Freshwater mussels are a major component of the zoobenthos and they therefore play an important role in freshwater ecosystems. The community composition and the standing crop of freshwater mussels in Poyang Lake, the ...Freshwater mussels are a major component of the zoobenthos and they therefore play an important role in freshwater ecosystems. The community composition and the standing crop of freshwater mussels in Poyang Lake, the largest freshwater lake in China and one of two lakes connected to the Changjiang (Yangtze) River, were investigated from February 2008 to May 2009. Mussels were sampled in hydrologically and geographically distinct sampling areas. A total of 42 species and 13 genera were identified, of which 32 species were endemic to China. Two species, Unio douglasiae and Lamprotula caveata, dominated all sampling areas. The number of genera and species, and the number of species within each genus, differed significantly among sampling areas. Freshwater mussels were very abundant, with an overall density of 0.28±0.22 ind./m-' and biomass of 4.08±3.96 g/m^2. Significant variation observed among sampling areas and among genera was probably due to the variety of habitats among the areas sampled and to the adaptability of different freshwater mussels to environments. This study suggests that Poyang Lake and other freshwater lakes in the region are important sites of freshwater mussel biodiversity and conservation.展开更多
A new enzyme (alkaline protease 894) obtained from the marine extremophile Flavobacterium yellowsea (YS-80-122) has exhibited strong substrate-binding and catalytic activity, even at low temperature, but the character...A new enzyme (alkaline protease 894) obtained from the marine extremophile Flavobacterium yellowsea (YS-80-122) has exhibited strong substrate-binding and catalytic activity, even at low temperature, but the characteristics of the hydrolysis with this enzyme are still unclear. The pearl oyster Pinctada martensii was used in this study as the raw material to illustrate the kinetic properties of protease 894. After investigating the intrinsic relationship between the degree of hydrolysis and several factors, including initial reaction pH, temperature, substrate concentration, enzyme concentration, and hydrolysis time, the kinetics model was established. This study showed that the optimal conditions for the enzymatic hydrolysis were an initial reaction pH of 5.0, temperature of 30°C, substrate concentration of 10% (w/v), enzyme concentration of 2 500 U/g, and hydrolysis time of 160 min. The kinetic characteristics of the protease for the hydrolysis of P. martensii were obtained. The inactivation constant was found to be 15.16/min, and the average relative error between the derived kinetics model and the actual measurement was only 3.04%, which indicated a high degree of fitness. Therefore, this study provides a basis for the investigation of the concrete kinetic characteristics of the new protease, which has potential applications in the food industry.展开更多
Temperature was one of the key factors for the living environment of aquatic organisms, especially for shellfish. The effects of temperature was studied on the survival rate and the median lethal time (LT50) of the ...Temperature was one of the key factors for the living environment of aquatic organisms, especially for shellfish. The effects of temperature was studied on the survival rate and the median lethal time (LT50) of the rock scallop Crassadoma gigantea, and the effects of temperature stress on the antioxidant enzymes of rock scallop Crassadoma gigantea were studied in order to explore the effects of temperature on keeping-alive without water and antioxidant system of the rock scallop Crassadoma gigantea. The rock scallop Crassadoma gigantea (shell length (39.7± 5) mm) at different temperatures (5℃ and 15℃), humidity (moisture treatment, not moisturizing treatment) and oxygen (aerobic treatment, not aerobic treatment) in laboratory was studied by the survival analysis and the analysis of factors affecting the effects of the median lethal time (LTso) in order to investigate the effects of temperature on the survival rate and the median lethal time of the rock scallop Crassadoma gigantea. Results showed that low temperature, moisture and aerobic treatment can significantly improve the survival rate and the median lethal time of the rock scallop Crassadoma gigantea (P〈0.05). The effect of temperature on the survival rate and the median lethal time of the rock scallop Crassadoma gigantea was most significant, followed by the effect of oxygen, and that of humidity was the most weakest. Interaction between temperature and humidity, temperature and oxygen significant interaction(P〉0.05), and interaction between humidity and oxygen interaction was not significant (P〈0.05) in the interaction of three factors. It provided an important basis for the determination of the rock scallop Crassadoma gigantea in the seedling transportation time. In the article, the rock scallop Crassadoma gigantea larvae antioxidant enzymes activity was detected, including SOD activity,CAT activity ,T-A℃ activity (superoxide dismutase activity, catalase activity, total antioxidant capacity) changes through raising the temperature from the low temperature (5℃, 10℃, 15℃, 20℃, 25℃), to explore the change of the antioxidant enzymes activity under the influence of temperature on the rock scallop Crassadoma gigantea larvae. The SODactivity was significantly lower than that of the other groups (P〈0.05) at 5℃, and the CAT activity had no significant difference between groups (p=0.05), and the T - AOC level was the lowest significantly below 15℃, 25℃ (P〈0.05).The SOD and CAT activity had no significant difference in the same experimental time (P〉0.05), and the T - AOC activity temperature was significantly higher than the rest of the group (P=〈0.05) when temperature at 10℃ and 20℃. The SOD activity had no significant difference (P〉0.05)between groups at 25℃, and the CAT activity was significantly higher than 5℃ 10℃, 15℃ group (P〈0.05). The T-AOC activity was only lower than 15℃ group (P〉0.05). It indicated that the high temperature had a clear inducing effect on the CAT activity in the rock scallop Crassadoma gigantea larvae, and had a significant inhibitory effect on the T-AOC activity. The low temperature had a significant inhibitory effect on the activity of T-AOC in the tissue fluid of the scallop. The above results showed that the high and low temperature had a significant effect on the antioxidant enzymes activity of the rock scallop Crassadoma gigantea larvae.展开更多
Retention efficiencies (RE) of scallop (Chlamys farreri),oyster (Crassostrea gigas) and mussel (Mytilus edulis) in a flow-through system were measured to understand the short-term response to various particle and orga...Retention efficiencies (RE) of scallop (Chlamys farreri),oyster (Crassostrea gigas) and mussel (Mytilus edulis) in a flow-through system were measured to understand the short-term response to various particle and organic matter concentrations.By comparing the RE of C.farreri with that of C.gigas and M.edulis,we gained further knowledge on the feeding physiological characteristics of C.farreri and ascertained the possible cause of high summer mortalities of this species.The experimental feeding conditions included natural differences in the abundance and composition of suspended seston,as well as conditions in which seston abundance and composition were manipulated by adding natural silt or cultured microalgae.The results show that in natural sea water,the minimum particle size for maximal retention in M.edulis,C.gigas and C.farreri was approximately 4,6,and 8 μm,respectively;the RE of 2-μm (equivalent spherical diameter) particles was 17%,19%,and 8%,respectively;and the relative standardized RE was 58%,49%,and 18%,respectively.In C.gigas and M.edulis,the minimal particle size for maximal retention did not change with food quality (organic content).C.farreri was more sensitive to fluctuations in particle concentration and organic content.With particle concentration increase,the minimal particle size for maximal retention in scallop shifted to large particles and the RE for 2-μm particle decreased from 8% in natural seawater to 1.6%-6% in silt-enriched groups.With organic content increase,the minimal particle size for maximal retention shifted from 8 to 5 μm in natural seawater.Variation in RE of C.farreri with food conditions and the relationship between lower RE and smaller particle size may hamper C.farreri from food taking due to the decrease in the size distribution of phytoplankton in Sungo Bay.展开更多
In this paper, the results of an extensive investigation of hydrothermal pre-treatment for synthesizing belite phase from reactive mixtures (CaO/SiO2 molar ratio of 2) consisting of one waste kinds (bottom ash-BA o...In this paper, the results of an extensive investigation of hydrothermal pre-treatment for synthesizing belite phase from reactive mixtures (CaO/SiO2 molar ratio of 2) consisting of one waste kinds (bottom ash-BA or fly ash-FA) from fluidised brown coal combustion in Slovakian power plant and CaO (analytical grade reagent) addition are summarized. Changes in structure and phase composition of hydrothermally synthesized belite precursors and subsequent calcinated products were compared with those of starting mixtures. Based on XRD diffraction patterns, the formation of the new profiles corresponding to CSH phases with low degree of ordering as belite precursors after hydrothermal treatment was confirmed. Calcination of hydrotermally treated products at 900℃ led to transformation of CSH phases to wollastonite, belite and gehlenite phase. Differences in phase composition of products before and after calcination depend upon waste quality and precursor's synthesis conditions. Bottom ash isn't suitable as raw material for synthesizing belite phase because of high CaO content fixed in anhydrite form (44.1%). Coal fly ash with low CaO content in anhydrite form (4.2%) and its hydrothermal treatment in combination with subsequent heating offer opportunities for the utilization of coal fly ash as raw material for belite production.展开更多
The present study investigated the removal of inorganic arsenic from Pinctada martensii enzymatic hydrolysate through unmodified resin (D296) and Zr(IV)-loaded chelating resin (Zr-D401). By loading Zr to macropo...The present study investigated the removal of inorganic arsenic from Pinctada martensii enzymatic hydrolysate through unmodified resin (D296) and Zr(IV)-loaded chelating resin (Zr-D401). By loading Zr to macroporous chelating resin D401, the as exchange adsorption active sites are generated. This transforms D401 from a material that does not have the arsenic adsorption capacity into a material that has excellent arsenic exchange adsorption capacity. The static adsorption experiments were conducted to investigate the optimal removal condition for D296 and Zr-D401. The experimental results show that: the optimum condition for D296 is that T= 25℃, pH= 5, resin additive amount= 1 g (50 mL)-1, and contact time = 10 h, the corresponding arsenic removal rate being 65.7%, and protein loss being 2.33%; the optimum condition for Zr-D401 is that T=25 ℃, pH = 8, resin additive amount= 1 g (50 mL)-1, and contact time=10 h, the corresponding arsenic removal rate being 70.3%, and protein loss being 4.65%. These results show that both of the two resins are effective in arsenic removal for preserving useful substance. Our research provides scientific evidence and advances in the processing technology for heavy metal removal in shellfish.展开更多
This paper summarizes the selected results of an extensive investigation of application of two methods (hydrothermal and mechanochemical) assisted by calcination for synthesizing belite cement from reactive mixtures...This paper summarizes the selected results of an extensive investigation of application of two methods (hydrothermal and mechanochemical) assisted by calcination for synthesizing belite cement from reactive mixtures (CaO/SiO2 molar ratio of 2) consisting of various waste kinds from fluidized brown coal combustion in Slovakian power plant and CaO addition. Based on XRD diffraction patterns and infrared spectra ofpre-treatment products, the formation of the new profiles corresponding to CSH phases with low degree of ordering as belite precursors after hydrothermal treatment as well as metastables calcium silicates and aluminosilicates in mechanosynthesized products was confirmed. Calcination of hydrothermally treated products led to transformation of CSH phases to wollastonite (CS), belite and gehlenite phase, whereas creation oft^- and I^-C2S or wollastonite in milled reactive mixture took place. Differences in phase composition of products before and after calcination depend upon waste quality and precursor's synthesis conditions. Bottom ash isn't suitable as raw material for synthesizing belite phase because of high CaO content fixed in anhydrite form (44.1%). Coal fly ash with low CaO content in anhydrite form (4.2%) and its mechanochemical or hydrothermal treatment in combination with subsequent heating offer opportunities for the utilization of coal fly ash as raw material for belite production.展开更多
Performances of belite-rich Portland cement, or HBC (high belite cement), and the resultant concrete are introduced by comparing with that of alite based PC (Portland cement) and concrete. The comparison study of ...Performances of belite-rich Portland cement, or HBC (high belite cement), and the resultant concrete are introduced by comparing with that of alite based PC (Portland cement) and concrete. The comparison study of cement properties indicates that HBC possesses the properties of less water demand for normal consistency, better compatibility with water reducer, higher later age strength after 28-day under standard curing temperature of 20 ℃, unique strength gain under elevated curing temperatures of 38-70 ℃, lower hydration heat evolution and temperature rise, lower drying shrinkage and excellent resistance to sulphate attack. These results have been demonstrated by the comparison performance evaluation of concretes prepared by HBC and PC in terms of workability, physical mechanical properties and durability when making high performance high strength concrete and massive concrete.展开更多
Scallops of the Family Pectinidae are a valuable resource in marine industry of the world. Understanding the phylogeny of the family is important for the development of the industry. In this study, partial 16S mitocho...Scallops of the Family Pectinidae are a valuable resource in marine industry of the world. Understanding the phylogeny of the family is important for the development of the industry. In this study, partial 16S mitochondrial rDNA genes were obtained from 8 scallop species that are commonly cultured indigenous and transplanted species in China. Phylogenetic relationships of Pectinidae were analyzed based on the 8 sequences and other 5 published ones in GenBank, representing 9 genera of the family. The molecular phylogeny trees were constructed using 3 methods with software PHYLIP. The results showe that total 13 species of scallops clustered in 4 clades. Pecten maximus joins P. jacobaeus then Amusium pleuronectes in cluster, indicating close relationship of genus Amusium with Pecten in evolution. P. yes- soensis is close to Chlamys farreri and C. islandica. No enough material was available to single out genus Patinopecten as an independent monophyletic subfamily. The position of Adamussium colbecki indicates that it is far from genus Pecten but near to genus Chlamys in evolution.展开更多
A knowledge-based network for Section Yidong Bridge,Dongyang River,one tributary of Qiantang River,Zhejiang Province,China,is established in order to model water quality in areas under small data.Then,based on normal ...A knowledge-based network for Section Yidong Bridge,Dongyang River,one tributary of Qiantang River,Zhejiang Province,China,is established in order to model water quality in areas under small data.Then,based on normal transformation of variables with routine monitoring data and normal assumption of variables without routine monitoring data,a conditional linear Gaussian Bayesian network is constructed.A "two-constraint selection" procedure is proposed to estimate potential parameter values under small data.Among all potential parameter values,the ones that are most probable are selected as the "representatives".Finally,the risks of pollutant concentration exceeding national water quality standards are calculated and pollution reduction decisions for decision-making reference are proposed.The final results show that conditional linear Gaussian Bayesian network and "two-constraint selection" procedure are very useful in evaluating risks when there is limited data and can help managers to make sound decisions under small data.展开更多
A Bayesian multi-model inference framework was used to assess the changes in the occurrence of extreme hydroclimatic events in four major river basins in China (i.e., Liaohe River Basin, Yellow River Basin, Yangtze R...A Bayesian multi-model inference framework was used to assess the changes in the occurrence of extreme hydroclimatic events in four major river basins in China (i.e., Liaohe River Basin, Yellow River Basin, Yangtze River Basin, and Pearl River Basin) under RCP2.6, RCP4.5, and RCP8.5 scenarios using multiple global climate model projections from the IPCC Fifth Assessment Report. The results projected more summer days and fewer frost days in 2006-2099. The ensemble prediction shows the Pearl River Basin is projected to experience more summer days than other basins with the increasing trend of 16.3, 38.0, and 73.0 d per 100 years for RCP2.6, RCP4.5 and RCP8.5, respectively. Liaohe River Basin and Yellow River Basin are forecasted to become wetter and warmer with the co-occurrence of increases in summer days and wet days. Very heavy precipitation days (R20, daily precipitation ≥20 mm) are projected to increase in all basins. The R20 in the Yangtze River Basin are projected to have the highest change rate in 2006-2099 of 1.8, 2.5, and 3.8 d per 100 years for RCP2.6, RCP4.5 and RCP8.5, respectively.展开更多
基金Supported by the National Natural Science Foundation of China(No. 30860045)
文摘Freshwater mussels are a major component of the zoobenthos and they therefore play an important role in freshwater ecosystems. The community composition and the standing crop of freshwater mussels in Poyang Lake, the largest freshwater lake in China and one of two lakes connected to the Changjiang (Yangtze) River, were investigated from February 2008 to May 2009. Mussels were sampled in hydrologically and geographically distinct sampling areas. A total of 42 species and 13 genera were identified, of which 32 species were endemic to China. Two species, Unio douglasiae and Lamprotula caveata, dominated all sampling areas. The number of genera and species, and the number of species within each genus, differed significantly among sampling areas. Freshwater mussels were very abundant, with an overall density of 0.28±0.22 ind./m-' and biomass of 4.08±3.96 g/m^2. Significant variation observed among sampling areas and among genera was probably due to the variety of habitats among the areas sampled and to the adaptability of different freshwater mussels to environments. This study suggests that Poyang Lake and other freshwater lakes in the region are important sites of freshwater mussel biodiversity and conservation.
基金Supported by the Comprehensive Strategic Cooperation Programs between Guangdong Province and Chinese Academy of Sciences(No.2011A090100008)the Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX2-EW-Q214)
文摘A new enzyme (alkaline protease 894) obtained from the marine extremophile Flavobacterium yellowsea (YS-80-122) has exhibited strong substrate-binding and catalytic activity, even at low temperature, but the characteristics of the hydrolysis with this enzyme are still unclear. The pearl oyster Pinctada martensii was used in this study as the raw material to illustrate the kinetic properties of protease 894. After investigating the intrinsic relationship between the degree of hydrolysis and several factors, including initial reaction pH, temperature, substrate concentration, enzyme concentration, and hydrolysis time, the kinetics model was established. This study showed that the optimal conditions for the enzymatic hydrolysis were an initial reaction pH of 5.0, temperature of 30°C, substrate concentration of 10% (w/v), enzyme concentration of 2 500 U/g, and hydrolysis time of 160 min. The kinetic characteristics of the protease for the hydrolysis of P. martensii were obtained. The inactivation constant was found to be 15.16/min, and the average relative error between the derived kinetics model and the actual measurement was only 3.04%, which indicated a high degree of fitness. Therefore, this study provides a basis for the investigation of the concrete kinetic characteristics of the new protease, which has potential applications in the food industry.
文摘Temperature was one of the key factors for the living environment of aquatic organisms, especially for shellfish. The effects of temperature was studied on the survival rate and the median lethal time (LT50) of the rock scallop Crassadoma gigantea, and the effects of temperature stress on the antioxidant enzymes of rock scallop Crassadoma gigantea were studied in order to explore the effects of temperature on keeping-alive without water and antioxidant system of the rock scallop Crassadoma gigantea. The rock scallop Crassadoma gigantea (shell length (39.7± 5) mm) at different temperatures (5℃ and 15℃), humidity (moisture treatment, not moisturizing treatment) and oxygen (aerobic treatment, not aerobic treatment) in laboratory was studied by the survival analysis and the analysis of factors affecting the effects of the median lethal time (LTso) in order to investigate the effects of temperature on the survival rate and the median lethal time of the rock scallop Crassadoma gigantea. Results showed that low temperature, moisture and aerobic treatment can significantly improve the survival rate and the median lethal time of the rock scallop Crassadoma gigantea (P〈0.05). The effect of temperature on the survival rate and the median lethal time of the rock scallop Crassadoma gigantea was most significant, followed by the effect of oxygen, and that of humidity was the most weakest. Interaction between temperature and humidity, temperature and oxygen significant interaction(P〉0.05), and interaction between humidity and oxygen interaction was not significant (P〈0.05) in the interaction of three factors. It provided an important basis for the determination of the rock scallop Crassadoma gigantea in the seedling transportation time. In the article, the rock scallop Crassadoma gigantea larvae antioxidant enzymes activity was detected, including SOD activity,CAT activity ,T-A℃ activity (superoxide dismutase activity, catalase activity, total antioxidant capacity) changes through raising the temperature from the low temperature (5℃, 10℃, 15℃, 20℃, 25℃), to explore the change of the antioxidant enzymes activity under the influence of temperature on the rock scallop Crassadoma gigantea larvae. The SODactivity was significantly lower than that of the other groups (P〈0.05) at 5℃, and the CAT activity had no significant difference between groups (p=0.05), and the T - AOC level was the lowest significantly below 15℃, 25℃ (P〈0.05).The SOD and CAT activity had no significant difference in the same experimental time (P〉0.05), and the T - AOC activity temperature was significantly higher than the rest of the group (P=〈0.05) when temperature at 10℃ and 20℃. The SOD activity had no significant difference (P〉0.05)between groups at 25℃, and the CAT activity was significantly higher than 5℃ 10℃, 15℃ group (P〈0.05). The T-AOC activity was only lower than 15℃ group (P〉0.05). It indicated that the high temperature had a clear inducing effect on the CAT activity in the rock scallop Crassadoma gigantea larvae, and had a significant inhibitory effect on the T-AOC activity. The low temperature had a significant inhibitory effect on the activity of T-AOC in the tissue fluid of the scallop. The above results showed that the high and low temperature had a significant effect on the antioxidant enzymes activity of the rock scallop Crassadoma gigantea larvae.
基金Supported by the National Natural Science Foundation of China (No. 40676093)European Community INCO-DC Project ERBIC18CT980291+2 种基金National Basic Research Program of China (973 Program) (2006CB400608)National High Technology Research and Development Program of China (863 Program) (No. 2006AA100307)National High Technology Research and Development Program of China (863 Program)(No.2006BAD09A09)
文摘Retention efficiencies (RE) of scallop (Chlamys farreri),oyster (Crassostrea gigas) and mussel (Mytilus edulis) in a flow-through system were measured to understand the short-term response to various particle and organic matter concentrations.By comparing the RE of C.farreri with that of C.gigas and M.edulis,we gained further knowledge on the feeding physiological characteristics of C.farreri and ascertained the possible cause of high summer mortalities of this species.The experimental feeding conditions included natural differences in the abundance and composition of suspended seston,as well as conditions in which seston abundance and composition were manipulated by adding natural silt or cultured microalgae.The results show that in natural sea water,the minimum particle size for maximal retention in M.edulis,C.gigas and C.farreri was approximately 4,6,and 8 μm,respectively;the RE of 2-μm (equivalent spherical diameter) particles was 17%,19%,and 8%,respectively;and the relative standardized RE was 58%,49%,and 18%,respectively.In C.gigas and M.edulis,the minimal particle size for maximal retention did not change with food quality (organic content).C.farreri was more sensitive to fluctuations in particle concentration and organic content.With particle concentration increase,the minimal particle size for maximal retention in scallop shifted to large particles and the RE for 2-μm particle decreased from 8% in natural seawater to 1.6%-6% in silt-enriched groups.With organic content increase,the minimal particle size for maximal retention shifted from 8 to 5 μm in natural seawater.Variation in RE of C.farreri with food conditions and the relationship between lower RE and smaller particle size may hamper C.farreri from food taking due to the decrease in the size distribution of phytoplankton in Sungo Bay.
文摘In this paper, the results of an extensive investigation of hydrothermal pre-treatment for synthesizing belite phase from reactive mixtures (CaO/SiO2 molar ratio of 2) consisting of one waste kinds (bottom ash-BA or fly ash-FA) from fluidised brown coal combustion in Slovakian power plant and CaO (analytical grade reagent) addition are summarized. Changes in structure and phase composition of hydrothermally synthesized belite precursors and subsequent calcinated products were compared with those of starting mixtures. Based on XRD diffraction patterns, the formation of the new profiles corresponding to CSH phases with low degree of ordering as belite precursors after hydrothermal treatment was confirmed. Calcination of hydrotermally treated products at 900℃ led to transformation of CSH phases to wollastonite, belite and gehlenite phase. Differences in phase composition of products before and after calcination depend upon waste quality and precursor's synthesis conditions. Bottom ash isn't suitable as raw material for synthesizing belite phase because of high CaO content fixed in anhydrite form (44.1%). Coal fly ash with low CaO content in anhydrite form (4.2%) and its hydrothermal treatment in combination with subsequent heating offer opportunities for the utilization of coal fly ash as raw material for belite production.
基金supported by National Key Technologies R&D Program of China(2008 BAD94B08)
文摘The present study investigated the removal of inorganic arsenic from Pinctada martensii enzymatic hydrolysate through unmodified resin (D296) and Zr(IV)-loaded chelating resin (Zr-D401). By loading Zr to macroporous chelating resin D401, the as exchange adsorption active sites are generated. This transforms D401 from a material that does not have the arsenic adsorption capacity into a material that has excellent arsenic exchange adsorption capacity. The static adsorption experiments were conducted to investigate the optimal removal condition for D296 and Zr-D401. The experimental results show that: the optimum condition for D296 is that T= 25℃, pH= 5, resin additive amount= 1 g (50 mL)-1, and contact time = 10 h, the corresponding arsenic removal rate being 65.7%, and protein loss being 2.33%; the optimum condition for Zr-D401 is that T=25 ℃, pH = 8, resin additive amount= 1 g (50 mL)-1, and contact time=10 h, the corresponding arsenic removal rate being 70.3%, and protein loss being 4.65%. These results show that both of the two resins are effective in arsenic removal for preserving useful substance. Our research provides scientific evidence and advances in the processing technology for heavy metal removal in shellfish.
文摘This paper summarizes the selected results of an extensive investigation of application of two methods (hydrothermal and mechanochemical) assisted by calcination for synthesizing belite cement from reactive mixtures (CaO/SiO2 molar ratio of 2) consisting of various waste kinds from fluidized brown coal combustion in Slovakian power plant and CaO addition. Based on XRD diffraction patterns and infrared spectra ofpre-treatment products, the formation of the new profiles corresponding to CSH phases with low degree of ordering as belite precursors after hydrothermal treatment as well as metastables calcium silicates and aluminosilicates in mechanosynthesized products was confirmed. Calcination of hydrothermally treated products led to transformation of CSH phases to wollastonite (CS), belite and gehlenite phase, whereas creation oft^- and I^-C2S or wollastonite in milled reactive mixture took place. Differences in phase composition of products before and after calcination depend upon waste quality and precursor's synthesis conditions. Bottom ash isn't suitable as raw material for synthesizing belite phase because of high CaO content fixed in anhydrite form (44.1%). Coal fly ash with low CaO content in anhydrite form (4.2%) and its mechanochemical or hydrothermal treatment in combination with subsequent heating offer opportunities for the utilization of coal fly ash as raw material for belite production.
文摘Performances of belite-rich Portland cement, or HBC (high belite cement), and the resultant concrete are introduced by comparing with that of alite based PC (Portland cement) and concrete. The comparison study of cement properties indicates that HBC possesses the properties of less water demand for normal consistency, better compatibility with water reducer, higher later age strength after 28-day under standard curing temperature of 20 ℃, unique strength gain under elevated curing temperatures of 38-70 ℃, lower hydration heat evolution and temperature rise, lower drying shrinkage and excellent resistance to sulphate attack. These results have been demonstrated by the comparison performance evaluation of concretes prepared by HBC and PC in terms of workability, physical mechanical properties and durability when making high performance high strength concrete and massive concrete.
基金Supported by National S&T Support Program (2006BAD09A02)NSFC (39700017)
文摘Scallops of the Family Pectinidae are a valuable resource in marine industry of the world. Understanding the phylogeny of the family is important for the development of the industry. In this study, partial 16S mitochondrial rDNA genes were obtained from 8 scallop species that are commonly cultured indigenous and transplanted species in China. Phylogenetic relationships of Pectinidae were analyzed based on the 8 sequences and other 5 published ones in GenBank, representing 9 genera of the family. The molecular phylogeny trees were constructed using 3 methods with software PHYLIP. The results showe that total 13 species of scallops clustered in 4 clades. Pecten maximus joins P. jacobaeus then Amusium pleuronectes in cluster, indicating close relationship of genus Amusium with Pecten in evolution. P. yes- soensis is close to Chlamys farreri and C. islandica. No enough material was available to single out genus Patinopecten as an independent monophyletic subfamily. The position of Adamussium colbecki indicates that it is far from genus Pecten but near to genus Chlamys in evolution.
基金Project(50809058)supported by the National Natural Science Foundation of China
文摘A knowledge-based network for Section Yidong Bridge,Dongyang River,one tributary of Qiantang River,Zhejiang Province,China,is established in order to model water quality in areas under small data.Then,based on normal transformation of variables with routine monitoring data and normal assumption of variables without routine monitoring data,a conditional linear Gaussian Bayesian network is constructed.A "two-constraint selection" procedure is proposed to estimate potential parameter values under small data.Among all potential parameter values,the ones that are most probable are selected as the "representatives".Finally,the risks of pollutant concentration exceeding national water quality standards are calculated and pollution reduction decisions for decision-making reference are proposed.The final results show that conditional linear Gaussian Bayesian network and "two-constraint selection" procedure are very useful in evaluating risks when there is limited data and can help managers to make sound decisions under small data.
基金Acknowledgments Funding for this research was provided by the National Key Basic Special Foundation Project of China (2010CB428400), and the National Natural Science Foundation of China (41375139). We are grateful to the Program for Climate Model Diagnosis and Intercomparison for collecting and archiving the model data.
文摘A Bayesian multi-model inference framework was used to assess the changes in the occurrence of extreme hydroclimatic events in four major river basins in China (i.e., Liaohe River Basin, Yellow River Basin, Yangtze River Basin, and Pearl River Basin) under RCP2.6, RCP4.5, and RCP8.5 scenarios using multiple global climate model projections from the IPCC Fifth Assessment Report. The results projected more summer days and fewer frost days in 2006-2099. The ensemble prediction shows the Pearl River Basin is projected to experience more summer days than other basins with the increasing trend of 16.3, 38.0, and 73.0 d per 100 years for RCP2.6, RCP4.5 and RCP8.5, respectively. Liaohe River Basin and Yellow River Basin are forecasted to become wetter and warmer with the co-occurrence of increases in summer days and wet days. Very heavy precipitation days (R20, daily precipitation ≥20 mm) are projected to increase in all basins. The R20 in the Yangtze River Basin are projected to have the highest change rate in 2006-2099 of 1.8, 2.5, and 3.8 d per 100 years for RCP2.6, RCP4.5 and RCP8.5, respectively.