Dendrite formation and side reactions,which originate from uncontrolled zinc(Zn)nucleation and growth and high water activity,remain the two critical challenges that hinder the practical implementation of Zn anodes fo...Dendrite formation and side reactions,which originate from uncontrolled zinc(Zn)nucleation and growth and high water activity,remain the two critical challenges that hinder the practical implementation of Zn anodes for rechargeable aqueous batteries.In this work,we propose a cation and anion comodulation strategy to realize highly textured and durable Zn anodes.As a proof of concept,1-ethyl-1-methylpyrrolidinium bromide(MEPBr)is selected as a versatile additive to regulate Zn deposition.Specifically,MEP^(+)cations with preferential adsorption on tips/edges first promote uniform primary Zn nucleation on the substrate,followed by dynamic“edge shielding”of existing deposits to guide highly oriented Zn growth.Meanwhile,the incorporation of Br^(-)anions promotes the enrichment of Zn^(2+)at the electrode-electrolyte interface(EEI),thereby facilitating Zn deposition kinetics.In addition,both the preferentially adsorbed MEP^(+)cations and Br^(-)anions create a water-poor EEI while the two ionic species disrupt the original hydrogen bond network and reduce water within the solvation structure in the bulk electrolyte through ion-water interactions,thus dramatically reducing water-induced side reactions.As a result,the Zn//Zn symmetric battery with the MEPBr-modulated electrolyte exhibits a remarkable lifespan of over 4000 h at 2 m A cm^(-2)and 1 mA h cm^(-2).More excitingly,the newly designed electrolyte enables a Zn//NaV_(3)O_(8)·1.5H_(2)O full battery with a thin Zn anode(50μm)and a high mass-loading cathode(~10 mg cm^(-2))to operate normally for over 300 cycles with remarkable capacity retention,showcasing its great potential for practical applications.展开更多
The textured roll and polished roll were applied instead of the ground roll in a 20-high mill to conduct two-pass rolling of 316L stainless steel strip with thickness of 0.027 mm.After the two-pass rolling with the te...The textured roll and polished roll were applied instead of the ground roll in a 20-high mill to conduct two-pass rolling of 316L stainless steel strip with thickness of 0.027 mm.After the two-pass rolling with the textured roll and polished roll(TPR),the surface roughness of the strip is dramatically reduced,and the surface topographical anisotropy index is diminished to 30.9%of the initial strip.Comparing with the strip rolled using the ground roll in both passes(GGR),the elongation of TPR rolled strip is obviously improved,and the mechanical property anisotropy is greatly weakened.The anisotropy index of tensile strength and elongation are 42.58%and 52.59%of that of GGR rolled strip,which is mainly attributed to the significant decrease of the texture intensity of the strip by TPR process.The results indicate that TPR process can obtain the stainless steel ultra-thin strip with smooth and uniform surface topography and good mechanical properties.展开更多
Molecular dynamics(MD)simulation is employed to investigate the deformation behavior under various loading paths and strain rates of nanocrystalline magnesium(NC Mg)with[0001]texture.Atomic-scale structural evolution ...Molecular dynamics(MD)simulation is employed to investigate the deformation behavior under various loading paths and strain rates of nanocrystalline magnesium(NC Mg)with[0001]texture.Atomic-scale structural evolution of NC Mg was performed under uniaxial and biaxial loadings.In tension process,compression twins and basal slip dominate,while the compression process is dominated by tension twins.The activation mechanism of twinning is highly sensitive to the loading path and grain orientation.Meanwhile,the effect of strain rate on the structural evolution of NC Mg was investigated.It is found that the effect of strain rate on the plastic deformation of NC Mg is reflected through the plasticity delays and the way to release the stress.As the strain rate decreases,the plastic deformation mechanism gradually changes from intragranular to grain boundary.Some significant potential deformation mechanisms in the loading process were studied.It is observed that{1121}twins nucleated inside the grains,and the thickening process is completed by basal〈a〉slip of the twin boundary.The strain compatibility between twins is automatically optimized with loading.Moreover,the detwinning mechanism caused by the interaction between twins and basal stacking faults is clarified.展开更多
Magnesium alloys have many advantages as lightweight materials for engineering applications,especially in the fields of automotive and aerospace.They undergo extensive cutting or machining while making products out of...Magnesium alloys have many advantages as lightweight materials for engineering applications,especially in the fields of automotive and aerospace.They undergo extensive cutting or machining while making products out of them.Dry cutting,a sustainable machining method,causes more friction and adhesion at the tool-chip interface.One of the promising solutions to this problem is cutting tool surface texturing,which can reduce tool wear and friction in dry cutting and improve machining performance.This paper aims to investigate the impact of dimple textures(made on the flank face of cutting inserts)on tool wear and chip morphology in the dry machining of AZ31B magnesium alloy.The results show that the cutting speed was the most significant factor affecting tool flank wear,followed by feed rate and cutting depth.The tool wear mechanism was examined using scanning electron microscope(SEM)images and energy dispersive X-ray spectroscopy(EDS)analysis reports,which showed that at low cutting speed,the main wear mechanism was abrasion,while at high speed,it was adhesion.The chips are discontinuous at low cutting speeds,while continuous at high cutting speeds.The dimple textured flank face cutting tools facilitate the dry machining of AZ31B magnesium alloy and contribute to ecological benefits.展开更多
Cutting tools are known as the“productivity”of the manufacturing industry,which affects the production efficiency and quality of the workpiece,and has become the focus of research and attention in academia and indus...Cutting tools are known as the“productivity”of the manufacturing industry,which affects the production efficiency and quality of the workpiece,and has become the focus of research and attention in academia and industry.However,traditional cutting tools often suffer from adhesion or wear during the cutting process,which considerably reduces the cutting efficiency and service life of the tools,and makes it difficult to meet current production requirements.To solve the above problems,scholars have introduced bionics into the tool’s design,applying the microscopic structure of the biological surface to the tool surface to alleviate the tool’s failure.This paper mainly summarizes the research progress of bionic textured cutting tools.Firstly,categorize whether the bionic texture design is inspired by a single organism or multiple organisms.Secondly,it is discussed that the non-smooth surface of the biological surface has five characteristics:hydrophilic lubricity,wear resistance,drag reduction and hydrophobicity,anti-adhesion,and arrangement,and the non-smooth structure of these different characteristics are applied to the surface of the tool is designed with bionic texture.Furtherly,the cutting performance of bionic textured cutting tools is discussed.The anti-friction and wear-resisting mechanism of bionic textured cutting tools is analyzed.Finally,some pending problems and perspectives have been proposed to provide new inspirations for the design of bionic textured cutting tools.展开更多
In this work,texturing is proposed to improve the piezoelectric response of PSN-PMN-PT ceramics.The PSN-PMN-PT textured ceramic with a Lotgering factor F001 higher than 99%was synthesized by the liquid-phase-assisted ...In this work,texturing is proposed to improve the piezoelectric response of PSN-PMN-PT ceramics.The PSN-PMN-PT textured ceramic with a Lotgering factor F001 higher than 99%was synthesized by the liquid-phase-assisted template grain growth(TGG)method.The addition of CuO/B2 O3 sintering aids improves the BT templates induced grain orientation growth behavior significantly.In comparison with its random counterpart,the Cu/B-T textured ceramic exhibits a high Lotgering factor F001 of 99%and significantly enhanced dielectric and piezoelectric responses:ε_(r)~3100,tanδ~0.8%,d_(33)~1030 pC N^(-1),d_(33)·g_(33)~34.2×10^(-12) m^(2) N^(-1),d_(33)∗~1490 pm V^(-1)@5 kV cm^(-1),Smax~0.26%@20 kV cm^(-1) and H_(s)~8.5%.In the meantime,good temperature stability is observed in the Cu/B-T textured ceramic with a variation of d_(33)∗@20 kV cm^(-1) and annealed d_(33) lower than 9.68%and 18.1%over a wide temperature range of 25-140°C.This work shows that PSN-PMN-PT textured ceramic(Cu/B-T)has great potential for electrome-chanical device applications such as precision actuators,ultrasound transducers,and energy harvesters.展开更多
Along with the increasing demand on exterior wall cladding as a protective cover for the interior elements and an indicator for modernity and architectural innovation,comes the need to develop new cladding materials t...Along with the increasing demand on exterior wall cladding as a protective cover for the interior elements and an indicator for modernity and architectural innovation,comes the need to develop new cladding materials that can replace the old ones and overcome their setbacks.This paper discusses the possibility of replacing stone by textured concrete as a cladding material in order to overcome the main challenges faced stone cladding by comparing them together.The comparison was made based on the main requirements of the cladding materials namely:economic,environmental,social,functional and structural aspects.展开更多
<001>textured Pb(Ni_(1/3)Nb_(2/3))O_(3)-PbZrO_(3)-PbTiO_(3)(PNN-PZT)ceramics were prepared by templated grain growth(TGG)technique using 0.36PNN-x PZ-(0.64-x)PT(x=0.23,0.25 and 0.27)powder matrix.Optimum templat...<001>textured Pb(Ni_(1/3)Nb_(2/3))O_(3)-PbZrO_(3)-PbTiO_(3)(PNN-PZT)ceramics were prepared by templated grain growth(TGG)technique using 0.36PNN-x PZ-(0.64-x)PT(x=0.23,0.25 and 0.27)powder matrix.Optimum template content was derived to achieve the best electromechanical properties of textured ceramics.The piezoelectric coefficient d33=1165 pC/N,Curie temperature T_(C)=197℃,longitudinal mode electrome-chanical coupling factor k33=0.86 and a very large effective piezoelectric strain coefficient d_(33)^(*)=2041 pm/V were simultaneously achieved at the morphotropic phase boundary(MPB)composition(x=0.25)with 3 vol.%BaTiO_(3)(BT)templates.Domain structures of textured ceramics were analyzed in detail to reveal the origin of these high piezoelectric and electromechanical properties.展开更多
In this study,a machine vision method is proposed to characterize 3D roughness of the textured surface on cylinder liner processed by plateau honing.The least absolute value(L∞)regression robust algorithm and Levenbe...In this study,a machine vision method is proposed to characterize 3D roughness of the textured surface on cylinder liner processed by plateau honing.The least absolute value(L∞)regression robust algorithm and Levenberg-Marquardt(LM)algorithm are employed to reconstruct image reference plane.On this basis,a single-hidden layer feedforward neural network(SLFNN)based on the extreme learning machine(ELM)is employed to model the relationship between high frequency information and 3D roughness.The characteristic parameters of Abbott-Firestone curve and 3D roughness measured by a confocal microscope are used to construct ELM-SLFNN prediction model for 3D roughness.The results indicate that the proposed method can effectively characterize 3D roughness of the textured surface of cylinder liner.展开更多
Repeated unidirectional bending （RUB） was carried out to improve the texture of commercial AZ31B magnesium alloy sheets. All specimens were prepared in the rolling direction. The forming limit diagrams （FLDs） of A...Repeated unidirectional bending （RUB） was carried out to improve the texture of commercial AZ31B magnesium alloy sheets. All specimens were prepared in the rolling direction. The forming limit diagrams （FLDs） of AZ31B magnesium alloy sheet were determined experimentally by conducting stretch-forming tests at room temperature, 100, 200 and 300 ℃ Compared with the as-received sheet, the lowest limited strain of AZ31B magnesium alloy sheet with tilted texture in the FLD increased by 79% at room temperature and 104% at 100 ℃. The texture also affected the extension of the forming limit curves （FLC） in the FLD. However, the FLCs of two kinds of sheets almost overlapped at temperature above 200 ℃. It can be concluded that the reduction of （0002） texture intensity is effective to the improvement of formability not only at room temperature but also at low-and-medium temperature. The effect of texture on FLDs becomes weak with increasing temperature.展开更多
Short carbon fiber felts with an initial porosity of 89.5% were deposited by isobaric, isothermal chemical vapor infiltration using natural gas as carbon source. The bulk density of the deposited carbon/carbon （C/C）...Short carbon fiber felts with an initial porosity of 89.5% were deposited by isobaric, isothermal chemical vapor infiltration using natural gas as carbon source. The bulk density of the deposited carbon/carbon （C/C） composites was 1.89 g/cm3 after depositing for 150 h. The microstructure and mechanical properties of the C/C composites were studied by polarized light microscopy, X-ray diffraction, scanning electron microscopy and three-point bending test. The results reveal that high textured pyrolytic carbon is deposited as the matrix of the composites, whose crystalline thickness and graphitization degree highly increase after heat treatment. A distinct decrease of the flexural strength and modulus accompanied by the increase of the toughness of the C/C composites is found to be correlated with the structural changes in the composites during the heat treatment process.展开更多
Detailed behaviors of nanoscale textured surfaces during the reciprocating sliding contacts are still unknown although they are widely used in mechanical components to improve tribological characteristics.The current ...Detailed behaviors of nanoscale textured surfaces during the reciprocating sliding contacts are still unknown although they are widely used in mechanical components to improve tribological characteristics.The current research of sliding contacts of textured surfaces mainly focuses on the experimental studies,while the cost is too high.Molecular dynamics(MD)simulation is widely used in the studies of nanoscale single-pass sliding contacts,but the CPU cost of MD simulation is also too high to simulate the reciprocating sliding contacts.In this paper,employing multiscale method which couples molecular dynamics simulation and finite element method,two dimensional nanoscale reciprocating sliding contacts of textured surfaces are investigated.Four textured surfaces with different texture shapes are designed,and a rigid cylindrical tip is used to slide on these textured surfaces.For different textured surfaces,average potential energies and average friction forces of the corresponding sliding processes are analyzed.The analyzing results show that"running-in"stages are different for each texture,and steady friction processes are discovered for textured surfaces II,III and IV.Texture shape and sliding direction play important roles in reciprocating sliding contacts,which influence average friction forces greatly.This research can help to design textured surfaces to improve tribological behaviors in nanoscale reciprocating sliding contacts.展开更多
Textured BaTiO_(3)(BT)-based lead-free ceramics have gained significant attention due to their high piezoelectric coefficient(d)and very large field induced strain(S).However,costly nano-size raw materials,excessively...Textured BaTiO_(3)(BT)-based lead-free ceramics have gained significant attention due to their high piezoelectric coefficient(d)and very large field induced strain(S).However,costly nano-size raw materials,excessively high sintering temperature and low Curie temperature(T_(c))hinder their device applications.In this work,highly[001]_(c)-oriented(Ba_(0.95)Ca_(0.05))(Zr_(0.04)Ti_(0.96))O_(3) ceramics with x mol%CuO(x=0.25,0.5,1.0,2.5)denoted as BCZT-x were synthesized by templated grain growth using micro-sized raw powders.The introduction of CuO sintering agent lowered the sintering temperature by 125℃ to 1450℃,and the BCZT-1.0 achieved a high texture degree of∼99%.In addition,the CuO-based liquid phases eliminated boundaries between BT templates and BCZT matrix powders.Such liquid-phase sintering reduced sintering stresses,decreased the average grain size of BCZT-1.0 from 16μm down to 13μm,and increased the dielectric dispersion coefficientγto 1.63.The almost smoothed out T_(O-T) anomaly in the temperature dependence of dielectric permittivity and comparably high T_(c)(>102℃)lead to better temperature stability.The narrower grain orientation distribution with full width at half maximum(FWHM)of∼5.9°and smaller domains with the size of 0.1–0.5μm in width and 3–8μm in length were obtained,a high field induced maximum strain S_(max) of 0.38%and low H_(s) of 5.2%have been achieved in BCZT-1.0 textured ceramics together with a high and homogeneous piezoelectric stress coefficient d_(33)∼780 pC/N and very large d_(33)∗∼2950 pm/V.展开更多
Nanoscale sliding contacts of smooth surfaces or between a single asperity and a smooth surface have been widely investigated by molecular dynamics simulations, while there are few studies on the sliding contacts betw...Nanoscale sliding contacts of smooth surfaces or between a single asperity and a smooth surface have been widely investigated by molecular dynamics simulations, while there are few studies on the sliding contacts between two rough surfaces. Actually, the friction of two rough surfaces considering interactions between more asperities should be more realistic. By using multiscale method, friction characteristics of two dimensional nanoscale sliding contacts between rigid multi-asperity tips and elastic textured surfaces are investigated. Four nanoscale textured surfaces with different texture shapes are designed, and six multi-asperity tips composed of cylindrical asperities with different radii are used to slide on the textured surfaces. Friction forces are compared for different tips, and effects of the asperity radii on the friction characteristics are investigated. Average friction forces for all the cases are listed and compared, and effects of texture shapes of the textured surfaces are discussed. The results show that textured surface II has a better structure to reduce friction forces. The multi-asperity tips composed of asperities with R=20r0 （r0=0.227 7 nm） or R=30r0 get higher friction forces compared with other cases, and more atoms of the textured surfaces are taken away by these two tips, which are harmful to reduce friction or wear. For the case of R=10ro, friction forces are also high due to large contact areas, but the sliding processes are stable and few atoms are taken away by the tip. The proposed research considers interactions between more asperities to make the model approach to the real sliding contact problems. The results will help to vary or even control friction characteristics by textured surfaces, or provide references to the design of textured surfaces.展开更多
BiFeGaO3-BaTiO3(BFG-BT)based ceramics with a large piezoelectric coefficient are potential high performance lead-free piezoelectric compounds.In this work,textured and random BFG-BT ceramics were realized by the solid...BiFeGaO3-BaTiO3(BFG-BT)based ceramics with a large piezoelectric coefficient are potential high performance lead-free piezoelectric compounds.In this work,textured and random BFG-BT ceramics were realized by the solid state reaction method with and without BaTiO3(BT)templates.Textured ceramics were obtained by a reactive templated grain growth(RTGG)method leading to a high-temperature electromechanical strain of S=0.27%at 40 kV/cm and to an effective piezoelectric coefficient(d33*)up to 685 pm/V at 180℃.The easy movement of oriented domains enhanced the electromechanical strain under an applied electric field in textured sample(Lotgering factor f=66.3%).Structural investigations reveal that the proportion and degree of distortion of BFG-BT rhombohedral phase(R3c)reached its maximum in textured ceramics,resulting in large ferrodistortive displacements under electric fields.In addition,the dense nanodomains with low domain wall energies,inferred from the high-resolution transmission electron microscope(HR-TEM)observations,contribute to the extra displacement of the textured sample under an applied electric field.In textured ceramics,the remnant polarization was stable(about 17μC/cm2)from room temperature to 180℃,contributing to the stable ferroelectric property at high temperatures.Through the introduction of BT templates,high-density nanodomains were formed and the Burns temperature was enhanced in textured ceramics.The electromechanical strain,polarization and dielectric behavior were correlated to the textured or random forms of the BFG-BT based ceramics.展开更多
Transparent conducting F-doped texture SnO2 films with resistivity as low as 5× 10-4 Ω ·cm,with carrier concentrations between 3.5 × 1020 and 7× 1020 cm-3 and Hall mobilities from 15.7 to 20.1 cm2...Transparent conducting F-doped texture SnO2 films with resistivity as low as 5× 10-4 Ω ·cm,with carrier concentrations between 3.5 × 1020 and 7× 1020 cm-3 and Hall mobilities from 15.7 to 20.1 cm2/(V/s) have been prepared by atmosphere pressure chemical vapour deposition (APCVD). These polycrystalline films possess a variable preferred orientation, the polycrystallite sizes and orientations vary with substrate temperature. The substrate temperature and fluorine flow rate dependence of conductivity, Hall mobility and carrier conentration fOr the resultingfilms have been obtained. The temperature dependence of the mobiity and carrier concentrationhave been measured over a temperature range 16～400 K. A systematically theoretical analysis on scattering mechanisms for the highly conductive SnO2 films has been given. Both theoretical analysis and experimental results indicate that for these degenerate, polycrystalline SnO2 ：F films in the low temperature range (below 100 K), ionized impurity scattering is main scattering mechanism. However, when the temperature is higher than 100 K, the lattice vibration scattering becomes dominant. The grain boundary scattering makes a small contribution to limit the mobility of the films.展开更多
The use of textured surfaces in lubrication to improve the tribological characteristics has been widely studied. The understanding of the textured surface geometric parameters influences on these tribological characte...The use of textured surfaces in lubrication to improve the tribological characteristics has been widely studied. The understanding of the textured surface geometric parameters influences on these tribological characteristics could help to improve their applications in industry. In this paper, we purpose to analyze the influence of the micro-texture depth on the friction coefficient experimentally. The experiment is conducted using different copper alloy samples have been the first laser textured with different micro-hole depth (40.83 μm and 46.36 μm). A 3D electronic Olympus microscope is used to visualize the shapes of the holes and find the depths. Then, the friction test has been conducted using these samples with the same velocity. The time variation of the friction coefficient is plotted and analyzed. The analysis of time variation of the friction coefficient shows a reduction of friction coefficient with the increase of the micro-hole depth has been observed. In some cases, this reduction is significant.展开更多
Textured surfaces are widely used in engineering components as they can improve tribological properties of sliding contacts, while the detailed behaviors of nanoscale reciprocating sliding contacts of textured surface...Textured surfaces are widely used in engineering components as they can improve tribological properties of sliding contacts, while the detailed behaviors of nanoscale reciprocating sliding contacts of textured surfaces are still lack of study. By using multiscale method, two dimensional nanoscale reciprocating sliding contacts of textured surfaces are investigated. The influence of indentation depth, texture shape, texture spacing, and tip radius on the average friction forces and the running-in stages is studied. The results show that the lowest indentation depth can make all the four textured surfaces reach steady state. Surfaces with right-angled trapezoid textures on the right side are better for reducing the running-in stage, and surfaces with right-angled trapezoid textures on the left side are better to reduce wear. Compared with other textured surfaces, the total average friction forces can be reduced by 82.94%–91.49% for the case of the contact between the tip with radius R = 60rand the isosceles trapezoid textured surface. Besides,the total average friction forces increase with the tip radii due to that bigger tip will induce higher contact areas. This research proposes a detailed study on nanoscale reciprocating sliding contacts of textured surfaces, to contribute to design textured surfaces, reduce friction and wear.展开更多
A nonepitaxial （001） textured Fe-Pt alloyed film was obtained by annealing Fe/Pt multilayers in H2. No Such nonepitaxial （001） texture was observed for similar multilayers annealed in N2 atmosphere. Sensitive elec...A nonepitaxial （001） textured Fe-Pt alloyed film was obtained by annealing Fe/Pt multilayers in H2. No Such nonepitaxial （001） texture was observed for similar multilayers annealed in N2 atmosphere. Sensitive electron energy loss spectroscopy and the left shift of the L10 FePt （111） diffr cfion peak indicate oxidation in the N2 annealed samples. The oxidation dramatically degrades the （001） texture of the Fe-Pt fdm and induces the composition change in the alloyed layer. The relation between the texture formation and oxidation was discussed.展开更多
CeO2/YSZ/CeO2 buffer layers were deposited on biaxially textured Ni substrates by pulsed laser deposition. The influence of the processing parameters on the texture development of the seed layer CeO2 was investigated....CeO2/YSZ/CeO2 buffer layers were deposited on biaxially textured Ni substrates by pulsed laser deposition. The influence of the processing parameters on the texture development of the seed layer CeO2 was investigated. Epitaxial films of YBCO were then grown in situ on the CeO2/YSZ （yttria-stabilized ZrO2）/CeO2-buffered Ni substrates. The resulting YBCO conductors exhibited self-fleld critical current density Jc of more than 1 MA/cm^2 at 77K and superconducting transition temperature Tc of about 91K.展开更多
基金supported by the Research Grants Council of the Hong Kong Special Administrative Region,China(16205721)the PolyU Start-up Fund(1-BDC4)。
文摘Dendrite formation and side reactions,which originate from uncontrolled zinc(Zn)nucleation and growth and high water activity,remain the two critical challenges that hinder the practical implementation of Zn anodes for rechargeable aqueous batteries.In this work,we propose a cation and anion comodulation strategy to realize highly textured and durable Zn anodes.As a proof of concept,1-ethyl-1-methylpyrrolidinium bromide(MEPBr)is selected as a versatile additive to regulate Zn deposition.Specifically,MEP^(+)cations with preferential adsorption on tips/edges first promote uniform primary Zn nucleation on the substrate,followed by dynamic“edge shielding”of existing deposits to guide highly oriented Zn growth.Meanwhile,the incorporation of Br^(-)anions promotes the enrichment of Zn^(2+)at the electrode-electrolyte interface(EEI),thereby facilitating Zn deposition kinetics.In addition,both the preferentially adsorbed MEP^(+)cations and Br^(-)anions create a water-poor EEI while the two ionic species disrupt the original hydrogen bond network and reduce water within the solvation structure in the bulk electrolyte through ion-water interactions,thus dramatically reducing water-induced side reactions.As a result,the Zn//Zn symmetric battery with the MEPBr-modulated electrolyte exhibits a remarkable lifespan of over 4000 h at 2 m A cm^(-2)and 1 mA h cm^(-2).More excitingly,the newly designed electrolyte enables a Zn//NaV_(3)O_(8)·1.5H_(2)O full battery with a thin Zn anode(50μm)and a high mass-loading cathode(~10 mg cm^(-2))to operate normally for over 300 cycles with remarkable capacity retention,showcasing its great potential for practical applications.
基金supported by the National Natural Science Foundation of China(Nos.51974196,52275361,and 52305406)the Key Projects of the National Natural Science Foundation of China(No.U22A20188)the Special Projects of the Central Government in Guidance of Local Science and Technology Development(YDZX20191400002149).
文摘The textured roll and polished roll were applied instead of the ground roll in a 20-high mill to conduct two-pass rolling of 316L stainless steel strip with thickness of 0.027 mm.After the two-pass rolling with the textured roll and polished roll(TPR),the surface roughness of the strip is dramatically reduced,and the surface topographical anisotropy index is diminished to 30.9%of the initial strip.Comparing with the strip rolled using the ground roll in both passes(GGR),the elongation of TPR rolled strip is obviously improved,and the mechanical property anisotropy is greatly weakened.The anisotropy index of tensile strength and elongation are 42.58%and 52.59%of that of GGR rolled strip,which is mainly attributed to the significant decrease of the texture intensity of the strip by TPR process.The results indicate that TPR process can obtain the stainless steel ultra-thin strip with smooth and uniform surface topography and good mechanical properties.
基金supports from the projects by the NSFC[51771166]the Hebei Natural Science Foundation[E2019203452,E2021203011]+3 种基金the key project of department of education of Hebei province[ZD2021107]project of the central government guiding local science and technology development[216Z1001G]Cultivation Project for Basic Research and Innovation of Yanshan University[2021LGZD002]project of State Key Laboratory of Materials Processing and Die&Mould Technology[P2023-004]are gratefully acknowledged.
文摘Molecular dynamics(MD)simulation is employed to investigate the deformation behavior under various loading paths and strain rates of nanocrystalline magnesium(NC Mg)with[0001]texture.Atomic-scale structural evolution of NC Mg was performed under uniaxial and biaxial loadings.In tension process,compression twins and basal slip dominate,while the compression process is dominated by tension twins.The activation mechanism of twinning is highly sensitive to the loading path and grain orientation.Meanwhile,the effect of strain rate on the structural evolution of NC Mg was investigated.It is found that the effect of strain rate on the plastic deformation of NC Mg is reflected through the plasticity delays and the way to release the stress.As the strain rate decreases,the plastic deformation mechanism gradually changes from intragranular to grain boundary.Some significant potential deformation mechanisms in the loading process were studied.It is observed that{1121}twins nucleated inside the grains,and the thickening process is completed by basal〈a〉slip of the twin boundary.The strain compatibility between twins is automatically optimized with loading.Moreover,the detwinning mechanism caused by the interaction between twins and basal stacking faults is clarified.
文摘Magnesium alloys have many advantages as lightweight materials for engineering applications,especially in the fields of automotive and aerospace.They undergo extensive cutting or machining while making products out of them.Dry cutting,a sustainable machining method,causes more friction and adhesion at the tool-chip interface.One of the promising solutions to this problem is cutting tool surface texturing,which can reduce tool wear and friction in dry cutting and improve machining performance.This paper aims to investigate the impact of dimple textures(made on the flank face of cutting inserts)on tool wear and chip morphology in the dry machining of AZ31B magnesium alloy.The results show that the cutting speed was the most significant factor affecting tool flank wear,followed by feed rate and cutting depth.The tool wear mechanism was examined using scanning electron microscope(SEM)images and energy dispersive X-ray spectroscopy(EDS)analysis reports,which showed that at low cutting speed,the main wear mechanism was abrasion,while at high speed,it was adhesion.The chips are discontinuous at low cutting speeds,while continuous at high cutting speeds.The dimple textured flank face cutting tools facilitate the dry machining of AZ31B magnesium alloy and contribute to ecological benefits.
基金supported by National Natural Science Foundation of China(52175431)Natural Science Foundation of Tianjin of China(22JCZDJC00730).
文摘Cutting tools are known as the“productivity”of the manufacturing industry,which affects the production efficiency and quality of the workpiece,and has become the focus of research and attention in academia and industry.However,traditional cutting tools often suffer from adhesion or wear during the cutting process,which considerably reduces the cutting efficiency and service life of the tools,and makes it difficult to meet current production requirements.To solve the above problems,scholars have introduced bionics into the tool’s design,applying the microscopic structure of the biological surface to the tool surface to alleviate the tool’s failure.This paper mainly summarizes the research progress of bionic textured cutting tools.Firstly,categorize whether the bionic texture design is inspired by a single organism or multiple organisms.Secondly,it is discussed that the non-smooth surface of the biological surface has five characteristics:hydrophilic lubricity,wear resistance,drag reduction and hydrophobicity,anti-adhesion,and arrangement,and the non-smooth structure of these different characteristics are applied to the surface of the tool is designed with bionic texture.Furtherly,the cutting performance of bionic textured cutting tools is discussed.The anti-friction and wear-resisting mechanism of bionic textured cutting tools is analyzed.Finally,some pending problems and perspectives have been proposed to provide new inspirations for the design of bionic textured cutting tools.
基金supported by the National Natural Science Foun-dation of China under Grant No.11704249the Natural Science Foundation of Shaanxi Provincial Department of Education under Grant No.20JK0667the President’s Fund of Xi’an Technologi-cal University under Grant No.XGPY200204.
文摘In this work,texturing is proposed to improve the piezoelectric response of PSN-PMN-PT ceramics.The PSN-PMN-PT textured ceramic with a Lotgering factor F001 higher than 99%was synthesized by the liquid-phase-assisted template grain growth(TGG)method.The addition of CuO/B2 O3 sintering aids improves the BT templates induced grain orientation growth behavior significantly.In comparison with its random counterpart,the Cu/B-T textured ceramic exhibits a high Lotgering factor F001 of 99%and significantly enhanced dielectric and piezoelectric responses:ε_(r)~3100,tanδ~0.8%,d_(33)~1030 pC N^(-1),d_(33)·g_(33)~34.2×10^(-12) m^(2) N^(-1),d_(33)∗~1490 pm V^(-1)@5 kV cm^(-1),Smax~0.26%@20 kV cm^(-1) and H_(s)~8.5%.In the meantime,good temperature stability is observed in the Cu/B-T textured ceramic with a variation of d_(33)∗@20 kV cm^(-1) and annealed d_(33) lower than 9.68%and 18.1%over a wide temperature range of 25-140°C.This work shows that PSN-PMN-PT textured ceramic(Cu/B-T)has great potential for electrome-chanical device applications such as precision actuators,ultrasound transducers,and energy harvesters.
文摘Along with the increasing demand on exterior wall cladding as a protective cover for the interior elements and an indicator for modernity and architectural innovation,comes the need to develop new cladding materials that can replace the old ones and overcome their setbacks.This paper discusses the possibility of replacing stone by textured concrete as a cladding material in order to overcome the main challenges faced stone cladding by comparing them together.The comparison was made based on the main requirements of the cladding materials namely:economic,environmental,social,functional and structural aspects.
基金supported in part by the Natural Science Foun-dation of Heilongjiang Province(No.LH2022E048)Postdoctoral Science Foundation of Heilongjiang Province(No.LBH-Z22138)China National Postdoctoral Program for Innovative Talents(No.BX20490103).
文摘<001>textured Pb(Ni_(1/3)Nb_(2/3))O_(3)-PbZrO_(3)-PbTiO_(3)(PNN-PZT)ceramics were prepared by templated grain growth(TGG)technique using 0.36PNN-x PZ-(0.64-x)PT(x=0.23,0.25 and 0.27)powder matrix.Optimum template content was derived to achieve the best electromechanical properties of textured ceramics.The piezoelectric coefficient d33=1165 pC/N,Curie temperature T_(C)=197℃,longitudinal mode electrome-chanical coupling factor k33=0.86 and a very large effective piezoelectric strain coefficient d_(33)^(*)=2041 pm/V were simultaneously achieved at the morphotropic phase boundary(MPB)composition(x=0.25)with 3 vol.%BaTiO_(3)(BT)templates.Domain structures of textured ceramics were analyzed in detail to reveal the origin of these high piezoelectric and electromechanical properties.
基金Supported by National Natural Science Foundation of China(Grant No.52075438)Key Research and Development Program of Shaanxi Province of China(Grant No.2024GX-YBXM-268)Open Project of State Key Laboratory for Manufacturing Systems Engineering of China(Grant No.sklms2020010).
文摘In this study,a machine vision method is proposed to characterize 3D roughness of the textured surface on cylinder liner processed by plateau honing.The least absolute value(L∞)regression robust algorithm and Levenberg-Marquardt(LM)algorithm are employed to reconstruct image reference plane.On this basis,a single-hidden layer feedforward neural network(SLFNN)based on the extreme learning machine(ELM)is employed to model the relationship between high frequency information and 3D roughness.The characteristic parameters of Abbott-Firestone curve and 3D roughness measured by a confocal microscope are used to construct ELM-SLFNN prediction model for 3D roughness.The results indicate that the proposed method can effectively characterize 3D roughness of the textured surface of cylinder liner.
基金Project(CSTC2010AA4035)supported by Scientific and Technological Project of Chongqing Science and Technology Commission,ChinaProject(50504019)supported by the National Natural Science Foundation of China+1 种基金Project(CDJZR11130008)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(CDJXS10130001)supported by the Chongqing University Postgraduates'Science and Innovation Fund,China
文摘Repeated unidirectional bending （RUB） was carried out to improve the texture of commercial AZ31B magnesium alloy sheets. All specimens were prepared in the rolling direction. The forming limit diagrams （FLDs） of AZ31B magnesium alloy sheet were determined experimentally by conducting stretch-forming tests at room temperature, 100, 200 and 300 ℃ Compared with the as-received sheet, the lowest limited strain of AZ31B magnesium alloy sheet with tilted texture in the FLD increased by 79% at room temperature and 104% at 100 ℃. The texture also affected the extension of the forming limit curves （FLC） in the FLD. However, the FLCs of two kinds of sheets almost overlapped at temperature above 200 ℃. It can be concluded that the reduction of （0002） texture intensity is effective to the improvement of formability not only at room temperature but also at low-and-medium temperature. The effect of texture on FLDs becomes weak with increasing temperature.
基金Projects(51221001,50972121)supported by the National Natural Science Foundation of ChinaProject(B08040)supported by the Introducing Talents of Discipline to Universities,ChinaProject(11-BZ-2012)supported by the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China
文摘Short carbon fiber felts with an initial porosity of 89.5% were deposited by isobaric, isothermal chemical vapor infiltration using natural gas as carbon source. The bulk density of the deposited carbon/carbon （C/C） composites was 1.89 g/cm3 after depositing for 150 h. The microstructure and mechanical properties of the C/C composites were studied by polarized light microscopy, X-ray diffraction, scanning electron microscopy and three-point bending test. The results reveal that high textured pyrolytic carbon is deposited as the matrix of the composites, whose crystalline thickness and graphitization degree highly increase after heat treatment. A distinct decrease of the flexural strength and modulus accompanied by the increase of the toughness of the C/C composites is found to be correlated with the structural changes in the composites during the heat treatment process.
基金Supported by National Natural Science Foundation of China(Grant Nos.51205313,50975232)Fundamental Research Funds for the Central Universities of China(Grant No.3102014JCS05009)the 111 Project of China(Grant No.B13044)
文摘Detailed behaviors of nanoscale textured surfaces during the reciprocating sliding contacts are still unknown although they are widely used in mechanical components to improve tribological characteristics.The current research of sliding contacts of textured surfaces mainly focuses on the experimental studies,while the cost is too high.Molecular dynamics(MD)simulation is widely used in the studies of nanoscale single-pass sliding contacts,but the CPU cost of MD simulation is also too high to simulate the reciprocating sliding contacts.In this paper,employing multiscale method which couples molecular dynamics simulation and finite element method,two dimensional nanoscale reciprocating sliding contacts of textured surfaces are investigated.Four textured surfaces with different texture shapes are designed,and a rigid cylindrical tip is used to slide on these textured surfaces.For different textured surfaces,average potential energies and average friction forces of the corresponding sliding processes are analyzed.The analyzing results show that"running-in"stages are different for each texture,and steady friction processes are discovered for textured surfaces II,III and IV.Texture shape and sliding direction play important roles in reciprocating sliding contacts,which influence average friction forces greatly.This research can help to design textured surfaces to improve tribological behaviors in nanoscale reciprocating sliding contacts.
基金This work was supported by the Postdoctoral Science Foundation(Nos.BX20490103,2020M681089,LBH-Z19065 and LBHZ13109)the National Natural Science Foundation of China(No.52002093).
文摘Textured BaTiO_(3)(BT)-based lead-free ceramics have gained significant attention due to their high piezoelectric coefficient(d)and very large field induced strain(S).However,costly nano-size raw materials,excessively high sintering temperature and low Curie temperature(T_(c))hinder their device applications.In this work,highly[001]_(c)-oriented(Ba_(0.95)Ca_(0.05))(Zr_(0.04)Ti_(0.96))O_(3) ceramics with x mol%CuO(x=0.25,0.5,1.0,2.5)denoted as BCZT-x were synthesized by templated grain growth using micro-sized raw powders.The introduction of CuO sintering agent lowered the sintering temperature by 125℃ to 1450℃,and the BCZT-1.0 achieved a high texture degree of∼99%.In addition,the CuO-based liquid phases eliminated boundaries between BT templates and BCZT matrix powders.Such liquid-phase sintering reduced sintering stresses,decreased the average grain size of BCZT-1.0 from 16μm down to 13μm,and increased the dielectric dispersion coefficientγto 1.63.The almost smoothed out T_(O-T) anomaly in the temperature dependence of dielectric permittivity and comparably high T_(c)(>102℃)lead to better temperature stability.The narrower grain orientation distribution with full width at half maximum(FWHM)of∼5.9°and smaller domains with the size of 0.1–0.5μm in width and 3–8μm in length were obtained,a high field induced maximum strain S_(max) of 0.38%and low H_(s) of 5.2%have been achieved in BCZT-1.0 textured ceramics together with a high and homogeneous piezoelectric stress coefficient d_(33)∼780 pC/N and very large d_(33)∗∼2950 pm/V.
基金supported by National Natural Science Foundation of China(Grant Nos.51205313,50975232)111 Project(Grant No.B13044)Northwestern Polytechnical University Foundation for Fundamental Research,China(Grant No.JC20110249)
文摘Nanoscale sliding contacts of smooth surfaces or between a single asperity and a smooth surface have been widely investigated by molecular dynamics simulations, while there are few studies on the sliding contacts between two rough surfaces. Actually, the friction of two rough surfaces considering interactions between more asperities should be more realistic. By using multiscale method, friction characteristics of two dimensional nanoscale sliding contacts between rigid multi-asperity tips and elastic textured surfaces are investigated. Four nanoscale textured surfaces with different texture shapes are designed, and six multi-asperity tips composed of cylindrical asperities with different radii are used to slide on the textured surfaces. Friction forces are compared for different tips, and effects of the asperity radii on the friction characteristics are investigated. Average friction forces for all the cases are listed and compared, and effects of texture shapes of the textured surfaces are discussed. The results show that textured surface II has a better structure to reduce friction forces. The multi-asperity tips composed of asperities with R=20r0 （r0=0.227 7 nm） or R=30r0 get higher friction forces compared with other cases, and more atoms of the textured surfaces are taken away by these two tips, which are harmful to reduce friction or wear. For the case of R=10ro, friction forces are also high due to large contact areas, but the sliding processes are stable and few atoms are taken away by the tip. The proposed research considers interactions between more asperities to make the model approach to the real sliding contact problems. The results will help to vary or even control friction characteristics by textured surfaces, or provide references to the design of textured surfaces.
基金financially supported by the National Key R&D Program of China(Nos.2016YFB0402701 and 2016YFA0201103)the National Basic Research Program of China(No.2015CB654605)+1 种基金the National Natural Science Foundation of China(Nos.51831010 and 51672293)the Instrument Developing Project of Chinese Academy of Sciences(No.ZDKYYQ20180004)。
文摘BiFeGaO3-BaTiO3(BFG-BT)based ceramics with a large piezoelectric coefficient are potential high performance lead-free piezoelectric compounds.In this work,textured and random BFG-BT ceramics were realized by the solid state reaction method with and without BaTiO3(BT)templates.Textured ceramics were obtained by a reactive templated grain growth(RTGG)method leading to a high-temperature electromechanical strain of S=0.27%at 40 kV/cm and to an effective piezoelectric coefficient(d33*)up to 685 pm/V at 180℃.The easy movement of oriented domains enhanced the electromechanical strain under an applied electric field in textured sample(Lotgering factor f=66.3%).Structural investigations reveal that the proportion and degree of distortion of BFG-BT rhombohedral phase(R3c)reached its maximum in textured ceramics,resulting in large ferrodistortive displacements under electric fields.In addition,the dense nanodomains with low domain wall energies,inferred from the high-resolution transmission electron microscope(HR-TEM)observations,contribute to the extra displacement of the textured sample under an applied electric field.In textured ceramics,the remnant polarization was stable(about 17μC/cm2)from room temperature to 180℃,contributing to the stable ferroelectric property at high temperatures.Through the introduction of BT templates,high-density nanodomains were formed and the Burns temperature was enhanced in textured ceramics.The electromechanical strain,polarization and dielectric behavior were correlated to the textured or random forms of the BFG-BT based ceramics.
文摘Transparent conducting F-doped texture SnO2 films with resistivity as low as 5× 10-4 Ω ·cm,with carrier concentrations between 3.5 × 1020 and 7× 1020 cm-3 and Hall mobilities from 15.7 to 20.1 cm2/(V/s) have been prepared by atmosphere pressure chemical vapour deposition (APCVD). These polycrystalline films possess a variable preferred orientation, the polycrystallite sizes and orientations vary with substrate temperature. The substrate temperature and fluorine flow rate dependence of conductivity, Hall mobility and carrier conentration fOr the resultingfilms have been obtained. The temperature dependence of the mobiity and carrier concentrationhave been measured over a temperature range 16～400 K. A systematically theoretical analysis on scattering mechanisms for the highly conductive SnO2 films has been given. Both theoretical analysis and experimental results indicate that for these degenerate, polycrystalline SnO2 ：F films in the low temperature range (below 100 K), ionized impurity scattering is main scattering mechanism. However, when the temperature is higher than 100 K, the lattice vibration scattering becomes dominant. The grain boundary scattering makes a small contribution to limit the mobility of the films.
文摘The use of textured surfaces in lubrication to improve the tribological characteristics has been widely studied. The understanding of the textured surface geometric parameters influences on these tribological characteristics could help to improve their applications in industry. In this paper, we purpose to analyze the influence of the micro-texture depth on the friction coefficient experimentally. The experiment is conducted using different copper alloy samples have been the first laser textured with different micro-hole depth (40.83 μm and 46.36 μm). A 3D electronic Olympus microscope is used to visualize the shapes of the holes and find the depths. Then, the friction test has been conducted using these samples with the same velocity. The time variation of the friction coefficient is plotted and analyzed. The analysis of time variation of the friction coefficient shows a reduction of friction coefficient with the increase of the micro-hole depth has been observed. In some cases, this reduction is significant.
基金Supported by National Natural Science Foundation of China(Grant Nos.51675429,51205313)Fundamental Research Funds for the Central Universities,China(Grant No.3102014JCS05009)the 111 Project,China(Grant No.B13044)
文摘Textured surfaces are widely used in engineering components as they can improve tribological properties of sliding contacts, while the detailed behaviors of nanoscale reciprocating sliding contacts of textured surfaces are still lack of study. By using multiscale method, two dimensional nanoscale reciprocating sliding contacts of textured surfaces are investigated. The influence of indentation depth, texture shape, texture spacing, and tip radius on the average friction forces and the running-in stages is studied. The results show that the lowest indentation depth can make all the four textured surfaces reach steady state. Surfaces with right-angled trapezoid textures on the right side are better for reducing the running-in stage, and surfaces with right-angled trapezoid textures on the left side are better to reduce wear. Compared with other textured surfaces, the total average friction forces can be reduced by 82.94%–91.49% for the case of the contact between the tip with radius R = 60rand the isosceles trapezoid textured surface. Besides,the total average friction forces increase with the tip radii due to that bigger tip will induce higher contact areas. This research proposes a detailed study on nanoscale reciprocating sliding contacts of textured surfaces, to contribute to design textured surfaces, reduce friction and wear.
基金This work was financially supported by the National High-Tech Research and Development Program of China ("863" Program, No. 2002AA302103)
文摘A nonepitaxial （001） textured Fe-Pt alloyed film was obtained by annealing Fe/Pt multilayers in H2. No Such nonepitaxial （001） texture was observed for similar multilayers annealed in N2 atmosphere. Sensitive electron energy loss spectroscopy and the left shift of the L10 FePt （111） diffr cfion peak indicate oxidation in the N2 annealed samples. The oxidation dramatically degrades the （001） texture of the Fe-Pt fdm and induces the composition change in the alloyed layer. The relation between the texture formation and oxidation was discussed.
文摘CeO2/YSZ/CeO2 buffer layers were deposited on biaxially textured Ni substrates by pulsed laser deposition. The influence of the processing parameters on the texture development of the seed layer CeO2 was investigated. Epitaxial films of YBCO were then grown in situ on the CeO2/YSZ （yttria-stabilized ZrO2）/CeO2-buffered Ni substrates. The resulting YBCO conductors exhibited self-fleld critical current density Jc of more than 1 MA/cm^2 at 77K and superconducting transition temperature Tc of about 91K.
