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101.
Ning Yu Siwen Tao Jiawen Cui Huawei Zhou Yan Chen Shuting Cui Xiaorui Gao Jie Yin Xuejing Liu Xianxi Zhang 《应用有机金属化学》2020,34(12):e5982
At present, developing new organic–inorganic hybrid materials (OIHM) and studying their photoelectric properties is an important research field. In this work, the OIHM (CH3NH3)2HgCl4 (MA2HgCl4) single crystal and thin film are prepared. The results show that the crystal structure of MA2HgCl4 has a monoclinic crystal system with P21/c (14) space group (unit cell dimensions 7.776 × 12.917 × 10.993 Å, 90.00 × 96.366 × 90.00) by solving the single crystal diffraction data. The band gap of MA2HgCl4 is calculated to be approximately 3.21 eV. To the best of our knowledge, this is the first study on MA2HgCl4 for optoelectronic application. The photodetector based on MA2HgCl4 thin film is highly selective for ultraviolet (UV) light (369 nm), and has a poor response for visible light. The electrochemical impedance spectrum shows that the impedance value (2 kΩ) of the device under 369 nm UV light is four magnitudes lower than that (107 Ω) under dark. Thus, MA2HgCl4 has the nature of a photoconductor. The density functional theory indicates that the valence band maximum (VBM) of MA2HgCl4 is mainly derived from Cl-3p state, Hg-5d state and organic CH3NH3+ state also participate in the formation of the VBM band. The electron states of VBM and the conduction band minimum of MA2HgCl4 come from inorganic HgCl42− clusters. 相似文献
102.
Sulfur/multi-walled carbon nanotubes (MWCNTs) composites have been successfully prepared by an in situ growth strategy as a cathode material for lithium/sulfur battery. The microstructure and morphology of the sulfur/MWCNTs composites are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). From the results, it is found that the nano-sulfur (shell) grows around the MWCNTs (core) and is well-dispersed over the whole surface of the MWCNTs. Tested by coin type cells, the composite materials exhibited the sulfur utilization approaching to 78% for the first cycle, the capacity retention closing to 84% after 100 cycles at various rates. The excellent electrochemical performance could be attributed to the nano-size sulfur and the homogeneous distribution of sulfur on MWCNTs matrix, resulting from this novel in situ growth method, which not only enhances the reactive activity of sulfur during charge–discharge processes but also provides stable electrical and ionic transfer channels. 相似文献
103.
104.
Shuting Cai Kaori Nagatou Yoshitaka Watanabe 《Numerical Functional Analysis & Optimization》2013,34(10):1195-1220
We propose a numerical method to enclose a solution of the FitzHugh-Nagumo equation with Neumann boundary conditions. We construct, on a computer, a set which satisfies the hypothesis of Schauder's fixed point theorem for a compact map in a certain Sobolev space, which, therefore contains a solution. Several verified results are presented. 相似文献
105.
106.
The differential quadrature method (DQM) has been studied for years and it has been shown by many researchers that the DQM is an attractive numerical method with high efficiency and accuracy. The conventional DQM is mostly effective for one‐dimensional and multidimensional problems with geometrically regular domains. But to deal with problems on a triangular domain, we will meet difficulties. In this article we will study how to solve problems on a triangular domain by using DQM combined with the domain decomposition method (DDM). © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005 相似文献
107.
Monolithic columns have been prepared with a novel bonded silica stationary phase, tetradecylamine bonded silica (TDAS), and used in pressurized capillary electrochromatography (pCEC). The monolithic silica column matrix was prepared by a sol-gel process and then chemically modified with the spacer (3-glycidoxypropyl)trimethoxysilane and tetradecylamine. The introduced embedded polar amine groups dominated the charge on the surface of the monolithic stationary phase and generated an EOF from cathode to anode under acidic conditions. The tetradecyl hydrophobic chains in TDAS provide chromatographic interactions. The chromatographic characteristics of the prepared monolithic column were studied. Some aromatic compounds including alkylbenzenes, aromatic hydrocarbons, phenols, and anilines were successfully separated on the TDAS monolithic column in pCEC mode. As expected, the TDAS monolithic stationary phases exhibit typical reversed-phase electrochromatographic behavior toward neutral solutes due to the introduced tetradecyl groups. Hydrophobic as well as electrophoretic migration processes within the monoliths were observed in the separation of basic anilines. Symmetrical peaks can be obtained for anilines because the embedded polar amine groups on the surface can effectively shield the adsorption of positively charged analytes onto the stationary phase. 相似文献
108.
Molecular dynamics simulations combined with spectroscopic analysis were applied to understand the nature of recognition in
molecularly imprinted polymers (MIPs), and for optimizing the MIP formulation. The best monomers for synthesizing imprinted
materials for 17β-estradiol (BE2) were selected by evaluating the strength of the template–monomer interaction derived from molecular dynamics
simulations. A number of potential functional monomers for BE2 were screened for hydrogen-bonding strength in order to analyze
template–monomer interactions favorable for synthesizing noncovalent MIPs, with the simulations revealing that methacrylic
acid, 2-(diethylamino)ethyl methacrylate, and methacrylamide provided the highest binding affinity to BE2. These theoretical
predictions agree with previously reported results on batch rebinding studies using the corresponding functional monomers
for synthesizing a series of MIPs. Molecular analysis such as 1H NMR was used for experimentally confirming the prevalent template–monomer interactions derived from the modeling results.
Molecular dynamics simulations indicating monomer dimerization in the prepolymerization solution correlated with the nature
of the porogenic solvent, which was confirmed by NMR studies on hydrogen-bonding interactions of methacrylic acid in different
solvents. Furthermore, batch rebinding studies revealed that the specific functionalities of the monomers essential to rebinding
are retained after polymerization, which proves that the application of computational methods for modeling the prepolymerization
solution provides useful information for optimizing real MIP systems. 相似文献
109.
压电现象在新能源开发、 传感、 医药材料设计及可穿戴电子设备中具有广泛的潜在应用, 并受到普遍重视. 在压电材料中, 聚偏氟乙烯(PVDF)及其共聚物因具有良好的柔韧性、 易加工性、 稳定性和生物相容性等优点而备受关注. 本文综合评述了近年来在制备工艺和材料复合两个维度提高PVDF基压电材料输出性能的研究进展. 在研究PVDF压电性原理的基础上, 阐释了流延法、 静电纺丝法、 拉丝法及纳米限域策略等工艺和添加小分子、 高分子、 石墨类粒子及无机纳米粒子等复合策略提升其压电性能的机理. 这些制备工艺的提高和填料的掺杂有助于偶极子的排列和高β相的形成. 最后, 对目前存在的一些挑战进行了概述和讨论, 并对PVDF基材料的发展前景提出展望. 相似文献