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121.
Kumondai K Toyoda M Ishihara M Katakuse I Takeuchi T Ikeda M Iwamoto K 《The Journal of chemical physics》2005,123(2):24314
The reaction mechanisms of silver trimer cation, Ag3+, with 12-crown-4 (12C4) were studied experimentally and theoretically. Using a cylindrical ion trap time-of-flight mass spectrometer, gas-phase ion/molecule reactions of Ag3+ with 12C4 were observed. Metal-ligand complexes of [Ag(12C4)]+, [Ag3(12C4)]+ and [Ag3(12C4)2]+, and of [Ag(12C4)2]+ and [Ag3(12C4)3]+, were observed as the reaction intermediates and terminal products, respectively. The formations of the [Ag12C4]+ and [Ag(12C4)2]+ complexes indicated that the neutral dimer (Ag2) had been eliminated from the trimer cation. From the results of ab initio calculations at the HF/LanL2DZ level of theory and the experiments, it is suggested that three 12C4 molecules can attach to Ag3+ through consecutive reactions and that neutral Ag2 can be easily eliminated from [Ag3(12C4)]+. 相似文献
122.
123.
Xinjian Yi Zhihong Mai Xinrong Zhao Fangqiao Zhou Luqin Liu 《International Journal of Infrared and Millimeter Waves》1996,17(4):705-710
8-element linear array IR detectors based on high Tc superconducting films have been fabricated. The thin films were deposited by magnetron sputtering onZrO
2 substrates and patterned by standard photolithographic technique forming microbridge structure. An average detectivity of 1.85 × 109
cmHz
1/2 W–1 with a variance of less than 20% in the detector-to-detector detectivity of the array has been obtained at the operating temperature of 84K. A bolometric response mechanism has been discussed. 相似文献
124.
125.
Mai Gehrke John Harding Yde Venema 《Transactions of the American Mathematical Society》2006,358(2):573-590
Let be a variety of monotone bounded lattice expansions, that is, bounded lattices endowed with additional operations, each of which is order preserving or reversing in each coordinate. We prove that if is closed under MacNeille completions, then it is also closed under canonical extensions. As a corollary we show that in the case of Boolean algebras with operators, any such variety is generated by an elementary class of relational structures.
Our main technical construction reveals that the canonical extension of a monotone bounded lattice expansion can be embedded in the MacNeille completion of any sufficiently saturated elementary extension of the original structure.
126.
127.
Carbon nanotubes (CNTs) were controllably coated with the uninterrupted CuO and CeO2 composite nanoparticles by a facile pyridine-thermal method and the high catalytic performance for CO oxidation was also found. The obtained nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction as well as X-ray photoelectron spectroscopy. It is found that the CuO/CeO2 composite nanoparticles are distributed uniformly on the surface of CNTs and the shell of CeO2/CuO/CNT nanocomposites is made of nanoparticles with a diameter of 30-60 nm. The possible formation mechanism is suggest as follows: the surface of CNTs is modified by the pyridine due to the π-π conjugate role so that the alkaline of pyridine attached on the CNT surface is more enhanced as compared to the one in the bulk solvent, and thus, these pyridines accept the proton from the water molecular preferentially, which result in the formation of the OH− ions around the surface of CNTs. Subsequently, the metal ions such as Ce3+ and Cu2+ in situ react with the OH− ions and the resultant nanoparticles deposit on the surface of CNTs, and finally the CeO2/CuO/CNT nanocomposites are obtained. The T50 depicting the catalytic activity for CO oxidation over CeO2/CuO/CNT nanocomposites can reach ∼113 °C, which is much lower than that of CeO2/CNT or CuO/CNT nanocomposites or CNTs. 相似文献
128.
Amorphous carbon nitride (a-CNx) films with functional gradient Ti-TiN/CNx underlayer were deposited by direct current magnetron sputtering. Microstructure and composition of the films were characterized by means of X-ray diffraction (XRD), Raman spectroscopy, atomic force microscope (AFM) and transmission electron microscopy (TEM). Mechanical and tribological properties were investigated by nanoindenter, scratch and ball-on-disk tribometer. The a-CNx-based films suffer a graphitization process with the increasing deposition temperature, thus the hardness and elastic modulus decrease. With the design of the Ti-TiN/CNx gradient underlayers, some important advantages of relatively thick CNx films can be achieved, such as increased hardness, improved adhesion strength, and the wear resistance of the a-CNx-based films can be also improved significantly. 相似文献
129.
Periodica Mathematica Hungarica - Let D be a division ring with infinite center, K a proper division subring of D and N an almost subnormal subgroup of the multiplicative group $$D^*$$ of D. The... 相似文献
130.
A series of novel star-shaped porphyrin-triarylamine conjugates were synthesized by palladium-catalyzed cross-coupling reactions. The spectroscopic and electrochemical studies show that pi-conjugation of the porphyrin core is extended to the triarylamine moieties. 相似文献