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81.
Babak Kaboudin Foad Kazemi Abolfazl Ghaderian Zahra Zand 《Journal of the Iranian Chemical Society》2014,11(4):1121-1127
82.
83.
Let G be a group. If every nontrivial subgroup of G has a proper supplement, then G is called an aS-group. We study some properties of aS-groups. For instance, it is shown that a nilpotent group G is an aS-group if and only if G is a subdirect product of cyclic groups of prime orders. We prove that if G is an aS-group which satisfies the descending chain condition on subgroups, then G is finite. Among other results, we characterize all abelian groups for which every nontrivial quotient group is an aS-group. Finally, it is shown that if G is an aS-group and |G| ≠ pq, p, where p and q are primes, then G has a triple factorization. 相似文献
84.
Yan J Garzan A Narayan RS Vasileiou C Borhan B 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(46):13749-13756
In an attempt to revise the structural assignment of mucoxin, and faced with 64 diastereomeric possibilities, we resorted to the synthesis of truncated structures that contained the core stereochemical sites. Twelve stereochemical analogues were synthesized, their (1)H and (13)C NMR spectra were analyzed and four recurring stereochemical trends were distilled from the data. Applying the observed trends to the diastereomeric population pared the possible choices for the correct structure of mucoxin from 64 to 4. Synthesis of these analogues led to the identification of the correct structure of mucoxin. 相似文献
85.
[reaction: see text] A new concept of simultaneous covalent anchoring of a N-heterocyclic carbene palladium/ionic liquid matrix on the silica surface and the application of the resulting catalyst in the Heck reaction of a variety of different haloarenes is described. The catalyst shows high thermal stability (up to 280 degrees C) and could be recovered and reused for four reaction cycles, giving a total TON congruent with 36 600. Furthermore, TEM coupled with EDX analysis indicate the formation of Pd nanoparticles within the immobilized IL layer. 相似文献
86.
A simple, efficient, and general method has been developed for the one-pot synthesis of α-aminophosphonic esters in water using β-cyclodextrin as an efficient catalyst. α-Aminophosphonic esters were obtained in good yields (45-82%) and purity under mild conditions by the reaction of diethyl phosphite with a mixture of aldehyde and amine in water at reflux. 相似文献
87.
Various types of aromatic and aliphatic sulfides are selectively oxidized to sulfoxides and sulfones in good to excellent yields using 30% H2O2 in the presence of catalytic amounts of a novel recoverable silica-based tungstate interphase catalyst at room temperature. The catalyst can be recovered and reused for at least eight reaction cycles under the described reaction conditions without considerable loss of reactivity. [reaction: see text] 相似文献
88.
Picálek J Minofar B Kolafa J Jungwirth P 《Physical chemistry chemical physics : PCCP》2008,10(37):5765-5775
We performed a detailed molecular dynamics study of the interfacial structure of aqueous solutions of 1-butyl-3-methylimidazolium tetrafluoroborate in order to explain the anomalous dependence of the surface tension on concentration. At low concentrations the surface tension decreases with concentration. At higher concentrations the surface becomes saturated; a plateau is observed in simulations with a non-polarizable force field while a possible increase is detected in simulations with a polarizable force field. The structure is characterized by a surplus of cations at the surface (with hydrophobic butyl chains pointing toward vacuum) which at low concentrations is only partly compensated by the anions because of asymmetric solvation. A more hydrophobic 1-butyl-3-methylimidazolium hexafluorophosphate is also simulated for comparison. 相似文献
89.
Babak Kaboudin Khavar Moradi Elham Safaei Hossein Dehghan Peyman Salehi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):1521-1527
Abstract A proline-based aminophosphinic acid ligand and it's vanadium complex have been synthesized and characterized by spectroscopic techniques. The inhibitory activity on pancreatic α-amylase and Baker's yeast α-glucosidase has been examined in vitro. The novel complex showed more inhibitory potency against pancreatic α-amylase and Baker's yeast α-glucosidase compared to acarbose as an antidiabetic drug. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
90.
A theory of defect-strain instability with formation of periodic surface relief in semiconductors irradiated by ultra-short
(τp=10-13 s) powerful laser pulses is developed. The period and time of formation of surface relief are calculated. Regimes of multi-pulse
laser ablation leading to formation of either a smooth surface or arrays of surface-relief spikes are pointed out and corresponding
experimental results are interpreted from the viewpoint of the developed theory.
Received: 4 December 2000 / Accepted: 23 July 2001 / Published online: 11 February 2002 相似文献