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101.
Bin Huang Dongdong Yan Wensheng Fang Xianli Wang Jie Liu Daqi Zhang Qiuxia Wang Canbin Ouyang Qingli Han Xi Jin Aocheng Cao 《Journal of separation science》2020,43(8):1499-1513
The quantity of soil fumigants has increased globally that has focused attention on their environmental behavior. However, simultaneous analysis of traces of fumigant residues is often unreported because analysis methods are not readily available to measure them at low concentrations. In this study, typical solvent extraction methods were compared with headspace solid‐phase microextraction methods. Both methods can be used for simultaneously measuring the concentrations of five commonly used soil fumigants in soil or water. The solvent extraction method showed acceptable recovery (76–103%) and intraday relative standard deviations (0.8–11%) for the five soil fumigants. The headspace solid‐phase microextraction method also showed acceptable recovery (72–104%) and precision rates (1.3–17%) for the five soil fumigants. The solvent extraction method was more precise and more suitable for analyzing relatively high fumigant residue levels (0.05–5 μg/g) contained in multiple soil samples. The headspace solid‐phase microextraction method, however, had a much lower limits of detection (0.09–2.52 μg/kg or μg/L) than the solvent extraction method (5.8–29.2 μg/kg), making headspace solid‐phase microextraction most suitable for trace analysis of these fumigants. The results confirmed that the headspace solid‐phase microextraction method was more convenient and sensitive for the determination of fumigants to real soil samples. 相似文献
102.
Three new hydrogelators based on the conjugates of three naturally occurring biological building blocks: nucleobase, saccharide, and amino acids, were explored. Being synthesized via a facile solid phase peptide synthesis route, the hydrogelators self‐assemble in water to afford supramolecular nanofibers and hydrogels. Transmission electron microscopy, oscillation rheometry, and circular dichroism reveal that the hydrogels consist of largely helix‐based nanofibers of the widths of 5–12 nm and exhibit storage moduli up to 1 kPa. These hydrogelators also exhibit excellent cell‐compatibility. This work illustrates a new platform for constructing molecular soft materials for nanobiotechnology. 相似文献
103.
Seven thousand five hundred holograms are stored in 15 locations within a bar of Zn:Mn:Fe:LiNbO3, using a signal beam that propagates along the long axis of the bar. At each location, angular multiplexing is performed with the reference light changing its orientation in two-dimensional space. The same angular multiplexing is repeated at different locations along the long axis of the Zn:Mn:Fe:LiNbO3 bar. When operating as a holographic correlator, an input image is compared simultaneously with the records stored in all locations within the bar and is recalled accurately. 相似文献
104.
Rhodium‐Catalyzed Synthesis of 4‐Bromo‐1,2‐dihydroisoquinolines: Access to Bromonium Ylides by the Intramolecular Reaction of a Benzyl Bromide and an α‐Imino Carbene 下载免费PDF全文
Jun He Yinping Shi Wanli Cheng Zengming Man Dongdong Yang Prof. Dr. Chuan‐Ying Li 《Angewandte Chemie (International ed. in English)》2016,55(14):4557-4561
Highly functionalized 4‐bromo‐1,2‐dihydroisoquinolines were synthesized from readily available 4‐(2‐(bromomethyl)phenyl)‐1‐sulfonyl‐1,2,3‐triazoles. A bromonium ylide is proposed as the key intermediate, which can be formed by the intramolecular nucleophilic attack of the benzyl bromide on the α‐imino rhodium carbene formed in the presence of the rhodium catalyst. 相似文献
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108.
Niu HT Su D Jiang X Yang W Yin Z He J Cheng JP 《Organic & biomolecular chemistry》2008,6(17):3038-3040
The nucleophilic nature of cyanide is used to create a simple, sensitive, and highly effective sensor, 2-(trifluoroacetylamino)anthraquinone (2-TFAQ), for the easy "naked-eye" detection of very low concentrations of cyanide in an aqueous environment. 相似文献
109.
将磁性粒子与形状记忆聚合物复合,通过设计渐变式构型构筑了梯度形状磁性材料,并与润滑涂层相结合,制备了一种磁性润滑表面.在磁性梯度的作用下,超顺磁液滴在表面上能够自发定向运动.借助于材料形状记忆效应对表面区域形态进行可逆调控,进一步展示了超顺磁液滴自发定向运动过程中的启停开关式控制,实现了将液滴定向自发运输与启停控制相结合.考察了磁性粒子含量对材料形状记忆性能的影响,以及区域形态调控尺寸与液滴滑动性能间的相互关系.机理分析进一步阐明磁场梯度提供的定向驱动力促使液滴定向自发输运,表面区域形态控制的可逆调控则可以在液滴运动过程中增加/消除黏滞阻力,基于两种因素的协同作用,可以实现对超顺磁液滴运动的智能操控. 相似文献
110.
Xiaoran Zhang Xiaorong Zhu Shuowen Bo Chen Chen Kai Cheng Jianyun Zheng Shuang Li Xiaojin Tu Wei Chen Chao Xie Xiaoxiao Wei Dongdong Wang Yingying Liu Pinsong Chen Prof. San Ping Jiang Prof. Yafei Li Prof. Qinghua Liu Prof. Conggang Li Prof. Shuangyin Wang 《Angewandte Chemie (International ed. in English)》2023,62(33):e202305447
Electrocatalytic urea synthesis via coupling N2 and CO2 provides an effective route to mitigate energy crisis and close carbon footprint. However, the difficulty on breaking N≡N is the main reason that caused low efficiencies for both electrocatalytic NH3 and urea synthesis, which is the bottleneck restricting their industrial applications. Herein, a new mechanism to overcome the inert of the nitrogen molecule was proposed by elongating N≡N instead of breaking N≡N to realize one-step C−N coupling in the process for urea production. We constructed a Zn−Mn diatomic catalyst with axial chloride coordination, Zn−Mn sites display high tolerance to CO poisoning and the Faradaic efficiency can even be increased to 63.5 %, which is the highest value that has ever been reported. More importantly, negligible N≡N bond breakage effectively avoids the generation of ammonia as intermediates, therefore, the N-selectivity in the co-electrocatalytic system reaches100 % for urea synthesis. The previous cognition that electrocatalysts for urea synthesis must possess ammonia synthesis activity has been broken. Isotope-labelled measurements and Operando synchrotron-radiation Fourier transform infrared spectroscopy validate that activation of N−N triple bond and nitrogen fixation activity arise from the one-step C−N coupling process of CO species with adsorbed N2 molecules. 相似文献