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921.
Asakura H Teramura K Shishido T Tanaka T Yan N Xiao C Yao S Kou Y 《Physical chemistry chemical physics : PCCP》2012,14(9):2983-2990
A combination of in situ time-resolved DXAFS and ICP-MS techniques reveals that the formation process of Rh nanoparticles (NPs) from rhodium trichloride trihydrate (RhCl(3)·3H(2)O) in ethylene glycol with polyvinylpyrrolidone (PVP) at elevated temperature is a first-order reaction, which indicates that uniform size Rh NPs appear consecutively and these Rh NPs do not aggregate with each other. 相似文献
922.
毛细管气相色谱法快速测定羰基合成脂肪醇中的正构醇 总被引:1,自引:0,他引:1
The normal alcohols in fatty alcohols produced from hydroformylation unit were determined directly byOV-1 capillary GC method; This method is simple,rapid and accurate。The relative error is below 2%andcoefficient of variation is below 3%。 相似文献
923.
Yu‐Biao Chen Yao Kang Ye‐Yan Qin Zhao‐Ji Li Jian‐Kai Cheng Yuan‐Gen Yao 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(6):m263-m265
The title compound, [Ag2(NO3)2(C5H5NS)]n, was obtained from the reaction of silver nitrate with bis(4‐pyridyl) disufide (4‐PDS) in a mixture of ethanol and water, which suggests that the disulfide bond of 4‐PDS can be cleaved under mild conditions. The structure of the title compound is a two‐dimensional infinite array in which the asymmetric unit contains two Ag atoms, a pyridinium‐4‐thiolate molecule and two nitrate groups. Each pyridinium‐4‐thiolate molecule acts as a μ4 bridge, linking four Ag atoms, with Ag—S bond distances of 2.4870 (19), 2.5791 (19), 2.5992 (19) and 2.848 (2) Å. The Ag⋯Ag distances lie in the range 2.889 (2)–3.049 (1) Å. 相似文献
924.
Zhiguo Sun Huijuan Zhang Linlin Cao Xiaokang Liu Dan Wu Xinyi Shen Xue Zhang Zihang Chen Sen Ru Xiangyu Zhu Zhiyuan Xia Qiquan Luo Faqiang Xu Prof. Tao Yao 《Angewandte Chemie (International ed. in English)》2023,62(13):e202217719
The construction and understanding of synergy in well-defined dual-atom active sites is an available avenue to promote multistep tandem catalytic reactions. Herein, we construct a dual-hetero-atom catalyst that comprises adjacent Cu-N4 and Se-C3 active sites for efficient oxygen reduction reaction (ORR) activity. Operando X-ray absorption spectroscopy coupled with theoretical calculations provide in-depth insights into this dual-atom synergy mechanism for ORR under realistic device operation conditions. The heteroatom Se modulator can efficiently polarize the charge distribution around symmetrical Cu-N4 moieties, and serve as synergistic site to facilitate the second oxygen reduction step simultaneously, in which the key OOH*-(Cu1-N4) transforms to O*-(Se1-C2) intermediate on the dual-atom sites. Therefore, this designed catalyst achieves satisfied alkaline ORR activity with a half-wave potential of 0.905 V vs. RHE and a maximum power density of 206.5 mW cm−2 in Zn-air battery. 相似文献
925.
Kun Nie Tao Feng FengKui Song Yong Zhang HongMei Sun Dan Yuan YingMing Yao Qi Shen 《中国科学:化学(英文版)》2014,57(8):1106-1116
A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL(THF)n]2 [Ln = Y(1), Yb(2), Sm(3)(n = 1) and La(4)(n = 2), L = Me2NCH2CH2N{CH2-(2-O–C6H2–tBu2-3,5)}2] and alkoxides p-C6H4CH2[OLnL(THF)]2 [Ln = Y(5), Yb(6)] supported by an amine-bridged bis(phenolate) ligand have been synthesized through one-pot reactions of Ln(C5H5)3(THF), LH2 with p-benzenediol and 1,4-benzenedimethanol, respectively. All complexes have been fully characterized by elemental analyses, single-crystal X-ray diffraction analysis, and IR and multi-nuclear NMR spectroscopy(in the cases of 1, 4 and 5). Study of their catalytic behavior revealed that, in general, all complexes are efficient initiators for the polymerization of rac-lactide(LA) and rac-β-butyrolactone(BBL), except for 3 and 4 in the case of BBL. The influence imposed by lanthanides of different ionic radii and initiating groups of different structures on the activity, controllability, and stereoselectivity of polymerization were systematically studied and compared. Highly heterotactic PLA(Pr up to 0.99) and syndiotactic PHB(Pr ≈ 0.81) with high molecular weight and narrow polydispersity formed and were automatically capped with hydroxyl functionality at both ends. 相似文献
926.
Hu Yang Weisi Yin Xuxin Kong Min Xu Yefeng Yao Qun Chen Rongshi Cheng 《Colloid and polymer science》2006,284(8):935-940
The compact single-chain (SC) particulates of Poly(N-isopropylacrylamide) (PNIPAM), which have been formed above its lower critical solution temperature in an aqueous solution containing the surfactant of sodium n-dodecyl sulfate (SDS), were recovered from the solution by freeze-drying. Under scanning electron microscopy, the compact particulate appears as a spherical or elliptical particulate individually dispersed in SDS, which acts as a solid solvent to prevent agglomeration. The conformation of the compact SC particulates of PNIPAM dispersed in SDS had been studied by the solid-state high-resolution 13C NMR spectroscopy. The 13C spin-lattice relaxation time T
1 of the SC sample was determined in comparison with that of the original one. It was found that the T
1 of the methyl carbon in the isopropyl group of the SC sample was about 45% higher than that in the original multichain sample, which revealed the differences in the motion of the methyl group in the different condensed states and illuminated the characteristic conformation of the compact SC globular particulates of PNIPAM. 相似文献
927.
A THEORY OF EFFECTIVE THERMAL CONDUCTIVITY FOR MATRIX-INCLUSION- MICROCRACK THREE-PHASE HETEROGENEOUS MATERIALS BASED ON MICROMECHANICS 总被引:1,自引:0,他引:1
The effective thermal conductivity of matrix-inclusion-microcrack three-phase heterogeneous materials is investigated with
a self-consistent micromechanical method (SCM) and a random microstructure finite element method(RMFEM). In the SCM, microcracks
are assumed to be randomly distributed and penny-shaped and inclusions to be spherical, the crack effect is accounted for
by introducing a crack density parameter, the effective thermal conductivity is derived which relates the macroscopic behavior
to the crack density parameter. In the RMFEM, the highly irregular microstructure of the heterogeneous media is accurately
described, the interaction among the matrix-inclusion-microcracks is exactly treated, the inclusion shape effect and crack
size effect are considered. A Ni/ZrO2 particulate composite material containing randomly distributed, penny-shaped cracks is examined as an example. The main results
obtained are: (1) the effective thermal conductivity is sensitive to the crack density and exhibits essentially a linear relationship
with the density parameter; (2) the inclusion shape has a significant effect on the effective thermal conductivity and a polygon-shaped
inclusion is more effective in increasing or decreasing the effective thermal conductivity than a sphere-shaped one; and (3)
the SCM and RMFEM are compared and the two methods give the same effective property in the case in which the matrix thermal
conductivity λ1 is greater than the inclusion one λ2. In the inverse case of λ1 < λ2, the two methods agree as the inclusion volume fraction and crack density are low and differ as they are high. A reasonable
explanation for the agreement and deviation between the two methods in the case of λ1 < λ2 is made.
This work was supported by the National Natural Science Foundation of China and Chnese “863” High-Tech, Program. 相似文献
928.
B. Q. Yao X. L. Liu B. S. Chen L. X. Yu X. H. Sun Z. Y. Chen Y. L. Ju Y. Z. Wang 《Laser Physics》2012,22(3):544-546
A resonantly pumped Q-switched Er:YAG laser at 1645 nm was reported. 1 mJ of output pulse energy was achieved for Q-switched
operation at 100 Hz repetition rate under total incident pump power of 4 W. An output peak power of 14 kW and pulse width
of 60.6 ns were obtained. 相似文献
929.
Yikai Chen Douguo Zhang Dong Qiu Liangfu Zhu Sisheng Yu Peijun Yao Pei Wang Hai Ming Ramachandram Badugu Joseph R. Lakowicz 《Laser \u0026amp; Photonics Reviews》2014,8(6):933-940
The unique optical properties of Tamm plasmons (TPs) – such as flexible wavevector matching conditions including inplane wavevector within the light line, and existing both S‐ and P‐polarized TPs − facilitate them for direct optical excitation. The Tamm plasmon‐coupled emission (TPCE) from a combined photonic–plasmonic structure sustaining both surface plasmons (SPs) and TPs is described in this paper. The sensitivity of TPCE to the emission wavelength and polarization is examined with back focal plane imaging and verified with the numerical calculations. The results reveal that the excited probe can couple with both TPs and SPs, resulting in surface plasmon‐coupled emission (SPCE) and TPCE, respectively. The TPCE angle is strongly dependent on the wavelength allowing for spectral resolution using different observation angles. These Tamm structures provide a new tool to control the optical emission from dye molecules and have many potential applications in fluorescence‐based sensing and imaging. 相似文献
930.
Weili YAO 《Frontiers of Mathematics in China》2012,7(4):765-783
In this paper, we establish a new estimate on exponential sums by using the Bombieri-type theorem and the modified Huxley-Hooley contour. We also generalize the famous Goldbach-Vinogradov theorem, via different argument from that of Vinogradov. In particular, our major arcs are quite large and these enlarged major arcs are treated by the estimate we have established. 相似文献