摘要:
This paper is concerned with the generalized Hamy symmetric function Sigma(n)(x, r; f) = Sigma(1 <= i1<i2<...<ir <= n) f(Pi(r)(j=1) x(ij)(1/r)), where f is a positive function defined in a subinterval of (0, +infinity). Some properties, including Schur-convexity, geometric Schur-convexity and harmonic Schur-convexity are investigated. As applications, several inequalities are obtained, some of which extend the known ones. (C) 2010 Elsevier Inc. All rights reserved.
摘要:
Taking the heterogeneity character of concrete into account, this paper presents an equivalent probabilistic model for failure study of concrete in which the heterogeneity of concrete is considered by assuming that the material properties conform to the Weibull distribution law and by using mesoscale mesh of finite elements. The study is divided into three parts. In the first part, a spatial correlation length factor is developed into the Weibull distribution formula so that the spatial correlation of local continuity of material properties can be considered. The second part presents a series of numerical analyses for investigating the size effect of self-compacting concrete (SCC) based on the equivalent probabilistic model, and a comparison is made between the simulation results and compression test measurements for illustrating the size effect on uniaxial compression strength and failure pattern of the SCC concerned. It is shown that the numerical model can provide reasonable predictions in the analysis of the size effect of SCC. In the final part, as an engineering application of the presented model, the damage and fracture behavior of the Koyna gravity dam during the 1967 earthquake are analyzed. Influences of concrete parameters on the crack pattern and failure modes of the dam prototype during the event are discussed. DOI: 10.1061/(ASCE)MT.1943-5533.0000179. (C) 2011 American Society of Civil Engineers.
摘要:
The adsorption of chromium (VI) ions from aqueous solution by ethylenediamine-modified cross-linked magnetic chitosan resin (EMCMCR) was studied in a batch adsorption system. Chromium (VI) removal is pH dependent and the optimum adsorption was observed at pH 2.0. The adsorption rate was extremely fast and the equilibrium was established within 6-10 min. The adsorption data could be well interpreted by the Langmuir and Temkin model. The maximum adsorption capacities obtained from the Langmuir model are 51.813 mg g(-1), 48.780 mg g(-1) and 45.872 mg g(-1) at 293, 303 and 313 K, respectively. The adsorption process could be described by pseudo-second-order kinetic model. The intraparticle diffusion study revealed that film diffusion might be involved in the present case. Thermodynamic parameters revealed the feasibility, spontaneity and exothermic nature of adsorption. The sorbents were successfully regenerated using 0.1 N NaOH solutions. (C) 2010 Elsevier B.V. All rights reserved.
摘要:
In the title compound, [Bi(C20H23N)(CF 3SO3)], the BiIII ion shows a distorted pseudo-trigonal-bipyramidal geometry, with two C atoms and a lone electron pair of the Bi atom in equatorial positions and the N and O atoms at the apical positions. The cyclohexyl group is disordered over two orientations with site-occupancy factors of 0.600 (14) and 0.400 (14).
期刊:
Journal of Engineering for Gas Turbines and Power,2010年133(8):84502-1-84502-3 ISSN:0742-4795
通讯作者:
Wang, Jing-song
作者机构:
[Wang, Jing-song; Bao, Zheng-lei; Chen, Si-guang] Univ South China, Hunan Key Lab Pollut Control & Resource Reuse, Sch Urban Construct, Hengyang 421001, Hunan, Peoples R China.;[Yang, Jin-hui] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
通讯机构:
[Wang, Jing-song] U;Univ South China, Hunan Key Lab Pollut Control & Resource Reuse, Sch Urban Construct, Hengyang 421001, Hunan, Peoples R China.
会议名称:
18th International Conference on Nuclear Engineering (ICONE-18)
会议时间:
MAY 17-21, 2010
会议地点:
Xian, PEOPLES R CHINA
会议主办单位:
[Wang, Jing-song;Bao, Zheng-lei;Chen, Si-guang] Univ South China, Hunan Key Lab Pollut Control & Resource Reuse, Sch Urban Construct, Hengyang 421001, Hunan, Peoples R China.^[Yang, Jin-hui] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
关键词:
uranium;aqueous;chitosan;ferrous;discharge standard
摘要:
This study focuses on developing a new method to remove uranium from aqueous solution. Chitosan and ferrous ions were used together to remove uranium ions from aqueous solution. Through two-step pH adjustment, the uptake behavior of chitosan and ferrous ions toward uranium in aqueous solution using batch systems was studied in different experimental conditions. The experimental results indicated that the removal of uranium by the synergetic effect of chitosan and ferrous ions was more effective than the way of adsorbing uranium ions by chitosan alone. Under the given experimental conditions, the concentration of the residual uranium in the effluent after the chitosan and ferrous ion treatment could meet the discharge standard (< 0.05 mg l(-1)) when the initial concentration of uranium ions was 10 mg l(-1) or 100 mg l(-1). The synergetic effect of chitosan and ferrous ions, including adsorption, coacervation, and coprecipitation, was responsible for the high removal rate of uranium. [DOI: 10.1115/1.4002817]
期刊:
Journal of Environmental Radioactivity,2010年101(6):504-508 ISSN:0265-931X
通讯作者:
Wang, Jing-song
作者机构:
[Wang, Jing-song; Bao, Zheng-lei; Xie, Shui-bo; Hu, Xin-jiang] Univ S China, Sch Urban Construct, Hengyang 421001, Hunan, Peoples R China.;[Wang, Jing-song; Xie, Shui-bo] Univ S China, Hunan Key Lab Pollut Control & Resource Reuse, Henyang 421001, Hunan, Peoples R China.;[Liu, Yun-guo; Hu, Xin-jiang] Hunan Univ, Coll Environm Sci & Engn, Changsha 410082, Hunan, Peoples R China.;[Wang, Jing-song] Univ S China, Sch Urban Construct, 28 W Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
通讯机构:
[Wang, Jing-song] U;Univ S China, Sch Urban Construct, 28 W Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
会议名称:
9th International Conference on Biogeochemistry of Trace Elements
会议时间:
JUL, 2007
会议地点:
Beijing, PEOPLES R CHINA
会议主办单位:
[Wang, Jing-song;Hu, Xin-jiang;Xie, Shui-bo;Bao, Zheng-lei] Univ S China, Sch Urban Construct, Hengyang 421001, Hunan, Peoples R China.^[Wang, Jing-song;Xie, Shui-bo] Univ S China, Hunan Key Lab Pollut Control & Resource Reuse, Henyang 421001, Hunan, Peoples R China.^[Hu, Xin-jiang;Liu, Yun-guo] Hunan Univ, Coll Environm Sci & Engn, Changsha 410082, Hunan, Peoples R China.
关键词:
Immobilized beads;Aspergillus fumigatus;Biosorption;Uranium (VI);Pseudo-second order
摘要:
Biosorption of uranium (VI) ions by immobilized Aspergillus fumigatus beads was investigated in a batch system. The influences of solution pH, biosorbent dose, U (VI) concentration, and contact time on U (VI) biosorption were studied. The results indicated that the adsorption capacity was strongly affected by the solution pH, the biosorbent dose and initial U (VI) concentration. Optimum biosorption was observed at pH 5.0, biosrobent dose (w/v) 2.5%, initial U (VI) concentration 60 mg L-1. Biosorption equilibrium was established in 120 min. The adsorption process conformed to the Freunlich and Temkin isothermal adsorption models. The dynamic adsorption model conformed to pseudo-second order model. (C) 2010 Elsevier Ltd. All rights reserved.
摘要:
Air-stable hypervalent organobismuth(III) tetrafluoroborate (C6H11N(CH2C6H4)2BiBF4) was synthesized and characterized by spectroscopic and X-ray crystallographic techniques. The compound shows good catalytic efficiency in the allylation reaction of different aldehydes with tetraallyltin in a medium of aqueous methanol, giving the corresponding homoallylic alcohols in excellent chemoselectivity and yields.
摘要:
An air-stable hypervalent organobismuth (III) perfluorooctanesulfonate was synthesized and characterized by spectroscopic and X-ray crystallographic techniques, and found to exhibit high catalytic efficiency towards one-pot Mannich-type reaction of ketones with aromatic aldehydes and aromatic amines in water. This catalyst also shows good recyclability and reusability. This catalytic system would provide a simple, efficient and 'green' avenue towards the synthesis of beta-amino ketones. (C) 2009 Published by Elsevier B.V.
摘要:
To enhance the impact strength of polyamide 6, hydrolytic polymerization modification by the polyaminoamide-g-poly(ethylene glycol) (PAAEG) derivatives with poly(ethylene glycol) (PEG) molecular weight of 400-10000 was studied. Amide groups of polyaminoamide segments were postulated to form hydrogen bonding with polyamide 6, and hydroxy groups of PAAEG units were expected to react with carboxylic acid groups of polyamide 6 forming copolymers during the polymerization. The improved compatibility in amorphous regions of blends has been confirmed by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) of fracture surfaces. The effects of PAAEG on the water absorption and notch sensitivity of blends were investigated, using water uptake measurement and mechanical testings, respectively. For comparison, pure polyamide 6 and the blend of PEG/polyamide 6 were also investigated. The addition of PAAEG retarded the crystallization of polyamide 6, but did not make remarkable influences on its crystalline structure. As a consequence of the strong interactions between the dispersed phases and polyamide 6 matrices, PAAEG was a more suitable additive for improving the notched impact strength of polyamide 6 than PEG.
摘要:
The graft copolymer of polystyrene and polyamide 6 (PS-g-PA6) was investigated by anionic polymerization of epsilon-caprolactam (CL), using the free radical copolymer of styrene and a kind of allyl monomer containing N-carbamated caprolactam group as macroactivator (PS-CCL). CL monomers were grafted onto PS-CCL backbone via initiating N-carbamated caprolactam (CCL) pendants along its backbone to form the graft copolymer in the presence of catalyst sodium caprolactamate. The macroactivator was characterized by Fourier-transform infrared spectroscopy and nuclear magnetic resonance, and the graft copolymer by the selective solvent extraction technique using methanol and chloroform as solvents. PS-g-PA6 copolymers with different PS content were synthesized to study the effect of PS on morphology, crystallinity, dimensional stability, and thermal properties, using scanning electron microscopy, X-ray diffraction, water absorption measurement, thermogravimetric analysis, and differential scanning calorimetry. The results show the percentage crystallinity of graft copolymer decreases with increasing PS content, but the addition of PS scarcely influences the crystalline structure of PA6. The graft copolymer has improved thermal properties and dimensional stability. (C) 2008 Wiley Periodicals.