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81.
Huimin Xiang Xiaohui Wang Jingyang Wang Yanchun Zhou 《Journal of Raman spectroscopy : JRS》2013,44(3):485-488
Superconductivity of Nb2AlC has been previously reported, but the origin is not clear. In this paper, in situ Raman spectra of Nb2AlC are measured in the temperature range from 80 to 380 K at ambient pressure. The line‐width of E2g (ω1) mode increases with temperature which originates from the anharmonic phonon–phonon scattering. On the contrary the line‐widths of E2g (ω2) and A1g (ω4) modes decrease continuously at elevated temperature. The phenomenon is explained by the electron–phonon coupling. The origin of superconductivity is therefore interpreted by the coupling of Nb 4d electrons with E2g (ω2) and A1g (ω4) phonon modes. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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84.
利用4mol·dm^-^3NaOH提取结合层析柱提纯, 从大豆细胞壁物质(膳食纤维)中分离出PRF6聚合物组分(即木糖葡聚糖)。通过酸水解、酸部分水解、纤维素酶降解和甲基化等分析方法, 借助气相色谱和色质联用等现代仪器, 对该组分的结构特征作了详尽的剖析。结果表明其主链结构是由β(1→4)糖苷键连接的葡聚糖, 主链在6-C位置带有吡喃木糖残基作为侧键, 部分木糖残基在2-C位置还连有阿拉伯呋喃糖或半乳吡喃糖残基。 相似文献
85.
大豆糖蛋白的结构研究 总被引：5，自引：0，他引：5
应用NaClO2-HOAc提取结合层析柱提纯, 从大豆细胞壁物质(膳食纤维)中分离出PRF3纯组分。这是一种富含羟脯氨酸的糖蛋白, 本文对其结构特征作详尽剖析。结果表明, PRF3多糖部分的主链结构是由β(1→4)糖苷键连接的半乳聚糖,主链通过3-C分支点连接由α(1→3)键连的低聚阿拉伯糖侧链, 多糖与多肽之间通过HPr-Ara和Ser-Gal糖苷键连接在一起。 相似文献
86.
3D printing, a rapidly expanding domain of additive manufacturing, enables the fabrication of intricate 3D structures with adjustable fabrication parameters and scalability. Nonetheless, post-fabrication, 3D-printed materials often require an activation step to eliminate non-conductive polymers, a process traditionally achieved through chemical, thermal, or electrochemical methods. These conventional activation techniques, however, suffer from inefficiency and inconsistent results. In this study, a novel chemical-free activation method employing laser treatment is introduced. This innovative technique effectively activates 3D-printed electrodes, which are then evaluated for their photo and electrochemical performance against traditional solvent-activated counterparts. The method not only precisely ablates surplus non-conductive polymers but also exposes and activates the underlying electroactive materials. The 3D-printed electrodes, processed with this single-step laser approach, exhibit a notably low overpotential of ≈505 mV at a current density of −10 mA cm−2 under an illumination wavelength of 365 nm. These electrodes also demonstrate exceptional durability, maintaining stability through >100 000 cycles in energy storage applications. By amalgamating 3D printing with laser processing, the creation of electrodes with complex structures and customizable properties is enabled. This synergy paves the way for streamlined production of such devices in the field of energy conversion and storage. 相似文献
87.
Mahdie Safarpour Shahla Hosseinpour Mahsa Haddad Irani-nezhad Yasin Orooji Alireza Khataee 《Molecules (Basel, Switzerland)》2022,27(24)
In this research work, the Ti2SnC MAX phase (MP) was synthesized via the reactive sintering procedure. The layered and crystalline structure of this MP was verified by SEM, HRTEM, and XRD analyses. This nano-additive was used for improvement of different features of the polyethersulfone (PES) polymeric membranes. The blended membranes containing diverse quantities of the MP (0–1 wt%) were fabricated by a non-solvent-induced phase inversion method. The asymmetric structure of the membranes with small holes in the top layer and coarse finger-like holes and macro-voids in the sublayer was observed by applying SEM analysis. The improvement of the membrane’s hydrophilicity was verified via reducing the contact angle of the membranes from 63.38° to 49.77° (for bare and optimum membranes, respectively). Additionally, in the presence of 0.5 wt% MP, the pure water flux increased from 286 h to 355 L/m2 h. The average roughness of this membrane increased in comparison with the bare membrane, which shows the increase in the filtration-available area. The high separation efficiency of the oil/water emulsion (80%) with an improved flux recovery ratio of 65% was illustrated by the optimum blended membrane. 相似文献
88.
Designing efficient electrocatalysts with low Pt loadings for hydrogen evolution reaction(HER)is urgently required for renewable and sustainable energy conversion.Here,we report a strategy that Pt nanoparticulates are spontaneously immobilized on porous MXene/MAX monolith as HER catalysts by utilizing the redox reaction between Ti3C2Tx MXene and[PtCl4]2 in H2 PtCl6 aqueous solution.By taking advantage of homogeneously distributed Pt nanoparticulates on highly electrically conductive porous Ti3C2Tx/Ti3AlC2 monolith,the as-prepared electrocatalysts show high catalytic performance for hydrogen evolution.Specifically,the binder-free electrocatalysts have Pt loadings as low as 8.9μg/cm^2,with low overpotential of 43 mV at a curre nt density of 10 mA/cm^2 and low Tafel slope that three times lower than porous Ti3C2Tx/Ti3AlC2 without Pt loading.This strategy offers a new approach to constructing ultra-low Pt-loading HER catalysts on the basis of in situ redox reaction between noble metal ions and MXenes. 相似文献
89.
由于Li+电池充电器的充电过程会持续一个小时甚至更长的时间,利用实际负载(即电池)对充电器进行测试将非常耗时。文中介绍了一种简单的Li+电池仿真方法,与采用实际电池进行测试相比,这种方法能够更加方便地测试Li+电池充电器。 相似文献
90.
For problems SAT and MAX SAT, local search algorithms are widely acknowledged as one of the most effective approaches. Most of the local search algorithms are based on the 1-flip neighborhood, which is the set of solutions obtainable by flipping the truth assignment of one variable. In this paper, we consider r-flip neighborhoods for r = 2, 3, and examine their effectiveness by computational experiments. In the accompanying paper, we proposed new implementations of these neighborhoods, and showed that the expected size of 2-flip neighborhood is O(n + m) and that of 3-flip neighborhood is O(m + t
2
n), compared to their original size O(n
2) andO(n
3), respectively, where n is the number of variables, m is the number of clauses and t is the maximum number of appearances of one variable. These are used in this paper under the framework of tabu search and other metaheuristic methods, and compared with other existing algorithms with 1-flip neighborhood. The results exhibit good prospects of larger neighborhoods. 相似文献