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81.
Husale BS Sahoo S Radenovic A Traversi F Annibale P Kis A 《Langmuir : the ACS journal of surfaces and colloids》2010,26(23):18078-18082
We used AFM to investigate the interaction of polyelectrolytes such as ssDNA and dsDNA molecules with graphene as a substrate. Graphene is an appropriate substrate due to its planarity, relatively large surfaces that are detectable via an optical microscope, and straightforward identification of the number of layers. We observe that in the absence of the screening ions deposited ssDNA will bind only to the graphene and not to the SiO(2) substrate, confirming that the binding energy is mainly due to the π-π stacking interaction. Furthermore, deposited ssDNA will map the graphene underlying structure. We also quantify the π-π stacking interaction by correlating the amount of deposited DNA with the graphene layer thickness. Our findings agree with reported electrostatic force microscopy (EFM) measurements. Finally, we inspected the suitability of using a graphene as a substrate for DNA origami-based nanostructures. 相似文献
82.
Bloch et al. mapped the precession of the spin-half in a magnetic field of variable magnitude and direction to the rotations of a rigid sphere rolling on a curved surface utilizing SU(2)–SO(3) isomorphism. This formalism is extended to study the behaviour of spin–orbit interactions and the mechanical analogy for Rashba–Dresselhauss spin–orbit interaction in two dimensions is presented by making its spin states isomorphic to the rotations of a rigid sphere rolling on a ring. The change in phase of spin is represented by the angle of rotation of sphere after a complete revolution. In order to develop the mechanical analogy for the spin filter, we find that perfect spin filtration of down spin makes the sphere to rotate at some unique angles and the perfect spin filtration of up spin causes the rotations with certain discrete frequencies. 相似文献
83.
P. Shanmugavadivu V. Sivakumar Rashmi Sudhir 《The European physical journal. Special topics》2016,225(1):137-146
A new Fractal Dimension-based diagnosis technique for the change detection and time-series analysis of masses in the temporal digital mammogram is presented in this paper. As the digital mammograms are confirmed as a reliable source for the prognosis of breast cancer, the demand for the development of precise computer aided detection techniques is constantly on the increase. This formed the basis for the development of this method using Fractal geometry, which is an efficient mathematical approach that deals with self-similar and irregular geometric objects called fractals. This work comprises of the detection of spatial masses using Fractal Hurst bound enhancement and segmentation of those temporal masses using Fractal Thresholding. The consultant radiologist’s assessment of mass lesions forms the baseline for comparison and validation of the detected masses. Further, this research work performs temporal analysis of mass lesions, detected from the mammograms of the current and the respective prior view using the principle of Fractal Dimension. The precision of Fractal-dimension based temporal texture analysis of malignant masses of digital mammograms subsequently attributes to their characterization. 相似文献
84.
Jalpa C. Trivedi Kuldip D. Upadhyay Sudhir K. Joshi Erik De Clercq 《Tetrahedron letters》2007,48(48):8472-8474
Two closely structurally related coumarins, 4-hydroxy-8-isopropyl-5-methylcoumarin and 4-hydroxy-6-chloro-7-methylcoumarin were acylated at C-3 and further converted to the respective chalcones and two series of eighteen new compounds, which were evaluated for possible antiviral activity. 相似文献
85.
Sudhir Hande Adelphe Mfuh Scott Throner Ye Wu Qing Ye XiaoLan Zheng 《Tetrahedron letters》2019,60(41):151100
A new photoredox-catalyzed CN coupling reaction of sulfoximines with aryl halides has been developed for a general N-arylation of sulfoximines. The reactions proceed in the presence of visible light with high levels of chemoselectivity and a wide range of functionality is tolerated. There is a rapidly increasing interest in sulfoximines as pharmacophores in drug discovery and this new method offers potential in terms of high functional group tolerance and late-stage functionalization of compounds. 相似文献
86.
87.
We consider the Littlest Higgs Model with T-parity (LHT), in the parameter region where a heavy neutrino is the lightest T-odd particle (LTP). Having emphasized that this corresponds to a sizable region in the parameter space of the theory, we show that both the Cryogenic Dark Matter Search (CDMS) and Xenon10 experiments disallow the entire region where the masses of the new particles in LHT can lie within several TeV. Therefore, any observation of the signals of a heavy neutrino LTP is likely to seriously reopen the issue of cold dark matter in the universe. 相似文献
88.
This paper describes an effect of flow rate, carrier gas (H2, N2 and Ar) composition, and amount of benzene on the quality and the yield of carbon nanotubes (CNTs) formed by catalytical
vapour dcomposition (CVD) method. The flow and mass control of gases and precursor vapors respectively were found to be interdependent
and therefore crucial in deciding the quality and yield of CNTs. We have achieved this by modified soap bubble flowmeter,
which controlled the flow rates of two gases, simultaneously. With the help of this set-up, CNTs could be prepared in any
common laboratory. Raman spectroscopy indicated the possibilities of formation of single-walled carbon nanotubes (SWNTs).
From scanning electron microscopy (SEM) measurements, an average diameter of the tube/bundle was estimated to be about 70
nm. The elemental analysis using energy dispersion spectrum (EDS) suggested 96 at.wt.% carbon along with ca. 4 at.wt.% iron
in the as-prepared sample. Maximum yield and best quality CNTs were obtained using H2 as the carrier gas.
相似文献
89.
Hert DG Anderson JL Aki SN Brennecke JF 《Chemical communications (Cambridge, England)》2005,(20):2603-2605
The presence of CO(2) increases the solubility of O(2) and CH(4) in 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide at 25 degrees C and pressures to 13 bar. 相似文献
90.
A generalized VMD mechanism, implemented through the OPC model, is proposed for E1 and M1 decays of mesons wherein the photon couples to two infinite sequences of radial excitations of 3S1 and 3D1 states. The results reveal good accord with data under the conventional assignments, with a parameter signifying a reduced magnetic coupling of ψ-ions with c quarks. 相似文献