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81.
Marian Kubliha Viera Trnovcov Ivan Furr Magdalna Kadle
íkov Jitka Pedlíkov Jn Gregu 《Journal of Non》2009,355(37-42):2035-2039
The influence of crucibles (Au or Pt) on the structure, electrical, dielectric and optical properties of 70TeO2·30PbCl2 glasses doped with Pr3+ added as a metal, chloride, or oxide, in concentrations of 500–1500 wt-ppm, is reported. The dc conductivity of ‘pure’ glasses prepared in Au crucibles is two orders of magnitude higher than that of those prepared in Pt crucibles. Upon doping, the dc conductivity of glasses prepared in Pt and Au crucibles increases or decreases, respectively. The static relative permittivity is equal to 33 ± 2. In the range of 640–700 nm, six photoluminescence (PL) peaks were observed, at 641.5, 647.1, 652.4, 660.8, 662.9, and 664.5 nm. In the range of 200–1200 cm−1, seven Raman scattering (RS) peaks were observed at 184, 217, 321, 468, 654, 735 cm−1, and a small peak at 650 cm−1. Both spectra were deconvoluted using symmetrical Gaussian functions. Relative intensities of PL and RS bands depend on the concentration and chemical form of Pr3+ and on the material of the crucible. However, positions of these bands are independent of these conditions. 相似文献
82.
The motion of a red blood cell suspended in blood plasma in a two-beam plane interference field was studied experimentally. A cw Argon Ion laser was used. A model is proposed to describe the observed motion. The model is based on a balance between the optical gradient force and the drag force, and yields the location of the cell as a function of time, starting from a stationary position at an arbitrary distance from a dark fringe until becoming trapped at the center of the closest bright fringe. It is suggested that the discrepancy between the predictions of the model and the observed motion is attributable to the influence of the wall close to which the cell flows. 相似文献
83.
Recent research has revealed a rich and complicated network topology in the cortical connectivity of mammalian brains. A challenging
task is to understand the implications of such network structures on the functional organisation of the brain activities.
We investigate synchronisation dynamics on the corticocortical network of the cat by modelling each node of the network (cortical
area) with a subnetwork of interacting excitable neurons. We find that this network of networks displays clustered synchronisation
behaviour and the dynamical clusters closely coincide with the topological community structures observed in the anatomical
network. The correlation between the firing rate of the areas and the areal intensity is additionally examined. Our results
provide insights into the relationship between the global organisation and the functional specialisation of the brain cortex.
相似文献
84.
85.
Capillary electrophoresis with diode array detection (DAD) was used to determine uric acid (UA) in chicken plasma and the allantoic fluid of chicken embryos. Complete separation of uric and ascorbic acids was attained in less than 10 min in the optimized BGE containing 60 mM MES + 30 mM Tris + 0.001% (w/v) polybrene (pH 6.1). The limit of UA detection (0.2 mg/L) was found to be low enough for sensitive analysis of native plasma and allantoic fluid samples. Range of linearity (1-200 mg/L), repeatability for peak area (CV <4.1%) and migration time (CV < 2.5%), as well as recovery of UA from biological samples (97-100%), were found to be satisfactory. The method was applied to detect the elevated UA concentrations (hyperuricemia) in chicken embryos with induced unilateral renal agenesis. CE/DAD analysis of the chicken plasma can be carried out with a relatively small volume of samples (1 microL). 相似文献
86.
Baran EJ Viera I Torre MH 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,66(1):114-117
The infrared and Raman spectra of the copper(II) complexes [Cu(L-asn)2] and [Cu(L-gln)2] (L-asn=L-asparagine; L-gln=L-glutamine), were recorded and analyzed in relation to its structural peculiarities. Some comparisons between the spectra of these complexes and with those of related systems are made. The characteristics of the carboxylate and amide groups of the bonded ligands are discussed in detail. 相似文献
87.
Wangsa Tirta Ismaya Khomaini Hasan Idar Kardi Amalia Zainuri Rinrin Irma Rahmawaty Satyawisnu Permanahadi Baiq Vera El Viera Gunawan Harinanto Shabarni Gaffar Dessy Natalia Toto Subroto Soetijoso Soemitro 《Applied biochemistry and biotechnology》2013,170(1):44-57
α-Amylase catalyzes hydrolysis of starch to oligosaccharides, which are further degraded to simple sugars. The enzyme has been widely used in food and textile industries and recently, in generation of renewable energy. An α-amylase from yeast Saccharomycopsis fibuligera R64 (Sfamy) is active at 50 °C and capable of degrading raw starch, making it attractive for the aforementioned applications. To improve its characteristics as well as to provide information for structural study ab initio, the enzyme was chemically modified by acid anhydrides (nonpolar groups), glyoxylic acid (GA) (polar group), dimethyl adipimidate (DMA) (cross-linking), and polyethylene glycol (PEG) (hydrophilization). Introduction of nonpolar groups increased enzyme stability up to 18 times, while modification by a cross-linking agent resulted in protection of the calcium ion, which is essential for enzyme activity and integrity. The hydrophilization with PEG resulted in protection against tryptic digestion. The chemical modification of Sfamy by various modifiers has thereby resulted in improvement of its characteristics and provided systematic information beneficial for structural study of the enzyme. An in silico structural study of the enzyme improved the interpretation of the results. 相似文献
88.
Peter Segl’a Jozef Miklovič Dušan Mikloš Ján Titiš Radovan Herchel Ján Moncol Barbora Kaliňáková Daniela Hudecová Viera Mrázová Tadeusz Lis Milan Melník 《Transition Metal Chemistry》2008,33(8):967-974
Synthesis and characterization of 10 new 2-methylthionicotinate (2-MeSnic) Co(II) complexes, namely, [Co(2-MeSnic)2L2(H2O)2] · nH2O (L is N,N-diethylnicotinamide—Et2nia, ethylnicotinate—Etnic, nicotinamide—nia, isonicotinamide—isonia, N-methylnicotinamide—N-Menia, furo[3,2-c]pyridine—fpy, 2,3-dimethylfuro[3,2-c]pyridine—Me2fpy or benzo[4,5]furo[3,2-c]pyridine—Bfp; n is 0, 1 or 2) as well as [Co(2-MeSnic)2L2] (L is ronicol—ron or 2-methylfuro[3,2-c]pyridine—Mefpy), are reported. The characterizations were based on physico-chemical
and spectroscopic methods. The crystal structure of one of the complexes has been determined. In the molecular complex [Co(2-MeSnic)2(Me2fpy)2(H2O)2], the Co(II) central atom, located at a symmetry centre, is octahedrally coordinated by an oxygen atom of the unidentate
2-MeSnic carboxyl group, the nitrogen atom of the pyridine ring of Me2fpy, a water molecule and the corresponding centrosymmetrically located atoms. Also, biological activity of the complexes
against various strains of bacteria and filamentous fungi has been investigated. It is concluded that by complexation of these
nicotinate derivatives their biological activities are elevated.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
89.
Time-discretization scheme for quasi-static Maxwell's equations with a non-linear boundary condition
We study a time dependent eddy current equation for the magnetic field H accompanied with a non-linear degenerate boundary condition (BC), which is a generalization of the classical Silver–Müller condition for a non-perfect conductor. More exactly, the relation between the normal components of electrical E and magnetic H fields obeys the following power law ν×E=ν×(|H×ν|α-1H×ν) for some α∈(0,1]. We establish the existence and uniqueness of a weak solution in a suitable function space under the minimal regularity assumptions on the boundary Γ and the initial data H0. We design a non-linear time discrete approximation scheme based on Rothe's method and prove convergence of the approximations to a weak solution. We also derive the error estimates for the time-discretization. 相似文献
90.
Vladimir Labaš Marcel Poulain Marian Kubliha Stanislav Minárik Salem Chaguetmi Jozef Psota Viera Trnovcová 《Journal of Non》2011,357(11-13):2371-2374
Glass samples have been prepared in the NaPO3–KHSO4 binary system with the classical melting, casting and annealing steps. Electrical and dielectrical properties of glass samples were studied. Measurements of DC and AC conductivity and complex electrical permittivity of xNaPO3–(100 ? x)KHSO4 glass system were carried out at temperatures ranging from room temperature to temperature located 15 °C below glass transition temperature Tg. Results showed that changes of NaPO3 concentration considerably affect values of observed parameters. DC conductivity of glass increases as NaPO3 concentration grows until concentration x = 60. However, beyond this value a sharp decrease of DC conductivity was observed. In addition relaxation times showed abrupt changes at concentration x = 60, corresponding to the lowest relaxation times at the temperature 90 °C. 相似文献