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21.
Oscillations of the input rates of flow have a significant impact on the dynamics of formation of droplets in microfluidic systems and on the quality of generated emulsions. 相似文献
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Rowinska-Zyrek M Witkowska D Bielinska S Kamysz W Kozlowski H 《Dalton transactions (Cambridge, England : 2003)》2011,40(20):5604-5610
The Hpn and HspA proteins from H. pylori are significant for nickel homeostasis and protect the cells from higher concentrations of external metal ions. Both proteins have a unique histidine- and cysteine-rich domain at the C terminus. The interactions of Ni(2+), Bi(3+), Zn(2+) and Cd(2+) ions with C-terminal Ac-CCSTSDSHHQ-NH(2) and Ac-EEGCCHGHHE-NH(2) fragments from Hpn and the Ac-GSCCHTGNHD-NH(2) sequence from HspA were studied by potentiometry, mass spectrometry, circular dichroism and UV-Vis spectroscopy. Ac-CC-NH(2) was used as a reference peptide. The studies have shown that nickel ions form planar complexes with a {2S(-),N(-)} binding mode. The thiol sulfurs of the -Cys-Cys- motif are also the anchoring sites for Bi(3+), Zn(2+) and Cd(2+) ions. The studied protein fragments have the highest affinity for Bi(3+) ions. The thermodynamic stability of Ni(2+) is much higher then that of Zn(2+). 相似文献
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Theoretical search for alternative nine-electron ligands suitable for superhalogen anions 总被引:1,自引:0,他引:1
Sikorska C Freza S Skurski P Anusiewicz I 《The journal of physical chemistry. A》2011,115(10):2077-2085
The calculations performed at the OVGF/6-311++G(3df,3pd)//MP2/6-311++G(d,p) level for the representative NaX(2)(-) and AlX(4)(-) anions matching the MX(k+1)(-) superhalogen formula and utilizing 9-electron systems (i.e., consisting of various possible combinations of atoms containing nine electrons when brought together) revealed that the OH, Li(2)H(3), and NH(2) groups might be considered as alternative ligands X due to their thermodynamic stability and large values of electron binding energy (approaching or even exceeding 6 eV in some cases). All aluminum-containing AlX(4)(-) anions (excluding Al(HBLi)(4)(-)) were predicted to be thermodynamically stable, whereas the NaX(2)(-) anions for X = CH(3), HBLi, CLi, BeB, and H(2)BeLi were found to be susceptible to the fragmentations leading to Na(-) loss. Among the MX(k+1)(-) (M = Na, Al; X = Li(2)H(3), OH, H(2)BeLi, BeB, NH(2), HBLi, CH(3), Be(2)H, CLi) anions utilizing systems containing 9 electrons (and thus isoelectronic with the F atom) the largest vertical electron detachment energy of 6.38 eV was obtained for Al(OH)(4)(-). 相似文献
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We analyze Schr?dinger operators whose potential is given by a singular interaction supported on a sub-manifold of the ambient
space. Under the assumption that the operator has at least two eigenvalues below its essential spectrum we derive estimates
on the lowest spectral gap. In the case where the sub-manifold is a finite curve in two dimensional Euclidean space the size
of the gap depends only on the following parameters: the length, diameter and maximal curvature of the curve, a certain parameter
measuring the injectivity of the curve embedding, and a compact sub-interval of the open, negative energy half-axis which
contains the two lowest eigenvalues.
Dedicated to Krešimir Veselić on the occasion of his 65th birthday.
Submitted: February 20, 2006; Accepted: May 8, 2006 相似文献
26.
A new bioinspired nanomaterial has been obtained by chemisorption of folic acid onto nanocrystalline titanium dioxide. The organic chromophore is linked with the semiconductor surface via the glutamate chain and anchored with the carboxylate group. The geometry and electronic structure of the chromophore was studied in detail with DFT. Photoelectrochemical studies revealed photosensitization of the new material towards visible light. The photoelectrodes composed of the folic acid/titanium dioxide hybrid material generated photocurrent over a 300–600‐nm window. Moreover, the direction of the photocurrent could be changed from anodic to cathodic and vice versa by application of the appropriate photoelectrode potential. Photoelectrochemical and spectroscopic studies allowed the elucidation of the mechanism of photocurrent switching. Photoelectrodes composed of folate‐modified titanium dioxide may serve as a simple model of optoelectronic switches and may constitute the basis for molecular photoelectronic devices. 相似文献
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A set of intramolecularly connected dyads consisting of a quinone unit and a pyrrole or indole moiety have been designed and evaluated in quantum-chemical calculations. It is shown computationally for several systems, depending on the length and attachment points of the interconnecting chains, that a reduction of the quinone to the semiquinone radical anion or quinolate dianion state leads to a reversible intramolecular reorientation from a pi-stacked to a T-stacked arrangement. In the rearranged structures, a hydrogen bond from the pyrrole or indole N-H function to the semiquinone or quinolate pi-system is created upon reduction. In some systems, hydrogen bonds to the semiquinone or quinolate oxygen atoms are partly feasible and will be preferred over T-stacking. The choice of systems has been based on recent computational observations related to photosystem I. Systems with pyrrole or indole units should provide a better basis for the envisioned molecular motor than recently proposed quinone-benzene dyads. The intramolecular interactions modify the quinone redox potentials. Electronic g-tensors have been computed for the semiquinone states. These reflect characteristically the presence and nature of hydrogen bonds to the semiquinone and represent suitable electron paramagnetic resonance spectroscopic probes for the preferred structures. Intramolecular proton transfer is possible in the dianionic state. 相似文献
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Sylwia Mozia Ewa Borowiak-Paleń Barbara Grzmil Masahiro Toyoda Antoni W. Morawski 《Journal of Physics and Chemistry of Solids》2010,71(3):263-26
Titanate nanotubes (TNTs) were prepared from TiO2 P25 via hydrothermal method. The reaction temperature was 130 or 140 °C and the reaction time was 24 or 48 h. The samples were characterized by transmission electron microscopy, X-ray diffraction, thermogravimetry and N2 adsorption as well as Raman, FTIR-DRS and UV-vis/DR spectroscopy. The obtained samples exhibited similar properties, regardless of the preparation temperature and time. The most notable difference between properties of TNTs prepared under different conditions was observed in case of BET surface area, which was increasing from 386 to 478 m2/g along with increasing the reaction time and temperature. Based on TEM, XRD and TG measurements we have suggested that the structure of TNTs was H2Ti2O4(OH)2. The TEM and Raman spectroscopy measurements showed that the obtained products contained also low amount of anatase phase. The TNTs exhibited no photoactivity towards degradation of model azo dye Acid Red 18. However, TNTs were successfully applied for photocatalytic generation of CH4 and H2 in a solution of acetic acid. The amount of methane produced with application of TNTs synthesized at 140 °C was about 2.5 times higher than that generated with use of TiO2 P25. To the best of our knowledge this is a first report on the photocatalytic generation of hydrocarbons using TNTs in the current state of the art. 相似文献
29.
The Liouville-type theorem for problems with nonstandard growth derived by Caccioppoli-type estimate
Sylwia Dudek 《Monatshefte für Mathematik》2020,192(1):75-91
Let u be a nonnegative solution to the PDI $$-\,\mathrm{div} \mathcal {A}(x, u, \nabla u)\geqslant \mathcal {B}(x,u, \nabla u)$$ in $$\Omega $$, where $$\mathcal {A}$$ and $$\mathcal {B}$$ are differential operators with p(x)-type growth. As a consequence of the Caccioppoli-type inequality for the solution u, we obtain the Liouville-type theorem under some integral condition. We simplify the assumptions on functions $$ \mathcal {A}$$ and $$ \mathcal {B}$$, and we do not restrict the range of p(x) by the dimension n, therefore we can cover quite general family of problems. 相似文献
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