Small watersheds are the basic composition unit of the Loess Plateau in China. An accurate estimation of vegetation net primary productivity （NPP） is of great significance for eco-benefit evaluation in small watersh...Small watersheds are the basic composition unit of the Loess Plateau in China. An accurate estimation of vegetation net primary productivity （NPP） is of great significance for eco-benefit evaluation in small watershed management in this region. Here we describe the development and testing of a vegetation-producing process model （VPP） of a small watershed in the Loess Plateau. The model couples three modules： radiation adjustment; soil hydrological processes; and vegetation carbon assimilation. Model validation indicates that the VPP model can be used to estimate the NPP of small watersheds in the region. With the VPP model, we estimated the spatial NPP distributions in the Yangou watershed for 2007. The results show that in the Yangou watershed the NPP is relatively low, averaging 168 g C/（m^2.a）. Trees and shrubs have a higher NPP than crops and grasses. The NPP is larger on the partly shaded and shaded slopes than on the partly sunny and sunny slopes. The NPP on the slopes increases gradually on 0-20° slopes and decreases slightly on slopes steeper than 20°. Our simulation indicates that the vegetation type is the most important factor in determining the NPP distribution in small watersheds in the Loess Plateau.展开更多
This paper describes empirical research on the model, optimization and supervisory control of beer fermentation.Conditions in the laboratory were made as similar as possible to brewery industry conditions. Since mathe...This paper describes empirical research on the model, optimization and supervisory control of beer fermentation.Conditions in the laboratory were made as similar as possible to brewery industry conditions. Since mathematical models that consider realistic industrial conditions were not available, a new mathematical model design involving industrial conditions was first developed. Batch fermentations are multiobjective dynamic processes that must be guided along optimal paths to obtain good results.The paper describes a direct way to apply a Pareto set approach with multiobjective evolutionary algorithms (MOEAs).Successful finding of optimal ways to drive these processes were reported.Once obtained, the mathematical fermentation model was used to optimize the fermentation process by using an intelligent control based on certain rules.展开更多
The factors affecting the developmcnt of Sinopec lubricating oil were analyzed in this paper, and an analytic hierarchy process （AHP） model for selecting lubricating-oil producing bases was developed. By using this ...The factors affecting the developmcnt of Sinopec lubricating oil were analyzed in this paper, and an analytic hierarchy process （AHP） model for selecting lubricating-oil producing bases was developed. By using this model, nine lubricating oil producing companies under Sinopec were comprehensively evaluated. The evaluation result showed that the Maoming Lubricating Oil Company （Guangdong province）, Jingmen Lubricating Oil Company （Hubei province） and Changcheng Lube Oil Company （Beijing） are top three choices, and should be developed preferentially for the development of Sinopec producing bases of lubricating oil in the future. The conclusions provide the theoretical basis for selecting lubricating oil producing bases for decision makers.展开更多
The true stress-true strain curves of Ti-6Al-2Zr-IMO-IV alloy with hydrogen were obtained by hot compression test. The microstructures of the alloy before and after thermo-compression were observed. The apparent activ...The true stress-true strain curves of Ti-6Al-2Zr-IMO-IV alloy with hydrogen were obtained by hot compression test. The microstructures of the alloy before and after thermo-compression were observed. The apparent activation energies of deformation were calculated for the alloy with and without hydrogen. The behavior and mechanism of deformation for hydrogenated Ti-6A1-2Zr-IMO-IV alloy at high temperature were analyzed. The relationship between hydrogenation time and hydrogen content at 800 ℃ can be expressed as the equation： CH（t）=1.2-1.2exp（-t/120）. The true stress-true strain curves of hot compression for Ti-6Al-2Zr-IMO-IV alloy with hydrogen first move down and then move up as hydrogen content increases. Appropriate hydrogen content can reduce the peak of flow stress to minimal value. The apparent activation energies of deformation of the alloy with 0.47% hydrogen content and without hydrogen were calculated as 140 kJ·mol^-1 and 390 kJ-mol^-1, respectively, at 800 ℃ and at strain rate 8.3×10^4 s^-1. The apparent activation energy of deformation increases when the strain rate enhances from 8.3×10^-4 s^-1 to 8.3×10^-2 s^-1.展开更多
The objective of this study was to evaluate characteristics of processed cheese made from salt Ras cheese whey and young Cheddar containing exopolysaccharide producing cultures (EPS) as compared with those in cheese m...The objective of this study was to evaluate characteristics of processed cheese made from salt Ras cheese whey and young Cheddar containing exopolysaccharide producing cultures (EPS) as compared with those in cheese made from EPS-negative cheeses. Processed cheeses were manufactured using young (1 day) or 1-month-old EPS-positive or EPSnegative Cheddar cheese and replacing the added water by Ras cheese whey or ultrafiltrated (UF) whey. Moisture and fat of processed cheese were standardized to 54% and 23%, respectively. Exopolysaccharide-positive processed cheese was softer, less chewy and gummy than the EPS-negative cheeses. The hardness and chewiness were lower in processed cheeses made from 1-month-old Cheddar than in the corresponding cheeses made from 1-day-old Cheddar cheese. Sensory scores for texture of EPS positive processed cheeses were higher than those of the EPS-negative cheeses. Generally, processed cheese made from replacing all added water with whey received higher scores in flavor and overall than did the corresponding cheeses made without whey. The obtained results are showing promise for application of salt whey in processed cheese making.展开更多
This paper introduces some concepts such as q- process in random environment, Laplace transformation, ergodic potential kernel, error function and some basic lemmas.We study the continuity and Laplace transformation o...This paper introduces some concepts such as q- process in random environment, Laplace transformation, ergodic potential kernel, error function and some basic lemmas.We study the continuity and Laplace transformation of random transition function. Finally, we give the sufficient condition for the existence of ergodic potential kernel for homogeneous q- processes in random environments.展开更多
Vegetation net primary productivity(NPP)is a sensitive indicator to characterize the response of terrestrial ecosystems to the climate change.Projections of the NPP changes of the Loess Plateau under future climate sc...Vegetation net primary productivity(NPP)is a sensitive indicator to characterize the response of terrestrial ecosystems to the climate change.Projections of the NPP changes of the Loess Plateau under future climate scenarios have great significances in revealing the interactions among terrestrial ecosystems and climatic systems,as well as instructing future vegetation construction of this region.Here,we carried out a case study on the Yangou watershed in the Loess Plateau.Using the vegetation-producing process model(VPP)established for such small watersheds,we simulated the NPP of the Yangou watershed under different scenarios of climate changes.The results showed that the NPP significandy increased with the precipitation increasing and evidently decreased with the temperature increasing where the climate change occurred in the whole year or in the summer half year.However,where the climate change occurred in the winter half year,the increased precipitation had little effect on the NPP,and the increased temperature significantly reduced the NPP.There were clear differences among the response sensitivities of different vegetation types with trees and shrubs were more sensitive to the changes in temperature and precipitation than crops and grasses.Currently,the most favourable climate change scenario to the NPP in the Yangou watershed was T0P15 under which the precipitation increased by 15%and the temperature did not changed,in the whole year;in the meantime,the most unfavourable climate change scenarios was T2P-15 under which the precipitation declined by 15%and the temperature increased by 2℃,in the whole year.展开更多
A major portion of the beneficial effect of mesenchymal stem cells (MSC) is due to the production of trophic and angiogenic factors by these cells, and one of the efforts to improve the therapeutic efficacy of these c...A major portion of the beneficial effect of mesenchymal stem cells (MSC) is due to the production of trophic and angiogenic factors by these cells, and one of the efforts to improve the therapeutic efficacy of these cells lies in enhancing this capacity. Since there is complement activation in all areas of tissue injury, and both C3a and C5a activate MSC, it was asked whether stimulation with C3a or C5a would upregulate the production of trophic factors by MSC. C3a caused significant up-regulation of various angiogenic factors, including VEGF, CXCL8/IL-8 and IL-6. In contrast there was no detectable production of the pro-inflammatory cytokines TNF-α and IL-1β in spite of nuclear translocation of NFκB. Although C5a also caused moderate up-regulation of angiogenic factors, the effect was borderline significant. Furthermore the production of angiogenic factors induced by C3a was of physiological relevance: Supernatants of MSCs cultured under serum-free conditions induced minimal tube formation of HUVECs as an in vitro measure of angiogenesis;tube formation was considerably enhanced, when supernatants from C3a-stimulated MSC were used, while C3a itself had no direct angiogenic effect on HUVECs. The signaling cascade responsible for the production of angiogenic factors by C3a or C5a could be defined as activation of the rho cascade which was necessary for nuclear translocation of NFκB p65 and of phospho-ERK1/2. Although rho was only transiently activated, inhibition of the rho or “downstream of it” of the NFκB pathway, prevented C3a-and C5a-induced up-regulation of angiogenic factors.展开更多
For syngas production, the combustion of fossil fuels produces large amounts of CO2 as a greenhouse gas annually which intensifies global warming. In this study, chemical looping combustion （CLC） has been utilized f...For syngas production, the combustion of fossil fuels produces large amounts of CO2 as a greenhouse gas annually which intensifies global warming. In this study, chemical looping combustion （CLC） has been utilized for the elimination of CO2 emission to atmosphere during simultaneous syngas production with different H2/CO ratio in steam reforming of methane （SR） and dry reforming of methane （DR） in a CLC-SR-DR configuration. In CLC-SR-DR with 184 reformer tubes （similar to an industrial scale steam reformer in Zagros Petrochemical Company, Assaluyeh, Iran）, DR reaction occurs over Rh-based catalysts in 31 tubes. Also, SR reaction is happened over Ni-based catalysts in 153 tubes. CLC via employment of Mn-based oxygen carriers supplies heat for DR and SR reactions and produces CO2 and H2O as raw materials simultaneously. A steady state heterogeneous catalytic reaction model is applied to analyze the performance and applicability of the proposed CLC-SR-DR configuration. Simulation results show that combustion efficiency reached 1 at the outlet of fuel reactor （FR）. Therefore, pure CO2 and H2O can be recycled to DR and SR sides, respectively. Also, CH4 conversion reached 0.2803 and 0.7275 at the outlet of SR and DR sides, respectively. Simulation results indicate that, 3223 kmol.h-l syngas with a H2/CO ratio equal to 9.826 was produced in SR side of CLC-SR-DR. After that, 1844 kmol.h-1 syngas with a H2/CO ratio equal to 0.986 was achieved in DR side of CLC-SR-DR. Results illustrate that by increasing the number of DR tubes to 50 tubes and considering 184 fixed total tubes in CLC-SR-DR, CH4 conversions in SR and DR sides decreased 2.69% and 3.31%, respectively. However, this subject caused total syngas production in SR and DR sides （in all of 184 tubes） enhance to 5427 kmol-h-1. Finally, thermal and molar behaviors of the proposed configuration demonstrate that CLC-SR-DR is applicable for simultaneous syngas production with high and low Hx/CO ratios in an environmental friendly process.展开更多
The Ojarly gas field,the major supplier of the Project PhaseⅡof the Right Bank of the Amu Darya River,is just small but valuable like a golden bean,although it has good reservoir properties and a high gas production ...The Ojarly gas field,the major supplier of the Project PhaseⅡof the Right Bank of the Amu Darya River,is just small but valuable like a golden bean,although it has good reservoir properties and a high gas production capacity,the occurrence of continuous sharp decline of pressure in the well production shows a great difference from the previous well test program.In view of this,an integrated analysis method was established for the whole gas well production process to discover the three main reasons causing the abnormal well pressure.First,the formation energy and pressure dropped so fast that the wellhead pressure also fell over the period.Second,there was abnormal fluids pressure drop in the wellbore tube and throttling effect might occur in the production tube,so the pressure drop became abnormally increased.Third,due to the abnormally-increasing gas-yield pressure drop and unusually-decreasing gas productivity,the wellhead oil pressure dropped significantly.Also,through dynamic monitoring and in-depth analysis,it is also considered that due to the high density of drilling fluids and well-developed pores and caverns in the reservoirs,more and more barites separated from the fluids would be settled down covering the pay zones,so both the gas-generating capacity and production pressure significantly decreased.On this basis,some technical countermeasures were taken such as re-stimulation of reservoirs,removal of gas-producing channels,increase of seepage capacity,etc.In addition,by use of sand-flushing and acidizing,both the comprehensive skin factor and the production pressure drop were reduced to improve the well gas production capacity and maintain high productivity effectively.This study provides a technical support for long-term sustainable development and production of this gas field.展开更多
Objective With the rapid development of mobile power and electronic vehicles, the application of lithium is in the ascendant, and the contradiction between its supply and demand is prominent.
基金financed by the Strategic Priority Research Program (XDA05050403)the Key Research Program of Chinese Academy of Sciences (KZZD-EW-04)
文摘Small watersheds are the basic composition unit of the Loess Plateau in China. An accurate estimation of vegetation net primary productivity （NPP） is of great significance for eco-benefit evaluation in small watershed management in this region. Here we describe the development and testing of a vegetation-producing process model （VPP） of a small watershed in the Loess Plateau. The model couples three modules： radiation adjustment; soil hydrological processes; and vegetation carbon assimilation. Model validation indicates that the VPP model can be used to estimate the NPP of small watersheds in the region. With the VPP model, we estimated the spatial NPP distributions in the Yangou watershed for 2007. The results show that in the Yangou watershed the NPP is relatively low, averaging 168 g C/（m^2.a）. Trees and shrubs have a higher NPP than crops and grasses. The NPP is larger on the partly shaded and shaded slopes than on the partly sunny and sunny slopes. The NPP on the slopes increases gradually on 0-20° slopes and decreases slightly on slopes steeper than 20°. Our simulation indicates that the vegetation type is the most important factor in determining the NPP distribution in small watersheds in the Loess Plateau.
文摘This paper describes empirical research on the model, optimization and supervisory control of beer fermentation.Conditions in the laboratory were made as similar as possible to brewery industry conditions. Since mathematical models that consider realistic industrial conditions were not available, a new mathematical model design involving industrial conditions was first developed. Batch fermentations are multiobjective dynamic processes that must be guided along optimal paths to obtain good results.The paper describes a direct way to apply a Pareto set approach with multiobjective evolutionary algorithms (MOEAs).Successful finding of optimal ways to drive these processes were reported.Once obtained, the mathematical fermentation model was used to optimize the fermentation process by using an intelligent control based on certain rules.
文摘The factors affecting the developmcnt of Sinopec lubricating oil were analyzed in this paper, and an analytic hierarchy process （AHP） model for selecting lubricating-oil producing bases was developed. By using this model, nine lubricating oil producing companies under Sinopec were comprehensively evaluated. The evaluation result showed that the Maoming Lubricating Oil Company （Guangdong province）, Jingmen Lubricating Oil Company （Hubei province） and Changcheng Lube Oil Company （Beijing） are top three choices, and should be developed preferentially for the development of Sinopec producing bases of lubricating oil in the future. The conclusions provide the theoretical basis for selecting lubricating oil producing bases for decision makers.
基金supported by the National Natural Science Foundation of China(No.50671028)
文摘The true stress-true strain curves of Ti-6Al-2Zr-IMO-IV alloy with hydrogen were obtained by hot compression test. The microstructures of the alloy before and after thermo-compression were observed. The apparent activation energies of deformation were calculated for the alloy with and without hydrogen. The behavior and mechanism of deformation for hydrogenated Ti-6A1-2Zr-IMO-IV alloy at high temperature were analyzed. The relationship between hydrogenation time and hydrogen content at 800 ℃ can be expressed as the equation： CH（t）=1.2-1.2exp（-t/120）. The true stress-true strain curves of hot compression for Ti-6Al-2Zr-IMO-IV alloy with hydrogen first move down and then move up as hydrogen content increases. Appropriate hydrogen content can reduce the peak of flow stress to minimal value. The apparent activation energies of deformation of the alloy with 0.47% hydrogen content and without hydrogen were calculated as 140 kJ·mol^-1 and 390 kJ-mol^-1, respectively, at 800 ℃ and at strain rate 8.3×10^4 s^-1. The apparent activation energy of deformation increases when the strain rate enhances from 8.3×10^-4 s^-1 to 8.3×10^-2 s^-1.
文摘The objective of this study was to evaluate characteristics of processed cheese made from salt Ras cheese whey and young Cheddar containing exopolysaccharide producing cultures (EPS) as compared with those in cheese made from EPS-negative cheeses. Processed cheeses were manufactured using young (1 day) or 1-month-old EPS-positive or EPSnegative Cheddar cheese and replacing the added water by Ras cheese whey or ultrafiltrated (UF) whey. Moisture and fat of processed cheese were standardized to 54% and 23%, respectively. Exopolysaccharide-positive processed cheese was softer, less chewy and gummy than the EPS-negative cheeses. The hardness and chewiness were lower in processed cheeses made from 1-month-old Cheddar than in the corresponding cheeses made from 1-day-old Cheddar cheese. Sensory scores for texture of EPS positive processed cheeses were higher than those of the EPS-negative cheeses. Generally, processed cheese made from replacing all added water with whey received higher scores in flavor and overall than did the corresponding cheeses made without whey. The obtained results are showing promise for application of salt whey in processed cheese making.
基金Supported by the National Natural Science Foundation of China (10371092)
文摘This paper introduces some concepts such as q- process in random environment, Laplace transformation, ergodic potential kernel, error function and some basic lemmas.We study the continuity and Laplace transformation of random transition function. Finally, we give the sufficient condition for the existence of ergodic potential kernel for homogeneous q- processes in random environments.
基金Key Research Program of the Chinese Academy of Sciences(KZZD-EW-04)West Light Foundation of the Chinese Academy of Sciences and Funds of State Key Laboratory of Loess and Quaternary Geology,Chinese Academy of Sciences(SKLLQG1123)
文摘Vegetation net primary productivity(NPP)is a sensitive indicator to characterize the response of terrestrial ecosystems to the climate change.Projections of the NPP changes of the Loess Plateau under future climate scenarios have great significances in revealing the interactions among terrestrial ecosystems and climatic systems,as well as instructing future vegetation construction of this region.Here,we carried out a case study on the Yangou watershed in the Loess Plateau.Using the vegetation-producing process model(VPP)established for such small watersheds,we simulated the NPP of the Yangou watershed under different scenarios of climate changes.The results showed that the NPP significandy increased with the precipitation increasing and evidently decreased with the temperature increasing where the climate change occurred in the whole year or in the summer half year.However,where the climate change occurred in the winter half year,the increased precipitation had little effect on the NPP,and the increased temperature significantly reduced the NPP.There were clear differences among the response sensitivities of different vegetation types with trees and shrubs were more sensitive to the changes in temperature and precipitation than crops and grasses.Currently,the most favourable climate change scenario to the NPP in the Yangou watershed was T0P15 under which the precipitation increased by 15%and the temperature did not changed,in the whole year;in the meantime,the most unfavourable climate change scenarios was T2P-15 under which the precipitation declined by 15%and the temperature increased by 2℃,in the whole year.
文摘A major portion of the beneficial effect of mesenchymal stem cells (MSC) is due to the production of trophic and angiogenic factors by these cells, and one of the efforts to improve the therapeutic efficacy of these cells lies in enhancing this capacity. Since there is complement activation in all areas of tissue injury, and both C3a and C5a activate MSC, it was asked whether stimulation with C3a or C5a would upregulate the production of trophic factors by MSC. C3a caused significant up-regulation of various angiogenic factors, including VEGF, CXCL8/IL-8 and IL-6. In contrast there was no detectable production of the pro-inflammatory cytokines TNF-α and IL-1β in spite of nuclear translocation of NFκB. Although C5a also caused moderate up-regulation of angiogenic factors, the effect was borderline significant. Furthermore the production of angiogenic factors induced by C3a was of physiological relevance: Supernatants of MSCs cultured under serum-free conditions induced minimal tube formation of HUVECs as an in vitro measure of angiogenesis;tube formation was considerably enhanced, when supernatants from C3a-stimulated MSC were used, while C3a itself had no direct angiogenic effect on HUVECs. The signaling cascade responsible for the production of angiogenic factors by C3a or C5a could be defined as activation of the rho cascade which was necessary for nuclear translocation of NFκB p65 and of phospho-ERK1/2. Although rho was only transiently activated, inhibition of the rho or “downstream of it” of the NFκB pathway, prevented C3a-and C5a-induced up-regulation of angiogenic factors.
文摘For syngas production, the combustion of fossil fuels produces large amounts of CO2 as a greenhouse gas annually which intensifies global warming. In this study, chemical looping combustion （CLC） has been utilized for the elimination of CO2 emission to atmosphere during simultaneous syngas production with different H2/CO ratio in steam reforming of methane （SR） and dry reforming of methane （DR） in a CLC-SR-DR configuration. In CLC-SR-DR with 184 reformer tubes （similar to an industrial scale steam reformer in Zagros Petrochemical Company, Assaluyeh, Iran）, DR reaction occurs over Rh-based catalysts in 31 tubes. Also, SR reaction is happened over Ni-based catalysts in 153 tubes. CLC via employment of Mn-based oxygen carriers supplies heat for DR and SR reactions and produces CO2 and H2O as raw materials simultaneously. A steady state heterogeneous catalytic reaction model is applied to analyze the performance and applicability of the proposed CLC-SR-DR configuration. Simulation results show that combustion efficiency reached 1 at the outlet of fuel reactor （FR）. Therefore, pure CO2 and H2O can be recycled to DR and SR sides, respectively. Also, CH4 conversion reached 0.2803 and 0.7275 at the outlet of SR and DR sides, respectively. Simulation results indicate that, 3223 kmol.h-l syngas with a H2/CO ratio equal to 9.826 was produced in SR side of CLC-SR-DR. After that, 1844 kmol.h-1 syngas with a H2/CO ratio equal to 0.986 was achieved in DR side of CLC-SR-DR. Results illustrate that by increasing the number of DR tubes to 50 tubes and considering 184 fixed total tubes in CLC-SR-DR, CH4 conversions in SR and DR sides decreased 2.69% and 3.31%, respectively. However, this subject caused total syngas production in SR and DR sides （in all of 184 tubes） enhance to 5427 kmol-h-1. Finally, thermal and molar behaviors of the proposed configuration demonstrate that CLC-SR-DR is applicable for simultaneous syngas production with high and low Hx/CO ratios in an environmental friendly process.
基金CNPC Scientific Research and Technology DevelopmentProject “Key technology research and application for natural gas developmentof 16.5 m^(3) in the Right Bank of the Amu-Darya River, Turkmenistan” (No.:2011E-2505)National Science and Technology Major Project “Demonstra-tion Project of Natural Gas Development in Middle Zone of the Right Bank ofthe Amu-Darya River” (No.: 2011ZX05059).
文摘The Ojarly gas field,the major supplier of the Project PhaseⅡof the Right Bank of the Amu Darya River,is just small but valuable like a golden bean,although it has good reservoir properties and a high gas production capacity,the occurrence of continuous sharp decline of pressure in the well production shows a great difference from the previous well test program.In view of this,an integrated analysis method was established for the whole gas well production process to discover the three main reasons causing the abnormal well pressure.First,the formation energy and pressure dropped so fast that the wellhead pressure also fell over the period.Second,there was abnormal fluids pressure drop in the wellbore tube and throttling effect might occur in the production tube,so the pressure drop became abnormally increased.Third,due to the abnormally-increasing gas-yield pressure drop and unusually-decreasing gas productivity,the wellhead oil pressure dropped significantly.Also,through dynamic monitoring and in-depth analysis,it is also considered that due to the high density of drilling fluids and well-developed pores and caverns in the reservoirs,more and more barites separated from the fluids would be settled down covering the pay zones,so both the gas-generating capacity and production pressure significantly decreased.On this basis,some technical countermeasures were taken such as re-stimulation of reservoirs,removal of gas-producing channels,increase of seepage capacity,etc.In addition,by use of sand-flushing and acidizing,both the comprehensive skin factor and the production pressure drop were reduced to improve the well gas production capacity and maintain high productivity effectively.This study provides a technical support for long-term sustainable development and production of this gas field.
基金financially supported by China Geological Survey(grant No.12120113057300)the National Natural Science Foundation of China(grant No.41502082)
文摘Objective With the rapid development of mobile power and electronic vehicles, the application of lithium is in the ascendant, and the contradiction between its supply and demand is prominent.
