The Boulon Djounga eastern perimeter is part of the Tiawa operating permit of the Société des Mines du Liptako (SML), located in the central southwestern part of Liptako (Niger). In this study, we used field...The Boulon Djounga eastern perimeter is part of the Tiawa operating permit of the Société des Mines du Liptako (SML), located in the central southwestern part of Liptako (Niger). In this study, we used field data, Reverse Circulation (RC) surveys and chemical analyzes of gold to determine the characteristics of gold and its mineralization style. The eastern perimeter of Boulon Djounga is represented by a succession of metabasalts and metasediments both intersected by intrusions of quartz and dolerite dykes, and covered by sandstone and clayey rocks. Gold is present in low contents (0.00 - 0.30 ppm) in the sedimentary cover and in medium (0.30 - 1.00 ppm) or high contents (1.00 - 4.534 ppm) in the metasediments, and in the gray quartz veins and locally in the volcanics. It exists in a disseminated state or in a concentrated state in the surrounding areas in the form of discrete grains associated with sulphurous minerals (pyrite: FeS<sub>2</sub>, chalcopyrite: CuFeS<sub>2</sub> or arsenopyrite: FeAsS). The presence of gold in the quartz veins, and the NE-SW and NW-SE orientations of the ore bodies suggest that the eastern Boulon Djounga gold mineralization would be established during a late magmatic extensive phase.展开更多
This article deals with the influence of the partial substitution of bitumen by a mixture of sulphur and tyre and plastic bottle powders on the characterization of asphalt concrete. The approach adopted was to subject...This article deals with the influence of the partial substitution of bitumen by a mixture of sulphur and tyre and plastic bottle powders on the characterization of asphalt concrete. The approach adopted was to subject a control asphalt concrete to level 2 formulation tests as well as those modified at 10%, 20%, 30% and 40% by substituting bitumen with a mixture of tyre powder, plastic bottle powder and sulphur at 40%, 28% and 32% respectively. The results of the PCG, Duriez and rutting tests carried out on the control and modified bituminous concretes (manufactured using the wet process) revealed three (03) major findings, in particular with regard to workability, resistance to simple compression and rutting. The experimental results show an increasing trend in the essential parameters. At 40% substitution, there was a 22.73% increase in compactness, reflecting a significant improvement in the material’s workability. With regard to simple compressive strength, the increase is 34.02% at 40% substitution, highlighting the limitation of crack formation and propagation under heavy precipitation. With regard to rutting, the 16% drop in susceptibility at 40% substitution reflects a significant improvement in the behaviour of the material under dynamic mechanical stresses in heavy precipitation. The improvement in these behaviours results from the insertion of the plastic bottle powder into the interstices of the granular skeleton, thus reducing its cellular structure, and also from the interactions between the sulphur with the tyre powder and the sulphur with the plastic bottle powder, i.e. cross-linking or vulcanisation.展开更多
The process of lignite desulphurization via its treatment by an oxidant(air or air–steam mixture)has been studied.The research objective was useful determination of steam application in oxidative lignite desulphuriza...The process of lignite desulphurization via its treatment by an oxidant(air or air–steam mixture)has been studied.The research objective was useful determination of steam application in oxidative lignite desulphurization.It has been proved that the water steam should be included in the oxidant composition to increase the hydrogen sulphide and combustible constituent content in the gases obtained during the processes under research.The impact of factors which affect the reactions between solid(in our case–lignite)and gaseous reagent(oxidant,i.e.air and or air–steam mixture)upon the research process has been investigated,if these reactions occur in the kinetic area.Such factors are linear rate of oxidant movement and coal grain size.The values of oxidant movement linear rate and coal grain size,which the reaction transfer from pyrite sulphur and organic content of lignite from diffusion into kinetic area occurs by,have been determined.Under these‘‘transfer’’conditions,the values of coefficients of oxidant mass transfer(β,m/s)as well as Sherwood criteria and boiling layer differences have been calculated.展开更多
Water shortage has threatened sustainable development of agriculture globally as well as in the North China Plain(NCP).Irrigation,as the most effective way to increase food production in dry land,may not be readily ...Water shortage has threatened sustainable development of agriculture globally as well as in the North China Plain(NCP).Irrigation,as the most effective way to increase food production in dry land,may not be readily available in the situation of drought.One of the alternatives is to supply plants with enough nutrients so that they can be more sustainable to the water stress.The objective of this study was to explore effects of irrigation and sulphur(S)application on water consumption,dry matter accumulation(DMA),and grain yield of winter wheat in NCP.Three irrigation regimes including no irrigation(rainfed,I0)during the whole growth period,once irrigation only at jointing stage(90 mm,I1),and twice respective irrigation at jointing and anthesis stages(90 mm plus 90 mm,I2),and two levels of S application including 0S0and 60 kg ha^–1(S60)were designed in the field experiment in NCP.Results showed that increasing irrigation times significantly increased mean grain yield of wheat by 12.5–23.7%and nitrogen partial factor productivity(NPFP)by 21.2–45.0%in two wheat seasons,but markedly decreased crop water use efficiency(YWUE).Furthermore,S supply 60 kg ha^–1 significantly increased mean grain yield,YWUE,IWUE and NPFP by 5.6,6.1,23.2,and 5.6%(across two wheat seasons),respectively.However,we also found that role of soil moisture prior to S application was one of important greater factors on improving the absorption and utilization of storage water and nutrients of soil.Thus,water supply is still the most important factor to restrict the growth of wheat in the present case of NCP,supplying 60 kg ha^–1 S with once irrigation 90 mm at the jointing stage is a relatively appropriate recommended combination to improve grain yield and WUE of wheat when saving water resources is be considered in irrigated wheat farmlands of NCP.展开更多
Composite layer with nitrocarbonide and sulfide was made on the surface of CrMoCu alloy cast iron by combined treatment of ion nitrocarburizing and sulphurizing. The composite layer is composed of sulfide layer, nitro...Composite layer with nitrocarbonide and sulfide was made on the surface of CrMoCu alloy cast iron by combined treatment of ion nitrocarburizing and sulphurizing. The composite layer is composed of sulfide layer, nitrocarbonide hypo-surface layer and its diffusing layer, the size of sulfide globular grains distributing equably on the surface is in nano-micron-scale, and the phase structure of the composite layer is composed of FeS, FeS1-x, Fe2C and Fe3N. Under oil lubrication, sulphurized surface shows good scuffing-resistance only under low velocity, and nitrocarburized and sulphurized surface greatly improves the scuffing-resistance and wear-resistance of CrMoCu alloy cast iron, its integrated friction and wear properties are better than those of the plain and sulphurized surfaces under all the velocities.展开更多
In order to enhance the lead and zinc recovery from the refractory Pb-Zn oxide ore, a new technology was developed based on sulfidation roasting with sulphur by temperature gradient method. The solid-liquid reaction s...In order to enhance the lead and zinc recovery from the refractory Pb-Zn oxide ore, a new technology was developed based on sulfidation roasting with sulphur by temperature gradient method. The solid-liquid reaction system was established and the sulfidation thermodynamics of lead and zinc carbonate was calculated with the software HSC 5.0. The effects of roasting temperature,molar ratio of sulphur to lead and zinc carbonate and reaction time in the first step roasting, and holding temperature and time in the second roasting on the sulfidation extent were studied at a laboratory-scale. The experimental results show that the sulfidation extents of lead and zinc are 96.50% and 97.29% under the optimal conditions, respectively, and the artificial galena, sphalerite and wurtzite were formed. By the novel sulfidizing process, it is expected that the sulphides can be recovered by conventional flotation technology.展开更多
Leaching mechanism of acid roasted ore in the spodumene sulphuric acid process was investigated. Experimental results of leaching rates along with variations of leaching temperature in the acidized and neutral leachin...Leaching mechanism of acid roasted ore in the spodumene sulphuric acid process was investigated. Experimental results of leaching rates along with variations of leaching temperature in the acidized and neutral leaching processes were reported. Applying ion exchange mechanism in acidized roasting and absorption entrainment mechanism at high temperature, leaching mechanism was discussed. A better explanation of experimental results was given.展开更多
The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combin...The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combined with the rotating disc electrode (RDE).The Koutecky-Levich plot indicated that the dissolved O_2 reduction at the copper electrode was an apparent four-electron process.A correlation between the presence of dissolved O_2 and the formation of Cu_2O,confirmed from XRD,was discussed. Ascorbic a...展开更多
Remarkable progress has been made in conjugated copoly-mer donors due to the development of novel fused-ring ac-ceptor(FRA)building units[1−15].The copolymers based on FRA units have delivered excellent power conversi...Remarkable progress has been made in conjugated copoly-mer donors due to the development of novel fused-ring ac-ceptor(FRA)building units[1−15].The copolymers based on FRA units have delivered excellent power conversion efficien-cies(PCEs)up to 18.69%in organic solar cells(OSCs)[16].Fused-ring aromatic lactones are promising FRA units[17−19].展开更多
The oxidative desulphurization process of coal with different metamorphism degrees treated by an air-steam mixture has been studied.It has been shown that the pyrite present in black coal and anthracite is oxidized wi...The oxidative desulphurization process of coal with different metamorphism degrees treated by an air-steam mixture has been studied.It has been shown that the pyrite present in black coal and anthracite is oxidized with the sulphur dioxide formation,and the process chemical mechanism does not depend on the quality of organic matter.The medium-metamorphized coal,capable of turning into a plastic state and cake in the range of investigated temperatures(350~450 ℃),is desulphurized with the greatest difficulty.The chemical mechanism dealing with the transformations of pyritic sulphur present in brown coal differs from similar processes taking place in black coal and anthracite,because FeS2 is converted with hydrogen sulphide formation at desulphurization.展开更多
The experimental research on refining slag systems for ultra-low sulphur steel was carried out in a 10 kg induction furnace.It was proved that sulphur element in molten steel can be removed to less than 5×10^(-6)...The experimental research on refining slag systems for ultra-low sulphur steel was carried out in a 10 kg induction furnace.It was proved that sulphur element in molten steel can be removed to less than 5×10^(-6) by adding CaO-Al_2O_3-SiO_2-MgO-CaF_2 slag on the surface of molten steel and feeding CaO-BaO-CaF2 wire into molten steel.And L_s,which is the coefficient of sulphur between slag and molten steel,that is ω(s)/ω[s],increases by increasing I(I = ωBaO/ωCaO).When I=5/3,L_s can be up to its maximum of 633.The CaSi is effective for deep desulphurization,especially when it is added to the slag of wire feeding.展开更多
Concentration and source rate of precursor vapors participating in particle formation and subsequent growth were investigated during the Pearl River Delta intensive campaign (PRD2004, October 2004) in southeastern C...Concentration and source rate of precursor vapors participating in particle formation and subsequent growth were investigated during the Pearl River Delta intensive campaign (PRD2004, October 2004) in southeastern China. Four new particle formation event days and a typical non-event day were selected for our analysis. Atmospheric sulphuric acid, the important precursor vapor in nucleation and growth, were simulated with a pseudo steady-state model based on the measurements of SO2, NOx, 03, CO, non-methane hydrocarbon (NMHC) and ambient particle number concentrations as well as modeled photolysis frequencies obtained from measurements. The maximum midday sulphuric acid concentrations vary from 4.53 × 10^7 to 2.17 × 10^8 molecules cm^-3, the corresponding source rate via reaction of OH and SO2 range between 2.37 × 10^6 and 1.16 × 10^7 molecules cm^-3 s^-1. Nucleation mode growth rate was derived from size spectral evolution during the events to be 6.8-13.8 nm h^-1. Based on the growth rate, concentration of the vapors participating in subsequent growth were estimated to vary from 1.32 × 10^8 to 2.80 × 10^8 molecules cm^-3 with corresponding source rate between 7.26 × 10^6 and 1.64 × 10^7 molecules cm^-3 s^-1. Our results show the degree of pollution is larger in PRD. Sulphuric acid concentrations are fairly high and have a close correlation with new particle formation events. Budget analysis shows that sulphuric acid alone is not enough for required growth; other nonvolatile vapors are needed. However, sulphuric acid plays an important role in growth; the contribution of sulphuric acid to growth in PRD is 12.4%-65.2%.展开更多
Lithium-sulphur(Li-S)batteries are currently considered as next-generation battery technology.Sulphur is an attractive positive electrode for lithium metal batteries,mainly due to its high capacity(1675 m Ah g^(-1))an...Lithium-sulphur(Li-S)batteries are currently considered as next-generation battery technology.Sulphur is an attractive positive electrode for lithium metal batteries,mainly due to its high capacity(1675 m Ah g^(-1))and high specific energy(2600 Wh kg^(-1)).The electrochemical reaction of lithium with sulphur in non-aqueous electrolytes results in the formation of electrolyte soluble intermediate lithium-polysulphides.The dissolved polysulphides shuttle to the anode and get reduced at the anode resulting in Li metal corrosion.The solubility of polysulphide gradually reduces the amount of sulphur in the cathode,thereby limiting the cycle life of Li-S batteries.Several strategies have been proposed to improve the cycling stability of Li-S batteries.A unique approach to eliminate the polysulphide shuttle is to use ultramicroporous carbon(UMC)as a host for sulphur.The pore size of UMC which is below 7A,is the bottleneck for carbonate solvents to access sulphur/polysulphides confined in the pores,thereby preventing the polysulphide dissolution.This perspective article will emphasise the role of UMC host in directing the lithiation mechanism of sulphur and in inhibiting polysulphide dissolution,including the resulting parasitic reaction on the lithium anode.Further,the challenges that need to be addressed by UMC-S based Li-S batteries,and the strategies to realise high power density,high Coulombic efficiency,and resilient Li-S batteries will be discussed.展开更多
A novel polyquaternaryammonium cationic sulphur black dye was synthesized and its dyeing behavior on silk was studied. The dye exhibited excellent dyeing fixation of up to 98.2 %, as well as excellent dyeing fastnes...A novel polyquaternaryammonium cationic sulphur black dye was synthesized and its dyeing behavior on silk was studied. The dye exhibited excellent dyeing fixation of up to 98.2 %, as well as excellent dyeing fastness on silk.展开更多
Objective:To verify through a scientific mean the therapeutic use of the plant as an anti-tussive agent,by traditional medicine healers and also aid in the search for new drugs developments from plants.Methods:The roo...Objective:To verify through a scientific mean the therapeutic use of the plant as an anti-tussive agent,by traditional medicine healers and also aid in the search for new drugs developments from plants.Methods:The roots of Triclisia dictyophylla were investigated for their antitussive properties.The plant was uprooted in the month of June 2003 at Igbodo,Delta State,Nigeria and was taken to the university of Nigeria Nsukka for taxonomy. The roots were chopped,ground and immersed in pure drinking water for 24 hours.After filtration, extraction was carried out using a Rotary evaporator,preliminary phytochemistry and acute toxicity studies were carried out.Antitussive study was carried out using a total of 42 young rats of average weight of 72.2 g.The rats were housed in standard animal house of the university and were allowed access to feeds and water but, were fasted for 12 hours prior to commencement of experiment.Specific and appropriate dosage of the crude extract and Codeine re - dissolved in water were administered orally 30 minutes prior to induction of cough. Cough was induced by exposing the animals to Sulphure dioxide gas for 3- minutes.Coughing was taken as number of Head-nods per minute,Stethoscope aided audible sounds and,or tears secretion.Percentage cough inhibition for crude extract and,or Codeine treated rats were compared with reference to control animals.Results were subjected to statistical analysis using SPSS 13.0.Results:A 10.2%extraction yield was got from a starting root initial weight of 320 g.The preliminary phytochemistry of the aqueous root extract revealed the presence of alkaloids,saponins,flavonoids,proteins,reducing sugars,steroids,resins fats/oils and glycosides. The Median lethal dose(LD_(50)) based on Lorke's 1983 method was 548 mg/kg The aqueous root extract at concentrations of 10 mg/kg,50 mg/kg,100 mg/kg and 200 mg/kg orally administered,inhibited cough in rats induced by sulphure dioxide gas by 16.67%,33.33%,50.00%and 83.33%respectively.While Codeine phosphate,a standard antitussive agent,at oral concentrations of 10 mg/kg and 20 mg/kg inhibited cough in rats induced by sulphure dioxide gas by 33.33%and 60.67%respectively.Conclusion:Earlier works by some authors had led to isolation of Morhinian Alkaloids from Triclisia dictyophylla thus most probably linking its mechanism of antitussive activity to that likable of Morphine.This study justifies the use of the plant in treatment of cough by Traditional Medicine Healers.展开更多
文摘The Boulon Djounga eastern perimeter is part of the Tiawa operating permit of the Société des Mines du Liptako (SML), located in the central southwestern part of Liptako (Niger). In this study, we used field data, Reverse Circulation (RC) surveys and chemical analyzes of gold to determine the characteristics of gold and its mineralization style. The eastern perimeter of Boulon Djounga is represented by a succession of metabasalts and metasediments both intersected by intrusions of quartz and dolerite dykes, and covered by sandstone and clayey rocks. Gold is present in low contents (0.00 - 0.30 ppm) in the sedimentary cover and in medium (0.30 - 1.00 ppm) or high contents (1.00 - 4.534 ppm) in the metasediments, and in the gray quartz veins and locally in the volcanics. It exists in a disseminated state or in a concentrated state in the surrounding areas in the form of discrete grains associated with sulphurous minerals (pyrite: FeS<sub>2</sub>, chalcopyrite: CuFeS<sub>2</sub> or arsenopyrite: FeAsS). The presence of gold in the quartz veins, and the NE-SW and NW-SE orientations of the ore bodies suggest that the eastern Boulon Djounga gold mineralization would be established during a late magmatic extensive phase.
文摘This article deals with the influence of the partial substitution of bitumen by a mixture of sulphur and tyre and plastic bottle powders on the characterization of asphalt concrete. The approach adopted was to subject a control asphalt concrete to level 2 formulation tests as well as those modified at 10%, 20%, 30% and 40% by substituting bitumen with a mixture of tyre powder, plastic bottle powder and sulphur at 40%, 28% and 32% respectively. The results of the PCG, Duriez and rutting tests carried out on the control and modified bituminous concretes (manufactured using the wet process) revealed three (03) major findings, in particular with regard to workability, resistance to simple compression and rutting. The experimental results show an increasing trend in the essential parameters. At 40% substitution, there was a 22.73% increase in compactness, reflecting a significant improvement in the material’s workability. With regard to simple compressive strength, the increase is 34.02% at 40% substitution, highlighting the limitation of crack formation and propagation under heavy precipitation. With regard to rutting, the 16% drop in susceptibility at 40% substitution reflects a significant improvement in the behaviour of the material under dynamic mechanical stresses in heavy precipitation. The improvement in these behaviours results from the insertion of the plastic bottle powder into the interstices of the granular skeleton, thus reducing its cellular structure, and also from the interactions between the sulphur with the tyre powder and the sulphur with the plastic bottle powder, i.e. cross-linking or vulcanisation.
文摘The process of lignite desulphurization via its treatment by an oxidant(air or air–steam mixture)has been studied.The research objective was useful determination of steam application in oxidative lignite desulphurization.It has been proved that the water steam should be included in the oxidant composition to increase the hydrogen sulphide and combustible constituent content in the gases obtained during the processes under research.The impact of factors which affect the reactions between solid(in our case–lignite)and gaseous reagent(oxidant,i.e.air and or air–steam mixture)upon the research process has been investigated,if these reactions occur in the kinetic area.Such factors are linear rate of oxidant movement and coal grain size.The values of oxidant movement linear rate and coal grain size,which the reaction transfer from pyrite sulphur and organic content of lignite from diffusion into kinetic area occurs by,have been determined.Under these‘‘transfer’’conditions,the values of coefficients of oxidant mass transfer(β,m/s)as well as Sherwood criteria and boiling layer differences have been calculated.
基金supported by the National Natural Science Foundation of China (31272246)the National Key Technologies R&D Program of China during the 12th Five-Year Plan period (2013BAD07B00, 2011BAD16B07 and 2015BAD26B01)the Special Fund for Agroscientific Research in the Public Interest, China (201203096, 201203079 and 201203031)
文摘Water shortage has threatened sustainable development of agriculture globally as well as in the North China Plain(NCP).Irrigation,as the most effective way to increase food production in dry land,may not be readily available in the situation of drought.One of the alternatives is to supply plants with enough nutrients so that they can be more sustainable to the water stress.The objective of this study was to explore effects of irrigation and sulphur(S)application on water consumption,dry matter accumulation(DMA),and grain yield of winter wheat in NCP.Three irrigation regimes including no irrigation(rainfed,I0)during the whole growth period,once irrigation only at jointing stage(90 mm,I1),and twice respective irrigation at jointing and anthesis stages(90 mm plus 90 mm,I2),and two levels of S application including 0S0and 60 kg ha^–1(S60)were designed in the field experiment in NCP.Results showed that increasing irrigation times significantly increased mean grain yield of wheat by 12.5–23.7%and nitrogen partial factor productivity(NPFP)by 21.2–45.0%in two wheat seasons,but markedly decreased crop water use efficiency(YWUE).Furthermore,S supply 60 kg ha^–1 significantly increased mean grain yield,YWUE,IWUE and NPFP by 5.6,6.1,23.2,and 5.6%(across two wheat seasons),respectively.However,we also found that role of soil moisture prior to S application was one of important greater factors on improving the absorption and utilization of storage water and nutrients of soil.Thus,water supply is still the most important factor to restrict the growth of wheat in the present case of NCP,supplying 60 kg ha^–1 S with once irrigation 90 mm at the jointing stage is a relatively appropriate recommended combination to improve grain yield and WUE of wheat when saving water resources is be considered in irrigated wheat farmlands of NCP.
基金Project (50235030) supported by the National Natural Science Foundation of China project (G1999065009) supported by the National Basic Research Program of China
文摘Composite layer with nitrocarbonide and sulfide was made on the surface of CrMoCu alloy cast iron by combined treatment of ion nitrocarburizing and sulphurizing. The composite layer is composed of sulfide layer, nitrocarbonide hypo-surface layer and its diffusing layer, the size of sulfide globular grains distributing equably on the surface is in nano-micron-scale, and the phase structure of the composite layer is composed of FeS, FeS1-x, Fe2C and Fe3N. Under oil lubrication, sulphurized surface shows good scuffing-resistance only under low velocity, and nitrocarburized and sulphurized surface greatly improves the scuffing-resistance and wear-resistance of CrMoCu alloy cast iron, its integrated friction and wear properties are better than those of the plain and sulphurized surfaces under all the velocities.
基金Project(51204210)supported by the National Natural Science Foundation of ChinaProject(2011AA061001)supported by the High-Tech Research and Development Program of ChinaProject(2012BAC12B04)supported by the National Science&Technology During the12th Five-Year Plan Period,China
文摘In order to enhance the lead and zinc recovery from the refractory Pb-Zn oxide ore, a new technology was developed based on sulfidation roasting with sulphur by temperature gradient method. The solid-liquid reaction system was established and the sulfidation thermodynamics of lead and zinc carbonate was calculated with the software HSC 5.0. The effects of roasting temperature,molar ratio of sulphur to lead and zinc carbonate and reaction time in the first step roasting, and holding temperature and time in the second roasting on the sulfidation extent were studied at a laboratory-scale. The experimental results show that the sulfidation extents of lead and zinc are 96.50% and 97.29% under the optimal conditions, respectively, and the artificial galena, sphalerite and wurtzite were formed. By the novel sulfidizing process, it is expected that the sulphides can be recovered by conventional flotation technology.
文摘Leaching mechanism of acid roasted ore in the spodumene sulphuric acid process was investigated. Experimental results of leaching rates along with variations of leaching temperature in the acidized and neutral leaching processes were reported. Applying ion exchange mechanism in acidized roasting and absorption entrainment mechanism at high temperature, leaching mechanism was discussed. A better explanation of experimental results was given.
文摘The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combined with the rotating disc electrode (RDE).The Koutecky-Levich plot indicated that the dissolved O_2 reduction at the copper electrode was an apparent four-electron process.A correlation between the presence of dissolved O_2 and the formation of Cu_2O,confirmed from XRD,was discussed. Ascorbic a...
文摘Remarkable progress has been made in conjugated copoly-mer donors due to the development of novel fused-ring ac-ceptor(FRA)building units[1−15].The copolymers based on FRA units have delivered excellent power conversion efficien-cies(PCEs)up to 18.69%in organic solar cells(OSCs)[16].Fused-ring aromatic lactones are promising FRA units[17−19].
文摘The oxidative desulphurization process of coal with different metamorphism degrees treated by an air-steam mixture has been studied.It has been shown that the pyrite present in black coal and anthracite is oxidized with the sulphur dioxide formation,and the process chemical mechanism does not depend on the quality of organic matter.The medium-metamorphized coal,capable of turning into a plastic state and cake in the range of investigated temperatures(350~450 ℃),is desulphurized with the greatest difficulty.The chemical mechanism dealing with the transformations of pyritic sulphur present in brown coal differs from similar processes taking place in black coal and anthracite,because FeS2 is converted with hydrogen sulphide formation at desulphurization.
基金Item Sponsored by National Key Fundamental Research Development Project of China(G1998061500)
文摘The experimental research on refining slag systems for ultra-low sulphur steel was carried out in a 10 kg induction furnace.It was proved that sulphur element in molten steel can be removed to less than 5×10^(-6) by adding CaO-Al_2O_3-SiO_2-MgO-CaF_2 slag on the surface of molten steel and feeding CaO-BaO-CaF2 wire into molten steel.And L_s,which is the coefficient of sulphur between slag and molten steel,that is ω(s)/ω[s],increases by increasing I(I = ωBaO/ωCaO).When I=5/3,L_s can be up to its maximum of 633.The CaSi is effective for deep desulphurization,especially when it is added to the slag of wire feeding.
基金China National Basic Research and Development Program (Grant Nos. 2002CB410801, 2002CB211605) National Natural Science Foundation of China (Grant No. 40405025).
文摘Concentration and source rate of precursor vapors participating in particle formation and subsequent growth were investigated during the Pearl River Delta intensive campaign (PRD2004, October 2004) in southeastern China. Four new particle formation event days and a typical non-event day were selected for our analysis. Atmospheric sulphuric acid, the important precursor vapor in nucleation and growth, were simulated with a pseudo steady-state model based on the measurements of SO2, NOx, 03, CO, non-methane hydrocarbon (NMHC) and ambient particle number concentrations as well as modeled photolysis frequencies obtained from measurements. The maximum midday sulphuric acid concentrations vary from 4.53 × 10^7 to 2.17 × 10^8 molecules cm^-3, the corresponding source rate via reaction of OH and SO2 range between 2.37 × 10^6 and 1.16 × 10^7 molecules cm^-3 s^-1. Nucleation mode growth rate was derived from size spectral evolution during the events to be 6.8-13.8 nm h^-1. Based on the growth rate, concentration of the vapors participating in subsequent growth were estimated to vary from 1.32 × 10^8 to 2.80 × 10^8 molecules cm^-3 with corresponding source rate between 7.26 × 10^6 and 1.64 × 10^7 molecules cm^-3 s^-1. Our results show the degree of pollution is larger in PRD. Sulphuric acid concentrations are fairly high and have a close correlation with new particle formation events. Budget analysis shows that sulphuric acid alone is not enough for required growth; other nonvolatile vapors are needed. However, sulphuric acid plays an important role in growth; the contribution of sulphuric acid to growth in PRD is 12.4%-65.2%.
基金partly funded by the German Research Foundation(DFG)under Project ID 390874152(POLiS Cluster of Excellence,EXC2154)。
文摘Lithium-sulphur(Li-S)batteries are currently considered as next-generation battery technology.Sulphur is an attractive positive electrode for lithium metal batteries,mainly due to its high capacity(1675 m Ah g^(-1))and high specific energy(2600 Wh kg^(-1)).The electrochemical reaction of lithium with sulphur in non-aqueous electrolytes results in the formation of electrolyte soluble intermediate lithium-polysulphides.The dissolved polysulphides shuttle to the anode and get reduced at the anode resulting in Li metal corrosion.The solubility of polysulphide gradually reduces the amount of sulphur in the cathode,thereby limiting the cycle life of Li-S batteries.Several strategies have been proposed to improve the cycling stability of Li-S batteries.A unique approach to eliminate the polysulphide shuttle is to use ultramicroporous carbon(UMC)as a host for sulphur.The pore size of UMC which is below 7A,is the bottleneck for carbonate solvents to access sulphur/polysulphides confined in the pores,thereby preventing the polysulphide dissolution.This perspective article will emphasise the role of UMC host in directing the lithiation mechanism of sulphur and in inhibiting polysulphide dissolution,including the resulting parasitic reaction on the lithium anode.Further,the challenges that need to be addressed by UMC-S based Li-S batteries,and the strategies to realise high power density,high Coulombic efficiency,and resilient Li-S batteries will be discussed.
基金support of the National Natural Science Foundation of China(NNSFC No.20276009)Trans-century Training Program Foundation for the Talents by the State Education Commission and Special Scientific Research Foundation of University Doctoral Program by the State Ministry of Education(No.20020141005).
文摘A novel polyquaternaryammonium cationic sulphur black dye was synthesized and its dyeing behavior on silk was studied. The dye exhibited excellent dyeing fixation of up to 98.2 %, as well as excellent dyeing fastness on silk.
文摘Objective:To verify through a scientific mean the therapeutic use of the plant as an anti-tussive agent,by traditional medicine healers and also aid in the search for new drugs developments from plants.Methods:The roots of Triclisia dictyophylla were investigated for their antitussive properties.The plant was uprooted in the month of June 2003 at Igbodo,Delta State,Nigeria and was taken to the university of Nigeria Nsukka for taxonomy. The roots were chopped,ground and immersed in pure drinking water for 24 hours.After filtration, extraction was carried out using a Rotary evaporator,preliminary phytochemistry and acute toxicity studies were carried out.Antitussive study was carried out using a total of 42 young rats of average weight of 72.2 g.The rats were housed in standard animal house of the university and were allowed access to feeds and water but, were fasted for 12 hours prior to commencement of experiment.Specific and appropriate dosage of the crude extract and Codeine re - dissolved in water were administered orally 30 minutes prior to induction of cough. Cough was induced by exposing the animals to Sulphure dioxide gas for 3- minutes.Coughing was taken as number of Head-nods per minute,Stethoscope aided audible sounds and,or tears secretion.Percentage cough inhibition for crude extract and,or Codeine treated rats were compared with reference to control animals.Results were subjected to statistical analysis using SPSS 13.0.Results:A 10.2%extraction yield was got from a starting root initial weight of 320 g.The preliminary phytochemistry of the aqueous root extract revealed the presence of alkaloids,saponins,flavonoids,proteins,reducing sugars,steroids,resins fats/oils and glycosides. The Median lethal dose(LD_(50)) based on Lorke's 1983 method was 548 mg/kg The aqueous root extract at concentrations of 10 mg/kg,50 mg/kg,100 mg/kg and 200 mg/kg orally administered,inhibited cough in rats induced by sulphure dioxide gas by 16.67%,33.33%,50.00%and 83.33%respectively.While Codeine phosphate,a standard antitussive agent,at oral concentrations of 10 mg/kg and 20 mg/kg inhibited cough in rats induced by sulphure dioxide gas by 33.33%and 60.67%respectively.Conclusion:Earlier works by some authors had led to isolation of Morhinian Alkaloids from Triclisia dictyophylla thus most probably linking its mechanism of antitussive activity to that likable of Morphine.This study justifies the use of the plant in treatment of cough by Traditional Medicine Healers.