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排序方式: 共有218条查询结果,搜索用时 17 毫秒
101.
Wei Hu Xiaoxiao Liang Xue Yang Yingxue You Qi Zhao Baijun Liu Zhaoyan Sun Yongfeng Men Guangshan Zhu Haiming Xie 《大分子材料与工程》2021,306(7):2100118
In this investigation, the sulfophenylated poly (ether ether ketone ketone) (SPEEKK) separators for lithium-ion batteries (LIBs) are prepared via electrospinning. The electrospun sulfophenylated poly (ether ether ketone ketone) membranes (es-SP) are then modified with lithium bis(trifuoro-methanesulfonyl)imide (LiTFSI) by immersing in the LiTFSI/ethanol solution to obtain the modified es-SP composite separators (es-SP-Li). SPEEKK displays excellent dimensional thermal stability, and thus the thermal shrinkage of es-SP-Li-20 (20% of LiTFSI in ethanol) composite separators is only 2% after 0.5 h at 200 °C. The strong polarity of sulfonic acid groups on SPEEKK and LiTFSI enhances the electrolyte wettability and uptake, and thus afford more Li source, so as to promote the conductivity of lithium ions in the composite separators, which in turn exhibit positive impacts on the rate and cycling stability performance of LIBs. The Li//LiFePO4 cells assembled with es-SP-Li-20 separator demonstrate excellent electrochemical stability over 170 cycles at 0.2 C with a reversible discharge capacity of 153 mAh g−1, and a promising rate capacity at 2 C. In short, the as-prepared es-SP-Li composite separators with excellent comprehensive property emerge as a promising application in LIBs. 相似文献
102.
In this paper, the exponential synchronization of dynamical network with distributed time delays is investigated. The intermittent controllers are designed to achieve the exponential synchronization. Based on the Lyapunov function method and the mathematical analysis technique, some synchronization criteria with respect to the system parameters, control gain and control rate are presented. From the criteria, for any given dynamical network, the needed values of control gains and rate can be easily estimated. Finally, two numerical simulations are performed to verify the derived theoretical results. 相似文献
103.
Ying Li Yijia Cao Zhaoyan Liu Yi Liu Quanyuan Jiang 《Computers & Mathematics with Applications》2009,57(11-12):1835
In this paper, Message Passing Interface (MPI) based parallel computation and particle swarm optimization (PSO) algorithm are combined to form the parallel particle swarm optimization (PPSO) method for solving the dynamic optimal reactive power dispatch (DORPD) problem in power systems. In the proposed algorithm, the DORPD problem is divided into smaller ones, which can be carried out concurrently by multi-processors. This method is evaluated on a group of IEEE power systems test cases with time-varying loads in which the control of the generator terminal voltages, tap position of transformers and reactive power sources are involved to minimize the transmission power loss and the costs of adjusting the control devices. The simulation results demonstrate the accuracy of the PPSO algorithm and its capability of greatly reducing the runtimes of the DORPD programs. 相似文献
104.
Bots are still a serious threat to Internet security. Although a lot of approaches have been proposed to detect bots at host or network level, they still have shortcomings. Host-level approaches can detect bots with high accuracy. However they usually pose too much overhead on the host. While network-level approaches can detect bots with less overhead, they have problems in detecting bots with encrypted, evasive communication C&C channels. In this paper, we propose EFFORT, a new host–network cooperated detection framework attempting to overcome shortcomings of both approaches while still keeping both advantages, i.e., effectiveness and efficiency. Based on intrinsic characteristics of bots, we propose a multi-module approach to correlate information from different host- and network-level aspects and design a multi-layered architecture to efficiently coordinate modules to perform heavy monitoring only when necessary. We have implemented our proposed system and evaluated on real-world benign and malicious programs running on several diverse real-life office and home machines for several days. The final results show that our system can detect all 17 real-world bots (e.g., Waledac, Storm) with low false positives (0.68%) and with minimal overhead. We believe EFFORT raises a higher bar and this host–network cooperated design represents a timely effort and a right direction in the malware battle. 相似文献
105.
本文以四氯化钛为原料,采用Sol-Gel法以浸镀方式在浮法玻璃上制备了纯TiO2膜和SiO2-TiO2混合膜。用电子探针、红外光谱仪和电子衍射仪测定了薄膜的成分分布及结构演变。用紫外-可见光光谱仪测定了样品的与反射率曲线。研究了溶液浓度、粘度、提拉速度及热处理温度等因素对镀膜质量的影响。 相似文献
106.
Zhaoyan Guo Huan Liu Congcong Jiang Ying Zhu Meixiang Wan Liming Dai Lei Jiang 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(10):2087-2095
Metal macro‐cyclic compounds have drawn considerable attention as alternative catalysts for oxygen reduction reaction. However, the continuous pyrolysis process usually needed for improving the performance of these compounds require an elevated temperature and complicated procedures, thus leading to an unpredictable transformation of the chemical structures and limiting their applications. Herein, we develop a new insight to fabricating hemin‐doped poly (3,4‐ethylenedioxythiophene) (PEDOT) with controllable three‐dimensional nanostructures via a one‐step, tri‐phase, self‐assembled polymerization routine. We demonstrate that the hemin‐induced synergistic effect results in a very high 4‐electron oxygen reduction activity, a better stability, and free from methanol crossover effects even in a neutral phosphate buffer solution (PBS). 相似文献
107.
108.
Xiaodan Zhao Zhengkun Yu Fanlong Zeng Jinzhu Chen Xiaowei Wu Sizhong Wu Wen‐Jing Xiao Zhaoyan Zheng 《Advanced Synthesis \u0026amp; Catalysis》2005,347(6):877-882
Reactions of selenium with imines (RR1CNR2) of aldehydes and ketones in the presence of carbon monoxide, water and triethylamine lead to reductive selenation, on aerobic work‐up, to afford symmetrical diselenides (RR1CHSe)2 in good to excellent yields. The proposed mechanism suggests that both in situ generated carbonyl selenide (SeCO) and hydrogen selenide (H2Se) are involved in the reaction. 相似文献
109.
结构安全性是结构可靠性最主要的要求,对现役框架结构及时地做出安全性评定,在安全的前提下延长其使用寿命,具有一定的社会意义和经济效益。结合改扩建工程实际情况,运用理论知识分析了现役框架结构的安全性,利用有限元SAP2000对原有结构和改建结构进行模态分析,通过对影响结构安全性的指标进行对比得出改建后的框架结构比原框架结构的安全性有一定提高。 相似文献
110.
Self-assembly of linear ABC coil-coil-rod triblock copolymers 总被引:1,自引:0,他引:1
Self-assembly of linear ABC coil-coil-rod triblock copolymer melt is studied by applying self-consistent-field lattice techniques in three-dimensional (3D) space. In contrast to rod-coil diblock copolymers, our results reveal the effect of the broad parameter space on the self-assembly of the linear ABC coil-coil-rod triblock copolymers. Seven stable structures are found stable, including “two-color” lamella, “three-color” lamella, “two-color”-perforated lamella, “three-color”-perforated lamella, core-shell hexagonal lattice phase, strip, and micelle. When the two coil blocks have equal lengths (fA = fB), the lamellar structure dominates the majority of the phase diagram. The effects of the two coil blocks on the self-assembly are explored by tuning the relative length of the A and B coil blocks in terms of keeping the length of the block C (rod). Moreover, by switching the position of the blocks B and C, the influence of the block sequencing on the self-assembly is studied. 相似文献