To obtain carbon dioxide （CO2） flux between water-air interface of Taihu lake, monthly water samplers at 14 sites and the local meteorological data of the lake were collected and analyzed in 1998. Carbon dioxide par...To obtain carbon dioxide （CO2） flux between water-air interface of Taihu lake, monthly water samplers at 14 sites and the local meteorological data of the lake were collected and analyzed in 1998. Carbon dioxide partial pressures （pCO2） at air-water interface in the lake were calculated using alkalinity, pH, ionic strength, active coefficient, and water temperature. The carbon fluxes at different sublakes and areas were estimated by concentration gradient between water and air in consideration of Schmidt numbers of 600 and daily mean windspeed at 10 m above water surface. The results indicated that the mean values of pCO2 in Wuli Lake,Meiliang Bay, hydrophyte area, west littoral zone, riverine mouths, and the open lake areas were 1 807.8±1 071.4（mean±standard deviation）μatm （latm=1.013 25×10^5pa）, 416.3±217.0μatm, 576.5±758.8μatm, 304.2±9.43.5μatm, 1 933.6±1 144.7 μatm, and 448.5±202.6μatm, respectively. Maximum and minimum pCO2 values were found in the hypertrophic （4 053.7μatm） and the eutrophic （3.2 μatm） areas. The riverine mouth areas have the maximum fluxes （82.0±62.8 mmol/m^2a）. But there was no significant difference between eutrophic and mesotrophic areas in pCO2 and the flux of CO2. The hydrophyte area, however, has the minimum （--0.58±12.9mmol/m^2a）. In respect to CO2 equilibrium, input of the rivers will obviously influence inorganic carbon distribution in the riverine estuary. For example, the annual mean CO2 flux in Zhihugang River estuary was 19 times of that in Meiliang Bay, although the former is only a part of the latter. The sites in the body of the lake show a clear seasonal cycle with pCO2 higher than atmospheric equilibrium in winter, and much lower than atmospheric in summer due to CO2 consumption by photosynthesis. The CO2 amount of the net annual evasion that enters the atmosphere is 28.42×10^4 t/a, of which those from the west littoral zone and the open lake account for 53.8% and 36.7%, respectively.展开更多
In order to obtain solubility data of propylene in 2-butanol+water solutions, gas-liquid equilibrium(GLE) experiment was carried out at 303.15--333.15 K, 0.3-1.2 MPa with static equilibrium still. Original mass ratios...In order to obtain solubility data of propylene in 2-butanol+water solutions, gas-liquid equilibrium(GLE) experiment was carried out at 303.15--333.15 K, 0.3-1.2 MPa with static equilibrium still. Original mass ratios of 2-butanol to water are 1:0，9:1,8:2 and 7:3, respectively. The equilibrium data are correlated with an empirical correlation. The average relative deviation (ARD) between experimental and calculated values is 2.15%,and the maximum relative deviation (MRD) is less than 5%.展开更多
By using the equipment designed and developed by ourselves, experiment of investigating the influence of dissolution on some geo-chemical parameters (such as δ13C,δD,and iC4/nC4 in water-dissolved gas (WDG) during m...By using the equipment designed and developed by ourselves, experiment of investigating the influence of dissolution on some geo-chemical parameters (such as δ13C,δD,and iC4/nC4 in water-dissolved gas (WDG) during migration) was performed. The result shows that, with the increase of distance, 1) the relative abundance of non-hydrocarbon (CO2) and hydrocarbon (CH4) increase while the relative abundance of hydrocarbon (C2+) decreases (the relative abundance of hydrocarbon (C5+) can be basically negligible); 2) the relative abundance of benzene and methylbenzene increase in the initial time and then decrease. The carbon and hydrogen isotopes of methane vary slightly, which can be regarded as indicators of gas dissolved in water formation.展开更多
In order to obtain the solubility data of propylene in 2-propanol-water solutions, gas-liquid equilibrium (GLE) experiments were carried out at 303.15-333.15 K, 0.27-0.98 MPa in a static equilibrium still. The origina...In order to obtain the solubility data of propylene in 2-propanol-water solutions, gas-liquid equilibrium (GLE) experiments were carried out at 303.15-333.15 K, 0.27-0.98 MPa in a static equilibrium still. The original mass ratio of 2-propanol to water was 9∶1,8∶2,7∶3,1∶0, respectively. The equilibrium data were correlated with an empirical model and the regression of model parameters was completed by Gauss-Newton nonlinear least square (NLS). The average relative deviation (ARD) between the experimental and calculated value is 1.570 0, and the maximum relative deviation (MRD) is 4.820 0. In addition, a simple approach that correlated the model parameters with the system composition was also provided.展开更多
This experiment researches textile wastewater, adopts a BAF process that has developed quickly in recent years, and makes use of dissolved air flotation as a pretreatment process that can effectively make up for BAF’...This experiment researches textile wastewater, adopts a BAF process that has developed quickly in recent years, and makes use of dissolved air flotation as a pretreatment process that can effectively make up for BAF’s lack of removing Chromaticity color. Performance effect, influencing factor, control condition have been reviewed and parameters of correlation have been analyzed in this experiment. The experiment and actual performance results indicate that this process is an effective way to remove the COD, suspended solid and colority with the value of 100 mg/L, 50 mg/L and 70 multiple respectively. The effluent meets the requirement of the standards of national sewage discharge. This process features a simple schematic, small location, continuous, reliable performance, strong shock and loading resistance and easy operation. Experimental data can provide scientific evidence and technical support for engineering practice of this process.展开更多
The effect of total dissolved gas （TDG） supersaturation on fish living downstream of dams is one of the main ecological risks of high dam construction. A strategy for mitigating the negative effects is needed urgent...The effect of total dissolved gas （TDG） supersaturation on fish living downstream of dams is one of the main ecological risks of high dam construction. A strategy for mitigating the negative effects is needed urgently since many high dams are under construction in the upper reaches of the Yangtze River in China. Experiments on the hatching process of David＇s schizothoracin were carried out and the results show that the hatching rate decreased with increasing TDG levels, and that most eggs hatched within a very short time in the higher TDG saturation groups. By using a stereomicroscope, damages to the head, yolk sac, body, anus, etc. were found in larvae which hatched in TDG supersaturated water. Results show that the lesion rate increased with increasing TDG levels. Furthermore, 7-d-old David＇s schizothoracin were exposed to TDG supersaturated water levels of 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, and 140% for testing their tolerance to TDG supersaturation. We found that the median lethal concentrations （LC50） for 13, 14, 20, 35, 52, 73, and 96 h exposure were 138%, 138%, 134%, 130%, 129%, 128%, and 126%, respectively. The median lethal times （LTs0） were 7.49, 11.04, 19.25, and 35.38 h for exposure to water with TDG levels of 145%, 140%, 135%, and 130%, respectively.展开更多
Affected by structural uplift, the Ordovician carbonate rockbed in the Tarim Basin, China, was exposed to dissolution and reformation of atmospheric precipitation many times, and formed a large quantity of karst caves...Affected by structural uplift, the Ordovician carbonate rockbed in the Tarim Basin, China, was exposed to dissolution and reformation of atmospheric precipitation many times, and formed a large quantity of karst caves serving as hydrocarbon reser- voir. However, drilling in Tahe area showed that many large karst caves, small pores and fractures are filled by calcite, result- ing in decrease in their reservoir ability. Calcite filled in the karst caves has very light oxygen isotopic composition and STSr/S（＇Sr ratio. Its c^OpDB ranges from -21.2%o to 13.3%o with the average of -16.3%e and its 87Sr/86Nr ratio ranges from 0.709561 to 0.710070 with the average of 0.709843. The isotope composition showed that calcite is related to atmospheric precipitation. Theoretic analyses indicated that the dissolving and filling actions of the precipitation on carbonate rocks are controlled by both thermodynamic and kinetic mechanisms. Among them, the thermodynamic factor determines that the pre- cipitation during its flow from the earth surface downward plays important roles on carbonate rocks from dissolution to satura- tion, further sedimentation, and finally filling. In other words, the depth of the karstification development is not unrestricted, but limited by the precipitation beneath the earth surface. On the other hand, the kinetic factor controls the intensity, depth, and breadth of the karstification development, that is, the karstification is also affected by topographic, geomorphologic, climatic factors, the degree of fracture or fault, etc. Therefore, subject to their joint effects, the karstification of the precipitation on the Ordovician carbonate rocks occurs only within a certain depth （most about 200 m） under the unconformity surface, deeper than which carbonate minerals begin to sedimentate and fill the karst caves that were formed previously.展开更多
One of the possible negative environmental effects of hydropower stations is the supersaturation of total dissolved gas (TDG) downstream of high-dams,which can lead to gas bubble disease or even death of fish. By taki...One of the possible negative environmental effects of hydropower stations is the supersaturation of total dissolved gas (TDG) downstream of high-dams,which can lead to gas bubble disease or even death of fish. By taking the TDG as the main study object,the paper launched the TDG field observations on Zipingpu,Three Gorges,Ertan,Manwan,Dachaoshan,Gongzui and Ertan dams in China. The factors affecting TDG generation and dissipation were explored. Energy dissipation structures,spill rates and operation patterns were the main factors causing TDG supersaturation. TDG saturations are essentially the same in the hydro-electric tail water and in the upper reaches,so hydro-electric tail water can be less TDG supersaturated through mixing downstream. The main factors affecting the dissipation process of the supersaturated TDG were tributary convergence,water depth and turbulence. TDG supersaturation was unevenly distributed in both the vertical and transverse directions. This study is important because it adds to the accumulating experience of TDG field observations of dam projects in China,and because it objectively and impartially evaluates the impacts of supersaturated TDG. The study also provides field data and references for future studies of TDG supersaturation caused by high-dams.展开更多
基金This research was supported by the Knowledge Innovation Project of Chinese Academy of Sciences (KZCX1-SW-01-15) and (KZCX1- SW-12)
文摘To obtain carbon dioxide （CO2） flux between water-air interface of Taihu lake, monthly water samplers at 14 sites and the local meteorological data of the lake were collected and analyzed in 1998. Carbon dioxide partial pressures （pCO2） at air-water interface in the lake were calculated using alkalinity, pH, ionic strength, active coefficient, and water temperature. The carbon fluxes at different sublakes and areas were estimated by concentration gradient between water and air in consideration of Schmidt numbers of 600 and daily mean windspeed at 10 m above water surface. The results indicated that the mean values of pCO2 in Wuli Lake,Meiliang Bay, hydrophyte area, west littoral zone, riverine mouths, and the open lake areas were 1 807.8±1 071.4（mean±standard deviation）μatm （latm=1.013 25×10^5pa）, 416.3±217.0μatm, 576.5±758.8μatm, 304.2±9.43.5μatm, 1 933.6±1 144.7 μatm, and 448.5±202.6μatm, respectively. Maximum and minimum pCO2 values were found in the hypertrophic （4 053.7μatm） and the eutrophic （3.2 μatm） areas. The riverine mouth areas have the maximum fluxes （82.0±62.8 mmol/m^2a）. But there was no significant difference between eutrophic and mesotrophic areas in pCO2 and the flux of CO2. The hydrophyte area, however, has the minimum （--0.58±12.9mmol/m^2a）. In respect to CO2 equilibrium, input of the rivers will obviously influence inorganic carbon distribution in the riverine estuary. For example, the annual mean CO2 flux in Zhihugang River estuary was 19 times of that in Meiliang Bay, although the former is only a part of the latter. The sites in the body of the lake show a clear seasonal cycle with pCO2 higher than atmospheric equilibrium in winter, and much lower than atmospheric in summer due to CO2 consumption by photosynthesis. The CO2 amount of the net annual evasion that enters the atmosphere is 28.42×10^4 t/a, of which those from the west littoral zone and the open lake account for 53.8% and 36.7%, respectively.
基金Supported by the National Fundamental Research Development Program of China (G2000048005) and the State Key Laboratories of Chemical Engineering, China (0047).
文摘In order to obtain solubility data of propylene in 2-butanol+water solutions, gas-liquid equilibrium(GLE) experiment was carried out at 303.15--333.15 K, 0.3-1.2 MPa with static equilibrium still. Original mass ratios of 2-butanol to water are 1:0，9:1,8:2 and 7:3, respectively. The equilibrium data are correlated with an empirical correlation. The average relative deviation (ARD) between experimental and calculated values is 2.15%,and the maximum relative deviation (MRD) is less than 5%.
文摘By using the equipment designed and developed by ourselves, experiment of investigating the influence of dissolution on some geo-chemical parameters (such as δ13C,δD,and iC4/nC4 in water-dissolved gas (WDG) during migration) was performed. The result shows that, with the increase of distance, 1) the relative abundance of non-hydrocarbon (CO2) and hydrocarbon (CH4) increase while the relative abundance of hydrocarbon (C2+) decreases (the relative abundance of hydrocarbon (C5+) can be basically negligible); 2) the relative abundance of benzene and methylbenzene increase in the initial time and then decrease. The carbon and hydrogen isotopes of methane vary slightly, which can be regarded as indicators of gas dissolved in water formation.
文摘In order to obtain the solubility data of propylene in 2-propanol-water solutions, gas-liquid equilibrium (GLE) experiments were carried out at 303.15-333.15 K, 0.27-0.98 MPa in a static equilibrium still. The original mass ratio of 2-propanol to water was 9∶1,8∶2,7∶3,1∶0, respectively. The equilibrium data were correlated with an empirical model and the regression of model parameters was completed by Gauss-Newton nonlinear least square (NLS). The average relative deviation (ARD) between the experimental and calculated value is 1.570 0, and the maximum relative deviation (MRD) is 4.820 0. In addition, a simple approach that correlated the model parameters with the system composition was also provided.
文摘This experiment researches textile wastewater, adopts a BAF process that has developed quickly in recent years, and makes use of dissolved air flotation as a pretreatment process that can effectively make up for BAF’s lack of removing Chromaticity color. Performance effect, influencing factor, control condition have been reviewed and parameters of correlation have been analyzed in this experiment. The experiment and actual performance results indicate that this process is an effective way to remove the COD, suspended solid and colority with the value of 100 mg/L, 50 mg/L and 70 multiple respectively. The effluent meets the requirement of the standards of national sewage discharge. This process features a simple schematic, small location, continuous, reliable performance, strong shock and loading resistance and easy operation. Experimental data can provide scientific evidence and technical support for engineering practice of this process.
基金Project (No. 50979063) supported by the National Natural Science Foundation of China
文摘The effect of total dissolved gas （TDG） supersaturation on fish living downstream of dams is one of the main ecological risks of high dam construction. A strategy for mitigating the negative effects is needed urgently since many high dams are under construction in the upper reaches of the Yangtze River in China. Experiments on the hatching process of David＇s schizothoracin were carried out and the results show that the hatching rate decreased with increasing TDG levels, and that most eggs hatched within a very short time in the higher TDG saturation groups. By using a stereomicroscope, damages to the head, yolk sac, body, anus, etc. were found in larvae which hatched in TDG supersaturated water. Results show that the lesion rate increased with increasing TDG levels. Furthermore, 7-d-old David＇s schizothoracin were exposed to TDG supersaturated water levels of 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, and 140% for testing their tolerance to TDG supersaturation. We found that the median lethal concentrations （LC50） for 13, 14, 20, 35, 52, 73, and 96 h exposure were 138%, 138%, 134%, 130%, 129%, 128%, and 126%, respectively. The median lethal times （LTs0） were 7.49, 11.04, 19.25, and 35.38 h for exposure to water with TDG levels of 145%, 140%, 135%, and 130%, respectively.
基金sponsored by the National Basic Research Program of China(Grant No.2012CB214802)National Natural Science Foundation of China(Grant Nos.41002037,41102075,41230312)
文摘Affected by structural uplift, the Ordovician carbonate rockbed in the Tarim Basin, China, was exposed to dissolution and reformation of atmospheric precipitation many times, and formed a large quantity of karst caves serving as hydrocarbon reser- voir. However, drilling in Tahe area showed that many large karst caves, small pores and fractures are filled by calcite, result- ing in decrease in their reservoir ability. Calcite filled in the karst caves has very light oxygen isotopic composition and STSr/S（＇Sr ratio. Its c^OpDB ranges from -21.2%o to 13.3%o with the average of -16.3%e and its 87Sr/86Nr ratio ranges from 0.709561 to 0.710070 with the average of 0.709843. The isotope composition showed that calcite is related to atmospheric precipitation. Theoretic analyses indicated that the dissolving and filling actions of the precipitation on carbonate rocks are controlled by both thermodynamic and kinetic mechanisms. Among them, the thermodynamic factor determines that the pre- cipitation during its flow from the earth surface downward plays important roles on carbonate rocks from dissolution to satura- tion, further sedimentation, and finally filling. In other words, the depth of the karstification development is not unrestricted, but limited by the precipitation beneath the earth surface. On the other hand, the kinetic factor controls the intensity, depth, and breadth of the karstification development, that is, the karstification is also affected by topographic, geomorphologic, climatic factors, the degree of fracture or fault, etc. Therefore, subject to their joint effects, the karstification of the precipitation on the Ordovician carbonate rocks occurs only within a certain depth （most about 200 m） under the unconformity surface, deeper than which carbonate minerals begin to sedimentate and fill the karst caves that were formed previously.
基金supported by the National Natural Science Foundation of China (Grant No.50979063)
文摘One of the possible negative environmental effects of hydropower stations is the supersaturation of total dissolved gas (TDG) downstream of high-dams,which can lead to gas bubble disease or even death of fish. By taking the TDG as the main study object,the paper launched the TDG field observations on Zipingpu,Three Gorges,Ertan,Manwan,Dachaoshan,Gongzui and Ertan dams in China. The factors affecting TDG generation and dissipation were explored. Energy dissipation structures,spill rates and operation patterns were the main factors causing TDG supersaturation. TDG saturations are essentially the same in the hydro-electric tail water and in the upper reaches,so hydro-electric tail water can be less TDG supersaturated through mixing downstream. The main factors affecting the dissipation process of the supersaturated TDG were tributary convergence,water depth and turbulence. TDG supersaturation was unevenly distributed in both the vertical and transverse directions. This study is important because it adds to the accumulating experience of TDG field observations of dam projects in China,and because it objectively and impartially evaluates the impacts of supersaturated TDG. The study also provides field data and references for future studies of TDG supersaturation caused by high-dams.
