Showing papers by "Nanjing Tech University published in 2006"
TL;DR: Single protein encapsulated into nanogels with uniformed size and controllable shell thickness exhibits similar biocatalytic behavior and significantly improved stability at high temperature and in the presence of organic solvent.
Abstract: Single protein encapsulated into nanogels with uniformed size and controllable shell thickness were prepared by surface acryloylation of a protein molecule followed by aqueous in situ polymerization. Compared to its free counterpart, the encapsulated protein exhibits similar biocatalytic behavior and significantly improved stability at high temperature and in the presence of organic solvent.
295 citations
TL;DR: In this paper, the effects of diluents, thermodynamic interactions, different quenching conditions and coarsening on the morphology of polyvinylidene fluoride (PVDF) membranes via thermally induced phase separation were investigated.
228 citations
TL;DR: In this paper, a carbon−sulfur-codoped TiO2 (TCS) was synthesized by the hydrolysis of tetrabutyl titanate in a mixed aqueous solution containing thiourea and urea.
Abstract: A novel photocatalyst, carbon−sulfur-codoped TiO2 (TCS) was synthesized by the hydrolysis of tetrabutyl titanate in a mixed aqueous solution containing thiourea and urea. The codoped TiO2 was also prepared directly by calcining amorphous or anatase TiO2 with a mixture of thiourea and urea. The as-prepared powders were characterized by X-ray diffraction (XRD), UV−visible reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy, and thermal analysis−thermogravimetry (TG-DSC). The photocatalytic activity was evaluated by the photodegradation of 4-chlorophenol under both UV and visible irradiation. By investigating the crystal structures, optical properties, and photocatalytic activities of various samples, we found that the wet chemistry process and the crystal transition process from amorphous to anatase seemed to be critical to the doping process.
190 citations
TL;DR: In this paper, the authors measured the effective complex magnetic permeability and dielectric permittivity of rubber radar absorbing material (RAM) with various carbonyl iron volume fractions with a vector network analyzer.
Abstract: We measured the effective complex magnetic permeability /spl mu//sub eff//sup */ and dielectric permittivity /spl epsiv//sub eff//sup */ spectra in rubber radar absorbing material (RAM) with various carbonyl iron volume fractions by using the transmission/reflection method with a vector network analyzer. We studied the effects of carbonyl iron content and rubber thickness on the microwave absorption properties in the frequency range of 2.6 to 18 GHz. Our mathematical analysis is based on electromagnetic theory. The results indicate that the effective complex magnetic permeability and dielectric permittivity values of the RAM increase as the carbonyl iron volume fraction increases. For sample thickness of 3.0 mm, an increase in carbonyl iron content reduces the minimum reflection loss from -1.3 to -23.9 dB and shifts the frequency of the minimum reflection loss from 15.5 to 3.5 GHz. For an equal volume fraction of carbonyl iron, the frequency of the minimum reflection loss decreases as the thickness is increased. However, the dip in the reflection loss plot (in decibels) initially decreases to a minimum value before it increases with a further increase in thickness. We determined the value of the reflection loss for the samples by the impedance matching degree (reflection coefficient), which depends on the thickness and composition of the RAM.
144 citations
TL;DR: In this article, the mechanical properties of coal gangue in the activatory process were studied by using the method of orthogonal experiment, and then the micromechanism of various coal gangues was determined by modern test methods such as scanning electron microscope (SEM) and nuclear magnetic resonance (NMR).
143 citations
TL;DR: In this paper, a series of nano-structured conducting functional composite oxides were synthesized through a non-ion selective EDTA-citrate-metal complexing process, which is characterized of solution-based, insensitive to environmental parameters, such as pH and humidity, and capable of synthesis of powder in large scale.
120 citations
TL;DR: In this article, the first synthesis of epoxy resin/polyurethane (EP/PU) hybrid networks via frontal polymerization (FP) was reported, where FP was thermally ignited at one end of the tubular reactor, and the resultant hot fronts propagated throughout the reaction vessel.
Abstract: We report the first synthesis of the epoxy resin/polyurethane (EP/PU) hybrid networks via frontal polymerization (FP). In a typical run, the appropriate amounts of reactants (poly(propylene oxide glycol), epoxy resin diglycidyl ether of bisphenol A, 2,4-toluene diisocyanate, and 1,4-butanediol with stannous caprylate (as the catalyst)) were mixed together at initial temperature in the presence of toluene (as the solvent). FP was thermally ignited at one end of the tubular reactor, and the resultant hot fronts propagated throughout the reaction vessel. Once initiated, no further energy was required for polymerization to occur. The dependence of the front velocity and front temperature on the catalyst concentration was thoroughly investigated. The samples were characterized with a Fourier transform infrared spectrometer, thermogravimetric analysis, and a scanning electron microscope. EP/PU hybrid networks synthesized by FP have the same properties as those synthesized by batch polymerization, but the FP met...
101 citations
TL;DR: A synergism mechanism of C(5)N-six-membered-ring-based growth through surface diffusion and vapor-liquid-solid growth through bulk diffusion was accordingly deduced and schematically presented and could help understand the CN(x)()-nanotube-related experimental phenomena in the literature.
Abstract: A series of bamboo-like CNx nanotubes have been synthesized from pyridine precursor by chemical vapor deposition with bimetallic Fe−Co/γ-Al2O3 catalyst in the range of 550∼950 °C. An unusual predomination of pyridinic nitrogen over graphitic nitrogen has been observed for the CNx nanotubes with reaction temperature below 750 °C. The pyridinic nitrogen decreases and the graphitic nitrogen increases with rising reaction temperature. A synergism mechanism of C5N-six-membered-ring-based growth through surface diffusion and vapor−liquid−solid growth through bulk diffusion was accordingly deduced and schematically presented. This mechanism could not only explain our own experimental results, but also understand the CNx-nanotube-related experimental phenomena in the literature, as well as be in accordance with the basic principle of diffusion kinetics. A promising route to the challenging topic for synthesizing regularly arranged C5N or high-N-content CNx nanotubes has also been suggested.
100 citations
TL;DR: In this article, a setf-supported asymmetric hollow-fiber membranes of mixed oxygen-ionic and electronic conducting perovskite Ba 0.5Sr0.5Co 0.8Fe0.2O3-delta (BSCF) were prepared by a combined phase-inversion and sintering technique.
Abstract: Setf-supported asymmetric hollow-fiber membranes of mixed oxygen-ionic and electronic conducting perovskite Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) were prepared by a combined phase-inversion and sintering technique. The starting inorganic powder was synthesized by combined EDTA-citrate complexing process followed by thermal treatment at 600 degrees C. The powder was dispersed in a polymer solution and then extruded into hollow-fiber precursors through a spinneret. ne fiber precursors were sintered at elevated temperatures to form gastight membranes, which were characterized by SEM and gas permeation tests. Performance of the hollow fibers in air separation was both experimentally and theoretically studied at various conditions. The results reveal that the oxygen permeation process was controlled by the slow oxygen surface exchange kinetics under the investigated conditions. The porous inner surface of the prepared perovskite hollow-fiber membranes considerably favored the oxygen permeation. The maximum oxygen flux measured was 0.031 mol-m(-2).s(-1) at 950 degrees C with the sweep gas flow rate of 0.522 mol(.)m(-2).s(-1). To improve the oxygen flux of BSCF perovskite membranes, future work should be focused on surface modification rather than reduction of the membrane thickness. (c) 2006 American Institute of Chemical Engineers.
94 citations
TL;DR: In this paper, the crystallization behavior of polyvinylidene fluoride (PVDF) in PVDF-dimethylphthalate (DMP) system was investigated in the liquid-liquid (L-L) phase separation region, solid-liquefloor (S-L), and different quenching conditions via thermally induced phase separation (TIPS).
Abstract: The crystallization behavior of PVDF (poly (vinylidene) fluoride) in PVDF-dimethylphthalate(DMP) system was investigated in the liquid–liquid (L–L) phase separation region, solid–liquid (S–L) phase separation region and different quenching conditions via thermally induced phase separation (TIPS). Differential scanning calorimetry (DSC) indicated the crystallinity of PVDF in PVDF-DMP system increased in the early stage of phase separation and polymer-rich phase crystallized completely in the late stage of phase separation. The scanning electron microscopy (SEM) showed the different quenching temperatures had effects on the spherulite size of polymer rich phase and the ultimate membrane structure in the different phase separation regions. The wide angle X-ray diffraction (WAXD) was used to quantify the crystal structure of PVDF in PVDF-DMP system. The α-phase PVDF was obtained when the system quenched to different temperatures above 40°C, and the area of diffraction peaks changed when quenching temperatures changed. While the β-phase PVDF was formed when PVDF-DMP system was quenched form liquid nitrogen and crystallized for 24 h in 25°C water bath. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3714–3719, 2006
93 citations
TL;DR: In this article, a stainless steel micro-channel reactor was used for the continuous synthesis of zeolite NaA, and it was found that aging of the synthesis solution was a key procedure to avoid the blockage of the microchannel.
TL;DR: Lead tungstate single crystals with dendritic, flowery and star-like structures have been prepared via a facile, ethylene glycol (EG)-assisted sonochemical method and the oriented attachment process accompanying Ostwald ripening was proposed for the possible formation mechanism.
Abstract: Lead tungstate single crystals with dendritic, flowery and star-like structures have been prepared via a facile, ethylene glycol (EG)-assisted sonochemical method. The concentrations of EG and ultrasound irradiation were found to play crucial roles in the morphology control of the final products. The growth process was investigated by carefully following time-dependent experiments, and the oriented attachment process accompanying Ostwald ripening was proposed for the possible formation mechanism. The optical properties, such as the Raman spectra and photoluminescence (PL) spectra, of the obtained PbWO4 crystals were studied.
TL;DR: Titania ultrafiltration membranes were successfully fabricated by a new route, which was directly derived from the nanoparticles suspension that was the intermediate product prior to dry and calcine in the synthesis of nanoparticle by a wet chemical method as discussed by the authors.
TL;DR: In this article, the Carman-Kozeny (C-K) and Hagen-Poiseuille (H-P) equations were improved to predict water permeability of ceramic membranes.
TL;DR: A sixth-order compact scheme coupled with Alternating Direction Implicit methods and applied to parabolic equations in both 2-D and 3-D is developed and unconditional stability is proved for linear diffusion problems with periodic boundary conditions.
Abstract: In this paper we develop a sixth-order compact scheme coupled with Alternating Direction Implicit (ADI) methods and apply it to parabolic equations in both 2-D and 3-D. Unconditional stability is proved for linear diffusion problems with periodic boundary conditions. Numerical examples supporting our theoretical analysis are provided.
TL;DR: In this article, the intrinsic universality of percolation exponents is revealed by analyzing the power-law relationship between two different scales (microstructure and macroscopic properties).
Abstract: The fundamental mechanism of the non-universality of exponent t in the classical percolation equation is discussed on the basis of the comparison of lattice percolation and continuum percolation systems in the present study. The intrinsic universality of percolation exponents is revealed by analyzing the power-law percolation relationship between two different scales (microstructure and macroscopic properties). In view that the classical percolation equation with fitting parameters lacks a clear correlation to the microstructure features, a physically based percolation model is proposed to characterize the effective electrical conductivity of particle filled composites by means of the combination of effective medium (EM) and percolation equations with universal exponents. It is shown that the present model agrees well with the experimental data. Furthermore, the effect of particle shape on the percolation threshold and the effect of electrical conductivity of particle on the effective properties of composites are discussed.
TL;DR: In this article, a perovskite-type oxygen-permeable membrane of SrCo0.4Fe0.5Zr0.1O3-δ (SCFZ) was used for the membrane reactor.
Abstract: In this study, we proposed coupling the thermal decomposition of carbon dioxide (CO2 → CO + 1/2O2) with the partial oxidation of methane (POM) to syngas (CH4 + 1/2O2 → CO + 2H2) in a dense mixed-conducting membrane reactor, in which the reaction of CO2 decomposition took place in one side of the membrane and the POM reaction occurred in the other side of the membrane simultaneously (or methane reacted with oxygen that was permeated through the membrane from the CO2 decomposition, to produce H2 and CO over supported transition metal catalysts). A perovskite-type oxygen-permeable membrane of SrCo0.4Fe0.5Zr0.1O3-δ (SCFZ) was used for the membrane reactor. The effects of temperature and the feed flow rates of CO2 and CH4 on the reaction performance of the SCFZ membrane reactor were investigated. It was found that the CO2 conversion increased with increasing the temperature and decreased with increasing the feed flow rates of CO2 or with decreasing the feed flow rates of CH4. At 1173 K, the CO2 conversion reached about 11.1%, and the CH4 conversion, CO selectivity, and the ratio of H2/CO were 84.5%, 93%, and 1.8, respectively. © 2006 American Institute of Chemical Engineers AIChE J, 2006
TL;DR: In this article, the losses of strength, mass and air void characteristics of roller compacted concrete (RCC) containing fly ash, superplasticizer and a novel MgO-bearing expansive agent (HNM) were studied using the freezing-thawing method ASTM C666.
TL;DR: The complete protein pattern of cellulase and hemicellulase genes was studied through the Genome-wide analysis in Trichoderma reesei and four groups were created and analyzed by phylogenetic analysis, in which 8 beta-glucosidases appeared to be non-secreted proteins.
Abstract: The complete protein pattern of cellulase and hemicellulase genes was studied through the Genome-wide analysis in Trichoderma reesei. The genome database revealed the presence of 39 ORFs encoding related proteins, including 32 enzymes with a catalysis domain related to cellulases and hemicellulases and 7 related proteins with a cellulose-binding module (CBM). Ten of these encoded yet undescribed enzymes, including six novel beta-glucosidases or xylosidases, two putative xylanases and two undescribed mannases. To better illustrate the relation of these 39 related proteins, four groups were created and analyzed by phylogenetic analysis: group A corresponding to xylanases, group B belonging to mannases and acting to degrade mannan; group C containing all known and putative cellulose-degrading proteins that have highly conserved CBMs; and group D containing beta-glucosidase and beta-xylosidase. Group D was the largest group, in which 8 beta-glucosidases appeared to be non-secreted proteins.
TL;DR: It is demonstrated that CTGF induces production of fractalkine, MCP-1, and RANTES via the p42/44 MAPK-, PI3-K/Akt-, and NF-kappaB-dependent signal pathway, and LXA downregulates the above effects of CTGF on rat mesangial cells.
TL;DR: In this article, the friction and wear behavior of polytetrafluoroethylene (PTFE) filled with potassium titanate whiskers (PTW) was studied.
TL;DR: It was found that the temperature has little effect on the confined water molecules in carbon nanotubes, but on the other hand, the simulation results showed that because of the difference in helicity between (6, 6) and (10, 0) CNTs, the modification by hydrophilic carboxyl acid functional groups (-COOH) results in a different response to the C NTs.
Abstract: Carbon nanotubes show exceptional properties that render them promising candidates as building blocks for nanostructured materials. Many ambitious applications, ranging from molecular detection to membrane separation, require the delivery of fluids, in particular aqueous solutions, through the interior of carbon nanotubes (CNT). To foster such applications, an understanding of the properties of water molecules confined in carbon nanotubes at the molecular level is needed. In this work we report a study of temperature and helicity effects on static properties of water molecules confined in modified CNT by molecular dynamics simulations. It was found that the temperature has little effect on the confined water molecules in carbon nanotubes. But on the other hand, the simulation results showed that because of the difference in helicity between (6, 6) and (10, 0) CNTs, the modification by hydrophilic carboxyl acid functional groups (-COOH) results in a different response to the CNTs, which in turn have control over the flow direction of water molecules in these CNTs.
TL;DR: In this paper, a new series of Al2O3-doped SrCo0.8Fe0.2O 3−δ (SCFA) mixed conducting oxides were synthesized by the conventional solid-state reaction method.
TL;DR: In this paper, the effects of cation substitution on the sintering characteristics, thermal expansion and electrical conductivity properties of La(AE)Cr(M)O 3 (AE Mg, Ca, Sr, M Ni, Cu, Co) were investigated.
TL;DR: Polycrystalline hollow AlN nanospheres with diameters ranging from 20 to 200 nm and shell thickness of about 10 nm were successfully synthesized through the reaction of irregular Al nanopowder with a CH4-NH3 mixture at around 1000 °C by the self-templated method.
Abstract: Polycrystalline hollow AlN nanospheres with diameters ranging from 20 to 200 nm and shell thickness of about 10 nm were successfully synthesized through the reaction of irregular Al nanopowder with a CH4–NH3 mixture at around 1000 °C by the self-templated method. The products were well characterized by X-ray diffraction, high-resolution transmission electron microscopy, Raman spectroscopy and photoluminescence measurements. The photoluminescence properties of the hollow AlN nanospheres showed the routine blue emissions for AlN nanoparticles as well as an unusual green emission at around 533 nm, indicating the potential for luminescent devices. The synthesis mechanism was reasonably speculated and further supported by the similar synthesis of hollow AlN nanospheres from regular Al particles.
TL;DR: In this article, a study of the three-dimensional vibration characteristics of thick circular plates resting on an elastic foundation is presented, which is based on the 3D small-strain, linear and exact elasticity theory.
TL;DR: In this paper, a pyrolysis of melamine with NaN3-Fe-Ni and Ni catalysts at high temperature and high pressure was used to obtain nitrogen-doped conical hollow and bamboo-like carbon nanotubes (CNTs).
TL;DR: In this article, the eigenvalue equation of the coupled system was derived for a beam with continuously distributed spring-mass and the beam in each segment was uniform. But the authors did not consider the effect of the number of segments having different natural frequencies.
TL;DR: It is suggested that different Mn2+ concentration could change γ-PGA stereochemical composition through regulating glutamate racemase activity, which was different from other γ -PGA producers in species of B. subtilis ever reported.
TL;DR: According to microanalytical investigations, it is shown that the concrete of Yongan Dam is deteriorated due to the thaumasite form of sulfate attack (TSA).