Zhong X.,Southwest University
Nonlinear Analysis: Real World Applications | Year: 2017
We study motions of the steady compressible viscous isothermal fluids in a bounded two dimensional domain governed by the Navier–Stokes equations. We obtain that there exists at least one weak solution to such a problem satisfying some integrability. The proof of this result is based on delicate estimates for the momentum equations and a bootstrapping argument. © 2016 Elsevier Ltd
News Article | May 4, 2017
Multinational feed additive producer Nutriad announced the appointment of Dr Wei Wang as Technical Manager for China. As part of an ongoing strategy to increase its presence in this dynamic market, Nutriad continues to invest in building technical and commercial support teams in China, allowing them to further improve their constant engagement and support to customers. BK Chew, APAC Director Nutriad, commented "China is the main growth engine within APAC and the appointment of Dr Wang will enable increased technical support for our applications in mycotoxin management and gut health.” Dr. Wei completed a total of 10 years of studies in animal nutrition, obtaining a BSc in Animal Science at Southwest University of Science & Technology, a MSc in Swine Nutrition at Sichuan Agriculture University and PhD in Applied Biological Science, Swine Nutrition at Ghent University. Dr Wang said, “I have always been fascinated by converting scientific knowledge on animal nutrition and health into practical solutions. As such I have admired Nutriad from the outside for many years and am excited to now become part of the Chinese team and support the company on its next steps in China.” Nutriad, headquartered in Belgium, provides feed additives and services to over 80 countries worldwide through a network of own offices and distributors, supported by 4 application laboratories and 5 manufacturing facilities located on 3 continents. Find out more at www.nutriad.com
Zhang J.,Nanyang Technological University |
Li C.M.,Nanyang Technological University |
Li C.M.,Southwest University |
Li C.M.,Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Energies
Chemical Society Reviews | Year: 2012
Nanoporous metals, a representative type of nanostructured material, possess intriguing properties to generate enormously promising potentials for various important applications. In particular, with the advances of fabrication strategies, nanoporous metals with a variety of superior properties including unique pore structure, large specific surface area and high electrical conductivity have fuelled up great interests to explore their electrocatalytic properties and greatly extend their emerging applications in electrochemical sensing and energy systems. This tutorial review attempts to summarize the recent important progress towards the development of nanoporous metals, with special emphasis on fabrication methods and advanced electrochemical applications, such as electrocatalysts, chemical sensors and energy systems. Key scientific issues and prospective directions of research are also discussed. © 2012 The Royal Society of Chemistry.
Zhang P.,Southwest University
Talanta | Year: 2013
In this contribution, an organic small molecule (OSM)-participating interaction between its aptamer and graphene oxide (GO) is investigated by taking coralyne as an example. Based on their interactions, a simple, rapid, highly sensitive and selective fluorometric method for the detection of coralyne is developed. GO can effectively quench the fluorescence of dye-labeled aptamer, while stronger binding of the aptamer and its target can make the fluorescence be recovered, which have been well demonstrated by the studies of the fluorescence spectra, fluorescence anisotropy, and circular dichroism spectra. In this case, the coralyne can be quantificationally detected by the variation of the fluorescence intensity, where GO acts as an efficient signal-to-background enhancer. With the increase of the coralyne, the fluorescence intensity increases gradually and linearly proportional to the concentration of the coralyne in the range of 10-700 nmol L(-1). This method is reliable, and has been successfully applied for the detection of coralyne in complicated matrixes. Copyright © 2013 Elsevier B.V. All rights reserved.
Jiang Y.,Southwest University
Journal of Contaminant Hydrology | Year: 2013
Generally, the DIC in karst groundwater is dominantly derived from carbonate dissolution by carbonic acid. However, recently increases in the inorganic carbon flux have been linked to human activities, which nitric and sulfuric acids may contribute to carbonate dissolution. In order to quantify the sources and fluxes of DIC, and evaluate the carbon isotopic evolution of groundwater in Southwest China, the carbonate dissolution by carbonic, sulfuric and nitric acids was evaluated by hydrochemistry and δ13C DIC of groundwater. The results show that: (1) groundwater collected from residential and agricultural areas, showed higher DIC concentrations and δ13CDIC than those in groundwater collected from forested and grass land areas; (2) the contributions of carbonate dissolution by carbonic acid to total DIC concentrations in groundwater collected from forested and grass land areas averaged 99%; (3) the contributions of carbonate dissolution by carbonic acid to total DIC concentrations in groundwater, collected from residential and agricultural areas, varied from 40% to 77% with a mean percentage of 62%; (4) while the contributions of carbonate dissolution by sulfuric and nitric acids to total DIC concentrations in groundwater, collected from residential and agricultural areas, varied from 23% to 60% with a mean percentage of 38%; and (5) the δ13CDIC approaching a value of around - 14‰, with a molar ratio between (Ca2 + + Mg2 +) and HCO3 - of around 0.5 in groundwater, indicated that the carbonate was dissolved by soil CO2 from C 3 vegetation under open system conditions. While the δ13CDIC varying from - 5‰ to - 11‰, with a variational molar ratio between (Ca2 + + Mg2 +) and HCO3 - of 0.5 to 0.8 in groundwater, indicated that carbonate dissolution was controlled by soil CO2 (from C3 vegetation), HNO3 and H2SO4. Also, this study indicated that the amount of soil or atmospheric CO2 consumed during carbonate weathering should be critically evaluated when sulfuric or nitric acids are involved. Thus, not only the exports of inorganic carbon have been enhanced, but also the concentrations of nitrate and sulfate in karst groundwater have been elevated due to carbonate dissolution by sulfuric or nitric acid. © 2013 Elsevier B.V. All rights reserved.
Cao H.,Southwest University
The Analyst | Year: 2013
We investigated the suitability of dithiocarbamate (DTC) capped Ag nanoparticles (NPs) as resonance light scattering (RLS) probes for the simultaneous sensing of Pb(2+) and cysteine. The DTC capping ligands are generated by a very simple in situ method through reaction of carbon disulfide with diethanolamine as primary precursor molecules under ultrasonic irradiation. This strategy was based on the fact that Pb(2+) could induce the aggregation of DTC-Ag NPs due to the strong metal affinity of DTC along with an enhanced RLS signal. After optimizing some experimental conditions (including the pH value of the solution, concentration of DTC-Ag NPs, and ion strength), a very simple and facile sensing system has been developed for the detection of Pb(2+) in water based on RLS technology. The proposed system promises excellent selectivity, a wide linear response range and high sensitivity for Pb(2+). The linear response range for Pb(2+) was from 0.01 μM to 60 μM. The limit of detection (S/N = 3σ) for Pb(2+) was as low as 4 nM. The proposed method was successfully used to detect Pb(2+) in river and tap water samples, indicating the potential of this new, sensitive and selective method in water quality monitoring. Meanwhile, due to the strong binding preference of cysteine toward Pb(2+) by the formation of Pb(2+)-S bonds, Pb(2+) was removed from the surfaces of the DTC-Ag NPs, leading to redispersion of DTC-Ag NPs, along with a decreased RLS signal. The possibility of the proposed system for the sensing of cysteine was also investigated.
Chen Z.,Southwest University
The Analyst | Year: 2013
We reported a new application of silver nanoparticles (NPs) for the visual sensing of aromatic polyphenols, such as gallic acid, pyrogallol and tannic acid, which is based on the intensified plasmon absorbance signals and visual changes from yellow to orange due to hydrogen-bonding recognition and subsequent catalytic oxidation of the target phenols by chitosan-capped Ag NPs (Ch-Ag NPs). The Ch-Ag NPs are generated by the well-known reaction of AgNO3 with NaBH4 and stabilized with chitosan which is a polysaccharide biopolymer with excellent dispersive properties and stability in aqueous media. After optimizing some experimental conditions, a very simple and facile sensing system has been developed for the detection of gallic acid, pyrogallol and tannic acid in water samples. The proposed system promises high selectivity toward gallic acid, pyrogallol and tannic acid, and other phenolic compounds including p-aminobenzoic acid, pentachlorophenol, 2,4,6-trinitrophenol, 2,4-dinitrophenol, p-nitrophenol, 1-naphthol, β-naphthol, p-aminophenol, catechol, hydroquinone, m-dihydroxybenzene, phloroglucin and phenol could not induce a color change even at 0.1 mM. The outstanding selectivity property of the proposed method for gallic acid, pyrogallol and tannic acid resulted from the Ch-Ag NPs-mediated reduction of Ag(+) by the target phenols. Also, a wide linear response range was obtained for the three targets. The linear response ranges for gallic acid, pyrogallol, and tannic acid were from 1 × 10(-5) to 1 × 10(-3) M, 1 × 10(-5) to 1 × 10(-2) M and 1 × 10(-6) to 1 × 10(-4) M with a respective detection limit (DL) of 1 × 10(-5), 1 × 10(-5), and 1 × 10(-6) M. The proposed method was successfully applied to detect target phenols in environmental water samples. Furthermore, because the color change from yellow to orange is observable by the naked eye, it is easy to realize visual detection of the target phenols without any instrumentation or complicated design. The experimental results reported here open up an innovative application of the catalytic reactivity of Ag NPs.
Southwest University | Date: 2015-02-16
Supercapacitor is an energy storage device with high power density and low energy density, and is normally used with a battery to satisfy ones needs for high power density and high energy density. The present invention provides a method to fabricate a novel battery type supercapacitor, with a multi-layered structure composed of a plurality of thin layers which is formed by alternately stacking high specific energy battery material and/or supercapacitor material such as metal oxides, metal hydroxides, metal sulfides, conductive polymers, carbon materials with reduced graphene oxide (rGO), to obtain a supercapacitor with both high specific energy density and high specific power density. Such a novel multi-layered structure composed of a plurality of thin layers formed by alternately stacking battery or capacitor material and rGO can not only ensure the obtained electrode to greatly improve the diffusion control of reaction particles, but also enhance its kinetic characteristic, so as to achieve both high power density and high energy density when used as a capacitor.
Southwest University | Date: 2014-09-24
A new battery type super capacitor electrode material having high power density and high energy density is provided. The electrode material is made from multi-layer of Bi_(2)S_(3)/CNT films and rGO films, wherein the layer number of Bi_(2)S_(3)/CNT films is same as the layer number of rGO films, and the Bi_(2)S_(3)/CNT films and rGO films are alternately stacked on top of each other. Further, a method of preparing an electrode material is provided. The methods includes coating Bi_(2)S_(3)/CNT and drying; depositing graphene oxide onto Bi_(2)S_(3)/CNT via electrochemical deposition; and, reducing graphene oxide to rGO by cyclic voltammetry to obtain a product. The capacitor electrode material has high energy density (460 Wh/kg), high power density (22802 W/kg) and specific capacitance (specific capacitance of 3568 F/g when current density is 22 A/g), and excellent cycling stability (remaining 90% of initial capacity after 1000 cycles).
Southwest University | Date: 2012-01-20
A system and process for determining and analyzing surface property parameters of a substance based on kinetic method is provided. The system comprises a sample processing system and a detection system. The sample processing system includes a reactor (3), a collector for liquid to be tested (5), and a container for liquid to be tested (6). The detection system includes a detecting electrode (13), a concentration and activity operator, a kinetic data processor, a surface property operation module, and a result output module. The process comprises: having the substance to be tested to be treated with an electrolyte solution, measuring activity of liquid to be tested upon reaction at a pre-set time interval, and processing with the kinetic data processor and the surface property operation module, so as to obtain surface property parameters of the substance to be tested. The present invention adopts kinetic method of ion exchange to overcome the issues associated with long reaction equilibrium time, not easy to determine equilibrium and not easy to accurately determine the value of m. Five parameters of the substance surface property can be calculated with only intercept and gradient of the linear regression equation obtained from the kinetic data, and the total amount of surface charge can also be directly determined.