排序方式: 共有117条查询结果,搜索用时 15 毫秒
21.
Numerical Algorithms - Recently, Axelsson and Salkuyeh in (BIT Numerical Mathematics, 59 (2019) 321–342) proposed the transformed matrix iteration (TMIT) method for solving a certain... 相似文献
22.
Abbas Tarassoli Tahereh Sedaghat Hamid-Reza Goudarzi 《Central European Journal of Chemistry》2009,7(1):130-133
Aminolysis of N3P3CI6 by an oxodiamine, bis-(2-ortho-aminophenoxyethyl) ether, has been carried out under various experimental conditions and new
products with different architectures have been obtained. The reaction in diethyl ether when using a Na2CO3-water interface process gives the mono-BINO as major product. Reaction on Al2O3/KOH leads to the spirocyclic compound, while, when the reaction is carried out in toluene in the presence of NEt3, a mixture of mono- and di-BINO products are obtained. These new products have been characterized by IR, 1H and 31P NMR spectroscopy.
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23.
Among photochromic compounds 1,3-diazabicyclo[3.1.0]hex-3-ene derivatives are currently the subject of intense research due to their photochromic behavior particularly in the crystalline state. In this work, the click syntheses of photochromic compounds containing tetrasubstituted imidazole moieties have been investigated. The structure?Cphotochromic behavior relationships of these compounds have been evaluated. 相似文献
24.
Valenti G Rampazzo E Bonacchi S Khajvand T Juris R Montalti M Marcaccio M Paolucci F Prodi L 《Chemical communications (Cambridge, England)》2012,48(35):4187-4189
Colour emission of core-shell silica-PEG nanoparticles in water is tuned with an electrochemically induced energy transfer approach. The lack of solubility problems, side electrochemical reactions involving donors and acceptors within the nanoparticle, and the possibility of using many classes of dyes in ECL applications confirm the validity of this strategy. 相似文献
25.
M. R. Ganjali Tahereh Poursaberi Fatemeh Basiripour Masoud Salavati-Niassari Mohammad Yousefi Mojtaba Shamsipur 《Analytical and bioanalytical chemistry》2001,370(8):1091-1095
A PVC membrane electrode based on a cadmium–salen (N,N′-bis-salicylidene-1,2ethylenediamine) complex as an anion carrier is described. The electrode has an anti-Hofmeister selectivity
sequence with a preference for thiocyanate at pH 1.5–11.0. It has a linear response to thiocyanate from 1.0 × 10–6 to 1.0 × 10–1 mol L–1 with a slope of 59.1 ± 0.2 mV per decade, and a detection limit of 7 × 10–7 mol L–1. This electrode has high selectivity for thiocyanate relative to many common organic and inorganic anions. The proposed sensor
has a fast response time of approximately 15 s. It was applied to the determination of thiocyanate in a milk sample.
Received: 1 December 2000 / Revised: 19 April 2001 / Accepted: 30 April 2001 相似文献
26.
As a consequence of gravitational induced uncertainty, equation of motion for harmonic oscillator differs considerably from
usual quantum mechanical situation. This paper considers the dynamics of a simple harmonic oscillator in the context of Generalized
(Gravitational) Uncertainty Principle (GUP). Using Heisenberg Picture of quantum mechanics, we find time evolution of position
and momentum operators and we will show that expectation values have an unusual complicated mass dependence. Also we will
show that since the notion of locality breaks down, Ehrenfest theorem is not satisfied for harmonic oscillator in GUP. 相似文献
27.
In this report, we try to show the importance of incorporation of name reactions in the sequential cascade reaction in which significantly decreasing the number of steps towards an ideal and practical multi-step synthesis of natural products as well showing virtually all the advantages already mentioned for “Click Chemistry”. In addition, since the chiral inductions are desired for most of these sequential name reactions, their asymmetric catalyzed reactions were also described. 相似文献
28.
Novel sulfate ion-selective polymeric membrane electrode based on a derivative of pyrilium perchlorate 总被引:1,自引:0,他引:1
Ganjali MR Naji L Poursaberi T Taghizadeh M Pirelahi H Yousefi M Yeganeh-Faal A Shamsipur M 《Talanta》2002,58(2):359-366
A sulfate ion-selective PVC membrane sensor based on 4-(4-bromophenyl)-2,6-diphenylpyrilium perchlorate (BDPP) as a novel sensing material is successfully developed. The electrode shows a good selectivity for sulfate ion with respect to common organic and inorganic anions. The sensor exhibits a good linear response with slope of -28.9+/-0.5 mV per decade over the concentration range of 1.0x10(-6)-1.0x10(-2) M, and a detection limit of 8.0x10(-7) M of SO(4)(2-) ions. The electrode response is independent of pH in the range of 4.0-9.0. The proposed sensor was applied as an indicator electrode in potentiometric titration of sulfate and barium ions, and to the determination of zinc in zinc sulfate tablets. 相似文献
29.
An optical chemical sensor based on immobilization of 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol (Br-PADAP) in Nafion membrane is described. The membranes were cast onto glass substrates and were used for the determination of nickel in aqueous solutions by spectrophotometry. The sensor system is highly transparent, mechanically stable and showed no evidence of reagent leaching. The influence of several parameters such as pH, ligand concentration, and type and concentration of regenerating solution were optimized. The sensor system showed good sensitivity in the range 0.5-20 μg ml−1 with a detection limit of 0.3 μg ml−1 Ni(II). The sensor has been incorporated into a home-made flow-through cell for determination of nickel in flowing streams with improved sensitivity, precision and detection limit. The calibration curve in the flow system was linear in the range 0.1-16 μg ml−1 with a detection limit of 0.07 μg ml−1. The sensor is easily regenerated by dilute nitric acid solution. The proposed method was successfully applied to the determination of nickel content in vegetable oil and chocolate samples and the results were compared with those obtained using atomic absorption spectrometry. 相似文献
30.
Abdolali Alizadeh Tahereh Firuzyar Azadeh Mikaeili 《Journal of heterocyclic chemistry》2013,50(3):676-679
An efficient, one‐pot synthetic protocol for polyfunctionalized 1,4‐dihydropyridine‐fused‐1,3‐diazaheterocycles, a class of biologically active compounds, starting from 1,1‐bis(methylthio)‐2‐nitroethylene, 1,n‐diamine, arylaldehyde, and malononitrile is described. The reactions are completed within 12–15 h under refluxing conditions and in the presence of 10 mol % of piperidine as a basic catalyst to produce the title compounds in 60–75% yields. 相似文献