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991.
992.
Chun-Lin Teng Han-Xi Xiao Qing Cai Jian-Ting Tang Tie-Jun Cai 《Journal of Coordination Chemistry》2016,69(14):2148-2163
Two 3-D organic–inorganic hybrid supermolecular complexes, Na(BiHEDTA·2H2O)3(PW12O40)·2H3O (BiPW) and Na(BiHEDTA·2H2O)3(PMo12O40)·2H3O·2H2O (BiPMo) ethylenediamine tetraacetic acid (EDTA) have been synthesized by solution method and characterized by ultraviolet visible (UV–vis) spectroscopy, thermogravimetric-differential thermal analysis, photoluminescence, cyclic voltammetry, and single-crystal X-ray diffraction (XRD). XRD analysis reveals that BiPW and BiPMo are isostructural with 3-D architectures assembled by 2-D layer tetranuclear cation and a Keggin-type polyoxoanion. Although these two hybrids exhibit similar structures, the properties depend on the nature of polyoxoanion [PM12O40]3? (M = W, Mo). Under UV irradiation, BiPW and BiPMo show fast response of reversible and irreversible photochromism, respectively. BiPW exhibits excellent photocatalytic activity in degradation of methyl orange dyes under irradiation of UV–visible light. It can be reused for at least six cycles without obvious loss of activity in the degradation experiments; BiPMo shows catalytic activity in elimination of methanol. The elimination rate of methanol reaches 56.9% when the concentration of methanol is 2.3 g·m?3 and the flow velocity is 10 mL·min?1 at 100 °C. 相似文献
993.
Hui Chen Yong Lu Teng‐Teng Ong Xiao Hu Siu‐Choon Ng 《Journal of polymer science. Part A, Polymer chemistry》2009,47(8):2163-2171
Novel donor–acceptor type polymers consisting of alternating quaterthiophene and an electron withdrawing moiety, pyrazinyl or pyridinyl, have been prepared using Stille coupling approach with moderate yields. The polymers were highly soluble in common organic solvents such as tetrahydrofuran and chloroform. The structure and optical properties of the polymers were characterized by NMR, UV‐vis and fluorescence spectroscopy, and cyclic voltammetry, respectively. The polymer having pyrazine unit exhibited a red‐shift in both absorption and emission in comparison with those analogs containing pyridine because of strong electron withdrawing character of the pyrazinyl group. The polymer containing pyrazinyl as acceptor units also depicted decrease in its optical and electrochemical bandgap relative to those polymers containing 2,5‐ or 2,6‐pyridine moieties. The electrochemical behavior showed facile n‐doping and p‐doping properties of those polymers consisting of alternating quaterthiophene and the acceptor moiety. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2163–2171, 2009 相似文献
994.
A new bidesmoside triterpenoid saponin,named stauntoside C1(1) has been isolated from Stauntonia chinensis.Its structure was established by means of spectral and chemical methods. 相似文献
995.
996.
Four new eudesmane sesquiterpenoids endowed with an α,β‐unsaturated γ‐lactone five‐membered ring, serralactones A–D ( 1 – 4 , resp.), along with seven known sesquiterpenoids, were isolated from the whole plant Chloranthus serratus. Their structures and relative configurations were established on the basis of extensive spectroscopic analyses. 相似文献
997.
The nucleation of the cationic miniemulsion polymerization of octamethylcyclotetrasiloxane (D4) has been investigated in detail in this work. The particle size was traced by dynamic laser scattering in the polymerization process using different concentration of dodecylbenzenesulfonic acid (DBSA) as both the initiator and surfactant. The results reveal the progressively decreasing particle sizes with the steadily increasing monomer conversion. The descending particle sizes can be explained by the existence of homogeneous nucleation of hydroxyl-terminated polydimethylsiloxane (PDMS) oligomers in addition to the primary droplet nucleation. A linear relationship between the natural logarithm of the average particle diameter (lnd(t)) and the natural logarithm of the monomer conversion (lnf(t)) is then deduced based on the theory, which has been validated by the experimental data. The slope of lnd(t)~lnf(t) line relies on the parameter of K which is the ratio of PDMS oligomers entering water phase to all PDMS oligomers produced. The influence of DBSA concentration on the K and the fraction of homogeneous nucleation (F(H)) has been then obtained. Both of the values of K and F(H) increase with the increasing DBSA concentrations. 相似文献
998.
TEMPORAL CHARACTERIZATION OF LASER PULSES FROM JIGUANG-I LASER FACILITY WITH A COMPACT DUAL FUNCTION AUTOCORRELATOR 下载免费PDF全文
An optical pulse autocorrelator for rapid and slow scanning is described in this paper. Using an audio loudspeaker on one arm, an interferometric rapid-scanning signal of the output from a high-repetition laser oscillator is obtained. However, by adjusting the positions of the mirrors and using a step-motor on another arm, the intensity autocorrelation function of the output from a low-repetition laser amplifier can be easily measured. Using all-reflecting optics and an adequate nonlinear crystal, the whole instrument is very compact and has been used to measure sub-20 fs light pulses in both configurations with excellent agreement. In the slow-scanning configuration, a pulse train as long as 500ps has been determined. Using this autocorrelator, the home-made JIGUANG-I CPA laser facility was characterized for its pulse duration evolution. 相似文献
999.
近十年来 ,为了解决耐高温高分子材料加工温度高、熔体粘度大等问题 ,材料学家们研制和开发了一系列刚性环状齐聚物 ,如环状聚芳醚酮[1] 、环状聚芳醚砜[2 ] 和环状聚苯硫醚[3] 等 .但早期人们主要把含有刚性链段的环状齐聚物 (RCO)作为结构材料研究 .1 993年 ,Miyashita[4 ] 等发现 ,含有近似刚性的酰胺键的手性环状二苯胺低聚物具有与经典 LB分子相似的双亲性 ,可以获得手性 LB膜 .近来我们合成了一系列直径可控、含有不同活性功能基团的 RCO.RCO是一类潜力巨大的有机纳米功能材料 ,其具有以下性质 :(1 )纳米空穴直径稳定且可控 ;(2… 相似文献
1000.
Silicone surfactants containing different pendant hydrophilic groups such as diethanol tertiary amine (SHE, nonionic), diethanol
methyl quaternary amine (cationic) and triethyl quaternary amine (cationic) have been synthesized and characterized by 1H and 13C NMR and gel permeation chromatography. The solution behavior of these novel surfactants has also been investigated by surface
tension measurement and a fluorescence method. It has been observed that the surface tension of these surfactants decreases
as a function of time at a very low polymer concentration (1 × 10−4 wt%). At higher concentration (0.1 wt%), the equilibrium surface tensions reached very low values compared to that of typical
polymer surfactants, for example, poly(ethylene oxide–propylene oxide) block copolymer (EPE0.8). In addition, the low I
1/I
3 values of these silicone surfactants indicate the formation of polymer aggregates in aqueous solution, and an extremely low
I
1/I
3 value of SHE (1.06) compared to other polymeric surfactants (EPE0.8) and conventional surfactants [poly(ethylene glycol n-nonyl phenyl ethers), cetyltrimethylammonium bromide, and sodium dodecyl sulfate] indicates its stronger hydrophobicity.
Received: 15 May 2000 Accepted: 18 October 2000 相似文献