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991.
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993.
Two new compounds, a cyclic peptide desmocyclopeptide (1) and a special flavone desmorostratone (2) were isolated from the stem bark of Desmos rostrata, along with two known compounds, desmosdumotins B (3) and C (4). Their structures were established on the basis of the spectral data, including mass spectrometry and 2D NMR. The total synthesis of desmorostratone (2) was performed in order to confirm its structure as well as that of desmosdumotin C (4), which was a tautomeric mixture in the solution. Finally, cytotoxity of these compounds were evaluated. Desmosdumotin C (4) displayed a moderate inhibition activity against KB cell line with an IC50 of 19.2 μM, whereas the other products showed a weak inhibition against the same cell line target. 相似文献
994.
Growth of single-crystalline sodium titanate and sodium tungstate one-dimensional nanostructures: Bio-inspired approach using oyster shell 总被引:1,自引:0,他引:1
Using oyster shell, single-crystalline Na2Ti6O13 and Na2W4O13 one-dimensional nanostructures (ODNS) were simply synthesized from granular TiO2 and WO3 particles by thermal heating at 700 °C. The oyster shell was used as a source of both sodium and carbon dioxide, which have an effect on unidirectional growth of single-crystalline Na2Ti6O13 and Na2W4O13 from TiO2 and WO3. The growth of sodium metal oxide ODNS from metal oxide particles was reproduced by replacing oyster shell with chemical reagents (NaCl, CaCO3) or gas (CO2), allowing identification of the main factors for the growth of ODNS. The characteristics of biological material (i.e., oyster shell) lend certain advantages in the fabrication of sodium metal oxide ODNS: (a) low processing temperature with high yield; (b) an eco-friendly method; and (c) no requirement of additional processes such as separation or washing. This work suggests a new approach for using biological material for the crystal growth of nanostructured materials. 相似文献
995.
S. Henin Y. Petit J. Kasparian J.-P. Wolf A. Jochmann S. D. Kraft S. Bock U. Schramm R. Sauerbrey W. M. Nakaema K. Stelmaszczyk P. Rohwetter L. W?ste C.-L. Soulez S. Mauger L. Bergé S. Skupin 《Applied physics. B, Lasers and optics》2010,100(1):77-84
We experimentally and numerically characterize multiple filamentation of laser pulses with incident intensities of a few TW/cm2. Propagating 100 TW laser pulses over 42 m in air, we observe a new propagation regime where the filament density saturates. As also evidenced by numerical simulations in the same intensity range, the total number of filaments is governed by geometric constraints and mutual interactions among filaments rather than by the available power in the beam. 相似文献
996.
Eric Grelet Sébastien Dardel Harald Bock Michel Goldmann Emmanuelle Lacaze Frédéric Nallet 《The European physical journal. E, Soft matter》2010,31(4):343-349
The structure and the orientation of thermotropic hexagonal columnar liquid crystals are studied by grazing incidence X-ray
diffraction (GIXD) for different discotic compounds in the geometry of open supported thin films. Whatever the film deposition
mode (either spin-coating or vacuum evaporation) and the film thickness, a degenerate planar alignment with the liquid crystalline
columns parallel to the substrate is found. However, if a specific thermal process is applied to the liquid crystal film,
homeotropic anchoring (columns normal to the interface) can be stabilized in a metastable state. 相似文献
997.
We analyze a simple local search heuristic for the facility location problem using the notion of perturbation resilience: an instance is -perturbation resilient if all costs can be perturbed by a factor of without changing the optimal solution.We prove that local search for FLP succeeds in finding the optimal solution for -perturbation resilient instances for , and we show that this is tight. 相似文献
998.
A patterned metal thin film was synthesized based on a new approach that allows the formation of thin films with complex shape, hierarchical organization, and controlled size under ambient conditions in an aqueous environment. By using a general coating system, a CaCO3 thin film was transformed into a patterned metal thin film with functional properties, such as adhesion and hydrophobicity. Atomic force microscopy (AFM) and surface-profiling experiments were carried out to measure the adhesion between the probe tip and the substrate and to determine the film thickness. Separation of the patterned ceramic thin film occurred very easily by means of sputtering and chemical treatment with an acidic solution. 相似文献
999.
Cover Picture: Lamellar versus Micellar Structures—Aggregation Behavior of a Three‐Chain Cationic Lipid Designed for Nonviral Polynucleotide Transfer (ChemPhysChem 10/2015) 下载免费PDF全文
1000.