Nonreciprocal isolators enable unidirectional light propagation without back-reflection.Typical terahertz isolators require magnetic fields to break the time-reversal symmetry.Herein,we propose a nonmagnetic isolator ...Nonreciprocal isolators enable unidirectional light propagation without back-reflection.Typical terahertz isolators require magnetic fields to break the time-reversal symmetry.Herein,we propose a nonmagnetic isolator in the terahertz range based on nonreciprocal graphene plasmons operated in a reflection configuration.The bias voltage generates a drift current in graphene,which breaks the time-reversal symmetry and induces nonreciprocal reflection.The isolator device exhibited a high isolation exceeding 20 d B with an insertion loss of less than 3 d B.Moreover,the bandwidth wit isolation exceeding 20 d B can be broadened five times to 1.7 THz by tuning the carrier density.The indexes,including the isolation,insertion loss and bandwidth of the isolator,show a strong dependence on the drift velocity and mobility of graphene,as well as the air-gap thickness.Our study shows great potential in the burgeoning terahertz technology,where nonmagnetic and electrically tunable isolators are still lacking.展开更多
A new stirring method,reciprocating stirring,is developed by incorporating a periodic axial reciprocating motion into conventional stirring.This study employs computational fluid dynamics methods,utilizing volume of f...A new stirring method,reciprocating stirring,is developed by incorporating a periodic axial reciprocating motion into conventional stirring.This study employs computational fluid dynamics methods,utilizing volume of fluid and user-defined functions to control and analyze the flow field characteristics in a reciprocating stirred tank.Compared to conventional stirring,reciprocating stirring increases the overall fluid velocity by approximately 7.9%,turbulent kinetic energy(TKE)by 35.9%to 45.6%,and the turbulent dissipation rate by 10.6%to 15.7%.The primary reason is the dynamic integration of multiple flow regions,which enhances fluid interface interactions.Additionally,the study investigates the dynamic evolution of the vortex structure,uncovering the correlation between the impeller's start-stop behavior and the vortex area.The optimal impeller plate designs,forward sine-4/12D and reverse sine-5/12D,were determined based on the effective area of TKE.Reciprocating stirring,in comparison to conventional stirring,enhances secondary flow intensity by 67.3%to 93.7%and shortens mixing time by 56.6%to 173.0%.展开更多
The U.S.imposition of high tariffs on Chinese goods has triggered short-term strains on China’s exports.At the same time,it has also accelerated its strategic pivot toward technological self-reliance,regional integra...The U.S.imposition of high tariffs on Chinese goods has triggered short-term strains on China’s exports.At the same time,it has also accelerated its strategic pivot toward technological self-reliance,regional integration,and domestic demand expansion.展开更多
The vectorial evolution of light polarization can reveal the microstructure and anisotropy of a medium beyond what can be obtained from measuring light intensity alone.However,polarization imaging in reflection geomet...The vectorial evolution of light polarization can reveal the microstructure and anisotropy of a medium beyond what can be obtained from measuring light intensity alone.However,polarization imaging in reflection geometry,which is ubiquitous and often preferred in diverse applications,has often suffered from poor and even incorrect characterization of anisotropic media.We present reciprocal polarization imaging of complex media in reflection geometry with the reciprocal polar decomposition of backscattering Mueller matrices enforcing reciprocity.We demonstrate that reciprocal polarization imaging of complex chiral and anisotropic media ac-curately quantifies their anisotropic properties in reflection geometry,whereas traditional approaches encounter difficulties and produce inferior and often erroneous results from the violation of reciprocity.In particular,reciprocal polarization imaging provides a consistent characterization of complex media of different thicknesses,accurately measures the optical activity and glucose concentration of turbid media in reflection,and discriminates between cancerous and normal tissue with even stronger contrast than forward measurement.Reciprocal polarization imaging promises broad applications of polarization optics ranging from remote sensing to bio-medicine in reflection geometries,especially in in vivo biomedical imaging,where reflection is the only feasible geometry.展开更多
Root resorption is a significant complication in orthodontic treatment,with thin roots and reciprocal movement being recognized as high-risk factors.This paper reports a case of a 19-year-old female patient who underw...Root resorption is a significant complication in orthodontic treatment,with thin roots and reciprocal movement being recognized as high-risk factors.This paper reports a case of a 19-year-old female patient who underwent orthodontic treatment for dental irregularity.The patient had thin roots in the maxillary lateral incisors 12 and 22.During treatment,tooth 22 experienced reciprocal movement of labial expansion followed by retraction,while tooth 12 adopted passive ligation to reduce reciprocal movement.After 23 months of straight-wire extraction treatment,good occlusal relationships were achieved,but significant root resorption occurred in teeth 12 and 22,with tooth 22 showing more severe resorption.This case confirms the synergistic effect between thin roots and reciprocal movement,demonstrating that thin roots are more sensitive to reciprocal movement stimulation,producing a synergistic amplification effect.Additionally,standardized nursing guidance and patient compliance management play important roles in reducing resorption risk.This case emphasizes the importance of pretreatment risk assessment,individualized treatment strategy formulation,and comprehensive nursing intervention throughout treatment,providing reference for clinical prevention of root resorption.展开更多
The evolution mechanism of the second-order mechanical behaviors under the complex pre-torsion path has not been clarified,which limits its potential application for optimizing precision forming processes of Mg alloy ...The evolution mechanism of the second-order mechanical behaviors under the complex pre-torsion path has not been clarified,which limits its potential application for optimizing precision forming processes of Mg alloy structural components.In this work,the combined loading of reciprocating free-end torsion(FET)and free-rotational tension(FRT)was performed on the extruded AZ31 solid rod with basal fiber texture.The corresponding mechanical response,microstructure evolution,and twinning behaviors were investigated,and the physical mechanism of the second-order behaviors(both the Swift and inverse Swift effects)was discussed.The results indicate that the two-stage deformation of reciprocating torsion is capable of activating tensile twins,effectively refining the surface grains,and thus improving the yield asymmetry.Due to the reverse load,detwinning dominates the deformation of reverse FET(RFET),while detwinning in FRT deformation is caused by the spontaneous rotation of the inverse Swift effect.The twin variants with c-axis tending to extrusion direction(ED)are predisposed to detwinning,and the bimodal texture introduced by FET is degraded.The plastic deformation of RFET is primarily coordinated by basal and prismatic slips.The large strain FRT is dominated by basal slip due to its low SF/CRSS.The interaction between twinning and detwinning dominates the multi-directionality of the Swift effect during reciprocating torsion,and the cumulative effect of strain hardening further enhances the dependence of RFET axial strain on basal slip.The dγ/dεindex successfully captures the evolution of the inverse Swift effect during FRT.The forward rotation of the solid rod is caused by the inversion of the radial residual shear stress field,and the internal stress introduced by the torsional inhomogeneity is compensated.The subsequent reverse rotation is the result of balancing the orientation inhomogeneity and local strain heterogeneity introduced by the shear deformation.The increase in the reverse rotation rate is caused by detwinning.展开更多
Animal adaptation to environmental challenges is a complex process involving intricate interactions between the host genotype and gut microbiome composition.The gut microbiome,highly responsive to external environment...Animal adaptation to environmental challenges is a complex process involving intricate interactions between the host genotype and gut microbiome composition.The gut microbiome,highly responsive to external environmental factors,plays a crucial role in host adaptability and may facilitate local adaptation within species.Concurrently,the genetic background of host populations influences gut microbiome composition,highlighting the bidirectional relationship between host and microbiome.Despite this,our understanding of gut microbiome plasticity and its role in host adaptability remains limited,particularly in reptiles.To clarify this issue,we conducted a reciprocal translocation experiment with gravid females of the Qinghai toad-headed lizards(Phrynocephalus vlangalii)between high-altitude(2?600 m a.s.l.)and superhigh-altitude(3?600 m a.s.l.)environments on Dangjin Mountain of the Qinghai-Xizang Plateau,China.One year later,we assessed the phenotypes and gut microbiomes of their offspring.Results revealed significant plasticity in gut microbiome diversity and structure in response to contrasting elevations.Highaltitude conditions increased diversity,and maternal effects appeared to enable high-altitude lizards to maintain elevated diversity when exposed to superhigh-altitude environments.Additionally,superhigh-altitude lizards displayed distinct gut microbiome structures with notable host specificity,potentially linked to their lower growth rates.Overall,these findings underscore the importance of the gut microbiome in facilitating reptilian adaptation to rapid environmental changes across altitudinal gradients.Furthermore,this study provides critical insights into microbial mechanisms underpinning local adaptation and adaptative plasticity,offering a foundation for future research on host-microbiome interactions in evolutionary and ecological contexts.展开更多
On April 2,the United States announced the implementation of the so-called“reciprocal tariffs”plan.Combined with factors such as the OPEC+plan to increase production starting in May,this led to a continuous plunge i...On April 2,the United States announced the implementation of the so-called“reciprocal tariffs”plan.Combined with factors such as the OPEC+plan to increase production starting in May,this led to a continuous plunge in the benchmark oil prices of WTI and Brent over the subsequent three trading days.Despite the significant impact of the United States’“reciprocal tariffs”plan on the global political and economic landscape,the fundamental dynamics of supply and demand remain the decisive factors in the fluctuations of international oil prices.The current trend of international oil price fluctuations is still primarily driven by the supply side,with both supply and demand factors playing a role.Investment,costs,and resource constraints on the supply side do not allow for a significant increase in crude oil production,while“consumption rigidity”on the demand side does not permit a significant decrease in crude oil demand.As a result,International oil prices are expected to fluctuate in the short term,but a significant decline is unlikely to be sustained in the near to medium term.In this context,Chinese oil companies should focus on four key areas to ensure the security of national oil and gas supplies:first,promoting high-quality increases in domestic oil and gas reserves and production;second,steadily strengthening the acquisition of overseas oil and gas resources;third,continuously driving innovation in oil and gas exploration and development technologies;fourth,enhancing the capacity for domestic oil and gas reserves in an orderly manner.展开更多
This paper introduces a new method based on deep belief networks(DBNs)to integrate intrinsic vibration information and assess the similarity of subspaces established on the Grassmann manifold for intelligent fault dia...This paper introduces a new method based on deep belief networks(DBNs)to integrate intrinsic vibration information and assess the similarity of subspaces established on the Grassmann manifold for intelligent fault diagnosis of a reciprocating compressor(RC).Initially,raw vibration signals undergo empirical mode decomposition to break them down into multiple intrinsic mode functions(IMFs).This operation can reveal inherent vibration patterns of fault and other components hidden in the original signals.Subsequently,features are refined from all the IMFs and concatenated into a high-dimensional representative vector,offering localized and comprehensive insights into RC operation.Through DBN,the fault-sensitive information is further refined from the features to enhance their performance in fault identification.Finally,similarities among subspaces on the Grassmann manifold are computed to match fault types.The efficacy of the method is validated usingfield data.Comparative analysis with traditional approaches for feature dimension reduction,feature extraction,and Euclidean distance-based fault identification underscores the effectiveness and superiority of the proposed method in RC fault diagnosis.展开更多
Satellite communication plays an important role in 6G systems.However,satellite communication systems are more susceptible to intentional or unintentional interference signals than other communication systems because ...Satellite communication plays an important role in 6G systems.However,satellite communication systems are more susceptible to intentional or unintentional interference signals than other communication systems because of their working mechanism of transparent forwarding.For the purpose of eliminating the influence of interference,this paper develops an angle reciprocal interference suppression scheme based on the reconstruction of interferenceplus-noise covariance matrix(ARIS-RIN).Firstly,we utilize the reciprocity between the known beam central angle and the unknown signal arrival angle to estimate the angle of arrival(AOA)of desired signal due to the multi-beam coverage.Then,according to the priori known spatial spectrum distribution,the interferenceplus-noise covariance matrix(INCM)is reconstructed by integrating within the range except the direction of desired signal.In order to correct the estimation bias of the first two steps,the worst-case performance optimization technology is adopted in the process of solving the beamforming vector.Numerical simulation results show that the developed scheme:1)has a higher output signal-to-interference-plus-noise ratio(SINR)under arbitrary signal-to-noise ratio(SNR);2)still has good performance under small snapshots;3)is robuster and easier to be realized when comparing with minimum variance distortionless response(MVDR)and the traditional diagonal loading algorithms.展开更多
After living in China for 33 years,Associate Professor Gu Qingyang of the Lee Kuan Yew School of Public Policy(LKYSPP)at the National University of Singapore(NUS)arrived in Singapore in 1994.Over the past 31 years,he ...After living in China for 33 years,Associate Professor Gu Qingyang of the Lee Kuan Yew School of Public Policy(LKYSPP)at the National University of Singapore(NUS)arrived in Singapore in 1994.Over the past 31 years,he has remained dedicated to building bridges—initially by systematically introducing Singapore’s development experience to China,and later by fostering mutual learning between the two countries.展开更多
To mill fine and well-defined micro-dimpled structures,a machining manner of spiral trajectory tool reciprocating motion,where the tool repeats the process of‘feed milling–retract–cutting feed–feed milling again’...To mill fine and well-defined micro-dimpled structures,a machining manner of spiral trajectory tool reciprocating motion,where the tool repeats the process of‘feed milling–retract–cutting feed–feed milling again’along the spiral trajectory,was proposed.From the kinematics analysis,it is found that the machining quality of micro-dimpled structures is highly dependent on the machining trajectory using spiral trajectory tool reciprocating motion.To reveal this causation,simulation modelling and experimental studies were carried out.A simulation model was developed to quantitatively and qualitatively investigate the influence of the trajectory discretization strategies(constant-angle and constant-arc length)and parameters(discrete angle,discrete arc length,and pitch)on surface texture and residual height of micro-dimpled structures.Subsequently,micro-dimpled structures were milled under different trajectory discretization strategies and parameters with spiral trajectory tool reciprocating motion.A comprehensive comparison between the milled results and simulation analysis was made based on geometry accuracy,surface morphology and surface roughness of milled dimples.Meanwhile,the errors and factors affecting the above three aspects were analyzed.The results demonstrate both the feasibility of the established simulation model and the machining capability of this machining way in milling high-quality micro-dimpled structures.Spiral trajectory tool reciprocating motion provides a new machining way for milling micro-dimpled structures and micro-dimpled functional surfaces.And an appropriate machining trajectory can be generated based on the optimized trajectory parameters,thus contributing to the improvement of machining quality and efficiency.展开更多
Aqueous Zn-I_(2)-Mn hybrid batteries demonstrate enhanced capacity,superior redox reaction kinetics,and prolonged cycle life compared to their Zn-I_(2)and Zn-Mn counterparts,making them promising candidates for grid-s...Aqueous Zn-I_(2)-Mn hybrid batteries demonstrate enhanced capacity,superior redox reaction kinetics,and prolonged cycle life compared to their Zn-I_(2)and Zn-Mn counterparts,making them promising candidates for grid-scale energy storage.Nevertheless,challenges remain in developing multifunctional positive electrode materials and elucidating the mechanistic synergy governing iodine and manganese redox reactions.Herein,we present a high-performance free-standing electrode composed of birnessite(KMnO)nanosheet arrays in situ grown on carbon cloth(CC@KMnO)for constructing a Zn-I_(2)-Mn hybrid battery.Combined theoretical studies and in situ characterizations reveal that CC@KMnO enhances iodine species adsorption,lowers the Gibbs free energy change for iodine reduction,and significantly accelerates I^(-)/I_(3)^(-)/I_(5)^(-)redox kinetics while suppressing polyiodide shuttling and corrosion effects.Synchronously,the Zn I_(2)electrolyte facilitates the dissolution of residual and exfoliated KMnO,thereby improving manganese redox reaction kinetics,reversibility,and enhancing cycling stability.Leveraging this mutually reinforcing effect,the Zn-I_(2)-Mn hybrid battery achieves an impressive areal capacity of2.02 m Ah cm^(-2)and maintains long-term durability over 3600 cycles at 2 mA cm^(-2).This work provides valuable insights into designing efficient and durable hybrid energy storage systems.展开更多
This paper explores the ideological and political education teaching practice in the new media marketing course based on Bandura’s triadic reciprocal determinism.It first analyzes the appropriateness of the triadic r...This paper explores the ideological and political education teaching practice in the new media marketing course based on Bandura’s triadic reciprocal determinism.It first analyzes the appropriateness of the triadic reciprocal determinism,then points out the issues in the ideological and political education of the new media marketing course in terms of“individual,”“behavior,”and“environment,”and finally proposes implementation paths for the ideological and political education teaching in the new media marketing course:curriculum ideological and political education content design based on individual cognition,curriculum ideological and political education participation based on behavioral patterns,and curriculum ideological and political education support based on environmental factors.展开更多
Fine-grained ZK60 alloy was prepared by 2-pass reciprocating extrusion, and the low temperature superplasticity was conducted in a temperature range from 443 to 523 K and an initial strain rate ranging from 3.3×1...Fine-grained ZK60 alloy was prepared by 2-pass reciprocating extrusion, and the low temperature superplasticity was conducted in a temperature range from 443 to 523 K and an initial strain rate ranging from 3.3×10^-4 to 3.3×10-2^s^-1. The results show that the alloy has an equiaxed grain structure with an average grain size of about 5.0μm, and the sizes of broken secondary particles and precipitates are no more than 175 and 50 nm, respectively. The alloy exhibits quasi-superplasticity with a maximum elongation of 270% at 523 K and an initial strain rate of 3.3×10^-4 s^-1. The strain rate sensitivity m is less than 0.2 at 443 and 473 K, and it is 0.42 at 523 K. The apparent activation energies at temperature below 473 K and at 523 K are less than 63.2 and 110.6 kJ/mol, respectively At temperature below 473 K, mainly intragranular sliding contributes to superplastic flow. At 523 K, grain boundary sliding is the dominant deformation mechanism, and dislocation creep controlled by grain boundary diffusion is considered to be the main accommodation mechanism.展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.11934011 and 12274365)National Key R&D Program of China(Grant Nos.2022YFA1402400 and 2022YFA1400043)+1 种基金Zhejiang Provincial Natural Science Foundation of China(Grant No.LR24A040001)Open project of Key Laboratory of Artificial Structures and Quantum Control(Ministry of Education)of Shanghai Jiao Tong University。
文摘Nonreciprocal isolators enable unidirectional light propagation without back-reflection.Typical terahertz isolators require magnetic fields to break the time-reversal symmetry.Herein,we propose a nonmagnetic isolator in the terahertz range based on nonreciprocal graphene plasmons operated in a reflection configuration.The bias voltage generates a drift current in graphene,which breaks the time-reversal symmetry and induces nonreciprocal reflection.The isolator device exhibited a high isolation exceeding 20 d B with an insertion loss of less than 3 d B.Moreover,the bandwidth wit isolation exceeding 20 d B can be broadened five times to 1.7 THz by tuning the carrier density.The indexes,including the isolation,insertion loss and bandwidth of the isolator,show a strong dependence on the drift velocity and mobility of graphene,as well as the air-gap thickness.Our study shows great potential in the burgeoning terahertz technology,where nonmagnetic and electrically tunable isolators are still lacking.
基金National Key Research and Development Program of China(2022YFC3902000)Yunnan Major Scientific and Technological Projects(202202AG050002,202202AG050007)National Natural Science Foundation of China(52166004).
文摘A new stirring method,reciprocating stirring,is developed by incorporating a periodic axial reciprocating motion into conventional stirring.This study employs computational fluid dynamics methods,utilizing volume of fluid and user-defined functions to control and analyze the flow field characteristics in a reciprocating stirred tank.Compared to conventional stirring,reciprocating stirring increases the overall fluid velocity by approximately 7.9%,turbulent kinetic energy(TKE)by 35.9%to 45.6%,and the turbulent dissipation rate by 10.6%to 15.7%.The primary reason is the dynamic integration of multiple flow regions,which enhances fluid interface interactions.Additionally,the study investigates the dynamic evolution of the vortex structure,uncovering the correlation between the impeller's start-stop behavior and the vortex area.The optimal impeller plate designs,forward sine-4/12D and reverse sine-5/12D,were determined based on the effective area of TKE.Reciprocating stirring,in comparison to conventional stirring,enhances secondary flow intensity by 67.3%to 93.7%and shortens mixing time by 56.6%to 173.0%.
文摘The U.S.imposition of high tariffs on Chinese goods has triggered short-term strains on China’s exports.At the same time,it has also accelerated its strategic pivot toward technological self-reliance,regional integration,and domestic demand expansion.
基金upported by the Natural Science Foundation of Zhejiang Province(Grant No.LZ16H180002)the National Natural Science Foundation of China(Grant No.61905181)+1 种基金the Wenzhou Municipal Science and Technology Bureau(Grant No.ZS2017022)the National Science Foundation of the U.S.(Grant No.1607664).
文摘The vectorial evolution of light polarization can reveal the microstructure and anisotropy of a medium beyond what can be obtained from measuring light intensity alone.However,polarization imaging in reflection geometry,which is ubiquitous and often preferred in diverse applications,has often suffered from poor and even incorrect characterization of anisotropic media.We present reciprocal polarization imaging of complex media in reflection geometry with the reciprocal polar decomposition of backscattering Mueller matrices enforcing reciprocity.We demonstrate that reciprocal polarization imaging of complex chiral and anisotropic media ac-curately quantifies their anisotropic properties in reflection geometry,whereas traditional approaches encounter difficulties and produce inferior and often erroneous results from the violation of reciprocity.In particular,reciprocal polarization imaging provides a consistent characterization of complex media of different thicknesses,accurately measures the optical activity and glucose concentration of turbid media in reflection,and discriminates between cancerous and normal tissue with even stronger contrast than forward measurement.Reciprocal polarization imaging promises broad applications of polarization optics ranging from remote sensing to bio-medicine in reflection geometries,especially in in vivo biomedical imaging,where reflection is the only feasible geometry.
文摘Root resorption is a significant complication in orthodontic treatment,with thin roots and reciprocal movement being recognized as high-risk factors.This paper reports a case of a 19-year-old female patient who underwent orthodontic treatment for dental irregularity.The patient had thin roots in the maxillary lateral incisors 12 and 22.During treatment,tooth 22 experienced reciprocal movement of labial expansion followed by retraction,while tooth 12 adopted passive ligation to reduce reciprocal movement.After 23 months of straight-wire extraction treatment,good occlusal relationships were achieved,but significant root resorption occurred in teeth 12 and 22,with tooth 22 showing more severe resorption.This case confirms the synergistic effect between thin roots and reciprocal movement,demonstrating that thin roots are more sensitive to reciprocal movement stimulation,producing a synergistic amplification effect.Additionally,standardized nursing guidance and patient compliance management play important roles in reducing resorption risk.This case emphasizes the importance of pretreatment risk assessment,individualized treatment strategy formulation,and comprehensive nursing intervention throughout treatment,providing reference for clinical prevention of root resorption.
基金supported by the National Natural Science Foundation of China(Nos.51771166,52225101)Fundamental Research Funds for the Central Universities(No.2023CDJYXTD-002)+1 种基金Cultivation Project for Basic Research and In-novation of Yanshan University(No.2021LGZD002)Project of State Key Laboratory of Materials Processing and Die&Mould Technology(No.P2023-004).
文摘The evolution mechanism of the second-order mechanical behaviors under the complex pre-torsion path has not been clarified,which limits its potential application for optimizing precision forming processes of Mg alloy structural components.In this work,the combined loading of reciprocating free-end torsion(FET)and free-rotational tension(FRT)was performed on the extruded AZ31 solid rod with basal fiber texture.The corresponding mechanical response,microstructure evolution,and twinning behaviors were investigated,and the physical mechanism of the second-order behaviors(both the Swift and inverse Swift effects)was discussed.The results indicate that the two-stage deformation of reciprocating torsion is capable of activating tensile twins,effectively refining the surface grains,and thus improving the yield asymmetry.Due to the reverse load,detwinning dominates the deformation of reverse FET(RFET),while detwinning in FRT deformation is caused by the spontaneous rotation of the inverse Swift effect.The twin variants with c-axis tending to extrusion direction(ED)are predisposed to detwinning,and the bimodal texture introduced by FET is degraded.The plastic deformation of RFET is primarily coordinated by basal and prismatic slips.The large strain FRT is dominated by basal slip due to its low SF/CRSS.The interaction between twinning and detwinning dominates the multi-directionality of the Swift effect during reciprocating torsion,and the cumulative effect of strain hardening further enhances the dependence of RFET axial strain on basal slip.The dγ/dεindex successfully captures the evolution of the inverse Swift effect during FRT.The forward rotation of the solid rod is caused by the inversion of the radial residual shear stress field,and the internal stress introduced by the torsional inhomogeneity is compensated.The subsequent reverse rotation is the result of balancing the orientation inhomogeneity and local strain heterogeneity introduced by the shear deformation.The increase in the reverse rotation rate is caused by detwinning.
基金supported by the National Natural Science Foundation of China (31861143023,31872252)Strategic Priority Research Program of the Chinese Academy of Sciences (XDA20050201)。
文摘Animal adaptation to environmental challenges is a complex process involving intricate interactions between the host genotype and gut microbiome composition.The gut microbiome,highly responsive to external environmental factors,plays a crucial role in host adaptability and may facilitate local adaptation within species.Concurrently,the genetic background of host populations influences gut microbiome composition,highlighting the bidirectional relationship between host and microbiome.Despite this,our understanding of gut microbiome plasticity and its role in host adaptability remains limited,particularly in reptiles.To clarify this issue,we conducted a reciprocal translocation experiment with gravid females of the Qinghai toad-headed lizards(Phrynocephalus vlangalii)between high-altitude(2?600 m a.s.l.)and superhigh-altitude(3?600 m a.s.l.)environments on Dangjin Mountain of the Qinghai-Xizang Plateau,China.One year later,we assessed the phenotypes and gut microbiomes of their offspring.Results revealed significant plasticity in gut microbiome diversity and structure in response to contrasting elevations.Highaltitude conditions increased diversity,and maternal effects appeared to enable high-altitude lizards to maintain elevated diversity when exposed to superhigh-altitude environments.Additionally,superhigh-altitude lizards displayed distinct gut microbiome structures with notable host specificity,potentially linked to their lower growth rates.Overall,these findings underscore the importance of the gut microbiome in facilitating reptilian adaptation to rapid environmental changes across altitudinal gradients.Furthermore,this study provides critical insights into microbial mechanisms underpinning local adaptation and adaptative plasticity,offering a foundation for future research on host-microbiome interactions in evolutionary and ecological contexts.
文摘On April 2,the United States announced the implementation of the so-called“reciprocal tariffs”plan.Combined with factors such as the OPEC+plan to increase production starting in May,this led to a continuous plunge in the benchmark oil prices of WTI and Brent over the subsequent three trading days.Despite the significant impact of the United States’“reciprocal tariffs”plan on the global political and economic landscape,the fundamental dynamics of supply and demand remain the decisive factors in the fluctuations of international oil prices.The current trend of international oil price fluctuations is still primarily driven by the supply side,with both supply and demand factors playing a role.Investment,costs,and resource constraints on the supply side do not allow for a significant increase in crude oil production,while“consumption rigidity”on the demand side does not permit a significant decrease in crude oil demand.As a result,International oil prices are expected to fluctuate in the short term,but a significant decline is unlikely to be sustained in the near to medium term.In this context,Chinese oil companies should focus on four key areas to ensure the security of national oil and gas supplies:first,promoting high-quality increases in domestic oil and gas reserves and production;second,steadily strengthening the acquisition of overseas oil and gas resources;third,continuously driving innovation in oil and gas exploration and development technologies;fourth,enhancing the capacity for domestic oil and gas reserves in an orderly manner.
文摘This paper introduces a new method based on deep belief networks(DBNs)to integrate intrinsic vibration information and assess the similarity of subspaces established on the Grassmann manifold for intelligent fault diagnosis of a reciprocating compressor(RC).Initially,raw vibration signals undergo empirical mode decomposition to break them down into multiple intrinsic mode functions(IMFs).This operation can reveal inherent vibration patterns of fault and other components hidden in the original signals.Subsequently,features are refined from all the IMFs and concatenated into a high-dimensional representative vector,offering localized and comprehensive insights into RC operation.Through DBN,the fault-sensitive information is further refined from the features to enhance their performance in fault identification.Finally,similarities among subspaces on the Grassmann manifold are computed to match fault types.The efficacy of the method is validated usingfield data.Comparative analysis with traditional approaches for feature dimension reduction,feature extraction,and Euclidean distance-based fault identification underscores the effectiveness and superiority of the proposed method in RC fault diagnosis.
基金supported by the National Natural Science Foundation of China under Grants No.61671367 and 62471381the Research Foundation of Science and Technology on Communication Networks Laboratory,and the National Key Laboratory of Wireless Communications Foundation under Grant No.IFN202401.
文摘Satellite communication plays an important role in 6G systems.However,satellite communication systems are more susceptible to intentional or unintentional interference signals than other communication systems because of their working mechanism of transparent forwarding.For the purpose of eliminating the influence of interference,this paper develops an angle reciprocal interference suppression scheme based on the reconstruction of interferenceplus-noise covariance matrix(ARIS-RIN).Firstly,we utilize the reciprocity between the known beam central angle and the unknown signal arrival angle to estimate the angle of arrival(AOA)of desired signal due to the multi-beam coverage.Then,according to the priori known spatial spectrum distribution,the interferenceplus-noise covariance matrix(INCM)is reconstructed by integrating within the range except the direction of desired signal.In order to correct the estimation bias of the first two steps,the worst-case performance optimization technology is adopted in the process of solving the beamforming vector.Numerical simulation results show that the developed scheme:1)has a higher output signal-to-interference-plus-noise ratio(SINR)under arbitrary signal-to-noise ratio(SNR);2)still has good performance under small snapshots;3)is robuster and easier to be realized when comparing with minimum variance distortionless response(MVDR)and the traditional diagonal loading algorithms.
文摘After living in China for 33 years,Associate Professor Gu Qingyang of the Lee Kuan Yew School of Public Policy(LKYSPP)at the National University of Singapore(NUS)arrived in Singapore in 1994.Over the past 31 years,he has remained dedicated to building bridges—initially by systematically introducing Singapore’s development experience to China,and later by fostering mutual learning between the two countries.
基金co-supported the National Natural Science Foundation of China(No.52235010)the Heilongjiang Postdoctoral Fund(No.LBH-Z22136)the New Era Longjiang Excellent Master and Doctoral Dissertation Fund(No.LJYXL2022-057).
文摘To mill fine and well-defined micro-dimpled structures,a machining manner of spiral trajectory tool reciprocating motion,where the tool repeats the process of‘feed milling–retract–cutting feed–feed milling again’along the spiral trajectory,was proposed.From the kinematics analysis,it is found that the machining quality of micro-dimpled structures is highly dependent on the machining trajectory using spiral trajectory tool reciprocating motion.To reveal this causation,simulation modelling and experimental studies were carried out.A simulation model was developed to quantitatively and qualitatively investigate the influence of the trajectory discretization strategies(constant-angle and constant-arc length)and parameters(discrete angle,discrete arc length,and pitch)on surface texture and residual height of micro-dimpled structures.Subsequently,micro-dimpled structures were milled under different trajectory discretization strategies and parameters with spiral trajectory tool reciprocating motion.A comprehensive comparison between the milled results and simulation analysis was made based on geometry accuracy,surface morphology and surface roughness of milled dimples.Meanwhile,the errors and factors affecting the above three aspects were analyzed.The results demonstrate both the feasibility of the established simulation model and the machining capability of this machining way in milling high-quality micro-dimpled structures.Spiral trajectory tool reciprocating motion provides a new machining way for milling micro-dimpled structures and micro-dimpled functional surfaces.And an appropriate machining trajectory can be generated based on the optimized trajectory parameters,thus contributing to the improvement of machining quality and efficiency.
基金financially supported by the National Natural Science Foundation of China(22302177)the Key Science and Technology Project of Jinhua City(2024-1-004)the Self Designed Scientific Research of Zhejiang Normal University(2021ZS0604)。
文摘Aqueous Zn-I_(2)-Mn hybrid batteries demonstrate enhanced capacity,superior redox reaction kinetics,and prolonged cycle life compared to their Zn-I_(2)and Zn-Mn counterparts,making them promising candidates for grid-scale energy storage.Nevertheless,challenges remain in developing multifunctional positive electrode materials and elucidating the mechanistic synergy governing iodine and manganese redox reactions.Herein,we present a high-performance free-standing electrode composed of birnessite(KMnO)nanosheet arrays in situ grown on carbon cloth(CC@KMnO)for constructing a Zn-I_(2)-Mn hybrid battery.Combined theoretical studies and in situ characterizations reveal that CC@KMnO enhances iodine species adsorption,lowers the Gibbs free energy change for iodine reduction,and significantly accelerates I^(-)/I_(3)^(-)/I_(5)^(-)redox kinetics while suppressing polyiodide shuttling and corrosion effects.Synchronously,the Zn I_(2)electrolyte facilitates the dissolution of residual and exfoliated KMnO,thereby improving manganese redox reaction kinetics,reversibility,and enhancing cycling stability.Leveraging this mutually reinforcing effect,the Zn-I_(2)-Mn hybrid battery achieves an impressive areal capacity of2.02 m Ah cm^(-2)and maintains long-term durability over 3600 cycles at 2 mA cm^(-2).This work provides valuable insights into designing efficient and durable hybrid energy storage systems.
基金Research on the Teaching Practice of Ideological and Political Education in the New Media Marketing Course from a Three-Way Interactive Perspective under the 2024 Special Project for Curriculum-Based Ideological and Political Education at Hebei Normal University of Science and Technology(PX-2424813)Research on the Teaching Incentive of Xi Jinping’s Important Thoughts on Youth Work in Addressing College Students’Sense of“Powerlessness”under the 2023 General Teaching Research Project at Hebei Normal University of Science and Technology(PX-1923438)。
文摘This paper explores the ideological and political education teaching practice in the new media marketing course based on Bandura’s triadic reciprocal determinism.It first analyzes the appropriateness of the triadic reciprocal determinism,then points out the issues in the ideological and political education of the new media marketing course in terms of“individual,”“behavior,”and“environment,”and finally proposes implementation paths for the ideological and political education teaching in the new media marketing course:curriculum ideological and political education content design based on individual cognition,curriculum ideological and political education participation based on behavioral patterns,and curriculum ideological and political education support based on environmental factors.
基金Project (50271054) supported by National Natural Science Foundation of ChinaProject (20070700003) supported by Ph.D. Programs Foundation of Ministry of Education of China+1 种基金Project (102102210031) supported by Science and Technologies Foundation of Henan,ChinaProject (2010A430008) supported by Natural Science Foundation of Henan Educational Committee,China
文摘Fine-grained ZK60 alloy was prepared by 2-pass reciprocating extrusion, and the low temperature superplasticity was conducted in a temperature range from 443 to 523 K and an initial strain rate ranging from 3.3×10^-4 to 3.3×10-2^s^-1. The results show that the alloy has an equiaxed grain structure with an average grain size of about 5.0μm, and the sizes of broken secondary particles and precipitates are no more than 175 and 50 nm, respectively. The alloy exhibits quasi-superplasticity with a maximum elongation of 270% at 523 K and an initial strain rate of 3.3×10^-4 s^-1. The strain rate sensitivity m is less than 0.2 at 443 and 473 K, and it is 0.42 at 523 K. The apparent activation energies at temperature below 473 K and at 523 K are less than 63.2 and 110.6 kJ/mol, respectively At temperature below 473 K, mainly intragranular sliding contributes to superplastic flow. At 523 K, grain boundary sliding is the dominant deformation mechanism, and dislocation creep controlled by grain boundary diffusion is considered to be the main accommodation mechanism.
