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排序方式: 共有292条查询结果,搜索用时 46 毫秒
51.
上海市食品中铝污染情况分析 总被引:9,自引:0,他引:9
为了解上海市食品中铝污染情况,采集四个品种94件样品用国标法GB/T 5009.182-2003进行了铝含量的分析。结果表明,按照国标GB 15202-1994判断,饼干合格率达100%,糕点合格率85.7%,馒头合格率81.5%,油条合格率仅53.5%。提出了控制铝污染对策和建议。 相似文献
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Yifan Zhang Dr. Yamin Zhang Yi Cao Minghao Xie Dr. Jiabao Li Alex Balzer Prof. Nian Liu Prof. Z. John Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(50):12900-12909
Spinel ferrites are promising anode materials for lithium-ion batteries (LIBs) owing to their high theoretical specific capacities. However, their practical application is impeded by inherent low conductivity and severe volume expansion, which can be surpassed by increasing the surface-to-volume ratio of nanoparticles. Currently, most methods produce spinel ferrite nanoparticles with large size and severe aggregation, degrading their electrochemical performance. In this study, a low-temperature aminolytic route was designed to synthesize sub-10 nm CoFe2O4 nanoparticles with good dispersion through carefully exploiting the reaction of acetates and oleylamine. The performance of CoFe2O4 nanoparticles obtained by a traditional co-precipitation method was also investigated for comparison. This work demonstrates that CoFe2O4 nanoparticles synthesized by the aminolytic route are promising as anode materials for LIBs. Besides, this method can be extended to design other spinel ferrites for energy storage devices with superior performance by simply changing the starting material, such as MnFe2O4, MgFe2O4, ZnFe2O4, and so on. 相似文献
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Wang Junru Zhou Yucheng Shao Yamin He Feng Wu Min Ni Henmei Zheng Yingping Sun Yueming 《Research on Chemical Intermediates》2019,45(4):1721-1735
Research on Chemical Intermediates - Hybrid materials of chitosan–silica (CS–SiO2) with nonprecious-metallic ions (Cu) immobilized on (Cu–M@CS–SiO2) were developed as green... 相似文献
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Guiqi Huang Meiling Su Wei Zhang Yamin Liu Chunyan Chen Simin Li 《Journal of separation science》2022,45(3):760-770
A series of low-cost hyper-crosslinked polymers were prepared by an easy one-step Friedel-Crafts reaction. The synthesized hyper-crosslinked polymers exhibited remarkably porous structure, large surface area, and hydroxyl groups, which can be employed as an ideal adsorbent material for novel sorbent-phase extraction techniques. Based on this, using hyper-crosslinked polymers as sorbent and coating, three novel extraction methods, including micro-solid-phase extraction, dispersive solid-phase extraction, and solid-phase microextraction, were explored and evaluated for simultaneous measurement of five endocrine-disrupting compounds (triclosan and bisphenol A, tetrabromobisphenol A, tetrabromobisphenol A bisallylether, and tetrabromobisphenol A bis(2,3-dibromopropyl ether)) in environment water prior to high-performance liquid chromatography–ultraviolet. The influence of experimental parameters on three extraction techniques such as extraction time, the amount of hyper-crosslinked polymers, extraction temperature, ionic strength, and desorption conditions were optimized. Three previously mentioned methods provided limits of detection ranging from 0.01 to 0.05 μg/L, and high recoveries (85–99%) with relative standard deviations of 1.7–5.6%. This study presented the merits and disadvantages of three proposed extraction methods and their potential for effective monitoring of hazardous pollutants in real water samples. 相似文献
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Position-dependent-mass systems are of great importance in many physical situations,such as the transport of charge carriers in semiconductors with non-uniform composition and in the theory of many-body interactions in condensed matter.Here we investigate,numerically and analytically,the phenomenon of fractional revivals in such systems,which is a generic characteristic manifested by the wave-packet evolution in bounded Hamiltonian systems.Identifying the fractional revivals using specific probe... 相似文献
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二阶梯度升温热解吸法测定空气中的微量丙烯腈和乙腈 总被引:1,自引:0,他引:1
采用气体采样泵将空气样品的丙烯腈和乙腈吸附到吸附管中,用二阶梯度升温将吸附管中的被测物质解吸到冷阱中,再快速对冷阱升温,将冷阱中的被测物质解吸进入色谱柱进行分离,用气相色谱氢火焰检测器检测空气中的微量丙烯腈和乙腈。丙烯腈、乙腈的色谱峰面积与吸附质量的线性相关系数均大于0.995。该法对实际空气样品中丙烯腈的检出限为5μg/m3,乙腈的检出限为10μg/m3,加标回收率均大于90%。 相似文献