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排序方式: 共有1134条查询结果,搜索用时 31 毫秒
171.
Cong Li Rui Zang Pengxin Li Zengming Man Shijian Wang Xuemei Li Yuhan Wu Shuaishuai Liu Prof. Guoxiu Wang 《化学:亚洲杂志》2018,13(3):342-349
Prussian blue and its analogues (PBAs) have been recognized as one of the most promising cathode materials for room‐temperature sodium‐ion batteries (SIBs). Herein, we report high crystalline and Na‐rich Prussian white Na2CoFe(CN)6 nanocubes synthesized by an optimized and facile co‐precipitation method. The influence of crystallinity and sodium content on the electrochemical properties was systematically investigated. The optimized Na2CoFe(CN)6 nanocubes exhibited an initial capacity of 151 mA h g?1, which is close to its theoretical capacity (170 mA h g?1). Meanwhile, the Na2CoFe(CN)6 cathode demonstrated an outstanding long‐term cycle performance, retaining 78 % of its initial capacity after 500 cycles. Furthermore, the Na2CoFe(CN)6 Prussian white nanocubes also achieved a superior rate capability (115 mA h g?1 at 400 mA g?1, 92 mA h g?1 at 800 mA g?1). The enhanced performances could be attributed to the robust crystal structure and rapid transport of Na ions through large channels in the open‐framework. Most noteworthy, the as‐prepared Na2CoFe(CN)6 nanocubes are not only low‐cost in raw materials but also contain a rich sodium content (1.87 Na ions per lattice unit cell), which will be favorable for full cell fabrication and large‐scale electric storage applications. 相似文献
172.
Let A be a 0 − 1 matrix with precisely two 1’s in each column and let 1 be the all-one vector. We show that the problems of deciding whether the linear system
(1) defines an integral polyhedron,
(2) is totally dual integral (TDI), and
(3) box-totally dual integral (box-TDI)
are all co-NP-complete, thereby confirming the conjecture on NP-hardness of recognizing TDI systems made by Edmonds and Giles
in 1984.
Supported in part by NSA grant H98230-05-1-0081 and NSF grants DMS-0556091 and ITR-0326387.
Supported in part by the Research Grants Council of Hong Kong and Seed Funding for Basic Research of HKU. 相似文献
173.
Alejandro Capap Ming-Dong Zhou Shu-Liang Zang Fritz E. Kühn 《Journal of organometallic chemistry》2008,693(20):3240-3244
Equimolar reactions of the derivatives of ((2-hydroxynapthalen-1-yl)methylene)aniline with methyltrioxorhenium (MTO) lead to complexes 1–4, where MTO is coordinated via the oxygen of the former hydroxyl-group to MTO. The resulting complexes are very stable but not particularly catalytically active if no electron acceptor resides on the Schiff base. The electron withdrawing groups placed on the Schiff base ligand have the effect of increasing the catalytic activity but somewhat decrease the complex stability. 相似文献
174.
Dr. Pengwei Li Linfang Yan Qingli Cao Prof. Chao Liang He Zhu Sihui Peng Yongpeng Yang Yuncai Liang Rudai Zhao Prof. Shuangquan Zang Prof. Yiqiang Zhang Prof. Yanlin Song 《Angewandte Chemie (International ed. in English)》2023,62(13):e202217910
Low-dimensional Ruddlesden-Popper (LDRP) perovskites still suffer from inferior carrier transport properties. Here, we demonstrate that efficient exciton dissociation and charge transfer can be achieved in LDRP perovskite by introducing γ-aminobutyric acid (GABA) as a spacer. The hydrogen bonding links adjacent spacing sheets in (GABA)2MA3Pb4I13 (MA=CH3NH3+), leading to the charges localized in the van der Waals gap, thereby constructing “charged-bridge” for charge transfer through the spacing region. Additionally, the polarized GABA weakens dielectric confinement, decreasing the (GABA)2MA3Pb4I13 exciton binding energy as low as ≈73 meV. Benefiting from these merits, the resultant GABA-based solar cell yields a champion power conversion efficiency (PCE) of 18.73 % with enhanced carrier transport properties. Furthermore, the unencapsulated device maintains 92.8 % of its initial PCE under continuous illumination after 1000 h and only lost 3 % of its initial PCE under 65 °C for 500 h. 相似文献
175.
Yan Jin Qiu-Chen Peng Jing-Wen Xie Prof. Dr. Kai Li Prof. Dr. Shuang-Quan Zang 《Angewandte Chemie (International ed. in English)》2023,62(19):e202301000
In this study, a pair of chiral copper(I) cluster-assembled materials (R/S- 2 ) was prepared, exhibiting unique photo-response characteristics with a concentration-wavelength correlation property in DMSO solution. By the combination of R/S- 2 with a polymethyl methacrylate (PMMA) matrix, the first photo-activated circularly polarized luminescence (CPL) film was developed, the CPL signal (glum=9×10−3) of which could be induced by UV light irradiation. Moreover, the film exhibited a reversible photo-response and extremely good fatigue resistance. Mechanism study revealed that the photo-response properties of the R/S- 2 solution and film are attributed to the aggregation-induced emission (AIE) characteristics of R/S- 2 and a photo-induced deoxygenation process. This study enriches the types of luminescent cluster-assembled molecules and provides a new strategy for the construction of metal cluster-based stimuli-responsive composite materials. 相似文献
176.
Qiu-Chen Peng Dr. Yu-Bing Si Jia-Wang Yuan Qi Yang Zi-Ying Gao Dr. Yuan-Yuan Liu Dr. Zhao-Yang Wang Dr. Kai Li Prof. Shuang-Quan Zang Prof. Ben Zhong Tang 《Angewandte Chemie (International ed. in English)》2023,62(40):e202308194
X-ray imaging technology has achieved important applications in many fields and has attracted extensive attentions. Dynamic X-ray flexible imaging for the real-time observation of the internal structure of complex materials is the most challenging type of X-ray imaging technology, which requires high-performance X-ray scintillators with high X-ray excited luminescence (XEL) efficiency as well as excellent processibility and stability. Here, a macrocyclic bridging ligand with aggregation-induced emission (AIE) feature was introduced for constructing a copper iodide cluster-based metal–organic framework (MOF) scintillator. This strategy endows the scintillator with high XEL efficiency and excellent chemical stability. Moreover, a regular rod-like microcrystal was prepared through the addition of polyvinyl pyrrolidone during the in situ synthesis process, which further enhanced the XEL and processibility of the scintillator. The microcrystal was used for the preparation of a scintillator screen with excellent flexibility and stability, which can be used for high-performance X-ray imaging in extremely humid environments. Furthermore, dynamic X-ray flexible imaging was realized for the first time. The internal structure of flexible objects was observed in real time with an ultrahigh resolution of 20 LP mm−1. 相似文献
177.
178.
Dr. Peng Luo Dr. Xue-Jing Zhai Dr. Sha Bai Dr. Yu-Bing Si Dr. Xi-Yan Dong Prof. Dr. Ying-Feng Han Prof. Dr. Shuang-Quan Zang 《Angewandte Chemie (International ed. in English)》2023,62(22):e202219017
Chiral Au nanoclusters have promising application prospects in chiral sensing, asymmetric catalysis, and chiroptics. However, enantiopure superatomic homogold clusters with crystallographic structures emitting bright circularly polarized luminescence (CPL) remain challenging. In this study, we designed chiral N-heterocyclic carbenes (NHCs), and for the first time enantioselectively synthesized a pair of monovalent cationic superatomic Au13 clusters. This new enantiomeric pair of clusters has a quasi-C2 symmetric core and exhibited CPL with an unprecedent solution-state quantum yield (QY) of 61 % among those of the atomically precise Au nanoclusters. DFT calculations provided insights into the circular dichroism behavior, and revealed the origin of CPL from superatomic Au clusters. This work opens a new avenue for developing novel homochiral nanoclusters using chiral NHC ligands and provides fundamental understanding of the origin of the chiroptics of metal clusters. 相似文献
179.
Qingbin Li Yihan Zhang Junfeng Lin Ye Zou Pu Wang Dr. Zhengsheng Qin Yongshuai Wang Dr. Yang Li Prof. Dr. Yu Zhang Dr. Can Gao Prof. Dr. Yaping Zang Prof. Dr. Wenping Hu Prof. Dr. Huanli Dong 《Angewandte Chemie (International ed. in English)》2023,62(42):e202308146
The development of blue-emissive ambipolar organic semiconductor is an arduous target due to the large energy gap, but is an indispensable part for electroluminescent device, especially for the transformative display technology of simple-structured organic light-emitting transistor (SS-OLET). Herein, we designed and synthesized two new dibenzothiophene sulfone-based high mobility blue-emissive organic semiconductors (DNaDBSOs), which demonstrate superior optical property with solid-state photoluminescent quantum yield of 46–67 % and typical ambipolar-transporting properties in SS-OLETs with symmetric gold electrodes. Comprehensive experimental and theoretical characterizations reveal the natural of ambipolar property for such blue-emissive DNaDBSOs-based materials is ascribed to a synergistic effect on lowering LUMO level and reduced electron injection barrier induced by the interfacial dipoles effect on gold electrodes due to the incorporation of appropriate DBSO unit. Finally, efficient electroluminescence properties with high-quality blue emission (CIE (0.179, 0.119)) and a narrow full-width at half-maximum of 48 nm are achieved for DNaDBSO-based SS-OLET, showing good spatial control of the recombination zone in conducting channel. This work provides a new avenue for designing ambipolar emissive organic semiconductors by incorporating the synergistic effect of energy level regulation and molecular-metal interaction, which would advance the development of superior optoelectronic materials and their high-density integrated optoelectronic devices and circuits. 相似文献
180.
Dr. Junning Kou Dr. Qi Wu Dr. Dongxu Cui Dr. Yun Geng Dr. Kunhao Zhang Prof. Dr. Min Zhang Prof. Dr. Hongying Zang Prof. Dr. Xinlong Wang Prof. Dr. Zhongmin Su Prof. Dr. Chunyi Sun 《Angewandte Chemie (International ed. in English)》2023,62(47):e202312733
Chiral induction has been an important topic in chemistry, not only for its relevance in understanding the mysterious phenomenon of spontaneous symmetry breaking in nature but also due to its critical implications in medicine and the chiral industry. The induced chirality of fullerenes by host–guest interactions has been rarely reported, mainly attributed to their chiral resistance from high symmetry and challenges in their accessibility. Herein, we report two new pairs of chiral porous aromatic cages (PAC), R- PAC-2 , S- PAC-2 (with Br substituents) and R- PAC-3 , S- PAC-3 (with CH3 substituents) enantiomers. PAC-2 , rather than PAC-3 , achieves fullerene encapsulation and selective binding of C70 over C60 in fullerene carbon soot. More significantly, the occurrence of chiral induction between R- PAC-2 , S- PAC-2 and fullerenes is confirmed by single-crystal X-ray diffraction and the intense CD signal within the absorption region of fullerenes. DFT calculations reveal the contribution of electrostatic effects originating from face-to-face arene-fullerene interactions dominate C70 selectivity and elucidate the substituent effect on fullerene encapsulation. The disturbance from the differential interactions between fullerene and surrounding chiral cages on the intrinsic highly symmetric electronic structure of fullerene could be the primary reason accounting for the induced chirality of fullerene. 相似文献