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排序方式: 共有136条查询结果,搜索用时 15 毫秒
1.
Shengmei Chen Yiran Ying Shengnan Wang Longtao Ma Haitao Huang Xiaoqi Wang Xu Jin Shengchi Bai Prof. Chunyi Zhi 《Angewandte Chemie (International ed. in English)》2023,62(19):e202301467
Though massive efforts have been devoted to exploring Br-based batteries, the highly soluble Br2/Br3− species causing rigorous “shuttle effect”, leads to severe self-discharge and low Coulombic efficiency. Conventionally, quaternary ammonium salts such as methyl ethyl morpholinium bromide (MEMBr) and tetrapropylammonium bromide (TPABr) are used to fix Br2 and Br3−, but they occupy the mass and volume of battery without capacity contribution. Here, we report an all-active solid interhalogen compound, IBr, as a cathode to address the above challenges, in which the oxidized Br0 is fixed by iodine (I), thoroughly eliminating cross-diffusing Br2/Br3− species during the whole charging and discharging process. The Zn||IBr battery delivers remarkably high energy density of 385.8 Wh kg−1, which is higher than those of I2, MEMBr3, and TPABr3 cathodes. Our work provides new approaches to achieve active solid interhalogen chemistry for high-energy electrochemical energy storage devices. 相似文献
2.
《International Journal of Plasticity》2006,22(4):654-684
The intent of this work is to derive a physically motivated mathematical form for the gradient plasticity that can be used to interpret the size effects observed experimentally. The step of translating from the dislocation-based mechanics to a continuum formulation is explored. This paper addresses a possible, yet simple, link between the Taylor’s model of dislocation hardening and the strain gradient plasticity. Evolution equations for the densities of statistically stored dislocations and geometrically necessary dislocations are used to establish this linkage. The dislocation processes of generation, motion, immobilization, recovery, and annihilation are considered in which the geometric obstacles contribute to the storage of statistical dislocations. As a result, a physically sound relation for the material length scale parameter is obtained as a function of the course of plastic deformation, grain size, and a set of macroscopic and microscopic physical parameters. Comparisons are made of this theory with experiments on micro-torsion, micro-bending, and micro-indentation size effects. 相似文献
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This paper presents a modified Artificial Bee Colony algorithm for structural damage identification. Meanwhile, the effect of temperature variation is considered and the change of temperature will lead to the alteration of Young's modulus of material. A novel objective function is proposed as the combinations of the partial mode shape curvature data, alterations of natural frequencies, and a sparse penalty term. Such an objective is found to be sensitive to structural damage while not sensitive to environmental effects. On the other hand, To render the standard Artificial Bee Colony algorithm more powerful and robustness, two local search strategies are introduced into the employed and onlooker bee phase of the Artificial Bee Colony algorithm, respectively. Two numerical examples and a laboratory verification are employed to verify the efficiency and advantage of the proposed algorithm. The final results show that the present algorithm could yield more satisfactory identification results compared with other state-of-the-art evolutionary algorithms, even high-level noise and temperature variation are considered; and the proposed novel objective function is more sensitive to structural damages, compared with the traditional mode-shape-based objective function. 相似文献
5.
Current–voltage (J–V) characteristics of epitaxial hetero-junctions composed of Pr0.7Ca0.3MnO3 and Nb:SrTiO3 were studied under forward and reversed bias conditions. Detailed analysis showed that the J–V characteristics of these heterojunctions can be well-fitted by the thermally-assisted tunnelling model. While the dielectric constant of Nb:SrTiO3 extracted under the forward bias was about one order of magnitude smaller than that of bulk SrTiO3, the value obtained under reverse bias was very close to that of the bulk SrTiO3. The result can be explained by the existence of an interface layer on the Nb:SrTiO3 substrate with a smaller effective dielectric constant. The current finding suggested that the properties of interface layer should be taken into account in order to accurately simulate the J–V characteristics of such heterojunctions. 相似文献
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7.
A. Hossain A.E. Bolotnikov G.S. Camarda Y. Cui G. Yang K-H. Kim R. Gul L. Xu R.B. James 《Journal of Crystal Growth》2010,312(11):1795-1799
We explored some unique defects in a batch of cadmium zinc telluride (CdZnTe) crystals, along with dislocations and Te-rich decorated features, revealed by chemical etching. We extensively investigated these distinctive imperfections in the crystals to identify their origin, dimensions, and distribution in the bulk material. We estimated that these features ranged from 50 to 500 μm in diameter, and their depth was about ∼300 μm. The density of these features ranged between 2×102 and 1×103 per cm3. We elaborated a model of them and projected their effect on charge collection and spectral response. In addition, we fabricated detectors with these defective crystals and acquired fine details of charge-transport phenomena over the detectors’ volume using a high-spatial resolution (25 μm) X-ray response mapping technique. We related the results to better understand the defects and their influence on the charge-transport properties of the devices. The role of the defects was identified by correlating their signatures with the findings from our theoretical model and our experimental data. 相似文献
8.
《Arabian Journal of Chemistry》2022,15(3):103689
Bi2S3/g-C3N4 (BSCN) samples with different mass ratios of CN to BS were prepared by a facile and practicable hydrothermal method with 2D g-C3N4 nanosheets (CN). The microscopic morphology and structure of pure CN, BS and BSCN were measured by multiple testing methods. Analysis results show that the BSCN was prepared successfully, and the Bi2S3 nanoparticles closely and uniformly adhered to the surface of CN with sheet-like structure. The introduction of Bi2S3 did not change the structure of the CN. The results of the ultraviolet–visible spectroscopic analysis, photoluminescence spectra and electrochemical performance indicated that BSCN showed superior visible-light response compared with CN, and the separation and transfer efficiency of photogenerated carriers was significantly improved. With the decrease of mass ratio of CN/BS, the photocatalytic activity of BSCN initially increased and then decreased for 20 ppm of Rhodamine B solution (RhB), and the Bi2S3/g-C3N4-B with a mass ratio of 8:1 for CN to BS showed optimal photocatalytic performance (98.98%). Furthermore, the Bi2S3/g-C3N4-B exhibited apparent degradation effects (1.021 x10-2, 0.879 x10-2 and 0.793 x10-2 min?1) to three kinds of antibiotics (tetracycline, ciprofloxacin, and oxytetracycline). The BSCN samples still maintained higher degradation efficiency after five cycles of degradation to tetracycline. The capture experiments and the electron spin resonance (ESR) spectra analysis indicated that the h+ and ·O2? played a major role, and ·OH played secondary role during the photocatalytic reaction. 相似文献
9.
针对复杂环境下多通道声信号分离问题,提出稀疏正交联合约束多通道非负矩阵分解声信号分离方法。首先设计基于多通道扩展坂仓斋藤(Itakura-Saito,IS)散度的稀疏正交联合约束项构造代价函数,给出信号稀疏和信号正交约束辅助函数,实现代价函数最小化求解。然后通过迭代更新规则设计,得到稀疏正交优化的多通道非负矩阵分解基矩阵和系数矩阵,讨论了稀疏正交约束对基矩阵和系数矩阵稀疏性与连续性影响。最后基于多通道信号空间特性,进行了非负矩阵分解基聚类以获得多通道非负矩阵分解声信号的分离结果。双通道音频数据与四通道声学目标分离实验数据测试表明,对音频数据,所提算法在性能指标信号失真比(SDR)上提高了0.84 dB,对于直升机声源数据,所提算法在SDR上提高了4.53 dB。 相似文献
10.
《Proceedings of the Combustion Institute》2023,39(4):4299-4307
Co-firing ammonia (NH3) and hydrogen (H2) or H2-rich fuel and partially cracking NH3 are promising non-carbon combustion techniques for gas turbines and marine engines, raising a growing need to understand the interactions of H2 and nitric oxide (NO) as well as the non-hydrocarbon nitrogen oxides (NOX) reduction mechanism under flame conditions. In this work, the outwardly propagating spherical flame method was used to investigate the laminar flame propagation of H2/NO and H2/NO/nitrogen (N2) mixtures at initial pressure (Pu) of 2 atm, initial temperature (Tu) of 298 K and equivalence ratios of 0.2-1.4. The laminar burning velocities (LBVs) of H2/NO mixtures are generally 5-10 times lower than those of H2/air mixtures, while the dilution of N2 can dramatically inhibit the laminar flame propagation. A kinetic model of H2/NO combustion was constructed and validated against the new data in this work and other types of experimental data in literature. The modeling analyses reveal that NO+H=N+OH becomes the most important chain-branching reaction in H2/NO reaction system, while the LBV data of H2/NO mixtures in this work can provide highly sensitive validation targets for the kinetics in H2 and NO interactions. Furthermore, the NO reduction to N2 mainly proceeds through NO+N=N2+O under various H2/NO ratios, and NO+O=N+O2 is found to have a significant contribution to NO reduction under NO-rich conditions. 相似文献