Many networks exhibit the core/periphery structure.Core/periphery structure is a type of meso-scale structure that consists of densely connected core nodes and sparsely connected peripheral nodes.Core nodes tend to be...Many networks exhibit the core/periphery structure.Core/periphery structure is a type of meso-scale structure that consists of densely connected core nodes and sparsely connected peripheral nodes.Core nodes tend to be well-connected,both among themselves and to peripheral nodes,which tend not to be well-connected to other nodes.In this brief report,we propose a new method to detect the core of a network by the centrality of each node.It is discovered that such nodes with non-negative centralities often consist in the core of the networks.The simulation is carried out on different real networks.The results are checked by the objective function.The checked results may show the effectiveness of the simulation results by the centralities of the nodes on the real networks.Furthermore,we discuss the characters of networks with the single core/periphery structure and point out the scope of the application of our method at the end of this paper.展开更多
Curved shells are increasingly utilized in applied engineering due to their shared characteristics with other sandwich structures,flexibility,and attractive appearance.However,the inability of controlling and regulati...Curved shells are increasingly utilized in applied engineering due to their shared characteristics with other sandwich structures,flexibility,and attractive appearance.However,the inability of controlling and regulating vibrations and destroying them afterward is a challenge to scientists.In this paper,the curve shell equations and a linear quadratic regulator are adopted for the state feedback design to manage the structure vibrations in state space forms.A five-layer sandwich doubly curved micro-composite shell,comprising two piezoelectric layers for the sensor and actuator,is modeled by the fourth-order shear deformation theory.The core(honeycomb,truss,and corrugated)is analyzed for the bearing of transverse shear forces.The results show that the honeycomb core has a greater effect on the vibrations.When the parameters related to the core and the weight percentage of graphene increase,the frequency increases.The uniform distribution of graphene platelets results in the lowest natural frequency while the natural frequency increases.Furthermore,without taking into account the piezoelectric layers,the third-order shear deformation theory(TSDT)and fourth-order shear deformation theory(FOSDT)align closely.However,when the piezoelectric layers are incorporated,these two theories diverge significantly,with the frequencies in the FOSDT being lower than those in the TSDT.展开更多
Curcumin is a natural polyphenol that is used in various traditional medicines.However,its inherent properties,such as its rapid degradation and metabolism,low bioavailability,and short half-life,are serious problems ...Curcumin is a natural polyphenol that is used in various traditional medicines.However,its inherent properties,such as its rapid degradation and metabolism,low bioavailability,and short half-life,are serious problems that must be resolved.To this end,a drug carrier incorporating natural magnetic cores in a zeolite framework was developed and applied to the loading of curcumin in ethanol solutions.In this system,curcumin is encapsulated in a zeolite Na(ZNA)magnetic core–shell structure(Fe@Si/ZNA),which can be easily synthesized using an in situ method.Synthesis of Fe_(3)O_(4) nanoparticles was carried out from natural materials using a co-precipitation method.Analysis of the prepared magnetic core–shell structures and composites was carried out using vibrating-sample magnetometery,Fourier transform infrared spectroscopy,transmission electron microscopy,and x-ray diffraction.The cumulative loading of curcumin in the ZNA composite with 9%nanoparticles was found to reach 90.70%with a relatively long half-life of 32.49 min.Stability tests of curcumin loading in the composite showed that adding magnetic particles to the zeolite framework also increased the stability of the composite structure.Adsorption kinetics and isotherm studies also found that the system follows the pseudo-second-order and Langmuir isotherm models.展开更多
Commercial sterility does not guarantee the sustained stability of ultrahigh temperature(UHT)milk over 6 months shelf life.We explore the microbiota presented in normal(SZ)and quality deteriorated UHT milk(QY and WY)p...Commercial sterility does not guarantee the sustained stability of ultrahigh temperature(UHT)milk over 6 months shelf life.We explore the microbiota presented in normal(SZ)and quality deteriorated UHT milk(QY and WY)products from the same brand.Based on high-throughput sequencing research results,11 phyla and 54 genera were identified as dominant microbiota.Pseudomonas,Streptococcus,and Acinetobacter as core functional microbiota significantly influenced the UHT milk quality properties.Moreover,principal component analysis(PCA)and multivariate analyses were used to examine the quality characteristics,including 11 physicochemical parameters,10 fatty acids,and 2 enzyme activities,in normal and quality deteriorated UHT milk.We found that the abundance of Pseudomonas increased in quality deteriorated milk(WY)and showed a significant positive correlation with heat-resistant protease content.Acinetobacter in quality deteriorated milk(QY)also considerably contributed to the content of heat-resistant lipase,which resulted in spoilage deterioration of UHT milk.展开更多
The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around...The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate.展开更多
BACKGROUND The overlap of imaging manifestations among distinct splenic lesions gives rise to a diagnostic dilemma.Consequently,a definitive diagnosis primarily relies on his-tological results.The ultrasound(US)-guide...BACKGROUND The overlap of imaging manifestations among distinct splenic lesions gives rise to a diagnostic dilemma.Consequently,a definitive diagnosis primarily relies on his-tological results.The ultrasound(US)-guided coaxial core needle biopsy(CNB)not only procures sufficient tissue to help clarify the diagnosis,but reduces the incidence of puncture-related complications.CASE SUMMARY A 41-year-old female,with a history of pulmonary tuberculosis,was admitted to our hospital with multiple indeterminate splenic lesions.Gray-scale ultrasono-graphy demonstrated splenomegaly with numerous well-defined hypoechoic ma-sses.Abdominal contrast-enhanced computed tomography(CT)showed an en-larged spleen with multiple irregular-shaped,peripherally enhancing,hypodense lesions.Positron emission CT revealed numerous abnormal hyperglycemia foci.These imaging findings strongly indicated the possibility of infectious disease as the primary concern,with neoplastic lesions requiring exclusion.To obtain the precise pathological diagnosis,the US-guided coaxial CNB of the spleen was ca-rried out.The patient did not express any discomfort during the procedure.CONCLUSION Percutaneous US-guided coaxial CNB is an excellent and safe option for obtaining precise splenic tissue samples,as it significantly enhances sample yield for exact pathological analysis with minimum trauma to the spleen parenchyma and sur-rounding tissue.展开更多
The core competencies of college students can influence their further learning,employment,and personal development.This paper explores college English teaching from the three aspects of core competencies:cultural foun...The core competencies of college students can influence their further learning,employment,and personal development.This paper explores college English teaching from the three aspects of core competencies:cultural foundation,self-development,and social participation.Adapting to the challenges posed by the new era for the cultivation of foreign language talents,the paper aims to improve students’cultural literacy,independent learning,the ability of problem discovery and problem solving,and critical cultural thinking,so as to make them more competitive in employment and entrepreneurship.展开更多
The main purpose of this paper is to investigate the effect of core eccentricity on the structural behavior of concrete tall buildings.Concrete buildings of 55 floors with plan dimensions 48.0×48.0 m2 were invest...The main purpose of this paper is to investigate the effect of core eccentricity on the structural behavior of concrete tall buildings.Concrete buildings of 55 floors with plan dimensions 48.0×48.0 m2 were investigated.Three cases of main core locations are studied:centric(A),eccentric by one sixth(B)and one third(C)of building width.The three-dimensional finite element method has been used in conducting structural analysis through ETABS software.Gravity and lateral(wind and seismic)loadings are applied to all building cases.It has been concluded that the core location is the prime parameter governing the structural behavior of tall buildings.Although the first two cases(A,B)have acceptable and similar structural behaviors conforming to code limits,in the third case(C),the building behavior came beyond code limits.The author introduced remedial action by adding two secondary cores in the opposite direction of the main core(C-R)to restore the building behavior to the code limits.The results of this action were satisfactory.展开更多
The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigate...The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigated.The current study aims to carry out a dynamic analysis on the sandwich beam when the impactor hits the top face sheet with an initial velocity.For the layer analysis,the high-order shear deformation theory(HSDT)and Frostig's second model for the displacement fields of the core layer are used.The classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of time.In order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the LVI.Finite element(FE)simulations are conducted by means of the ABAQUS software.The effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed.展开更多
Socialist core values are the concentrated expression and highly condensed values of the state,society,and individuals.They are also the embodiment of the values and spiritual consensus and pursuit in the life of the ...Socialist core values are the concentrated expression and highly condensed values of the state,society,and individuals.They are also the embodiment of the values and spiritual consensus and pursuit in the life of the state and society.This article analyzes and summarizes the research results on the identification of socialist core values in China in recent years,mainly sorting out aspects such as the significance of identification,the dialectical relationship between identification and practice,differences in identification levels among different groups,and paths to enhance identification.Finally,suggestions for further deepening future research are proposed.展开更多
Vocational undergraduate education has evolved from its initial stages to a full-scale implementation,achieving historic milestones along the way.However,its appeal still lags significantly behind that of general educ...Vocational undergraduate education has evolved from its initial stages to a full-scale implementation,achieving historic milestones along the way.However,its appeal still lags significantly behind that of general education.The development of students’core competencies in vocational undergraduate education faces several challenges,including the need for improvements in top-level design,a stronger focus on connotation development,and an upgraded linkage mechanism.To address these issues,it is suggested to refine the top-level design,enhance internal motivation,and build a robust vocational education ecosystem.展开更多
Background:The Internet plus nursing service program is being piloted in China,which has become a new home nursing service model led by nurses.To enable safe and effective homecare service delivery,nurses working in t...Background:The Internet plus nursing service program is being piloted in China,which has become a new home nursing service model led by nurses.To enable safe and effective homecare service delivery,nurses working in the program need a high level of competency.However,the content of these core competencies and the training needs of nurses for Internet plus nursing services are still unknown.Aim:To describe nurses’perceptions of core competencies and training needs to work in the Internet plus nursing service program,thereby providing a reference for the development of training programs.Methods:A qualitative descriptive study using semi-structured interviews was conducted on 15 nurses with experience of working in the Internet plus nursing service program.Interviews were audio-recorded and transcribed verbatim,and the data were analyzed using thematic analysis.Results:Core competencies involved comprehensive assessment competence,direct care practice competence,health education and consulting competence,risk estimation and response competence,and communication competence.Training needs involved complex operational items,knowledge of chronic disease management,professional communication,risk identification and response,nursing standards,norms,and procedures,and utilization of information technology.Conclusions:The training system may be developed based on nurses’core competencies and their training needs to promote professional development of the Internet plus nursing service.展开更多
The breakthrough of key core technology is a theoretical and practical strategic issue to realize the rise of the country.This paper analyzes the concept of key core technology and its breakthrough and analyzes its ch...The breakthrough of key core technology is a theoretical and practical strategic issue to realize the rise of the country.This paper analyzes the concept of key core technology and its breakthrough and analyzes its characteristics.Based on the perspective of participants,this paper summarizes the influencing factors of key core technology breakthroughs in enterprises:internal and external enterprises,universities and scientific research institutions,and government.This paper expands the relevant research on key core technology breakthroughs and provides inspiration for enterprises to carry out key core technology research and breakthrough practices.展开更多
The effect of neutral pressure on the blue core in Ar helicon plasma under an inhomogeneous magnetic field was investigated in this work.The neutral pressure was set to 0.08 Pa,0.36 Pa,and 0.68 Pa.A Nikon camera,inten...The effect of neutral pressure on the blue core in Ar helicon plasma under an inhomogeneous magnetic field was investigated in this work.The neutral pressure was set to 0.08 Pa,0.36 Pa,and 0.68 Pa.A Nikon camera,intensified charge-coupled device(ICCD),optical emission spectrometer(OES),and Langmuir probe were used to diagnose the blue core in helicon plasma.Helicon plasma discharges experienced density jumps from the E mode,H mode to W mode before power just rose to 200 W.The plasma density increased and maintained a central peak with the increase of neutral pressure.However,the brightness of the blue core gradually decreased.It is demonstrated that the relative intensity of Ar II spectral lines and the ionization rate in the central area were reduced.Radial electron temperature profiles were flattened and became hollow as neutral pressure increased.It is demonstrated that increasing the neutral pressure weakened the central heating efficiency dominated by the helicon wave and strengthened the edge heating efficiency governed by the TG wave and skin effect.Therefore,the present experiment successfully reveals how the neutral pressure affects the heating mechanism of helicon plasma in an inhomogeneous magnetic field.展开更多
In this work,we perform a Bayesian inference of the crust-core transition density ρ_(t) of neutron stars based on the neutron-star radius and neutron-skin thickness data using a thermodynamical method.Uniform and Gau...In this work,we perform a Bayesian inference of the crust-core transition density ρ_(t) of neutron stars based on the neutron-star radius and neutron-skin thickness data using a thermodynamical method.Uniform and Gaussian distributions for the ρ_(t) prior were adopted in the Bayesian approach.It has a larger probability of having values higher than 0.1 fm^(−3) for ρ_(t) as the uniform prior and neutron-star radius data were used.This was found to be controlled by the curvature K_(sym) of the nuclear symmetry energy.This phenomenon did not occur if K_(sym) was not extremely negative,namely,K_(sym)>−200 MeV.The value ofρ_(t) obtained was 0.075_(−0.01)^(+0.005) fm^(−3) at a confidence level of 68%when both the neutron-star radius and neutron-skin thickness data were considered.Strong anti-correlations were observed between ρ_(t),slope L,and curvature of the nuclear symmetry energy.The dependence of the three L-K_(sym) correlations predicted in the literature on crust-core density and pressure was quantitatively investigated.The most probable value of 0.08 fm^(−3) for ρ_(t) was obtained from the L-K_(sym) relationship proposed by Holt et al.while larger values were preferred for the other two relationships.展开更多
The rotation of the Earth's liquid core creates the Nearly Diurnal Free Wobble (NDFW). It is one of the problems of researching the Earth's liquid core for us to retrieve the parameters of the Earth's Free...The rotation of the Earth's liquid core creates the Nearly Diurnal Free Wobble (NDFW). It is one of the problems of researching the Earth's liquid core for us to retrieve the parameters of the Earth's Free Core Nutation (FCN),from the Earth's liquid core resonance of gravity tide waves on the diurnal frequency band. Since 1987, some scientists in many different countries have come to calculate the parameters of FCN by using the observational data of gravity tide waves on the diumal frequency band. They basically followed the Stacking method, which needed five diurnal waves for the resolution. In this paper, authors introduced the Aky-Btk value method with clearly geometrical meaning as a new method, which only requires three very high signal-noise-ratio waves o1, K1 and P1 for the resolution. Authors chose the observational data of the three superconducting gravimeter stations respectively located in Cantley of Canada, Wuhan of China and Brussels of Belgium, to compute the parameters of FCN. It was the first time that the observational results of the parameters of FCN obtained from gravitational tide were in accord with the parameters of FCN gained from VLBI since 1987.展开更多
The elasto-gravitational deformation response of the Earths solid parts to the perturbations of the pressure and gravity on the core-mantle boundary (CMB) and the solid inner core boundary (ICB), due to the dynamical ...The elasto-gravitational deformation response of the Earths solid parts to the perturbations of the pressure and gravity on the core-mantle boundary (CMB) and the solid inner core boundary (ICB), due to the dynamical behaviors of the fluid outer core (FOC), is discussed. The internal load Love numbers, which are formulized in a general form in this study, are employed to describe the Earths deformation. The preliminary reference Earth model (PREM) is used as an example to calculate the internal load Love numbers on the Earths surface, CMB and ICB, respectively. The characteristics of the Earths deformation variation with the depth and the perturbation periods on the boundaries of the FOC are also investigated. The numerical results indicate that the internal load Love numbers decrease quickly with the increasing degree of the spherical harmonics of the displacement and depend strongly on the perturbation frequencies, especially on the high frequencies. The results, obtained in this work, can be used to construct the boundary conditions for the core dynamics of the long-period oscillations of the Earths fluid outer core.展开更多
In this study,the characteristics of azimuthally asymmetric equivalent potential temperature(θ_(e))distributions in the outer core of tropical cyclones(TCs)encountering weak and strong vertical wind shear are examine...In this study,the characteristics of azimuthally asymmetric equivalent potential temperature(θ_(e))distributions in the outer core of tropical cyclones(TCs)encountering weak and strong vertical wind shear are examined using a Lagrangian trajectory method.Evaporatively forced downdrafts in the outer rainbands can transport low-entropy air downward,resulting in the lowestθ_(e)in the downshear-left boundary layer.Quantitative estimations ofθ_(e)recovery indicate that air parcels,especially those originating from the downshear-left outer core,can gradually revive from a low entropy state through surface enthalpy fluxes as the parcels move cyclonically.As a result,the maximumθ_(e)is observed in the downshear-right quadrant of a highly sheared TC.The trajectory analyses also indicate that parcels that move upward in the outer rainbands and those that travel through the inner core due to shear make a dominant contribution to the midlevel enhancement ofθ_(e)in the downshear-left outer core.In particular,the former plays a leading role in suchθ_(e)enhancements,while the latter plays a secondary role.As a result,moist potential stability occurs in the middle-to-lower troposphere in the downshear-left outer core.展开更多
Material composition and structural design are important factors influencing the electromagnetic wave(EMW)absorption performance of materials.To alleviate the impedance mismatch attributed to the high dielectric const...Material composition and structural design are important factors influencing the electromagnetic wave(EMW)absorption performance of materials.To alleviate the impedance mismatch attributed to the high dielectric constant of Ti_(3)C_(2)T_(x)MXene,we have successfully synthesized core‐shell structured SiO_(2)@MXene@MoS_(2)nanospheres.This architecture,comprising SiO_(2)as the core,MXene as the intermediate layer,and MoS_(2)as the outer shell,is achieved through an electrostatic self‐assembly method combined with a hydrothermal process.This complex core‐shell structure not only provides a variety of loss mechanisms that effectively dissipate electromagnetic energy but also prevents self‐aggregation of MXene and MoS_(2)nanosheets.Notably,the synergistic combination of SiO_(2)and MoS_(2)with highly conductive MXene enables the suitable dielectric constant of the composites,ensuring optimal impedance matching.Therefore,the core‐shell structured SiO_(2)@MXene@MoS_(2)nanospheres exhibit excellent EMW absorption performance,featuring a remarkable minimum reflection loss(RL_(min))of−52.11 dB(2.4 mm).It is noteworthy that these nanospheres achieve an ultra‐wide effective absorption bandwidth(EAB)of 6.72 GHz.This work provides a novel approach for designing and synthesizing high‐performance EMW absorbers characterized by“wide bandwidth and strong reflection loss.”展开更多
基金Project supported by the National Natural Science Foundation of China (Gant No.11872323)。
文摘Many networks exhibit the core/periphery structure.Core/periphery structure is a type of meso-scale structure that consists of densely connected core nodes and sparsely connected peripheral nodes.Core nodes tend to be well-connected,both among themselves and to peripheral nodes,which tend not to be well-connected to other nodes.In this brief report,we propose a new method to detect the core of a network by the centrality of each node.It is discovered that such nodes with non-negative centralities often consist in the core of the networks.The simulation is carried out on different real networks.The results are checked by the objective function.The checked results may show the effectiveness of the simulation results by the centralities of the nodes on the real networks.Furthermore,we discuss the characters of networks with the single core/periphery structure and point out the scope of the application of our method at the end of this paper.
基金the Iranian Nanotechnology Development Committee for their financial supportUniversity of Kashan for supporting this work by Grant No. 1223097/10the micro and nanomechanics laboratory by Grant No. 14022023/5
文摘Curved shells are increasingly utilized in applied engineering due to their shared characteristics with other sandwich structures,flexibility,and attractive appearance.However,the inability of controlling and regulating vibrations and destroying them afterward is a challenge to scientists.In this paper,the curve shell equations and a linear quadratic regulator are adopted for the state feedback design to manage the structure vibrations in state space forms.A five-layer sandwich doubly curved micro-composite shell,comprising two piezoelectric layers for the sensor and actuator,is modeled by the fourth-order shear deformation theory.The core(honeycomb,truss,and corrugated)is analyzed for the bearing of transverse shear forces.The results show that the honeycomb core has a greater effect on the vibrations.When the parameters related to the core and the weight percentage of graphene increase,the frequency increases.The uniform distribution of graphene platelets results in the lowest natural frequency while the natural frequency increases.Furthermore,without taking into account the piezoelectric layers,the third-order shear deformation theory(TSDT)and fourth-order shear deformation theory(FOSDT)align closely.However,when the piezoelectric layers are incorporated,these two theories diverge significantly,with the frequencies in the FOSDT being lower than those in the TSDT.
基金funding from the Ministry of Education,Culture,Research,and Technology,Indonesia,through the PDKN Research Grant with Contract No.041/E5/PG.02.00.PL/2023.
文摘Curcumin is a natural polyphenol that is used in various traditional medicines.However,its inherent properties,such as its rapid degradation and metabolism,low bioavailability,and short half-life,are serious problems that must be resolved.To this end,a drug carrier incorporating natural magnetic cores in a zeolite framework was developed and applied to the loading of curcumin in ethanol solutions.In this system,curcumin is encapsulated in a zeolite Na(ZNA)magnetic core–shell structure(Fe@Si/ZNA),which can be easily synthesized using an in situ method.Synthesis of Fe_(3)O_(4) nanoparticles was carried out from natural materials using a co-precipitation method.Analysis of the prepared magnetic core–shell structures and composites was carried out using vibrating-sample magnetometery,Fourier transform infrared spectroscopy,transmission electron microscopy,and x-ray diffraction.The cumulative loading of curcumin in the ZNA composite with 9%nanoparticles was found to reach 90.70%with a relatively long half-life of 32.49 min.Stability tests of curcumin loading in the composite showed that adding magnetic particles to the zeolite framework also increased the stability of the composite structure.Adsorption kinetics and isotherm studies also found that the system follows the pseudo-second-order and Langmuir isotherm models.
基金supported by the National Natural Science Foundation of China(32172279,31871831)Shenyang Science and Technology Innovation Platform Project(21-103-0-14,21-104-0-28)Shenyang City Youth Science and Technology Innovation Leading Talent Project(RC200495).
文摘Commercial sterility does not guarantee the sustained stability of ultrahigh temperature(UHT)milk over 6 months shelf life.We explore the microbiota presented in normal(SZ)and quality deteriorated UHT milk(QY and WY)products from the same brand.Based on high-throughput sequencing research results,11 phyla and 54 genera were identified as dominant microbiota.Pseudomonas,Streptococcus,and Acinetobacter as core functional microbiota significantly influenced the UHT milk quality properties.Moreover,principal component analysis(PCA)and multivariate analyses were used to examine the quality characteristics,including 11 physicochemical parameters,10 fatty acids,and 2 enzyme activities,in normal and quality deteriorated UHT milk.We found that the abundance of Pseudomonas increased in quality deteriorated milk(WY)and showed a significant positive correlation with heat-resistant protease content.Acinetobacter in quality deteriorated milk(QY)also considerably contributed to the content of heat-resistant lipase,which resulted in spoilage deterioration of UHT milk.
文摘The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate.
文摘BACKGROUND The overlap of imaging manifestations among distinct splenic lesions gives rise to a diagnostic dilemma.Consequently,a definitive diagnosis primarily relies on his-tological results.The ultrasound(US)-guided coaxial core needle biopsy(CNB)not only procures sufficient tissue to help clarify the diagnosis,but reduces the incidence of puncture-related complications.CASE SUMMARY A 41-year-old female,with a history of pulmonary tuberculosis,was admitted to our hospital with multiple indeterminate splenic lesions.Gray-scale ultrasono-graphy demonstrated splenomegaly with numerous well-defined hypoechoic ma-sses.Abdominal contrast-enhanced computed tomography(CT)showed an en-larged spleen with multiple irregular-shaped,peripherally enhancing,hypodense lesions.Positron emission CT revealed numerous abnormal hyperglycemia foci.These imaging findings strongly indicated the possibility of infectious disease as the primary concern,with neoplastic lesions requiring exclusion.To obtain the precise pathological diagnosis,the US-guided coaxial CNB of the spleen was ca-rried out.The patient did not express any discomfort during the procedure.CONCLUSION Percutaneous US-guided coaxial CNB is an excellent and safe option for obtaining precise splenic tissue samples,as it significantly enhances sample yield for exact pathological analysis with minimum trauma to the spleen parenchyma and sur-rounding tissue.
基金supported by Educational Science Research Project of Beijing Union University“A Study on the Cultivation Path of Core Competencies of English Talents in Universities Under the Background of New Liberal Arts”(JK202209).
文摘The core competencies of college students can influence their further learning,employment,and personal development.This paper explores college English teaching from the three aspects of core competencies:cultural foundation,self-development,and social participation.Adapting to the challenges posed by the new era for the cultivation of foreign language talents,the paper aims to improve students’cultural literacy,independent learning,the ability of problem discovery and problem solving,and critical cultural thinking,so as to make them more competitive in employment and entrepreneurship.
文摘The main purpose of this paper is to investigate the effect of core eccentricity on the structural behavior of concrete tall buildings.Concrete buildings of 55 floors with plan dimensions 48.0×48.0 m2 were investigated.Three cases of main core locations are studied:centric(A),eccentric by one sixth(B)and one third(C)of building width.The three-dimensional finite element method has been used in conducting structural analysis through ETABS software.Gravity and lateral(wind and seismic)loadings are applied to all building cases.It has been concluded that the core location is the prime parameter governing the structural behavior of tall buildings.Although the first two cases(A,B)have acceptable and similar structural behaviors conforming to code limits,in the third case(C),the building behavior came beyond code limits.The author introduced remedial action by adding two secondary cores in the opposite direction of the main core(C-R)to restore the building behavior to the code limits.The results of this action were satisfactory.
文摘The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(GRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are investigated.The current study aims to carry out a dynamic analysis on the sandwich beam when the impactor hits the top face sheet with an initial velocity.For the layer analysis,the high-order shear deformation theory(HSDT)and Frostig's second model for the displacement fields of the core layer are used.The classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of time.In order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the LVI.Finite element(FE)simulations are conducted by means of the ABAQUS software.The effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed.
基金Shenzhen Institute of Information Technology,2022 University-Level Doctoral and Master Research Support Project(The First Batch)“Research on the Status and Countermeasures of Youth Identification on Socialist Core Values from the Perspective of Guangdong-Hong Kong-Macao Greater Bay Area”(SZIIT2022SK037)。
文摘Socialist core values are the concentrated expression and highly condensed values of the state,society,and individuals.They are also the embodiment of the values and spiritual consensus and pursuit in the life of the state and society.This article analyzes and summarizes the research results on the identification of socialist core values in China in recent years,mainly sorting out aspects such as the significance of identification,the dialectical relationship between identification and practice,differences in identification levels among different groups,and paths to enhance identification.Finally,suggestions for further deepening future research are proposed.
基金CPC Anhui Provincial Committee Education Working Committee Anhui Provincial Department of Education 2023 Comprehensive Reform and Ideological and Political Ability Enhancement Program of Colleges and Universities“Three-Whole Parenting”Project“The Dilemma and Optimization Path Research of‘Circularization’of Ideological and Political Education in Colleges and Universities”(sztsjh-2023-6-19)。
文摘Vocational undergraduate education has evolved from its initial stages to a full-scale implementation,achieving historic milestones along the way.However,its appeal still lags significantly behind that of general education.The development of students’core competencies in vocational undergraduate education faces several challenges,including the need for improvements in top-level design,a stronger focus on connotation development,and an upgraded linkage mechanism.To address these issues,it is suggested to refine the top-level design,enhance internal motivation,and build a robust vocational education ecosystem.
基金supported by the undergraduate scientific research and innovation project of Capital Medical University (No.XSKY2020078).
文摘Background:The Internet plus nursing service program is being piloted in China,which has become a new home nursing service model led by nurses.To enable safe and effective homecare service delivery,nurses working in the program need a high level of competency.However,the content of these core competencies and the training needs of nurses for Internet plus nursing services are still unknown.Aim:To describe nurses’perceptions of core competencies and training needs to work in the Internet plus nursing service program,thereby providing a reference for the development of training programs.Methods:A qualitative descriptive study using semi-structured interviews was conducted on 15 nurses with experience of working in the Internet plus nursing service program.Interviews were audio-recorded and transcribed verbatim,and the data were analyzed using thematic analysis.Results:Core competencies involved comprehensive assessment competence,direct care practice competence,health education and consulting competence,risk estimation and response competence,and communication competence.Training needs involved complex operational items,knowledge of chronic disease management,professional communication,risk identification and response,nursing standards,norms,and procedures,and utilization of information technology.Conclusions:The training system may be developed based on nurses’core competencies and their training needs to promote professional development of the Internet plus nursing service.
文摘The breakthrough of key core technology is a theoretical and practical strategic issue to realize the rise of the country.This paper analyzes the concept of key core technology and its breakthrough and analyzes its characteristics.Based on the perspective of participants,this paper summarizes the influencing factors of key core technology breakthroughs in enterprises:internal and external enterprises,universities and scientific research institutions,and government.This paper expands the relevant research on key core technology breakthroughs and provides inspiration for enterprises to carry out key core technology research and breakthrough practices.
基金supported by National Natural Science Foundation of China(Nos.11505013 and 11875090)Beijing Municipal Natural Science Foundation(No.1192008)Beijing Municipal Commission of Education(Nos.KM202010015003,22150122029,and 202210015017)。
文摘The effect of neutral pressure on the blue core in Ar helicon plasma under an inhomogeneous magnetic field was investigated in this work.The neutral pressure was set to 0.08 Pa,0.36 Pa,and 0.68 Pa.A Nikon camera,intensified charge-coupled device(ICCD),optical emission spectrometer(OES),and Langmuir probe were used to diagnose the blue core in helicon plasma.Helicon plasma discharges experienced density jumps from the E mode,H mode to W mode before power just rose to 200 W.The plasma density increased and maintained a central peak with the increase of neutral pressure.However,the brightness of the blue core gradually decreased.It is demonstrated that the relative intensity of Ar II spectral lines and the ionization rate in the central area were reduced.Radial electron temperature profiles were flattened and became hollow as neutral pressure increased.It is demonstrated that increasing the neutral pressure weakened the central heating efficiency dominated by the helicon wave and strengthened the edge heating efficiency governed by the TG wave and skin effect.Therefore,the present experiment successfully reveals how the neutral pressure affects the heating mechanism of helicon plasma in an inhomogeneous magnetic field.
基金supported by the Shanxi Provincial Foundation for Returned Overseas Scholars (No. 20220037)Natural Science Foundation of Shanxi Province (No. 20210302123085)Discipline Construction Project of Yuncheng University
文摘In this work,we perform a Bayesian inference of the crust-core transition density ρ_(t) of neutron stars based on the neutron-star radius and neutron-skin thickness data using a thermodynamical method.Uniform and Gaussian distributions for the ρ_(t) prior were adopted in the Bayesian approach.It has a larger probability of having values higher than 0.1 fm^(−3) for ρ_(t) as the uniform prior and neutron-star radius data were used.This was found to be controlled by the curvature K_(sym) of the nuclear symmetry energy.This phenomenon did not occur if K_(sym) was not extremely negative,namely,K_(sym)>−200 MeV.The value ofρ_(t) obtained was 0.075_(−0.01)^(+0.005) fm^(−3) at a confidence level of 68%when both the neutron-star radius and neutron-skin thickness data were considered.Strong anti-correlations were observed between ρ_(t),slope L,and curvature of the nuclear symmetry energy.The dependence of the three L-K_(sym) correlations predicted in the literature on crust-core density and pressure was quantitatively investigated.The most probable value of 0.08 fm^(−3) for ρ_(t) was obtained from the L-K_(sym) relationship proposed by Holt et al.while larger values were preferred for the other two relationships.
文摘The rotation of the Earth's liquid core creates the Nearly Diurnal Free Wobble (NDFW). It is one of the problems of researching the Earth's liquid core for us to retrieve the parameters of the Earth's Free Core Nutation (FCN),from the Earth's liquid core resonance of gravity tide waves on the diurnal frequency band. Since 1987, some scientists in many different countries have come to calculate the parameters of FCN by using the observational data of gravity tide waves on the diumal frequency band. They basically followed the Stacking method, which needed five diurnal waves for the resolution. In this paper, authors introduced the Aky-Btk value method with clearly geometrical meaning as a new method, which only requires three very high signal-noise-ratio waves o1, K1 and P1 for the resolution. Authors chose the observational data of the three superconducting gravimeter stations respectively located in Cantley of Canada, Wuhan of China and Brussels of Belgium, to compute the parameters of FCN. It was the first time that the observational results of the parameters of FCN obtained from gravitational tide were in accord with the parameters of FCN gained from VLBI since 1987.
文摘The elasto-gravitational deformation response of the Earths solid parts to the perturbations of the pressure and gravity on the core-mantle boundary (CMB) and the solid inner core boundary (ICB), due to the dynamical behaviors of the fluid outer core (FOC), is discussed. The internal load Love numbers, which are formulized in a general form in this study, are employed to describe the Earths deformation. The preliminary reference Earth model (PREM) is used as an example to calculate the internal load Love numbers on the Earths surface, CMB and ICB, respectively. The characteristics of the Earths deformation variation with the depth and the perturbation periods on the boundaries of the FOC are also investigated. The numerical results indicate that the internal load Love numbers decrease quickly with the increasing degree of the spherical harmonics of the displacement and depend strongly on the perturbation frequencies, especially on the high frequencies. The results, obtained in this work, can be used to construct the boundary conditions for the core dynamics of the long-period oscillations of the Earths fluid outer core.
基金jointly supported by the National Key Research and Development Program of China under Grant No. 2017YFC1501601the National Natural Science Foundation of China under Grant Nos. 42175005 and 41875054
文摘In this study,the characteristics of azimuthally asymmetric equivalent potential temperature(θ_(e))distributions in the outer core of tropical cyclones(TCs)encountering weak and strong vertical wind shear are examined using a Lagrangian trajectory method.Evaporatively forced downdrafts in the outer rainbands can transport low-entropy air downward,resulting in the lowestθ_(e)in the downshear-left boundary layer.Quantitative estimations ofθ_(e)recovery indicate that air parcels,especially those originating from the downshear-left outer core,can gradually revive from a low entropy state through surface enthalpy fluxes as the parcels move cyclonically.As a result,the maximumθ_(e)is observed in the downshear-right quadrant of a highly sheared TC.The trajectory analyses also indicate that parcels that move upward in the outer rainbands and those that travel through the inner core due to shear make a dominant contribution to the midlevel enhancement ofθ_(e)in the downshear-left outer core.In particular,the former plays a leading role in suchθ_(e)enhancements,while the latter plays a secondary role.As a result,moist potential stability occurs in the middle-to-lower troposphere in the downshear-left outer core.
基金Joint Fund of Research and Development Program of Henan Province,Grant/Award Number:222301420002National Natural Science Foundation of China,Grant/Award Number:U21A2064Scientific and Technological Innovation Talents in Colleges and Universities in Henan Province,Grant/Award Number:22HASTIT001。
文摘Material composition and structural design are important factors influencing the electromagnetic wave(EMW)absorption performance of materials.To alleviate the impedance mismatch attributed to the high dielectric constant of Ti_(3)C_(2)T_(x)MXene,we have successfully synthesized core‐shell structured SiO_(2)@MXene@MoS_(2)nanospheres.This architecture,comprising SiO_(2)as the core,MXene as the intermediate layer,and MoS_(2)as the outer shell,is achieved through an electrostatic self‐assembly method combined with a hydrothermal process.This complex core‐shell structure not only provides a variety of loss mechanisms that effectively dissipate electromagnetic energy but also prevents self‐aggregation of MXene and MoS_(2)nanosheets.Notably,the synergistic combination of SiO_(2)and MoS_(2)with highly conductive MXene enables the suitable dielectric constant of the composites,ensuring optimal impedance matching.Therefore,the core‐shell structured SiO_(2)@MXene@MoS_(2)nanospheres exhibit excellent EMW absorption performance,featuring a remarkable minimum reflection loss(RL_(min))of−52.11 dB(2.4 mm).It is noteworthy that these nanospheres achieve an ultra‐wide effective absorption bandwidth(EAB)of 6.72 GHz.This work provides a novel approach for designing and synthesizing high‐performance EMW absorbers characterized by“wide bandwidth and strong reflection loss.”