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排序方式: 共有115条查询结果,搜索用时 15 毫秒
31.
Fan Xianyong Wang Xuesheng Chen Qingzhu 《Journal of Thermal Analysis and Calorimetry》2021,145(2):569-580
Journal of Thermal Analysis and Calorimetry - In this paper, the theoretical formulation corresponding to the thermo-hydraulic forming process was derived, and it was used for calculating the... 相似文献
32.
通过静电纺丝技术与离子溅射镀膜法,以电纺聚乙烯吡咯烷酮(PVP)为模板,制备了高透明的柔性金(Au)纳米纤维膜.研究表明,该柔性Au纳米纤维膜呈现无规网状分布,纤维的平均直径为291~322 nm.当Au的溅射时间为75 s时,所得薄膜的可见光透过率为92%,近红外反射率为7%,电阻率为2.9×10-3Ω·cm.该Au纳米纤维膜可转移到任何柔性基底上,且显示出优异的柔韧性,在弯曲500次后其电阻率基本不变. 相似文献
33.
The 1,3‐dipolar cycloaddition of an azomethine ylide generated by a decarboxylative route from sarcosine and isatin to 1‐benzyl‐3,5‐diarylmethylidene‐piperidin‐4‐ones afforded novel di‐spiro‐indolo/pyrrolidino/piperidines in moderate yields. Further cycloaddition of these di‐spiro compounds to nitrile oxide afforded tri‐spiro‐indolo/pyrrolidino/piperadino/isoxazolines in moderate yields with high regio‐ and stereoselectivity. 相似文献
34.
NMR and theoretical study on interactions between diperoxovanadate complex and pyrazole-like ligands
Xianyong Yu Ronghua Liu Hongliang Peng Haowen Huang Xiaofang Li Baishu Zheng Pinggui Yi Zhong Chen 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(3):1095-1099
To understand the effects of pyrazole substitution on reaction equilibrium, the interactions between a series of pyrazole-like ligands and [OV(O2)2(D2O)]?/[OV(O2)2(HOD)]? were explored by using multinuclear (1H, 13C, and 51V) magnetic resonance, HSQC, and variable temperature NMR in 0.15 mol/L NaCl ionic medium mimicking physiological conditions. These results show that the relative reactivities among the pyrazole-like ligands are 3-methyl-1H-pyrazole ≈ 4-methyl-1H-pyrazole ≈ 1H-pyrazole > 1-methyl-1H-pyrazole. As a result, the main factor which affects the reaction equilibrium is the steric effect instead of the electronic effect of the methyl group of these ligands. A pair of isomers has been formed resulting from the coordination of 3-methyl-1H-pyrazole and a vanadium complex, which is attributed to different types of coordination between the vanadium atom and the ligands. Thus, the competitive coordination leads to the formation of a series of six-coordinate peroxovanadate species [OV(O2)2L]? (L, pyrazole-like ligands). Moreover, the results of density functional calculations provided a reasonable explanation on the relative reactivity of the pyrazole-like ligands as well as the important role of solvation in these reactions. 相似文献
35.
36.
Yao Xu Xianyong Sun Dong Wu Yuhan Sun Yongxia Yang Hanzhen Yuan Feng Deng Zhonghua Wu 《Journal of solution chemistry》2007,36(3):327-344
In-situ
29Si liquid-state nuclear magnetic resonance (NMR) was used to investigate the ammonia catalyzed hydrolysis and condensation
of the mixed systems of tetraethoxysilane (TEOS) and dimethyldiethoxysilane (DDS) dissolved in methanol. With ammonia catalysis,
the hydrolysis reaction orders for TEOS and DDS in the mixed systems remained first order, which is similar to that observed
for their corresponding single silane component precursor systems. The hydrolysis rate constant for TEOS in the mixed systems
was larger than that of TEOS in the single silane component precursor systems. Meanwhile, the hydrolysis rate constants of
DDS in the mixed precursor systems were smaller than those of DDS in the single silane component precursor systems. The hydrolysis
and condensation kinetics showed more compatible hydrolysis-condensation relative rates between TEOS and DDS, which remarkably
affected the final microstructure of the resulting silica particles. Small angle X-ray scattering (SAXS) experiments showed
a typical double fractal structure in the particulate networks. 相似文献
37.
对新生育酚(维生素E)模型化合物(生育酚1:2,2-二甲基-4-异丙基-7-特丁基-6-色满酚),在甲苯溶剂里以过氧化二叔丁基引发产生生育酚氧自由基进行电子自旋共振(ESR)波谱测试,获得质子超精细分裂(hfs)偶合常数和giso因子值.以获得的质子超精细分裂偶合常数进行了计算机图谱模拟. 相似文献
38.
39.
Jian Chen Peisheng Zhang Xianyong Yu Xiaofang Li Hongwen Tao Pinggui Yi 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8):637-643
Novel photoswitchable fluorescent nanoparticles were fabricated by a facile one-step mini-emulsion polymerization, in which fluorescence resonance energy transfer (FRET) donor, 9,10-diphenylanthracene (DPA), and photoswitchable acceptor, spiropyran derivate, were simultaneously embedded in polymer matrix during the polymerization process. The prepared fluorescent nanoparticles exhibit the typical absorption properties of both DPA dye and spiropyran moiety, indicating that the two chromophores have been incorporated into the polymer nanoparticles. The obtained fluorescent nanoparticles exhibited superior photoswitchable fluorescent performance due to the effective photoinduced interparticle FRET. Moreover, the novel photoswitchable fluorescent nanoparticles also revealed small size (ca. 60 nm), high intensity, relatively fast photoresponsive property and good photoreversibility in aqueous media. 相似文献
40.