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排序方式: 共有85条查询结果,搜索用时 15 毫秒
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Collette C Dehareng D De Pauw E Dive G 《Journal of the American Society for Mass Spectrometry》2001,12(3):304-316
The host-guest interactions play a very important role in chemical and biological processes. It is therefore important to be able to characterize these complexes. Electrospray mass spectrometry can be used to characterize the complex formation. It provides information on the mass and the charge of these ionic complexes. In this article, we show that the use of ab initio and semiempirical calculations, in addition to the results obtained by electrospray mass spectrometry, reveal to be a promising tool for the study of these noncovalent complexes. In this article, host-guest complexes formed by macropolycyclic polyammonium host molecules and dicarboxylic acids are studied. 相似文献
3.
J. W. Collette D. M. Gale M. G. Belletete 《Journal of polymer science. Part A, Polymer chemistry》1980,18(3):1071-1078
A wide compositional range of copolymers of 1-cyclobutene carbonitrile (CBCN) and 1-bicyclobutance carbonitrile (BBCN) with common vinyl monomers was prepared in order to study systematically the effect of cyclobutane carbonitrile ring incorporation on the glass transition temperature (Tg). In general, the Tg's of the copolymers are increased in proportion to the weight percent of the small-ring monomer incorporated, but the 1,2-mode of incorporation raises Tg more than the 1,3-mode. Attempts were made to correlate data with quantitative Tg–composition relationships (Fox–Johnston equations). Prediction for nitrile homopolymer Tg's are compared with literature values. 相似文献
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In this paper,we study the surface instability of a cylindrical pore in the absence of stress. This instability is called the Rayleigh-Plateau instabilty. We consider the model developed by Spencer et ... 相似文献
5.
Ebraheem Abdu Musad Saleh Abdullah Mohammed AL Dawsari Kakul Husain Ismail Hassan Kutty K.M.Lokanatha Rai 《Molecules (Basel, Switzerland)》2021,26(2)
A novel synthesis of thiazolo[2,3-b]quinazolines 4(a–e), pyrido[2′,3′:4,5]thiazolo[2,3-b]quinazolines {5(a–e), 6(a–e), and 7(a–e)}, pyrano[2′,3′:4,5]thiazolo[2,3-b]quinazolines 8(a–e), and benzo[4,5]thiazolo[2,3-b]quinazoloine9(a–e) derivatives starting from 2-(Bis-methylsulfanyl-methylene)-5,5-dimethyl-cyclohexane-1,3-dione 2 as efficient α,α dioxoketen dithioacetal is reported and the synthetic approaches of these types of compounds will provide an innovative molecular framework to the designing of new active heterocyclic compounds. In our study, we also present optimization of the synthetic method along with a biological evaluation of these newly synthesized compounds as antioxidants and antibacterial agents against the bacterial strains, like S. aureus, E. coli, and P. aeruginosa. Among all the evaluated compounds, it was found that some showed significant antioxidant activity at 10 μg/mL while the others exhibited better antibacterial activity at 100 μg/mL. The results of this study showed that compound 6(c) possessed remarkable antibacterial activity, whereas compound 9(c) exhibited the highest efficacy as an antioxidant. The structures of the new synthetic compounds were elucidated by elemental analysis, IR, 1H-NMR, and 13C-NMR. 相似文献
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Gomez L Slutzky C Ferron J de La Figuera J Camarero J Vazquez De Parga AL de Miguel JJ Miranda R 《Physical review letters》2000,84(19):4397-4400
Generic computer simulations using empiric interatomic potentials suggest a new, collective mechanism that could be responsible for mixing at heteroepitaxial interfaces. Even if single adsorbate atoms diffuse by hopping on the substrate surface and do not mix at the terraces, two-dimensional islands formed by nucleation may become unstable above a certain critical size and explode upwards forming clusters of several atomic layers. This process is accompanied by strong distortions of the underlying atomic layers, and on soft materials it can result in surface etching and incorporation of substrate atoms into the islands. 相似文献
7.
Floraine Collette Régis Delatouche Christophe Blanquart Fabien Gueugnon Marc Grégoire Philippe Bertrand Valérie Héroguez 《Journal of polymer science. Part A, Polymer chemistry》2013,51(1):176-189
In this contribution, a versatile approach for the synthesis of functionalized particles for drug delivery is presented, using two nonaggressive standardized procedures. The first procedure considered is the functionalization of an azido‐terminated α‐norbornenyl poly(ethylene oxide) (PEO) macromonomer with an alkyne‐containing active molecule via the copper catalyzed azide alkyne cycloaddition, click type reaction. The functionalized macromonomer is then polymerized by Ring‐Opening Metathesis Polymerization (ROMP) in dispersion to form functionalized particles. The second procedure consists in synthesizing particles by ROMP in dispersed media of norbornene with azido‐terminated α‐norbornenyl PEO macromonomer. The ROMP was initiated by the first generation Grubbs catalyst. Such functionalized core‐shell particles have stealthy properties due to their PEO shell and can be viewed as universal nanocarriers on which any alkyne‐modified active molecule can be grafted by click chemistry. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
8.
A family of proximity graphs, called Empty Region Graphs (ERG) is presented. The vertices of an ERG are points in the plane, and two points are connected if their neighborhood, defined by a region, does not contain any other point. The region defining the neighborhood of two points is a parameter of the graph. This way of defining graphs is not new, and ERGs include several known proximity graphs such as Nearest Neighbor Graphs, β-Skeletons or Θ-Graphs. The main contribution is to provide insight and connections between the definition of ERG and the properties of the corresponding graphs.We give conditions on the region defining an ERG to ensure a number of properties that might be desirable in applications, such as planarity, connectivity, triangle-freeness, cycle-freeness, bipartiteness and bounded degree. These conditions take the form of what we call tight regions: maximal or minimal regions that a region must contain or be contained in to make the graph satisfy a given property. We show that every monotone property has at least one corresponding tight region; we discuss possibilities and limitations of this general model for constructing a graph from a point set. 相似文献
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