The growing need for sustainable energy solutions,driven by rising energy shortages,environmental concerns,and the depletion of conventional energy sources,has led to a significant focus on renewable energy.Solar ener...The growing need for sustainable energy solutions,driven by rising energy shortages,environmental concerns,and the depletion of conventional energy sources,has led to a significant focus on renewable energy.Solar energy,among the various renewable sources,is particularly appealing due to its abundant availability.However,the efficiency of commercial solar photovoltaic(PV)modules is hindered by several factors,notably their conversion efficiency,which averages around 19%.This efficiency can further decline to 10%–16%due to temperature increases during peak sunlight hours.This study investigates the cooling of PV modules by applying water to their front surface through Computational fluid dynamics(CFD).The study aimed to determine the optimal conditions for cooling the PV module by analyzing the interplay between water film thickness,Reynolds number,and their effects on temperature reduction and heat transfer.The CFD analysis revealed that the most effective cooling condition occurred with a 5 mm thick water film and a Reynolds number of 10.These specific parameters were found to maximize the heat transfer and temperature reduction efficiency.This finding is crucial for the development of practical and efficient cooling systems for PV modules,potentially leading to improved performance and longevity of solar panels.Alternative cooling fluids or advanced cooling techniques that might offer even better efficiency or practical benefits.展开更多
Huge calculation burden and difficulty in convergence are the two central conundrums of nonlinear topology optimization(NTO).To this end,a multi-resolution nonlinear topology optimization(MR-NTO)method is proposed bas...Huge calculation burden and difficulty in convergence are the two central conundrums of nonlinear topology optimization(NTO).To this end,a multi-resolution nonlinear topology optimization(MR-NTO)method is proposed based on the multiresolution design strategy(MRDS)and the additive hyperelasticity technique(AHT),taking into account the geometric nonlinearity and material nonlinearity.The MR-NTO strategy is established in the framework of the solid isotropic material with penalization(SIMP)method,while the Neo-Hookean hyperelastic material model characterizes the material nonlinearity.The coarse analysis grid is employed for finite element(FE)calculation,and the fine material grid is applied to describe the material configuration.To alleviate the convergence problem and reduce sensitivity calculation complexity,the software ANSYS coupled with AHT is utilized to perform the nonlinear FE calculation.A strategy for redistributing strain energy is proposed during the sensitivity analysis,i.e.,transforming the strain energy of the analysis element into that of the material element,including Neo-Hooken and second-order Yeoh material.Numerical examples highlight three distinct advantages of the proposed method,i.e.,it can(1)significantly improve the computational efficiency,(2)make up for the shortcoming that NTO based on AHT may have difficulty in convergence when solving the NTO problem,especially for 3D problems,(3)successfully cope with high-resolution 3D complex NTO problems on a personal computer.展开更多
As a connection between the process and the circuit design, the device model is greatly desired for emerging devices, such as the double-gate MOSFET. Time efficiency is one of the most important requirements for devic...As a connection between the process and the circuit design, the device model is greatly desired for emerging devices, such as the double-gate MOSFET. Time efficiency is one of the most important requirements for device modeling. In this paper, an improvement to the computational efficiency of the drain current model for double-gate MOSFETs is extended, and different calculation methods are compared and discussed. The results show that the calculation speed of the improved model is substantially enhanced. A two-dimensional device simulation is performed to verify the improved model. Furthermore, the model is implemented into the HSPICE circuit simulator in Verilog-A for practical application.展开更多
The four-decade quest for synthesizing ambient-stable polymeric nitrogen,a promising high-energy-density material,remains an unsolved challenge in materials science.We develop a multi-stage computational strategy empl...The four-decade quest for synthesizing ambient-stable polymeric nitrogen,a promising high-energy-density material,remains an unsolved challenge in materials science.We develop a multi-stage computational strategy employing density functional tight-binding-based rapid screening combined with density functional theory refinement and global structure searching,effectively bridging computational efficiency with quantum accuracy.This integrated approach identifies four novel polymeric nitrogen phases(Fddd,P3221,I4m2,and𝑃P6522)that are thermodynamically stable at ambient pressure.Remarkably,the helical𝑃6522 configuration demonstrates exceptional thermal resilience up to 1500 K,representing a predicted polymeric nitrogen structure that maintains stability under both atmospheric pressure and high-temperature extremes.Our methodology establishes a paradigm-shifting framework for the accelerated discovery of metastable energetic materials,resolving critical bottlenecks in theoretical predictions while providing experimentally actionable targets for polymeric nitrogen synthesis.展开更多
Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosyste...Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosystems.However,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain unclear.This study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–2020.Results indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the northwest.Areas manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,respectively.Remarkably,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of increase.Environmental factors accounted for 70.79%of the variability in WUE.The leaf area index and temperature served as the major driving forces of WUE variation.展开更多
Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling.However,the conventional trochoidal tool path presents challenges such as lowe...Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling.However,the conventional trochoidal tool path presents challenges such as lower machining efficiency and longer machining time due to its time-varying cutter-workpiece engagement angle and a high percentage of non-cutting tool paths.To address these issues,this paper introduces a parameter-variant trochoidal-like(PVTR)tool path planning method for chatter-free and high-efficiency milling.This method ensures a constant engagement angle for each tool path period by adjusting the trochoidal radius and step.Initially,the nonlinear equation for the PVTR toolpath is established.Then,a segmented recurrence method is proposed to plan tool paths based on the desired engagement angle.The impact of trochoidal tool path parameters on the engagement angle is analyzed and coupled this information with the milling stability model based on spindle speed and engagement angle to determine the desired engagement angle throughout the machining process.Finally,several experimental tests are carried out using the bull-nose end mill to validate the feasibility and effectiveness of the proposed method.展开更多
Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal condu...Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal conductivities of phase-change materials(PCMs)promote Joule heating dissi-pation.Repeated phase transitions also induce long-range atomic diffusion,limiting the durability.To address these challenges,phase-change heterostructure(PCH)devices that incorporate confinement sub-layers based on transition-metal dichalcogenide materials have been developed.In this study,we engi-neered a PCH device by integrating HfTe_(2),which has low thermal conductivity and excellent stability,into the PCM to realize PCRAM with enhanced thermal efficiency and structural stability.HEAT sim-ulations were conducted to validate the superior heat confinement in the programming region of the HfTe_(2)-based PCH device.Moreover,electrical measurements of the device demonstrated its outstanding performance,which was characterized by a low RESET current(∼1.6 mA),stable two-order ON/OFF ratio,and exceptional cycling endurance(∼2×10^(7)).The structural integrity of the HfTe_(2)confinement sub-layer was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy.The material properties,including electrical conductivity,cohesive energy,and electronegativity,substantiated these findings.Collectively,these results revealed that the HfTe_(2)-based PCH device can achieve significant improvements in performance and reliability compared with conventional PCRAM devices.展开更多
Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration eff...Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration efficiency,complex denitration system,and high investment and operating cost.Here we put forward a novel polymer non-catalytic reduction(PNCR)technology that utilized a new type of polymer agent to remove NO_(x),and the proposed PNCR technology was applied to the existing waste-to-energy plant to test the denitration performance.The PNCR technology demonstrated excellent denitration performance with a NO_(x) emission concentration of<100 mg/Nm^(3) and high denitration efficiency of>75%at the temperature range of 800-900℃,which showed the application feasibility even on the complex and unstable industrial operating conditions.In addition,PNCR and hybrid polymer/selective non-catalytic reduction(PNCR/SNCR)technology possessed remarkable economic advantages including low investment fee and low operating cost of<10 CNY per ton of municipal solid waste(MSW)compared with selective catalytic reduction(SCR)technology.The excellent denitration performance of PNCR technology forebodes a broad industrial application prospect in the field of flue gas cleaning for waste-to-energy plants.展开更多
The purpose of this review is to explore the intersection of computational engineering and biomedical science,highlighting the transformative potential this convergence holds for innovation in healthcare and medical r...The purpose of this review is to explore the intersection of computational engineering and biomedical science,highlighting the transformative potential this convergence holds for innovation in healthcare and medical research.The review covers key topics such as computational modelling,bioinformatics,machine learning in medical diagnostics,and the integration of wearable technology for real-time health monitoring.Major findings indicate that computational models have significantly enhanced the understanding of complex biological systems,while machine learning algorithms have improved the accuracy of disease prediction and diagnosis.The synergy between bioinformatics and computational techniques has led to breakthroughs in personalized medicine,enabling more precise treatment strategies.Additionally,the integration of wearable devices with advanced computational methods has opened new avenues for continuous health monitoring and early disease detection.The review emphasizes the need for interdisciplinary collaboration to further advance this field.Future research should focus on developing more robust and scalable computational models,enhancing data integration techniques,and addressing ethical considerations related to data privacy and security.By fostering innovation at the intersection of these disciplines,the potential to revolutionize healthcare delivery and outcomes becomes increasingly attainable.展开更多
Trap-assisted charge recombination is one of the primary limitationsof restricting the performance of organic solar cells. However, effectivelyreducing the presence of traps in the photoactive layer remains challengin...Trap-assisted charge recombination is one of the primary limitationsof restricting the performance of organic solar cells. However, effectivelyreducing the presence of traps in the photoactive layer remains challenging.Herein, wide bandgap polymer donor PTzBI-dF is demonstrated as an effectivemodulator for enhancing the crystallinity of the bulk heterojunction active layerscomposed of D18 derivatives blended with Y6, leading to dense and orderedmolecular packings, and thus, improves photoluminescence quenching properties.As a result, the photovoltaic devices exhibit reduced trap-assisted charge recombinationlosses, achieving an optimized power conversion efficiency of over 19%.Besides the efficiency enhancement, the devices comprised of PTzBI-dF as athird component simultaneously attain decreased current leakage, improved chargecarrier mobilities, and suppressed bimolecular charge recombination, leading toreduced energy losses. The advanced crystalline structures induced by PTzBI-dFand its characteristics, such as well-aligned energy level, and complementaryabsorption spectra, are ascribed to the promising performance improvements.Our findings suggest that donor phase engineering is a feasible approach to tuning the molecular packings in the active layer, providingguidelines for designing effective morphology modulators for high-performance organic solar cells.展开更多
The increase in soil temperature associated with climate change has introduced considerable challenges to crop production.Split nitrogen application(SN)represents a potential strategy for improving crop nitrogen use e...The increase in soil temperature associated with climate change has introduced considerable challenges to crop production.Split nitrogen application(SN)represents a potential strategy for improving crop nitrogen use efficiency and enhancing crop stress resistance.Nevertheless,the precise interaction between soil warming(SW)and SN remains unclear.In order to ascertain the impact of SW on maize growth and whether SN can improve the tolerance of maize to SW,a two-year field experiment was conducted(2022-2023).The aim was to examine the influence of two SW ranges(MT,warming 1.40℃;HT,warming 2.75℃)and two nitrogen application methods(N1,one-time basal application of nitrogen fertilizer;N2,one third of base nitrogen fertilizer+two thirds of jointing stage supplemental nitrogen fertilizer)on maize root growth,photosynthetic characteristics,nitrogen use efficiency,and yield.The results demonstrated that SW impeded root growth and precipitated the premature aging of maize leaves following anthesis,particularly in the HT,which led to a notable reduction in maize yield.In comparison to N1,SN has been shown to increase root length density by 8.54%,root bleeding rate by 8.57%,and enhance root distribution ratio in the middle soil layers(20-60 cm).The interaction between SW and SN had a notable impact on maize growth and yield.The SN improved the absorption and utilization efficiency of nitrogen by promoting root development and downward canopy growth,thus improving the tolerance of maize to SW at the later stage of growth.In particular,the N2HT resulted in a 14.51%increase in the photosynthetic rate,a 18.58%increase in nitrogen absorption efficiency,and a 18.32%increase in maize yield compared with N1HT.It can be posited that the SN represents a viable nitrogen management measure with the potential to enhance maize tolerance to soil high-temperature stress.展开更多
Conventional superconducting nanowire single-photon detectors(SNSPDs)have been typically limited in their applications due to their size,weight,and power consumption,which confine their use to laboratory settings.Howe...Conventional superconducting nanowire single-photon detectors(SNSPDs)have been typically limited in their applications due to their size,weight,and power consumption,which confine their use to laboratory settings.However,with the rapid development of remote imaging,sensing technologies,and long-range quantum communication with fewer topographical constraints,the demand for high-efficiency single-photon detectors integrated with avionic platforms is rapidly growing.We herein designed and manufactured the first drone-based SNSPD system with a system detection efficiency(SDE)as high as 91.8%.This drone-based system incorporates high-performance NbTiN SNSPDs,a self-developed miniature liquid helium dewar,and custom-built integrated electrical setups,making it capable of being launched in complex topographical conditions.Such a drone-based SNSPD system may open the use of SNSPDs for applications that demand high SDE in complex environments.展开更多
In this paper,a wideband true time delay line for X-band is designed to overcome the beam dispersion problem in a high-resolution spaceborne synthetic aperture radar phased array antenna system.The delay line loads th...In this paper,a wideband true time delay line for X-band is designed to overcome the beam dispersion problem in a high-resolution spaceborne synthetic aperture radar phased array antenna system.The delay line loads the electromagnetic bandgap structure on the upper surface of the substrate integrated waveguide.This is equivalent to including an additional inductance-capacitance for energy storage,which realizes the slow-wave effect.A microstrip line-SIW tapered transition structure is introduced to achieve a low loss and a large bandwidth.In the frequency band between 8-12 GHz,the measured results show that the delay multiplier of the delay line reaches 4 times,i.e.,delay line’s delay time is 4 times larger than 50Ωmicrostrip line with same length.Furthermore,the delay fluctuation,i.e.,the difference between the maximum and minimum delay as a percentage of the standard delay is only 2.5%,the insertion loss is less than-2.5 dB,and the return loss is less than-15 dB.Compared with the existing delay lines,the proposed delay line has the advantages of high delay efficiency,low delay error,wide bandwidth and low loss,which has good practical value and application prospects.展开更多
The Literary Lab at Stanford University is one of the birthplaces of digital humanities and has maintained significant influence in this field over the years.Professor Hui Haifeng has been engaged in research on digit...The Literary Lab at Stanford University is one of the birthplaces of digital humanities and has maintained significant influence in this field over the years.Professor Hui Haifeng has been engaged in research on digital humanities and computational criticism in recent years.During his visiting scholarship at Stanford University,he participated in the activities of the Literary Lab.Taking this opportunity,he interviewed Professor Mark Algee-Hewitt,the director of the Literary Lab,discussing important topics such as the current state and reception of DH(digital humanities)in the English Department,the operations of the Literary Lab,and the landscape of computational criticism.Mark Algee-Hewitt's research focuses on the eighteenth and early nineteenth centuries in England and Germany and seeks to combine literary criticism with digital and quantitative analyses of literary texts.In particular,he is interested in the history of aesthetic theory and the development and transmission of aesthetic and philosophical concepts during the Enlightenment and Romantic periods.He is also interested in the relationship between aesthetic theory and the poetry of the long eighteenth century.Although his primary background is English literature,he also has a degree in computer science.He believes that the influence of digital humanities within the humanities disciplines is growing increasingly significant.This impact is evident in both the attraction and assistance it offers to students,as well as in the new interpretations it brings to traditional literary studies.He argues that the key to effectively integrating digital humanities into the English Department is to focus on literary research questions,exploring how digital tools can raise new questions or provide new insights into traditional research.展开更多
In order to accurately forecast the main engine fuel consumption and reduce the Energy Efficiency Operational Indicator(EEOI)of merchant ships in polar ice areas,the energy transfer relationship between ship-machine-p...In order to accurately forecast the main engine fuel consumption and reduce the Energy Efficiency Operational Indicator(EEOI)of merchant ships in polar ice areas,the energy transfer relationship between ship-machine-propeller is studied by analyzing the complex force situation during ship navigation and building a MATLAB/Simulink simulation platform based on multi-environmental resistance,propeller efficiency,main engine power,fuel consumption,fuel consumption rate and EEOI calculation module.Considering the environmental factors of wind,wave and ice,the route is divided into sections,the calculation of main engine power,main engine fuel consumption and EEOI for each section is completed,and the speed design is optimized based on the simulation model for each section.Under the requirements of the voyage plan,the optimization results show that the energy efficiency operation index of the whole route is reduced by 3.114%and the fuel consumption is reduced by 9.17 t.展开更多
This study reviewed developments in provider utilization related to health care in the metropolitan area of the Syracuse hospitals between the twentieth century and the twenty first century with respect to major hospi...This study reviewed developments in provider utilization related to health care in the metropolitan area of the Syracuse hospitals between the twentieth century and the twenty first century with respect to major hospital services. In this study, a decline in the utilization of inpatient hospitals developed between 2020 and 2022. During this period, use of additional outpatient services such as ambulatory surgery, individual practitioners, outside hospitals, and the use of hospital emergency departments developed in the community. The study data demonstrated that between 2020 and 2022, the numbers of discharges from the combined hospitals declined for both adult medicine and adult surgery. Inpatient discharges declined by 2730 patients for adult medicine and 1961 patients for adult surgery. The data also demonstrated that between 2022 and 2024, the numbers of discharges increased by 1998 discharges for adult medicine and by 229 for adult surgery. As followup to this study, health care providers and payors should review approaches to efficiency in their communities and evaluate their impact on health care efficiency.展开更多
Ports are crucial to the economy of many nations;thus, numerous studies have been conducted on port efficiency and productivity. This study analyses the efficiency and productivity of some major global ports namely, P...Ports are crucial to the economy of many nations;thus, numerous studies have been conducted on port efficiency and productivity. This study analyses the efficiency and productivity of some major global ports namely, Port of Singapore, Rotterdam, Antwerp and Durban. The main objectives of this study are to determine the level of operational efficiency of the mentioned ports, measure and evaluate the ports’ productivity changes and lastly to investigate the factors influencing the productivity changes of the ports studied. To achieve these objectives, Data Envelopment Analysis (DEA-BCC) model was used to determine the technical and operational efficiencies of the ports and Malmquist productivity index was employed to calculate the various productivity levels. The results of the study can guide stakeholders to formulate their operational strategies for port efficiency and productivity. The study also has policy suggestions that are uniquely targeted to Africa’s issues and potential.展开更多
This study reviewed a combination of health care programs in the metropolitan area of Syracuse, New York. They were designed to improve care, however a major purpose was to support efficiency. The study described a nu...This study reviewed a combination of health care programs in the metropolitan area of Syracuse, New York. They were designed to improve care, however a major purpose was to support efficiency. The study described a number of individual programs that were developed in order to improve the quality and the efficiency of care. These programs were implemented by a combination of local providers and payors. They included the development of outpatient services such as ambulatory surgery, as well as preventive care, case management, telemedicine, and mental health. The impact of these programs was a combination of these services, rather than individual efforts. The impact of these efforts was the product of a range of individual services, especially care management. Additional efforts should make it possible to extend these efforts among providers and payors in the Syracuse area. This approach should make it possible to extend the impact of health care efficiency further.展开更多
This work focuses on maximizing the minimum user’s security energy efficiency(SEE)in an unmanned aerial vehicle-mounted reconfigurable intelligent surface(UAV-RIS)enhanced short-packet communication(SPC)system.The ba...This work focuses on maximizing the minimum user’s security energy efficiency(SEE)in an unmanned aerial vehicle-mounted reconfigurable intelligent surface(UAV-RIS)enhanced short-packet communication(SPC)system.The base station(BS)provides short packet services to ground users using the non-orthogonal multiple access(NOMA)protocol through UAV-RIS,while preventing eavesdropper attacks.To optimize SEE,a joint optimization is performed concerning power allocation,UAV position,decoding order,and RIS phase shifts.An iterative algorithm based on block coordinate descent is proposed for mixed-integer non-convex SEE optimization problem.The original problem is decomposed into three sub-problems,solved alternately using successive convex approximation(SCA),quadratic transformation,penalty function,and semi-definite programming(SDP).Simulation results demonstrate the performance of the UAV-RIS-enhanced short-packet system under different parameters and verify the algorithm’s convergence.Compared to benchmark schemes such as orthogonal multiple access,long packet communication,and sum SEE,the proposed UAV-RIS-enhanced short-packet scheme achieves the higher minimum user’s SEE.展开更多
With the objective of investigating the basis of phosphorus(P)utilization efficiency(PUE),physiological and morphological traits,two P-efficient and two P-inefficient rapeseed(Brassica napus L.)cultivars were compared...With the objective of investigating the basis of phosphorus(P)utilization efficiency(PUE),physiological and morphological traits,two P-efficient and two P-inefficient rapeseed(Brassica napus L.)cultivars were compared at the seedling stage.P-efficient cultivars showed root morphological adaptation,high P uptake activity,and greater phospholipid degradation under low P stress.Improving root morphological adaptation and reducing lipid-P allocation could allow increasing PUE in rapeseed seedlings.展开更多
文摘The growing need for sustainable energy solutions,driven by rising energy shortages,environmental concerns,and the depletion of conventional energy sources,has led to a significant focus on renewable energy.Solar energy,among the various renewable sources,is particularly appealing due to its abundant availability.However,the efficiency of commercial solar photovoltaic(PV)modules is hindered by several factors,notably their conversion efficiency,which averages around 19%.This efficiency can further decline to 10%–16%due to temperature increases during peak sunlight hours.This study investigates the cooling of PV modules by applying water to their front surface through Computational fluid dynamics(CFD).The study aimed to determine the optimal conditions for cooling the PV module by analyzing the interplay between water film thickness,Reynolds number,and their effects on temperature reduction and heat transfer.The CFD analysis revealed that the most effective cooling condition occurred with a 5 mm thick water film and a Reynolds number of 10.These specific parameters were found to maximize the heat transfer and temperature reduction efficiency.This finding is crucial for the development of practical and efficient cooling systems for PV modules,potentially leading to improved performance and longevity of solar panels.Alternative cooling fluids or advanced cooling techniques that might offer even better efficiency or practical benefits.
基金supported by the National Natural Science Foundation of China(Grant Nos.11902085 and 11832009)the Science and Technology Association Young Scientific and Technological Talents Support Project of Guangzhou City(Grant No.SKX20210304)the Natural Science Foundation of Guangdong Province(Grant No.2021Al515010320).
文摘Huge calculation burden and difficulty in convergence are the two central conundrums of nonlinear topology optimization(NTO).To this end,a multi-resolution nonlinear topology optimization(MR-NTO)method is proposed based on the multiresolution design strategy(MRDS)and the additive hyperelasticity technique(AHT),taking into account the geometric nonlinearity and material nonlinearity.The MR-NTO strategy is established in the framework of the solid isotropic material with penalization(SIMP)method,while the Neo-Hookean hyperelastic material model characterizes the material nonlinearity.The coarse analysis grid is employed for finite element(FE)calculation,and the fine material grid is applied to describe the material configuration.To alleviate the convergence problem and reduce sensitivity calculation complexity,the software ANSYS coupled with AHT is utilized to perform the nonlinear FE calculation.A strategy for redistributing strain energy is proposed during the sensitivity analysis,i.e.,transforming the strain energy of the analysis element into that of the material element,including Neo-Hooken and second-order Yeoh material.Numerical examples highlight three distinct advantages of the proposed method,i.e.,it can(1)significantly improve the computational efficiency,(2)make up for the shortcoming that NTO based on AHT may have difficulty in convergence when solving the NTO problem,especially for 3D problems,(3)successfully cope with high-resolution 3D complex NTO problems on a personal computer.
基金Project supported by the National Natural Science Foundation of China (Grant No.60876027)the National Science Foundation for Distinguished Young Scholars of China (Grant No.60925015)+1 种基金the National Basic Research Program of China (Grant No.2011CBA00600)the Fundamental Research Project of Shenzhen Science & Technology Foundation,China (Grant No.JC200903160353A)
文摘As a connection between the process and the circuit design, the device model is greatly desired for emerging devices, such as the double-gate MOSFET. Time efficiency is one of the most important requirements for device modeling. In this paper, an improvement to the computational efficiency of the drain current model for double-gate MOSFETs is extended, and different calculation methods are compared and discussed. The results show that the calculation speed of the improved model is substantially enhanced. A two-dimensional device simulation is performed to verify the improved model. Furthermore, the model is implemented into the HSPICE circuit simulator in Verilog-A for practical application.
基金supported by the National Natural Science Foundation of China(Grant Nos.11974154,and 12304278)the Taishan Scholars Special Funding for Construction Projects(Grant No.tstp20230622)+1 种基金the Natural Science Foundation of Shandong Province(Grant Nos.ZR2022MA004,ZR2023QA127,and ZR2024QA121)the Special Foundation of Yantai for Leading Talents above Provincial Level。
文摘The four-decade quest for synthesizing ambient-stable polymeric nitrogen,a promising high-energy-density material,remains an unsolved challenge in materials science.We develop a multi-stage computational strategy employing density functional tight-binding-based rapid screening combined with density functional theory refinement and global structure searching,effectively bridging computational efficiency with quantum accuracy.This integrated approach identifies four novel polymeric nitrogen phases(Fddd,P3221,I4m2,and𝑃P6522)that are thermodynamically stable at ambient pressure.Remarkably,the helical𝑃6522 configuration demonstrates exceptional thermal resilience up to 1500 K,representing a predicted polymeric nitrogen structure that maintains stability under both atmospheric pressure and high-temperature extremes.Our methodology establishes a paradigm-shifting framework for the accelerated discovery of metastable energetic materials,resolving critical bottlenecks in theoretical predictions while providing experimentally actionable targets for polymeric nitrogen synthesis.
基金National Nonprofit Institute Research Grant of CAF,No.CAFYBB2018ZA004,No.CAFYBB2023ZA009Fengyun Application Pioneering Project,No.FY-APP-ZX-2023.02。
文摘Water use efficiency(WUE),as a pivotal indicator of the coupling degree within the carbon–water cycle of ecosystems,holds considerable importance in assessment of the carbon–water balance within terrestrial ecosystems.However,in the context of global warming,WUE evolution and its primary drivers on the Tibetan Plateau remain unclear.This study employed the ensemble empirical mode decomposition method and the random forest algorithm to decipher the nonlinear trends and drivers of WUE on the Tibetan Plateau in 2001–2020.Results indicated an annual mean WUE of 0.8088 gC/mm·m^(2)across the plateau,with a spatial gradient reflecting decrease from the southeast toward the northwest.Areas manifesting monotonous trends of increase or decrease in WUE accounted for 23.64%and 9.69%of the total,respectively.Remarkably,66.67%of the region exhibited trend reversals,i.e.,39.94%of the area of the Tibetan Plateau showed transition from a trend of increase to a trend of decrease,and 26.73%of the area demonstrated a shift from a trend of decrease to a trend of increase.Environmental factors accounted for 70.79%of the variability in WUE.The leaf area index and temperature served as the major driving forces of WUE variation.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20202 and 52275477).
文摘Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling.However,the conventional trochoidal tool path presents challenges such as lower machining efficiency and longer machining time due to its time-varying cutter-workpiece engagement angle and a high percentage of non-cutting tool paths.To address these issues,this paper introduces a parameter-variant trochoidal-like(PVTR)tool path planning method for chatter-free and high-efficiency milling.This method ensures a constant engagement angle for each tool path period by adjusting the trochoidal radius and step.Initially,the nonlinear equation for the PVTR toolpath is established.Then,a segmented recurrence method is proposed to plan tool paths based on the desired engagement angle.The impact of trochoidal tool path parameters on the engagement angle is analyzed and coupled this information with the milling stability model based on spindle speed and engagement angle to determine the desired engagement angle throughout the machining process.Finally,several experimental tests are carried out using the bull-nose end mill to validate the feasibility and effectiveness of the proposed method.
基金financially supported by a National Research Foundation of Korea(NRF)grant funded by the Korean government(No.2016R1A3B1908249,RS202400407199).
文摘Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal conductivities of phase-change materials(PCMs)promote Joule heating dissi-pation.Repeated phase transitions also induce long-range atomic diffusion,limiting the durability.To address these challenges,phase-change heterostructure(PCH)devices that incorporate confinement sub-layers based on transition-metal dichalcogenide materials have been developed.In this study,we engi-neered a PCH device by integrating HfTe_(2),which has low thermal conductivity and excellent stability,into the PCM to realize PCRAM with enhanced thermal efficiency and structural stability.HEAT sim-ulations were conducted to validate the superior heat confinement in the programming region of the HfTe_(2)-based PCH device.Moreover,electrical measurements of the device demonstrated its outstanding performance,which was characterized by a low RESET current(∼1.6 mA),stable two-order ON/OFF ratio,and exceptional cycling endurance(∼2×10^(7)).The structural integrity of the HfTe_(2)confinement sub-layer was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy.The material properties,including electrical conductivity,cohesive energy,and electronegativity,substantiated these findings.Collectively,these results revealed that the HfTe_(2)-based PCH device can achieve significant improvements in performance and reliability compared with conventional PCRAM devices.
基金supported by the National Natural Science Foundation of China(No.92367107)。
文摘Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration efficiency,complex denitration system,and high investment and operating cost.Here we put forward a novel polymer non-catalytic reduction(PNCR)technology that utilized a new type of polymer agent to remove NO_(x),and the proposed PNCR technology was applied to the existing waste-to-energy plant to test the denitration performance.The PNCR technology demonstrated excellent denitration performance with a NO_(x) emission concentration of<100 mg/Nm^(3) and high denitration efficiency of>75%at the temperature range of 800-900℃,which showed the application feasibility even on the complex and unstable industrial operating conditions.In addition,PNCR and hybrid polymer/selective non-catalytic reduction(PNCR/SNCR)technology possessed remarkable economic advantages including low investment fee and low operating cost of<10 CNY per ton of municipal solid waste(MSW)compared with selective catalytic reduction(SCR)technology.The excellent denitration performance of PNCR technology forebodes a broad industrial application prospect in the field of flue gas cleaning for waste-to-energy plants.
文摘The purpose of this review is to explore the intersection of computational engineering and biomedical science,highlighting the transformative potential this convergence holds for innovation in healthcare and medical research.The review covers key topics such as computational modelling,bioinformatics,machine learning in medical diagnostics,and the integration of wearable technology for real-time health monitoring.Major findings indicate that computational models have significantly enhanced the understanding of complex biological systems,while machine learning algorithms have improved the accuracy of disease prediction and diagnosis.The synergy between bioinformatics and computational techniques has led to breakthroughs in personalized medicine,enabling more precise treatment strategies.Additionally,the integration of wearable devices with advanced computational methods has opened new avenues for continuous health monitoring and early disease detection.The review emphasizes the need for interdisciplinary collaboration to further advance this field.Future research should focus on developing more robust and scalable computational models,enhancing data integration techniques,and addressing ethical considerations related to data privacy and security.By fostering innovation at the intersection of these disciplines,the potential to revolutionize healthcare delivery and outcomes becomes increasingly attainable.
基金support from the National Natural Science Foundation of China(62275057)the Guangxi Natural Science Foundation(2023GXNSFFA026004 and 2022GXNSFDA035066)+2 种基金the Innovation Project of Guangxi Graduate Education(YCBZ2024034)Natural Science Foundation of Ningbo under grant(2022J149)Natural Science Foundation of Ningbo under grant(2022A-230-G)
文摘Trap-assisted charge recombination is one of the primary limitationsof restricting the performance of organic solar cells. However, effectivelyreducing the presence of traps in the photoactive layer remains challenging.Herein, wide bandgap polymer donor PTzBI-dF is demonstrated as an effectivemodulator for enhancing the crystallinity of the bulk heterojunction active layerscomposed of D18 derivatives blended with Y6, leading to dense and orderedmolecular packings, and thus, improves photoluminescence quenching properties.As a result, the photovoltaic devices exhibit reduced trap-assisted charge recombinationlosses, achieving an optimized power conversion efficiency of over 19%.Besides the efficiency enhancement, the devices comprised of PTzBI-dF as athird component simultaneously attain decreased current leakage, improved chargecarrier mobilities, and suppressed bimolecular charge recombination, leading toreduced energy losses. The advanced crystalline structures induced by PTzBI-dFand its characteristics, such as well-aligned energy level, and complementaryabsorption spectra, are ascribed to the promising performance improvements.Our findings suggest that donor phase engineering is a feasible approach to tuning the molecular packings in the active layer, providingguidelines for designing effective morphology modulators for high-performance organic solar cells.
基金supported by the Natural Science Fund of China(31771724)the Key Research and Development Project of Shaanxi Province(2024NC-ZDCYL-01-10).
文摘The increase in soil temperature associated with climate change has introduced considerable challenges to crop production.Split nitrogen application(SN)represents a potential strategy for improving crop nitrogen use efficiency and enhancing crop stress resistance.Nevertheless,the precise interaction between soil warming(SW)and SN remains unclear.In order to ascertain the impact of SW on maize growth and whether SN can improve the tolerance of maize to SW,a two-year field experiment was conducted(2022-2023).The aim was to examine the influence of two SW ranges(MT,warming 1.40℃;HT,warming 2.75℃)and two nitrogen application methods(N1,one-time basal application of nitrogen fertilizer;N2,one third of base nitrogen fertilizer+two thirds of jointing stage supplemental nitrogen fertilizer)on maize root growth,photosynthetic characteristics,nitrogen use efficiency,and yield.The results demonstrated that SW impeded root growth and precipitated the premature aging of maize leaves following anthesis,particularly in the HT,which led to a notable reduction in maize yield.In comparison to N1,SN has been shown to increase root length density by 8.54%,root bleeding rate by 8.57%,and enhance root distribution ratio in the middle soil layers(20-60 cm).The interaction between SW and SN had a notable impact on maize growth and yield.The SN improved the absorption and utilization efficiency of nitrogen by promoting root development and downward canopy growth,thus improving the tolerance of maize to SW at the later stage of growth.In particular,the N2HT resulted in a 14.51%increase in the photosynthetic rate,a 18.58%increase in nitrogen absorption efficiency,and a 18.32%increase in maize yield compared with N1HT.It can be posited that the SN represents a viable nitrogen management measure with the potential to enhance maize tolerance to soil high-temperature stress.
基金the Innovation Program for Quantum Science and Technology(Grant No.2023ZD0300100)the National Key Research and Development Program of China(Grant Nos.2023YFB3809600 and 2023YFC3007801)+1 种基金the National Natural Science Foundation of China(Grant Nos.62301543 and U24A20320)the Shanghai Sailing Program(Grant No.21YF1455700).
文摘Conventional superconducting nanowire single-photon detectors(SNSPDs)have been typically limited in their applications due to their size,weight,and power consumption,which confine their use to laboratory settings.However,with the rapid development of remote imaging,sensing technologies,and long-range quantum communication with fewer topographical constraints,the demand for high-efficiency single-photon detectors integrated with avionic platforms is rapidly growing.We herein designed and manufactured the first drone-based SNSPD system with a system detection efficiency(SDE)as high as 91.8%.This drone-based system incorporates high-performance NbTiN SNSPDs,a self-developed miniature liquid helium dewar,and custom-built integrated electrical setups,making it capable of being launched in complex topographical conditions.Such a drone-based SNSPD system may open the use of SNSPDs for applications that demand high SDE in complex environments.
基金Supported by the National Natural Science Foundation of China(61971401)。
文摘In this paper,a wideband true time delay line for X-band is designed to overcome the beam dispersion problem in a high-resolution spaceborne synthetic aperture radar phased array antenna system.The delay line loads the electromagnetic bandgap structure on the upper surface of the substrate integrated waveguide.This is equivalent to including an additional inductance-capacitance for energy storage,which realizes the slow-wave effect.A microstrip line-SIW tapered transition structure is introduced to achieve a low loss and a large bandwidth.In the frequency band between 8-12 GHz,the measured results show that the delay multiplier of the delay line reaches 4 times,i.e.,delay line’s delay time is 4 times larger than 50Ωmicrostrip line with same length.Furthermore,the delay fluctuation,i.e.,the difference between the maximum and minimum delay as a percentage of the standard delay is only 2.5%,the insertion loss is less than-2.5 dB,and the return loss is less than-15 dB.Compared with the existing delay lines,the proposed delay line has the advantages of high delay efficiency,low delay error,wide bandwidth and low loss,which has good practical value and application prospects.
文摘The Literary Lab at Stanford University is one of the birthplaces of digital humanities and has maintained significant influence in this field over the years.Professor Hui Haifeng has been engaged in research on digital humanities and computational criticism in recent years.During his visiting scholarship at Stanford University,he participated in the activities of the Literary Lab.Taking this opportunity,he interviewed Professor Mark Algee-Hewitt,the director of the Literary Lab,discussing important topics such as the current state and reception of DH(digital humanities)in the English Department,the operations of the Literary Lab,and the landscape of computational criticism.Mark Algee-Hewitt's research focuses on the eighteenth and early nineteenth centuries in England and Germany and seeks to combine literary criticism with digital and quantitative analyses of literary texts.In particular,he is interested in the history of aesthetic theory and the development and transmission of aesthetic and philosophical concepts during the Enlightenment and Romantic periods.He is also interested in the relationship between aesthetic theory and the poetry of the long eighteenth century.Although his primary background is English literature,he also has a degree in computer science.He believes that the influence of digital humanities within the humanities disciplines is growing increasingly significant.This impact is evident in both the attraction and assistance it offers to students,as well as in the new interpretations it brings to traditional literary studies.He argues that the key to effectively integrating digital humanities into the English Department is to focus on literary research questions,exploring how digital tools can raise new questions or provide new insights into traditional research.
文摘In order to accurately forecast the main engine fuel consumption and reduce the Energy Efficiency Operational Indicator(EEOI)of merchant ships in polar ice areas,the energy transfer relationship between ship-machine-propeller is studied by analyzing the complex force situation during ship navigation and building a MATLAB/Simulink simulation platform based on multi-environmental resistance,propeller efficiency,main engine power,fuel consumption,fuel consumption rate and EEOI calculation module.Considering the environmental factors of wind,wave and ice,the route is divided into sections,the calculation of main engine power,main engine fuel consumption and EEOI for each section is completed,and the speed design is optimized based on the simulation model for each section.Under the requirements of the voyage plan,the optimization results show that the energy efficiency operation index of the whole route is reduced by 3.114%and the fuel consumption is reduced by 9.17 t.
文摘This study reviewed developments in provider utilization related to health care in the metropolitan area of the Syracuse hospitals between the twentieth century and the twenty first century with respect to major hospital services. In this study, a decline in the utilization of inpatient hospitals developed between 2020 and 2022. During this period, use of additional outpatient services such as ambulatory surgery, individual practitioners, outside hospitals, and the use of hospital emergency departments developed in the community. The study data demonstrated that between 2020 and 2022, the numbers of discharges from the combined hospitals declined for both adult medicine and adult surgery. Inpatient discharges declined by 2730 patients for adult medicine and 1961 patients for adult surgery. The data also demonstrated that between 2022 and 2024, the numbers of discharges increased by 1998 discharges for adult medicine and by 229 for adult surgery. As followup to this study, health care providers and payors should review approaches to efficiency in their communities and evaluate their impact on health care efficiency.
文摘Ports are crucial to the economy of many nations;thus, numerous studies have been conducted on port efficiency and productivity. This study analyses the efficiency and productivity of some major global ports namely, Port of Singapore, Rotterdam, Antwerp and Durban. The main objectives of this study are to determine the level of operational efficiency of the mentioned ports, measure and evaluate the ports’ productivity changes and lastly to investigate the factors influencing the productivity changes of the ports studied. To achieve these objectives, Data Envelopment Analysis (DEA-BCC) model was used to determine the technical and operational efficiencies of the ports and Malmquist productivity index was employed to calculate the various productivity levels. The results of the study can guide stakeholders to formulate their operational strategies for port efficiency and productivity. The study also has policy suggestions that are uniquely targeted to Africa’s issues and potential.
文摘This study reviewed a combination of health care programs in the metropolitan area of Syracuse, New York. They were designed to improve care, however a major purpose was to support efficiency. The study described a number of individual programs that were developed in order to improve the quality and the efficiency of care. These programs were implemented by a combination of local providers and payors. They included the development of outpatient services such as ambulatory surgery, as well as preventive care, case management, telemedicine, and mental health. The impact of these programs was a combination of these services, rather than individual efforts. The impact of these efforts was the product of a range of individual services, especially care management. Additional efforts should make it possible to extend these efforts among providers and payors in the Syracuse area. This approach should make it possible to extend the impact of health care efficiency further.
基金co-supported by the National Natural Science Foundation of China(Nos.U23A20279,62271094)the National Key R&D Program of China(No.SQ2023YFB2500024)+2 种基金the Science Foundation for Youths of Natural Science Foundation of Sichuan Provincial,China(No.2022NSFSC0936)the China Postdoctoral Science Foundation(No.2022M720666)the Open Fund of Key Laboratory of Big Data Intelligent Computing,Chongqing University of Posts and Telecommunications,China(No.BDIC-2023-B-002).
文摘This work focuses on maximizing the minimum user’s security energy efficiency(SEE)in an unmanned aerial vehicle-mounted reconfigurable intelligent surface(UAV-RIS)enhanced short-packet communication(SPC)system.The base station(BS)provides short packet services to ground users using the non-orthogonal multiple access(NOMA)protocol through UAV-RIS,while preventing eavesdropper attacks.To optimize SEE,a joint optimization is performed concerning power allocation,UAV position,decoding order,and RIS phase shifts.An iterative algorithm based on block coordinate descent is proposed for mixed-integer non-convex SEE optimization problem.The original problem is decomposed into three sub-problems,solved alternately using successive convex approximation(SCA),quadratic transformation,penalty function,and semi-definite programming(SDP).Simulation results demonstrate the performance of the UAV-RIS-enhanced short-packet system under different parameters and verify the algorithm’s convergence.Compared to benchmark schemes such as orthogonal multiple access,long packet communication,and sum SEE,the proposed UAV-RIS-enhanced short-packet scheme achieves the higher minimum user’s SEE.
基金supported by the National Key Research and Development Program of China(2024YFD2301200)National Nature Science Foundation of China(32172662).
文摘With the objective of investigating the basis of phosphorus(P)utilization efficiency(PUE),physiological and morphological traits,two P-efficient and two P-inefficient rapeseed(Brassica napus L.)cultivars were compared at the seedling stage.P-efficient cultivars showed root morphological adaptation,high P uptake activity,and greater phospholipid degradation under low P stress.Improving root morphological adaptation and reducing lipid-P allocation could allow increasing PUE in rapeseed seedlings.
