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Research on the Influence of Cutting Condition on the Surface Microstruct ure of Ultra-thin Wall Parts in Ultrasonic Vibration Cutting 被引量:9
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作者 GAO Guo-fu, ZHAO Bo, JIAO Feng, LIU Chuan-shao (Department of Mechanical Engineering, Jiaozuo Institute of Technolog y, Henan 454000, China) 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期69-70,共2页
In many fields of high-tech industry the ultra-t hi n wall parts are employed. In this paper the experiments were carried out to dis cuss the surface microstructure of the camera’s guided drawtube by applying ult ras... In many fields of high-tech industry the ultra-t hi n wall parts are employed. In this paper the experiments were carried out to dis cuss the surface microstructure of the camera’s guided drawtube by applying ult rasonic vibration cutting device to the traditional lathe. The influence rule of the cutting condition on the surface roughness was put forward, which was drawn by comparing the ultrasonic cutting with the common cutting by use of the cemen ted carbide tool and the polycrystalline diamond (PCD) tool. The test results sh owed that the ultrasonic cutting performs better than the common cutting in the same condition. According to the test results analyzing, the surface characteriz ation is influenced clearly by the rigidity of the acoustic system and the machi ne tool, as well the setting height of the tool tip. Otherwise, the dense regula r low frequency vibration ripples will be scraped on the machined surface. When the tool tip is set higher than the rotating center of the work piece by three t imes of the amplitude of ultrasonic vibration, the vibration ripples behave alig ht; they turn light and shade alternatively when the tool tip is lower than the rotating center of the work piece by three times of the amplitude of ultrasonic vibration. According to the test result analyzing, the following conclusions are put forward: 1) The surface roughness in ultrasonic cutting is better than that in common cutting. Under a one third critical cutting velocity, the value of th e surface roughness in ultrasonic cutting rise slightly along with the cutting v elocity, while in common cutting it decreases contrast to the cutting velocity; the curves of the surface roughness in ultrasonic cutting and common cutting see m to be alike, both increase along with the feed rate and the cutting depth, but the value in ultrasonic cutting is smaller in the same condition.2) The influen ce of the coolant on the surface roughness cannot be ignored. The kerosene can b e employed to improve the surface roughness in ultrasonic machining.3) In ultras onic cutting process of aluminum alloy ultra-thin wall work piece, the PCD tool performs better than the cemented carbide tools.4) The vibration ripples result from the not enough rigidity of the acoustic system and the improper setting he ight of the tool tip. The departure of the tool tip from the rotating center of the work piece to some extent causes the vibration ripples on the machined surfa ce. 展开更多
关键词 ultra-thin wall parts ultrasonic cutting PCD t ool microstructure surface roughness
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Research on Influence of Cutting Conditions on Roundness of Ultra-thin Wall Parts in Ultrasonic Vibration Cutting 被引量:1
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作者 JIAO Feng 1, ZHAO Bo 1,2, LIU Chuan-shao 1, GAO Guo -fu 1 (1. Department of Mechanical Engineering, Jiaozuo Institute of Techno logy, Henan 454000, China 2. Institute of Mechanical Engineering, Shanghai Jiaotong University, Shanghai 200030, China) 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期75-76,共2页
In the paper, the experimental researches were carr ie d out to discuss the roundness forming rule and the influence of cutting paramet ers on roundness by ultrasonic vibration cutting of the camera’s guiding drawtu ... In the paper, the experimental researches were carr ie d out to discuss the roundness forming rule and the influence of cutting paramet ers on roundness by ultrasonic vibration cutting of the camera’s guiding drawtu be with 47.75 mm diameter and 0.6~1.5 mm wall thickness. The research results s h ow that the roundness error of ultra-thin wall parts in ultrasonic vibration cu tting is only one third of that in common cutting. The relations between the rou ndness error and the cutting parameters behave as: (1) The roundness error in co mmon cutting decreases gradually with the rise of cutting speed, while in ultras onic cutting, the roundness changes not obviously till the cutting speed is up t o a value, which is nearly equal to one third of the critical velocity. Then the roundness of workpiece will begin to increase slowly. (2) The roundness error i ncreases along with the feed rate both in common cutting and ultrasonic cutting. (3) Within the range of cutting depth in experiment, the influence of cutting d epth on the roundness error is more obvious in common cutting than that in ultra sonic vibration cutting. The conclusions are useful in machining such precise ul tra-thin wall parts. According to the tests, the following conclusions can be o btained: 1) Compared with common cutting, ultrasonic cutting can decrease effect ively roundness error of the workpiece. Under the same condition, the roundness error of the ultra-thin wall part in ultrasonic turning is about one third of t hat in common cutting. 2) In common cutting, cutting depth and feed rate have mu ch influence on the roundness and the influence of cutting velocity is little. W hile in ultrasonic cutting, the roundness was influenced heavily only when feed rate is more than 0.1 mm/r and cutting speed is more than 1/3 of the critical ro tation speed, cutting depth has little influence on the roundness in the experim ent. 3) Kerosene-oil is an optimum cutting fluid in machining ultra-thin wall workpiece. 4) To machine the ultra-thin wall precision part, ultrasonic cutting is the perfect method which can decrease the roundness error effectively an d ensure high quality of the surface. 展开更多
关键词 ultra-thin wall part ultrasonic vibration cutt ing ROUNDNESS guiding drawtube
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Strigolactones modulate cotton fiber elongation and secondary cell wall thickening 被引量:2
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作者 Yunze Wen Peng He +3 位作者 Xiaohan Bai Huizhi Zhang Yunfeng Zhang Jianing Yu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第6期1850-1863,共14页
Cotton is one of the most important economic crops in the world,and it is a major source of fiber in the textile industry.Strigolactones(SLs)are a class of carotenoid-derived plant hormones involved in many processes ... Cotton is one of the most important economic crops in the world,and it is a major source of fiber in the textile industry.Strigolactones(SLs)are a class of carotenoid-derived plant hormones involved in many processes of plant growth and development,although the functions of SL in fiber development remain largely unknown.Here,we found that the endogenous SLs were significantly higher in fibers at 20 days post-anthesis(DPA).Exogenous SLs significantly increased fiber length and cell wall thickness.Furthermore,we cloned three key SL biosynthetic genes,namely GhD27,GhMAX3,and GhMAX4,which were highly expressed in fibers,and subcellular localization analyses revealed that GhD27,GhMAX3,and GhMAX4 were localized in the chloroplast.The exogenous expression of GhD27,GhMAX3,and GhMAX4 complemented the physiological phenotypes of d27,max3,and max4 mutations in Arabidopsis,respectively.Knockdown of GhD27,GhMAX3,and GhMAX4 in cotton resulted in increased numbers of axillary buds and leaves,reduced fiber length,and significantly reduced fiber thickness.These findings revealed that SLs participate in plant growth,fiber elongation,and secondary cell wall formation in cotton.These results provide new and effective genetic resources for improving cotton fiber yield and plant architecture. 展开更多
关键词 STRIGOLACTONES fiber elongation secondary cell wall thickening COTTON
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Pectin methylesterase inhibitors GhPMEI53 and AtPMEI19 improve seed germination by modulating cell wall plasticity in cotton and Arabidopsis 被引量:2
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作者 Yayue Pei Yakong Wang +7 位作者 Zhenzhen Wei Ji Liu Yonghui Li Shuya Ma Ye Wang Fuguang Li Jun Peng Zhi Wang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第10期3487-3505,共19页
The germination process of seeds is influenced by the interplay between two opposing factors,pectin methylesterase(PME)and pectin methylesterase inhibitor(PMEI),which collectively regulate patterns of pectin methylest... The germination process of seeds is influenced by the interplay between two opposing factors,pectin methylesterase(PME)and pectin methylesterase inhibitor(PMEI),which collectively regulate patterns of pectin methylesterification.Despite the recognized importance of pectin methylesterification in seed germination,the specific mechanisms that govern this process remain unclear.In this study,we demonstrated that the overexpression of GhPMEI53is associated with a decrease in PME activity and an increase in pectin methylesterification.This leads to seed cell wall softening,which positively regulates cotton seed germination.AtPMEI19,the homologue in Arabidopsis thaliana,plays a similar role in seed germination to GhPMEI53,indicating a conserved function and mechanism of PMEI in seed germination regulation.Further studies revealed that GhPMEI53 and AtPMEI19 directly contribute to promoting radicle protrusion and seed germination by inducing cell wall softening and reducing mechanical strength.Additionally,the pathways of abscicic acid(ABA)and gibberellin(GA)in the transgenic materials showed significant changes,suggesting that GhPMEI53/AtPMEI19-mediated pectin methylesterification serves as a regulatory signal for the related phytohormones involved in seed germination.In summary,GhPMEI53 and its homologs alter the mechanical properties of cell walls,which influence the mechanical resistance of the endosperm or testa.Moreover,they impact cellular phytohormone pathways(e.g.,ABA and GA)to regulate seed germination.These findings enhance our understanding of pectin methylesterification in cellular morphological dynamics and signaling transduction,and contribute to a more comprehensive understanding of the PME/PMEI gene superfamily in plants. 展开更多
关键词 COTTON seed germination cell wall pectin demethylesterification PMEI ABA
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Effect of wall-disruption on nutrient composition and in vitro digestion of camellia and lotus bee pollens 被引量:1
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作者 Yuan Yuan Shun Zhong +3 位作者 Zeyuan Deng Guangyan Li Jinwu Zhang Hongyan Li 《Food Science and Human Wellness》 SCIE CSCD 2024年第3期1567-1577,共11页
The nutrient digestion,absorption and biological activity of bee pollen may be limited due to the complex pollen wall.Here,the effect of superfine grinding technology on the release of nutrients from bee pollen were i... The nutrient digestion,absorption and biological activity of bee pollen may be limited due to the complex pollen wall.Here,the effect of superfine grinding technology on the release of nutrients from bee pollen were investigated,and their antioxidant activities and in vitro digestion were explored in this study.Results showed that the content of nutrients in bee pollen increased after wall disruption.Among them,fat content increased by 22.55%-8.31%,protein content increased by 0.54%-4.91%,starch content increased by 36.31%-48.64%,soluble sugar content increased by 20.57%-29.67%,total phenolic acid content increased by 11.73%-86.98%and total flavonoids content increased by 14.29%-24.79%.At the same time,the antioxidant activity increased by 14.84%-46.00%.Furthermore,the active components such as phenolic compounds in the wall-disruption bee pollen were more readily to be released during the in vitro digestion,and easier to be absorbed because of their higher bioaccessibility.Antioxidant activities during in vitro digestion were also improved in walldisruption bee pollen.These findings provide evidence that bee pollen wall disruption was suggested,thus,it is more conducive to exerting the value of bee pollen in functional foods. 展开更多
关键词 Bee pollen NUTRIENTS wall disruption Phenolic compounds In vitro digestion
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Lateral earth pressure of granular backfills on retaining walls with expanded polystyrene geofoam inclusions under limited surcharge loading 被引量:1
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作者 Kewei Fan Guangqing Yang +2 位作者 Weilie Zou Zhong Han Yang Shen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第4期1388-1397,共10页
Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,t... Existing studies have focused on the behavior of the retaining wall equipped with expanded polystyrene(EPS)geofoam inclusions under semi-infinite surcharge loading rather than limited surcharge loading.In this paper,the failure mode and the earth pressure acting on the rigid retaining wall with EPS geofoam inclusions and granular backfills(henceforth referred to as EPS-wall),under limited surcharge loading are investigated through two-and three-dimensional model tests.The testing results show that different from the sliding of almost all the backfill in the EPS-wall under semi-infinite surcharge loading,only an approximately triangular backfill slides in the wall under limited surcharge loading.The distribution of the lateral earth pressure on the EPS-wall under limited surcharge loading is non-linear,and the distribution changes from the increase of the wall depth to the decrease with the increase of the limited surcharge loading.An approach based on the force equilibrium of a differential element is developed to predict the lateral earth pressure behind the EPS-wall subjected to limited surcharge loading,and its performance was fully validated by the three-dimensional model tests. 展开更多
关键词 Retaining wall Expanded polystyrene(EPS)geofoam Limited surcharge loading Lateral earth pressure Model test Prediction
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A spatiotemporal deep learning method for excavation-induced wall deflections 被引量:1
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作者 Yuanqin Tao Shaoxiang Zeng +3 位作者 Honglei Sun Yuanqiang Cai Jinzhang Zhang Xiaodong Pan 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第8期3327-3338,共12页
Data-driven approaches such as neural networks are increasingly used for deep excavations due to the growing amount of available monitoring data in practical projects.However,most neural network models only use the da... Data-driven approaches such as neural networks are increasingly used for deep excavations due to the growing amount of available monitoring data in practical projects.However,most neural network models only use the data from a single monitoring point and neglect the spatial relationships between multiple monitoring points.Besides,most models lack flexibility in providing predictions for multiple days after monitoring activity.This study proposes a sequence-to-sequence(seq2seq)two-dimensional(2D)convolutional long short-term memory neural network(S2SCL2D)for predicting the spatiotemporal wall deflections induced by deep excavations.The model utilizes the data from all monitoring points on the entire wall and extracts spatiotemporal features from data by combining the 2D convolutional layers and long short-term memory(LSTM)layers.The S2SCL2D model achieves a long-term prediction of wall deflections through a recursive seq2seq structure.The excavation depth,which has a significant impact on wall deflections,is also considered using a feature fusion method.An excavation project in Hangzhou,China,is used to illustrate the proposed model.The results demonstrate that the S2SCL2D model has superior prediction accuracy and robustness than that of the LSTM and S2SCL1D(one-dimensional)models.The prediction model demonstrates a strong generalizability when applied to an adjacent excavation.Based on the long-term prediction results,practitioners can plan and allocate resources in advance to address the potential engineering issues. 展开更多
关键词 Braced excavation wall deflections Deep learning Convolutional layer Long short-term memory(LSTM) Sequence to sequence(seq2seq)
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Damage Mechanism of Ultra-thin Asphalt Overlay(UTAO) based on Discrete Element Method
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作者 杜晓博 GAO Liang +4 位作者 RAO Faqiang 林宏伟 ZHANG Hongchao SUN Mutian XU Xiuchen 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第2期473-486,共14页
Aiming to analyze the damage mechanism of UTAO from the perspective of meso-mechanical mechanism using discrete element method(DEM),we conducted study of diseases problems of UTAO in several provinces in China,and fou... Aiming to analyze the damage mechanism of UTAO from the perspective of meso-mechanical mechanism using discrete element method(DEM),we conducted study of diseases problems of UTAO in several provinces in China,and found that aggregate spalling was one of the main disease types of UTAO.A discrete element model of UTAO pavement structure was constructed to explore the meso-mechanical mechanism of UTAO damage under the influence of layer thickness,gradation,and bonding modulus.The experimental results show that,as the thickness of UTAO decreasing,the maximum value and the mean value of the contact force between all aggregate particles gradually increase,which leads to aggregates more prone to spalling.Compared with OGFC-5 UTAO,AC-5 UTAO presents smaller maximum and average values of all contact forces,and the loading pressure in AC-5 UTAO is fully diffused in the lateral direction.In addition,the increment of pavement modulus strengthens the overall force of aggregate particles inside UTAO,resulting in aggregate particles peeling off more easily.The increase of bonding modulus changes the position where the maximum value of the tangential force appears,whereas has no effect on the normal force. 展开更多
关键词 ultra-thin asphalt overlay pavement distress discrete element method meso-mechanics damage mechanism
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Regulation of interlayer channels of graphene oxide nanosheets in ultra-thin Pebax mixed-matrix membranes for CO_(2) capture
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作者 Feifan Yang Yuanhang Jin +5 位作者 Jiangying Liu Haipeng Zhu Rong Xu Fenjuan Xiangli Gongping Liu Wanqin Jin 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第3期257-267,共11页
For the application of carbon capture by membrane process,it is crucial to develop a highly permeable CO_(2)-selective membrane.In this work,we reported an ultra-thin polyether-block-amide(Pebax)mixedmatrix membranes(... For the application of carbon capture by membrane process,it is crucial to develop a highly permeable CO_(2)-selective membrane.In this work,we reported an ultra-thin polyether-block-amide(Pebax)mixedmatrix membranes(MMMs)incorporated by graphene oxide(GO),in which the interlayer channels were regulated to optimize the CO_(2)/N_(2) separation performance.Various membrane preparation conditions were systematically investigated on the influence of the membrane structure and separation performance,including the lateral size of GO nanosheets,GO loading,thermal reduction temperature,and time.The results demonstrated that the precisely regulated interlayer channel of GO nanosheets can rapidly provide CO_(2)-selective transport channels due to the synergetic effects of size sieving and preferential adsorption.The GO/Pebax ultra-thin MMMs exhibited CO_(2)/N_(2) selectivity of 72 and CO_(2) permeance of 400 GPU(1 GPU=106 cm^(3)(STP)·cm^(2)·s^(-1)·cmHg^(-1)),providing a promising candidate for CO_(2) capture. 展开更多
关键词 Mixed-matrix membrane ultra-thin membrane Pebax Graphene oxide CO_(2) capture
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Experimental and numerical study on protective effect of RC blast wall against air shock wave
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作者 Xin-zhe Nian Quan-min Xie +2 位作者 Xin-li Kong Ying-kang Yao Kui Huang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期567-579,共13页
Prototype experiments were carried out on the explosion-proof performance of the RC blast wall.The mass of TNT detonated in the experiments is 5 kg and 20 kg respectively.The shock wave overpressure was tested in diff... Prototype experiments were carried out on the explosion-proof performance of the RC blast wall.The mass of TNT detonated in the experiments is 5 kg and 20 kg respectively.The shock wave overpressure was tested in different regions.The above experiments were numerically simulated,and the simulated shock wave overpressure waveforms were compared with that tested and given by CONWEP program.The results show that the numerically simulated waveform is slightly different from the test waveform,but similar to CONWEP waveform.Through dimensional analysis and numerical simulation under different working conditions,the equation for the attenuation rate of the diffraction overpressure behind the blast wall was obtained.According to the corresponding standards,the degree of casualties and the damage degree of the brick concrete building at a certain distance behind the wall can be determined when parameters are set.The above results can provide a reference for the design and construction of the reinforced concrete blast wall. 展开更多
关键词 Blast wall Shock wave DIFFRACTION OVERPRESSURE Protection
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Consistency between domain wall oscillation modes and spin wave modes in nanostrips
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作者 董新伟 吴振江 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期511-516,共6页
Investigations on domain wall(DW) and spin wave(SW) modes in a series of nanostrips with different widths and thicknesses have been carried out using micromagnetic simulation. The simulation results show that the freq... Investigations on domain wall(DW) and spin wave(SW) modes in a series of nanostrips with different widths and thicknesses have been carried out using micromagnetic simulation. The simulation results show that the frequencies of SW modes and the corresponding DW modes are consistent with each other if they have the same node number along the width direction. This consistency is more pronounced in wide and thin nanostrips, favoring the DW motion driven by SWs.Further analysis of the moving behavior of a DW driven by SWs is also carried out. The average DW speed can reach a larger value of ~ 140 m/s under two different SW sources. We argue that this study is very meaningful for the potential application of DW motion driven by SWs. 展开更多
关键词 micromagnetic simulation domain wall spin wave
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Resilient performance of self-centering hybrid rocking walls with curved interface under pseudo-static loading
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作者 Su Xing Yan Shi +1 位作者 Sun Xianglei Wang Tao 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第1期65-85,共21页
Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during ... Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during the rocking process.An innovative RW with a curved interface is proposed to prevent interfacial corners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed tendons.Moreover,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral resistance.Two SCRW specimens and one monolithic reinforced concrete(RC)shear wall(SW)were tested under pseudo-static loading to compare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the SCRW.The key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were explored.The results show that nonlinear deformations of the SCRW are concentrated along the interface between the SCRW and the foundation,avoiding damage within the SCRW.The restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic SW.In addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress concentration and crush of concrete.The rocking range of the rocking center is about 41.4%of the width of the SCRW. 展开更多
关键词 self-centering hybrid rocking wall(SCRW) monolithic shear wall(SW) earthquake resilient performance(ERP) curved interface rocking center
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Effect of Bogie Cavity End Wall Inclination on Flow Field and Aerodynamic Noise in the Bogie Region of High-Speed Trains
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作者 Jiawei Shi Jiye Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第5期2175-2195,共21页
Combining the detached eddy simulation(DES)method and Ffowcs Williams-Hawkings(FW-H)equation,the effect of bogie cavity end wall inclination on the flow field and aerodynamic noise in the bogie region is numerically s... Combining the detached eddy simulation(DES)method and Ffowcs Williams-Hawkings(FW-H)equation,the effect of bogie cavity end wall inclination on the flow field and aerodynamic noise in the bogie region is numerically studied.First,the simulation is conducted based on a simplified cavity-bogie model,including five cases with different inclination angles of the front and rear walls of the cavity.By comparing and analyzing the flow field and acoustic results of the five cases,the influence of the regularity and mechanism of the bogie cavity end wall inclination on the flow field and the aerodynamic noise of the bogie region are revealed.Then,the noise reduction strategy determined by the results of the simplified cavity-bogie model is applied to a three-car marshaling train model to verify its effectiveness when applied to the real train.The results reveal that the forward inclination of the cavity front wall enlarges the influence area of shear vortex structures formed at the leading edge of the cavity and intensifies the interaction between the vortex structures and the front wheelset,frontmotor,and front gearbox,resulting in the increase of the aerodynamic noise generated by the bogie itself.The backward inclination of the cavity rear wall is conducive to guiding the vortex structures flow out of the cavity and weakening the interaction between the shear vortex structures and the cavity rear wall,leading to the reduction of the aerodynamic noise generated by the bogie cavity.Inclining the rear end wall of the foremost bogie cavity of the head car is a feasible aerodynamic noise reduction measure for high-speed trains. 展开更多
关键词 BOGIE cavity flow aerodynamic noise end wall inclination
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Loss of energetic particles due to feedback control of resistive wall mode in HL-3
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作者 Yifei ZHAO Yueqiang LIU +7 位作者 Guangzhou HAO Zhengxiong WANG Guanqi DONG Shuo WANG Chunyu LI Guanming YANG Yutian MIAO Yongqin WANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第10期17-28,共12页
Effects of three-dimensional(3D)magnetic field perturbations due to feedback control of an unstable n=1(n is toroidal mode number)resistive wall mode(RWM)on the energetic particle(EP)losses are systematically investig... Effects of three-dimensional(3D)magnetic field perturbations due to feedback control of an unstable n=1(n is toroidal mode number)resistive wall mode(RWM)on the energetic particle(EP)losses are systematically investigated for the HL-3 tokamak.The MARS-F(Liu et al 2000 Phys.Plasmas 73681)code,facilitated by the test particle guiding center tracing module REORBIT,is utilized for the study.The RWM is found to generally produce no EP loss for cocurrent particles in HL-3.Assuming the same perturbation level at the sensor location for the close-loop system,feedback produces nearly the same loss of counter-current EPs compared to the open-loop case.Assuming however that the sensor signal is ten times smaller in the close-loop system than the open-loop counter part(reflecting the fact that the RWM is more stable with feedback),the counter-current EP loss is found significantly reduced in the former.Most of EP losses occur only for particles launched close to the plasma edge,while particles launched further away from the plasma boundary experience much less loss.The strike points of lost EPs on the HL-3 limiting surface become more scattered for particles launched closer to the plasma boundary.Taking into account the full gyro-orbit of particles while approaching the limiting surface,REORBIT finds slightly enhanced loss fraction. 展开更多
关键词 energetic particles resistive wall mode HL-3
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Thin-walled and large-sized magnesium alloy die castings for passenger car cockpit:Application,materials,and manufacture
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作者 Lei Zhan Yu-meng Sun +6 位作者 Yang Song Chun-hua Kong Kai Ma Bai-xin Dong Hong-yu Yang Shi-li Shu Feng Qiu 《China Foundry》 SCIE EI CAS CSCD 2024年第5期525-545,共21页
In order to effectively reduce energy consumption and increase range mile,new energy vehicles represented by Tesla have greatly aroused the application of integrated magnesium(Mg)alloy die casting technology in automo... In order to effectively reduce energy consumption and increase range mile,new energy vehicles represented by Tesla have greatly aroused the application of integrated magnesium(Mg)alloy die casting technology in automobiles.Previously,the application of Mg alloys in automobiles,especially in automotive cockpit components,is quite extensive,while it has almost disappeared for a period of time due to its relatively high cost,causing a certain degree of information loss in the application technology of Mg alloy parts in automobiles.The rapid development of automotive technology has led to a higher requirement for the automotive components compared with those traditional one.Therefore,whatever the components themselves,or the Mg alloy materials and die casting process have to face an increasing challenge,needing to be upgraded.In addition,owing to its high integration characteristics,the application of Mg alloy die casting technology in large-sized and thin-walled automotive parts has inherent advantages and needs to be expanded urgently.Indeed,it necessitates exploring advance Mg alloys and new product structures and optimizing die casting processes.This article summarizes and analyzes the development status of thin-walled and large-sized die casting Mg alloy parts in passenger car cockpit and corresponding material selection methods,die casting processes as well as mold design techniques.Furthermore,this work will aid researchers in establishing a comprehensive understanding of the manufacture of thin-walled and large-sized die casting Mg alloy parts in automobile cockpit.It will also assist them in developing new Mg alloys with improved comprehensive performance and new processes to meet the high requirements for die casting automotive components. 展开更多
关键词 Mg alloys thin wall large size automotive part die casting
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An impact sensitivity assessment method of spacecraft based on virtual exterior wall
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作者 Runqiang Chi Yuyan Liu +1 位作者 Diqi Hu Baojun Pang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期142-157,共16页
The impact sensitivity assessment of spacecraft is to obtain the probability of spacecraft encountering the OD/M(orbital debris or meteoroid),which is a prerequisite for survivability assessment of on-orbit spacecraft... The impact sensitivity assessment of spacecraft is to obtain the probability of spacecraft encountering the OD/M(orbital debris or meteoroid),which is a prerequisite for survivability assessment of on-orbit spacecraft.An impact sensitivity assessment method of spacecraft based on virtual exterior wall was proposed to improve the computational efficiency.This method eliminates determination of the outermost surface elements of the spacecraft before generating the debris rays,which are assumed to originate from a non-concave virtual wall that completely wraps the spacecraft.The Dist Mesh method was adopted for the generating of the virtual wall to ensure its mesh quality.The influences of the sizes,mesh densities,shapes of the virtual wall on the efficiency and accuracy were considered to obtain the best combination of the size and mesh density of the wall and spacecraft.The results of this method were compared with those of S3DE(Survivability of Spacecraft in Space Debris Environment),BUMPER,MDPANTO,ESABASE2/Debris to verify the feasibility of the method.The PCHIP(Piecewise Cubic Hermite Interpolating Polynomial)was used to fit the size vs.flux relationship of the space debris to acquire the impact probability of OD/M with arbitrary size on the spacecraft. 展开更多
关键词 Sensitivity OD/M SPACECRAFT Virtual exterior wall
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Upregulation of the glycine-rich protein-encoding gene GhGRPL enhances plant tolerance to abiotic and biotic stressors by promoting secondary cell wall development
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作者 Wanting Yu Yonglu Dai +17 位作者 Junmin Chen Aimin Liang Yiping Wu Qingwei Suo Zhong Chen Xingying Yan Chuannan Wang Hanyan Lai Fanlong Wang Jingyi Zhang Qinzhao Liu Yi Wang Yaohua Li Lingfang Ran Jie Xiang Zhiwu Pei Yuehua Xiao Jianyan Zeng 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第10期3311-3327,共17页
Abiotic and biotic stressors adversely affect plant survival,biomass generation,and crop yields.As the global availability of arable land declines and the impacts of global warming intensify,such stressors may have in... Abiotic and biotic stressors adversely affect plant survival,biomass generation,and crop yields.As the global availability of arable land declines and the impacts of global warming intensify,such stressors may have increasingly pronounced effects on agricultural productivity.Currently,researchers face the overarching challenge of comprehensively enhancing plant resilience to abiotic and biotic stressors.The secondary cell wall plays a crucial role in bolstering the stress resistance of plants.To increase plant resistance to stress through genetic manipulation of the secondary cell wall,we cloned a cell wall protein designated glycine-rich protein-like(GhGRPL)from cotton fibers,and found that it is specifically expressed during the period of secondary cell wall biosynthesis.Notably,this protein differs from its Arabidopsis homolog,AtGRP,since its glycine-rich domain is deficient in glycine residues.GhGRPL is involved in secondary cell wall deposition.Upregulation of GhGRPL enhances lignin accumulation and,consequently,the thickness of the secondary cell walls,thereby increasing the plant’s resistance to abiotic stressors,such as drought and salinity,and biotic threats,including Verticillium dahliae infection.Conversely,interference with GhGRPL expression in cotton reduces lignin accumulation and compromises that resistance.Taken together,our findings elucidate the role of GhGRPL in regulating secondary cell wall development through its influence on lignin deposition,which,in turn,reinforces cell wall robustness and impermeability.These findings highlight the promising near-future prospect of adopting GhGRPL as a viable,effective approach for enhancing plant resilience to abiotic and biotic stress factors. 展开更多
关键词 glycine-rich protein-like secondary cell wall abiotic stress biotic stress stress resistance
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Experimental and numerical study regarding H-steel all-bolted connection steel frame with composite wall boards
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作者 Fan Min Guo Hongchao +2 位作者 Li Shen Wang Zhenshan Wang Huaqiang 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第2期427-443,共17页
H-steel all-bolted connection steel frame structures with heat preservation and decoration composite wall boards were investigated and the seismic performances of three scaled specimens were studied.The failure modes,... H-steel all-bolted connection steel frame structures with heat preservation and decoration composite wall boards were investigated and the seismic performances of three scaled specimens were studied.The failure modes,hysteresis curves,bearing capacity,ductility,energy dissipation capacity,stiffness degradation and strain distribution were discussed.The calculation method of structural theoretical internal force was presented.The results showed that the overall structural seismic performance was better,and the structural ductility met the demands of elastic-plastic inter-story drift angle for seismic design.The H-steel weak-axis connection structure obtained better energy dissipation capacity,and its bearing capacity and stiffness were slightly different from the strong-axis connection.The heat preservation and decoration performance of composite wallboard and the all-bolted connection of the steel frame realized prefabrication during the whole construction period.The plastic hinge of the steel beam can be moved outwards because of the L-angles,which effectively avoids stress concentration in joint areas and expands the plastic hinge range.The errors between the theoretical structural capacity calculated by the plastic analysis method and the test results were within 2.44%.In addition,structural failure mechanisms and bearing capacities were verified by the finite element(FE)analysis,and the effects of the main parameters on the structures were investigated.The FE verification results were the same as in the test.The research results provide theoretical support and technical guidance for the application of thermal insulation and decorative composite wall panels in H-shaped steel all-bolted steel frames. 展开更多
关键词 composite wall boards all-bolted steel frame H-steel low-cyclic loading failure modes
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Restraint effect of partition wall on the tunnel floor heave in layered rock mass
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作者 YANG Yunyun HUANG Da +2 位作者 ZHONG Zhu LIU Yang PENG Jianbing 《Journal of Mountain Science》 SCIE CSCD 2024年第7期2462-2479,共18页
The presence of horizontal layered rocks in tunnel engineering significantly impacts the stability and strength of the surrounding rock mass,leading to floor heave in the tunnel.This study focused on preparing layered... The presence of horizontal layered rocks in tunnel engineering significantly impacts the stability and strength of the surrounding rock mass,leading to floor heave in the tunnel.This study focused on preparing layered specimens of rock-like material with varying thickness to investigate the failure behaviors of tunnel floors.The results indicate that thin-layered rock mass exhibits weak interlayer bonding,causing rock layers near the surface to buckle and break upwards when subjected to horizontal squeezing.With an increase in the layer thickness,a transition in failure mode occurs from upward buckling to shear failure along the plane,leading to a noticeable reduction in floor heave deformation.The primary cause of significant deformation in floor heave is upward buckling failure.To address this issue,the study proposes the installation of a partition wall in the middle of the floor to mitigate heave deformation of the rock layers.The results demonstrate that the partition wall has a considerable stabilizing effect on the floor,reducing the zone of buckling failure and minimizing floor heave deformation.It is crucial for the partition wall to be sufficiently high to prevent buckling failure and ensure stability.Through simulation calculations on an engineering example,it is confirmed that implementing a partition wall can effectively reduce floor heave and enhance the stability of tunnel floor. 展开更多
关键词 Layered rock Floor heave Horizontal compression test Failure behavior Partition wall
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Influence of Various Earth-Retaining Walls on the Dynamic Response Comparison Based on 3D Modeling
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作者 Muhammad Akbar Huali Pan +2 位作者 Jiangcheng Huang Bilal Ahmed Guoqiang Ou 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第6期2835-2863,共29页
The present work aims to assess earthquake-induced earth-retaining(ER)wall displacement.This study is on the dynamics analysis of various earth-retaining wall designs in hollow precast concrete panels,reinforcement co... The present work aims to assess earthquake-induced earth-retaining(ER)wall displacement.This study is on the dynamics analysis of various earth-retaining wall designs in hollow precast concrete panels,reinforcement concrete facing panels,and gravity-type earth-retaining walls.The finite element(FE)simulations utilized a 3D plane strain condition to model full-scale ER walls and numerous nonlinear dynamics analyses.The seismic performance of differentmodels,which includes reinforcement concrete panels and gravity-type and hollowprecast concrete ER walls,was simulated and examined using the FE approach.It also displays comparative studies such as stress distribution,deflection of the wall,acceleration across the wall height,lateral wall displacement,lateral wall pressure,and backfill plastic strain.Three components of the created ER walls were found throughout this research procedure.One is a granular reinforcement backfill,while the other is a wall-facing panel and base foundation.The dynamic response effects of varied earth-retaining walls have also been studied.It was discovered that the facing panel of the model significantly impacts the earthquake-induced displacement of ER walls.The proposed analytical model’s validity has been evaluated and compared with the reinforcement concrete facing panels,gravity-type ER wall,scientifically available data,and American Association of State Highway and Transportation Officials(AASHTO)guidelines results based on FE simulation.The results of the observations indicate that the hollow prefabricated concrete ER wall is the most feasible option due to its lower displacement and high-stress distribution compared to the two types.The methodology and results of this study establish standards for future analogous investigations and professionals,particularly in light of the increasing computational capabilities of desktop computers. 展开更多
关键词 Seismic analysis finite element modeling earth-retaining ER walls dynamic response structural resilience
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