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71.
Tarik E. Ali 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):88-96
The synthesis of some new 1,3,2-oxazaphosphinine 18, 1,3,2-diazaphosphinine 19, acyclic, and cyclic α-aminophosphonate derivatives 3–17 containing the chromone moiety have been achieved via reaction of 3-(phenyliminomethyl)chromone (1), 3-(phenylaminomethylene)-2-hydroxychromanone (4), and/or 3-(phenylamino-methylene)-2-(phenylamino)chromanone (5) with diethyl phosphite, tris(2-chloroethyl)phosphite, and phenylphosphonic dichloride. Structures of the products were verified on the basis of their elemental analyses, IR, 1H, and 31P NMR spectral data. 相似文献
72.
Mounir A. I. Salem Tarik E. Ali Magda I. Marzouk 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):336-342
Abstract The electron impact induced fragmentation reactions of 3-(4-chlorophenyl)-3,4- dihydro-2-ethoxy-2-oxido-7-methyl-2H,6H-[1,2,4]triazino[4,3-e][1,4,5,2]thiadiazaphosphin in-6-one (1), 3,7-dimethyl-2-ethoxy-2-oxido-1,2,3,4-tetrahydro-6H-[1,2,4]triazino[4,3-b][1,2,4,5]triazaphosphinin-6-one (2), and 9-amino-3,7-dimethyl-4-ethoxy-4-oxido-2,3,4,9-tetrahydro-8H-[1,2,4]triazino[3,2-c][1,2,4,5]triazaphosphinin-8-one (3) are presented and compared. The 1,2,4-triazine rings have almost identical fragmentation routes. The 1,2,4-triazine rings are rather stable relative to the phosphorus rings. Therefore, fragmentation of the phosphorus rings is more favorable for the compounds than the stable 1,2,4-triazine rings. 相似文献
73.
The integration of microactuators within a silicon photonic chip gave rise to the field of optical micro‐electro‐mechanical systems (MEMS) that was originally driven by the telecommunication market. Following the latter's bubble collapse in the beginning of the third millennium, new directions of research with considerable momentum appeared focusing on the realization and applications of miniaturized instrumentation in biology, chemistry, physics and materials science. At the heart of these applications light interferometry is a key optical phenomenon, in which miniaturized scanning interferometers are the manipulating optical devices. Monolithic free‐space optical interferometers realized on a silicon chip take advantage of the recent progress in the microfabrication technology that is enabling accurate control of the etching depth, the aspect ratio, the verticality and the curvature of the etched surfaces. The fabrication technology, the library of micro‐optical and mechanical components, the realized architectures and their characterization are described in detail in this review, followed by a discussion of the foreseen challenges.
74.
Bennani M Badri S Baibai T Oubrim N Hassar M Cohen N Amarouch H 《Applied biochemistry and biotechnology》2011,165(1):290-299
Shiga toxin Escherichia coli (STEC), also called verotoxin-producing E. coli, is a major cause of food-borne illness, capable of causing hemorrhagic colitis and hemolytic–uremic syndrome (HUS). This
study was carried out to evaluate the presence of (STEC) and E. coli O157:H7 in shellfish and Mediterranean coastal environments of Morocco. The contamination of shellfish and marine environment
with Shiga toxin-producing E. coli (STEC) and E. coli O157:H7, was investigated during 2007 and 2008. A total of 619 samples were analyzed and 151 strains of E. coli were isolated. The presence of the stx1, stx2, and eae genes was tested in E. coli isolates strains using a triplex polymerase chain reaction. STEC was detected in three positives samples (1.9%), corresponding
to the serotype O157:H7, the others Shiga toxin-producing E. coli non-O157 were also detected. 相似文献
75.
This paper investigates the existence of absolute optimal solutions for a partition P in continuous and quasiconcave games. We show that the P-consistency property introduced in the paper, together with the quasiconcavity and continuity of payoffs, permits the existence of P-absolute optimal solutions in games with compact and convex strategy spaces. The P-consistency property is a general condition that cannot be dispensed with for the existence of P-absolute optimal solutions. We also characterize the existence of P-absolute optimal solutions by providing necessary and sufficient conditions. Moreover, we suggest an algorithm for efficiently computing P-absolute optimal solutions. 相似文献
76.
Bilge Baytekin Dr. H. Tarik Baytekin Dr. Uwe Hahn Dr. Werner Reckien Dr. Barbara Kirchner Prof. Dr. Christoph A. Schalley Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(29):7139-7149
The mass spectrometric characterization of Fréchet‐type dendrons is reported. In order to provide the charges necessary for electrospray ionization, dendrons bearing an OH group at the focal point can be deprotonated and observed in the negative ion mode. Alternatively, the corresponding bromides can be converted to quaternary ammonium ions that can easily be detected in the positive mode. If the latter ions are subjected to collision‐induced dissociation experiments, a fragmentation cascade begins with the dissociation of the focal amine. The focal benzyl cation quickly decomposes in a fragmentation cascade from the focal point to the periphery until the peripheral benzyl (or naphthylmethyl) cations are formed. Five different mechanisms are discussed in detail, three of which can be excluded based on experimental evidence. The cascade fragmentation is reminiscent of self‐immolative dendrimers. 相似文献
77.
This note presents a contingent-claims approach to strategic capacity planning. We develop models for capacity choice and expansion decisions in a single firm environment where investment is irreversible and demand is uncertain. These models illustrate specifically the relevance of path-dependent options analysis to planning capacity investments when the firm adopts demand tracking or average capacity strategies. It is argued that Asian/average type real options can explain hysteresis phenomena in addition to providing superior control of assets in place. 相似文献
78.
Strain-dependent deformation behavior in nanocrystalline metals 总被引:1,自引:0,他引:1
The deformation behavior as a function of applied strain was studied in a nanostructured Ni-Fe alloy using the in situ synchrotron diffraction technique. It was found that the plastic deformation process consists of two stages, undergoing a transition with applied strain. At low strains, the deformation is mainly accommodated at grain boundaries, while at large strains, the dislocation motion becomes probable and eventually dominates. In addition, current results revealed that, at small grain sizes, the 0.2% offset criterion cannot be used to define the macroscopic yield strength any more. The present study also explained the controversial observations in the literature. 相似文献
79.
80.
Evidence has been found for the presence of an oxazoline ring in a siderophore from Paracoccus denitrificans. This requires revision of the previously assigned structure for this compound. 相似文献