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排序方式: 共有136条查询结果,搜索用时 890 毫秒
1.
Qilong Xie Shuhui Liu Yingying Fan Jianzhi Sun Xiaoke Zhang 《Analytical and bioanalytical chemistry》2014,406(18):4563-4569
A selective and low organic-solvent-consuming method of sample preparation combined with high-performance liquid chromatography with diode-array detection is introduced for analysis of phthalic acid esters in edible oils. Sample treatment involves initial liquid–liquid partitioning with acetonitrile, then QuEChERS cleanup by dispersive solid-phase extraction with primary secondary amine as sorbent. Preconcentration of the analytes is performed by ionic-liquid-based dispersive liquid–liquid microextraction, with the cleaned-up extract as disperser solvent and 1-hexyl-3-methylimidazolium hexafluorophosphate as extraction solvent. Under the optimized conditions, correlation coefficients (r) were 0.998–0.999 and standard errors (S y/x ) were 2.67–3.37?×?103 for calibration curves in the range 50–1000 ng g?1. Detection limits, at a signal-to-noise ratio of 3, ranged from 6 to 9 ng g?1. Intra-day and inter-day repeatability, expressed as relative standard deviation, were in the ranges 1.0–6.9 % and 2.4–9.4 %, respectively. Recovery varied between 84 % and 106 %. The developed method was successfully used for analysis of the analytes in 28 edible oils. The dibutyl phthalate content of four of the 28 samples (14 %) exceeded the specific migration limit established by domestic and international regulations. Figure
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2.
Yupeng Xing Xiaoke Wang Shuhua Hao Xueli Zhang Xiao Wang Wenxuan Ma Gang Zhao Xijin Xu 《中国化学快报》2021,32(1):13-20
g-C3N4 have been widely used in the fields of photocatalytic hydrogen production,photocatalytic degradation of dyes and oxidative degradation of toxic gases due to their excellent performance.It has attracted extensive attention in recent years due to its highly efficient photocatalytic capacity of hydrogen generation,water oxidation,carbon dioxide reduction and degradation of organic pollutants.Because of the abundant carbon and nitrogen composition of the earth,large-scale production and industrial applications of this material are possible.The modification of this material makes its performance more excellent so that this new material can obtain a steady stream of vitality.These outstanding works have become important materials and milestones on the road to mankind's photocatalytic hydrogen production.This review will begin with the basic idea of designing,synthesizing and improving g-C3N4 based photocatalytic materials,and introduce the latest development of g-C3N4 photocatalysts in hydrogen production from four aspects of controlling the carbon/nitrogen ratio,morphology,element doping and heterojunction structure of g-C3N4 materials. 相似文献
3.
Single‐Layered Ultrasmall Nanoplates of MoS2 Embedded in Carbon Nanofibers with Excellent Electrochemical Performance for Lithium and Sodium Storage 下载免费PDF全文
Dr. Changbao Zhu Dr. Xiaoke Mu Prof. Peter A. van Aken Prof. Yan Yu Prof. Joachim Maier 《Angewandte Chemie (International ed. in English)》2014,53(8):2152-2156
The preparation and electrochemical storage behavior of MoS2 nanodots—more precisely single‐layered ultrasmall nanoplates—embedded in carbon nanowires has been studied. The preparation is achieved by an electrospinning process that can be easily scaled up. The rate performance and cycling stability of both lithium and sodium storage were found to be outstanding. The storage behavior is, moreover, highly exciting from a fundamental point of view, as the differences between the usual storage modes—insertion, conversion, interfacial storage—are beneficially blurred. The restriction to ultrasmall reaction domains allows for an almost diffusion‐less and nucleation‐free “conversion”, thereby resulting in a high capacity and a remarkable cycling performance. 相似文献
4.
ZIF-8是一种Zn基金属有机骨架材料, 可以吸附丙酮气体从而作为电容式丙酮传感器的气敏材料, 然而ZIF-8的传统使用形式为粉末态, 这导致其不能成为具备柔性的整体, 从而限制了传感器的柔性. 结合包埋种子和二次生长法将ZIF-8与纳米纤维结合成纤维型柔性材料, 并将其作为气敏层制备了柔性电容式丙酮气体传感器. 该传感器在9种常见挥发性有机化合物中表现出良好的选择性, 对250~2000 cm3/m3的丙酮气体具有灵敏的响应、良好的循环响应及长期稳定性. 值得注意的是该柔性传感器不仅在室温下进行传感, 而且在弯折180°的状态下对丙酮气体的响应值与不弯折(0°)状态下几乎一致, 在200次以内的180°弯折-恢复后同样表现出了传感性能的稳定, 表明了其在柔性传感器方面的潜力. 相似文献
5.
A novel electrochemical biosensor based on functionalized polypyrrole (PPy) nanotube arrays modified with a tripeptide (Gly-Gly-His) proved to be highly effective for electrochemical analysis of copper ions (Cu2+). The vertically oriented PPy nanotube arrays were electropolymerized by using modified zinc oxide (ZnO) nanowire arrays as templates which were electrodeposited on indium–tin oxide (ITO) coated glass substrates. The electrodes were functionalized by appending pyrrole-α-carboxylic acid onto the surface of polypyrrole nanotube arrays by electrochemical polymerization. The carboxylic groups of the polymer were covalently coupled with the amine groups of the tripeptide, and its structural features were confirmed by attenuated total reflection infrared (ATR-IR) spectroscopy. The tripeptide modified PPy nanotube arrays electrode was used for the electrochemical analysis of various trace copper ions by square wave voltammetry. The electrode was found to be highly sensitive and selective to Cu2+ in the range of 0.1–30 μM. Furthermore, the developed biosensor exhibited a high stability and reproducibility, despite the repeated use of the biosensor electrode. 相似文献
6.
Covalently Assembled Dipeptide Nanospheres as Intrinsic Photosensitizers for Efficient Photodynamic Therapy in Vitro 下载免费PDF全文
Xiaoke Yang Jinbo Fei Qi Li Prof. Dr. Junbai Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6477-6481
Monodispersed diphenylalanine‐based nanospheres with excellent biocompatibility are fabricated through a facile covalent reaction‐induced assembly. Interestingly, the nanospheres exhibit red autofluorescence. Most importantly, such assembled dipeptide nanospheres can serve as intrinsic photosensitizer to convert O2 to singlet oxygen (1O2). Thus, photodynamic therapy in vitro can be achieved effectively. The versatile strategy could be extended to other biomolecules containing a primary amine group for the fabrication of potential intrinsic photosensitizers. 相似文献
7.
A fiber Fabry-Perot interferometer (FFPI) sensor is formed with broadband (~3 nm, 3-dB bandwidth) fiber Bragg grating (FBG) mirrors. Repetitively modulating a distributed-feedback laser produces chirping that modulates the reflectance of the FFPI. Because the reflectance of the FBG mirrors varies with optical frequency, the fringes in the sensor reflectance modulation are distinguishable, making it possible to extend the sensor dynamic range versus that of a FFPI sensor with conventional wavelength-dependent mirrors. An ambient temperature is determined in the range from 25 to 170 degrees C with a resolution of 0.005 degrees C. 相似文献
8.
9.
A dammarane derivative dihydrojujubogenin-2-en-1-one, which possesses a skeleton and pharmacophore partially similar to those of Territrem B, a potent AChE inhibitor, was synthesized via three different paths. The anti-AChE activity of this compound and related analogue was measured. 相似文献
10.
岩相因子对煤的燃烧特性的预测 总被引:2,自引:0,他引:2
为了研究显微组分对煤及焦的燃烧特性的影响,从显微组分和煤阶的角度描述反应性能的变化。本文提出考虑显微组分和煤阶的岩相因子,较好的表示煤的类型和煤化程度对燃烧特性的影响,较前人孤立地看待显微组分和煤阶的影响量大进步。用岩相因子一煤的着火关,取得比较满意的结果。 相似文献