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1.
Sang Chul Shim Chil Hoon Doh Tae Jeong Kim Hak Ki Lee Ki Doo Kim 《Journal of heterocyclic chemistry》1988,25(5):1383-1385
Ethanolic tetracarbonylhydridoferrate combined with adipaldehyde is very efficient for the selective transformation of an amino group into perhydroazepine. A large variety of both aliphatic and aromatic amines react with adipaldehyde in the presence of tetracarbonylhydridoferrate at room temperature and carbon monoxide to give the corresponding N-alkyl- and N-arylperhydroazepines in good to excellent yields. 相似文献
2.
It is thought that the therapeutic efficacy of Morus alba L. is determined by its biological compounds. We investigated the chemical differences in the medicinal parts of M. alba by analyzing a total of 57 samples (15 root barks, 11 twigs, 12 fruits, and 19 leaves). Twelve marker compounds, including seven flavonoids, two stilbenoids, two phenolic acids, and a coumarin, were quantitatively analyzed using a high-performance liquid chromatography-diode array detector and chemometric analyses (principal component and heatmap analysis). The results demonstrated that the levels and compositions of the marker compounds varied in each medicinal part. The leaves contained higher levels of six compounds, the root barks contained higher levels of four compounds, and the twigs contained higher levels of two compounds. The results of chemometric analysis showed clustering of the samples according to the medicinal part, with the marker compounds strongly associated with each part: mulberroside A, taxifolin, kuwanon G, and morusin for the root barks; 4-hydroxycinnamic acid and oxyresveratrol for the twigs and skimmin; chlorogenic acid, rutin, isoquercitrin, astragalin, and quercitrin for the leaves. Our approach plays a fundamental role in the quality evaluation and further understanding of biological actions of herbal medicines derived from various medicinal plant parts. 相似文献
3.
Multiwall carbon nanotubes (MWNTs) were synthesized in supercritical toluene at 600 degrees C and approximately 12.4 MPa using ferrocene, Fe, or FePt nanocrystals as growth catalysts. Toluene serves as both the carbon source for nanotube formation and the solvent. In contrast to vapor-phase synthetic routes, the supercritical solvent provides high precursor concentration and a homogeneous reaction environment with dispersed growth catalyst particles. Both carbon filaments and MWNTs are produced by this approach, and a growth mechanism is proposed to explain the factors that determine the nanotube versus filament morphology. The plasmon energies of the pi and pi + sigma valence electrons were measured using electron energy-loss spectroscopy (EELS) of individual carbon fibers and MWNTs as a characterization tool to complement the imaging data obtained from electron microscopy. 相似文献
4.
M.J. Šćepanović M. Grujić-Brojčin Z.D. Dohčević-Mitrović Z.V. Popović 《Applied Physics A: Materials Science & Processing》2007,86(3):365-371
Nanosized titanium dioxide (TiO2) powder was prepared by a laser-induced pyrolysis. Specific surface area of the as-grown powder measured by BET method was
109 m2/g. The grain size (14.5 nm) estimated from these data coincides well with the crystallite size (12.3 nm) determined by XRD
measurements. The average grain size (∼35 nm) obtained from the subsequent SEM measurements refers to considerable agglomeration
of nanoparticles. Raman spectroscopy has been used to investigate the structural properties of TiO2 nanopowder and its anatase structure is confirmed. The blueshift and broadening of the lowest frequency Eg Raman mode at temperature range ∼25–550 K have been analyzed using a phonon-confinement model. Dominant influence of the
strong anharmonic effect at higher temperatures was demonstrated.
PACS 81.07.Wx; 78.30.-j; 63.22.+m 相似文献
5.
4D-PTV system was constructed. The measurement system consists of three high-speed high-definition cameras (1k × 1k, 2000
fps), Nd-Yag laser (2000 Hz) and a host computer. The GA-3D-PTV algorithm was used for completing the measurement system.
The 4D-PTV is capable of probing the spatial distribution of velocity vectors of the flow field overcoming the temporal resolution
of the characteristic turbulence length scales of the measured flow fields. A horizontal impinged jet flow (H/D = 7) was measured.
The Reynolds number is about 33,000. Spatial temporal evolution of the jet flow was examined and physical properties such
as spatial distributions of vorticity and turbulent kinetic energy were obtained with the constructed system. 相似文献
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7.
Ko In-Yong Kim Na-Ri Lee Jin-Yeoung Park Na-Ra Doh Jung-Mann Shon In-Jin 《Research on Chemical Intermediates》2010,36(6-7):775-784
Nanopowders of Cu and Al2O3 were synthesized from 3CuO and 2Al powders by high-energy ball milling. Nanocrystalline Al2O3 reinforced composite was consolidated by pulsed-current activated sintering method within 2 min from mechanically synthesized powders of Al2O3 and Cu. The relative density of the composite was 96%. The average hardness and fracture toughness values obtained were 540 kg/mm2 and 6.3 MPa m1/2, respectively.
相似文献8.
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10.
Kwon KW Choi JC Suh KY Doh J 《Langmuir : the ACS journal of surfaces and colloids》2011,27(7):3238-3243
We present new methods that enable the fabrication of multiscale, multicomponent protein-patterned surfaces and multiscale topologically structured surfaces by exploiting the merits of two well-established techniques: capillary force lithography (CFL) and microscope projection photolithography (MPP) based on a protein-friendly photoresist. We further demonstrate that, when hierarchically organized micro- and nanostructures were used as a cell culture platform, human colon cancer cells (cell line SW480) preferentially adhere and migrate onto the area with nanoscale topography over the one with microscale topography. These methods will provide many exciting opportunities for the study of cellular responses to multiscale physicochemical cues. 相似文献