Nonferrous mining activities are some of the largest sources of heavy metals emissions into the environment and China is one of the largest producers and consumers of lead and zinc in the world.The cumulative producti...Nonferrous mining activities are some of the largest sources of heavy metals emissions into the environment and China is one of the largest producers and consumers of lead and zinc in the world.The cumulative productions and emissions of lead and zinc from mining-related activities in China were estimated.Up to 2007,the cumulative productions of lead and zinc in China were estimated to be about 6.69 and 12.59 Mt,respectively;and about 1.62 Mt lead and 3.32 Mt zinc emitted into the ambient environment during the mining,processing and smelting activities,representing 24.39% and 26.36% cumulative production,respectively.Among these three types of mining-related activities,mineral processing contributes the most to the total emission of 50.67% lead and 45.51% zinc.展开更多
Vuggy reservoirs are the most common, albeit important heterogeneous carbonate reservoirs in China. However, saturation calculations using logging data are not well developed, whereas Archie method is more common. In ...Vuggy reservoirs are the most common, albeit important heterogeneous carbonate reservoirs in China. However, saturation calculations using logging data are not well developed, whereas Archie method is more common. In this study, electrical conduction in a vuggy reservoir is theoretically analyzed to establish a new saturation equation for vuggy reservoirs. We found that vugs have a greater effect on saturation than resistivity, which causes inflection in the rock-electricity curve. Using single-variable exPeriments, we evaluated the effects of rug size, vug number, and vug distribution on the rock-electricity relation. Based on the general saturation model, a saturation equation for vuggy reservoirs is derived, and the physical significance of the equation parameters is discussed based on the seepage-electricity similarity. The equation parameters depend on the pore structure, and vugs and matrix pore size distribution. Furthermore, a method for calculating the equation parameters is proposed, which uses nuclear magnetic resonance (NMR) data to calculate the capillary pressure curve. Field application of the proposed equation and parameter derivation method shows good match between calculated and experimental results, with an average absolute error of 5.8%.展开更多
Using the 3-year observational data from ChinaFlux (Chinese Terrestrial Ecosystem Flux Research Network), we studied the gas regulation flux dynamics and cumulative process of gas regulation value in Qianyanzhou mid...Using the 3-year observational data from ChinaFlux (Chinese Terrestrial Ecosystem Flux Research Network), we studied the gas regulation flux dynamics and cumulative process of gas regulation value in Qianyanzhou middle subtropical plantation (QYF) and Changbai Mountain temperate mixed forest (CBF). The gas regulation service was differentiated into vegetation gas regulation service and net ecosystem gas regulation service. Carbon tax approach, reforestation cost approach and industrial oxygen approach were employed to calculate gas regulation value. Results show that there was significant seasonal variation in vegetation gas regulation flux. Daily CO2 uptake fluxes averaged 82.00 kg·ha^-·d^-1 and 59.37 kg·ha^-·d^-1 and the corresponding 02 emission fluxes were 59.65 kg·ha^-·d^-1 and 43.19 kg·ha^-·d^-1 for QYF and CBF, respectively. The cumulative curves of vegetation gas regulation value always followed a sigmoid shape, and the annual gas regulation value produced by vegetation was RMB 14342.69 yuan·ha^-1 and RMB 10384.18 yuan·ha^-1 for both QYF and CBF, respectively. In terms of monthly net ecosystem gas regulation service, QYF appeared as a CO2 sink and O2 source for the whole year, while CBF appeared to be a CO2 sink and O2 source mainly in the period between May and September. The cumulative curves of net ecosystem gas regulation value presented a sigmoid ("S") shape for QYF, while a unimodal type curve for CBF. The annual net ecosystem gas regulation value was 8470.52 yuan·ha^-1 and 5091.98yuan·ha^-1 for QYF and CBF, respectively. The economic value of both the vegetation gas regulation service and net ecosystem gas regulation service were mainly produced between May and October.展开更多
The pharmacokinetics of morphine sulphate was studied in 10 Chinese healthy volunteers after a single oral dose. Blood samples were collected before and after administration of controlled release tablets (CRMS, 30 mg)...The pharmacokinetics of morphine sulphate was studied in 10 Chinese healthy volunteers after a single oral dose. Blood samples were collected before and after administration of controlled release tablets (CRMS, 30 mg) and immediate release tablets (IRMS, 20 mg). The plasma concentration of morphine was determined by GC MS. The pharmacokinetic parameters of controlled release tablets and immediate release tablets were calculated∶ C max was 19.38±3.80 and 21.27±6.21 ng/ml, t max was 2.36 ±0.37 h and 0.56±0.16 h, t 1/2β was 3.53±0.87 and 3.03±0.74 h, AUC was 145.15±17.65 and 93.08±16.65 ng/ml, respectively. The steady state plasma concentration of morphine sulphate in cancer patients after multiple doses was achieved, C max of CRMS and IRMS was 27.43±0.33 ng/ml and 22.68±0.16 ng/ml, C min of CRMS and IRMS was 19.45±1.44 ng/ml and 18.14±0.49 ng/ml, respectively.展开更多
Difficulties with soft coal seams having a high gas content and high stress levels can be addressed by a technology of pressure relief and permeability increase.Slotting the seam by auxiliary drilling with a water jet...Difficulties with soft coal seams having a high gas content and high stress levels can be addressed by a technology of pressure relief and permeability increase.Slotting the seam by auxiliary drilling with a water jet that breaks the coal and slots the coal seam during the process of retreat drilling achieves pressure relief and permeability increase.Improved efficiency of gas extraction from a field test,high gas coal seam was observed.Investigating the theory of pressure relief and permeability increase required analyzing the characteristics of the double power slotting process and the effects of coal pressure relief and permeability increase.The influence of confining pressure on coal physical properties was examined by using FLAC3D software code to simulate changes of coal stress within the tool destruction area.The double power joint drilling method was modeled.Field experiments were performed and the effects are analyzed.This research shows that there is an ''islanding effect'' in front of the joint double power drill and slotting equipment.The failure strength of the coal seam is substantially reduced within the tool destruction area.Drilling depths are increased by 72% and the diameter of the borehole is increased by 30%.The amount of powdered coal extracted from the drill head increases by 17 times when using the new method.A 30 day total flow measurement from the double power drilled and slotted bores showed that gas extraction increased by 1.3 times compared to the standard drilled bores.Gas concentrations increased from 30% to 60% and were more stable so the overall extraction efficiency increased by a factor of two times.展开更多
The prototypical reaction of F+HD→DF+H was investigated at collision energies from 3.03 meV to 17.97 meV using a crossed molecular beam apparatus with multichannel Rydberg tagging time-of-flight detection.Significant...The prototypical reaction of F+HD→DF+H was investigated at collision energies from 3.03 meV to 17.97 meV using a crossed molecular beam apparatus with multichannel Rydberg tagging time-of-flight detection.Significant contributions from both the BornOppenheimer(BO)forbidden reaction F^(*)(^(2)P_(1/2))+HD→DF+H and the BO-allowed reaction F(^(2)P_(3/2))+HD→DF+H were observed.In the backward scattering direction,the contribution from the BO-forbidden reaction F^(*)(^(2)P_(1/2))+HD was found to be considerably greater than the BO-allowed reaction F(^(2)P_(3/2))+HD,indicating the non-adiabatic effects play an important role in the dynamics of the title reaction at low collision energies.Collision-energy dependence of differential cross sections(DCSs)in the backward scattering direction was found to be monotonously decreased as the collision energy decreases,which does not support the existence of resonance states in this energy range.DCSs of both BO-allowed and BO-forbidden reactions were measured at seven collision energies from 3.03 meV to 17.97 meV.It is quite unexpected that the angular distribution gradually shifts from backward to sideway as the collision energy decreases from 17.97 meV to 3.03 meV,suggesting some unknown mechanisms may exist at low collision energies.展开更多
This research explores media users' cognition of "time" and "space" across different media platforms, and conducts a comparison among media genres including mass media and intemet media based on user's interacti...This research explores media users' cognition of "time" and "space" across different media platforms, and conducts a comparison among media genres including mass media and intemet media based on user's interactivities. Especially, this research focused on the internet's space and time perception based on communication genres such as e-mail, Blogs, portals, news-media, e-commerce, and social media (SNS). The research adopted two theories (construal level theory of time and space). The time related theory is "temporal distance theory". The space related theory is "media space". The research is designed to measure user's perception of interactivity, time-construal level and its media space cognition while using the media. There are two independent variables: Interactivities (contents, user, and media levels) and user involvement (CMC-user vs. user, HCI-user vs. media); there are two dependent variables: Cognition of spatial and temporal levels. This research also seeks the associated variables relationship among those variables through the structural equation model (SEM). The 307 data was collected and analyzed to test the research question. The results show that the dimension of the media side's interactivity affected media's usage time and space perception. There are 2 ~ 2 factors variables to affect time and space. One is human and media interaction (HC1) and human to human communication (CMC); the other is traditional mass media (one-way communication) and interuet media (two-ways communication). The results prove the user's perception for media time and space is based on the levels of interactivity. The levels of interactivities depend on media usage: one-one, one-many, synchronous, asynchronous, interpersonal, and social network communication. Online media provides greater social space; while traditional media tends toward para-space perception. On the other hand, the users' time cognitions between online media are different such as fixed time versus cyber-time.展开更多
In 2000, the interpretation of the specific application of law on the trial of traffic accident criminal cases was issued by the Supreme People' s court. The second article and the fourth article in the judicial inte...In 2000, the interpretation of the specific application of law on the trial of traffic accident criminal cases was issued by the Supreme People' s court. The second article and the fourth article in the judicial interpretation take the "no ability of the amount of compensation" as conviction and aggravated punishment standard after the traffic accident, causing the academic community fierce controversy. This article briefly states the publishing background, applicable conditions, defects and its positive significance of the two provisions. This paper nresents the immature modification suggestions for the two nrovisions.展开更多
Ryanodine receptors(Ry Rs) are the calcium release channels of sarcoplasmic reticulum(SR) that provide the majority of calcium ions(Ca2+) necessary to induce contraction of cardiac and skeletal muscle cells.In their i...Ryanodine receptors(Ry Rs) are the calcium release channels of sarcoplasmic reticulum(SR) that provide the majority of calcium ions(Ca2+) necessary to induce contraction of cardiac and skeletal muscle cells.In their intracellular environment,Ry R channels are regulated by a variety of cytosolic and luminal factors so that their output signal(Ca2+) induces finely-graded cell contraction without igniting cellular processes that may lead to aberrant electrical activity(ventricular arrhythmias) or cellular remodeling.The importance of Ry R dysfunction has been recently highlighted with the demonstration that point mutations in RYR2,the gene encoding for the cardiac isoform of the Ry R(Ry R2),are associated with catecholaminergic polymorphic ventricular tachycardia(CPVT),an arrhythmogenic syndrome characterized by the development of adrenergically-mediated ventricular tachycardia in individuals with an apparently normal heart.Here we summarize the state of the field in regards to the main arrhythmogenic mechanisms triggered by Ry R2 channels harboring mutations linked to CPVT.Most CPVT mutations characterized to date endow Ry R2 channels with a gain of function,resulting in hyperactive channels that release Ca2+ spontaneously,especially during diastole.The spontaneous Ca2+ release is extruded by the electrogenic Na+/Ca2+ exchanger,which depolarizes the external membrane(delayed afterdepolarization or DAD) and may trigger untimely action potentials.However,a rare set of CPVT mutations yield Ry R2 channels that are intrinsically hypo-active and hypo-responsive to stimuli,and it is unclear whether these channels release Ca2+ spontaneously during diastole.We discuss novel cellular mechanisms that appear more suitable to explain ventricular arrhythmias due to Ry R2 loss-of-function mutations.展开更多
Particle size, porosity, and the initial phosphorus concentration in sediments are the main factors affecting phosphorus release flux through the sediment-water interface. Sediments can be physically divided to muddy ...Particle size, porosity, and the initial phosphorus concentration in sediments are the main factors affecting phosphorus release flux through the sediment-water interface. Sediments can be physically divided to muddy and sandy matters, and the adsorption-desorption capacity of sediment with phosphorus depends on particle size. According to phosphorus adsorption-desorption experiments, phosphorus sorption capacity of the sediment decreases with the increase of particle dimension. But among the size-similar particles, sediment with a bigger particle size has the larger initial phosphorus release rate. In terms of muddy and sandy sediments, there are inversely proportional relationships between the release rate and the flux. Due to the contact of surface sediment and the overlying water, the release flux from the sediment is either from direct desorption of surface sediment layer or from the diffusion of pore water in the sediment layer, which is mainly determined by sediment particle size and porosity. Generally, static phosphorus release process may include two stages: the first is the initial release. As for coarse particles, phosphorus is desorbed from surface sediment. And for fine particles, phosphorus concentration in water often decreases, mainly from pore water by the molecular diffusion. During the second stage, pore water flows faster in coarse sediment, and phosphorus is easy to desorb from the surface of the particles as diffusion dominates. For the smaller liquid-solid ratio of fine particles and the larger amount of phosphorus adsorption, the release flux from pore water due to diffusion is very small with longer sorption duration.展开更多
Correlations of fire-induced temperature have been reviewed and revisited.The impact of XY factors,i.e.,the relative locations of the fire source and vent,on temperature models of ceiling-vented compartments could be ...Correlations of fire-induced temperature have been reviewed and revisited.The impact of XY factors,i.e.,the relative locations of the fire source and vent,on temperature models of ceiling-vented compartments could be reflected by the exponents of the two dimensionless terms which represent the ratio of the total energy to energy released through the ceiling vent,and the ratio of the energy lost through the walls to the energy released through the ceiling vent.For fires not located directly below the ceiling vent,the temperature rise was proportional to two thirds of the power of the heat release rate,while for fires immediately beneath this vent,the temperature rise was proportional to four thirds the power of the heat release rate,and was inversely proportional to one sixth the power of the ceiling vent size.展开更多
基金Project (2007BAC03A11-07) supported by the Ministry of Science and Technology of ChinaProject (KZCX3-SW-437) supported by the Chinese Academy of SciencesProjects (41040014,40571008) supported by the National Natural Science Foundation of China
文摘Nonferrous mining activities are some of the largest sources of heavy metals emissions into the environment and China is one of the largest producers and consumers of lead and zinc in the world.The cumulative productions and emissions of lead and zinc from mining-related activities in China were estimated.Up to 2007,the cumulative productions of lead and zinc in China were estimated to be about 6.69 and 12.59 Mt,respectively;and about 1.62 Mt lead and 3.32 Mt zinc emitted into the ambient environment during the mining,processing and smelting activities,representing 24.39% and 26.36% cumulative production,respectively.Among these three types of mining-related activities,mineral processing contributes the most to the total emission of 50.67% lead and 45.51% zinc.
基金supported by the National S&T Major Special Project(No.2011ZX05020-008)
文摘Vuggy reservoirs are the most common, albeit important heterogeneous carbonate reservoirs in China. However, saturation calculations using logging data are not well developed, whereas Archie method is more common. In this study, electrical conduction in a vuggy reservoir is theoretically analyzed to establish a new saturation equation for vuggy reservoirs. We found that vugs have a greater effect on saturation than resistivity, which causes inflection in the rock-electricity curve. Using single-variable exPeriments, we evaluated the effects of rug size, vug number, and vug distribution on the rock-electricity relation. Based on the general saturation model, a saturation equation for vuggy reservoirs is derived, and the physical significance of the equation parameters is discussed based on the seepage-electricity similarity. The equation parameters depend on the pore structure, and vugs and matrix pore size distribution. Furthermore, a method for calculating the equation parameters is proposed, which uses nuclear magnetic resonance (NMR) data to calculate the capillary pressure curve. Field application of the proposed equation and parameter derivation method shows good match between calculated and experimental results, with an average absolute error of 5.8%.
基金Chinese Terrestrial Ecosystem Flux Observational Research Network(ChinaFlux) for providing the observational data
文摘Using the 3-year observational data from ChinaFlux (Chinese Terrestrial Ecosystem Flux Research Network), we studied the gas regulation flux dynamics and cumulative process of gas regulation value in Qianyanzhou middle subtropical plantation (QYF) and Changbai Mountain temperate mixed forest (CBF). The gas regulation service was differentiated into vegetation gas regulation service and net ecosystem gas regulation service. Carbon tax approach, reforestation cost approach and industrial oxygen approach were employed to calculate gas regulation value. Results show that there was significant seasonal variation in vegetation gas regulation flux. Daily CO2 uptake fluxes averaged 82.00 kg·ha^-·d^-1 and 59.37 kg·ha^-·d^-1 and the corresponding 02 emission fluxes were 59.65 kg·ha^-·d^-1 and 43.19 kg·ha^-·d^-1 for QYF and CBF, respectively. The cumulative curves of vegetation gas regulation value always followed a sigmoid shape, and the annual gas regulation value produced by vegetation was RMB 14342.69 yuan·ha^-1 and RMB 10384.18 yuan·ha^-1 for both QYF and CBF, respectively. In terms of monthly net ecosystem gas regulation service, QYF appeared as a CO2 sink and O2 source for the whole year, while CBF appeared to be a CO2 sink and O2 source mainly in the period between May and September. The cumulative curves of net ecosystem gas regulation value presented a sigmoid ("S") shape for QYF, while a unimodal type curve for CBF. The annual net ecosystem gas regulation value was 8470.52 yuan·ha^-1 and 5091.98yuan·ha^-1 for QYF and CBF, respectively. The economic value of both the vegetation gas regulation service and net ecosystem gas regulation service were mainly produced between May and October.
文摘The pharmacokinetics of morphine sulphate was studied in 10 Chinese healthy volunteers after a single oral dose. Blood samples were collected before and after administration of controlled release tablets (CRMS, 30 mg) and immediate release tablets (IRMS, 20 mg). The plasma concentration of morphine was determined by GC MS. The pharmacokinetic parameters of controlled release tablets and immediate release tablets were calculated∶ C max was 19.38±3.80 and 21.27±6.21 ng/ml, t max was 2.36 ±0.37 h and 0.56±0.16 h, t 1/2β was 3.53±0.87 and 3.03±0.74 h, AUC was 145.15±17.65 and 93.08±16.65 ng/ml, respectively. The steady state plasma concentration of morphine sulphate in cancer patients after multiple doses was achieved, C max of CRMS and IRMS was 27.43±0.33 ng/ml and 22.68±0.16 ng/ml, C min of CRMS and IRMS was 19.45±1.44 ng/ml and 18.14±0.49 ng/ml, respectively.
基金supports provided by the National Key Basic Research and Development Program of China (No. 2011CB201205)the National Natural Science Foundation of China (No. 51074161)the Independent research of State Key Laboratory of Coal Resources and Mine Safety of China University of Mining & Technology (No. SKLCRSM08X03)
文摘Difficulties with soft coal seams having a high gas content and high stress levels can be addressed by a technology of pressure relief and permeability increase.Slotting the seam by auxiliary drilling with a water jet that breaks the coal and slots the coal seam during the process of retreat drilling achieves pressure relief and permeability increase.Improved efficiency of gas extraction from a field test,high gas coal seam was observed.Investigating the theory of pressure relief and permeability increase required analyzing the characteristics of the double power slotting process and the effects of coal pressure relief and permeability increase.The influence of confining pressure on coal physical properties was examined by using FLAC3D software code to simulate changes of coal stress within the tool destruction area.The double power joint drilling method was modeled.Field experiments were performed and the effects are analyzed.This research shows that there is an ''islanding effect'' in front of the joint double power drill and slotting equipment.The failure strength of the coal seam is substantially reduced within the tool destruction area.Drilling depths are increased by 72% and the diameter of the borehole is increased by 30%.The amount of powdered coal extracted from the drill head increases by 17 times when using the new method.A 30 day total flow measurement from the double power drilled and slotted bores showed that gas extraction increased by 1.3 times compared to the standard drilled bores.Gas concentrations increased from 30% to 60% and were more stable so the overall extraction efficiency increased by a factor of two times.
基金supported by the National Natural Science Foundation of China(No.21822305,No.21688102,No.22003067)the Chinese Academy of Sciences(No.XDB17000000)。
文摘The prototypical reaction of F+HD→DF+H was investigated at collision energies from 3.03 meV to 17.97 meV using a crossed molecular beam apparatus with multichannel Rydberg tagging time-of-flight detection.Significant contributions from both the BornOppenheimer(BO)forbidden reaction F^(*)(^(2)P_(1/2))+HD→DF+H and the BO-allowed reaction F(^(2)P_(3/2))+HD→DF+H were observed.In the backward scattering direction,the contribution from the BO-forbidden reaction F^(*)(^(2)P_(1/2))+HD was found to be considerably greater than the BO-allowed reaction F(^(2)P_(3/2))+HD,indicating the non-adiabatic effects play an important role in the dynamics of the title reaction at low collision energies.Collision-energy dependence of differential cross sections(DCSs)in the backward scattering direction was found to be monotonously decreased as the collision energy decreases,which does not support the existence of resonance states in this energy range.DCSs of both BO-allowed and BO-forbidden reactions were measured at seven collision energies from 3.03 meV to 17.97 meV.It is quite unexpected that the angular distribution gradually shifts from backward to sideway as the collision energy decreases from 17.97 meV to 3.03 meV,suggesting some unknown mechanisms may exist at low collision energies.
文摘This research explores media users' cognition of "time" and "space" across different media platforms, and conducts a comparison among media genres including mass media and intemet media based on user's interactivities. Especially, this research focused on the internet's space and time perception based on communication genres such as e-mail, Blogs, portals, news-media, e-commerce, and social media (SNS). The research adopted two theories (construal level theory of time and space). The time related theory is "temporal distance theory". The space related theory is "media space". The research is designed to measure user's perception of interactivity, time-construal level and its media space cognition while using the media. There are two independent variables: Interactivities (contents, user, and media levels) and user involvement (CMC-user vs. user, HCI-user vs. media); there are two dependent variables: Cognition of spatial and temporal levels. This research also seeks the associated variables relationship among those variables through the structural equation model (SEM). The 307 data was collected and analyzed to test the research question. The results show that the dimension of the media side's interactivity affected media's usage time and space perception. There are 2 ~ 2 factors variables to affect time and space. One is human and media interaction (HC1) and human to human communication (CMC); the other is traditional mass media (one-way communication) and interuet media (two-ways communication). The results prove the user's perception for media time and space is based on the levels of interactivity. The levels of interactivities depend on media usage: one-one, one-many, synchronous, asynchronous, interpersonal, and social network communication. Online media provides greater social space; while traditional media tends toward para-space perception. On the other hand, the users' time cognitions between online media are different such as fixed time versus cyber-time.
文摘In 2000, the interpretation of the specific application of law on the trial of traffic accident criminal cases was issued by the Supreme People' s court. The second article and the fourth article in the judicial interpretation take the "no ability of the amount of compensation" as conviction and aggravated punishment standard after the traffic accident, causing the academic community fierce controversy. This article briefly states the publishing background, applicable conditions, defects and its positive significance of the two provisions. This paper nresents the immature modification suggestions for the two nrovisions.
基金supported by grants from the US National Institutes of Health(RO1-HL55438,PO1-HL094291,and RO1-108175 to HHV)a recipient of a fellowship from the Panamanian Ministry of Science
文摘Ryanodine receptors(Ry Rs) are the calcium release channels of sarcoplasmic reticulum(SR) that provide the majority of calcium ions(Ca2+) necessary to induce contraction of cardiac and skeletal muscle cells.In their intracellular environment,Ry R channels are regulated by a variety of cytosolic and luminal factors so that their output signal(Ca2+) induces finely-graded cell contraction without igniting cellular processes that may lead to aberrant electrical activity(ventricular arrhythmias) or cellular remodeling.The importance of Ry R dysfunction has been recently highlighted with the demonstration that point mutations in RYR2,the gene encoding for the cardiac isoform of the Ry R(Ry R2),are associated with catecholaminergic polymorphic ventricular tachycardia(CPVT),an arrhythmogenic syndrome characterized by the development of adrenergically-mediated ventricular tachycardia in individuals with an apparently normal heart.Here we summarize the state of the field in regards to the main arrhythmogenic mechanisms triggered by Ry R2 channels harboring mutations linked to CPVT.Most CPVT mutations characterized to date endow Ry R2 channels with a gain of function,resulting in hyperactive channels that release Ca2+ spontaneously,especially during diastole.The spontaneous Ca2+ release is extruded by the electrogenic Na+/Ca2+ exchanger,which depolarizes the external membrane(delayed afterdepolarization or DAD) and may trigger untimely action potentials.However,a rare set of CPVT mutations yield Ry R2 channels that are intrinsically hypo-active and hypo-responsive to stimuli,and it is unclear whether these channels release Ca2+ spontaneously during diastole.We discuss novel cellular mechanisms that appear more suitable to explain ventricular arrhythmias due to Ry R2 loss-of-function mutations.
基金supported by the National Natural Science Foundation of China(Grant No.10972134)the State Key Program of National Natural Science of China(Grant No.11032007)The Shanghai Program for Innovative Research Team in Universities is also acknowledged
文摘Particle size, porosity, and the initial phosphorus concentration in sediments are the main factors affecting phosphorus release flux through the sediment-water interface. Sediments can be physically divided to muddy and sandy matters, and the adsorption-desorption capacity of sediment with phosphorus depends on particle size. According to phosphorus adsorption-desorption experiments, phosphorus sorption capacity of the sediment decreases with the increase of particle dimension. But among the size-similar particles, sediment with a bigger particle size has the larger initial phosphorus release rate. In terms of muddy and sandy sediments, there are inversely proportional relationships between the release rate and the flux. Due to the contact of surface sediment and the overlying water, the release flux from the sediment is either from direct desorption of surface sediment layer or from the diffusion of pore water in the sediment layer, which is mainly determined by sediment particle size and porosity. Generally, static phosphorus release process may include two stages: the first is the initial release. As for coarse particles, phosphorus is desorbed from surface sediment. And for fine particles, phosphorus concentration in water often decreases, mainly from pore water by the molecular diffusion. During the second stage, pore water flows faster in coarse sediment, and phosphorus is easy to desorb from the surface of the particles as diffusion dominates. For the smaller liquid-solid ratio of fine particles and the larger amount of phosphorus adsorption, the release flux from pore water due to diffusion is very small with longer sorption duration.
基金supported by the Anhui Provincial Natural Science Foundation(1408085MKL94)
文摘Correlations of fire-induced temperature have been reviewed and revisited.The impact of XY factors,i.e.,the relative locations of the fire source and vent,on temperature models of ceiling-vented compartments could be reflected by the exponents of the two dimensionless terms which represent the ratio of the total energy to energy released through the ceiling vent,and the ratio of the energy lost through the walls to the energy released through the ceiling vent.For fires not located directly below the ceiling vent,the temperature rise was proportional to two thirds of the power of the heat release rate,while for fires immediately beneath this vent,the temperature rise was proportional to four thirds the power of the heat release rate,and was inversely proportional to one sixth the power of the ceiling vent size.