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Ionics - Exploration of high-rate lithium-ion batteries (LIBs) still remains a great challenge because of the ineffective charge transfer in electrode materials. In this work, the one-dimensional... 相似文献
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Zhou Huilian Yan Siming He Yi Xiang Yuxin Li Hongjie Song Ruxia Cheng Xinyu Yan Liping Song Jinxue Shangguan Jianxin 《Journal of Solid State Electrochemistry》2022,26(11):2515-2525
Journal of Solid State Electrochemistry - There are two key factors in the fabrication of superhydrophobic surfaces. One is to have the appropriate micro/nano structure, and the other is to reduce... 相似文献
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Sample pretreatment before chromatographic analysis is the most time consuming and error prone part of analytical procedures, yet it is a key factor in the final success of the analysis. A quantitative and fast liquid phase microextraction technique termed as gas purge microsyringe extraction (GP-MSE) has been developed for simultaneous direct gas chromatography-mass spectrometry (GC-MS) analysis of volatile and semivolatile chemicals without cleanup process. Use of a gas flowing system, temperature control and a conventional microsyringe greatly increased the surface area of the liquid phase micro solvent, and led to quantitative recoveries of both volatile and semivolatile chemicals within short extraction time of only 2 min. Recoveries of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and alkylphenols (APs) determined were 85-107%, and reproducibility was between 2.8% and 8.5%. In particular, the technique shows high sensitivity for semivolatile chemicals which is difficult to achieve in other sample pretreatment techniques such as headspace-liquid phase microextraction. The variables affecting extraction efficiency such as gas flow rate, extraction time, extracting solvent type, temperature of sample and extracting solvent were investigated. Finally, the technique was evaluated to determine PAHs, APs and OCPs from plant and soil samples. The experimental results demonstrated that the technique is economic, sensitive to both volatile and semivolatile chemicals, is fast, simple to operate, and allows quantitative extraction. On-site monitoring of volatile and semivolatile chemicals is now possible using this technique due to the simplification and speed of sample treatment. 相似文献
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Cui Yang Jinxue QiuChunyan Ren Xiangfan PiaoXifeng Li Xue WuDonghao Li 《Journal of chromatography. A》2009,1216(45):7694-7699
There is a trend towards the use of enrichment techniques such as microextraction in the analysis of trace chemicals. Based on the theory of ideal gases, theory of gas chromatography and the original headspace liquid phase microextraction (HS-LPME) technique, a simple gas flow headspace liquid phase microextraction (GF-HS-LPME) technique has been developed, where the extracting gas phase volume is increased using a gas flow. The system is an open system, where an inert gas containing the target compounds flows continuously through a special gas outlet channel (D = 1.8 mm), and the target compounds are trapped on a solvent microdrop (2.4 μL) hanging on the microsyringe tip, as a result, a high enrichment factor is obtained. The parameters affecting the enrichment factor, such as the gas flow rate, the position of the microdrop, the diameter of the gas outlet channel, the temperatures of the extracting solvent and of the sample, and the extraction time, were systematically optimized for four types of polycyclic aromatic hydrocarbons. The results were compared with results obtained from HS-LPME. Under the optimized conditions (where the extraction time and the volume of the extracting sample vial were fixed at 20 min and 10 mL, respectively), detection limits (S/N = 3) were approximately a factor of 4 lower than those for the original HS-LPME technique. The method was validated by comparison of the GF-HS-LPME and HS-LPME techniques using data for PAHs from environmental sediment samples. 相似文献
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Jinxue Guo Xiaoyu Zhou Lei Chen Yibin Lu Xiao Zhang Wanguo Hou 《Journal of nanoparticle research》2012,14(7):1-6
ZnO nanostructures, including nanowires, nanorods, and nanoneedles, have been deposited on GaAs substrates by the two-step chemical bath synthesis. It was demonstrated that the O2-plasma treatment of GaAs substrates prior to the sol?Cgel deposition of seed layers was essential to conformally grow the nanostructures instead of 2D ZnO bunches and grains on the seed layers. Via adjusting the growth time and concentration of precursors, nanostructures with different average diameter (26?C225?nm), length (0.98?C2.29???m), and density (1.9?C15.3?×?109?cm?2) can be obtained. To the best of our knowledge, this is the first demonstration of ZnO nanostructure arrays grown on GaAs substrates by the two-step chemical bath synthesis. As an anti-reflection layer on GaAs-based solar cells, the array of ZnO nanoneedles with an average diameter of 125?nm, a moderate length of 2.29???m, and the distribution density of 9.8?×?109 cm?2 has increased the power conversion efficiency from 7.3 to 12.2?%, corresponding to a 67?% improvement. 相似文献
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研完了邻{2-[α-(2-羟基-5-磺基苯偶氮)-亚苄基]-肼基}苯甲酸(锌试剂,ZcN)与L-粕氨酸(L-Lys)复合物的吸光光度测定基本条件,在pH1.9的缓冲溶液中,ZCN与Lys结合生成紫红色复合物,最大吸收波长在605nm处,标准工作曲线在5.47×10-6~1.64×l0-4mol·L-1范围内呈线性关系。在最大吸收峰处比锌试剂本身红移145nm,复合物的表观摩尔吸光系数ε为2.5×104。同时,研完了离子强度对反应体系的影响.ZCN作为光谱探针与Lys的结合数。 相似文献
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Three-dimensional Co3O4-graphene frameworks (3D-CGFs) are prepared with a one-pot hydrothermal method. Co3O4 particles are in situ anchored on graphene sheets, and the resulting composite self-assembles into 3D architecture during the hydrothermal treatment. Scanning electron microscope, transmission electron microscope, powder X-ray powder diffraction, and Raman spectroscopy are employed to characterize the sample. When tested as anode materials for lithium-ion batteries, 3D-CGFs demonstrate remarkable electrochemical lithium storage properties, such as large and stable reversible capacity (>530 mAh g?1 at 500 mA g?1 over 300 cycles), good capacity retention (88 % retention after 300 cycles at 500 mA g?1 compared with the 4th cycle), excellent high-rate performance (515 mAh g?1 at 1 A g?1), making it a promising candidate for high-performance anode materials, especially for high-rate lithium-ion batteries. 相似文献
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Time-resolved (or time-gated) luminescence detection technique using lanthanide chelates as luminescent probes is a widely used and highly sensitive method for the biological applications. The developments of various functional lanthanide probes that can selectively recognize the biological targets are the essential objective of the technique. In this work, a unique Tb3+ chelate-based luminescent probe, N,N,N1,N1-[2,6-bis(3′-aminomethyl-1′-pyrazolyl)-4-(p-aminophenoxy)methylene-pyridine] tetrakis(acetate)-Tb3+(BMPTA-Tb3+), has been designed and synthesized for highly selective and sensitive time-resolved luminescence detection of one highly reactive oxygen species (ROS), hydroxyl radical (OH). The probe is almost non-luminescent, and can selectively react with hydroxyl radical to afford a highly luminescent Tb3+ chelate, N,N,N1,N1-[2,6-bis(3′-aminomethyl-1′-pyrazolyl)-4-hydroxymethyl-pyridine] tetrakis(acetate)-Tb3+ (BHTA-Tb3+), accompanied by a 49-fold increase in luminescence quantum yield with a long luminescence lifetime (2.76 ms). The luminescence response of the probe to hydroxyl radical is highly selective and insensitive to pH in the physiological pH range. For loading the probe into the living cells, the acetoxymethyl ester of BMPTA-Tb3+ was synthesized and used for the HeLa cell loading. Based on this probe, a background-free time-resolved luminescence imaging method for detecting hydroxyl radical in living cells was successfully established. 相似文献
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建立了DF化学激光器压力恢复系统扩压器的流场仿真模型,对扩压器流场结构进行了仿真分析。结果显示,扩压器超扩段长度为1310 mm时,激光器可工作压力为7.18 kPa。增加超扩段长度至1810 mm,激光器的可工作压力上升至8.25 kPa; 插入2片楔形叶片,激光器的可工作压力提升至8.52 kPa。适当增加超扩段长度和插入叶片的方式可在一定范围内提高激光器的工作压力,研究结果对于化学激光器扩压器的设计与优化具有重要的参考价值。 相似文献