A fractal kinetic model for heap leaching of uranium ore with fractal dimension of varied particle size distribution
作者：
Ding, De-Xin* ;Fu, Hai-Ying;Ye, Yong-Jun;Hu, Nan;Li, Guang-Yue;...
期刊：
Hydrometallurgy ,2013年136:85-92 ISSN：0304-386X
通讯作者：
Ding, De-Xin
作者机构：
[Fu, Hai-Ying; Li, Guang-Yue; Song, Jian-Bin; Ye, Yong-Jun; Hu, Nan; Ding, De-Xin; Wang, Yong-Dong] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
通讯机构：
[Ding, De-Xin] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
关键词：
Fractal kinetic model;Heap leaching;Fractal dimension;Uranium ore;Particle size distribution
摘要：
The varied particle size distribution of uranium ore for heap leaching, with its particle sizes ranging from 0 to 9 mm, is taken from a uranium mine in South China. Five uranium ore samples with the fractal dimensions (D) of particle size distribution of 1.6, 1.8, 2.0, 2.2 and 2.4, respectively, are further prepared by mixing different weights of the uranium ores for the size fractions of + 8/- 9, + 7/- 8, + 6/- 7, + 5/- 6, + 4/- 5, + 3/- 4, + 2/- 3, + 1/- 2, + 0.5/- 1 and - 0.5 mm, respectively. The five samples are leached in columns to investigate the influences of the fractal dimensions of particle size distribution on their leaching performances. The leaching data are analyzed using the shrinking core model, and the whole process of the column leaching is divided into two phases based on the pH and the potential vs. saturated calomel electrode (SCE) of the pregnant leach solution (PLS) from the columns. When the value of pH is greater than 2.0 and the potential vs. SCE is less than 400 mV, the leaching is in the first phase, the rate constant during the first phase k<inf>1</inf> is controlled by initial rate constant k<inf>0</inf> and the increase rate parameter λ, and k<inf>0</inf>, λand the length of the period for the first phase T<inf>1</inf> all have linear relationships with D. When the value of pH is less than or equal to 2.0 and the potential vs. SCE is greater than or equal to 400 mV, the leaching is in the second phase, and the rate constant during the second phase k<inf>2</inf> has non-linear relationship with D. From these analytical results, a fractal kinetic model for heap leaching of the uranium ore with fractal dimension of varied particle size distribution is established. And the experimental results show that the model is capable of predicting the recovery of uranium for heap leaching of uranium ore with fractal dimension of varied particle size distribution. ©2013 Elsevier B.V.
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英文
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Screening of native hyperaccumulators at the huayuan river contaminated by heavy metals
作者：
Hu Nan;Zheng Jifang* ;Ding Dexin;Li Guangyue;Yin Jie;...
期刊：
Bioremediation Journal ,2013年17(1):21-29 ISSN：1088-9868
通讯作者：
Zheng Jifang
作者机构：
[Yin Jie; Yu Jia; Li Guangyue; Hu Nan; Ding Dexin; Chen Xin; Zheng Jifang] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Zheng Jifang] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
关键词：
Alternanthera philoxeroides;Huayuan River;hyperaccumulator;metal pollution;phytoremediation
摘要：
Plant, soil, and sediment samples were taken from the Fuqiao area within the Huayuan River basin in South China. Concentrations of manganese, zinc, cadmium, and lead in the samples were measured, and the characteristics of the plant samples to absorb, transfer, and accumulate the target metals were analyzed. It was indicated that the concentrations of target metals in 13 plant samples greatly exceeded the background values of target metals in plants over the world, and that the plant species might evolve to the accumulating ecotypes for the target metals under the long-term stress from the contaminated environment. Among 13 plant species, Alternanthera philoxeroides exhibited the highest accumulation capacities for the target metals, amounting to 6511, 13,784, 155, and 104 mg/kg in its shoots for manganese, zinc, cadmium, and lead, respectively. Its bioaccumulation coefficients for manganese, zinc, cadmium, and lead were 5.08, 49.23, 36.78, and 34.81, respectively, and its transfer factors for manganese, zinc, cadmium, and lead were 7.53, 3.19, 7.38, and 1.29, respectively. The results showed that Alternanthera philoxeroides satisfied the criteria for the hyperaccumulator for zinc and cadmium, and that it might be a potential native plant species for phytoremediation of the contaminated soil, sediment, and river water by the target metals within the basin. © 2013 Taylor and Francis Group, LLC.
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英文
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Comprehensive Genomic Characterization of Campylobacter Genus Reveals Some Underlying Mechanisms for its Genomic Diversification
作者：
Zhou, Yizhuang;Bu, Lijing;Guo, Min;Zhou, Chengran;Wang, Yongdong;...
期刊：
PLOS ONE ,2013年8(8):e70241- ISSN：1932-6203
通讯作者：
Chen, Liyu
作者机构：
[Zhou, Yizhuang; Guo, Min] BGI Shenzhen, Shenzhen, Guangdong, Peoples R China.;[Bu, Lijing] Univ New Mexico, Dept Biol, Albuquerque, NM 87131 USA.;[Zhou, Chengran] Sichuan Univ, Dept Biol, Chengdu 610064, Sichuan Provinc, Peoples R China.;[Wang, Yongdong] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang, Hunan, Peoples R China.;[Chen, Liyu] Cent South Univ, Xiangya Sch Med, Dept Microbiol, Changsha, Hunan, Peoples R China.
通讯机构：
[Chen, Liyu] C;Cent South Univ, Xiangya Sch Med, Dept Microbiol, Changsha, Hunan, Peoples R China.
关键词：
Campylobacter;Phylogenetic analysis;Ribosomal RNA;Sequence alignment;Paleogenetics;Multiple alignment calculation;Sequence databases;Viral genomics
摘要：
Campylobacter species.are phenotypically diverse in many aspects including host habitats and pathogenicities, which demands comprehensive characterization of the entire Campylobacter genus to study their underlying genetic diversification. Up to now, 34 Campylobacter strains have been sequenced and published in public databases, providing good opportunity to systemically analyze their genomic diversities. In this study, we first conducted genomic characterization, which includes genome-wide alignments, pan-genome analysis, and phylogenetic identification, to depict the genetic diversity of Campylobacter genus. Afterward, we improved the tetranucleotide usage pattern-based naïve Bayesian classifier to identify the abnormal composition fragments (ACFs, fragments with significantly different tetranucleotide frequency profiles from its genomic tetranucleotide frequency profiles) including horizontal gene transfers (HGTs) to explore the mechanisms for the genetic diversity of this organism. Finally, we analyzed the HGTs transferred via bacteriophage transductions. To our knowledge, this study is the first to use single nucleotide polymorphism information to construct liable microevolution phylogeny of 21 Campylobacter jejuni strains. Combined with the phylogeny of all the collected Campylobacter species based on genome-wide core gene information, comprehensive phylogenetic inference of all 34 Campylobacter organisms was determined. It was found that C. jejuni harbors a high fraction of ACFs possibly through intraspecies recombination, whereas other Campylobacter members possess numerous ACFs possibly via intragenus recombination. Furthermore, some Campylobacter strains have undergone significant ancient viral integration during their evolution process. The improved method is a powerful tool for bacterial genomic analysis. Moreover, the findings would provide useful information for future research on Campylobacter genus.
语种：
英文
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Removal and recovery of uranium (VI) from aqueous solutions by immobilized Aspergillus niger powder beads
作者：
Ding, De-Xin* ;Tan, Xiang;Hu, Nan;Li, Guang-Yue;Wang, Yong-Dong;...
期刊：
Bioprocess and Biosystems Engineering ,2012年35(9):1567-1576 ISSN：1615-7591
通讯作者：
Ding, De-Xin
作者机构：
[Li, Guang-Yue; Tan, Yan; Hu, Nan; Tan, Xiang; Ding, De-Xin; Wang, Yong-Dong] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.;[Tan, Yan; Ding, De-Xin] Cent S Univ, Sch Resources & Safety Engn, Changsha 410083, Peoples R China.;[Ding, De-Xin] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 W Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, De-Xin] U;Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, 28 W Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
关键词：
Biosorption;Uranium;Aspergillus niger;Equilibrium;Kinetics
摘要：
The immobilized Aspergillus niger powder beads were obtained by entrapping nonviable A. niger powder into Ca-alginate gel. The effects of pH, contact time, initial uranium (VI) concentration and biomass dosage on the biosorption of uranium (VI) onto the beads from aqueous solutions were investigated in a batch system. Biosorption equilibrium data were agreeable with Langmuir isotherm model and the maximum biosorption capacity of the beads for uranium (VI) was estimated to be 649.4 mg/g at 30 °C. The biosorption kinetics followed the pseudo-second-order model and intraparticle diffusion equation. The variations in enthalpy (26.45 kJ/mol), entropy (0.167 kJ/mol K) and Gibbs free energy were calculated from the experimental data. SEM and EDS analysis indicated that the beads have strong adsorption capability for uranium (VI). The adsorbed uranium (VI) on the beads could be released with HNO3 or HCl. The results showed that the immobilized A. niger powder beads had great potential for removing and recovering uranium (VI) from aqueous solutions. © Springer-Verlag 2012.
语种：
英文
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A core-shell structured nanocomposite material for detection, adsorption and removal of Hg(II) ions in water
作者：
Li, Le;Tang, Shuangyang;Ding, Dexin* ;Hu, Nan;Yang, Shengyuan;...
期刊：
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY ,2012年12(11):8407-8414 ISSN：1533-4880
通讯作者：
Ding, Dexin
作者机构：
[Yang, Shengyuan; Tan, Yan; He, Shuya; Li, Le] Univ S China, Sch Publ Hlth, Hengyang 421001, Peoples R China.;[Tang, Shuangyang] Univ S China, Coll Med, Hengyang 421001, Peoples R China.;[Ding, Dexin; Li, Le; Hu, Nan; Sun, Jing; Wang, Yongdong] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.;[Yang, Shengyuan] Hunan Univ, Coll Chem & Chem Engn, State Key Lab Chemo Biosensing & Chemometr, Changsha 410082, Hunan, Peoples R China.
通讯机构：
[Ding, Dexin] U;Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
关键词：
Fe_3O_4 Nanoparticles;Pyrene;Detection;Adsorption;Removal;Hg(II)
摘要：
In this paper, a core-shell structured nanocomposite material was prepared for the detection, adsorption and removal of Hg(II) ions in aqueous solution. The core was made from Fe<inf>3</inf>O<inf>4</inf> nanoparticles with superparamagnetic behavior and the outer shell was made from amorphous silica modified with pyrene-based sensing-probes. The material could detect and adsorb Hg(II) ions in aqueous solution due to its surface being modified with pyrene-based sensing-probes, and could easily be removed from the solution by magnetic force because of its core being made from magnetic Fe<inf>3</inf>O <inf>4</inf> nanoparticles. This multifunctional core-shell structure was confirmed and characterized by TEM, IR spectra, TGA, XRD and N<inf>2</inf> adsorption/desorption isotherms. Experiments were conducted on its functions of detection, adsorption and removal of Hg(II) ions in aqueous solution. The experimental results showed that this composite material had high sensitivity and unique selectivity to Hg(II), and that it could easily be removed from the solution. Copyright ©2012 American Scientific Publishers.
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英文
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Evaluation of the toxic effect on zebrafish (Danio rerio) exposed to uranium mill tailings leaching solution
作者：
Geng, Fang;Hu, Nan;Zheng, Ji-Fang* ;Wang, Cheng-Lei;Chen, Xin;...
期刊：
Journal of Radioanalytical and Nuclear Chemistry ,2012年292(1):453-463 ISSN：0236-5731
通讯作者：
Zheng, Ji-Fang
作者机构：
[Chen, Xin; Geng, Fang; Zheng, Ji-Fang; Hu, Nan; Wang, Cheng-Lei; Ding, De-Xin; Yu, Jia] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Zheng, Ji-Fang] U;Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.
关键词：
Antioxidant enzyme;MDA;Na + -K + -ATPase;Uranium mill tailings leaching solution;Zebrafish
摘要：
The objective of this study was to evaluate the potential ecological danger and toxic effect of uranium mill tailings leaching solution (UMTLS) on aquatic animals. UMTLS was identified to contain two radioactive elements, nine heavy metal elements, and five non-metallic materials. The acute toxicity test indicated that the 1, 12, 24, 48, 72, 96 h LC 50 values of UMTLS to the zebrafish were 12.1, 7.1, 4.4, 3.8, 3.4, and 2.9%, respectively. In sub-lethal toxicity tests, superoxide dismutase, catalase, Na + -K + -ATPase activities, and malondialdehyde content were respectively determined and analyzed in the zebrafish gill, gonad, muscle, and liver after exposed to four different concentration levels of UMTLS for 7 and 14 days, respectively. The result showed that the most sensitivity of the antioxidant system in zebrafish tissues in UMTLS was gill, and then decreased in gonad, muscle and liver respectively. Na + -K + -ATPase activity in the liver and gonad may be considered as a reference biomarker of UMTLS stress. The data in this study may be valuable that the toxicity of such as the leaching solution of potentially hazardous material was compared with that of each constituent. © 2011 Akadémiai Kiadó.
语种：
英文
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Removal and recovery of uranium from aqueous solution by tea waste
作者：
Ding, De-Xin* ;Liu, Xi-Tao;Hu, Nan;Li, Guang-Yue;Wang, Yong-Dong
期刊：
Journal of Radioanalytical and Nuclear Chemistry ,2012年293(3):735-741 ISSN：0236-5731
通讯作者：
Ding, De-Xin
作者机构：
[Li, Guang-Yue; Hu, Nan; Liu, Xi-Tao; Ding, De-Xin; Wang, Yong-Dong] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.;[Liu, Xi-Tao] Shandong Gold Grp, Jiaojia Gold Mine, Laizhou 264000, Peoples R China.
通讯机构：
[Ding, De-Xin] U;Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
关键词：
Tea waste;Uranium;Radioactive wastewater;Adsorption;Desorption;Kinetic;Adsorption isotherm
摘要：
Experiments on the removal and recovery of U(VI) from aqueous solution by tea waste were conducted. The adsorbent was characterized by scanning electron microscope and energy dispersive spectrometer before and after the adsorption treatment. The removal of U(VI) amounts to 86.80 % at optimum pH 6. The adsorption process reaches its equilibrium in 12 h at 308 K, and the kinetic characteristic can be described by the pseudo-second-order kinetic equation. The amount of adsorption increases from 22.92 to 142.21 mg g−1 with the decrease of tea waste dosage from 100 to 10 mg for solution with an initial uranium concentration of 50 mg L−1. Desorption for the four strippants is higher than 80 %. The equilibrium data are more agreeable with Freundlich isotherm than Langmuir isotherm.
语种：
英文
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The influence of fractal size distribution of covers on radon exhalation from uranium mill tailings
作者：
Tan, Kaixuan* ;Liu, Zehua;Xia, Liangshu;Lv, Junwen;Hu, Hanqiao
期刊：
Radiation Measurements ,2012年47(2):163-167 ISSN：1350-4487
通讯作者：
Tan, Kaixuan
作者机构：
[Liu, Zehua; Lv, Junwen; Tan, Kaixuan; Xia, Liangshu; Hu, Hanqiao] Univ S China, Sch Nucl Resources & Nucl Fuel Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Tan, Kaixuan] U;Univ S China, Sch Nucl Resources & Nucl Fuel Engn, Hengyang 421001, Hunan, Peoples R China.
关键词：
Fractal;Size distribution;Covers;Radon exhalation rate;Uranium mill tailings
摘要：
Tailings produced during mining and milling of uranium ores represent potentially large volumes of low level radioactive materials. A typical environmental problem associated with mill tailings is radon emanation. Covering tailings is widely applied to reduce radon exhalation rate. In this paper, the fractal theories and field covering tests are used to study the fractal characters of size distribution of six types of covering materials, including waste rock, sand, laterite, kaolin, mixture of sand and laterite, and mixture of waste rock and laterite, and their influences on radon exhalation. The size distributions of uranium tailings and the six aforementioned covering materials all exhibit a good fractal structure. The contents of fine grain increase with the increasing value of fractal dimension. The results of field radon measurement show that the radon emanation rate of tailings without covers is 14.7-18.6 Bq/m<sup>2</sup> s. Covering tests were carried out of the six abovementioned covering materials with thickness of 0.4 m, 0.8 m, 1.2 m, 1.6 m and 2.0 m. The results indicate that the application of these materials for cover layers can decrease the radon exhalation rate markedly. The effectiveness of a cover layer in reducing radon exhalation is related to its fractal texture of size distribution. Under the same thickness conditions, the attenuation coefficient of radon exhalation rate increases with the increasing fractal dimension of size distribution of covers. The empirical expressions of the attenuation coefficients in relation to fractal dimension D of size distribution and thickness x of covers is obtained for evaluating the effectiveness of final covers for uranium tailings impoundments. ©2011 Elsevier Ltd. All rights reserved.
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英文
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Studies on adsorption of uranium (VI) from aqueous solution by wheat straw
作者：
Wang, Xiao;Xia, Liangshu* ;Tan, Kaixuan;Zheng, Weina
期刊：
ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY ,2012年31(4):566-576 ISSN：1944-7442
通讯作者：
Xia, Liangshu
作者机构：
[Zheng, Weina; Wang, Xiao] Univ S China, Sch Chem & Chem Engn, Hengyang 421001, Hunan, Peoples R China.;[Tan, Kaixuan; Xia, Liangshu] Univ S China, Sch Nucl Resources & Nucl Fuel Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Xia, Liangshu] U;Univ S China, Sch Nucl Resources & Nucl Fuel Engn, Hengyang 421001, Hunan, Peoples R China.
关键词：
wheat straw;uranium;modified;adsorption;mechanism
摘要：
A fundamental investigation on the removal of uranium from aqueous solutions by wheat straw was conducted in batch conditions. The influence of different experimental parameters such as modified methods, pH, contact time, adsorbent dose, initial concentration, and temperature, on the kinetics of uranium removal was studied. The results showed that the higher adsorption rate of uranium on wheat straw was modified by NaOH. At 303 K and pH was 3.0, the saturation adsorption was up to 1.20 mg/g at approximately 120 min. The uranium uptake was quantitatively evaluated using sorption isotherms and the correlation coefficients showed that the Freundlich model gave a better fit than the Langmuir equation. The process followed a pseudo-second-order kinetics. Scanning electron microscope coupled with Fourier transform infrared analysis for wheat straw, demonstrated that uranium-containing sites existed on the surface structure with hydroxyl, carbonyl, Pi-O and Si=O groups. Copyright © 2011 American Institute of Chemical Engineers (AIChE).
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英文
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Preparation of ethylenediamine-modified magnetic chitosan complex for adsorption of uranyl ions
作者：
Wang, Jing-song* ;Peng, Rui-ting;Yang, Jin-hui;Liu, Yao-chi;Hu, Xin-jiang
期刊：
Carbohydrate Polymers ,2011年84(3):1169-1175 ISSN：0144-8617
通讯作者：
Wang, Jing-song
作者机构：
[Wang, Jing-song; Peng, Rui-ting; Yang, Jin-hui] Univ S China, Sch Urban Construct, Hengyang 421001, Hunan, Peoples R China.;[Wang, Jing-song; Peng, Rui-ting; Yang, Jin-hui] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Hunan, Peoples R China.;[Liu, Yao-chi] Cent S Univ, Sch Chem & Chem Engn, Changsha 410083, Hunan, Peoples R China.;[Hu, Xin-jiang] Hunan Univ, Coll Environm Sci & Engn, Changsha 410082, Hunan, Peoples R China.
通讯机构：
[Wang, Jing-song] U;Univ S China, Sch Urban Construct, Hengyang 421001, Hunan, Peoples R China.
关键词：
Adsorption;Chitosan;Magnetic;Modified;Uranyl ions
摘要：
Ethylenediamine-modified magnetic chitosan (EMMC) complex was developed as a novel magnetic adsorbent for the removal of uranyl ions. XRD spectrum indicated that the magnetic particles were pure Fe3O4 with a spinel structure, and the binding of chitosan did not result in a phase change. IR analysis demonstrated that Fe3O4 particles were successfully bounded by chitosan and more amino groups appeared in the EMMC samples. EMMC was found to be quite efficient to adsorb uranyl ions at pH 2-7. Equilibrium was established within 30 min, and the kinetic experimental data properly correlated with the pseudo-second-order kinetic model, indicating that the chemical sorption is the rate-limiting step. The adsorption data could be best interpreted by the Sips model with a maximum adsorption capacity of 82.83 mg U g-1. The EMMC can be regenerated with high efficiency, suggesting that this adsorbent is satisfactory to reuse uranyl ions. © 2011 Elsevier Ltd. All rights reserved.
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英文
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Investigation and modeling on fatigue damage evolution of rock as a function of logarithmic cycle
作者：
Xiao, Jian-Qing;Feng, Xia-Ting* ;Ding, De-Xin;Jiang, Fu-Liang
期刊：
International Journal for Numerical and Analytical Methods in Geomechanics ,2011年35(10):1127-1140 ISSN：0363-9061
通讯作者：
Feng, Xia-Ting
作者机构：
[Xiao, Jian-Qing; Feng, Xia-Ting] Chinese Acad Sci, State Key Lab Geomech & Geotech Engn, Inst Rock & Soil Mech, Wuhan 430071, Peoples R China.;[Xiao, Jian-Qing] Anyang Normal Univ, Sch Civil Engn & Architecture, Anyang 455002, Peoples R China.;[Jiang, Fu-Liang; Xiao, Jian-Qing; Ding, De-Xin] Univ S China, Sch Nucl Resource & Nucl Fuel Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Feng, Xia-Ting] C;Chinese Acad Sci, State Key Lab Geomech & Geotech Engn, Inst Rock & Soil Mech, Wuhan 430071, Peoples R China.
关键词：
rock;fatigue damage;cyclic loading;inverted-S model
摘要：
The fatigue damage behavior of granite under constant and variable amplitude loadings is studied. The experimental analysis reveals that there is a three-stage law for the fatigue damage evolution as a function of absolute or relative cycle and the inverted-S damage model proposed by the author, in this case, is capable of representing the damage behavior of rock. However, when the logarithmic cycle is considered, there are only two stages, i.e. steady and accelerated stages and the fatigue damage evolution greatly depends on the properties of rock and stress level. Accordingly, the fatigue damage evolution curves have been categorized into three types. Then, the effect of maximum stress, amplitude and fatigue initial damage on the damage evolution of rock is investigated. The analysis reveals that the damage evolution greatly depends on these influencing factors. The fatigue life decreases with the increase in the maximum stress, amplitude and fatigue initial damage due to the decrease in the proportion of the first stage to the whole fatigue process and the increase in the damage rate in the first stage. Meanwhile, a linear-exponential formula is used to model the fatigue damage behavior of rock subjected to cyclic loading. This damage model is superior to the inverted-S damage model in the convenience of establishment of critical instability point. The physical meanings of its constants have been illuminated and the applicability of this model to constant and variable amplitude cyclic loading explored. The fitting results for the test data show that this damage model can properly represent the fatigue damage behavior of rock. Copyright © 2010 John Wiley & Sons, Ltd.
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英文
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Screening of plant species for phytoremediation of uranium, thorium, barium, nickel, strontium and lead contaminated soils from a uranium mill tailings repository in South China
作者：
Li, Guang-yue;Hu, Nan;Ding, De-xin* ;Zheng, Ji-fang;Liu, Yu-long;...
期刊：
Bulletin of Environmental Contamination and Toxicology ,2011年86(6):646-652 ISSN：0007-4861
通讯作者：
Ding, De-xin
作者机构：
[Li, Guang-yue; Liu, Yu-long; Nie, Xiao-qin; Hu, Nan; Zheng, Ji-fang; Ding, De-xin; Wang, Yong-dong] Univ S China, Key Discipline Lab Natl Def Biol Technol Uranium, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, De-xin] U;Univ S China, Key Discipline Lab Natl Def Biol Technol Uranium, Hengyang 421001, Hunan, Peoples R China.
关键词：
Uranium;Thorium;Hyperaccumulator;Mill tailings;Phytoremediation factor
摘要：
The concentrations of uranium, thorium, barium, nickel, strontium and lead in the samples of the tailings and plant species collected from a uranium mill tailings repository in South China were analyzed. Then, the removal capability of a plant for a target element was assessed. It was found that Phragmites australis had the greatest removal capabilities for uranium (820 μg), thorium (103 μg) and lead (1,870 μg). Miscanthus floridulus had the greatest removal capabilities for barium (3,730 μg) and nickel (667 μg), and Parthenocissus quinquefolia had the greatest removal capability for strontium (3,920 μg). In this study, a novel coefficient, termed as phytoremediation factor (PF), was proposed, for the first time, to assess the potential of a plant to be used in phytoremediation of a target element contaminated soil. Phragmites australis has the highest PFs for uranium (16.6), thorium (8.68), barium (10.0) and lead (10.5). Miscanthus floridulus has the highest PF for Ni (25.0). Broussonetia papyrifera and Parthenocissus quinquefolia have the relatively high PFs for strontium (28.1 and 25.4, respectively). On the basis of the definition for a hyperaccumulator, only Cyperus iria and Parthenocissus quinquefolia satisfied the criteria for hyperaccumulator of uranium (36.4 μg/g) and strontium (190 μg/g), and could be the candidates for phytoremediation of uranium and strontium contaminated soils. The results show that the PF has advantage over the hyperaccumulator in reflecting the removal capabilities of a plant for a target element, and is more adequate for assessing the potential of a plant to be used in phytoremediation than conventional method. © 2011 Springer Science+Business Media, LLC.
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英文
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Production of zinc and lead concentrates from lean oxidized zinc ores by alkaline leaching followed by two-step precipitation using sulfides
作者：
Liu, Qing* ;Zhao, Youcai;Zhao, Guodong
期刊：
Hydrometallurgy ,2011年110(1-4):79-84 ISSN：0304-386X
通讯作者：
Liu, Qing
作者机构：
[Liu, Qing] Univ S China, Sch Urban Construct, Hengyang 421001, Peoples R China.;[Zhao, Youcai; Liu, Qing] Tongji Univ, State Key Lab Pollut Control & Resource Reuse, Shanghai 200092, Peoples R China.;[Zhao, Guodong] Univ S China, Sch Nucl Resources & Nucl Fuel Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Liu, Qing] U;Univ S China, Sch Urban Construct, Hengyang 421001, Peoples R China.
关键词：
Alkaline;Concentrate;Precipitation;Sodium sulfide
摘要：
An integrated hydrometallurgical process for the production of zinc and lead concentrates from lean oxidized zinc ores by alkaline leaching, followed by two-step sulfide precipitation of lead and zinc sulfides, is developed. The lean zinc oxidized ore was firstly ground to a size below 0.2 mm, followed by alkaline leaching at 90 °C for 120 min in NaOH solution, in which both zinc and lead are effectively extracted. Lead concentrates were then highly selectively and quantitatively produced from the leach solution by adding sodium sulfide as precipitant. Zinc concentrates were obtained in the same way from the Pb-free solution. Optimum conditions of lead precipitation were found to be 1.8 Na<inf>2</inf>S•9H<inf>2</inf>O/Pb weight ratio, 90 °C, 60 min and those for zinc precipitation were 2.4 Na<inf>2</inf>S•9H<inf>2</inf>O/Zn weight ratio, 90 °C, 180 min. Finally, a scale-up experiment was carried out and found that the lead and zinc total extraction both reached above 80% calculated from the ores and the quality of lead and zinc concentrates can meet industrial requirements for roasting processes. Meanwhile, it was found that the loss of NaOH is negligible and the main consumption of chemicals was that of sodium sulfide. ©2011 Elsevier Inc. All rights reserved.
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英文
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Removal of Uranium From Aqueous Solution by Chitosan and Ferrous Ions
作者：
Wang, Jing-song* ;Bao, Zheng-lei;Chen, Si-guang;Yang, Jin-hui
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.
会议论文集名称：
Proceedings of the 18th International Conference on Nuclear Engineering
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]
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英文
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Fatigue damage variable and evolution of rock subjected to cyclic loading
作者：
Xiao, Jian-Qing;Ding, De-Xin* ;Jiang, Fu-Liang;Xu, Gen
期刊：
International Journal of Rock Mechanics and Mining Sciences ,2010年47(3):461-468 ISSN：1365-1609
通讯作者：
Ding, De-Xin
作者机构：
[Jiang, Fu-Liang; Xiao, Jian-Qing; Ding, De-Xin] Univ S China, Sch Nucl Resources & Nucl Fuel Engn, Hengyang 421001, Peoples R China.;[Xiao, Jian-Qing] Chinese Acad Sci, Inst Rock & Soil Mech, State Key Lab Geomech & Geotech Engn, Wuhan 430071, Peoples R China.;[Xu, Gen; Jiang, Fu-Liang; Xiao, Jian-Qing] Cent S Univ, Sch Resources & Safety Engn, Changsha 410083, Peoples R China.
通讯机构：
[Ding, De-Xin] U;Univ S China, Sch Nucl Resources & Nucl Fuel Engn, Hengyang 421001, Peoples R China.
语种：
英文
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Three-dimensional thermoluminescence spectra of different origin quartz from Altay Orogenic belt, Xinjiang, China
作者：
Tan, Kaixuan* ;Liu, Zehua;Zeng, Sheng;Liu, Yan;Xie, Yanshi;...
期刊：
Radiation Measurements ,2009年44(5-6):529-533 ISSN：1350-4487
通讯作者：
Tan, Kaixuan
作者机构：
[Liu, Yan; Zeng, Sheng; Liu, Zehua; Xie, Yanshi; Tan, Kaixuan] Univ S China, Sch Nucl Resource & Safety Engn, Hengyang 421001, Hunan, Peoples R China.;[Rieser, Uwe] Victoria Univ Wellington, Sch Geog Environm & Earth Sci, Wellington, New Zealand.
通讯机构：
[Tan, Kaixuan] U;Univ S China, Sch Nucl Resource & Safety Engn, Hengyang 421001, Hunan, Peoples R China.
会议名称：
12th International Conference on Luminescence and Electron Spin Resonance
会议时间：
SEP 18-22, 2008
会议地点：
Peking Univ, Beijing, PEOPLES R CHINA
会议主办单位：
[Tan, Kaixuan;Liu, Zehua;Zeng, Sheng;Liu, Yan;Xie, Yanshi] Univ S China, Sch Nucl Resource & Safety Engn, Hengyang 421001, Hunan, Peoples R China.^[Rieser, Uwe] Victoria Univ Wellington, Sch Geog Environm & Earth Sci, Wellington, New Zealand.
关键词：
3-D spectra;Altay orogenic belt;Quartz;Thermoluminescence
摘要：
Three-dimensional thermoluminescence spectra are measured for different types of geological origin quartz from the Altay orogenic belt, northern Xinjiang, China. The results show striking differences which appear to be characteristic of their geological origin. Granitic quartz is dominated by emission bands at 420-430 nm, 550-560 nm, at a temperature of 170 °C. Pegmatite quartz is characterized by an intense 480 nm emission band at 170 °C. Volcanic quartz has exclusive UV (340-360 nm) and violet (410-430 nm) emission bands. Hydrothermal quartz exhibits very different TL spectral characteristics because of different hydrothermal activity and mineralization. Only one TL peaks at 485 nm/170 °C was observed in sedimentary quartz. An intense 730 nm emission band observed at 170 °C considered generally to be characteristics of feldspar was observed in quartz from granite and hydrothermal Au-bearing quartz. This TL peak is probably related to the centre of [FeO<inf>4</inf>]<sup>0</sup> on an Si site. All samples show an intense 990-1000 nm emission band at 330 °C. Identical types of quartz formed in different regions or different geological and tectonic settings can also exhibit striking differences in TL spectra. ©2009 Elsevier Ltd. All rights reserved.
语种：
英文
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Metal pollution in Huayuan river in Hunan province in China by manganese sulphate waste residue
作者：
Hu, Nan;Zheng, Ji-Fang* ;Ding, De-Xin;Liu, Jun;Yang, Lu-Qing;...
期刊：
Bulletin of Environmental Contamination and Toxicology ,2009年83(4):583-590 ISSN：0007-4861
通讯作者：
Zheng, Ji-Fang
作者机构：
[Li, Guang-Yue; Liu, Yu-Long; Yin, Jie; Zheng, Ji-Fang; Yang, Lu-Qing; Hu, Nan; Ding, De-Xin; Liu, Jun; Wang, Yong-Dong] Univ S China, Key Discipline Lab Natl Def Biol Technol Uranium, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Zheng, Ji-Fang] U;Univ S China, Key Discipline Lab Natl Def Biol Technol Uranium, Hengyang 421001, Hunan, Peoples R China.
关键词：
Huayuan River;Manganese sulphate waste residue;Sediment;Speciation;Water pollution
摘要：
The Huayuan River in Hunan Province in China is subject to ongoing mining activity with Mn extraction. In this study, the level and environmental significance of metals (including Mn, Cd, Pb, Cu, Zn, Ni and Fe) concentrations in the surface water and river sediments have been investigated along a 187 km reach of the Huayuan River. Using the X-ray fluorescence (XRF) analysis, we analyzed the characterization of metals in manganese sulphate waste residue (MSWR) deposited along the bank of Huayuan River. The speciation of metals in both sediment and MSWR was established using the BCR-three step sequential extraction procedure. In the water samples, the average concentrations of Mn, Cd and Pb exceeded the acceptable concentrations for drinking water in the WHO Guidelines for drinking water quality, Vol. 1, Recommendations, Geneva (2004) and Chinese (GB 5749-2006) guidelines, respectively. The average concentrations of Mn, Cd, Pb and Zn in the river sediments were found to be considerably higher than the corresponding world average shale values. The percentages of Cd (31.4%), Mn (31.1%), Zn (12.8%) and Pb (8.1%) associated with exchangeable and weak acid fraction in the sediments were higher than other metals. Mn (5.81%), Zn (0.208%), Pb (0.0292%) and Cd (0.0113%) were identified in MSWR by XRF analysis. The percentages of Mn, Cd, Zn and Pb associated with the exchangeable and weak acid soluble fraction in MSWR were 41.9%, 31.1%, 23.8% and 9.8%, respectively. The peak solute and sediment-bound metal concentrations were found at the sites of MSWR deposited along the bank of Huayuan River. The results suggested that MSWR deposited along the bank may have a closely relation with the metal pollution of Huayuan River. The results obtained may be useful to assess both short and long-term environmental impact of the MSWR deposited activities and support decisions for a future remediation of this river. © 2009 Springer Science+Business Media, LLC.
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英文
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Inverted S-shaped model for nonlinear fatigue damage of rock
作者：
Xiao, Jian-Qing* ;Ding, De-Xin;Xu, Gen;Jiang, Fu-Liang
期刊：
International Journal of Rock Mechanics and Mining Sciences ,2009年46(3):643-648 ISSN：1365-1609
通讯作者：
Xiao, Jian-Qing
作者机构：
[Jiang, Fu-Liang; Xiao, Jian-Qing; Ding, De-Xin] Univ S China, Sch Nucl Resources & Safety Engn, Hengyang 421001, Peoples R China.;[Xu, Gen; Jiang, Fu-Liang; Xiao, Jian-Qing] Cent S Univ, Sch Resources & Safety Engn, Changsha 410083, Peoples R China.;[Xiao, Jian-Qing] Univ S China, Sch Math & Phys, Hengyang 421001, Peoples R China.
通讯机构：
[Xiao, Jian-Qing] U;Univ S China, Sch Math & Phys, Hengyang 421001, Peoples R China.
语种：
英文
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Removal of SO_4~(2-), uranium and other heavy metal ions from simulated solution by sulfate reducing bacteria
作者：
Wang Qing-liang* ;Ding De-xin;Hu E-ming;Yu Run-lan;Qiu Guan-zhou
期刊：
中国有色金属学报(英文版) ,2008年18(6):1529-1532 ISSN：1003-6326
通讯作者：
Wang Qing-liang
作者机构：
[Wang Qing-liang; Yu Run-lan; Qiu Guan-zhou] Cent S Univ, Sch Minerals Proc & Bioengn, Changsha 410083, Peoples R China.;[Ding De-xin; Wang Qing-liang; Hu E-ming] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
通讯机构：
[Wang Qing-liang] C;Cent S Univ, Sch Minerals Proc & Bioengn, Changsha 410083, Peoples R China.
会议名称：
24th International Mineral Processing Congress (IMPC)
会议时间：
SEP 24-28, 2008
会议地点：
Beijing, PEOPLES R CHINA
会议主办单位：
[Wang Qing-liang;Yu Run-lan;Qiu Guan-zhou] Cent S Univ, Sch Minerals Proc & Bioengn, Changsha 410083, Peoples R China.^[Wang Qing-liang;Ding De-xin;Hu E-ming] Univ S China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.
关键词：
sulfate reducing bacteria;in-situ leaching of uranium;radioactively contaminated groundwater;bioremediation
摘要：
In the case of in-situ leaching of uranium, the primitive geochemical environment for groundwater is changed since leachant is injected into the water bearing uranium deposit. This increases the concentration of SO_4~(2-), uranium and other heavy metal ions and results in the groundwater contamination. The effects of pH values of the simulated solution on the reduction of SO_4~(2-) and the removal of uranium and other heavy metal ions by sulfate reducing bacteria(SRB) were studied. The results show that, when the pH value of the simulated solution is about 8, the reduction rate of SO_4~(2-) by SRB and the removal rate of uranium, Mn~(2+), Zn~(2+), Pb~(2+) and Fe~(2+) will reach their highest values. A bioremediation technique for remediation of groundwater in in-situ leaching uranium mine can be developed.
语种：
英文
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Nontrivial solutions of discrete elliptic boundary value problems
作者：
Tang, Hengsheng;Luo, Wei;Li, Xu;Ma, Manjun*
期刊：
Computers & Mathematics with Applications ,2008年55(8):1854-1860 ISSN：0898-1221
通讯作者：
Ma, Manjun
作者机构：
[Tang, Hengsheng; Ma, Manjun] Nanhua Univ, Dept Math & Phys, Hengyang 421001, Hunan, Peoples R China.;[Tang, Hengsheng] Hunan Univ, Dept Appl Math, Changsha 410082, Hunan, Peoples R China.;[Luo, Wei] Hunan Inst Technol, Fundamental Dept, Hengyang 421001, Hunan, Peoples R China.;[Li, Xu] Nanhua Univ, Dept Nucl Resource & Safety Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ma, Manjun] N;Nanhua Univ, Dept Math & Phys, Hengyang 421001, Hunan, Peoples R China.
关键词：
discrete elliptic boundary value problems;nontrivial solutions;existence;variational method;Mountain Pass Theorem;PARTIAL DIFFERENCE-EQUATIONS;EXISTENCE
摘要：
This paper aims to show the existence of nontrivial solutions for discrete elliptic boundary value problems by using the "Mountain Pass Theorem". Some conditions are obtained for discrete elliptic boundary value problems to have at least two nontrivial solutions. The results obtained improve the consequences of the known literature [Guang Zhang, Existence of nontrivial solutions for discrete elliptic boundary value problems, Numer. Methods Partial Differential Equations 22 (6) (2006) 1479-1488]. (C) 2007 Elsevier Ltd. All rights reserved.
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英文
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