Showing papers by "Donghua University published in 2009"
TL;DR: It is concluded that further research on the phase development during cement hydration in the presence of heavy metals and thermodynamic modelling is needed to improve effectiveness of cement-based s/s and extend this waste management technique.
496 citations
01 Feb 2009
TL;DR: The high stability and recovery capacity of the chitosan-coated magnetic nanoparticles modified with alpha-ketoglutaric acid (alpha-KA-CCMNPs) suggest that these novel magnetic nanoadsorbents have potential applications for removing Cu(2+) from wastewater.
Abstract: Chitosan-coated magnetic nanoparticles (CCMNPs), modified with a biodegradable and eco-friendly biologic reagent, α-ketoglutaric acid (α-KA), was used as a magnetic nanoadsorbent to remove toxic Cu2+ ions from aqueous solution. The prepared magnetic nanoadsorbents were characterized by FTIR, TEM, VSM, XRD, and EDS. Factors influencing the adsorption of Cu2+, e.g., initial metal concentration, initial pH, contact time and adsorbent concentration were investigated. TEM images show that the dimension of multidispersed circular particles is about 30 nm and no marked aggregation occurs. VSM patterns indicate superparamagnetic properties of magnetic nanoadsorbents. EDS pictures confirm the presence of the Cu2+ on the surface of magnetic nanoadsorbents. Equilibrium studies show that Cu2+ adsorption data follow Langmuir model. The maximum adsorption capacity ( q max ) for Cu2+ ions was estimated to be 96.15 mg/g, which was higher than that of pure CCMNPs. The desorption data show no significant desorption hysteresis occurred. In addition, the high stability and recovery capacity of the chitosan-coated magnetic nanoparticles modified with α-ketoglutaric acid (α-KA-CCMNPs) suggest that these novel magnetic nanoadsorbents have potential applications for removing Cu2+ from wastewater.
386 citations
TL;DR: An attempt to give an overview on gas sensors using electrospun nanofibers comprising polyelectrolytes, conducting polymer composites, and semiconductors based on various sensing techniques such as acoustic wave, resistive, photoelectric, and optical techniques.
Abstract: Nanofibers fabricated via electrospinning have specific surface approximately one to two orders of the magnitude larger than flat films, making them excellent candidates for potential applications in sensors. This review is an attempt to give an overview on gas sensors using electrospun nanofibers comprising polyelectrolytes, conducting polymer composites, and semiconductors based on various sensing techniques such as acoustic wave, resistive, photoelectric, and optical techniques. The results of sensing experiments indicate that the nanofiber-based sensors showed much higher sensitivity and quicker responses to target gases, compared with sensors based on flat films.
379 citations
TL;DR: Fly ash was added as a seed material to enhance lime precipitation and the suspension was exposed to CO2 gas, which increased the particle size of the precipitate and significantly improved sedimentation of sludge and the efficiency of heavy metal removal.
346 citations
TL;DR: In this paper, the authors reported a simple strategy for constructing an all-solid-state AgBr-Ag-Bi 2 WO 6 nanojunction by a facile deposition-precipitation method with Bi 2WO 6 as the substrate.
Abstract: A semiconductor-based photocatalyst system, consisting of two visible-light-driven (VLD) components and one electron-transfer system, has a great potential to efficiently photocatalytically degrade pollutants. In this paper, we have reported a simple strategy for constructing an all-solid-state AgBr-Ag-Bi 2 WO 6 nanojunction by a facile deposition-precipitation method with Bi 2 WO 6 as the substrate. Two visible-light active components (AgBr, Bi 2 WO 6 ) and the electron-transfer system (Ag) are spatially fixed in this nanojunction system. Due to the presence of double visible-light active components, such a AgBr-Ag-Bi 2 WO 6 nanojunction system has the broadened visible-light photo-response range, and it also exhibits higher photocatalytic activity than photocatalysts containing single visible-light active component, such as Bi 2 WO 6 , Ag-Bi 2 WO 6 and AgBr-Ag-TiO 2 composite, for the degradation of the azo dye, Procion Red MX-5B and colorless pollutant pentachlorophenol. In addition, the initial dye concentration and pH value could greatly affect its photocatalytic activity, and the recycling experiments confirm that it is essentially stable during the photocatalytic process. In particular, the photocatalytic activity of AgBr-Ag-Bi 2 WO 6 nanojunction is superior to the sum of the activities of two individual photocatalysts (AgBr-Ag-TiO 2 and Bi 2 WO 6 ) that contain the same weight of AgBr or Bi 2 WO 6 , indicating the presence of a synergic effect between two visible-light active components in AgBr-Ag-Bi 2 WO 6 nanojunction. On the basis of the photocatalytic results and energy band diagram, the photocatalytic process that may have occurred on the AgBr-Ag-Bi 2 WO 6 nanojunction system is proposed; the vectorial electron transfer driven by the two-step excitation of both VLD components (AgBr and Bi 2 WO 6 ) contributes to its high photocatalytic activity. Therefore, this work provides some insight into the design of novel and efficient photocatalysts with multi-visible-light active components for enhancing VLD photocatalytic activity.
299 citations
TL;DR: In this article, the effects of surface modification on characteristics of jute fiber and mechanical properties of the biocomposite were evaluated, and the experimental results show that surface modification can remove surface impurities and reduce diameter of the jute fibres.
Abstract: A biocomposite was originally fabricated with biodegradable polymer PBS and jute fibre, and the effects of fibre surface modification on characteristics of jute fibre and mechanical properties of the biocomposite were evaluated in this paper. The experimental results show that surface modification can remove surface impurities and reduce diameter of jute fibres. Regarding the mechanical properties of biocomposites, it is observed that the biocomposites with jute fibres treated by 2% NaOH, 2 + 5% NaOH or coupling agent, respectively, an optimum in mechanical properties can obtain at fibre content of 20 wt.%, which exhibit an obvious enhancement in mechanical strength and modulus compared to the ones with untreated jute fibre. Furthermore, surface modification also exhibits less effects on flexural properties compared to tensile properties and more on flexural or tensile modulus than on the strength.
281 citations
TL;DR: Electrospun ultrafine fibers have the potential to be used as solid dispersions to improve the dissolution profiles of poorly water-soluble drugs or as oral fast disintegrating drug delivery systems.
Abstract: Oral fast-dissolving drug delivery membranes (FDMs) for poorly water-soluble drugs were prepared via electrospinning technology with ibuprofen as the model drug and polyvinylpyrrolidone (PVP) K30 as the filament-forming polymer and drug carrier. Results from differential scanning calorimetry, x-ray diffraction, and morphological observations demonstrated that ibuprofen was distributed in the ultrafine fibers in the form of nanosolid dispersions and the physical status of drug was an amorphous or molecular form, different from that of the pure drug and a physical mixture of PVP and ibuprofen. Fourier-transform infrared spectroscopy results illustrated that the main interactions between PVP and ibuprofen were mediated through hydrogen bonding. Pharmacotechnical tests showed that FDMs with different drug contents had almost the same wetting and disintegrating times, about 15 and 8 s, respectively, but significantly different drug dissolution rates due to the different physical status of the drug and the different drug-release-controlled mechanisms. 84.9% and 58.7% of ibuprofen was released in the first 20 s for FDMs with a drug-to-PVP ratio of 1:4 and 1:2, respectively. Electrospun ultrafine fibers have the potential to be used as solid dispersions to improve the dissolution profiles of poorly water-soluble drugs or as oral fast disintegrating drug delivery systems.
261 citations
TL;DR: A facile one-step hydrothermal approach to the synthesis of iron oxide (Fe(3)O(4)) nanoparticles (NPs) with controllable diameters, narrow size distribution, and tunable magnetic properties is reported.
Abstract: We report a facile one-step hydrothermal approach to the synthesis of iron oxide (Fe3O4) nanoparticles (NPs) with controllable diameters, narrow size distribution, and tunable magnetic properties. In this approach, the iron oxide NPs were synthesized by oxidation of FeCl2·4H2O in basic aqueous solution under an elevated temperature and pressure. Transmission electron microscopy and X-ray diffraction studies reveal that the particles are highly crystalline and that the diameters of the particles can be tuned from 15 to 31 nm through the variation of the reaction conditions. The NPs exhibit high saturation magnetization in the range of 53.3−97.4 emu/g and their magnetic behavior can be either ferromagnetic or superparamagnetic depending on the particle size. A superconducting quantum interference device magnetorelaxometry study shows that the size of the NPs significantly affects the detection sensitivity. The investigated iron oxide NPs may find many potential biological applications in cancer diagnosis an...
259 citations
TL;DR: In this paper, Diethylenetriamine-bacterial cellulose (EABC) was synthesized by amination with diethylENetriamines on bacterial cellulose.
248 citations
TL;DR: The purpose of the addressed filtering problem is to design a filter such that, for the admissible random measurement missing, stochastic disturbances, norm-bounded uncertainties as well as Stochastic nonlinearities, the error dynamics of the filtering process is exponentially mean-square stable.
242 citations
TL;DR: Compared with BC, CM-BC performs better adsorption, with the value of 9.67 mg (copper)/g, 22.56 mg (lead)/g for BC and 12.42 mg ( lead/g) forCM-BC, respectively, which closely follows pseudo-second-order rate model and the adsorptive isotherm data well follows the Langmuir model.
TL;DR: Melt blending of polylactide (PLA) and biodegradable polyamide elastomer (PAE) has been performed in an effort to toughen the PLA as discussed by the authors.
TL;DR: In this paper, a detailed study on the moisture sorption characteristics of bamboo strips and their influence on the interfacial shear strength (IFSS) of bamboo/vinyl ester composite was performed.
Abstract: Moisture absorption is a major concern for natural fibers used as reinforcement in structural composites. This paper reports a detailed study on the moisture sorption characteristics of bamboo strips and their influence on the interfacial shear strength (IFSS) of bamboo/vinyl ester composite. The IFSS determined by pull-out test decreased dramatically as the fabrication humidity increased. The bamboo strips provide a reservoir of moisture which diffuses into the interfacial region and inhibits the hardening of vinyl ester matrix. The interface of the bamboo/vinyl ester composite can also be damaged due to moisture exposure after fabrication. Post-fabrication exposure of composites to moisture was found to be less damaging than the moisture exposure during the composite fabrication. The IFSS of the composite decreased by nearly 40% in the first 9 d of water immersion. Further immersion up to 100 d did not cause any further reduction in interfacial shear strength.
TL;DR: In this article, two flat plate closed loop pulsating heat pipes in a thermal spreader configuration were used to study the effect of various operating parameters, including volumetric filling ratio of the working fluid, input heat flux and operating orientation, on the thermo-hydrodynamic performance.
TL;DR: In this article, the effects of fiber content, diameter, surface modification and arrangement forms on the biodegradability of poly(butylene succinate) (PBS)/jute composites were evaluated by compost-soil burial test.
TL;DR: In vitro release study indicated that threads made from the core-shell fibers could suppress the initial burst release and provide a sustained drug release useful for the release of growth factor or other therapeutic drugs.
Abstract: In this work, drug-loaded fibers and threads were successfully fabricated by combining electrospinning with aligned fibers collection Two different electrospinning processes, that is, blend and coaxial electrospinning, to incorporate a model drug tetracycline hydrochloride (TCH) into poly(L-lactic acid) (PLLA) fibers have been used and compared with each other The resulting composite ultrafine fibers and threads were characterized through scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and tensile testing It has been shown that average diameters of the fibers made from the same polymer concentration depended on the processing method The blend TCH/PLLA fibers showed the smallest fiber diameter, whereas neat PLLA fibers and core-shell TCH-PLLA fibers showed a larger proximal average diameter Higher rotating speed of a wheel collector is helpful for obtaining better-aligned fibers Both the polymer and the drug in the electrospun fibers have poor crystalline property In vitro release study indicated that threads made from the core-shell fibers could suppress the initial burst release and provide a sustained drug release useful for the release of growth factor or other therapeutic drugs On the other hand, the threads from the blend fibers produced a large initial burst release that may be used to prevent bacteria infection A combination of these results suggests that electrospinning technique provides a novel way to fabricate medical agents-loaded fibrous threads for tissue suturing and tissue regeneration applications
TL;DR: In this paper, a facile method for fabricating fibers with micro-and nano-porous structure by electrospinning a ternary system of nonsolvent/solvent/poly( l -lactic acid) is presented.
TL;DR: In situ synthesis of silver chloride (AgCl) nanoparticles was carried out under ambient conditions in nanoporous bacterial cellulose (BC) membranes as nanoreactors in this article.
TL;DR: This review focuses on the methods need for ILs separation from their "working" environment and proposed that the appropriate separation method should be selected according to different systems.
Abstract: Recycling of “green” solvents: Recycling of ionic liquids with high efficiency is of key importance on going from the laboratory-scale to large-scale industrial application of these solvents.
Recyclability is one of the reasons why ionic liquids (ILs) are attracting the attention of a growing number of scientists and engineers, but do we understand the recyclability of ILs in a real sense? For this purpose, this review focuses on the methods need for their separation from their “working” environment. Here we proposed that the appropriate separation method should be selected according to different systems. To better understand the separation of ILs, fundamental research on the existence forms (ions, ion pairs or supermolecule) of ILs in solvents is vitally important.
TL;DR: This paper is concerned with the H"~ filtering problem for a general class of nonlinear discrete-time Stochastic systems with randomly varying sensor delays, where the delayed sensor measurement is governed by a stochastic variable satisfying the Bernoulli random binary distribution law.
TL;DR: Benefiting from the synergy effect of carbon and ZnO, carbon-coated Zn O NRs also exhibited excellent photocatalytic activity toward the decomposition of methylene blue in a short time (approximately 14 min).
Abstract: This manuscript describes the accurate deposition of carbon on the surface of ZnO nanorods by a simple, microwave-assisted method and the studies on the cytotoxicity and photocatalytic activity of the C/ZnO hybrids. For the coating of carbon, the surface of the preformed ZnO nanorods were first modified by amino groups and then grafted by glucose, and finally they were irradiated in a microwave field to induce the transformation of glucose into carbon. With this method, the as-prepared carbon-coated product preserved the good dispersity and uniformity of the initial ZnO nanorods. Studies on the effects of carbon-coated ZnO nanorods and pure ZnO nanorods on cultured mouse fibroblast cells revealed that the coating of biocompatible carbon remarkably reduced the cytotoxicity of ZnO nanorods. In addition, benefiting from the synergy effect of carbon and ZnO, carbon-coated ZnO NRs also exhibited excellent photocatalytic activity toward the decomposition of methylene blue in a short time (∼14 min).
TL;DR: In this article, the authors synthesized and stabilized CdS nanoparticles on unique bacterial cellulose (BC) nanofibers in situ, and the obtained nanocomposite material have been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), fourier transformed infrared (FTIR), thermogravimetric analysis (TGA), ultraviolet-visible (UV-Vis) and photoluminescence (PL) spectroscopy.
TL;DR: In this article, the diameter variation of jute fibres was measured with an optical microscope and the strength predicted by modified Weibull distribution was more accurate than that of the two conventional models.
Abstract: The two-parameter Weibull distribution does not always adequately describe the experimental bast fibre strength at different gauge lengths. For this reason, it was modified by incorporating the diameter variation of jute fibres in this paper. The fibre diameter was measured with an optical microscope. The three-parameter Weibull model was also used to compare with the modified model. It was found that as the fibre diameter variation increased the tensile strength of the jute fibre decreased. The strength predicted by modified Weibull distribution was more accurate than that of the two conventional models. In addition, the breaking strength of jute fibre was less sensitive to gauge length than that of cotton fibre because the breaking of jute filament involves ultimate cells breaking repeatedly and matrix cracking.
TL;DR: It was found that Sydney was likely most suited to rainwater use, followed by Perth, Darwin, and then Melbourne, with Sydney having the shortest payback period compared to other cities.
TL;DR: In this paper, a five-dimensional symmetry algebra consisting of Lie point symmetries is computed for the nonlinear Schrodinger equation, which, together with a reflection invariance, generates two five-parameter solution groups.
TL;DR: Novel doughnut-shaped multi-layered drug delivery devices (DDDs) were developed with local variations of the drug and release-retardant material for providing linear release profiles and 3DP is capable of offering novel strategies for developing DDDs with complex design features for desired drug release profiles.
TL;DR: In this paper, the effect of applied voltage on the diameters of nanofibers is experimentally studied, revealing that the higher voltage favors the smaller diameter, and the minimal diameter reaches as small as 46.8 nm.
TL;DR: Results showed that PHPP-MTCNPs could be used in MRI monitored targeting PDT with excellent targeting and imaging ability and localization of nanoparticles in skin and hepatic tissue was significantly less than in tumor tissue, therefore photosensitivity and hepatotoxicity can be attenuated.
Abstract: Photodynamic therapy (PDT) has become an increasingly recognized alternative to cancer treatment in clinic. However, PDT therapy agents, namely photosensitizer (PS), are limited in application as a result of prolonged cutaneous photosensitivity, poor water solubility and inadequate selectivity, which are encountered by numerous chemical therapies. Magnetic chitosan nanoparticles provide excellent biocompatibility, biodegradability, non-toxicity and water solubility without compromising their magnetic targeting. Nevertheless, no previous attempt has been reported to develop an in vivo magnetic drug delivery system with chitosan nanoparticles for magnetic resonance imaging (MRI) monitored targeting photodynamic therapy. In this study, magnetic targeting chitosan nanoparticles (MTCNPs) were prepared and tailored as a drug delivery system and imaging agents for PS, designated as PHPP. Results showed that PHPP-MTCNPs could be used in MRI monitored targeting PDT with excellent targeting and imaging ability. Non-toxicity and high photodynamic efficacy on SW480 carcinoma cells both in vitro and in vivo were achieved with this method at the level of 0-100 microM. Notably, localization of nanoparticles in skin and hepatic tissue was significantly less than in tumor tissue, therefore photosensitivity and hepatotoxicity can be attenuated.
TL;DR: In this article, a facile approach to immobilizing zerovalent iron nanoparticles (ZVI NPs) into electrospun polymer nanofibrous mats was presented.
Abstract: We present a facile approach to immobilizing zerovalent iron nanoparticles (ZVI NPs) into electrospun polymer nanofibrous mats. Electrospun poly(acrylic acid) (PAA)/poly(vinyl alcohol) (PVA) nanofibrous mats were treated at an elevated temperature to render them water stable. The water-insoluble nanofibrous mats were then used as nanoreactors to complex ferric iron for subsequent formation and immobilization of ZVI NPs. Scanning electron microscopy (SEM) studies show that the smooth, uniform morphology of the electrospun nanofibrous mats does not significantly change after immobilization with ZVI NPs. Energy-dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and thermogravimetric analysis (TGA) were used to characterize the polymer nanofibers before and after the immobilization of ZVI NPs. We show that the formed ZVI NPs are uniformly distributed into the electrospun nanofibers with a mean partic...
TL;DR: Numerical simulations in scale-free complex networks are provided to show that the smaller fractional-order q, the larger control gain matrix D, thelarger tunable weight parameter beta, the bigger overall coupling strength c, the more capacity that the pinning scheme may possess to enhance the control performance of fractionAl-order complex networks.
Abstract: In this paper, we consider the pinning control problem of fractional-order weighted complex dynamical networks. The well-studied integer-order complex networks are the special cases of the fractional-order ones. The network model considered can represent both directed and undirected weighted networks. First, based on the eigenvalue analysis and fractional-order stability theory, some local stability properties of such pinned fractional-order networks are derived and the valid stability regions are estimated. A surprising finding is that the fractional-order complex networks can stabilize itself by reducing the fractional-order q without pinning any node. Second, numerical algorithms for fractional-order complex networks are introduced in detail. Finally, numerical simulations in scale-free complex networks are provided to show that the smaller fractional-order q, the larger control gain matrix D, the larger tunable weight parameter beta, the larger overall coupling strength c, the more capacity that the pinning scheme may possess to enhance the control performance of fractional-order complex networks.