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31.
Haitang?Yang Bingyue?Li Rongjing?Cui Ruimin?XingEmail author Shanhu?LiuEmail author 《Journal of nanoparticle research》2017,19(10):354
The key step in the fabrication of highly active electrochemical sensors is seeking multifunctional nanocomposites as electrode modified materials. In this study, the gold nanoparticle-decorated helical carbon nanotube nanocomposites (AuNPs-HCNTs) were fabricated for rutin detection because of its superior sensitivity, the chemical stability of AuNPs, and the superior conductivity and unique 3D–helical structure of helical carbon nanotubes. Results showed the prepared nanocomposites exhibited superior electrocatalytic activity towards rutin due to the synergetic effects of AuNPs and HCNTs. Under the optimized conditions, the developed sensor exhibited a linear response range from 0.1 to 31 μmol/L for rutin with a low detectable limit of 81 nmol/L. The proposed method might offer a possibility for electrochemical analysis of rutin in Chinese medical analysis or serum monitoring owing to its low cost, simplicity, high sensitivity, good stability, and few interferences against common coexisting ions in real samples. 相似文献
32.
33.
The acoustic wave propagation from a two-dimensional subwavelength slit surrounded by metal plates decorated with Helmholtz resonators(HRs) is investigated both numerically and experimentally in this work. Owing to the presence of HRs, the effective impedance of metal surface boundary can be manipulated. By optimizing the distribution of HRs,the asymmetric effective impedance boundary will be obtained, which contributes to generating tunable acoustic radiation pattern such as directional acoustic beaming. These dipole-like radiation patterns have high radiation efficiency, no fingerprint of sidelobes, and a wide tunable range of the radiation pattern directivity angle which can be steered by the spatial displacements of HRs. 相似文献
34.
We provide the combined wave number eigenvalue equations (CWNEE) method based upon the plane-wave expansion (PWE) method to calculate and optimize the band structures of the two-dimension (2D) photonic crystals (PhCs). Compared with the traditional PWE methods for the metal PhCs, the band structures can be obtained directly using the CWNEE method, and not any extra procedures are needed to handle the folded band structures. The comparison between the CWNEE method and FDTD method in accuracy and time-consuming has been analyzed, and the results show that the CWNEE method is reliable and accurate. With the CWNEE method and the Bisection-Particle Swarm Optimization method, we optimize the large gap–midgap ratio of the 2D square lattice of square metal rods and circular metal rods. Unlike many traditional PWE method, the CWNEE method can directly calculate the band structure in the arbitrary given frequency range, and it is quite useful for calculating the defect mode of photonic crystal cavity. 相似文献
35.
Exchange coupling and helical spin order in the triangular lattice antiferromagnet CuCrO<sub>2</sub> using first principles
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The magnetic and electronic properties of the geometrically frustrated triangular antiferromagnet CuCrO2 are investigated by first principles through density functional theory calculations within the generalized gradient approximations (GGA)+U scheme. The spin exchange interactions up to the third nearest neighbours in the ab plane as well as the coupling between adjacent layers are calculated to examine the magnetism and spin frustration. It is found that CuCrO2 has a natural two-dimensional characteristic of the magnetic interaction. Using Monte-Carlo simulation, we obtain the Neel temperature to be 29.9 K, which accords well with the experimental value of 24 K. Based on non-collinear magnetic structure calculations, we verify that the incommensurate spiral-spin structure with (110) spiral plane is believable for the magnetic ground state, which is consistent with the experimental observations. Due to intra-layer geometric spin frustration, parallel helical-spin chains arise along the a, b, or a + b directions, each with a screw-rotation angle of about 120°. Our calculations of the density of states show that the spin frustration plays an important role in the change of d-p hybridization, while the spin-orbit coupling has a very limited influence on the electronic structure. 相似文献
36.
In this paper, we mainly study the generalized Heisenberg-Virasoro algebra. Some structural properties of the Lie algebra
are obtained.
相似文献
37.
It is shown that the cortical brain network of the macaque
displays a hierarchically clustered organization and the neuron
network shows small-world properties. Now the two factors will be
considered in our model and the dynamical behavior of the model
will be studied. We study the characters of the model and find
that the distribution of avalanche size of the model follows
power-law behavior. 相似文献
38.
《Nuclear Physics B》2001,609(3):499-517
We analyze the propagation of a scalar field in multidimensional theories which include kinetic corrections in the brane, as a prototype for gravitational interactions in a four-dimensional brane located in a (nearly) flat extra-dimensional bulk. We regularize the theory by introducing an infrared cutoff given by the size of the extra dimensions, R, and a physical ultraviolet cutoff of the order of the fundamental Planck scale in the higher-dimensional theory, M. We show that, having implemented cutoffs, the radius of the extra dimensions cannot be arbitrarily large for M≳1 TeV. Moreover, for finite radii, the gravitational effects localized on the brane can substantially alter the phenomenology of collider and/or table-top gravitational experiments. This phenomenology is dictated by the presence of a massless graviton, with standard couplings to the matter fields, and a massive graviton which couples to matter in a much stronger way. While graviton KK modes lighter than the massive graviton couple to matter in a standard way, the couplings to matter of the heavier KK modes are strongly suppressed. 相似文献
39.
Long-range effects on the pyroelectric coefficient of a ferroelectric superlattice consisting of two different ferroelectric materials are investigated based on the transverse Ising model.The effects of the interfacial coupling and the thickness of one period on the pyroelectric coefficient of the ferroelectric superlattics are studied by taking into account the long-range interaction.It is found that with the increase of the strength of the long-range interaction,the pyroelectric coefficient decreases when the temperature is lower than the phase transition temperature;the mumber of the pyroelectric peaks decreases gradually and the phase transition temperature increases,It is also found that with the decrease of the interfacial coupling and the thickness of one period.the phase transition temperature and the number of the pyroelectric peaks decrease. 相似文献
40.
将油性剂油酸(OA)填充进多壁碳纳米管(MWCNTs)的空腔内制备复合物,再以复合物为添加剂制备一种纳米流体,考察了复合物的质量分数、MWCNTs的酸处理时间以及摩擦测试条件等对纳米流体摩擦学性能的影响,并分析了复合物的润滑机理. 结果表明:油酸被成功填充到经酸处理的MWCNTs管内,填充率约20%;摩擦过程中,复合物制备的纳米流体的摩擦系数有不断减小趋势,其减摩效果甚至优于同等含量的油酸乳化液;当复合物的质量分数为0.1%左右时,纳米流体可获得最佳的减摩、抗磨效果;随着酸化处理时间的增加,复合物制备的纳米流体的减摩、抗磨性能会有所提高. 摩擦过程中,复合物可释放出油酸并形成润滑膜,MWCNTs则能够在油酸形成的润滑膜上发挥“微轴承”的作用,从而使复合物获得更加优良的减摩、抗磨效果. 相似文献