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Search Results: 1 - 10 of 36532 matches for " Xiao Xiangheng "
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Preparation and characterization of spindle-like Fe3O4 mesoporous nanoparticles
Zhang Shaofeng,Wu Wei,Xiao Xiangheng,Zhou Juan
Nanoscale Research Letters , 2011,
Abstract: Magnetic spindle-like Fe3O4 mesoporous nanoparticles with a length of 200 nm and diameter of 60 nm were successfully synthesized by reducing the spindle-like α-Fe2O3 NPs which were prepared by forced hydrolysis method. The obtained samples were characterized by transmission electron microscopy, powder X-ray diffraction, attenuated total reflection fourier transform infrared spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and nitrogen adsorption-desorption analysis techniques. The results show that α-Fe2O3 phase transformed into Fe3O4 phase after annealing in hydrogen atmosphere at 350°C. The as-prepared spindle-like Fe3O4 mesoporous NPs possess high Brunauer-Emmett-Teller (BET) surface area up to ca. 7.9 m2 g-1. In addition, the Fe3O4 NPs present higher saturation magnetization (85.2 emu g-1) and excellent magnetic response behaviors, which have great potential applications in magnetic separation technology.
Facile method to synthesize magnetic iron oxides/TiO2 hybrid nanoparticles and their photodegradation application of methylene blue
Wu Wei,Xiao Xiangheng,Zhang Shaofeng,Ren Feng
Nanoscale Research Letters , 2011,
Abstract: Many methods have been reported to improving the photocatalytic efficiency of organic pollutant and their reliable applications. In this work, we propose a facile pathway to prepare three different types of magnetic iron oxides/TiO2 hybrid nanoparticles (NPs) by seed-mediated method. The hybrid NPs are composed of spindle, hollow, and ultrafine iron oxide NPs as seeds and 3-aminopropyltriethyloxysilane as linker between the magnetic cores and TiO2 layers, respectively. The composite structure and the presence of the iron oxide and titania phase have been confirmed by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectra. The hybrid NPs show good magnetic response, which can get together under an external applied magnetic field and hence they should become promising magnetic recovery catalysts (MRCs). Photocatalytic ability examination of the magnetic hybrid NPs was carried out in methylene blue (MB) solutions illuminated under Hg light in a photochemical reactor. About 50% to 60% of MB was decomposed in 90 min in the presence of magnetic hybrid NPs. The synthesized magnetic hybrid NPs display high photocatalytic efficiency and will find recoverable potential applications in cleaning polluted water with the help of magnetic separation.
Facile Fabrication of Ultrafine Hollow Silica and Magnetic Hollow Silica Nanoparticles by a Dual-Templating Approach
Wu Wei,Xiao Xiangheng,Zhang Shaofeng,Fan Lixia
Nanoscale Research Letters , 2009,
Abstract: The development of synthetic process for hollow silica materials is an issue of considerable topical interest. While a number of chemical routes are available and are extensively used, the diameter of hollow silica often large than 50 nm. Here, we report on a facial route to synthesis ultrafine hollow silica nanoparticles (the diameter of ca. 24 nm) with high surface area by using cetyltrimethylammmonium bromide (CTAB) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as co-templates and subsequent annealing treatment. When the hollow magnetite nanoparticles were introduced into the reaction, the ultrafine magnetic hollow silica nanoparticles with the diameter of ca. 32 nm were obtained correspondingly. Transmission electron microscopy studies confirm that the nanoparticles are composed of amorphous silica and that the majority of them are hollow.
One-Pot Reaction and Subsequent Annealing to Synthesis Hollow Spherical Magnetite and Maghemite Nanocages
Wu Wei,Xiao Xiangheng,Zhang Shaofeng,Li Hang
Nanoscale Research Letters , 2009,
Abstract: Water-soluble hollow spherical magnetite (Fe3O4) nanocages (ca.100 nm) with high saturation magnetization are prepared in a one-pot reaction by sol-gel method and subsequent annealing to synthesise the maghemite (γ-Fe2O3) nanocages with similar nanostructures. The nanocages have been investigated by powder X-ray diffraction (XRD), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), and superconducting quantum interference device (SQUID). The results indicated that glutamic acid played an important role in the formation of the cage-like nanostructures.
Adaptive Dynamic Power Management Policy: Two Value Alternate Basis
Yan Wang,Xiangheng Shen
Research Journal of Applied Sciences, Engineering and Technology , 2013,
Abstract: In dynamic power management, fixed time-out policy is not optimal because of waiting before shutting down a component and adaptive time-out policy is instability for re-choosing parameters for different workloads. To handle these problems, a new adaptive time-out policy is proposed in this study. Combining the advantage of fixed and adaptive time-out policy zero and spin-down cost are chosen as time-out values in the policy. They alternate as time-out values according history workloads. Zero as one of time-out makes for saving more power. And spin-down cost which only depends on disk model causes policy has more steady performance. Policy based on tow values sufficiently uses the character of cluster and bursty of workloads. Simulation results show that policy proposed in this study is approach to optimal policy and performs more steadily.
The thickness of amalgamations of graphs
Yan Yang,Xiangheng Kong
Mathematics , 2012,
Abstract: The thickness $\theta(G)$ of a graph $G$ is the minimum number of planar spanning subgraphs into which the graph $G$ can be decomposed. As a topological invariant of a graph, it is a measurement of the closeness to planarity of a graph, and it also has important applications to VLSI design. In this paper, the thickness of graphs that are obtained by vertex-amalgamation and bar-amalgamation of any two graphs whose thicknesses are known are obtained, respectively. And the lower and upper bounds for the thickness of graphs that are obtained by edge-amalgamation and 2-vertex-amalgamation of any two graphs whose thicknesses are known are also derived, respectively.
Efficiency enhancements in Ag nanoparticles-SiO2-TiO2 sandwiched structure via plasmonic effect-enhanced light capturing
Jinxia Xu,, Xiangheng Xiao,, Andrey L Stepanov, Fen Ren,, Wei Wu, Guangxu Cai, Shaofeng Zhang, Zhigao Dai, Fei Mei and Changzhong Jiang
Nanoscale Research Letters , 2013, DOI: 10.1186/1556-276X-8-73
Abstract: TiO2-SiO2-Ag composites are fabricated by depositing TiO2 films on silica substrates embedded with Ag nanoparticles. Enhancement of light absorption of the nanostructural composites is observed. The light absorption enhancement of the synthesized structure in comparison to TiO2 originated from the near-field enhancement caused by the plasmonic effect of Ag nanoparticles, which can be demonstrated by the optical absorption spectra, Raman scattering investigation, and the increase of the photocatalytic activity. The embedded Ag nanoparticles are formed by ion implantation, which effectively prevents Ag to be oxidized through direct contact with TiO2. The suggested incorporation of plasmonic nanostructures shows a great potential application in a highly efficient photocatalyst and ultra-thin solar cell.
Microbial Fuel Cells for Nitrate Removal in Ground Water  [PDF]
Xiao Xiao, Kangping Cui
Advances in Microbiology (AiM) , 2015, DOI: 10.4236/aim.2015.56044
Abstract: The increasing nitrate concentration in groundwater has become a serious concern all over the world. In this study, the double chamber microbial fuel cell (MFC) and single chamber MFC systems were proposed for simultaneous removal of chemical oxygen demand (COD) and nitrate (NO3- - N). Transforming the various variables (cathod materials, external resistance and initial concentrations of NO3- - N) of double chamber MFC to determine the optimal operating parameters. Observing the treatment effect of single chamber MFC when adding an external resistance. The results showed: in the case of connecting external circuit, the double chamber MFC could reach the best degradation effect of NO3- - N and COD when cathode and anode materials are made of stainless steel velvet, the external resistance of 100 Ω and the initial concentrations of NO3- - N of around 250 mg/L. The best degradation rate of NO3- - N and COD reached 66.88% and 82.85% respectively. Adding an external solar power to single chamber could enhance the treatment effect; specifically, NO3- - N and COD removal rate reached 65.06% and 70.42% respectively, 6.14% and 9.73% higher than without external power.
Study on the Strategy of Building Shanghai into an International Financial Centre  [PDF]
Zhirun Xiao, Zhirun Xiao
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.37032
Abstract:

If china wants to become a financial and economic powerhouse, it has to possess a world-class financial centre. So, it has the particular importance of practical significance to build Shanghai into international financial centre. It is also a research subject having far-reaching influence. This article introduces the background of building Shanghai into international financial centre and illuminates the strategic target and thinking of building Shanghai into international financial centre. And the author analyzes and studies the question of strategic choice of building Shanghai into international financial centre.

The Impact of the American English Learning upon Chinese College Students’ Ideology  [PDF]
Xiao Yue
Creative Education (CE) , 2012, DOI: 10.4236/ce.2012.31026
Abstract: In recent decades, many researchers have devoted themselves to the study of the impact of American ideology upon Chinese college students. However, few of researches have been made in this area in view of language attrition. This thesis mainly analyses the transfer of Chinese college students’ ideology caused by the language attrition during the process of American English learning, such as the regression of Chinese language in different degrees and the decline of self-identities in Chinese culture. The transfer of ideology is manifested in the aspects of Chinese college students’ ideas, values, self-identities, etc. This thesis also provides evidence for the current situations that Chinese college students’ ideology was transferred by the first language attrition. Language attrition is a method different from other traditional research methods, and it is a whole new point of view at a cultural level.
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