The high strength 7xxx series aluminium alloys are usually difficult to be prepared as semi-solid feedstock, because some dispersoid particles （soluble only in liquid） could pin at grain and subgrain boundary to mak...The high strength 7xxx series aluminium alloys are usually difficult to be prepared as semi-solid feedstock, because some dispersoid particles （soluble only in liquid） could pin at grain and subgrain boundary to make the alloy difficultly recrystallise. In this work, a novel multistep reheating regime is developed for recrystallisation and partial melting （RAP） route to prepare fine spheroidal microstructure of semi-solid AI-Zn- Mg-Cu alloy. After reheating to 665 ℃, holding for 4 min and subsequent isothermally holding at 620 ℃ with total heating time of 15 min, fine spheroidal microstructures with grain size of-40 μm were prepared without remained unrecrystallised grains and directionality, which are much finer than the conventionally obtained microstructures （-100 μm）.展开更多
The nitrogen content of tetrazolo triazines is 68.9%.In this paper,tetrazolotriazines was synthetized.The TG-DSC test indicated its decomposition process in detail.The non-isothermal kinetic parameters were speculated...The nitrogen content of tetrazolo triazines is 68.9%.In this paper,tetrazolotriazines was synthetized.The TG-DSC test indicated its decomposition process in detail.The non-isothermal kinetic parameters were speculated by Kissinger and Ozawa methods.It revealed the mechanism function of thermal decomposition.The impact and friction sensitivity were tested.The detonation pressure and velocity were calculated.It has a wide range of potential applications as a kind of energetic material.展开更多
The thermal decomposition processes of（MgCO3）4·Mg（OH）2·5H2O（MCH）,5ZnO·2CO3·4H2O（ZCH）,NiCO3·2Ni（OH）2·4H2O（NCH）,PbCO3（LC）and [Cr（OH）5]2·CO3·8H2O（CC）were studied ...The thermal decomposition processes of（MgCO3）4·Mg（OH）2·5H2O（MCH）,5ZnO·2CO3·4H2O（ZCH）,NiCO3·2Ni（OH）2·4H2O（NCH）,PbCO3（LC）and [Cr（OH）5]2·CO3·8H2O（CC）were studied via TG-DSC.The results of research imply that MCH has the largest capacity of heat absorption and ZCH is second to MCH among the studied materials.The non-isothermal kinetic parameters of MCH and ZCH were calculated by Kissinger and Ozawa methods.Furthermore,thermal decomposition mechanisms of MCH and ZCH were investigated by Coats-Redfern method.Due to the large specific heat capacity,MCH and ZCH are promising to be used as a coolant in extinguishant formulations.展开更多
A set of novel forming die combining the advantages of dies casting and forging was designed, by which double control forming idea was firstly proposed. The motorcycle wheel made of AM60B alloy was used as the typical...A set of novel forming die combining the advantages of dies casting and forging was designed, by which double control forming idea was firstly proposed. The motorcycle wheel made of AM60B alloy was used as the typical component to demonstrate advantages of the double control forming. The effect of pressure on the mechanical properties and microstructure of the parts formed by double control forming was investigated. The results showed that high mechanical properties and complex shape were achieved in the parts formed by double control forming. Compared to die casting, the mechanical properties of the formed part significantly increased and the microstructure changed from the coarse dendrites to fine equiaxed grains. The shrinkage voids and microcracks in the formed parts were obviously reduced or even completely eliminated with the increase of pressure. When a pressure of 4000 kN was applied, the optimal mechanical properties such as ultimate tensile strength of 265.6 MPa and elongation of 21% were achieved and the microstructure was characterized by fine and uniform equiaxed grains due to the large undercooling degree caused by the high pressure.展开更多
Coal pitch,an important by-product in the coal coking industry with a high output,is a low-cost and high-carbon yield precursor for the manufacturing of high-value carbon materials.Herein,N/O co-doped carbon fber(CFcp...Coal pitch,an important by-product in the coal coking industry with a high output,is a low-cost and high-carbon yield precursor for the manufacturing of high-value carbon materials.Herein,N/O co-doped carbon fber(CFcp),fabricated by electrospinning using pre-oxidized coal pitch as the precursor,was employed as the sulfur host for Li-s batteries.The presence of more pyrrolic N and graphic N in CFcp than carbon fiber made from polyacrylonitrile benefits the adsorption of lithium polysulfde and the battery's life.Sulphur-CFcp cathode(S@CFcp)exhibited excellent specific capacity and cyclability,with a specific capacity of 701.1 mAh/g and a low capacity decay rate of 0.088%per cycle over 200 cycles at 2.0 C,respectively.The high ion diffusion rate,low charge transfer resistance,and effective conversion of lithium polysulfides enable the high electrochemical performance of S@CFcp.展开更多
Ventricular hypertrophy is a powerful and independent predictor of cardiovascular morbid events. The vascular properties of low-dose acetyl salicylic acid （aspirin） provide cardiovascular benefits through the irreve...Ventricular hypertrophy is a powerful and independent predictor of cardiovascular morbid events. The vascular properties of low-dose acetyl salicylic acid （aspirin） provide cardiovascular benefits through the irreversible inhibition of platelet cyclooxygenase 1; however, the possible anti-hypertrophic properties and potential mechanism of aspirin have not been investigated in detail. In this study, healthy wild-type male mice were randomly divided into three groups and subjected to transverse aortic constriction （TAC） or sham operation. The TAC-operated mice were treated with the human equivalent of low-dose aspirin （10 mg·kg^-1· d^-1）; the remaining mice received an equal amount of phosphate buffered saline with 0.65% ethanol, which was used as a vehicle. A cardiomyocyte hypertrophy model induced by angiotensin II （10 nmol· L^-1） was treated with the human equivalent of low （10 or 100μmol·L^-1） and high （1000μmol·L^-1） aspirin concentrations in plasma. Changes in the cardiac structure and function were assessed through echocardiography and transmission electron microscopy. Gene expression was determined through RT-PCR and western blot analysis. Results indicated that aspirin treatment abrogated the increased thickness of the left ventricular anterior and posterior walls, the swelling of mitochondria, and the increased surface area in in vivo and in vitro hypertrophy models. Aspirin also normalized the upregulated hypertrophic biomarkers, p-myosin heavy chain （IS-MHC）, atrial natriuretic peptide （ANP）, and b-type natriuretic peptide （BNP）. Aspirin efficiently reversed the upregulation of β-catenin and P-Akt expression and the TAC- or ANG II-induced downregulation of GSK-3~. Therefore, low-dose aspirin possesses significant anti-hypertrophic properties at clinically relevant concentrations for anti-thrombotic therapy. The downregulation of β-catenin and Akt may be the underlying signaling mechanism of the effects of aspirin.展开更多
基金the National Natural Science Foundation of China under Grant Nos.50774026,50875059 and 51174064
文摘The high strength 7xxx series aluminium alloys are usually difficult to be prepared as semi-solid feedstock, because some dispersoid particles （soluble only in liquid） could pin at grain and subgrain boundary to make the alloy difficultly recrystallise. In this work, a novel multistep reheating regime is developed for recrystallisation and partial melting （RAP） route to prepare fine spheroidal microstructure of semi-solid AI-Zn- Mg-Cu alloy. After reheating to 665 ℃, holding for 4 min and subsequent isothermally holding at 620 ℃ with total heating time of 15 min, fine spheroidal microstructures with grain size of-40 μm were prepared without remained unrecrystallised grains and directionality, which are much finer than the conventionally obtained microstructures （-100 μm）.
基金Supported by the State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology)(YBKT16-09,QNKT16-03)
文摘The nitrogen content of tetrazolo triazines is 68.9%.In this paper,tetrazolotriazines was synthetized.The TG-DSC test indicated its decomposition process in detail.The non-isothermal kinetic parameters were speculated by Kissinger and Ozawa methods.It revealed the mechanism function of thermal decomposition.The impact and friction sensitivity were tested.The detonation pressure and velocity were calculated.It has a wide range of potential applications as a kind of energetic material.
基金Supported by the Basic Research Foundation of Beijing Institute of Technology(20130242017)the Project Foundation of State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology)(YBKT16-09)
文摘The thermal decomposition processes of（MgCO3）4·Mg（OH）2·5H2O（MCH）,5ZnO·2CO3·4H2O（ZCH）,NiCO3·2Ni（OH）2·4H2O（NCH）,PbCO3（LC）and [Cr（OH）5]2·CO3·8H2O（CC）were studied via TG-DSC.The results of research imply that MCH has the largest capacity of heat absorption and ZCH is second to MCH among the studied materials.The non-isothermal kinetic parameters of MCH and ZCH were calculated by Kissinger and Ozawa methods.Furthermore,thermal decomposition mechanisms of MCH and ZCH were investigated by Coats-Redfern method.Due to the large specific heat capacity,MCH and ZCH are promising to be used as a coolant in extinguishant formulations.
基金supported by the National Natural Science Foundation of China(NSFC) under Grant No.51075099the Natural Science Foundation of the Heilongjiang Province under the Grant No.E201038+3 种基金the China Postdoctoral Science Foundation under the Grant No.20090460884the Fundamental Research Funds for the Central Universities under the Grant No.HIT.NSRIF. 2013007the Harbin City Young Scientists Foundation under the Grant No.2011RFQXG010the Specially Postdoctoral Science Foundation of Heilongjiang Province under Grant No. LBH-T1102
文摘A set of novel forming die combining the advantages of dies casting and forging was designed, by which double control forming idea was firstly proposed. The motorcycle wheel made of AM60B alloy was used as the typical component to demonstrate advantages of the double control forming. The effect of pressure on the mechanical properties and microstructure of the parts formed by double control forming was investigated. The results showed that high mechanical properties and complex shape were achieved in the parts formed by double control forming. Compared to die casting, the mechanical properties of the formed part significantly increased and the microstructure changed from the coarse dendrites to fine equiaxed grains. The shrinkage voids and microcracks in the formed parts were obviously reduced or even completely eliminated with the increase of pressure. When a pressure of 4000 kN was applied, the optimal mechanical properties such as ultimate tensile strength of 265.6 MPa and elongation of 21% were achieved and the microstructure was characterized by fine and uniform equiaxed grains due to the large undercooling degree caused by the high pressure.
基金support from the Natural Scientific Foundation of China(22078002,22108004,and 22178002)supported also by the Anhui Provincial Department of Education key Project in Natural science for Universities(2023AH051114 and 2022AH050331).
文摘Coal pitch,an important by-product in the coal coking industry with a high output,is a low-cost and high-carbon yield precursor for the manufacturing of high-value carbon materials.Herein,N/O co-doped carbon fber(CFcp),fabricated by electrospinning using pre-oxidized coal pitch as the precursor,was employed as the sulfur host for Li-s batteries.The presence of more pyrrolic N and graphic N in CFcp than carbon fiber made from polyacrylonitrile benefits the adsorption of lithium polysulfde and the battery's life.Sulphur-CFcp cathode(S@CFcp)exhibited excellent specific capacity and cyclability,with a specific capacity of 701.1 mAh/g and a low capacity decay rate of 0.088%per cycle over 200 cycles at 2.0 C,respectively.The high ion diffusion rate,low charge transfer resistance,and effective conversion of lithium polysulfides enable the high electrochemical performance of S@CFcp.
基金Acknowledgements This work was supported by the Funds for Creative Research Groups （No. 81421063） and the Major Program of the National Natural Science Foundation of China （Nos. 81130088, 81230081, and 31450OO9）.
文摘Ventricular hypertrophy is a powerful and independent predictor of cardiovascular morbid events. The vascular properties of low-dose acetyl salicylic acid （aspirin） provide cardiovascular benefits through the irreversible inhibition of platelet cyclooxygenase 1; however, the possible anti-hypertrophic properties and potential mechanism of aspirin have not been investigated in detail. In this study, healthy wild-type male mice were randomly divided into three groups and subjected to transverse aortic constriction （TAC） or sham operation. The TAC-operated mice were treated with the human equivalent of low-dose aspirin （10 mg·kg^-1· d^-1）; the remaining mice received an equal amount of phosphate buffered saline with 0.65% ethanol, which was used as a vehicle. A cardiomyocyte hypertrophy model induced by angiotensin II （10 nmol· L^-1） was treated with the human equivalent of low （10 or 100μmol·L^-1） and high （1000μmol·L^-1） aspirin concentrations in plasma. Changes in the cardiac structure and function were assessed through echocardiography and transmission electron microscopy. Gene expression was determined through RT-PCR and western blot analysis. Results indicated that aspirin treatment abrogated the increased thickness of the left ventricular anterior and posterior walls, the swelling of mitochondria, and the increased surface area in in vivo and in vitro hypertrophy models. Aspirin also normalized the upregulated hypertrophic biomarkers, p-myosin heavy chain （IS-MHC）, atrial natriuretic peptide （ANP）, and b-type natriuretic peptide （BNP）. Aspirin efficiently reversed the upregulation of β-catenin and P-Akt expression and the TAC- or ANG II-induced downregulation of GSK-3~. Therefore, low-dose aspirin possesses significant anti-hypertrophic properties at clinically relevant concentrations for anti-thrombotic therapy. The downregulation of β-catenin and Akt may be the underlying signaling mechanism of the effects of aspirin.
