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21.
A new copolymer, poly(methyl methacrylate-co-butyl acrylate) (P(MMA-co-BA)), was synthesized by emulsion polymerization with different mass ratio of methyl methacrylate (MMA) and butyl acrylate (BA). The membranes were prepared by phase inversion and corresponding gel polymer electrolytes (GPEs) were obtained by immersing the membrane into a liquid electrolyte. In this design, the hard monomer MMA provided the copolymer with good electrolyte uptake, while the soft monomer BA provided the GPE with strong adhesion between the anode and cathode of lithium ion battery. The properties of the resulting product were investigated by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectra, scanning electron spectroscopy, linear sweep voltammetry, thermogravimetric analysis, cyclic voltammetry, electrochemical impedance spectroscopy and charge/discharge test. The results show that the obtained GPE based on P(MMA-co-BA) with the mass ratios of MMA and BA = 6:1 exhibits good conductivity (as high as 1.2 × 10?3 S cm?1) at room temperature and high electrochemical stability (up to 4.9 V vs. Li/Li+). With the application of the polyethylene (PE)-supported GPE in Li/Li(Li0.13Ni0.30Mn0.57)O2 battery, the battery presents good cyclic stability (maintaining 95.4 % of its initial discharge capacity after 50 cycles) at room temperature. 相似文献
22.
Jianfei Lei Xiaoping Li Weishan Li Fengqiang Sun Dongsheng Lu Yuli Lin 《Journal of Solid State Electrochemistry》2012,16(2):625-632
Arrayed porous iron-doped TiO2 was prepared by sol–gel with polystyrene spheres as template and used as photocatalyst for the degradation of methyl orange.
The structure and performances of the prepared photocatalyst were characterized with X-ray diffractometer, inductively coupled
plasma-atomic emission spectrometer, scanning electron microscope, UV-visible spectrometer, and methyl orange degradation
tests. It is found that the iron dopant does not change the crystal phase of TiO2 but affects its lattice constant, optical absorption, electronic conductivity, charge-transfer resistance, and activity toward
the degradation of methyl orange. The sample doped with 0.01 wt.% Fe (based on Ti) and with smaller pore size exhibits the
better photocatalytic activity. The degradation rate of methyl orange on the sample with a pore size of 190 nm is 2.3 times
that on the undoped sample with the same pore size. 相似文献
23.
A Spectral Method for Second Order Volterra Integro-Differential Equation with Pantograph Delay 下载免费PDF全文
In this paper, a Legendre-collocation spectral method is developed for the
second order Volterra integro-differential equation with pantograph delay. We provide
a rigorous error analysis for the proposed method. The spectral rate of convergence
for the proposed method is established in both $L^2$-norm and $L^∞$-norm. 相似文献
24.
25.
Caiyun Lin Yuying Li Weishan Tang Shufeng Zhou Xiaoping Rao 《Molecules (Basel, Switzerland)》2021,26(21)
Supramolecular hydrogels have attracted great attention due to their special properties. In this research, bio-based supramolecular hydrogels were conveniently constructed by heating and ultrasounding two components of dehydroabietic acid with a rigid tricyclic hydrophenanthrene skeleton and morpholine. The microstructures and properties of hydrogels were investigated by DSC, rheology, SAXS, CD spectroscopy, and cryo-TEM, respectively. The critical gel concentration (CGC) of the hydrogel was 0.3 mol·L−1 and the gel temperature was 115 °C. In addition, the hydrogel showed good stability and mechanical properties according to rheology results. Cryo-TEM images reveal that the microstructure of hydrogel is fibrous meshes; its corresponding mechanism has been studied using FT-IR spectra. Additionally, oil-in-water gel emulsions were prepared by the hydrogel at a concentration above its CGC, and the oil mass fraction of the oil-in-water gel emulsions could be freely adjusted between 5% and 70%. This work provides a convenient way to prepare bio-based supramolecular hydrogels and provides a new method for the application of rosin. 相似文献
26.
Jin Yi Dongsheng Lu Xiaoping Li Shejun Hu Weishan Li Jianfei Lei Yuan Wang 《Journal of Solid State Electrochemistry》2012,16(2):443-448
A porous titania has been prepared by using polystyrene spheres and tri-block copolymer ((EO)20–(PO)70–(EO)20, P123) as templates, and its structure, composition, and performance as anode of lithium ion battery are characterized by
scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction, and galvanostatic charge/discharge
test. The results from SEM and TEM indicate that the prepared porous titania has a trimodal pore system, in which the pores
are in ordered arrangement and interconnected with the same pore diameter and uniform wall thickness. The charge/discharge
tests show that the battery using the prepared porous titania as anode exhibits good rate capacity and cycle stability. 相似文献
27.
A-nor-△3(5)’9(10)-estradiene-2, 17-dione 1, a potential precursor for synthesis of some new steroidal contraceptlves, was synthesized from 3Phydroxy-5a-chloro-6ß, 19-epoxy-androstane-17-one 6 as the starting rnateri-al, which is the key intermediate of steroidal contraceptive of norethindrone, in an overall yield of 25 % in 5 steps through the sequence of 5 reactions: (i) oxidative decyclization. (ii) decarboxylative cyclization, (iii) reductive decy-clization, (iv) dehydroxy methylation, (v) deacetoxylation. 相似文献
28.
29.
18-甲基-11α-羟基腺甾-4-烯-3,17-双酮是合成高效口服避孕药的重要中间体。试用黑根霉酶羟化引进11α-羟基于18-甲基-19-失碳雌甾-4-烯-3,17-双酮,得到包括该化合物在内的几种不同位置羟基产物的混合物。改用赭曲霉酶羟化同一底物也得到包括11α-羟基在内的几种不同位置羟基产物的混合物。而用赭曲霉催化羟化18-甲基-17β-羟基腺甾-4-烯-3-酮时,首次得到15α-羟化的主要产物和7β羟化的次要产物。前者可用来合成另一类高效口服避孕药△^15-D-18-甲基炔诺酮。 相似文献
30.