In this paper, we explore the refined semilattice of left C-wrpp semigroups, and show that a left C-wrpp semigroup S is a refined semilattice of left-R cancellative stripes if and only if it is a spined product of a C...In this paper, we explore the refined semilattice of left C-wrpp semigroups, and show that a left C-wrpp semigroup S is a refined semilattice of left-R cancellative stripes if and only if it is a spined product of a C-wrpp component and a left regular band. It is a generalization of the refined semilattice decomposition of left C-rpp semigroups.展开更多
对铬冶炼产物进行了回收金属铬的选矿试验研究。试验结果表明,金属铬块适宜的分选工艺为"煤油反浮选-强磁选"联合工艺流程。在磨矿细度为-0.074 mm 8.43%时,以煤油为捕收剂,松醇油为起泡剂,经一次粗选一次精选反浮选脱炭,一...对铬冶炼产物进行了回收金属铬的选矿试验研究。试验结果表明,金属铬块适宜的分选工艺为"煤油反浮选-强磁选"联合工艺流程。在磨矿细度为-0.074 mm 8.43%时,以煤油为捕收剂,松醇油为起泡剂,经一次粗选一次精选反浮选脱炭,一次强磁选脱除三氧化二铬,最终可获得综合金属铬精矿的金属铬品位为97.16%,回收率为62.29%,满足高质量金属铬精矿的品质要求。展开更多
The study aims at investigating chemical speciation,bioavailability and risk assessment of some selected metals in soils around refined petroleum depot using the concentrations of the metals as variables to ascertain ...The study aims at investigating chemical speciation,bioavailability and risk assessment of some selected metals in soils around refined petroleum depot using the concentrations of the metals as variables to ascertain the impacts of the activities within the petroleum depot.Surface-soils(0e15 cm)were collected from within the premises of Pipelines and Product Marketing Company,Ibadan,Nigeria,while control samples were collected at 200 m away from the study location.Electrical conductivity and pH were measured using a calibrated dual purpose meter,while elemental analysis was done using Atomic absorption spectroscopy analytical technique.The results showed that the soils exhibited low ecological risk;minor enrichment for Mn,moderately severe enrichment for Ni and Co,severe enrichment for Cr and extremely severe enrichment for Pb,Zn and Cd.There was low contamination factor for Pb,Ni,Mn,Cr,Co,and Fe and moderate contamination by Zn and Cd.Geo-accumulation index results indicated unpolluted with Ni,Mn,Cr,Co,and Fe,unpolluted to moderately polluted with Pb and Zn and moderately to strongly polluted with Cd.Inter-element clustering results indicated chemical affinity and/or similar genetic origin among the elements.Speciation analysis suggested that Fe,Co,Cr,Cd,and Ni occurred in the residual fraction;Pb,and Zn in the carbonate fraction,while Mn have its highest percentage in the Fe eMn oxides fraction.Percentage mobility and bioavailability showed that most of the metals are immobile and non-bioavailable.Study concluded that the oil-impacted soils were contaminated with most of the metals,but with low ecological risk.展开更多
The author used two common methods in this industry, i. e. the ＂Consumption Coefficient Method＂ and the ＂Elasticity Coefficient Trend Method＂, to forecast the refined oil product demand in 2010. Through analyzing ...The author used two common methods in this industry, i. e. the ＂Consumption Coefficient Method＂ and the ＂Elasticity Coefficient Trend Method＂, to forecast the refined oil product demand in 2010. Through analyzing and comparing the two forecast results, it is projected that the demand for finished product oils in 2010 will be in the range of 220 to 240 million tons a year. In addition, out of concern about the total oil products consumption to exceed 600 million tons/year in 2020, the author puts forward suggestions and measures aimed at conservation of oil products and application of alternative fuels.展开更多
基金the Natural Science Foundation of Huizhou University （No. C207.0202）.
文摘In this paper, we explore the refined semilattice of left C-wrpp semigroups, and show that a left C-wrpp semigroup S is a refined semilattice of left-R cancellative stripes if and only if it is a spined product of a C-wrpp component and a left regular band. It is a generalization of the refined semilattice decomposition of left C-rpp semigroups.
文摘对铬冶炼产物进行了回收金属铬的选矿试验研究。试验结果表明,金属铬块适宜的分选工艺为"煤油反浮选-强磁选"联合工艺流程。在磨矿细度为-0.074 mm 8.43%时,以煤油为捕收剂,松醇油为起泡剂,经一次粗选一次精选反浮选脱炭,一次强磁选脱除三氧化二铬,最终可获得综合金属铬精矿的金属铬品位为97.16%,回收率为62.29%,满足高质量金属铬精矿的品质要求。
文摘The study aims at investigating chemical speciation,bioavailability and risk assessment of some selected metals in soils around refined petroleum depot using the concentrations of the metals as variables to ascertain the impacts of the activities within the petroleum depot.Surface-soils(0e15 cm)were collected from within the premises of Pipelines and Product Marketing Company,Ibadan,Nigeria,while control samples were collected at 200 m away from the study location.Electrical conductivity and pH were measured using a calibrated dual purpose meter,while elemental analysis was done using Atomic absorption spectroscopy analytical technique.The results showed that the soils exhibited low ecological risk;minor enrichment for Mn,moderately severe enrichment for Ni and Co,severe enrichment for Cr and extremely severe enrichment for Pb,Zn and Cd.There was low contamination factor for Pb,Ni,Mn,Cr,Co,and Fe and moderate contamination by Zn and Cd.Geo-accumulation index results indicated unpolluted with Ni,Mn,Cr,Co,and Fe,unpolluted to moderately polluted with Pb and Zn and moderately to strongly polluted with Cd.Inter-element clustering results indicated chemical affinity and/or similar genetic origin among the elements.Speciation analysis suggested that Fe,Co,Cr,Cd,and Ni occurred in the residual fraction;Pb,and Zn in the carbonate fraction,while Mn have its highest percentage in the Fe eMn oxides fraction.Percentage mobility and bioavailability showed that most of the metals are immobile and non-bioavailable.Study concluded that the oil-impacted soils were contaminated with most of the metals,but with low ecological risk.
文摘The author used two common methods in this industry, i. e. the ＂Consumption Coefficient Method＂ and the ＂Elasticity Coefficient Trend Method＂, to forecast the refined oil product demand in 2010. Through analyzing and comparing the two forecast results, it is projected that the demand for finished product oils in 2010 will be in the range of 220 to 240 million tons a year. In addition, out of concern about the total oil products consumption to exceed 600 million tons/year in 2020, the author puts forward suggestions and measures aimed at conservation of oil products and application of alternative fuels.
