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71.
Herng TS Qi DC Berlijn T Yi JB Yang KS Dai Y Feng YP Santoso I Sánchez-Hanke C Gao XY Wee AT Ku W Ding J Rusydi A 《Physical review letters》2010,105(20):207201
We report direct evidence of room-temperature ferromagnetic ordering in O-deficient ZnO:Cu films by using soft x-ray magnetic circular dichroism and x-ray absorption. Our measurements have revealed unambiguously two distinct features of Cu atoms associated with (i) magnetically ordered Cu ions present only in the oxygen-deficient samples and (ii) magnetically disordered regular Cu2+ ions present in all the samples. We find that a sufficient amount of both oxygen vacancies (V(O)) and Cu impurities is essential to the observed ferromagnetism, and a non-negligible portion of Cu impurities is uninvolved in the magnetic order. Based on first-principles calculations, we propose a microscopic "indirect double-exchange" model, in which alignments of localized large moments of Cu in the vicinity of the V(O) are mediated by the large-sized vacancy orbitals. 相似文献
72.
We develop a new one-to-one correspondence between a two-dimensional (m × n, k, ρ) optical orthogonal code (2-D (m × n, k, ρ)-OOC) with AM-OPPTS (at most one-pulse per time slot) property and a certain combinatorial subject, called an n-cyclic holey packing of type m n . By this link, an upper bound on the size of a 2-D (m × n, k, ρ)-OOC with AM-OPPTS property is derived. Afterwards, we employ combinatorial methods to construct infinitely many 2-D (m × n, k, 1)-OOCs with AM-OPPTS property, whose existence was previously unknown. All these constructions meet the upper bounds with equality and are thus optimal. 相似文献
73.
Biao Ma Peng Wu Xing Wang Zhengyu Wang Hai‐Xia Lin Hui‐Xiong Dai 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(38):13469-13473
A rhodium(III)‐catalyzed domino annulation of simple olefins with diazo oxindoles to give spirooxindole pyrrolone products is described. This reaction can be formally viewed as the result of an anomalous tandem C?H activation, carbene insertion, Lossen rearrangement, and a nucleophilic addition process. The potential utility of this reaction was further demonstrated by the late‐stage diversification of drug molecules. 相似文献
74.
75.
Dongdong Li Luyao Wang Ernesto Yagüe Linlin Dai Xiumei Zhao Zibo Yang Shuang Zhi Yunhui Hu 《应用有机金属化学》2019,33(10)
An innovative ternary copper(II) complex, [Cu(Cl‐PIP)(Tyr)Cl]n, has been synthesized and characterized using infrared spectroscopy, elemental analysis and single‐crystal X‐ray diffraction analysis. X‐ray crystallography indicates that the Cu atom is five‐coordinated in a square‐pyramidal configuration. The unit forms a one‐dimensional chain along the crystallographic c‐axis. The complex was screened for cytotoxicity against a panel of eight human cancer cell lines, namely MDA‐MB‐231, CAL‐51, K562, HeLa, SGC‐7901, A549, MCF‐7 and SMMC‐7721. The best anticancer activity was obtained with triple‐negative breast cancer CAL‐51 and MDA‐MB‐231 cell lines, with IC50 values in the range 0.035–0.10 μM, and this was better than using carboplatin. The complex inhibits proteasomal chymotrypsin‐like activity, and docking studies reveal its interaction with 20S proteasome. In addition, the complex causes accumulation of ubiquitinated proteins, induces apoptosis and inhibits cell proliferation, indicating its great potential as a novel therapy for triple‐negative breast cancer. 相似文献
76.
77.
Qing Dai Nongyue He Kuiping Weng Baoping Lin Zuhong Lu Chunwei Yuan 《Journal of inclusion phenomena and macrocyclic chemistry》1999,35(1-2):11-21
The photocatalytic activities of titanium dioxide (TiO2) supported on hexagonal mesoporous silica (HMS), zeolite Y (NaY) were investigated by using the photodegradation of 2,4,6-trichlorophenol (TCP) as test reactions. It was found that the photocatalytic activity of TiO2 on HMS was much higher than that of TiO2 powders, and that of TiO2 on NaY. It was also found that TiO2/HMS had maximal photocatalytic activity at a lower Ti content. The larger the pore size of HMS used as the support of TiO2, the better the photocatalytic activity of TiO2 for degradating of organic pollutant. These observations suggested that the supported structure was a main factor responsible for enhancement of the photocatalytic activity of TiO2. Characterization of the samples by TEM, XRD, BET, and UV-vis diffuse reflectance spectra indicated that the structures of HMS and TiO2 were confirmed and TiO2 did not enter into the HMS framework and was formed as nanoparticles on all supports. 相似文献
78.
Lin-Feng Dai Qian Liang Tie Liu Ming-Yu He Ping Zhao 《Natural product research》2016,30(14):1639-1645
One new tigliane-type diterpene, 4-deoxy-4(β)H-8-hydroperoxyphorbol-12-benzoate-13-isobutyrate (1), together with two known diterpenoids, 3-acetyl-5,8-dibenzoyl-14α-propanoyl-13,17-epoxy-7-myrsinaone diterpene with C9–C10 cyclised to form an additional lactone ring (2), Euphodendriane A (3) have been isolated from the whole plants of Euphorbia dracunculoides Lam. Their structures were elucidated by means of extensive spectroscopic analysis (NMR and HR-ESI-MS) and comparison with data reported in the literature. This is the first isolation of 8-hydroperoxy tigliane diterpene (1) from the genus of Euphorbia. All compounds were evaluated for their antifungal activities. 相似文献
79.
Several aryl halides have been coupled using the zero valent nickel catalyst [(PPh3)nNi(0)], to give the biaryl in moderate to good yield, employing the ionic liquid [bmim]PF6. The ionic liquid and catalyst were recycled after extraction of the biaryl. 相似文献
80.
On the basis of the reactions of camphor-derived sulfur ylide with alpha-ylidene-beta-diketones, highly efficient and selective synthesis of optically active dihydrofurans has been achieved. 相似文献