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61.
Khaled Osati Ali Salajegheh Mohammad Mahdavi Kamran Chapi Arash Malekian 《Isotopes in environmental and health studies》2014,50(2):169-183
Karst springs of the Zagros Mountains contribute a significant amount to agricultural and human water demands of western and south-western Iran. For an adequate management of available water resources in semi-arid and arid regions, sufficient hydrological monitoring is needed, and hydro-chemical and isotope hydrological data provide important additional information. About 350 water samples were collected from precipitation, river water, and karst springs of the upper part of the Karkheh River Basin (20,895 km2) located between 33°35′ and 34°55′ North and 46°22′ and 49°10′ East with elevations ranging from 928 to 3563 m above sea level. Sampling was conducted in monthly time resolution from August 2011 to July 2012. All samples were analysed for hydro-chemical parameters (pH, electrical conductivity, and major ions) and stable isotopes (deuterium, oxygen-18). Isotope values of precipitation indicate a local meteoric water line (Zagros MWL δ2H=6.8 δ18O+10.1; R2=0.99) situated between the Mediterranean MWL and Global MWL. Spring and river water isotope values vary between?7.1 and?4.1 ‰, and?38 and?25 ‰ for δ18O and δ2H, respectively, responding to winter snowmelt and evaporation. This work implements stable isotopes and hydro-chemical information of springs and river water to understand hydrological and hydro-geological interrelations in karstic semi-arid areas and helps to improve the current water resources management practices of western Iran. 相似文献
62.
Inside Back Cover: Plasmon‐Assisted Water Splitting Using Two Sides of the Same SrTiO3 Single‐Crystal Substrate: Conversion of Visible Light to Chemical Energy (Angew. Chem. Int. Ed. 39/2014) 下载免费PDF全文
63.
Nicolas Illy Mike Robitzer Rémi Auvergne Sylvain Caillol Ghislain David Bernard Boutevin 《Journal of polymer science. Part A, Polymer chemistry》2014,52(1):39-48
A novel, straightforward and versatile chemical pathway has been studied to functionalize water‐soluble chitosan oligomers. This metal‐free methodology is based on the epoxy‐amine reaction of the allyl glycidyl ether with chitosan, followed by thiol‐ene radical coupling reaction of ω‐functional mercaptans, using 4,4′‐Azobis(4‐cyanovaleric acid) as a free radical initiator. Both reactions were entirely carried out in water. In a preliminary step, chitosan depolymerization was carried out using H2O2 in an acetic medium under 100 W microwave irradiation, optimizing the yield of water‐soluble oligomers. Functionalization by six different thiols bearing alcohol, carboxylic acid, ester, and amino groups was then performed, leading to a range of functional oligochitosans with different grafting efficiencies. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 39–48 相似文献
64.
Interim Anatase Coating Layer Stabilizes Rutile@CrxOy Photoanode for Visible‐Light‐Driven Water Oxidation 下载免费PDF全文
Dr. Huaqiang Zhuang Dr. Jianwei Miao Dr. Haowei Huang Prof. Jinlin Long Dr. Yingguang Zhang Dr. Hongbin Yang Dr. Sha He Prof. Yanhui Yang Xuxu Wang Bin Liu 《Chemphyschem》2015,16(7):1352-1355
Ternary core–shell heterostructured rutile@anatase@CrxOy nanorod arrays were elaborately designed as photoanodes for efficient photoelectrochemical water splitting under visible‐light illumination. The four‐fold enhanced and stabilized visible‐light photocurrent highlights the unique role of the interim anatase layer in accelerating the interfacial charge transfer from the CrxOy chromophore to rutile nanorods. 相似文献
65.
Green Approach to the Fabrication of Superhydrophobic Mesh Surface for Oil/Water Separation 下载免费PDF全文
We report a simple and environment friendly method to fabricate superhydrophobic metallic mesh surfaces for oil/water separation. The obtained mesh surface exhibits superhydrophobicity and superoleophilicity after it was dried in an oven at 200 °C for 10 min. A rough silver layer is formed on the mesh surface after immersion, and the spontaneous adsorption of airborne carbon contaminants on the silver surface lower the surface free energy of the mesh. No low‐surface‐energy reagents and/or volatile organic solvents are used. In addition, we demonstrate that by using the mesh box, oils can be separated and collected from the surface of water repeatedly, and that high separation efficiencies of larger than 92 % are retained for various oils. Moreover, the superhydrophobic mesh also possesses excellent corrosion resistance and thermal stability. Hence, these superhydrophobic meshes might be good candidates for the practical separation of oil from the surface of water. 相似文献
66.
An Electron Dynamics Mechanism of Charge Separation in the Initial‐Stage Dynamics of Photoinduced Water Splitting in XMnWater (X=OH,OCaH) and Electron–Proton Acceptors 下载免费PDF全文
An electron dynamics mechanism of charge separation in the initial stage of excited‐state reactions of the class of X?Mn?OH2???A${ \to }$ X?Mn?OH???HA (X=OH or OCaH; A=N‐methylformamidine, guanidine, imidazole, or ammonia cluster) is reported. The dynamic effect of calcium doping is also revealed. This study provides a novel factor to be considered in designing efficient systems for photoinduced water splitting. 相似文献
67.
Inside Cover: Interim Anatase Coating Layer Stabilizes Rutile@CrxOy Photoanode for Visible‐Light‐Driven Water Oxidation (ChemPhysChem 7/2015) 下载免费PDF全文
68.
Magnetic mixed hemimicelles solid‐phase extraction coupled with high‐performance liquid chromatography for the extraction and rapid determination of six fluoroquinolones in environmental water samples 下载免费PDF全文
In this study, a mixed hemimicelle solid‐phase extraction method based on Fe3O4 nanoparticles coated with sodium dodecyl sulfate was applied for the preconcentration and fast isolation of six fluoroquinolones in environmental water samples before high‐performance liquid chromatography determination. The main factors affecting the extraction efficiency of the analytes, such as amount of surfactant, amount of Fe3O4 nanoparticles, extraction time, sample volume, sample pH, ionic strength, and desorption conditions, were investigated and optimized. The method has detection limits from 0.05 to 0.1 ng/mL and good linearity (r ≥ 09948) in the range 0.1–200 ng/mL depending on the fluoroquinolone. The enrichment factor is ~200. The recoveries (at spiked levels of 1, 5, and 50 ng/mL) are in the range of 79–120%. 相似文献
69.
基于非离子表面活性剂Triton X-100,以浊点萃取结合荧光光度法测定水中的苯酚,考察影响浊点萃取的各种因素。在pH=3.0的磷酸氢二钠-磷酸二氢钾缓冲溶液中,采用2.0mL Triton X-100(5%)、82℃平衡温度、8min平衡时间的条件下,苯酚被萃取到Triton X-100表面活性剂相与水相分开,用于环境水样中苯酚的测定,结果令人满意。 相似文献
70.
Dag Viktor Nilsson 《Mathematical Methods in the Applied Sciences》2017,40(4):1053-1080
We consider a two‐dimensional inviscid irrotational flow in a two layer fluid under the effects of gravity and interfacial tension. The upper fluid is bounded above by a rigid lid, and the lower fluid is bounded below by a rigid bottom. We use a spatial dynamics approach and formulate the steady Euler equations as a Hamiltonian system, where we consider the unbounded horizontal coordinate x as a time‐like coordinate. The linearization of the Hamiltonian system is studied, and bifurcation curves in the (β,α)‐plane are obtained, where α and β are two parameters. The curves depend on two additional parameters ρ and h, where ρ is the ratio of the densities and h is the ratio of the fluid depths. However, the bifurcation diagram is found to be qualitatively the same as for surface waves. In particular, we find that a Hamiltonian‐Hopf bifurcation, Hamiltonian real 1:1 resonance, and a Hamiltonian 02‐resonance occur for certain values of (β,α). Of particular interest are solitary wave solutions of the Euler equations. Such solutions correspond to homoclinic solutions of the Hamiltonian system. We investigate the parameter regimes where the Hamiltonian‐Hopf bifurcation and the Hamiltonian real 1:1 resonance occur. In both these cases, we perform a center manifold reduction of the Hamiltonian system and show that homoclinic solutions of the reduced system exist. In contrast to the case of surface waves, we find parameter values ρ and h for which the leading order nonlinear term in the reduced system vanishes. We make a detailed analysis of this phenomenon in the case of the real 1:1 resonance. We also briefly consider the Hamiltonian 02‐resonance and recover the results found by Kirrmann. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献