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21.
In this paper a concept of amenability for an arbitrary subset A of discrete semigroup S called A-amenable is introduced and studied. This concept is characterized by several equivalent statements which are analogues of properties characterizing left amenable semigroups. We also obtain the relationship between this version of amenability and Følner’s condition. 相似文献
22.
Moslem Mansour Lakouraj Masoud Mokhtary 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):53-56
Abstract A Mild and efficient method for preparing amides by reaction of nitriles with benzhydrol and tertiary alcohols is described
using polyvinylpolypyrrolidone-supported boron trifluoride. Selective amidation of benzhydrol in the presence of primary benzyl
alcohols was also achieved.
Graphical abstract
相似文献
23.
The dispersion properties of three-dimensional electrostatic waves in a nonuniform electron–positron (EP) magnetoplasma are analyzed. A new dispersion relation is derived by use of the electron and positron density responses arising from the electron and positron continuity and Poisson equations. In the local approximation, the dispersion relation admits two wave modes with different velocities. The growth rates of various modes are illustrated both analytically and numerically. Considering the temperature gradients produces a linearly stable transverse mode. The growth rate of the slow mode instability due to the density inhomogeneity only is the highest one, though it appears at higher thermal energy. The angle of the wave propagation affects drastically on the instability features in each case. The applications of the present analysis are briefly discussed. 相似文献
24.
Sarbast Moslem Danish Farooq Arshad Jamal Yahya Almarhabi Meshal Almoshaogeh Farhan Muhammad Butt Rana Faisal Tufail 《Entropy (Basel, Switzerland)》2022,24(3)
Frequent lane changes cause serious traffic safety concerns, which involve fatalities and serious injuries. This phenomenon is affected by several significant factors related to road safety. The detection and classification of significant factors affecting lane changing could help reduce frequent lane changing risk. The principal objective of this research is to estimate and prioritize the nominated crucial criteria and sub-criteria based on participants’ answers on a designated questionnaire survey. In doing so, this paper constructs a hierarchical lane-change model based on the concept of the analytic hierarchy process (AHP) with two levels of the most concerning attributes. Accordingly, the fuzzy analytic hierarchy process (FAHP) procedure was applied utilizing fuzzy scale to evaluate precisely the most influential factors affecting lane changing, which will decrease uncertainty in the evaluation process. Based on the final measured weights for level 1, FAHP model estimation results revealed that the most influential variable affecting lane-changing is ‘traffic characteristics’. In contrast, compared to other specified factors, ‘light conditions’ was found to be the least critical factor related to driver lane-change maneuvers. For level 2, the FAHP model results showed ‘traffic volume’ as the most critical factor influencing the lane changes operations, followed by ‘speed’. The objectivity of the model was supported by sensitivity analyses that examined a range for weights’ values and those corresponding to alternative values. Based on the evaluated results, stakeholders can determine strategic policy by considering and placing more emphasis on the highlighted risk factors associated with lane changing to improve road safety. In conclusion, the finding provides the usefulness of the fuzzy analytic hierarchy process to review lane-changing risks for road safety. 相似文献
25.
Moslem M. Lakouraj Barahman Movassagh Kyumars Bahrami 《Monatshefte für Chemie / Chemical Monthly》2002,133(9):1193-1196
Summary. Nitrostyrenes are conveniently converted to the corresponding carboxylic acids in high yields at room temperature with Amberlyst
A-26 supported hydroperoxide which is prepared in situ from 35% hydrogen peroxide and amberlyst A-26 (OH−).
Corresponding authors. E-mail: mlakouraj@yahoo.com
Received October 5, 2001. Accepted November 28, 2001 相似文献
26.
Moslem M. Lakouraj Barahman Movassagh Zahra Fadaei 《Monatshefte für Chemie / Chemical Monthly》2002,93(1):1085-1088
Various thiol esters were prepared by condensation of acyl chlorides with disulfides in the presence of Zn/AlCl3. The advantages of this method are high yields under relatively mild conditions, simple work-up, lack of toxicity, and low costs. 相似文献
27.
In this paper, a popular scalarization problem in multiobjective optimization, introduced by Benson, is considered. In the literature it was proved that, under convexity assumption, the set of properly efficient points is empty when the Benson’s problem is unbounded. In this paper, it is shown that this result is still valid in general case without convexity assumption. 相似文献
28.
Mahmood Tajbakhsh Moslem M. Lakouraj Majid S. Mahalli 《Monatshefte für Chemie / Chemical Monthly》2008,10(2):1453-1456
Various symmetrical dialkyl and diacyl disulfides are prepared easily in high yields from the corresponding alkyl and acyl
halides under mild and nonaqueous conditions using N,N′-dibutyl-N,N,N′,N′-tetramethyl-ethylenediammonium tetrahydroborate (BTMETB) or N,N′-dibenzyl-N,N,N′,N′-tetramethylethylenediammonium tetrahydroborate (BZTMETB) and elemental sulfur. The quaternary diammonium borohydrides were easily prepared by treatment of the corresponding quaternary
diammonium chloride or bromide with alkaline solution of sodium borohydride at room temperature. 相似文献
29.
Mahmood Tajbakhsh Moslem M. Lakouraj Majid S. Mahalli 《Monatshefte für Chemie / Chemical Monthly》2008,139(12):1453-1456
Various symmetrical dialkyl and diacyl disulfides are prepared easily in high yields from the corresponding alkyl and acyl
halides under mild and nonaqueous conditions using N,N′-dibutyl-N,N,N′,N′-tetramethyl-ethylenediammonium tetrahydroborate (BTMETB) or N,N′-dibenzyl-N,N,N′,N′-tetramethylethylenediammonium tetrahydroborate (BZTMETB) and elemental sulfur. The quaternary diammonium borohydrides were easily prepared by treatment of the corresponding quaternary
diammonium chloride or bromide with alkaline solution of sodium borohydride at room temperature.
Correspondence: Mahmood Tajbakhsh, Department of Chemistry, Mazandaran University, Babolsar, Iran. 相似文献
30.
Daryoush Afzali Moslem Afzali Maryam Ghanbarian 《International journal of environmental analytical chemistry》2018,98(4):338-348
In the present study, the ?5-(4-dimethylaminobenzylidene)rhodanin-modified SBA-15? was applied as stable solid sorbent for the separation and preconcentration of trace amounts of cobalt ions in aqueous solution. SBA-15 was modified by ?5-(4-dimethylaminobenzylidene)rhodanin reagent. The sorption of Co2+ ions was done onto modified sorbent in the pH range of 6.8–7.9 and desorption occurred in 5.0 mL of 3.0 mol L?1 HNO3. The results exhibit a linear dynamic range from 0.01 to 6.0 mg L?1 for cobalt. Intra-day (repeatability) and inter-day (reproducibility) for 10 replicated determination of 0.06 mg L?1 of cobalt was ±1.82% and ?±1.97%?. Detection limit was 4.2 µg L?1 (3Sb, n = 5) and preconcentration factor was 80. The effects of the experimental parameters, including the sample pH, flow rates of sample and eluent solution, eluent type and interference ions were studied for the preconcentration of Co2+. The proposed method was applied for the determination of cobalt in standard samples, water samples and agricultural products. 相似文献