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排序方式: 共有410条查询结果,搜索用时 46 毫秒
1.
Andrea Santagati Agostino Marrazzo Giuseppe Granata 《Journal of heterocyclic chemistry》2003,40(5):869-873
Derivatives containing the thieno[2,3‐d]pyrimidin‐4‐one system, potential selective COX‐2 inhibitors, were prepared starting from ethyl ester of 2‐isothiocyanato‐5‐phenyl‐3‐thiophenecarboxylic acid ( 2 ); their structural elucidation is also reported. 相似文献
2.
B. R. Sant 《Fresenius' Journal of Analytical Chemistry》1955,145(4):257-260
Summary The oxidation of hydroxylamine by alkaline ferricyanide has been studied. It is observed that in presence of sodium hydroxide the molar ratio of NH2OH to K3Fe(CN)6 varies between 11.3 to 11.6. Quantitative oxidation to N2 is therefore carried out in weakly alkaline medium using borax-boric acid buffer. Hydroxylamine is estimated by titrating the ferrocyanide formed with standard ceric sulphate. Accurate and reproducible results are obtained if too large an excess of ferricyanide is avoided. Application of the present procedure to the determination of oximes and their metal complexes is suggested.Grateful thanks of the author are due to Prof. S. S. Joshi for facilities and encouragement and to Dr. G. S. Deshmukh for kind interest in the work. 相似文献
3.
Suseela B. Sant 《Fresenius' Journal of Analytical Chemistry》1959,168(2):112-115
Summary Potentiometric titrations of potassium ferricyanide with hydrazine sulfate and arsenic(III) are shown to be feasible at room temperature (25–30° C) and in an optimum alkali concentration of about 2 N when carried out in the initial presence of a few drops of osmic acid as catalyst. The method which is simple, rapid and accurate can be used in the estimation of hydrazine, arsenic(III) or ferricyanide.This work constituted, in part, the author's Ph. D. thesis (1956) at the Banaras Hindu University (India). 相似文献
4.
In this paper we study ω-distributive modules, where ω is a cardinal number. We extend a characterization of distributive modules to ω-distributive modules. In particular, the case in which ω = n is a finite cardinal is considered. We apply the results to the case n = 2, obtaining new characterizations for distributive modules and rings. Special attention is given to saturated submodules and ideals. 相似文献
5.
Cusano A Iadicicco A Pilla P Contessa L Campopiano S Cutolo A Giordano M 《Optics letters》2005,30(19):2536-2538
We theoretically and experimentally investigated the reorganization of cladding modes in high-refractive-index- (HRI-) coated long-period gratings (LPGs), focusing on the influence of refractive-index sensitivity. When azimuthally symmetric nanoscale HRI coatings are deposited along LPG devices, a significant modification of the distribution of cladding modes occurs, depending on the layers' features (refractive index and thickness) and on the external refractive index. In particular, if these parameters are properly chosen, a transition between cladding modes and overlay modes occurs. Numerical and experimental effects of the mode transition on the sensitivity of the surrounding refractive index are described. 相似文献
6.
7.
S. Yu. Kun U. Abbondanno M. Bruno N. Cindro M. D’Agostino P. M. Milazzo R. A. Ricci T. Ritz B. A. Robson W. Scheid A. V. Vagov G. Vannini L. Vannucci 《Zeitschrift für Physik A Hadrons and Nuclei》1997,359(2):145-148
Structures of non-statistical character, recently observed in 58 Ni +46 Ti elastic and 58 Ni +62 Ni elastic and inelastic excitation functions, produce damped oscillations in the cross section energy autocorrelation functions. The analysis of these damped oscillations in terms of S-matrix spin and parity decoherence indicates, as a possible interpretation, damping of the coherent rotational motion of the intermediate dinuclear system formed in the reaction. 相似文献
8.
Link JM Reyes M Yager PM Anjos JC Bediaga I Göbel C Magnin J Massafferi A de Miranda JM Pepe IM dos Reis AC Carrillo S Casimiro E Cuautle E Sánchez-Hernández A Uribe C Vazquez F Agostino L Cinquini L Cumalat JP O'Reilly B Ramirez JE Segoni I Butler JN Cheung HW Gaines I Garbincius PH Garren LA Gottschalk E Kasper PH Kreymer AE Kutschke R Bianco S Fabbri FL Zallo A Cawlfield C Kim DY Rahimi A Wiss J Gardner R Kryemadhi A Chung YS Kang JS Ko BR Kwak JW Lee KB Park H Alimonti G Boschini M 《Physical review letters》2002,88(16):161801
A high statistics measurement of the Lambda(+)(c) lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis technique with particular attention to the determination of the systematic uncertainty. The measured value of 204.6 +/- 3.4 (stat) +/- 2.5 (syst) fs from 8034 +/- 122 Lambda(+)(c)-->pK(-)pi(+) decays represents a significant improvement over the present world average. 相似文献
9.
A. Politano R.G. Agostino E. Colavita V. Formoso G. Chiarello 《Journal of Electron Spectroscopy and Related Phenomena》2008
High-resolution electron energy loss spectroscopy was used to study the electronic properties of (3/2 × 3/2)-Na/Cu(1 1 1) at room temperature. Loss spectra showed two-well distinct losses at 114 and 180 meV assigned to not dispersive charge density waves. Mechanisms to explain their existence are proposed. Moreover, the expected 2D plasmon of the Na quantum well state was not observed. The strong influence of the underlying Cu substrate may be responsible for the absence of such mode. 相似文献
10.
Surface plasmon dispersion in nanoscale thin Ag films deposited onto the Ni(111) surface was investigated by angle‐resolved electron energy loss spectroscopy. We found that the dispersion curve contains only the quadratic term. The vanishing of the linear term was ascribed to the presence in the film of Ag 5sp‐related quantum well states. Screening effects enhanced by electron confinement in Ag quantum well states push the position of the centroid of the induced charge of the surface plasmon less inside the interface compared to other Ag systems, rendering null the linear coefficient of the dispersion curve. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献