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521.
金属锂具有高理论比容量和低氧化还原电位, 被认为是高能量密度二次电池最理想的负极材料之一, 但其在循环过程中的枝晶生长和体积变化易造成电池失效和安全隐患. 以孔径为5 μm左右的自制三维多孔铜为基底, 在其表面电沉积锌层(3D Cu@Zn), 作为金属锂沉积的集流体, 构筑无枝晶锂金属电极. 三维多孔铜的孔结构稳定, 孔径大小适宜, 可有效降低局部电流密度和缓解体积变化. 锌镀层可降低锂金属的形核过电位, 诱导锂的均匀沉积, 有效抑制锂枝晶生长. 以3D Cu@Zn为集流体, 锂沉积面积容量为4 mAh•cm–2, 电极表面仍无枝晶出现, 经过锂剥离后表面仍然光滑; 而铜箔上沉积的锂显示明显的枝晶和不均匀性, 3D Cu上沉积的锂显示局部不均匀性和一定量枝晶. 在电流密度为0.5和 1 mA•cm–2, 面积容量为1 mAh•cm–2条件下, Li||3D Cu@Zn半电池获得了稳定的库伦效率; 在2 mA•cm–2的高电流密度和1 mAh•cm–2的面积容量条件下, Li||3D Cu@Zn@Li对称电池可稳定循环700 h以上; 以3D Cu@Zn@Li为负极, LiFePO4为正极的全电池, 在1 C倍率下, 经过150次循环后仍保持88 mAh•g–1的容量, 均明显优于Cu片和3D Cu作为集流体的锂金属电极. 相似文献
522.
Weipeng Chen Guojun Zhou Zhuolun Gou Sen Wang Yuanqi Zhai Tian Han Jürgen Schnack Yanzhen Zheng 《中国化学快报》2021,32(2):838-841
A new family of isostructural 3 d-4 f polymetallic complexes,formulated as [Cu_6Ln_5(μ_3OH)_9(C_4H_8O_2N)_6(C_5H_4ON)_6(H_2O)_9]·(ClO_4)_6·(H_2O)_(22)(Ln=Pr,1;Nd,2;Sm,3;Eu,4;Gd,5),was successfully isolated through the simple hydrolysis reaction of 2-aminoisobutyric acid,2-hydroxypyridine,Cu(CH_3COO)_2·H_2O,and Ln(ClO_4)_3·6 H_2O.Notably,the [Cu_6Ln_5] clusters with high molecular symmetry ofD_(3 h) are rare examples of2-aminoisobutyric acid-based 3 d-4 f clusters.The successful theoretical modeling of 5 yielded that the Gd-Gd exchange is of order 0.2 K,whereas the Gd-Cu exchange is an order of magnitude larger.Magnetization data collected for comp lex 5 yield a magnetic entropy change(-ΔSm) of 19.6 J kg ~1 K~11 at 3 K and 7 T,which may be attributed to the weak magnetic interactions between the component metal ions. 相似文献
523.
Zhixiang Wu Tao Xie Yafei Luo Wei Zhuo Jinke Gu Xiao Yan Xin Sun Ke Zuo Xingyu Liu Ya Gan Li Liang Gang He Wei Liu Xiaojun Gou Dianyong Tang Hubing Shi Jianping Hu 《应用有机金属化学》2019,33(7)
Density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT) both were used to explore the impacts of different inductive substituents on the photophysical properties, radiative/nonradiative processes and photodeactivation mechanism for the Pt (II) complex with novel spiro‐arranged tetradentate ligand. Spectrum simulations show that the electron donor methoxyl (‐OCH3) group can cause the emission wavelength to red‐shift but have little effect on the absorption spectrum. In the simulation of the radiative decay process for the tetradentate Pt (II) complex, the singlet‐triplet splitting energy is reduced by the introduction of substituents with strong electron‐releasing capability (i.e., from the original trifluoromethyl (‐CF3) group to ‐OCH3 group), accompanied with a lower radiative rate constant (kr). The analyses of non‐radiative decay processes show that the substitution of ‐OCH3 group on azole rings reduces the energy barriers of thermally activated non‐radiative photodeactivation pathway, which in turn increases the temperature‐dependent non‐radiative rate constants (knr(T)). In addition, the substitution of ‐CF3 by ‐OCH3 group slightly weakens molecular rigidity and enhances the Huang‐Rhys factor, but decreases the SOC between the triplex excited (T) state and the ground (S0) state. Thereby, the two complexes may have the similar temperature‐independent non‐radiative rate constant (knr’). This work offers theoretical guidance for the design and optimization of the efficient organic light emitting diode (OLED) materials based on the structure of tetradentate Pt (II) complexes. 相似文献
524.
Wuyang Hua Dr. Gang Xu Dr. Jian Zhao Dr. Z. Wang Jiapeng Lu Prof. Wenfang Sun Prof. Shaohua Gou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(72):17495-17503
Subtle ligand modifications on RuII-polypyridyl complexes may result in different excited-state characteristics, which provides the opportunity to tune their photo-physicochemical properties and subsequently change their biological functions. Here, a DNA-targeting RuII-polypyridyl complex (named Ru1 ) with highly photosensitizing 3IL (intraligand) excited state was designed based on a classical DNA-intercalator [Ru(bpy)2(dppz)] ⋅ 2 PF6 by incorporation of the dppz (dipyrido[3,2-a:2′,3′-c]phenazine) ligand tethered with a pyrenyl group, which has four orders of magnitude higher potency than the model complex [Ru(bpy)2(dppz)] ⋅ 2 PF6 upon light irradiation. This study provides a facile strategy for the design of organelle-targeting RuII-polypyridyl complexes with dramatically improved photobiological activity. 相似文献
525.
Li Zheng-Fa Zhu Ling-Yun Chen Shi-Qian Chen Zai-Gang Gou Xiang-Feng 《Nonlinear dynamics》2022,109(3):1297-1324
Nonlinear Dynamics - Multi-state meshing characteristics induced by backlash and contact ratio in the gear pair are an unsolved puzzle about its relationship to safety characteristics of the gear... 相似文献
526.
Development of temporal and spatial high‐order schemes for two‐fluid seven‐equation two‐pressure model and its applications in two‐phase flow benchmark problems
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Current existing main nuclear thermal‐hydraulics (T‐H) system analysis codes, such as RALAP5, TRACE, and CATHARE, play a crucial role in the nuclear engineering field for the design and safety analysis of nuclear reactor systems. However, two‐fluid model used in these T‐H system analysis codes is ill posed, easily leading to numerical oscillations, and the classical first‐order methods for temporal and special discretization are widely employed for numerical simulations, yielding excessive numerical diffusion. Two‐fluid seven‐equation two‐pressure model is of particular interest due to the inherent well‐posed advantage. Moreover, high‐order accuracy schemes have also attracted great attention to overcome the challenge of serious numerical diffusion induced by low‐order time and space schemes for accurately simulating nuclear T‐H problems. In this paper, the semi‐implicit solution algorithm with high‐order accuracy in space and time is developed for this well‐posed two‐fluid model and the robustness and accuracy are verified and assessed against several important two‐phase flow benchmark tests in the nuclear engineering T‐H field, which include two linear advection problems, the oscillation problem of the liquid column, the Ransom water faucet problem, the reversed water faucet problem, and the two‐phase shock tube problem. The following conclusions are achieved. (1) The proposed semi‐implicit solution algorithm is robust in solving two‐phase flows, even for fast transients and discontinuous solutions. (2) High‐order schemes in both time and space could prevent excessive numerical diffusion effectively and the numerical simulation results are more accurate than those of first‐order time and space schemes, which demonstrates the advantage of using high‐order schemes. 相似文献
527.
Polymer‐derived methods are one of the most important tools for the synthesis of ceramics with a finely dispersed microstructure. In this study, a soluble and meltable ZrC/C pre‐ceramic polymer, P‐DACZ, (which would later exhibit a high ceramic yield of 71 wt%) was synthesized via radical polymerization. By adding low molecular weight polycarbosilane in any proportion during the radical polymerization process of P‐DACZ, a soluble and meltable ZrC/SiC/C pre‐ceramic precursor, PCS‐DACZ (which would later exhibit a high ceramic yield of >80 wt%) was synthesized. After annealing at 1400 °C under an argon flow, the precursors converted into bulk ZrC/C and ZrC/SiC/C ceramic nanocomposites. The ZrC nanoparticles could resist any grain growth when heat‐treated at temperatures above 1800 °C because the C or SiC matrix prevented long‐range atomic diffusion of zirconium. Such ceramic nanocomposites would be suitable for structural and (multi)functional applications at harsh environments with high temperatures. 相似文献
528.
Hong Shen Lin Cheng Huaze Dong Haibin Zhu Shaohua Gou Xuetai Chen 《Solid State Sciences》2010,12(3):367-372
Interactions of dithioether ligands L2, L4 and L5 (L2 = 1,3-bis(4-(3-pyridyl) pyrimidin-2-ylthio) propane; L4 = 1,3-bis[4-(3-pyridyl) pyrimidinyl thiomethyl]benzene; L5 = 1,4-bis[4-(3-pyridyl)pyrimidinylthiomethyl] benzene) with Mn(II) ions and NH4SCN in an analogous way led to the formation of two discrete mononuclear complexes and a one-dimensional chain, respectively, which may be attributed to the different flexibility and positional isomerism of the ligands. 相似文献
529.
Auttasit Tubtimtae Kun-Lun Wu Hao-Yu Tung Ming-Way Lee Gou Jen Wang 《Electrochemistry communications》2010,12(9):1158-1160
We present a new photosensitizer – Ag2S quantum dots (QDs) – for solar cells. The QDs were grown by the successive ionic layer adsorption and reaction deposition method. The assembled Ag2S-QD solar cells yield a best power conversion efficiency of 1.70% and a short-circuit current of 1.54 mA/cm2 under 10.8% sun. The solar cells have a maximal external quantum efficiency (EQE) of 50% at λ = 530 nm and an average EQE of ~ 42% over the spectral range of 400–1000 nm. The effective photovoltaic range covers the visible and near-infrared spectral regions and is ~ 2–4 times broader than that of the cadmium chalcogenide systems — CdS and CdSe. The results show that Ag2S QDs can be used as a highly efficient and broadband sensitizer for solar cells. 相似文献
530.
Xiao Chi Ma Zhan Ping Gou Chang Yuan Wang Ji Hong Yao Xiu Lan Xin Yuan Lin Ke Xin Liu 《中国化学快报》2010,21(5):587-589
<正>A new ent-labdane diterpenoid lactone was isolated from Andrographis paniculata.Its structure was identified on the basis of spectral data including 2D NMR. 相似文献