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991.
Lei Qiao Chao Zhang Xiang‐Wen Zhang Zi‐Chuan Wang Haolin Yin Zhong‐Ming Sun 《中国化学》2020,38(3):295-304
The polypnictide complexes of rare earth cations have drawn the attention of the scientific community for their uncommon bonding modes and potential applications. Herein, we present a systematic and comprehensive summary on recent advances in the field of rare earth polypnictides, focusing on their synthesis, structures, and reactivities. The structural stabilizing effects imposed by the electropositive rare earth cations as well as the reducing capability of rare earth precursors in the synthesis of these polypnictide complexes are described in this review. We also disscuss in detail the bonding interactions and coordination modes between rare earth cations and polypnictide clusters as well as the similarities and the peculiarity of some structures. 相似文献
992.
993.
994.
Shanfeng Wang 《European Polymer Journal》2004,40(6):1163-1167
A new conjugated polymer poly(benzobisoxazole-2,6-diylvinylene) (PBOV) has been synthesized as an analogue of poly(p-phenylene benzobisoxazole) (PBO). The comparison between PBOV and PBO has been carried out by Fourier transform infrared spectroscopy, thermogravimetric analysis, UV, and photoluminescence (PL) spectroscopy. The UV absorption peaks, PL excitation and emission wavelengths of PBOV have a significant red-shift due to the better electronic delocalization. Similar to PBO, it can be observed in the PL spectra of PBOV at various concentrations in methanesulfonic acid (MSA) that the intensity of emission was depressed and the highly structured emission spectra gradually changed to featureless, red-shifted, and broad spectra with increasing concentration. The change in emission spectra can be attributed to the existence of the interchain aggregates, although PBOV does not show highly ordered structure as PBO does. 相似文献
995.
996.
997.
Xie M Liu HH Chen P Zhang ZL Wang XH Xie ZX Du YM Pan BQ Pang DW 《Chemical communications (Cambridge, England)》2005,(44):5518-5520
A simple and convenient method for the construction of CdSe/ZnS-labeled polysaccharides as bioprobes were developed, which are highly biocompatible and photostable, and have been proven to be suitable for live cell imaging. 相似文献
998.
Zhang X Grimes BA Wang JC Lacki KM Liapis AI 《Journal of colloid and interface science》2004,273(1):22-38
In this work, an analysis of the parametric sensitivity of the overshoot in the concentration of the adsorbate in the adsorbed phase, which occurs under certain conditions during an ion-exchange adsorption process, is presented and used to suggest practical implications of the concentration overshoot phenomenon on operational policies and configurations of chromatographic columns and finite bath adsorption systems. The results presented in this work demonstrate and explain how the development of an overshoot in the concentration of the adsorbate in the adsorbed phase could be enhanced or suppressed by (i) varying the diffusion coefficient, D3, of the adsorbate relative to the diffusion coefficients, D1 and D2, of the cations and anions, respectively, of the background/buffer electrolyte, (ii) altering the initial surface charge density, delta0, of the charged adsorbent particles, (iii) varying the Debye length, lambda, and (iv) changing the initial concentration, Cd3(0), of the adsorbate in the bulk liquid of the finite bath. The influence of the pH and ionic strength, Iinfinity, of the liquid solution on the development of an overshoot in the concentration of the adsorbate in the adsorbed phase is also presented and discussed through the relationships of these parameters to delta0 and lambda, respectively. Furthermore, a detailed explanation of the effects of each parameter on the interplay between the diffusive and electrophoretic molar fluxes, as well as on the structure and functioning of the electrical double layer, which are responsible for the concentration overshoot phenomenon, is presented. 相似文献
999.
1000.
目视催化褪色计时法测定超痕量钒的研究 总被引:6,自引:1,他引:6
本文基于在酸性介质中钒(V)催化溴酸钾氧化酸性铬蓝K褪色的新指示反应,建立了一个催化褪色计时法测定超痕量钒的新方法。在体系中引入活化剂抗坏血酸,灵敏度达2×10~(-12)ng/ml,测定范围在0.0l~3.0ng/ml,同时探讨了反应机理。确立了反应速率方程,方法简便经济,已用于天然水中痕量钒的测定。 相似文献