The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficien...The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficiency and low-cost manufacturing of the component.Blank design is the key part of plastic forming process design.For spinning-rolling process,the shape and size of the blank play a crucial role in process stability,deformation behavior and dimensional accuracy.So this work proposes a blank design method to determine the geometry structure and sizes of the blank.The mathematical model for calculating the blank size has been deduced based on volume conservation and neutral layer length invariance principle.The FE simulation and corresponding trial production of an actual big-tapered profiled ring disk show that the proposed blank design method is applicative.In order to obtain a preferred blank,the influence rules of blank size determined by different deformation degrees(rolling ratio k)on the spinning-rolling process are revealed by comprehensive FE simulations.Overall considering the process stability,circularity of the deformed ring disk and forming forces,a reasonable range of deformation degree(rolling ratio k)is recommended for the blank design of the new spinning-rolling process.展开更多
Profiled monolayer cBN wheel was induction brazed for grinding of titanium dovetail slot in this study.Aimed at acquiring a uniform temperature distribution along the profiled surface and reducing the thermal deformat...Profiled monolayer cBN wheel was induction brazed for grinding of titanium dovetail slot in this study.Aimed at acquiring a uniform temperature distribution along the profiled surface and reducing the thermal deformation of the brazed wheel,a finite element model was established to investigate the temperature uniformity during induction brazing.A suitable induction coil and the related working parameters were designed and chosen based on the simulation results.Ag-Cu-Ti alloy and cBN grains were applied in the induction brazing experiment.The results showed geometric deformation of the brazed wheel was no more than 0.01 mm and chemical reaction layer were found on the brazed joint interface.Further validation tests were carried out by grinding of Ti-6 Al-4 V alloy.Compared to the electroplated wheel,the brazed wheel showed better performance such as low specific grinding energy and good ground quality in grinding of Ti-6 Al-4 V alloy.Abrasion wear was found to be the main failure mode for the induction brazed wheel,while adhesion and grains pull-out were the main failure mode for the electroplated wheel.展开更多
The most common and abundant DNA modification is 5-methylcytosine（5mC）,which has been well-established as an epigenetic mark regulating gene expression in eukaryotes（Jones,2012）.Another DNA modification N^6-methyl...The most common and abundant DNA modification is 5-methylcytosine（5mC）,which has been well-established as an epigenetic mark regulating gene expression in eukaryotes（Jones,2012）.Another DNA modification N^6-methyldeoxyadenosine（6mA）,previously reported as a widespread DNA methylation in prokaryotes.展开更多
The final quality of complex conical-section rings depends on co-design of multiple processes in forming process chain.In this study,for a complex aeroengine casing ring with a large slope and a flange on its end,a co...The final quality of complex conical-section rings depends on co-design of multiple processes in forming process chain.In this study,for a complex aeroengine casing ring with a large slope and a flange on its end,a co-design method of the forming process chain is put forward towards the objective of precision forming,which not only proposes a standard process route composed of multiple processes of upsetting,punching,rectangular ring rolling,loose tooling forging and profiled ring rolling,but also presents co-design methods of dies and blanks for all the processes.For profiled ring rolling,a design method of preformed blank that makes the blank and the target conical-section ring have the same axial volume distribution is proposed.By the method,the axial metal redistribution during the process can be alleviated greatly thus improving the forming stability and precision of the ring.Based on the geometric features of designed preformed blank,design methods of blanks and dies for loose tolling forging,rectangular ring rolling,punching and upsetting are proposed sequentially.In view of the key roles of loose tooling forging(manufacturing the preformed blank)and profiled ring rolling on the final quality of the conical ring parts,inherited FE simulations for these two processes are performed to verify the proposed design methods and determine appropriate design parameter.It is demonstrated that the proposed design method has significant advantages in improving forming precision.Besides,a suggestive value 1.5 of the rolling ratio for profiled ring rolling(a key design parameter)is given based on comprehensive consideration of multiple indicators such as ring roundness,deformation uniformity and forming load.The corresponding industrial experiments performed illustrate that a high forming precision of the conical-section aeroengine casing ring is achieved.展开更多
An an alytical model based on linear decreasi ng leveli ng scheme was proposed to inv estigate the longitu din ally profiled plate leveling process.Considering the variable cross-sectional thickness of longitudinally ...An an alytical model based on linear decreasi ng leveli ng scheme was proposed to inv estigate the longitu din ally profiled plate leveling process.Considering the variable cross-sectional thickness of longitudinally profiled plate and the dynamic reductions in leveling rolls,the reduction models of upper and lower rolls,the leveling force model and the leveling moment model were established,respectively,based on linear decreasing leveling scheme.Moreover,the finite element model of longitudinally profiled plate leveling process was established based on ABAQUS.Then,the total displacements of upper and lower rolls,the leveling force and the stress distribution of longifudinally profiled plate in the leveling process were calculated.To verify the validity of the proposed models,calculated leveling forces were compared with the measured values,and very good agreements are found.Calculated results show that linear decreasing leveling scheme is suitable for leveling longitudinally profiled plate.展开更多
How to utilize existing flow control mechanisms to make profiled end wall design more flexible,efficient,and physical is a meaningful challenge.This study presents a three-dimensional inverse method for profiled end w...How to utilize existing flow control mechanisms to make profiled end wall design more flexible,efficient,and physical is a meaningful challenge.This study presents a three-dimensional inverse method for profiled end wall design to achieve the application of flow control mechanisms.The predetermined pressure distribution on the end wall is reached by modifying the end wall geometry during flow field calculation.A motion velocity model is derived from the normal momentum equation of the moving no-slip boundary to modify the end wall geometry.A Reynolds-Averaged Navier-Stokes(RANS)solver based on the Semi-Implicit Method for Pressure Linked Equations(SIMPLE)algorithm is adopted to simulate the flow field.Based on the mechanism understanding obtained through numerical optimization results,this study adopts the inverse method to redesign an optimized end wall in a compressor cascade.The results indicate that the redesigned end wall exhibits better loss reduction,reducing the overall total pressure loss by 5.5%,whereas the optimized end wall reduces it by 3%.The inverse method allows the imposition of desired influences on the end wall flow without constructing a database,making it highly flexible,efficient,and physical.展开更多
Considering the variable cross section thickness of longitudinal profiled plate and the dynamic reductions of straightening rolls,an analytical model combining curvature integral method with linear decreasing straight...Considering the variable cross section thickness of longitudinal profiled plate and the dynamic reductions of straightening rolls,an analytical model combining curvature integral method with linear decreasing straightening scheme was proposed to investigate the longitudinal profiled plate straightening process.Moreover,the calculation flow and solution algorithm of longitudinal profiled plate straightening process were presented.To verify the proposed model,calculated straightening forces were compared with the measured values,and very good agreements were achieved.Then,the reduction,contact angle,reverse bending curvature,residual curvature,straightening force and straightening moment of longitudinal profiled plate in the straightening process were calculated and analyzed,and the calculated results show that the curvature integral method can be used to reveal the mechanism of longitudinal profiled plate straightening.展开更多
A multi-shape representation approach for measuring geometrical properties of profiled fibers was presented.From closed edge chains of a fiber cross section,three evenly spaced vertices were selected to form a triangl...A multi-shape representation approach for measuring geometrical properties of profiled fibers was presented.From closed edge chains of a fiber cross section,three evenly spaced vertices were selected to form a triangle by changing the vertices' spacing,or the step length,the Triangle Area Representation(TAR)was calculated with a special determinant.The bend direction of the two consecutive lines drawn by three vertices determined the sign of the TAR.TARN and TARP were negative and positive extensions of TAR,and used to analyze concave and convex segments on the boundary.The length of TARN measured the size of concaveness.Multi-scale TARPs together with TARN can help to detect fiber conglutinations.展开更多
The key technique of a kinetic energy rod(KER) warhead is to control the flight attitude of rods. The rods are usually designed to different shapes. A new conceptual KER named profiled rod which has large L/D ratio is...The key technique of a kinetic energy rod(KER) warhead is to control the flight attitude of rods. The rods are usually designed to different shapes. A new conceptual KER named profiled rod which has large L/D ratio is described in this paper. The elastic dynamic equations of this profiled rod flying at high velocity after detonation are set up on the basis of Euler-Bernoulli beam, and the aeroelastic deformation of profiled rod is calculated by semi-analytical method for calculating the vibration characteristics of variable cross-section beam. In addition, the aeroelastic deformation of the undeformed profiled rod and the aeroelastic deformation of deformed profiled rod which is caused by the detonation of explosive are simulated by computational fluid dynamic and finite element method(CFD/FEM), respectively. A satisfactory agreement of these two methods is obtained by the comparison of two methods. The results show that the semi-analytical method for calculating the vibration characteristics of variable cross-section beam is applied to analyze the aeroelastic deformation of profiled rod flying at high velocity.展开更多
Longitude profiled cladded sheet is obtained by rolling bimetal cladded sheet with variable gauge rolling technology.The longitude profiled rolling process of Cu/Al cladded sheets was studied by finite element method ...Longitude profiled cladded sheet is obtained by rolling bimetal cladded sheet with variable gauge rolling technology.The longitude profiled rolling process of Cu/Al cladded sheets was studied by finite element method and experiments.The rolling force rises with the increase in reduction,and a sudden change appears at the end of the thickness variation zone.The thickness ratio of copper layer is enlarged after rolling owing to its relatively large deformation resistance and continues to rise with the increase in reduction rate.Lower elongation of copper side leads to the warpage of exit metal to copper side,which further hinders the deformation of copper.The influence of asymmetric rolling parameters indicates that increasing the work roll diameter ratio,speed radio,and friction coefficient on Al side can reduce the warpage when the reduction rate is below a certain value depending on the thickness ratio and other rolling parameters.Comparison of experiments and simulation results showed good agreement and verified the finite element model.展开更多
A new Kinetic Energy Rod( KER) warhead named profiled rod warhead is proposed in this paper.Based on the design of profiled rod warhead,a model of profiled rod driven by detonation is established. The detonation proce...A new Kinetic Energy Rod( KER) warhead named profiled rod warhead is proposed in this paper.Based on the design of profiled rod warhead,a model of profiled rod driven by detonation is established. The detonation process is simulated by ANSYS / LS-DYNA,and the deployment velocity and initial flight attitude of rod are achieved. In addition,static rod deployment testing are performed to investigate the damage effect,the spatial flight attitude and deployment velocity. A satisfactory agreement is obtained by the comparison between numerical results and testing results. Meanwhile,the profiled rod studies are conducted to determine a higher penetrability compared with traditional cylindrical rods. Rigid body dynamics equations of profiled rod,which accounts for the influence of air resistance,are set up to predict the flight trajectory of long-distance. The results show that the profiled rod may provide a better penetration angle which still maintains a significant penetrability against projectiles when the rods move off long-distance range.展开更多
In order to achieve a lower consumed energy, the performance of a new type of rotating volumetric pump with two profiled rotors (variant I) which is compared with a centrifugal pump (variant II) is presented. The...In order to achieve a lower consumed energy, the performance of a new type of rotating volumetric pump with two profiled rotors (variant I) which is compared with a centrifugal pump (variant II) is presented. The analysis regarding the same flow rate of transported liquid and the same pressure increases points out the conduct of the system at the variation of the key operating parameters. The actual driving power of the rotating volumetric pump is higher stating that is more advantageous in operation. The effective efficiency of the system is improved due to the original constructive solution.展开更多
Composite slabs with profiled steel sheet are widely applied in practical structures now. Plenty of literatures can be available about simply supported composite slabs with single span. However, continuous slabs alway...Composite slabs with profiled steel sheet are widely applied in practical structures now. Plenty of literatures can be available about simply supported composite slabs with single span. However, continuous slabs always exist in high-rise building structures. In order to obtain the ultimate loading capacity of continuous composite slabs, the full scale test on slab specimens with high cost need to be carried out. This paper presented an analytical model for calculating the ultimate loading capacity of continuous composite slabs. Only the small-scale slide block test needed to be carried out for determining some mechanical parameters, resulting in less cost, compared with the conventional m-k test method. Various load conditions and parameters were considered in the analytical model. The comparison between test results and predicted results showed that the proposed method had enough precision. Furthermore, the simplified method was also proposed for practical design.展开更多
Head-splitting is a prevalent physiological disorder in cabbage that causes substantial economic losses.However,the genetic factors and molecular mechanisms underlying head-splitting resistance remain largely unexplor...Head-splitting is a prevalent physiological disorder in cabbage that causes substantial economic losses.However,the genetic factors and molecular mechanisms underlying head-splitting resistance remain largely unexplored.This study identified a genomic region(q NLQ3.1) for head-splitting resistance on chromosome C03 through the combination of QTLseq and GPS analysis in an F_(2) population derived from hybridizing two cabbage inbred lines,‘Dazhengfu'(ZF,susceptible) and ‘103'(resistant).Traditional genetic linkage analysis narrowed q NLQ3.1 to a 74.6 kb region.Furthermore,comparative analysis of the two parental lines using transcriptomic and metabolic profiling demonstrated the crucial role of hormones in regulating head-splitting resistance.Bol028000,encoding a homologue of Arabidopsis Cytokinin Response Factor 3(CRF3),emerged as a promising candidate for head-splitting resistance and was subsequently validated through Sanger sequencing and quantitative RT-PCR(qRT-PCR).Subcellular localisation analysis revealed that Bol028000 was mainly expressed in the nucleus.Additionally,one kompetitive allele-specific PCR(KASP) marker from Bol028000 was developed and utilized to screen 42 inbred lines.These findings enhance the theoretical understanding of head-splitting resistance and provide valuable insights for the molecular breeding of head-splitting resistant cabbages.展开更多
In real industrial microgrids(MGs),the length of the primary delivery feeder to the connection point of the main substation is sometimes long.This reduces the power factor and increases reactive power absorption along...In real industrial microgrids(MGs),the length of the primary delivery feeder to the connection point of the main substation is sometimes long.This reduces the power factor and increases reactive power absorption along the primary delivery feeder from the external network.Besides,the giant induction electro-motors as the working horse of industries requires remarkable amounts of reactive power for electro-mechanical energy conversions.To reduce power losses and operating costs of the MG as well as to improve the voltage quality,this study aims at providing an insightful model for optimal placement and sizing of reactive power compensation capacitors in an industrial MG.In the presented model,the objective function considers voltage profile and network power factor improvement at the MG connection point.Also,it realizes power flow equations within which all operational security constraints are considered.Various reactive power compensation strategies including distributed group compensation,centralized compensation at the main substation,and distributed compensation along the primary delivery feeder are scrutinized.A real industrial MG,say as Urmia Petrochemical plant,is considered in numerical validations.The obtained results in each scenario are discussed in depth.As seen,the best performance is obtained when the optimal location and sizing of capacitors are simultaneously determined at the main buses of the industrial plants,at the main substation of the MG,and alongside the primary delivery feeder.In this way,74.81%improvement in power losses reduction,1.3%lower active power import from the main grid,23.5%improvement in power factor,and 37.5%improvement in network voltage deviation summation are seen in this case compared to the base case.展开更多
Synthetic phenolic antioxidants(SPAs)are widely used in diverse industries due to their exceptional antioxidant characteristics.However,human exposure to SPAs may cause health problems.In this study,226 dust samples w...Synthetic phenolic antioxidants(SPAs)are widely used in diverse industries due to their exceptional antioxidant characteristics.However,human exposure to SPAs may cause health problems.In this study,226 dust samples were collected from 10 provinces in China,and six SPAs(three parent SPAs and their three transformation products)were analyzed.The concentrations of6SPAs(the sum of six target compounds)ranged from 15.4 to 3210 ng/g(geometric mean(GM):169 ng/g).The highest concentration of6SPAswas found in Sichuan Province(GM:349 ng/g),which was approximately 4 times higher than that in Hubei Province(81.6 ng/g)(p<0.05).The concentrations of butylated hydroxytoluene(BHT),2,2'-methylene bis(4-methyl-6–tert-butylphenol)(AO2246),2,6-di–tert–butyl–1,4-benzoquinone(BHT-Q),2,6-di–tert–butyl–4-(hydroxymethyl)phenol(BHT-OH),and ∑_(p)-SPAs were substantially higher in dust from urban areas than rural areas(p<0.05).AO2246 concentration in dust from homes(GM:0.400 ng/g)was about 4 times higher than that in workplaces(0.116 ng/g)(p<0.01).Significantly higherp-SPAs concentrations were found in dust from homes(GM:17.5 ng/g)than workplaces(11.4 ng/g)(p<0.01).The estimated daily intakes(EDIs)of ∑_(6)SPAs exposed through dust ingestion were 0.582,0.342,0.197,0.076,and 0.080 ng/kg bw/day in different age groups,and exposed through dermal contact was 0.358,0.252,0.174,0.167,and 0.177 ng/kg bw/day.EDIs showed that the exposure risks of SPAs decreased with age.This is the first work to determine SPAs in dust from10 provinces in China and investigate the spatial distribution of SPAs in those regions.展开更多
Objective:Triple-negative breast cancer(TNBC)is a highly aggressive subtype that lacks targeted therapies,leading to a poorer prognosis.However,some patients achieve long-term recurrence-free survival(RFS),offering va...Objective:Triple-negative breast cancer(TNBC)is a highly aggressive subtype that lacks targeted therapies,leading to a poorer prognosis.However,some patients achieve long-term recurrence-free survival(RFS),offering valuable insights into tumor biology and potential treatment strategies.Methods:We conducted a comprehensive multi-omics analysis of 132 patients with American Joint Committee on Cancer(AJCC)stage III TNBC,comprising 36 long-term survivors(RFS≥8 years),62 moderate-term survivors(RFS:3-8 years),and 34 short-term survivors(RFS<3 years).Analyses investigated clinicopathological factors,whole-exome sequencing,germline mutations,copy number alterations(CNAs),RNA sequences,and metabolomic profiles.Results:Long-term survivors exhibited fewer metastatic regional lymph nodes,along with tumors showing reduced stromal fibrosis and lower Ki67 index.Molecularly,these tumors exhibited multiple alterations in genes related to homologous recombination repair,with higher frequencies of germline mutations and somatic CNAs.Additionally,tumors from long-term survivors demonstrated significant downregulation of the RTK-RAS signaling pathway.Metabolomic profiling revealed decreased levels of lipids and carbohydrate,particularly those involved in glycerophospholipid,fructose,and mannose metabolism,in long-term survival group.Multivariate Cox analysis identified fibrosis[hazard ratio(HR):12.70,95%confidence interval(95%CI):2.19-73.54,P=0.005]and RAC1copy number loss/deletion(HR:0.22,95%CI:0.06-0.83,P=0.026)as independent predictors of RFS.Higher fructose/mannose metabolism was associated with worse overall survival(HR:1.30,95%CI:1.01-1.68,P=0.045).Our findings emphasize the association between biological determinants and prolonged survival in patients with TNBC.Conclusions:Our study systematically identified the key molecular and metabolic features associated with prolonged survival in AJCC stage III TNBC,suggesting potential therapeutic targets to improve patient outcomes.展开更多
Laser twin-arc GTAW(LTA-GTAW)process has been developed by using the synergic interaction effects of laser and a coupled arc in a weld pool to achieve higher energy efficiency.In this study,bead-on-plate welding was c...Laser twin-arc GTAW(LTA-GTAW)process has been developed by using the synergic interaction effects of laser and a coupled arc in a weld pool to achieve higher energy efficiency.In this study,bead-on-plate welding was conducted on 8-mm-thick Q235B work-pieces to investigate the variation of hybrid arc profile,the influence of hybrid arc profile on weld forming,microstructure and mech-anical properties of the joint during the LTA-GTAW process.The influence of Laser-GTAW and LTA-GTAW methods on weld surface appearance,heat input per unit length,and weld metal microstructure were also demonstrated systematically.The LTA-GTAW can make the distribution of arc energy more reasonable in welding depth and width.When defocus is 0,I_(f)is 330 A,I_(b)is 240 A,laser power is 2.4 kW,and spacing between heat sources of tungsten electrode is 10 mm,the weld shape is better.Compared with Laser-GTAW,LTA-GTAW can achieve lower heat input at the same penetration depth,and the microstructure of the weld is refined.The tensile strength of the welded joint is 121.8%of the base material,and the fracture mode of the welded joint is ductile fracture,the comprehensive mechanical properties are better.展开更多
This research aimed to overcome challenges such as high costs,lengthy optimization time,and low efficiency in resolving issues related to wheel-rail contact,rail wear,and vehicle dynamics.Based on the wheel-rail conta...This research aimed to overcome challenges such as high costs,lengthy optimization time,and low efficiency in resolving issues related to wheel-rail contact,rail wear,and vehicle dynamics.Based on the wheel-rail contact parameters,an optimal design method for rail grinding target profile is proposed from wear profile measurement to grinding profile design according to the actual railway track and vehicle operating conditions.We utilized Isight to create a simulation test and developed an RBF proxy model that incorporated both mechanical and geometric aspects of wheel-rail contact.By integrating rail modeling,wheel-rail contact analysis,and multi-objective optimization,we established a rail grinding optimization model that was solved using the NSGA-II algorithm.After optimization,the study achieved a 31.863%reduction in average contact stress,a 70.5%reduction in matching wear work,and a 100.391%increase in the difference in rolling radius between the wheel and rail.展开更多
In this paper,a double-effect DNN-based Digital Back-Propagation(DBP)scheme is proposed and studied to achieve the Integrated Communication and Sensing(ICS)ability,which can not only realize nonlinear damage mitigatio...In this paper,a double-effect DNN-based Digital Back-Propagation(DBP)scheme is proposed and studied to achieve the Integrated Communication and Sensing(ICS)ability,which can not only realize nonlinear damage mitigation but also monitor the optical power and dispersion profile over multi-span links.The link status information can be extracted by the characteristics of the learned optical fiber parameters without any other measuring instruments.The efficiency and feasibility of this method have been investigated in different fiber link conditions,including various launch power,transmission distance,and the location and the amount of the abnormal losses.A good monitoring performance can be obtained while the launch optical power is 2 dBm which does not affect the normal operation of the optical communication system and the step size of DBP is 20 km which can provide a better distance resolution.This scheme successfully detects the location of single or multiple optical attenuators in long-distance multi-span fiber links,including different abnormal losses of 2 dB,4 dB,and 6 dB in 360 km and serval combinations of abnormal losses of(1 dB,5 dB),(3 dB,3 dB),(5 dB,1 dB)in 360 km and 760 km.Meanwhile,the transfer relationship of the estimated coefficient values with different step sizes is further investigated to reduce the complexity of the fiber nonlinear damage compensation.These results provide an attractive approach for precisely sensing the optical fiber link status information and making correct strategies timely to ensure optical communication system operations.展开更多
基金the National Natural Science Foundation of China(No.52275378)the National Key Laboratory for Precision Hot Processing of Metals(6142909200208)。
文摘The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficiency and low-cost manufacturing of the component.Blank design is the key part of plastic forming process design.For spinning-rolling process,the shape and size of the blank play a crucial role in process stability,deformation behavior and dimensional accuracy.So this work proposes a blank design method to determine the geometry structure and sizes of the blank.The mathematical model for calculating the blank size has been deduced based on volume conservation and neutral layer length invariance principle.The FE simulation and corresponding trial production of an actual big-tapered profiled ring disk show that the proposed blank design method is applicative.In order to obtain a preferred blank,the influence rules of blank size determined by different deformation degrees(rolling ratio k)on the spinning-rolling process are revealed by comprehensive FE simulations.Overall considering the process stability,circularity of the deformed ring disk and forming forces,a reasonable range of deformation degree(rolling ratio k)is recommended for the blank design of the new spinning-rolling process.
基金the National Natural Science Foundation of China(Nos.51905234,51805231,51975264,51905275,51705463)。
文摘Profiled monolayer cBN wheel was induction brazed for grinding of titanium dovetail slot in this study.Aimed at acquiring a uniform temperature distribution along the profiled surface and reducing the thermal deformation of the brazed wheel,a finite element model was established to investigate the temperature uniformity during induction brazing.A suitable induction coil and the related working parameters were designed and chosen based on the simulation results.Ag-Cu-Ti alloy and cBN grains were applied in the induction brazing experiment.The results showed geometric deformation of the brazed wheel was no more than 0.01 mm and chemical reaction layer were found on the brazed joint interface.Further validation tests were carried out by grinding of Ti-6 Al-4 V alloy.Compared to the electroplated wheel,the brazed wheel showed better performance such as low specific grinding energy and good ground quality in grinding of Ti-6 Al-4 V alloy.Abrasion wear was found to be the main failure mode for the induction brazed wheel,while adhesion and grains pull-out were the main failure mode for the electroplated wheel.
基金supported by Recruitment program of Global Youth Expert of China (to X.G.)the Elite Youth Program of the Chinese Academy of Agricultural Science (to X.G.)the intramural research support from Biotechnology Research Institute, Chinese Academy of Agricultural Sciences
文摘The most common and abundant DNA modification is 5-methylcytosine（5mC）,which has been well-established as an epigenetic mark regulating gene expression in eukaryotes（Jones,2012）.Another DNA modification N^6-methyldeoxyadenosine（6mA）,previously reported as a widespread DNA methylation in prokaryotes.
基金the National Natural Science Foundation of China(52275378).
文摘The final quality of complex conical-section rings depends on co-design of multiple processes in forming process chain.In this study,for a complex aeroengine casing ring with a large slope and a flange on its end,a co-design method of the forming process chain is put forward towards the objective of precision forming,which not only proposes a standard process route composed of multiple processes of upsetting,punching,rectangular ring rolling,loose tooling forging and profiled ring rolling,but also presents co-design methods of dies and blanks for all the processes.For profiled ring rolling,a design method of preformed blank that makes the blank and the target conical-section ring have the same axial volume distribution is proposed.By the method,the axial metal redistribution during the process can be alleviated greatly thus improving the forming stability and precision of the ring.Based on the geometric features of designed preformed blank,design methods of blanks and dies for loose tolling forging,rectangular ring rolling,punching and upsetting are proposed sequentially.In view of the key roles of loose tooling forging(manufacturing the preformed blank)and profiled ring rolling on the final quality of the conical ring parts,inherited FE simulations for these two processes are performed to verify the proposed design methods and determine appropriate design parameter.It is demonstrated that the proposed design method has significant advantages in improving forming precision.Besides,a suggestive value 1.5 of the rolling ratio for profiled ring rolling(a key design parameter)is given based on comprehensive consideration of multiple indicators such as ring roundness,deformation uniformity and forming load.The corresponding industrial experiments performed illustrate that a high forming precision of the conical-section aeroengine casing ring is achieved.
基金Key R&D Program of China(No.20I7YFB0306404)Natural Science Foundation of Hebei Province(No.E2016203179)Postdoctoral Science Foundation of China(No.2016M590211).
文摘An an alytical model based on linear decreasi ng leveli ng scheme was proposed to inv estigate the longitu din ally profiled plate leveling process.Considering the variable cross-sectional thickness of longitudinally profiled plate and the dynamic reductions in leveling rolls,the reduction models of upper and lower rolls,the leveling force model and the leveling moment model were established,respectively,based on linear decreasing leveling scheme.Moreover,the finite element model of longitudinally profiled plate leveling process was established based on ABAQUS.Then,the total displacements of upper and lower rolls,the leveling force and the stress distribution of longifudinally profiled plate in the leveling process were calculated.To verify the validity of the proposed models,calculated leveling forces were compared with the measured values,and very good agreements are found.Calculated results show that linear decreasing leveling scheme is suitable for leveling longitudinally profiled plate.
基金Supported by the National Natural Science Foundation of China(No.52376021).
文摘How to utilize existing flow control mechanisms to make profiled end wall design more flexible,efficient,and physical is a meaningful challenge.This study presents a three-dimensional inverse method for profiled end wall design to achieve the application of flow control mechanisms.The predetermined pressure distribution on the end wall is reached by modifying the end wall geometry during flow field calculation.A motion velocity model is derived from the normal momentum equation of the moving no-slip boundary to modify the end wall geometry.A Reynolds-Averaged Navier-Stokes(RANS)solver based on the Semi-Implicit Method for Pressure Linked Equations(SIMPLE)algorithm is adopted to simulate the flow field.Based on the mechanism understanding obtained through numerical optimization results,this study adopts the inverse method to redesign an optimized end wall in a compressor cascade.The results indicate that the redesigned end wall exhibits better loss reduction,reducing the overall total pressure loss by 5.5%,whereas the optimized end wall reduces it by 3%.The inverse method allows the imposition of desired influences on the end wall flow without constructing a database,making it highly flexible,efficient,and physical.
基金The authors are grateful for the supports of the National Key Research and Development Program of China(No.2017YFB0306404)Key Project of Hebei Education Department(No.ZD2018203).
文摘Considering the variable cross section thickness of longitudinal profiled plate and the dynamic reductions of straightening rolls,an analytical model combining curvature integral method with linear decreasing straightening scheme was proposed to investigate the longitudinal profiled plate straightening process.Moreover,the calculation flow and solution algorithm of longitudinal profiled plate straightening process were presented.To verify the proposed model,calculated straightening forces were compared with the measured values,and very good agreements were achieved.Then,the reduction,contact angle,reverse bending curvature,residual curvature,straightening force and straightening moment of longitudinal profiled plate in the straightening process were calculated and analyzed,and the calculated results show that the curvature integral method can be used to reveal the mechanism of longitudinal profiled plate straightening.
基金Foundation for the Author of National Excellent Doctoral Dissertation of P.R.China(No.200350)
文摘A multi-shape representation approach for measuring geometrical properties of profiled fibers was presented.From closed edge chains of a fiber cross section,three evenly spaced vertices were selected to form a triangle by changing the vertices' spacing,or the step length,the Triangle Area Representation(TAR)was calculated with a special determinant.The bend direction of the two consecutive lines drawn by three vertices determined the sign of the TAR.TARN and TARP were negative and positive extensions of TAR,and used to analyze concave and convex segments on the boundary.The length of TARN measured the size of concaveness.Multi-scale TARPs together with TARN can help to detect fiber conglutinations.
文摘The key technique of a kinetic energy rod(KER) warhead is to control the flight attitude of rods. The rods are usually designed to different shapes. A new conceptual KER named profiled rod which has large L/D ratio is described in this paper. The elastic dynamic equations of this profiled rod flying at high velocity after detonation are set up on the basis of Euler-Bernoulli beam, and the aeroelastic deformation of profiled rod is calculated by semi-analytical method for calculating the vibration characteristics of variable cross-section beam. In addition, the aeroelastic deformation of the undeformed profiled rod and the aeroelastic deformation of deformed profiled rod which is caused by the detonation of explosive are simulated by computational fluid dynamic and finite element method(CFD/FEM), respectively. A satisfactory agreement of these two methods is obtained by the comparison of two methods. The results show that the semi-analytical method for calculating the vibration characteristics of variable cross-section beam is applied to analyze the aeroelastic deformation of profiled rod flying at high velocity.
基金The research was financially supported by the National Natural Science Foundation of China(Grant Nos.51674222 and 51974278)Yanshan University(15LGAOO3).
文摘Longitude profiled cladded sheet is obtained by rolling bimetal cladded sheet with variable gauge rolling technology.The longitude profiled rolling process of Cu/Al cladded sheets was studied by finite element method and experiments.The rolling force rises with the increase in reduction,and a sudden change appears at the end of the thickness variation zone.The thickness ratio of copper layer is enlarged after rolling owing to its relatively large deformation resistance and continues to rise with the increase in reduction rate.Lower elongation of copper side leads to the warpage of exit metal to copper side,which further hinders the deformation of copper.The influence of asymmetric rolling parameters indicates that increasing the work roll diameter ratio,speed radio,and friction coefficient on Al side can reduce the warpage when the reduction rate is below a certain value depending on the thickness ratio and other rolling parameters.Comparison of experiments and simulation results showed good agreement and verified the finite element model.
基金Sponsored by the CALT University Joint Fund(Grant No.CALT201105)
文摘A new Kinetic Energy Rod( KER) warhead named profiled rod warhead is proposed in this paper.Based on the design of profiled rod warhead,a model of profiled rod driven by detonation is established. The detonation process is simulated by ANSYS / LS-DYNA,and the deployment velocity and initial flight attitude of rod are achieved. In addition,static rod deployment testing are performed to investigate the damage effect,the spatial flight attitude and deployment velocity. A satisfactory agreement is obtained by the comparison between numerical results and testing results. Meanwhile,the profiled rod studies are conducted to determine a higher penetrability compared with traditional cylindrical rods. Rigid body dynamics equations of profiled rod,which accounts for the influence of air resistance,are set up to predict the flight trajectory of long-distance. The results show that the profiled rod may provide a better penetration angle which still maintains a significant penetrability against projectiles when the rods move off long-distance range.
文摘In order to achieve a lower consumed energy, the performance of a new type of rotating volumetric pump with two profiled rotors (variant I) which is compared with a centrifugal pump (variant II) is presented. The analysis regarding the same flow rate of transported liquid and the same pressure increases points out the conduct of the system at the variation of the key operating parameters. The actual driving power of the rotating volumetric pump is higher stating that is more advantageous in operation. The effective efficiency of the system is improved due to the original constructive solution.
文摘Composite slabs with profiled steel sheet are widely applied in practical structures now. Plenty of literatures can be available about simply supported composite slabs with single span. However, continuous slabs always exist in high-rise building structures. In order to obtain the ultimate loading capacity of continuous composite slabs, the full scale test on slab specimens with high cost need to be carried out. This paper presented an analytical model for calculating the ultimate loading capacity of continuous composite slabs. Only the small-scale slide block test needed to be carried out for determining some mechanical parameters, resulting in less cost, compared with the conventional m-k test method. Various load conditions and parameters were considered in the analytical model. The comparison between test results and predicted results showed that the proposed method had enough precision. Furthermore, the simplified method was also proposed for practical design.
基金funded by the Agricultural Development Program through Science and Technology of Shanghai,China (2022-02-08-00-12-F01099)the National Key R&D Program of China (2023YFD1201501)+1 种基金the Science and Technology Commission of Shanghai Municipality,China (22DX1900100)the Excellent Team Project of Shanghai Academy of Agricultural Sciences,China (2022(007))。
文摘Head-splitting is a prevalent physiological disorder in cabbage that causes substantial economic losses.However,the genetic factors and molecular mechanisms underlying head-splitting resistance remain largely unexplored.This study identified a genomic region(q NLQ3.1) for head-splitting resistance on chromosome C03 through the combination of QTLseq and GPS analysis in an F_(2) population derived from hybridizing two cabbage inbred lines,‘Dazhengfu'(ZF,susceptible) and ‘103'(resistant).Traditional genetic linkage analysis narrowed q NLQ3.1 to a 74.6 kb region.Furthermore,comparative analysis of the two parental lines using transcriptomic and metabolic profiling demonstrated the crucial role of hormones in regulating head-splitting resistance.Bol028000,encoding a homologue of Arabidopsis Cytokinin Response Factor 3(CRF3),emerged as a promising candidate for head-splitting resistance and was subsequently validated through Sanger sequencing and quantitative RT-PCR(qRT-PCR).Subcellular localisation analysis revealed that Bol028000 was mainly expressed in the nucleus.Additionally,one kompetitive allele-specific PCR(KASP) marker from Bol028000 was developed and utilized to screen 42 inbred lines.These findings enhance the theoretical understanding of head-splitting resistance and provide valuable insights for the molecular breeding of head-splitting resistant cabbages.
文摘In real industrial microgrids(MGs),the length of the primary delivery feeder to the connection point of the main substation is sometimes long.This reduces the power factor and increases reactive power absorption along the primary delivery feeder from the external network.Besides,the giant induction electro-motors as the working horse of industries requires remarkable amounts of reactive power for electro-mechanical energy conversions.To reduce power losses and operating costs of the MG as well as to improve the voltage quality,this study aims at providing an insightful model for optimal placement and sizing of reactive power compensation capacitors in an industrial MG.In the presented model,the objective function considers voltage profile and network power factor improvement at the MG connection point.Also,it realizes power flow equations within which all operational security constraints are considered.Various reactive power compensation strategies including distributed group compensation,centralized compensation at the main substation,and distributed compensation along the primary delivery feeder are scrutinized.A real industrial MG,say as Urmia Petrochemical plant,is considered in numerical validations.The obtained results in each scenario are discussed in depth.As seen,the best performance is obtained when the optimal location and sizing of capacitors are simultaneously determined at the main buses of the industrial plants,at the main substation of the MG,and alongside the primary delivery feeder.In this way,74.81%improvement in power losses reduction,1.3%lower active power import from the main grid,23.5%improvement in power factor,and 37.5%improvement in network voltage deviation summation are seen in this case compared to the base case.
基金supported by the National Key Research and Development Program of China(No.2023YFC3706602)the National Natural Science Foundation of China(Nos.22225605 and 22193051)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0750200).
文摘Synthetic phenolic antioxidants(SPAs)are widely used in diverse industries due to their exceptional antioxidant characteristics.However,human exposure to SPAs may cause health problems.In this study,226 dust samples were collected from 10 provinces in China,and six SPAs(three parent SPAs and their three transformation products)were analyzed.The concentrations of6SPAs(the sum of six target compounds)ranged from 15.4 to 3210 ng/g(geometric mean(GM):169 ng/g).The highest concentration of6SPAswas found in Sichuan Province(GM:349 ng/g),which was approximately 4 times higher than that in Hubei Province(81.6 ng/g)(p<0.05).The concentrations of butylated hydroxytoluene(BHT),2,2'-methylene bis(4-methyl-6–tert-butylphenol)(AO2246),2,6-di–tert–butyl–1,4-benzoquinone(BHT-Q),2,6-di–tert–butyl–4-(hydroxymethyl)phenol(BHT-OH),and ∑_(p)-SPAs were substantially higher in dust from urban areas than rural areas(p<0.05).AO2246 concentration in dust from homes(GM:0.400 ng/g)was about 4 times higher than that in workplaces(0.116 ng/g)(p<0.01).Significantly higherp-SPAs concentrations were found in dust from homes(GM:17.5 ng/g)than workplaces(11.4 ng/g)(p<0.01).The estimated daily intakes(EDIs)of ∑_(6)SPAs exposed through dust ingestion were 0.582,0.342,0.197,0.076,and 0.080 ng/kg bw/day in different age groups,and exposed through dermal contact was 0.358,0.252,0.174,0.167,and 0.177 ng/kg bw/day.EDIs showed that the exposure risks of SPAs decreased with age.This is the first work to determine SPAs in dust from10 provinces in China and investigate the spatial distribution of SPAs in those regions.
基金supported by grants from the Medical Engineering Jiont Fund of the Fudan University(No.IDH2310117)。
文摘Objective:Triple-negative breast cancer(TNBC)is a highly aggressive subtype that lacks targeted therapies,leading to a poorer prognosis.However,some patients achieve long-term recurrence-free survival(RFS),offering valuable insights into tumor biology and potential treatment strategies.Methods:We conducted a comprehensive multi-omics analysis of 132 patients with American Joint Committee on Cancer(AJCC)stage III TNBC,comprising 36 long-term survivors(RFS≥8 years),62 moderate-term survivors(RFS:3-8 years),and 34 short-term survivors(RFS<3 years).Analyses investigated clinicopathological factors,whole-exome sequencing,germline mutations,copy number alterations(CNAs),RNA sequences,and metabolomic profiles.Results:Long-term survivors exhibited fewer metastatic regional lymph nodes,along with tumors showing reduced stromal fibrosis and lower Ki67 index.Molecularly,these tumors exhibited multiple alterations in genes related to homologous recombination repair,with higher frequencies of germline mutations and somatic CNAs.Additionally,tumors from long-term survivors demonstrated significant downregulation of the RTK-RAS signaling pathway.Metabolomic profiling revealed decreased levels of lipids and carbohydrate,particularly those involved in glycerophospholipid,fructose,and mannose metabolism,in long-term survival group.Multivariate Cox analysis identified fibrosis[hazard ratio(HR):12.70,95%confidence interval(95%CI):2.19-73.54,P=0.005]and RAC1copy number loss/deletion(HR:0.22,95%CI:0.06-0.83,P=0.026)as independent predictors of RFS.Higher fructose/mannose metabolism was associated with worse overall survival(HR:1.30,95%CI:1.01-1.68,P=0.045).Our findings emphasize the association between biological determinants and prolonged survival in patients with TNBC.Conclusions:Our study systematically identified the key molecular and metabolic features associated with prolonged survival in AJCC stage III TNBC,suggesting potential therapeutic targets to improve patient outcomes.
基金supported by the Industrial Innovation Major Technology Global Unveiling Project of Jining City(2022JBZP004)Taishan Scholars Project.
文摘Laser twin-arc GTAW(LTA-GTAW)process has been developed by using the synergic interaction effects of laser and a coupled arc in a weld pool to achieve higher energy efficiency.In this study,bead-on-plate welding was conducted on 8-mm-thick Q235B work-pieces to investigate the variation of hybrid arc profile,the influence of hybrid arc profile on weld forming,microstructure and mech-anical properties of the joint during the LTA-GTAW process.The influence of Laser-GTAW and LTA-GTAW methods on weld surface appearance,heat input per unit length,and weld metal microstructure were also demonstrated systematically.The LTA-GTAW can make the distribution of arc energy more reasonable in welding depth and width.When defocus is 0,I_(f)is 330 A,I_(b)is 240 A,laser power is 2.4 kW,and spacing between heat sources of tungsten electrode is 10 mm,the weld shape is better.Compared with Laser-GTAW,LTA-GTAW can achieve lower heat input at the same penetration depth,and the microstructure of the weld is refined.The tensile strength of the welded joint is 121.8%of the base material,and the fracture mode of the welded joint is ductile fracture,the comprehensive mechanical properties are better.
基金Supported by Fundamental Research Funds for the Central Universities(Grant No.2019JBM050).
文摘This research aimed to overcome challenges such as high costs,lengthy optimization time,and low efficiency in resolving issues related to wheel-rail contact,rail wear,and vehicle dynamics.Based on the wheel-rail contact parameters,an optimal design method for rail grinding target profile is proposed from wear profile measurement to grinding profile design according to the actual railway track and vehicle operating conditions.We utilized Isight to create a simulation test and developed an RBF proxy model that incorporated both mechanical and geometric aspects of wheel-rail contact.By integrating rail modeling,wheel-rail contact analysis,and multi-objective optimization,we established a rail grinding optimization model that was solved using the NSGA-II algorithm.After optimization,the study achieved a 31.863%reduction in average contact stress,a 70.5%reduction in matching wear work,and a 100.391%increase in the difference in rolling radius between the wheel and rail.
基金supported by the National Key Research and Development Program of China (2019YFB1803905)the National Natural Science Foundation of China (No.62171022)+2 种基金Beijing Natural Science Foundation (4222009)Guangdong Basic and Applied Basic Research Foundation (2021B1515120057)the Scientific and Technological Innovation Foundation of Shunde Graduate School,USTB (No.BK19AF005)。
文摘In this paper,a double-effect DNN-based Digital Back-Propagation(DBP)scheme is proposed and studied to achieve the Integrated Communication and Sensing(ICS)ability,which can not only realize nonlinear damage mitigation but also monitor the optical power and dispersion profile over multi-span links.The link status information can be extracted by the characteristics of the learned optical fiber parameters without any other measuring instruments.The efficiency and feasibility of this method have been investigated in different fiber link conditions,including various launch power,transmission distance,and the location and the amount of the abnormal losses.A good monitoring performance can be obtained while the launch optical power is 2 dBm which does not affect the normal operation of the optical communication system and the step size of DBP is 20 km which can provide a better distance resolution.This scheme successfully detects the location of single or multiple optical attenuators in long-distance multi-span fiber links,including different abnormal losses of 2 dB,4 dB,and 6 dB in 360 km and serval combinations of abnormal losses of(1 dB,5 dB),(3 dB,3 dB),(5 dB,1 dB)in 360 km and 760 km.Meanwhile,the transfer relationship of the estimated coefficient values with different step sizes is further investigated to reduce the complexity of the fiber nonlinear damage compensation.These results provide an attractive approach for precisely sensing the optical fiber link status information and making correct strategies timely to ensure optical communication system operations.
