We investigated a developed arm roll forwarder at Nasu in Tochigi Prefecture, Japan. An arm roll forwarder can only load a steel container that has been fully loaded with logs beforehand, and can later unload such a c...We investigated a developed arm roll forwarder at Nasu in Tochigi Prefecture, Japan. An arm roll forwarder can only load a steel container that has been fully loaded with logs beforehand, and can later unload such a container. Such a forwarder can shorten the loading and untoading times and improve operational efficiency. We examined two operation systems with an arm roll forwarder and a forwarder. In the first system the loading was done with a grapple-loader. In the second system the loading was done with a processor. The loading times of an arm roll forwarder were significantly tess than those of a forwarder. Because the optimal cycle times （excluding the waiting times for an arm roll for- warder） were significantly reduced, the costs of using an arm roll for- warder are lower, although the loading capacity was small and the hourly operation cost was high. The maximum operational efficiencies varied depending on forwarding distances. The second operation system with an arm roll forwarder exhibited the best operational efficiency within a 1,580-m forwarding distance, and beyond that distance it exhibited the highest operational efficiency when a forwarder was used. Similarly, the cost of operation of the system with an arm roll forwarder was the lowest within a 1,130-m forwarding distance, and beyond that distance the cost was the lowest when using the forwarder. Therefore, the arm roll for- warder is effective within a certain forwarding distance.展开更多
The research of the ergonomic parameters of two tested forwarders was based on the measurement of a variability of physiological functions of the operator during one work shift. The research included a series of six m...The research of the ergonomic parameters of two tested forwarders was based on the measurement of a variability of physiological functions of the operator during one work shift. The research included a series of six measurements, each lasting l h and starting at 5：00, 12：00 and 17：00 O＇clock. The measured operator was at all times the same person. We had a hypothesis that the rate of the measured variability would have to do with the following four factors： forwarder cabin type, terrain character, fatigue during the work shift and work at daylight or in dark. Main findings are described below： during his work with a fixed type of the forwarder cab, the operator＇s brain waves at the frequency of Gamma, high Beta, Beta and Alpha reached statistically significantly higher average values than during his work with a rotating cab. With a higher degree of terrain roughness and in the forwarder with the rotating cab, the operator showed a significantly higher frequency and lower amplitude of respiration. At the beginning of the work shift, the tension of muscles in the operator＇s neck was at the significantly lowest level. In the afternoon, at the end of the work shift, the level of muscle tension was the highest. The “daylight/dark” work had a significantly highest impact on volume changes in the amplitude （strength） of blood pulse and on the skin conductance level. All research factors explained together 15%-65% of the variability of physiological functions.展开更多
Chinese President Xi Jinping has guided China through a year of resilient growth via forward-looking reforms and innovation-driven transformation that is shaping the nation’s economic trajectory for 2026 and beyond.
To investigate the forward kinematics problem of parallel mechanisms with complex limbs and to expand the applicability of the powerful tool of Conformal Geometric Algebra(CGA),a CGA-based modeling and solution method...To investigate the forward kinematics problem of parallel mechanisms with complex limbs and to expand the applicability of the powerful tool of Conformal Geometric Algebra(CGA),a CGA-based modeling and solution method for a class of parallel platforms with 3-RE structure after locking the actuated joints is proposed in this paper.Given that the angle between specific joint axes of limbs remains constant,a set of geometric constraints for the forward kinematics of parallel mechanisms(PM)are determined.After translating unit direction vectors of these joint axes to the common starting point,the geometric constraints of the angle between the vectors are transformed into the distances between the endpoints of the vectors,making them easier to handle.Under the framework of CGA,the positions of key points that determine the position and orientation of the moving platform can be intuitively determined by the intersection,division,and duality of basic geometric entities.By employing the tangent half-angle substitution,the forward kinematic analysis of the parallel mechanisms leads to a high-order univariate polynomial equation without the need for any complex algebraic elimination operations.After solving this equation and back substitution,the position and pose of the MP can be obtained indirectly.A numerical case is utilized to confirm the effectiveness of the proposed method.展开更多
Fluvial systems play a crucial role in coastal and riverine ecosystems, making it essential to understand their responses to sea level changes for preserving biodiversity and managing natural resources. The evolution ...Fluvial systems play a crucial role in coastal and riverine ecosystems, making it essential to understand their responses to sea level changes for preserving biodiversity and managing natural resources. The evolution of the modern Indus River Delta offers a rare opportunity to study the interplay between sea level fluctuations, tectonism, sediment supply, and the corresponding fluvial responses. This study employs the ‘SedSim' stratigraphic forward model to simulate the delta's evolution from 200 kyr to the next5 kyr, drawing on data from field observations, Landsat imagery, digital elevation models, and previous studies. The model consists of 205 layers, each representing a 1-kyr time step, covering the last two glacial-interglacial cycles. Between 200 kyr and 130 kyr, during a lowstand period, sedimentation on the delta plain continued due to partial flow from the Indus River. During the last interglacial(130–60 kyr), rising sea levels led to peak sediment deposition, characteristic of a highstand phase. From 60 kyr to 18 kyr, sea levels dropped to their lowest during the Last Glacial Maximum(LGM), resulting in extensive erosion and minimal deposition on the delta plain. From 18 kyr to the present, rapidly rising sea levels, coupled with intensified monsoon activity, increased sedimentation rates and triggered avulsion and aggradation processes. The model accurately predicted depositional thickness across the delta plain, indicating a maximum of ca. 200 m at the shoreline platform, ca. 175 m in the northeastern delta, and ca. 100 m in the central delta. The study underscores the delta's vulnerability to future sea level rise, which–at a projected rate of 1 m/kyr–could significantly influence the densely populated, low-lying delta plain. These findings offer valuable insights into the geomorphic evolution of the Indus Delta and emphasize the socioeconomic implications of sea level change, underscoring the importance of proactive management and adaptation strategies.展开更多
As a means of quantitative interpretation,forward calculations of the global lithospheric magnetic field in the Spherical Harmonic(SH)domain have been widely used to reveal geophysical,lithological,and geothermal vari...As a means of quantitative interpretation,forward calculations of the global lithospheric magnetic field in the Spherical Harmonic(SH)domain have been widely used to reveal geophysical,lithological,and geothermal variations in the lithosphere.Traditional approaches either do not consider the non-axial dipolar terms of the inducing field and its radial variation or do so by means of complicated formulae.Moreover,existing methods treat the magnetic lithosphere either as an infinitesimally thin layer or as a radially uniform spherical shell of constant thickness.Here,we present alternative forward formulae that account for an arbitrarily high maximum degree of the inducing field and for a magnetic lithosphere of variable thickness.Our simulations based on these formulae suggest that the satellite magnetic anomaly field is sensitive to the non-axial dipolar terms of the inducing field but not to its radial variation.Therefore,in forward and inverse calculations of satellite magnetic anomaly data,the non-axial dipolar terms of the inducing field should not be ignored.Furthermore,our results show that the satellite magnetic anomaly field is sensitive to variability in the lateral thickness of the magnetized shell.In particular,we show that for a given vertically integrated susceptibility distribution,underestimating the thickness of the magnetic layer overestimates the induced magnetic field.This discovery bridges the greatest part of the alleged gap between the susceptibility values measured from rock samples and the susceptibility values required to match the observed magnetic field signal.We expect the formulae and conclusions of this study to be a valuable tool for the quantitative interpretation of the Earth's global lithospheric magnetic field,through an inverse or forward modelling approach.展开更多
Prefabricated twinning represents an effective strategy for optimizing the microstructure of extruded forming components and facilitating changes in texture.The study examines the incorporation of[10-12]twins into an ...Prefabricated twinning represents an effective strategy for optimizing the microstructure of extruded forming components and facilitating changes in texture.The study examines the incorporation of[10-12]twins into an AZ31 magnesium alloy billet via cold pre-upsetting deformation before alternating forward extrusion(CUAFE).The experimental results indicate that the initial presence of[10-12]twins is advantageous for the development of[10-10]and[11-20]texture components during the extrusion process.In addition,different DRX mechanisms have different influences on the evolution of basal texture.The CDRX grains tend to preferentially select the[11-20]texture orientation,weakening the[10-10]texture and enhancing the[11-20]texture.However,most DDRX grains deviate significantly from the orientation of their surrounding original grain and do not have a preferred orientation.This is reflected in the mechanical properties of the CUAFE part.The tensile strength is 323.5 MPa,while the elongation is as high as 20.1%.展开更多
Background:The decreased slowly activating delayed rectifier K+current(IKs)is the molecular basis of arrhythmia caused by myocardial hypertrophy.The aim of this study was to investigate the mechanism of IKs down-regul...Background:The decreased slowly activating delayed rectifier K+current(IKs)is the molecular basis of arrhythmia caused by myocardial hypertrophy.The aim of this study was to investigate the mechanism of IKs down-regulation related to the channel number,as well as the regulation of channel number under pathological conditions.Methods:The HEK 293 cell co-transfected with KCNQ1/KCNE1 genes was cultured conventionally.After the cells incubated with angiotensin II(AngII)(24 h),AngII(72 h),bisindolylmaleimide I(Bis),brefeldin A and dynasore,the effect and relevant mechanism of long term incubation of AngII on the IKs tail current and KCNQ1 channel total protein were investigated by electrophysiology method and western blotting.In the experiment,the Bis,brefeldin A and dynasore could inhibit the protein kinase C(PKC)activity,the forward transport of KCNQ1 channel and the endocytosis of KCNQ1 channel,respectively.At last,the Rab GTPases 11(Rab11)dominant-negative mutant dsRed-Rab11/S25N was infected into the cells to investigate the effect and relevant mechanism of long term AngII incubation on the IKs tail current and KCNQ1 channel total protein.Results:Our results showed that the decreased IKs tail current and the KCNQ1 channel total protein caused by long term AngII incubation were attenuated by Bis treatment,which inhibited PKC activity.In addition,the inhibited IKs tail current and KCNQ1 channel total protein were also alleviated by brefeldin A and dynasore treatment.At last,the expression of Rab11 dominant-negative mutant dsRed-Rab11/S25N could weak the inhibition of IKs tail current and the KCNQ1 channel total protein caused by long term AngII incubation.Conclusion:The long term incubation of AngII inhibited the IKs tail current and KCNQ1 channel total protein was achieved by PKC activation and the disorder of the channel trafficking by Rab11.展开更多
This study presents the development of a Magnesium Alloy Seat Frame(MASF),supported by case studies from automotive original equipment manufacturers.The process covers integrated design,simulation,manufacturing,and te...This study presents the development of a Magnesium Alloy Seat Frame(MASF),supported by case studies from automotive original equipment manufacturers.The process covers integrated design,simulation,manufacturing,and testing,aiming to boost industry confidence in Mg alloy applications.A novel structural design is developed that integrates the headrest with the backrest,achieving a balance between lightweight performance and safety.Structural optimization is guided by stress–strain simulations under diverse conditions within a complete forward development process.Casting simulations are conducted to analyze process characteristics,resulting in a verified MASF yield rate exceeding 90%.The final 9.88 kg MASF represents a 24.6%(3.23 kg)weight reduction versus a steel seat.This research contributes to advancements in defect control technology for large die casting magnesium alloy parts and has broad implications for their application in automotive manufacturing.展开更多
The Earth's magnetic field,which has been extensively observed from ground to satellite altitudes over several decades,originates from multiple sources,such as the core dynamo,the conductive mantle,the magnetized ...The Earth's magnetic field,which has been extensively observed from ground to satellite altitudes over several decades,originates from multiple sources,such as the core dynamo,the conductive mantle,the magnetized lithosphere,and the space current systems.Modeling of the lithospheric contribution plays an important role in the geophysical studies and industrial applications.In this paper,we propose a new method for global and regional modeling of the lithospheric magnetic field based on the cubed-sphere.An equivalent dipole source method on a quasi-uniform cubed-sphere grid is employed in the forward modeling.The dipole directions are fixed according to a priori magnetization and the relative intensities are estimated by an inversion procedure of least-squares fitting with minimum model regularization.Several numerical tests are performed to validate the accuracy and efficiency of both forward modeling and inversion procedure.The proposed method is applied to the global and regional modeling based on the latest magnetic data from Swarm Alpha satellite and MSS-1 mission.The model results indicate that the proposed method works quite well for realistic satellite data and MSS-1 data is consistent with the Swarm data in terms of lithospheric field modeling.展开更多
In this study,we propose a Gram-Charlier expansion approach to investigate the impact of skewness and kurtosis on production and hedging decisions.Consistent with the existing literature,we find that skewness and kurt...In this study,we propose a Gram-Charlier expansion approach to investigate the impact of skewness and kurtosis on production and hedging decisions.Consistent with the existing literature,we find that skewness and kurtosis do not affect decisions regarding optimal production;however,they significantly influence optimal hedging decisions.We observe that positive skewness with platykurtic spot prices or negative skewness with leptokurtic spot prices often leads to over-hedging when the initial forward contract price exceeds its expected value.Conversely,under-hedging is expected when the initial forward contract price falls below its expected value.In other conditions,skewness can either promote or impede speculative future trading.Using the Gram-Charlier expansion of the spot price density function,we find that optimal future positions depend on forward prices,the hedgers’risk preference,and the spot price distribution.Simulations validate our findings on the impact of skewness and kurtosis on future hedging.Finally,we analyze of a cotton storage and forward contracting dataset to illustrate the application of our methodology and support our theoretical results.展开更多
This study presents a novel analytical algorithm for solving the forward position problem of a triangular platform Stewart-type parallel robot(STPR).By introducing a virtual chain and leveraging tetrahedral geometric ...This study presents a novel analytical algorithm for solving the forward position problem of a triangular platform Stewart-type parallel robot(STPR).By introducing a virtual chain and leveraging tetrahedral geometric principles,the proposed method derives analytical solutions for the position and orientation of the moving platform.The algorithm systematically addresses the nonlinearity inherent in the kinematic equations of parallel mechanisms,providing explicit expressions for the coordinates of key moving attachment points.Furthermore,the methodology is extended to general triangular platform STPRs with non-coplanar fixed attachments.Numerical validation through virtual experiments confirms the accuracy of the solutions,demonstrating that the mechanism admits eight distinct configurations for a given set of limb lengths.The results align with established kinematic principles and offer a computationally efficient alternative to iterative analytical approaches,contributing to the advancement of precision control in parallel robotic systems.展开更多
We propose a novel workflow for fast forward modeling of well logs in axially symmetric 2D models of the nearwellbore environment.The approach integrates the finite element method with deep residual neural networks to...We propose a novel workflow for fast forward modeling of well logs in axially symmetric 2D models of the nearwellbore environment.The approach integrates the finite element method with deep residual neural networks to achieve exceptional computational efficiency and accuracy.The workflow is demonstrated through the modeling of wireline electromagnetic propagation resistivity logs,where the measured responses exhibit a highly nonlinear relationship with formation properties.The motivation for this research is the need for advanced modeling al-gorithms that are fast enough for use in modern quantitative interpretation tools,where thousands of simulations may be required in iterative inversion processes.The proposed algorithm achieves a remarkable enhancement in performance,being up to 3000 times faster than the finite element method alone when utilizing a GPU.While still ensuring high accuracy,this makes it well-suited for practical applications when reliable payzone assessment is needed in complex environmental scenarios.Furthermore,the algorithm’s efficiency positions it as a promising tool for stochastic Bayesian inversion,facilitating reliable uncertainty quantification in subsurface property estimation.展开更多
The recovery of ionic liquids(ILs)has attracted growing attention as an indispensable process in“green”industrial applications.Forward osmosis(FO)has proven to be a sustainable method for concentrating the very dilu...The recovery of ionic liquids(ILs)has attracted growing attention as an indispensable process in“green”industrial applications.Forward osmosis(FO)has proven to be a sustainable method for concentrating the very dilute aqueous solutions of ILs at ambient temperature,in which semi-permeable membranes play a vital role in determining the recovery efficiency.Herein,we use interfacial polymerization method to prepare thin-film composite membranes consisting of polyamide skin layer and electrospun nanofibrous substrate with tunable water permeability and IL selectivity for osmotic enrichment of imidazolium ILs from their dilute aqueous solutions through FO process.The resulting FO membrane shows a compact polyamide layer with a thickness of 30-200 nm,guranteeing a high selectivity to ILs and water.Meanwhile,the nanofibrous substrate with large and interconnect pores as well as low tortuosity,providing mechanical and permeable support for the composite membranes.IL structure influences the osmotic pressure difference as well as the interactions with polyamide layer of the membrane and thus determines the whole concentration process.First,the alkyl chain growth augments the osmosis pressure difference between the ILs solution and draw solution,resulting in an enhancement in driving force of water osmosis and IL enrichment.Moreover,alkyl length aggravates external concentration polarization caused by the enhanced adsorption of ILs onto the skin layer via electrostatic and alkyl-πinteractions.Meanwhile,such adsorbed ILs further enhance the IL retention but decrease the reverse salt diffusion.Therefore,imidazolium ILs with varied alkyl lengths are ultimately enriched with a 100-fold increase in concentration from their dilute aqueous solutions with high IL/NaCl rejection and low IL loss.Remarkably,the final concentration of IL with longest alkyl length reaches the highest(6.4 mol·L^(-1)).This work provides the insights in respect to material preparation and process amelioration for IL recovery with high scalability at mild conditions.展开更多
The Rock-soil interface is a common geological interface.Due to mechanical differences between soil and rock,the stress waves generated by underground blasting undergo intense polarization when crossing the rock-soil ...The Rock-soil interface is a common geological interface.Due to mechanical differences between soil and rock,the stress waves generated by underground blasting undergo intense polarization when crossing the rock-soil interface,making propagation laws difficult to predict.Currently,the characteristics of the impact of the rock-soil interface on blasting stress waves remain unclear.Therefore,the vibration field caused by cylindrical charge blasting in elastic rock and partial-saturation poro-viscoelastic soil was solved.A forward algorithm for the underground blasting vibration field in rock-soil sites was proposed,considering medium damping and geometric diffusion effects of stress waves.Further investigation into the influence of rock and soil parameters and blasting source parameters revealed the following conclusions:stress waves in soil exhibit dispersion,causing peak particle velocity(PPV)to display a discrete distribution.Soil parameters affect PPV attenuation only within the soil,while blasting source parameters affect PPV attenuation throughout the entire site.Multi-wave coupling effects induced by the rocksoil interface result in zones of enhanced and attenuated PPV within the site.The size of the enhancement zone is inversely correlated with the distance from the blasting source and positively correlated with the blasting source attenuation rate and burial depth,providing guidance for selecting explosives and blasting positions.Additionally,PPV attenuation rate increases with distance from the rock-soil interface,but an amplification effect occurs near the interface,most noticeable at 0.1 m.Thus,a sufficient safety distance from the rock-soil interface is necessary during underground blasting.展开更多
Seawater electrolysis for hydrogen production faces inherent challenges, including side reactions, corrosion, and scaling, stemming from the intricate composition of seawater. In response, researchers have turned to c...Seawater electrolysis for hydrogen production faces inherent challenges, including side reactions, corrosion, and scaling, stemming from the intricate composition of seawater. In response, researchers have turned to continuous water splitting using forward osmosis(FO)-driven seawater desalination. However, the necessity of a neutral electrolyte hampers this strategy due to the limited current density and scarcity of precious metals. Herein, this study applies alkali-durable FO membranes to enable self-sustaining seawater splitting, which can selectively withdraw water molecules, from seawater, via concentration gradient. The membranes demonstrates outstanding perm-selectivity of water/ions(~5830 mol mol^(-1)) during month-long alkaline resistance tests, preventing electrolyte leaching(>97% OHàretention) while maintaining ~95%water balance(V_(FO)= V_(electrolysis)) via preserved concentration gradient for consistent forward-osmosis influx of water molecules. With the consistent electrolyte environment protected by the polyamide FO membranes, the Ni Fe-Ar-P catalyst exhibits promising performance: a sustain current density of 360 m A cmà2maintained at the cell voltage of 2.10 V and 2.15 V for 360 h in the offshore seawater, preventing Cl/Br corrosion(98% rejection) and Mg/Ca passivation(99.6% rejection). This research marks a significant advancement towards efficient and durable seawater-based hydrogen production.展开更多
Rotor-to-rotor interaction among neighboring rotors of a multirotor has great significance for aerodynamically efficient multirotor design. Current research is conducted to analyze aerodynamic performance of different...Rotor-to-rotor interaction among neighboring rotors of a multirotor has great significance for aerodynamically efficient multirotor design. Current research is conducted to analyze aerodynamic performance of different octocopter configurations amid hover and forward flight. Conventional and coaxial configurations are studied and a hybrid configuration is also proposed to rectify the disadvantages associated with the earlier two. Comparison is carried out for the aforementioned configurations along with comparison of coaxial and hybrid octocopters with bigger diameter rotors in the same confined space for high thrust requirement missions. Vertical spacing of coaxial configuration is also studied. Virtual Blade Method (VBM) is considered herein due to its great computational efficiency. The results show that there are 11.89% and 14.22% loss in thrust for coaxial octocopter compared to conventional and hybrid configurations with normal size rotors and 15.61% loss compared to hybrid configuration with bigger rotors in hover, whereas coaxial square configuration performs the worst in forward flight with a lift loss of 9.1%, 14.77% and 18.8% compared to coaxial diamond, conventional and hybrid configurations with normal size rotors and 9.96% and 17.82% loss compared to coaxial diamond and hybrid configurations with bigger rotors. Combined FM shows that hybrid configuration outperforms other octocopter configurations in overall aerodynamic performance.展开更多
Multifocal metalenses are of great concern in optical communications,optical imaging and micro-optics systems,but their design is extremely challenging.In recent years,deep learning methods have provided novel solutio...Multifocal metalenses are of great concern in optical communications,optical imaging and micro-optics systems,but their design is extremely challenging.In recent years,deep learning methods have provided novel solutions to the design of optical planar devices.Here,an approach is proposed to explore the use of generative adversarial networks(GANs)to realize the design of metalenses with different focusing positions at dual wavelengths.This approach includes a forward network and an inverse network,where the former predicts the optical response of meta-atoms and the latter generates structures that meet specific requirements.Compared to the traditional search method,the inverse network demonstrates higher precision and efficiency in designing a dual-wavelength bifocal metalens.The results will provide insights and methodologies for the design of tunable wavelength metalenses,while also highlighting the potential of deep learning in optical device design.展开更多
Parallel mechanisms with fewer degrees of freedom that incorporate two or more SPR limbs have been widely adopted in industrial applications in recent years.However,notable theoretical gaps persist,particularly in the...Parallel mechanisms with fewer degrees of freedom that incorporate two or more SPR limbs have been widely adopted in industrial applications in recent years.However,notable theoretical gaps persist,particularly in the field of analytical solutions for forward kinematics.To address this,this paper proposes an innovative forward kinematics analysis method based on Conformal Geometric Algebra(CGA)for complex hybrid mechanisms formed by serial concatenation of such parallel mechanisms.The method efficiently represents geometric elements and their operational relationships by defining appropriate unknown parameters.It constructs fundamental geometric objects such as spheres and planes,derives vertex expressions through intersection and dual operations,and establishes univariate high-order equations via inner product operations,ultimately obtaining complete analytical solutions for the forward kinematics of hybrid mechanisms.Using the(2-SPR+RPS)+(3-SPR)serial-parallel hybrid mechanism as a validation case,three configuration tests implemented in Mathematica demonstrate that:for each configuration,the upper 3-SPR mechanism yields 15 mathematical solutions,while the lower 2-SPR+RPS mechanism yields 4 mathematical solutions.After geometric constraint filtering,a unique physically valid solution is obtained for each mechanism.SolidWorks simulations further verify the correctness and reliability of the model.This research provides a reliable analytical method for forward kinematics of hybrid mechanisms,holding significant implications for advancing their applications in high-precision scenarios.展开更多
文摘We investigated a developed arm roll forwarder at Nasu in Tochigi Prefecture, Japan. An arm roll forwarder can only load a steel container that has been fully loaded with logs beforehand, and can later unload such a container. Such a forwarder can shorten the loading and untoading times and improve operational efficiency. We examined two operation systems with an arm roll forwarder and a forwarder. In the first system the loading was done with a grapple-loader. In the second system the loading was done with a processor. The loading times of an arm roll forwarder were significantly tess than those of a forwarder. Because the optimal cycle times （excluding the waiting times for an arm roll for- warder） were significantly reduced, the costs of using an arm roll for- warder are lower, although the loading capacity was small and the hourly operation cost was high. The maximum operational efficiencies varied depending on forwarding distances. The second operation system with an arm roll forwarder exhibited the best operational efficiency within a 1,580-m forwarding distance, and beyond that distance it exhibited the highest operational efficiency when a forwarder was used. Similarly, the cost of operation of the system with an arm roll forwarder was the lowest within a 1,130-m forwarding distance, and beyond that distance the cost was the lowest when using the forwarder. Therefore, the arm roll for- warder is effective within a certain forwarding distance.
文摘The research of the ergonomic parameters of two tested forwarders was based on the measurement of a variability of physiological functions of the operator during one work shift. The research included a series of six measurements, each lasting l h and starting at 5：00, 12：00 and 17：00 O＇clock. The measured operator was at all times the same person. We had a hypothesis that the rate of the measured variability would have to do with the following four factors： forwarder cabin type, terrain character, fatigue during the work shift and work at daylight or in dark. Main findings are described below： during his work with a fixed type of the forwarder cab, the operator＇s brain waves at the frequency of Gamma, high Beta, Beta and Alpha reached statistically significantly higher average values than during his work with a rotating cab. With a higher degree of terrain roughness and in the forwarder with the rotating cab, the operator showed a significantly higher frequency and lower amplitude of respiration. At the beginning of the work shift, the tension of muscles in the operator＇s neck was at the significantly lowest level. In the afternoon, at the end of the work shift, the level of muscle tension was the highest. The “daylight/dark” work had a significantly highest impact on volume changes in the amplitude （strength） of blood pulse and on the skin conductance level. All research factors explained together 15%-65% of the variability of physiological functions.
文摘Chinese President Xi Jinping has guided China through a year of resilient growth via forward-looking reforms and innovation-driven transformation that is shaping the nation’s economic trajectory for 2026 and beyond.
基金Supported by National Natural Science Foundation of China (Grant No. 52175019)Beijing Municipal Natural Science Foundation of China (Grant No. L222038)+3 种基金Beijing Nova Programme Interdisciplinary Cooperation Project of China (Grant No. 20240484699)Joint Funds of Industry-University-Research of Shanghai Academy of Spaceflight Technology of China (Grant No. SAST2022-017)Beijing Municipal Key Laboratory of Space-ground Interconnection and Convergence of ChinaKey Laboratory of IoT Monitoring and Early Warning,Ministry of Emergency Management of China
文摘To investigate the forward kinematics problem of parallel mechanisms with complex limbs and to expand the applicability of the powerful tool of Conformal Geometric Algebra(CGA),a CGA-based modeling and solution method for a class of parallel platforms with 3-RE structure after locking the actuated joints is proposed in this paper.Given that the angle between specific joint axes of limbs remains constant,a set of geometric constraints for the forward kinematics of parallel mechanisms(PM)are determined.After translating unit direction vectors of these joint axes to the common starting point,the geometric constraints of the angle between the vectors are transformed into the distances between the endpoints of the vectors,making them easier to handle.Under the framework of CGA,the positions of key points that determine the position and orientation of the moving platform can be intuitively determined by the intersection,division,and duality of basic geometric entities.By employing the tangent half-angle substitution,the forward kinematic analysis of the parallel mechanisms leads to a high-order univariate polynomial equation without the need for any complex algebraic elimination operations.After solving this equation and back substitution,the position and pose of the MP can be obtained indirectly.A numerical case is utilized to confirm the effectiveness of the proposed method.
基金the Science and Technology Innovation Project of the Laoshan Laboratory (No. LSKJ202203402)the Major Research Project on the Tethys Geodynamic System from the National Science Foundation of China (No. 92055204)。
文摘Fluvial systems play a crucial role in coastal and riverine ecosystems, making it essential to understand their responses to sea level changes for preserving biodiversity and managing natural resources. The evolution of the modern Indus River Delta offers a rare opportunity to study the interplay between sea level fluctuations, tectonism, sediment supply, and the corresponding fluvial responses. This study employs the ‘SedSim' stratigraphic forward model to simulate the delta's evolution from 200 kyr to the next5 kyr, drawing on data from field observations, Landsat imagery, digital elevation models, and previous studies. The model consists of 205 layers, each representing a 1-kyr time step, covering the last two glacial-interglacial cycles. Between 200 kyr and 130 kyr, during a lowstand period, sedimentation on the delta plain continued due to partial flow from the Indus River. During the last interglacial(130–60 kyr), rising sea levels led to peak sediment deposition, characteristic of a highstand phase. From 60 kyr to 18 kyr, sea levels dropped to their lowest during the Last Glacial Maximum(LGM), resulting in extensive erosion and minimal deposition on the delta plain. From 18 kyr to the present, rapidly rising sea levels, coupled with intensified monsoon activity, increased sedimentation rates and triggered avulsion and aggradation processes. The model accurately predicted depositional thickness across the delta plain, indicating a maximum of ca. 200 m at the shoreline platform, ca. 175 m in the northeastern delta, and ca. 100 m in the central delta. The study underscores the delta's vulnerability to future sea level rise, which–at a projected rate of 1 m/kyr–could significantly influence the densely populated, low-lying delta plain. These findings offer valuable insights into the geomorphic evolution of the Indus Delta and emphasize the socioeconomic implications of sea level change, underscoring the importance of proactive management and adaptation strategies.
基金supported by the National Natural Science Foundation of China(Grant Nos.42250103 and 42174090)the Opening Fund of Key Laboratory of Geological Survey and Evaluation of Ministry of Education(Grant No.GLAB2023ZR02)the Ministry of Science and Technology(MOST)Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources(Grant No.MSFGPMR2022-4)。
文摘As a means of quantitative interpretation,forward calculations of the global lithospheric magnetic field in the Spherical Harmonic(SH)domain have been widely used to reveal geophysical,lithological,and geothermal variations in the lithosphere.Traditional approaches either do not consider the non-axial dipolar terms of the inducing field and its radial variation or do so by means of complicated formulae.Moreover,existing methods treat the magnetic lithosphere either as an infinitesimally thin layer or as a radially uniform spherical shell of constant thickness.Here,we present alternative forward formulae that account for an arbitrarily high maximum degree of the inducing field and for a magnetic lithosphere of variable thickness.Our simulations based on these formulae suggest that the satellite magnetic anomaly field is sensitive to the non-axial dipolar terms of the inducing field but not to its radial variation.Therefore,in forward and inverse calculations of satellite magnetic anomaly data,the non-axial dipolar terms of the inducing field should not be ignored.Furthermore,our results show that the satellite magnetic anomaly field is sensitive to variability in the lateral thickness of the magnetized shell.In particular,we show that for a given vertically integrated susceptibility distribution,underestimating the thickness of the magnetic layer overestimates the induced magnetic field.This discovery bridges the greatest part of the alleged gap between the susceptibility values measured from rock samples and the susceptibility values required to match the observed magnetic field signal.We expect the formulae and conclusions of this study to be a valuable tool for the quantitative interpretation of the Earth's global lithospheric magnetic field,through an inverse or forward modelling approach.
基金supported by the National Natural Science Foundation of China(No.52475341).
文摘Prefabricated twinning represents an effective strategy for optimizing the microstructure of extruded forming components and facilitating changes in texture.The study examines the incorporation of[10-12]twins into an AZ31 magnesium alloy billet via cold pre-upsetting deformation before alternating forward extrusion(CUAFE).The experimental results indicate that the initial presence of[10-12]twins is advantageous for the development of[10-10]and[11-20]texture components during the extrusion process.In addition,different DRX mechanisms have different influences on the evolution of basal texture.The CDRX grains tend to preferentially select the[11-20]texture orientation,weakening the[10-10]texture and enhancing the[11-20]texture.However,most DDRX grains deviate significantly from the orientation of their surrounding original grain and do not have a preferred orientation.This is reflected in the mechanical properties of the CUAFE part.The tensile strength is 323.5 MPa,while the elongation is as high as 20.1%.
基金supported by the National Natural Science Foundation of China(NSFC)Youth Project(No.82204397 and No.22203063).
文摘Background:The decreased slowly activating delayed rectifier K+current(IKs)is the molecular basis of arrhythmia caused by myocardial hypertrophy.The aim of this study was to investigate the mechanism of IKs down-regulation related to the channel number,as well as the regulation of channel number under pathological conditions.Methods:The HEK 293 cell co-transfected with KCNQ1/KCNE1 genes was cultured conventionally.After the cells incubated with angiotensin II(AngII)(24 h),AngII(72 h),bisindolylmaleimide I(Bis),brefeldin A and dynasore,the effect and relevant mechanism of long term incubation of AngII on the IKs tail current and KCNQ1 channel total protein were investigated by electrophysiology method and western blotting.In the experiment,the Bis,brefeldin A and dynasore could inhibit the protein kinase C(PKC)activity,the forward transport of KCNQ1 channel and the endocytosis of KCNQ1 channel,respectively.At last,the Rab GTPases 11(Rab11)dominant-negative mutant dsRed-Rab11/S25N was infected into the cells to investigate the effect and relevant mechanism of long term AngII incubation on the IKs tail current and KCNQ1 channel total protein.Results:Our results showed that the decreased IKs tail current and the KCNQ1 channel total protein caused by long term AngII incubation were attenuated by Bis treatment,which inhibited PKC activity.In addition,the inhibited IKs tail current and KCNQ1 channel total protein were also alleviated by brefeldin A and dynasore treatment.At last,the expression of Rab11 dominant-negative mutant dsRed-Rab11/S25N could weak the inhibition of IKs tail current and the KCNQ1 channel total protein caused by long term AngII incubation.Conclusion:The long term incubation of AngII inhibited the IKs tail current and KCNQ1 channel total protein was achieved by PKC activation and the disorder of the channel trafficking by Rab11.
基金supported in part by the project is supported partly by National Key Research and Development Program of China(no.2022YFB2503504)Chongqing Technology Innovation and Application Development Project(no.CSTB2022TIAD-DEX0011)China Scholarship Council.
文摘This study presents the development of a Magnesium Alloy Seat Frame(MASF),supported by case studies from automotive original equipment manufacturers.The process covers integrated design,simulation,manufacturing,and testing,aiming to boost industry confidence in Mg alloy applications.A novel structural design is developed that integrates the headrest with the backrest,achieving a balance between lightweight performance and safety.Structural optimization is guided by stress–strain simulations under diverse conditions within a complete forward development process.Casting simulations are conducted to analyze process characteristics,resulting in a verified MASF yield rate exceeding 90%.The final 9.88 kg MASF represents a 24.6%(3.23 kg)weight reduction versus a steel seat.This research contributes to advancements in defect control technology for large die casting magnesium alloy parts and has broad implications for their application in automotive manufacturing.
基金supported by the National Natural Science Foundation of China(42250101,42250102,42250103,12250013)the Macao Foundation。
文摘The Earth's magnetic field,which has been extensively observed from ground to satellite altitudes over several decades,originates from multiple sources,such as the core dynamo,the conductive mantle,the magnetized lithosphere,and the space current systems.Modeling of the lithospheric contribution plays an important role in the geophysical studies and industrial applications.In this paper,we propose a new method for global and regional modeling of the lithospheric magnetic field based on the cubed-sphere.An equivalent dipole source method on a quasi-uniform cubed-sphere grid is employed in the forward modeling.The dipole directions are fixed according to a priori magnetization and the relative intensities are estimated by an inversion procedure of least-squares fitting with minimum model regularization.Several numerical tests are performed to validate the accuracy and efficiency of both forward modeling and inversion procedure.The proposed method is applied to the global and regional modeling based on the latest magnetic data from Swarm Alpha satellite and MSS-1 mission.The model results indicate that the proposed method works quite well for realistic satellite data and MSS-1 data is consistent with the Swarm data in terms of lithospheric field modeling.
文摘In this study,we propose a Gram-Charlier expansion approach to investigate the impact of skewness and kurtosis on production and hedging decisions.Consistent with the existing literature,we find that skewness and kurtosis do not affect decisions regarding optimal production;however,they significantly influence optimal hedging decisions.We observe that positive skewness with platykurtic spot prices or negative skewness with leptokurtic spot prices often leads to over-hedging when the initial forward contract price exceeds its expected value.Conversely,under-hedging is expected when the initial forward contract price falls below its expected value.In other conditions,skewness can either promote or impede speculative future trading.Using the Gram-Charlier expansion of the spot price density function,we find that optimal future positions depend on forward prices,the hedgers’risk preference,and the spot price distribution.Simulations validate our findings on the impact of skewness and kurtosis on future hedging.Finally,we analyze of a cotton storage and forward contracting dataset to illustrate the application of our methodology and support our theoretical results.
基金supported by the Opening Project of State Key Laboratory of Mechanical Transmission for Advanced Equipment(No.SKLMT-MSKFKT202330)the National Natural Science Foundation of China(No.52575022)the Jiangsu Province Postgraduate Research&Practice Innovation Program(No.KYCX25_1403)。
文摘This study presents a novel analytical algorithm for solving the forward position problem of a triangular platform Stewart-type parallel robot(STPR).By introducing a virtual chain and leveraging tetrahedral geometric principles,the proposed method derives analytical solutions for the position and orientation of the moving platform.The algorithm systematically addresses the nonlinearity inherent in the kinematic equations of parallel mechanisms,providing explicit expressions for the coordinates of key moving attachment points.Furthermore,the methodology is extended to general triangular platform STPRs with non-coplanar fixed attachments.Numerical validation through virtual experiments confirms the accuracy of the solutions,demonstrating that the mechanism admits eight distinct configurations for a given set of limb lengths.The results align with established kinematic principles and offer a computationally efficient alternative to iterative analytical approaches,contributing to the advancement of precision control in parallel robotic systems.
基金financially supported by the Russian federal research project No.FWZZ-2022-0026“Innovative aspects of electro-dynamics in problems of exploration and oilfield geophysics”.
文摘We propose a novel workflow for fast forward modeling of well logs in axially symmetric 2D models of the nearwellbore environment.The approach integrates the finite element method with deep residual neural networks to achieve exceptional computational efficiency and accuracy.The workflow is demonstrated through the modeling of wireline electromagnetic propagation resistivity logs,where the measured responses exhibit a highly nonlinear relationship with formation properties.The motivation for this research is the need for advanced modeling al-gorithms that are fast enough for use in modern quantitative interpretation tools,where thousands of simulations may be required in iterative inversion processes.The proposed algorithm achieves a remarkable enhancement in performance,being up to 3000 times faster than the finite element method alone when utilizing a GPU.While still ensuring high accuracy,this makes it well-suited for practical applications when reliable payzone assessment is needed in complex environmental scenarios.Furthermore,the algorithm’s efficiency positions it as a promising tool for stochastic Bayesian inversion,facilitating reliable uncertainty quantification in subsurface property estimation.
基金supported by the National Natural Science Foundation of China(No.52173095)the MOE Key Laboratory of Macromolecular Synthesis and Functionalization,Zhejiang University(No.2023MSF05)。
文摘The recovery of ionic liquids(ILs)has attracted growing attention as an indispensable process in“green”industrial applications.Forward osmosis(FO)has proven to be a sustainable method for concentrating the very dilute aqueous solutions of ILs at ambient temperature,in which semi-permeable membranes play a vital role in determining the recovery efficiency.Herein,we use interfacial polymerization method to prepare thin-film composite membranes consisting of polyamide skin layer and electrospun nanofibrous substrate with tunable water permeability and IL selectivity for osmotic enrichment of imidazolium ILs from their dilute aqueous solutions through FO process.The resulting FO membrane shows a compact polyamide layer with a thickness of 30-200 nm,guranteeing a high selectivity to ILs and water.Meanwhile,the nanofibrous substrate with large and interconnect pores as well as low tortuosity,providing mechanical and permeable support for the composite membranes.IL structure influences the osmotic pressure difference as well as the interactions with polyamide layer of the membrane and thus determines the whole concentration process.First,the alkyl chain growth augments the osmosis pressure difference between the ILs solution and draw solution,resulting in an enhancement in driving force of water osmosis and IL enrichment.Moreover,alkyl length aggravates external concentration polarization caused by the enhanced adsorption of ILs onto the skin layer via electrostatic and alkyl-πinteractions.Meanwhile,such adsorbed ILs further enhance the IL retention but decrease the reverse salt diffusion.Therefore,imidazolium ILs with varied alkyl lengths are ultimately enriched with a 100-fold increase in concentration from their dilute aqueous solutions with high IL/NaCl rejection and low IL loss.Remarkably,the final concentration of IL with longest alkyl length reaches the highest(6.4 mol·L^(-1)).This work provides the insights in respect to material preparation and process amelioration for IL recovery with high scalability at mild conditions.
基金supported by the National Natural Science Foundation of China(Grant Nos.41972286 and 42102329).
文摘The Rock-soil interface is a common geological interface.Due to mechanical differences between soil and rock,the stress waves generated by underground blasting undergo intense polarization when crossing the rock-soil interface,making propagation laws difficult to predict.Currently,the characteristics of the impact of the rock-soil interface on blasting stress waves remain unclear.Therefore,the vibration field caused by cylindrical charge blasting in elastic rock and partial-saturation poro-viscoelastic soil was solved.A forward algorithm for the underground blasting vibration field in rock-soil sites was proposed,considering medium damping and geometric diffusion effects of stress waves.Further investigation into the influence of rock and soil parameters and blasting source parameters revealed the following conclusions:stress waves in soil exhibit dispersion,causing peak particle velocity(PPV)to display a discrete distribution.Soil parameters affect PPV attenuation only within the soil,while blasting source parameters affect PPV attenuation throughout the entire site.Multi-wave coupling effects induced by the rocksoil interface result in zones of enhanced and attenuated PPV within the site.The size of the enhancement zone is inversely correlated with the distance from the blasting source and positively correlated with the blasting source attenuation rate and burial depth,providing guidance for selecting explosives and blasting positions.Additionally,PPV attenuation rate increases with distance from the rock-soil interface,but an amplification effect occurs near the interface,most noticeable at 0.1 m.Thus,a sufficient safety distance from the rock-soil interface is necessary during underground blasting.
基金funding provided by the National Key R&D Program of China (Grant No. 2021YFB3801301)National Natural Science Foundation of China (Grant Nos. 22075076, 22208097 and 22378119)Shanghai Pilot Program for Basic Research (22TQ1400100-4)。
文摘Seawater electrolysis for hydrogen production faces inherent challenges, including side reactions, corrosion, and scaling, stemming from the intricate composition of seawater. In response, researchers have turned to continuous water splitting using forward osmosis(FO)-driven seawater desalination. However, the necessity of a neutral electrolyte hampers this strategy due to the limited current density and scarcity of precious metals. Herein, this study applies alkali-durable FO membranes to enable self-sustaining seawater splitting, which can selectively withdraw water molecules, from seawater, via concentration gradient. The membranes demonstrates outstanding perm-selectivity of water/ions(~5830 mol mol^(-1)) during month-long alkaline resistance tests, preventing electrolyte leaching(>97% OHàretention) while maintaining ~95%water balance(V_(FO)= V_(electrolysis)) via preserved concentration gradient for consistent forward-osmosis influx of water molecules. With the consistent electrolyte environment protected by the polyamide FO membranes, the Ni Fe-Ar-P catalyst exhibits promising performance: a sustain current density of 360 m A cmà2maintained at the cell voltage of 2.10 V and 2.15 V for 360 h in the offshore seawater, preventing Cl/Br corrosion(98% rejection) and Mg/Ca passivation(99.6% rejection). This research marks a significant advancement towards efficient and durable seawater-based hydrogen production.
基金supported by the National Natural Science Foundation of China(No.11972190).
文摘Rotor-to-rotor interaction among neighboring rotors of a multirotor has great significance for aerodynamically efficient multirotor design. Current research is conducted to analyze aerodynamic performance of different octocopter configurations amid hover and forward flight. Conventional and coaxial configurations are studied and a hybrid configuration is also proposed to rectify the disadvantages associated with the earlier two. Comparison is carried out for the aforementioned configurations along with comparison of coaxial and hybrid octocopters with bigger diameter rotors in the same confined space for high thrust requirement missions. Vertical spacing of coaxial configuration is also studied. Virtual Blade Method (VBM) is considered herein due to its great computational efficiency. The results show that there are 11.89% and 14.22% loss in thrust for coaxial octocopter compared to conventional and hybrid configurations with normal size rotors and 15.61% loss compared to hybrid configuration with bigger rotors in hover, whereas coaxial square configuration performs the worst in forward flight with a lift loss of 9.1%, 14.77% and 18.8% compared to coaxial diamond, conventional and hybrid configurations with normal size rotors and 9.96% and 17.82% loss compared to coaxial diamond and hybrid configurations with bigger rotors. Combined FM shows that hybrid configuration outperforms other octocopter configurations in overall aerodynamic performance.
基金National Natural Science Foundation of China(No.61975029)。
文摘Multifocal metalenses are of great concern in optical communications,optical imaging and micro-optics systems,but their design is extremely challenging.In recent years,deep learning methods have provided novel solutions to the design of optical planar devices.Here,an approach is proposed to explore the use of generative adversarial networks(GANs)to realize the design of metalenses with different focusing positions at dual wavelengths.This approach includes a forward network and an inverse network,where the former predicts the optical response of meta-atoms and the latter generates structures that meet specific requirements.Compared to the traditional search method,the inverse network demonstrates higher precision and efficiency in designing a dual-wavelength bifocal metalens.The results will provide insights and methodologies for the design of tunable wavelength metalenses,while also highlighting the potential of deep learning in optical device design.
基金Supported by Hebei Provincial Natural Science Foundation(Grant No.F2024202052)National Natural Science Foundation of China(Grant No.52175019)+3 种基金Beijing Municipal Natural Science Foundation(Grant No.L222038)Beijing Nova Programme Interdisciplinary Cooperation Project(Grant No.20240484699)Joint Funds of Industry-University-Research of Shanghai Academy of Spaceflight Technology(Grant No.SAST2022-017)Beijing Municipal Key Laboratory of Space-ground Interconnection and Convergence of China and Key Laboratory of IoT Monitoring and Early Warning,Ministry of Emergency Management。
文摘Parallel mechanisms with fewer degrees of freedom that incorporate two or more SPR limbs have been widely adopted in industrial applications in recent years.However,notable theoretical gaps persist,particularly in the field of analytical solutions for forward kinematics.To address this,this paper proposes an innovative forward kinematics analysis method based on Conformal Geometric Algebra(CGA)for complex hybrid mechanisms formed by serial concatenation of such parallel mechanisms.The method efficiently represents geometric elements and their operational relationships by defining appropriate unknown parameters.It constructs fundamental geometric objects such as spheres and planes,derives vertex expressions through intersection and dual operations,and establishes univariate high-order equations via inner product operations,ultimately obtaining complete analytical solutions for the forward kinematics of hybrid mechanisms.Using the(2-SPR+RPS)+(3-SPR)serial-parallel hybrid mechanism as a validation case,three configuration tests implemented in Mathematica demonstrate that:for each configuration,the upper 3-SPR mechanism yields 15 mathematical solutions,while the lower 2-SPR+RPS mechanism yields 4 mathematical solutions.After geometric constraint filtering,a unique physically valid solution is obtained for each mechanism.SolidWorks simulations further verify the correctness and reliability of the model.This research provides a reliable analytical method for forward kinematics of hybrid mechanisms,holding significant implications for advancing their applications in high-precision scenarios.
