最新刊期
卷 33 ， 期 10 ， 2013
- 摘要：The rheological behavior of 2124aluminum alloy during isothermal compression processes was analyzed.The flow stress-strain relationship was described by hyperbolic sine constitutive equation.Based on dynamic material model,processing maps were constructed.The results show that compression process is characterized by steady-state flow.The flow stress is decreased with the increase of deformation temperature or increased with the increase of strain rate.The processing maps show that flow instability area become larger with the deformation increase.The optimum processing parameters for the alloy are presented as follows:deformation temperature at 460480℃and strain rate of 0.010.1s-1.关键词：2124 Aluminum Alloy;Hot Deformation;Constitutive Equation;Processing Map
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发布时间：2023-12-18 - 摘要：Carbon nanotubes（CNTs）reinforced AZ91Dmagnesium matrix nanocomposites were fabricated by mechanical stirring combined with ultrasonic vibration dispersion.Microstructure and mechanical properties of CNTs/AZ91Dcomposites were investigated by optical metallographic microscope（OM）,scanning electronic microscope（SEM）and tensile test,and fracture morphology of the tensile samples was also observed by SEM and energy spectrum analysis（EDS）.The results show that carbon nanotubes can be added smoothly and distributed dispersedly in the AZ91D magnesium matrix alloy by the semi-solid mechanical stirring and high-energy ultrasonic treatment.When CNTs addition is in range of01.0 %,with the increase of CNTs content,tensile strength and elongation of the composites prepared are improved obviously.Tensile strength,yield strength and elongation of 1.0% CNTs/AZ91D magnesium matrix composites reach 200MPa,114MPa and 5.4%,respectively,compared with those of matrix alloy,increased by 51.5%,42.5%and by 170%,respectively,showing excellent comprehensive mechanical properties.Carbon nanotubes mainly play the role in refining grains of the nanocomposites and bearing deformation loading.关键词：Magnesium Matrix Composites;Ultrasonic Processing;Microstructure;Mechanical Properties
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发布时间：2023-12-18 - 摘要：K4169superalloy with different Cu contents from 0to 0.5%（weight percentage）was prepared by a manual electric arc furnace.The phase composition,solidification structure,segregation and the melting point of the superalloy prepared were observed by XRD（X-ray diffraction）,OM（optical microscope）,SEM（scanning electron microscope）,SEM-EDS and DSC.The results show that Cu is negative segregation element which mainly enriched at the dendrite arm,and it promotes the segregation of Nb,Mo and Fe,meanwhile,Cu promotes significantly the precipitation of Laves phase and MC carbide at the grain boundaries.In addition,the incipient melting temperature of Laves phase and the melting point of alloy are decreased with the Cu addition.The analysis shows that Cu is harmful to the solidification structure of K4169superalloy.关键词：K4169 Superalloy;Copper;Solidification Structure;Element Segregation;Laves Phase
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发布时间：2023-12-18 - 摘要：Effects of solution temperature on microstructure and corrosion resistance of hyper duplex stainless steel contained 0.51% and 0.72%N were investigated.And the corrosion resistance of hyper duplex stainless steel compared with super duplex stailess 2906were analyzed.The results show that hyper duplex stainless steel containing 0.51%N is composed of ferrite phase and austenite phase with the solution treatment temperature in 1 1701 220℃.γ2precipitates can be observed in hyper duplex stainless steel with 0.72%N at 1 170℃.As the solution treatment temperature increased to 1 200℃and to1 220℃,γ2precipitates are dissolved.Hyper duplex stainless steel containing 0.51%N and 0.72% N exhibits excellent corrosion resistance with the solution treatment temperature of 1 200 ℃.γ2precipitates are susceptible to corrosion.The corrosion resistance of hyper duplex stainless steel with 0.72%Nγ2is superior-to that of ones with 0.51%N,Corrosion resistance of 2906steel is the worst.关键词：Hyper Duplex Stainless Steel;Solution Temperature;γ2Phase;Corrosion Resistance
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发布时间：2023-12-18 - 摘要：Because of the short procedure,high product quality and near zero pollution,multistage continuous heat-type vacuum furnace is widely used in the separation of binary alloys.However,it is difficult to measure temperature in vacuum furnace,and temperature control level is low with low efficiency.Meanwhile,many problems in vacuum furnace temperature field can not be understood deeply.Using simulation to calculate temperature at each node in vacuum furnace,it is very important to separate different alloys.Finite element analysis was used to understand temperature field in multistage continuous vacuum heat furnace,and temperature field distribution was simulated by the ANSYS software for vacuum furnace in the continuous heating furnace to present simulation distribution map of non-steady temperature field in the furnace with charge free.Through an experimental test,the actual temperature value at the primary node in the chamber was given.Through comparison with the simulation value,the maximum error is below 4.2%at a given node.关键词：Temperature Field;Finite Element Analysis;ANSYS Software;Binary Alloys;Vacuum
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发布时间：2023-12-18 - 摘要：Effects of Nd or C2Cl6modification and Nd and C2Cl6compound modification on the microstructure and mechanical properties of AZ91magnesium alloy were investigated by tensile testing,OM（optical microscopy）,SEM（scanning electron microcopy）,XRD（X-ray diffraction）and TEM（transmission electron microscopy）.The results show that the three modification ways can refine the microstructure and improve properties of the AZ91magnesium.Nd exhibits the most desirable effects,and then C2Cl6,while Nd and C2Cl6composite inoculation exhibits the worst.关键词：Microstructure;Mechanical Properties;Nd;C2Cl6
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发布时间：2023-12-18 - 摘要：Effects of processing parameters on surface quality and solidification structure of pure aluminum slab which was prepared by continuous unidirectional solidification device（OCC）were analyzed.Meanwhile,factors influencing crack generation of the slab were analyzed.The results show that pure aluminum slab with good surface quality and continuous columnar crystals can be prepared under the conditions of drawing speed of 5mm/min,cooling water of 220L/h,the upper of mold of 694℃,outlet of mold of 668℃.The surface defects of pure aluminum plate prepared by the method include mainly surface transverse cracks and corner transverse cracks with length ranging from 10mm to 30mm and maximum depth up to 4mm.The distribution mode of the surface transverse cracks exhibits axial,radial parallel distribution and partial transverse crack.关键词：Pure Aluminum;Plate;Continuous Unidirectional Solidification;Columnar Crystal
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发布时间：2023-12-18 - 摘要：Effects of varied passes,such as 1,2,4,6passes,on loading,temperature,equivalent stress and strain of TC4alloy during equal channel angular extruding process were investigated with Bc path at350℃ by numerical analysis.The results reveal that with increasing in extruding passes,loading applied is increased,and the peak value of loading applied is increased with occurrence time shifted to right.With the increase of temperature,equivalent stress and strain are increased.In addition,the desirable grain refinement can be obtained in the TC4alloy with four passes extrusion.关键词：TC4Titanium Alloy;Extrusion;ECAP
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发布时间：2023-12-18 - 摘要：The metal mold casting process for thin-walled Al alloy shell was designed.The filling flow,temperature field and shrinkage porosity（holes）of metal mold casting thin-walled aluminum alloy shell were simulated to optimize the casting process.The simulation results show that the filling flow exhibits stable with uniform temperature distribution,and the predictable shrinkage cavities and porosity are not observel in the casting.The simulated result indicates that the optimized casting process for thin-walled Al alloy shell is reasonable.Through the rational use of copper-based cold iron to optimize effectively the temperature distribution,the possible shrinkage porosity（holes）in the shell can be reduced or eliminated.关键词：Thin-Walled Al Alloy Casting;Numerical Simulation;Temperature Field;Shrinkage Porosity
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发布时间：2023-12-18 - 摘要：Based on the humanization design principle,through some examples,the positive effects of humanization design in die casting enterprise were expounded from deferent view point,such as manufacturing,operation and design.关键词：Casting Mould;Mould Design;Humanistic Design.
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发布时间：2023-12-18 - 摘要：Low voltage pulsed magnetic field（LVPMF）processing was employed for preparing semi-solid ZL101Aalloy slurry.Effects of discharging frequency on morphology and size of the primary phase in semi-solid ZL101Aalloy slurry were analyzed.The results show that semi-solid ZL101Aalloy slurry with nondendritic structure can be obtained by LVPMF treatment.The primaryα-Al particles exhibit smaller and rounder with the increase of discharging frequency.However,with the discharging frequency increased to 10Hz,the grain size is coarsened slightly,and the roundness is decreased.The semi-solid slurry with primaryα-All particle average diameter of about 91μm and average shape factor of 0.88can be prepared under LVPMF at the pouring temperature of 635℃,discharging voltage of 200V,discharging frequency of 10Hz and the treatment time of 1.5min.关键词：Low Voltage Pulsed Magnetic Field Process;Semi-solid Slurry;ZL101AAlloy;Primaryα-Al
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发布时间：2023-12-18 - 摘要：Influences of liquid temperature and the solid particles radius on the heat transfer behavior in solid state were analyzed by heating steel and Al-10Si alloy semi-solid billet samples.The results reveal that liquid temperature and the solid particles radius have olvious effects on solid-phase heat transfer,and the solid phase particle radius is constrained by the liquid temperature.Solid phase heating state is mainly depended on the heat transfer effect of the temperature field in the solid-liquid two-phase region.关键词：Semi-solid;Liquid Temperature;Solid Particles Radius;Solid-Liquid Interface;Heat Conductivity
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发布时间：2023-12-18 - 摘要：We have developed a forced convection rheoforming machine（FCR）,which mainly is composed of the shearing system and the electricity and temperature control system.Effects of pouring temperatures on microstructure of A356aluminum alloy semi-solid slurry prepared by FCR machine were investigated.The results show that the apparatus is capable of producing semi-solid microstructure with fine,homogeneous and spherical grains with rotating velocity of 200r/min for 30sat 620℃.And the primaryα-Al particles become finer,more homogeneous and rounder with the decrease of pouring temperature.关键词：FCR;Semi-solid;A356Aluminum Alloy;Microstructure
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发布时间：2023-12-18 - 摘要：Zinc alloy worm gears were produced by squeeze casting.The process and defects such as stratification,bubble,crack,were introduced.The origination of these defects was described,and the countermeasures were presented.Meanwhile,the feasibility was verified by the practical production.关键词：Squeezing Casting;ZA27Zinc Alloy Worm Gear;Defect Analysis;Countermeasures
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发布时间：2023-12-18 - 摘要：The Flow-3Dsoftware was employed to optimize the hot-chamber die casting process of die casting Zn alloy zipper head.The simulation results show that detour flow and vortex are formed during molten metal filling the cavity in the initial gating system,and gas-entrapment in parts can be generated.The gas-entrapment position from the simulated result is consistent with the practical product defects,and velocity vector of molten metal flow can be used to explain the formation of vortex.A new gating system was designed,in which the runner and ingate were diverged from sprue.The simulated results show that metal molten flow can not impact the side of the work cavity directly,effectively avoiding vortex flow and eliminating gas-entrapment in the die casting Zn alloy zipper head.关键词：Die Casting Zn Alloy;Numerical Simulation;Gating System;Zipper Head
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发布时间：2023-12-18 - 摘要：Through analyzing structure characteristics of squeeze-casting aluminum alloy wheel,wheel mould was designed,including pouring and exhausting system as well as overflow system.Filling and solidification process of aluminum alloy wheel were simulated,and based on the simulated result,mould design was modified.Meanwhile,product trial was carried out with the modified mould.The results show that mould structure design is reasonable,in which exhausting and overflow system exhibit desirable.Qualified wheel without shrinkage porosity（holes）,gas holes can be observed in the slice analysis.X-ray shows that the wheel quality is superior to I grade ASTM E155.关键词：Aluminum Wheels;Squeeze Casting;Mould Design;Simulation Analysis;X-Ray
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发布时间：2023-12-18 - 摘要：The hollow Al-Zn-Mg-Cu alloy driving hollow shaft was produced by squeeze casting.The macro-crack in the hollow shaft was observed in the process of cooling and demoulding.The origination of crack generation was analyzed.The crack in the hollow shaft is attributed to the different volumetric contraction between the hollow shaft and mould are as well as excessive demoulding foce and crack in the hollow shaft was solved by delayed mould,and the qualified castings were manufactured.关键词：Squeeze Casting;Al-Zn-Mg-Cu Alloy;Hollow Shaft;Crack
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发布时间：2023-12-18 - 摘要：Effects of investment casting on the mechanical properties and microstructure of ZL210Aalloy at as-cast,solid solution and aged state were analyzed,and compared with those in sand mold casting and in metal mold casting.The experimental results show that the grain size of investment casting samples is the more coarse than that of ones in sand mold samples and in metal mold samples regardless of as-cast,solid solution or aged state.The tensile strength and yield strength of investment casting as-cast samples are slightly lower than those in sand mold samples and in metal mold samples,while the elongation is near to that of metal mold samples,however it is higher than that of sand mold samples no matter in as-cast state,solid solution state or aging state.The hardness value of the investment casting samples is higher than that of sand mold samples and metal mold samples.After solid solution,the tensile strenght,yield strenght,elongation and hardness are improved by 1.4、2.0、1.1times and by 1.2times,respectively.After aging treatment,the tensile strength,yield strength and hardness are further improved,increased by 2.2、4.4times and by 2.1times,while the elongation is near to that of as-casting samples with only 9%.关键词：ZL210AAlloy;Mechanical Properties;Sand Mold;Metal Mold;Investment Casting
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发布时间：2023-12-18 - 摘要：High added value investment castings,such as turbine blade for aerospace engine,large complex Ti alloy investment casting,near-net forming thin-walled Al alloy parts,industrial gas turbine blade,tubocharge for acr engine,were reviewed.Now,due to facing brilliant developing opportunity at the related frontier at home,investment casting is the first choice for producing the products above mentioned at a possible future,so taking opportunity for investment castings with high added value.However,restriction of some factors,such as existing system,mechanism,management ability from the enterprise and technological bottleneck,would take severe challege.关键词：Investment Casting;High Added Value Components;Turbine Blade;Thin-Walled Aluminum Alloy Parts;Tubocharge for Car Engine
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发布时间：2023-12-18 - 摘要：Application of five-axis machining center has changed the traditional way of wooden pattern machining,saved labor cost,reduced labor intensity,shortened the development cycle and improved the precision of patterns,and thus improved the casting quality.关键词：Five-Axis Machining Center;Vacuum Casting;Wooden Pattern
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发布时间：2023-12-18 - 摘要：Aimed at crack accident of high Cr cast iron roller from a company,through analyzing the appearance,the fracture microstructure with the help of SEM（scanning electron microscope）,the hardness measurememt,the energy spectrum and the microstructure,origination of the crack in high Cr cast iron was approached.Macro-fracture is characterized by crack source area,propagation area and instantaneous fault area.SEM analysis shows that the crack of the roller is characterized by fatigue fracture with transgranular crack.The energy spectrum reveal that the carbide is composed of M7C3、M23C6、Mo2C and so on,and spherical black phase consists of graphite and some oxide inclusion.The eutectic carbide with net-like shape is distributed along the grain boundary,which might be responsible for the crack.关键词：High Cr Casting Iron Roller;Fatigue Fracture;SEM;Energy Spectrum;Eutectic Carbide
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发布时间：2023-12-18 - 摘要：10%SiCP with 10μm and 150μm in size reinforced A356metalmatrix composites were fabricated by stirring casting and then direct squeeze casting process under 75MPa.Effects of particle size on the microstructures and mechanical properties of the castings were investigated.The results show that compared to 10μm SiCp/A356composites,squeezing casting 150μm SiCp/A356composites exhibit less internal defects and higher density as well as lower tendency of particle cluster.The as-cast tensile strength,hardness and elongation of 10μm SiCp/A356composites are superior to those of 150μm SiCp/A356composites.After T6heat treatment,the mechanical properties of both 150μm SiCp/A356and 10μm SiCp/A356composites are increased greatly,however,tensile strength and hardness of 150μm SiCp/A356composites are higher than those of 10μm SiCp/A356composites.关键词：Metal Matrix Composites;Squeeze Casting;Microstructures
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发布时间：2023-12-18 - 摘要：Influences of different pulse voltage,pouring temperature and mold temperature on the solidified structure of 7075aluminum alloy under pulsed magnetic field were investigated,and the related mechanism was also described.The results show that solidification structure of 7075alloy can be refined obviously under the pulsed magnetic field.The primary phase of the 7075alloy is transformed from developed dendrites into rossette-like or spherical crystals.With pulse voltage increasing from 0to 210V,pouring temperature decreasing from 730 ℃to 640 ℃ or mold temperature decreasing from 600 ℃to room temperature,the average grain size of the alloy is decreased.When pulse voltage is 210V,the average grain size of the alloy reaches 252μm.With pouring temperature or mold temperature increases,primary grain in the alloy becomes spherical structure increasingly.The grain refinement mechanism of the alloy is characterized by electromagnetic stirring and electromagnetic oscillation under the pulsed magnetic field.关键词：Pulsed Magnetic Field;7075Alloy;Solidification Structure
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发布时间：2023-12-18 - 摘要：Based on the process of coupling cellular automaton with finite element,the mathematical model of nucleation and grain growth of 7085aluminum alloy was established.Growth kinetics parameters of7085aluminum alloy were given by using extended KGT model calculation.The simulated and experimental results show that the grain size is obviously refined and the morphology of grain is changed into equiaxed grain from dendrite.Meanwhile,the average grain size is decreased from 535μm without ultrasonic to 241μm（170W）and 197μm（240W）.The increase of nucleation rate plays a main role in grain refinement,and the contribution of grain nucleation growth is the minor effect.关键词：7085Aluminum Alloy;Ultrasonic;Grain Growth;CAF;Microstructure Simulation
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发布时间：2023-12-18 - 摘要：A detection algorithm was presented for weak and dim target on magnesium melt based on the BP neural network,which aimed at image identification of the initial bubble under complex background.At first,the function approximation characteristic of BP neural network was used to estimate the background of original image.Then,the reconstructed images were obtained by subtracting the background from original image.And then,the frame difference was used for the reconstructed images.At last,the weak and dim target was detected by using self-adaptive threshold and morphological opening operation.The results show that BP neural network algorithm is effective for the initial bubble identification,and it can provide a new method for detection of hydrogen content in magnesium melt based on image processing technology.关键词：Magnesium Melt;Initial Bubble;BP Neural Network;Background Estimation;Self-Adaptive Threshold
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发布时间：2023-12-18 - 摘要：Through using vacuum induction melting with the help of the protection of Ar atmosphere,effects of SiC content on the microstructure refinement and morphology transformation of AZ91D magnesium alloy were investigated.The results reveal that the addition of SiC particle can generate Mg2Si phase with the melting temperature in range of 700℃ 720℃.With the increase of SiC content,the volume fraction of Mg2Si phase is increased and its morphology is changed from the linear-shaped Chinese script to coarse fish bone and polygonal structure.Meanwhile,theβphase becomes smaller and dispersed.Due to the existence of residual SiC particle and the Al4C3generated as nuclei with 0.2%SiC addition,heterogeneous nucleation is promoted,where grain size of the alloy is refined from 480μm to 124μm,obtaining desirable refining effects.关键词：SiC Content;AZ91D Magnesium Alloys;Mg2Si;Grain Refinement
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发布时间：2023-12-18 - 摘要：Effects of different cooling intensity,such as graphite mold,iron mold and iron mold with water cooling,on the as-cast microstructure of Cu-15Ni-15Mn alloy were investigated,and the relationship of dendrite morphology and grain size with the hardness of the alloy was described.The results show that the size of dendrite and characteristics of Cu-15Ni-15Mn alloy are closely relative with cooling intensity.With the increase of the cooling intensity,the size of primary dendrite,the secondary dendrites and the space between dendrites are decreased.The size of primary dendrite of alloy cooled in iron mold and in iron mold with water cooling reaches 20.82μm and 8.09μm,respectively,reduced by 43.7%and by78.1% respectively,comparing with that of the alloy cooled in graphite mold.It is beneficial to strengthening the hardness of alloy by increasing the cooling intensity.The hardness（HV）of alloy cooled in iron mold and in iron mold with water cooling reaches 96and103,respectively,enhanced by10%and by 19.8%,respectively,comparing with that of one in graphite mold.关键词：Cu-15Ni-15Mn Alloy;As-cast;Cooling Intensity;Structure;Hardness
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发布时间：2023-12-18 - 摘要：<正>宣德炉（见下页）[1]明宣德三年（1428年）始铸高10.6 cm,质量1.78 kg黄铜台北故宫博物院藏明宣德三年,明宣宗谕工部尚书吕震,用暹罗国所贡"风磨铜"（后有研究者称属天然黄铜）于工部所设铸冶局铸鼎彝以供郊坛宗庙内廷之用。工部监铸官为吴邦佐,在铸冶局使张护、许百禄率领下,用工匠64人以失蜡法铸器3765件,所铸之器后统称为宣德炉或宣炉。这件台北故宫博物院藏宣德炉通体鎏金并杂以黑色和朱红色斑,炫丽华美,原属清宫养心殿御用[1]。
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发布时间：2023-12-18 - 摘要：<正>20131001一种缸套离心铸造模具,CN102806331A,2012.12.05,苏州市东立机械有限公司.本发明公开了一种缸套离心铸造模具,包括模具外壳、挡板,所述模具外壳内部为内腔;所述内腔内径依次递减,呈台阶状;所述内腔的成型形状与成品缸套的外形相同;所述挡板设置在模具外壳一端;本发明方案通过在模具内腔设置依次递减台阶,使生产出毛坯外圆面呈台阶状,同成品缸套的外圆面形状基本一致,这样,毛坯的加工余量和质量大为降低,大大的节省了成本和劳动力,提高了生产效率。
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发布时间：2023-12-18 - 摘要：<正>7月伊始,2014年第十二届中国国际铸造博览会的招展工作全面启动,基于往届展会令人交口称赞的展出效果,本届展会从一开始招展,就得到新老客户的积极回应,截止2013年9月22日,已经有500余家知名企业和15个展团报名参展,超过75%的展位已经售出,其中装备馆（E4）、材料馆（E3）的展位已所剩无几,屡屡出现多家企业争一个展位的情况,比往届提前3个月掀起展位抢定热潮。
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发布时间：2023-12-18
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