Hybrid nanofluids have gained significant attention for their superior thermal and rheological characteristics,offering immense potential in energy conversion,biomedical transport,and electromagnetic flow control syst...Hybrid nanofluids have gained significant attention for their superior thermal and rheological characteristics,offering immense potential in energy conversion,biomedical transport,and electromagnetic flow control systems.Understanding their dynamic behavior under coupled magnetic,rotational,and reactive effects is crucial for the development of efficient thermal management technologies.This study develops a neuro-fuzzy computational framework to examine the dynamics of a reactive Cu–TiO_(2)–H_(2)Ohybrid nanofluid flowing through a squarely elevated Riga tunnel.The governing model incorporates Hall and ion-slip effects,thermal radiation,and first-order chemical reactions under ramped thermo-solutal boundary conditions and rotational electromagnetic forces.Closed-form analytical solutions are derived via the Laplace transform method to describe the transient velocity,temperature,and concentration fields.To complement and validate the analytical model,an artificial neural network(ANN)optimized using the Levenberg–Marquardt backpropagation algorithm(ANN-LMBPA)is trained on datasets generated in Mathematica.Regression and error analyses confirm the model’s predictive robustness,with mean squared errors ranging between 10^(-4) and 10^(-9).In addition,an Adaptive Neuro-Fuzzy Inference System(ANFIS)is developed to estimate the heat transfer rate(HTR),achieving aminimal RMSE of 0.011012 for the heat transfer coefficient(HTC).The findings reveal that rotational motion and Hall–ion slip effects suppress primary velocity but enhance secondary flow,while the modified Hartmann number(Lorentz force)accelerates both components.Thermal radiation increases fluid temperature,whereas higher Schmidt numbers and reaction rates diminish solute concentration.The HTR decreases with increasing radiation and nanoparticle volume fraction,while the mass transfer rate(MTR)improves under stronger chemical reactivity.Overall,the proposed hybrid analytical–AI framework demonstrates high accuracy and efficiency,offering valuable insights for the design and optimization of electromagnetic nanofluid systems in advanced thermal and process engineering applications.展开更多
Radiation effect on the natural convection flow of an optically thin viscous incompressible fluid near a vertical plate with ramped wall temperature in a porous medium has been studied. The exact solution of momentum ...Radiation effect on the natural convection flow of an optically thin viscous incompressible fluid near a vertical plate with ramped wall temperature in a porous medium has been studied. The exact solution of momentum and energy equations is obtained by the use of Laplace transform technique. The variations in fluid velocity and temperature are shown graphically whereas the numerical values of shear stress and the rate of heat transfer at the wall are presented in tabular form for various values of flow parameters. The results show that the fluid velocity increases with increase in Grashof number, Darcy number and time parameters whereas the fluid velocity decreases with increase in the radiation parameter and Prandtl number for ramped temperature as well as isothermal wall temperature. It is found that an increase in radiation parameter leads to rise the temperature for both ramped wall temperature as well as isothermal wall temperature. Further, it is found that an increase in Prandtl number leads to fall the temperature for both ramped wall temperature as well as isothermal wall temperature. The shear stress at the wall decreases with increases in either Prandtl number or porosity parameter while the result shows reverse in the case of radiation parameter. Finally, the rate of heat transfer is increased with increases in the radiation parameter for both ramped wall temperature as well as isothermal wall temperature.展开更多
An exact analysis of the flow of an incompressible viscous fluid past an infinite vertical plate is conducted taking into account the presence of foreign mass or constant mass flux and ramped wall temperature. The dim...An exact analysis of the flow of an incompressible viscous fluid past an infinite vertical plate is conducted taking into account the presence of foreign mass or constant mass flux and ramped wall temperature. The dimensionless governing coupled linear partial differential equations are solved using the Laplace transform technique. Two different solutions for the fluid velocity are obtained–one valid for the fluids of Schmidt numbers different from unity, and the other for which the Schmidt number is unity. The effects of Prandtl number (Pr), Schmidt number (Sc), time (t) and mass to thermal buoyancy ratio parameter (N) for both aiding and opposing buoyancy effects on the velocity and skin-friction are studied. Also, the heat and mass transfer effects on the flow near a ramped temperature plate have been compared with the flow near a plate with constant temperature.展开更多
The effect of radiation on the unsteady natural convection flow past an infinite vertical plate is presented, wherein the plate temperature is a ramped one. The fluid considered here is a gray, absorbing/emitting but ...The effect of radiation on the unsteady natural convection flow past an infinite vertical plate is presented, wherein the plate temperature is a ramped one. The fluid considered here is a gray, absorbing/emitting but a non-scattering medium. The influence of the various parameters entering into the problem on the velocity field, temperature field, skin friction and Nusselt number is studied.展开更多
This study considers a theoretical analysis of natural convection flow of heat generating/absorbing fluid near an infinite vertical plate with ramped temperature. It is assumed that the bounding plate has a ramped tem...This study considers a theoretical analysis of natural convection flow of heat generating/absorbing fluid near an infinite vertical plate with ramped temperature. It is assumed that the bounding plate has a ramped temperature profile. Exact solutions of energy and momentum equations are obtained using the Laplacetransform techniques. Solutions are obtained for different values of the Prandtl number (Pr) and the heat sink parameter (S). Results of the ramped and isothermal temperature and velocity as well as Nusselt number and skin friction have been compared and presented with the help of graphs.展开更多
The present paper is concerned with the study of flow,heat and mass transfer characteristics in the unsteady natural convective magneto hydrodynamics Casson fluid flow past over an oscillating vertical plate.The gover...The present paper is concerned with the study of flow,heat and mass transfer characteristics in the unsteady natural convective magneto hydrodynamics Casson fluid flow past over an oscillating vertical plate.The governing partial differential equations are solved analytically using Laplace transform technique and numerically using Matlab software.Expressions of skin friction,Nusselt number and Sherwood number are obtained.The features of the fluid flow,heat and mass transfer characteristics are analyzed by plotting graphs and the physical aspects are discussed in detail.展开更多
本研究旨在深入探索RAMP(Range of Motion,Activation,Mobility,Potentiation)热身系统在初中体育教学中的应用效果,通过一个学期的对比实验,评估其对初中生体能水平、运动技能掌握、运动损伤预防以及体育课堂参与度的综合影响。研究选...本研究旨在深入探索RAMP(Range of Motion,Activation,Mobility,Potentiation)热身系统在初中体育教学中的应用效果,通过一个学期的对比实验,评估其对初中生体能水平、运动技能掌握、运动损伤预防以及体育课堂参与度的综合影响。研究选取某初中二年级2个班级共80名学生作为研究对象,采用随机对照试验设计,实验组采用RAMP热身系统,对照组沿用传统热身方式。结果表明,RAMP热身系统在提升体能、促进技能掌握、降低运动损伤风险及提高课堂参与度方面均表现出显著优势。本研究为初中体育教学提供了科学依据,建议推广RAMP热身系统以优化体育课堂结构,促进学生全面发展。展开更多
[目的]比较关节镜下缝合钩和Fast-fix缝合Ⅳ型半月板Ramp区损伤的临床疗效。[方法]回顾性分析2016年1月—2020年10月45例前交叉韧带(anterior cruciate ligament, ACL)损伤合并Ⅳ型半月板Ramp损伤患者的临床资料。所有患者均取自体腘绳...[目的]比较关节镜下缝合钩和Fast-fix缝合Ⅳ型半月板Ramp区损伤的临床疗效。[方法]回顾性分析2016年1月—2020年10月45例前交叉韧带(anterior cruciate ligament, ACL)损伤合并Ⅳ型半月板Ramp损伤患者的临床资料。所有患者均取自体腘绳肌腱行ACL重建,依据术前医患沟通结果,21例应用缝合钩缝合Ramp损伤,24例应用Fast-fix缝合。对比患者围手术期、随访及影像学结果。[结果]所有患者均顺利完成手术,术中未出现血管、神经损伤等并发症。缝合钩组手术时间[(91.2±10.6) min vs (62.5±8.4) min, P<0.001]、切口总长度[(5.9±0.5) cm vs (5.1±0.6) cm, P<0.001]均显著长于Fast-fix组,但前者住院费用显著少于后者[(3.4±0.3)万元vs (4.3±0.7)万元, P<0.001]。两组Ramp撕裂长度、缝合针数、下地行走时间、切口愈合、住院时间比较差异均无统计学意义(P>0.05)。所有患者均获36~72个月随访。两组完全负重活动时间的差异无统计学意义(P>0.05)。术后1年及末次随访时,两组膝间隙压痛、麦氏征,轴移征、膝关节屈伸ROM、IKDC评分及Lysholm评分较术前均显著改善(P<0.05)。同一时间点,两组上述指标的差异均无统计学意义(P>0.05)。影像方面,与术前相比,术后1年,两组半月板损伤分级及胫骨平台后侧骨髓水肿均显著改善(P<0.05),相应时间点,两组上述指标的差异均无统计学意义(P>0.05)。术后1年MRI显示缝合钩组愈合率为90.5%、Fast-fix组为87.5%,差异无统计学意义(P>0.05)。[结论]关节镜下缝合钩和Fast-fix缝合半月板Ramp区Ⅳ型损伤均可获得满意疗效。展开更多
The influence of ramps on the transient rolling contact characteristics and damage mechanisms of switch rails remains unclear,presenting substantial challenges to the safety of railway operations.To this end,this pape...The influence of ramps on the transient rolling contact characteristics and damage mechanisms of switch rails remains unclear,presenting substantial challenges to the safety of railway operations.To this end,this paper constructs a transient rolling contact finite element model of the wheel-rail in switch under different ramps using ANSYS/LSDYNA method,and analyzes the tribology and damage characteristics when the wheel passes through the switch at a uniform speed.Our research findings reveal that the vibration induced in the switch rail during the wheel load transfer process leads to a step-like increase in the contact force.Moreover,the interaction between the wheel and the rail primarily involves slip contact,which may significantly contribute to the formation of corrugations on the switch rail.Additionally,the presence of large ramps exacerbates switch rail wear and rolling contact fatigue,resulting in a notable 13.2%increase in switch rail damage under 40‰ramp conditions compared to flat(0‰ramp)conditions.Furthermore,the large ramps can alter the direction of crack propagation,ultimately causing surface spalling of the rail.Therefore,large ramps intensify the dynamic interactions during the wheel load transfer process,further aggravating the crack and spalling damage to the switch rails.展开更多
胰腺癌是公认的最具侵袭性和致命性的恶性肿瘤之一,其中约20%的病例为胰体尾部癌症。由于该类型癌症生长迅速且早期缺乏明显症状,许多患者在诊断时已经错过了最佳治疗时机。手术是唯一可能治愈的手段,但传统的远端胰腺切除术和脾切除术...胰腺癌是公认的最具侵袭性和致命性的恶性肿瘤之一,其中约20%的病例为胰体尾部癌症。由于该类型癌症生长迅速且早期缺乏明显症状,许多患者在诊断时已经错过了最佳治疗时机。手术是唯一可能治愈的手段,但传统的远端胰腺切除术和脾切除术存在较高的阳性切缘率、较低的淋巴结清扫率和较差的总体生存率,已发表的证据表明经过传统手术治疗的病人,其五年生存率介于8%至22%之间。2003年,Strasberg等人提出了一种新的手术方法——根治性顺行模块化胰脾切除术(Radical Antegrade Modular Pancreatosplenectomy, RAMPS),旨在提供更好的肿瘤切除效果、提高R0切除率并改善患者的长期预后。RAMPS的五年总体生存率可高达30%~40%。随着腹腔镜技术的不断进步,腹腔镜下根治性顺行模块化胰脾切除术(Laparoscopic Radical Antegrade Modular Pancreatosplenectomy, L-RAMPS)作为一种微创手术,具有术后恢复快等优势,逐渐获得越来越多外科医师的关注。文章总结了这种手术的现状,并展望其未来发展。Pancreatic cancer is widely recognized as one of the most aggressive and lethal malignant tumors, with approximately 20% of cases occurring in the body and tail of the pancreas. Due to the rapid growth of this cancer and the lack of obvious symptoms in its early stages, many patients miss the opportunity for optimal treatment by the time of diagnosis. Surgery remains the only potentially curative option;however, traditional distal pancreatectomy and splenectomy are associated with high positive margin rates, low lymph node dissection rates, and poor overall survival. Published evidence shows that the five-year survival rate for patients treated with traditional surgery ranges from 8% to 22%. In 2003, Strasberg et al. proposed a new surgical technique—Radical Antegrade Modular Pancreatosplenectomy (RAMPS)—designed to improve tumor resection, increase the R0 resection rate, and enhance long-term prognosis. The five-year overall survival rate for RAMPS can reach 30%~40%. With the continuous advancement of laparoscopic technology, Laparoscopic Radical Antegrade Modular Pancreatosplenectomy (L-RAMPS), as a minimally invasive procedure, offers advantages such as faster postoperative recovery and is gradually gaining more attention from surgeons. This article provides an overview of the current status of this surgery and discusses its potential future development.展开更多
Photovoltaic(PV)systems are being increasingly implemented in the grid,and their intermittent output fluctuations threaten the stability of the grid,thereby requiring effective power ramp control(PRRC)strategies.In th...Photovoltaic(PV)systems are being increasingly implemented in the grid,and their intermittent output fluctuations threaten the stability of the grid,thereby requiring effective power ramp control(PRRC)strategies.In this study,we proposed a power fluctuation identification method to optimize the PRRC strategy.The K-means++cluster based on DTW used in this method,which clusters the historical PV power generation data into power curves corresponding to a specific weather type(sunny,cloudy,and rainy)in a time zone.Subsequently,wavelet decomposition is applied to discretize the power curves with extreme RR overrun to accurately identify the extreme fluctuation time zones.We conducted an analysis using minute-level data from a 100 kW PV plant in Arizona,which demonstrates that the proposed method can effectively identify high-risk periods.Weather patterns within the time zones were quantitatively identified using a weather probability model.A hardware-in-the-loop experimental platform was employed to validate two days of actual power data in Arizona,demonstrating the weather zoning accuracy of the method and the reasonableness of the control.The proposed methodology contributes significantly to PRRC strategy selection and parameter optimization(e.g.,ESS capacity storage allocation and APC power reserveΔP)in different time zones and weather conditions.展开更多
Traditional in situ biogeochemical transformation suffers from competition among crucial microorganisms and inadequate formation of reactive minerals,thus leading to the accumulation of toxic intermediates.In this stu...Traditional in situ biogeochemical transformation suffers from competition among crucial microorganisms and inadequate formation of reactive minerals,thus leading to the accumulation of toxic intermediates.In this study,three regulation schemes were proposed to solve these problems from the perspective of engineering mode.Results showed intermittent injection mode effectively reduced the accumulation of toxic intermediates but the reduction rate of tetrachloroethylene was decreased.And periodical supplementation of carbon and sulfur sources accelerated the removal of tetrachloroethylene but failed to reduce the accumulation of toxic products.While,regular supplementation of sulfate effectively weakened the competition of methanogens and increased the iron sulfide proportion on the surface of the minerals,thus reducing the accumulation of toxicity.Based on the results,this study obtained an effective engineering approach for practical site application.In addition,the main forms of active minerals capable ofβ-eliminating contaminants during biogeochemical transformation were identified in this study,including FeS,FeS_(2),and Fe_(3)S_(4).Furthermore,the engineered regulatory mechanism of this study was summarized through the analysis of microbial community structure and mineral morphology.The amendment promotes the production of minerals and thus controls the transformation pathway of contaminants by altering the abundance of sulfate-reducing bacteria and dissimilatory iron reducing bacteria.This mechanism can provide a basis for subsequent theoretical studies.展开更多
The purpose of this work relates to study on the characteristics of ultra thin gate oxide (2 5nm thickness) and the effect of metal Al,Zr,and Ta contamination on GOI.The controlled metallic contamination experiments...The purpose of this work relates to study on the characteristics of ultra thin gate oxide (2 5nm thickness) and the effect of metal Al,Zr,and Ta contamination on GOI.The controlled metallic contamination experiments are carried out by depositing a few ppm contaminated metal and low pH solutions on the wafers.The maximum metal surface concentration is controlled at about 10 12 cm -2 level in order to simulate metal contamination during ultra clean processing.A ramped current stress for intrinsic charge to breakdown measurements with gate injection mode is used to examine the characteristics of these ultra thin gate oxides and the effect of metal contamination on GOI.It is the first time to investigate the influence of metal Zr and Ta contamination on 2 5nm ultra thin gate oxide.It is demonstrated that there is little effect of Al contamination on GOI,while Zr contamination is the most detrimental to GOI,and early breakdown has happened to wafers contaminated by Ta.展开更多
文摘Hybrid nanofluids have gained significant attention for their superior thermal and rheological characteristics,offering immense potential in energy conversion,biomedical transport,and electromagnetic flow control systems.Understanding their dynamic behavior under coupled magnetic,rotational,and reactive effects is crucial for the development of efficient thermal management technologies.This study develops a neuro-fuzzy computational framework to examine the dynamics of a reactive Cu–TiO_(2)–H_(2)Ohybrid nanofluid flowing through a squarely elevated Riga tunnel.The governing model incorporates Hall and ion-slip effects,thermal radiation,and first-order chemical reactions under ramped thermo-solutal boundary conditions and rotational electromagnetic forces.Closed-form analytical solutions are derived via the Laplace transform method to describe the transient velocity,temperature,and concentration fields.To complement and validate the analytical model,an artificial neural network(ANN)optimized using the Levenberg–Marquardt backpropagation algorithm(ANN-LMBPA)is trained on datasets generated in Mathematica.Regression and error analyses confirm the model’s predictive robustness,with mean squared errors ranging between 10^(-4) and 10^(-9).In addition,an Adaptive Neuro-Fuzzy Inference System(ANFIS)is developed to estimate the heat transfer rate(HTR),achieving aminimal RMSE of 0.011012 for the heat transfer coefficient(HTC).The findings reveal that rotational motion and Hall–ion slip effects suppress primary velocity but enhance secondary flow,while the modified Hartmann number(Lorentz force)accelerates both components.Thermal radiation increases fluid temperature,whereas higher Schmidt numbers and reaction rates diminish solute concentration.The HTR decreases with increasing radiation and nanoparticle volume fraction,while the mass transfer rate(MTR)improves under stronger chemical reactivity.Overall,the proposed hybrid analytical–AI framework demonstrates high accuracy and efficiency,offering valuable insights for the design and optimization of electromagnetic nanofluid systems in advanced thermal and process engineering applications.
文摘Radiation effect on the natural convection flow of an optically thin viscous incompressible fluid near a vertical plate with ramped wall temperature in a porous medium has been studied. The exact solution of momentum and energy equations is obtained by the use of Laplace transform technique. The variations in fluid velocity and temperature are shown graphically whereas the numerical values of shear stress and the rate of heat transfer at the wall are presented in tabular form for various values of flow parameters. The results show that the fluid velocity increases with increase in Grashof number, Darcy number and time parameters whereas the fluid velocity decreases with increase in the radiation parameter and Prandtl number for ramped temperature as well as isothermal wall temperature. It is found that an increase in radiation parameter leads to rise the temperature for both ramped wall temperature as well as isothermal wall temperature. Further, it is found that an increase in Prandtl number leads to fall the temperature for both ramped wall temperature as well as isothermal wall temperature. The shear stress at the wall decreases with increases in either Prandtl number or porosity parameter while the result shows reverse in the case of radiation parameter. Finally, the rate of heat transfer is increased with increases in the radiation parameter for both ramped wall temperature as well as isothermal wall temperature.
文摘An exact analysis of the flow of an incompressible viscous fluid past an infinite vertical plate is conducted taking into account the presence of foreign mass or constant mass flux and ramped wall temperature. The dimensionless governing coupled linear partial differential equations are solved using the Laplace transform technique. Two different solutions for the fluid velocity are obtained–one valid for the fluids of Schmidt numbers different from unity, and the other for which the Schmidt number is unity. The effects of Prandtl number (Pr), Schmidt number (Sc), time (t) and mass to thermal buoyancy ratio parameter (N) for both aiding and opposing buoyancy effects on the velocity and skin-friction are studied. Also, the heat and mass transfer effects on the flow near a ramped temperature plate have been compared with the flow near a plate with constant temperature.
文摘The effect of radiation on the unsteady natural convection flow past an infinite vertical plate is presented, wherein the plate temperature is a ramped one. The fluid considered here is a gray, absorbing/emitting but a non-scattering medium. The influence of the various parameters entering into the problem on the velocity field, temperature field, skin friction and Nusselt number is studied.
文摘This study considers a theoretical analysis of natural convection flow of heat generating/absorbing fluid near an infinite vertical plate with ramped temperature. It is assumed that the bounding plate has a ramped temperature profile. Exact solutions of energy and momentum equations are obtained using the Laplacetransform techniques. Solutions are obtained for different values of the Prandtl number (Pr) and the heat sink parameter (S). Results of the ramped and isothermal temperature and velocity as well as Nusselt number and skin friction have been compared and presented with the help of graphs.
文摘The present paper is concerned with the study of flow,heat and mass transfer characteristics in the unsteady natural convective magneto hydrodynamics Casson fluid flow past over an oscillating vertical plate.The governing partial differential equations are solved analytically using Laplace transform technique and numerically using Matlab software.Expressions of skin friction,Nusselt number and Sherwood number are obtained.The features of the fluid flow,heat and mass transfer characteristics are analyzed by plotting graphs and the physical aspects are discussed in detail.
文摘本研究旨在深入探索RAMP(Range of Motion,Activation,Mobility,Potentiation)热身系统在初中体育教学中的应用效果,通过一个学期的对比实验,评估其对初中生体能水平、运动技能掌握、运动损伤预防以及体育课堂参与度的综合影响。研究选取某初中二年级2个班级共80名学生作为研究对象,采用随机对照试验设计,实验组采用RAMP热身系统,对照组沿用传统热身方式。结果表明,RAMP热身系统在提升体能、促进技能掌握、降低运动损伤风险及提高课堂参与度方面均表现出显著优势。本研究为初中体育教学提供了科学依据,建议推广RAMP热身系统以优化体育课堂结构,促进学生全面发展。
文摘[目的]比较关节镜下缝合钩和Fast-fix缝合Ⅳ型半月板Ramp区损伤的临床疗效。[方法]回顾性分析2016年1月—2020年10月45例前交叉韧带(anterior cruciate ligament, ACL)损伤合并Ⅳ型半月板Ramp损伤患者的临床资料。所有患者均取自体腘绳肌腱行ACL重建,依据术前医患沟通结果,21例应用缝合钩缝合Ramp损伤,24例应用Fast-fix缝合。对比患者围手术期、随访及影像学结果。[结果]所有患者均顺利完成手术,术中未出现血管、神经损伤等并发症。缝合钩组手术时间[(91.2±10.6) min vs (62.5±8.4) min, P<0.001]、切口总长度[(5.9±0.5) cm vs (5.1±0.6) cm, P<0.001]均显著长于Fast-fix组,但前者住院费用显著少于后者[(3.4±0.3)万元vs (4.3±0.7)万元, P<0.001]。两组Ramp撕裂长度、缝合针数、下地行走时间、切口愈合、住院时间比较差异均无统计学意义(P>0.05)。所有患者均获36~72个月随访。两组完全负重活动时间的差异无统计学意义(P>0.05)。术后1年及末次随访时,两组膝间隙压痛、麦氏征,轴移征、膝关节屈伸ROM、IKDC评分及Lysholm评分较术前均显著改善(P<0.05)。同一时间点,两组上述指标的差异均无统计学意义(P>0.05)。影像方面,与术前相比,术后1年,两组半月板损伤分级及胫骨平台后侧骨髓水肿均显著改善(P<0.05),相应时间点,两组上述指标的差异均无统计学意义(P>0.05)。术后1年MRI显示缝合钩组愈合率为90.5%、Fast-fix组为87.5%,差异无统计学意义(P>0.05)。[结论]关节镜下缝合钩和Fast-fix缝合半月板Ramp区Ⅳ型损伤均可获得满意疗效。
基金Project(2023YFB2604304)supported by the National Key R&D Program of ChinaProjects(52122810,51978586,51778542,U23A20666,52472458)supported by the National Natural Science Foundation of China+1 种基金Project(K2022G034)supported by the Technology Research and Development Program of China National Railway Group Co.Ltd.Projects(2020JDJQ0033,2023NSFSC0884)supported by Sichuan Province Science and Technology Support Program,China。
文摘The influence of ramps on the transient rolling contact characteristics and damage mechanisms of switch rails remains unclear,presenting substantial challenges to the safety of railway operations.To this end,this paper constructs a transient rolling contact finite element model of the wheel-rail in switch under different ramps using ANSYS/LSDYNA method,and analyzes the tribology and damage characteristics when the wheel passes through the switch at a uniform speed.Our research findings reveal that the vibration induced in the switch rail during the wheel load transfer process leads to a step-like increase in the contact force.Moreover,the interaction between the wheel and the rail primarily involves slip contact,which may significantly contribute to the formation of corrugations on the switch rail.Additionally,the presence of large ramps exacerbates switch rail wear and rolling contact fatigue,resulting in a notable 13.2%increase in switch rail damage under 40‰ramp conditions compared to flat(0‰ramp)conditions.Furthermore,the large ramps can alter the direction of crack propagation,ultimately causing surface spalling of the rail.Therefore,large ramps intensify the dynamic interactions during the wheel load transfer process,further aggravating the crack and spalling damage to the switch rails.
文摘胰腺癌是公认的最具侵袭性和致命性的恶性肿瘤之一,其中约20%的病例为胰体尾部癌症。由于该类型癌症生长迅速且早期缺乏明显症状,许多患者在诊断时已经错过了最佳治疗时机。手术是唯一可能治愈的手段,但传统的远端胰腺切除术和脾切除术存在较高的阳性切缘率、较低的淋巴结清扫率和较差的总体生存率,已发表的证据表明经过传统手术治疗的病人,其五年生存率介于8%至22%之间。2003年,Strasberg等人提出了一种新的手术方法——根治性顺行模块化胰脾切除术(Radical Antegrade Modular Pancreatosplenectomy, RAMPS),旨在提供更好的肿瘤切除效果、提高R0切除率并改善患者的长期预后。RAMPS的五年总体生存率可高达30%~40%。随着腹腔镜技术的不断进步,腹腔镜下根治性顺行模块化胰脾切除术(Laparoscopic Radical Antegrade Modular Pancreatosplenectomy, L-RAMPS)作为一种微创手术,具有术后恢复快等优势,逐渐获得越来越多外科医师的关注。文章总结了这种手术的现状,并展望其未来发展。Pancreatic cancer is widely recognized as one of the most aggressive and lethal malignant tumors, with approximately 20% of cases occurring in the body and tail of the pancreas. Due to the rapid growth of this cancer and the lack of obvious symptoms in its early stages, many patients miss the opportunity for optimal treatment by the time of diagnosis. Surgery remains the only potentially curative option;however, traditional distal pancreatectomy and splenectomy are associated with high positive margin rates, low lymph node dissection rates, and poor overall survival. Published evidence shows that the five-year survival rate for patients treated with traditional surgery ranges from 8% to 22%. In 2003, Strasberg et al. proposed a new surgical technique—Radical Antegrade Modular Pancreatosplenectomy (RAMPS)—designed to improve tumor resection, increase the R0 resection rate, and enhance long-term prognosis. The five-year overall survival rate for RAMPS can reach 30%~40%. With the continuous advancement of laparoscopic technology, Laparoscopic Radical Antegrade Modular Pancreatosplenectomy (L-RAMPS), as a minimally invasive procedure, offers advantages such as faster postoperative recovery and is gradually gaining more attention from surgeons. This article provides an overview of the current status of this surgery and discusses its potential future development.
基金supported by the Natural Science Research Project of Jiangsu Higher Education Institutions(23KJB470019)the Natural Science Foundation of Jiangsu Province under Grant BK20240594.
文摘Photovoltaic(PV)systems are being increasingly implemented in the grid,and their intermittent output fluctuations threaten the stability of the grid,thereby requiring effective power ramp control(PRRC)strategies.In this study,we proposed a power fluctuation identification method to optimize the PRRC strategy.The K-means++cluster based on DTW used in this method,which clusters the historical PV power generation data into power curves corresponding to a specific weather type(sunny,cloudy,and rainy)in a time zone.Subsequently,wavelet decomposition is applied to discretize the power curves with extreme RR overrun to accurately identify the extreme fluctuation time zones.We conducted an analysis using minute-level data from a 100 kW PV plant in Arizona,which demonstrates that the proposed method can effectively identify high-risk periods.Weather patterns within the time zones were quantitatively identified using a weather probability model.A hardware-in-the-loop experimental platform was employed to validate two days of actual power data in Arizona,demonstrating the weather zoning accuracy of the method and the reasonableness of the control.The proposed methodology contributes significantly to PRRC strategy selection and parameter optimization(e.g.,ESS capacity storage allocation and APC power reserveΔP)in different time zones and weather conditions.
基金supported by the National Natural Science Foundation of China(No.42277057).
文摘Traditional in situ biogeochemical transformation suffers from competition among crucial microorganisms and inadequate formation of reactive minerals,thus leading to the accumulation of toxic intermediates.In this study,three regulation schemes were proposed to solve these problems from the perspective of engineering mode.Results showed intermittent injection mode effectively reduced the accumulation of toxic intermediates but the reduction rate of tetrachloroethylene was decreased.And periodical supplementation of carbon and sulfur sources accelerated the removal of tetrachloroethylene but failed to reduce the accumulation of toxic products.While,regular supplementation of sulfate effectively weakened the competition of methanogens and increased the iron sulfide proportion on the surface of the minerals,thus reducing the accumulation of toxicity.Based on the results,this study obtained an effective engineering approach for practical site application.In addition,the main forms of active minerals capable ofβ-eliminating contaminants during biogeochemical transformation were identified in this study,including FeS,FeS_(2),and Fe_(3)S_(4).Furthermore,the engineered regulatory mechanism of this study was summarized through the analysis of microbial community structure and mineral morphology.The amendment promotes the production of minerals and thus controls the transformation pathway of contaminants by altering the abundance of sulfate-reducing bacteria and dissimilatory iron reducing bacteria.This mechanism can provide a basis for subsequent theoretical studies.
文摘The purpose of this work relates to study on the characteristics of ultra thin gate oxide (2 5nm thickness) and the effect of metal Al,Zr,and Ta contamination on GOI.The controlled metallic contamination experiments are carried out by depositing a few ppm contaminated metal and low pH solutions on the wafers.The maximum metal surface concentration is controlled at about 10 12 cm -2 level in order to simulate metal contamination during ultra clean processing.A ramped current stress for intrinsic charge to breakdown measurements with gate injection mode is used to examine the characteristics of these ultra thin gate oxides and the effect of metal contamination on GOI.It is the first time to investigate the influence of metal Zr and Ta contamination on 2 5nm ultra thin gate oxide.It is demonstrated that there is little effect of Al contamination on GOI,while Zr contamination is the most detrimental to GOI,and early breakdown has happened to wafers contaminated by Ta.
