Background:The egg production performance of chickens is affected by many factors,including genetics,nutrition and environmental conditions.These factors all play a role in egg production by affecting the development ...Background:The egg production performance of chickens is affected by many factors,including genetics,nutrition and environmental conditions.These factors all play a role in egg production by affecting the development of follicles.MicroRNAs(miRNAs)are important non-coding RNAs that regulate biological processes by targeting genes or other non-coding RNAs after transcription.In the animal reproduction process,miRNA is known to affect the development and atresia of follicles by regulating apoptosis and autophagy of granulosa cells(GCs).Results:In this study,we identified potential miRNAs in the atretic follicles of broody chickens and unatretic follicles of healthy chickens.We identified gga-miR-30a-5p in 50 differentially expressed miRNAs and found that gga-miR-30a-5p played a regulatory role in the development of chicken follicles.The function of miR-30a-5p was explored through the transfection test of miR-30a-5p inhibitor and miR-30a-5p mimics.In the study,we used qPCR,western blot and flow cytometry to detect granulosa cell apoptosis,autophagy and steroid hormone synthesis.Confocal microscopy and transmission electron microscopy are used for the observation of autophagolysosomes.The levels of estradiol(E2),progesterone(P4),malondialdehyde(MDA)and superoxide dismutase(SOD)were detected by ELISA.The results showed that miR-30a-5p showed a negative effect on autophagy and apoptosis of granulosa cells,and also contributed in steroid hormones and reactive oxygen species(ROS)production.In addition,the results obtained from the biosynthesis and dual luciferase experiments showed that Beclin1 was the target gene of miR-30a-5p.The rescue experiment conducted further confirmed that Beclin1 belongs to the miR-30a-5p regulatory pathway.Conclusions:In summary,after deep miRNA sequencing on healthy and atretic follicles,the results indicated that miR-30a-5p inhibits granulosa cell death by inhibiting Beclin1.展开更多
Carotenoids are essential components in tea quality, contributing to leaf color and aroma. However, little information about carotenoids in different tea cultivars and their biosynthesis regulation mechanism during le...Carotenoids are essential components in tea quality, contributing to leaf color and aroma. However, little information about carotenoids in different tea cultivars and their biosynthesis regulation mechanism during leaf development is known. Here we analyzed carotenoids by HPLC in the buds and leaves of 113 tea cultivars harvested on the same day. By profile clustering, carotenoids were divided into five groups. Same group cultivars displayed divergence in the total content of carotenoids but a similar molar ratio. To figure out the molecular mechanisms of this phenomenon, we further characterized all functional lycopene cyclases, which are the branch point of the carotenoid biosynthesis pathway. Two β-lycopene cyclases(CsLCYB1 and CsLCYB2) and one ε-lycopene cyclase(CsLCYE1) were cloned. Subcellular localization analysis showed that all cloned CsLCYs were localized in plastids. Enzyme activity assays in E. coli indicated both CsLCYBs catalyzed lycopene into β-carotene, and CsLCYE1 produced δ-carotene and ε-carotene. We found CsLCYB1 and CsLCYE1 predominantly expressed in leaf, while CsLCYB2was mainly expressed during flowering stages. Suppression by antisense oligonucleotides reduced CsLCYB1 and CsLCYE1 transcripts and led to reduction of both β,β-branch and β,ε-branch carotenoids in leaf. The expression levels of CsLCYB1 showed a significant positive correlation withβ,β-branch carotenoids in leaf. Our study provides carotenoid profiles of different tea cultivars, which can assist tea producers in selecting cultivars of interest. Meanwhile, we proposed the molecular mechanism of carotenoids reflecting the tenderness of tea plant leaf from a metabolic flux perspective, and suggested lycopene cyclase that could be applied to the breeding of tea varieties with different branch carotenoids.展开更多
The distribution of the thermal effects of the ion thruster plume are essential for estimating the influence of the thruster plume, improving the layout of the spacecraft, and for the thermal shielding of critical sen...The distribution of the thermal effects of the ion thruster plume are essential for estimating the influence of the thruster plume, improving the layout of the spacecraft, and for the thermal shielding of critical sensitive components. In order to obtain the heat flow distribution in the plume of the LIPS-200 xenon ion thruster, an experimental study of the thermal effects of the plume has been conducted in this work,with a total heat flow sensor and a radiant heat flow sensor over an axial distance of 0.5–0.9 m and a thruster angle of 0°–60°. Combined with a Faraday probe and a retarding potential analyzer, the thermal accommodation coefficient of the sensor surface in the plume is available. The results of the experiment show that the xenon ion thruster plume heat flow is mainly concentrated within a range of15°. The total and radial heat flow of the plume downstream of the thruster gradually decreases along the axial and radial directions, with the corresponding values of 11.78 k W m^(-2) and 0.3 k W m^(-2) for the axial 0.5 m position, respectively. At the same position, the radiation heat flow accounts for a very small part of the total heat flow, approximately 3%–5%. The thermal accommodation factor is0.72–0.99 over the measured region. Furthermore, the PIC and DSMC methods based on the Maxwell thermal accommodation coefficient model(EX-PWS) show a maximum error of 28.6% between simulation and experiment for LIPS-200 ion thruster plume heat flow, which, on the one hand, provides an experimental basis for studying the interaction between the ion thruster and the spacecraft, and on the other hand provides optimization of the ion thruster plume simulation model.展开更多
This study investigates the electromagnetohydrodynamic(EMHD)flow of fractional viscoelastic fluids through a microchannel under the Navier slip boundary condition.The flow is driven by the pressure gradient and electr...This study investigates the electromagnetohydrodynamic(EMHD)flow of fractional viscoelastic fluids through a microchannel under the Navier slip boundary condition.The flow is driven by the pressure gradient and electromagnetic force where the electric field is applied horizontally,and the magnetic field is vertically(upward or downward).When the electric field direction is consistent with the pressure gradient direction,the changes of the steady flow rate and velocity with the Hartmann number Ha are irrelevant to the direction of the magnetic field(upward or downward).The steady flow rate decreases monotonically to zero with the increase in Ha.In contrast,when the direction of the electric field differs from the pressure gradient direction,the flow behavior depends on the direction of the magnetic field,i.e.,symmetry breaking occurs.Specifically,when the magnetic field is vertically upward,the steady flow rate increases first and then decreases with Ha.When the magnetic field is reversed,the steady flow rate first reduces to zero as Ha increases from zero.As Ha continues to increase,the steady flow rate(velocity)increases in the opposite direction and then decreases,and finally drops to zero for larger Ha.The increase in the fractional calculus parameterαor Deborah number De makes it take longer for the flow rate(velocity)to reach the steady state.In addition,the increase in the strength of the magnetic field or electric field,or in the pressure gradient tends to accelerate the slip velocity at the walls.On the other hand,the increase in the thickness of the electric double-layer tends to reduce it.展开更多
Transpiration through stomata in tree canopies plays an important role in terrestrial water cycles.However, the empirical relationship between leaf stomata anatomy and canopy stomatal conductance（Gs） is surprisingly...Transpiration through stomata in tree canopies plays an important role in terrestrial water cycles.However, the empirical relationship between leaf stomata anatomy and canopy stomatal conductance（Gs） is surprisingly rare, thereby the underlying biological mechanisms of terrestrial water flux are not well elucidated. To gain further insight into these mechanisms, we reanalyzed the dataset of Gspreviously reported by Gao et al.（2015） using a quantile regression model. The results indicated that the reference Gs(Gsref, Gs at 1 kPa) was negatively correlated with wood density at each quantile, which confirmed previous data; however, Gsrefwas significantly correlated with stomatal density at the 0.6 quantile, i.e., 450 stomata mm-2. This highlighted the potential of using stomatal density as a trait to predict canopy water flux. A conceptual model of co-determinants of xylem and stomatal morphology suggests that these traits and their coordination may play a critical role in determining tree growth,physiological homeostatic response to environmental variables, water use efficiency, and drought resistance.展开更多
Curved channels are ubiquitous in microfluidic systems.The pressure-driven electrokinetic flow and energy conversion in a curved microtube are investigated analytically by using a perturbation analysis method under th...Curved channels are ubiquitous in microfluidic systems.The pressure-driven electrokinetic flow and energy conversion in a curved microtube are investigated analytically by using a perturbation analysis method under the assumptions of the small curvature ratio and the Reynolds number.The results indicate that the curvature of the microtube leads to a skewed pattern in the distribution of the electrical double layer(EDL)potential.The EDL potential at the outer side of the bend is larger than that at the inner side of the bend.The curvature shows an inhibitory effect on the magnitude of the streaming potential field induced by the pressure-driven flow.Since the spanwise pressure gradient is dominant over the inertial force,the resulting axial velocity profile is skewed into the inner region of the curved channel.Furthermore,the flow rate in a curved microtube could be larger than that in a straight one with the same pressure gradient and shape of cross section.The asymptotic solutions of the axial velocity and flow rate in the absence of the electrokinetic effect are in agreement with the classical results for low Reynolds number flows.Remarkably,the curved geometry could be beneficial to improving the electrokinetic energy conversion(EKEC)efficiency.展开更多
Energy conversion in micro/nano-systems is a subject of current research,among which the electrokinetic energy conversion has attracted extensive attention.However,there exist two different definitions on the electrok...Energy conversion in micro/nano-systems is a subject of current research,among which the electrokinetic energy conversion has attracted extensive attention.However,there exist two different definitions on the electrokinetic energy conversion efficiency in literature.A few researchers defined the efficiency using the pure pressure-driven flow rate,while other groups defined the efficiency based on the flow rate with the inclusion of the effect of the streaming potential field.In this work,both definitions are investigated for different fluid types under the periodic electrokinetic flow condition.For Newtonian fluids,the two definitions give similar results.However,for viscoelastic fluids,these two definitions lead to significant difference.The efficiency defined by the pure pressure-driven flow rate even exceeds 100%in a certain range of the parameters.The result shows that in the case of viscoelastic flow,it is incorrect to define the energy conversion efficiency by pure pressure-driven flow rate.At the same time,the reason for this problem is clarified through comprehensive analysis.展开更多
Molybdenum oxide/sulfide materials are extensively evaluated as high-capacity anode candidates for lithium ion batteries.However,they suffer from rapid capacity decay and poor kinetics.Herein,we report on synergistic ...Molybdenum oxide/sulfide materials are extensively evaluated as high-capacity anode candidates for lithium ion batteries.However,they suffer from rapid capacity decay and poor kinetics.Herein,we report on synergistic effect from structurally integrated coaxial CNTs@MoS_(2)/MoO_(2) composite material on lithium storage,in which MoS_(2)/MoO_(2) nanosheets are conformally decorated on carbon nanotubes(CNTs).In-situ synchrotron X-ray diffraction measurement is performed to elucidate synergistic effect among three MoS_(2),MoO_(2) and CNTs components for lithium storage.Reaction mechanism exploration reveals that the MoO_(2) component undergoes reversible Li^(+)intercalation via forming a stable Li_(0.98) MoO_(2) phase over a voltage range of 3.0 to 0.01 V vs.Li^(+)/Li,without experiencing the conversion reaction into metallic Mo,which contributes to long-term stability during charge/discharge cycles.Meanwhile,lithium storage of MoS_(2) is through lithium and sulfur reversible reaction after the initial conversion reaction of lithiated MoS_(2) forming Li_(2)S and Mo.The CNTs component enhances electronic conductivity and structural stability by minimizing volume change and reaction strains in the CNTs@MoS_(2)/MoO_(2) composite anode.A desired 68.2%capacity retention upon 2000 cycles at 10 A/g has been demonstrated for the CNTs@MoS_(2)/MoO_(2) anode,revealing prominent reaction kinetics and structural stability for fast and stable lithium storage,superior to various Mo-based anode materials previously reported.The findings from this study,with the unique insight into the role of structural integrity in combining MoS_(2)/MoO_(2) materials with the CNTs substrate,offers a strategy for designing composite anode materials for superior lithium storage performance.展开更多
Texture analysis is a fundamental field in computer vision. However,it is also a particularly difficult problem for no universal mathematical model of real world textures. By extending a new application of the fractio...Texture analysis is a fundamental field in computer vision. However,it is also a particularly difficult problem for no universal mathematical model of real world textures. By extending a new application of the fractional Fourier transform( Fr FT) in the field of texture analysis,this paper proposes an Fr FT-based method for describing textures. Firstly,based on the Radon-Wigner transform,1-D directional Fr FT filters are designed to two types of texture features,i. e.,the coarseness and directionality. Then,the frequencies with maximum and median amplitudes of the Fr FT of the input signal are regarded as the output of the 1-D directional Fr FT filter. Finally,the mean and the standard deviation are used to compose of the feature vector. Compared to the WD-based method,three benefits can be achieved with the proposed Fr FT-based method,i. e.,less memory size,lower computational load,and less disturbed by the cross-terms. The proposed method has been tested on16 standard texture images. The experimental results show that the proposed method is superior to the popular Gabor filtering-based method.展开更多
The accurate knowledge of the thrust vector eccentricity and beam divergence characteristics of Hall thrusters are of significant engineering value for the beneficial integration and successful application of Hall thr...The accurate knowledge of the thrust vector eccentricity and beam divergence characteristics of Hall thrusters are of significant engineering value for the beneficial integration and successful application of Hall thrusters on spacecraft.For the characteristics of the plume bipolar diffusion due to the annular discharge channel of the Hall thruster,a Gaussian-fitted method for thrust vector deviation angle and beam divergence of Hall thrusters based on dual Faraday probe array planes was proposed in respect of the Hall thruster beam characteristics.The results show that the ratios of the deviation between the maximum and minimum values of the beam divergence angle and the thrust vector eccentricity angle using a Gaussian fit to the optimized Faraday probe dual plane to the mean value are 1.4%and 11.5%,respectively.The optimized thrust vector eccentricity angle obtained has been substantially improved,by approximately 20%.The beam divergence angle calculated using a Gaussian fitting to the optimized Faraday probe dual plane is approximately identical to the non-optimized one.The beam divergence and thrust vector eccentricity angles for different anode mass flow rates were obtained by averaging the beam divergence and thrust vector eccentricity angles calculated by the dual-plane,Gaussian-fitted ion current density method for different cross-sections.The study not only allows for an immediate and effective tool for determining the design of thrust vector adjustment mechanisms of spacecraft with different power Hall thrusters but also for characterizing the 3D spatial distribution of the Hall thruster plume.展开更多
The advent of the post-pandemic era,with its risks,uncertainties,and global characteristics,puts forward urgent requirements for the innovation of information literacy education in universities.Critical information li...The advent of the post-pandemic era,with its risks,uncertainties,and global characteristics,puts forward urgent requirements for the innovation of information literacy education in universities.Critical information literacy has become the top priority of information literacy education.It is urgent to explore diversified and effective critical information literacy education strategies for university students.This paper mainly expounds the educational strategies of critical information literacy,such as original material analysis,reflection,and critical reading.展开更多
Conventional frequency-sweep interferometry is unreliable for noncooperative or long-distance targets owing to scattering on the target surface.Hence,this paper proposes a laser frequency-swept carrier(LFSC)ranging me...Conventional frequency-sweep interferometry is unreliable for noncooperative or long-distance targets owing to scattering on the target surface.Hence,this paper proposes a laser frequency-swept carrier(LFSC)ranging method based on resonant cavity enhancement for long-distance noncooperative target measurements and weak-signal detection.Experimental verification revealed that for a target comprising an oxidized black aluminum plate at a distance of 16 m,the standard deviation of 10 measurements was less than 70μm,measurement accuracy exceeded 27μm,and system ranging resolution exceeded 0.13 mm when the target feedback light was very weak.This method is useful for measurements of noncooperative targets,eg.,large-scale component assembly,industrial measurement,and biomedical testing.展开更多
Objective Osteosarcoma is a prevalent primary malignant bone tumor in children and adolescents,accounting for approximately 5%of childhood malignancies.Because of its rarity and biological complexity,treatment breakth...Objective Osteosarcoma is a prevalent primary malignant bone tumor in children and adolescents,accounting for approximately 5%of childhood malignancies.Because of its rarity and biological complexity,treatment breakthroughs for osteosarcoma have been limited.To advance research in this field,we aimed to construct the first comprehensive osteosarcoma knowledge graph(OSKG)using the PubMed database.Methods A systematic search of PubMed(2003-2023)using the keyword"osteosarcoma"yielded 25,415 abstracts.Leveraging BioBERT,pretrained on biomedical corpora and fine-tuned with osteosarcoma-specific manual annotations,we identified 16 entity types and 17 biological relationships.The extracted elements were synthesized to create the OSKG,resulting in a deep learning-based knowledge base to explore osteosarcoma pathogenesis and molecular mechanisms.We then developed a specialized question-answering system(knowledge graph question answering(KGQA))powered by ChatGLM3.This system employs advanced natural language processing and incorporates the OSKG to ensure optimal response quality and accuracy.Results The pretrained BioBERT averaged>92%accuracy in entity and relationship training.Evaluation using 100 pairs of gold-standard quizzes showed that the final quiz system outperformed other large language models in accuracy and robustness.Conclusion The system is designed to provide accurate disease-related queries and answers,effectively facilitating knowledge acquisition and reasoning in medical research and clinical practice.This project offers a robust tool for osteosarcoma research and promotes the deep integration of knowledge graphs and artificial intelligence technologies in the medical field.展开更多
In this paper,we examine the tiny polarization rotation effect in total internal reflection due to the spin–orbit interaction of light.We find that the tiny polarization rotation rate will induce a geometric phase gr...In this paper,we examine the tiny polarization rotation effect in total internal reflection due to the spin–orbit interaction of light.We find that the tiny polarization rotation rate will induce a geometric phase gradient,which can be regarded as the physical origin of photonic spin Hall effect.We demonstrate that the spin-dependent splitting in position space is related to the polarization rotation in momentum space,while the spin-dependent splitting in momentum space is attributed to the polarization rotation in position space.Furthermore,we introduce a quantum weak measurement to determine the tiny polarization rotation rate.The rotation rate in momentum space is obtained with 118 nm,which manifests itself as a spatial shift,and the rotation rate in position space is achieved with 38 μrad∕λ,which manifests itself as an angular shift.The investigation of the polarization rotation characteristics will provide insights into the photonic spin Hall effect and will enable us to better understand the spin–orbit interaction of light.展开更多
基金financially supported by Sichuan Science and Technology Program(2021YFYZ0031,2021YFYZ0007)China Agriculture Research System of MOF and MARA(CARS-40).
文摘Background:The egg production performance of chickens is affected by many factors,including genetics,nutrition and environmental conditions.These factors all play a role in egg production by affecting the development of follicles.MicroRNAs(miRNAs)are important non-coding RNAs that regulate biological processes by targeting genes or other non-coding RNAs after transcription.In the animal reproduction process,miRNA is known to affect the development and atresia of follicles by regulating apoptosis and autophagy of granulosa cells(GCs).Results:In this study,we identified potential miRNAs in the atretic follicles of broody chickens and unatretic follicles of healthy chickens.We identified gga-miR-30a-5p in 50 differentially expressed miRNAs and found that gga-miR-30a-5p played a regulatory role in the development of chicken follicles.The function of miR-30a-5p was explored through the transfection test of miR-30a-5p inhibitor and miR-30a-5p mimics.In the study,we used qPCR,western blot and flow cytometry to detect granulosa cell apoptosis,autophagy and steroid hormone synthesis.Confocal microscopy and transmission electron microscopy are used for the observation of autophagolysosomes.The levels of estradiol(E2),progesterone(P4),malondialdehyde(MDA)and superoxide dismutase(SOD)were detected by ELISA.The results showed that miR-30a-5p showed a negative effect on autophagy and apoptosis of granulosa cells,and also contributed in steroid hormones and reactive oxygen species(ROS)production.In addition,the results obtained from the biosynthesis and dual luciferase experiments showed that Beclin1 was the target gene of miR-30a-5p.The rescue experiment conducted further confirmed that Beclin1 belongs to the miR-30a-5p regulatory pathway.Conclusions:In summary,after deep miRNA sequencing on healthy and atretic follicles,the results indicated that miR-30a-5p inhibits granulosa cell death by inhibiting Beclin1.
基金supported by grants from the National Natural Science Foundation of China (Grant No.32102433)。
文摘Carotenoids are essential components in tea quality, contributing to leaf color and aroma. However, little information about carotenoids in different tea cultivars and their biosynthesis regulation mechanism during leaf development is known. Here we analyzed carotenoids by HPLC in the buds and leaves of 113 tea cultivars harvested on the same day. By profile clustering, carotenoids were divided into five groups. Same group cultivars displayed divergence in the total content of carotenoids but a similar molar ratio. To figure out the molecular mechanisms of this phenomenon, we further characterized all functional lycopene cyclases, which are the branch point of the carotenoid biosynthesis pathway. Two β-lycopene cyclases(CsLCYB1 and CsLCYB2) and one ε-lycopene cyclase(CsLCYE1) were cloned. Subcellular localization analysis showed that all cloned CsLCYs were localized in plastids. Enzyme activity assays in E. coli indicated both CsLCYBs catalyzed lycopene into β-carotene, and CsLCYE1 produced δ-carotene and ε-carotene. We found CsLCYB1 and CsLCYE1 predominantly expressed in leaf, while CsLCYB2was mainly expressed during flowering stages. Suppression by antisense oligonucleotides reduced CsLCYB1 and CsLCYE1 transcripts and led to reduction of both β,β-branch and β,ε-branch carotenoids in leaf. The expression levels of CsLCYB1 showed a significant positive correlation withβ,β-branch carotenoids in leaf. Our study provides carotenoid profiles of different tea cultivars, which can assist tea producers in selecting cultivars of interest. Meanwhile, we proposed the molecular mechanism of carotenoids reflecting the tenderness of tea plant leaf from a metabolic flux perspective, and suggested lycopene cyclase that could be applied to the breeding of tea varieties with different branch carotenoids.
基金National Natural Science Foundation of China (No. 12005087)the Science and Technology Program of Gansu Province (Nos. 2006ZCTF0054, HTKJ2019KL510003, and 20JR10RA478)。
文摘The distribution of the thermal effects of the ion thruster plume are essential for estimating the influence of the thruster plume, improving the layout of the spacecraft, and for the thermal shielding of critical sensitive components. In order to obtain the heat flow distribution in the plume of the LIPS-200 xenon ion thruster, an experimental study of the thermal effects of the plume has been conducted in this work,with a total heat flow sensor and a radiant heat flow sensor over an axial distance of 0.5–0.9 m and a thruster angle of 0°–60°. Combined with a Faraday probe and a retarding potential analyzer, the thermal accommodation coefficient of the sensor surface in the plume is available. The results of the experiment show that the xenon ion thruster plume heat flow is mainly concentrated within a range of15°. The total and radial heat flow of the plume downstream of the thruster gradually decreases along the axial and radial directions, with the corresponding values of 11.78 k W m^(-2) and 0.3 k W m^(-2) for the axial 0.5 m position, respectively. At the same position, the radiation heat flow accounts for a very small part of the total heat flow, approximately 3%–5%. The thermal accommodation factor is0.72–0.99 over the measured region. Furthermore, the PIC and DSMC methods based on the Maxwell thermal accommodation coefficient model(EX-PWS) show a maximum error of 28.6% between simulation and experiment for LIPS-200 ion thruster plume heat flow, which, on the one hand, provides an experimental basis for studying the interaction between the ion thruster and the spacecraft, and on the other hand provides optimization of the ion thruster plume simulation model.
基金supported by the National Natural Science Foundation of China(No.11902165)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2019BS01004)。
文摘This study investigates the electromagnetohydrodynamic(EMHD)flow of fractional viscoelastic fluids through a microchannel under the Navier slip boundary condition.The flow is driven by the pressure gradient and electromagnetic force where the electric field is applied horizontally,and the magnetic field is vertically(upward or downward).When the electric field direction is consistent with the pressure gradient direction,the changes of the steady flow rate and velocity with the Hartmann number Ha are irrelevant to the direction of the magnetic field(upward or downward).The steady flow rate decreases monotonically to zero with the increase in Ha.In contrast,when the direction of the electric field differs from the pressure gradient direction,the flow behavior depends on the direction of the magnetic field,i.e.,symmetry breaking occurs.Specifically,when the magnetic field is vertically upward,the steady flow rate increases first and then decreases with Ha.When the magnetic field is reversed,the steady flow rate first reduces to zero as Ha increases from zero.As Ha continues to increase,the steady flow rate(velocity)increases in the opposite direction and then decreases,and finally drops to zero for larger Ha.The increase in the fractional calculus parameterαor Deborah number De makes it take longer for the flow rate(velocity)to reach the steady state.In addition,the increase in the strength of the magnetic field or electric field,or in the pressure gradient tends to accelerate the slip velocity at the walls.On the other hand,the increase in the thickness of the electric double-layer tends to reduce it.
文摘Transpiration through stomata in tree canopies plays an important role in terrestrial water cycles.However, the empirical relationship between leaf stomata anatomy and canopy stomatal conductance（Gs） is surprisingly rare, thereby the underlying biological mechanisms of terrestrial water flux are not well elucidated. To gain further insight into these mechanisms, we reanalyzed the dataset of Gspreviously reported by Gao et al.（2015） using a quantile regression model. The results indicated that the reference Gs(Gsref, Gs at 1 kPa) was negatively correlated with wood density at each quantile, which confirmed previous data; however, Gsrefwas significantly correlated with stomatal density at the 0.6 quantile, i.e., 450 stomata mm-2. This highlighted the potential of using stomatal density as a trait to predict canopy water flux. A conceptual model of co-determinants of xylem and stomatal morphology suggests that these traits and their coordination may play a critical role in determining tree growth,physiological homeostatic response to environmental variables, water use efficiency, and drought resistance.
基金Project supported by the National Natural Science Foundation of China(Nos.11902165 and 11772162)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2019BS01004)the Inner Mongolia Grassland Talent of China(No.12000-12102408)。
文摘Curved channels are ubiquitous in microfluidic systems.The pressure-driven electrokinetic flow and energy conversion in a curved microtube are investigated analytically by using a perturbation analysis method under the assumptions of the small curvature ratio and the Reynolds number.The results indicate that the curvature of the microtube leads to a skewed pattern in the distribution of the electrical double layer(EDL)potential.The EDL potential at the outer side of the bend is larger than that at the inner side of the bend.The curvature shows an inhibitory effect on the magnitude of the streaming potential field induced by the pressure-driven flow.Since the spanwise pressure gradient is dominant over the inertial force,the resulting axial velocity profile is skewed into the inner region of the curved channel.Furthermore,the flow rate in a curved microtube could be larger than that in a straight one with the same pressure gradient and shape of cross section.The asymptotic solutions of the axial velocity and flow rate in the absence of the electrokinetic effect are in agreement with the classical results for low Reynolds number flows.Remarkably,the curved geometry could be beneficial to improving the electrokinetic energy conversion(EKEC)efficiency.
基金Project supported by the National Natural Science Foundation of China(Nos.11902165,11772162,and 11862018)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(Nos.2019BS01004 and 2021MS01007)the Inner Mongolia Grassland Talent(No.12000-12102013)。
文摘Energy conversion in micro/nano-systems is a subject of current research,among which the electrokinetic energy conversion has attracted extensive attention.However,there exist two different definitions on the electrokinetic energy conversion efficiency in literature.A few researchers defined the efficiency using the pure pressure-driven flow rate,while other groups defined the efficiency based on the flow rate with the inclusion of the effect of the streaming potential field.In this work,both definitions are investigated for different fluid types under the periodic electrokinetic flow condition.For Newtonian fluids,the two definitions give similar results.However,for viscoelastic fluids,these two definitions lead to significant difference.The efficiency defined by the pure pressure-driven flow rate even exceeds 100%in a certain range of the parameters.The result shows that in the case of viscoelastic flow,it is incorrect to define the energy conversion efficiency by pure pressure-driven flow rate.At the same time,the reason for this problem is clarified through comprehensive analysis.
基金supported by the National Natural Science Foundation of China[grant numbers 21703147 and U1401248],Chinathe Natural Science Foundations for the Young Scientist of Jiangsu Province[grant number BK20170338],Chinathe Open Fund of Jiangsu Key Laboratory of Materials and Technology for Energy Conversion[grant number MTEC-2017M01],China。
文摘Molybdenum oxide/sulfide materials are extensively evaluated as high-capacity anode candidates for lithium ion batteries.However,they suffer from rapid capacity decay and poor kinetics.Herein,we report on synergistic effect from structurally integrated coaxial CNTs@MoS_(2)/MoO_(2) composite material on lithium storage,in which MoS_(2)/MoO_(2) nanosheets are conformally decorated on carbon nanotubes(CNTs).In-situ synchrotron X-ray diffraction measurement is performed to elucidate synergistic effect among three MoS_(2),MoO_(2) and CNTs components for lithium storage.Reaction mechanism exploration reveals that the MoO_(2) component undergoes reversible Li^(+)intercalation via forming a stable Li_(0.98) MoO_(2) phase over a voltage range of 3.0 to 0.01 V vs.Li^(+)/Li,without experiencing the conversion reaction into metallic Mo,which contributes to long-term stability during charge/discharge cycles.Meanwhile,lithium storage of MoS_(2) is through lithium and sulfur reversible reaction after the initial conversion reaction of lithiated MoS_(2) forming Li_(2)S and Mo.The CNTs component enhances electronic conductivity and structural stability by minimizing volume change and reaction strains in the CNTs@MoS_(2)/MoO_(2) composite anode.A desired 68.2%capacity retention upon 2000 cycles at 10 A/g has been demonstrated for the CNTs@MoS_(2)/MoO_(2) anode,revealing prominent reaction kinetics and structural stability for fast and stable lithium storage,superior to various Mo-based anode materials previously reported.The findings from this study,with the unique insight into the role of structural integrity in combining MoS_(2)/MoO_(2) materials with the CNTs substrate,offers a strategy for designing composite anode materials for superior lithium storage performance.
基金Sponsored by the National Natural Science Foundation of China(Grant No.61003128)
文摘Texture analysis is a fundamental field in computer vision. However,it is also a particularly difficult problem for no universal mathematical model of real world textures. By extending a new application of the fractional Fourier transform( Fr FT) in the field of texture analysis,this paper proposes an Fr FT-based method for describing textures. Firstly,based on the Radon-Wigner transform,1-D directional Fr FT filters are designed to two types of texture features,i. e.,the coarseness and directionality. Then,the frequencies with maximum and median amplitudes of the Fr FT of the input signal are regarded as the output of the 1-D directional Fr FT filter. Finally,the mean and the standard deviation are used to compose of the feature vector. Compared to the WD-based method,three benefits can be achieved with the proposed Fr FT-based method,i. e.,less memory size,lower computational load,and less disturbed by the cross-terms. The proposed method has been tested on16 standard texture images. The experimental results show that the proposed method is superior to the popular Gabor filtering-based method.
基金the Key Laboratory Funds for Science and Technology on Vacuum Technology and Physics Laboratory(No.HTKJ2022KL510002)the Military Test Instruments Program(No.2006ZCTF0054)。
文摘The accurate knowledge of the thrust vector eccentricity and beam divergence characteristics of Hall thrusters are of significant engineering value for the beneficial integration and successful application of Hall thrusters on spacecraft.For the characteristics of the plume bipolar diffusion due to the annular discharge channel of the Hall thruster,a Gaussian-fitted method for thrust vector deviation angle and beam divergence of Hall thrusters based on dual Faraday probe array planes was proposed in respect of the Hall thruster beam characteristics.The results show that the ratios of the deviation between the maximum and minimum values of the beam divergence angle and the thrust vector eccentricity angle using a Gaussian fit to the optimized Faraday probe dual plane to the mean value are 1.4%and 11.5%,respectively.The optimized thrust vector eccentricity angle obtained has been substantially improved,by approximately 20%.The beam divergence angle calculated using a Gaussian fitting to the optimized Faraday probe dual plane is approximately identical to the non-optimized one.The beam divergence and thrust vector eccentricity angles for different anode mass flow rates were obtained by averaging the beam divergence and thrust vector eccentricity angles calculated by the dual-plane,Gaussian-fitted ion current density method for different cross-sections.The study not only allows for an immediate and effective tool for determining the design of thrust vector adjustment mechanisms of spacecraft with different power Hall thrusters but also for characterizing the 3D spatial distribution of the Hall thruster plume.
基金The 2020 Ideological and Political Education Research Project of Shandong University of Science and Technology“Research on Critical Information Literacy Education Strategies for Undergraduates in the Post Epidemic Era”(Project Number:SZJYY-20138)。
文摘The advent of the post-pandemic era,with its risks,uncertainties,and global characteristics,puts forward urgent requirements for the innovation of information literacy education in universities.Critical information literacy has become the top priority of information literacy education.It is urgent to explore diversified and effective critical information literacy education strategies for university students.This paper mainly expounds the educational strategies of critical information literacy,such as original material analysis,reflection,and critical reading.
基金National Natural Science Foundation of China(52475532, 51875447)
文摘Conventional frequency-sweep interferometry is unreliable for noncooperative or long-distance targets owing to scattering on the target surface.Hence,this paper proposes a laser frequency-swept carrier(LFSC)ranging method based on resonant cavity enhancement for long-distance noncooperative target measurements and weak-signal detection.Experimental verification revealed that for a target comprising an oxidized black aluminum plate at a distance of 16 m,the standard deviation of 10 measurements was less than 70μm,measurement accuracy exceeded 27μm,and system ranging resolution exceeded 0.13 mm when the target feedback light was very weak.This method is useful for measurements of noncooperative targets,eg.,large-scale component assembly,industrial measurement,and biomedical testing.
基金supported by grants fromthe National Key Research and Development Program of China(Program No.2021YFC2400600/2021YFC2400605)the Post-graduate Science Popularization Capability Promotion Program for 2022 sponsored by China Association for Science and Technology(Grant No.KXYJS2022098).
文摘Objective Osteosarcoma is a prevalent primary malignant bone tumor in children and adolescents,accounting for approximately 5%of childhood malignancies.Because of its rarity and biological complexity,treatment breakthroughs for osteosarcoma have been limited.To advance research in this field,we aimed to construct the first comprehensive osteosarcoma knowledge graph(OSKG)using the PubMed database.Methods A systematic search of PubMed(2003-2023)using the keyword"osteosarcoma"yielded 25,415 abstracts.Leveraging BioBERT,pretrained on biomedical corpora and fine-tuned with osteosarcoma-specific manual annotations,we identified 16 entity types and 17 biological relationships.The extracted elements were synthesized to create the OSKG,resulting in a deep learning-based knowledge base to explore osteosarcoma pathogenesis and molecular mechanisms.We then developed a specialized question-answering system(knowledge graph question answering(KGQA))powered by ChatGLM3.This system employs advanced natural language processing and incorporates the OSKG to ensure optimal response quality and accuracy.Results The pretrained BioBERT averaged>92%accuracy in entity and relationship training.Evaluation using 100 pairs of gold-standard quizzes showed that the final quiz system outperformed other large language models in accuracy and robustness.Conclusion The system is designed to provide accurate disease-related queries and answers,effectively facilitating knowledge acquisition and reasoning in medical research and clinical practice.This project offers a robust tool for osteosarcoma research and promotes the deep integration of knowledge graphs and artificial intelligence technologies in the medical field.
基金National Natural Science Foundation of China(NSFC)(11274106,11474089)
文摘In this paper,we examine the tiny polarization rotation effect in total internal reflection due to the spin–orbit interaction of light.We find that the tiny polarization rotation rate will induce a geometric phase gradient,which can be regarded as the physical origin of photonic spin Hall effect.We demonstrate that the spin-dependent splitting in position space is related to the polarization rotation in momentum space,while the spin-dependent splitting in momentum space is attributed to the polarization rotation in position space.Furthermore,we introduce a quantum weak measurement to determine the tiny polarization rotation rate.The rotation rate in momentum space is obtained with 118 nm,which manifests itself as a spatial shift,and the rotation rate in position space is achieved with 38 μrad∕λ,which manifests itself as an angular shift.The investigation of the polarization rotation characteristics will provide insights into the photonic spin Hall effect and will enable us to better understand the spin–orbit interaction of light.
