排序方式: 共有46条查询结果,搜索用时 15 毫秒
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Qiang Fu Xianjie Wang Jiecai Han Jun Zhong Tongrui Zhang Tai Yao Chengyan Xu Tangling Gao Shibo Xi Ce Liang Lingling Xu Ping Xu Bo Song 《Angewandte Chemie (International ed. in English)》2021,60(1):259-267
To ensure sustainable hydrogen production by water electrolysis, robust, earth‐abundant, and high‐efficient electrocatalysts are required. Constructing a hybrid system could lead to further improvement in electrocatalytic activity. Interface engineering in composite catalysts is thus critical to determine the performance, and the phase‐junction interface should improve the catalytic activity. Here, we show that nickel diphosphide phase junction (c‐NiP2/m‐NiP2) is an effective electrocatalyst for hydrogen production in alkaline media. The overpotential (at 10 mA cm?2) for NiP2‐650 (c/m) in alkaline media could be significantly reduced by 26 % and 96 % compared with c‐NiP2 and m‐NiP2, respectively. The enhancement of catalytic activity should be attributed to the strong water dissociation ability and the rearrangement of electrons around the phase junction, which markedly improved the Volmer step and benefited the reduction process of adsorbed protons. 相似文献
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Xinghong Zhang Lin Xu Wenbo Han Ling Weng Jiecai Han Shanyi Du 《Solid State Sciences》2009,11(1):156-161
Hot-pressed zirconium diboride (ZrB2) matrix composites containing 0–30 vol% silicon carbide (SiC) whiskers have been investigated to determine the effect of composition (i.e. amount of SiC whiskers) on the microstructure, mechanical properties and thermal properties. With increasing SiC whisker volume contents, the flexural strength and fracture toughness of the composites were improved compared to those of monolithic ZrB2. Flexural strength increased from 629 MPa for pure ZrB2 to 767 MPa for ZrB2–30 vol%SiCw. Likewise, fracture toughness ranged from 5.4 to 7.1 MPa m1/2 over the same composition range. Specific heat capacity increased with SiC whisker addition, while thermal diffusivity and thermal conductivity decreased slightly with the increase of SiC whisker content. 相似文献
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A comprehensive treatment of fracture of functionally graded materials (FGMs) is provided. It is assumed that the material
properties depend only on the coordinate perpendicular to the crack surfaces and vary continuously along the crack faces.
By using a laminated composite plate model to simulate the material non-homogeneity, an algorithm for solving the system based
on Laplace transform and Fourier transform techniques is presented. Unlike earlier studies that considered certain assumed
property distributions and a single crack problem, the current investigation studies multiple crack problem in the FGMs with
arbitrarily varying material properties. Transient thermal stresses are presented.
Project supported by the National Natural Science Foundation of China (Nos 10102004 and 19902003). 相似文献
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含夹杂和微裂纹复合材料的损伤演化和分析 总被引:3,自引:0,他引:3
利用细观力学的Eshelby和Mori-Tanaka理论,考虑纤维和微裂纹之间的相互作用,研究了定向分布微裂纹的演化规律及其对材料力学性能的影响,分析了纤维体积份数,弹性系数、微裂纹密度,纤维不同取向与基体开裂强度之间的变化关系,并给出了许多有意义的结论。 相似文献
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General coupled solution of anisotropic piezoelectric materials with an elliptic inclusion 总被引:1,自引:0,他引:1
In this investigation, the Stroh formalism is used to develop a general solution for an infinite, anisotropic piezoelectric
medium with an elliptic inclusion. The coupled elastic and electric fields both inside the inclusion and on the interface
of the inclusion and matrix are given.
The project supported by the National Natural Science Foundation of China 相似文献
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Dr. Liwei Dong Dr. Shijie Zhong Dr. Botao Yuan Dr. Yaqiang Li Dr. Jipeng Liu Dr. Yuanpeng Ji Dr. Dongjiang Chen Dr. Yuanpeng Liu Prof. Chunhui Yang Prof. Jiecai Han Prof. Weidong He 《Angewandte Chemie (International ed. in English)》2023,62(23):e202301073
Without excess Li, anode-free Li-metal batteries (AFLMBs) have been proposed as the most likely solution to realizing highly-safe and cost-effective Li-metal batteries. Nevertheless, short cyclic life puzzles conventional AFLMBs due to anodic dead Li accumulation with a local current concentration induced by irreversible electrolyte depletion, insufficient active Li reservoir and slow Li+ transfer at the solid electrolyte interphase (SEI). Herein, SrI2 is introduced into carbon paper (CP) current collector to effectively suppress dead Li through synergistic mechanisms including reversible I−/I3− redox reaction to reactivate dead Li, dielectric SEI surface with SrF2 and LiF to prevent electrolyte decomposition and highly ionic conductive (3.488 mS cm−1) inner layer of SEI with abundant LiI to enable efficient Li+ transfer inside. With the SrI2-modified current collector, the NCM532/CP cell delivers unprecedented cyclic performances with a capacity of 129.2 mAh g−1 after 200 cycles. 相似文献
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Jiecai Han Huaixin Guo Mingfu Zhang Ningning Song Chenghai Xu 《Crystal Research and Technology》2012,47(5):485-490
Nd3+‐doped Y3Al5O12 single crystals have been grown by the horizontal directional solidification (HDS) method in different thermal zone. The Grashof (Gr), Prandtl (Pr), Marangoni (Ma) and Rayleigh (Ra) numbers of melt in HDS system have been discussed for our experimental system to understand the mechanism of melt flow patterns and concentration gradient of dopant. The concentration gradient of Nd3+ ions was explained with melt flow processes during crystal growth in different thermal zone, and results indicated that high growth temperature will be helpful for uniformity of dopant in HDS‐grown single crystal. The main microscopic growth defects such as bubbles and irregular inclusions in HDS‐grown Nd:YAG crystals were observed, and the causes were discussed as well. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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This paper discusses electromagnetic boundary conditions on crack faces in magneto- electroelastic materials, where piezoelectric, piezomagnetic and magnetoelectric effects are coupled. A notch of finite thickness in these materials is also addressed. Four idealized electromagnetic boundary conditions assumed for the crack-faces are separately investigated, i.e. (a) electrically and magnetically impermeable (crack-face), (b) electrically impermeable and magnetically permeable, (c) electrically permeable and magnetically impermeable, and (d) electrically and magnetically permeable. The influence of the notch thickness on important parameters, such as the field intensity factors, the energy release rate at the notch tips and the electromagnetic fields inside the notch, are studied and the results are obtained in closed-form. Results under different idealized electromagnetic boundary conditions on the crack-face are compared, and the applicability of these idealized assumptions is discussed.The project supported by the National Natural Science Foundation of China (10102004) The English text was polished by Yunming Chen. 相似文献