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排序方式: 共有115条查询结果,搜索用时 343 毫秒
31.
Shaoqing Jin Ying Zhang Fengtao Fan Zhaochi Feng Can Li 《Journal of Raman spectroscopy : JRS》2016,47(8):884-887
Electron–phonon coupling (EPC) is an important issue in semiconductor physics because of its significant influence on the optical and electrical properties of semiconductors. In this work, the EPC in wide bandgap semiconductors including hexagonal BN and AlN was studied by deep UV resonance Raman spectroscopy. Up to fourth‐order LO phonons are observed in the resonance Raman spectrum of hexagonal AlN. By contrast, only the prominent emission band near the band‐edge and the Raman band attributed to E2g mode are detected for hexagonal BN with deep UV resonance excitation. The different behavior in resonant Raman scattering between the III‐nitrides reflects their large difference in EPC. The mechanism for EPC in hexagonal BN is the short‐range deformation interaction, while that in hexagonal AlN is mainly associated with the weak long‐range Fröhlich interaction. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
32.
Rong Tian Xianbao Wang Yang Xu Shaoqing Li Li Wan Mingjian Li Jing Cheng 《Journal of nanoparticle research》2009,11(5):1201-1208
We have reported a highly efficient approach to functionalize single-walled carbon nanotubes by electrophilic addition polymerization
of 3-chloropropene under microwave irradiation. Using Lewis acids as catalysts, 3-chloropropene can undergo polymerization
followed by hydrolysis with alkaline methanol, and thus the reaction results in the attachment of polymer chains and hydroxyl
groups to the surface of the nanotubes. The resulting nanotubes were characterized with Fourier transform infrared spectroscopy,
thermogravimetric analysis, Raman spectroscopy, high-resolution transmission electron microscopy, and atomic force microscopy.
The result shows that 30 min of irradiation time is enough to bring the reaction to the end and a longer time did not improve
the degree of functionalization. 相似文献
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水稻产量要素相关性状QTL定位 总被引:3,自引:0,他引:3
为了定位水稻产量及其要素相关性状QTL并揭示各性状间相关的遗传基础,本研究以来源于杂交组合Lemont/特青的F12重组自交系群体为材料,在大田直播条件下对水稻单株产量、每穗颖花数、每穗实粒数、结实率、千粒重、始穗期、成熟期7个相关性状进行了QTL分析.共检测到22个产量要素相关性状QTL,分布于8条水稻染色体上,单个QTL的贡献率为6%~24%,单个性状QTL位点数为1~5个.共有4个染色体区段的共位点(co-located)QTL能同时影响2~4个产量要素相关性状,并且每个共位点QTL对性状作用的加性效应方向相同,其中2个增效等位基因来自Lemont,另外2个增效等位基因来自特青,这为各性状间表型相关提供了一定的遗传解释. 相似文献
35.
Lijian Jin Qiuju Qin Prof. Lihui Dong Shaoqing Liu Shangzhi Xie Jinkai Lu Aihao Xu Jiaxing Liu Hao Liu Yinchao Yao Xueyan Hou Prof. Minguang Fan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(60):14947-14963
A series of MOFs with a 6-connected spn topology were synthesized (MOF-808-(Zr, Hf), PCN-777-(Zr, Hf), MOF-818-(Zr, Hf)). Through the in situ DRIFTS of NH3 adsorption-desorption, we found that the activated catalyst mainly contains Lewis acid sites. The effects of different organic ligands on the Lewis acid of the Zr6 cluster were analyzed by XPS and NH3-TPD, and the relative Lewis acidity of the same metal was obtained: PCN-777>MOF-808>MOF-818. In the Py-FTIR results, we confirmed that MOF-818 has a higher acid site density. In the activity test, MOFs with mesoporous structure showed better catalytic activity under normal temperature and pressure. Among them, MOF-818 can still maintain a high degree of crystallinity after catalysis. Finally, we use density functional theory to propose the mechanism of the cycloaddition reaction of carbon dioxide and styrene oxide. The results show that the metal is coordinated with styrene oxide and halogens attack the β carbon of the epoxide. 相似文献
36.
Acoustic fatigue life evaluation is essential for thermal protection structures due to the severe thermo-acoustic load in service. A study on temperaturedependence of acoustic fatigue life for a C/SiC panel is presented in this paper. Effects of temperature on both the structural responses and the S-N curves are investigated. The Dirlik method is adopted to predict the fatigue life of a C/SiC panel at three different temperatures respectively. Significant differences are observed from the results of numerical simulations between the fatigue lives of the panel in the three cases. The temperature-dependence of acoustic fatigue life of a C/SiC panel is verified, and fatigue test of the material needs to be more attentively performed. 相似文献
37.
Shaoqing Liu Dr. Xueyan Hou Dr. Aihao Xu Dr. Bingxian Chu Yunxi Li Dr. Lijian Jin Jinkai Lu Prof. Dr. Lihui Dong Prof. Dr. Minguang Fan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(66):e202202105
Herein, the synthesis of a new type of catalyst, SBA−M (Schiff complex of different metal types grafted on SBA-15) based on a quaternization reaction, is described. Various amounts of ionic liquid were grafted into the pore channels of SBA-15 using the post-grafting method, which allowed the ionic liquid to be grafted into the pore channels restrictively. Notably, over six cycles, SBA−Mn (0.2) has been shown to maintain its catalytic activity and stability. In addition, a reaction mechanism for the cycloaddition of CO2 with epoxides based on density-functional theory is proposed. The cycloaddition reaction of CO2 and epoxides is an efficient way of carbon fixation. It is demonstrated that the metal coordinated with the oxygen atom of the epoxides and that a halogen attacked the carbon of epoxides. Moreover, theoretical calculations and synthesis strategy provide a new approach for CO2 conversion. 相似文献
38.
Li Wan Xianbao Wang Shimin Wang Shaoqing Li Qin Li Rong Tian Mingjian Li 《Journal of Physical Organic Chemistry》2009,22(4):331-336
The imidazole derivatives functionalized single‐walled carbon nanotubes (SWNTs) were synthesized by a diazonium‐based reaction. We have designed and synthesized two imidazole derivatives to modify SWNTs. The resulting products were characterized by Fourier transform infrared (FT‐IR) spectroscopy, Raman spectroscopy, ultraviolet visible (UV/Vis) spectroscopy, thermo gravimetric analysis (TGA), energy dispersive X‐ray spectroscopy (EDX), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Electrochemical measurements via a cyclic voltammetry method revealed that the weak intramolecular electronic interactions presented between the attached imidazole derivatives groups and the nanotubes. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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