Multifunctional carbon-coated magnetic sensing graphene oxide-cyclodextrin nanohybrid for potential cancer theranosis

Journal of Nanoparticle Research - Over the last years, an environmentally friendly and economically efficient way of nanoparticle production has been found in the biosynthesis of metal...     

Recommendation in evolving online networks

Recommender system is an effective tool to find the most relevant information for onlineusers. By analyzing the historical selection records of users, recommender system predictsthe most likely future links in the user-item network and accordingly constructs apersonalized recommendation list for each user. So far, the recommendation process ismostly investigated in static user-item networks. In this paper, we propose a model whichallows us to examine the performance of the state-of-the-art recommendation algorithms inevolving networks. We find that the recommendation accuracy in general decreases with timeif the evolution of the online network fully depends on the recommendation. Interestingly,some randomness in users’ choice can significantly improve the long-term accuracy of therecommendation algorithm. When a hybrid recommendation algorithm is applied, we find thatthe optimal parameter gradually shifts towards the diversity-favoring recommendationalgorithm, indicating that recommendation diversity is essential to keep a high long-termrecommendation accuracy. Finally, we confirm our conclusions by studying therecommendation on networks with the real evolution data.     

Electron acceleration using two crossed Bessel beams in vacuum

The direct acceleration of electrons by using two crossed linearly polarized Bessel beams with equal frequency and amplitude in vacuum is studied and compared with the case of single linearly polarized Bessel beam. It is found that two zeroth- and first-order Bessel beams with π-rad phase difference have a nonvanishing longitudinal electric field on the z-axis, which can be maximized under certain conditions and used to accelerate electrons. Two crossed zeroth- and first-order Bessel beams have a larger maximum longitudinal electric field on the z-axis than that of a single first-order Bessel beam, and are suited for laser electron acceleration.     

Multifractal analysis of the Yellow River flows

This paper deals with time series of the Yellow River daily flows at Tongguan hydrological station, from the year 2000 to 2005. Power spectrum analysis and statistical moment scaling function on a range of scales revealed scaling qualities of the data. The partition function, which displayed a convex curvature, and the generalized dimension function showed that multifractality is presented. The singularity spectrum, which is single-humped, has shown strong multifractality degree.     

传输同步辐射X射线的锥形单毛细管的物理特性

根据北京同步辐射装置生物大分子实验站(2W1A)的条件和应用,从理论上研究了锥形单毛细管传输同步辐射X射线的物理特性.计算了锥管传输效率随锥管长度、X射线能量的变化规律;计算了锥管出口处的光强分布,强度增益随工作距离的变化规律.结果表明:与传输发散X射线相比,锥形单毛细管传输平行X射线的物理特性有明显的不同.     

Fluorescence switch of dye-infiltrated SiO<Subscript>2</Subscript> inverse opal based on acid-base vapors or light

The acid-base vapors/light double responsive dye-infiltrated SiO₂ inverse opal photonic crystals (PCs) were fabricated by sacrificial template method and a subsequent infiltration of spiropyran derivative dye molecules. The fluorescence of ring-open dye molecules infiltrated in PCs can be switched on/off based on different fluorescence properties of spiropyran dye under stimuli of acid-base vapors or light, when PCs with suitable stopband were selected. The fluorescence switch behavior based on PCs has potential applications in data storage, color displays, chemical and biological sensors.     

First principles study of the electronic properties of twinned SiC nanowires

The electronic properties of saturated and unsaturated twinned SiC nanowires grown along [111] direction and surrounded by {111} facets are investigated using first-principles calculations with density functional theory and generalized gradient approximation. All the nanowires considered, including saturated and unsaturated ones, exhibit semiconducting characteristics. The saturated nanowires have a direct band gap and the band gap decreases with increasing diameters of the nanowires. The hexagonal (2H) stacking inside the cubic (3C) stacking has no effect on electronic properties of the SiC nanowires. The highest occupied molecular orbitals and the lowest unoccupied molecular orbitals are distributed along the nanowire axis uniformly, which indicates that the twinned SiC nanowires are good candidates in realizing nano-optoelectronic devices.     

Shape identification using phase shifting interferometry and liquid-crystal phase modulator

A phase shifting technique using a Michelson interferometry system is presented and applied to surface contour measurement. Hyperbolic fringes are produced by the interference of two spherical wavefronts expanded from a beam expander. The fringe pattern is projected on an object surface and the deformed grating image is captured by a CCD camera for subsequent analysis by a PC. Phase variation is achieved by a liquid-crystal device incorporated in the Michelson interferometry system. Results obtained using the proposed method for objects of various shapes and sizes compared well with those from a conventional profilometer.     

The nonlinear optical response of a fluorine-containing azoic dye

The nonlinear optical nonlinearities of a fluorine-containing azoic dye in tetrahydrofuran have been investigated by using Z-scan technique with picosecond and nanosecond lasers. The experimental results reveal that the azoic dye has large optical nonlinearity under the excitations of picosecond and nanosecond 532 nm. At the picosecond 532 nm the solution presents negative nonlinear refraction due to the electronic effect, while the larger nonlinear refraction under nanosecond laser excitation is induced by thermal effect. Moreover, the different nonlinear absorption behavior under picosecond and nanosecond excitations is analyzed.     

Soliton squeezing generated in an all-fiber configuration

We experimentally demonstrate amplitude squeezed soliton utilizing intensity-dependent self-phase modulation in an asymmetric Sagnac interferometer. The system, whose components are connected via ferrule connector/physical connection （FC/PC） fiber connectors, constitutes all-fiber configuration to generate squeezed soliton. Soliton amplitude reduction measured by homodyne detection is near 4.0 dB below the shot-noise level. Optimal squeezing fields in both simple and compact all-fiber configuration are obtained.