排序方式: 共有77条查询结果,搜索用时 0 毫秒
41.
Let(M,ω)be a symplectic manifold.In this paper,the authors consider the notions of musical(bemolle and diesis)isomorphisms ω~b:T M→T~*M and ω~?:T~*M→TM between tangent and cotangent bundles.The authors prove that the complete lifts of symplectic vector field to tangent and cotangent bundles is ω~b-related.As consequence of analyze of connections between the complete lift ~cω_(T M )of symplectic 2-form ω to tangent bundle and the natural symplectic 2-form dp on cotangent bundle,the authors proved that dp is a pullback o f~cω_(TM)by ω~?.Also,the authors investigate the complete lift ~cφ_T~*_M )of almost complex structure φ to cotangent bundle and prove that it is a transform by ω~?of complete lift~cφ_(T M )to tangent bundle if the triple(M,ω,φ)is an almost holomorphic A-manifold.The transform of complete lifts of vector-valued 2-form is also studied. 相似文献
42.
Manouchehr Mamaghani Abed Badrian 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):1181-1186
The hydroxy group of the Baylis-Hillman adducts was protected with trimethylsilyl (TMS) group using the reaction of adducts 1a–h with hexamethyldisilazane (HMDS) catalyzed by iodine under nearly neutral reaction conditions. 相似文献
43.
Manouchehr Mamaghani Khalil Tabatabaeian Abed Badrian 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1347-1353
A new, universal, and versatile method has been developed for the synthesis of the chiral α,β-unsaturated N-acyl-oxazolidin-2-ones 4 based on the Wittig reaction of the triphenylphosphonium salt 7 derived from the (R)-3-(2-Chloro-acetyl)-5,5-dimethyl-4-phenyl-oxazolidin-2-one 6. 相似文献
44.
Linear-dendritic copolymers containing hyperbranched poly(citric acid) and linear poly(ethylene glycol) blocks (PCA-PEG-PCA) were used as reducing and capping agents to synthesize and support gold nanoparticles (AuNPs). PCA-PEG-PCA copolymers with 1758, 1889 and 3446 molecular weights, called A1, A2 and A3 through this work, respectively, were synthesized using 2, 5, and 10 citric acid/PEG molar ratios. The diameter of A1, A2 and A3 in a fresh water solution was investigated using dynamic light scattering (DLS) and it was between 1.8 and 2.8 nm. AuNPs were simply synthesized and supported by addition a boiling aqueous solution of HAuCl4 to aqueous solutions of A1, A2 and A3. Supported AuNPs were stable in water for several months and agglomeration was not occurred. The loading capacity of A1, A2 and A3 and the size of synthesized AuNPs were investigated using UV spectroscopy and transmission electron microscopy (TEM). It was found that the loading capacity of PCA-PEG-PCA copolymers depend on the concentration of copolymers and the size of their poly(citric acid) parts directly. For example average loading capacities for 400 μM concentration of A1, A2 and A3 were 32.24, 37.4 and 41.52 μM, respectively, and average loading capacities for 400, 200 and 100 μM concentration of A1 were 32.24, 20.28 and 9.1 μM, respectively. Interestingly there was a reverse relation between the size of synthesized AuNPs and size of poly(citric acid) parts of PCA-PEG-PCA copolymers. 相似文献
45.
46.
47.
Manouchehr Saljoughian 《Monatshefte für Chemie / Chemical Monthly》1984,115(4):519-521
Purified partially mono-deuteriatedTMS was synthesized by preparing lithiomethyltrimethylsilane from chloromethyltrimethylsilane and reaction of the former with deuteriated water. Using this reference deuterium chemical shifts in parts per million can be reported with respect to [2H] resonance frequency of internalTMS in deuterium nmr spectroscopy.
Eine einfache zweistufige Synthese von monodeuteriertem Tetramethylsilan (Kurze Mitteilung)
Zusammenfassung Es wird die Synthese von partiell monodeuteriertemTMS beschrieben. Dazu wurde Monochlormethyltrimethylsilan in Lithiomethyltrimethylsilan übergeführt und dieses mit D2O weiter zum Zielprodukt umgesetzt.相似文献
48.
The nanocrystalline cubic, tetragonal, and submicron monoclinic phases of pure zirconia were prepared by thermal decomposition of carbonate and hydroxide precursors. The crystallization and isothermal phase transformations of the oxide were studied using high temperature X‐ray diffraction, X‐ray diffraction and Raman spectra of quenched samples. Cubic zirconia formed first, and then progressively transformed to tetragonal and monoclinic phases at temperatures as low as 320°C. The cubic, tetragonal, and monoclinic phases for ZrO2 were found to be distinct functions of crystallite size, indicating the nanocrystalline nature of these phases. They were found to exist within critical size ranges of 50 to 140 Å, 100 to 220 Å and 190 to 420 Å (±5 Å), respectively. Thus, as the crystallites grow during annealing, they first transform from cubic to tetragonal and then from tetragonal to monoclinic at critical sizes. The classical Avrami equation for nucleation and growth was applied to the tetragonal to monoclinic phase transition. 相似文献
49.
50.
Dr. Cecilia C. Russell Dr. Andrew Stevens Kelly A. Young Jennifer R. Baker Siobhann N. McCluskey Dr. Manouchehr Khazandi Hongfei Pi Dr. Abiodun Ogunniyi Dr. Stephen W. Page Prof. Darren J. Trott Prof. Adam McCluskey 《ChemistryOpen》2019,8(7):896-907
Robenidine (E)-N′-((E)-1-(4-chlorophenyl)ethylidene)-2-(1-(4-chlorophenyl)ethylidene)hydrazine-1-carboximidhydrazide displays methicillin-resistant Staphyoccoccus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) MICs of 2 μg mL−1. Herein we describe the structure-activity relationship development of a novel series of guanidine to 2-aminopyrimidine isosteres that ameliorate the low levels of mammalian cytotoxicity in the lead compound while retaining good antibiotic activity. Removal of the 2-NH2 pyrimidine moiety renders these analogues inactive. Introduction of a central 2-NH2 triazine moiety saw a 10-fold activity reduction. Phenyl to cyclohexyl isosteres were inactive. The 4-BrPh and 4-CH3Ph with MIC values of 2 and 4 μg mL−1, against MRSA and VRE respectively, are promising candidates for future development. 相似文献