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排序方式: 共有809条查询结果,搜索用时 15 毫秒
81.
Mediterranean Journal of Mathematics - Using GTW connection, we considered a real hypersurface M in a complex two-plane Grassmannian $${G_{2}({mathbb{C}}^{m+2})}$$ when the GTW Reeb Lie derivative... 相似文献
82.
S.-Y. Lee T.-H. Kim D.-I. Suh E.-K. Suh N.-K. Cho W.-K. Seong S.-K. Lee 《Applied Physics A: Materials Science & Processing》2007,87(4):739-742
We demonstrate GaN nanowire (NW) current rectifiers which were formed by assembling n-GaN nanowires on a patterned p-Si substrate
by means of alternating current (ac) dielectrophoresis. The dielectrophoresis was accomplished at a frequency of 10 kHz with
three different ac bias voltages (5, 10, and 15 Vp–p), indicating that the number of aligned GaN nanowires increased with increasing ac bias voltage. The n-GaN NW/p-Si diodes
showed well-defined current rectifying behavior with a forward voltage drop of 1.2–1.5 V at a current density of 200 A/cm2. We observed that the GaN NW diode functioned well as a half-wave rectifier.
PACS 71.20.Nr; 73.40.Cg; 73.40.Ei; 73.40.Kp 相似文献
83.
Song HT Choi JS Huh YM Kim S Jun YW Suh JS Cheon J 《Journal of the American Chemical Society》2005,127(28):9992-9993
High-quality biocompatible magnetic iron oxide (Fe3O4) nanocrystals were developed through a ligand exchange process of hydrophobically capped nanocrystals with hydrophilic molecules. By simple modulation of the nanocrystal surface ligand charge properties, we have been able to prepare magnetic nanocrystals with excellent intracellular labeling capabilities that efficiently label a variety of cell types without the need for additional transport facilitating agents. The excellent intracellular labeling capability of the newly developed cationic WSIO has further led to successful MRI monitoring of the migration of neural stem cells in rat spinal cord. The magnetic nanocrystals developed here have great potential in applications for labeling of various cell types and also the monitoring of cell-based medical treatments and cancer metastasis. 相似文献
84.
Correlated atomic force microscopy and fluorescence lifetime imaging of live bacterial cells 总被引:3,自引:0,他引:3
Micic M Hu D Suh YD Newton G Romine M Lu HP 《Colloids and surfaces. B, Biointerfaces》2004,34(4):205-212
We report on imaging living bacterial cells by using a correlated tapping-mode atomic force microscopy (AFM) and confocal fluorescence lifetime imaging microscopy (FLIM). For optimal imaging of Gram-negative Shewanella oneidensis MR-1 cells, we explored different methods of bacterial sample preparation, such as spreading the cells on poly-L-lysine coated surfaces or agarose gel coated surfaces. We have found that the agarose gel containing 99% ammonium acetate buffer can provide sufficient local aqueous environment for single bacterial cells. Furthermore, the cell surface topography can be characterized by tapping-mode in-air AFM imaging for the single bacterial cells that are partially embedded. Using in-air rather than under-water AFM imaging of the living cells significantly enhanced the contrast and signal-to-noise ratio of the AFM images. Near-field AFM-tip-enhanced fluorescence lifetime imaging (AFM-FLIM) holds high promise on obtaining fluorescence images beyond optical diffraction limited spatial resolution. We have previously demonstrated near-field AFM-FLIM imaging of polymer beads beyond diffraction limited spatial resolution. Here, as the first step of applying AFM-FLIM on imaging bacterial living cells, we demonstrated a correlated and consecutive AFM topographic imaging, fluorescence intensity imaging, and FLIM imaging of living bacterial cells to characterize cell polarity. 相似文献
85.
T. S. Kim T. V. Cuong C. S. Park J. Y. Park H. J. Lee E. -K. Suh C. -H. Hong 《Journal of Crystal Growth》2004,260(3-4):336-342
GaAs1−xNx epilayers were grown on a GaAs(0 0 1) substrate by metalorganic chemical vapor deposition. Composition was determined by high resolution X-ray diffraction. Band gap was measured from 77 to 400 K by using photocurrent measurements. The photocurrent spectra show clear near-band-edge peak and their peak energies drastically decrease with increasing nitrogen composition due to band gap bowing in the GaAs1−xNx epilayers. Those red shifts were particularly notable for low nitrogen compositions. However, the shifts tended to saturate when the nitrogen composition become higher than 0.98%. When the nitrogen composition is in the range 1.68–3.11%, the measured temperature dependence of the energy band gap was nicely fitted. However, the properties for the nitrogen composition range 0.31–0.98% could not be fitted with a single fitting model. This result indicates that the bowing parameter reaches 25.39 eV for low nitrogen incorporation (x=0.31%), and decreases with increasing nitrogen composition. 相似文献
86.
A 3D porous metal-organic framework [Zn3(ntb)2(EtOH)2]n.4nEtOH (1) that generates 1D channels of honeycomb aperture has been prepared by the solvothermal reaction of Zn(NO3)(2).6 H2O and 4,4',4'-nitrilotrisbenzoic acid (H3NTB) in EtOH at 110 degrees C. Framework 1 exhibits reversible single-crystal-to-single-crystal transformations upon removal and rebinding of the coordinating EtOH as well as the EtOH guest molecules, which give rise to desolvated crystal [Zn3(ntb)2]n (1') and resolvated crystal [Zn3(ntb)2-(EtOH)2]n.4nEtOH (1'). The X-ray structures indicate that 3D host framework is retained during the transformations from 1 to 1' and from 1' to 1', but the coordination geometry of ZnII ions changes from/to trigonal bipyramid to/from tetrahedron, concomitant with the rotational rearrangement of a carboxylate plane of the NTB3- relative to its associated phenyl ring. To retain the single crystal integrity, extensive cooperative motions must exist between the molecular components throughout the crystal. Framework 1' exhibits permanent porosity, thermal stability up to 400 degrees C, and blue luminescence, and high storage capabilities for N2, H2, CO2, and CH4. 相似文献
87.
In this paper, first we introduce a new notion of commuting condition that φφ 1 A = A φ 1 φ between the shape operator A and the structure tensors φ and φ 1 for real hypersurfaces in G 2(? m+2). Suprisingly, real hypersurfaces of type (A), that is, a tube over a totally geodesic G 2(? m+1) in complex two plane Grassmannians G 2(? m+2) satisfy this commuting condition. Next we consider a complete classification of Hopf hypersurfaces in G 2(? m+2) satisfying the commuting condition. Finally we get a characterization of Type (A) in terms of such commuting condition φφ 1 A = A φ 1 φ. 相似文献
88.
KY Fan 《Linear and Multilinear Algebra》1973,1(1):1-4
Inequalities concerning real square matrices A with positive definite symmetric component A+A*are derived from certain inertia relations which hold for any complex (not necessarily real) square matrices A with positive definite
A+A* 相似文献
A+A* 相似文献
89.
1,3-diproyloxycalix[4]arene azacrown ether was successfully synthesized in the fixed 1,3-alternate conformation which was confirmed by a solid state structure. 相似文献
90.
In this paper we consider a new notion of ${\mathfrak{D}^{\bot}}$ -parallel shape operator for real hypersurfaces in complex two-plane Grassmannians ${G_2(\mathbb{C}^{m+2})}$ and give a non-existence theorem for a Hopf hypersurface in ${G_2(\mathbb{C}^{m+2})}$ with ${\mathfrak{D}^{\bot}}$ -parallel shape operator. 相似文献