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排序方式: 共有452条查询结果,搜索用时 15 毫秒
411.
Mojtaba Shamsipur Mehran JavanbakhtVito Lippolis Alessandra GarauGreta De Filippo Mohammad Reza GanjaliAbdullah Yari 《Analytica chimica acta》2002,462(2):225-234
Novel polymeric membrane (PME) and coated graphite (CGE) silver-selective electrodes based on two recently synthesized mixed azathioether crowns containing a 1,10-phenanthroline sub-unit were prepared. The electrodes reveal a Nernstian behavior over quite wide Ag+ ion concentration ranges with a very low limits of detection (LOD) (i.e. down to 1.0×10−8 M for CGEs and 8.0×10−7 M for PMEs). The potentiometric responses are independent of the pH of the test solution in the pH range 3.0-7.0. The electrodes possess advantages of low resistance, very fast response time, relatively long lifetimes and, especially, good selectivities relative to a wide variety of other cations. The electrodes were used, as indicator electrodes, in the potentiometric titration of silver ion and in the determination of Ag+ in waste water, photographic emulsion and radiographic and photographic films. 相似文献
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414.
Roya Azadi Babak Mokhtari Hanifeh Oghabi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1377-1382
Abstract A mild and operationally simple method for the synthesis of thiocyanohydrins is described. Mukaiyama reagent is used as an effective reagent for the solvent-free conversion of epoxides into their corresponding thiocyanohydrins. The reactions were completed in <5 min to give thiocyanohydrins with perfect regioselectivity and isolated yields. 相似文献
415.
CO2 reforming of methane (CDRM) was carried out over MgO supported Ni catalysts with various Ni loadings. The preparation of MgO supported Ni catalysts via surfactant-assisted precipitation method led to the formation of a nanocrystalline carrier for nickel catalysts. The synthesized samples were characterized by XRD, N2 adsorption-desorption, H2 chemisorption, TPR, TPO and SEM techniques. It was found that the high catalytic activity and stability of the prepared catalysts could be attributable to high dispersion of reduced Ni species and basicity of support surface. In addition, the effect of feed ratio, nickel loading and GHSV on the catalytic performance of CDRM over the catalysts were investigated. 相似文献
416.
Carbon dioxide (CO2) injection is a well-established method for increasing recovery from oil reservoirs. However, poor sweep efficiency has been reported in many CO2 injection projects due to the high mobility contrast between CO2 and oil and water. Various injection strategies including gravity stable, WAG and SWAG have been suggested and, to some extent, applied in the field to alleviate this problem. An alternative injection strategy is carbonated water injection (CWI). In CWI, CO2 is delivered to a much larger part of the reservoir compared to direct CO2 injection due to a much improved sweep efficiency. In CWI, CO2 is used efficiently and much less CO2 is required compared to conventional CO2 flooding, and hence the process is particularly attractive for reservoirs with limited access to large quantities of CO2 (offshore reservoirs or reservoirs far away from inexpensive natural CO2 resources). This article describes the results of a pore-scale study of the process of CWI by performing high-pressure visualisation flow experiments. The experimental results show that CWI, compared to unadulterated (conventional) water injection, improves oil recovery as both a secondary (before water flooding) and a tertiary (after water flooding) recovery method. The mechanisms of oil recovery by CWI include oil swelling, coalescence of the isolated oil ganglia and flow diversion due to flow restriction in some of the pores as a result of oil swelling and the resultant fluid redistribution. In this article the potential benefit of a subsequent depressurisation period on oil recovery after the CWI period is also investigated. 相似文献
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Ghiassee Mojtaba Rezaei Mehran Meshkani Fereshteh Mobini Sajad 《Research on Chemical Intermediates》2019,45(9):4501-4515
Research on Chemical Intermediates - The MnCo2O4 powders were prepared using a coprecipitation method and employed in low temperature CO oxidation. The preparation parameters in the coprecipitation... 相似文献
419.
Reza Mokhtari 《理论物理通讯》2011,55(2):204-208
The aim of this paper is to generate exact travelling wave solutions of the Harry-Dym equation through the methods of Adomian decomposition, He's variational iteration, direct integration, and power series. We show that the two later methods are more successful than the two former to obtain more solutions of the equation. 相似文献
420.
In this paper, we employ nonpolynomial spline (NPS) basis functions to obtain approximate solutions of the regularized long wave (RLW) equation. By considering suitable relevant parameters, it is shown that the local truncation error behaves O(k 2+h 2) with respect to the time and space discretization. Numerical stability of the method is investigated by using a linearized stability analysis. To illustrate the applicability and efficiency of the aforementioned basis, we compare obtained numerical results with other existing recent methods. Motion of single solitary wave and double and triple solitary waves, wave undulation, generation of solitary waves using the Maxwellian initial condition and conservation properties of mass, energy, and momentum of numerical solutions of the equation are dealt with. 相似文献