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Showing papers by "Nanjing Tech University published in 2005"


Journal ArticleDOI
TL;DR: In this paper, the effect of fly ash with high replacing ratio of clay on firing parameters and properties of bricks were studied and the results indicate that the plasticity index of mixture of fly-ash and clay decrease dramatically with increasing of replacing ratio.

285 citations


Journal ArticleDOI
TL;DR: Regular BiPO4 nanorods, for the first time, and BiOCl lamellae have been successfully synthesized via a facile sonochemical method in a surfactant/ligand-free system under ambient air.
Abstract: Regular BiPO4 nanorods, for the first time, and BiOCl lamellae have been successfully synthesized via a facile sonochemical method in a surfactant/ligand-free system under ambient air. The as-prepared products are characterized by XRD, TEM, SAED, FE-SEM, HRTEM, and Raman spectroscopy. The effects of pH and ultrasound irradiation on the phase and morphology of the products are studied and the sonochemical formation mechanisms of 1D and 2D structures are discussed. TEM data from samples made after different reaction times suggest an ultrasound-induced nucleation and an oriented-attachment growth mechanism.

181 citations


Journal ArticleDOI
TL;DR: In this paper, the photolysis or photocatalysis of pyridaben followed pseudo-first-order kinetics, and the higher photocatalytic efficiency was obtained at λ ≥ 300nm.
Abstract: The TiO2 photoassisted degradation of pesticide pyridaben has been examined in acetonitrile/water suspensions under UV light irradiation mainly at wavelength longer than 360 nm. To distinguish from the accompanying photolytic phenomenon, the kinetics of direct photolytic and photocatalytic degradation of pyridaben in TiO2 suspensions were studied by two different UV wavelength irradiations (λ ≥ 300 nm and λ ≥ 360 nm). The results manifested that the photolysis or photocatalysis of pyridaben followed pseudo-first-order kinetics, the direct photolysis was dominant at λ ≥ 300 nm, and the higher photocatalytic efficiency was obtained at λ ≥ 360 nm. The photocatalytic degradation kinetics were studied under different conditions such as water content, pH, catalyst concentration as well as radiant flux, and the degradation rates were found to be strongly influenced by these parameters. A qualitative study of the degradation products generated during the process was performed by GC–MS. Up to fifteen compounds were detected as degradation intermediates, many of which were identical with those detected previously at λ ≥ 300 nm. We also analyzed the evolution of the degradation products semiquantitatively by plotting areas of the corresponding GC peaks as functions of irradiation time. Moreover, a complementary study using molecular model calculation was performed to forecast pyridaben's adsorption point on TiO2 particles and its weak position of molecular cleavage. On the basis of the analytical and kinetic results, a degradation mechanism was proposed. This work is significant to understand the photochemistry of pesticide pyridaben in the environmental treatment.

117 citations


Journal ArticleDOI
TL;DR: In this paper, the structure and diffusion properties have been studied for ethanol/water mixtures at 298.15 K and atmospheric pressure by molecular dynamics (MD) simulation, which was performed using a relatively simple rigid site-site model for ethanol and the TIP4P model for water.

111 citations


Journal ArticleDOI
Hong Xu1, Min Jiang1, Hui Li1, Dingqiang Lu1, Pingkai Ouyang1 
TL;DR: In this article, a bacterium with high poly(γ-glutamic acid) (γ-PGA) productivity was isolated from soil and identified taxonomically as Bacillus subtilis with the exception that it could not assimilate citric acid.

106 citations


Journal ArticleDOI
TL;DR: In this paper, the polyurethane-nanosilica hybrid was synthesized with frontal polymerization using 3-aminopropyltri-ethoxysilane (APTS).
Abstract: Polyurethane-nanosilica hybrids were synthesized with frontal polymer- ization. Structurally well-dispersed and stable hybrids were obtained via a two-step functionalization process: First, the silica was encapsulated with 3-aminopropyltri- ethoxysilane (APTS). Second, poly(propylene oxide) glycol, toluene 2,4-diisocyanate, 1,4-butanediol, and a catalyst (stannous caprylate) were dissolved in dimethylbenzene and mixed together at room temperature along with the modified nanosilica. A con- stant-velocity propagating front was initiated via the heating of the end of the tubular reactor. For the complete encapsulation of the silica with APTS, different weight ratios of APTS to silica were investigated. The polyurethane hybrids were characterized with Fourier transform infrared, differential scanning calorimetry, and transmission elec- tron microscopy. The polyurethane hybrids produced by frontal polymerization had the same properties as those produced by batch polymerization with stirring, but the frontal polymerization method required significantly less time and lower energy input than the batch polymerization method. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1670 -1680, 2005

103 citations


Journal ArticleDOI
TL;DR: In this paper, a MgO-based expansive agent using dolomite as raw material was studied and the expansion of resulting expansive agents by autoclaving testing and hot water curing at 80 °C was shown.

88 citations


Journal ArticleDOI
01 Jul 2005-Carbon
TL;DR: In this paper, a two-step polymerization of furfuryl alcohol (FA) involving slow polymerization (1st step) and sphere formation (2nd step) was shown to achieve high dispersibility of microporous carbon spheres.

82 citations


Journal ArticleDOI
TL;DR: In this article, a simple thermal process was used to pre-prepare monodispersed bismuth as triangular nanoplates and the crystal growth process and the influence of pH value, complexing agent, and surfactant were investigated.
Abstract: Monodispersed bismuth was successfully prepared as triangular nanoplates via a simple thermal process. Refluxing provided the driving force to facilitate the Ostwald ripening process growth of the platelike materials. All the nanoplates were highly oriented single crystals with the (001) planes as the basal planes. The crystal growth process and the influence of pH value, complexing agent, and surfactant were investigated. The characterization of mid-infrared showed that the as-prepared sample transferred from a semimetal to a semiconductor.

68 citations


Journal ArticleDOI
01 Jul 2005-Carbon
TL;DR: In this paper, the dissolution behavior of the inner iron cores under the treatments of HCl and HNO 3 acids at different conditions was studied and a practical route with the combined treatments of HO 3 and HCl acids has been optimized to produce carbon nanocages.

66 citations


Journal ArticleDOI
TL;DR: A simple chemical method for the production of single-crystalline alpha-Si(3)N(4) nanobelts has been developed, consisting of nitridation of a high-Si-content Fe-Si 'catalyst' by ammonia at 1300 degrees C.
Abstract: A simple chemical method for the production of single-crystalline α-Si3N4 nanobelts has been developed, consisting of nitridation of a high-Si-content Fe–Si 'catalyst' by ammonia at 1300 °C The as-synthesized product was characterized by means of x-ray diffraction, electron microscopy and energy-dispersive x-ray spectroscopy The α-Si3N4 nanobelts have widths of 60–120 nm, thicknesses of 10–30 nm and lengths up to microns Four intense green–blue luminescence bands at 398 nm (312 eV), 434 nm (286 eV), 492 nm (252 eV) and 540 nm (230 eV) were observed and analysed for the product, which indicates the potential applications in optoelectronics The growth mechanism has also been speculated upon The potential technological importance of the product, the simplicity of the preparation procedure, as well as the cheap commercial precursor of Fe–Si alloy particles makes this study both scientifically and technologically interesting

Journal ArticleDOI
TL;DR: In this paper, the electrocatalytic reduction of oxygen on carbon-supported Pt-Cr (1:1) alloy nanoparticle catalysts with two different metal loadings prepared via a carbonyl route was investigated based on the porous thin-film rotating disk-ring electrode technique and compared with that on ETEK Pt/C catalyst in pure and methanol-containing electrolytes.
Abstract: The electrocatalytic reduction of oxygen on carbon-supported Pt-Cr (1:1) alloy nanoparticle catalysts with two different metal loadings prepared via a carbonyl route was investigated based on the porous thin-film rotatingdisk-ring electrode technique and compared with that on E-TEK Pt/C catalyst in pure and methanol-containing electrolytes. The as-prepared Pt-Cr alloy nanoparticles, which have single-phase disordered structures, are well dispersed on the surface of carbon with a narrow size distribution even at 40 wt % metal loading. Such catalysts are stable in air up to 600°C. As compared to the Pt/C catalyst, the alloy catalysts showed slightly enhanced activity for the oxygen reduction reaction in pure acid electrolyte and significantly enhanced activity in the presence of methanol, and the ring-current measurements on the homemade catalysts showed a reduction in peroxide yield in pure acid solution. The enhanced activity could be ascribed to the effect of alloying on the initiation and extent of surface oxide formation. Oxygen reduction kinetic analysis indicated a potential dependence of the apparent number of electrons transferred per oxygen molecule during the reduction in methanol-containing solution. High methanol tolerance of Pt-Cr alloy catalysts during the oxygen reduction could be explained well by the lower reactivity of methanol oxidation, which may originate from the composition effect and the disordered structure of the alloy catalysts.

Journal ArticleDOI
Qun Cui1, Gang Tao1, Haijun Chen1, Xinyue Guo1, Huqing Yao1 
01 Feb 2005-Energy
TL;DR: In this paper, the performance of adsorption refrigeration was studied on simulation device of ad-sorbent refrigeration cycle, where water and ethanol were selected as refrigerants; 13x molecular sieve, silica gel, activated carbon, adsorbent NA and NB, proposed by authors, are selected as adsorbents.

Journal ArticleDOI
TL;DR: In this paper, the atom density profile, structure and diffusion behaviors of dense carbon dioxide fluid in clay-like slit pores have been studied by molecular dynamics simulation at 308.2 K. The orientational distribution and radial distribution functions of the confined CO2 molecules are presented in order to obtain the microscopic structure of interlayer fluids.

Journal ArticleDOI
TL;DR: Gallium phosphide nanot tubes with zinc blende structure were synthesized for the first time and the integration of the nanotubular structure with the unique intrinsic semiconducting properties of GaP might bring GaP nanotubes some novel optical and electronic properties and applications.
Abstract: Gallium phosphide nanotubes with zinc blende structure were synthesized for the first time. The as-prepared GaP nanotubes are polycrystalline with diameters of 30-120 nm and occasionally partially filled. The growth has been reasonably proposed to follow vapor-liquid-solid (VLS) mechanism. The integration of the nanotubular structure with the unique intrinsic semiconducting properties of GaP might bring GaP nanotubes some novel optical and electronic properties and applications.

Journal ArticleDOI
TL;DR: In this paper, the direct iso-paraffin synthesis from synthesis gas (CO+H2, syngas) via Fischer-Tropsch (FT) route was investigated in a consecutive dual-reactor system, in which FT reaction was carried out over Co/SiO2 catalyst in the upper reactor and hydroconversion of the FT hydrocarbons occurred over Pt/beta or Pd/beta catalysts in the lower reactor.

Journal ArticleDOI
TL;DR: In this article, a dynamic membrane with a uniform and compact structure was formed using the crossflow filtration technique, which gave good performance in separating oil from water using a model oil emulsion in an alkaline environment.

Journal ArticleDOI
TL;DR: In this article, electrical properties of alumina-based ceramic microfiltration membrane were studied using electro-osmosis measurements in the presence of various electrolytes, including NaCl, NH4Cl, CaCl2, FeCl 2, AlCl3, Na2SO4, NaS2S, Na3PO4, FeSO4 and Al2(SO4)3, which are commonly encountered in inorganic salt industry.

Journal ArticleDOI
TL;DR: In this article, the performance of various dealuminated zeolite catalysts such as H-mordenite (HM), H-beta (Hβ), USY and HMCM-22, for methylation of 2-methylnaphthalene (2-MN) were investigated in a high-pressure fixed-bed flow reactor.
Abstract: Catalytic performances of various dealuminated zeolite catalysts such as H-mordenite (HM), H-beta (Hβ), USY and HMCM-22, for methylation of 2-methylnaphthalene (2-MN) were investigated in a high-pressure fixed-bed flow reactor. Methanol and 1,2,4-trimethylbenzene (TMB) were used as solvents and methylating agents. Dealumination of HM substantially improved 2-MN conversion, 2,6-dimethylnaphthalene (2,6-DMN) selectivity and stability. HM after the steam treatment at 550 °C followed by acid leaching exhibited a high and a steady conversion of 40% with the very high 2,6-/2,7-DMN ratio of 2.4 for 5 h of time on stream. In contrast, the untreated HM showed a severe deactivation, with a conversion of 8.4% and the 2,6-/2,7-DMN ratio of 1.4. On the other hand, Hβ showed very high and nearly steady conversion, but with reduced selectivity for 2,6-DMN; USY showed initially high conversion but the value decreased and there was no selectivity for 2,6-DMN; and HMCM-22 showed low but steady conversion with low selectivity for 2,6-DMN for 5 h of time on stream. No promotion effect by dealumination on the conversion, stability, or selectivity was observed over Hβ, USY or HMCM-22. These distinguishing characteristics of these catalysts are discussed based on the differences in their porosity and acidity.

Journal ArticleDOI
TL;DR: Results indicate that tungsten oxide can be highly dispersed on Ce(0.5)Zr(0-5)O2 samples and the effect of the loading amount of WO3 on the reduction property of Cu2+ ions in a series of CuO/WO3/CZ samples has been observed and tentatively attributed to the formation of W O3 monolayer on CZ.
Abstract: XRD (X-ray diffraction), BET (Brunauer-Emmett-Teller), LRS (laser Raman spectra), XPS (X-ray photoelectron spectroscopy), and TPR (temperature-programmed reduction) are used to investigate the surface properties of CuO/WO3/Ce(0.5)Zr(0.5)O2 samples. The results indicate that (1) tungsten oxide can be highly dispersed on Ce(0.5)Zr(0.5)O2 (denoted as CZ hereafter) solid solution, with a dispersion capacity of about 0.8 mmol WO(3)/(100 m2 CZ), and comparatively, the supported tungsten oxide species are preferentially interacted with ceria component on the surface of CZ; (2) for CuO/WO3/CZ samples with a half-monolayer WO3 loading, i.e., xCu-0.4W-CZ series, the surface of CZ is only partially covered by the preloaded WO3) and the supported copper oxide species are dispersed on the remaining surface vacant sites on CZ as well as on top of the preloaded tungsten oxide, while for the samples preloaded with a full-monolayer WO3, i.e., xCu-0.8W-CZ series, only dispersed on the top of the preloaded tungsten oxide monolayer; (3) the effect of the loading amount of WO3 on the reduction property of Cu2+ ions in a series of CuO/WO3/CZ samples has been observed and tentatively attributed to the formation of WO3 monolayer on CZ and the different coordination environments of the dispersed Cu2+ ions are discussed on the basis of the consideration of the incorporation model proposed previously (Chen, Y.; Zhang, L. Catal. Lett. 1992, 12, 51).

Journal ArticleDOI
TL;DR: In this paper, cross-linked polyacrylamide (C-PAM) hydrogels were employed to reduce the crystal size of SAPO-34 molecular sieves in a vapor-phase transport process.

Journal ArticleDOI
TL;DR: A novel method for the removal of inorganic arsenic(III) (As(III), monomethylarsonate (MMA), and dimethylarsinate (DMA) from aqueous media, which involves the combined use of TiO2-photocatalyst and an adsorbent, which has a high ability of As(V) adsorption, under photo-irradiation.

Journal ArticleDOI
31 Mar 2005-Talanta
TL;DR: The microwave-assisted acid-digestion for the determination of metals in coal by ICP-AES was investigated, especially focusing on the necessity of adding HF, and the concentrations of major metals measured by the present method provided very high accordance with those from the authentic JIS (Japanese Industrial Standard) method.


Journal ArticleDOI
TL;DR: In this article, the effect of high concentration of FeSO 4 and flocculant of polyacrylamide (PAA) on the filtration process was investigated.

Journal ArticleDOI
TL;DR: The MCM41s incorporated with bimetallic copper and titanium were first synthesized by hydrolyzed the mixed solutions of sodium metasilicate (Na2SiO3), cuprammonia (Cu(NH3)4(NO3)2), and cetyltrimethylammonium bromide (CTAB) with diluted sulphuric acid containing titanium sulfate (Ti(SO4)2) as mentioned in this paper.

Journal ArticleDOI
Chang Liu1, Xiaohua Lu1, Gang Yu, Xin Feng1, Qitu Zhang1, Zhongzi Xu1 
TL;DR: In this paper, the reaction mechanism between hydrous titanium oxide and potassium carbonate at low temperatures was investigated by using XRD, TG, Raman spectra and TEM.

Journal ArticleDOI
TL;DR: In this article, the optimal preventive maintenance (PM) policies of aged plants such as fossil-fired power plants are discussed and the expected cost rate until PM is derived and optimal policies which minimizes it are discussed.
Abstract: Purpose – This paper considers and discusses analytically the optimal preventive maintenance (PM) policies of aged plants such as fossil‐fired power plants.Design/methodology/approach – Shocks are assumed to occur at a nonhomogeneous Poisson process and the total damage due to each shock is additive. The system undergoes the PM at a certain time or the total damage exceeds a managerial level. The expected cost rate until PM is derived and optimal policies which minimizes it are discussed.Findings – There exists a unique optimal time (T*) or managerial level (k*) which minimizes the expected cost rate. But there does not exist a positive pair (T*, k*), simultaneously.Research limitations/implications – The damage occurrence distribution is assumed to be nonhomogeneous Poisson one.Practical implications – Useful methods to consider the optimal PM policies for power plant engineers.Originality/value – This paper contributes to users of aged power plants economically and practically.

Journal ArticleDOI
TL;DR: In this paper, a segmented polyurethane was successfully prepared by frontal polymerization (FP), which is a mode of converting a monomer into a polymer via a localized reaction zone that propagates through the monomer.
Abstract: Frontal polymerization (FP) is a mode of converting a monomer into a polymer via a localized reaction zone that propagates through the monomer. In this study, segmented polyurethane was successfully prepared by FP. The reactants, poly (propylene oxide) glycol, 2, 4-toluene diisocyanate and 1,4-butanediol and the catalyst stannous caprylate, were mixed together at an initial temperature in the presence of dimethylbenzene (as the solvent). The reactions were thermally ignited at one end of the tubular reactor, and the resultant hot fronts propagated throughout the reaction reactor. No further energy was required for polymerization to occur. The effect factors of front velocity, stannous caprylate concentration and temperature on the FP, along with comparison of FP with bulk polymerization, were thoroughly investigated. Fourier transform infrared and differential scanning calorimetry were employed to characterize polyurethane (PU). The polymer materials obtained by FP displayed features similar to those obtained by batch polymerization. The reaction time of FP for preparing PU was lower than that of BP.

Journal ArticleDOI
TL;DR: In this paper, a new concept on the direct synthesis of middle iso-paraffins through the modified supercritical Fischer-Tropsch (FT) reaction was proposed and experimentally demonstrated with the combination of Co/SiO 2 and palladium-supported β zeolite (Pd/β) catalysts both in one-stage and two-stage fixed-bed reaction systems.