A novel environmental friendly wheat seed coating agent was prepared from the natural polymer,biological pesticide,microfertilizer,microelements and other additives.The laboratory and field test results showed that it...A novel environmental friendly wheat seed coating agent was prepared from the natural polymer,biological pesticide,microfertilizer,microelements and other additives.The laboratory and field test results showed that it could enhance the yield up to 16% and reduce its input cost to 1/6 as compared with the conventional wheat seed coating agent.It is safe without causing any pollution and would have significant economic and environmental benefits.展开更多
With an extension of the geological entropy concept in porous media,the approach called directional entrogram is applied to link hydraulic behavior to the anisotropy of the 3D fracture networks.A metric called directi...With an extension of the geological entropy concept in porous media,the approach called directional entrogram is applied to link hydraulic behavior to the anisotropy of the 3D fracture networks.A metric called directional entropic scale is used to measure the anisotropy of spatial order in different directions.Compared with the traditional connectivity indexes based on the statistics of fracture geometry,the directional entropic scale is capable to quantify the anisotropy of connectivity and hydraulic conductivity in heterogeneous 3D fracture networks.According to the numerical analysis of directional entrogram and fluid flow in a number of the 3D fracture networks,the hydraulic conductivities and entropic scales in different directions both increase with spatial order(i.e.,trace length decreasing and spacing increasing)and are independent of the dip angle.As a result,the nonlinear correlation between the hydraulic conductivities and entropic scales from different directions can be unified as quadratic polynomial function,which can shed light on the anisotropic effect of spatial order and global entropy on the heterogeneous hydraulic behaviors.展开更多
This novel environmentally friendly wheat seed coating agent which has been made with natural polymer as the primary material could increase yield by about 9% compared with the conventionally virulent wheat seed coati...This novel environmentally friendly wheat seed coating agent which has been made with natural polymer as the primary material could increase yield by about 9% compared with the conventionally virulent wheat seed coating agent. In the premise of this production, the content of malondialdehyde (MDA) and peroxidase (POD) was determined. The results show that, after treated by the self-made wheat seed coating agent, the contents of the MDA were less than traditional group and the blank control group and POD contents were higher than traditional group and blank control group, this provides a good foundation on the further research of self-control wheat seed coating agent.展开更多
In underground mining by sublevel caving method, the deformation and damage of the surface induced by subsidence are the major challenging issues. The dynamic and soft backflling body increases the safety risks in the...In underground mining by sublevel caving method, the deformation and damage of the surface induced by subsidence are the major challenging issues. The dynamic and soft backflling body increases the safety risks in the subsiding area. In this paper, taking Zhangfushan iron mine as an example, the ore body and the general layout are focused on the safety of backflling of mined-out area. Then, we use the ANSYS software to construct a three-dimensional(3D) model for the mining area in the Zhangfushan iron mine. According to the simulation results of the initial mining stages, the ore body is stoped step by step as suggested in the design. The stability of the backflling is back analyzed based on the monitored displacements, considering the stress distribution to optimize the stoping sequence. The simulations show that a reasonable stoping sequence can minimize the concentration of high compressive stress and ensure the safety of stoping of the ore body.展开更多
The effect and mechanism of microwave irradiation on vanadium leaching were studied via a comparison between microwave heating and conventional heating. The results show a synergistic effect of microwave irradiation a...The effect and mechanism of microwave irradiation on vanadium leaching were studied via a comparison between microwave heating and conventional heating. The results show a synergistic effect of microwave irradiation and calcium fluoride(Ca F_2) on the vanadium leaching efficiency. It is confirmed that the vanadium leaching process can be improved by microwave irradiation when Ca F_2 is present. The leaching rate of vanadium under microwave irradiation is increased by 8%–15% when 5wt% Ca F_2 is added; by contrast,in the absence of Ca F_2,the leaching rate is almost unaffected compared to that by conventional heating. Morphological analysis reveals that the particles are gradually eroded by acid under microwave irradiation,whereas some of the fine particles in samples subjected to conventional heating are tightly covered by a flocculent silicate product. Moreover,a large amount of Al and V and a small amount of Si are dissolved from samples under microwave heating,as revealed by the elemental analysis of leachates. Fourier transform infrared spectroscopic analysis also indicates a higher mass transfer coefficient in the diffusion layer of the raw material by microwave irradiation. When Ca F_2 is present,the reaction energy barrier is lowered and the leaching process is controlled by the tightly covered product layer,resulting in a prominent effect of microwave irradiation.展开更多
A novel process for separation of red (Y2O3:Eu3+), blue(BaMgAl10O17:Eu2+) and green (CeMgAl10O17:Tb3) rare earth fluorescent powders was proposed. At first, the blue powder can be extracted selectively from an aqueous...A novel process for separation of red (Y2O3:Eu3+), blue(BaMgAl10O17:Eu2+) and green (CeMgAl10O17:Tb3) rare earth fluorescent powders was proposed. At first, the blue powder can be extracted selectively from an aqueous solution using a chelating collector 2-thenoyltrifluoroacetone (TTA) dissolved in heptane at alkaline pH condition, then, chloroform was used for extracting the green powder into organic phase. The red phosphor remains in aqueous phase with potassium sodium tartrate depressant (PST). Therefore, three phosphors can be separated successfully from their artificial mixtures by liquid/liquid extraction, and grades and recovery of separated products reach respectively as follows: red is 96.9% and 95.2%, blue is 82.7% and 98.8%, green is 94.6% and 82.6%.展开更多
A novel process for separation of red (Y2O3: Eu3+), blue (Sr, Ca, Ba)10(PO4)6Cl2: Eu2+ and green (LaPO4: Tb3+, Ce3+) fine tricolor phosphor powders was established. First, the green phosphor was extracted and separate...A novel process for separation of red (Y2O3: Eu3+), blue (Sr, Ca, Ba)10(PO4)6Cl2: Eu2+ and green (LaPO4: Tb3+, Ce3+) fine tricolor phosphor powders was established. First, the green phosphor was extracted and separated from three phosphor mixtures in heptane/DMF(N, N-Dimethylformamide) system using stearylamine or laurylamine (DDA) as the cationic surfactant. Then, after being treated with 99.5% ethanol, the blue and red phosphors could be separated in Heptane/DMF system in presence of 1-octanesulfonic acid sodium salt as the anionic surfactant. Satisfactory separation results have been achieved through two steps extractions with their artificial mixtures. The grades and recovery of separated products reached respectively as follows: red product was 95.3% and 90.9%, blue product was 90.0% and 95.2%, and green product was 92.2% and 91.8%.展开更多
Seedling period is an important stage of plant growth. This research was mainly to analysis the influence of chitosan on wheat seedling growth and physiological mechanisms under drought stress. The results showed that...Seedling period is an important stage of plant growth. This research was mainly to analysis the influence of chitosan on wheat seedling growth and physiological mechanisms under drought stress. The results showed that the group coated with chitosan significantly improved the growth index such as germination rate, wet weight, root length, root active, and impacted physiological indices such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)), the content of malwondialdehyde (MDA) and chlorophyll compared with CK under drought stress. Activities of POD, CAT and SOD increased and then decreased, the content of MDA increased under drought stress. But. variation rates of the group coated with chitosan were slower than that of CK, which indicates that chitosan can significantly improve anti-oxidant enzymes activity to clear timely active oxygen and reduce the content of MDA so as to alleviate the degree of damage in the drought stress and make seedlings grow better. The results also showed that chitosan improved chloro-phyll content than that of CK, which demonstrated that chlorophyll content significantly influenced the photosynthetic efficiency of the mutant and added wheat above ground biomass and the field experiment results showed that chitosan increased yield 13.6% than that of CK.展开更多
We used the no pollution natural polymer polysaccharide chitosan as the main raw material, which is supplemented by other additives, to prepare a high-efficiency environmental friendly maize seed coating agent. By det...We used the no pollution natural polymer polysaccharide chitosan as the main raw material, which is supplemented by other additives, to prepare a high-efficiency environmental friendly maize seed coating agent. By detecting the seed quality, maize seedling indexes, which include root activity, chlorophyll content and malondialdehyde (MDA) content, and through the results we found that this seed coating agent could improve the photosynthetic capacity and enhance seedling resistance. Laboratory bacteriostasis test and study showed that the antibacterial rate of this seed coating agent has reached more than 88%. Meanwhile, we analyzed and studied the antimicrobial mechanism of the seed coating agent.展开更多
By using acrylic acid copolymer, sodium citrate, hydrolyzed polymaleic anhydride (HPMA), corrosion inhibitor D and Zn2+ synergist as raw materials, a multi-component phosphate-free corrosion and scale inhibitor was de...By using acrylic acid copolymer, sodium citrate, hydrolyzed polymaleic anhydride (HPMA), corrosion inhibitor D and Zn2+ synergist as raw materials, a multi-component phosphate-free corrosion and scale inhibitor was developed. The performance of the composite phosphate-free corrosion and scale inhibitor was evaluated using the rotary hanging sheet corrosion test, the static scale inhibition test and the corrosion electrochemical test. And the surface morphology of the carbon steel was observed by scanning electronic microscope (SEM). Orthogonal experiment results indicated that the optimal mass ratios of amino acid: Zn2+ synergist: HPMA: corrosion inhibitor D: acrylic acid copolymer was 0.5:10:12:1:8. It was also observed that phosphate-free corrosion and scale inhibitor based on an anodic reaction through the electrochemical corrosion experiment, its annual corrosion rate and scale inhibition rate reached 0.0176 mm·a–1 and 98.3%, respectively, showing excellent corrosion and scale inhibition performance.展开更多
Geomechanical parameters are complex and uncertain.In order to take this complexity and uncertainty into account,a probabilistic back-analysis method combining the Bayesian probability with the least squares support v...Geomechanical parameters are complex and uncertain.In order to take this complexity and uncertainty into account,a probabilistic back-analysis method combining the Bayesian probability with the least squares support vector machine(LS-SVM) technique was proposed.The Bayesian probability was used to deal with the uncertainties in the geomechanical parameters,and an LS-SVM was utilized to establish the relationship between the displacement and the geomechanical parameters.The proposed approach was applied to the geomechanical parameter identification in a slope stability case study which was related to the permanent ship lock within the Three Gorges project in China.The results indicate that the proposed method presents the uncertainties in the geomechanical parameters reasonably well,and also improves the understanding that the monitored information is important in real projects.展开更多
Phosphorus(P)in surface runoff from purple soil is a critical element of agricultural nonpoint source pollution,leading to eutrophication of surface waters in the Three Gorges Reservoir Area(TGRA)of China.This work ai...Phosphorus(P)in surface runoff from purple soil is a critical element of agricultural nonpoint source pollution,leading to eutrophication of surface waters in the Three Gorges Reservoir Area(TGRA)of China.This work aimed to understand the processes and mechanisms of P losses from bare purple soil.Based on an indoor rainfall simulation experiment,we focused on the processes of surface runoff and P losses via different hydrological pathways.Experimental treatments included three simulated rainfall intensities,four slope gradients,and three fertilizer treatments.P loss from sediment was the main pathway in the purple soil,and bioavailable P was mainly transferred in dissolved P(DP)of runoff water.The P loss loads tend to grow with the increase of the slope until 25°for the maximum load of runoff water and 20°for the maximum load of sediment.Concentrations of DP in the surface runoff after fertilizer application can exceed the estimates of those required for accelerated eutrophication.Sediment P control might be an essential way for reducing P loss in purple soil for the local government and farmers of TGRA.展开更多
In the present study of peak particle velocity(PPV)and frequency,an improved algorithm(principal empirical mode decomposition,PEMD)based on principal component analysis(PCA)and empirical mode decomposition(EMD)is prop...In the present study of peak particle velocity(PPV)and frequency,an improved algorithm(principal empirical mode decomposition,PEMD)based on principal component analysis(PCA)and empirical mode decomposition(EMD)is proposed,with the goal of addressing poor filtering de-noising effects caused by the occurrences of modal aliasing phenomena in EMD blasting vibration signal decomposition processes.Test results showed that frequency of intrinsic mode function(IMF)components decomposed by PEMD gradually decreases and that the main frequency is unique,which eliminates the phenomenon of modal aliasing.In the simulation experiment,the signal-to-noise(SNR)and root mean square errors(RMSE)ratio of the signal de-noised by PEMD are the largest when compared to EMD and ensemble empirical mode decomposition(EEMD).The main frequency of the de-noising signal through PEMD is 75 Hz,which is closest to the frequency of the noiseless simulation signal.In geotechnical engineering blasting experiments,compared to EMD and EEMD,the signal de-noised by PEMD has the lowest level of distortion,and the frequency band is distributed in a range of 0-64 Hz,which is closest to the frequency band of the blasting vibration signal.In addition,the proportion of noise energy was the lowest,at 1.8%.展开更多
Water plays a critical role on the performance, stability and lifetime of proton exchange membrane fuel cells(PEMFCs). The addition of poly tetrafluoroethylene(PTFE) to the gas diffusion layer, especially, the cathode...Water plays a critical role on the performance, stability and lifetime of proton exchange membrane fuel cells(PEMFCs). The addition of poly tetrafluoroethylene(PTFE) to the gas diffusion layer, especially, the cathode side, would optimize the transportation of water, electron and gas and thus improve the performance of the fuel cell. But until now, the studies about directly applying the PTFE to the catalyst layer are rarely reported. In this paper, the membrane electrode is fabricated by using directly coating catalyst to the membrane method(CCM) and applying PTFE directly to the cathode electrode catalyst layer. The performance of the single cell is determined by polarization curves and durability tests. Electrochemical impedance spectroscopy(EIS) and scanning electron microscopy(SEM) techniques are used to characterize the electrochemical properties of PEMFC. Also the performance of a 10-cells stack is detected. Combining the performance and the physical-chemistry characterization of PEMFC shows that addition of appropriate content of PTFE to the electrode enhances the performance of the fuel cell, which may be due to the improved water management. Addition of appropriate content of PTFE enhances the interaction between the membrane and the catalyst layer, and bigger pores and highly textured structure form in the MEA, which favors the oxygen mass transfer and protons transfer in the fuel cell. While superfluous addition of PTFE covers the surface of catalysts and hindered the contact of catalyst with Nafion, which leads to the reduction of electrochemical active area and the decay of the fuel cell performance. The proposed research would optimize the water management of the fuel cell and thus improve the performance of the fuel cell.展开更多
Play behaviors and signals during playful interactions with juvenile conspecifics are important for both the social and cognitive development of young animals.The social organization of a species can also influence ju...Play behaviors and signals during playful interactions with juvenile conspecifics are important for both the social and cognitive development of young animals.The social organization of a species can also influence juvenile social play. We examined the relationships among play behaviors, candidate play signals, and play bout termination in Tibetan macaques(Macaca thibetana) during juvenile and infant social play to characterize the species play style. As Tibetan macaques are despotic and live in groups with strict linear dominance hierarchies and infrequent reconciliation, we predicted that play would be at risk of misinterpretation by both the individuals engaged in the play bout and by those watching, possibly leading to injury of the players. Animals living in such societies might need to frequently and clearly signal playful intent to play partners and other group members to avoid aggressive outcomes. We gathered video data on 21 individually-identified juvenile and infant macaques(one month to five years of age)from the Valley of the Wild Monkeys, Mt. Huangshan,China. We used all-occurrence sampling to record play behaviors and candidate play signals based on an ethogram. We predicted that play groups would use multiple candidate play signals in a variety of contexts and in association with the number of audience members in proximity to the players and play bout length. In the 283 playful interactions we scored,juvenile and infant macaques used multiple body and facial candidate play signals. Our data showed that juvenile and infant Tibetan macaques use a versatile repertoire of play behaviors and signals to sustain play.展开更多
The mechanical behaviors and energy dissipation characteristics of heat-treated granite were investigated under repeated impact loading.The granite samples were firstly heat-treated at the temperature of 20℃,200℃,40...The mechanical behaviors and energy dissipation characteristics of heat-treated granite were investigated under repeated impact loading.The granite samples were firstly heat-treated at the temperature of 20℃,200℃,400℃,and 600℃,respectively.The thermal damage characteristics of these samples were then observed and measured before impact tests.Dynamic impact compression tests finally were carried out using a modified split-Hopkinson pressure bar under three impact velocities of 12 m/s,15 m/s,and 18 m/s.These test results show that the mineral composition and the main oxides of the granite do not change with these treatment temperatures.The number of microcracks and microvoids decreases in the sample after 200℃ treatment.The mechanical properties of a sample after 600℃ treatment were rapidly deteriorated under the same impact velocity.The average of peak stress is much smaller than those after 20℃,200℃ and 400℃ treatments.The heat-treated samples have an energy threshold each.When the dissipated energy of a sample under a single impact is less than this threshold,the repeated impacts hardly lead to further damage accumulation even if its total breakage energy dissipation(BED)density is large.Under the same number of repeated impacts,the cumulative BED density of a sample after 600℃ treatment is the largest and its damage evolves most quickly.The total BED density of the sample after 200℃ treatment is the highest,which implies that this sample has better resistance to repeated impact,thus having less crack initiation and growth.展开更多
In the study, a novel environmental soybean seed coating agent was made of natural polymer, trace elements, trace fertilizer and biopesticides etc., with the condition of high performance-to-price ratio and environmen...In the study, a novel environmental soybean seed coating agent was made of natural polymer, trace elements, trace fertilizer and biopesticides etc., with the condition of high performance-to-price ratio and environmental friendliness. Effects of this soybean seed coating agent on soybean yield were tested through the laboratory and farm experiments. The tested results showed that the soybean yield using this seed coating agent was increased by 15.46%, and its cost was decreased by 27.8%, compared with the conventional soybean seed coating agent. It’s nontoxic and harmless to human and animals, more friendly to the environment. So it has obvious economic and environmental benefits.展开更多
Microwave heating can rapidly and uniformly raise the temperature and accelerate the reaction rate.In this paper,microwave heating was used to improve the acid leaching,and the mechanism was investigated via microscop...Microwave heating can rapidly and uniformly raise the temperature and accelerate the reaction rate.In this paper,microwave heating was used to improve the acid leaching,and the mechanism was investigated via microscopic morphology analysis and numerical simulation by COMSOL Multiphysics software.The effects of the microwave power,leaching temperature,CaF_(2) dosage,H_(2)SO_(4) concentration,and leaching time on the vanadium recovery were investigated.A vanadium recovery of 80.66%is obtained at a microwave power of 550 W,leaching temperature of 95℃,CaF_(2) dosage of 5wt%,H_(2)SO_(4) concentration of 20vol%,and leaching time of 2.5 h.Compared with conventional leaching technology,the vanadium recovery increases by 6.18%,and the leaching time shortens by 79.17%.More obvious pulverization of shale particles and delamination of mica minerals happen in the microwave-assisted leaching process.Numerical simulation results show that the temperature of vanadium shales increases with an increase in electric field(E-field).The distributions of E-field and temperature among vanadium shale particles are relatively uniform,except for the higher content at the contact position of the particles.The analysis results of scaleup experiments and leaching experiments indicate high-temperature hot spots in the process of microwave-assisted leaching,and the local high temperature destroys the mineral structure and accelerates the reaction rate.展开更多
基金supported by the Scientific and Tech-nological Project of Zhejiang Province,China (ZK-20061103)
文摘A novel environmental friendly wheat seed coating agent was prepared from the natural polymer,biological pesticide,microfertilizer,microelements and other additives.The laboratory and field test results showed that it could enhance the yield up to 16% and reduce its input cost to 1/6 as compared with the conventional wheat seed coating agent.It is safe without causing any pollution and would have significant economic and environmental benefits.
基金Foundation item： Projects（41172273, 40802079, 51108288） supported by the National Natural Science Foundation of China Project（KLE-TJGE-B1106） supported by the Opening Fund of Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education （Tongji University）, China
基金supported by the National Natural Science Foundation of China(Nos.42077243,52209148,and 52079062).
文摘With an extension of the geological entropy concept in porous media,the approach called directional entrogram is applied to link hydraulic behavior to the anisotropy of the 3D fracture networks.A metric called directional entropic scale is used to measure the anisotropy of spatial order in different directions.Compared with the traditional connectivity indexes based on the statistics of fracture geometry,the directional entropic scale is capable to quantify the anisotropy of connectivity and hydraulic conductivity in heterogeneous 3D fracture networks.According to the numerical analysis of directional entrogram and fluid flow in a number of the 3D fracture networks,the hydraulic conductivities and entropic scales in different directions both increase with spatial order(i.e.,trace length decreasing and spacing increasing)and are independent of the dip angle.As a result,the nonlinear correlation between the hydraulic conductivities and entropic scales from different directions can be unified as quadratic polynomial function,which can shed light on the anisotropic effect of spatial order and global entropy on the heterogeneous hydraulic behaviors.
文摘This novel environmentally friendly wheat seed coating agent which has been made with natural polymer as the primary material could increase yield by about 9% compared with the conventionally virulent wheat seed coating agent. In the premise of this production, the content of malondialdehyde (MDA) and peroxidase (POD) was determined. The results show that, after treated by the self-made wheat seed coating agent, the contents of the MDA were less than traditional group and the blank control group and POD contents were higher than traditional group and blank control group, this provides a good foundation on the further research of self-control wheat seed coating agent.
文摘In underground mining by sublevel caving method, the deformation and damage of the surface induced by subsidence are the major challenging issues. The dynamic and soft backflling body increases the safety risks in the subsiding area. In this paper, taking Zhangfushan iron mine as an example, the ore body and the general layout are focused on the safety of backflling of mined-out area. Then, we use the ANSYS software to construct a three-dimensional(3D) model for the mining area in the Zhangfushan iron mine. According to the simulation results of the initial mining stages, the ore body is stoped step by step as suggested in the design. The stability of the backflling is back analyzed based on the monitored displacements, considering the stress distribution to optimize the stoping sequence. The simulations show that a reasonable stoping sequence can minimize the concentration of high compressive stress and ensure the safety of stoping of the ore body.
基金financially supported by the National Natural Science Foundation of China(Nos.51474162 and 51404174)the Research Project of the Ministry of Education of China(No.213025A)
文摘The effect and mechanism of microwave irradiation on vanadium leaching were studied via a comparison between microwave heating and conventional heating. The results show a synergistic effect of microwave irradiation and calcium fluoride(Ca F_2) on the vanadium leaching efficiency. It is confirmed that the vanadium leaching process can be improved by microwave irradiation when Ca F_2 is present. The leaching rate of vanadium under microwave irradiation is increased by 8%–15% when 5wt% Ca F_2 is added; by contrast,in the absence of Ca F_2,the leaching rate is almost unaffected compared to that by conventional heating. Morphological analysis reveals that the particles are gradually eroded by acid under microwave irradiation,whereas some of the fine particles in samples subjected to conventional heating are tightly covered by a flocculent silicate product. Moreover,a large amount of Al and V and a small amount of Si are dissolved from samples under microwave heating,as revealed by the elemental analysis of leachates. Fourier transform infrared spectroscopic analysis also indicates a higher mass transfer coefficient in the diffusion layer of the raw material by microwave irradiation. When Ca F_2 is present,the reaction energy barrier is lowered and the leaching process is controlled by the tightly covered product layer,resulting in a prominent effect of microwave irradiation.
基金Funded by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (ROCS, SEM [2005] No. 383)
文摘A novel process for separation of red (Y2O3:Eu3+), blue(BaMgAl10O17:Eu2+) and green (CeMgAl10O17:Tb3) rare earth fluorescent powders was proposed. At first, the blue powder can be extracted selectively from an aqueous solution using a chelating collector 2-thenoyltrifluoroacetone (TTA) dissolved in heptane at alkaline pH condition, then, chloroform was used for extracting the green powder into organic phase. The red phosphor remains in aqueous phase with potassium sodium tartrate depressant (PST). Therefore, three phosphors can be separated successfully from their artificial mixtures by liquid/liquid extraction, and grades and recovery of separated products reach respectively as follows: red is 96.9% and 95.2%, blue is 82.7% and 98.8%, green is 94.6% and 82.6%.
基金Funded by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (ROCS, SEM [2005] No. 383)
文摘A novel process for separation of red (Y2O3: Eu3+), blue (Sr, Ca, Ba)10(PO4)6Cl2: Eu2+ and green (LaPO4: Tb3+, Ce3+) fine tricolor phosphor powders was established. First, the green phosphor was extracted and separated from three phosphor mixtures in heptane/DMF(N, N-Dimethylformamide) system using stearylamine or laurylamine (DDA) as the cationic surfactant. Then, after being treated with 99.5% ethanol, the blue and red phosphors could be separated in Heptane/DMF system in presence of 1-octanesulfonic acid sodium salt as the anionic surfactant. Satisfactory separation results have been achieved through two steps extractions with their artificial mixtures. The grades and recovery of separated products reached respectively as follows: red product was 95.3% and 90.9%, blue product was 90.0% and 95.2%, and green product was 92.2% and 91.8%.
文摘Seedling period is an important stage of plant growth. This research was mainly to analysis the influence of chitosan on wheat seedling growth and physiological mechanisms under drought stress. The results showed that the group coated with chitosan significantly improved the growth index such as germination rate, wet weight, root length, root active, and impacted physiological indices such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)), the content of malwondialdehyde (MDA) and chlorophyll compared with CK under drought stress. Activities of POD, CAT and SOD increased and then decreased, the content of MDA increased under drought stress. But. variation rates of the group coated with chitosan were slower than that of CK, which indicates that chitosan can significantly improve anti-oxidant enzymes activity to clear timely active oxygen and reduce the content of MDA so as to alleviate the degree of damage in the drought stress and make seedlings grow better. The results also showed that chitosan improved chloro-phyll content than that of CK, which demonstrated that chlorophyll content significantly influenced the photosynthetic efficiency of the mutant and added wheat above ground biomass and the field experiment results showed that chitosan increased yield 13.6% than that of CK.
文摘We used the no pollution natural polymer polysaccharide chitosan as the main raw material, which is supplemented by other additives, to prepare a high-efficiency environmental friendly maize seed coating agent. By detecting the seed quality, maize seedling indexes, which include root activity, chlorophyll content and malondialdehyde (MDA) content, and through the results we found that this seed coating agent could improve the photosynthetic capacity and enhance seedling resistance. Laboratory bacteriostasis test and study showed that the antibacterial rate of this seed coating agent has reached more than 88%. Meanwhile, we analyzed and studied the antimicrobial mechanism of the seed coating agent.
文摘By using acrylic acid copolymer, sodium citrate, hydrolyzed polymaleic anhydride (HPMA), corrosion inhibitor D and Zn2+ synergist as raw materials, a multi-component phosphate-free corrosion and scale inhibitor was developed. The performance of the composite phosphate-free corrosion and scale inhibitor was evaluated using the rotary hanging sheet corrosion test, the static scale inhibition test and the corrosion electrochemical test. And the surface morphology of the carbon steel was observed by scanning electronic microscope (SEM). Orthogonal experiment results indicated that the optimal mass ratios of amino acid: Zn2+ synergist: HPMA: corrosion inhibitor D: acrylic acid copolymer was 0.5:10:12:1:8. It was also observed that phosphate-free corrosion and scale inhibitor based on an anodic reaction through the electrochemical corrosion experiment, its annual corrosion rate and scale inhibition rate reached 0.0176 mm·a–1 and 98.3%, respectively, showing excellent corrosion and scale inhibition performance.
基金Projects(2013BAB02B01,2013BAB02B03)supported by the National Key Technologies R&D Program of ChinaProjects(41072224,41272347)supported by the National Natural Science Foundation of China
文摘Geomechanical parameters are complex and uncertain.In order to take this complexity and uncertainty into account,a probabilistic back-analysis method combining the Bayesian probability with the least squares support vector machine(LS-SVM) technique was proposed.The Bayesian probability was used to deal with the uncertainties in the geomechanical parameters,and an LS-SVM was utilized to establish the relationship between the displacement and the geomechanical parameters.The proposed approach was applied to the geomechanical parameter identification in a slope stability case study which was related to the permanent ship lock within the Three Gorges project in China.The results indicate that the proposed method presents the uncertainties in the geomechanical parameters reasonably well,and also improves the understanding that the monitored information is important in real projects.
基金jointly supported by the National Natural Science Foundation,China(41907124,3210130653,51908233)Program for Innovative Research Team of Excellent Middle-Aged and Young in Higher Education Institutions of Hubei Province(T2021011)+2 种基金Nature Science Foundation of Hubei Province,China(2020CFB465)Educational Commission of Hubei Province,China(D20202503)Open Fund of Research Center for Transition and Development of Resources-exhausted City,China(KF2020Z03)。
文摘Phosphorus(P)in surface runoff from purple soil is a critical element of agricultural nonpoint source pollution,leading to eutrophication of surface waters in the Three Gorges Reservoir Area(TGRA)of China.This work aimed to understand the processes and mechanisms of P losses from bare purple soil.Based on an indoor rainfall simulation experiment,we focused on the processes of surface runoff and P losses via different hydrological pathways.Experimental treatments included three simulated rainfall intensities,four slope gradients,and three fertilizer treatments.P loss from sediment was the main pathway in the purple soil,and bioavailable P was mainly transferred in dissolved P(DP)of runoff water.The P loss loads tend to grow with the increase of the slope until 25°for the maximum load of runoff water and 20°for the maximum load of sediment.Concentrations of DP in the surface runoff after fertilizer application can exceed the estimates of those required for accelerated eutrophication.Sediment P control might be an essential way for reducing P loss in purple soil for the local government and farmers of TGRA.
基金National Natural Science Foundation of China under Grant Nos.52064015 and 51404111Jiangxi Provincial Natural Science Foundation under Grant No.20192BAB206017+1 种基金Scientific Research Project of Jiangxi Provincial Education Department under Grant No.GJJ160643the Program of Qingjiang Excellent Young Talents,Jiangxi University of Science and Technology under Grant No.JXUSTQJYX2016007。
文摘In the present study of peak particle velocity(PPV)and frequency,an improved algorithm(principal empirical mode decomposition,PEMD)based on principal component analysis(PCA)and empirical mode decomposition(EMD)is proposed,with the goal of addressing poor filtering de-noising effects caused by the occurrences of modal aliasing phenomena in EMD blasting vibration signal decomposition processes.Test results showed that frequency of intrinsic mode function(IMF)components decomposed by PEMD gradually decreases and that the main frequency is unique,which eliminates the phenomenon of modal aliasing.In the simulation experiment,the signal-to-noise(SNR)and root mean square errors(RMSE)ratio of the signal de-noised by PEMD are the largest when compared to EMD and ensemble empirical mode decomposition(EEMD).The main frequency of the de-noising signal through PEMD is 75 Hz,which is closest to the frequency of the noiseless simulation signal.In geotechnical engineering blasting experiments,compared to EMD and EEMD,the signal de-noised by PEMD has the lowest level of distortion,and the frequency band is distributed in a range of 0-64 Hz,which is closest to the frequency band of the blasting vibration signal.In addition,the proportion of noise energy was the lowest,at 1.8%.
基金supported by National Natural Science Foundation of China(Grant No. 21276199)Doctoral Program of Ministry of Education of China(Grant No. 20070247055)+2 种基金Program for Young Excellent Talents in Tongji University of China(Grant No. 2006KJ022)Shanghai Municipal Leading Academic Discipline Program of China(Grant No. B303)111 Project of China(Grant No. B08019)
文摘Water plays a critical role on the performance, stability and lifetime of proton exchange membrane fuel cells(PEMFCs). The addition of poly tetrafluoroethylene(PTFE) to the gas diffusion layer, especially, the cathode side, would optimize the transportation of water, electron and gas and thus improve the performance of the fuel cell. But until now, the studies about directly applying the PTFE to the catalyst layer are rarely reported. In this paper, the membrane electrode is fabricated by using directly coating catalyst to the membrane method(CCM) and applying PTFE directly to the cathode electrode catalyst layer. The performance of the single cell is determined by polarization curves and durability tests. Electrochemical impedance spectroscopy(EIS) and scanning electron microscopy(SEM) techniques are used to characterize the electrochemical properties of PEMFC. Also the performance of a 10-cells stack is detected. Combining the performance and the physical-chemistry characterization of PEMFC shows that addition of appropriate content of PTFE to the electrode enhances the performance of the fuel cell, which may be due to the improved water management. Addition of appropriate content of PTFE enhances the interaction between the membrane and the catalyst layer, and bigger pores and highly textured structure form in the MEA, which favors the oxygen mass transfer and protons transfer in the fuel cell. While superfluous addition of PTFE covers the surface of catalysts and hindered the contact of catalyst with Nafion, which leads to the reduction of electrochemical active area and the decay of the fuel cell performance. The proposed research would optimize the water management of the fuel cell and thus improve the performance of the fuel cell.
基金supported by grants from Debra and Arlen Prentice,Central Washington University School of Graduate Studies and Research,National Science Foundation(NSF)International Research Experiences for Students(IRES)(OISE1065589)National Science Foundation of China(31372215,31672307)
文摘Play behaviors and signals during playful interactions with juvenile conspecifics are important for both the social and cognitive development of young animals.The social organization of a species can also influence juvenile social play. We examined the relationships among play behaviors, candidate play signals, and play bout termination in Tibetan macaques(Macaca thibetana) during juvenile and infant social play to characterize the species play style. As Tibetan macaques are despotic and live in groups with strict linear dominance hierarchies and infrequent reconciliation, we predicted that play would be at risk of misinterpretation by both the individuals engaged in the play bout and by those watching, possibly leading to injury of the players. Animals living in such societies might need to frequently and clearly signal playful intent to play partners and other group members to avoid aggressive outcomes. We gathered video data on 21 individually-identified juvenile and infant macaques(one month to five years of age)from the Valley of the Wild Monkeys, Mt. Huangshan,China. We used all-occurrence sampling to record play behaviors and candidate play signals based on an ethogram. We predicted that play groups would use multiple candidate play signals in a variety of contexts and in association with the number of audience members in proximity to the players and play bout length. In the 283 playful interactions we scored,juvenile and infant macaques used multiple body and facial candidate play signals. Our data showed that juvenile and infant Tibetan macaques use a versatile repertoire of play behaviors and signals to sustain play.
基金This study was financially supported by the National Natural Science Foundation of China(51579062,51379147),which is gratefully appreciated.
文摘The mechanical behaviors and energy dissipation characteristics of heat-treated granite were investigated under repeated impact loading.The granite samples were firstly heat-treated at the temperature of 20℃,200℃,400℃,and 600℃,respectively.The thermal damage characteristics of these samples were then observed and measured before impact tests.Dynamic impact compression tests finally were carried out using a modified split-Hopkinson pressure bar under three impact velocities of 12 m/s,15 m/s,and 18 m/s.These test results show that the mineral composition and the main oxides of the granite do not change with these treatment temperatures.The number of microcracks and microvoids decreases in the sample after 200℃ treatment.The mechanical properties of a sample after 600℃ treatment were rapidly deteriorated under the same impact velocity.The average of peak stress is much smaller than those after 20℃,200℃ and 400℃ treatments.The heat-treated samples have an energy threshold each.When the dissipated energy of a sample under a single impact is less than this threshold,the repeated impacts hardly lead to further damage accumulation even if its total breakage energy dissipation(BED)density is large.Under the same number of repeated impacts,the cumulative BED density of a sample after 600℃ treatment is the largest and its damage evolves most quickly.The total BED density of the sample after 200℃ treatment is the highest,which implies that this sample has better resistance to repeated impact,thus having less crack initiation and growth.
文摘In the study, a novel environmental soybean seed coating agent was made of natural polymer, trace elements, trace fertilizer and biopesticides etc., with the condition of high performance-to-price ratio and environmental friendliness. Effects of this soybean seed coating agent on soybean yield were tested through the laboratory and farm experiments. The tested results showed that the soybean yield using this seed coating agent was increased by 15.46%, and its cost was decreased by 27.8%, compared with the conventional soybean seed coating agent. It’s nontoxic and harmless to human and animals, more friendly to the environment. So it has obvious economic and environmental benefits.
基金supported by the National Natural Science Foundation of China(No.51904211)the National Natural Science Foundation of China(No.52004187)。
文摘Microwave heating can rapidly and uniformly raise the temperature and accelerate the reaction rate.In this paper,microwave heating was used to improve the acid leaching,and the mechanism was investigated via microscopic morphology analysis and numerical simulation by COMSOL Multiphysics software.The effects of the microwave power,leaching temperature,CaF_(2) dosage,H_(2)SO_(4) concentration,and leaching time on the vanadium recovery were investigated.A vanadium recovery of 80.66%is obtained at a microwave power of 550 W,leaching temperature of 95℃,CaF_(2) dosage of 5wt%,H_(2)SO_(4) concentration of 20vol%,and leaching time of 2.5 h.Compared with conventional leaching technology,the vanadium recovery increases by 6.18%,and the leaching time shortens by 79.17%.More obvious pulverization of shale particles and delamination of mica minerals happen in the microwave-assisted leaching process.Numerical simulation results show that the temperature of vanadium shales increases with an increase in electric field(E-field).The distributions of E-field and temperature among vanadium shale particles are relatively uniform,except for the higher content at the contact position of the particles.The analysis results of scaleup experiments and leaching experiments indicate high-temperature hot spots in the process of microwave-assisted leaching,and the local high temperature destroys the mineral structure and accelerates the reaction rate.
