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Coexistence Theory of Slag Structure and Its Application to Calculation of Oxidizing Capability of Slag Melts 被引量:29
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作者 ZHANG Jian 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2003年第1期1-10,共10页
The coexistence theory of slag structure and it's application to calculation of the oxidizing capabilities of slag melts is described. It is shown that the law of mass action can be widely applied to the calculati... The coexistence theory of slag structure and it's application to calculation of the oxidizing capabilities of slag melts is described. It is shown that the law of mass action can be widely applied to the calculation of oxidizing capabilities of slag melts in combination with the coexistence theory of slag structure.For slag melts containing basic oxides FeO and MnO, their oxidizing capabilities can be expressed by N Fe tO =N FeO +6N Fe 2O 3 , while for slag melts containing basic oxides CaO, MgO, etc., in addition to FeO and MnO, their oxidizing capabilities can be given as N Fe tO =N FeO +6N Fe 2O 3 +8N Fe 3O 4 . 展开更多
关键词 oxidizing capability coexistence theory slag structure ACTIVITY mass action concentration
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Molybdenite-limestone oxidizing roasting followed by calcine leaching with ammonium carbonate solution 被引量:9
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作者 Qiu-sheng ZHOU Wei-tao YUN +4 位作者 Jun-tao XI Xiao-bin LI Tian-gui QI Gui-hua LIU Zhi-hong PENG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第7期1618-1626,共9页
Oxidizing roasting of molybdenite with lime can significantly reduce SO2pollution compared with the traditional roastingwithout lime.However,the calcine is subsequently leached by sulfuric acid,resulting in serious eq... Oxidizing roasting of molybdenite with lime can significantly reduce SO2pollution compared with the traditional roastingwithout lime.However,the calcine is subsequently leached by sulfuric acid,resulting in serious equipment corrosion and abundantnon-recyclable CaSO4slag.In this work,a novel process,in which the molybdenite was roasted with CaCO3followed by(NH4)2CO3solution leaching,was proposed to improve the art of lime roasting-sulfuric acid leaching.Oxidizing roasting of molybdenite withCaCO3was investigated through thermodynamic calculation,thermogravimetric analysis and roasting experiments.The results showthat the products of the oxidizing reaction of MoS2in the presence of CaCO3and O2are CaSO4,CaMoO4and CO2at573-1000K.The MoS2conversion rate achieves approximately99%and the sulfur-retained rate attains approximately95%with aCaCO3-to-MoS2molar ratio of3.6at500°C for1h by adding5%mineralizer A(mass fraction).The leaching results show that theleaching rate of Mo reaches98.2%at85°C for7h with a(NH4)2CO3concentration of600g/L and a liquid-solid ratio of10mL/g.The results presented are potential to develop a novel cleaner technique for ammonium molybdate production. 展开更多
关键词 MOLYBDENITE LIMESTONE ammonium carbonate oxidizing roasting LEACHING
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Impact of Long-Term Fertilization on Community Structure of Ammonia Oxidizing and Denitrifying Bacteria Based on amoA and nirK Genes in a Rice Paddy from Tai Lake Region,China 被引量:9
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作者 JIN Zhen-jiang LI Lian-qing +3 位作者 LIU Xiao-yu PAN Gen-xing Qaiser Hussein LIU Yong-zhuo 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第10期2286-2298,共13页
Ammonia oxidizing (AOB) and denitrifying bacteria (DNB) play an important role in soil nitrogen transformation in natural and agricultural ecosystems. Effects of long-term fertilization on abundance and community ... Ammonia oxidizing (AOB) and denitrifying bacteria (DNB) play an important role in soil nitrogen transformation in natural and agricultural ecosystems. Effects of long-term fertilization on abundance and community composition of AOB and DNB were studied with targeting ammonia monooxygenase (amoA) and nitrite reductase (nirK) genes using polymerase chain reaction- denaturing gradient gel electrophoresis (PCR-DGGE) and real-time PCR, respectively. A field trial with different fertilization treatments in a rice paddy from Tai Lake region, centre East China was used in this study, including no fertilizer application (NF), balanced chemical fertilizers (CF), combined organic/inorganic fertilizer of balanced chemical fertilizers plus pig manure (CFM), and plus rice straw return (CFS). The abundances and riehnesses of amoA and nirK were increased in CF, CFM and CFS compared to NF. Principle component analysis of DGGE profiles showed significant difference in nirK and amoA genes composition between organic amended (CFS and CFM) and the non-organic amended (CF and NF) plots. Number of amoA copies was significantly positively correlated with normalized soil nutrient richness (NSNR) of soil organic carbon (SOC) and total nitrogen (T-N), and that of nirK copies was with NSNR of SOC, T-N plus total phosphorus. Moreover, nitrification potential showed a positive correlation with SOC content, while a significantly lower denitrification potential was found under CFM compared to under CFS. Therefore, SOC accumulation accompanied with soil nutrient richness under long-term balanced and organic/inorganic combined fertilization promoted abundance and diversity of AOB and DNB in the rice paddy. 展开更多
关键词 long-term fertilization ammonia oxidizing bacteria denitrifying bacteria abundance rice paddy
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Effect of Selenium on Root Oxidizing Ability and Yield of Rice under Ferrous Stress 被引量:10
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作者 QIXin LIUYuan-ying SONGTian-xing 《Journal of Northeast Agricultural University(English Edition)》 CAS 2004年第1期19-22,共4页
To study the effects of selenium on root oxidizing ability and yield of rice under ferrous stress, a pot culture experiment was conducted, the activity of glutathione peroxidase (GSH-Px) and the concentration of malon... To study the effects of selenium on root oxidizing ability and yield of rice under ferrous stress, a pot culture experiment was conducted, the activity of glutathione peroxidase (GSH-Px) and the concentration of malonaldelyde (MDA) were determined. The root oxidizing ability and yield characters of rice were examined. Results showed that appropriate amount of Se enhanced the activity of glutathione peroxidase and the oxidizing ability of rice roots significantly, reduced the concentration of MDA, increased 1000-grain weight of rice, F = 26.96**, decreased empty and blighted grain rate, increased the rice yield, F = 11.53**, and enhanced the rice resistance under ferrous stress. 展开更多
关键词 SELENIUM ferrous stress rice oxidizing ability of root YIELD
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Effects of Selenium on Lipid Peroxidation and Oxidizing Ability of Rice Roots under Ferrous Stress 被引量:6
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作者 PENG Xian long,LIU Yuan ying, LUO Sheng guo,JIANG Bai wen YU cai lian (Faculty of Natural Resources and Environmental Science, Northeast Agricultural University, Harbin 150030,PRC) 《Journal of Northeast Agricultural University(English Edition)》 CAS 2002年第1期9-15,共7页
Water culture experiment was conducted to study the effects of selenium(Se) on glutathione peroxidase(GSH-Px) activity,reduced glutathione(GSH) concentration and the accumulation of malonaldehyde(MDA),the product of l... Water culture experiment was conducted to study the effects of selenium(Se) on glutathione peroxidase(GSH-Px) activity,reduced glutathione(GSH) concentration and the accumulation of malonaldehyde(MDA),the product of lipid peroxidation in rice seedling,as well as the effect of se on oxidizing ability of roots under ferrous stress.Results showed that appropriate amount of se significantly increased GSH-Px activity in rice leaves,F=5.5 *,enhanced the amount of GSH and oxidizing ability of roots and reduced the concentration of MDA,F=4.9 *.Compared with Se0+Fe treatment,Se treatments increased the dry matter weight of rice seedling from 10.06% to 10.43%,F=4.09 *. 展开更多
关键词 SELENIUM lipid peroxidation RICE oxidizing ability of roots reduced glutathione
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Optimization of Fermentation Media for Enhancing Nitrite-oxidizing Activity by Artificial Neural Network Coupling Genetic Algorithm 被引量:2
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作者 罗剑飞 林炜铁 +1 位作者 蔡小龙 李敬源 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2012年第5期950-957,共8页
Two artificial intelligence techniques, artificial neural network and genetic algorithm, were applied to optimize the fermentation medium for improving the nitrite oxidization rate of nitrite oxidizing bacteria. Exper... Two artificial intelligence techniques, artificial neural network and genetic algorithm, were applied to optimize the fermentation medium for improving the nitrite oxidization rate of nitrite oxidizing bacteria. Experiments were conducted with the composition of medium components obtained by genetic algorithm, and the experimental data were used to build a BP (back propagation) neural network model. The concentrations of six medium components were used as input vectors, and the nitrite oxidization rate was used as output vector of the model. The BP neural network model was used as the objective function of genetic algorithm to find the optimum medium composition for the maximum nitrite oxidization rate. The maximum nitrite oxidization rate was 0.952 g 2 NO-2-N·(g MLSS)-1·d-1 , obtained at the genetic algorithm optimized concentration of medium components (g·L-1 ): NaCl 0.58, MgSO 4 ·7H 2 O 0.14, FeSO 4 ·7H 2 O 0.141, KH 2 PO 4 0.8485, NaNO 2 2.52, and NaHCO 3 3.613. Validation experiments suggest that the experimental results are consistent with the best result predicted by the model. A scale-up experiment shows that the nitrite degraded completely after 34 h when cultured in the optimum medium, which is 10 h less than that cultured in the initial medium. 展开更多
关键词 BP neural network genetic algorithm OPTIMIZATION nitrite oxidization rate nitrite-oxidizing bacteria
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STUDIES ON TBP-NO_x——A NEW OXIDIZING AGENT PREPARED FROM NITROGEN OXIDES 被引量:1
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作者 Shen Shong ZHANG Ren Zhong QIAO +1 位作者 Qing Zhi ZHANG Fu Gui LU 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第11期877-878,共2页
Nitrogen oxides(NO_2 and NO)are absorbed by tributyl phosphorate(TBP)to fom a new complex mixture of TBP-NO_x. which is used as a selective oddizing agent to oxidize benzylalcohols to corresponding sldehydes or ketone... Nitrogen oxides(NO_2 and NO)are absorbed by tributyl phosphorate(TBP)to fom a new complex mixture of TBP-NO_x. which is used as a selective oddizing agent to oxidize benzylalcohols to corresponding sldehydes or ketones In high yield. In the reaction process, nitrogen oxides are llberated mildly and mainly reduced to nitrogen, while tributyl phosphorate is recovered end recycled. 展开更多
关键词 NO 目血 A NEW oxidizing AGENT PREPARED FROM NITROGEN OXIDES STUDIES ON TBP-NO_x AGENT TBP
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Communities and Quantitative Analysis of Ammonia-oxidizing Organisms in Pearl River Estuary Sediments
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作者 陈金全 郑燕平 +1 位作者 姜丽晶 王风平 《Agricultural Science & Technology》 CAS 2012年第10期2080-2083,2087,共5页
[Objective] This study aimed to investigate the abundance and composition of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in Pearl River Estuary sediment.[Method] Firstly,the amoA gene library was construc... [Objective] This study aimed to investigate the abundance and composition of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in Pearl River Estuary sediment.[Method] Firstly,the amoA gene library was constructed;then based on that,the content and diversity of amoA genes of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in Pearl River Estuary sediment were detected by using quantitative real-time polymerase chain reaction(Q-PCR).[Result] The results of Q-PCR presented that ammonia-oxidizing archaea(AOA) were more abundant than ammonia-oxidizing bacteria(AOB) in the top of sediment cores,with ratios of AOA to AOB of 22 and 9 at the two sites.It suggested that ammonia-oxidizing archaea may play more important roles than ammonia-oxidizing bacteria in the process of ammonia oxidation in the Pearl River Estuary sediment.The phylogenetic tree based on amoA gene sequences revealed that the amoA sequences of both AOA and AOB shared high similarity with the clones from uncultured environment.In the top sediment layer at site Q7,AOB amoA-like gene sequences were dominated by Nitrosomonas-like sequence types,which could be classified into five groups(clusters A,B,C,D and E).Cluster A accounted for 72.1% of the library.In the top sediment layer,the AOA amoA gene fell into two groups "water column/sediment" cluster(52.2%) and "soil/sediment" cluster(47.8%).But in the bottom sediment layer of Q7,most of the AOA amoA sequences(93.3%) fell into "soil/sediment" cluster,and a little part(6.7%) fell into the "water/sediment" cluster.In addition,the total amount of amoA genes in the bottom sediment was higher than that in top sediment.[Conclusion] This study helps to realize the cycle of nitrogen in Pearl River Estuary Region,and thus to provide theoretical support for the treatment of nitrogen eutrophication. 展开更多
关键词 Pearl River Estuary sediment Ammonia oxidation amoA gene Q-PCR
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Oxidizing Capability of Refining Slags Containing BaO
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作者 Gang Lu, Guoguang Cheng, Bo Song, Pei Zhao (Metallurgy School, University of Science and Technology Beijing, Beijing 100083, China) 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2000年第4期251-255,共5页
According to the coexistence theory of slag structure melts, the oxidizing capability of the refining slag CaO-MgO-FeO- A12O3SiO2 is studied and the relationship between the mass action concentration of FeO (NFeO) and... According to the coexistence theory of slag structure melts, the oxidizing capability of the refining slag CaO-MgO-FeO- A12O3SiO2 is studied and the relationship between the mass action concentration of FeO (NFeO) and the activity of FetO (αFetO) for this slag is found to be as NFeo=0.656 1 αFetO. Furthermore, the calculating model of oxidizing capability of the refining slag BaO-CaO-MgO- FeOA12O3-SiO2 is established. A satisfactory result is obtained when using the above oxidizing capability relationship to calculate the desulphurizing capability of such refining BaO-slags. 展开更多
关键词 secondary refining slag oxidizing ability calculating model Metallurgy
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The Influence of associations of hydrocarbon oxidizing microorganisms to the microbial cenosis and oil destruction in soil
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作者 Svetlana A. Aitkeldieva Elmira R. Faizulina +5 位作者 Askar A. Kurmanbaev Olga N. Auezova Zhanat А. Baigonusova Larisa G. Tatarkina Tatiana Sh. Zaitova Amankeldy K. Sadanov 《Natural Science》 2012年第10期784-788,共5页
Mesocosms experiments were used to study the influence of associations of hydrocarbon oxidizing microorganisms on the microbial cenosis and oil destruction in soil. The introduction of active oil oxidizing microorgani... Mesocosms experiments were used to study the influence of associations of hydrocarbon oxidizing microorganisms on the microbial cenosis and oil destruction in soil. The introduction of active oil oxidizing microorganisms associations into the soil purify of soil from oil to 59.8% - 63.8% after 2 months with 5% oil content and with 10% to 49.2% - 55.6%. As a result of oil destruction there was enlarging of the number of all investigated groups of microorganisms. 展开更多
关键词 OIL oxidizing MICROORGANISMS BIOREMEDIATION Associations of HYDROCARBON oxidizing MICROORGANISMS OIL Polluted Soils
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Studies on the Absorption of NO_2 by Polyethylene Glycol and the Oxidizing Properties of the Resulting Absorbent Product
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作者 Xue Sen FAN Qing Zhi ZHANG +1 位作者 Xin Ying ZRANG Sen Song ZHANG (Department of Chemistry, Henan Normal University, Xinxiang, 453002) 《Chinese Chemical Letters》 SCIE CAS CSCD 1997年第9期747-748,共2页
PEG (Polyethylene glycol average molecular weight 300) is used as absorbent of NO2. The absorption efficiency is found to reach up to 97%. The absorbing product, PEG NO2, can be used to cleave benzyl ethers mildly a... PEG (Polyethylene glycol average molecular weight 300) is used as absorbent of NO2. The absorption efficiency is found to reach up to 97%. The absorbing product, PEG NO2, can be used to cleave benzyl ethers mildly and selectively to benzaldehyde and corresponding fatty alcohols, showing that PEG is a valuable oxidizing agent of benzyl ethers. As a carrier of NO2.PEG can be recovered and utilized repeatedly after the oxidation. 展开更多
关键词 NO Studies on the Absorption of NO2 by Polyethylene Glycol and the oxidizing Properties of the Resulting Absorbent Product PEG
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Elimination of 1,2-dichloroethane over(Ce,Cr)_x O_2/Nb_2O_5 catalysts: synergistic performance between oxidizing ability and acidity 被引量:11
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作者 Jie Wan Peng Yang +1 位作者 Xiaolin Guo Renxian Zhou 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第7期1100-1108,共9页
A series of(Ce,Cr)xO2/Nb2O5 catalysts with different(Ce,Cr)xO2 to Nb2O5 mass ratios were synthesized by the deposition-precipitation method for use in deep catalytic oxidation of 1,2-dichloroethane(DCE), which is one ... A series of(Ce,Cr)xO2/Nb2O5 catalysts with different(Ce,Cr)xO2 to Nb2O5 mass ratios were synthesized by the deposition-precipitation method for use in deep catalytic oxidation of 1,2-dichloroethane(DCE), which is one of the typical chlorinated volatile organic compound pollutants. The textural properties were characterized by X-ray diffraction, N2 adsorption/desorption isotherms, UV-Raman spectroscopy, and scanning electron microscopy. The surface acidity and the redox properties were characterized by ammonia temperature-programmed desorption and H2 temperature-programmed reduction, respectively. The results show that the addition of a proper amount of(Ce,Cr)xO2 over Nb2O5 significantly improves the intrinsic catalytic activity towards the deep oxidation of DCE, and only a very small amount of C2H3Cl is detected as the byproduct of the oxidation process. Further study reveals the existence of an obvious synergistic effect between Nb2O5, with abundant strong acid sites, and(Ce,Cr)xO2, with strong oxidation sites, as the strong acid sites of Nb2O5 promote the adsorption and dehydrochlorination of DCE, while the strong oxidation sites of(Ce,Cr)xO2 contribute to the deep oxidation of the reactant, intermediates, and byproducts. 展开更多
关键词 1 2-DICHLOROETHANE Deep oxidation Mixed oxide NB2O5 Synergistic effect
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Fabrication and Electrical Properties of Titanium Oxide by Thermally Oxidizing Titanium on Silicon
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作者 朱晖文 赵柏儒 +2 位作者 刘晓彦 康晋锋 韩汝琦 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第4期337-341,共5页
Polycrystalline titanium oxide films are fabricated on silicon by thermally oxidizing titanium.The current- voltage and capacitance- voltage characteristics of the Ag/Ti Ox/Si/Ag capacitors are m easured.The thicknes... Polycrystalline titanium oxide films are fabricated on silicon by thermally oxidizing titanium.The current- voltage and capacitance- voltage characteristics of the Ag/Ti Ox/Si/Ag capacitors are m easured.The thickness of the titanium oxide films arranges from15 0 nm to2 5 0 nm,and their dielectric constants are within40~ 87.As the oxida- tion tim e is shortened,the fixed charges of the titanium oxide films become less and the leakage current characteris- tics becom e better. 展开更多
关键词 high k m aterials therm ally oxidation DC m agnetron sputtering
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Isolation and characterization of ferrous-and sulfur-oxidizing bacteria from Tengchong solfataric region,China 被引量:5
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作者 JIANG Chengying LIU Ying +2 位作者 LIU Yanyang GUO Xu LIU Shuang-Jiang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2009年第9期1247-1252,共6页
Microbial oxidation and reduction of iron and sulfur are important parts of biogeochemical cycles in acidic environments such as geothermal solfataric regions. Species of Acidithiobacillus and Leptospirillum are the c... Microbial oxidation and reduction of iron and sulfur are important parts of biogeochemical cycles in acidic environments such as geothermal solfataric regions. Species of Acidithiobacillus and Leptospirillum are the common ferrous-iron and sulfur oxidizers from such environments. This study focused on the Tengchong sofataric region, located in Yunnan Province, Southwest China. Based on cultivation, 9 strains that grow on ferrous-iron and sulfuric compounds were obtained. Analysis of 16S rRNA genes of the 9 strains indicated that they were affiliated to AcidithiobaciUus, Alicyclobacillus, Sulfobacillus, Leptospirillum and Acidiphilium. Physiological and phylogenetic studies indicated that two strains (TC-34 and TC-71) might represent two novel members of Alicyclobacillus. Strain TC-34 and TC-71 showed 94.8%-97.1% 16S rRNA gene identities to other species of Alicyclobacillus. Different from the previously described Alicyclobacillus species, strains TC-34 and TC-71 were mesophilic and their cellular fatty acids do not contain w-cyclic fatty acids. Strain TC-71 was obligately dependent on ferrous-iron for growth. It was concluded that the ferrous-iron oxidizers were diversified and Alicyclobacillus species were proposed to take part in biochemical geocycling of iron in the Tengchong solfataric region. 展开更多
关键词 ferrous-iron oxidation sulfur oxidation biogeochemical cycle Alicyclobacillus solfataric region
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Deep Desulfurization of Diesel Fuels with Plasma/Air as Oxidizing Medium,Diperiodatocuprate(Ⅲ)as Catalyzer and Ionic Liquid as Extraction Solvent 被引量:3
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作者 班丽丽 刘平 +1 位作者 马存花 代斌 《Plasma Science and Technology》 SCIE EI CAS CSCD 2013年第12期1226-1231,共6页
In this paper, the oxidative desulfurization (ODS) system is directly applied to deal with the catalytic oxidation of sulfur compounds of sulfur-containing model oil by dielectric barrier discharge (DBD) plasma in... In this paper, the oxidative desulfurization (ODS) system is directly applied to deal with the catalytic oxidation of sulfur compounds of sulfur-containing model oil by dielectric barrier discharge (DBD) plasma in the presence of air plus an extraction step with the oxidation-treated fuel put over ionic liquid [BMIM]FeC14 (1-butyl-3-methylimidazolium tetrachloroferrate). This new system exhibited an excellent desulfurization effect. The sulfur content of DBT in diesel oil decreased from 200 ppm to 4.92 ppm (S removal rate up to 97.5%) under the following optimal reaction conditions: air flow rate (v) of 60 mL/min, amplitude of applied voltage (U) on DBD of 16 kV, input frequency (f) of 79 kHz, catalyst amount (w) of 1.25 wt%, reaction time (t) of 10 min. Moreover, a high desulfurization rate was obtained during oxidation of benzothiophene (BT) or 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) under the aforementioned conditions. The oxidation reactivity of different S compounds was decreased in the order of DBT, 4,6-DMDBT and BT. The remarkable advantage of the novel ODS system is that the desulfurization condition applies in the presence of air at ambient conditions without peroxides, aqueous solvent or biphasic oil-aqueous solution system. 展开更多
关键词 dielectric barrier discharge catalytic oxidative desulfurization ionic liquid diperiodatocuprate (III)
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High Temperature Corrosion of Fe-C-S Cast Irons in Oxidizing and Sulfidizing Atmospheres 被引量:1
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作者 Thuan-Dinh NGUYEN Dong-Bok LEE 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2008年第3期327-329,共3页
The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was fas... The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Fe0.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron. 展开更多
关键词 Cast iron OXIDATION SULFIDATION
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Diversification of ammonia-oxidizing microorganisms in seven geographically different paddy soils in Sichuan 被引量:1
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作者 LU Lu LI Hui-lin +3 位作者 HE Yan YANG Hong ZHANG Jing PENG Chao 《Journal of Chongqing University》 CAS 2018年第4期119-134,共16页
The diversification of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities and their potential nitrification activity (PNA) on a large scale have not been well documented. In this work, se... The diversification of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities and their potential nitrification activity (PNA) on a large scale have not been well documented. In this work, seven paddy soils from different geographic regions in Sichuan, P. R. China were selected to determine the spatial distribution of the activities, abundances and community compositions of AOB and AOA. PNA varied greatly among paddy soils, and was positively correlated with soil pH (P< 0.05). The abundance of AOA was 81.1 to 1 670.0 times more than that of AOB, which indicates paddy soil environments favor the growth of AOA. Denaturing gradient gel electrophoresis fingerprints of amoA genes exhibited distinct spatial differences in AOA compositions rather than in AOB compositions. Sequencing analysis revealed that acidic soils were dominated by AOA within marine group 1.1 a-associated lineage, whereas the soil group 1.1b lineage AOA predominated in neutral and alkaline soils. Both nitrosopira cluster 3-like and Nitrosomonas cluster 7-like AOB dominated the AOB communities in the paddy soils. Redundancy analysis suggested that soil NH4^+-N content was the most significant driver determining the AOB community structure, while no significant correlation between AOA community structure and soil properties was found. The findings highlight that the activity and composition of ammonia oxidizers exhibit spatial variations in complex paddy fields due to the joint influence of soil variables associated with pH and N availability. 展开更多
关键词 PADDY soil AMMONIA oxidizers large geographical scale potential NITRIFICATION activity DIVERSIFICATION
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Quantification of anaerobic ammonium-oxidizing bacteria in enrichment cultures by quantitative competitive PCR 被引量:1
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作者 HAO Chun WANG Huan +1 位作者 LIU Qinhua LI Xudong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2009年第11期1557-1561,共5页
The anaerobic ammonium-oxidizing (ANAMMOX) bacteria were enriched from a sequencing batch biofilm reactor (SBBR). A quantitative competitive polymerase chain reaction (QC-PCR) system was successfully developed t... The anaerobic ammonium-oxidizing (ANAMMOX) bacteria were enriched from a sequencing batch biofilm reactor (SBBR). A quantitative competitive polymerase chain reaction (QC-PCR) system was successfully developed to detect and quantify ANAMMOX bacteria in environmental samples. For QC-PCR system, PCR primer sets targeting 16S ribosomal RNA genes of ANAMMOX bacteria were designed and used. The quantification range of this system was 4 orders of magnitude, from 10^3 to 10^6 copies per PCR, corresponding to the detection limit of 300 target copies per mL. A 312-bp internal standard was constructed, which showed very similar amplification efficiency with the target amxC fragment (349 bp) over 4 orders of magnitude (10^3-10^6). The linear regressions were obtained with R^2 of 0.9824 for 10^3 copies, 0.9882 for 10^4 copies, 0.9857 for 10^5 copies and 0.9899 for 10^6 copies, respectively. Using this method, ANAMMOX bacteria were quantified in a shortcut nitrification/denitrification-anammox system which was set for piggery wastewater treatment. 展开更多
关键词 anaerobic ammonium oxidation 16S rRNA approach quantitative competitive PCR
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Oxidizing Cellulose to 2,3-Dialdehyde Cellulose by Sodium Periodate 被引量:1
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作者 孟舒献 冯亚青 +2 位作者 梁足培 付强 张恩仲 《Transactions of Tianjin University》 EI CAS 2005年第4期250-254,共5页
Study on oxidizing cellulose to 2.3-dialdehyde cellulose by sodium periodate (NalO4) was carried out. The effects of reaction conditions such as pH of solution, temperature, oxidant concentration, oxidation time. th... Study on oxidizing cellulose to 2.3-dialdehyde cellulose by sodium periodate (NalO4) was carried out. The effects of reaction conditions such as pH of solution, temperature, oxidant concentration, oxidation time. the particle size of 2,3-dialdehyde cellulose and alkali treatment temperature on the dialdehyde concentration ot cellulose were investigated in detail, The results show that the aldehyde group content was created while reaction temperature and alkali treatment temperature increased. The most principal factors affecting the aldehyde group content of 2,3-dialdehyde cellulose were found out and the best oxidation conditions were as follows: the pH was 2. the reaction temperature was 45℃. the mass ratio of cellulose to NalO4 was 1/2, the reaction time was 4 h, the alkali treatment temperature was 70℃ and smaller particle size was 0.80 mm. 展开更多
关键词 CELLULOSE oxidation: 2.3-dialdehyde cellulose sodium periodate
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Joining Al_2O_3-ZrO_2 Ceramics by Direct Oxidizing Metal Method
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作者 叶浩 刘家臣 张君娣 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第S1期182-184,共3页
Effects of interlayer composition on bonding strength and interfacial microstructure of green joined Al_2O_3-ZrO_2 ceramics were studied in this paper. Green bodies of Al_2O_3 and ZrO_2 ceramics were joined by using i... Effects of interlayer composition on bonding strength and interfacial microstructure of green joined Al_2O_3-ZrO_2 ceramics were studied in this paper. Green bodies of Al_2O_3 and ZrO_2 ceramics were joined by using interlayer composed of Al_2O_3-Al-SiO_2 system at 1550 ℃ for 2 h without applied pressure. The effect of Al on the bond strength and microstructure of the joints were investigated. Through comparing five approaches or conditions, the results indicate that when adding 22% Al, the joints are the best in terms of bend strength and the microstructures of the joints are homogeneous and without obvious cracks, pores and defects. 展开更多
关键词 joining OXIDATION ALUMINA ZIRCONIA
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