According to the actual conditions in Sanshandao Gold Mine, the cancelling ore pillars mining method was researched. Firstly, a series of tests for the physical and mechanical characteristics of rock mass were carried...According to the actual conditions in Sanshandao Gold Mine, the cancelling ore pillars mining method was researched. Firstly, a series of tests for the physical and mechanical characteristics of rock mass were carried out and a quality classification system of rock mass applied in coastal metal deposit was established. Secondly, the reasonable demarcation depth of cancelling ore pillars was simulated using the finite element method, and the simulation results show that the ore pillars can be cancelled below the level of-555 m. Thirdly, a novel layer-backfill mining method of room-pillar alternation was designed to reduce the disturbance and settlement of terrain in mining area. Engineering practice shows that the new mining method enhanced the mining output and relieved rock disturbance. Furthermore, the settlement of the roof strata was small and no disaster occurred. The new mining technology effectively controlled the deformation of the terrain, indicating that the mining of the large-scale gold coastal deposit in Sanshandao Gold Mine was achieved safely, efficiently, and with a low loss rate.展开更多
Large oilfields are often coincidentally located in major river deltas and wetlands,and potentially damage the structure,function and ecosystem service values of wetlands during oil exploration.In the present study,th...Large oilfields are often coincidentally located in major river deltas and wetlands,and potentially damage the structure,function and ecosystem service values of wetlands during oil exploration.In the present study,the effects of crude oil contamination during oil exploration on soil physical and chemical properties were investigated in marshes of the Momoge National Nature Reserve in Jilin Province,China.The concentrations of total petroleum hydrocarbons in the marsh soil near the oil wells are significantly higher than those in the adjacent control marsh.Soil water contents in oil-contaminated marshes are negatively correlated with soil temperature and are significantly lower than those in the control area,especially in fall.Crude oil contamination significantly increases the soil pH up to8.0,and reduces available phosphorus concentrations in the soil.The concentrations of total organic carbon are significantly different among sampling sites.Therefore,crude oil contamination could potentially alkalinize marsh soils,adversely affect soil fertility and physical properties,and cause deterioration of the marshes in the Momoge National Nature Reserve.Phyto-remediation by planting Calamagrostis angustifolia has the potential to simultaneously restore and remediate the petroleum hydrocarbon-contaminated wetlands.Crude oil contamination affects the soil physical and chemical properties,so developing an effective restoration program in the Momoge wetland is neccesary.展开更多
The sources of marine oil spills are mainly from accidents of marine oil tankers or freighters, marine oil-drilling platforms, marine oil pipelines, marine oilfields, terrestrial pollution, oil-bearing atmosphere, and...The sources of marine oil spills are mainly from accidents of marine oil tankers or freighters, marine oil-drilling platforms, marine oil pipelines, marine oilfields, terrestrial pollution, oil-bearing atmosphere, and offshore oil production equipment. It is concluded upon analysis that there are two main reasons for marine oil spills: (I) The motive for huge economic benefits of oil industry owners and oil shipping agents far surpasses their sense of ecological risks. (II) Marine ecological safety has not become the main concern of national security. Oil spills are disasters because humans spare no efforts to get economic benefits from oil. The present paper draws another conclusion that marine ecological damage caused by oil spills can be roughly divided into two categories: damage to marine resource value (direct value) and damage to marine ecosystem service value (indirect value). Marine oil spills cause damage to marine biological, fishery, seawater, tourism and mineral resources to various extents, which contributes to the lower quality and value of marine resources.展开更多
Petrochemicals play a vital role in the economy of any nation. The products of the industry are the building blocks in many industries as they deepen the forward and backward linkages of the petroleum sector with the ...Petrochemicals play a vital role in the economy of any nation. The products of the industry are the building blocks in many industries as they deepen the forward and backward linkages of the petroleum sector with the rest of the economy. The industry uses a variety of hydrocarbon feedstock such as different cuts of naphtha from refinery and natural gas. One of the problems facing the industry is lack of reliable feedstock supplies. Nigeria has the potential to be a major petrochemicals producer. With proven gas reserves currently estimated at 187 tcf, not much has been accomplished with respect to the effective exploitation and utilization of this resource as most of the nation＇s natural gas production has been flared, liquefied for export or re-injected to enhance greater crude oil recovery. It has become imperative to further find ways to exploit and utilize the nation＇s natural gas reserves and translate it to the improvement of the nation＇s economy. Steam reforming of natural gas is one of the avenues for conversion of natural gas to petrochemicals. This paper, however, reviews various ways of utilizing natural gas, examines the process details of steam reforming of natural gas as a route to optimized natural gas utilization and industrialization in Nigeria. Syngas （synthesis gas） is a versatile feedstock for most petrochemicals and chemical intermediates. Thus utilizing natural gas in this way would strengthen the petrochemical industry making it possible for the country to change from raw materials to value-added products supplier, boost the economy and solve the ＂hydra-headed＂ problem of unemployment in Nigeria with its multiplier employment effect.展开更多
Fish glue is the collagen from scale skin and bone of fish. It is known for value added product from fish processing and the adhesive agent for wood paper book binding etc. This work was aimed with the method to produ...Fish glue is the collagen from scale skin and bone of fish. It is known for value added product from fish processing and the adhesive agent for wood paper book binding etc. This work was aimed with the method to produce fish glue from fish skin through representing optimum fish type and its glue character by study on standard method for fish glue processing （using Oreochromis niloticus skin as the model）, optimum fish type and characterization of the glue from optimum fish skin. Soaking fish skin in 0.1 N NaOH for 6 h and changed it every 3 h for pretreatment before acid extraction with 0.5 M acetic acid was the optimum condition for the standard processing. Among 20 types （O. niloticus, Oreochromis sp., Nemipterus sp., Psettodes erumei, Epiephelus malabaricus, Sphyraena obstsata, Channa striata, Xenentodon cancila, Barbonymus gonionotus, Liza vaigiensis, Anabas testudineus, Chanos chanos, Micronema bleekeri, Thunnus tonggol, Rastrelliger brachysom, Epinephelus lanceolatus, Lutjanus lineolatus, Pomadasys hasta, Selar crumenophthalmus and Sardaorentalis sp.）, Chanos chanos was an appropriate type for glue production. Fat, protein, carbohydrate, moisture, pH and viscosity of Chanos chanos glue were 0.32%, 4.23%, 83.8%, 11.56%, 3.35, 4,978.33-8,180 cp, respectively. The glue was collagen type I which was composed ofal （148 kDa） and a2 （129 kDa） chain and could bind paper, wood and foam sheet.展开更多
AIM:To investigate whether bile duct angulation and T-tube choledochostomy influence the recurrence of choledocholithiasis.METHODS:We conducted a retrospective study including 259 patients who underwent endoscopic sph...AIM:To investigate whether bile duct angulation and T-tube choledochostomy influence the recurrence of choledocholithiasis.METHODS:We conducted a retrospective study including 259 patients who underwent endoscopic sphincterotomy and cholecystectomy for choledocholithiasis between 2000 and 2007.The imaginary line was drawn along the center of the bile duct and each internal angle was measured at the two angulation sites ofthe bile duct respectively.The values of both angles were added together.We then tested our hypothesis by examining whether T-tube choledochostomy was performed and stone recurrence occurred by reviewing each subject's medical records.RESULTS:The overall recurrence rate was 9.3% (24 of 259 patients).The mean value of sums of angles in the recurrence group was 268.3°± 29.6°,while that in the non-recurrence group was 314.8°± 19.9° (P < 0.05).Recurrence rate of the T-tube group was 15.9% (17 of 107),while that of the non T-tube group was 4.6% (7 of 152) (P < 0.05).Mean value of sums of angles after T-tube drainage was 262.5°± 24.6° and that before T-tube drainage was 298.0°± 23.9° in 22 patients (P < 0.05).CONCLUSION:The bile duct angulation and T-tube choledochostomy may be risk factors of recurrence of bile duct stones.展开更多
Among the numerous inland river basins in the arid northwest China,Shiyang River basin is known for its most serious water shortage that constrains its social and economic developments and for some of the worst ecolog...Among the numerous inland river basins in the arid northwest China,Shiyang River basin is known for its most serious water shortage that constrains its social and economic developments and for some of the worst ecological and environmental deterioration in China.The research on the value of water resources used for ecosystem is the basis for reasonable allocation of water resources between users of ecosystem and economic system.In this paper the concept of dynamic value for the ecosystem services is proposed.A modified coefficient for the ecosystem service value per unit area is proposed according to the cover degrees of biomes combined with expert consultation.Based on the developmental stage coefficient and scarcity of ecological resources,a dynamic evaluation method is proposed.The theoretical formula and simple calculation formula of the sharing benefits coefficient and benefits per unit ecological water utilization are proposed.The result shows that the benefit of unit ecological water utilization in the lower reach was greater than that in the upper reach in the Shiyang River basin.展开更多
The plant genus Metasequoia Miki,1941 and its sole living relict species Metasequoia glyptostroboides Hu et Cheng,1948 have been of special interest for both the public and scientists since 1941 when the genus was est...The plant genus Metasequoia Miki,1941 and its sole living relict species Metasequoia glyptostroboides Hu et Cheng,1948 have been of special interest for both the public and scientists since 1941 when the genus was established.Due to its unique discovery history（fossils discovered earlier than the living species） and incomparable scientific value in the research of plant evolution and its relationship with environmental and climatic changes, Metasequoia becomes arguably the most comprehensively studied higher plant in both fossil and living forms.This paper summarized recent advance in Metasequoia research by reviewing the research history of Metasequoia and the scientific value of this genus,while paid special attention to the application of new methods and techniques in the research field of Metasequoia in the recent decades.The application of biogeochemical（organic geochemistry and stable isotope） analysis as well as the new and innova ted methods of preparing large-sized cuticular membrane from leaves with originally thin and fragile cuticles further secure Metasequoia＇s super star status for the research of palaeoclimatic reconstruction.展开更多
基金Projects(2013BAB02B03,2012BAB08B00)supported by the National Science and Technology Support Program of ChinaProject(51074177)supported by the Joint Funding of National Natural Science Foundation and Shanghai Baosteel Group CorporationProjects(51274254,51322403)supported by the National Natural Science Foundation of China
文摘According to the actual conditions in Sanshandao Gold Mine, the cancelling ore pillars mining method was researched. Firstly, a series of tests for the physical and mechanical characteristics of rock mass were carried out and a quality classification system of rock mass applied in coastal metal deposit was established. Secondly, the reasonable demarcation depth of cancelling ore pillars was simulated using the finite element method, and the simulation results show that the ore pillars can be cancelled below the level of-555 m. Thirdly, a novel layer-backfill mining method of room-pillar alternation was designed to reduce the disturbance and settlement of terrain in mining area. Engineering practice shows that the new mining method enhanced the mining output and relieved rock disturbance. Furthermore, the settlement of the roof strata was small and no disaster occurred. The new mining technology effectively controlled the deformation of the terrain, indicating that the mining of the large-scale gold coastal deposit in Sanshandao Gold Mine was achieved safely, efficiently, and with a low loss rate.
基金Under the auspices of National Natural Science Foundation of China(No.31170476)Chinese Academy of Sciences/State Administration of Foreign Experts Affairs International Partnership Program for Creative Research Teams(No.KZZD-EW-TZ-07)+1 种基金Major Program of Science and Technology of Jilin Province(No.20075014)Fundamental Research Funds for the Central Universities of China(No.11GJHZ002)
文摘Large oilfields are often coincidentally located in major river deltas and wetlands,and potentially damage the structure,function and ecosystem service values of wetlands during oil exploration.In the present study,the effects of crude oil contamination during oil exploration on soil physical and chemical properties were investigated in marshes of the Momoge National Nature Reserve in Jilin Province,China.The concentrations of total petroleum hydrocarbons in the marsh soil near the oil wells are significantly higher than those in the adjacent control marsh.Soil water contents in oil-contaminated marshes are negatively correlated with soil temperature and are significantly lower than those in the control area,especially in fall.Crude oil contamination significantly increases the soil pH up to8.0,and reduces available phosphorus concentrations in the soil.The concentrations of total organic carbon are significantly different among sampling sites.Therefore,crude oil contamination could potentially alkalinize marsh soils,adversely affect soil fertility and physical properties,and cause deterioration of the marshes in the Momoge National Nature Reserve.Phyto-remediation by planting Calamagrostis angustifolia has the potential to simultaneously restore and remediate the petroleum hydrocarbon-contaminated wetlands.Crude oil contamination affects the soil physical and chemical properties,so developing an effective restoration program in the Momoge wetland is neccesary.
基金supported by the Academy of Ocean of China (No. AOCQN200812)part of the results of the scientific research project entitled ‘The Legal Issues on the Ecological Damage Caused by Marine Oil Spills
文摘The sources of marine oil spills are mainly from accidents of marine oil tankers or freighters, marine oil-drilling platforms, marine oil pipelines, marine oilfields, terrestrial pollution, oil-bearing atmosphere, and offshore oil production equipment. It is concluded upon analysis that there are two main reasons for marine oil spills: (I) The motive for huge economic benefits of oil industry owners and oil shipping agents far surpasses their sense of ecological risks. (II) Marine ecological safety has not become the main concern of national security. Oil spills are disasters because humans spare no efforts to get economic benefits from oil. The present paper draws another conclusion that marine ecological damage caused by oil spills can be roughly divided into two categories: damage to marine resource value (direct value) and damage to marine ecosystem service value (indirect value). Marine oil spills cause damage to marine biological, fishery, seawater, tourism and mineral resources to various extents, which contributes to the lower quality and value of marine resources.
文摘Petrochemicals play a vital role in the economy of any nation. The products of the industry are the building blocks in many industries as they deepen the forward and backward linkages of the petroleum sector with the rest of the economy. The industry uses a variety of hydrocarbon feedstock such as different cuts of naphtha from refinery and natural gas. One of the problems facing the industry is lack of reliable feedstock supplies. Nigeria has the potential to be a major petrochemicals producer. With proven gas reserves currently estimated at 187 tcf, not much has been accomplished with respect to the effective exploitation and utilization of this resource as most of the nation＇s natural gas production has been flared, liquefied for export or re-injected to enhance greater crude oil recovery. It has become imperative to further find ways to exploit and utilize the nation＇s natural gas reserves and translate it to the improvement of the nation＇s economy. Steam reforming of natural gas is one of the avenues for conversion of natural gas to petrochemicals. This paper, however, reviews various ways of utilizing natural gas, examines the process details of steam reforming of natural gas as a route to optimized natural gas utilization and industrialization in Nigeria. Syngas （synthesis gas） is a versatile feedstock for most petrochemicals and chemical intermediates. Thus utilizing natural gas in this way would strengthen the petrochemical industry making it possible for the country to change from raw materials to value-added products supplier, boost the economy and solve the ＂hydra-headed＂ problem of unemployment in Nigeria with its multiplier employment effect.
文摘Fish glue is the collagen from scale skin and bone of fish. It is known for value added product from fish processing and the adhesive agent for wood paper book binding etc. This work was aimed with the method to produce fish glue from fish skin through representing optimum fish type and its glue character by study on standard method for fish glue processing （using Oreochromis niloticus skin as the model）, optimum fish type and characterization of the glue from optimum fish skin. Soaking fish skin in 0.1 N NaOH for 6 h and changed it every 3 h for pretreatment before acid extraction with 0.5 M acetic acid was the optimum condition for the standard processing. Among 20 types （O. niloticus, Oreochromis sp., Nemipterus sp., Psettodes erumei, Epiephelus malabaricus, Sphyraena obstsata, Channa striata, Xenentodon cancila, Barbonymus gonionotus, Liza vaigiensis, Anabas testudineus, Chanos chanos, Micronema bleekeri, Thunnus tonggol, Rastrelliger brachysom, Epinephelus lanceolatus, Lutjanus lineolatus, Pomadasys hasta, Selar crumenophthalmus and Sardaorentalis sp.）, Chanos chanos was an appropriate type for glue production. Fat, protein, carbohydrate, moisture, pH and viscosity of Chanos chanos glue were 0.32%, 4.23%, 83.8%, 11.56%, 3.35, 4,978.33-8,180 cp, respectively. The glue was collagen type I which was composed ofal （148 kDa） and a2 （129 kDa） chain and could bind paper, wood and foam sheet.
文摘AIM:To investigate whether bile duct angulation and T-tube choledochostomy influence the recurrence of choledocholithiasis.METHODS:We conducted a retrospective study including 259 patients who underwent endoscopic sphincterotomy and cholecystectomy for choledocholithiasis between 2000 and 2007.The imaginary line was drawn along the center of the bile duct and each internal angle was measured at the two angulation sites ofthe bile duct respectively.The values of both angles were added together.We then tested our hypothesis by examining whether T-tube choledochostomy was performed and stone recurrence occurred by reviewing each subject's medical records.RESULTS:The overall recurrence rate was 9.3% (24 of 259 patients).The mean value of sums of angles in the recurrence group was 268.3°± 29.6°,while that in the non-recurrence group was 314.8°± 19.9° (P < 0.05).Recurrence rate of the T-tube group was 15.9% (17 of 107),while that of the non T-tube group was 4.6% (7 of 152) (P < 0.05).Mean value of sums of angles after T-tube drainage was 262.5°± 24.6° and that before T-tube drainage was 298.0°± 23.9° in 22 patients (P < 0.05).CONCLUSION:The bile duct angulation and T-tube choledochostomy may be risk factors of recurrence of bile duct stones.
基金Supported by National Natural Science Foundation of China (No.50879071and No.40771034)the Special Research of Public Sector of Water Resources Ministry of China (No.200801104)
文摘Among the numerous inland river basins in the arid northwest China,Shiyang River basin is known for its most serious water shortage that constrains its social and economic developments and for some of the worst ecological and environmental deterioration in China.The research on the value of water resources used for ecosystem is the basis for reasonable allocation of water resources between users of ecosystem and economic system.In this paper the concept of dynamic value for the ecosystem services is proposed.A modified coefficient for the ecosystem service value per unit area is proposed according to the cover degrees of biomes combined with expert consultation.Based on the developmental stage coefficient and scarcity of ecological resources,a dynamic evaluation method is proposed.The theoretical formula and simple calculation formula of the sharing benefits coefficient and benefits per unit ecological water utilization are proposed.The result shows that the benefit of unit ecological water utilization in the lower reach was greater than that in the upper reach in the Shiyang River basin.
文摘The plant genus Metasequoia Miki,1941 and its sole living relict species Metasequoia glyptostroboides Hu et Cheng,1948 have been of special interest for both the public and scientists since 1941 when the genus was established.Due to its unique discovery history（fossils discovered earlier than the living species） and incomparable scientific value in the research of plant evolution and its relationship with environmental and climatic changes, Metasequoia becomes arguably the most comprehensively studied higher plant in both fossil and living forms.This paper summarized recent advance in Metasequoia research by reviewing the research history of Metasequoia and the scientific value of this genus,while paid special attention to the application of new methods and techniques in the research field of Metasequoia in the recent decades.The application of biogeochemical（organic geochemistry and stable isotope） analysis as well as the new and innova ted methods of preparing large-sized cuticular membrane from leaves with originally thin and fragile cuticles further secure Metasequoia＇s super star status for the research of palaeoclimatic reconstruction.
