Complex hydrocultural conditions in the estuary affect the migration and transformation of mercury.Using two voyages in July and October 2018,Dissolved Gaseous Mercury(DGM)and Reactive Mercury(RHg)were determined to e...Complex hydrocultural conditions in the estuary affect the migration and transformation of mercury.Using two voyages in July and October 2018,Dissolved Gaseous Mercury(DGM)and Reactive Mercury(RHg)were determined to explore the source,transformation and influence of DGM content in the adjacent waters of Yangtze River Estuary in summer and autumn.The results showed the contents of DGM and RHg in summer were higher than those in autumn,and both of them were higher than those in open sea.In summer and autumn,the Yangtze River brought a higher concentration of DGM,and different flow direction and runoff resulted in differences in the high value region of the surface.The emergence of low-oxygen zones in summer was conducive to the production of DGM.In autumn,windy weather allowed seawater disturbances to promote the release of mercury from the underlying sediments,especially in shallow sea in northwest.RHg showed a higher concentration in the offshore than in the open sea in summer,but there was no such trend in autumn,reflecting the influence of less runoff input.DGM is the main product of RHg reduction,and there was a significant positive correlation between DGM and RHg in summer(r=0.356,P<0.05),while the correlation between DGM and RHg was not significant in autumn due to the influence of light intensity,wind speed and nutrients.The exchange flux of mercury in the adjacent waters of the Yangtze River Estuary was higher than that in the open sea.There was no significant difference of the release flux of mercury in summer and autumn.This article highlighted that the input of mercury from the Yangtze River runoff promotes the release of mercury in seawater,and the hypoxic zone caused by eutrophication is conducive to the production of DGM.展开更多
Theδ18O of ice core enclosed gaseous oxygen(δ18Obub)has been widely used for climate reconstruction in polar regions.Yet,less is known about its climatic implication in the mountainous glaciers as the lack of contin...Theδ18O of ice core enclosed gaseous oxygen(δ18Obub)has been widely used for climate reconstruction in polar regions.Yet,less is known about its climatic implication in the mountainous glaciers as the lack of continuous record.Here,we present a long-term,continuousδ18Obub record from the Tanggula glacier in the central Tibetan Plateau(TP).Based on comparisons of its variation with regional climate and glacier changes,we found that there was a good correlation between the variation of theδ18Obub in this alpine ice core and the accumulation and melting of this glacier.The more developed the firn layer on glacier surface,the more positive theδ18Obub.Conversely,the more intense the glacier melting,the more negative theδ18Obub.Combined with the chronology of ice core enclosed gases,the glacier variations since the late Holocene in the central TP were reconstructed.The result showed that there were four accumulation and three deficit periods of glaciers in this region.The strongest glacier accumulation period was 1610-300 B.C.,which corresponds to the Neoglaciation.The most significant melting period was the last 100 years,which corresponds to the recent global warming.The Medieval Warm Period was relatively significant in the central TP.However,during the Little Ice Age,there was no significant glacier accumulation in the central TP,and even short deficit events occurred.Comparisons of the late Holocene glacier variation in the central TP with glacier and climate variations in the TP and the Northern Hemisphere showed that it was closely related to the North Atlantic Oscillation.展开更多
A method combining theoretical analysis with experiment is adopted and the flowing process of Ti-48A1-2Cr-2Nb alloy melt poured in a permanent mould during the centrifugal casting process has been analyzed. A mathemat...A method combining theoretical analysis with experiment is adopted and the flowing process of Ti-48A1-2Cr-2Nb alloy melt poured in a permanent mould during the centrifugal casting process has been analyzed. A mathematical model of the filling process is established and the forming mechanism of internal gaseous defect is summarized. The results of calculation show that the melt fills the mould with varying cross-section area and inclined angle. The filling speed of the cross-section is a function of filling time. The cross-section area is directly proportional to the filling speed and the inclined angle is inversely proportional to the filling speed at a given rotating speed of the platform. Both of them changes more obvious near the mould entrance. The gaseous defect can be formed in several ways and the centrifugal field has an important influence on the formation of the defect. In addition, the filling process in centrifugal field has been verified by wax experiments and the theoretical analysis are consistent with experimental results.展开更多
The paper presented the results regarding the decomposition of gaseous CF<sub>2</sub>ClB<sub>r</sub> bycold plasma method.After two minutes discharge,the maximum decomposition rate of 2660 PaCF...The paper presented the results regarding the decomposition of gaseous CF<sub>2</sub>ClB<sub>r</sub> bycold plasma method.After two minutes discharge,the maximum decomposition rate of 2660 PaCF<sub>2</sub>ClB<sub>r</sub> pure and 2660 Pa CF<sub>2</sub>ClBr plus 7980 Pa O<sub>2</sub> reached 60% and 80%,respectively.The pa-per also studied the cold plasma gas phase chemistry reaction mechanism of CF<sub>2</sub>ClBr at low pres-sure,and the pressure effects of CF<sub>2</sub>ClBr and added gas（He,N<sub>2</sub>,O<sub>2</sub> and dry air）on the CF<sub>2</sub>ClBrdecomposition respectively by cold plasma method.These studies will be helpful to application ofcold plasma method in the treatment of hazardous gaseous wastes.展开更多
BACKGROUND: Hepatic ischemia-reperfusion injury is one of the major problems in liver transplantation. This study aimed to investigate the possible improvement of aerobic metabolism of ischemic donor livers through sy...BACKGROUND: Hepatic ischemia-reperfusion injury is one of the major problems in liver transplantation. This study aimed to investigate the possible improvement of aerobic metabolism of ischemic donor livers through systemic persufflation with gaseous oxygen in rinse solution. METHODS: Thirty rats were randomly divided into 3 groups. In group A (control, n = 10), the livers were perfused with 4 ℃ lactic acid ringer’s solution through the can-nulated portal vein for 25 minutes soon after warm ischemia for 30 minutes. In group B (n =10), the livers were treated the same way as in group A except for addition of gaseous oxygen in the rinse solution. In group C (n =10), the livers were treated similarly as in group B except for addition of superoxide dismutase (SOD) in the rinse solution. RESULTS: In group B, the malondialdehyde(MDA)levels in hepatic tissues after perfusion were significantly increased (P【 0. 01), whereas the SOD levels were markedly decreased (P 【0.01). After combined use with antioxidant in group C, the levels of MDA and SOD in hepatic tissues after perfusion recovered significantly (P【0.01). CONCLUSION: Perfusion by gaseous oxygen persufQation in combination with antioxidative agents is promising for resuscitating the ischemically altered livers for successful transplantation.展开更多
This work proposed to use the ionic liquid [EMIM][BF_4] as absorbent for the absorption of gaseous acetic acid. The feasibility of this technology was investigated from molecular level to industrial scale. The acetic ...This work proposed to use the ionic liquid [EMIM][BF_4] as absorbent for the absorption of gaseous acetic acid. The feasibility of this technology was investigated from molecular level to industrial scale. The acetic acid absorption experiment was carried out using [EMIM][BF_4],and the removal ratio of acetic acid in the gas product can achieve 88.6% at 20C under atmospheric pressure at the laboratory scale. Based on the experimental results, a reliable strict equilibrium phase model embedding the parameters of the UNIFAC model was established. On this basis, the conceptual process design and optimization of acetic acid removal by [EMIM][BF_4] at an industrial scale was done, and the most suitable design and operation parameters were obtained. For a further step, the binding energy between [EMIM][BF_4] and acetic acid was calculated to give some insights into the separation mechanism, and the results indicate that the interaction between acetic acid and IL is much stronger than that between nitrogen and IL. Moreover, hydrogen bond can be formed between the cation-acetic acid as well as the anion-acetic acid.展开更多
ABSTRACT The Raman intensitics of gas molecules were found to be enormously enhanced inthe presence of Hg-microdroplets.The enhancement factor for the molecules studied was foundto be over 20.
Both experimental and numerical studies were presented on the flow field characteristics in the process of gaseous jet impinging on liquid–water column. The effects of the impinging process on the working performance...Both experimental and numerical studies were presented on the flow field characteristics in the process of gaseous jet impinging on liquid–water column. The effects of the impinging process on the working performance of rocket engine were also analyzed. The experimental results showed that the liquid–water had better flame and smoke dissipation effect in the process of gaseous jet impinging on liquid–water column. However, the interaction between the gaseous jet and the liquid–water column resulted in two pressure oscillations with large amplitude appearing in the combustion chamber of the rocket engine with instantaneous pressure increased by 17.73% and 17.93%, respectively. To analyze the phenomena, a new computational method was proposed by coupling the governing equations of the MIXTURE model with the phase change equations of water and the combustion equation of propellant. Numerical simulations were carried out on the generation of gas, the accelerate gas flow, and the mutual interaction between gaseous jet and liquid–water column.Numerical simulations showed that a cavity would be formed in the liquid–water column when gaseous jet impinged on the liquid–water column. The development speed of the cavity increased obviously after each pressure oscillation. In the initial stage of impingement, the gaseous jet was blocked due to the inertia effect of high-density water, and a large amount of gas gathered in the area between the nozzle throat and the gas–liquid interface. The shock wave was formed in the nozzle expansion section. Under the dual action of the reverse pressure wave and the continuously ejected high-temperature gas upstream, the shock wave moved repeatedly in the nozzle expansion section, which led to the flow of gas in the combustion chamber being blocked, released, re-blocked, and re-released. This was also the main reason for the pressure oscillations in the combustion chamber.展开更多
BaTiO3∶Mn0.006Smx(x=0.001, 0.002, 0.003, 0.004, 0.006 respectively) ceramics were prepared by using sol-gel method and their resistivities at different temperatures were measured. The results showed that Mn element m...BaTiO3∶Mn0.006Smx(x=0.001, 0.002, 0.003, 0.004, 0.006 respectively) ceramics were prepared by using sol-gel method and their resistivities at different temperatures were measured. The results showed that Mn element may enhance the PTC characteristics of BaTiO3 ceramics. But the doped Mn element deteriorated the room temperature resistivities of the modified BaTiO3 ceramics which were greater than 105 Ω·m. Then, rare earth element Sm was penetrated into BaTiO3∶Mn0.06Smx ceramics in gaseous state, which largely decreased the room temperature resistivity to 3.20 Ω·m, and appeared as a NTC effect instead of PTC effect. The forming mechanism of NTC effect was explored through analyses of SEM and electric properties of Sm-penetrated BaTiO3∶Mn0.006Smx ceramics.展开更多
The fluorescence of gaseous CS_2 was studied by laser - induced fluorescence (LIF) method. Aworking curve of gaseous CS_2 was obtained and the detection limit was less than 1 ppm. The time - resolvedfluorescence emiss...The fluorescence of gaseous CS_2 was studied by laser - induced fluorescence (LIF) method. Aworking curve of gaseous CS_2 was obtained and the detection limit was less than 1 ppm. The time - resolvedfluorescence emission spectrum of CS_2 vapor was recorde展开更多
From 28 March to 17 April, 2018, different forms of mercury(Hg) in the Yellow Sea and Bohai Sea were measured to study the influencing factors on the distribution and transformation of Hg in spring using a shared crui...From 28 March to 17 April, 2018, different forms of mercury(Hg) in the Yellow Sea and Bohai Sea were measured to study the influencing factors on the distribution and transformation of Hg in spring using a shared cruise. The mean concentration of dissolved gaseous mercury(DGM) in the surface water of the Yellow and Bohai Seas was(44.3 ± 43.9) pg/L, which was close to that in mid-latitude oceans and deep seas. The ratio of DGM to THg(total mercury) was lower than in the oceans and in the Yellow and Bohai Seas in summer or fall. DGM concentrations in surface water were highest in the central part of the South Yellow Sea and were higher than those in the Bohai Sea, and their spatial distributions were consistent with RHg(reactive mercury). DGM and RHg correlated positively with water temperature in surface seawater(r = 0.506, P < 0.01;r = 0.278, P < 0.05). The concentrations of both DGM and RHg in surface water were controlled by solar radiation and water temperature. Foggy weather did not benefit the production of DGM and RHg. DGM in the bottom seawater was mainly affected by Dissolved Oxygen and water temperature(r =-0.366, P < 0.01;r = 0.331, P < 0.01), produced mainly by anaerobic reactions of the bottom seawater and sediment microorganisms. The bottom DGM concentrations in the Yellow and Bohai Seas were the highest, and DGM produced in bottom seawater and sediment plays a more important role than the surface water in spring. The concentrations of DGM and RHg in the surface and bottom water in the South Yellow Sea were all higher than those in the middle layer. Vertical variations in the North Yellow Sea and the Bohai Sea were small. The production and distribution of DGM and RHg were influenced by differences of latitude and by the Yellow Sea warm current in spring.展开更多
To infer the internal equilibrium structure of a gaseous planet, especially the equation of state(EOS) and size of its inner core,requires accurate determination of lower-order zonal gravitational coefficients. Modeli...To infer the internal equilibrium structure of a gaseous planet, especially the equation of state(EOS) and size of its inner core,requires accurate determination of lower-order zonal gravitational coefficients. Modeling of the gravitational signature associated with deep zonal circulation depends critically upon reliable subtraction of the dynamical components from totally derived gravitational coefficients. In the era of the Juno mission and the Grand Finale phase of the Cassini mission, it is timely and necessary to revisit and examine the so-called ‘Thermal Wind Equation(TWE)’, which has been extensively utilized to diagnose the dynamical parts of the gravitational fields measured by the two spacecrafts. TWE treats as negligible a few terms in the full equation of balance. However, the self-gravitational anomaly of the distorted fluid, unlike oblateness effects of solid-body rotation, is not a priori minor and thus should not be neglected in the name of approximation. Another equation, the ‘Thermal Gravitational Wind Equation(TGWE)’, includes this important additional term;we compare it with the TWE and show that physically the TGWE models a fundamentally different balance from the TWE and delivers numerical results considerably different from models based on the TWE. We conclude that the TWE balance cannot be relied upon to produce realistic convection models. Only after the TGWE balance is obtained can the relative importance of terms be assessed.The calculations we report here are based on two types of zonal circulations that are produced by realistically possible convections inside planets, instead of being constructed or assumed.展开更多
This paper investigates the possibility of using the free expansion of gaseous CO2 in portable air-cooling systems. The cooling capacity of the gaseous CO2 free jet expansion was calculated using three different appro...This paper investigates the possibility of using the free expansion of gaseous CO2 in portable air-cooling systems. The cooling capacity of the gaseous CO2 free jet expansion was calculated using three different approaches and the results showed that the simplified calculations would give approximated cooling values with an 11.6% maximum error. The mass flow rate, upstream pressure and cooling capacity of the gaseous CO2 decreased with time. A maximum 48.5 watts of cooling was recorded at minute 4 and a minimum value of 10.4 watts at the end of the test. The drop in cooling capacity is due to the evaporation of the liquid CO2 inside the small cylinder which cools the two-phase CO2 mixture and causes a pressure drop (from 6 MPa to 2.97 MPa), which also affects the mass flow rate of gaseous CO2 exiting the orifice (from 0.56 g/s to 0.24 g/s). If this cooling technique is to be considered in portable compact-cooling systems, the mass, pressure and cooling capacity drop with time must be solved. One of the solutions could be to cover the cylinder with a heating coat to compensate for the heat absorbed by the evaporation of the liquid CO2.展开更多
The present work investigated the effect of the common gaseous pollutants on silver artifacts corrosion. The study will be carried out on manufactured coupons of silver alloy (91 silver, 9 copper) which have chemical ...The present work investigated the effect of the common gaseous pollutants on silver artifacts corrosion. The study will be carried out on manufactured coupons of silver alloy (91 silver, 9 copper) which have chemical composition similar to ancient Egyptian silver artifacts. These coupons will be exposed to gaseous pollutants of each individual gas;such as Sulfur dioxide, Nitrogen dioxide, Carbon dioxide, Hydrogen sulfide and Chlorine. The exposure period will be four weeks in a climate chamber with gas concentration 10 PPM. After the test Examinations by SEM and PM were used to evaluate the effect of each gas and description the morphology of the corrosion layers. The results revealed that all gases reacted with the surface except carbon dioxide. The formed tarnishing layers varied in coverage and density rate. Corrosion products are analyzed by XRD and the results revealed Ag2S, AgCl, Ag2SO4 and Ag2O as corrosion products.展开更多
The original online version of this article Salem, Y. (2017) The Influence of Gaseous Pollutants on Silver Artifacts Tarnishing. Open Journal of Air Pollution, 6, 135-148. doi: 10.4236/ojap.2017.64011 unfortunately co...The original online version of this article Salem, Y. (2017) The Influence of Gaseous Pollutants on Silver Artifacts Tarnishing. Open Journal of Air Pollution, 6, 135-148. doi: 10.4236/ojap.2017.64011 unfortunately contains grammar mistakes. The author wishes to correct the errors. The present work investigated the effect of common gaseous pollutants on silver artifacts. The study was carried out on coupons made of a silver alloy (91 silver and 9% copper) with chemical composition similar to ancient Egyptian silver artifacts. These coupons were exposed to gaseous pollutants such as sulfur dioxide, nitrogen dioxide, carbon dioxide, hydrogen sulfide and chlorine, each gas separately. The exposure period was four weeks inside a climate chamber with 10 PPM concentration of each gas. After each test, examinations by SEM and PM were used to evaluate the effect of each gas and observe the formed tarnish layers. The results revealed that all gases reacted with the surface except carbon dioxide. The formed tarnish layers varied in coverage and density rate, and the heaviest layer was of H<sub>2</sub>S coupons. The tested coupons were analyzed by XRD and the results revealed Ag<sub>2</sub>S, AgCl, Ag<sub>2</sub>SO<sub>4</sub>, Ag(NO<sub>3</sub>)<sub>3</sub>(NO)<sub>3</sub>, AgO and Ag<sub>2</sub>O as corrosion products.展开更多
Because of its high mobility and difficult capture,gaseous arsenic pollution control has become the focus of arsenic pollution control.It mainly exists in the form of highly toxic As_(2)O_(3)in the flue gas.Therefore,...Because of its high mobility and difficult capture,gaseous arsenic pollution control has become the focus of arsenic pollution control.It mainly exists in the form of highly toxic As_(2)O_(3)in the flue gas.Therefore,removing gaseous As_(2)O_(3)from flue gas is of great practical significance for arsenic pollution control.Stabilizing gaseous As_(2)O_(3)on the surface of adsorbents by physical or chemical adsorption is an effective way to reduce the content of arsenic in the flue gas and alleviate arsenic pollution.Over the past few decades,various adsorbents have been developed to capture gaseous As_(2)O_(3)in the flue gas,and their adsorption mechanisms have been studied in detail.Thus,it is necessary to review the strategies of arsenic removal from flue gas by adsorption,which can inspire further research.Based on summarizing the morphological distribution of gaseous As_(2)O_(3)in the flue gas,this review further summarizes the removal of gaseous As_(2)O_(3)by several adsorbents and the effect of temperature and the main components of the flue gas on arsenic adsorption.In addition,the mechanism of arsenic removal based on adsorption in the flue gas is discussed in depth through theoretical calculations,which is the particular focus of this review.Finally,prospects based on the present research state of arsenic removal by adsorption are proposed to provide ideas for developing effective and stable adsorbents for arsenic removal from flue gas.展开更多
Persulfate is considered a convenient and efficient remediation agent for organic contaminated soil.However,the potential risk of sulfur into the soil remediation by persulfate remains ignored.In this study,glass bott...Persulfate is considered a convenient and efficient remediation agent for organic contaminated soil.However,the potential risk of sulfur into the soil remediation by persulfate remains ignored.In this study,glass bottles with different persulfate dosages and groundwater tables were set up to simulate persulfate remediation of organic pollutants(aniline).The results found sulfate to be the main end-product(83.0%–99.5%)of persulfate remediation after10 days.Moreover,H_(2)S accounted for 93.4%–99.4%of sulfur reduction end-products,suggesting that H_(2)S was the final fate of sulfur.H_(2)S was released rapidly after one to three days at a maximum concentration of 33.0 ppm,which is sufficient to make a person uncomfortable.According to the fitted curve results,H_(2)S concentration decreased to a safe concentration(0.15 ppm)after 20–85 days.Meanwhile,the maximum concentration of methanethiol reached 0.6 ppm.These results indicated that secondary pollution from persulfate remediation could release harmful gases over a long time.Therefore,persulfate should be used more carefully as a remediation agent for soil contamination.展开更多
A flow of silicon fluid in the gap between eccentric cylinders was studied experimentally.The condition of gaseous cavitation inception during the rotation of internal cylinder was considered.It was shown that at redu...A flow of silicon fluid in the gap between eccentric cylinders was studied experimentally.The condition of gaseous cavitation inception during the rotation of internal cylinder was considered.It was shown that at reduction of the gap between cylinders Saffman–Taylor instability appeared on surface of the internal cylinder and then gaseous cavitation was observed.Possibility of one uniform gas formation appearance under this type of instability was demonstrated.展开更多
基金the National Natural Science Foundation of China(Nos.41506128,40806045 and 41749903)the Oceanographic Research Vessel Sharing Plan(No.NORC2018-06-25)。
文摘Complex hydrocultural conditions in the estuary affect the migration and transformation of mercury.Using two voyages in July and October 2018,Dissolved Gaseous Mercury(DGM)and Reactive Mercury(RHg)were determined to explore the source,transformation and influence of DGM content in the adjacent waters of Yangtze River Estuary in summer and autumn.The results showed the contents of DGM and RHg in summer were higher than those in autumn,and both of them were higher than those in open sea.In summer and autumn,the Yangtze River brought a higher concentration of DGM,and different flow direction and runoff resulted in differences in the high value region of the surface.The emergence of low-oxygen zones in summer was conducive to the production of DGM.In autumn,windy weather allowed seawater disturbances to promote the release of mercury from the underlying sediments,especially in shallow sea in northwest.RHg showed a higher concentration in the offshore than in the open sea in summer,but there was no such trend in autumn,reflecting the influence of less runoff input.DGM is the main product of RHg reduction,and there was a significant positive correlation between DGM and RHg in summer(r=0.356,P<0.05),while the correlation between DGM and RHg was not significant in autumn due to the influence of light intensity,wind speed and nutrients.The exchange flux of mercury in the adjacent waters of the Yangtze River Estuary was higher than that in the open sea.There was no significant difference of the release flux of mercury in summer and autumn.This article highlighted that the input of mercury from the Yangtze River runoff promotes the release of mercury in seawater,and the hypoxic zone caused by eutrophication is conducive to the production of DGM.
基金supported by the National Natural Science Foundation of China(Grant No.42271312,41201058)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA20070102)+1 种基金the National Key R&D Program of China(Grant No.2018YFB1307504)the Science and Technology Program of Tibet Autonomous Region of China(Grant No.XZ202101ZD0014G).
文摘Theδ18O of ice core enclosed gaseous oxygen(δ18Obub)has been widely used for climate reconstruction in polar regions.Yet,less is known about its climatic implication in the mountainous glaciers as the lack of continuous record.Here,we present a long-term,continuousδ18Obub record from the Tanggula glacier in the central Tibetan Plateau(TP).Based on comparisons of its variation with regional climate and glacier changes,we found that there was a good correlation between the variation of theδ18Obub in this alpine ice core and the accumulation and melting of this glacier.The more developed the firn layer on glacier surface,the more positive theδ18Obub.Conversely,the more intense the glacier melting,the more negative theδ18Obub.Combined with the chronology of ice core enclosed gases,the glacier variations since the late Holocene in the central TP were reconstructed.The result showed that there were four accumulation and three deficit periods of glaciers in this region.The strongest glacier accumulation period was 1610-300 B.C.,which corresponds to the Neoglaciation.The most significant melting period was the last 100 years,which corresponds to the recent global warming.The Medieval Warm Period was relatively significant in the central TP.However,during the Little Ice Age,there was no significant glacier accumulation in the central TP,and even short deficit events occurred.Comparisons of the late Holocene glacier variation in the central TP with glacier and climate variations in the TP and the Northern Hemisphere showed that it was closely related to the North Atlantic Oscillation.
文摘A method combining theoretical analysis with experiment is adopted and the flowing process of Ti-48A1-2Cr-2Nb alloy melt poured in a permanent mould during the centrifugal casting process has been analyzed. A mathematical model of the filling process is established and the forming mechanism of internal gaseous defect is summarized. The results of calculation show that the melt fills the mould with varying cross-section area and inclined angle. The filling speed of the cross-section is a function of filling time. The cross-section area is directly proportional to the filling speed and the inclined angle is inversely proportional to the filling speed at a given rotating speed of the platform. Both of them changes more obvious near the mould entrance. The gaseous defect can be formed in several ways and the centrifugal field has an important influence on the formation of the defect. In addition, the filling process in centrifugal field has been verified by wax experiments and the theoretical analysis are consistent with experimental results.
文摘The paper presented the results regarding the decomposition of gaseous CF<sub>2</sub>ClB<sub>r</sub> bycold plasma method.After two minutes discharge,the maximum decomposition rate of 2660 PaCF<sub>2</sub>ClB<sub>r</sub> pure and 2660 Pa CF<sub>2</sub>ClBr plus 7980 Pa O<sub>2</sub> reached 60% and 80%,respectively.The pa-per also studied the cold plasma gas phase chemistry reaction mechanism of CF<sub>2</sub>ClBr at low pres-sure,and the pressure effects of CF<sub>2</sub>ClBr and added gas（He,N<sub>2</sub>,O<sub>2</sub> and dry air）on the CF<sub>2</sub>ClBrdecomposition respectively by cold plasma method.These studies will be helpful to application ofcold plasma method in the treatment of hazardous gaseous wastes.
文摘BACKGROUND: Hepatic ischemia-reperfusion injury is one of the major problems in liver transplantation. This study aimed to investigate the possible improvement of aerobic metabolism of ischemic donor livers through systemic persufflation with gaseous oxygen in rinse solution. METHODS: Thirty rats were randomly divided into 3 groups. In group A (control, n = 10), the livers were perfused with 4 ℃ lactic acid ringer’s solution through the can-nulated portal vein for 25 minutes soon after warm ischemia for 30 minutes. In group B (n =10), the livers were treated the same way as in group A except for addition of gaseous oxygen in the rinse solution. In group C (n =10), the livers were treated similarly as in group B except for addition of superoxide dismutase (SOD) in the rinse solution. RESULTS: In group B, the malondialdehyde(MDA)levels in hepatic tissues after perfusion were significantly increased (P【 0. 01), whereas the SOD levels were markedly decreased (P 【0.01). After combined use with antioxidant in group C, the levels of MDA and SOD in hepatic tissues after perfusion recovered significantly (P【0.01). CONCLUSION: Perfusion by gaseous oxygen persufQation in combination with antioxidative agents is promising for resuscitating the ischemically altered livers for successful transplantation.
基金financially supported by the National Natural Science Foundation of China(No.U1862103)
文摘This work proposed to use the ionic liquid [EMIM][BF_4] as absorbent for the absorption of gaseous acetic acid. The feasibility of this technology was investigated from molecular level to industrial scale. The acetic acid absorption experiment was carried out using [EMIM][BF_4],and the removal ratio of acetic acid in the gas product can achieve 88.6% at 20C under atmospheric pressure at the laboratory scale. Based on the experimental results, a reliable strict equilibrium phase model embedding the parameters of the UNIFAC model was established. On this basis, the conceptual process design and optimization of acetic acid removal by [EMIM][BF_4] at an industrial scale was done, and the most suitable design and operation parameters were obtained. For a further step, the binding energy between [EMIM][BF_4] and acetic acid was calculated to give some insights into the separation mechanism, and the results indicate that the interaction between acetic acid and IL is much stronger than that between nitrogen and IL. Moreover, hydrogen bond can be formed between the cation-acetic acid as well as the anion-acetic acid.
文摘ABSTRACT The Raman intensitics of gas molecules were found to be enormously enhanced inthe presence of Hg-microdroplets.The enhancement factor for the molecules studied was foundto be over 20.
基金Project supported by the National Natural Science Foundation of China(Grant No.51305204)
文摘Both experimental and numerical studies were presented on the flow field characteristics in the process of gaseous jet impinging on liquid–water column. The effects of the impinging process on the working performance of rocket engine were also analyzed. The experimental results showed that the liquid–water had better flame and smoke dissipation effect in the process of gaseous jet impinging on liquid–water column. However, the interaction between the gaseous jet and the liquid–water column resulted in two pressure oscillations with large amplitude appearing in the combustion chamber of the rocket engine with instantaneous pressure increased by 17.73% and 17.93%, respectively. To analyze the phenomena, a new computational method was proposed by coupling the governing equations of the MIXTURE model with the phase change equations of water and the combustion equation of propellant. Numerical simulations were carried out on the generation of gas, the accelerate gas flow, and the mutual interaction between gaseous jet and liquid–water column.Numerical simulations showed that a cavity would be formed in the liquid–water column when gaseous jet impinged on the liquid–water column. The development speed of the cavity increased obviously after each pressure oscillation. In the initial stage of impingement, the gaseous jet was blocked due to the inertia effect of high-density water, and a large amount of gas gathered in the area between the nozzle throat and the gas–liquid interface. The shock wave was formed in the nozzle expansion section. Under the dual action of the reverse pressure wave and the continuously ejected high-temperature gas upstream, the shock wave moved repeatedly in the nozzle expansion section, which led to the flow of gas in the combustion chamber being blocked, released, re-blocked, and re-released. This was also the main reason for the pressure oscillations in the combustion chamber.
文摘BaTiO3∶Mn0.006Smx(x=0.001, 0.002, 0.003, 0.004, 0.006 respectively) ceramics were prepared by using sol-gel method and their resistivities at different temperatures were measured. The results showed that Mn element may enhance the PTC characteristics of BaTiO3 ceramics. But the doped Mn element deteriorated the room temperature resistivities of the modified BaTiO3 ceramics which were greater than 105 Ω·m. Then, rare earth element Sm was penetrated into BaTiO3∶Mn0.06Smx ceramics in gaseous state, which largely decreased the room temperature resistivity to 3.20 Ω·m, and appeared as a NTC effect instead of PTC effect. The forming mechanism of NTC effect was explored through analyses of SEM and electric properties of Sm-penetrated BaTiO3∶Mn0.006Smx ceramics.
文摘The fluorescence of gaseous CS_2 was studied by laser - induced fluorescence (LIF) method. Aworking curve of gaseous CS_2 was obtained and the detection limit was less than 1 ppm. The time - resolvedfluorescence emission spectrum of CS_2 vapor was recorde
基金Under the auspices of the National Natural Science Foundation of China(No.41506128)Shandong Natural Science Foundation(No.ZR2018MD004)。
文摘From 28 March to 17 April, 2018, different forms of mercury(Hg) in the Yellow Sea and Bohai Sea were measured to study the influencing factors on the distribution and transformation of Hg in spring using a shared cruise. The mean concentration of dissolved gaseous mercury(DGM) in the surface water of the Yellow and Bohai Seas was(44.3 ± 43.9) pg/L, which was close to that in mid-latitude oceans and deep seas. The ratio of DGM to THg(total mercury) was lower than in the oceans and in the Yellow and Bohai Seas in summer or fall. DGM concentrations in surface water were highest in the central part of the South Yellow Sea and were higher than those in the Bohai Sea, and their spatial distributions were consistent with RHg(reactive mercury). DGM and RHg correlated positively with water temperature in surface seawater(r = 0.506, P < 0.01;r = 0.278, P < 0.05). The concentrations of both DGM and RHg in surface water were controlled by solar radiation and water temperature. Foggy weather did not benefit the production of DGM and RHg. DGM in the bottom seawater was mainly affected by Dissolved Oxygen and water temperature(r =-0.366, P < 0.01;r = 0.331, P < 0.01), produced mainly by anaerobic reactions of the bottom seawater and sediment microorganisms. The bottom DGM concentrations in the Yellow and Bohai Seas were the highest, and DGM produced in bottom seawater and sediment plays a more important role than the surface water in spring. The concentrations of DGM and RHg in the surface and bottom water in the South Yellow Sea were all higher than those in the middle layer. Vertical variations in the North Yellow Sea and the Bohai Sea were small. The production and distribution of DGM and RHg were influenced by differences of latitude and by the Yellow Sea warm current in spring.
基金supported by the Chinese Youth 1000 Talents Program and the Open Project of the State Key Laboratory of Planetary Sciences, Macao University of Science and Technologysupported by the Science and Technology Facilities Council grant ST/R000891/1by the Macao Science and Technology Development Fund grants (007/2016/A1 and 001/2016/AFJ)
文摘To infer the internal equilibrium structure of a gaseous planet, especially the equation of state(EOS) and size of its inner core,requires accurate determination of lower-order zonal gravitational coefficients. Modeling of the gravitational signature associated with deep zonal circulation depends critically upon reliable subtraction of the dynamical components from totally derived gravitational coefficients. In the era of the Juno mission and the Grand Finale phase of the Cassini mission, it is timely and necessary to revisit and examine the so-called ‘Thermal Wind Equation(TWE)’, which has been extensively utilized to diagnose the dynamical parts of the gravitational fields measured by the two spacecrafts. TWE treats as negligible a few terms in the full equation of balance. However, the self-gravitational anomaly of the distorted fluid, unlike oblateness effects of solid-body rotation, is not a priori minor and thus should not be neglected in the name of approximation. Another equation, the ‘Thermal Gravitational Wind Equation(TGWE)’, includes this important additional term;we compare it with the TWE and show that physically the TGWE models a fundamentally different balance from the TWE and delivers numerical results considerably different from models based on the TWE. We conclude that the TWE balance cannot be relied upon to produce realistic convection models. Only after the TGWE balance is obtained can the relative importance of terms be assessed.The calculations we report here are based on two types of zonal circulations that are produced by realistically possible convections inside planets, instead of being constructed or assumed.
文摘This paper investigates the possibility of using the free expansion of gaseous CO2 in portable air-cooling systems. The cooling capacity of the gaseous CO2 free jet expansion was calculated using three different approaches and the results showed that the simplified calculations would give approximated cooling values with an 11.6% maximum error. The mass flow rate, upstream pressure and cooling capacity of the gaseous CO2 decreased with time. A maximum 48.5 watts of cooling was recorded at minute 4 and a minimum value of 10.4 watts at the end of the test. The drop in cooling capacity is due to the evaporation of the liquid CO2 inside the small cylinder which cools the two-phase CO2 mixture and causes a pressure drop (from 6 MPa to 2.97 MPa), which also affects the mass flow rate of gaseous CO2 exiting the orifice (from 0.56 g/s to 0.24 g/s). If this cooling technique is to be considered in portable compact-cooling systems, the mass, pressure and cooling capacity drop with time must be solved. One of the solutions could be to cover the cylinder with a heating coat to compensate for the heat absorbed by the evaporation of the liquid CO2.
文摘The present work investigated the effect of the common gaseous pollutants on silver artifacts corrosion. The study will be carried out on manufactured coupons of silver alloy (91 silver, 9 copper) which have chemical composition similar to ancient Egyptian silver artifacts. These coupons will be exposed to gaseous pollutants of each individual gas;such as Sulfur dioxide, Nitrogen dioxide, Carbon dioxide, Hydrogen sulfide and Chlorine. The exposure period will be four weeks in a climate chamber with gas concentration 10 PPM. After the test Examinations by SEM and PM were used to evaluate the effect of each gas and description the morphology of the corrosion layers. The results revealed that all gases reacted with the surface except carbon dioxide. The formed tarnishing layers varied in coverage and density rate. Corrosion products are analyzed by XRD and the results revealed Ag2S, AgCl, Ag2SO4 and Ag2O as corrosion products.
文摘The original online version of this article Salem, Y. (2017) The Influence of Gaseous Pollutants on Silver Artifacts Tarnishing. Open Journal of Air Pollution, 6, 135-148. doi: 10.4236/ojap.2017.64011 unfortunately contains grammar mistakes. The author wishes to correct the errors. The present work investigated the effect of common gaseous pollutants on silver artifacts. The study was carried out on coupons made of a silver alloy (91 silver and 9% copper) with chemical composition similar to ancient Egyptian silver artifacts. These coupons were exposed to gaseous pollutants such as sulfur dioxide, nitrogen dioxide, carbon dioxide, hydrogen sulfide and chlorine, each gas separately. The exposure period was four weeks inside a climate chamber with 10 PPM concentration of each gas. After each test, examinations by SEM and PM were used to evaluate the effect of each gas and observe the formed tarnish layers. The results revealed that all gases reacted with the surface except carbon dioxide. The formed tarnish layers varied in coverage and density rate, and the heaviest layer was of H<sub>2</sub>S coupons. The tested coupons were analyzed by XRD and the results revealed Ag<sub>2</sub>S, AgCl, Ag<sub>2</sub>SO<sub>4</sub>, Ag(NO<sub>3</sub>)<sub>3</sub>(NO)<sub>3</sub>, AgO and Ag<sub>2</sub>O as corrosion products.
基金supported by the National Science Fund for Excellent Young Scholars of China (No.52022111)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No.52121004)+1 种基金the Hunan High Tech Industry Science and Technology Innovation Leading Plan Project (No.2020SK2006)the Huxiang Youth Talent Support Program (No.2020RC3012)。
文摘Because of its high mobility and difficult capture,gaseous arsenic pollution control has become the focus of arsenic pollution control.It mainly exists in the form of highly toxic As_(2)O_(3)in the flue gas.Therefore,removing gaseous As_(2)O_(3)from flue gas is of great practical significance for arsenic pollution control.Stabilizing gaseous As_(2)O_(3)on the surface of adsorbents by physical or chemical adsorption is an effective way to reduce the content of arsenic in the flue gas and alleviate arsenic pollution.Over the past few decades,various adsorbents have been developed to capture gaseous As_(2)O_(3)in the flue gas,and their adsorption mechanisms have been studied in detail.Thus,it is necessary to review the strategies of arsenic removal from flue gas by adsorption,which can inspire further research.Based on summarizing the morphological distribution of gaseous As_(2)O_(3)in the flue gas,this review further summarizes the removal of gaseous As_(2)O_(3)by several adsorbents and the effect of temperature and the main components of the flue gas on arsenic adsorption.In addition,the mechanism of arsenic removal based on adsorption in the flue gas is discussed in depth through theoretical calculations,which is the particular focus of this review.Finally,prospects based on the present research state of arsenic removal by adsorption are proposed to provide ideas for developing effective and stable adsorbents for arsenic removal from flue gas.
基金supported by the National Key R&D Program of China (No.2018YFC1800506)the Key R&D Program of Zhejiang Province (No.2020C03083)。
文摘Persulfate is considered a convenient and efficient remediation agent for organic contaminated soil.However,the potential risk of sulfur into the soil remediation by persulfate remains ignored.In this study,glass bottles with different persulfate dosages and groundwater tables were set up to simulate persulfate remediation of organic pollutants(aniline).The results found sulfate to be the main end-product(83.0%–99.5%)of persulfate remediation after10 days.Moreover,H_(2)S accounted for 93.4%–99.4%of sulfur reduction end-products,suggesting that H_(2)S was the final fate of sulfur.H_(2)S was released rapidly after one to three days at a maximum concentration of 33.0 ppm,which is sufficient to make a person uncomfortable.According to the fitted curve results,H_(2)S concentration decreased to a safe concentration(0.15 ppm)after 20–85 days.Meanwhile,the maximum concentration of methanethiol reached 0.6 ppm.These results indicated that secondary pollution from persulfate remediation could release harmful gases over a long time.Therefore,persulfate should be used more carefully as a remediation agent for soil contamination.
文摘A flow of silicon fluid in the gap between eccentric cylinders was studied experimentally.The condition of gaseous cavitation inception during the rotation of internal cylinder was considered.It was shown that at reduction of the gap between cylinders Saffman–Taylor instability appeared on surface of the internal cylinder and then gaseous cavitation was observed.Possibility of one uniform gas formation appearance under this type of instability was demonstrated.
