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981.
Two different skeletons of heterocyclic compounds,quinoline and quinazolinone analogs could be obtained by a novel one-pot synthesis from substituted 3-amino-1 H-benzo[f]chromene-2-carbonitrile derivatives and cyclohexanone in DMF in the catalyst of anhydrous zinc chloride under reflux.A plausible mechanism was proposed.  相似文献   
982.
The Cu/SiO2 catalyst prepared by incipient wetness method exhibited very high activity and selectivity for the vapor-phase synthesis of JV-butylaniline from aniline and 1-butanol. When Cu loading was 0.70 mmol/g-SiO2 and the catalyst precursor was calcined at 500 ℃, 1-butanol conversion reached 99%, and the selectivity of JV-butylaniline exceeded 97%.  相似文献   
983.
Gold nanoparticles functionalized with self-assembled films of ferrocenylhexanethiol and mercaptoundecanoic acid (MUA) were used for the determination of ascorbic acid (AA). The modified nanoparticles (mNPs) were prepared by a combination of the modified Schifrin’s and the place-exchange methods. Well-organized films were obtained due to electrostatic attraction between the carboxy groups of MUA and cationic surface of poly(diallyldimethylammonium chloride). The mNP films are highly stable and can be exploited to fabricate an enzyme-less sensor for AA whose function is based on the highly electrocatalytic activity of ferrocene in the mNPs towards AA. The sensor was characterized by cyclic voltammetry and chronoamperometry. Under optimal conditions, the response current towards AA is proportional to its concentration in the range from 8.0 μM to 6.0 mM, with a detection limit of 0.14 μM (at a signal-to-noise ratio of 3). This work represents a simple controlled test-bed for fundamental studies on the use of self-assembled mNPs for sensor applications.  相似文献   
984.
Three different nitrocellulose (NC) samples produced from linters were investigated. DSC studies on the NC+sym-diethyldiphenylurea (C1) mixtures were carried out. The influence of storage time on their pore structures was examined using thermoporometry. The results led to conclusion that large pores are multiples of small ones. The parameter n was used to characterize the number of C1 molecules equivalent to NC ring. Its value for short storage time was about 9 but for longer time reached the value of 3. The influence of thermal history on the phase transition and porosity of the different nitrocellulose samples was different.  相似文献   
985.
以1,3-丁二烯为代表的共轭二烯烃是重要的有机合成原料,在有机合成领域有重要的应用价值.综述了以1,3-丁二烯等为代表的共轭二烯烃定向加成的研究进展,并展望了其发展和应用前景.  相似文献   
986.
987.
We investigate the statistics of polymer capture by a nanopore using Brownian dynamics simulations. It is found that when the velocity flux is greater than a critical velocity flux, the capture picture is a random selection process, otherwise it tends to a statistical process governed by energetic considerations. In addition, the chain ends capture probability decreases as the chain length increases and satisfies a power-law scaling of P0(N)~N-0.8.  相似文献   
988.
N-Substituted benzo[d]isothiazol-3(2H)-ones are a family of compounds with extremely important application. Recently, we have developed a new green pathway to synthesize these compounds via potassium bromide-catalyzed intramolecular oxidative dehydrogenative cyclization. This reaction has high functional group tolerance and affords excellent yield even in gram scale.  相似文献   
989.
Phosphonylation of the pretreated 2-(hydroxymethyl)phenol derivatives with acetic anhydride using trialkylphosphites as the nucleophilic reagents was reported, providing a practical way to the synthesis of novel highly steric 3,3′-bis-substituted benzo[d][1,2]oxaphosphole 2-oxides.  相似文献   
990.
Journal of Radioanalytical and Nuclear Chemistry - Na, Mg, Al and Cl in Roman glasses and pottery were analyzed by PIGE with 2.5 MeV protons and 2.0 MeV deuteron activation...  相似文献   
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