AIM:To investigate the impact of hsa_circ_0007482 on the proliferation and apoptosis of human pterygium fibroblasts(HPFs)and its correlation with the severity grades of pterygium.METHODS:Pterygium and normal conjuncti...AIM:To investigate the impact of hsa_circ_0007482 on the proliferation and apoptosis of human pterygium fibroblasts(HPFs)and its correlation with the severity grades of pterygium.METHODS:Pterygium and normal conjunctival tissues were collected from the superior area of the same patient’s eye(n=33).The correlation between pterygium severity and hsa_circ_0007482 expression using quantitative reversetranscription polymerase chain reaction(RT-qPCR)were analyzed.Three distinct siRNA sequences targeting hsa_circ_0007482,along with a negative control sequence,were transfected into HPFs.Cell proliferation was assessed using the cell counting kit-8.Expression levels of Ki67,proliferating cell nuclear antigen(PCNA),Cyclin D1,Bax,B-cell lymphoma-2(Bcl-2),and Caspase-3 were measured via RT-qPCR.Immunofluorescence staining was employed to detect Ki67 and vimentin expressions.Apoptosis was evaluated using flow cytometry.RESULTS:Hsa_circ_0007482 expression was significantly higher in pterygium tissues compared to normal conjunctival tissues(P<0.001).Positive correlations were observed between hsa_circ_0007482 expression and pterygium severity,thickness,and vascular density.Knockdown of hsa_circ_0007482 inhibited cell proliferation,reducing the mRNA expression of Ki67,PCNA,and Cyclin D1 in HPFs.Hsa_circ_0007482 knockdown induced apoptosis,increasing mRNA expression levels of Bax and Caspase-3,while decreasing Bcl-2 expression in HPFs.Additionally,hsa_circ_0007482 knockdown attenuated vimentin expression in HPFs.CONCLUSION:The downregulation of hsa_circ_0007482 effectively hampers cell proliferation and triggers apoptosis in HPFs.There are discernible positive correlations detected between the expression of hsa_circ_0007482 and the severity of pterygium.展开更多
目的:比较两焦点(AT LISA 809MP)和三焦点(AT LISA tri 839MP)IOL植入术后的视觉质量。方法:回顾性研究。共收集2018-03/2019-02行超声乳化吸除术联合多焦点IOL植入术的白内障患者28例49眼。两焦点组18例30眼,年龄40~85(平均67.08±...目的:比较两焦点(AT LISA 809MP)和三焦点(AT LISA tri 839MP)IOL植入术后的视觉质量。方法:回顾性研究。共收集2018-03/2019-02行超声乳化吸除术联合多焦点IOL植入术的白内障患者28例49眼。两焦点组18例30眼,年龄40~85(平均67.08±10.80)岁。三焦点组10例19眼,年龄38~79(平均62.21±14.50)岁。所有患者均行视觉质量分析系统(OQAS)、离焦曲线等检查。结果:两焦点组近BCVA优于三焦点,三焦点组中UCVA和远BCVA均优于两焦点组(P<0.05)。三焦点组+1.5、-1.0、-1.5、-2.0、-2.5、-3.0D视力显著优于两焦点组。两组间OQAS视觉质量参数两焦点组OV 20%、OV 9%、SR均优于三焦点组(P<0.05)。结论:两焦点和三焦点IOL植入术后均可获得良好的裸眼远和近视力,视觉质量均较高,而三焦点IOL可获得更佳的中间视力。展开更多
A new horizontal continuous casting method with heating-cooling combined mold (HCCM) technology was explored for fabri- cating high-quality thin-wall cupronickel alloy tubes used for heat exchange pipes. The microst...A new horizontal continuous casting method with heating-cooling combined mold (HCCM) technology was explored for fabri- cating high-quality thin-wall cupronickel alloy tubes used for heat exchange pipes. The microstructure and mechanical properties of BFe 10 cupronickel alloy tubes fabricated by HCCM and traditional continuous casting (cooling mold casting) were comparatively investigated. The results show that the tube fabricated by HCCM has smooth internal and external surfaces without any defects, and its internal and external surface roughnesses are 0.64 μm and 0.85 μm, respectively. The tube could be used for subsequent cold processing without other treatments such as surface planning, milling and acid-washing. This indicates that HCCM can effectively reduce the process flow and improve the pro- duction efficiency of a BFel0 cupronickel alloy tube. The tube has columnar grains along its axial direction with a major casting texture of {012}〈 621 〉. Compared with cooling mold casting (6 = 36.5%), HCCM can improve elongation (3 = 46.3%) by 10% with a slight loss of strength, which indicates that HCCM remarkably improves the cold extension performance of a BFe 10 cupronickel alloy tube.展开更多
Based on horizontal continuous casting with a heating-cooling combined mold (HCCM) technology, this article investigated the effects of processing parameters on the liquid-solid interface (LSI) position and the in...Based on horizontal continuous casting with a heating-cooling combined mold (HCCM) technology, this article investigated the effects of processing parameters on the liquid-solid interface (LSI) position and the influence of LSI position on the surface quality, microstructure, texture, and mechanical properties of a BFe10-1-1 tube (φ50 mm × 5 mm). HCCM efficiently improves the temperature gradient in front of the LSI. Through controlling the LSI position, the radial columnar-grained microstructure that is commonly generated by cooling mold casting can be eliminated, and the axial columnar-grained microstructure can be obtained. Under the condition of 1250℃ melting and holding temperature, 1200-1250℃ mold heating temperature, 50-80 mm/min mean drawing speed, and 500-700 L/h cooling water flow rate, the LSI position is located at the middle of the transition zone or near the entrance of the cooling section, and the as-cast tube not only has a strong axial columnar-grained microstructure ({hkl}〈621〉, {hkl}〈221〉) due to strong axial heating conduction during solidification but also has smooth internal and external surfaces without cracks, scratches, and other macroscopic defects due to short solidified shell length and short contact length between the tube and the mold at high temperature. The elongation and tensile strength of the tube are 46.0%-47.2% and 210-221 MPa, respectively, which can be directly used for the subsequent cold-large-strain processing.展开更多
The steady-state temperature field of horizontal core-filling continuous casting (HCFC) for producing copper cladding aluminum rods was simulated by finite element method to investigate the effects of key processing...The steady-state temperature field of horizontal core-filling continuous casting (HCFC) for producing copper cladding aluminum rods was simulated by finite element method to investigate the effects of key processing parameters on the positions of solid-liquid interfaces (SLIs) of copper and aluminum. It is found that mandrel tube length and mean withdrawing speed have significant effects on the SLI positions of both copper and aluminum. Aluminum casting temperature (TAI) (1003-1123 K) and secondary cooling water flux (600-900 L.h-1) have little effect on the SLI of copper but cause the SLI of aluminum to move 2-4 mm. When TA1 is in a range of 1043-1123 K, the liquid aluminum can fill continuously into the pre-solidified copper tube. Based on the numerical simulation, reasonable processing parameters were determined.展开更多
Lotus-type porous copper was fabricated by unidirectional solidification, and compressive experiments were subsequently conducted in the strain rate range of 10-3-2400 s-1 with the compressive direction parallel to th...Lotus-type porous copper was fabricated by unidirectional solidification, and compressive experiments were subsequently conducted in the strain rate range of 10-3-2400 s-1 with the compressive direction parallel to the pores. A GLEEBLE-1500 thermal-mechanical simulation system and a split Hopkinson pressure bar (SHPB) were used to investigate the effect of strain rate on the compressive deforma-tion behaviors of lotus-type porous copper. The influence mechanism of strain rate was also analyzed by the strain-controlling method and by high-speed photography. The results indicated that the stress-strain curves of lotus-typed porous copper consist of a linear elastic stage, a plateau stage, and a densification stage at various strain rates. At low strain rate (〈1.0 s^-1), the strain rate had little influence on the stress-strain curves; but when the strain rate exceeded 1.0 s^-1, it was observed to strongly affect the plateau stage, showing obvious strain-rate-hardening characteristics. Strain rate also influenced the densification initial strain. The densification initial strain at high strain rate was less than that at low strain rate. No visible inhomogeneous deformation caused by shockwaves was observed in lotus-type porous copper during high-strain-rate deformation. However, at high strain rate, the bending deformation characteristics of the pore walls obviously differed from those at low strain rate, which was the main mechanism by which the plateau stress exhibited strain-rate sensitivity when the strain rate exceeded a certain value and exhibited less densification initial strain at high strain rate.展开更多
Heating-cooling combined mold(HCCM) horizontal continuous casting technology developed by our research group was used to produce high axial columnar-grained CuN i10 FeM n1 alloy tubes with different Fe contents. The...Heating-cooling combined mold(HCCM) horizontal continuous casting technology developed by our research group was used to produce high axial columnar-grained CuN i10 FeM n1 alloy tubes with different Fe contents. The effects of Fe content(1.08wt%–2.01wt%) on the microstructure, segregation, and flushing corrosion resistance in simulated flowing seawater as well as the mechanical properties of the alloy tubes were investigated. The results show that when the Fe content is increased from 1.08wt% to 2.01wt%, the segregation degree of Ni and Fe elements increases, and the segregation coefficient of Ni and Fe elements falls from 0.92 to 0.70 and from 0.92 to 0.63, respectively. With increasing Fe content, the corrosion rate of the alloy decreases initially and then increases. When the Fe content is 1.83wt%, the corrosion rate approaches the minimum and dense, less-defect corrosion films, which contain rich Ni and Fe elements, form on the surface of the alloy; these films effectively protect the α-matrix and reduce the corrosion rate. When the Fe content is increased from 1.08wt% to 2.01wt%, the tensile strength of the alloy tube increases from 204 MPa to 236 MPa, while the elongation to failure changes slightly about 46%, indicating the excellent workability of the CuNi10FeMn1 alloy tubes.展开更多
The effects of Ni content(0−2.10 wt.%)on the precipitated phase,strength and electrical conductivity of Cu−0.4wt.%Be alloy were investigated,and the influencing mechanism was analyzed.The results showed that the addit...The effects of Ni content(0−2.10 wt.%)on the precipitated phase,strength and electrical conductivity of Cu−0.4wt.%Be alloy were investigated,and the influencing mechanism was analyzed.The results showed that the addition of Ni promoted the precipitation of strengthening phase in the alloy and remarkably enhanced the strengthening effect.When the Ni content was increased from 0 to 2.10 wt.%,the strength of the aged alloy initially increased and then decreased,and approached the maximum when the Ni content was 1.50 wt.%.The peak-aging parameters of the alloy containing 1.50 wt.%Ni were the aging temperature of 400℃ and the aging time of 60 min,where the tensile strength and yield strength of the aged alloy were 611 and 565 MPa,respectively,which were 2.8 times and 6.1 times those of the alloy without Ni.The electrical conductivity of the alloy with Ni increased with the aging time,and decreased with the increase of Ni content.With an increase of the aging time at 400℃,phase transition sequence of the Cu−0.4Be−1.5Ni alloy wasγ″phase→γ′phase→γphase.For the aging time of 60 min,a large number of dispersed nano-scale coherentγ″phase andγ′phase formed in the alloy with a remarkable strengthening effect,which was mainly responsible for the high strength of the alloy.展开更多
Cu-0.36 wt.%Be-0.46 wt.%Co alloy plate with 300 mm in width and 10 mm in thickness prepared by heating-cooling combined mold(HCCM) horizontal continuous casting was cold rolled. Microstructure evolution and mechanical...Cu-0.36 wt.%Be-0.46 wt.%Co alloy plate with 300 mm in width and 10 mm in thickness prepared by heating-cooling combined mold(HCCM) horizontal continuous casting was cold rolled. Microstructure evolution and mechanical properties of the alloy as well as its deformation mechanism were investigated. The results showed that the as-cast alloy plate had columnar grains along the length direction, good surface quality and elongation of 35%, which was directly large-reduction cold rolled without surface treatment, and the accumulative cold rolling reduction reached 98%. When the reduction was small(20%), numerous dislocations and dislocation cells formed, and the deformation mechanism was dislocation slip. When the reduction was 40%, deformation twins appeared, and interactions between twins and dislocation cells induced strip-like dislocation cells. When the reduction exceeded 60%, shear bands formed and apparent crystal rotation in the micro-region happened. Further increasing the reduction, the amount of the shear bands rose and they interacted with each other, which refined the grains apparently. The tensile strength and hardness increased from 353 MPa and HV 119 of the as-cast alloy to 625 MPa and HV 208 with 95% reduction, respectively, and the elongation reduced from 35% to 7.6%. A process of HCCM horizontal continuous casting-cold rolling can work as a novel compact method to fabricate Cu-Be alloy sheet.展开更多
Copper-clad aluminum (CCA) flat bars produced by the continuous casting-rolling process were subjected to continuous induction heating annealing (CIHA), and the effects of induction heating temperature and holding...Copper-clad aluminum (CCA) flat bars produced by the continuous casting-rolling process were subjected to continuous induction heating annealing (CIHA), and the effects of induction heating temperature and holding time on the microstructure, interface, and mechanical properties of the fiat bars were investigated. The results showed that complete recrystallization of the copper sheath occurred under CIHA at 460℃ for 5 s, 480℃ for 3 s, or 500℃ for 1 s and that the average grain size in the copper sheath was approximately 10.0 μm. In the case of specimens subjected to CIHA at 460-500℃ for longer than 1 s, complete recrystallization occurred in the aluminum core. In the case of CIHA at 460-500℃ for 1-5 s, a continuous interracial layer with a thickness of 2.5-5.5 μm formed and the thickness mainly increased with increasing annealing temperature. After CIHA, the interracial layer consisted primarily of a Cu9A14 layer and a CuA12 layer; the average interface shear strength of the CCA flat bars treated by CIHA at 460-500℃ for 1-5 s was 45-52 MPa. After full softening annealing, the hardness values of the copper sheath and the aluminum core were HV 65 and HV 24, respectively, and the hardness along the cross section of the CCA flat bar was uniform.展开更多
The aim of the study is to evaluate the chemical crosslinking effects of the natural derived chitosan dialdehyde(OCS)on collagen.Fourier transform infrared(FTIR)spectroscopy,differential scanning calorimetry(DSC)and c...The aim of the study is to evaluate the chemical crosslinking effects of the natural derived chitosan dialdehyde(OCS)on collagen.Fourier transform infrared(FTIR)spectroscopy,differential scanning calorimetry(DSC)and circular dichroism(CD)measurements suggest that introducing OCS might not destroy the natural triple helix conformation of collagen but enhance the thermal-stability of collagen.展开更多
Dear Editor, It is known that microRNA let-7a can be useful for diagnosis and therapy of cancer, including prostate cancer (PCa).1 A recent article by Wang et al. 2 comprehensively showed that let-7al could inhibit...Dear Editor, It is known that microRNA let-7a can be useful for diagnosis and therapy of cancer, including prostate cancer (PCa).1 A recent article by Wang et al. 2 comprehensively showed that let-7al could inhibit the expression of insulin-like growth factor- 1 receptor (IGF 1 R) by directly targeting the T1 and T2 sites in the 3' untranslated region (3'UTR) of IGF 1R mRNA. Furthermore, they found that let-7a 1-mediated IGF I R downregulation was accompanied by attenuation of Elk1 activity and c-fos expression, inhibition of PC-3 cell proliferation, cell cycle arrest and induced apoptosis and that inhibition oflet-7al could up-regulate IGF 1R accompanied by an increase of Elk1 activity and c-fos expression,展开更多
Reasonable design and applications of graphene-based materials are supposed to be promising ways to tackle many fundamental problems emerging in lithium batteries,including suppression of electrode/electrolyte side re...Reasonable design and applications of graphene-based materials are supposed to be promising ways to tackle many fundamental problems emerging in lithium batteries,including suppression of electrode/electrolyte side reactions,stabilization of electrode architecture,and improvement of conductive component.Therefore,extensive fundamental research on this aspect has been performed so far.However,when it comes to large-scale industrial applications,the utilization of graphene-based materials progresses at a very slow pace.Namely,there presents a severe technological decoupling between academic research and industrial application,and there is an urgent need to link them.Herein,in order to address current issues of graphene-based materials used in lithium batteries,we present their latest advancements with stateof-the-art technologies.Potential applications of graphenebased materials in practical lithium batteries are highlighted and predicted to bridge the gap between the academic progress and industrial manufacture,thereby paving the way for accelerating the development of graphenebased material as well as lithium battery industry.展开更多
With the increasing consumption of fossil fuels,proton exchange membrane fuel cells(PEMFCs)have attracted considerable attention as green and sustainable energy conversion devices.The slow kinetics of the cathodic oxy...With the increasing consumption of fossil fuels,proton exchange membrane fuel cells(PEMFCs)have attracted considerable attention as green and sustainable energy conversion devices.The slow kinetics of the cathodic oxygen reduction reaction(ORR)has a major impact on the performance of PEMFCs,and although platinum(Pt)can accelerate the reaction rate of the ORR,the scarcity and high cost of Pt resources still limit the development of PEMFCs.Therefore,the development of low-cost high-performance ORR catalysts is essential for the commercial application and development of PEMFCs.This paper reviews the research progress of researchers on Pt-based ORR catalysts in recent years,including Pt/C catalysts,Pt-based alloy catalysts,Pt-based intermetallic compounds,and Pt-based single-atom catalysts(SACs),with a focus on Pt-based alloy catalysts with different nanostructures.We described in detail the difficulties and solutions in the research process of various ORR catalysts and explained the principle of their activity enhancement with density functional theory(DFT).In addition,an outlook on the development of Pt-based catalysts is given,and reducing the amount of Pt used and improving the performance of catalysts are the directions to work on in the coming period.展开更多
Lithium-iron manganese phosphates(LiFex Mn_(1-x)PO_(4),0.1<x<0.9)have the merits of high safety and high working voltage.However,they also face the challenges of insufficient conductivity and poor cycling stabil...Lithium-iron manganese phosphates(LiFex Mn_(1-x)PO_(4),0.1<x<0.9)have the merits of high safety and high working voltage.However,they also face the challenges of insufficient conductivity and poor cycling stability.Some progress has been achieved to solve these problems.Herein,we firstly summarized the influence of different electrolyte systems on the electrochemical performance of LiFexMn_(1-x)PO_(4),and then discussed the effect of element doping,lastly studied the influences of conductive layer coating and morphology control on the cycling stability.Finally,the prospects and challenges of developing high-cycling LiFexMn_(1-x)PO_(4) were proposed.展开更多
Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is regarded as the promising cathode for lithium-ion batteries(LIBs).However,the challenges such as safety issues and poor cycling performance have seriously hindered...Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is regarded as the promising cathode for lithium-ion batteries(LIBs).However,the challenges such as safety issues and poor cycling performance have seriously hindered its commercial applications.In order to overcome these difficulties,there has been extensive research and development of electrolyte modifications for high-energy-density LIBs with Ni-rich cathodes.Herein,this review introduces the research progress based on solvent additives,salt type additives and other electrolytes for LIBs with NCM811cathode materials and discusses how they control the interface stability.In particular,some recommendations for further modification of enhancing electrolyte stability and improving NCM811 electrochemical properties are summarized and proposed,which put forward new design rules for the screening and customizing ideal electrolyte additives for high performance NCM811 cathode-based LIBs.展开更多
The large-scale application of lithium metal batteries remains a challenge due to the hydrolysis of LiPF_(6),which can induce capacity fade and series of safety issues.Prof.Ma and his co-workers have designed a hydrop...The large-scale application of lithium metal batteries remains a challenge due to the hydrolysis of LiPF_(6),which can induce capacity fade and series of safety issues.Prof.Ma and his co-workers have designed a hydrophobic Li^(+)-solvated structure to obtain high performances lithium metal batteries.The specific functional groups of theadditive,hexafluoroisopropyl acrylate.展开更多
As the most mature portable power source,lithium-ion battery has become the mainstream of power source for electric vehicles(EVs)by virtue of its high energy density,long cycle life and relatively low cost.However,an ...As the most mature portable power source,lithium-ion battery has become the mainstream of power source for electric vehicles(EVs)by virtue of its high energy density,long cycle life and relatively low cost.However,an excellent battery management system remained to be a problem for the operational states monitoring and safety guarantee for EVs.In this paper,a function realization of multi-scale modeling is proposed based on cyber hierarchy and interactional network framework,realizing basic functions such as multi-scale mapping and cloud-based modeling.Furthermore,to solve the problem of limited computing capability of the conventional vehicle-end battery management system,the novel system consists of hierarchies of side,edge and cloud,which are designed to take on different computing tasks methodically and swap data iteratively,providing specific services for drivers,enterprise users,etc.Due to a series of promising features,this system has a large range of application scenarios as well as some critical bottlenecks,which will be discussed at the end of the article.Please check and confirm D.-B.Shan"is correctly identified in author group.It’s not correct.There is no"D.-B.Shan"in author group,please just remove it.展开更多
基金Supported by Guangdong Basic and Applied Basic Research Foundation (No.2021A1515111012).
文摘AIM:To investigate the impact of hsa_circ_0007482 on the proliferation and apoptosis of human pterygium fibroblasts(HPFs)and its correlation with the severity grades of pterygium.METHODS:Pterygium and normal conjunctival tissues were collected from the superior area of the same patient’s eye(n=33).The correlation between pterygium severity and hsa_circ_0007482 expression using quantitative reversetranscription polymerase chain reaction(RT-qPCR)were analyzed.Three distinct siRNA sequences targeting hsa_circ_0007482,along with a negative control sequence,were transfected into HPFs.Cell proliferation was assessed using the cell counting kit-8.Expression levels of Ki67,proliferating cell nuclear antigen(PCNA),Cyclin D1,Bax,B-cell lymphoma-2(Bcl-2),and Caspase-3 were measured via RT-qPCR.Immunofluorescence staining was employed to detect Ki67 and vimentin expressions.Apoptosis was evaluated using flow cytometry.RESULTS:Hsa_circ_0007482 expression was significantly higher in pterygium tissues compared to normal conjunctival tissues(P<0.001).Positive correlations were observed between hsa_circ_0007482 expression and pterygium severity,thickness,and vascular density.Knockdown of hsa_circ_0007482 inhibited cell proliferation,reducing the mRNA expression of Ki67,PCNA,and Cyclin D1 in HPFs.Hsa_circ_0007482 knockdown induced apoptosis,increasing mRNA expression levels of Bax and Caspase-3,while decreasing Bcl-2 expression in HPFs.Additionally,hsa_circ_0007482 knockdown attenuated vimentin expression in HPFs.CONCLUSION:The downregulation of hsa_circ_0007482 effectively hampers cell proliferation and triggers apoptosis in HPFs.There are discernible positive correlations detected between the expression of hsa_circ_0007482 and the severity of pterygium.
文摘目的:比较两焦点(AT LISA 809MP)和三焦点(AT LISA tri 839MP)IOL植入术后的视觉质量。方法:回顾性研究。共收集2018-03/2019-02行超声乳化吸除术联合多焦点IOL植入术的白内障患者28例49眼。两焦点组18例30眼,年龄40~85(平均67.08±10.80)岁。三焦点组10例19眼,年龄38~79(平均62.21±14.50)岁。所有患者均行视觉质量分析系统(OQAS)、离焦曲线等检查。结果:两焦点组近BCVA优于三焦点,三焦点组中UCVA和远BCVA均优于两焦点组(P<0.05)。三焦点组+1.5、-1.0、-1.5、-2.0、-2.5、-3.0D视力显著优于两焦点组。两组间OQAS视觉质量参数两焦点组OV 20%、OV 9%、SR均优于三焦点组(P<0.05)。结论:两焦点和三焦点IOL植入术后均可获得良好的裸眼远和近视力,视觉质量均较高,而三焦点IOL可获得更佳的中间视力。
基金supported by the National High Technology Research and Development Program of China (No.2011BAE23B00)
文摘A new horizontal continuous casting method with heating-cooling combined mold (HCCM) technology was explored for fabri- cating high-quality thin-wall cupronickel alloy tubes used for heat exchange pipes. The microstructure and mechanical properties of BFe 10 cupronickel alloy tubes fabricated by HCCM and traditional continuous casting (cooling mold casting) were comparatively investigated. The results show that the tube fabricated by HCCM has smooth internal and external surfaces without any defects, and its internal and external surface roughnesses are 0.64 μm and 0.85 μm, respectively. The tube could be used for subsequent cold processing without other treatments such as surface planning, milling and acid-washing. This indicates that HCCM can effectively reduce the process flow and improve the pro- duction efficiency of a BFel0 cupronickel alloy tube. The tube has columnar grains along its axial direction with a major casting texture of {012}〈 621 〉. Compared with cooling mold casting (6 = 36.5%), HCCM can improve elongation (3 = 46.3%) by 10% with a slight loss of strength, which indicates that HCCM remarkably improves the cold extension performance of a BFe 10 cupronickel alloy tube.
基金financial support of National Key Technology R&D Program of China (No.2011BAE23B00)
文摘Based on horizontal continuous casting with a heating-cooling combined mold (HCCM) technology, this article investigated the effects of processing parameters on the liquid-solid interface (LSI) position and the influence of LSI position on the surface quality, microstructure, texture, and mechanical properties of a BFe10-1-1 tube (φ50 mm × 5 mm). HCCM efficiently improves the temperature gradient in front of the LSI. Through controlling the LSI position, the radial columnar-grained microstructure that is commonly generated by cooling mold casting can be eliminated, and the axial columnar-grained microstructure can be obtained. Under the condition of 1250℃ melting and holding temperature, 1200-1250℃ mold heating temperature, 50-80 mm/min mean drawing speed, and 500-700 L/h cooling water flow rate, the LSI position is located at the middle of the transition zone or near the entrance of the cooling section, and the as-cast tube not only has a strong axial columnar-grained microstructure ({hkl}〈621〉, {hkl}〈221〉) due to strong axial heating conduction during solidification but also has smooth internal and external surfaces without cracks, scratches, and other macroscopic defects due to short solidified shell length and short contact length between the tube and the mold at high temperature. The elongation and tensile strength of the tube are 46.0%-47.2% and 210-221 MPa, respectively, which can be directly used for the subsequent cold-large-strain processing.
基金financially supported by the National High Technology Research and Development Program of China (No. 2013AA030706 and No. 2009AA03Z532)the Fundamental Research Funds for the Central Universities of China (No. FRF-TP-12-146A)
文摘The steady-state temperature field of horizontal core-filling continuous casting (HCFC) for producing copper cladding aluminum rods was simulated by finite element method to investigate the effects of key processing parameters on the positions of solid-liquid interfaces (SLIs) of copper and aluminum. It is found that mandrel tube length and mean withdrawing speed have significant effects on the SLI positions of both copper and aluminum. Aluminum casting temperature (TAI) (1003-1123 K) and secondary cooling water flux (600-900 L.h-1) have little effect on the SLI of copper but cause the SLI of aluminum to move 2-4 mm. When TA1 is in a range of 1043-1123 K, the liquid aluminum can fill continuously into the pre-solidified copper tube. Based on the numerical simulation, reasonable processing parameters were determined.
基金financially supported by the National Natural Science Foundation(No.50904004)
文摘Lotus-type porous copper was fabricated by unidirectional solidification, and compressive experiments were subsequently conducted in the strain rate range of 10-3-2400 s-1 with the compressive direction parallel to the pores. A GLEEBLE-1500 thermal-mechanical simulation system and a split Hopkinson pressure bar (SHPB) were used to investigate the effect of strain rate on the compressive deforma-tion behaviors of lotus-type porous copper. The influence mechanism of strain rate was also analyzed by the strain-controlling method and by high-speed photography. The results indicated that the stress-strain curves of lotus-typed porous copper consist of a linear elastic stage, a plateau stage, and a densification stage at various strain rates. At low strain rate (〈1.0 s^-1), the strain rate had little influence on the stress-strain curves; but when the strain rate exceeded 1.0 s^-1, it was observed to strongly affect the plateau stage, showing obvious strain-rate-hardening characteristics. Strain rate also influenced the densification initial strain. The densification initial strain at high strain rate was less than that at low strain rate. No visible inhomogeneous deformation caused by shockwaves was observed in lotus-type porous copper during high-strain-rate deformation. However, at high strain rate, the bending deformation characteristics of the pore walls obviously differed from those at low strain rate, which was the main mechanism by which the plateau stress exhibited strain-rate sensitivity when the strain rate exceeded a certain value and exhibited less densification initial strain at high strain rate.
基金the support from the National Key Technology R&D Program of China (No. 2011BAE23B00)the National Natural Science Foundation of China (Nos. 51104016 and 51504023the fund of the State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals (No. SKL-SPM- 201204)
文摘Heating-cooling combined mold(HCCM) horizontal continuous casting technology developed by our research group was used to produce high axial columnar-grained CuN i10 FeM n1 alloy tubes with different Fe contents. The effects of Fe content(1.08wt%–2.01wt%) on the microstructure, segregation, and flushing corrosion resistance in simulated flowing seawater as well as the mechanical properties of the alloy tubes were investigated. The results show that when the Fe content is increased from 1.08wt% to 2.01wt%, the segregation degree of Ni and Fe elements increases, and the segregation coefficient of Ni and Fe elements falls from 0.92 to 0.70 and from 0.92 to 0.63, respectively. With increasing Fe content, the corrosion rate of the alloy decreases initially and then increases. When the Fe content is 1.83wt%, the corrosion rate approaches the minimum and dense, less-defect corrosion films, which contain rich Ni and Fe elements, form on the surface of the alloy; these films effectively protect the α-matrix and reduce the corrosion rate. When the Fe content is increased from 1.08wt% to 2.01wt%, the tensile strength of the alloy tube increases from 204 MPa to 236 MPa, while the elongation to failure changes slightly about 46%, indicating the excellent workability of the CuNi10FeMn1 alloy tubes.
基金The authors would like to thank the support from the National Key R&D Programme of China(No.2016YFB0301404)the National Natural Science Foundation of China(51925401,92066205)the National Ten Thousand Talents Programme of China and Ningbo“Science and Technology Innovation 2025”major project(No.2019B10087).
文摘The effects of Ni content(0−2.10 wt.%)on the precipitated phase,strength and electrical conductivity of Cu−0.4wt.%Be alloy were investigated,and the influencing mechanism was analyzed.The results showed that the addition of Ni promoted the precipitation of strengthening phase in the alloy and remarkably enhanced the strengthening effect.When the Ni content was increased from 0 to 2.10 wt.%,the strength of the aged alloy initially increased and then decreased,and approached the maximum when the Ni content was 1.50 wt.%.The peak-aging parameters of the alloy containing 1.50 wt.%Ni were the aging temperature of 400℃ and the aging time of 60 min,where the tensile strength and yield strength of the aged alloy were 611 and 565 MPa,respectively,which were 2.8 times and 6.1 times those of the alloy without Ni.The electrical conductivity of the alloy with Ni increased with the aging time,and decreased with the increase of Ni content.With an increase of the aging time at 400℃,phase transition sequence of the Cu−0.4Be−1.5Ni alloy wasγ″phase→γ′phase→γphase.For the aging time of 60 min,a large number of dispersed nano-scale coherentγ″phase andγ′phase formed in the alloy with a remarkable strengthening effect,which was mainly responsible for the high strength of the alloy.
基金Project(2016YFB0301404)supported by the National Key R&D Program of China。
文摘Cu-0.36 wt.%Be-0.46 wt.%Co alloy plate with 300 mm in width and 10 mm in thickness prepared by heating-cooling combined mold(HCCM) horizontal continuous casting was cold rolled. Microstructure evolution and mechanical properties of the alloy as well as its deformation mechanism were investigated. The results showed that the as-cast alloy plate had columnar grains along the length direction, good surface quality and elongation of 35%, which was directly large-reduction cold rolled without surface treatment, and the accumulative cold rolling reduction reached 98%. When the reduction was small(20%), numerous dislocations and dislocation cells formed, and the deformation mechanism was dislocation slip. When the reduction was 40%, deformation twins appeared, and interactions between twins and dislocation cells induced strip-like dislocation cells. When the reduction exceeded 60%, shear bands formed and apparent crystal rotation in the micro-region happened. Further increasing the reduction, the amount of the shear bands rose and they interacted with each other, which refined the grains apparently. The tensile strength and hardness increased from 353 MPa and HV 119 of the as-cast alloy to 625 MPa and HV 208 with 95% reduction, respectively, and the elongation reduced from 35% to 7.6%. A process of HCCM horizontal continuous casting-cold rolling can work as a novel compact method to fabricate Cu-Be alloy sheet.
基金financial support from the National High-Tech Research and Development Program of China (No. 2013AA030706)Beijing Science and Technology Project (No. Z141100004214003)Yunnan Province Sciencial and Technology Cooperation Project (No. 2015IB012)
文摘Copper-clad aluminum (CCA) flat bars produced by the continuous casting-rolling process were subjected to continuous induction heating annealing (CIHA), and the effects of induction heating temperature and holding time on the microstructure, interface, and mechanical properties of the fiat bars were investigated. The results showed that complete recrystallization of the copper sheath occurred under CIHA at 460℃ for 5 s, 480℃ for 3 s, or 500℃ for 1 s and that the average grain size in the copper sheath was approximately 10.0 μm. In the case of specimens subjected to CIHA at 460-500℃ for longer than 1 s, complete recrystallization occurred in the aluminum core. In the case of CIHA at 460-500℃ for 1-5 s, a continuous interracial layer with a thickness of 2.5-5.5 μm formed and the thickness mainly increased with increasing annealing temperature. After CIHA, the interracial layer consisted primarily of a Cu9A14 layer and a CuA12 layer; the average interface shear strength of the CCA flat bars treated by CIHA at 460-500℃ for 1-5 s was 45-52 MPa. After full softening annealing, the hardness values of the copper sheath and the aluminum core were HV 65 and HV 24, respectively, and the hardness along the cross section of the CCA flat bar was uniform.
文摘The aim of the study is to evaluate the chemical crosslinking effects of the natural derived chitosan dialdehyde(OCS)on collagen.Fourier transform infrared(FTIR)spectroscopy,differential scanning calorimetry(DSC)and circular dichroism(CD)measurements suggest that introducing OCS might not destroy the natural triple helix conformation of collagen but enhance the thermal-stability of collagen.
基金This work was supported by the National Science Foundation of China (No. 21272008, No. 81072686, No. 81273526).
文摘Dear Editor, It is known that microRNA let-7a can be useful for diagnosis and therapy of cancer, including prostate cancer (PCa).1 A recent article by Wang et al. 2 comprehensively showed that let-7al could inhibit the expression of insulin-like growth factor- 1 receptor (IGF 1 R) by directly targeting the T1 and T2 sites in the 3' untranslated region (3'UTR) of IGF 1R mRNA. Furthermore, they found that let-7a 1-mediated IGF I R downregulation was accompanied by attenuation of Elk1 activity and c-fos expression, inhibition of PC-3 cell proliferation, cell cycle arrest and induced apoptosis and that inhibition oflet-7al could up-regulate IGF 1R accompanied by an increase of Elk1 activity and c-fos expression,
基金financially supported by the National Key Research and Development Program of China(No.2020YFC1909604)the Natural Science Foundation of China(Nos.52202269 and 52002248)+1 种基金Shenzhen Science and Technology program(No.20220810155330003)Shenzhen Basic Research Program(No.JCYJ20190808163005631)。
文摘Reasonable design and applications of graphene-based materials are supposed to be promising ways to tackle many fundamental problems emerging in lithium batteries,including suppression of electrode/electrolyte side reactions,stabilization of electrode architecture,and improvement of conductive component.Therefore,extensive fundamental research on this aspect has been performed so far.However,when it comes to large-scale industrial applications,the utilization of graphene-based materials progresses at a very slow pace.Namely,there presents a severe technological decoupling between academic research and industrial application,and there is an urgent need to link them.Herein,in order to address current issues of graphene-based materials used in lithium batteries,we present their latest advancements with stateof-the-art technologies.Potential applications of graphenebased materials in practical lithium batteries are highlighted and predicted to bridge the gap between the academic progress and industrial manufacture,thereby paving the way for accelerating the development of graphenebased material as well as lithium battery industry.
基金supported by CITIC Dameng Mining Industries Limited-Guangxi University Joint Research Institute of Manganese Resources Utilization and Advanced Materials Technology,Guangxi University-CITIC Dameng Mining Industries Limited Joint Base of Postgraduate Cultivation,and State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structuresthe National Natural Science Foundation of China(Nos.11364003 and 52102470)+1 种基金Guangxi Innovation Driven Development Project Grant(Nos.AA17204100 and AA18118052)the Natural Science Foundation of Guangxi Province(No.2018GXNSFAA138186)。
文摘With the increasing consumption of fossil fuels,proton exchange membrane fuel cells(PEMFCs)have attracted considerable attention as green and sustainable energy conversion devices.The slow kinetics of the cathodic oxygen reduction reaction(ORR)has a major impact on the performance of PEMFCs,and although platinum(Pt)can accelerate the reaction rate of the ORR,the scarcity and high cost of Pt resources still limit the development of PEMFCs.Therefore,the development of low-cost high-performance ORR catalysts is essential for the commercial application and development of PEMFCs.This paper reviews the research progress of researchers on Pt-based ORR catalysts in recent years,including Pt/C catalysts,Pt-based alloy catalysts,Pt-based intermetallic compounds,and Pt-based single-atom catalysts(SACs),with a focus on Pt-based alloy catalysts with different nanostructures.We described in detail the difficulties and solutions in the research process of various ORR catalysts and explained the principle of their activity enhancement with density functional theory(DFT).In addition,an outlook on the development of Pt-based catalysts is given,and reducing the amount of Pt used and improving the performance of catalysts are the directions to work on in the coming period.
基金financially supported by the National Natural Science Foundation of China(Nos.51971090 and U21A20311)。
文摘Lithium-iron manganese phosphates(LiFex Mn_(1-x)PO_(4),0.1<x<0.9)have the merits of high safety and high working voltage.However,they also face the challenges of insufficient conductivity and poor cycling stability.Some progress has been achieved to solve these problems.Herein,we firstly summarized the influence of different electrolyte systems on the electrochemical performance of LiFexMn_(1-x)PO_(4),and then discussed the effect of element doping,lastly studied the influences of conductive layer coating and morphology control on the cycling stability.Finally,the prospects and challenges of developing high-cycling LiFexMn_(1-x)PO_(4) were proposed.
基金financially supported by the National Natural Science Foundation of China(Nos.51971090,U21A20311)。
文摘Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is regarded as the promising cathode for lithium-ion batteries(LIBs).However,the challenges such as safety issues and poor cycling performance have seriously hindered its commercial applications.In order to overcome these difficulties,there has been extensive research and development of electrolyte modifications for high-energy-density LIBs with Ni-rich cathodes.Herein,this review introduces the research progress based on solvent additives,salt type additives and other electrolytes for LIBs with NCM811cathode materials and discusses how they control the interface stability.In particular,some recommendations for further modification of enhancing electrolyte stability and improving NCM811 electrochemical properties are summarized and proposed,which put forward new design rules for the screening and customizing ideal electrolyte additives for high performance NCM811 cathode-based LIBs.
基金financially supported by the National Natural Science Foundation of China(No.52102470)。
文摘The large-scale application of lithium metal batteries remains a challenge due to the hydrolysis of LiPF_(6),which can induce capacity fade and series of safety issues.Prof.Ma and his co-workers have designed a hydrophobic Li^(+)-solvated structure to obtain high performances lithium metal batteries.The specific functional groups of theadditive,hexafluoroisopropyl acrylate.
基金supported by the National Natural Science Foundation of China(No.52102470)the Science and Technology Development Project of Jilin Province(No.20200501012GX)。
文摘As the most mature portable power source,lithium-ion battery has become the mainstream of power source for electric vehicles(EVs)by virtue of its high energy density,long cycle life and relatively low cost.However,an excellent battery management system remained to be a problem for the operational states monitoring and safety guarantee for EVs.In this paper,a function realization of multi-scale modeling is proposed based on cyber hierarchy and interactional network framework,realizing basic functions such as multi-scale mapping and cloud-based modeling.Furthermore,to solve the problem of limited computing capability of the conventional vehicle-end battery management system,the novel system consists of hierarchies of side,edge and cloud,which are designed to take on different computing tasks methodically and swap data iteratively,providing specific services for drivers,enterprise users,etc.Due to a series of promising features,this system has a large range of application scenarios as well as some critical bottlenecks,which will be discussed at the end of the article.Please check and confirm D.-B.Shan"is correctly identified in author group.It’s not correct.There is no"D.-B.Shan"in author group,please just remove it.