In this paper, we study the interconnect buffer and wiresizing optimization problem under a distributed RLC model to optimize not just area and delay, but also crosstalk for RLC circuit with non-monotone signal respon...In this paper, we study the interconnect buffer and wiresizing optimization problem under a distributed RLC model to optimize not just area and delay, but also crosstalk for RLC circuit with non-monotone signal response. We present a new multiobjective genetic algorithm（MOGA） which uses a single objective sorting（SOS） method for constructing the non-dominated set to solve this multi-objective interconnect optimization problem. The MOGA/SOS optimal algorithm provides a smooth trade-off among signal delay, wave form, and routing area. Furthermore, we use a new method to calculate the lower bound of crosstalk. Extensive experimental results show that our algorithm is scalable with problem size. Furthermore, compared to the solution based on an Elmore delay model, our solution reduces the total routing area by up to 30%, the delay to the critical sinks by up to 25%, while further improving crosstalk up to 25.73% on average.展开更多
The ultrafine copper wire with a diameter of 18μm is prepared via cold drawing process from the single crystal downcast billet(Φ8 mm),taking a drawing strain to 12.19.In this paper,in-depth investigation of the micr...The ultrafine copper wire with a diameter of 18μm is prepared via cold drawing process from the single crystal downcast billet(Φ8 mm),taking a drawing strain to 12.19.In this paper,in-depth investigation of the microstructure feature,texture evolution,mechanical properties,and electrical conductivity of ultrafine wires ranging fromΦ361μm toΦ18μm is performed.Specially,the microstructure feature and texture type covering the whole longitudinal section of ultrafine wires are elaborately characterized.The results show that the average lamella thickness decreases from 1.63μm to 102 nm during the drawing process.Whereas,inhomogeneous texture evolution across different wire sections was observed.The main texture types of copper wires are comprised of<111>,<001>and<112>orientations.Specifically,the peripheral region is primarily dominated by<111>and<112>,while the central region is dominated by<001>and<111>.As the drawing strain increases,the volume fraction of hard orientation<111>with low Schmid factor increases,where notably higher fraction of<111>is resulted from the consumption of<112>and<001>for the wire ofΦ18μm.For drawn copper wire of 18μm,superior properties are obtained with a tensile strength of 729.8 MPa and an electrical conductivity of 86.9%IACS.Furthermore,it is found that grain strengthening,dislocation strengthening,and texture strengthening are three primary strengthening mechanisms of drawn copper wire,while the dislocation density is the main factor on the reducing of conductivity.展开更多
CHINESE Cloisonneis the centuries-old handicraft of creating designs on copper bodies with colored-enamel placed within divisions made of copper wires,which are bent to follow the outline of decorative patterns.This f...CHINESE Cloisonneis the centuries-old handicraft of creating designs on copper bodies with colored-enamel placed within divisions made of copper wires,which are bent to follow the outline of decorative patterns.This form of art originated in the Arab world and was introduced to China during the late Yuan Dynasty(1271-1368),and since then it has become a favorite of the country’s emperors.展开更多
Combining the advantages of high efficiency,low-pressure drop,and large throughput,the pore arrayenhanced tube-in-tube microchannel(PA-TMC) is a promising microreactor for industrial applications.However,most of the m...Combining the advantages of high efficiency,low-pressure drop,and large throughput,the pore arrayenhanced tube-in-tube microchannel(PA-TMC) is a promising microreactor for industrial applications.However,most of the mass transfer takes place in the upstream pore region,while the contribution of the downstream annulus is limited.In this work,helical wires were introduced into the annulus by adhering to the outer surface of the inner tube.Mixing behavior and mass transfer of liquid-liquid twophase flow in PA-TMC with different helical wires have been systematically studied by a combination of experiments and volume of fluid(VOF) method.The introduction of helical wires improves the overall volumetric mass transfer coefficient KLa by up to 133% and the mass transfer efficiency E by up to 117%.The simulation results show that the helical wire brings extra phase mixing regions and increases the specific interface area,while accelerating the fluid flow and expanding the area of enhanced turbulent dissipation rate.Influences of helical wires in various configurations are compared by the comprehensive index I concerning the pressure drop and mass transfer performance simultaneously and a new correlation between KLa and specific energy consumption φ is proposed.This research deepens the understanding of the mixing behavior and mass transfer in the PA-TMCs and provides practical experience for the process intensification of microchannel reactors.展开更多
We theoretically investigate the electronic structure of cylindrical magnetic topological insulator quantum wires in MnBi_(2)Te_(4).Our study reveals the emergence of topological surface states in the ferromagnetic ph...We theoretically investigate the electronic structure of cylindrical magnetic topological insulator quantum wires in MnBi_(2)Te_(4).Our study reveals the emergence of topological surface states in the ferromagnetic phase,characterized by spin-polarized subbands resulting from intrinsic magnetization.In the antiferromagnetic phase,we identify the coexistence of three distinct types of topological states,encompassing both surface states and central states.展开更多
To improve the heat transfer efficiency of the coolant in lead-based fast reactors,this study optimized the configuration and rotational direction of the spacer wires in fuel assemblies to design a new-pattern fuel as...To improve the heat transfer efficiency of the coolant in lead-based fast reactors,this study optimized the configuration and rotational direction of the spacer wires in fuel assemblies to design a new-pattern fuel assembly.This study conducted detailed comparisons between traditional and new pattern fuel assembly rod bundles utilizing the open-source computational fluid dynamics platform,OpenFOAM.The results indicated that the new design may significantly reduce the pressure drop along the rod bundle,which is beneficial for lowering the pressure drop.Furthermore,this new design improved coolant mixing in the subchannels,which facilitated a more uniform temperature distribution and lower thermal gradients at the assembly outlet.These factors collectively reduced the thermal fatigue and creep in nearby internal components.Overall,the newpattern fuel assembly proposed in this study may have better heat transfer performance,thereby enhancing the Integrated Thermal-Hydraulic Factor by 48.2% compared to the traditional pattern.展开更多
The Zn0.6Cu wires are fabricated into stents for the potential biodegradable application of nasal wound healing.The degradation behavior of Zn0.6Cu stents in 0.9 wt%NaCl at 36.5℃ is evaluated.It shows that the untrea...The Zn0.6Cu wires are fabricated into stents for the potential biodegradable application of nasal wound healing.The degradation behavior of Zn0.6Cu stents in 0.9 wt%NaCl at 36.5℃ is evaluated.It shows that the untreated Zn0.6Cu stent experiences severe crevice corrosion with acceleration and autocatalytic effects within the micro-cracks and ruptures at 4.67±1.15 d,with the average corrosion rate of 0.28 mm y^(-1).Fortunately,the anodic polarization(AP)+hydrothermal(H)conversion coating,consisting of ZnCO_(3),Zn(OH)_(2) and ZnO,could inhibit the crevice corrosion significantly by reducing the cathode/anode ratio,extending the rupture time up to 16.50±2.95 d,with the average corrosion rate of 0.14 mm y^(-1).This research indicates that the biodegradable Zn-based stent has some potential applications in nasal wound recovery area.展开更多
The high cost of using the niobium(Nb)barrier for manufacturing magnesium diboride(MgB2)mono-and multi-filamentary wires for large-scale applications has become one of the barriers to replacing current commercial niob...The high cost of using the niobium(Nb)barrier for manufacturing magnesium diboride(MgB2)mono-and multi-filamentary wires for large-scale applications has become one of the barriers to replacing current commercial niobium-titanium superconductors.The potential of replacing the Nb barrier with a low-cost iron(Fe)barrier for multifilament MgB2 superconducting wires is investigated in this manuscript.Therefore,MgB2 wires with Fe barrier sintered with different temperatures are studied(from 650°C to 900°C for 1 h)to investigate the non-superconducting reaction phase of Fe-B.Their superconducting performance including engineering critical current density(Je)and n-value are tested at 4.2 K in various external magnetic fields.The best sample sintered at 650°C for 1 h has achieved a Je value of 3.64×10^(4) A cm^(−2) and an n-value of 61 in 2 T magnetic field due to the reduced formation of Fe2B,better grain connectivity and homogenous microstructure.For microstructural analysis,the focused ion beam(FIB)is utilised for the first time to acquire three-dimensional microstructures and elemental mappings of the interface between the Fe barrier and MgB2 core of different wires.The results have shown that if the sintering temperature can be controlled properly,the Je and n-value of the wire are still acceptable for magnet applications.The formation of Fe2B is identified along the edge of MgB2,as the temperature increases,the content of Fe2B also increases which causes the degradation in the performance of wires.展开更多
Building on a new model proposed recently for calculating constant electro-magnetic field values, the present article explores the electro-magnetic field configuration generated by parallel electrical wires. This impo...Building on a new model proposed recently for calculating constant electro-magnetic field values, the present article explores the electro-magnetic field configuration generated by parallel electrical wires. This imposes a reevaluation of the drawing procedure for constructing field curves with a constant field values around multiple parallel electrical conducting wires. To achieve this, we employ methods akin to those used for creating contours on topographical maps, ensuring a consistent numerical field value along the entire length of the field curves. Subsequent calculations will be conducted for scenarios where wires are not parallel.展开更多
This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with...This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with the new concept of magnetic equipotential surface to magnetic field curves around crossing wires. Cases of single, double, and triple wires are described. Subsequent article will be conducted for more general scenarios where wires are neither infinite nor parallel.展开更多
In order to obtain the Al wires with good mechanical properties and high electrical conductivities, conductive wires of Al-0.16 Zr, Al-0.16 Sc, Al-0.12Sc-0.04Zr（mass fraction, %） and pure Al（99.996%） were produced...In order to obtain the Al wires with good mechanical properties and high electrical conductivities, conductive wires of Al-0.16 Zr, Al-0.16 Sc, Al-0.12Sc-0.04Zr（mass fraction, %） and pure Al（99.996%） were produced with the diameter of 9.5 mm by continuous rheo-extrusion technology, and the extruded materials were heat treated and analyzed. The results show that the separate additions of 0.16% Sc and 0.16% Zr to pure Al improve the ultimate tensile strength but reduce the electrical conductivity, and the similar trend is found in the Al-0.12Sc-0.04 Zr alloy. After the subsequent heat treatment, the wire with the optimum comprehensive properties is Al-0.12Sc-0.04 Zr alloy, of which the ultimate tensile strength and electrical conductivity reach 160 MPa and 64.03%（IACS）, respectively.展开更多
The texture evolution of cold drawing copper wires produced by continuous casting was measured by X-ray diffractometry and electron back-scatter diffractometry,and was simulated using Taylor model.The results show tha...The texture evolution of cold drawing copper wires produced by continuous casting was measured by X-ray diffractometry and electron back-scatter diffractometry,and was simulated using Taylor model.The results show that in the drawn poly-crystal copper wires produced by traditional continuous casting,111 and 100 duplex fiber texture forms,and with increasing strain,the intensities of 111 and 100 increase.In the drawn single-crystal copper wires produced by Ohno continuous casting,100 rotates to 111,and there is inhomogeneous distribution of fiber texture along radial direction of the wires,which is caused by the distribution of shear deformation.Compared with 100,111 fiber texture is more stable in the drawn copper wires.Comparison of the experimental results with the simulated results shows that the simulation by Taylor model can analyze the texture evolution of drawn copper wires.展开更多
The nanosystem has received considerable attention because of its peculiar pheno mena,which is different from macroscopy and microscopy. At present,the upsurge o f researching nanomaterials has shifted from nano parti...The nanosystem has received considerable attention because of its peculiar pheno mena,which is different from macroscopy and microscopy. At present,the upsurge o f researching nanomaterials has shifted from nano particles to one dimensional na nosystem,such as nanowires,nanotubes,and so on.Seen from literatures, the repor ts on carbon nanotubes wer e more,on nanowires were less,and on transition metallic salt nanowires were noth ing .In this paper,AgCl nanocrystalline wires were successfully synthesized by Rever s e Micelle soft Templates, which will open a new way for the synthesis and applic ation of one dimensional nanomaterials.展开更多
The heterostructure of InAs/In0.52Al0.48As/InP is unique in that InAs wires instead of dots self-assemble in molecular beam epitaxy. These InAs wires have some distinctive features in their growth and structure. This ...The heterostructure of InAs/In0.52Al0.48As/InP is unique in that InAs wires instead of dots self-assemble in molecular beam epitaxy. These InAs wires have some distinctive features in their growth and structure. This paper summarizes the investigations of the growth and structural properties of InAs wires that have been performed in our laboratory recently.展开更多
A new approach was proposed to construct a performance-driven rectilinear Steiner tree with simultaneous buffer insertion and wiresizing optimization (PDRST/BW) under a higher order resistance-inductance-capacitance (...A new approach was proposed to construct a performance-driven rectilinear Steiner tree with simultaneous buffer insertion and wiresizing optimization (PDRST/BW) under a higher order resistance-inductance-capacitance (RLC) delay model. This approach is based on the concept of sharing-buffer insertion and dynamic programming approach combined with a bottom-up rectilinear Steiner tree construction. The performances include the timing delay and the quality of signal waveform. The experimental results show that our proposed approach is scalable and obtains better performance than SP-tree and graph-RTBW approaches for the test signal nets.展开更多
Coaxially dielectric samples consisting of different packing ratios of glass-covered Fe73.5Si13.5B9Nb3Cu1 amorphous wires embedded in a paraffin wax matrix were fabricated, and the influence of short-wire packing rati...Coaxially dielectric samples consisting of different packing ratios of glass-covered Fe73.5Si13.5B9Nb3Cu1 amorphous wires embedded in a paraffin wax matrix were fabricated, and the influence of short-wire packing ratio (3%-9% in mass fraction) and thickness (1-7 mm) on the microwave absorption properties was systematically investigated in microwave frequency range of 2-18 GHz. X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and scalar network analyzer (SNA) were used for characterizing microstructure and evaluating microwave absorption properties. Experimental results show the significant frequency (6-18 GHz) dependence of the complex relative permeability and permittivity. The reflection loss (RL) with different thickness and short-wire packing ratio reveals that the composite sample containing 7% exhibits better microwave absorption behavior with its minimum value of RL reaching-34 dB in thickness of 3 mm at 14 GHz. Therefore, it is significantly useful to develop microwire-dielectric materials with much wider absorption band for microwave absorption applications.展开更多
The flux cored wires with different amounts of rare earth （RE） oxides additions for hardfacing （harden-face-welding） the workpieces of high chromium cast iron were studied in this work.The morphology of carbides i...The flux cored wires with different amounts of rare earth （RE） oxides additions for hardfacing （harden-face-welding） the workpieces of high chromium cast iron were studied in this work.The morphology of carbides in hardfacing metal was observed,and the type of the carbides was determined by optical microscopy,scanning electron microscopy （SEM）,energy dispersive spectrometer （EDS） and X-ray diffraction （XRD）.Based on the data of effect of RE on carbides morphology,the refined reason for carbide by RE oxide was discussed with the misfit theory.The results showed that,the microstructure of hardfacing metal was composed of martensite,residual austenite and M7C3 carbides.With the increasing amount of RE oxide additions,the volume fraction and roundness of the carbides were increased,however,the area and perimeter of carbides were decreased.It indicated that carbides in hardfacing metal could be refined and spheroidized by adding RE oxides in flux cored wires.展开更多
In this study, we present a 2-step deposition method via sputtering and electroplating that uses carbon nanotube(CNT) wires synthesized from a wet-spinning technique to produce high-performance CNT/Au/Cu composite wir...In this study, we present a 2-step deposition method via sputtering and electroplating that uses carbon nanotube(CNT) wires synthesized from a wet-spinning technique to produce high-performance CNT/Au/Cu composite wires. After the Au sputtering pre-treatment, the deposition of Cu on the CNT wires was found to be much more homogeneous due to improved wettability and reactivity of the wire surface. At different electrodeposition time, the mechanical strength of the CNT/Au/Cu composite wires could be as high as 0.74 GPa(~2 times stronger than metal wires) while their electrical conductivity could reach 4.65 × 10~5 S/cm(~80% of that for copper). More importantly, the CNT/Au/Cu composite wires with high CNT volume fraction are expected to be lightweight(up to 42% lower than Cu mass density), suggesting that our high-performance composite wires are a promising candidate to substitute conventional heavy metal wires in the future applications.展开更多
（Fes3Ga17）98Cr2 wires each with a diameter of 0.7 mm are prepared by hot swaging and warm drawing from the casting rods directly, because the ductility of Fes3Ga17alloy is improved by adding Cr element. The Wiedeman...（Fes3Ga17）98Cr2 wires each with a diameter of 0.7 mm are prepared by hot swaging and warm drawing from the casting rods directly, because the ductility of Fes3Ga17alloy is improved by adding Cr element. The Wiedemann twists and dependences on magnetostrictions of Fe83Ga17 and （Fe83Ga17）98Cr2 wires are investigated. The largest observed Wiedemann twists of 245 s.cm-1 and 182 s.cm-1 are detected in the annealed Fes3Ga17 and （Fe83Ga17）98Cr2 wires, respectively. The magnetostrictions of the annealed Fes3Ga17 and （Fes3Ga17）98Cr2 wires are 160 ppm and 107 ppm, respectively. The maximum of the Wiedemann twist increases with magnetostriction increasing. However the magnetostriction is just one important factor that affects the Wiedemann effect of alloy wire, and the relationship between magnetostriction and Wiedemann effect is a complex function rather than a simple function.展开更多
A stranded wires helical spring is formed of a multilayer and coaxial strand of several wires twisted together with the same direction of spiral. Compared with the conventional single wire spring, the stranded wires h...A stranded wires helical spring is formed of a multilayer and coaxial strand of several wires twisted together with the same direction of spiral. Compared with the conventional single wire spring, the stranded wires helical spring has the notable predominance in strength, damping and vibration reduction, which is usually used in aircraft engines, automatic weapons, etc. However, due to its complicated structure, the precise computation of its strength and rigidity need be a correct mathematical model, which then will be imported to finite element analysis software for solutions. Equations on solving geometric parameters, such as external diameters of strands and screw pitches of wires, are put forward in the paper. It also proposes a novel methodology on solving geometric parameters and establishing entity models of the stranded wires helical spring, which provides foundation of computing mechanical parameters by FEA. Then mathematical models on the centre line of the strand and the surface curve of each wire, after closing two ends in a spring, are proposed. Finally, geometric parameters are solved in a case study, and a 3D entity model of a spring with 3 layers and 16 wires is established, which has validated the accuracy of the proposed methodology and the 3D entity mathematical model. The method provides a new way to design stranded wire helical spring.展开更多
基金Supported by the National Natural Science Foundation of China (90307017)
文摘In this paper, we study the interconnect buffer and wiresizing optimization problem under a distributed RLC model to optimize not just area and delay, but also crosstalk for RLC circuit with non-monotone signal response. We present a new multiobjective genetic algorithm（MOGA） which uses a single objective sorting（SOS） method for constructing the non-dominated set to solve this multi-objective interconnect optimization problem. The MOGA/SOS optimal algorithm provides a smooth trade-off among signal delay, wave form, and routing area. Furthermore, we use a new method to calculate the lower bound of crosstalk. Extensive experimental results show that our algorithm is scalable with problem size. Furthermore, compared to the solution based on an Elmore delay model, our solution reduces the total routing area by up to 30%, the delay to the critical sinks by up to 25%, while further improving crosstalk up to 25.73% on average.
基金Project supported by“Unveiled the List of Commanders”Key Core Common Technology Projects of Ji’an,ChinaProject(LJKMZ20220591)supported by the Basic Scientific Research Project of the Education Department of Liaoning Province,ChinaProject(CSTB2023NSCQ-LZX0116)supported by the Natural Science Foundation Joint Fund for Innovation and Development Projects of Chongqing,China。
文摘The ultrafine copper wire with a diameter of 18μm is prepared via cold drawing process from the single crystal downcast billet(Φ8 mm),taking a drawing strain to 12.19.In this paper,in-depth investigation of the microstructure feature,texture evolution,mechanical properties,and electrical conductivity of ultrafine wires ranging fromΦ361μm toΦ18μm is performed.Specially,the microstructure feature and texture type covering the whole longitudinal section of ultrafine wires are elaborately characterized.The results show that the average lamella thickness decreases from 1.63μm to 102 nm during the drawing process.Whereas,inhomogeneous texture evolution across different wire sections was observed.The main texture types of copper wires are comprised of<111>,<001>and<112>orientations.Specifically,the peripheral region is primarily dominated by<111>and<112>,while the central region is dominated by<001>and<111>.As the drawing strain increases,the volume fraction of hard orientation<111>with low Schmid factor increases,where notably higher fraction of<111>is resulted from the consumption of<112>and<001>for the wire ofΦ18μm.For drawn copper wire of 18μm,superior properties are obtained with a tensile strength of 729.8 MPa and an electrical conductivity of 86.9%IACS.Furthermore,it is found that grain strengthening,dislocation strengthening,and texture strengthening are three primary strengthening mechanisms of drawn copper wire,while the dislocation density is the main factor on the reducing of conductivity.
文摘CHINESE Cloisonneis the centuries-old handicraft of creating designs on copper bodies with colored-enamel placed within divisions made of copper wires,which are bent to follow the outline of decorative patterns.This form of art originated in the Arab world and was introduced to China during the late Yuan Dynasty(1271-1368),and since then it has become a favorite of the country’s emperors.
基金the National Natural Science Foundation of China(22208320)the Science and Technology Program of Henan Province(212102210044)The Henan Association for Science and Technology Youth Talent Support Program(2022HYTP026).
文摘Combining the advantages of high efficiency,low-pressure drop,and large throughput,the pore arrayenhanced tube-in-tube microchannel(PA-TMC) is a promising microreactor for industrial applications.However,most of the mass transfer takes place in the upstream pore region,while the contribution of the downstream annulus is limited.In this work,helical wires were introduced into the annulus by adhering to the outer surface of the inner tube.Mixing behavior and mass transfer of liquid-liquid twophase flow in PA-TMC with different helical wires have been systematically studied by a combination of experiments and volume of fluid(VOF) method.The introduction of helical wires improves the overall volumetric mass transfer coefficient KLa by up to 133% and the mass transfer efficiency E by up to 117%.The simulation results show that the helical wire brings extra phase mixing regions and increases the specific interface area,while accelerating the fluid flow and expanding the area of enhanced turbulent dissipation rate.Influences of helical wires in various configurations are compared by the comprehensive index I concerning the pressure drop and mass transfer performance simultaneously and a new correlation between KLa and specific energy consumption φ is proposed.This research deepens the understanding of the mixing behavior and mass transfer in the PA-TMCs and provides practical experience for the process intensification of microchannel reactors.
基金Project sponsored by the Natural Science Foundation of Chongqing,China(Grant No.CSTB2024NSCQMSX0736)the Special Project of Chongqing Technology Innovation and Application Development(Major Project)(Grant No.CSTB2024TIAD-STX0035)the Research Foundation of Institute for Advanced Sciences of CQUPT(Grant No.E011A2022328)。
文摘We theoretically investigate the electronic structure of cylindrical magnetic topological insulator quantum wires in MnBi_(2)Te_(4).Our study reveals the emergence of topological surface states in the ferromagnetic phase,characterized by spin-polarized subbands resulting from intrinsic magnetization.In the antiferromagnetic phase,we identify the coexistence of three distinct types of topological states,encompassing both surface states and central states.
基金supported partly by the Ministry of Science and Technology of the People’s Republic of China(No.2020YFB1902100)the China Postdoctoral Science Foundation(No.2023M731458)+3 种基金the Science and Technology Program of Gansu ProvinceChina(No.23JRRA1099)the Postdoctoral Fellowship Program of CPSF(No.GZB20230278)financially supported by the Shanghai Municipal Commission of Economy and Informatization(No.GYQJ-2018-2-02)。
文摘To improve the heat transfer efficiency of the coolant in lead-based fast reactors,this study optimized the configuration and rotational direction of the spacer wires in fuel assemblies to design a new-pattern fuel assembly.This study conducted detailed comparisons between traditional and new pattern fuel assembly rod bundles utilizing the open-source computational fluid dynamics platform,OpenFOAM.The results indicated that the new design may significantly reduce the pressure drop along the rod bundle,which is beneficial for lowering the pressure drop.Furthermore,this new design improved coolant mixing in the subchannels,which facilitated a more uniform temperature distribution and lower thermal gradients at the assembly outlet.These factors collectively reduced the thermal fatigue and creep in nearby internal components.Overall,the newpattern fuel assembly proposed in this study may have better heat transfer performance,thereby enhancing the Integrated Thermal-Hydraulic Factor by 48.2% compared to the traditional pattern.
基金supported by the National Natural Science Foundation of China(No.51975592).
文摘The Zn0.6Cu wires are fabricated into stents for the potential biodegradable application of nasal wound healing.The degradation behavior of Zn0.6Cu stents in 0.9 wt%NaCl at 36.5℃ is evaluated.It shows that the untreated Zn0.6Cu stent experiences severe crevice corrosion with acceleration and autocatalytic effects within the micro-cracks and ruptures at 4.67±1.15 d,with the average corrosion rate of 0.28 mm y^(-1).Fortunately,the anodic polarization(AP)+hydrothermal(H)conversion coating,consisting of ZnCO_(3),Zn(OH)_(2) and ZnO,could inhibit the crevice corrosion significantly by reducing the cathode/anode ratio,extending the rupture time up to 16.50±2.95 d,with the average corrosion rate of 0.14 mm y^(-1).This research indicates that the biodegradable Zn-based stent has some potential applications in nasal wound recovery area.
基金support from the Australian Research Council(ARC)Linkage Project(LP200200689).
文摘The high cost of using the niobium(Nb)barrier for manufacturing magnesium diboride(MgB2)mono-and multi-filamentary wires for large-scale applications has become one of the barriers to replacing current commercial niobium-titanium superconductors.The potential of replacing the Nb barrier with a low-cost iron(Fe)barrier for multifilament MgB2 superconducting wires is investigated in this manuscript.Therefore,MgB2 wires with Fe barrier sintered with different temperatures are studied(from 650°C to 900°C for 1 h)to investigate the non-superconducting reaction phase of Fe-B.Their superconducting performance including engineering critical current density(Je)and n-value are tested at 4.2 K in various external magnetic fields.The best sample sintered at 650°C for 1 h has achieved a Je value of 3.64×10^(4) A cm^(−2) and an n-value of 61 in 2 T magnetic field due to the reduced formation of Fe2B,better grain connectivity and homogenous microstructure.For microstructural analysis,the focused ion beam(FIB)is utilised for the first time to acquire three-dimensional microstructures and elemental mappings of the interface between the Fe barrier and MgB2 core of different wires.The results have shown that if the sintering temperature can be controlled properly,the Je and n-value of the wire are still acceptable for magnet applications.The formation of Fe2B is identified along the edge of MgB2,as the temperature increases,the content of Fe2B also increases which causes the degradation in the performance of wires.
文摘Building on a new model proposed recently for calculating constant electro-magnetic field values, the present article explores the electro-magnetic field configuration generated by parallel electrical wires. This imposes a reevaluation of the drawing procedure for constructing field curves with a constant field values around multiple parallel electrical conducting wires. To achieve this, we employ methods akin to those used for creating contours on topographical maps, ensuring a consistent numerical field value along the entire length of the field curves. Subsequent calculations will be conducted for scenarios where wires are not parallel.
文摘This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with the new concept of magnetic equipotential surface to magnetic field curves around crossing wires. Cases of single, double, and triple wires are described. Subsequent article will be conducted for more general scenarios where wires are neither infinite nor parallel.
基金Project(51222405)supported by the National Natural Science Foundation for Outstanding Young Scholars of ChinaProject(51034002)supported by the National Natural Science Foundation of ChinaProject(120502001)supported by the Fundamental Research Funds for the Central Universities of China
文摘In order to obtain the Al wires with good mechanical properties and high electrical conductivities, conductive wires of Al-0.16 Zr, Al-0.16 Sc, Al-0.12Sc-0.04Zr（mass fraction, %） and pure Al（99.996%） were produced with the diameter of 9.5 mm by continuous rheo-extrusion technology, and the extruded materials were heat treated and analyzed. The results show that the separate additions of 0.16% Sc and 0.16% Zr to pure Al improve the ultimate tensile strength but reduce the electrical conductivity, and the similar trend is found in the Al-0.12Sc-0.04 Zr alloy. After the subsequent heat treatment, the wire with the optimum comprehensive properties is Al-0.12Sc-0.04 Zr alloy, of which the ultimate tensile strength and electrical conductivity reach 160 MPa and 64.03%（IACS）, respectively.
基金Projects(50771076,50901055)supported by the National Natural Science Foundation of ChinaProject(07JK274)supported by the Education Department Foundation of Shaanxi Province,China
文摘The texture evolution of cold drawing copper wires produced by continuous casting was measured by X-ray diffractometry and electron back-scatter diffractometry,and was simulated using Taylor model.The results show that in the drawn poly-crystal copper wires produced by traditional continuous casting,111 and 100 duplex fiber texture forms,and with increasing strain,the intensities of 111 and 100 increase.In the drawn single-crystal copper wires produced by Ohno continuous casting,100 rotates to 111,and there is inhomogeneous distribution of fiber texture along radial direction of the wires,which is caused by the distribution of shear deformation.Compared with 100,111 fiber texture is more stable in the drawn copper wires.Comparison of the experimental results with the simulated results shows that the simulation by Taylor model can analyze the texture evolution of drawn copper wires.
文摘The nanosystem has received considerable attention because of its peculiar pheno mena,which is different from macroscopy and microscopy. At present,the upsurge o f researching nanomaterials has shifted from nano particles to one dimensional na nosystem,such as nanowires,nanotubes,and so on.Seen from literatures, the repor ts on carbon nanotubes wer e more,on nanowires were less,and on transition metallic salt nanowires were noth ing .In this paper,AgCl nanocrystalline wires were successfully synthesized by Rever s e Micelle soft Templates, which will open a new way for the synthesis and applic ation of one dimensional nanomaterials.
文摘The heterostructure of InAs/In0.52Al0.48As/InP is unique in that InAs wires instead of dots self-assemble in molecular beam epitaxy. These InAs wires have some distinctive features in their growth and structure. This paper summarizes the investigations of the growth and structural properties of InAs wires that have been performed in our laboratory recently.
基金The National Natural Science Foundation of China (No. 90307017)
文摘A new approach was proposed to construct a performance-driven rectilinear Steiner tree with simultaneous buffer insertion and wiresizing optimization (PDRST/BW) under a higher order resistance-inductance-capacitance (RLC) delay model. This approach is based on the concept of sharing-buffer insertion and dynamic programming approach combined with a bottom-up rectilinear Steiner tree construction. The performances include the timing delay and the quality of signal waveform. The experimental results show that our proposed approach is scalable and obtains better performance than SP-tree and graph-RTBW approaches for the test signal nets.
基金Project(51371067)supported by the National Natural Science Foundation of China
文摘Coaxially dielectric samples consisting of different packing ratios of glass-covered Fe73.5Si13.5B9Nb3Cu1 amorphous wires embedded in a paraffin wax matrix were fabricated, and the influence of short-wire packing ratio (3%-9% in mass fraction) and thickness (1-7 mm) on the microwave absorption properties was systematically investigated in microwave frequency range of 2-18 GHz. X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and scalar network analyzer (SNA) were used for characterizing microstructure and evaluating microwave absorption properties. Experimental results show the significant frequency (6-18 GHz) dependence of the complex relative permeability and permittivity. The reflection loss (RL) with different thickness and short-wire packing ratio reveals that the composite sample containing 7% exhibits better microwave absorption behavior with its minimum value of RL reaching-34 dB in thickness of 3 mm at 14 GHz. Therefore, it is significantly useful to develop microwire-dielectric materials with much wider absorption band for microwave absorption applications.
基金Project supported by One Hundred Excellent Talents of Hebei Province of China and Key Project of Science and Technology of Hebei Province (09215106D)
文摘The flux cored wires with different amounts of rare earth （RE） oxides additions for hardfacing （harden-face-welding） the workpieces of high chromium cast iron were studied in this work.The morphology of carbides in hardfacing metal was observed,and the type of the carbides was determined by optical microscopy,scanning electron microscopy （SEM）,energy dispersive spectrometer （EDS） and X-ray diffraction （XRD）.Based on the data of effect of RE on carbides morphology,the refined reason for carbide by RE oxide was discussed with the misfit theory.The results showed that,the microstructure of hardfacing metal was composed of martensite,residual austenite and M7C3 carbides.With the increasing amount of RE oxide additions,the volume fraction and roundness of the carbides were increased,however,the area and perimeter of carbides were decreased.It indicated that carbides in hardfacing metal could be refined and spheroidized by adding RE oxides in flux cored wires.
基金supported financially by the Lloyd’s Register Foundation (No.R-265-000-553-597).
文摘In this study, we present a 2-step deposition method via sputtering and electroplating that uses carbon nanotube(CNT) wires synthesized from a wet-spinning technique to produce high-performance CNT/Au/Cu composite wires. After the Au sputtering pre-treatment, the deposition of Cu on the CNT wires was found to be much more homogeneous due to improved wettability and reactivity of the wire surface. At different electrodeposition time, the mechanical strength of the CNT/Au/Cu composite wires could be as high as 0.74 GPa(~2 times stronger than metal wires) while their electrical conductivity could reach 4.65 × 10~5 S/cm(~80% of that for copper). More importantly, the CNT/Au/Cu composite wires with high CNT volume fraction are expected to be lightweight(up to 42% lower than Cu mass density), suggesting that our high-performance composite wires are a promising candidate to substitute conventional heavy metal wires in the future applications.
基金Project supported by the State Key Development Program for Basic Research of China (Grant No. 2011CB606304)the National Natural Science Foundation for Postdoctoral Scientists of China (Grant No. 2011M500229)the Program for New Century Excellent Talents in University,China (Grant No. NCET-09-02120)
文摘（Fes3Ga17）98Cr2 wires each with a diameter of 0.7 mm are prepared by hot swaging and warm drawing from the casting rods directly, because the ductility of Fes3Ga17alloy is improved by adding Cr element. The Wiedemann twists and dependences on magnetostrictions of Fe83Ga17 and （Fe83Ga17）98Cr2 wires are investigated. The largest observed Wiedemann twists of 245 s.cm-1 and 182 s.cm-1 are detected in the annealed Fes3Ga17 and （Fe83Ga17）98Cr2 wires, respectively. The magnetostrictions of the annealed Fes3Ga17 and （Fes3Ga17）98Cr2 wires are 160 ppm and 107 ppm, respectively. The maximum of the Wiedemann twist increases with magnetostriction increasing. However the magnetostriction is just one important factor that affects the Wiedemann effect of alloy wire, and the relationship between magnetostriction and Wiedemann effect is a complex function rather than a simple function.
基金supported by National Natural Science Foundation for Distinguished Young Scholar of China (Grant No. 50925518)National Natural Science Foundation of China (Grant No. 50775226)+1 种基金Key Project of Ministry of Education of China(Grant No. 109129)Chongqing Municipal Key Scientific and Technological Project of China (Grant No. CSTC2009AC3049)
文摘A stranded wires helical spring is formed of a multilayer and coaxial strand of several wires twisted together with the same direction of spiral. Compared with the conventional single wire spring, the stranded wires helical spring has the notable predominance in strength, damping and vibration reduction, which is usually used in aircraft engines, automatic weapons, etc. However, due to its complicated structure, the precise computation of its strength and rigidity need be a correct mathematical model, which then will be imported to finite element analysis software for solutions. Equations on solving geometric parameters, such as external diameters of strands and screw pitches of wires, are put forward in the paper. It also proposes a novel methodology on solving geometric parameters and establishing entity models of the stranded wires helical spring, which provides foundation of computing mechanical parameters by FEA. Then mathematical models on the centre line of the strand and the surface curve of each wire, after closing two ends in a spring, are proposed. Finally, geometric parameters are solved in a case study, and a 3D entity model of a spring with 3 layers and 16 wires is established, which has validated the accuracy of the proposed methodology and the 3D entity mathematical model. The method provides a new way to design stranded wire helical spring.
