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排序方式: 共有1913条查询结果,搜索用时 55 毫秒
1.
Annals of Global Analysis and Geometry - We study harmonic maps from a 3-manifold with boundary to $$\mathbb {S}^1$$ and prove a special case of Gromov dihedral rigidity of three-dimensional cubes... 相似文献
2.
Designs, Codes and Cryptography - It has been shown that all the known binary Golay complementary sequences of length $$2^m$$ can be obtained by a single binary Golay complementary array of... 相似文献
3.
Shilin Jiang Dr. Yalan Liu Dr. Lin Wang Prof. Zhifang Chai Prof. Wei-Qun Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(60):e202201145
The coordination chemistry of f-block elements (lanthanide and actinide) in molten salts has become a resounding topic in view of its great importance to the research and development (R&D) of molten salt reactors and pyroprocessing. In this Review article, a general overview of the coordination chemistry of f-block elements in molten salts is provided including past achievements and recent advances. Particular emphases are placed on the oxidation state, speciation, and solution structure of f-block metal ions in molten salts, as well as their relationships with the salt composition. Furthermore, this review briefly discusses the spectroscopic and theoretical methods that complement each other in revealing the coordination properties. 相似文献
4.
5.
Ling-Ying Xia Dr. Ying-Ning Zheng Prof. Wen-Bin Liang Dr. Meng-Jie Li Tao Hu Prof. Ruo Yuan Prof. Ya-Qin Chai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4087-4092
A new cosensitization photoelectrochemical (PEC) strategy was established by using a donor–acceptor-type photoactive material, poly{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl} (PTB7-Th), as a signal indicator, which was cosensitized with bis(4,4′dicarboxyl-2,2′-bipyridyl)(4,5,9,14-tetraazabenzo[b]triphenylene)ruthenium(II) ([Ru(dcbpy)2dppz]2+) embedded in the grooves of the DNA duplex and fullerene (nano-C60) immobilized on the surface of DNA nanoflowers for microRNA assay. [Ru(dcbpy)2dppz]2+ and nano-C60 could effectively enhance the photoelectric conversion efficiency (PCE) of PTB7-Th as a result of well-matched energy levels among nano-C60, [Ru(dcbpy)2dppz]2+ and PTB7-Th, leading to a clearly enhanced photocurrent signal. Meanwhile, a target recycling magnification technique based on duplex-specific nuclease was applied in this work to obtain higher detection sensitivity. The proposed biosensor demonstrated excellent analytical properties within a linear detection range of 2.5 fm to 2.5 nm and a limit of detection down to 0.83 fm . Impressively, this cosensitization PEC strategy offers an effective and convenient avenue to significantly improve the PCE of a photoactive material, resulting in a remarkably improved photocurrent signal for ultrasensitive and highly accurate detection of various targets. 相似文献
6.
In this paper, we study one-dimensional linear degenerate wave equations with a distributed controller. We establish observability inequalities for degenerate wave equation by multiplier method. We also deduce the exact controllability for degenerate wave equation by Hilbert uniqueness method when the control acts on the nondegenerate boundary. Moreover, an explicit expression for the controllability time is given. 相似文献
7.
Peng Yang Xin Peng Ze-zhou Yang Prof. Ya-qin Chai Prof. Ruo Yuan Prof. Wen-bin Liang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(40):8767-8773
The evident contradiction between high local-concentration-based substrate reactivity and free-diffusion-based high reaction efficiency remains one of the important challenges in chemistry. Herein, we propose an efficient aggregation-induced synergism through the hydrophobic-driven self-assembly of amphiphilic oligonucleotides to generate high local concentration whereas retaining high reaction efficiency through hydrophobic-based aggregation, which is important for constructing efficient DNA nanomachines for ultrasensitive applications. MicroRNA-155, used as a model, triggered strand displacement amplification of the DNA monomers on the periphery of the 3D DNA nanomachine and generated an amplified fluorescent response for its sensitive assay. The local concentration of substrates was increased by a factor of at least 9.0×105 through hydrophobic-interaction-based self-assembly in comparison with the traditional homogeneous reaction system, achieving high local-concentration-based reactivity and free-diffusion-based enhanced reaction efficiency. As expected, the aggregation-induced synergism by hydrophobic-driven self-assembly of amphiphilic oligonucleotides created excellent properties to generate a 3D DNA nanomachine with potential as an assay for microRNA-155 in cells. Most importantly, this approach can be easily expanded for the bioassay of various biomarkers, such as nucleotides, proteins, and cells, offering a new avenue for simple and efficient applications in bioanalysis and clinical diagnosis. 相似文献
8.
Dan-Dan Wang Li Song You-Yu Wang Jia-Yu Guo Hang-Yan Shen Xiao-Rong Wang Wen-Xiang Chai 《应用有机金属化学》2020,34(4):e5561
Four new heteroleptic [Cu(NN)P2]+-type cuprous complexes— 1 -TPP, 2 -POP, 3 -Xantphos, and 4 -DPPF—were designed and synthesized using a diimine ligand 2-(2′-pyridyl)benzoxazole (2-PBO) and different phosphine ligands (TPP, triphenylphosphine; POP, bis[2-(diphenylphosphino)phenyl]ether; Xantphos, 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene; DPPF, 1,1′-bis(diphenylphosphino)-ferrocene). All complexes were characterized using single-crystal X-ray diffraction, spectroscopic analysis (infrared, UV–Vis.), elemental analysis, and photoluminescence (PL). Single-crystal X-ray diffraction revealed complexes 1 – 4 as isolated cation complex structures with a tetrahedral CuN2P2 coordination geometry and diverse P–Cu–P angles. Their UV–Vis. absorption spectra exhibited a blue-shift sequence in wavelength with an enlarged P–Cu–P angle from 4 to 2 then to 3 and then to 1 . The PL emission peaks of 1 – 3 also exhibited a similar blue-shift sequence ( 2 → 3 → 1 ). Their PL lifetime in microseconds (~7.5, 5.1, and 4.7 μs for 1 , 2 , and 3 , respectively) indicated that their PL behavior represents phosphorescence. Time-dependent density functional theory (TD-DFT) calculation and wavefunction analysis revealed that S1 and T1 states of 1 – 3 should be assigned as metal–ligand and ligand–ligand charge-transfer (ML + L'L)CT states. Their UV–Vis. absorption and phosphorescence should be attributed to the charge transfer from the P–Cu–P segment to the 2-PBO ligand. Therefore, as the P–Cu–P angle increased (lower HOMO), the energy of S1 and T1 states also increased, following the change of PL color. 相似文献
9.
Sustainable synthesis of quinolines (pyridines) catalyzed by a cheap metal Mn(I)-NN complex catalyst
This study represents the first example of a bidentate phosphine-free manganese(I)-NN complex catalyst for the synthesis of quinolines (pyridines) through acceptorless dehydrogenative condensation of various secondary alcohols with amino alcohols. The coupling reactions occurred at 3 mol% catalyst loading and 110°C, and tolerated diverse functional groups. Moderate to excellent yields ranging from 45% to 89% were achieved after 12 hr of reaction. The present protocol provides a concise and environmentally friendly method for the construction of heterocyclic compounds. 相似文献
10.
Nonlinear Dynamics - This paper focuses on the design and implementation of optimization-based predictive control for the problem of missile interception. Due to the inherent nonlinearities of the... 相似文献