1.Introduction With the upgrading of major equipment,the mechanical prop-erty requirements for structural materials are increasingly high.The maraging steel or maraging stainless steel has long repre-sented the highes...1.Introduction With the upgrading of major equipment,the mechanical prop-erty requirements for structural materials are increasingly high.The maraging steel or maraging stainless steel has long repre-sented the highest strength alloy to be developed as reported in recent researches[1-8].The tensile strength of this kind of alloy is usually around 2.0 GPa.The yield strength of a maraging steel re-cently fabricated by laser powder bed fusion can reach as high as about 2.4 GPa,but it is unfortunate that the elongation is merely about 1%[9].So it seems that 2.0 GPa yield strength is an upper limitation for this kind of alloy.To break through this limitation,it is of significance to establish a new composition design strat-egy.For instance,recent work[10]reported a medium Mn steel doped with Al and V elements,which exhibits an ultra-high yield strength of 2.21 GPa with 15%uniform elongation after thermo-mechanical processing.In another aspect,the design using multi-ple principal elements and additional elements to form a high en-tropy alloy(HEA)should be a very promising pathway.展开更多
Anode-free Li-metal batteries are of significant interest to energy storage industries due to their intrinsically high energy.However,the accumulative Li dendrites and dead Li continuously consume active Li during cyc...Anode-free Li-metal batteries are of significant interest to energy storage industries due to their intrinsically high energy.However,the accumulative Li dendrites and dead Li continuously consume active Li during cycling.That results in a short lifetime and low Coulombic efficiency of anode-free Li-metal batteries.Introducing effective electrolyte additives can improve the Li deposition homogeneity and solid electrolyte interphase(SEI)stability for anode-free Li-metal batteries.Herein,we reveal that introducing dual additives,composed of LiAsF6 and fluoroethylene carbonate,into a low-cost commercial carbonate electrolyte will boost the cycle life and average Coulombic efficiency of NMC‖Cu anode-free Li-metal batteries.The NMC‖Cu anode-free Li-metal batteries with the dual additives exhibit a capacity retention of about 75%after 50 cycles,much higher than those with bare electrolytes(35%).The average Coulombic efficiency of the NMC‖Cu anode-free Li-metal batteries with additives can maintain 98.3%over 100 cycles.In contrast,the average Coulombic efficiency without additives rapidly decline to 97%after only 50 cycles.In situ Raman measurements reveal that the prepared dual additives facilitate denser and smoother Li morphology during Li deposition.The dual additives significantly suppress the Li dendrite growth,enabling stable SEI formation on anode and cathode surfaces.Our results provide a broad view of developing low-cost and high-effective functional electrolytes for high-energy and long-life anode-free Li-metal batteries.展开更多
In order to visualize singularity of SGCMGs in gimbal angle space,a novel continuous bounded singularity parameter--Singularity Radius,whose sign can distinctly determine singularity type,is proposed.Then a rapid sing...In order to visualize singularity of SGCMGs in gimbal angle space,a novel continuous bounded singularity parameter--Singularity Radius,whose sign can distinctly determine singularity type,is proposed.Then a rapid singularity-escape steering law is proposed basing on gradient of Singularity Radius and residual base vector to drive the SGCMG system to neighboring singular boundary,and quickly escape elliptic singularities.Finally,simulation results on Pyramid-type and skew-type configuration demonstrate the effectiveness and rapidness of the proposed steering law.展开更多
This study experimentally investigated basal texture initiation and development during cold rolling,in combination with simulation using a modified visco-plastic self-consistent(VPSC)model.The results showed that the ...This study experimentally investigated basal texture initiation and development during cold rolling,in combination with simulation using a modified visco-plastic self-consistent(VPSC)model.The results showed that the orientation of extension twins exhibit a random distribution after rolling.In contrast,the matrix grains deformed by slips tend to orientate with their c-axis around the normal direction(ND).Plastic strain concentration induced by dislocation piling up at grain boundaries contributes to plastic deformation inhomogeneity,and promotes the basal-pyramidal and prismatic-prismatic binary slips.Incorporated with the interactions between the basaland pyramidal<c+a>dislocations,and between the prismaticdislocations,the VPSC model replicates the experimental results,effectively demonstrating the process of the basal texture initiation and development.The basal texture initiation is independent of twinning,and results mainly from the development of misorientation induced by the formation of dislocation sub-boundaries via the interaction between the basaland pyramidal<c+a>dislocations.展开更多
Despite their interesting properties,nanostructured materials have found limited use as a result of the cost of preparation and the difficulty in scaling up.Herein,a two-pass friction stir processing(FSP)technique is ...Despite their interesting properties,nanostructured materials have found limited use as a result of the cost of preparation and the difficulty in scaling up.Herein,a two-pass friction stir processing(FSP)technique is employed to refine grain sizes to a nanoscale.Nanocrystalline AZ61 Mg alloy with an av-erage grain size of less than 100nm was successfully obtained using FSP.Corresponding to this,the highest microhardness of the nano-grained region reached triple times that of AZ61 substrate.In prin-ciple,by applying multiple overlapping passes,it should be possible to produce any desired size thin sheet of nanostructure using this technique.We expect that the FSP technique may pave a way to large-scale structural applications of nanostructured metals and alloys.展开更多
Posttraumatic stress disorder(PTSD)and major depressive disorder(MDD)are common stress-related psychiatric disorders.Genetic and neurobiology research has supported the viewpoint that PTSD and MDD may possess common a...Posttraumatic stress disorder(PTSD)and major depressive disorder(MDD)are common stress-related psychiatric disorders.Genetic and neurobiology research has supported the viewpoint that PTSD and MDD may possess common and disorder-specific underlying mechanisms.In this systematic review,we summarize evidence for the similarities and differences in brain functional and structural features of MDD,PTSD,and their comorbidity,as well as the effects of extensively used therapies in patients with comorbid PTSD and MDD(PTSD+MDD).These functional magnetic resonance imaging(MRI)studies highlight the(i)shared hypoactivation in the prefrontal cortex during cognitive and emotional processing in MDD and PTSD;(ii)higher activation in fear processing regions including amygdala,hippocampus,and insula in PTSD compared to MDD;and(iii)distinct functional deficits in brain regions involved in fear and reward processing in patients with PTSD+MDD relative to those with PTSD alone.These structural MRI studies suggested that PTSD and MDD share features of reduced volume in focal frontal areas.The treatment effects in patients with PTSD+MDD may correlate with the normalization trend of structural alterations.Neuroimaging predictors of repetitive transcranial magnetic stimulation response in patients with PTSD+MDD may differ from the mono-diagnostic groups.In summary,neuroimaging studies to date have provided limited information about the shared and disorder-specific features in MDD and PTSD.Further research is essential to pave the way for developing improved diagnostic markers and eventually targeted treatment approaches for the shared and distinct brain alterations presented in patients with MDD and PTSD.展开更多
基金National Natural Science Foundation of China(No.51371121).
文摘1.Introduction With the upgrading of major equipment,the mechanical prop-erty requirements for structural materials are increasingly high.The maraging steel or maraging stainless steel has long repre-sented the highest strength alloy to be developed as reported in recent researches[1-8].The tensile strength of this kind of alloy is usually around 2.0 GPa.The yield strength of a maraging steel re-cently fabricated by laser powder bed fusion can reach as high as about 2.4 GPa,but it is unfortunate that the elongation is merely about 1%[9].So it seems that 2.0 GPa yield strength is an upper limitation for this kind of alloy.To break through this limitation,it is of significance to establish a new composition design strat-egy.For instance,recent work[10]reported a medium Mn steel doped with Al and V elements,which exhibits an ultra-high yield strength of 2.21 GPa with 15%uniform elongation after thermo-mechanical processing.In another aspect,the design using multi-ple principal elements and additional elements to form a high en-tropy alloy(HEA)should be a very promising pathway.
基金fellowship support from the China Scholarship Council
文摘Anode-free Li-metal batteries are of significant interest to energy storage industries due to their intrinsically high energy.However,the accumulative Li dendrites and dead Li continuously consume active Li during cycling.That results in a short lifetime and low Coulombic efficiency of anode-free Li-metal batteries.Introducing effective electrolyte additives can improve the Li deposition homogeneity and solid electrolyte interphase(SEI)stability for anode-free Li-metal batteries.Herein,we reveal that introducing dual additives,composed of LiAsF6 and fluoroethylene carbonate,into a low-cost commercial carbonate electrolyte will boost the cycle life and average Coulombic efficiency of NMC‖Cu anode-free Li-metal batteries.The NMC‖Cu anode-free Li-metal batteries with the dual additives exhibit a capacity retention of about 75%after 50 cycles,much higher than those with bare electrolytes(35%).The average Coulombic efficiency of the NMC‖Cu anode-free Li-metal batteries with additives can maintain 98.3%over 100 cycles.In contrast,the average Coulombic efficiency without additives rapidly decline to 97%after only 50 cycles.In situ Raman measurements reveal that the prepared dual additives facilitate denser and smoother Li morphology during Li deposition.The dual additives significantly suppress the Li dendrite growth,enabling stable SEI formation on anode and cathode surfaces.Our results provide a broad view of developing low-cost and high-effective functional electrolytes for high-energy and long-life anode-free Li-metal batteries.
基金funded under the National Natural Science Foundation of China(No.61873312)。
文摘In order to visualize singularity of SGCMGs in gimbal angle space,a novel continuous bounded singularity parameter--Singularity Radius,whose sign can distinctly determine singularity type,is proposed.Then a rapid singularity-escape steering law is proposed basing on gradient of Singularity Radius and residual base vector to drive the SGCMG system to neighboring singular boundary,and quickly escape elliptic singularities.Finally,simulation results on Pyramid-type and skew-type configuration demonstrate the effectiveness and rapidness of the proposed steering law.
基金the financial support from the National Foundation of Natural Science(No.51371121) of China.
文摘This study experimentally investigated basal texture initiation and development during cold rolling,in combination with simulation using a modified visco-plastic self-consistent(VPSC)model.The results showed that the orientation of extension twins exhibit a random distribution after rolling.In contrast,the matrix grains deformed by slips tend to orientate with their c-axis around the normal direction(ND).Plastic strain concentration induced by dislocation piling up at grain boundaries contributes to plastic deformation inhomogeneity,and promotes the basal-pyramidal and prismatic-prismatic binary slips.Incorporated with the interactions between the basaland pyramidal<c+a>dislocations,and between the prismaticdislocations,the VPSC model replicates the experimental results,effectively demonstrating the process of the basal texture initiation and development.The basal texture initiation is independent of twinning,and results mainly from the development of misorientation induced by the formation of dislocation sub-boundaries via the interaction between the basaland pyramidal<c+a>dislocations.
基金Supported by the National Natural Science Foundation of China(Grant No.50771067)
文摘Despite their interesting properties,nanostructured materials have found limited use as a result of the cost of preparation and the difficulty in scaling up.Herein,a two-pass friction stir processing(FSP)technique is employed to refine grain sizes to a nanoscale.Nanocrystalline AZ61 Mg alloy with an av-erage grain size of less than 100nm was successfully obtained using FSP.Corresponding to this,the highest microhardness of the nano-grained region reached triple times that of AZ61 substrate.In prin-ciple,by applying multiple overlapping passes,it should be possible to produce any desired size thin sheet of nanostructure using this technique.We expect that the FSP technique may pave a way to large-scale structural applications of nanostructured metals and alloys.
基金supported by the National Natural Science Foundation of China(Grant Nos.82302159 and 82001795)Post-Doctor Research Project of West China Hospital of Sichuan University(2021HXBH025)Sichuan Province Science and Technology Program(2022YFS0069,2021YFS0242,and 2023YFS0076).
文摘Posttraumatic stress disorder(PTSD)and major depressive disorder(MDD)are common stress-related psychiatric disorders.Genetic and neurobiology research has supported the viewpoint that PTSD and MDD may possess common and disorder-specific underlying mechanisms.In this systematic review,we summarize evidence for the similarities and differences in brain functional and structural features of MDD,PTSD,and their comorbidity,as well as the effects of extensively used therapies in patients with comorbid PTSD and MDD(PTSD+MDD).These functional magnetic resonance imaging(MRI)studies highlight the(i)shared hypoactivation in the prefrontal cortex during cognitive and emotional processing in MDD and PTSD;(ii)higher activation in fear processing regions including amygdala,hippocampus,and insula in PTSD compared to MDD;and(iii)distinct functional deficits in brain regions involved in fear and reward processing in patients with PTSD+MDD relative to those with PTSD alone.These structural MRI studies suggested that PTSD and MDD share features of reduced volume in focal frontal areas.The treatment effects in patients with PTSD+MDD may correlate with the normalization trend of structural alterations.Neuroimaging predictors of repetitive transcranial magnetic stimulation response in patients with PTSD+MDD may differ from the mono-diagnostic groups.In summary,neuroimaging studies to date have provided limited information about the shared and disorder-specific features in MDD and PTSD.Further research is essential to pave the way for developing improved diagnostic markers and eventually targeted treatment approaches for the shared and distinct brain alterations presented in patients with MDD and PTSD.
