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71.
Zhang S Majewski PW Keskar G Pfefferle LD Osuji CO 《Langmuir : the ACS journal of surfaces and colloids》2011,27(18):11616-11621
Lyotropic nanowire dispersions are attractive precursors for semiconductor device fabrication because they permit the alignment control of active nanomaterials. The reliable production of nanowire-based mesophases, however, is very challenging in practice. We show that appropriately functionalized high-aspect-ratio nanowires of single-crystal ZnO spontaneously form nematic phases in organic and aqueous media. These systems show isotropic, biphasic, and nematic phases on increasing concentration, in reasonable agreement with Onsager's theory for rigid rods interacting via excluded volume. Suspensions were readily processed to produce films with large-area monodomains of aligned nanowires. Imprints of the director field in quiescently dried films display a propensity for bend deformation in the organic mesophase versus splay deformation in the aqueous case, suggesting that system elasticity may be tuned via surface functionalization. These results provide critical insight for the utilization of semiconductor nanowires as novel mesogens and further enable the use of solution-based routes for fabricating optoelectronic devices. 相似文献
72.
A new approach to the rapid determination of amoxicillin (AMO) in human plasma followed by solid phase microextraction (SPME) fiber coatings based on conducting polymers (polypyrrole and polythiophene) and high performance liquid chromatography (HPLC) has been described. The porous structures of the electrochemically deposited polymer coatings have been characterized by scanning electron microscopy (SEM). The experimental parameters relating to the extraction efficiency of the SPME fibers such as pH, extraction time and desorption conditions (solvents, time) were studied and selected. The SPME/HPLC-UV method was linear over a working range of 1-50 μg ml(-1). The inter-day accuracy (expressed as coefficients of variations, CVs) was less than 15% and precision (expressed as the relative standard deviations, RSDs) with percentage values was less than 5.9%. Amoxicillin was found to be stable in the human plasma at room temperature (20 °C) within 8 hours. The developed method was successfully applied to the analysis of real human plasma samples. The limit of detection and limit of quantification for amoxicillin in plasma were 1.21 μg ml(-1) and 3.48 μg ml(-1), respectively. 相似文献
73.
74.
Pawel Winter 《Operations Research Letters》2005,33(4):395-402
We give a number of structural results for the problem of constructing a minimum-length 2-connected network for a set of terminals in a graph, where edge-weights satisfy the triangle inequality. A new algorithmic framework, based on our structural results, is given. 相似文献
75.
Pawel J. Kulesza Silvia Zamponi Marcin A. Malik Krzysztof Miecznikowski Mario Berrettoni Roberto Marassi 《Journal of Solid State Electrochemistry》1997,1(1):88-93
Using Prussian blue (PB) electrodeposited on gold-covered foil as a model system, we have demonstrated the usefulness of
the time-derivative measurements of absorbance versus potential (linear potential-scan voltabsorptometry) for spectroelectrochemical
characterization of thin electrochromic films. The time-derivative signals were monitored for PB at 680 and 420 nm in potassium,
sodium and lithium electrolytes. Information obtained from cyclic voltabsorptometry is equivalent or complementary to that
from conventional cyclic voltammetry. In the case of PB films investigated in lithium electrolyte, the voltabsorptometric
time-derivative peaks are better defined than the respective voltammetric peaks. The combination of voltabsorptometry with
voltammetry enables molar absorptivity and/or film loading to be determined. Also, concentration changes of differently colored
mixed-valence redox centers can be monitored as a function of applied potential.
Received: 16 January 1997 / Accepted: 11 March 1997 相似文献
76.
77.
Pawel Winter 《BIT Numerical Mathematics》1985,25(3):485-496
The generalized Steiner problem (GSP) is concerned with the determination of a minimum cost subnetwork of a given network where some (not necessarily all) vertices satisfy certain pairwise (vertex or edge) connectivity requirements.The GSP has applications to the design of water and electricity supply networks, communication networks and other large-scale systems where connectivity requirements ensure the communication between the selected vertices when some vertices and/or edges can become inoperational due to scheduled maintenance, error, or overload.The GSP is known to beNP-complete. In this paper we show that if the subnetwork is required to be biconnected or respectively edge-biconnected, and the underlying network is outerplanar, the GSP can be solved in linear time. 相似文献
78.
Pawel Kruszyński 《Reports on Mathematical Physics》1975,7(3):395-401
The problem of linearity of probability measures on hyperfinite factors is studied in Part I. Part II contains the extension of Vital-Hahn-Saks, Egoroff and Lusic theorems for probability measures on von Neumann algebras. These problems have immediate connections with properties of physical states on observable algebras in the sense of Mackey. 相似文献
79.
Pawel M. Idziak 《Algebra Universalis》1988,25(1):365-383
The aim of this paper is to prove that every finitely generated, arithmetical variety of finite type, in which every subdirectly irreducible algebra has linearly ordered congruences has a decidable first order theory of its finite members. The proof is based on a representation of finite algebras from such varieties by some quotients of special subdirect products in which sets of indices are partially ordered into dual trees. Then the result of M. O. Rabin about decidability of the monadic second order theory of two successors is applied.Presented by Stanley Burris. 相似文献
80.
Jan Purczynski Pawel Rolicz Ryszard Sikora 《Applied Physics A: Materials Science & Processing》1975,8(1):71-74
The method of separation of variables has been applied to determine the magnetic field of the system consisting of a thin ellipsoidal coil and a ferromagnetic ellipsoid of revolution. The inductance and the force acting between the coil and the ellipsoid are also examined. 相似文献