As the goal of"low carbon"sustainable development becomes more salient,the corporations'environmental,social,and governance(ESG)practices are under higher visibility.How to promote the ESG performance of...As the goal of"low carbon"sustainable development becomes more salient,the corporations'environmental,social,and governance(ESG)practices are under higher visibility.How to promote the ESG performance of corporations has become a big challenge that needs to be solved.Spatial econometrics methods based on panel data on listed corporations in the period from 2018 to 2023 are used in the paper to empirically analyze the peer effect of a corporation from the view of strategic interaction.The results found relatively positive industry peer effects as well as regional peer effects.However,the latter is much weaker.Industry-wise results indicate that most sectors demonstrate positive peer competition on ESG issues,with only a few,like the special equipment manufacturing industry,not showing significant peer effects.The empirical results in this paper support the mode of cooperative interaction among firms,help broaden the scope of understanding factors that encourage ESG practices,and suggest relevant policies for boosting corporate social responsibilities and sustainable development through encouraging factors.展开更多
Quadruped robots which have flexibility and load-bearing capacity,are regarded as the best mobile platform for remote operation in unstructured and restricted environments.In the process of remote operation of quadrup...Quadruped robots which have flexibility and load-bearing capacity,are regarded as the best mobile platform for remote operation in unstructured and restricted environments.In the process of remote operation of quadruped robots,their status is inevitably influenced by complex environments.To monitor the robot's real-time operation status and make necessary adjustments,this paper focuses on the single-leg of a quadruped robot,proposes a single-leg virtual-real interaction system based on Digital Twin,and studies its virtual-real interaction characteristics.The virtual-reality interaction system contains single-leg physical entity,single-leg virtual model,control system,data service system and communication system,enabling interactive applications for single-leg visual state monitoring and real-time control optimization.This paper creates a high-fidelity model based on the physical entity;provides a system performance analysis method based on the system framework;analyzes virtual-real interaction delay based on communication scheme;conducts stand and jump test based on the single-leg mathematical model and analyzes the interaction characteristics under position/force control.This system provides new insights for real-time monitoring and control optimization of quadruped robots.展开更多
Due to the weak interlayer interactions,the binary Ⅲ-Ⅵ chalcogenides Ga Se can exist in several distinct polymorphs.Among them,the so-called β-and ε-phases simultaneously exhibit favorable total energies and moder...Due to the weak interlayer interactions,the binary Ⅲ-Ⅵ chalcogenides Ga Se can exist in several distinct polymorphs.Among them,the so-called β-and ε-phases simultaneously exhibit favorable total energies and moderate band gaps,which offer a good platform to explore their thermoelectric properties.Here,we demonstrate by first-principles calculations that the two systems have very similar band structures and phonon dispersions,despite different stacking sequences between adjacent layers.Interestingly,the lattice thermal conductivity of ε-GaSe is obviously lower than that of β-GaSe,which is inherently tied to stronger lattice anharmonicity caused by bonding heterogeneity.Besides,both systems exhibit higher p-type power factors due to doubly degenerate bands with weaker dispersions around the valence band maximum.As a consequence,a significantly enhanced p-type figure-of-merit of 2.1 can be realized at 700 K along the out-of-plane direction of theε-phase.展开更多
This study aims to assess the comprehensive strengthening effect of a steel-ultra high performance concrete(UHPC)composite strengthening method.The axial force-moment interaction curve(N-M curve)was calculated in a no...This study aims to assess the comprehensive strengthening effect of a steel-ultra high performance concrete(UHPC)composite strengthening method.The axial force-moment interaction curve(N-M curve)was calculated in a novel way,using cross-sectional strains at ultimate states as well as real-time stress measurements for each material.The enclosed area of the N-M curve was defined as a comprehensive performance index for the system.We validate our approach with comparisons to numerical modeling and full-scale four-point bending experiments.Additionally,strengthening effects were compared for different sagging and hogging moments based on material stress responses,and the impact of various strengthening parameters was analyzed.We find that the N-M curve of the strengthened cross-section envelops that of the un-strengthened cross-section.Notably,improvements in flexural capacity are greater under sagging moments during the large eccentric failure stage,and greater under hogging moments during the small eccentric failure stage.This discrepancy is attributed to the strength utilization of strengthening materials.These findings provide a reference for understanding the strengthening effects and parameters of steel-UHPC composite.展开更多
The weak interlayer van der Waals(vdW) interactions in two-dimensional(2D) vdW materials enable sliding ferroelectricity as an effective strategy for modulating their intrinsic properties. In this work, we systematica...The weak interlayer van der Waals(vdW) interactions in two-dimensional(2D) vdW materials enable sliding ferroelectricity as an effective strategy for modulating their intrinsic properties. In this work, we systematically investigate the influence of interlayer sliding on the electronic behavior of PtSe_(2) using density functional theory(DFT) calculations. Our results demonstrate that interlayer sliding induces a pronounced photocurrent spanning the short-wavelength infrared to visible spectral ranges. Remarkably, under an applied gate voltage, the sliding ferroelectric PtSe_(2) exhibits anomalously enhanced photovoltaic performance and an ultrahigh extinction ratio.Transmission spectral analysis reveals that this phenomenon originates from band structure modifications driven by energy-level transitions. Furthermore, the observed photocurrent enhancement via sliding ferroelectricity demonstrates universality across diverse platinum-based optoelectronic devices. This study introduces a novel paradigm for tailoring the intrinsic characteristics of 2D vdW semiconductors, expanding the design space for next-generation ferroelectric materials in advanced optoelectronic applications.展开更多
The centrifugal pump is a prevalent power equipment widely used in different engineering patterns,and the impeller blade wrap angle significantly impacts its performance.A numerical investigation was conducted to anal...The centrifugal pump is a prevalent power equipment widely used in different engineering patterns,and the impeller blade wrap angle significantly impacts its performance.A numerical investigation was conducted to analyze the influence of the blade wrap angle on flow characteristics and energy distribution of a centrifugal pump evaluated as a low specific speed with a value of 69.This study investigates six impellermodels that possess varying blade wrap angles(95°,105°,115°,125°,135°,and 145°)that were created while maintaining the same volute and other geometrical characteristics.The investigation of energy loss was conducted to evaluate the values of total and entropy generation rates(TEG,EGR).The fluid-structure interaction was considered numerically using the software tools ANSYS Fluent and ANSYSWorkbench.The elastic structural dynamic equation was used to estimate the structural response,while the shear stress transport k–ωturbulence model was utilized for the fluid domain modeling.The findings suggest that the blade wrap angle has a significant influence on the efficiency of the pump.The impeller featuring a blade wrap angle of 145°exhibits higher efficiency,with a notable increase of 3.76%relative to the original model.Variations in the blade wrap angle impact the energy loss,shaft power,and pump head.The model with a 145°angle exhibited a maximum equivalent stress of 14.8MPa and a total deformation of 0.084 mm.The results provide valuable insights into the intricate flow mechanism of the centrifugal pump,particularly when considering various blade wrap angles.展开更多
Under the principal-agent relationship, there are two major factors that directly affect subsidiary strategy’s implementation and performance—enterprise groups’ internal interactive control and subsidiary managers...Under the principal-agent relationship, there are two major factors that directly affect subsidiary strategy’s implementation and performance—enterprise groups’ internal interactive control and subsidiary managers’ strategic behavior. Prior research showed that the parent companies hope their subsidiary managers to be obedient and active, i.e. to keep a high degree of strategic identity and subsidiary initiative. We build and analyze a model to test the mediating role of strategic identity and subsidiary initiative based on data collected from Chinese groups. The results show that interactive control, strategic identity and subsidiary initiative all could improve subsidiary performance, furthermore, subsidiary initiative is a mediator between decision-making decentralization and subsidiary performance, and also a mediator between horizontal communication and subsidiary performance, the mediating role of strategic identity is not tested, but vertical communication can improve strategic identity. In the conclusions, we provide guidance on how parent companies to choose excellent subsidiary managers, and then how to develop a suite interactive control system.展开更多
Multirotor has been applied to many military and civilian mission scenarios. From the perspective of reliability, it is difficult to ensure that multirotors do not generate hardware and software failures or performanc...Multirotor has been applied to many military and civilian mission scenarios. From the perspective of reliability, it is difficult to ensure that multirotors do not generate hardware and software failures or performance anomalies during the flight process. These failures and anomalies may result in mission interruptions, crashes, and even threats to the lives and property of human beings.Thus, the study of flight reliability problems of multirotors is conductive to the development of the drone industry and has theoretical significance and engineering value. This paper proposes a reliable flight performance assessment method of multirotors based on an Interacting Multiple Model Particle Filter(IMMPF) algorithm and health degree as the performance indicator. First, the multirotor is modeled by the Stochastic Hybrid System(SHS) model, and the problem of reliable flight performance assessment is formulated. In order to solve the problem, the IMMPF algorithm is presented to estimate the real-time probability distribution of hybrid state of the established SHS-based multirotor model, since it can decrease estimation errors compared with the standard interacting multiple model algorithm based on extended Kalman filter. Then, the reliable flight performance is assessed with health degree based on the estimation result. Finally, a case study of a multirotor suffering from sensor anomalies is presented to validate the effectiveness of the proposed method.展开更多
The inflation of a five-ring cone parachute with the airflow velocity of 18 m/s is studied based on the simplified arbitrary Lagrange Euler （SALE）/fluid-structure interaction （FSI） method. The numerical results of...The inflation of a five-ring cone parachute with the airflow velocity of 18 m/s is studied based on the simplified arbitrary Lagrange Euler （SALE）/fluid-structure interaction （FSI） method. The numerical results of the canopy shape, stability, opening load, and drag area are obtained, and they are well consistent with the experimental data gained from wind tunnel tests. The method is then used to simulate the opening process under different velocities. It is found that the first load shock affected by the velocity often occurs at the end of the initial inflation stage. For the first time, the phenomena that the inflation distance proportion coefficient increases and the dynamic load coefficient decreases, respectively, with the increase in the velocity are revealed. The above proposed method is competent to solve the large deformation problem without empirial coefficients, and can collect more space-time details of fluid-structure-motion information when it is compared with the traditional method.展开更多
Intermolecular interactions and properties of TNT（2,4,6-trinitrotoluene）/CL-20（2,4,6,8,10,12-hexanitrohexaazaisowurtzitane） cocrystal were studied by density functional theory（DFT） methods. Binding energy, natur...Intermolecular interactions and properties of TNT（2,4,6-trinitrotoluene）/CL-20（2,4,6,8,10,12-hexanitrohexaazaisowurtzitane） cocrystal were studied by density functional theory（DFT） methods. Binding energy, natural bond orbital（NBO）, and atom in molecules（AIM） analysis were performed to investigate the intermolecular interactions in the cocrystal. Results show that the unconventional CH···O type hydrogen bond plays a key role in forming the cocrystal. The variation tendency of entropy and enthalpy shows that the formation of the cocrystal is an exothermic process and low temperature will be benefit for the assembling of complexes. The calculated detonation velocity of the cocrystal agrees well with the experimental value which is higher than that of the physical mixture of TNT and CL-20. In addition, bond dissociation energies（BDEs） of the weakest trigger bond in TNT/CL-20 complex were calculated and the results show that the TNT/CL-20 complex is thermally stable. Finally, first-principles calculations were performed and analysis of the nitro group Mulliken charge indicates that the cocrystal is less sensitive than pure CL-20.展开更多
Metal-organic frameworks(MOFs) have showed high promise in CO_(2)-electroreduction, yet their generally insufficient conductivity or low electron-transfer efficiency have largely restricted the wide-spread application...Metal-organic frameworks(MOFs) have showed high promise in CO_(2)-electroreduction, yet their generally insufficient conductivity or low electron-transfer efficiency have largely restricted the wide-spread applications. Herein, fullerene molecules(i.e., C60and C70) have been successfully introduced into the pore-channels of a Co-porphyrin based MOF through a facile strategy. Thus-obtained hybrid materials present higher electron-transfer ability, enhanced CO_(2)adsorption-enthalpy and CO_(2)electroreduction activity. Notably, the charge transfer resistance(Rct) of C60@MOF-545-Co is almost 5 times lower of than that of MOF-545-Co, as well as 1.5 times increased for the CO_(2)adsorption enthalpy. As expect, the FECO of C60@MOF-545-Co(97.0%) is largely higher than MOF-545-Co(70.2%), C60@MOF-545(19.4%), C60(11.5%)and physical mixture(70.3%) and presented as one of the best CO_(2)electroreduction catalysts reported in H-cell system. The facile strategy would give rise to new insight into the exploration of powerful MOFbased hybrid materials in high-efficiency CO_(2)electroreduction.展开更多
Based on the different hydrophobicities of the intermediates of proteins the various conformational intermediates of the refolding of a-amylase originally denatured with 8.0 mol/L urea solution were separated with hi...Based on the different hydrophobicities of the intermediates of proteins the various conformational intermediates of the refolding of a-amylase originally denatured with 8.0 mol/L urea solution were separated with high performance hydrophobic interaction chromatography(HPHIC). Compared to the separation of the same intermediates with weak anion exchange chromatography and size-exclusion chromatography the result obtained with HPHIC is the best It would be expected that HPHIC may be a strongly potential tool to separate intermediates of some proteins which cannot be, or cannot completely be refolded by HPHIC.展开更多
To offer a theoretic guidance to practice, on the basis of the work in an emerging strand of supply chain management and by matching the constructs of performance and risk together, a framework between supply chain ri...To offer a theoretic guidance to practice, on the basis of the work in an emerging strand of supply chain management and by matching the constructs of performance and risk together, a framework between supply chain risk management and organizational performance is developed. The framework includes a series of mutually associated processes as follows: risk sources and profiles, risk and performance drives, risk and performance consequences, risk management responses, and risk and performance outcomes. Furthermore, every process is elaborated on in detail. Thereinto, organizational performance consists of efficiency and effectiveness which is linked to risk drivers and risk management responses. Finally, some necessary discussions and supplements are put forward from a practical point of view. This study is to some extent expected to be conducive to the theories and the practice of supply chain management for contemporary enterprises.展开更多
A rapid, fast and precise method has been developed and validated for the simultaneous determination of amlodipine with H1-receptor antagonists (cetirizine, fexofenadine, and buclizine) from dosage forms. The chromato...A rapid, fast and precise method has been developed and validated for the simultaneous determination of amlodipine with H1-receptor antagonists (cetirizine, fexofenadine, and buclizine) from dosage forms. The chromatography was performed on a Purospher? Star, C18 (5 mm, 250 × 4.6 mm) column using acetonitrile: buffer (0.01 mM) (40:60, v/v, pH adjusted to 3.0), as a mobile phase. The mobile phase was pumped at a flow rate of 1.0 mL·min-1 and UV detection was performed at 240 nm. The method was validated for linearity, accuracy, precision and specificity. The method was applied to study the interaction between amlodipine and H1-receptor antagonists. These interactions were carried out in simulated gastric juice (pH 1), simulated full stomach (pH 4), blood pH (pH 7.4) and simulating GI (pH 9). The interacting drugs were heated at 37℃ with intermit-tent shaking and the samples were withdrawn every thirty minutes for three hours and drug contents were analyzed by RP-HPLC techniques. In most cases the in vitro availability of amlodipine was decreased. It was observed that the change in in vitro availability was pH dependent.展开更多
Corporations actively fulfilling corporate social responsibility(CSR)is of more significance to society's sustainable development nowadays.This research discusses the interaction between CSR and corporate performa...Corporations actively fulfilling corporate social responsibility(CSR)is of more significance to society's sustainable development nowadays.This research discusses the interaction between CSR and corporate performance and then adopts other mediation variables to explain the underlying mechanism.The empirical analyses are performed on a sample of 201 listed Chinese firms.The result shows that CSR has a weak negative impact on corporate perfbnnance while being positively influenced by corporate performance significantly.Further study finds the reason may be CSR requires financial support,but has little to do with increasing shareholder wealth.展开更多
In order to improve the prediction precision of the safety performance function （SPF） of freeway basic segments, design and crash data of 640 segments are collected from different institutions. Three negative binomi...In order to improve the prediction precision of the safety performance function （SPF） of freeway basic segments, design and crash data of 640 segments are collected from different institutions. Three negative binomial （NB） regression models and three generalized negative binomial （GNB） regression models are built to prove that the interactive influence of explanatory variables plays an important role in fitting goodness. The effective use of the GNB model in analyzing the interactive influence of explanatory variables and predicting freeway basic segments is demonstrated. Among six models, the two models （one is the NB model and the other is the GNB model. ） which consider the interactive influence of the annual average daily traffic （AADT） and length are more reasonable for predicting results. Furthermore, a comprehensive study is carried out to prove that when considering the interactive influence, the NB and GNB models have almost the same fitting performance in estimating the crashes, among which the GNB model is slightly better for prediction performance.展开更多
In this study, two-dimensional MXene (Ti3 C2 Tx ) was employed to modify the interface of carbon fiber-reinforced polyetherketoneketone (CF/PEKK) composites, in order to simultaneously improve the electromagnetic inte...In this study, two-dimensional MXene (Ti3 C2 Tx ) was employed to modify the interface of carbon fiber-reinforced polyetherketoneketone (CF/PEKK) composites, in order to simultaneously improve the electromagnetic interference (EMI) shielding performances and mechanical properties. The obtained CF/PEKK composites possessed outstanding EMI and mechanical performances, as anticipated. Specifically, the CF/PEKK composites modified with MXene at 1 mg mL–1 exhibited an excellent EMI shielding effectiveness of 65.2 dB in the X-band, a 103.1% enhancement compared with the unmodified CF/PEKK composites. The attractive EMI shielding performances of CF/PEKK composites originated from enhanced ohmic losses and multiple reflections of electromagnetic waves with the help of the MXene and CF layers. In addition, CF/PEKK composites achieved the best mechanical properties by optimizing the dispersion concentration of MXene to 0.1 mg mL–1 . The flexural strength, flexural modulus, and interlaminar shear strength of CF/PEKK composites reached 1127 MPa, 81 GPa, and 89 MPa, which were 28.5%, 9.5%, and 29.7% higher than that of the unmodified CF/PEKK composites, respectively. Such improvement in mechanical properties could be ascribed to the comprehensive effect of mechanical interlocking, hydrogen bonds, and Van der Waals forces between the introduced MXene and CF, PEKK, respectively.展开更多
The helico-axial multiphase pump is often used for gas-liquid mixture transportation in offshore oilfields,and slug flow is the main reason for the unstable operation of the pump.Aimed for slug flow condition,a self-d...The helico-axial multiphase pump is often used for gas-liquid mixture transportation in offshore oilfields,and slug flow is the main reason for the unstable operation of the pump.Aimed for slug flow condition,a self-designed three-stage multiphase pump is set to the object to perform unsteady simulations and fluid-structure interaction calculations,and the inlet gas void fraction(IGVF)is set from 20%to 80%.The results show that affected by the flow from the slug,the gas-liquid two-phase flow pattern in the multiphase pump changes sharply,resulting in severe fluctuations in the differential pressure,spindle torque and deformation of the multiphase pump.The gas-phase enters the first-impeller along the suction blade surface when affected by Taylor bubbles,while the second and third-stage impellers gas-phases are in the form of small air masses flow into the impeller along the pressure blade surface.The deformation trend of impeller torque,differential pressure and the main pump spindle is similar to that of trigonometric function,while the fluctuation of torque is more intense,and the shape variable of spindle increases with the inflow of liquid plug,and the maximum deformation amount increases by10.9%at high GVF relative to IGVF.展开更多
Considering the information interaction in the virtual-real network,this paper introduces a novel three-layer model that explores the integrated influence between virtual and real networks.Existing models often fail t...Considering the information interaction in the virtual-real network,this paper introduces a novel three-layer model that explores the integrated influence between virtual and real networks.Existing models often fail to capture the dynamic feedback between these networks and do not effectively simulate integrated decision-making processes.Focusing on the Facility Service Balance Problem,we aim to optimize resource allocation and information diffusion in response to real-world events like natural disasters or large-scale activities.Based on the Linear Threshold model,the Feedback Linear Threshold model,which incorporates feedback mechanisms between virtual and real networks and integrates both original and feedback information in the activation function of nodes,has been proposed to better simulate the information feedback and integrated decision-making process.Then,combined with location-based interpersonal and online social networks,a comprehensive framework that models decision-making processes without direct influence between decision-makers has been provided,focusing on the decision-making of individuals influenced by cumulative information,ultimately maximizing the facility service efficiency.Finally,conduct experiments have been conducted,using two types of data to test the general effectiveness of the feedback mechanism.展开更多
To study the effect of guide vane outlet angle on pump performance and impeller radial force in an axial-flow heart pump, guide vane outlet angle/34 is considered to be 20°, 15°, 10°, 5° and 3°...To study the effect of guide vane outlet angle on pump performance and impeller radial force in an axial-flow heart pump, guide vane outlet angle/34 is considered to be 20°, 15°, 10°, 5° and 3° respectively. Based on ANSYS Fluent, numerical results of pump head and efficiency are validated by exper/ment results, in which Xanthan gum solutions are used with concentration of 0.06 wt. % as working fluid. Then, the effects of/34 on pump performance and impeller radial force are discussed, the errors of head and efficiency between test and simulation are within 5%. The results a/so indicate that the pump performance and efficiency are much better than those of other angles when guide vane outlet angle/34 is 10°, and the maximum variations in head and efficiency are 1.9% and 2.2%, respectively. With/34 increasing, the pulsation of radial force decreases firstly and then increases, when/34 is 10°, the minimum pulsation is 0. 0392N, which is about 80% of the maximum pulsation amplitude.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.72073045).
文摘As the goal of"low carbon"sustainable development becomes more salient,the corporations'environmental,social,and governance(ESG)practices are under higher visibility.How to promote the ESG performance of corporations has become a big challenge that needs to be solved.Spatial econometrics methods based on panel data on listed corporations in the period from 2018 to 2023 are used in the paper to empirically analyze the peer effect of a corporation from the view of strategic interaction.The results found relatively positive industry peer effects as well as regional peer effects.However,the latter is much weaker.Industry-wise results indicate that most sectors demonstrate positive peer competition on ESG issues,with only a few,like the special equipment manufacturing industry,not showing significant peer effects.The empirical results in this paper support the mode of cooperative interaction among firms,help broaden the scope of understanding factors that encourage ESG practices,and suggest relevant policies for boosting corporate social responsibilities and sustainable development through encouraging factors.
文摘Quadruped robots which have flexibility and load-bearing capacity,are regarded as the best mobile platform for remote operation in unstructured and restricted environments.In the process of remote operation of quadruped robots,their status is inevitably influenced by complex environments.To monitor the robot's real-time operation status and make necessary adjustments,this paper focuses on the single-leg of a quadruped robot,proposes a single-leg virtual-real interaction system based on Digital Twin,and studies its virtual-real interaction characteristics.The virtual-reality interaction system contains single-leg physical entity,single-leg virtual model,control system,data service system and communication system,enabling interactive applications for single-leg visual state monitoring and real-time control optimization.This paper creates a high-fidelity model based on the physical entity;provides a system performance analysis method based on the system framework;analyzes virtual-real interaction delay based on communication scheme;conducts stand and jump test based on the single-leg mathematical model and analyzes the interaction characteristics under position/force control.This system provides new insights for real-time monitoring and control optimization of quadruped robots.
基金supported by the National Natural Science Foundation of China(Grant Nos.62074114 and 12474019)。
文摘Due to the weak interlayer interactions,the binary Ⅲ-Ⅵ chalcogenides Ga Se can exist in several distinct polymorphs.Among them,the so-called β-and ε-phases simultaneously exhibit favorable total energies and moderate band gaps,which offer a good platform to explore their thermoelectric properties.Here,we demonstrate by first-principles calculations that the two systems have very similar band structures and phonon dispersions,despite different stacking sequences between adjacent layers.Interestingly,the lattice thermal conductivity of ε-GaSe is obviously lower than that of β-GaSe,which is inherently tied to stronger lattice anharmonicity caused by bonding heterogeneity.Besides,both systems exhibit higher p-type power factors due to doubly degenerate bands with weaker dispersions around the valence band maximum.As a consequence,a significantly enhanced p-type figure-of-merit of 2.1 can be realized at 700 K along the out-of-plane direction of theε-phase.
基金supported by the National Natural Science Foundation of China(Nos.51938005,52090082,and 52378395)the National Key Research and Development Program of China(No.2023YFB2604402).
文摘This study aims to assess the comprehensive strengthening effect of a steel-ultra high performance concrete(UHPC)composite strengthening method.The axial force-moment interaction curve(N-M curve)was calculated in a novel way,using cross-sectional strains at ultimate states as well as real-time stress measurements for each material.The enclosed area of the N-M curve was defined as a comprehensive performance index for the system.We validate our approach with comparisons to numerical modeling and full-scale four-point bending experiments.Additionally,strengthening effects were compared for different sagging and hogging moments based on material stress responses,and the impact of various strengthening parameters was analyzed.We find that the N-M curve of the strengthened cross-section envelops that of the un-strengthened cross-section.Notably,improvements in flexural capacity are greater under sagging moments during the large eccentric failure stage,and greater under hogging moments during the small eccentric failure stage.This discrepancy is attributed to the strength utilization of strengthening materials.These findings provide a reference for understanding the strengthening effects and parameters of steel-UHPC composite.
基金supported by the National Key Research and Development Program of China (Grant No. 2024YFB3211701)the National Natural Science Foundation of China (Grant Nos. T2222011, 62174026, and 12274234)+1 种基金the National Key Research and Development Program of China (Grant Nos. 2023YFB3611400 and 2019YFA0308000)the Fundamental Research Funds for the Central Universities (Grant No. 242023k30027)。
文摘The weak interlayer van der Waals(vdW) interactions in two-dimensional(2D) vdW materials enable sliding ferroelectricity as an effective strategy for modulating their intrinsic properties. In this work, we systematically investigate the influence of interlayer sliding on the electronic behavior of PtSe_(2) using density functional theory(DFT) calculations. Our results demonstrate that interlayer sliding induces a pronounced photocurrent spanning the short-wavelength infrared to visible spectral ranges. Remarkably, under an applied gate voltage, the sliding ferroelectric PtSe_(2) exhibits anomalously enhanced photovoltaic performance and an ultrahigh extinction ratio.Transmission spectral analysis reveals that this phenomenon originates from band structure modifications driven by energy-level transitions. Furthermore, the observed photocurrent enhancement via sliding ferroelectricity demonstrates universality across diverse platinum-based optoelectronic devices. This study introduces a novel paradigm for tailoring the intrinsic characteristics of 2D vdW semiconductors, expanding the design space for next-generation ferroelectric materials in advanced optoelectronic applications.
文摘The centrifugal pump is a prevalent power equipment widely used in different engineering patterns,and the impeller blade wrap angle significantly impacts its performance.A numerical investigation was conducted to analyze the influence of the blade wrap angle on flow characteristics and energy distribution of a centrifugal pump evaluated as a low specific speed with a value of 69.This study investigates six impellermodels that possess varying blade wrap angles(95°,105°,115°,125°,135°,and 145°)that were created while maintaining the same volute and other geometrical characteristics.The investigation of energy loss was conducted to evaluate the values of total and entropy generation rates(TEG,EGR).The fluid-structure interaction was considered numerically using the software tools ANSYS Fluent and ANSYSWorkbench.The elastic structural dynamic equation was used to estimate the structural response,while the shear stress transport k–ωturbulence model was utilized for the fluid domain modeling.The findings suggest that the blade wrap angle has a significant influence on the efficiency of the pump.The impeller featuring a blade wrap angle of 145°exhibits higher efficiency,with a notable increase of 3.76%relative to the original model.Variations in the blade wrap angle impact the energy loss,shaft power,and pump head.The model with a 145°angle exhibited a maximum equivalent stress of 14.8MPa and a total deformation of 0.084 mm.The results provide valuable insights into the intricate flow mechanism of the centrifugal pump,particularly when considering various blade wrap angles.
文摘Under the principal-agent relationship, there are two major factors that directly affect subsidiary strategy’s implementation and performance—enterprise groups’ internal interactive control and subsidiary managers’ strategic behavior. Prior research showed that the parent companies hope their subsidiary managers to be obedient and active, i.e. to keep a high degree of strategic identity and subsidiary initiative. We build and analyze a model to test the mediating role of strategic identity and subsidiary initiative based on data collected from Chinese groups. The results show that interactive control, strategic identity and subsidiary initiative all could improve subsidiary performance, furthermore, subsidiary initiative is a mediator between decision-making decentralization and subsidiary performance, and also a mediator between horizontal communication and subsidiary performance, the mediating role of strategic identity is not tested, but vertical communication can improve strategic identity. In the conclusions, we provide guidance on how parent companies to choose excellent subsidiary managers, and then how to develop a suite interactive control system.
基金co-supported by the Beijing Natural Science Foundation of China (No. 4194074)the National Key R&D Program of China (No. 2017YFC1600605)+1 种基金the Shandong Provincial Natural Science Foundation of China (No. ZR2018BF016)the Beijing Municipal Education Commission Research Program-General Project of China (No. KM201910011011)
文摘Multirotor has been applied to many military and civilian mission scenarios. From the perspective of reliability, it is difficult to ensure that multirotors do not generate hardware and software failures or performance anomalies during the flight process. These failures and anomalies may result in mission interruptions, crashes, and even threats to the lives and property of human beings.Thus, the study of flight reliability problems of multirotors is conductive to the development of the drone industry and has theoretical significance and engineering value. This paper proposes a reliable flight performance assessment method of multirotors based on an Interacting Multiple Model Particle Filter(IMMPF) algorithm and health degree as the performance indicator. First, the multirotor is modeled by the Stochastic Hybrid System(SHS) model, and the problem of reliable flight performance assessment is formulated. In order to solve the problem, the IMMPF algorithm is presented to estimate the real-time probability distribution of hybrid state of the established SHS-based multirotor model, since it can decrease estimation errors compared with the standard interacting multiple model algorithm based on extended Kalman filter. Then, the reliable flight performance is assessed with health degree based on the estimation result. Finally, a case study of a multirotor suffering from sensor anomalies is presented to validate the effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China(No.11172137)the Aeronautical Science Foundation of China(No.20122910001)
文摘The inflation of a five-ring cone parachute with the airflow velocity of 18 m/s is studied based on the simplified arbitrary Lagrange Euler （SALE）/fluid-structure interaction （FSI） method. The numerical results of the canopy shape, stability, opening load, and drag area are obtained, and they are well consistent with the experimental data gained from wind tunnel tests. The method is then used to simulate the opening process under different velocities. It is found that the first load shock affected by the velocity often occurs at the end of the initial inflation stage. For the first time, the phenomena that the inflation distance proportion coefficient increases and the dynamic load coefficient decreases, respectively, with the increase in the velocity are revealed. The above proposed method is competent to solve the large deformation problem without empirial coefficients, and can collect more space-time details of fluid-structure-motion information when it is compared with the traditional method.
文摘Intermolecular interactions and properties of TNT（2,4,6-trinitrotoluene）/CL-20（2,4,6,8,10,12-hexanitrohexaazaisowurtzitane） cocrystal were studied by density functional theory（DFT） methods. Binding energy, natural bond orbital（NBO）, and atom in molecules（AIM） analysis were performed to investigate the intermolecular interactions in the cocrystal. Results show that the unconventional CH···O type hydrogen bond plays a key role in forming the cocrystal. The variation tendency of entropy and enthalpy shows that the formation of the cocrystal is an exothermic process and low temperature will be benefit for the assembling of complexes. The calculated detonation velocity of the cocrystal agrees well with the experimental value which is higher than that of the physical mixture of TNT and CL-20. In addition, bond dissociation energies（BDEs） of the weakest trigger bond in TNT/CL-20 complex were calculated and the results show that the TNT/CL-20 complex is thermally stable. Finally, first-principles calculations were performed and analysis of the nitro group Mulliken charge indicates that the cocrystal is less sensitive than pure CL-20.
基金financially supported by the National Natural Science Foundation of China (Nos. 22171139 and 21901122)Natural Science Foundation of Educational Commission of Anhui Province of China (No. KJ2020A0240)+1 种基金the Natural Science Research of Jiangsu Higher Education Institutions of China (No.19KJB150011)Project funded by China Postdoctoral Science Foundation (No. 2019M651873)。
文摘Metal-organic frameworks(MOFs) have showed high promise in CO_(2)-electroreduction, yet their generally insufficient conductivity or low electron-transfer efficiency have largely restricted the wide-spread applications. Herein, fullerene molecules(i.e., C60and C70) have been successfully introduced into the pore-channels of a Co-porphyrin based MOF through a facile strategy. Thus-obtained hybrid materials present higher electron-transfer ability, enhanced CO_(2)adsorption-enthalpy and CO_(2)electroreduction activity. Notably, the charge transfer resistance(Rct) of C60@MOF-545-Co is almost 5 times lower of than that of MOF-545-Co, as well as 1.5 times increased for the CO_(2)adsorption enthalpy. As expect, the FECO of C60@MOF-545-Co(97.0%) is largely higher than MOF-545-Co(70.2%), C60@MOF-545(19.4%), C60(11.5%)and physical mixture(70.3%) and presented as one of the best CO_(2)electroreduction catalysts reported in H-cell system. The facile strategy would give rise to new insight into the exploration of powerful MOFbased hybrid materials in high-efficiency CO_(2)electroreduction.
文摘Based on the different hydrophobicities of the intermediates of proteins the various conformational intermediates of the refolding of a-amylase originally denatured with 8.0 mol/L urea solution were separated with high performance hydrophobic interaction chromatography(HPHIC). Compared to the separation of the same intermediates with weak anion exchange chromatography and size-exclusion chromatography the result obtained with HPHIC is the best It would be expected that HPHIC may be a strongly potential tool to separate intermediates of some proteins which cannot be, or cannot completely be refolded by HPHIC.
文摘To offer a theoretic guidance to practice, on the basis of the work in an emerging strand of supply chain management and by matching the constructs of performance and risk together, a framework between supply chain risk management and organizational performance is developed. The framework includes a series of mutually associated processes as follows: risk sources and profiles, risk and performance drives, risk and performance consequences, risk management responses, and risk and performance outcomes. Furthermore, every process is elaborated on in detail. Thereinto, organizational performance consists of efficiency and effectiveness which is linked to risk drivers and risk management responses. Finally, some necessary discussions and supplements are put forward from a practical point of view. This study is to some extent expected to be conducive to the theories and the practice of supply chain management for contemporary enterprises.
文摘A rapid, fast and precise method has been developed and validated for the simultaneous determination of amlodipine with H1-receptor antagonists (cetirizine, fexofenadine, and buclizine) from dosage forms. The chromatography was performed on a Purospher? Star, C18 (5 mm, 250 × 4.6 mm) column using acetonitrile: buffer (0.01 mM) (40:60, v/v, pH adjusted to 3.0), as a mobile phase. The mobile phase was pumped at a flow rate of 1.0 mL·min-1 and UV detection was performed at 240 nm. The method was validated for linearity, accuracy, precision and specificity. The method was applied to study the interaction between amlodipine and H1-receptor antagonists. These interactions were carried out in simulated gastric juice (pH 1), simulated full stomach (pH 4), blood pH (pH 7.4) and simulating GI (pH 9). The interacting drugs were heated at 37℃ with intermit-tent shaking and the samples were withdrawn every thirty minutes for three hours and drug contents were analyzed by RP-HPLC techniques. In most cases the in vitro availability of amlodipine was decreased. It was observed that the change in in vitro availability was pH dependent.
文摘Corporations actively fulfilling corporate social responsibility(CSR)is of more significance to society's sustainable development nowadays.This research discusses the interaction between CSR and corporate performance and then adopts other mediation variables to explain the underlying mechanism.The empirical analyses are performed on a sample of 201 listed Chinese firms.The result shows that CSR has a weak negative impact on corporate perfbnnance while being positively influenced by corporate performance significantly.Further study finds the reason may be CSR requires financial support,but has little to do with increasing shareholder wealth.
基金The National Natural Science Foundation of China(No.51408229,51278202)the Program of the Key Laboratory of Road and Traffic Engineering of the Ministry of Education,Tongji University(No.K201204)the Science and Technology Program of Guangdong Communication Department(No.2013-02-068)
文摘In order to improve the prediction precision of the safety performance function （SPF） of freeway basic segments, design and crash data of 640 segments are collected from different institutions. Three negative binomial （NB） regression models and three generalized negative binomial （GNB） regression models are built to prove that the interactive influence of explanatory variables plays an important role in fitting goodness. The effective use of the GNB model in analyzing the interactive influence of explanatory variables and predicting freeway basic segments is demonstrated. Among six models, the two models （one is the NB model and the other is the GNB model. ） which consider the interactive influence of the annual average daily traffic （AADT） and length are more reasonable for predicting results. Furthermore, a comprehensive study is carried out to prove that when considering the interactive influence, the NB and GNB models have almost the same fitting performance in estimating the crashes, among which the GNB model is slightly better for prediction performance.
基金supported by the Shanghai Science and Tech-nology Committee(No.22511102400)Prof.Zhang would like to appreciate the financial support from the Fundamental Research Funds for the Central Universities(No.2232020G-12)+1 种基金the Fund of National Engineering Research Center for Commercial Aircraft Manufacturing(No.COMAC-SFGS-2022-2376)the Textile Vi-sion Basic Research Program(No.J202105).
文摘In this study, two-dimensional MXene (Ti3 C2 Tx ) was employed to modify the interface of carbon fiber-reinforced polyetherketoneketone (CF/PEKK) composites, in order to simultaneously improve the electromagnetic interference (EMI) shielding performances and mechanical properties. The obtained CF/PEKK composites possessed outstanding EMI and mechanical performances, as anticipated. Specifically, the CF/PEKK composites modified with MXene at 1 mg mL–1 exhibited an excellent EMI shielding effectiveness of 65.2 dB in the X-band, a 103.1% enhancement compared with the unmodified CF/PEKK composites. The attractive EMI shielding performances of CF/PEKK composites originated from enhanced ohmic losses and multiple reflections of electromagnetic waves with the help of the MXene and CF layers. In addition, CF/PEKK composites achieved the best mechanical properties by optimizing the dispersion concentration of MXene to 0.1 mg mL–1 . The flexural strength, flexural modulus, and interlaminar shear strength of CF/PEKK composites reached 1127 MPa, 81 GPa, and 89 MPa, which were 28.5%, 9.5%, and 29.7% higher than that of the unmodified CF/PEKK composites, respectively. Such improvement in mechanical properties could be ascribed to the comprehensive effect of mechanical interlocking, hydrogen bonds, and Van der Waals forces between the introduced MXene and CF, PEKK, respectively.
基金the support of the National Key R&D Program of China(Grant No.2020YFB2010002)。
文摘The helico-axial multiphase pump is often used for gas-liquid mixture transportation in offshore oilfields,and slug flow is the main reason for the unstable operation of the pump.Aimed for slug flow condition,a self-designed three-stage multiphase pump is set to the object to perform unsteady simulations and fluid-structure interaction calculations,and the inlet gas void fraction(IGVF)is set from 20%to 80%.The results show that affected by the flow from the slug,the gas-liquid two-phase flow pattern in the multiphase pump changes sharply,resulting in severe fluctuations in the differential pressure,spindle torque and deformation of the multiphase pump.The gas-phase enters the first-impeller along the suction blade surface when affected by Taylor bubbles,while the second and third-stage impellers gas-phases are in the form of small air masses flow into the impeller along the pressure blade surface.The deformation trend of impeller torque,differential pressure and the main pump spindle is similar to that of trigonometric function,while the fluctuation of torque is more intense,and the shape variable of spindle increases with the inflow of liquid plug,and the maximum deformation amount increases by10.9%at high GVF relative to IGVF.
基金supported by the National Social Science Fund of China[grant numbers 24&ZD163].
文摘Considering the information interaction in the virtual-real network,this paper introduces a novel three-layer model that explores the integrated influence between virtual and real networks.Existing models often fail to capture the dynamic feedback between these networks and do not effectively simulate integrated decision-making processes.Focusing on the Facility Service Balance Problem,we aim to optimize resource allocation and information diffusion in response to real-world events like natural disasters or large-scale activities.Based on the Linear Threshold model,the Feedback Linear Threshold model,which incorporates feedback mechanisms between virtual and real networks and integrates both original and feedback information in the activation function of nodes,has been proposed to better simulate the information feedback and integrated decision-making process.Then,combined with location-based interpersonal and online social networks,a comprehensive framework that models decision-making processes without direct influence between decision-makers has been provided,focusing on the decision-making of individuals influenced by cumulative information,ultimately maximizing the facility service efficiency.Finally,conduct experiments have been conducted,using two types of data to test the general effectiveness of the feedback mechanism.
基金Supported by the National Natural Science Foundation of China(No.51574161)the Education Science Project of Young and Middle-aged Teachers of Universities in Fujian Province(No.JZ160396)
文摘To study the effect of guide vane outlet angle on pump performance and impeller radial force in an axial-flow heart pump, guide vane outlet angle/34 is considered to be 20°, 15°, 10°, 5° and 3° respectively. Based on ANSYS Fluent, numerical results of pump head and efficiency are validated by exper/ment results, in which Xanthan gum solutions are used with concentration of 0.06 wt. % as working fluid. Then, the effects of/34 on pump performance and impeller radial force are discussed, the errors of head and efficiency between test and simulation are within 5%. The results a/so indicate that the pump performance and efficiency are much better than those of other angles when guide vane outlet angle/34 is 10°, and the maximum variations in head and efficiency are 1.9% and 2.2%, respectively. With/34 increasing, the pulsation of radial force decreases firstly and then increases, when/34 is 10°, the minimum pulsation is 0. 0392N, which is about 80% of the maximum pulsation amplitude.
