Showing papers by "Beijing University of Technology published in 2009"
TL;DR: In this paper, a variety of Cu2O architectures, evolved from cubes through truncated cubes, cubooctahedrons, truncated octahedral and finally to octahedron, were achieved by simply adjusting the added PVP.
Abstract: In this work, we demonstrate the systematic and delicate geometry control of Cu2O nanocrystals by taking advantage of the selective surface stabilization effect. A variety of Cu2O architectures, evolved from cubes through truncated cubes, cubooctahedrons, truncated octahedrons and finally to octahedrons, were achieved by simply adjusting the added PVP. Based on the understanding of the intrinsic structural features of the cuprite Cu2O and PVP, we elucidated the underlying shape evolution mechanism. The as-prepared products demonstrated a crystallography-dependent adsorption ability with methyl orange (MeO) as the pollutant. With the advantage of a low cost, high yield and straightforward procedure without pre-formed crystals as sacrificial templates, this method may provide a good starting point for the study of shape construction and morphology-dependent properties of other nanocrystals.
392 citations
TL;DR: In this paper, the global ionospheric map (GIM) was used to observe variations in the total electron content (TEC) of the global positioning system (GPS) associated with 35 M ≥ 6.0 earthquakes that occurred in China during the 10-year period of 1 May 1998 to 30 April 2008.
Abstract: [1] The global ionospheric map (GIM) is used to observe variations in the total electron content (TEC) of the global positioning system (GPS) associated with 35 M ≥ 6.0 earthquakes that occurred in China during the 10-year period of 1 May 1998 to 30 April 2008. The statistical result indicates that the GPS TEC above the epicenter often pronouncedly decreases on day 3–5 before 17 M ≥ 6.3 earthquakes. The GPS TEC of the GIM and electron density profiles probed by six microsatellites of FORMOSAT3/COSMIC (F3/C) are further employed to simultaneously observe seismoionospheric anomalies during an Mw7.9 earthquake near Wenchuan, China, on 12 May 2008. It is found that GPS TEC above the forthcoming epicenter anomalously decreases in the afternoon period of day 6–4 and in the late evening period of day 3 before the earthquake, but enhances in the afternoon of day 3 before the earthquake. The spatial distributions of the anomalous and extreme reductions and enhancements indicate that the earthquake preparation area is about 1650 km and 2850 km from the epicenter in the latitudinal and longitudinal directions, respectively. The F3/C results further show that the ionospheric F2 peak electron density, NmF2, and height, hmF2, significantly decreases approximately 40% and descends about 50–80 km, respectively, when the GPS TEC anomalously reduces.
285 citations
TL;DR: An efficient quantum private comparison protocol for comparing information of equality with the help of a third party (TP) is proposed, which can ensure fairness, efficiency and security.
Abstract: Following some ideas of the quantum secret sharing (QSS) protocol (2008, Phys. Lett. A 372, 1957), we propose an efficient quantum private comparison (QPC) protocol for comparing information of equality with the help of a third party (TP). The protocol can ensure fairness, efficiency and security. The protocol is fair, which means that one party knows the sound result of the comparison if and only if the other one knows the result. The protocol is efficient with the help of the TP for calculating. However, the TP cannot learn any information about the players' respective private inputs and even about the comparison result and cannot collude with any player. The protocol is secure for the two players, that is, any information about their respective secret inputs will not leak except the final computation result. A precise proof of security of the protocol is presented. Applications of this protocol may include private bidding and auctions, secret ballot elections, commercial business, identification in a number of scenarios and so on.
285 citations
TL;DR: Wang et al. as mentioned in this paper proposed a rock mass conceptual model that identifies the effect of rock mass properties on TBM penetration rate by performing a nonlinear regression analysis, and the parametric studies of the new model showed that the rock uniaxial compressive strength and the volumetric joint count have predominantly effects on the penetration rate.
274 citations
TL;DR: In this paper, a quasi-homo buffer is introduced prior to growth of a wurtzite MgZnO epilayer to suppress phase segregation of rock-salt MgO, achieving wide range bandgap tuning from 3.3 to 4.55 eV.
Abstract: ZnO is a wide-bandgap (3.37 eV at room temperature) oxide semiconductor that is attractive for its great potential in short-wavelength optoelectronic devices, in which high quality films and heterostructures are essential for high performance. In this study, controlled growth of ZnO-based thin films and heterostructures by molecular beam epitaxy (MBE) is demonstrated on different substrates with emphasis on interface engineering. It is revealed that ultrathin AlN or MgO interfacial layers play a key role in establishing structural and chemical compatibility between ZnO and substrates. Furthermore, a quasi-homo buffer is introduced prior to growth of a wurtzite MgZnO epilayer to suppress the phase segregation of rock-salt MgO, achieving wide-range bandgap tuning from 3.3 to 4.55 eV. Finally, a visible-blind UV detector exploiting a double heterojunction of n-ZnO/insuIator-MgO/p-Si and a solar-blind UV detector using MgZnO as an active layer are fabricated by using the growth techniques discussed here.
233 citations
TL;DR: In this paper, a field investigation was carried out in the strongly affected areas and over 320 bridges were examined, and the most common damage included shear-flexural failure of the pier columns, expansion joint failure, shear key failure, and girder sliding in the transversal or longitudinal directions.
Abstract: Many highway bridges were severely damaged or completely collapsed during the 2008 Wenchuan earthquake. A field investigation was carried out in the strongly affected areas and over 320 bridges were examined. Damage to some representative highway bridges is briefly described and a preliminary analysis of the probable causes of the damage is presented in this paper. The most common damage included shear-flexural failure of the pier columns, expansion joint failure, shear key failure, and girder sliding in the transversal or longitudinal directions due to weak connections between girder and bearings. Lessons learned from this earthquake are described and recommendations related to the design of curved and skewed bridges, design of bearings and devices to prevent girder collapse, and ductility of bridge piers are presented. Suggestions for future seismic design and retrofitting techniques for bridges in moderate to severe earthquake areas are also proposed.
222 citations
TL;DR: The unique physicochemical properties associated with the copresence of 3DOM and mesoporous walls make these porous materials ideal candidates for applications in heterogeneous catalysis and CO(2) adsorption.
Abstract: Three-dimensionally (3D) ordered macroporous (3DOM) MgO, gamma-Al(2)O(3), Ce(0.6)Zr(0.4)O(2), and Ce(0.7)Zr(0.3)O(2) with polycrystalline mesoporous walls have been successfully fabricated with the triblock copolymer EO(106)PO(70)EO(106) (Pluronic F127) and regularly packed monodispersive polymethyl methacrylate (PMMA) microspheres as the template and magnesium, aluminum, cerium and zirconium nitrate(s), or aluminum isopropoxide as the metal source. The as-synthesized metal oxides were characterized by means of techniques such as X-ray diffraction (XRD), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), Fourier transform infrared (FT-IR), high-resolution scanning electron microscopy (HRSEM), high-resolution transmission electron microscopy/selected area electron diffraction (HRTEM/SAED), BET, carbon dioxide temperature-programmed desorption (CO(2)-TPD), and hydrogen temperature-programmed reduction (H(2)-TPR). It is shown that the as-fabricated MgO, gamma-Al(2)O(3), Ce(0.6)Zr(0.4)O(2), and Ce(0.7)Zr(0.3)O(2) samples possessed single-phase polycrystalline structures and displayed a 3DOM architecture; the MgO, Ce(0.6)Zr(0.4)O(2), and Ce(0.7)Zr(0.3)O(2) samples exhibited worm-hole-like mesoporous walls, whereas the gamma-Al(2)O(3) samples exhibited 3D ordered mesoporous walls. The solvent (ethanol or water) nature and concentration, metal precursor, surfactant, and drying condition have an important impact on the pore structure and surface area of the final product. The introduction of surfactant F127 to the synthesis system could significantly enhance the surface areas of the 3DOM metal oxides. With PMMA and F127 in a 40% ethanol solution, one can generate well-arrayed 3DOM MgO with a surface area of 243 m(2)/g and 3DOM Ce(0.6)Zr(0.4)O(2) with a surface area of 100 m(2)/g; with PMMA and F127 in an ethanol-HNO(3) solution, one can obtain 3DOM gamma-Al(2)O(3)with a surface area of 145 m(2)/g. The 3DOM MgO and 3DOM gamma-Al(2)O(3) samples showed excellent CO(2) adsorption behaviors, whereas the 3DOM Ce(0.6)Zr(0.4)O(2) sample exhibited exceptional low-temperature reducibility. The unique physicochemical properties associated with the copresence of 3DOM and mesoporous walls make these porous materials ideal candidates for applications in heterogeneous catalysis and CO(2) adsorption.
218 citations
TL;DR: Comparing the performance of partial nitrification via nitrite and microbial community structure were investigated and compared in two sequencing batch reactors with different dissolved oxygen (DO) levels indicated that selecting properly DO level and adopting process control method is not only of benefit to the achievement of novel biological nitrogen removal technology, but also favorable to sludge population optimization.
210 citations
TL;DR: In this article, an experimental study was carried out on a four-cylinder 1.6-L engine to explore the effect of hydrogen addition on enhancing the engine lean operating performance.
201 citations
TL;DR: It is demonstrated that the nitrite pathway could be repeatedly and reliably achieved, with over 95% of the oxidized nitrogen compounds at the end of the aerobic zone being nitrite.
191 citations
TL;DR: In this paper, high velocity oxygen fuel (HVOF) thermal spraying under different conditions was used to produce amorphous coatings with a composition of Fe(48)Cr(15),Mo(14)C(15)B(6)Y(2)
Abstract: coatings with a composition of Fe(48)Cr(15)Mo(14)C(15)B(6)Y(2) were prepared by means of high velocity oxygen fuel (HVOF) thermal spraying under different conditions. Microstructural studies show that the coatings present dense layered structure and low porosity with a fraction of nanocrystals precipitated. The porosity and fraction of the coatings decrease as the kerosene and oxygen flow increase within the parameter range examined. Corrosion behavior of the amorphous coatings was investigated by electrochemical measurement. The results show that the coatings are spontaneously passivated with wide passive region and low passive current density in 3.5% NaCl. 1 N HCl and 1 N H(2)SO(4) solutions. and exhibit an excellent ability to resist localized corrosion. However, the corrosion resistance of the coatings decreases in 1 N NaOH solution with lower transpassive potential and passive region. In addition, the optimal spraying parameter improves the corrosion resistance of the amorphous coatings obviously due to the proper proportion of porosity and amorphous fraction. (C) 2009 Elsevier B.V. All rights reserved.
TL;DR: A real-time control strategy for A(2)N-SBR can be undertaken based on some characteristic points of pH, redox potential (ORP) and dissolved oxygen (DO) profiles in order to obtain the optimum hydraulic retention time (HRT) and improve the operating reliability.
15 Aug 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the influence of erbium (Er) on the microstructure and mechanical properties of Al-Mg-Mn-Zr alloys have been investigated.
Abstract: The influences of erbium (Er) on the microstructure and mechanical properties of Al–Mg–Mn–Zr alloys have been investigated. It has been found that about 0.2 wt.% Er can be dissolved in the matrix, excess Er atoms segregate at grain boundaries to form primary Al 3 Er. Addition of 0.4 wt.% Er refines the grain size of the as-cast alloy due to the formation of primary Al 3 Er. The solid solution decomposes to form a dispersion of secondary Al 3 Er, with facets parallel to {1 0 0} and {1 1 0} planes, during homogenization at 470 °C. The secondary Al 3 Er precipitates improve strength, especially the elevated temperature strength. The yield strength, at 150 °C, of the alloy with 0.2 wt.% Er is 50% higher than that of the Er-free alloy. The recrystallization temperature of the alloy with 0.4 wt.% Er is about 25 °C higher than that of the alloy without addition of Er.
TL;DR: In this paper, the authors presented a comprehensive exergy analysis of three circuits and whole system of a ground-source heat pump (GSHP) for both building heating and cooling modes.
TL;DR: N(2)O production during nitrogen removal via nitrite decreased about 50% by applying the step-feed SBR, due to the effective control of nitrite and ammonia, the precursors of N(2]O production.
Abstract: Nitrite has been commonly recognized as an important factor causing N2O production, which weakened the advantages of nitrogen removal via nitrite. To reduce and control N2O production from wastewater treatment plants, both long-term and batch tests were carried out to investigate main sources and pathways of N2O production during nitrogen removal via nitrite from real domestic wastewater. The obtained results showed that N2O production during nitrogen removal via nitrite was 1.5 times as much as that during nitrogen removal via nitrate. It was further demonstrated that ammonia oxidization were main source of N2O production during nitrogen removal from domestic wastewater; whereas, almost no N2O was produced during nitrite oxidization and anoxic denitrification. N2O production during nitrogen removal via nitrite decreased about 50% by applying the step-feed SBR, due to the effective control of nitrite and ammonia, the precursors of N2O production. Therefore, the step-feed system is recommended as an effect...
TL;DR: Both of the tensile surface atomic-steps and the compressive buckling initiated versatile ductile plastic dislocation events and are the physical origin of the asymmetric tensile-compressive properties of postelastic instabilities and the incipient plasticity.
Abstract: Individual single-crystalline Si nanowires (NWs) were bent by forming loops or arcs with different radius. Positional-resolved atomic level strain distribution (PRALSD) along both of the radial and axial directions were calculated and mapped directly from the atomic-resolution strained high-resolution electron microscopy (HREM) images of the bent Si NWs. For the first time, the neutral-strain axis shifted from the compressive zone to the tensile region was directly demonstrated from the PRALSD along the radial direction. Bending-induced ripple-buckling of the bent Si NW was observed and a significant strain variation along the bending axial direction in the compressive region was revealed. The tensile surface atomic steps and the compressive buckling are the physical origin of the asymmetric tensile-compressive properties of postelastic instabilities and the incipient plasticity. Both of the tensile surface atomic-steps and the compressive buckling initiated versatile ductile plastic dislocation events.
TL;DR: A two-party quantum private comparison protocol using single photons, in which two distrustful parties can compare whether their secrets are equal with the help of a third party (TP), which will not be leaked out even with a compromised TP.
Abstract: We propose a two-party quantum private comparison protocol using single photons, in which two distrustful parties can compare whether their secrets are equal with the help of a third party (TP). Any information about the values of their respective secrets will not be leaked out even with a compromised TP. Security is also discussed.
TL;DR: In this article, an experimental study aimed at improving engine idle performance through hydrogen addition was carried out on a 4-cylinder gasoline-fueled spark ignited (SI) engine, which was modified to be fueled with the mixture of gasoline and hydrogen injected into the intake ports simultaneously.
TL;DR: In this paper, the three kinds of well-known bismuth molybdates α-Bi 2 Mo 3 O 12, β-bi 2 Mo 2 O 9, and γ-Bi2 MoO 6 have been prepared employing mild hydrothermal methods.
TL;DR: Monodisperse sub-2-nm EuOF nanowires were obtained by manipulating the fluorophilicity between crystalline seeds and capping surfactant molecules during the thermolysis of Eu(CF(3)COO)(3) in oleic acid (OA) and oleylamine (OM).
Abstract: Monodisperse sub-2-nm EuOF nanowires were obtained by manipulating the fluorophilicity between crystalline seeds and capping surfactant molecules during the thermolysis of Eu(CF3COO)3 in oleic acid (OA) and oleylamine (OM). The uniform EuOF nanowires can self-organize on substrates to form parallel aligned superstructures and display strong Eu3+red emissions with high quantum yields of 65% under the UV light excitations due to the presence of dense surface Eu3+ sites in the ultrathin nanowires as well as the passivation of the surface defects by the capping ligands.
TL;DR: In this paper, a magnetic-optical Fe3O4@ZnS microspheres with core−shell heterostructures have been successfully fabricated by a simple chemical deposition method.
Abstract: Bifunctional magnetic-optical Fe3O4@ZnS microspheres with core−shell heterostructures have been successfully fabricated by a simple chemical deposition method. The adsorption of sodium dodecyl sulfate (SDS) on the preformed magnetite microspheres played an essential role in directing the structure of the composites. The presented materials were characterized by FE-SEM, HRTEM, XRD, FTIR, fluorescence spectrophotometer, and SQUID MPMS. The results showed that spherical Fe3O4 cores were coated by a uniform ZnS layer. The saturation magnetization value of Fe3O4@ZnS core−shell microspheres is 52.5 emu g−1 at room temperature. Ultraviolet and visible light can be easily obtained by exposing the microspheres to different excitation wavelengths. The combined magnetic and fluorescent properties endow the microspheres with great potential applications in drug targeting, bioseparation and diagnostic analysis.
TL;DR: In this paper, the authors used the ATR-FTIR spectra and the measurements of ion exchange capacity (IEC) to better understand the differences of hydrolysis degree among the KOH, NaOH, and LiOH hydrolyzed PAN membranes.
19 May 2009
TL;DR: This work demonstrates the two routing algorithms, XY routing algorithm and Odd-Even (OE) routing algorithm, and simulates and compared based on a 3X3 mesh topology NoC with NIRGAM simulator, showing that OE routing algorithm increases P parameter greatly as compared toXY routing algorithm.
Abstract: The Network-on-Chip (NoC) has been recognized as a paradigm to solve System-on-Chip (SoC) design challenges. The routing algorithm is one of key researches of a NoC design. XY routing algorithm, which is a kind of distributed deterministic routing algorithms, is simple to be implemented. Odd-Even (OE) routing algorithm, whose implementation is complex, is a sort of distributed adaptive routing algorithms with deadlock-free ability. We demonstrate the two routing algorithms in details at first. XY routing algorithm and OE routing algorithm are then simulated and compared based on a 3X3 mesh topology NoC with NIRGAM simulator. The simulation results show that OE routing algorithm, whose P parameter equals to 1.09, increases P parameter greatly as compared to XY routing algorithm, whose P parameter equals to 0.86, in a 2-dimension 3X3 mesh topology NoC, with Constant Bit Rate (CBR) traffic condition of each tail.
TL;DR: In this article, a novel electrochemical sensor for the determination of formaldehyde is introduced based on electrodepositing nanostructured platinum-palladium alloy in Nafion film-coated glassy carbon electrode.
Abstract: A novel electrochemical sensor for the determination of formaldehyde is introduced based on electrodepositing nanostructured platinum–palladium alloy in Nafion film-coated glassy carbon electrode. Bimetallic Pt–Pd nanoparticles are found to be uniformly dispersed in Nafion film, as confirmed by scanning electron microscopic analysis. Energy dispersed X-ray analysis is used to characterize the composition of metal present in the nanoparticle-modified electrodes. The electrocatalytical behavior of the electrode is investigated by cyclic voltammetry and linear sweep voltammetry. Experimental results show that the electrode displays a remarked electrocatalytic activity for the oxidation of formaldehyde and exhibits a linear relationship in the range of 10 μM to 1 mM, with a detection limit of 3 μM in acidic solution. The low detection limit, wide linear range, and high sensitivity of the sensor make it valuable for further application.
TL;DR: When used in conjunction with MSCs as targeting vehicles in vivo, IL‐18 may offer a promising new treatment option for malignant glioma.
TL;DR: The chromia fabricated at 240 degrees C is the best among the five in catalytic performance and is because of good 3D mesoporosity and low-temperature reducibility as well as the high surface area of the chromia.
Abstract: Mesoporous chromia with ordered three-dimensional (3D) hexagonal polycrystalline structures were fabricated at 130, 180, 240, 280, and 350 °C in an autoclave through a novel solvent-free route using KIT-6 as the hard template. The as-obtained materials were characterized (by means of X-ray diffraction, transmission electron microscopy, N2 adsorption−desorption, temperature-programmed reduction, and X-ray photoelectron spectroscopy techniques) and tested as a catalyst for the complete oxidation of toluene and ethyl acetate. We found that with a high surface area of 106 m2/g and being multivalent (Cr3+, Cr5+, and Cr6+), the chromia (meso-Cr-240) fabricated at 240 °C is the best among the five in catalytic performance. According to the results of the temperature-programmed reduction and X-ray photoelectron spectroscopy investigations, it is apparent that the coexistence of multiple chromium species promotes the low-temperature reducibility of chromia. The excellent performance of meso-Cr-240 is because of go...
TL;DR: In this article, real-time aeration duration control was used to achieve efficient partial nitrification to nitrite in a sequencing batch reactor (SBR) to treat low strength domestic wastewater.
TL;DR: The study showed that real-time control strategy could prevent excess aeration and achieve stable shortcut nitrification-denitrification and nitrosation ratio (NO(2)-N/NO(x)(-)-N) higher than 96%.
TL;DR: In this paper, oriented CuS nanoplates standing perpendicularly on F: SnO 2 (FTO) coated glass substrates have been prepared through a mild microwave assisted chemical bath deposition process in which copper acetate reacted with ethylenediamine tetraacetate acid disodium and thioacetamide in aqueous solution within 40min.
TL;DR: Huang et al. as mentioned in this paper provided an approach for Chinese firms to use as a springboard to identify sources of SCA through marketing innovation, based on a cursory review of the generic literature on how to gain SCA.
Abstract: Purpose – There are different views on how to gain a sustainable competitive advantage (SCA) for firms. This topic has become an important research area in strategic management. The purpose of this paper is to provide an approach for Chinese firms to use as a springboard to identify sources of SCA through marketing innovation.Design/methodology/approach – Based on a cursory review of the generic literature on how to gain SCA, this paper considers innovation as a primary source of a firm's competitive advantage. From a practical viewpoint, marketing innovation is identified as a significant source of SCA, especially for those firms operating in the dynamic and competitive Chinese economic environment. Through an analysis of marketing innovations at the Huawei Technologies Co. Ltd in China, an approach is developed to help managers identify their unique sources of SCA through marketing innovation.Findings – This study reveals marketing innovation results from a considered analysis of the various marketing f...