排序方式: 共有18条查询结果,搜索用时 15 毫秒
1.
Marí a J. Martí n Dragan Vukotic 《Proceedings of the American Mathematical Society》2006,134(6):1701-1705
We show that every composition operator which is an isometry of the Dirichlet space is induced by a univalent full map of the disk into itself that fixes the origin. This is an analogue of the Hardy space result for inner functions due to Nordgren. The proof relies on the Stone-Weierstrass theorem and the Riesz representation theorem.
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Nevenka M. Antovic Perko Vukotic Nikola Svrkota Sergey K. Andrukhovich 《Journal of Radioanalytical and Nuclear Chemistry》2012,293(1):299-302
Plutonium-238 (238Pu) activity concentrations in soil samples from Montenegro (six samples from three localities) have been measured for the first time. The 238Pu/137Cs activity ratio was determined on the basis of alpha and gamma-spectrometric measurements, and found to be with an average of 0.0006 and standard deviation of 0.0003. By using the activity ratios determined in the present study, 238Pu activity concentrations were estimated for three localities in the central: one in the northern, and two in the eastern part of Montenegro. 相似文献
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Three new [2]rotaxanes with aromatic nitrogen donors appended to the crown ether wheel have been synthesized and used as ligands to coordinate Cd(II) ions. One of these yields a new type of 2-periodic, metal organic rotaxane framework in which the wheel rather than the axle is used to link the metal nodes. 相似文献
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Caputo CB Geier SJ Winkelhaus D Mitzel NW Vukotic VN Loeb SJ Stephan DW 《Dalton transactions (Cambridge, England : 2003)》2012,41(7):2131-2139
The lutidine derivative (2,6-Me(2))(4-Bpin)C(5)H(2)N when combined with B(C(6)F(5))(3) yields a frustrated Lewis pair (FLP) which reacts with H(2) to give the salt [(2,6-Me(2))(4-Bpin)C(5)H(2)NH][HB(C(6)F(5))(3)] (1). Similarly 2,2'-(C(5)H(2)(4,6-Me(2))N)(2) and (4,4'-(C(5)H(2)(4,6-Me(2))N)(2) were also combined with B(C(6)F(5))(3) and exposed to H(2) to give [(2,2'-HN(2,6-Me(2))C(5)H(2)C(5)H(2)(4,6-Me(2))N][HB(C(6)F(5))(3)] (2) and [(4,4'-HN(2,6-Me(2))C(5)H(2)C(5)H(2)(2,6-Me(2))N] [HB(C(6)F(5))(3)] (3), respectively. The mono-pyridine-N-oxide 4,4'-N(2,6-Me(2))C(5)H(2)C(5)H(2)(2,6-Me(2))NO formed the adduct (4,4'-N(2,6-Me(2))C(5)H(2)C(5)H(2)(2,6-Me(2))NO)(B(C(6)F(5))(3)) (4) which reacts further with B(C(6)F(5))(3) and H(2) to give [(4,4'-HN(2,6-Me(2))C(5)H(2)C(5)H(2)(2,6-Me(2))NO)B(C(6)F(5))(3)] [HB(C(6)F(5))(3)] (5). In a related sense, 2-amino-6-CF(3)-C(5)H(3)N reacts with B(C(6)F(5))(3) to give (C(5)H(3)(6-CF(3))NH)(2-NH(B(C(6)F(5))(3))) (6). Similarly, the species, 2-amino-quinoline, 8-amino-quinoline and 2-hydroxy-6-methyl-pyridine were reacted with B(C(6)F(5))(3) to give the products as (C(9)H(6)NH)(2-NHB(C(6)F(5))(3)) (7), (C(9)H(6)N)(8-NH(2)B(C(6)F(5))(3)) (8) and (C(5)H(3)(6-Me)NH)(2-OB(C(6)F(5))(3)) (9), respectively; while 2-amino-6-picoline, 2-amino-6-CF(3)-pyridine, 2-amino-quinoline, 8-amino-quinoline and 2-hydroxy-6-methyl-pyridine react with ClB(C(6)F(5))(2) to give the species (C(5)H(3)(6-R)NH)(2-NH(ClB(C(6)F(5))(2))) (R = Me (10), R = CF(3) (11)) (C(9)H(6)NH)(2-NH(ClB(C(6)F(5))(2))) (12), (C(9)H(6)N)(8-NH(2)ClB(C(6)F(5))(2)) (13) and (C(5)H(3)(6-Me)NH)(2-OClB(C(6)F(5))(2)) (14), respectively. In a similar manner, 2-amino-6-picoline and 2-amino-quinoline react with B(C(6)F(5))(2)H to give (C(5)H(3)(6-Me)NH)(2-NH(HB(C(6)F(5))(2))) (15) and (C(9)H(6)NH)(2-NH(HB(C(6)F(5))(2))) (16). The corresponding reaction of 8-amino-quinoline yields (C(9)H(6)N)(8-NHB(C(6)F(5))(2)) (17). In a similar fashion, reaction of 2-amino-6-CF(3)-pyridine resulted in the formation of (18) formulated as (C(5)H(3)(6-CF(3))N)(2-NH(B(C(6)F(5))(2)). Finally, treatment of 15 with iPrMgCl gave (C(9)H(6)N)(2-NH(B(C(6)F(5))(2))) (19). Crystallographic studies of 1, 2, 4, 6, 7, 10, 11, 12 and 15 are reported. 相似文献
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Nahar Singh VN Ojha Nijhuma Kayal Tarushee Ahuja Prabhat K Gupta 《Chemistry Central journal》2011,5(1):17
Arsenic is the toxic element, which creates several problems in human being specially when inhaled through air. So the accurate
and precise measurement of arsenic in suspended particulate matter (SPM) is of prime importance as it gives information about
the level of toxicity in the environment, and preventive measures could be taken in the effective areas. Quality assurance
is equally important in the measurement of arsenic in SPM samples before making any decision. The quality and reliability
of the data of such volatile elements depends upon the measurement of uncertainty of each step involved from sampling to analysis.
The analytical results quantifying uncertainty gives a measure of the confidence level of the concerned laboratory. So the
main objective of this study was to determine arsenic content in SPM samples with uncertainty budget and to find out various
potential sources of uncertainty, which affects the results. Keeping these facts, we have selected seven diverse sites of
Delhi (National Capital of India) for quantification of arsenic content in SPM samples with uncertainty budget following sampling
by HVS to analysis by Atomic Absorption Spectrometer-Hydride Generator (AAS-HG). In the measurement of arsenic in SPM samples
so many steps are involved from sampling to final result and we have considered various potential sources of uncertainties.
The calculation of uncertainty is based on ISO/IEC17025: 2005 document and EURACHEM guideline. It has been found that the
final results mostly depend on the uncertainty in measurement mainly due to repeatability, final volume prepared for analysis,
weighing balance and sampling by HVS. After the analysis of data of seven diverse sites of Delhi, it has been concluded that
during the period from 31st Jan. 2008 to 7th Feb. 2008 the arsenic concentration varies from 1.44 ± 0.25 to 5.58 ± 0.55 ng/m3 with 95% confidence level (k = 2). 相似文献
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A new singly charged pyridinium axle was prepared and combined with disulfonated dibenzo[24]crown-8 ether to form a [2]pseudorotaxane. The reaction of this new, anionic ligand with Zn(II) ions, under various crystallization conditions, resulted in the formation of three metal-organic rotaxane framework (MORF) solids; a one-periodic ML coordination polymer and two, two-periodic ML(2) square grid frameworks. The layers of square grids can be pillared to create full three-periodic MORF structures, which have completely neutral frameworks and are porous. These three-periodic materials represent the first examples of neutral porous MOFs in which one (or more) of the linkers is a mechanically interlocked molecule (MIM). 相似文献
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DS Zhulai SA Bugaychuk GV Klimusheva TA Mirnaya VN Asaula VI Handziuk 《Liquid crystals》2017,44(8):1269-1276
The class of thermotropic ionic liquid crystals (LCs) of the metal alkanoates possesses a number of unique properties, such as intrinsic ionic conductivity, high dissolving ability and ability to form time-stable mesomorphic glasses. These ionic LCs can be used as nanoreactors for the synthesis and stabilisation of different types of nanoparticles (NPs). Thus, some semiconductors, metals and core/shell NPs were chemically synthesised in the thermotropic ionic liquid crystalline phase (smectic A) of the cadmium octanoate (CdC8) and of the cobalt octanoate (CoC8). By applying the scanning electron microscopy, the cadmium and cobalt octanoate composites containing CdS, Au, Ag and core/shell Au/CdS NPs have been studied. NPs’ sizes and dispersion distribution of the NPs’ size in the nanocomposites have been obtained. 相似文献
10.
V. Nicholas Vukotic 《Supramolecular chemistry》2016,28(1-2):151-160
The heterotopic ligand 4,4′-bipyridine-N-monoxide (BIPYMO) has a rigid, linear structure and contains both a pyridine N-donor and a pyridine-N-oxide O-donor which are capable of coordinating to a metal centre or alternatively acting as a hydrogen bond acceptor. The hydrogen bonding capacity of BIPYMO is first demonstrated by the formation of hydrogen-bonded networks with water and some simple dicarboxylic acids (fumaric = FUM, terephthalic = TPA). It is then shown that BIPYMO can coordinate through the pyridine N-donor to Pd(II) and through the pyridine-N-oxide O-donor to Fe(II), Co(II) and Mn(II). In each case, the peripheral, uncoordinated N- or O-atoms act as a hydrogen bond acceptors and interact with a metal-bound and hydrogen bond donor (H2O, fumarate = FUM, malonate = MAL, isophthalate = IPA) to form a solid-state, network through a combination of metal–ligand coordination and hydrogen bonding. Single-crystal X-ray structures of {(BIPYMO)(H2O)2}n, {(BIPYMO)(FUM)}n, {(BIPYMO)(TPA)}n, {[Pd(BIPYMO)2(MAL)2](H2O)}n, {[Pd(BIPYMO)2(IPA)2](H2O)2}n and {[M(BIPYMO)2(FUM)2(H2O)2]}n (M = Mn, Fe, Co), show how the individual building blocks are organised via hydrogen bonding through uncoordinated pyridine N-atoms or pyridine-N-oxide O-atoms to form supramolecular networks. 相似文献