The progress in our understanding of the endogenous protein concept over the past century is reviewed.Nondietary proteins found in the digesta at the terminal ileum of poultry,known as endogenous protein loss,are comp...The progress in our understanding of the endogenous protein concept over the past century is reviewed.Nondietary proteins found in the digesta at the terminal ileum of poultry,known as endogenous protein loss,are comprised of digestive secretions,mucus and sloughed gut epithelial cells.The measurement of this loss is of fundamental importance because it is an indicator of gut metabolism and is essential to adjust apparent estimates of ileal amino acid digestibility.The ileal endogenous amino acid losses comprise of two components,namely basal and specific losses.The basal losses are fixed and associated with feed dry matter intake,whereas the specific losses are variable and induced by the presence of dietary components such as fibre and anti-nutrients.Currently there is no methodology available to directly measure the specific endogenous losses and these losses are calculated by determining the basal and total(basal plus specific)losses and,then subtracting the basal losses from total losses.The seminal features,specific applications and shortcomings of available methodologies are briefly outlined as well as the practical challenges faced in using the published endogenous amino acid loss values for true digestibility corrections.The relevance of taurine as a component of endogenous protein flow in poultry is identified for the first time.展开更多
Chronic rejection(CR)of liver allografts causes damage to intrahepatic vessels and bile ducts and may lead to graft failure after liver transplantation.Although its prevalence has declined steadily with the introducti...Chronic rejection(CR)of liver allografts causes damage to intrahepatic vessels and bile ducts and may lead to graft failure after liver transplantation.Although its prevalence has declined steadily with the introduction of potent immunosuppressive therapy,CR still represents an important cause of graft injury,which might be irreversible,leading to graft loss requiring re-transplantation.To date,we still do not fully appreciate the mechanisms underlying this process.In addition to T cell-mediated CR,which was initially the only recognized type of CR,recently a new form of liver allograft CR,antibody-mediated CR,has been identified.This has indeed opened an era of thriving research and renewed interest in the field.Liver biopsy is needed for a definitive diagnosis of CR,but current research is aiming to identify new non-invasive tools for predicting patients at risk for CR after liver transplantation.Moreover,the minimization or withdrawal of immunosuppressive therapy might influence the establishment of subclinical CR-related injury,which should not be disregarded.Therapies for CR may only be effective in the“early”phases,and a tailored management of the immunosuppression regimen is essential for preventing irreversible liver damage.Herein,we provide an overview of the current knowledge and research on CR,focusing on early detection,identification of non-invasive biomarkers,immunosuppressive management,re-transplantation and future perspectives of CR.展开更多
The flow and heat transfer characteristics inside a rectangular channel embedded with pin fins were numerically and experimentally investigated.Several differently shaped pin fins(i.e.,circular,elliptical,and drop-sha...The flow and heat transfer characteristics inside a rectangular channel embedded with pin fins were numerically and experimentally investigated.Several differently shaped pin fins(i.e.,circular,elliptical,and drop-shaped)with the same cross-sectional areas were compared in a staggered arrangement.The Reynolds number based on the obstructed section hydraulic diameter(defined as the ratio of the total wetted surface area to the open duct volume available for flow)was varied from 4800 to 8200.The more streamlined drop-shaped pin fins were better at delaying or suppressing separation of the flow passing through them,which decreased the aerodynamic penalty compared to circular pin fins.The heat transfer enhancement of the drop-shaped pin fins was less than that of the circular pin fins.In terms of specific performance parameters,drop-shaped pin fins are a promising alternative configuration to circular pin fins.展开更多
The identification of deuterons with momenta in the range of 0.52−0.72 GeV/c is studied with specific ionization energy loss information using a data sample collected by the BESIII detector at center-of-mass energies ...The identification of deuterons with momenta in the range of 0.52−0.72 GeV/c is studied with specific ionization energy loss information using a data sample collected by the BESIII detector at center-of-mass energies between 4.009 and 4.946 GeV.Clean deuteron samples are selected using time of flight information.For all data samples,the deuteron identification efficiencies are higher than 95%,with a maximum difference of%between data and Monte Carlo simulation.This verifies the effectiveness of the deuteron identification method based on specific ionization energy loss and provides valuable information for future studies on processes involving deuterons in the final state at BESIII.展开更多
An optimized silicon carbide(SiC)trench metal-oxide-semiconductor field-effect transistor(MOSFET)structure with side-wall p-type pillar(p-pillar)and wrap n-type pillar(n-pillar)in the n-drain was investigated by utili...An optimized silicon carbide(SiC)trench metal-oxide-semiconductor field-effect transistor(MOSFET)structure with side-wall p-type pillar(p-pillar)and wrap n-type pillar(n-pillar)in the n-drain was investigated by utilizing Silvaco TCAD simulations.The optimized structure mainly includes a p+buried region,a light n-type current spreading layer(CSL),a p-type pillar region,and a wrapping n-type pillar region at the right and bottom of the p-pillar.The improved structure is named as SNPPT-MOS.The side-wall p-pillar region could better relieve the high electric field around the p+shielding region and the gate oxide in the off-state mode.The wrapping n-pillar region and CSL can also effectively reduce the specific on-resistance(Ron,sp).As a result,the SNPPT-MOS structure exhibits that the figure of merit(Fo M)related to the breakdown voltage(V_(BR))and Ron,sp(V_(BR)^2R_(on,sp))of the SNPPT-MOS is improved by 44.5%,in comparison to that of the conventional trench gate SJ MOSFET(full-SJ-MOS).In addition,the SNPPT-MOS structure achieves a much fasterwitching speed than the full-SJ-MOS,and the result indicates an appreciable reduction in the switching energy loss.展开更多
Harmful algal blooms in eutrophic waters pose a serious threat to freshwater ecosystems and human health. In-situ light availability control is one of the most commonly used technologies to suppress algae in lakes and...Harmful algal blooms in eutrophic waters pose a serious threat to freshwater ecosystems and human health. In-situ light availability control is one of the most commonly used technologies to suppress algae in lakes and reservoirs. To develop a better understanding of the effects of light on algal growth, specific density, colony size and sinking loss, Anabaena flos-aquae(cyanobacteria) and Scenedesmus obliquus(green algae) were evaluated in varying light scenarios. The results showed that the specific density and colony size of these two species varied during growth, and there were obvious differences among the light scenarios. At the end of exponential phase, S. obliquus incubated under light-limited condition maintained a higher specific density and formed larger aggregates, whereas A. flos-aquae formed a longer filament length. Both species exhibited higher sinking loss rates with lower light availability. These results implied that the sinking loss rate was not always constant but should be considered as a variable response to the change of light availability, and in-situ light availability control might result in a significant increase of the sinking loss of algae due to the change of size and specific density, thereby further affecting the algal biomass in the water column.展开更多
This article investigates an improved 4H-SiC trench gate metal–oxide–semiconductor field-effect transistor(MOSFET)(UMOSFET)fitted with a super-junction(SJ)shielded region.The modified structure is composed of two n-...This article investigates an improved 4H-SiC trench gate metal–oxide–semiconductor field-effect transistor(MOSFET)(UMOSFET)fitted with a super-junction(SJ)shielded region.The modified structure is composed of two n-type conductive pillars,three p-type conductive pillars,an oxide trench under the gate,and a light n-type current spreading layer(NCSL)under the p-body.The n-type conductive pillars and the light n-type current spreading layer provide two paths to and promote the diffusion of a transverse current in the epitaxial layer,thus improving the specific on-resistance(R_(on,sp)).There are three p-type pillars in the modified structure,with the p-type pillars on both sides playing the same role.The p-type conductive pillars relieve the electric field(E-field)in the corner of the trench bottom.Two-dimensional simulation(silvaco TCAD)indicates that Ron,sp of the modified structure,and breakdown voltage(V_(BR))are improved by 22.2%and 21.1%respectively,while the maximum figure of merit(FOM=V_(BR)^(2)/R_(on,sp)) is improved by 79.0%.Furthermore,the improved structure achieves a light smaller low gate-to-drain charge(Q_(gd))and when compared with the conventional UMOSFET(conventional-UMOS),it displays great advantages for reducing the switching energy loss.These advantages are due to the fact that the p-type conductive pillars and n-type conductive pillars configured under the gate provide a substantial charge balance,which also enables the charge carriers to be extracted quickly.In the end,under the condition of the same total charge quantity,the simulation comparison of gate charge and OFF-state characteristics between Gaussdoped structure and uniform-doped structure shows that Gauss-doped structure increases the V_(BR)of the device without degradation of dynamic performance.展开更多
We established the thermodynamic analysis model by using the actual measurement parameters of 600 MW direct dry cooling power plant in Wuxiang, China. The performance, especially the exergy losses of the unit as well ...We established the thermodynamic analysis model by using the actual measurement parameters of 600 MW direct dry cooling power plant in Wuxiang, China. The performance, especially the exergy losses of the unit as well as its subsystems mainly including seven parts were obtained not only at one specific load but also at different loads. We have found that the exergy loss in the boiler is usually more than 70% of the total exergy loss of the system, while the exergy loss of the combustion occupies greater than 50% of that of the boiler. Therefore, it is crucial to reduce the losses in the boiler for energy saving potential improvement, especially that of the combustion and heat transfer. At the same time, the cold end optimization has relatively large potential for energy saving due to that the exergy efficiency of the air cooling system is quite low being about 5.7% or so. In addition, we have gotten the main changing trends of system performances along with the load change, including exergy loss, exergy efficiency and coal consumption, which were derived from the real-time system performance statistics according to a large amount of measured data in real time. In order to make the whole system run more efficiently, it is advised that the unit should run at the load better than 350 MW.展开更多
For proper water management in the new reclaimed areas, hydraulic parameters of both aquifer and wells related to transmissivity, specific capacity, well loss, formation loss, and water entrance velocity, as well as t...For proper water management in the new reclaimed areas, hydraulic parameters of both aquifer and wells related to transmissivity, specific capacity, well loss, formation loss, and water entrance velocity, as well as the relationship between these parameters are the main target after construction of production wells. In El Shab area, the Nubian Sandstone aquifer has a large range of transmissivity (from 483.12 to 1489.24 m2/day) and, also, specific capacity (from 203 to 486.32 m2/day). Relationship of specific capacity and transmissivity is constructed and the established empirical equations can be used to predict the transmissivity of the Nubian aquifer in all new proposed sites for well drilling at which the specific capacity measured without performing pumping tests. On the other hand, the drilled wells in El Shab area exhibit relatively high well losses (25%). The causes for high well losses (entrance velocity (Vn) through water well screen and the distance from the point of water entrance in the well to the point of intake in the pump) are discussed and the relationships are constructed, which seem a positive linear correlation. Relationships between well losses constant for 30 wells with transmissivity and specific capacity, are constructed. These relationships are useful for estimating hydraulic characteristics that are needed for the designs of wells and well fields and for preliminary water-resources management.展开更多
A 4H-SiC trench gate metal-oxide-semiconductor field-effect transistor(UMOSFET)with semi-super-junction shiel-ded structure(SS-UMOS)is proposed and compared with conventional trench MOSFET(CT-UMOS)in this work.The adv...A 4H-SiC trench gate metal-oxide-semiconductor field-effect transistor(UMOSFET)with semi-super-junction shiel-ded structure(SS-UMOS)is proposed and compared with conventional trench MOSFET(CT-UMOS)in this work.The advantage of the proposed structure is given by comprehensive study of the mechanism of the local semi-super-junction structure at the bottom of the trench MOSFET.In particular,the influence of the bias condition of the p-pillar at the bottom of the trench on the static and dynamic performances of the device is compared and revealed.The on-resistance of SS-UMOS with grounded(G)and ungrounded(NG)p-pillar is reduced by 52%(G)and 71%(NG)compared to CT-UMOS,respectively.Additionally,gate ox-ide in the GSS-UMOS is fully protected by the p-shield layer as well as semi-super-junction structure under the trench and p-base regions.Thus,a reduced electric-field of 2 MV/cm can be achieved at the corner of the p-shield layer.However,the quasi-intrinsic protective layer cannot be formed in NGSS-UMOS due to the charge storage effect in the floating p-pillar,resulting in a large electric field of 2.7 MV/cm at the gate oxide layer.Moreover,the total switching loss of GSS-UMOS is 1.95 mJ/cm2 and is reduced by 18%compared with CT-UMOS.On the contrary,the NGSS-UMOS has the slowest overall switching speed due to the weakened shielding effect of the p-pillar and the largest gate-to-drain capacitance among the three.The proposed GSS-UMOS plays an important role in high-voltage and high-frequency applications,and will provide a valuable idea for device design and circuit applications.展开更多
文摘The progress in our understanding of the endogenous protein concept over the past century is reviewed.Nondietary proteins found in the digesta at the terminal ileum of poultry,known as endogenous protein loss,are comprised of digestive secretions,mucus and sloughed gut epithelial cells.The measurement of this loss is of fundamental importance because it is an indicator of gut metabolism and is essential to adjust apparent estimates of ileal amino acid digestibility.The ileal endogenous amino acid losses comprise of two components,namely basal and specific losses.The basal losses are fixed and associated with feed dry matter intake,whereas the specific losses are variable and induced by the presence of dietary components such as fibre and anti-nutrients.Currently there is no methodology available to directly measure the specific endogenous losses and these losses are calculated by determining the basal and total(basal plus specific)losses and,then subtracting the basal losses from total losses.The seminal features,specific applications and shortcomings of available methodologies are briefly outlined as well as the practical challenges faced in using the published endogenous amino acid loss values for true digestibility corrections.The relevance of taurine as a component of endogenous protein flow in poultry is identified for the first time.
文摘Chronic rejection(CR)of liver allografts causes damage to intrahepatic vessels and bile ducts and may lead to graft failure after liver transplantation.Although its prevalence has declined steadily with the introduction of potent immunosuppressive therapy,CR still represents an important cause of graft injury,which might be irreversible,leading to graft loss requiring re-transplantation.To date,we still do not fully appreciate the mechanisms underlying this process.In addition to T cell-mediated CR,which was initially the only recognized type of CR,recently a new form of liver allograft CR,antibody-mediated CR,has been identified.This has indeed opened an era of thriving research and renewed interest in the field.Liver biopsy is needed for a definitive diagnosis of CR,but current research is aiming to identify new non-invasive tools for predicting patients at risk for CR after liver transplantation.Moreover,the minimization or withdrawal of immunosuppressive therapy might influence the establishment of subclinical CR-related injury,which should not be disregarded.Therapies for CR may only be effective in the“early”phases,and a tailored management of the immunosuppression regimen is essential for preventing irreversible liver damage.Herein,we provide an overview of the current knowledge and research on CR,focusing on early detection,identification of non-invasive biomarkers,immunosuppressive management,re-transplantation and future perspectives of CR.
基金the National Natural Science Foundation of China(Grant no.51276090)for this project.
文摘The flow and heat transfer characteristics inside a rectangular channel embedded with pin fins were numerically and experimentally investigated.Several differently shaped pin fins(i.e.,circular,elliptical,and drop-shaped)with the same cross-sectional areas were compared in a staggered arrangement.The Reynolds number based on the obstructed section hydraulic diameter(defined as the ratio of the total wetted surface area to the open duct volume available for flow)was varied from 4800 to 8200.The more streamlined drop-shaped pin fins were better at delaying or suppressing separation of the flow passing through them,which decreased the aerodynamic penalty compared to circular pin fins.The heat transfer enhancement of the drop-shaped pin fins was less than that of the circular pin fins.In terms of specific performance parameters,drop-shaped pin fins are a promising alternative configuration to circular pin fins.
基金Supported by the National Natural Science Foundation of China(11975118,12205141,12375071)。
文摘The identification of deuterons with momenta in the range of 0.52−0.72 GeV/c is studied with specific ionization energy loss information using a data sample collected by the BESIII detector at center-of-mass energies between 4.009 and 4.946 GeV.Clean deuteron samples are selected using time of flight information.For all data samples,the deuteron identification efficiencies are higher than 95%,with a maximum difference of%between data and Monte Carlo simulation.This verifies the effectiveness of the deuteron identification method based on specific ionization energy loss and provides valuable information for future studies on processes involving deuterons in the final state at BESIII.
基金the National Natural Science Foundation of China(Grant Nos.61774052 and 61904045)the National Natural Science Foundation of Jiangxi Province of China(Grant No.20202BABL201021)the Education Department of Jiangxi Province of China for Youth Foundation(Grant No.GJJ191154)。
文摘An optimized silicon carbide(SiC)trench metal-oxide-semiconductor field-effect transistor(MOSFET)structure with side-wall p-type pillar(p-pillar)and wrap n-type pillar(n-pillar)in the n-drain was investigated by utilizing Silvaco TCAD simulations.The optimized structure mainly includes a p+buried region,a light n-type current spreading layer(CSL),a p-type pillar region,and a wrapping n-type pillar region at the right and bottom of the p-pillar.The improved structure is named as SNPPT-MOS.The side-wall p-pillar region could better relieve the high electric field around the p+shielding region and the gate oxide in the off-state mode.The wrapping n-pillar region and CSL can also effectively reduce the specific on-resistance(Ron,sp).As a result,the SNPPT-MOS structure exhibits that the figure of merit(Fo M)related to the breakdown voltage(V_(BR))and Ron,sp(V_(BR)^2R_(on,sp))of the SNPPT-MOS is improved by 44.5%,in comparison to that of the conventional trench gate SJ MOSFET(full-SJ-MOS).In addition,the SNPPT-MOS structure achieves a much fasterwitching speed than the full-SJ-MOS,and the result indicates an appreciable reduction in the switching energy loss.
基金Supported by the National Natural Science Foundation of China(No.41471393)the Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration(No.SHUES2016B03)
文摘Harmful algal blooms in eutrophic waters pose a serious threat to freshwater ecosystems and human health. In-situ light availability control is one of the most commonly used technologies to suppress algae in lakes and reservoirs. To develop a better understanding of the effects of light on algal growth, specific density, colony size and sinking loss, Anabaena flos-aquae(cyanobacteria) and Scenedesmus obliquus(green algae) were evaluated in varying light scenarios. The results showed that the specific density and colony size of these two species varied during growth, and there were obvious differences among the light scenarios. At the end of exponential phase, S. obliquus incubated under light-limited condition maintained a higher specific density and formed larger aggregates, whereas A. flos-aquae formed a longer filament length. Both species exhibited higher sinking loss rates with lower light availability. These results implied that the sinking loss rate was not always constant but should be considered as a variable response to the change of light availability, and in-situ light availability control might result in a significant increase of the sinking loss of algae due to the change of size and specific density, thereby further affecting the algal biomass in the water column.
基金the National Natural Science Foundation of China(Grant Nos.61774052 and 61904045)the Youth Foundation of the Education Department of Jiangxi Province,China(Grant No.GJJ191154)the Youth Foundation of Ping Xiang University,China(Grant No.2018D0230).
文摘This article investigates an improved 4H-SiC trench gate metal–oxide–semiconductor field-effect transistor(MOSFET)(UMOSFET)fitted with a super-junction(SJ)shielded region.The modified structure is composed of two n-type conductive pillars,three p-type conductive pillars,an oxide trench under the gate,and a light n-type current spreading layer(NCSL)under the p-body.The n-type conductive pillars and the light n-type current spreading layer provide two paths to and promote the diffusion of a transverse current in the epitaxial layer,thus improving the specific on-resistance(R_(on,sp)).There are three p-type pillars in the modified structure,with the p-type pillars on both sides playing the same role.The p-type conductive pillars relieve the electric field(E-field)in the corner of the trench bottom.Two-dimensional simulation(silvaco TCAD)indicates that Ron,sp of the modified structure,and breakdown voltage(V_(BR))are improved by 22.2%and 21.1%respectively,while the maximum figure of merit(FOM=V_(BR)^(2)/R_(on,sp)) is improved by 79.0%.Furthermore,the improved structure achieves a light smaller low gate-to-drain charge(Q_(gd))and when compared with the conventional UMOSFET(conventional-UMOS),it displays great advantages for reducing the switching energy loss.These advantages are due to the fact that the p-type conductive pillars and n-type conductive pillars configured under the gate provide a substantial charge balance,which also enables the charge carriers to be extracted quickly.In the end,under the condition of the same total charge quantity,the simulation comparison of gate charge and OFF-state characteristics between Gaussdoped structure and uniform-doped structure shows that Gauss-doped structure increases the V_(BR)of the device without degradation of dynamic performance.
文摘We established the thermodynamic analysis model by using the actual measurement parameters of 600 MW direct dry cooling power plant in Wuxiang, China. The performance, especially the exergy losses of the unit as well as its subsystems mainly including seven parts were obtained not only at one specific load but also at different loads. We have found that the exergy loss in the boiler is usually more than 70% of the total exergy loss of the system, while the exergy loss of the combustion occupies greater than 50% of that of the boiler. Therefore, it is crucial to reduce the losses in the boiler for energy saving potential improvement, especially that of the combustion and heat transfer. At the same time, the cold end optimization has relatively large potential for energy saving due to that the exergy efficiency of the air cooling system is quite low being about 5.7% or so. In addition, we have gotten the main changing trends of system performances along with the load change, including exergy loss, exergy efficiency and coal consumption, which were derived from the real-time system performance statistics according to a large amount of measured data in real time. In order to make the whole system run more efficiently, it is advised that the unit should run at the load better than 350 MW.
文摘For proper water management in the new reclaimed areas, hydraulic parameters of both aquifer and wells related to transmissivity, specific capacity, well loss, formation loss, and water entrance velocity, as well as the relationship between these parameters are the main target after construction of production wells. In El Shab area, the Nubian Sandstone aquifer has a large range of transmissivity (from 483.12 to 1489.24 m2/day) and, also, specific capacity (from 203 to 486.32 m2/day). Relationship of specific capacity and transmissivity is constructed and the established empirical equations can be used to predict the transmissivity of the Nubian aquifer in all new proposed sites for well drilling at which the specific capacity measured without performing pumping tests. On the other hand, the drilled wells in El Shab area exhibit relatively high well losses (25%). The causes for high well losses (entrance velocity (Vn) through water well screen and the distance from the point of water entrance in the well to the point of intake in the pump) are discussed and the relationships are constructed, which seem a positive linear correlation. Relationships between well losses constant for 30 wells with transmissivity and specific capacity, are constructed. These relationships are useful for estimating hydraulic characteristics that are needed for the designs of wells and well fields and for preliminary water-resources management.
基金supported by the National Natural Science Foundation of China(Grant No.62104222)the Natural Science Foundation of Fujian Province of China for Distinguished Young Scholars(Grant No.2020J06002)+3 种基金the Science and Technology Project of Fujian Province of China(Grant No.2020I0001)the Science and Technology Key Projects of Xiamen(Grant No.3502ZCQ20191001)Shenzhen Science and Technology Program(Grant No.JSGG20201102-155800003)Jiangxi Provincial Natural Science Foundation(Grant No.20212ACB212005).
文摘A 4H-SiC trench gate metal-oxide-semiconductor field-effect transistor(UMOSFET)with semi-super-junction shiel-ded structure(SS-UMOS)is proposed and compared with conventional trench MOSFET(CT-UMOS)in this work.The advantage of the proposed structure is given by comprehensive study of the mechanism of the local semi-super-junction structure at the bottom of the trench MOSFET.In particular,the influence of the bias condition of the p-pillar at the bottom of the trench on the static and dynamic performances of the device is compared and revealed.The on-resistance of SS-UMOS with grounded(G)and ungrounded(NG)p-pillar is reduced by 52%(G)and 71%(NG)compared to CT-UMOS,respectively.Additionally,gate ox-ide in the GSS-UMOS is fully protected by the p-shield layer as well as semi-super-junction structure under the trench and p-base regions.Thus,a reduced electric-field of 2 MV/cm can be achieved at the corner of the p-shield layer.However,the quasi-intrinsic protective layer cannot be formed in NGSS-UMOS due to the charge storage effect in the floating p-pillar,resulting in a large electric field of 2.7 MV/cm at the gate oxide layer.Moreover,the total switching loss of GSS-UMOS is 1.95 mJ/cm2 and is reduced by 18%compared with CT-UMOS.On the contrary,the NGSS-UMOS has the slowest overall switching speed due to the weakened shielding effect of the p-pillar and the largest gate-to-drain capacitance among the three.The proposed GSS-UMOS plays an important role in high-voltage and high-frequency applications,and will provide a valuable idea for device design and circuit applications.
