Stegolophodon is an age-informative genus of mammals that had a widespread distribution during the Neogene.This paper reports the discovery of Stegolophodon fossils from the Middle Miocene lower Fotan Formation at the...Stegolophodon is an age-informative genus of mammals that had a widespread distribution during the Neogene.This paper reports the discovery of Stegolophodon fossils from the Middle Miocene lower Fotan Formation at the Zhangpu locality,Fujian Province,China.This discovery represents the first evidence of Neogene proboscidean fossils in southeastern China.The newly found molar materials have low tooth crowns,very straight lophs/lophids,and an indistinct median sulcus.The mesoconelets and posterior cingulum are well-developed,while the second posterior pretrite central conule is significantly reduced.These specimens closely resemble Stegolophodon pseudolatidens in cheek tooth morphology,and can thus be attributed to the same species.This discovery fills a gap in the fossil record of large mammals in this region during the Neogene and provides valuable insights into the evolution of proboscideans and paleoenvironments.展开更多
The preferential oxidation of CO(CO-PROX)reaction is a cost-effective method for eliminating trace amounts of CO from the fuel H2.Pt-based catalysts have been extensively studied for COPROX,with their activity influen...The preferential oxidation of CO(CO-PROX)reaction is a cost-effective method for eliminating trace amounts of CO from the fuel H2.Pt-based catalysts have been extensively studied for COPROX,with their activity influenced by the morphology of the support.Hydrothermal synthesis was employed to produce different morphologies ofγ-Al_(2)O_(3):flower-likeγ-Al_(2)O_(3)(f)exposing(110)crystal faces,sheet-likeγ-Al_(2)O_(3)(s)revealing(100)crystal faces,and rod-likeγ-Al_(2)O_(3)(r)displaying(111)crystal faces,followed by loading PtCo nanoparticles.The exposed crystal faces of the support impact the alloying degree of the PtCo nanoparticles,and an increase in the alloying degree correlates with enhanced catalyst reactivity.Pt_(3)Co intermetallic compounds were identified onγ-Al_(2)O_(3)(f)exposing(110)crystal faces,and PtCo/γ-Al_(2)O_(3)(f)showed high catalytic activity in the CO-PROX reaction,achieving 100%CO conversion across a broad temperature range of 50−225°C.In contrast,only partial alloying of PtCo was observed onγ-Al_(2)O_(3)(s).Furthermore,no alloying between Pt and Co occurred in PtCo/γ-Al_(2)O_(3)(r),resulting in a reaction rate at 50°C that was merely 11%of that of PtCo/γ-Al_(2)O_(3)(f).The formation of Pt3Co intermetallic compounds led to a more oxidized state of Pt,which significantly diminished the adsorption of CO on Pt and augmented the active oxygen species,thereby facilitating the selective oxidation of CO.展开更多
Porous spherical MnCo_(2)S_(4) was synthesized by a simple solvothermal method.Thanks to the well-designedbimetallic composition and the unique porous spherical structure,the MnCo_(2)S_(4) electrode exhibited an excep...Porous spherical MnCo_(2)S_(4) was synthesized by a simple solvothermal method.Thanks to the well-designedbimetallic composition and the unique porous spherical structure,the MnCo_(2)S_(4) electrode exhibited an exceptionalspecific capacitance of 190.8 mAh·g^(-1)at 1 A·g^(-1),greatly higher than the corresponding monometallic sulfides MnS(31.7 mAh·g^(-1))and Co_(3)S_(4)(86.7 mAh·g^(-1)).Impressively,the as-assembled MnCo_(2)S_(4)||porous carbon(PC)hybridsupercapacitor(HSC),showed an outstanding energy density of 76.88 Wh·kg^(-1)at a power density of 374.5 W·kg^(-1),remarkable cyclic performance with a capacity retention of 86.8% after 10000 charge-discharge cycles at 5 A·g^(-1),and excellent Coulombic efficiency of 99.7%.展开更多
The genus Uzelina Melichar,1903 is recorded for the first time in China with a new species,Uzelina(Uzelina)pterygoida sp.nov.,described and illustrated.A key to species in the Oriental region and a checklist with dist...The genus Uzelina Melichar,1903 is recorded for the first time in China with a new species,Uzelina(Uzelina)pterygoida sp.nov.,described and illustrated.A key to species in the Oriental region and a checklist with distribution of members of the genus Uzelina are provided.展开更多
The influence of geometric configuration on the friction characteristics during incremental sheet forming of AA5052 was analyzed by integrating surface morphology and its characteristic parameters,along with plastic s...The influence of geometric configuration on the friction characteristics during incremental sheet forming of AA5052 was analyzed by integrating surface morphology and its characteristic parameters,along with plastic strain,contact pressure,and area.The interface promotes lubrication and support when wall angles were≤40°,a 0.5 mm-thin sheet was used,and a 10 mm-large tool radius was employed.This mainly results in micro-plowing and plastic extrusion flow,leading to lower friction coefficient.However,when wall angles exceed 40°,significant plastic strain roughening occurs,leading to inadequate lubrication on the newly formed surface.Increased sheet thickness and decreased tool radius elevate contact pressure.These actions trigger micro-cutting and adhesion,potentially leading to localized scuffing and dimple tears,and higher friction coefficient.The friction mechanisms remain unaffected by the part’s plane curve features.As the forming process progresses,abrasive wear intensifies,and surface morphology evolves unfavorably for lubrication and friction reduction.展开更多
The known species in the genus Clemelis Robineau-Desvoidy,1863 from China are reviewed and one new species from Shanxi,C.xuei sp.nov.,is described and illustrated.Clemelis jingentaoi,Zhang&Hao,2019 is a synonym of...The known species in the genus Clemelis Robineau-Desvoidy,1863 from China are reviewed and one new species from Shanxi,C.xuei sp.nov.,is described and illustrated.Clemelis jingentaoi,Zhang&Hao,2019 is a synonym of Austrophorocera hirsute(Mesnil,1946),syn.nov.A key to the two Chinese species is provided.展开更多
During the automated placement process of dry fibers,the positioning and fixation of dry fiber gauze belts are achieved by spraying setting agents.The amount of the setting agent is difficult to control when it is spr...During the automated placement process of dry fibers,the positioning and fixation of dry fiber gauze belts are achieved by spraying setting agents.The amount of the setting agent is difficult to control when it is sprayed manually.Furthermore,it can also affect the permeability of the preform,resin injection and the quality of the vacuum assisted resin infusion(VARI)molding,resulting in a decrease in the mechanical properties of composite materials.This study utilizes dry fiber automated placement equipment and an automated spraying system to manufacture preform structures,followed by VARI process to prepare composite samples with varying setting agent contents.Subsequently,mechanical characterization including interlaminar shear,bending and tensile testing is conducted to investigate the influence of setting agent content on both the manufacturing process and the mechanical properties of composite products.The results show that the interlaminar shear strength,bending strength and tensile strength of the sample gradually decrease with the increase of the content of the setting agent.The optimal setting agent content for automated laying of dry fiber is determined to be 4%-6%,balancing the preformed body’s layup quality and its impact on mechanical properties.Compared with agent-free samples,this range results in reductions of 3% in interlaminar shear strength,9% in bending strength,11% in bending modulus,and 13%-16% in tensile strength.展开更多
To guarantee the computational accuracy of the finite element model,the strain-compensated Arrhenius-type model,modified Fields-Backofen(m-FB)model and modified Zerilli-Armstrong(m-ZA)model were established to predict...To guarantee the computational accuracy of the finite element model,the strain-compensated Arrhenius-type model,modified Fields-Backofen(m-FB)model and modified Zerilli-Armstrong(m-ZA)model were established to predict the hightemperature flow stress of as-cast low alloyed Al-0.5Cu,Al-1Si,and Al-1Si-0.5Cu.To determine the material constants of these three constitutive models,isothermal compression tests of the three aluminum alloys were carried out on a Gleeble-3800 thermal simulator.The prediction results of the constitutive model were compared with the experimental results to evaluate the prediction accuracy of the constitutive models,and to provide a basis for selecting the most suitable constitutive models(parameters)for the three alloys mentioned above.It is found that the strain-compensated Arrhenius model and m-ZA model can be regarded as the most suitable constitutive models for Al-0.5Cu and Al-1Si alloys,respectively,and these two constitutive models also can be applied to Al-1Si-0.5Cu alloy.However,the m-FB model can be applied to Al-0.5Cu,Al-1Si and Al-1Si-0.5Cu alloys only under high temperature and medium strain conditions.展开更多
文摘Stegolophodon is an age-informative genus of mammals that had a widespread distribution during the Neogene.This paper reports the discovery of Stegolophodon fossils from the Middle Miocene lower Fotan Formation at the Zhangpu locality,Fujian Province,China.This discovery represents the first evidence of Neogene proboscidean fossils in southeastern China.The newly found molar materials have low tooth crowns,very straight lophs/lophids,and an indistinct median sulcus.The mesoconelets and posterior cingulum are well-developed,while the second posterior pretrite central conule is significantly reduced.These specimens closely resemble Stegolophodon pseudolatidens in cheek tooth morphology,and can thus be attributed to the same species.This discovery fills a gap in the fossil record of large mammals in this region during the Neogene and provides valuable insights into the evolution of proboscideans and paleoenvironments.
基金supported by the National Natural Science Foundation of China(22376063,21976057)the Fund of the National Engineering Laboratory for Mobile Source Emission Control Technology(NELMS2020A05)Fundamental Research Funds for the Central Universities.
文摘The preferential oxidation of CO(CO-PROX)reaction is a cost-effective method for eliminating trace amounts of CO from the fuel H2.Pt-based catalysts have been extensively studied for COPROX,with their activity influenced by the morphology of the support.Hydrothermal synthesis was employed to produce different morphologies ofγ-Al_(2)O_(3):flower-likeγ-Al_(2)O_(3)(f)exposing(110)crystal faces,sheet-likeγ-Al_(2)O_(3)(s)revealing(100)crystal faces,and rod-likeγ-Al_(2)O_(3)(r)displaying(111)crystal faces,followed by loading PtCo nanoparticles.The exposed crystal faces of the support impact the alloying degree of the PtCo nanoparticles,and an increase in the alloying degree correlates with enhanced catalyst reactivity.Pt_(3)Co intermetallic compounds were identified onγ-Al_(2)O_(3)(f)exposing(110)crystal faces,and PtCo/γ-Al_(2)O_(3)(f)showed high catalytic activity in the CO-PROX reaction,achieving 100%CO conversion across a broad temperature range of 50−225°C.In contrast,only partial alloying of PtCo was observed onγ-Al_(2)O_(3)(s).Furthermore,no alloying between Pt and Co occurred in PtCo/γ-Al_(2)O_(3)(r),resulting in a reaction rate at 50°C that was merely 11%of that of PtCo/γ-Al_(2)O_(3)(f).The formation of Pt3Co intermetallic compounds led to a more oxidized state of Pt,which significantly diminished the adsorption of CO on Pt and augmented the active oxygen species,thereby facilitating the selective oxidation of CO.
文摘Porous spherical MnCo_(2)S_(4) was synthesized by a simple solvothermal method.Thanks to the well-designedbimetallic composition and the unique porous spherical structure,the MnCo_(2)S_(4) electrode exhibited an exceptionalspecific capacitance of 190.8 mAh·g^(-1)at 1 A·g^(-1),greatly higher than the corresponding monometallic sulfides MnS(31.7 mAh·g^(-1))and Co_(3)S_(4)(86.7 mAh·g^(-1)).Impressively,the as-assembled MnCo_(2)S_(4)||porous carbon(PC)hybridsupercapacitor(HSC),showed an outstanding energy density of 76.88 Wh·kg^(-1)at a power density of 374.5 W·kg^(-1),remarkable cyclic performance with a capacity retention of 86.8% after 10000 charge-discharge cycles at 5 A·g^(-1),and excellent Coulombic efficiency of 99.7%.
基金supported by the National Natural Science Foundation of China(3175000232170472)and the National Animal Collection Resource Center,China.
文摘The genus Uzelina Melichar,1903 is recorded for the first time in China with a new species,Uzelina(Uzelina)pterygoida sp.nov.,described and illustrated.A key to species in the Oriental region and a checklist with distribution of members of the genus Uzelina are provided.
基金the support of the Key Research and Development Program of Shaanxi Province,China(No.2021GXLH-Z-049)。
文摘The influence of geometric configuration on the friction characteristics during incremental sheet forming of AA5052 was analyzed by integrating surface morphology and its characteristic parameters,along with plastic strain,contact pressure,and area.The interface promotes lubrication and support when wall angles were≤40°,a 0.5 mm-thin sheet was used,and a 10 mm-large tool radius was employed.This mainly results in micro-plowing and plastic extrusion flow,leading to lower friction coefficient.However,when wall angles exceed 40°,significant plastic strain roughening occurs,leading to inadequate lubrication on the newly formed surface.Increased sheet thickness and decreased tool radius elevate contact pressure.These actions trigger micro-cutting and adhesion,potentially leading to localized scuffing and dimple tears,and higher friction coefficient.The friction mechanisms remain unaffected by the part’s plane curve features.As the forming process progresses,abrasive wear intensifies,and surface morphology evolves unfavorably for lubrication and friction reduction.
基金supported by the Science&Technology Fundamental Resources Investigation Program(2023FY100302)the National Natural Science Foundation of China(32470459+1 种基金31272279)the Natural Science Foundation of Liaoning Province(2022-BS-332).
文摘The known species in the genus Clemelis Robineau-Desvoidy,1863 from China are reviewed and one new species from Shanxi,C.xuei sp.nov.,is described and illustrated.Clemelis jingentaoi,Zhang&Hao,2019 is a synonym of Austrophorocera hirsute(Mesnil,1946),syn.nov.A key to the two Chinese species is provided.
基金supported by the National Natural Science Foundation of China(32470477)supported by the Ministry of Culture of the Czech Republic(DRKVO 2024-2028/5.IK.a,National Museum,00023272).
文摘One new species,Pocadius spiralis sp.nov.,is described and illustrated from Sichuan,China.
基金supported by Jiangsu Provincial Key Research and Development Program(No.BE2023014-4).
文摘During the automated placement process of dry fibers,the positioning and fixation of dry fiber gauze belts are achieved by spraying setting agents.The amount of the setting agent is difficult to control when it is sprayed manually.Furthermore,it can also affect the permeability of the preform,resin injection and the quality of the vacuum assisted resin infusion(VARI)molding,resulting in a decrease in the mechanical properties of composite materials.This study utilizes dry fiber automated placement equipment and an automated spraying system to manufacture preform structures,followed by VARI process to prepare composite samples with varying setting agent contents.Subsequently,mechanical characterization including interlaminar shear,bending and tensile testing is conducted to investigate the influence of setting agent content on both the manufacturing process and the mechanical properties of composite products.The results show that the interlaminar shear strength,bending strength and tensile strength of the sample gradually decrease with the increase of the content of the setting agent.The optimal setting agent content for automated laying of dry fiber is determined to be 4%-6%,balancing the preformed body’s layup quality and its impact on mechanical properties.Compared with agent-free samples,this range results in reductions of 3% in interlaminar shear strength,9% in bending strength,11% in bending modulus,and 13%-16% in tensile strength.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region of China“Study on constitutive behavior of Al-xSi-yCu high purity aluminum alloy billets for target materials”(2020D01C023).
文摘To guarantee the computational accuracy of the finite element model,the strain-compensated Arrhenius-type model,modified Fields-Backofen(m-FB)model and modified Zerilli-Armstrong(m-ZA)model were established to predict the hightemperature flow stress of as-cast low alloyed Al-0.5Cu,Al-1Si,and Al-1Si-0.5Cu.To determine the material constants of these three constitutive models,isothermal compression tests of the three aluminum alloys were carried out on a Gleeble-3800 thermal simulator.The prediction results of the constitutive model were compared with the experimental results to evaluate the prediction accuracy of the constitutive models,and to provide a basis for selecting the most suitable constitutive models(parameters)for the three alloys mentioned above.It is found that the strain-compensated Arrhenius model and m-ZA model can be regarded as the most suitable constitutive models for Al-0.5Cu and Al-1Si alloys,respectively,and these two constitutive models also can be applied to Al-1Si-0.5Cu alloy.However,the m-FB model can be applied to Al-0.5Cu,Al-1Si and Al-1Si-0.5Cu alloys only under high temperature and medium strain conditions.
