Electrocatalytic CO_(2)reduction(ECR)to produce value-added fuels and chemicals using renewable electricity is an emerging strategy to mitigate global warming and decrease reliance on fossil fuels.Among various ECR pr...Electrocatalytic CO_(2)reduction(ECR)to produce value-added fuels and chemicals using renewable electricity is an emerging strategy to mitigate global warming and decrease reliance on fossil fuels.Among various ECR products,liquid oxygenates(Oxys)are especially attractive due to their high energy density,high safety and transportability that could be adapted to the existing infrastructure and transportation system.However,efficiently generating these highly reduced oxygen-containing products by ECR remains challenging due to the complexity of coupled proton and electron transfer processes.In recent years,in-depth studies of reaction mechanisms have advanced the design of catalysts and the regulation of reaction systems for ECR to produce Oxys,Here,by focusing on the production of typical Oxys,such as methanol,acetic acid,ethanol,acetone,n-propanol,and isopropanol,we outline various reaction paths and key intermediates for the electrochemical conversion of CO_(2)into these target products.We also summarize the current research status and recent advances in catalysts based on their elemental composition,and consider recent studies on the change of catalyst geometry and electronic structure,as well as the optimization of reaction systems to increase ECR performance.Finally,we analyze the challenges in the field of ECR to Oxys and provide an outlook on future directions for high-efficiency catalyst prediction and design,as well as the development of advanced reaction systems.展开更多
For capturing and recycling of CO_(2)in the internal combustion engine,Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techn...For capturing and recycling of CO_(2)in the internal combustion engine,Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle.However,due to the water spray nozzle need to be installed on the cylinder,which increases the cylinder head design difficulty and makes the combustion conditions become more complicated.In this paper,a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines.The proposed new method uses liquid oxygen to solidify part of cooled CO_(2)from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system.The other part of CO_(2)is sent to inlet system and mixed with oxygen,which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable.Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program.The effects of exhaust gas recirculation(EGR)rate are analyzed on the temperatures,the pressures and the instantaneous heat release rates when the EGR rate is more than 8%.The possibility of enclosing intake and exhaust system for engine is verified.The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO_(2)capture experiment is carried out.The experimental results show that when the EGR rate is 36%for the optimum EGR rate.When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min,respectively,21.50-701.30 g dry ice is obtained.This research proposes a new design method which can capture CO_(2)for vehicular internal combustion engine.展开更多
The thermal protection of rocket engines is a crucial aspect of rocket engine design.In this paper,the gas film/regenerative composite cooling of the liquid oxygen/liquid methane(LOX/LCH4)rocket engine thrust chamber ...The thermal protection of rocket engines is a crucial aspect of rocket engine design.In this paper,the gas film/regenerative composite cooling of the liquid oxygen/liquid methane(LOX/LCH4)rocket engine thrust chamber was investigated.A gas film/regenerative composite cooling model was developed based on the Grisson gas film cooling efficiency formula and the one-dimensional regenerative cooling model.The accuracy of the model was validated through experiments conducted on a 6 kg/s level gas film/regenerative composite cooling thrust chamber.Additionally,key parameters related to heat transfer performance were calculated.The results demonstrate that the model is sufficiently accurate to be used as a preliminary design tool.The temperature rise error of the coolant,when compared with the experimental results,was found to be less than 10%.Although the pressure drop error is relatively large,the calculated results still provide valuable guidance for heat transfer analysis.In addition,the performance of composite cooling is observed to be superior to regenerative cooling.Increasing the gas film flow rate results in higher cooling efficiency and a lower gas-side wall temperature.Furthermore,the position at which the gas film is introduced greatly impacts the cooling performance.The optimal introduction position for the gas film is determined when the film is introduced from a single row of holes.This optimal introduction position results in a more uniform wall temperature distribution and reduces the peak temperature.Lastly,it is observed that a double row of holes,when compared to a single row of holes,enhances the cooling effect in the superposition area of the gas film and further lowers the gas-side wall temperature.These results provide a basis for the design of gas film/regenerative composite cooling systems.展开更多
Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid ...Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid oxygen tanks is analyzed under various Bond numbers(Bo)and magnetic Bond numbers(Bom).The results show that the magnetic field has the effect of repositioning the liquid oxygen in the tank when the gravity field is not enough or absent.Additionally,the gas-liquid interface has a periodic fluctuation during the process due to the inhomogeneous Kelvin force distribution,and more effective suppression of fluctuation can be achieved under the condition of a larger Bom.The new method of controlling gas-liquid interface of liquid oxygen tank under micro gravity condition is hoped to be developed in the future.展开更多
The fluid-structure interaction may occur in space launch vehicles,which would lead to bad performance of vehicles,damage equipments on vehicles,or even affect astronauts＇ health.In this paper,analysis on dynamic beh...The fluid-structure interaction may occur in space launch vehicles,which would lead to bad performance of vehicles,damage equipments on vehicles,or even affect astronauts＇ health.In this paper,analysis on dynamic behavior of liquid oxygen （LOX） feeding pipe system in a large scale launch vehicle is performed,with the effect of fluid-structure interaction （FSI） taken into consideration.The pipe system is simplified as a planar FSI model with Poisson coupling and junction coupling.Numerical tests on pipes between the tank and the pump are solved by the finite volume method.Results show that restrictions weaken the interaction between axial and lateral vibrations.The reasonable results regarding frequencies and modes indicate that the FSI affects substantially the dynamic analysis,and thus highlight the usefulness of the proposed model.This study would provide a reference to the pipe test,as well as facilitate further studies on oscillation suppression.展开更多
Hierarchical BiOBr microspheres with oxygen vacancies, which can be used for the dyes removal, have been synthesized successfully in the presence of different kinds of ionic liquids. It was revealed that BiOBr prepare...Hierarchical BiOBr microspheres with oxygen vacancies, which can be used for the dyes removal, have been synthesized successfully in the presence of different kinds of ionic liquids. It was revealed that BiOBr prepared by the ionic liquids with short chain length exhibited higher photocatalytic activity in the degradation of methyl orange （MO） under visible light. The experimental results showed that the phenomenon of the photocatalytic degradation of MO can be explained by the photoluminescence spectra.展开更多
A few factors affecting plasma oxidation desulfurization of ethyl- thioether were investigated.Under the typical conditions,the conversion and degree of desulfurization of ethyl-thioether can be achieved up to 88% and...A few factors affecting plasma oxidation desulfurization of ethyl- thioether were investigated.Under the typical conditions,the conversion and degree of desulfurization of ethyl-thioether can be achieved up to 88% and 79% respectively.展开更多
The stereochemistry of two 6, 9-oxygen bridge dibenzocyclooctadiene lignans from Kadsura coccinea, are difficult to separate and very unstable. The present study was designed to develop a high-performance liquid chrom...The stereochemistry of two 6, 9-oxygen bridge dibenzocyclooctadiene lignans from Kadsura coccinea, are difficult to separate and very unstable. The present study was designed to develop a high-performance liquid chromatography using circular dichroism detection for the analysis of the stereochemistry. A new 6, 9-oxygen bridge dibenzocyclooctadiene lignans named Kadsulignan Q was firstly found with an S-biphenyl configuration. The other compound was identified as Kadsulignan L with an R- biphenyl configuration. In order to obtain kinetic data on their reversible interconversion, the stability was measured at different deuterated solvents such as deuterated methanol, deuterated chloroform and deuterated dimethylsulfoxide. The lignans were more unstable and converted more easily in deuterated methanol than in deuterated chloroform and deuterated dimethylsulfoxide.展开更多
This paper reviews the status of the gas-to-liquids (GTL) industry-including current commercial plants, announced projects and the technologies that are likely to be implemented in these future projects. Today, only 3...This paper reviews the status of the gas-to-liquids (GTL) industry-including current commercial plants, announced projects and the technologies that are likely to be implemented in these future projects. Today, only 35,000 B/D of GTL products (0.1% of market) are manufactured from commercial gas-based plants. Advances in technology have lowered the cost of plants to the point where GTL plants can be profitable at crude oil prices of ＄16/B. The advanced stage of development of several proposed GTL projects and attractive integrated economics, for both the gas field and plant, show that GTL can be a significant alternative for monetizing natural gas in the 21st century. GTL technologies includes more than Fischer-Tropsch technology and extends to other liquid fuels, especially in the oxygenate family (methanol, dimethyl ether, etc.).展开更多
<span style="font-family:Verdana;">The successful application of assisted reproductive techniques (ARTs) in ovine as in other mammal species relies on many factors among which the quality of the semen ...<span style="font-family:Verdana;">The successful application of assisted reproductive techniques (ARTs) in ovine as in other mammal species relies on many factors among which the quality of the semen used. After collection, semen samples are generally processed for storage (liquid storage or cryoconservation) before being used for insemination or </span><i><i><span style="font-family:Verdana;">in vitro</span></i><span></span></i><span style="font-family:Verdana;"> embryo production. During the liquid storage process, sperm cells are exposed to artificial conditions which lead to oxidative stress—the imbalance between pro-oxidants and antioxidants (AO), following overproduction of reactive oxygen species (ROS)</span><span style="font-family:Verdana;">—resulting in ultrastructural, biochemical and functional damages of spermatozoa. Especially, viability, motility, mitochondrial activity, membrane integrity, and</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">acrosome integrity are reduced while morphological abnormalities, DNA fragmentation, and lipid peroxidation (LPO) are increased, affecting the fertilizing ability and subsequent early embryonic development when using standard extenders. Indeed, an optimal semen extender must not only regulate and support an environment of adequate pH and buffering capacity to protect spermatozoa from osmotic and cooling stresses, but, also prevent the generation and/or scavenge excess ROS. To improve ram semen liquid storage, several methods have been developed with the supplementation of extenders with antioxidants or antioxidant like-compounds (enzymes, amino-acids, vitamins, plant extracts), seminal plasma, sugars, fatty acids, and nanoparticles being a relevant approach. Promising results have been registered with the supplementation of extenders with these compounds, confirming they can be used to preserve ram semen quality and fertility. Therefore, the present review provides an updated overview of the damages and associated mechanisms that ram spermatozoa undergo during liquid storage. Moreover, the supplementation of extenders with different compounds as a tool to improve semen storage is also discussed as well as their efficiency to reduce and/or prevent sperm damages during storage.</span>展开更多
The solid oxide electrolyte galvanic cell represented by Mo/Cr,Cr_2O_3//ZrO_2(MgO)//[O], Ce_2O_2S/Mo+ZrO_2 ceramic-metal,Mo have been used to study the thermodynamic proper- ties of Fe-Nb-Ce solution containing trace ...The solid oxide electrolyte galvanic cell represented by Mo/Cr,Cr_2O_3//ZrO_2(MgO)//[O], Ce_2O_2S/Mo+ZrO_2 ceramic-metal,Mo have been used to study the thermodynamic proper- ties of Fe-Nb-Ce solution containing trace carbon at 1600℃.The equilibrium constant for the reaction Ce_2O_2S=2[Ce]+2[O]+[S] and the standard free energy of formation of Ce_2O_2S have been determined in liquid iron at 1600℃ as K=4.395×10^(-15).ΔG_(Ce_2)O_2S=-514.786 kJ·mol^(-1).The interaction coefficients between cerium and niobium are found to he e_(Nd)^(Ce)=-2.306,e_(Nd)^(Ce)=-3.481. The equilibrium products began to contain the compound NbC with the increase of Nh concentration in the condition of trace carbon.The formation of NbC is discussed in this work.The standard free energy of formation of NbC in liquid iron at 1600℃ have been de- termined as ΔG_(NbC)=-87.111 kJ·mol^(-1).展开更多
Dry-spun Carbon Nanotube(CNT)fibers were surface-modified by atmospheric pressure oxygen plasma functionalization using a well controlled and continuous process.The fibers were characterized by scanning electron micro...Dry-spun Carbon Nanotube(CNT)fibers were surface-modified by atmospheric pressure oxygen plasma functionalization using a well controlled and continuous process.The fibers were characterized by scanning electron microscopy(SEM),Raman spectroscopy,and X-ray Photoelectron Spectroscopy(XPS).It was found from the conducted electrochemical measurements that the functionalized fibers showed a 132.8% increase in specific capacitance compared to non-functionalized fibers.Dye-adsorption test and the obtained Randles-Sevcik plot demonstrated that the oxygen plasma functionalized fibers exhibited increased surface area.It was further established by Brunauer-Emmett-Teller(BET)measurements that the surface area of the CNT fibers was increased from 168.22 m^2/g to 208.01 m^2/g after plasma functionalization.The pore size distribution of the fibers was also altered by this processing.The improved electrochemical data was attributed to enhanced wettability,increased surface area,and the presence of oxygen functional groups,which promoted the capacitance of the fibers.Fiber supercapacitors were fabricated from the oxygen plasma functionalized CNT fiber electrodes using different electrolyte systems.The devices with functionalized electrodes exhibited excellent cyclic stability(93.2% after 4000 cycles),flexibility,bendability,and good energy densities.At 0.5 m A/cm^2,the EMIMBF4 device revealed a specific capacitance,which is 27% and 65%greater than the specific capacitances of devices using EMIMTFSI and H2SO4 electrolytes,respectively.The practiced in this work plasma surface processing can be employed in other applications where fibers,yarns,ribbons,and sheets need to be chemically modified.展开更多
A mechanism of oxygen transportation in Czochralski growth of silicon crystals under a horizontal magnetic field (HMCZ) is proposed. Oxygen depleted surface melt, driven to the growth interface by the thermal Marangon...A mechanism of oxygen transportation in Czochralski growth of silicon crystals under a horizontal magnetic field (HMCZ) is proposed. Oxygen depleted surface melt, driven to the growth interface by the thermal Marangoni flow, determines oxygen concentration in the grown crystals. Systematic study was carried out to investigate effects of growth parameters on oxygen incorporation into crystals.展开更多
基金financial supports from the National Natural Science Foundation of China(52201237)the Talent Introduction Project of Chinese Academy of Sciences(E344011)+4 种基金the Shenzhen High Level Talent Team Project(KQTD2022110109364705)the Joint Research Project of China Merchants Group and SIAT(E2Z1521)the Cross Institute Joint Research Youth Team Project of SIAT(E25427)National Natural Science Foundation of China(52402136)the China Postdoctoral Science Foundation(E325281005)。
文摘Electrocatalytic CO_(2)reduction(ECR)to produce value-added fuels and chemicals using renewable electricity is an emerging strategy to mitigate global warming and decrease reliance on fossil fuels.Among various ECR products,liquid oxygenates(Oxys)are especially attractive due to their high energy density,high safety and transportability that could be adapted to the existing infrastructure and transportation system.However,efficiently generating these highly reduced oxygen-containing products by ECR remains challenging due to the complexity of coupled proton and electron transfer processes.In recent years,in-depth studies of reaction mechanisms have advanced the design of catalysts and the regulation of reaction systems for ECR to produce Oxys,Here,by focusing on the production of typical Oxys,such as methanol,acetic acid,ethanol,acetone,n-propanol,and isopropanol,we outline various reaction paths and key intermediates for the electrochemical conversion of CO_(2)into these target products.We also summarize the current research status and recent advances in catalysts based on their elemental composition,and consider recent studies on the change of catalyst geometry and electronic structure,as well as the optimization of reaction systems to increase ECR performance.Finally,we analyze the challenges in the field of ECR to Oxys and provide an outlook on future directions for high-efficiency catalyst prediction and design,as well as the development of advanced reaction systems.
基金Supported by National Natural Science Foundation of China(Grant No.51176082)Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions of China(Grant No.CIT&TCD20140311)Beijing Municipal Natural Science Foundation of China(Grant No.SQKZ201510016004)
文摘For capturing and recycling of CO_(2)in the internal combustion engine,Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle.However,due to the water spray nozzle need to be installed on the cylinder,which increases the cylinder head design difficulty and makes the combustion conditions become more complicated.In this paper,a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines.The proposed new method uses liquid oxygen to solidify part of cooled CO_(2)from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system.The other part of CO_(2)is sent to inlet system and mixed with oxygen,which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable.Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program.The effects of exhaust gas recirculation(EGR)rate are analyzed on the temperatures,the pressures and the instantaneous heat release rates when the EGR rate is more than 8%.The possibility of enclosing intake and exhaust system for engine is verified.The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO_(2)capture experiment is carried out.The experimental results show that when the EGR rate is 36%for the optimum EGR rate.When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min,respectively,21.50-701.30 g dry ice is obtained.This research proposes a new design method which can capture CO_(2)for vehicular internal combustion engine.
基金supported by the National Science Fund Project(No.2019-JCJQ-ZQ-019)the Innovative Research Group Project of National Natural Science Foundation of China(No.T2221002).
文摘The thermal protection of rocket engines is a crucial aspect of rocket engine design.In this paper,the gas film/regenerative composite cooling of the liquid oxygen/liquid methane(LOX/LCH4)rocket engine thrust chamber was investigated.A gas film/regenerative composite cooling model was developed based on the Grisson gas film cooling efficiency formula and the one-dimensional regenerative cooling model.The accuracy of the model was validated through experiments conducted on a 6 kg/s level gas film/regenerative composite cooling thrust chamber.Additionally,key parameters related to heat transfer performance were calculated.The results demonstrate that the model is sufficiently accurate to be used as a preliminary design tool.The temperature rise error of the coolant,when compared with the experimental results,was found to be less than 10%.Although the pressure drop error is relatively large,the calculated results still provide valuable guidance for heat transfer analysis.In addition,the performance of composite cooling is observed to be superior to regenerative cooling.Increasing the gas film flow rate results in higher cooling efficiency and a lower gas-side wall temperature.Furthermore,the position at which the gas film is introduced greatly impacts the cooling performance.The optimal introduction position for the gas film is determined when the film is introduced from a single row of holes.This optimal introduction position results in a more uniform wall temperature distribution and reduces the peak temperature.Lastly,it is observed that a double row of holes,when compared to a single row of holes,enhances the cooling effect in the superposition area of the gas film and further lowers the gas-side wall temperature.These results provide a basis for the design of gas film/regenerative composite cooling systems.
基金supported by the Natural Science Foundation of China(No.51706190)the State Scholarship Fund of China Scholarship Council。
文摘Due to the paramagnetic property of liquid oxygen,the Kelvin force can be induced in liquid oxygen under non-uniform magnetic field.Based on the volume of fluid(VOF)model,the positioning effect of the force in liquid oxygen tanks is analyzed under various Bond numbers(Bo)and magnetic Bond numbers(Bom).The results show that the magnetic field has the effect of repositioning the liquid oxygen in the tank when the gravity field is not enough or absent.Additionally,the gas-liquid interface has a periodic fluctuation during the process due to the inhomogeneous Kelvin force distribution,and more effective suppression of fluctuation can be achieved under the condition of a larger Bom.The new method of controlling gas-liquid interface of liquid oxygen tank under micro gravity condition is hoped to be developed in the future.
文摘The fluid-structure interaction may occur in space launch vehicles,which would lead to bad performance of vehicles,damage equipments on vehicles,or even affect astronauts＇ health.In this paper,analysis on dynamic behavior of liquid oxygen （LOX） feeding pipe system in a large scale launch vehicle is performed,with the effect of fluid-structure interaction （FSI） taken into consideration.The pipe system is simplified as a planar FSI model with Poisson coupling and junction coupling.Numerical tests on pipes between the tank and the pump are solved by the finite volume method.Results show that restrictions weaken the interaction between axial and lateral vibrations.The reasonable results regarding frequencies and modes indicate that the FSI affects substantially the dynamic analysis,and thus highlight the usefulness of the proposed model.This study would provide a reference to the pipe test,as well as facilitate further studies on oscillation suppression.
基金supported by funding from The Chinese Ministry of Education for the Scientific Key Project (No. 109094)
文摘Hierarchical BiOBr microspheres with oxygen vacancies, which can be used for the dyes removal, have been synthesized successfully in the presence of different kinds of ionic liquids. It was revealed that BiOBr prepared by the ionic liquids with short chain length exhibited higher photocatalytic activity in the degradation of methyl orange （MO） under visible light. The experimental results showed that the phenomenon of the photocatalytic degradation of MO can be explained by the photoluminescence spectra.
基金The project was supported by National Natural Science Foundation of China
文摘A few factors affecting plasma oxidation desulfurization of ethyl- thioether were investigated.Under the typical conditions,the conversion and degree of desulfurization of ethyl-thioether can be achieved up to 88% and 79% respectively.
基金supported by the PAPD(Priority Academic Program Development)of Jiangsu Higher Education Institutions,University Science Research Project of Jiangsu Province(No.09KJB350002)National Key Technology R&D Program(No.2012BAI30B02),National Natural Science Foundation of China(No.30901853)Hepatic Fibrosis Innovative Medicine-Research and Development of Fructus Schisandrae capsule(No.F12-157-9-00)
文摘The stereochemistry of two 6, 9-oxygen bridge dibenzocyclooctadiene lignans from Kadsura coccinea, are difficult to separate and very unstable. The present study was designed to develop a high-performance liquid chromatography using circular dichroism detection for the analysis of the stereochemistry. A new 6, 9-oxygen bridge dibenzocyclooctadiene lignans named Kadsulignan Q was firstly found with an S-biphenyl configuration. The other compound was identified as Kadsulignan L with an R- biphenyl configuration. In order to obtain kinetic data on their reversible interconversion, the stability was measured at different deuterated solvents such as deuterated methanol, deuterated chloroform and deuterated dimethylsulfoxide. The lignans were more unstable and converted more easily in deuterated methanol than in deuterated chloroform and deuterated dimethylsulfoxide.
文摘This paper reviews the status of the gas-to-liquids (GTL) industry-including current commercial plants, announced projects and the technologies that are likely to be implemented in these future projects. Today, only 35,000 B/D of GTL products (0.1% of market) are manufactured from commercial gas-based plants. Advances in technology have lowered the cost of plants to the point where GTL plants can be profitable at crude oil prices of ＄16/B. The advanced stage of development of several proposed GTL projects and attractive integrated economics, for both the gas field and plant, show that GTL can be a significant alternative for monetizing natural gas in the 21st century. GTL technologies includes more than Fischer-Tropsch technology and extends to other liquid fuels, especially in the oxygenate family (methanol, dimethyl ether, etc.).
文摘<span style="font-family:Verdana;">The successful application of assisted reproductive techniques (ARTs) in ovine as in other mammal species relies on many factors among which the quality of the semen used. After collection, semen samples are generally processed for storage (liquid storage or cryoconservation) before being used for insemination or </span><i><i><span style="font-family:Verdana;">in vitro</span></i><span></span></i><span style="font-family:Verdana;"> embryo production. During the liquid storage process, sperm cells are exposed to artificial conditions which lead to oxidative stress—the imbalance between pro-oxidants and antioxidants (AO), following overproduction of reactive oxygen species (ROS)</span><span style="font-family:Verdana;">—resulting in ultrastructural, biochemical and functional damages of spermatozoa. Especially, viability, motility, mitochondrial activity, membrane integrity, and</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">acrosome integrity are reduced while morphological abnormalities, DNA fragmentation, and lipid peroxidation (LPO) are increased, affecting the fertilizing ability and subsequent early embryonic development when using standard extenders. Indeed, an optimal semen extender must not only regulate and support an environment of adequate pH and buffering capacity to protect spermatozoa from osmotic and cooling stresses, but, also prevent the generation and/or scavenge excess ROS. To improve ram semen liquid storage, several methods have been developed with the supplementation of extenders with antioxidants or antioxidant like-compounds (enzymes, amino-acids, vitamins, plant extracts), seminal plasma, sugars, fatty acids, and nanoparticles being a relevant approach. Promising results have been registered with the supplementation of extenders with these compounds, confirming they can be used to preserve ram semen quality and fertility. Therefore, the present review provides an updated overview of the damages and associated mechanisms that ram spermatozoa undergo during liquid storage. Moreover, the supplementation of extenders with different compounds as a tool to improve semen storage is also discussed as well as their efficiency to reduce and/or prevent sperm damages during storage.</span>
文摘The solid oxide electrolyte galvanic cell represented by Mo/Cr,Cr_2O_3//ZrO_2(MgO)//[O], Ce_2O_2S/Mo+ZrO_2 ceramic-metal,Mo have been used to study the thermodynamic proper- ties of Fe-Nb-Ce solution containing trace carbon at 1600℃.The equilibrium constant for the reaction Ce_2O_2S=2[Ce]+2[O]+[S] and the standard free energy of formation of Ce_2O_2S have been determined in liquid iron at 1600℃ as K=4.395×10^(-15).ΔG_(Ce_2)O_2S=-514.786 kJ·mol^(-1).The interaction coefficients between cerium and niobium are found to he e_(Nd)^(Ce)=-2.306,e_(Nd)^(Ce)=-3.481. The equilibrium products began to contain the compound NbC with the increase of Nh concentration in the condition of trace carbon.The formation of NbC is discussed in this work.The standard free energy of formation of NbC in liquid iron at 1600℃ have been de- termined as ΔG_(NbC)=-87.111 kJ·mol^(-1).
基金funded by a NASA Grant NNX13AF46Apartly by the National Institute for Occupational Safety and Health through the UC Pilot Research Project Training Program ERC Grant #T42OH008432
文摘Dry-spun Carbon Nanotube(CNT)fibers were surface-modified by atmospheric pressure oxygen plasma functionalization using a well controlled and continuous process.The fibers were characterized by scanning electron microscopy(SEM),Raman spectroscopy,and X-ray Photoelectron Spectroscopy(XPS).It was found from the conducted electrochemical measurements that the functionalized fibers showed a 132.8% increase in specific capacitance compared to non-functionalized fibers.Dye-adsorption test and the obtained Randles-Sevcik plot demonstrated that the oxygen plasma functionalized fibers exhibited increased surface area.It was further established by Brunauer-Emmett-Teller(BET)measurements that the surface area of the CNT fibers was increased from 168.22 m^2/g to 208.01 m^2/g after plasma functionalization.The pore size distribution of the fibers was also altered by this processing.The improved electrochemical data was attributed to enhanced wettability,increased surface area,and the presence of oxygen functional groups,which promoted the capacitance of the fibers.Fiber supercapacitors were fabricated from the oxygen plasma functionalized CNT fiber electrodes using different electrolyte systems.The devices with functionalized electrodes exhibited excellent cyclic stability(93.2% after 4000 cycles),flexibility,bendability,and good energy densities.At 0.5 m A/cm^2,the EMIMBF4 device revealed a specific capacitance,which is 27% and 65%greater than the specific capacitances of devices using EMIMTFSI and H2SO4 electrolytes,respectively.The practiced in this work plasma surface processing can be employed in other applications where fibers,yarns,ribbons,and sheets need to be chemically modified.
文摘A mechanism of oxygen transportation in Czochralski growth of silicon crystals under a horizontal magnetic field (HMCZ) is proposed. Oxygen depleted surface melt, driven to the growth interface by the thermal Marangoni flow, determines oxygen concentration in the grown crystals. Systematic study was carried out to investigate effects of growth parameters on oxygen incorporation into crystals.
