排序方式: 共有49条查询结果,搜索用时 31 毫秒
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Li X Ko YJ Wang H Bowen KH Guevara-García A Martínez A 《The Journal of chemical physics》2011,134(5):054318
The copper-nucleoside anions, Cu(-)(cytidine) and Cu(-)(uridine), have been generated in the gas phase and studied by both experimental (anion photoelectron spectroscopy) and theoretical (density functional calculations) methods. The photoelectron spectra of both systems are dominated by single, intense, and relatively narrow peaks. These peaks are centered at 2.63 and 2.71 eV for Cu(-)(cytidine) and Cu(-)(uridine), respectively. According to our calculations, Cu(-)(cytidine) and Cu(-)(uridine) species with these peak center [vertical detachment energy (VDE)] values correspond to structures in which copper atomic anions are bound to the sugar portions of their corresponding nucleosides largely through electrostatic interactions; the observed species are anion-molecule complexes. The combination of experiment and theory also reveal the presence of a slightly higher energy, anion-molecule complex isomer in the case of the Cu(-)(cytidine). Furthermore, our calculations found that chemically bond isomers of these species are much more stable than their anion-molecule complex counterparts, but since their calculated VDE values are larger than the photon energy used in these experiments, they were not observed. 相似文献
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Gao R Niu G Wang L Geng Y Ma B Zhu Y Dong H Qiu Y 《Physical chemistry chemical physics : PCCP》2012,14(17):5973-5978
In this paper, 8-hydroxyquinoline aluminium (Alq(3)) was used in interface modification of dye-sensitized solar cells (DSCs). Alq(3) was the first discovered interface modification material with combined effects of retarding charge recombination and F?rster resonant energy transfer (FRET). Results of dark current curve and AC impedance showed that Alq(3) could retard charge recombination in DSCs. I-V curves showed that conversion efficiency increased with Alq(3) modification. Besides the interface modification effect, it was discovered that Alq(3) also acted as energy relay dye with the FRET effect between itself and N3, which increased photoresponse and electron injection. The application of Alq(3) with combined effects opened a new door to explore more novel multi-functional interface modification materials to improve the performance of DSCs. 相似文献
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Xiaohe Wang Nana Yan Miao Xie Puxu Liu Pu Bai Haopeng Su Binyu Wang Yunzheng Wang Libo Li Tao Cheng Peng Guo Wenfu Yan Jihong Yu 《Chemical science》2021,12(25):8803
Functional nanoporous materials are widely explored for CO2 separation, in particular, small-pore aluminosilicate zeolites having a “trapdoor” effect. Such an effect allows the specific adsorbate to push away the sited cations inside the window followed by exclusive admission to the zeolite pores, which is more advantageous for highly selective CO2 separation. Herein, we demonstrated that the protonated organic structure-directing agent in the small-pore silicoaluminophosphate (SAPO) RHO zeolite can be directly exchanged with Na+, K+, or Cs+ and that the Na+ form of SAPO-RHO exhibited unprecedented separation for CO2/CH4, superior to all of the nanoporous materials reported to date. Rietveld refinement revealed that Na+ is sited in the center of the single eight-membered ring (s8r), while K+ and Cs+ are sited in the center of the double 8-rings (d8rs). Theoretical calculations showed that the interaction between Na+ and the s8r in SAPO-RHO was stronger than that in aluminosilicate RHO, giving an enhanced “trapdoor” effect and record high selectivity for CO2 with the separation factor of 2196 for CO2/CH4 (0.02/0.98 bar). The separation factor of Na-SAPO-RHO for CO2/N2 was 196, which was the top level among zeolitic materials. This work opens a new avenue for gas separation by using diverse silicoaluminophosphate zeolites in terms of the cation-tailored “trapdoor” effect.The sodium form of silicoaluminophosphate RHO zeolite exhibits a pronounced cation-tailored “trapdoor” effect, showing an unprecedented selectivity adsorption separation performance for CO2/CH4 and CO2/N2. 相似文献
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Poly(glyceryl methacrylate) (PGMA) was reacted with meso‐tetra(4‐hydroxylphenyl)porphyrin (THPP) in a homogeneous system via the ring opening reaction between epoxy and hydroxyl groups, which exist on the side chain of PGMA and the outside ring of THPP, respectively. Porphyrin‐functionalized PGMA with line‐type (denoted as HPP‐PGMA), on whose side chains hydroxylphenyl porphyrin (HPP) was bonded, was obtained. Grafting particles PGMA/SiO2 were also reacted with THPP, and the porphyrin‐immobilized particles (denoted as HPP‐PGMA/SiO2), on which HPP was supported, were produced. The above two target products were characterized using spectroscopy methods, such as infrared (IR), nuclear magnetic resonance (1H‐NMR), electronic absorption, and fluorescence emission. The effects of various factors on the bonding and immobilization reactions of HPP were studied in detail. The experimental results show that the soluble HPP‐PGMA has all the spectral characteristics of porphyrins and the absorption or emission intensity is increased with the increase in the bonding degree of HPP. In the preparation process of HPP‐PGMA, in order to avoid the occurrence of the crosslinking reaction and to obtain HPP‐PGMA with complete line‐type, the catalyst should be selected and the reaction time should be controlled. NaHCO3 is an appropriate catalyst. In the immobilization process of HPP on the grafting particle PGMA/SiO2, the greater the used amount of the catalyst triethylamine (TEA), the more rapid is the rate of ring opening reaction, resulting in higher immobilization amount of HPP. Besides, the immobilization amount of HPP is increased with the enhancement of the reaction temperature. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Chen Xi Wang Jun Huo Siqi Yang Shuang Zhang Bin Cai Haopeng 《Journal of Thermal Analysis and Calorimetry》2019,135(6):3153-3164
Journal of Thermal Analysis and Calorimetry - Novel phosphorus-contained Schiff base (PSF) is synthesized by furfurylamine, salicylaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide... 相似文献
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复合材料力矩管扭转性能的研究 总被引:1,自引:0,他引:1
为了研究缠绕角度对玻璃纤维增强复合材料管(GFRP)扭转性能的影响和给在实际应用中提供依据,本文研究采用湿法缠绕成型工艺制得了具有不同缠绕角度的GFRP管.通过测试缠绕管的破坏扭矩来分析影响复合材料缠绕管扭转性能的各项因素,并与理论计算值进行了比较.研究结果表明,缠绕管扭转破坏的主要形式为面内剪切破坏.当缠绕角度在25°至60°范围内变化时,随着缠绕角度的增大,复合材料缠绕管的壁厚逐渐减小,抗剪性能逐渐减弱且扭转破坏形式有分层情况出现.当缠绕角是25°时,缠绕管的抗扭性能最佳,最大扭矩为118N.m,对应的扭转强度为209MPa. 相似文献
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Geng Y Shi Y Wang L Ma B Gao R Zhu Y Dong H Qiu Y 《Physical chemistry chemical physics : PCCP》2011,13(6):2417-2421
Montmorillonite (MMT) added to electrolytes has been reported in the literature to facilitate the transport of I(-)/I(3)(-), and improve the ionic conductivity and consequent photocurrent of dye-sensitized solar cells (DSCs). This paper firstly observes, investigates and reports that MMT addition to a poly(ethylene oxide) (PEO)-based gel electrolyte not only improves the ionic conductivity of the gel electrolyte, but also increases the photovoltage and decreases the dark current. From the results of electrochemical impedance spectroscopy (EIS) and transient photovoltage spectra, we evidence that MMT in the polymer gel electrolyte can efficiently retard the charge recombination that occurs at the TiO(2)/dye/electrolyte interfaces. 相似文献
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Gao R Wang L Geng Y Ma B Zhu Y Dong H Qiu Y 《Physical chemistry chemical physics : PCCP》2011,13(22):10635-10640
In this paper, the interface modification effects of 4-tertbutylpyridine (TBP), especially the interaction with dye molecules, were discussed. The results of FTIR showed that TBP interacted with dye molecules, in addition to its interaction with the TiO(2) film. Reaction between N3 and TBP by the interaction force of the H atom in the -COOH group of N3 and the N atom of TBP could retard the aggregation of dye molecules, decreasing the electron quenching and charge recombination. Furthermore, the results of cyclic voltammograms and UV-vis absorption edge revealed the interaction between TBP and dye molecules could cause the energy level of the dye molecules to change, influencing the electron injection efficiency in DSCs. The IPCE results indicated that with TBP modification, the injection efficiency decreased, but the electron collection efficiency was enhanced. 相似文献