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31.
Dorota Gryko DanielT. Gryko Hanna Sierzputowska‐Gracz Piotr Piatek Janusz Jurczak 《Helvetica chimica acta》2004,87(1):156-166
The efficient synthesis of eight new macrocyclic amides (lactams) via reaction of diesters with diamines under normal dilution conditions is described. The role of intermolecular H‐bond formation and steric hindrance is discussed based on 1H‐ and 15N‐NMR studies of appropriate model compounds. Principles for the optimal choice of esters that can be efficiently transformed into diamides have been developed. 相似文献
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33.
Electrochemical studies of famotidine were carried out using voltammetric techniques: cyclic voltammetry, linear sweep and square wave adsorptive stripping voltammetry. The dependence of the current on pH, buffer concentration, nature of the buffer, and scan rate was investigated. The best results for the determination of famotidine were obtained in MOPS buffer solution at pH 6.7. This electroanalytical procedure enabled to determine famotidine in the concentration range 1 × 10−9–4 × 10−8 mol L−1 by linear sweep adsorptive stripping voltammetry (LS AdSV) and 5 × 10−10–6 × 10−8 mol L−1 by square wave adsorptive stripping voltammetry (SW AdSV). Repeatability, precision and accuracy of the developed methods were checked. The detection and quantification limits were found to be 1.8 × 10−10 and 6.2 × 10−10 mol L−1 for LS AdSV and 4.9 × 10−11 and 1.6 × 10−10 mol L−1 for SW AdSV, respectively. The method was applied for the determination of famotidine in urine. 相似文献
34.
A finite Heisenberg magnetic ring with an arbitrary single-node spin and two spin deviations from the ferromagnetic saturation
is considered as the system of two Bethe pseudoparticles. The set of all relevant magnetic configurations spans a surface
which can be recognised as a Mőbius strip. The dynamics of the system imposes the double twist of all regular orbits of the
translation symmetry group. 相似文献
35.
JPC – Journal of Planar Chromatography – Modern TLC - A new, simple, accurate, and rapid high-performance thin-layer chromatographic method has been developed for the determination of... 相似文献
36.
A modification of a solution concept of the linear programming problem with interval coefficients in the constraints 总被引:1,自引:0,他引:1
Dorota Kuchta 《Central European Journal of Operations Research》2008,16(3):307-316
We propose a modification of a concept of solving a linear programming problem with interval coefficients in the constraints.
The original concept imposes the decision maker a way comparing intervals, our modification—which is an interactive approach,
comprising the original one as its special case—gives him more freedom in the choice of the preference relation. Thanks to
this flexibility he may be able to find a solution which better suits his needs and attitude towards risk. What is more, our
modification corrects a serious drawback of the original method. 相似文献
37.
Banholzer MJ Li S Ketter JB Rozkiewicz DI Schatz GC Mirkin CA 《The journal of physical chemistry. C, Nanomaterials and interfaces》2008,112(40):15729-15734
We have developed a method to smooth the end sections of nanowires and nanograps generated via the On-Wire Lithography process and studied these rods with optical spectroscopies and theoretical modeling (Discrete Dipole Approximation). The first step of the smoothing process is a reductive one aimed at controlling the diffusion and migration of metal ions to the growing nanorod surface by adjusting the applied potential and concentration of the metal ions in the growth solution. A second oxidative smoothing step, based in part on the energetic differences between topologically rough and smooth surfaces, is used to further smooth the nanorod. The RMS roughness can be reduced over five fold to approximately 5 nm. The properties of these smoothed rods were investigated by empirical and theoretical methods, where it was found the smoothed rods have sharper plasmon resonances and decreased SERS intensity. 相似文献
38.
JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of some antiarrhythmic compounds has been studied on commercially available TLC plates coated with... 相似文献
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40.
Tomasz Manszewski Dorota Prukaa Wiesaw Prukaa Maciej Kubicki 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(10):o493-o495
The crystal structures of the two title (E)‐stilbazolium halogenates, C20H17ClNO+·Cl− and C20H17BrNO+·Br−, are isomorphous, with an isostructurality index of 0.985. The azastyryl fragments are almost planar, with dihedral angles between the benzene and pyridine rings of ca 4.5°. The rings of the benzyl groups are, in turn, almost perpendicular to the azastyryl planes, with dihedral angles larger than 80°. The cations and anions are connected by O—H...X− (X = halogen) hydrogen bonds. The halide anions are `sandwiched' between the charged pyridinium rings of neighbouring molecules, and weak C—H...O hydrogen bonds and C—H...X and C—H...π interactions also contribute to the crystal structures. 相似文献