Highly ion-conductive solid polymer electrolyte (SPE) based on polyethylene (PE) non-woven matrix is prepared by filling poly(ethylene glycol) (PEG)-based crosslinked electrolyte inside the pores of the non-woven matrix. The PE non-woven matrix not only shows good mechanical strength for SPE to be a free-standing film, but also has very porous structure for high ion conductivity. The ion conductivity of SPE based on PE non-woven matrix can be enhanced by adding sufficient non-volatile plasticizer such as poly(ethylene glycol) dimethyl ether (PEGDME) into ion conduction phase without sacrificing mechanical strength. SPE with 20 wt.% crosslinking agent and 80 wt.% non-volatile plasticizer shows 3.1 × 10−4 S cm−1 at room temperature (20 °C), to our knowledge, which is the highest level for SPEs. It is also electrochemically stable up to 5.2 V and has high transference number about 0.52 due to the introduction of anion receptor as an additive. The interfacial resistance between Li electrode and SPE is low enough to perform charge/discharge test of unit cell consisting of LiCoO2/SPE/Li at room temperature. The discharge capacity of the unit cell shows 87% of theoretical value with 86% Coulombic efficiency. 相似文献
The oxidation of iron and manganese by ozone was studied in the laboratory. Model waters both with and without organic matter were used. Results showed iron to be very rapidly oxidized to an insoluble form in the absence of organic matter. However, in the presence of organic matter the iron was protected from oxidation by ozone and precipitation. The degree to which this occurred depended on the nature of the organic matter and the chemical environment at the time of mixing the iron stock and the dissolved organic matter.
Experiments with manganese allowed the determination of second order rate constants for the reaction of ozone with manganese at various pH values. The oxidation of manganese in the presence of organic matter occurred in competition with oxidation of the organic matter. As a result, high ozone doses were required to achieve the same degree of removal of manganese. An increase in bicarbonate alkalinity from 50 mg/L to 200 mg/L did not result in an acceleration of the manganese oxidation in the absence of organic matter. However, in the presence of organic matter, higher levels of bicarbonate created conditions that resulted in more complete oxidation of the manganese following total consumption of the dosed ozone. 相似文献
In this paper, a broadband dielectric resonator antenna (DRA) with a simple H‐slot feeding structure is proposed. The broad bandwidth (~45%) and uni‐directional radiation enable this DRA suitable to work as a radiation element in the construction of a beam‐scanning array with not only low frequency sensitivity which is important for accurate angle estimation of in‐coming targets, but also a wide scanning range. Moreover, stable coupling coefficients are established around all the above three resonances with respect to its corresponding feeding line, ensuring a low sidelobe level (SLL) across the whole operating frequency range. In order to realize such a DRA, a latticed rectangular structure is utilized to generate the lower two resonances, while the upper resonance is generated by its H‐shaped feeding slot. The shape of the latticed dielectric resonator is also modified according to a 3‐D printed fixing structure for an accurate installation. A 20‐element beam‐scanning prototype is demonstrated and manufactured. The range of scanning angle is from ?36° to +13° within the bandwidth of 10 to 16 GHz, corresponding to a frequency sensitivity of only 122.5 MHz/o. The achieved SLL are smaller than 19 dB for all scanning beams. The above performance indicates that, this array is very suitable for near‐range radar systems requiring an accurate angle estimation. 相似文献