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111.
In this paper, we introduce a strong property (A) as follows: A ring R is called satisfying strong property (A) if every finitely generated ideal of R which is generated by a finite number of zero-divisors elements of R, has a non zero annihilator. We study the transfer of property (A) and strong property (A) in trivial ring extensions and amalgamated duplication of a ring along an ideal. We also exhibit a class of rings which satisfy property (A) and do not satisfy strong property (A). 相似文献
112.
Abdolraouf Samadi-Maybodi Seyed Karim Hassani Nejad-Darzi 《Journal of the Iranian Chemical Society》2012,9(4):431-439
Zinc phosphate molecular sieves were synthesized using zinc chloride, phosphoric acid and (2-hydroxyethyl) trimethylammonium hydroxide as template, respectively. Synthesized samples were characterized by XRD, SEM and FT-IR techniques. The morphology and crystal size of the samples were investigated using ultrasonic during aging process. Large particle size (7.2?×?20.4???m) was obtained by ultrasonication. Imperfect orthorhombic particles were obtained when the sample was mixed with magnetic stirrer; meanwhile, some rod-like particles were obtained when the mixture was stirred with ultrasonic. In addition, the rod-like ??-Zn3(PO4)2·4H2O phase was prepared using ethylene glycol as co-solvent. 相似文献
113.
In this Letter, we demonstrate experimentally that a patchwork of four metal-insulator-metal patches leads to an unpolarized wideband omnidirectional infrared absorption. Our structure absorbs 70% of the incident light on a 2.5 μm bandwidth at 8.5 μm. It paves the way to the design of wideband efficient plasmonic absorbers in the infrared spectrum. 相似文献
114.
Chea A Hout S Long C Marcourt L Faure R Azas N Elias R 《Chemical & pharmaceutical bulletin》2006,54(10):1437-1439
Two new sesquiterpene lactones, vernolides C and D as well as six known ones were isolated from the dichloromethane fraction of an aqueous extract from Vernonia cinerea. Their structures were elucidated by spectroscopic methods. Among the known sesquiterpene lactones, three of them were described in this plant for the first time. In vitro antiplasmodial evaluation showed that the three major compounds 1, 7 and 8 were active against chloroquine resistant Plasmodium falciparum strain (W2) with IC(50) 3.9, 3.7 and 3.5 microM, respectively. 相似文献
115.
Yasser M.Z. Ahmed Mohamed I. Riad Ahmed I. Zaky Mohammed Abdel-Aziz Mohamed M.H. Shalabi 《中国颗粒学报》2007,5(6):391-394
In line with recent attention on porous metals having low and medium porosities in the range of 20-50%, this paper studies the effect of porosity on the mechanical properties of sintered copper compacts. Experiments were designed to investigate the effect of porosity, applied stress and sliding velocity on the wear rate of copper compacts, leading to the finding that the effects of both porosity and applied stress of the wear test on the wear rate are approximately similar and higher than that of sliding velocity. The investigation concerning the effect of porosity on compressive strength indicated that the stress-strain curve of high-porosity compact exhibited identifiable ultimate strength points, though low-porosity compact showed distinct stages of elastic plastic behavior. 相似文献
116.
Fatemeh Sabermahani Mohammad Ali Taher Habibe Bahrami Zahra Hassani 《International journal of environmental analytical chemistry》2013,93(3):265-278
A column, solid phase extraction (SPE), preconcentration method was developed for determination of silver by using alumina coated with 1-((5-nitrofuran-2-yl)methylene)thiosemicarbazide and determination by flame atomic absorption spectrometry. The separation/preconcentration conditions for the quantitative recovery were investigated. At pH 2, the maximum sorption capacity of Ag+ was 7.5?mg?g?1. The linearity was maintained in the concentration range of 0.02–11.0?µg?mL?1 in the final solution or 0.14–1.10?×?104?ng?mL?1 in the original solution for silver. The preconcentration factor of 140 and relative standard deviation of ±1.4% was obtained, under optimum conditions. The limit of detection (LOD) was calculated as 0.112?ng?mL?1, based on 3σbl/m (n?=?8) in the original solutions. The proposed method was successfully applied to the determination trace amounts of silver in the environmental samples such as tea, rice and wheat flour, mint, and real water samples. 相似文献
117.
In the present paper, a numerical model of a fin-and-tube heat exchanger is proposed. The simulation of water vapor condensation
in presence of non-condensable gas (air) between two vertical plane plates and in a plate fin-and-tube heat exchanger in a
stationary mode is performed using Fluent software. The differential equations that describe the heat and mass transfer were
integrated by the finite volume method, in two and three dimensions. 相似文献
118.
A series of triazene derivatives with polyfunctional substituents, such as the ylide moiety and ester groups, were synthesized
by the reaction of dimethyl acetylenedicarboxylate with 1,3-diaryl-1-triazenes in the presence of triphenylphosphine in ethyl
acetate.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 512–514, March, 2007. 相似文献
119.
Jeffery L. Kennington Riad A.K. Mohamed 《Computational Optimization and Applications》1997,8(1):57-71
Most of the preassigned pivot agenda algorithms that extend the Hellerman-Rarick P3 algorithm assume that the input matrix is nonsingular. Due to numerical instability, this assumption may be violated and these algorithms fail. We present a modification of theP3 algorithm which includes a procedure to recover from this type of numerical instability.The recovery procedure is integrated into P3 in such a way that all previous work can be maintained and it reduces the likelihoodthat additional recovery will be required. 相似文献
120.
El Bouzidi L Abbad A Fattarsi K Hassani L Leach D Markouk M Legendre L Bekkouche K 《Natural product communications》2011,6(10):1491-1494
The chemical composition and anticandidal properties of the essential oil of Moroccan Cotula cinerea aerial parts have been examined. GC-MS data were used to identify 24 constituents. Oxygenated monoterpenes constituted the main fraction with trans-thujone (41.4%), cis-verbenyl acetate (24.7%), 1,8-cineole (8.2%) and camphor (5.5%) as the major components. The anticandidal activity of the essential oil was evaluated using a panel of human pathogenic fungi (Candida albicans CCMM L4 and CCMM L5, C. krusei CCMM L10, C. glabrata CCMM L7 and C. parapsilosis CCMM L18). The oil showed high anticandidal activity against all investigated strains with minimal inhibitory concentrations of 3.2 to 4.7 mg/mL depending on the tested yeast and 5.9 mg/mL as a minimal candidicidal concentration value. These findings add significant information to the pharmacological activity of Cotula cinerea essential oil, which may present a good alternative to antibiotics for the treatment of resistant strains of Candida. 相似文献