High resolution angle-resolved photoemission spectroscopy data along the (0,0)-(pi,pi) nodal direction with significantly improved statistics reveal fine structure in the electron self-energy of the underdoped (La2-xSrx)CuO4 samples in the normal state. Fine structure at energies of (40-46) meV and (58-63) meV, and possible fine structure at energies of (23-29) meV and (75-85) meV, have been identified. These observations indicate that, in (La2-xSrx)CuO4, more than one bosonic modes are involved in the coupling with electrons. 相似文献
A novel nanodiamond-epoxy derivative(ND-EP) was synthesized by grafting epoxy monomers onto the surface of nanodiamond(ND),and characterized by FTIR and TGA.The ratio of grafted epoxy groups was determined to be 32.5 wt% by TGA.The developed methodology provides an efficient method for the functionalization of nanodiamond material,which enables a variety of advanced engineering and biomedical applications of ND. 相似文献
A novel Selectfluor-mediated copper-catalyzed highly selective benzylic C-O cyclization for the synthesis 4H-3,1-benzoxazines is reported. The predominant selectivity for a benzylic C(sp(3))-H over an aromatic C(sp(2))-H bond in N-o-tolylbenzamides is achieved. 相似文献
Heusler phases, including the full- and half-Heusler families, represent an outstanding class of multifunctional materials on account of their great tunability in compositions, valence electron counts (VEC), and properties. Here we demonstrate a systematic design of a series of new compounds with a 2×2×2 superstructure of the half-Heusler unit cell in X-Y-Z (X=Fe, Ru, Co, Rh, Ir; Y=Zn, Mn; Z=Sn, Sb) systems. Their structures were solved by using both powder and single-crystal X-ray diffraction, and also directly observed by using high-angle annular dark-field imaging in a scanning transmission electron microscope (HAADF-STEM). The VEC values of these new compounds span a wide and continuous range comparable to those for the full- and half-Heusler families, thereby implying tunability in compositions and physical properties in the superstructure. In fact, we observed abnormal electrical properties and a ferromagnetic semiconductor-like behavior with a high and tunable Curie temperature in these superstructures. 相似文献
A novel C18 functionalized graphene oxide (GO) coated solid-phase microextraction fiber was prepared by a novel protocol. Based on the strong van der Waals interaction present in GO and abundant oxygenous groups in GO sheets, a simple layer-by-layer self-assembly method was used in the preparation process and then C18 was successfully self-assembled on GO via C-O-Si bonding. Coupled with gas chromatography, extraction performance of the fiber was tested with polycyclic aromatic hydrocarbons (PAHs) as model analytes. The fiber not only exhibited excellent extraction efficiency and selectivity, but also showed many advantages including high rigidity, long service life and well stability toward organic solvent, acidic and alkali solutions, and high temperature. The relative standard deviations for single-fiber repeatability and fiber-to-fiber reproducibility were less than 7.26 and 17.25%, respectively. The detection limits to the PAHs were less than 0.08 μg L(-1) and the calibration curves were linear in a wide range for all analytes. The as-established Solid-phase microextraction GC method was also successfully used for determination of PAHs in two real water samples. 相似文献
A new methodology is developed to conjugate hyaluronic acid (HA) hydrogel with novel nano‐fibrous architectures via non‐covalent assembly that specifically allows for targeted adipose‐derived stem cells (ASCs) differentiation and soft tissue engineering. The assembly of non‐covalently associated hydrogel network produced via the interaction of a low molecular weight heparin (LMWH) modified HA derivative and heparin interacting protein (HIP). The multifunctional star poly(ethylene glycol) (PEG) and HIP copolymer has the capability to mediate the non‐covalent assembly of nano‐fibrous HA hydrogel networks via affinity interactions with LMWH. The effect of the HIP mediation on in vitro gelation, rheological characteristics, degradation, equilibrium swelling, adipose‐derived stem cells (ASCs) proliferation and differentiation of nano‐fibrous hydrogel is examined. The results suggest the potential utility of this unique design of the bioactive nano‐fibrous HA hydrogel in directing the differentiation of ASCs and adipogenesis in ECM‐mimetic scaffolds in vitro. These studies demonstrate that this nano‐fibrous HA hydrogel can render the formulation of a therapeutically effective platform for in vitro adipogenesis applications.