The two-stage dough mixing process was innovated to improve the qualities of bread made from potato flour(PF) and wheat flour at a ratio of 1:1(w/w). The final dough was first prepared from wheat flour before being ad...The two-stage dough mixing process was innovated to improve the qualities of bread made from potato flour(PF) and wheat flour at a ratio of 1:1(w/w). The final dough was first prepared from wheat flour before being added with PF. The effects of the method on enhancing the dough qualities were verified, and the distribution of water in gluten-gelatinized starch matrix of the doughs was investigated. We observed that the bread qualities were improved, as reflected by the increase of specific volume from 2.26 to 2.96 m L g^–1 and the decrease of crumb hardness from 417.93 to 255.57 g. The results from rheofermentometric measurements showed that the dough mixed using the developed mixing method had higher maximum dough height value, time of dough porosity appearance, and gas retention coefficient, as well as enhanced gluten matrix formation compared to that mixed by the traditional mixing method. The results from low-field nuclear magnetic resonance confirmed that the competitive water absorption between gluten and gelatinized starch could restrict the formation of gluten network in the dough mixed using the traditional mixing process. Using the novel mixing method, gluten could be sufficiently hydrated in stage 1, which could then weaken the competitive water absorption caused by gelatinized starch in stage 2;this could also be indicated by the greater mobility of proton in PF and better development of gluten network during mixing.展开更多
We report the measurement of the intensity difference squeezing via the non-degenerate four-wave mixing process in a rubidium atomic vapor medium. Two pairs of balanced detection systems are employed to measure the pr...We report the measurement of the intensity difference squeezing via the non-degenerate four-wave mixing process in a rubidium atomic vapor medium. Two pairs of balanced detection systems are employed to measure the probe and the conjugate beams, respectively. It is convenient to get the quantum shot noise limit, the squeezed and the amplified noise power spectra. We also investigate the influence of the input extra quadrature amplitude noise of the probe beam. The influence of the extra noise can be minimized and the squeezing can be optimized under the proper parameter condition. We measure the -3.7-dB intensity difference squeezing when the probe beam has a 3-dB extra quadrature amplitude noise. This result is slightly smaller than -4.1 dB when the ideal coherent light (no extra noise) for the probe beam is used.展开更多
The technology of cemented paste backfill(CPB)is an effective method for green mining.In CPB,mixing is a vital process aiming to prepare a paste that meets the non-stratification,non-segregation,and non-bleeding requi...The technology of cemented paste backfill(CPB)is an effective method for green mining.In CPB,mixing is a vital process aiming to prepare a paste that meets the non-stratification,non-segregation,and non-bleeding requirements.As a multiscale granular system,homogenization is one of the challenges in the paste-mixing process.Due to the high shearing,high concentration,and multiscale characteristics,paste exhibits complex rheological properties in the mixing process.An overview of the mesomechanics and structural evolution is presented in this review.The effects of various influencing factors on the paste's rheological properties were investigated,and the rheological models of the paste were outlined from the macroscopic and mesoscopic levels.The results show that the mechanical effects and structural evolution are the fundamental factors affecting the rheological properties of the paste.Existing problems and future development trends are presented to change the practice where the CPB process comes first and the theory lags.展开更多
In this paper,nonparametric estimation for a stationary strongly mixing and manifoldvalued process(X_(j))is considered.In this non-Euclidean and not necessarily i.i.d setting,we propose kernel density estimators of th...In this paper,nonparametric estimation for a stationary strongly mixing and manifoldvalued process(X_(j))is considered.In this non-Euclidean and not necessarily i.i.d setting,we propose kernel density estimators of the joint probability density function,of the conditional probability density functions and of the conditional expectations of functionals of X_(j)given the past behavior of the process.We prove the strong consistency of these estimators under sufficient conditions,and we illustrate their performance through simulation studies and real data analysis.展开更多
Different hydraulic retention times(HRTs)were tested in a mixed anoxic/oxic(A/O)system at 5C and 10C to investigate the effects of HRT and carrier on nitrogen removal in wastewater at low temperatures.The results show...Different hydraulic retention times(HRTs)were tested in a mixed anoxic/oxic(A/O)system at 5C and 10C to investigate the effects of HRT and carrier on nitrogen removal in wastewater at low temperatures.The results showed that the addition of the fillers improved the treatment effect of each index in the system.With an optimal HRT of 7.5 h at 5C,the removal efficiencies of NHþ4-N and total nitrogen(TN)reached 91.2%and 75.6%,respectively.With an HRT of 6 h at 10C,the removal efficiencies of NHþ4-N and TN were 96.7%and 82.9%,respectively.The results of high-throughput sequencing showed that the addition of the suspended carriers in the aerobic zone could improve the treatment efficiency of nitrogen at low temperatures.The microbial analysis indicated that the addition of the suspended carriers enhanced the enrichment of nitrogen removal bacteria.Nitrospira,Nitrotoga,and Nitrosomonas were found to be the bacteria responsible for nitrification,and their relative concentrations on the biofilm at 5C and 10C accounted for 98.11%,92.79%,and 69.98%of all biological samples,respectively.展开更多
The formation mechanism of the large hydrothermal sulfide deposit is a complex geological process involving many controlling factors. Mixing between hydrothermal fluid and seawater plays a key role in this process. Th...The formation mechanism of the large hydrothermal sulfide deposit is a complex geological process involving many controlling factors. Mixing between hydrothermal fluid and seawater plays a key role in this process. The results of the Ocean Drilling Program (ODP) indicate that mixing of the evolved seawater and hydrothermal fluid, which is wildly developed within the Trans-Atlantic Geo-Traverse (TAG) hydrothermal deposit, governs the internal structure and chemical compositions of the deposit to great extent. Taking the TAG field for example, the mixing processes of hydrothermal fluid with the seawater heated to different extent are calculated, so as to discuss the impact of hydrothermal fluid/seawater mixing on the formation process of the sulfide deposit. The results indicate that: (1) mixing between the heated seawater and hydrothermal fluid derived from the deep deposit is largely responsible for the wild precipitation of anhydrite within the TAG hydrothermal deposit; (2) 330-310℃ is a special temperature range in the mixing process; (3) the mixing and hydrothermal processes in different zones of the TAG hydrothermal deposit (TAG-1, TAG-2 and TAG-5, etc.) have been discussed based on the simulated results.展开更多
A continuous time and mixed state branching process is constructed by a scaling limit theorem of two-type Galton-Watson processes.The process can also be obtained by the pathwise unique solution to a stochastic equati...A continuous time and mixed state branching process is constructed by a scaling limit theorem of two-type Galton-Watson processes.The process can also be obtained by the pathwise unique solution to a stochastic equation system.From the stochastic equation system we derive the distribution of local jumps and give the exponential ergodicity in Wasserstein-type distances of the transition semigroup.Meanwhile,we study immigration structures associated with the process and prove the existence of the stationary distribution of the process with immigration.展开更多
By Analyzing the behavior and character of derivative security, the authors established a pricing model of multiattribute derivative security whose underlying asset pricing process is a mixed process, and obtained a n...By Analyzing the behavior and character of derivative security, the authors established a pricing model of multiattribute derivative security whose underlying asset pricing process is a mixed process, and obtained a new model for option pricing of multiattribute derivatives based on mixed process, and improved some original results.展开更多
It has been found that the static pressure distribution along the axial direction of liquid kerosene is lower than that of the gaseous kerosene under the same flow condition and overall equivalent ratio from previous ...It has been found that the static pressure distribution along the axial direction of liquid kerosene is lower than that of the gaseous kerosene under the same flow condition and overall equivalent ratio from previous studies.To further investigate this phenomenon,a compressible two-phase parallel simulation method is utilized to analyze the mixing and combustion characteristics of gaseous and liquid kerosene jets in a cavity-based supersonic combustor.The numerical results are consistent with the experiments and demonstrate that gaseous injection leads to a cavity shear layer that dives deeper into the cavity,forming two recirculation zones in the front and rear of the cavity.In contrast,the cavity shear layer is closer to the mainstream during liquid injection,and only a large recirculation zone is formed in the rear of the cavity.As a result of the cavity shear layer and the recirculating flow,the fuel vapor of gaseous injection accumulates in the front of the cavity,while for the liquid injection,the fuel vapor disperses in the cavity,cavity shear layer,and the region above,and the rear of the cavity has a higher fuel vapor concentration than the front.This unique fuel distribution causes the combustion area to be concentrated in the cavity during the gaseous injection but dispersed inside and downstream of the cavity during the liquid injection.As a result,forming a thermal throat under the same conditions is more challenging during liquid injection,and the generated static pressure distribution is lower than that during the gaseous injection.展开更多
Due to orographic blockage, a weak wind wake occurs in summer off northeast Vietnam in the South China Sea. Under the wind wake, warm water is observed from both high-resolution satellite data and hydrographic observa...Due to orographic blockage, a weak wind wake occurs in summer off northeast Vietnam in the South China Sea. Under the wind wake, warm water is observed from both high-resolution satellite data and hydrographic observations. The wake of warm water forms in June, continues to mature in July and August, starts to decay in September, and disappears in October. The warm water wake also shows robust diurnal variation – it intensifies during the day and weakens in the night. Warm water wakes can be generated through wind-induced mixing and thermal(latent heat flux) processes. In this paper, a mixed layer model is used to evaluate the relative importance of the two processes on seasonal and diurnal timescales, respectively. The results demonstrate that thermal processes make a greater contribution to the wake than wind-induced mixing processes on a seasonal timescale, while the warm water wake is dominated by wind-induced mixing processes on a diurnal timescale.展开更多
The expected water mixing process between Red/Dead Sea water during the proposed conveyance projects is the main target of this research. The project will ensue transporting Red Sea water to recover and maintain certa...The expected water mixing process between Red/Dead Sea water during the proposed conveyance projects is the main target of this research. The project will ensue transporting Red Sea water to recover and maintain certain level of the Dead Sea, mostly will reach <span><span><span style="font-family:;" "=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">-</span></span></span></span><span style="font-family:;" "="">395</span><span style="font-family:;" "=""> </span><span style="font-family:;" "="">m. It is found that, the two different water bodies with different EC values or different densities (salinities) are relatively divided by stable plane. This plane is defined as the BARZACH PLANE. In this study, the mixing process occurred between the Red Sea with the Dead Sea waters, located at 20</span><span style="font-family:;" "="">% </span><span style="font-family:;" "="">-</span><span style="font-family:;" "=""> </span><span style="font-family:;" "="">24% of the Dead Sea column depth based on the Barzach Plane level. During a laboratory experimental work, it is found that the mixed Red/Dead Sea water evaporates in a high rate until certain level where the solution attains oversaturated conditions with different dissolved solids. At this stage, a thin layer of solids suddenly formed and floated at the surface of the dense brine. The salinity of the captured water is so dense that floated salt layer cannot be dissolved. In addition, the formed floated salt layer at the surface prevents the below captured water to evaporate and at this stage, stalactites start to form until the excess dissolved solids are not oversaturated with any mineral.</span>展开更多
Future high-power-density engines require high level of intake boost.However,the effects of boosting on mixing,combustion and emissions in existing studies are inconsistent.In this paper,the mixing,combustion and emis...Future high-power-density engines require high level of intake boost.However,the effects of boosting on mixing,combustion and emissions in existing studies are inconsistent.In this paper,the mixing,combustion and emission characteristics with intake pressures of 100-400 kPa at low,medium and high loads are studied.The results show that the increase of intake pressures is conducive to the enhancement of air entrainment,while the air utilization ratios are reduced,thus requiring injection pressure to be optimized to effectively improve the mixing.For the intake pressures of 100 kPa,the average chemical reaction path is low-temperature reaction route,while the path of higher intake pressures is dominated by high-temperature pyrolysis.For soot emissions,when the equivalence ratio is lower than 0.175,the oxygen in the cylinder is suficient,so the effect of temperature decrease is more significant,which leads to the increase of soot emissions with the increase of intake pressures.Otherwise,the effect of increasing oxygen concentration is more significant,so soot decreases accordingly.When the peak of global temperature is lower than 1800 K,the effect of the increase of oxygen concentration is more dominant,so the NO_(x)emission increases with the increase of intake pressures.Otherwise,the rule of NOxemissions is consistent with temperature changes.展开更多
Let {S t H, t ≥ 0) be a linear combination of a Brownian motion and an independent sub-fractional Brownian motion with Hurst index 0 〈 H 〈 1. Its main properties are studied. They suggest that SH lies between the ...Let {S t H, t ≥ 0) be a linear combination of a Brownian motion and an independent sub-fractional Brownian motion with Hurst index 0 〈 H 〈 1. Its main properties are studied. They suggest that SH lies between the sub-fractional Brownian motion and the mixed fractional Brownian motion. We also determine the values of H for which SH is not a semi-martingale.展开更多
Fresh straw burning (SB) particles were generated in the laboratory by the combustion of rice straw and corn straw. The chemical composition and mixing state of the fresh SB particles were investigated by an Aerosol...Fresh straw burning (SB) particles were generated in the laboratory by the combustion of rice straw and corn straw. The chemical composition and mixing state of the fresh SB particles were investigated by an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS). Based on the mass spectral patterns, the SB particles were clustered into four major types: Salt, Organic Carbon (OC), Elemental Carbon (EC), and internally mixed particles of EC and OC (EC-OC). In addition, particles containing ash, polycyclic aromatic hydrocarbons, heavy metals or nicotine were also observed. Physical and chemical changes of the SB particles immediately after the emission were analyzed with highly time-resolved data. During the aging processes, the average particle size increased steadily. Freshly emitted organic compounds were gradu- ally oxidized to more oxygenated compounds in the OC- containing particles. Meanwhile, an important displace- ment reaction (2KCI+ SO24- KzSO4 + 2C1-) was observed. The marker ions for SB particles were optimized and applied to identify the SB particles in the ambient atmosphere. The fluctuation of the number fraction of ambient SB particles sorted by ATOFMS agrees well with that of water soluble K+ measured by an online ion chromatography, demonstrating that the optimized marker ions could be good tracers for SB particles in field measurements.展开更多
Spatial variations in phytoplankton community within a large mesotrophic reservoir (Miyun reservoir, North China) were investigated in relation to variations in physico-chemical properties, nutrient concentrations, ...Spatial variations in phytoplankton community within a large mesotrophic reservoir (Miyun reservoir, North China) were investigated in relation to variations in physico-chemical properties, nutrient concentrations, temperature and light conditions over a 5 month period in 2009. The dynamics of phytoplankton community was represented by the dominance of cyanobacteria through summer and fall, following with a short term dominance of chlorophyta in late fall, and a relatively high abundance of diatom in October; on the other hand, maximum phytoplankton biomass was recorded in the north shallow region of Miyun reservoir with a higher nutrients level. Particular attention was paid to the impacts of environmental conditions on the growth of two cyanobacteria genera, the toxin-producing Microcystis and the taste & odor-producing Oscillatoria. Microcystis biomass was in general greatly affected by water temperature and mixing depth/local water depth ratio in this reservoir, while the Oscillatoria biomass in the surface and middle layers was greatly affected by total dissolved phosphorus, and that in the bottom layer was related with the Secchi depth/local water depth ratio. Abundant Oscillatoria biomass was observed only in late September when Microcystis biomass decreased and allowed sufficient light go through.展开更多
基金supported by the National Natural Science Foundation of China (31701527)the National Key Research and Development Program of China (2017YFD0400401)+1 种基金the Policy Guidance Program of Jiangsu Province, China (SZ-SQ2017021)the Jiangsu Province “Collaborative Innovation Center of Food Safety and Quality Control” industry development program, China。
文摘The two-stage dough mixing process was innovated to improve the qualities of bread made from potato flour(PF) and wheat flour at a ratio of 1:1(w/w). The final dough was first prepared from wheat flour before being added with PF. The effects of the method on enhancing the dough qualities were verified, and the distribution of water in gluten-gelatinized starch matrix of the doughs was investigated. We observed that the bread qualities were improved, as reflected by the increase of specific volume from 2.26 to 2.96 m L g^–1 and the decrease of crumb hardness from 417.93 to 255.57 g. The results from rheofermentometric measurements showed that the dough mixed using the developed mixing method had higher maximum dough height value, time of dough porosity appearance, and gas retention coefficient, as well as enhanced gluten matrix formation compared to that mixed by the traditional mixing method. The results from low-field nuclear magnetic resonance confirmed that the competitive water absorption between gluten and gelatinized starch could restrict the formation of gluten network in the dough mixed using the traditional mixing process. Using the novel mixing method, gluten could be sufficiently hydrated in stage 1, which could then weaken the competitive water absorption caused by gelatinized starch in stage 2;this could also be indicated by the greater mobility of proton in PF and better development of gluten network during mixing.
基金supported by the National Basic Research Program of China (Grant No. 2011CB921601)the National Natural Science Foundation of China (Grant No. 11234008)+1 种基金the National Natural Science Foundation of China for Excellent Research Team (Grant No. 61121064)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20111401130001)
文摘We report the measurement of the intensity difference squeezing via the non-degenerate four-wave mixing process in a rubidium atomic vapor medium. Two pairs of balanced detection systems are employed to measure the probe and the conjugate beams, respectively. It is convenient to get the quantum shot noise limit, the squeezed and the amplified noise power spectra. We also investigate the influence of the input extra quadrature amplitude noise of the probe beam. The influence of the extra noise can be minimized and the squeezing can be optimized under the proper parameter condition. We measure the -3.7-dB intensity difference squeezing when the probe beam has a 3-dB extra quadrature amplitude noise. This result is slightly smaller than -4.1 dB when the ideal coherent light (no extra noise) for the probe beam is used.
基金financially supported by the National Key R&D Program of China (No.2022YFC2903803)the National Natural Science Foundation of China (No.52130404)+3 种基金China Postdoctoral Science Foundation (No.2021M690011)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110161)Postdoctor Research Foundation of Shunde Graduate School of University of Science and Technology Beijing (No.2021BH011)the Fundamental Research Funds for the Central Universities (No.FRF-TP-22-112A1)
文摘The technology of cemented paste backfill(CPB)is an effective method for green mining.In CPB,mixing is a vital process aiming to prepare a paste that meets the non-stratification,non-segregation,and non-bleeding requirements.As a multiscale granular system,homogenization is one of the challenges in the paste-mixing process.Due to the high shearing,high concentration,and multiscale characteristics,paste exhibits complex rheological properties in the mixing process.An overview of the mesomechanics and structural evolution is presented in this review.The effects of various influencing factors on the paste's rheological properties were investigated,and the rheological models of the paste were outlined from the macroscopic and mesoscopic levels.The results show that the mechanical effects and structural evolution are the fundamental factors affecting the rheological properties of the paste.Existing problems and future development trends are presented to change the practice where the CPB process comes first and the theory lags.
文摘In this paper,nonparametric estimation for a stationary strongly mixing and manifoldvalued process(X_(j))is considered.In this non-Euclidean and not necessarily i.i.d setting,we propose kernel density estimators of the joint probability density function,of the conditional probability density functions and of the conditional expectations of functionals of X_(j)given the past behavior of the process.We prove the strong consistency of these estimators under sufficient conditions,and we illustrate their performance through simulation studies and real data analysis.
基金supported by the National Natural Science Foundation of China(Grants No.51978233 and 52000057)the China Postdoctoral Science Foundation(Grant No.2020M680844).
文摘Different hydraulic retention times(HRTs)were tested in a mixed anoxic/oxic(A/O)system at 5C and 10C to investigate the effects of HRT and carrier on nitrogen removal in wastewater at low temperatures.The results showed that the addition of the fillers improved the treatment effect of each index in the system.With an optimal HRT of 7.5 h at 5C,the removal efficiencies of NHþ4-N and total nitrogen(TN)reached 91.2%and 75.6%,respectively.With an HRT of 6 h at 10C,the removal efficiencies of NHþ4-N and TN were 96.7%and 82.9%,respectively.The results of high-throughput sequencing showed that the addition of the suspended carriers in the aerobic zone could improve the treatment efficiency of nitrogen at low temperatures.The microbial analysis indicated that the addition of the suspended carriers enhanced the enrichment of nitrogen removal bacteria.Nitrospira,Nitrotoga,and Nitrosomonas were found to be the bacteria responsible for nitrification,and their relative concentrations on the biofilm at 5C and 10C accounted for 98.11%,92.79%,and 69.98%of all biological samples,respectively.
基金China Ocean Mineral Resources Research and Development Association program under contract No. DY115-02-1-01the National Basic Research Program of China ("973" Program) under contract No.G2000078503
文摘The formation mechanism of the large hydrothermal sulfide deposit is a complex geological process involving many controlling factors. Mixing between hydrothermal fluid and seawater plays a key role in this process. The results of the Ocean Drilling Program (ODP) indicate that mixing of the evolved seawater and hydrothermal fluid, which is wildly developed within the Trans-Atlantic Geo-Traverse (TAG) hydrothermal deposit, governs the internal structure and chemical compositions of the deposit to great extent. Taking the TAG field for example, the mixing processes of hydrothermal fluid with the seawater heated to different extent are calculated, so as to discuss the impact of hydrothermal fluid/seawater mixing on the formation process of the sulfide deposit. The results indicate that: (1) mixing between the heated seawater and hydrothermal fluid derived from the deep deposit is largely responsible for the wild precipitation of anhydrite within the TAG hydrothermal deposit; (2) 330-310℃ is a special temperature range in the mixing process; (3) the mixing and hydrothermal processes in different zones of the TAG hydrothermal deposit (TAG-1, TAG-2 and TAG-5, etc.) have been discussed based on the simulated results.
基金supported by the National Key R&D Program of China(2020YFA0712900)the National Natural Science Foundation of China(11531001).
文摘A continuous time and mixed state branching process is constructed by a scaling limit theorem of two-type Galton-Watson processes.The process can also be obtained by the pathwise unique solution to a stochastic equation system.From the stochastic equation system we derive the distribution of local jumps and give the exponential ergodicity in Wasserstein-type distances of the transition semigroup.Meanwhile,we study immigration structures associated with the process and prove the existence of the stationary distribution of the process with immigration.
基金Supported by the Natural Science Foundation of China (No. 79700022 ) and the AeronauticalFoundation of China(No. 95J55002 )
文摘By Analyzing the behavior and character of derivative security, the authors established a pricing model of multiattribute derivative security whose underlying asset pricing process is a mixed process, and obtained a new model for option pricing of multiattribute derivatives based on mixed process, and improved some original results.
基金supported by the National Natural Science Foundation of China (Nos.92252206,11925207,T2221002 and 12102472)。
文摘It has been found that the static pressure distribution along the axial direction of liquid kerosene is lower than that of the gaseous kerosene under the same flow condition and overall equivalent ratio from previous studies.To further investigate this phenomenon,a compressible two-phase parallel simulation method is utilized to analyze the mixing and combustion characteristics of gaseous and liquid kerosene jets in a cavity-based supersonic combustor.The numerical results are consistent with the experiments and demonstrate that gaseous injection leads to a cavity shear layer that dives deeper into the cavity,forming two recirculation zones in the front and rear of the cavity.In contrast,the cavity shear layer is closer to the mainstream during liquid injection,and only a large recirculation zone is formed in the rear of the cavity.As a result of the cavity shear layer and the recirculating flow,the fuel vapor of gaseous injection accumulates in the front of the cavity,while for the liquid injection,the fuel vapor disperses in the cavity,cavity shear layer,and the region above,and the rear of the cavity has a higher fuel vapor concentration than the front.This unique fuel distribution causes the combustion area to be concentrated in the cavity during the gaseous injection but dispersed inside and downstream of the cavity during the liquid injection.As a result,forming a thermal throat under the same conditions is more challenging during liquid injection,and the generated static pressure distribution is lower than that during the gaseous injection.
基金The National Science Fund of China for Distinguished Young Scholars(NSFDYS)under contract No.41125019the National Basic Research Program of China under contract Nos 2012CB955601 and 2013CB430301the Basic Research Program of Second Institute of Oceanography,State Oceanic Administration of China under contract No.JT1301
文摘Due to orographic blockage, a weak wind wake occurs in summer off northeast Vietnam in the South China Sea. Under the wind wake, warm water is observed from both high-resolution satellite data and hydrographic observations. The wake of warm water forms in June, continues to mature in July and August, starts to decay in September, and disappears in October. The warm water wake also shows robust diurnal variation – it intensifies during the day and weakens in the night. Warm water wakes can be generated through wind-induced mixing and thermal(latent heat flux) processes. In this paper, a mixed layer model is used to evaluate the relative importance of the two processes on seasonal and diurnal timescales, respectively. The results demonstrate that thermal processes make a greater contribution to the wake than wind-induced mixing processes on a seasonal timescale, while the warm water wake is dominated by wind-induced mixing processes on a diurnal timescale.
文摘The expected water mixing process between Red/Dead Sea water during the proposed conveyance projects is the main target of this research. The project will ensue transporting Red Sea water to recover and maintain certain level of the Dead Sea, mostly will reach <span><span><span style="font-family:;" "=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">-</span></span></span></span><span style="font-family:;" "="">395</span><span style="font-family:;" "=""> </span><span style="font-family:;" "="">m. It is found that, the two different water bodies with different EC values or different densities (salinities) are relatively divided by stable plane. This plane is defined as the BARZACH PLANE. In this study, the mixing process occurred between the Red Sea with the Dead Sea waters, located at 20</span><span style="font-family:;" "="">% </span><span style="font-family:;" "="">-</span><span style="font-family:;" "=""> </span><span style="font-family:;" "="">24% of the Dead Sea column depth based on the Barzach Plane level. During a laboratory experimental work, it is found that the mixed Red/Dead Sea water evaporates in a high rate until certain level where the solution attains oversaturated conditions with different dissolved solids. At this stage, a thin layer of solids suddenly formed and floated at the surface of the dense brine. The salinity of the captured water is so dense that floated salt layer cannot be dissolved. In addition, the formed floated salt layer at the surface prevents the below captured water to evaporate and at this stage, stalactites start to form until the excess dissolved solids are not oversaturated with any mineral.</span>
基金supported by the Natural Science Foundation of China(No.51921004 and U2241262)。
文摘Future high-power-density engines require high level of intake boost.However,the effects of boosting on mixing,combustion and emissions in existing studies are inconsistent.In this paper,the mixing,combustion and emission characteristics with intake pressures of 100-400 kPa at low,medium and high loads are studied.The results show that the increase of intake pressures is conducive to the enhancement of air entrainment,while the air utilization ratios are reduced,thus requiring injection pressure to be optimized to effectively improve the mixing.For the intake pressures of 100 kPa,the average chemical reaction path is low-temperature reaction route,while the path of higher intake pressures is dominated by high-temperature pyrolysis.For soot emissions,when the equivalence ratio is lower than 0.175,the oxygen in the cylinder is suficient,so the effect of temperature decrease is more significant,which leads to the increase of soot emissions with the increase of intake pressures.Otherwise,the effect of increasing oxygen concentration is more significant,so soot decreases accordingly.When the peak of global temperature is lower than 1800 K,the effect of the increase of oxygen concentration is more dominant,so the NO_(x)emission increases with the increase of intake pressures.Otherwise,the rule of NOxemissions is consistent with temperature changes.
文摘Let {S t H, t ≥ 0) be a linear combination of a Brownian motion and an independent sub-fractional Brownian motion with Hurst index 0 〈 H 〈 1. Its main properties are studied. They suggest that SH lies between the sub-fractional Brownian motion and the mixed fractional Brownian motion. We also determine the values of H for which SH is not a semi-martingale.
基金This work was supported by The National Natural Science Foundation of China (Grant Nos. 21177027 and 41275126), Ministry of Science and Technology of China (2012YQ220113-4), the Science & Technology Commission of Shanghai Municipality (12DJ1400100, 14XD 1400600), and the Jiangsu Provincial Collaborative Innovation Center of Climate Change.
文摘Fresh straw burning (SB) particles were generated in the laboratory by the combustion of rice straw and corn straw. The chemical composition and mixing state of the fresh SB particles were investigated by an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS). Based on the mass spectral patterns, the SB particles were clustered into four major types: Salt, Organic Carbon (OC), Elemental Carbon (EC), and internally mixed particles of EC and OC (EC-OC). In addition, particles containing ash, polycyclic aromatic hydrocarbons, heavy metals or nicotine were also observed. Physical and chemical changes of the SB particles immediately after the emission were analyzed with highly time-resolved data. During the aging processes, the average particle size increased steadily. Freshly emitted organic compounds were gradu- ally oxidized to more oxygenated compounds in the OC- containing particles. Meanwhile, an important displace- ment reaction (2KCI+ SO24- KzSO4 + 2C1-) was observed. The marker ions for SB particles were optimized and applied to identify the SB particles in the ambient atmosphere. The fluctuation of the number fraction of ambient SB particles sorted by ATOFMS agrees well with that of water soluble K+ measured by an online ion chromatography, demonstrating that the optimized marker ions could be good tracers for SB particles in field measurements.
基金supported by the National Natural Science Foundation of China (No. 50938007)
文摘Spatial variations in phytoplankton community within a large mesotrophic reservoir (Miyun reservoir, North China) were investigated in relation to variations in physico-chemical properties, nutrient concentrations, temperature and light conditions over a 5 month period in 2009. The dynamics of phytoplankton community was represented by the dominance of cyanobacteria through summer and fall, following with a short term dominance of chlorophyta in late fall, and a relatively high abundance of diatom in October; on the other hand, maximum phytoplankton biomass was recorded in the north shallow region of Miyun reservoir with a higher nutrients level. Particular attention was paid to the impacts of environmental conditions on the growth of two cyanobacteria genera, the toxin-producing Microcystis and the taste & odor-producing Oscillatoria. Microcystis biomass was in general greatly affected by water temperature and mixing depth/local water depth ratio in this reservoir, while the Oscillatoria biomass in the surface and middle layers was greatly affected by total dissolved phosphorus, and that in the bottom layer was related with the Secchi depth/local water depth ratio. Abundant Oscillatoria biomass was observed only in late September when Microcystis biomass decreased and allowed sufficient light go through.