The lime-depressed pyrite from Cu differential flotation tailings with acid mine drainage(AMD)as a natural activator was recovered.The effect of AMD on lime-depressed pyrite flotation was investigated by a series of l...The lime-depressed pyrite from Cu differential flotation tailings with acid mine drainage(AMD)as a natural activator was recovered.The effect of AMD on lime-depressed pyrite flotation was investigated by a series of laboratory flotation tests and surface analytical techniques.Flotation test results indicated that AMD could effectively activate the pyrite flotation with a sodium butyl xanthate(SBX)collector,and a high-quality sulfur concentrate was obtained.Pulp ion concentration analysis results indicated that AMD facilitated desorption of Ca~(2+)and adsorption of Cu~(2+)on the depressed-pyrite surface.Adsorption measurements and contact angle analysis results confirmed that adding AMD improved the adsorption amount of SBX collector on the pyrite surface and increased the contact angle by 31°.Results of Raman spectroscopy and X-ray photoelectron spectroscopy analysis indicated that AMD treatment promoted the formation of hydrophobic species(S~0 hydrophobic entity and copper sulfides)and the removal of hydrophilic calcium and iron species on the pyrite surface,which reinforced the adsorption of collector.The findings of the present research provide important theoretical basis and technical support for a cleaner production of copper sulfide ores.展开更多
Adsorption of water on sulfide surfaces and natural floatability of sulfide minerals were studied using density functional theory (DFT) method. All computational models were built in a vacuum environment to eliminat...Adsorption of water on sulfide surfaces and natural floatability of sulfide minerals were studied using density functional theory (DFT) method. All computational models were built in a vacuum environment to eliminate the effects of oxygen and other factors. H2O molecule prefers to stay with pyrite and sphalerite surfaces rather than water, whereas for galena, chalcocite, stibnite, and molybdenite, H2O molecule prefers to stay with water rather than the mineral surfaces. On the other hand, pyrite surface favors N2 more than water, while sphalerite surface cannot adsorb N2. These results show that galena, stibnite, chalcocite, and molybdenite are hydrophobic, while sphalerite is hydrophilic. Although pyrite has certain hydrophilicity, it tends to be aerophilic because the reaction of pyrite with H2O is weaker than pyrite with N2. Thus, pyrite, galena, chalcocite, stibnite and molybdenite all have natural floatability.展开更多
[Objective] The aim was to research macrobenthos community structure and its relations with environmental factors in three reservoirs. [Method] Benthic diversity and water quality of Yuqiao Reservoir, Beidagang Reserv...[Objective] The aim was to research macrobenthos community structure and its relations with environmental factors in three reservoirs. [Method] Benthic diversity and water quality of Yuqiao Reservoir, Beidagang Reservoir and Er- wangzhuang Reservoir were investigated in May, July and September 2011, respec- tively. []Result] Of all the 14 sampling sites, 22 species of macroinvertebrates were collected, totally, which included 6 species of aquatic insects, 7 species of Mollusca, 2 species of Crustacean, 7 species of Oligochaeta. The species of macroinverte- brates during May, July and September in Yuqiao reservoir were 11, 8 and 10, respectively. The dominant species were Chironomus sinicus, and Monopylephorus limosus. The average density and biomass of the macrobenthos were 132.43 ind./m2 and 50.09 g/m2. Yuqiao reservoir was mostly at status of premediate polluted, according to the Margalef index, Shannon index and Pielou index. The species of during May, July and September in Beidagang reservoir were 5 5 and 5, respectively. The dominant species were Chironomus sinicus, Penaeus vannamei. The average density and biomass of the macrobenthos were 218 ind./m2 and 2.70 g/m2. Beidagang reservoir was mostly at status of heavy polluted, accord- ing to the Margalef index, Shannon-wiener index, Pielou index. The species of during May, July and September in Erwangzhuang reservoir were 3, 5 and 5, respectively. The dominant species were Monopylephorus limosus, Chi- ronomus sinicus. The average density and biomass of the macrobenthos were 104 ind/m2 and 0.20 g/m2. Erwangzhuang reservoir was mostly at status of intermediate polluted, according to the Margalef index, Shannon index, Pielou index. The density of zoobenthos in Yuqiao Reservoir was positively significantly correlated with TP (P〉 0.05), negatively correlated with NH4+-N (P〉0.05), positively correlated with COD (P〈 0.01), not significantly correlated with other environment factors (P〉0.05). There was no significant correlation between biomass of zoobenthos and environment factors. The density of zoobenthos in Beidagang Reservoir with NH4+-N was positively signif- icantly correlated (P〈0.05), not significantly correlated with other aquatic environment factors (P〉0.05). There was no significant correlation between biomass of zoobenthos and environment factors. The density of zoobenthos in Erwangzhuang Reser- voir with NO3-N was positively significantly correlated (P〈0.05), not significant cor- related with other aquatic environment factors (F〉0.05). The biomass of zoobenthos in Erwangzhuang Reservoir with NH4+-N was positively significantly correlated (P〈 0.05), not significant correlated with other aquatic environment factors (P〉0.05). [Conclusion] It is indicated that this three reservoirs were all eutrophied and polluted, and the eurephication extent change of water in three reservoirs is as follows: Beidagang reservoir〉Erwangzhuang reservoir〉Yuqiao reservoir.展开更多
We investigated the effect of microscopic distribution modes of hydrates in porous sediments, and the saturation of hydrates and free gas on the elastic properties of saturated sediments. We simulated the propagation ...We investigated the effect of microscopic distribution modes of hydrates in porous sediments, and the saturation of hydrates and free gas on the elastic properties of saturated sediments. We simulated the propagation of seismic waves in gas hydrate-bearing sediments beneath the seafloor, and obtained the common receiver gathers of compressional waves(P-waves) and shear waves(S-waves). The numerical results suggest that the interface between sediments containing gas hydrates and free gas produces a large-amplitude bottomsimulating reflector. The analysis of multicomponent common receiver data suggests that ocean-bottom seismometers receive the converted waves of upgoing P- and S-waves, which increases the complexity of the wavefield record.展开更多
To investigate the distribution and velocity attributes of gas hydrates in the northern continental slope of South China Sea, Guangzhou Marine Geological Survey conducted four-component (4C) ocean-bottom seismometer...To investigate the distribution and velocity attributes of gas hydrates in the northern continental slope of South China Sea, Guangzhou Marine Geological Survey conducted four-component (4C) ocean-bottom seismometer (OBS) surveys. A case study is presented to show the results of acquiring and processing OBS data for detecting gas hydrates. Key processing steps such as repositioning, reorientation, PZ summation, and mirror imaging are discussed. Repositioning and reorientation find the correct location and direction of nodes. PZ summation matches P- and Z-components and sums them to separate upgoing and downgoing waves. Upgoing waves are used in conventional imaging, whereas downgoing waves are used in mirror imaging. Mirror imaging uses the energy of the receiver ghost reflection to improve the illumination of shallow structures, where gas hydrates and the associated bottom-simulating reflections (BSRs) are located. We developed a new method of velocity analysis using mirror imaging. The proposed method is based on velocity scanning and iterative prestack time migration. The final imaging results are promising. When combined with the derived velocity field, we can characterize the BSR and shallow structures; hence, we conclude that using 4C OBS can reveal the distribution and velocity attributes of gas hydrates.展开更多
According to the processing and interpretation of multichannel seismic reflection data in the area of Okinawa Trough, the BSR (bottom simulating reflector) was identified in 16 seismic profiles. By means of special ...According to the processing and interpretation of multichannel seismic reflection data in the area of Okinawa Trough, the BSR (bottom simulating reflector) was identified in 16 seismic profiles. By means of special processing technologies such as AVO and waveform inversion, the authors, for the first time, directly used the BSR to outline the distribution tendency of thickness of gas hydrate stability zone in the Trough and thought that the largest stability zone thickness was in the south and the smallest in the north. Then through calculation the authors got the thickness of hydrate stability zone and resource of the hydrate. This would be useful to the future hydrate exploration and resource evaluation in the Okinawa Trough.展开更多
Nuclear magnetic resonance measurements in hydrate-bearing sandstone samples from the Shenhu area, South China Sea were used to study the effect of gas hydrates on the sandstone permeability. The hydrate-bearing sampl...Nuclear magnetic resonance measurements in hydrate-bearing sandstone samples from the Shenhu area, South China Sea were used to study the effect of gas hydrates on the sandstone permeability. The hydrate-bearing samples contain pore-filling hydrates. The data show that the pore-filling hydrates greatly affect the formation permeability while depending on many factors that also bear on permeability; furthermore, with increasing hydrate saturation, the formation permeability decreases. We used the Masuda model and an exponent N = 7.9718 to formulate the empirical equation that describes the relation between relative permeability and hydrate saturation for the Shenhu area samples.展开更多
A new high-efficiency farming method of global significance, Fenlong tech- nique capable of making soil fertile, increasing yield and improving ecological envi- ronment was introduced; and the Fenlong technique could ...A new high-efficiency farming method of global significance, Fenlong tech- nique capable of making soil fertile, increasing yield and improving ecological envi- ronment was introduced; and the Fenlong technique could deeply plough and scarify soil with a depth up to 30-50 cm, which is deeper than the depth of tractor tillage, solving the problem of difficulties in deeply ploughing and scarifying soil and keeping soil loose for muttiple seasons. The application to 20 crops in 18 provinces proved that yield could be increased by 10%-30% without increase in chemical fertilizer, quality could be improved by more than 5%, and water storage could be increased by 100%; yield could be increased for multiple seasons sustainably, and the yield of dry-land crops increased by 32.57%-38.2% from the second year to the fourth year; the net benefits of rice increased by 21.82% averagely from the first season to the sixth season; and the usage amount of chemical fertilizer decreased by 0.35-4.29 kg per 100 kg produced grain compared with conventional tillage, with an decrease amplitude of 10.81%-30.99%. It was discussed that the Fenlong technique could maximize friendly permanently-sustainable unitization of "natural resources" including soil nutrients, water, oxygen and light energy, and has good development potential in multiple fields. It was put forward that if it is popularized in 0.67x108 hm2, pro- ductivity of farmland could be newly increased by 0.1-0.13×10^8 hm2, 5.0 ×10^6 t of chemical fertilizer could be saved, the' storage of agricultural water could be in- creased by 3.0×10^10 m3, and increased food could feed 2,0-3.0×10^8 people.展开更多
Bottom-simulating reflectors (BSRs) in seismic profile always indicate the bottom of gas hydrate stability zone, but is difficult to determine the distribution and features of gas hydrate sediments (GHS). In this stud...Bottom-simulating reflectors (BSRs) in seismic profile always indicate the bottom of gas hydrate stability zone, but is difficult to determine the distribution and features of gas hydrate sediments (GHS). In this study, based on AVA forward modeling and angle-domain common-image gathers we use prestack AVA parameters consistency inversion in predicting gas hydrate sediments in the Shenhu area at northern slope of South China Sea, and obtain the vertical and lateral features and saturation of GHS.展开更多
Environmental endocrine disrupting chemicals (EDCs), commonly found in the environment, come from industry and agriculture, including pesticides, fungicides, insecticides, herbicides, and other chemicals. Nowadays, ...Environmental endocrine disrupting chemicals (EDCs), commonly found in the environment, come from industry and agriculture, including pesticides, fungicides, insecticides, herbicides, and other chemicals. Nowadays, more and more EDCs were released into the environment. EDCs go into water body via atmosphere sedi-mentation, surface runoff, soil eluviation, etc., so water body becomes the main place for existing. In order to attract scientific and public attention worldwide and to prevent EDCs pol ution, in this study we reviewed the classification of EDCs and their concentrations in natural water bodies, drinking water sources and water plants, and the reproductive toxicity of EDCs to fish were reviewed. EDCs could disturb the endocrine system and make reproductive organs and reproduction abnor-mal, resulting in fertility descending, reproduction function damage, community quan-tity decrease and even species extinction. In addition, EDCs could disrupt the homeostasis maintained by hormones, which would result in defects of neural de-velopment and abnormalities of the endocrine and reproductive systems. The exact molecular mechanisms have not been completely reported, but researches have suggested that multiple mechanisms were involved in the action of EDCs. Although there have been researches on the biohazard of EDCs, there stil exist problems of weakness in fundamental researches, difficulties in recognizing and identifying EDCs and high cost, which restraint the knowledge on them.展开更多
The sulfate-methane interface is an important biogeochemical identification interface for the areas with high methane flux and containing gas hydrate. Above the sulfate-methane interface, the sulfate concentration in ...The sulfate-methane interface is an important biogeochemical identification interface for the areas with high methane flux and containing gas hydrate. Above the sulfate-methane interface, the sulfate concentration in the sediment is consumed progressively for the decomposition of the organic matter and anaerobic methane oxidation. Below the sulfate-methane interface, the methane concentration increases continuously with the depth. Based on the variation characters of the sulfate and methane concentration around the sulfate-methane interface, it is feasible to estimate the intensity of the methane flux, and thereafter to infer the possible occurrence of gas hydrate. The geochemical data of the pore water taken from the northern slope of the South China Sea show the sulfate-methane interface is relatively shallow, which indicates that this area has the high methane flux. It is considered that the high methane flux is most probably caused by the occurrence of underlying gas hydrate in the northern slope of the South China Sea.展开更多
[ Objective] This study was to improve the biomass of Navicula tenera, and thus to provide reference for achieving the industrial production of Navicula tenera. [Method] The feasibility of using sewage to cultivate Na...[ Objective] This study was to improve the biomass of Navicula tenera, and thus to provide reference for achieving the industrial production of Navicula tenera. [Method] The feasibility of using sewage to cultivate Navicula tenera was preliminarily investigated based on the consideration of regional characteristics; and a series of culture conditions including the nutrient source of nitrogen(N), phosphorus(P), iron(Fe), silicon( Si ) and the salinity in medium for culturing Navicula tenera, were optimized by single factor test and orthogonal design.[Result] The optimized conditions for cultivating Navicula tenera using sewage are as follows: the water from Xiaoerlou Artificial Lake of Nanjing University of Technology as basic solvent; 360 mg/L urea; 150 mg/L N2HPO4 · 12H2O; 50 mg/L ferric citrate; 2 000 mg/L Na2SiO3 · 9H2O; 2.0 mol/L salinity. Navicula tenera was strongly adaptive to sewage and could well uptake the nutrient sources in the sewage. Under the optimized conditions, the culture cost decreased, and meanwhile the biomass of Navicula tenera reached 4. 766 g/L which is 3.57 multiples over original medium and 1.9 multiples over optimized medium No. 1.[ Conclusion] This study laid a foundation for the combination of culturing Navicula tenera in large scale and sewage treatment.展开更多
The ecological nature of Ferirana guadranus in Liqiao Country of Tianshui City of Guansu Province from May to August in 2010 are primarily investigated.Research found that Ferirana guadranus lives in the mountain stre...The ecological nature of Ferirana guadranus in Liqiao Country of Tianshui City of Guansu Province from May to August in 2010 are primarily investigated.Research found that Ferirana guadranus lives in the mountain streams at an elevation of 1 332 m.The adult frog lives largely above an elevation of 1 320 m,where the water is neutral acid and shady.It belongs to the mountainous stream type.展开更多
Gas hydrate is a kind of icy crystal body formed by water and natural gas in special conditions. The discovery of gas hydrates provides a wide sphere and a new way of thinking for finding clean and effective energy re...Gas hydrate is a kind of icy crystal body formed by water and natural gas in special conditions. The discovery of gas hydrates provides a wide sphere and a new way of thinking for finding clean and effective energy resources to replace increasingly exhausted traditional energy resources. Moreover, in our country there are a wide realm and bright prospect in the exploration of gas hydrate. This paper has summarized the progress on the study of gas hydrate. And based on the former research about gas hydrates, the integrative identification signs of gas hydrates were summarized in the aspects of seismic data, geophysical well logging, sedimentary and rock, geochemistry, topography and morphology. In the end, the author hopes it may provide some useful clues to the exploration of gas hydrate.展开更多
基金financially supported from the National Natural Science Foundation of China(No.52164021)the Natural Science Foundation of Yunnan Province,China(No.2019FB078)。
文摘The lime-depressed pyrite from Cu differential flotation tailings with acid mine drainage(AMD)as a natural activator was recovered.The effect of AMD on lime-depressed pyrite flotation was investigated by a series of laboratory flotation tests and surface analytical techniques.Flotation test results indicated that AMD could effectively activate the pyrite flotation with a sodium butyl xanthate(SBX)collector,and a high-quality sulfur concentrate was obtained.Pulp ion concentration analysis results indicated that AMD facilitated desorption of Ca~(2+)and adsorption of Cu~(2+)on the depressed-pyrite surface.Adsorption measurements and contact angle analysis results confirmed that adding AMD improved the adsorption amount of SBX collector on the pyrite surface and increased the contact angle by 31°.Results of Raman spectroscopy and X-ray photoelectron spectroscopy analysis indicated that AMD treatment promoted the formation of hydrophobic species(S~0 hydrophobic entity and copper sulfides)and the removal of hydrophilic calcium and iron species on the pyrite surface,which reinforced the adsorption of collector.The findings of the present research provide important theoretical basis and technical support for a cleaner production of copper sulfide ores.
基金Project(51164001)supported by the National Natural Science Foundation of ChinaProject(NCET-11-0925)supported by New Century Excellent Talents in University,China
文摘Adsorption of water on sulfide surfaces and natural floatability of sulfide minerals were studied using density functional theory (DFT) method. All computational models were built in a vacuum environment to eliminate the effects of oxygen and other factors. H2O molecule prefers to stay with pyrite and sphalerite surfaces rather than water, whereas for galena, chalcocite, stibnite, and molybdenite, H2O molecule prefers to stay with water rather than the mineral surfaces. On the other hand, pyrite surface favors N2 more than water, while sphalerite surface cannot adsorb N2. These results show that galena, stibnite, chalcocite, and molybdenite are hydrophobic, while sphalerite is hydrophilic. Although pyrite has certain hydrophilicity, it tends to be aerophilic because the reaction of pyrite with H2O is weaker than pyrite with N2. Thus, pyrite, galena, chalcocite, stibnite and molybdenite all have natural floatability.
基金Supported by Tianjin Aquatic Species Diveristy Surveying,Monitoring and Evaluation Proejct~~
文摘[Objective] The aim was to research macrobenthos community structure and its relations with environmental factors in three reservoirs. [Method] Benthic diversity and water quality of Yuqiao Reservoir, Beidagang Reservoir and Er- wangzhuang Reservoir were investigated in May, July and September 2011, respec- tively. []Result] Of all the 14 sampling sites, 22 species of macroinvertebrates were collected, totally, which included 6 species of aquatic insects, 7 species of Mollusca, 2 species of Crustacean, 7 species of Oligochaeta. The species of macroinverte- brates during May, July and September in Yuqiao reservoir were 11, 8 and 10, respectively. The dominant species were Chironomus sinicus, and Monopylephorus limosus. The average density and biomass of the macrobenthos were 132.43 ind./m2 and 50.09 g/m2. Yuqiao reservoir was mostly at status of premediate polluted, according to the Margalef index, Shannon index and Pielou index. The species of during May, July and September in Beidagang reservoir were 5 5 and 5, respectively. The dominant species were Chironomus sinicus, Penaeus vannamei. The average density and biomass of the macrobenthos were 218 ind./m2 and 2.70 g/m2. Beidagang reservoir was mostly at status of heavy polluted, accord- ing to the Margalef index, Shannon-wiener index, Pielou index. The species of during May, July and September in Erwangzhuang reservoir were 3, 5 and 5, respectively. The dominant species were Monopylephorus limosus, Chi- ronomus sinicus. The average density and biomass of the macrobenthos were 104 ind/m2 and 0.20 g/m2. Erwangzhuang reservoir was mostly at status of intermediate polluted, according to the Margalef index, Shannon index, Pielou index. The density of zoobenthos in Yuqiao Reservoir was positively significantly correlated with TP (P〉 0.05), negatively correlated with NH4+-N (P〉0.05), positively correlated with COD (P〈 0.01), not significantly correlated with other environment factors (P〉0.05). There was no significant correlation between biomass of zoobenthos and environment factors. The density of zoobenthos in Beidagang Reservoir with NH4+-N was positively signif- icantly correlated (P〈0.05), not significantly correlated with other aquatic environment factors (P〉0.05). There was no significant correlation between biomass of zoobenthos and environment factors. The density of zoobenthos in Erwangzhuang Reser- voir with NO3-N was positively significantly correlated (P〈0.05), not significant cor- related with other aquatic environment factors (F〉0.05). The biomass of zoobenthos in Erwangzhuang Reservoir with NH4+-N was positively significantly correlated (P〈 0.05), not significant correlated with other aquatic environment factors (P〉0.05). [Conclusion] It is indicated that this three reservoirs were all eutrophied and polluted, and the eurephication extent change of water in three reservoirs is as follows: Beidagang reservoir〉Erwangzhuang reservoir〉Yuqiao reservoir.
基金supported by the National Natural Science Foundation of China(No.41174087,41204089)the National Oil and Gas Major Project(No.2011ZX05005-005)
文摘We investigated the effect of microscopic distribution modes of hydrates in porous sediments, and the saturation of hydrates and free gas on the elastic properties of saturated sediments. We simulated the propagation of seismic waves in gas hydrate-bearing sediments beneath the seafloor, and obtained the common receiver gathers of compressional waves(P-waves) and shear waves(S-waves). The numerical results suggest that the interface between sediments containing gas hydrates and free gas produces a large-amplitude bottomsimulating reflector. The analysis of multicomponent common receiver data suggests that ocean-bottom seismometers receive the converted waves of upgoing P- and S-waves, which increases the complexity of the wavefield record.
基金supported by the National Hi-tech Research and Development Program of China(863 Program)(Grant No.2013AA092501)the China Geological Survey Projects(Grant Nos.GZH201100303 and GZH201100305)
文摘To investigate the distribution and velocity attributes of gas hydrates in the northern continental slope of South China Sea, Guangzhou Marine Geological Survey conducted four-component (4C) ocean-bottom seismometer (OBS) surveys. A case study is presented to show the results of acquiring and processing OBS data for detecting gas hydrates. Key processing steps such as repositioning, reorientation, PZ summation, and mirror imaging are discussed. Repositioning and reorientation find the correct location and direction of nodes. PZ summation matches P- and Z-components and sums them to separate upgoing and downgoing waves. Upgoing waves are used in conventional imaging, whereas downgoing waves are used in mirror imaging. Mirror imaging uses the energy of the receiver ghost reflection to improve the illumination of shallow structures, where gas hydrates and the associated bottom-simulating reflections (BSRs) are located. We developed a new method of velocity analysis using mirror imaging. The proposed method is based on velocity scanning and iterative prestack time migration. The final imaging results are promising. When combined with the derived velocity field, we can characterize the BSR and shallow structures; hence, we conclude that using 4C OBS can reveal the distribution and velocity attributes of gas hydrates.
文摘According to the processing and interpretation of multichannel seismic reflection data in the area of Okinawa Trough, the BSR (bottom simulating reflector) was identified in 16 seismic profiles. By means of special processing technologies such as AVO and waveform inversion, the authors, for the first time, directly used the BSR to outline the distribution tendency of thickness of gas hydrate stability zone in the Trough and thought that the largest stability zone thickness was in the south and the smallest in the north. Then through calculation the authors got the thickness of hydrate stability zone and resource of the hydrate. This would be useful to the future hydrate exploration and resource evaluation in the Okinawa Trough.
基金supported by the Key Program for International S&T Cooperation Projects of China(No.2010DFA21630)the National Natural Science Foundation of China(No.41306050)
文摘Nuclear magnetic resonance measurements in hydrate-bearing sandstone samples from the Shenhu area, South China Sea were used to study the effect of gas hydrates on the sandstone permeability. The hydrate-bearing samples contain pore-filling hydrates. The data show that the pore-filling hydrates greatly affect the formation permeability while depending on many factors that also bear on permeability; furthermore, with increasing hydrate saturation, the formation permeability decreases. We used the Masuda model and an exponent N = 7.9718 to formulate the empirical equation that describes the relation between relative permeability and hydrate saturation for the Shenhu area samples.
基金Supported by Special Fund for Basic Scientific Research of Guangxi Academy of Agricultural Sciences(2014YZ07)Scientific and Technological Transformative Project of Guangxi Academy of Agricultural Sciences(201405)CARS-12-Seedling Propagation Post~~
文摘A new high-efficiency farming method of global significance, Fenlong tech- nique capable of making soil fertile, increasing yield and improving ecological envi- ronment was introduced; and the Fenlong technique could deeply plough and scarify soil with a depth up to 30-50 cm, which is deeper than the depth of tractor tillage, solving the problem of difficulties in deeply ploughing and scarifying soil and keeping soil loose for muttiple seasons. The application to 20 crops in 18 provinces proved that yield could be increased by 10%-30% without increase in chemical fertilizer, quality could be improved by more than 5%, and water storage could be increased by 100%; yield could be increased for multiple seasons sustainably, and the yield of dry-land crops increased by 32.57%-38.2% from the second year to the fourth year; the net benefits of rice increased by 21.82% averagely from the first season to the sixth season; and the usage amount of chemical fertilizer decreased by 0.35-4.29 kg per 100 kg produced grain compared with conventional tillage, with an decrease amplitude of 10.81%-30.99%. It was discussed that the Fenlong technique could maximize friendly permanently-sustainable unitization of "natural resources" including soil nutrients, water, oxygen and light energy, and has good development potential in multiple fields. It was put forward that if it is popularized in 0.67x108 hm2, pro- ductivity of farmland could be newly increased by 0.1-0.13×10^8 hm2, 5.0 ×10^6 t of chemical fertilizer could be saved, the' storage of agricultural water could be in- creased by 3.0×10^10 m3, and increased food could feed 2,0-3.0×10^8 people.
文摘Bottom-simulating reflectors (BSRs) in seismic profile always indicate the bottom of gas hydrate stability zone, but is difficult to determine the distribution and features of gas hydrate sediments (GHS). In this study, based on AVA forward modeling and angle-domain common-image gathers we use prestack AVA parameters consistency inversion in predicting gas hydrate sediments in the Shenhu area at northern slope of South China Sea, and obtain the vertical and lateral features and saturation of GHS.
基金Supported by the China Agriculture Research System(CARS49)~~
文摘Environmental endocrine disrupting chemicals (EDCs), commonly found in the environment, come from industry and agriculture, including pesticides, fungicides, insecticides, herbicides, and other chemicals. Nowadays, more and more EDCs were released into the environment. EDCs go into water body via atmosphere sedi-mentation, surface runoff, soil eluviation, etc., so water body becomes the main place for existing. In order to attract scientific and public attention worldwide and to prevent EDCs pol ution, in this study we reviewed the classification of EDCs and their concentrations in natural water bodies, drinking water sources and water plants, and the reproductive toxicity of EDCs to fish were reviewed. EDCs could disturb the endocrine system and make reproductive organs and reproduction abnor-mal, resulting in fertility descending, reproduction function damage, community quan-tity decrease and even species extinction. In addition, EDCs could disrupt the homeostasis maintained by hormones, which would result in defects of neural de-velopment and abnormalities of the endocrine and reproductive systems. The exact molecular mechanisms have not been completely reported, but researches have suggested that multiple mechanisms were involved in the action of EDCs. Although there have been researches on the biohazard of EDCs, there stil exist problems of weakness in fundamental researches, difficulties in recognizing and identifying EDCs and high cost, which restraint the knowledge on them.
文摘The sulfate-methane interface is an important biogeochemical identification interface for the areas with high methane flux and containing gas hydrate. Above the sulfate-methane interface, the sulfate concentration in the sediment is consumed progressively for the decomposition of the organic matter and anaerobic methane oxidation. Below the sulfate-methane interface, the methane concentration increases continuously with the depth. Based on the variation characters of the sulfate and methane concentration around the sulfate-methane interface, it is feasible to estimate the intensity of the methane flux, and thereafter to infer the possible occurrence of gas hydrate. The geochemical data of the pore water taken from the northern slope of the South China Sea show the sulfate-methane interface is relatively shallow, which indicates that this area has the high methane flux. It is considered that the high methane flux is most probably caused by the occurrence of underlying gas hydrate in the northern slope of the South China Sea.
基金Supported by National Basic Research Program of China(973 Pro-gram)(2003CB71600)~~
文摘[ Objective] This study was to improve the biomass of Navicula tenera, and thus to provide reference for achieving the industrial production of Navicula tenera. [Method] The feasibility of using sewage to cultivate Navicula tenera was preliminarily investigated based on the consideration of regional characteristics; and a series of culture conditions including the nutrient source of nitrogen(N), phosphorus(P), iron(Fe), silicon( Si ) and the salinity in medium for culturing Navicula tenera, were optimized by single factor test and orthogonal design.[Result] The optimized conditions for cultivating Navicula tenera using sewage are as follows: the water from Xiaoerlou Artificial Lake of Nanjing University of Technology as basic solvent; 360 mg/L urea; 150 mg/L N2HPO4 · 12H2O; 50 mg/L ferric citrate; 2 000 mg/L Na2SiO3 · 9H2O; 2.0 mol/L salinity. Navicula tenera was strongly adaptive to sewage and could well uptake the nutrient sources in the sewage. Under the optimized conditions, the culture cost decreased, and meanwhile the biomass of Navicula tenera reached 4. 766 g/L which is 3.57 multiples over original medium and 1.9 multiples over optimized medium No. 1.[ Conclusion] This study laid a foundation for the combination of culturing Navicula tenera in large scale and sewage treatment.
基金Supported by World Wide Fund for Nature and Vegetation Protection Petty Cash Fund(CN10000815-100592-1.1.02.02)~~
文摘The ecological nature of Ferirana guadranus in Liqiao Country of Tianshui City of Guansu Province from May to August in 2010 are primarily investigated.Research found that Ferirana guadranus lives in the mountain streams at an elevation of 1 332 m.The adult frog lives largely above an elevation of 1 320 m,where the water is neutral acid and shady.It belongs to the mountainous stream type.
文摘Gas hydrate is a kind of icy crystal body formed by water and natural gas in special conditions. The discovery of gas hydrates provides a wide sphere and a new way of thinking for finding clean and effective energy resources to replace increasingly exhausted traditional energy resources. Moreover, in our country there are a wide realm and bright prospect in the exploration of gas hydrate. This paper has summarized the progress on the study of gas hydrate. And based on the former research about gas hydrates, the integrative identification signs of gas hydrates were summarized in the aspects of seismic data, geophysical well logging, sedimentary and rock, geochemistry, topography and morphology. In the end, the author hopes it may provide some useful clues to the exploration of gas hydrate.