The classification, characteristics and current situation of aluminum melt hydrogen-removal methods and technologies have been summarized. The latest studies and research results of aluminum melt degassing technology ...The classification, characteristics and current situation of aluminum melt hydrogen-removal methods and technologies have been summarized. The latest studies and research results of aluminum melt degassing technology have been summed up. The tendency and prospect of aluminum degassing technology was discussed.展开更多
The corrosion behavior of Mg-10Gd-xZn(x=2,6 wt.%)alloys in 0.5 wt.%NaCl solution was investigated.Microstructures of both the alloys consisted of(Mg,Zn)_(3) Gd phase and lamellar long period stacking ordered(LPSO)phas...The corrosion behavior of Mg-10Gd-xZn(x=2,6 wt.%)alloys in 0.5 wt.%NaCl solution was investigated.Microstructures of both the alloys consisted of(Mg,Zn)_(3) Gd phase and lamellar long period stacking ordered(LPSO)phase.The morphology of the second phase at the grain boundary differed in both alloys:it was a continuous network structure in Mg-10Gd-6Zn,whereas it was relatively discrete in Mg-10Gd-2Zn.The dendrites were finer in size and highly branched in Mg-10Gd-6Zn.The corrosion results indicated that the increase in Zn content increased the corrosion rate in Mg-10Gd-xZn alloys.Micro-galvanic corrosion occurred near the grain boundary in both alloys initially as the grain boundary phase was stable and acted as a cathode,however,filiform corrosion dominated in the later stage,which was facilitated by the LPSO phase in the matrix.Severe micro-galvanic corrosion occurred in Mg-10Gd-6Zn due to the higher volume of second phase.The stability of the second phase at the grain boundary was altered and dissolved after the long immersion times.Probably the NaCl solution chemically reacted with the grain boundary phase and de-stabilized it during the long immersion times,and was removed by the chromic acid used for the corrosion product removal.展开更多
A hallmark of all forms of neurodegenerative diseases is impairment of neuronal functions,and in many cases neuronal cell death.Although the etiology of neurodegenerative diseases may be distinct,different diseases di...A hallmark of all forms of neurodegenerative diseases is impairment of neuronal functions,and in many cases neuronal cell death.Although the etiology of neurodegenerative diseases may be distinct,different diseases display a similar pathogenesis,for example abnormal immunity within the central nervous system(CNS),activation of macrophage/microglia and the involvement of proinflammatory cytokines.Recent studies show that neurons in a neurodegenerative state undergo a highly regulated programmed cell death,also called apoptosis.TNF-related apoptosis-inducing ligand(TRAIL),a member of the TNF family,has been shown to be involved in apoptosis during many diseases.As one member of a death ligand family,TRAIL was originally thought to target only tumor cells and was not present in CNS.However,recent data showed that TRAIL was unregulated in HIV-1-infected and immune-activated macrophages,a major disease inducing cell during HIV-1-assoeiated dementia(HAD).TRAIL is also induced on neuron by β-amyloid protein,an important pathogen for Alzheimer's disease.In this review,we summarize the possible common aspects that TRAIL involved those neurodegenerative diseases,TRAIL induced apoptosis signaling in the CNS cells,and specific role of TRAIL in individual diseases.Cellular & Molecular Immunology.2005;2(2):113-122.展开更多
The insensitivity of semiconductors to visible and infrared light is a key constraint on the utilization of light energy in photocatalytic reactions.Constructing photocatalysts with full-spectrum absorption through su...The insensitivity of semiconductors to visible and infrared light is a key constraint on the utilization of light energy in photocatalytic reactions.Constructing photocatalysts with full-spectrum absorption through surface engineering is an effective approach to fully harnessing light energy in semiconductor materials.Herein,a novel stable Ti_(3)C_(2)T_(x)MXene/CdS heterojunction catalyst is obtained by in-situ epitaxial growth of two-dimensional(2D)CdS nanosheets on 2D MXene interface via a solvothermal method.The exceptional light absorption properties of MXene confer outstanding full-spectrum driven photocat-alytic hydrogen evolution capability upon the heterogeneous catalyst.The unique 2D/2D structure effectively mitigated the recombination of photogenerated carriers,enhancing the photocatalytic performance of the catalyst.Moreover,the composite catalyst exhibits a significantly higher surface temperature of 80.4℃under visible light irradiation at an intensity of 0.1 W/cm^(2),which is 1.84 times higher than that of CdS.Under irradiation of visible and near infrared light,the composite catalyst with photothermal ef-fect demonstrates a remarkable hydrogen evolution rate of 65.4 mmol g^(-1)h^(-1),which is 7.2 times higher than that of CdS catalyst.This study introduces a novel approach for constructing full-spectrum absorption catalysts and expands the application of the photothermal effect in photocatalytic hydrogen evolution research.展开更多
Following our earlier work on tomographic reconstruction of the magnetosheath soft X-ray emissions with superposed epoch analysis of many images recorded from a single spacecraft we now explore the instantaneous recon...Following our earlier work on tomographic reconstruction of the magnetosheath soft X-ray emissions with superposed epoch analysis of many images recorded from a single spacecraft we now explore the instantaneous reconstruction of the magnetosheath and magnetopause using a few images recorded simultaneously from a few spacecraft.This work is motivated by the prospect of possibly having two or three soft X-ray imagers in space in the coming years,and that many phenomena which occur at the magnetopause boundary,such as reconnection events and pressure pulse responses,do not lend themselves as well to superposed epoch analysis.If the reconstruction is successful-which we demonstrate in this paper that it can be-this collection of imagers can be used to reconstruct the magnetosheath and magnetopause from a single image from each spacecraft,allowing for high time resolution reconstructions.In this paper we explore the reconstruction using,two,three,and four spacecraft.We show that the location of the subsolar point of the magnetopause can be determined with just two satellites,and that volume emissions of soft X-rays,and the shape of the boundary,can be reconstructed using three or more satellites.展开更多
Background:Alzheimer’s disease(AD)is a fatal disease that threatens the quality of life of an aging population at a global scale.Various hypotheses on the etiology of AD have been developed over the years to guide ef...Background:Alzheimer’s disease(AD)is a fatal disease that threatens the quality of life of an aging population at a global scale.Various hypotheses on the etiology of AD have been developed over the years to guide efforts in search of therapeutic strategies.Main body:In this review,we focus on four AD hypotheses currently relevant to AD onset:the prevailing amyloid cascade hypothesis,the well-recognized tau hypothesis,the increasingly popular pathogen(viral infection)hypothesis,and the infection-related antimicrobial protection hypothesis.In briefly reviewing the main evidence supporting each hypothesis and discussing the questions that need to be addressed,we hope to gain a better understanding of the complicated multi-layered interactions in potential causal and/or risk factors in AD pathogenesis.As a defining feature of AD,the existence of amyloid deposits is likely fundamental to AD onset but is insufficient to wholly reproduce many complexities of the disorder.A similar belief is currently also applied to hyperphosphorylated tau aggregates within neurons,where tau has been postulated to drive neurodegeneration in the presence of pre-existing Aβplaques in the brain.Although infection of the central nerve system by pathogens such as viruses may increase AD risk,it is yet to be determined whether this phenomenon is applicable to all cases of sporadic AD and whether it is a primary trigger for AD onset.Lastly,the antimicrobial protection hypothesis provides insight into a potential physiological role for Aβpeptides,but how Aβ/microbial interactions affect AD pathogenesis during aging awaits further validation.Nevertheless,this hypothesis cautions potential adverse effects in Aβ-targeting therapies by hindering potential roles for Aβin anti-viral protection.Conclusion:AD is a multi-factor complex disorder,which likely requires a combinatorial therapeutic approach to successfully slow or reduce symptomatic memory decline.A better understanding of how various causal and/or risk factors affecting disease onse展开更多
A single phase brushless spindle motor with innovative design has been developed for application in a DVD drive. The methods used to reduce the cogging torque and to improve the dynamic performance of this new design ...A single phase brushless spindle motor with innovative design has been developed for application in a DVD drive. The methods used to reduce the cogging torque and to improve the dynamic performance of this new design motor are proposed in this paper. The single phase brushless spindle motor is usually applied for cooling fan, pump and blower before the performance is improved by the reengineering process. The stator configuration and the drive circuit have been remodeled in order to meet the requirements of the spindle motor used in the DVD applications.展开更多
Arteriovenous fistulas(AVFs)are a vital form of AV access for patients requiring hemodialysis,but they link to overall morbidity and mortality when they fail to mature.The most common cause of AVF non-maturation is ne...Arteriovenous fistulas(AVFs)are a vital form of AV access for patients requiring hemodialysis,but they link to overall morbidity and mortality when they fail to mature.The most common cause of AVF non-maturation is neointimal hyperplasia(NIH).To minimize the deleterious effects of NIH,a perivascular wrap composed of polycaprolactone(PCL),rosuvastatin(ROSU),and gold nanoparticles(AUNPs)was constructed.This study assessed the impact of ROSU-eluting,radiopaque resorbable perivascular wraps on pathologic NIH in a chronic kidney disease(CKD)rodent model of AVF.Electrospun PCL wraps containing AuNPs and/or ROSU were monitored for in vitro tensile strength,AuNP release,ROSU elution,and effect on cellular viability.The wraps were then implanted around an AVF in a CKD rodent model for in vivo ultrasound(US)and micro-computed tomography(mCT)imaging.AVF specimens were collected for histological analyses.Cell viability was preserved in the presence of both AuNP-and ROSU-containing wraps.In vitro release of ROSU and AuNPs correlated with in vivo findings of decreasing radiopacity on mCT over time.AuNP-loaded wraps had higher radiopacity(1270.0-1412.0 HU at week 2)compared with other wraps(103.5-456.0 HU),which decreased over time.The addition of ROSU decreased US and histologic measurements of NIH.The reduced NIH seen with ROSU-loaded perivascular wraps suggests a synergistic effect between mechanical support and anti-hyperplasia medication.Furthermore,AuNP loading increased wrap radiopacity.Together,our results show that AuNP-and ROSU-loaded PCL wraps induce AVF maturation and suppress NIH while facilitating optimal implanted device visualization.展开更多
Powder metallurgy is an efficient approach to fabricate varieties of high performance structure materials, function materials and special materials working under limited conditions. Research and development of new eff...Powder metallurgy is an efficient approach to fabricate varieties of high performance structure materials, function materials and special materials working under limited conditions. Research and development of new efficient technology to form high-density, high-performance and net shape parts is a key to widen application and development of powder materials. Recently, the low-voltage electromagnetic compaction (EMC) has been used by present authors to compacted copper, tin, aluminum powders and the products with 99% relative density have been acquired. In this work, the research has been extended to investigation on the density uniformity of pressed parts. The analysis results show that the density of the part compacted by low-voltage EMC decreases gradually in press direction as static compaction. But it is higher and more homogeneous. The density of the top part increases gradually from the center to the outer, which is just reversal of the bottom part. In some extent, the higher the discharging voltage is, the higher the density is and the more homogeneous the distribution is. In addition, repetitive compaction can improve the density of powder parts and the distribution uniformity.展开更多
A mathematical model coupling the momentum, energy and species conservation equa-tions was proposed to calculate the macro--segregation of Fe--C alloy ingot during solid-ification. The corresponding simulation softwar...A mathematical model coupling the momentum, energy and species conservation equa-tions was proposed to calculate the macro--segregation of Fe--C alloy ingot during solid-ification. The corresponding simulation software which concurrently solves the macro-scopic mass, momentum, energy and species conservation equations has been developedby applying the SIMPLE algorithm.The thermo--solutal convection in a NH_4 Cl--H_2O ingot is verified and the result showsgood agreement with that reported. Then macro--segregation in a steel ingot is simu-lated by using the developed program. The steel ingot is in a rectangular mold with ariser. The fluid flow is mainly induced by the temperature field and the solid fraction.The macro--segregation pattern is mainly affected by the thermo--induced convectionin the mushy zone. The negative segregation forms along the walls of the casting.The positive segregation forms at the top center of the casting into the riser. Thespecies concentration reaches the peak in the center of the ingot where solidificationends lastly.展开更多
We report spectral and timing analysis of the black hole transient MAXI J1631–479 during the hard intermediate state of its 2019 outburst from the Insight-Hard X-ray Modulation Telescope(Insight-HXMT)observations.We ...We report spectral and timing analysis of the black hole transient MAXI J1631–479 during the hard intermediate state of its 2019 outburst from the Insight-Hard X-ray Modulation Telescope(Insight-HXMT)observations.We find that the energy dependence of the type-C quasi-periodic oscillation(QPO)frequency evolves with time:during the initial rise of a small flare(~MJD 58526.0-58527.1),the QPO frequency increases with increasing energy from~1 to~100 ke V,and then the frequency remains constant after MJD 58527.1.We discover a possible new phenomenon of Fe line’s QPO frequency jump that has never been observed for other black hole transients:during the small flare,the QPO frequency around the Fe line energy is higher than any other energy band,with the frequency difference Δf=0.25±0.08 Hz between 5.5–7.5 ke V and other energy bands.The spectral analysis shows that the evolution of QPOs is related to the equivalent width of the narrow Fe line,and its equivalent width increases during this small flare.We propose that the QPO frequency difference results from the differential precession of a vertically extended jet,and the higher QPO frequency of Fe line could be caused by the layered jet when the jet scale increases.At the same time,the evolution of QPOs is related to the accretion rate,while the energy dependence of QPOs supports the existence of deceleration in the vertically distributed jet.展开更多
Brain transcriptional regulatory network for behavior demonstrates that brain gene expression in the honey bee can be accurately predicted from the expression transcription factors(TFs),but roles for specific TFs are ...Brain transcriptional regulatory network for behavior demonstrates that brain gene expression in the honey bee can be accurately predicted from the expression transcription factors(TFs),but roles for specific TFs are less understood.Mushroom bodies(MBs)are important for learning,memory and sensory integration in the honey bee brain.A TFs,Mblk-1,expressed preferentially in the large-type Kenyon cells of the honeybee MBs is predicted to be involved in brain function by regulating transcription of its target genes in honey bee.However,its function and the mechanism of regulation in behavior of honey bee is still obscure.Here we show that Mblk-1 had significantly higher expression in the brains of forager bees relative to nurse bees.Mblk-1 was significantly inhibited in bees fed small interfering RNA.In addition,inhibition of Mblk-1 decreased sucrose responsiveness in foragers.Finally,we determined that Mblk-1 regulated the messenger RNA of AmGRl.These findings suggest that Mblk-1 may target AmGRl to regulate the sucrose responsiveness of foragers.展开更多
The current studies on power plant technologies suggest that Integrated Gasification Combined Cycle(IGCC)systems are an effective and economic CO_(2) capture technology pathway.In addition,the system in conventional c...The current studies on power plant technologies suggest that Integrated Gasification Combined Cycle(IGCC)systems are an effective and economic CO_(2) capture technology pathway.In addition,the system in conventional configuration has the advantage of being more“CO_(2) capture ready”than other technologies.Pulverized coal boilers(PC)have,however,proven high technical performance attributes and are economically often most practical technologies.To highlight the pros and cons of both technologies in connection with an integrated CO_(2) capture,a comparative analysis of ultrasupercritical PC and IGCC is carried out in this paper.The technical design,the mass and energy balance and the system optimizations are implemented by using the ECLIPSE chemical plant simulation software package.Built upon these technologies,the CO_(2) capture facilities are incorporated within the system.The most appropriate CO_(2) capture systems for the PC system selected for this work are the oxy-fuel system and the postcombustion scheme using Monoethanolamine solvent scrubber column(MEA).The IGCC systems are designed in two configurations:Water gas shift reactor and Selexol-based separation.Both options generate CO_(2)-rich and hydrogen rich-gas streams.Following the comparative analysis of the technical performance attributes of the above cycles,the economic assessment is carried out using the economic toolbox of ECLIPSE is seamlessly connected to the results of the mass and energy balance as well as the utility usages.The total cost assessment is implemented according to the stepcount exponential costing method using the dominant factors and/or a combination of parameters.Subsequently,based on a set of assumptions,the net present value estimation is implemented to calculate the breakeven electricity selling prices and the CO_(2) avoidance cost.展开更多
The nonlinear atomistic interactions usually involve softening behavior. Instability resulting directly from this softening are called the material instability, while those unrelated to this softening are called the s...The nonlinear atomistic interactions usually involve softening behavior. Instability resulting directly from this softening are called the material instability, while those unrelated to this softening are called the structural instability. We use the finite-deformation shell theory based on the interatomic potential to show that the tension instability of single-wall carbon nanotubes is the material instability, while the compression and torsion instabilities are structural instability.展开更多
The Low-lying excited states of HeH have been calculated by arrangement channel quantum mechanics(ACQM),The calculated potential curves,equilibrium geometry,Rc.dissociation energy Dc.harmonic vibration frequency ω0 a...The Low-lying excited states of HeH have been calculated by arrangement channel quantum mechanics(ACQM),The calculated potential curves,equilibrium geometry,Rc.dissociation energy Dc.harmonic vibration frequency ω0 and quadratic force coustant F2 are comparable with Ci calculations.展开更多
文摘The classification, characteristics and current situation of aluminum melt hydrogen-removal methods and technologies have been summarized. The latest studies and research results of aluminum melt degassing technology have been summed up. The tendency and prospect of aluminum degassing technology was discussed.
文摘The corrosion behavior of Mg-10Gd-xZn(x=2,6 wt.%)alloys in 0.5 wt.%NaCl solution was investigated.Microstructures of both the alloys consisted of(Mg,Zn)_(3) Gd phase and lamellar long period stacking ordered(LPSO)phase.The morphology of the second phase at the grain boundary differed in both alloys:it was a continuous network structure in Mg-10Gd-6Zn,whereas it was relatively discrete in Mg-10Gd-2Zn.The dendrites were finer in size and highly branched in Mg-10Gd-6Zn.The corrosion results indicated that the increase in Zn content increased the corrosion rate in Mg-10Gd-xZn alloys.Micro-galvanic corrosion occurred near the grain boundary in both alloys initially as the grain boundary phase was stable and acted as a cathode,however,filiform corrosion dominated in the later stage,which was facilitated by the LPSO phase in the matrix.Severe micro-galvanic corrosion occurred in Mg-10Gd-6Zn due to the higher volume of second phase.The stability of the second phase at the grain boundary was altered and dissolved after the long immersion times.Probably the NaCl solution chemically reacted with the grain boundary phase and de-stabilized it during the long immersion times,and was removed by the chromic acid used for the corrosion product removal.
文摘A hallmark of all forms of neurodegenerative diseases is impairment of neuronal functions,and in many cases neuronal cell death.Although the etiology of neurodegenerative diseases may be distinct,different diseases display a similar pathogenesis,for example abnormal immunity within the central nervous system(CNS),activation of macrophage/microglia and the involvement of proinflammatory cytokines.Recent studies show that neurons in a neurodegenerative state undergo a highly regulated programmed cell death,also called apoptosis.TNF-related apoptosis-inducing ligand(TRAIL),a member of the TNF family,has been shown to be involved in apoptosis during many diseases.As one member of a death ligand family,TRAIL was originally thought to target only tumor cells and was not present in CNS.However,recent data showed that TRAIL was unregulated in HIV-1-infected and immune-activated macrophages,a major disease inducing cell during HIV-1-assoeiated dementia(HAD).TRAIL is also induced on neuron by β-amyloid protein,an important pathogen for Alzheimer's disease.In this review,we summarize the possible common aspects that TRAIL involved those neurodegenerative diseases,TRAIL induced apoptosis signaling in the CNS cells,and specific role of TRAIL in individual diseases.Cellular & Molecular Immunology.2005;2(2):113-122.
基金supported by the National Natural Science Foundation of China(Nos.22078118,21972048,22274059)the Guangdong Laboratory of Lingnan Modern Agriculture Project(Nos.NZ2021029,NT2021010)+1 种基金the Guangzhou Science and Technology Planning Project(No.202201010728)the Guangdong Provincial Key Laboratory of Distributed Energy Systems(No.2020B1212060075).
文摘The insensitivity of semiconductors to visible and infrared light is a key constraint on the utilization of light energy in photocatalytic reactions.Constructing photocatalysts with full-spectrum absorption through surface engineering is an effective approach to fully harnessing light energy in semiconductor materials.Herein,a novel stable Ti_(3)C_(2)T_(x)MXene/CdS heterojunction catalyst is obtained by in-situ epitaxial growth of two-dimensional(2D)CdS nanosheets on 2D MXene interface via a solvothermal method.The exceptional light absorption properties of MXene confer outstanding full-spectrum driven photocat-alytic hydrogen evolution capability upon the heterogeneous catalyst.The unique 2D/2D structure effectively mitigated the recombination of photogenerated carriers,enhancing the photocatalytic performance of the catalyst.Moreover,the composite catalyst exhibits a significantly higher surface temperature of 80.4℃under visible light irradiation at an intensity of 0.1 W/cm^(2),which is 1.84 times higher than that of CdS.Under irradiation of visible and near infrared light,the composite catalyst with photothermal ef-fect demonstrates a remarkable hydrogen evolution rate of 65.4 mmol g^(-1)h^(-1),which is 7.2 times higher than that of CdS catalyst.This study introduces a novel approach for constructing full-spectrum absorption catalysts and expands the application of the photothermal effect in photocatalytic hydrogen evolution research.
基金supported by NNSFC grants 42322408,42188101 and 42074202the Strategic Pioneer Program on Space Science,CAS Grant nos.XDA15350201+2 种基金in part by the Research Fund from the Chinese Academy of Sciencesthe Specialized Research Fund for State Key Laboratories of Chinasupported by the Young Elite Scientists Sponsorship Program(CAST-Y202045)。
文摘Following our earlier work on tomographic reconstruction of the magnetosheath soft X-ray emissions with superposed epoch analysis of many images recorded from a single spacecraft we now explore the instantaneous reconstruction of the magnetosheath and magnetopause using a few images recorded simultaneously from a few spacecraft.This work is motivated by the prospect of possibly having two or three soft X-ray imagers in space in the coming years,and that many phenomena which occur at the magnetopause boundary,such as reconnection events and pressure pulse responses,do not lend themselves as well to superposed epoch analysis.If the reconstruction is successful-which we demonstrate in this paper that it can be-this collection of imagers can be used to reconstruct the magnetosheath and magnetopause from a single image from each spacecraft,allowing for high time resolution reconstructions.In this paper we explore the reconstruction using,two,three,and four spacecraft.We show that the location of the subsolar point of the magnetopause can be determined with just two satellites,and that volume emissions of soft X-rays,and the shape of the boundary,can be reconstructed using three or more satellites.
基金National Institutes of Health(NIH)AG059217&AG061875 for TYHNIH AG062257,AG057509,AG054111,and AG020670 for HZNIH AG057981,BrightFocus Foundation A2016346F,Alzheimer Association AARG-17-500335,&Florida Department of Health 8AZ07 for CL.
文摘Background:Alzheimer’s disease(AD)is a fatal disease that threatens the quality of life of an aging population at a global scale.Various hypotheses on the etiology of AD have been developed over the years to guide efforts in search of therapeutic strategies.Main body:In this review,we focus on four AD hypotheses currently relevant to AD onset:the prevailing amyloid cascade hypothesis,the well-recognized tau hypothesis,the increasingly popular pathogen(viral infection)hypothesis,and the infection-related antimicrobial protection hypothesis.In briefly reviewing the main evidence supporting each hypothesis and discussing the questions that need to be addressed,we hope to gain a better understanding of the complicated multi-layered interactions in potential causal and/or risk factors in AD pathogenesis.As a defining feature of AD,the existence of amyloid deposits is likely fundamental to AD onset but is insufficient to wholly reproduce many complexities of the disorder.A similar belief is currently also applied to hyperphosphorylated tau aggregates within neurons,where tau has been postulated to drive neurodegeneration in the presence of pre-existing Aβplaques in the brain.Although infection of the central nerve system by pathogens such as viruses may increase AD risk,it is yet to be determined whether this phenomenon is applicable to all cases of sporadic AD and whether it is a primary trigger for AD onset.Lastly,the antimicrobial protection hypothesis provides insight into a potential physiological role for Aβpeptides,but how Aβ/microbial interactions affect AD pathogenesis during aging awaits further validation.Nevertheless,this hypothesis cautions potential adverse effects in Aβ-targeting therapies by hindering potential roles for Aβin anti-viral protection.Conclusion:AD is a multi-factor complex disorder,which likely requires a combinatorial therapeutic approach to successfully slow or reduce symptomatic memory decline.A better understanding of how various causal and/or risk factors affecting disease onse
文摘A single phase brushless spindle motor with innovative design has been developed for application in a DVD drive. The methods used to reduce the cogging torque and to improve the dynamic performance of this new design motor are proposed in this paper. The single phase brushless spindle motor is usually applied for cooling fan, pump and blower before the performance is improved by the reengineering process. The stator configuration and the drive circuit have been remodeled in order to meet the requirements of the spindle motor used in the DVD applications.
文摘Arteriovenous fistulas(AVFs)are a vital form of AV access for patients requiring hemodialysis,but they link to overall morbidity and mortality when they fail to mature.The most common cause of AVF non-maturation is neointimal hyperplasia(NIH).To minimize the deleterious effects of NIH,a perivascular wrap composed of polycaprolactone(PCL),rosuvastatin(ROSU),and gold nanoparticles(AUNPs)was constructed.This study assessed the impact of ROSU-eluting,radiopaque resorbable perivascular wraps on pathologic NIH in a chronic kidney disease(CKD)rodent model of AVF.Electrospun PCL wraps containing AuNPs and/or ROSU were monitored for in vitro tensile strength,AuNP release,ROSU elution,and effect on cellular viability.The wraps were then implanted around an AVF in a CKD rodent model for in vivo ultrasound(US)and micro-computed tomography(mCT)imaging.AVF specimens were collected for histological analyses.Cell viability was preserved in the presence of both AuNP-and ROSU-containing wraps.In vitro release of ROSU and AuNPs correlated with in vivo findings of decreasing radiopacity on mCT over time.AuNP-loaded wraps had higher radiopacity(1270.0-1412.0 HU at week 2)compared with other wraps(103.5-456.0 HU),which decreased over time.The addition of ROSU decreased US and histologic measurements of NIH.The reduced NIH seen with ROSU-loaded perivascular wraps suggests a synergistic effect between mechanical support and anti-hyperplasia medication.Furthermore,AuNP loading increased wrap radiopacity.Together,our results show that AuNP-and ROSU-loaded PCL wraps induce AVF maturation and suppress NIH while facilitating optimal implanted device visualization.
文摘Powder metallurgy is an efficient approach to fabricate varieties of high performance structure materials, function materials and special materials working under limited conditions. Research and development of new efficient technology to form high-density, high-performance and net shape parts is a key to widen application and development of powder materials. Recently, the low-voltage electromagnetic compaction (EMC) has been used by present authors to compacted copper, tin, aluminum powders and the products with 99% relative density have been acquired. In this work, the research has been extended to investigation on the density uniformity of pressed parts. The analysis results show that the density of the part compacted by low-voltage EMC decreases gradually in press direction as static compaction. But it is higher and more homogeneous. The density of the top part increases gradually from the center to the outer, which is just reversal of the bottom part. In some extent, the higher the discharging voltage is, the higher the density is and the more homogeneous the distribution is. In addition, repetitive compaction can improve the density of powder parts and the distribution uniformity.
基金This work was financially supported by the National NSFC BaoSteel Conjunct Foun dation(No.50174031).
文摘A mathematical model coupling the momentum, energy and species conservation equa-tions was proposed to calculate the macro--segregation of Fe--C alloy ingot during solid-ification. The corresponding simulation software which concurrently solves the macro-scopic mass, momentum, energy and species conservation equations has been developedby applying the SIMPLE algorithm.The thermo--solutal convection in a NH_4 Cl--H_2O ingot is verified and the result showsgood agreement with that reported. Then macro--segregation in a steel ingot is simu-lated by using the developed program. The steel ingot is in a rectangular mold with ariser. The fluid flow is mainly induced by the temperature field and the solid fraction.The macro--segregation pattern is mainly affected by the thermo--induced convectionin the mushy zone. The negative segregation forms along the walls of the casting.The positive segregation forms at the top center of the casting into the riser. Thespecies concentration reaches the peak in the center of the ingot where solidificationends lastly.
基金supported by the National Key R&D Program of China(2021YFA0718500)National Natural Science Foundation of China(NSFC,Grant Nos.U1838201,U1838202,11733009,11673023,U1838111,U1838108,U1838105,U1938102,U2038104,U1838110,U1838113,U1838115 and U2031205)。
文摘We report spectral and timing analysis of the black hole transient MAXI J1631–479 during the hard intermediate state of its 2019 outburst from the Insight-Hard X-ray Modulation Telescope(Insight-HXMT)observations.We find that the energy dependence of the type-C quasi-periodic oscillation(QPO)frequency evolves with time:during the initial rise of a small flare(~MJD 58526.0-58527.1),the QPO frequency increases with increasing energy from~1 to~100 ke V,and then the frequency remains constant after MJD 58527.1.We discover a possible new phenomenon of Fe line’s QPO frequency jump that has never been observed for other black hole transients:during the small flare,the QPO frequency around the Fe line energy is higher than any other energy band,with the frequency difference Δf=0.25±0.08 Hz between 5.5–7.5 ke V and other energy bands.The spectral analysis shows that the evolution of QPOs is related to the equivalent width of the narrow Fe line,and its equivalent width increases during this small flare.We propose that the QPO frequency difference results from the differential precession of a vertically extended jet,and the higher QPO frequency of Fe line could be caused by the layered jet when the jet scale increases.At the same time,the evolution of QPOs is related to the accretion rate,while the energy dependence of QPOs supports the existence of deceleration in the vertically distributed jet.
基金This work was supported by the Natural Science Foundation of Guangdong Province(2021A1515010630,2021A1515012102)GDAS Special Project of Science and Technology Development(2021GDASYL-20210103053)China Agriculture Research System(CARS-44-SYZ11).
文摘Brain transcriptional regulatory network for behavior demonstrates that brain gene expression in the honey bee can be accurately predicted from the expression transcription factors(TFs),but roles for specific TFs are less understood.Mushroom bodies(MBs)are important for learning,memory and sensory integration in the honey bee brain.A TFs,Mblk-1,expressed preferentially in the large-type Kenyon cells of the honeybee MBs is predicted to be involved in brain function by regulating transcription of its target genes in honey bee.However,its function and the mechanism of regulation in behavior of honey bee is still obscure.Here we show that Mblk-1 had significantly higher expression in the brains of forager bees relative to nurse bees.Mblk-1 was significantly inhibited in bees fed small interfering RNA.In addition,inhibition of Mblk-1 decreased sucrose responsiveness in foragers.Finally,we determined that Mblk-1 regulated the messenger RNA of AmGRl.These findings suggest that Mblk-1 may target AmGRl to regulate the sucrose responsiveness of foragers.
文摘The current studies on power plant technologies suggest that Integrated Gasification Combined Cycle(IGCC)systems are an effective and economic CO_(2) capture technology pathway.In addition,the system in conventional configuration has the advantage of being more“CO_(2) capture ready”than other technologies.Pulverized coal boilers(PC)have,however,proven high technical performance attributes and are economically often most practical technologies.To highlight the pros and cons of both technologies in connection with an integrated CO_(2) capture,a comparative analysis of ultrasupercritical PC and IGCC is carried out in this paper.The technical design,the mass and energy balance and the system optimizations are implemented by using the ECLIPSE chemical plant simulation software package.Built upon these technologies,the CO_(2) capture facilities are incorporated within the system.The most appropriate CO_(2) capture systems for the PC system selected for this work are the oxy-fuel system and the postcombustion scheme using Monoethanolamine solvent scrubber column(MEA).The IGCC systems are designed in two configurations:Water gas shift reactor and Selexol-based separation.Both options generate CO_(2)-rich and hydrogen rich-gas streams.Following the comparative analysis of the technical performance attributes of the above cycles,the economic assessment is carried out using the economic toolbox of ECLIPSE is seamlessly connected to the results of the mass and energy balance as well as the utility usages.The total cost assessment is implemented according to the stepcount exponential costing method using the dominant factors and/or a combination of parameters.Subsequently,based on a set of assumptions,the net present value estimation is implemented to calculate the breakeven electricity selling prices and the CO_(2) avoidance cost.
基金ONR Composites for Marine Structures Program(grant N00014-01-1-0205,Program Manager Dr.Y.D.S.Rajapakse)the National Basic Research Program of China(973 Program,2007CB936803)+1 种基金the NSFCMinistry of Education of China
文摘The nonlinear atomistic interactions usually involve softening behavior. Instability resulting directly from this softening are called the material instability, while those unrelated to this softening are called the structural instability. We use the finite-deformation shell theory based on the interatomic potential to show that the tension instability of single-wall carbon nanotubes is the material instability, while the compression and torsion instabilities are structural instability.
文摘The Low-lying excited states of HeH have been calculated by arrangement channel quantum mechanics(ACQM),The calculated potential curves,equilibrium geometry,Rc.dissociation energy Dc.harmonic vibration frequency ω0 and quadratic force coustant F2 are comparable with Ci calculations.
