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Jingjing Zhang Xueqing Luo Xiaoxin Zhang Ying Xu Hongbo Xu Jinlong Zuo Dongmei Liu Fuyi Cui Wei Wang 《中国化学快报》2021,32(4):1442-1446
The urgent need for fresh water resource is a public issue facing the world. Solar distillation for seawater desalination is a promising freshwater production m... 相似文献
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报道了用于高功率相对论返波管振荡器的永磁体的设计和试制。以Halbach阵列结构为基础, 通过选择高性能的永磁材料, 调整磁钢的充磁方向、排列方式和尺寸, 优化设计了可用于某相对论返波管振荡器的永磁体结构, 其均匀区磁场强度0.98 T。采用粒子模拟方法, 进行了永磁体与返波管振荡器的一体化设计, 设计结果表明:器件输出功率超过1 GW, 设计的永磁体能够满足器件对磁场强度和位形的要求。对永磁体进行了试制和测试, 测试结果为:均匀区磁场0.88 T, 均匀区长110 mm, 磁体重量约306 kg。 相似文献
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In this article, the permanence and persistence for three classes time varying Lotka-Volterra ecological system are investigated by using Lyapunov stability analysis and constructing the compact set of attraction. Some examples are given to illustrate the theorems. 相似文献
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The study on the dynamic response performance of PEMFC with electrodeposited RuO_2·xH_2O-Pt/C electrode 下载免费PDF全文
Dynamic response performance of proton exchange membrane (PEM) fuel cells affects its durability and reliability significantly. In this study, electrodeposited RuO2 xH2O-Pt/C was prepared to promote the PEM fuel cell dynamic response performance. The prepared RuO2 xH2O-Pt/C was characterized by scanning electron microscopy (SEM) equipped with energy disperse spectroscopy (EDS), which shows that RuO2 xH2O was electrodeposited on the surface of Pt/C. Performance of single cells with and without RuO2 xH2O-Pt/C at the cathode under a certain operating condition was studied using cyclic voltammetry, electrochemical impedance spectra (EIS) and polarization curve techniques. When the fuel cell modified with RuO2 xH2O-Pt/C was operated at lower pressure, a faster and more stable dynamic response could be found. Modifying with RuO2 xH2O-Pt/C composite material not only slightly increases the single cell performance but also dramatically improves the dynamic response performance, revealing that RuO2 xH2O-Pt/C can buffer the voltage undershoot whenever the current increases instantly. 相似文献
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设计了一种工作在Ku波段的低磁场同轴相对论返波管。器件工作在同轴TM01近模式,采用两段式慢波结构构型,在前后段慢波结构中分别主要进行电子束调制与能量提取,以实现高效率工作。通过设计非对称反射腔,引入电子束预调制,进一步加深电子束调制深度,提高了束波互作用效率。通过调节慢波结构中间漂移段长度,进一步优化器件内部场分布,提取段慢波结构处轴向电场强度得到显著增强,器件工作效率可提升至35%。最终,当磁场强度0.6 、二极管电压490 V、二极管电流7.5 A时,获得1.27 GW微波输出,效率约35%,微波频率为14.7 GHz。 相似文献
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基于经典方法优化了组合场中基频场和低频场的强度比,利用优化后的组合场驱动一维氦原子,通过求解含时薛定谔方程研究了氦原子产生的高次谐波,其截止位置得到扩展,再考虑基频场初相位对产生高次谐波的影响,能够得到脉宽为37as的单个阿秒脉冲. 相似文献
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Z Zhang W Yang X Zou F Xu X Wang B Zhang J Tang 《Journal of colloid and interface science》2012,386(1):198-204
In this article, we propose a facile one-pot solvothermal route for synthesizing TiO(2)-graphene composite nanosheets (TGCN). In the system, ethylene glycol not only as a reducing agent can convert graphene oxide to reduced graphene oxide nanosheets, but also is employed to control the hydrolysis and condensation rates of tetrabutoxytitanium. The obtained TGCN hybrid materials are characterized by atomic force microscopy, transmission electron microscopy, UV-vis spectroscopy, Raman spectroscopy, X-ray photo-electron spectroscopy, X-ray diffraction, and thermal gravimetric analysis. It is found that the quantity of H(2)O used in the reaction is the key to obtain high-quality product. The photocatalytic activities of the products are evaluated using the photocatalytic degradation of methylene blue (MB) as a probe reaction. The results showed that the obtained TGCN have an enhanced adsorption capacity and remarkable improvements in the photodegradation rate of MB under visible light compared to P25. 相似文献