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排序方式: 共有646条查询结果,搜索用时 218 毫秒
1.
This review examines the most recent electrochemical developments for nitrate, nitrite and ammonium detection for on-site water monitoring. There remains a high demand for effective field-based detection of the dissolved inorganic nitrogen (DIN) analytes to aid in mitigating nitrogen loading. Electrochemical approaches show increasing potential to fill this role as advancements in nanotechnology continually improve analytical performance and on-site applicability. However, translating these improvements into the field still faces the resonating challenges of reaching analytical proficiency (selectivity, sensitivity, robustness, stability), practical end-user functionality, minimal matrix interferences and cost effectiveness. Herein, we elaborate on these challenges via a critical evaluation of current studies and examine how realistic the prospects of on-site nitrate, nitrite and ammonium are. We also present recommendations in addressing these gaps to conclude the review. 相似文献
2.
《Comptes Rendus Chimie》2015,18(6):607-610
A concise, facile and straightforward synthetic method has been described for the synthesis of 2-(3-amino-2-oxoindolin-3-yl)-3-hydroxynaphthalene-1,4-dione derivatives by a one-pot, three-component reaction of isatins, 2-hydroxy-1,4-naphthoquinone and ammonium acetate under catalyst-free conditions in ethanol. This protocol becomes highly efficient due to its mild reaction conditions, operational simplicity, and overall good to excellent yields (80–99%). 相似文献
3.
以过硫酸铵为氧化剂,通过氧化苯胺和鲁米诺混合溶液合成了聚(苯胺-鲁米诺)复合纳米线。相对于鲁米诺425 nm处的最大荧光发射波长,复合纳米线中聚鲁米诺的最大荧光发射波长明显红移到465 nm处。采用简单的滴凃方式将聚(苯胺-鲁米诺)复合纳米线修饰于石墨电极表面,形成一层稳定的聚(苯胺-鲁米诺)复合纳米线膜。此聚(苯胺-鲁米诺)纳米线膜修饰电极呈现出良好的电化学发光特性,H2O2对化学合成的聚(苯胺-鲁米诺)纳米线电化学发光呈现出增敏效应。在优化实验条件下,修饰电极的电化学发光信号与H2O2在5.0×10#9~1.0×10#5mol/L范围内呈线性关系,检出限为2×10#9mol/L。 相似文献
4.
硝酸铵的一种敏化技术 总被引:3,自引:0,他引:3
介绍一种在表面活性剂作用下,采用真空改性结晶技术,制备膨松、轻质和多微孔隙硝酸铵的方法。用该硝酸铵混制的铵木油炸药,具有良好的起爆和传爆性能、作功能力大、爆速高,是一种可以取代铵梯炸药,适宜于工业生产和广泛用于工程爆破的炸药。 相似文献
5.
Based on the mass transfer theory, a new mass transfer model of ion-exchange process on zeolite under liquid film diffusion
control is established, and the kinetic curves and the mass transfer coefficients of –K+ ion-exchange under different conditions were systemically determined using the shallow-bed experimental method. The results
showed that the –K+ ion-exchange rates and transfer coefficients are directly proportional to solution flow rate and temperature, and inversely
proportional to solution viscosity and the size of zeolite granules. It also showed that the transfer coefficient is not influenced
by the ion concentrations. For a large ranges of operational conditions including temperatures (10 − 75°C), flow rates (0.031 m s−1 −0.26 m s−1), liquid viscosities (1.002 × 10−3 N s m−2 − 4.44 × 10−3 N s m−2), and zeolite granular sizes (0.2 − 1.45 mm), the average mass transfer coefficients calculated by the model agree with the
experimental results very well. 相似文献
6.
《Tetrahedron》2014,70(52):9814-9818
New process that can selectively prepare α,α-dichloro ketones from various ketones with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) using ammonium chloride as a catalyst is reported. The effects of ammonium salts, solvents, DCDMH, and reaction temperature were investigated. Under the optimal condition, most of α,α-dichlorinated products were selectively obtained in 86–98% yield. 相似文献
7.
We demonstrate a dramatic increase in the signal-to-noise ratio (SNR) of a nuclear quadrupole resonance (NQR) signal by using a polarization enhancement technique. By first applying a static magnetic field to pre-polarize one spin subsystem of a material, and then allowing that net polarization to be transferred to the quadrupole subsystem, we increased the SNR of a sample of ammonium nitrate by one-order of magnitude. 相似文献
8.
9.
Acyclic olefinic amides were iodolactonized in the mixed solvent of CH3CN and H2O (90:102 v/v) under reflux to give products with trans configuration of the newly formed iodomethyl to the inherent alkyl group in high yield. 相似文献
10.
An integration of different modelling methods including object and mathematical simulation are suggested for sublimation processes of inorganic fluorides to optimally simulate the real technological conditions. The paper presents the results of testing this methodology on ammonium hexafluorosilicate sublimation. 相似文献