting the first report for a phosphonate-MOF photocatalyst.IEF-13 is able to produce up to 2,200 fimol of H2per gram using methanol as sacrificial agent,exhibiting stability,maintaining its crystal structure and allowing its recycling.Even more,170μmol of H2per gram were produced using IEF-13 as photocatalyst in the absence of any co-catalyst for the overall water splitting,being this reaction limited by the 02reduction.The present work opens new avenues for further optimization of the photocatalytic activity in this type of multifunctional materials. 相似文献
12.
A. S. Kudryavtsev D. A. Artem’eva M. S. Mikhailov 《The Physics of Metals and Metallography》2017,118(8):788-794
The influence of the nitrogen content on the structure and mechanical properties of heat and corrosion resistant 12% Cr martensitic-ferritic steel developed at the Central Research Institute of Structural Materials Prometey has been studied. Steel containing 0.061 wt % nitrogen possesses a high level of mechanical properties. The decrease in the nitrogen content to 0.017 wt % leads to an increase of structurally free ferrite fraction in the steel, a decrease in the density of dislocations, a decrease of structural dispersity and the absence of finely dispersed precipitates of niobium and vanadium nitrides and carbides. As a result, there is a decrease in the strength properties, especially in the heat resistance. 相似文献
13.
A reference model is considered for a magnetic field intended for checking programs and algorithms defining the electromagnetic
field in an electromagnetic flowmeter measurement channel.
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Translated from Izmeritel’naya Tekhnika, No. 4, pp. 39–41, April, 2007. 相似文献
14.
Igor E. Agranovski Oleg V. Pyankov Olga G. Pyankova Artem A. Sergeev Alexander N. Sergeev Maria A. Smetannikova Alexander S. Safatov 《Journal of aerosol science》2010,41(2):161-169
This paper describes a new method for precise determination of viral aerosol lethal dose (ALD50) and reports the results obtained for birds exposed by H5N1 Avian influenza A strain under controlled laboratory conditions. The reported method utilizes our recently developed personal bioaerosol sampler capable of monitoring viable virus concentration in the ambient air. Up to six laboratory animals could be located in a specially designed aerosol chamber and exposed in parallel by an airborne strain of interest to generate the amount of data sufficient for representative statistical analysis. A concentration of viable airborne virus was measured by the personal aerosol samplers directly in the breathing zone of each particular bird. The results show a very low inter-sampler variation used for each particular run, which was confirmed by a single factor ANOVA test undertaken for all six personal samplers involved in each experiment. As was shown, the difference in amount of viruses collected by all samplers during each particular run was not statistically significant. It was found that the ALD50 for approximately 400-g birds exposed to H5N1 Avian influenza A strain A/Chicken/Suzdalka/Nov-11/2005 was around 26.5 FFU (focus forming units). 相似文献
15.
Artem A. Barabanov Nina V. Semikolenova Michail A. Matsko Ljudmila G. Echevskaya Vladimir A. Zakharov 《Polymer》2010,51(15):3354-1654
The effects of polymerization time and temperature on the molecular weight and molecular weight distribution of polyethylene, produced over homogeneous catalyst bis[N-(3-tert-butyl salicylidene)anilinato]zirconium(IV) dichloride tBu-L2ZrCl2/MAO have been studied. The data on the number of active centers (CP) and propagation rate constants (kP) at different polymerization time have been obtained as well. It was found that at a short polymerization time two types of active centers, producing low molecular weight PE (Mw = (4-10) × 103 g mol−1) are formed. The number of these centers was estimated to be 11% of total zirconium complex and their reactivity is very high (the kP value was found to be 54 × 103 L mol−1 s−1 at 35 °C). High initial activity of the catalyst fell with the increase in polymerization time, whereas the polydispersity values of the resulting PE increase due to formation of new centers, producing high molecular weight PE (Mw = (30-1300) × 103 g mol−1). It was found that the decrease in activity is caused by reducing the initial active centers number and lower reactivity of the new-formed centers (kP = 17 × 103 L mol−1 s−1). 相似文献
16.
A. T. Klyuchnikov A. D. Korotaev N. V. Lobov Yu. N. Artem’ev 《Russian Electrical Engineering》2010,81(10):559-562
Mathematical expressions for determining the moments and speeds of the elements of planetary gearboxes are obtained. The possible
modes of the operation of an internal combustion engine (ICE) combined with two electric machines are shown. The relation
between powers of electric machines and the geometrical parameters of the planetary gear is achieved. 相似文献
17.
M. N. Sabodina S. N. Kalmykov K. A. Artem’eva E. V. Zakharova Yu. A. Sapozhnikov 《Radiochemistry》2006,48(5):488-492
Sorption of Cs, Pu(IV), Np(V), and U(VI) with bentonite from solutions was studied. Physicochemical species of radionuclides in the liquid phase were determined, the sorption mechanisms were established, and the influence of bentonite colloids on the behavior of radionuclides was studied. It was shown that Cs is sorbed by the ion-exchange mechanism, whereas the sorption of actinides at pH > 5 is governed by the reaction with surface hydroxy groups of betonite, and at pH < 5 the competing processes are ion exchange and complex formation. Reduction of Np(V) and U(VI) to Np(IV) and U(IV) in the solution with Fe(II) compounds present in the system was proved by the extraction method. Various methods of separating the solid phase were used in studying the dependence of the distribution coefficients of Np and Pu on the ratio of pore water and bentonite; it was shown that Np and Pu are sorbed on bentonite colloids. 相似文献
18.
T. A. Kostereva Yu. N. Panov V. N. Artem’eva N. V. Kukarkina N. A. Nikanorova V. V. Kudryavtsev 《Journal of Engineering Physics and Thermophysics》2005,78(5):948-953
The time change in the melt viscosity of the polyamide composite forming at the final stage a polymer with the structure of
a semi-interpenetrative polymer mesh has been investigated. To impregnate with the composite melt the carbon fiber for forming
carbon-filled plastics, it is necessary to preserve the low viscosity of the melt for a long time. This is achieved by preliminary
heat treatment of the composite and introduction of fullerene into it.
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Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 5, pp. 109–113, September–October, 2005. 相似文献
19.
利用基于扫描相机的荧光寿命成像显微技术研究细胞周期 总被引:2,自引:1,他引:1
利用基于扫描相机的荧光寿命成像显微系统,以细胞周期为模型,研究转染绿色荧光蛋白的HeLa细胞的荧光寿命。结果表明,处于周期内不同进程的细胞的荧光寿命为2.50~3.00 ns。处于分裂期的细胞的荧光寿命在1 h内从2.86 ns下降到2.82 ns;在DNA合成前期的8 h内,荧光寿命从2.82 ns下降到2.78 ns。荧光寿命的差异反映了细胞周期中核浆内大分子浓度的变化,对了解细胞周期的分子机制有一定的意义。 相似文献
20.