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排序方式: 共有168条查询结果,搜索用时 15 毫秒
1.
A. Fernndez-Mateos E.M. Martín de la Nava R. Rabanedo Clemente R. Rubio Gonzlez M.S.J. Simmonds 《Tetrahedron》2005,61(52):12264-12274
A diastereoselective synthesis of the model insect antifeedant 29 a CDE molecular fragment of 12-ketoepoxyazadiradione has been achieved in ten steps from indenone 9 in 44% overall yield. Several of the compounds obtained along the synthesis related to model compound 29 show significant antifeedant activity against Spodoptera littoralis and Spodoptera frugiperda. 相似文献
2.
Virgil Percec Brian C. Auman Hildeberto Nava Joseph P. Kennedy 《Journal of polymer science. Part A, Polymer chemistry》1988,26(3):721-741
Alternating—i.e., -(A-B)n- type—block copolymers of polyisobutylene (PIB) and aromatic polyether sulfone (PSU) have been prepared by phase transfer catalyzed Williamson polyetherification of α,ω-di(phenol)PIB with α,ω-di(chloroallyl)- or -(bromobenzyl)PSU. Block copolymers of the two prepolymers were also synthesized by the phase transfer catalyzed polyetherification of methylene chloride with α,ω-di(phenol)PIB and α,ω-di(phenol)PSU (bisphenol-A-terminated PSU). This method leads to -[(A)x-(B)y]n- block copolymers with formal linkages between segments. At sufficiently high segment lengths, both types of block copolymers exhibit two distinct Tgs, indicating phase separation into rubbery PIB and glassy PSU domains. 相似文献
3.
O Ladrón de Guevara C Cortinas de Nava P Padilla J Espinosa M Cebrian L García 《Journal of chromatography. A》1990,528(1):35-41
For the determination of beta-aminoisobutyric acid (BAIBA) in urine samples in which the beta-alanine concentrations are higher than those of BAIBA, the resolution between these two amino acids, separated by reversed-phase liquid chromatography on an octadecylsilane column, was optimized. The chromatographic analysis included precolumn derivatization of amino acids with o-phthalaldehyde, followed by a 15-min isocratic elution and detection at 340 nm. Because of its simplicity, this method should be useful for monitoring urinary excretion of BAIBA. 相似文献
4.
J. Escribano R. Masegosa D. Nava M. G. Prolongo Catalina Salom 《Journal of Thermal Analysis and Calorimetry》2006,83(3):675-679
The
mineral sabugalite (HAl)0.5[(UO2)2(PO4)]2⋅8H2O, has been studied using a combination of energy
dispersive X-ray analysis, X-ray diffraction, dynamic and controlled rate
thermal analysis techniques. X-ray diffraction shows that the starting material
in the thermal decomposition is sabugalite and the product of the thermal
treatment is a mixture of aluminium and uranyl phosphates. Four mass loss
steps are observed for the dehydration of sabugalite at 48°C (temperature
range 39 to 59°C), 84°C (temperature range 59 to 109°C), 127°C
(temperature range 109 to 165°C) and around 270°C (temperature range
175 to 525°C) with mass losses of 2.8, 6.5, 2.3 and 4.4%, respectively,
making a total mass loss of water of 16.0%. In the CRTA experiment mass loss
stages were found at 60, 97, 140 and 270°C which correspond to four dehydration
steps involving the loss of 2, 6, 6 and 2 moles of water. These mass losses
result in the formation of four phases namely meta(I)sabugalite, meta(II)sabugalite,
meta(III)sabugalite and finally uranyl phosphate and alumina phosphates. The
use of a combination of dynamic and controlled rate thermal analysis techniques
enabled a definitive study of the thermal decomposition of sabugalite. While
the temperature ranges and the mass losses vary due to the different experimental
conditions, the results of the CRTA analysis should be considered as standard
data due to the quasi-equilibrium nature of the thermal decomposition process.
The online version of the original article can be found at 相似文献
5.
V. G. Pleshakov V. M. Akimov E. Huipe Nava S. V. Lindeman Yu. T. Struchkov K. D. Ambacheu A. G. Dudareva M. A. Ryashentseva V. P. Zvolinsky N. S. Prostakov 《Russian Chemical Bulletin》1995,44(4):682-688
Based on thermogravimetric characteristics first obtained for the model 6H-indeno [1,2-b]quinoline, the scheme of thermal conversions of this compound in the temperature range 20–700 °C has been proposed, and the limit of its thermal stability (300 °C) has been determined. This temperature is recommended as the optimum for synthesizing fused benzoaza(diaza)fluorenes. Based on the results of X-ray structural analysis, the molecules of the studied indenoquinoline form centrosymmetric pairs, which are arranged in (110) layers. The molecules are orientationally disordered. The observed self-association of these molecules is similar to the - association of fused heterocyclic systems with-excessive and
****- deficient fragments. It has been suggested that interferon-inducing and antitumor compounds with an annelated indenyl fragment have a common mechanism of action according to the intercalation model of stacking structures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 703–709, April, 1995. 相似文献
6.
7.
G. Pacheco G. Nava P. Bosch S. Bulbulian 《Journal of Radioanalytical and Nuclear Chemistry》1994,187(6):431-434
The ability of synthetic and natural Mexican zeolites and clays to remove radioactive Co from aqueous solutions is discussed. In the various samples, crystallinity was determined by X-ray diffraction. The amount of radionuclide sorbed by the aluminosilicates was determined by -spectrometry. 相似文献
8.
9.
Contreras Ricardo R. Fontal Bernardo Bahsas Alí Suárez Trino Reyes Marisela Bellandi Fernando Nava Flor Cancines Pedro 《Transition Metal Chemistry》2004,29(1):51-55
The synthesis of [benzyl-N,N-alkylbis(2-amino-1-cyclopentencarbodithioate)]MII [alkyl = ethene (L2) and propene, (L3) and M = Cu, Ni and Co] complexes and their characterization (u.v.–vis., FT-IR, 1H-n.m.r., mass spectra and cyclic voltametry) are reported. 相似文献
10.