Showing papers by "University of Science and Technology Beijing published in 2009"
TL;DR: Zhang et al. as discussed by the authors proposed a method for the detection of defects in materials based on the properties of materials and their properties in terms of their properties and properties of properties.
Abstract: [*] Prof. Y. Zhang, X. M. Zhang Department of Materials Physics and Chemistry State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 (PR China) E-mail: yuezhang@ustb.edu.cn Prof. Z. L. Wang, X. M. Zhang, M. Y. Lu School of Materials Science and Engineering Georgia Institute of Technology Atlanta, Georgia 30332-0245, (USA) E-mail: zhong.wang@mse.gatech.edu Prof. L. J. Chen, M. Y. Lu Department of Materials Science and Engineering National Tsing Hua University Hsinchu, Taiwan 30043, (ROC)
432 citations
TL;DR: Investigation of the distribution and accumulation of SNPs in rats with subcutaneous injection indicated that SNPs translocated to the blood circulation and distributed throughout the main organs, especially in the kidney, liver, spleen, brain and lung in the form of particles.
Abstract: Silver nanoparticles (SNPs) are widely used in the field of biomedicine, but a comprehensive understanding of how SNPs distribute in the body and the induced toxicity remains largely unknown. The present study was designed to investigate the distribution and accumulation of SNPs in rats with subcutaneous injection. Rats were injected with either SNPs or silver microparticles (SMPs) at 62.8 mg/kg, and then sacrificed at predetermined time points. The main organs of the experimental animals were harvested for ultrastructural analysis by transmission electron microscopy (TEM) and for silver content analysis by inductively coupled plasma mass spectrometry (ICP-MS). Results indicated that SNPs translocated to the blood circulation and distributed throughout the main organs, especially in the kidney, liver, spleen, brain and lung in the form of particles. SMPs, however, could not invade the blood stream, or organ tissues. Ultrastructural observations indicate that those SNPs that had accumulated in organs could enter different kinds of cells, such as renal tubular epithelial cells and hepatic cells. Moreover, SNPs also induced blood-brain barrier (BBB) destruction and astrocyte swelling, and caused neuronal degeneration. The results suggest more cautions needed in biomedical applications of SNPs, in particular, the long-term uses.
362 citations
TL;DR: In this paper, the authors investigated the hydrogen-induced cracking behavior of X100 pipeline steel by a combination of tensile test, electrochemical hydrogen permeation measurement and surface characterization techniques.
261 citations
TL;DR: In this article, a methodology is proposed for predicting the effective thermal conductivity of dilute suspensions of nanoparticles (nanofluids) based on rheology, which uses the rheological data to infer microstructures of nanarticles quantitatively, which is then incorporated into the conventional Hamilton-Crosser equation to predict the effective TCE of nanofluid.
247 citations
TL;DR: An up-flow anaerobic sludge blanket reactor-microbial fuel cell-biological aerated filter-MFC-BAF system was developed for simultaneous bioelectricity generation and molasses wastewater treatment in this study.
243 citations
20 Aug 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a microtexture analysis performed with the EBSD technique of new grains formed at compression twins in the early stage of static recrystallization of hexagonal magnesium alloy AZ31 was performed.
Abstract: In contrast to cubic metals, the dominant recrystallization nucleation site of hexagonal magnesium is compression twins or the shear bands evolved from them. In this paper, we determine the macrotextures and microstructures of a magnesium alloy AZ31 during static recrystallization. We interpret these data according to a microtexture analysis performed with the EBSD technique of new grains formed at compression twins in the early stage of static recrystallization. The results show that the orientation characteristics in local regions during nucleation are similar to those of subgrains within compression twins or shear bands. However, the new grains mainly take the orientations of the subgrains, which have been subjected to complicated orientation rotations. This phenomenon is attributed to the large amount of their stored energy. Despite the difference between new grain orientations and those of the deformed matrix, the retained deformation texture after annealing is explained mainly by the incomplete recrystalization of magnesium.
186 citations
12 Dec 2009
TL;DR: A hierarchy of P2P reputation systems is suggested to protect clouds and datacenters at the site level and to safeguard the data objects at the file-access level to protect cloud service models, currently implemented by Amazon, IBM, and Google.
Abstract: Internet clouds work as service factories built around web-scale datacenters. The elastic cloud resources and huge datasets processed are subject to security breaches, privacy abuses, and copyright violations. Provisioned cloud resources on-demand are especially vulnerable to cyber attacks. The cloud platforms built by Google, IBM, and Amazon all reveal this weaknesses. We propose a new approach to integrating virtual clusters, security-reinforced datacenters, and trusted data accesses guided by reputation systems. A hierarchy of P2P reputation systems is suggested to protect clouds and datacenters at the site level and to safeguard the data objects at the file-access level. Different security countermeasures are suggested to protect cloud service models: IaaS, PaaS, and SaaS, currently implemented by Amazon, IBM, and Google, respectively.
178 citations
TL;DR: Ultrasound-assisted ionic liquid dispersive liquid-phase micro-extraction was developed for the determination of four aromatic amines and has been found to have excellent detection sensitivity with limits of detection.
175 citations
173 citations
TL;DR: In this article, a salt fog test and an outdoor test of low-alloy steels (A and B) with different carbon content was performed by a commercial weathering steel 09CuPCrNi and showed that homogeneous microstructures, proper amounts of carbon content and fine carbon-rich phases are beneficial for the corrosion resistance of steels.
153 citations
TL;DR: It was found that localized amorphization of single-crystal boron carbide takes place during unloading from high pressures, and nonhydrostatic stresses play a critical role in the high-pressure phase transition.
Abstract: We report depressurization amorphization of single-crystal boron carbide (B4C) investigated by in situ high-pressure Raman spectroscopy. It was found that localized amorphization of B4C takes place during unloading from high pressures, and nonhydrostatic stresses play a critical role in the high-pressure phase transition. First-principles molecular dynamics simulations reveal that the depressurization amorphization results from pressure-induced irreversible bending of C-B-C atomic chains cross-linking 12 atom icosahedra at the rhombohedral vertices.
TL;DR: This paper investigates the global stability of virus dynamics model with Beddington–DeAngelis infection rate by constructing Lyapunov functions, and finds that the steady states are always globally asymptotically stable for Holling type II functional response or for a saturation response.
TL;DR: In this article, a microstructural study revealed that the titanium carbide particles were distributed uniformly in the matrix phase and no interface debonding and micro-cracks were observed in the composite.
TL;DR: In this article, the phase structure of face centered cubic transits to body centered cubic (BCC), namely from a structure with high atomic packing efficiency (APE) to a lower one, and compressive strength increases from 1650 MPa to 2697 MPa.
TL;DR: In this article, the effect of inclusions on the initiation of stress corrosion cracking (SCC) X70 pipeline steel was investigated in an acidic soil solution using slow strain rate test, scanning electron microscopy and energy-dispersive X-ray techniques.
TL;DR: In this article, the size effects on the microstructure and mechanical behaviors of a high entropy alloy of AlCoCrFeNi was studied by preparing as-cast rod samples with different diameters.
Abstract: High entropy alloys are usually defined as the kind of alloys with at least five principle components, each component has the equi-atomic ratio or near equi-atomic ratio, and the high entropy alloys can have very high entropy of mixing, forming simple solid solution rather than many complex intermediate phases. In this paper, the size effects on the microstructure and mechanical behaviors of a high entropy alloy of AlCoCrFeNi was studied by preparing as-cast rod samples with different diameters. The alloy independent of cast diameter samples has the same phase of body centered cubic solid solution. With decreasing casting diameter, both the strength and the plasticity are increased slightly.
TL;DR: In this paper, a test rig was developed to study the effect of cathodic protection (CP) on corrosion of X70 pipeline steel in the crevice area under disbonded coating through the measurements of local potential, solution pH and dissolved oxygen concentration.
TL;DR: In this article, a local additional potential model (LAPM) was developed to illustrate the critical role of strain rate in SCC of X70 pipeline steel in an acidic soil solution was investigated by slow strain rate test, surface characterization, potentiodynamic polarization curve measurement and electrochemical hydrogen permeation technique.
TL;DR: In this paper, N-type thermoelectric materials were firstly prepared by spark plasma sintering (SPS) using mechanically alloyed powders and then annealed at 423-593k for 10-144h.
TL;DR: In this article, the effects of La-and Co-doping into perovskite oxides on their phase structure, electrical conductivity, ionic conductivity and oxygen vacancy concentration have been investigated.
TL;DR: In this article, a novel process has been investigated using microbial fuel cells (MFCs) by employing sulfide, organics and vanadium(V) as electron donors and acceptor, respectively.
Abstract: BACKGROUND: Sulfide-containing wastewater (also containing organics) and vanadium(V)-containing wastewater exist widely and can be treated in microbial fuel cells (MFCs) based on their chemical conditions. A novel process has been investigated using MFC technologies by employing sulfide, organics and V(V) as electron donors and acceptor, respectively.
RESULTS: Electrons produced by oxidation of sulfide and organics in the anode compartment were transferred to the anode surface, then flowed to the cathode through an external circuit, where they were consumed to reduce V(V). Sulfide and total organics removal approached 84.7 ± 2.8% and 20.7 ± 2.1%, with a V(V) reduction rate of 25.3 ± 1.1%. The maximum power output obtained was 572.4 ± 18.2 mW m−2. The effects of the microbes on electricity generation as well as the products of sulfide oxidation and V(V) reduction were also evaluated and analyzed.
CONCLUSION: This process achieves both sulfide and V(V) removal with electricity generation simultaneously, providing an economical route for treating these kinds of wastewaters. Copyright © 2009 Society of Chemical Industry
TL;DR: The present result appears to add new members to the very few examples of polynuclear clusters exhibiting 3D magnetic ordering relying on intermolecular interactions, to the best of the knowledge, which will be helpful for providing valuable information for the understanding and application of intermolescular hydrogen-bonding interactions in the molecular magnetic materials.
Abstract: A series of six new cyanide-bridged heterometallic complexes including two tetranuclear T-like FeIIIMnIII3 compounds, {[Mn(L1)(H2O)]3[Fe(CN)5(1-CH3im)]}ClO4·1.5H2O (1) and {[Mn(L2)(H2O)]3[Fe(CN)5(1-CH3im)]}ClO4·3H2O (2); two heptanuclear cage-shaped MIIIMnIII6 (M = Fe, Cr) compounds, {[Mn(L2)(H2O)]6[Fe(CN)6]}[Fe(CN)6]·6CH3OH (3) and {[Mn(L2)(H2O)]6[Cr(CN)6]}[Cr(CN)6]·6CH3OH (4); and two two-dimensional M−MnIII networks, {[H3O][Mn(L1)]2[Fe(CN)6]}·2DMF (5) and {K[Mn(L1)]2[Cr(CN)6]}·1.5CH3CN·CH3OH (6) (L1 = N,N-ethylene-bis(3-methoxysalicylideneiminate, L2 = N,N-ethylene-bis(3-ethoxysalicylideneiminate) have been successfully assembled from three polycyanidemetalates containing five or six cyanide groups and two manganese(III) building blocks containing bicompartmental Schiff base ligands. The cyanide-bridged polynuclear complexes are self-complementary through a coordinated aqua ligand from one complex and the free O4 compartment from the neighboring complex, giving supramolecular one-dimensional ladders an...
TL;DR: In this paper, a large-scale, well-aligned single crystalline TiO-sub 2 nanorod arrays were prepared on the pre-treated glass substrate by a hydrothermal approach.
TL;DR: In this article, the evolution of Y 2 O 3 during mechanical alloying and subsequent annealing was studied with the main focus on the refinement of particle size by the addition of minor alloying elements.
TL;DR: In this article, the effects of Fe2O3 on the pyrolysis reactivity of demineralized anthracite were investigated by a thermogravimetric analyzer.
Abstract: Effects of Fe2O3 on the pyrolysis reactivity of demineralized anthracite were investigated by a thermogravimetric analyzer, indicating that pyrolysis reactivity of Fe2O3 loaded demineralized anthracite was higher than that of raw demineralized anthracite when temperature is over 500 degrees C, Chars were prepared from the two coal samples in muffle with heating progress, and their structures were analyzed using SEM, FTIR, XRD, and Raman. FTIR results showed that absorption peaks of functional groups on the surface of char from catalytic pyrolysis at 700 T were more than that of char from noncatalytic pyrolysis. Raman results demonstrated values Of (I-D3 + I-D4)/I-G,I- of chars from catalytic pyrolysis and noncatalytic pyrolysis were 4.76 and 3.86, respectively, indicating that ordering of the char was decreased by Fe2O3. XRD analysis revealed that diffraction angle of the 002 peak did not shift; however, 1,,, and 4, decreased, indicating degree of graphitization for microcrystalline structure of char from catalytic pyrolysis was decreased, The results of FTIR, XRD, and Raman of the chat, showed that catalytic pyrolysis improved the formation of free radicals, while hindered polymerization and forming of basic structure units. Finally, combustion reactivity of the three chars, including char of raw demineralized anthracite (char-A), char Of Fe2O3-loaded demineralized anthracite (char-B), and char. Of Fe2O3-loaded demineralized anthracite washed by HCl (char-C), was investigated using TG and indicated that their active order was char-B > char- C > char-A, The results corroborated that Fe2O3 changed structure of anthracite char and improved combustion reactivity.
TL;DR: In this article, Ab initio molecular dynamics calculations were performed on the atomic configuration of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass and the local structures were characterized in terms of structure factors (SF), pair correlation functions (PCF), coordinate numbers, bond pairs and Voronoi polyhedra.
TL;DR: Photophysical studies indicate that all of the complexes exhibit luminescence both in solution and in solid sate, and there exists an energy transfer from the [Zn(L)Cl](-) unit to the central rare earth ions of Nd(III) (5 and 6), Tb(III).
Abstract: A series of phenoxo-bridged heterometallic Schiff-base trinuclear complexes Zn-M-Zn [M = Cd(II), Pb(II), Nd(III), Eu(III), Gd(III), Tb(III), and Dy(III)] have been synthesized by a rational structural design based on two symmetrical Schiff-base ligands N,N'-bis(3-methoxysalicylidene)propylene-1,3-diamine (H(2)L(a)) and N,N'-bis(3-methoxysalicylidene)benzene-1,2-diamine (H(2)L(b)). Single X-ray diffraction analysis reveals a similar molecular structure among the eight propeller-like and seven sandwich-type phenoxo-bridged Zn-M-Zn complexes. In the compounds Cd[Zn(L(a))Cl](2) (1), {Cd[Zn(L(b))Cl](2)}.H(2)O (2), {Pb[Zn(L(b))Cl](2)}.2H(2)O (4), {Nd[Zn(L(a))Cl](2)(H(2)O)}.0.5ZnCl(4) .2H(2)O (5), and{M(III)[Zn(L(a))Cl](2)(H(2)O)}.0.5ZnCl(4).2MeOH [M = Eu(7), Gd (9), Tb (11), and Dy (13)], two [Zn(L)Cl](-) units coordinate to the central metal ion as a tetradentate ligand using its four oxygen atoms, forming a two-blade propeller-like left-handed and right-handed chiral Zn-M-Zn configuration despite the racemic nature of the whole complexes. Compounds {Pb[Zn(L(a))Cl](2)}.MeOH (3), {Nd[Zn(L(b))Cl](2)(DMF)(OAc)}.CH(3)CN (6), {Eu[Zn(L(b))Cl](2)(DMF)(OAc)}.CH(3)CN (8), {Gd[Zn(L(b))Cl](2)(DMF)(2)}.Cl.2H(2)O (10), {Tb[Zn(L(b))Cl](2)(DMF)(2)}.Cl.2H(2)O (12), {Dy[Zn(L(b))Cl](2)(DMF)(2)}.Cl.2H(2)O (14), and {Pb[Zn(L(b))Cl](2)}.2H(2)O (15) exhibit a relatively rare sandwich-type structure with a central metal ion clamped by two [Zn(L)Cl](-) units. Photophysical studies indicate that all of the complexes exhibit luminescence both in solution and in solid sate, and there exists an energy transfer from the [Zn(L)Cl](-) unit to the central rare earth ions of Nd(III) (5 and 6), Tb(III) (11), and Dy(III) (for 13). In particular, systematic and comparative investigation of the photophysical properties of these trinuclear complexes reveals that the luminescence properties could easily be tuned by changing the central metal or the Schiff-base ligand.
TL;DR: In this article, the Ba 0.5 Sr 0.8 Fe 0.2 O 3− δ (BSCF) cathode for solid oxide fuel cell has been prepared by glycine-nitrate combustion process.
TL;DR: Maoniuping REE is a world-class deposit with 1.2mt of REO grading on average 2.89% REO, which is associated with Himalayan carbonatite-alkalic complexes in the eastern Indo-Asian collisional zone, Western Sichuan Province, China as discussed by the authors.