This study was aimed at identifying underlying strengthening mechanisms and predicting the yield strength of as-extruded Mg-Zn-Y alloys with varying amounts of yttrium （Y） element. The addition of Y resulted in the ...This study was aimed at identifying underlying strengthening mechanisms and predicting the yield strength of as-extruded Mg-Zn-Y alloys with varying amounts of yttrium （Y） element. The addition of Y resulted in the formation of ternary 1 （Mg3YZn6）, W （Mg3Y2Zn3） and LPSO （Mg12YZn） phases which subse- quently reinforced alloys ZM31 ＋ 0.3Y, ZM31 ＋ 3.2Y and ZM31 ＋ 6Y, where the value denoted the amount of Y element （in wt%）. Yield strength of the alloys was determined via uniaxial compression testing, and grain size and second-phase particles were characterized using OM and SEM. In-situ high-temperature XRD was performed to determine the coefficient of thermal expansion （CTE）, which was derived to be 1.38 x 10^-5 K^-1 and 2.35 x 10^-5 K^-1 for W and LPSO phases, respectively. The individual strengthening effects in each material were quantified for the first time, including grain refinement, Orowan looping, thermal mismatch, dislocation density, load-bearing, and particle shearing contributions. Grain refinement was one of the major strengthening mechanisms and it was present in all the alloys studied, irrespective of the second-phase particles. Orowan looping and crE mismatch were the predominant strengthening mechanisms in the ZM31＋0.3Y and ZM31 ＋ 3.2Y alloys containing I and W phases, respectively, while load-bearing and second-phase shearing were the salient mechanisms contributing largely to the superior yield strength of the LPSO-reinforced ZM31 ＋ 6Y alloy.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.展开更多
The particles of Mg-Zn-Gd icosahedral quasicrystal master alloy were added into the AZ31 alloy by the repeated plastic working(RPW)process in order to improve the mechanical properties of the AZ31 alloy at room temper...The particles of Mg-Zn-Gd icosahedral quasicrystal master alloy were added into the AZ31 alloy by the repeated plastic working(RPW)process in order to improve the mechanical properties of the AZ31 alloy at room temperature.The microstructure and tensile properties of composites were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and tensile testing machine at room temperature.The results suggest that the RPW process can effectively refine the matrix and make the I-phase particles distribute uniformly.The ultimate tensile strength and the yield strength of the composites reach their maximum values of 362.3 and 330.5 MPa,respectively,when the amount of I-phase particles added is10 %.Meanwhile,the elongation of the composites decreases sharply.展开更多
Objective： This phase I study was to evaluate safety, maximum tolerated dose, pharmacokinetics and preliminary antitumor activity of chidamide, a novel subtype-selective histone deacetylase （HDAC） inhibitor, in com...Objective： This phase I study was to evaluate safety, maximum tolerated dose, pharmacokinetics and preliminary antitumor activity of chidamide, a novel subtype-selective histone deacetylase （HDAC） inhibitor, in combination with paclitaxel and carboplatin in patients with advanced non-small cell lung cancer （NSCLC）. Methods： Ten patients received oral chidamide 20, 25, or 30 mg twice per week continuously with paclitaxel （175 mg/m2） and carboplatin [area under the curve （AUC） 5 mg/mL/min] administered in a 3-week cycle. Patients with response and stable disease after four cycles maintained chidamide monotherapy until disease progression or unacceptable toxicity. Blood samples were collected for pharmacoldnetic analysis after the first single oral of chidamide and first combination treatment in cycle 1 from all patients. Results： Two dose-limiting toxicities were recorded in the 30 mg cohort, including thrombocytopenia and prolonged neutropenia in the first cycle. Grade 3/4 neutropenia in any cycle was observed in all patients, but was not associated with significant complications. Other grade 3/4 hematologic toxicities included thrombocytopenia and leucopenia. No significant changes were observed in pharmacokinetic parameters for both chidamide and paclitaxel. One patient in the 20 mg cohort had confirmed partial response （PR）. Two out of 5 patients with brain metastases had intracranial complete remission after 4-cycle treatment. Conclusions： Chidamide combined with paclitaxel and carboplatin was generally tolerated without unanticipated toxicities or clinically relevant pharmacokinetic interactions. The recommended dose for chidamide in this combination was established at 20 mg, and a phase II trial is ongoing with this regimen in patients with advanced NSCLC.展开更多
The infiuence of small calcium additions on the high-temperature mechanical behaviour in an extruded Mg-6Zn-l Y(wt.%)alloy reinforced by the I-phase has been investigated.Calcium promotes the formation of the intermet...The infiuence of small calcium additions on the high-temperature mechanical behaviour in an extruded Mg-6Zn-l Y(wt.%)alloy reinforced by the I-phase has been investigated.Calcium promotes the formation of the intermetallic Mg6Zn3Ca2 phase instead of 1-phase,which results in a noticeable improvement of the yield strength and ultimate tensile strength of the alloy above 100℃.The strength of the alloys was analysed taking into account the contribution due to the grain size,the crystallographic texture and the volume fraction and nature of second phase particles.In situ synchrotron radiation diffraction experiments have been used to evaluate the load partitioning between the magnesium matrix and the second phase particles(1-and MgeZgCa?phases)in both alloys.The load transfer from the magnesium matrix towards the MgeZihCa?phase is markedly more effective than that for the I-phase over the entire temperature range,especially at 200°C,temperature at which the reinforcement effect of the I-phase is null.展开更多
The use of neoadjuvant therapies has played a major role for borderline resectable and locally advanced pancreatic cancers(PCs). For this group of patients, preoperative chemotherapy or chemoradiation has increased th...The use of neoadjuvant therapies has played a major role for borderline resectable and locally advanced pancreatic cancers(PCs). For this group of patients, preoperative chemotherapy or chemoradiation has increased the likelihood of surgery with negative resection margins and overall survival. On the other hand, for patients with resectable PC, the main rationale for neoadjuvant therapy is that the overall survival with current strategies is unsatisfactory. There is a consensus that we need new treatments to improve the overall survival and quality of life of patients with PC. However, without strong scientific evidence supporting the theoretical advantages of neoadjuvant therapies, these potential benefits might turn out not to be worth the risk of tumors progression while waiting for surgery. The focus of this paper is to provide the readers an overview of the most recent evidence on this subject.展开更多
Through investigating and comparing microstructure and crystallographic texture of as-extruded Mg-14Li and Mg-14Li-6Zn-1Y(in wt%)alloys,the differences in their mechanical anisotropy were investigated.It revealed that...Through investigating and comparing microstructure and crystallographic texture of as-extruded Mg-14Li and Mg-14Li-6Zn-1Y(in wt%)alloys,the differences in their mechanical anisotropy were investigated.It revealed that the formation of I-phase(Mg3Zn6Y,icosahedral structure)can effectively refine grain size.Moreover,compared with Mg-14Li alloy,the texture type of Mg-14Li-6Zn-1Y alloy changed slightly,but its texture intensity decreased remarkably.As a result,the stronger texture contributed to the"normal"mechanical anisotropy of Mg-14Li alloy with higher tensile strength and a lower elongation ratio along transverse direction(TD)than those along extrusion direction(ED).However,for Mg-14Li-6Zn-1Y alloy,the zonal distribution of I-phase particles along ED caused"abnormal"mechanical anisotropy,i.e.higher tensile strength and better plasticity along ED.展开更多
Microstructures and mechanical properties of LZ83?xY alloys containingI-phase andW-phase were investigated by XRD, OM, SEM and EDS. The experimental results show that the content ofI-phase andW-phase changes by varyin...Microstructures and mechanical properties of LZ83?xY alloys containingI-phase andW-phase were investigated by XRD, OM, SEM and EDS. The experimental results show that the content ofI-phase andW-phase changes by varying Zn/Y mass ratio in the LZ83?xY alloys. The cohesion ofI-phase/α-Mg eutectic pockets can enhance the strength in the as-cast LZ83?0.5Y and LZ83?1.0Y alloys, while theW-phase has no obvious strengthening effect on the LZ83?1.5Y alloy. In the extruded alloys, the I-phase andW-phase were extruded into the particles with nanoscale size in theβ-Li matrix phase. The dispersion strengthening of W-phase was more obvious because of the higher volume fraction. The ultimate tensile strength of extruded LZ83?1.5Y alloy is up to 238 MPa while the elongation is up to 20%.展开更多
Through exploring the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys in a 0.1 M NaCl solution,it revealed that the SCC susceptibility index(I_(SCC))of the Mg-8%Li alloy wa...Through exploring the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys in a 0.1 M NaCl solution,it revealed that the SCC susceptibility index(I_(SCC))of the Mg-8%Li alloy was 47%,whilst the I_(SCC)of the Mg-8%Li-6%Zn-1.2%Y alloy was 68%.Surface,cross-sectional and fractography observations indicated that for the Mg-8%Li alloy,theα-Mg/β-Li interfaces acted as the preferential crack initiation sites and propagation paths during the SCC process.With regard to the Mg-8%Li-6%Zn-1.2%Y alloy,the crack initiation sites included the I-phase and the interfaces of I-phase/β-Li andα-Mg/β-Li,and the preferential propagation paths were the I-phase/β-Li andα-Mg/β-Li interfaces.Moreover,the SCC of the two alloys was concerned with hydrogen embrittlement(HE)mechanism.展开更多
Microstructural evolution and age-hardening behavior of Mg-2 Dy-6 Zn(at%)alloy during solid-solution and aging treatment were investigated.The microstructure of as-cast alloy is composed of a-Mg,Mg3 DyZn6(Ⅰ)phase,Mg3...Microstructural evolution and age-hardening behavior of Mg-2 Dy-6 Zn(at%)alloy during solid-solution and aging treatment were investigated.The microstructure of as-cast alloy is composed of a-Mg,Mg3 DyZn6(Ⅰ)phase,Mg3 Dy2 Zn3(W)phase,Mg(Zn,Dy)phase and a small amount of Mg0.97Zn0.03 phases.After solid-solution treatment(480℃,12 h),all the I phases and most W phases dissolve into a-Mg matrix and the remainder W phases transform into Mg(Dy,Zn)phase and MgDy3 phase.During aging treatment,I phase and small amounts of W phases co-precipitate from α-Mg matrix,respectively.The alloy exhibits a peak hardness of HV 77.5 at 200 ℃ for 8 h.The excellent age-hardening behavior of alloy is mainly attributed to the co-precipitation strengthening of I and W phases.展开更多
The microstructure and mechanical performance of the unidirectionally and cross-directionally rolled Mg-8Li-6Zn-1Y(in wt.%)sheets have been investigated and compared.It reveals that after the unidirectional rolling(UR...The microstructure and mechanical performance of the unidirectionally and cross-directionally rolled Mg-8Li-6Zn-1Y(in wt.%)sheets have been investigated and compared.It reveals that after the unidirectional rolling(UR),the broken I-phase particles are aggregated at theα-Mg/β-Li phase interfaces.However,the cross-rolling(CR)process can not only severely break the bulk I-phase,but also cause the obviously uniform distribution of I-phase particles in the matrix phases.Moreover,the average grain size of the CR samples is 3.61μm and about 50%that of the UR samples.The maximum texture intensities ofα-Mg andβ-Li phases in the CR samples are slightly stronger than those in the UR samples.Tensile results demonstrate that the CR process can effectively enhance the tensile properties and remarkably reduce the mechanical anisotropy of the alloy.For the UR samples,the yield strength,ultimate tensile strength,and elongation ratio along the rolling direction(RD)are 164 MPa,198 MPa,and 16.4%,whereas those along the transverse direction(TD)are 157 MPa,185 MPa,and 22.0%,respectively.For the CR samples,their mechanical properties are basically the same and the mechanical anisotropy is almost eliminated.The yield strength,ultimate tensile strength,and elongation ratio along the cross-rolling direction 1(CRD1)and 2(CRD2)are respectively measured to be 181 MPa and 182 MPa,220 MPa and 218 MPa,20.6%and 20.7%.Failure analysis indicates that for the UR samples being tensile tested along the RD and TD,microcracks are preferentially initiated in the region of aggregated I-phase particles.For the CR samples being tensile tested along both two cross-rolling directions,the initiation of micro-cracks mainly occurs at the I-phase/matrix phase interfaces and in the interior of matrix phases.展开更多
Huwentoxin-I, a neurotoxic peptide from the spider Selenocosmia huwena, was synthesized by sol-id-phase method with Fluorenylmethoxycarbonyl amino acid pentafluorophenyl esters (Fmoc-AA-OPfp). The carboxyl and the hyd...Huwentoxin-I, a neurotoxic peptide from the spider Selenocosmia huwena, was synthesized by sol-id-phase method with Fluorenylmethoxycarbonyl amino acid pentafluorophenyl esters (Fmoc-AA-OPfp). The carboxyl and the hydroxy groups were protected by tBu; the side chains of Lys and His were protected by Roc; the guanidine group of Arg was protected by Mtr and the mercaptan group of Cys was protected by Trt. The solid-phase carrier was ethylene diamine-polyethylene-polystyrene (DEA-PEG-PS) resin. The synthetic peptide was cleaved from the resin and deprotected by a 90% TFA solution containing 5% thioanisole, 3% ethanedithiol and 2% anisole. The product was reduced with DTT and then incubated with GSSG and GSH to form the correct disulfide bond linkages. The syn-thetic peptide was purified by HPLC and then characterized by amino acid composition and sequence analysis, peptide mapping and NMR. The biological activity of the synthetic product was tested by electrophysiological method using the isolated mouse phrenic nerve diaphragm preparation. The results indicated that the synthetic huwentoxin-I has the same chemical and conformational structure and biological activity as those of the native huwentoxin-I from the spider.展开更多
基金the Natural Sciences and Engineering Research Council of Canada (NSERC)Ontario Trillium Scholarships (OTS) program for providing financial support+8 种基金financial support by the Premier’s Research Excellence Award (PREA)Canada Foundation for Innovation (CFI)Ryerson Research Chair (RRC) programthe Ministry of Science and Technology of China (2014DFG52810)National Great Theoretic Research Project of China (2013CB632200)National Natural Science Foundation of China (Project 51474043)Ministry of Education of China (SRFDR 20130191110018)Chongqing Municipal Government(CSTC2013JCYJC60001)Chongqing Science and Technology Commission (CSTC2011gjhz50001)
文摘This study was aimed at identifying underlying strengthening mechanisms and predicting the yield strength of as-extruded Mg-Zn-Y alloys with varying amounts of yttrium （Y） element. The addition of Y resulted in the formation of ternary 1 （Mg3YZn6）, W （Mg3Y2Zn3） and LPSO （Mg12YZn） phases which subse- quently reinforced alloys ZM31 ＋ 0.3Y, ZM31 ＋ 3.2Y and ZM31 ＋ 6Y, where the value denoted the amount of Y element （in wt%）. Yield strength of the alloys was determined via uniaxial compression testing, and grain size and second-phase particles were characterized using OM and SEM. In-situ high-temperature XRD was performed to determine the coefficient of thermal expansion （CTE）, which was derived to be 1.38 x 10^-5 K^-1 and 2.35 x 10^-5 K^-1 for W and LPSO phases, respectively. The individual strengthening effects in each material were quantified for the first time, including grain refinement, Orowan looping, thermal mismatch, dislocation density, load-bearing, and particle shearing contributions. Grain refinement was one of the major strengthening mechanisms and it was present in all the alloys studied, irrespective of the second-phase particles. Orowan looping and crE mismatch were the predominant strengthening mechanisms in the ZM31＋0.3Y and ZM31 ＋ 3.2Y alloys containing I and W phases, respectively, while load-bearing and second-phase shearing were the salient mechanisms contributing largely to the superior yield strength of the LPSO-reinforced ZM31 ＋ 6Y alloy.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.
基金financially supported by Beijing Municipal Science and Technology Commission(No.Z131100003213019)National Natural Science Foundation of China(Nos.51101002 and 51301006)Beijing Municipal Commission of Education(Nos.KM201310005001 and KM201110005001)
文摘The particles of Mg-Zn-Gd icosahedral quasicrystal master alloy were added into the AZ31 alloy by the repeated plastic working(RPW)process in order to improve the mechanical properties of the AZ31 alloy at room temperature.The microstructure and tensile properties of composites were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and tensile testing machine at room temperature.The results suggest that the RPW process can effectively refine the matrix and make the I-phase particles distribute uniformly.The ultimate tensile strength and the yield strength of the composites reach their maximum values of 362.3 and 330.5 MPa,respectively,when the amount of I-phase particles added is10 %.Meanwhile,the elongation of the composites decreases sharply.
基金supported in part by grants from Chinese National Major Project for New Drug Innovation(2012ZX09303012-001)
文摘Objective： This phase I study was to evaluate safety, maximum tolerated dose, pharmacokinetics and preliminary antitumor activity of chidamide, a novel subtype-selective histone deacetylase （HDAC） inhibitor, in combination with paclitaxel and carboplatin in patients with advanced non-small cell lung cancer （NSCLC）. Methods： Ten patients received oral chidamide 20, 25, or 30 mg twice per week continuously with paclitaxel （175 mg/m2） and carboplatin [area under the curve （AUC） 5 mg/mL/min] administered in a 3-week cycle. Patients with response and stable disease after four cycles maintained chidamide monotherapy until disease progression or unacceptable toxicity. Blood samples were collected for pharmacoldnetic analysis after the first single oral of chidamide and first combination treatment in cycle 1 from all patients. Results： Two dose-limiting toxicities were recorded in the 30 mg cohort, including thrombocytopenia and prolonged neutropenia in the first cycle. Grade 3/4 neutropenia in any cycle was observed in all patients, but was not associated with significant complications. Other grade 3/4 hematologic toxicities included thrombocytopenia and leucopenia. No significant changes were observed in pharmacokinetic parameters for both chidamide and paclitaxel. One patient in the 20 mg cohort had confirmed partial response （PR）. Two out of 5 patients with brain metastases had intracranial complete remission after 4-cycle treatment. Conclusions： Chidamide combined with paclitaxel and carboplatin was generally tolerated without unanticipated toxicities or clinically relevant pharmacokinetic interactions. The recommended dose for chidamide in this combination was established at 20 mg, and a phase II trial is ongoing with this regimen in patients with advanced NSCLC.
基金The authors would like to acknowledge financial support of the Spanish Ministry of Science and Innovation under project number MAT2016-78850-RWe would like to acknowledge the expert support of A.Garcia,A.Tomas and M.Maier for assistance with SEM.The Deutches Elektronen-Synchrotron DESY is acknowledged for the provision of beamtime at the P07 beamline of the PETRA III synchrotron facility in the framework of proposal I-20170054EC.
文摘The infiuence of small calcium additions on the high-temperature mechanical behaviour in an extruded Mg-6Zn-l Y(wt.%)alloy reinforced by the I-phase has been investigated.Calcium promotes the formation of the intermetallic Mg6Zn3Ca2 phase instead of 1-phase,which results in a noticeable improvement of the yield strength and ultimate tensile strength of the alloy above 100℃.The strength of the alloys was analysed taking into account the contribution due to the grain size,the crystallographic texture and the volume fraction and nature of second phase particles.In situ synchrotron radiation diffraction experiments have been used to evaluate the load partitioning between the magnesium matrix and the second phase particles(1-and MgeZgCa?phases)in both alloys.The load transfer from the magnesium matrix towards the MgeZihCa?phase is markedly more effective than that for the I-phase over the entire temperature range,especially at 200°C,temperature at which the reinforcement effect of the I-phase is null.
基金Stefanie Condon-Oldreive founder and director of Craig’s Cause Pancreatic Cancer Society (www.craigscause.ca) for the research scholarship that supported Dr. Sheikh Hasibur Raman while working on this project
文摘The use of neoadjuvant therapies has played a major role for borderline resectable and locally advanced pancreatic cancers(PCs). For this group of patients, preoperative chemotherapy or chemoradiation has increased the likelihood of surgery with negative resection margins and overall survival. On the other hand, for patients with resectable PC, the main rationale for neoadjuvant therapy is that the overall survival with current strategies is unsatisfactory. There is a consensus that we need new treatments to improve the overall survival and quality of life of patients with PC. However, without strong scientific evidence supporting the theoretical advantages of neoadjuvant therapies, these potential benefits might turn out not to be worth the risk of tumors progression while waiting for surgery. The focus of this paper is to provide the readers an overview of the most recent evidence on this subject.
基金supported financially by the Strategic New Industry Development Special Foundation of Shenzhen (No. JCYJ20170306141749970)the National Natural Science Foundation of China (Nos.51871211 and 51701129)+3 种基金the Natural Science Foundation of Guangdong Province (No.2018A030313950)the funds of International Joint Laboratory for Light Alloys,the National Key Research and Development Program of China (Nos. 2017YFB0702001 and 2016YFB0301105)Liaoning BaiQianWan Talents Programthe Innovation Fund of Institute of Metal Research (IMR),Chinese Academy of Sciences (CAS)
文摘Through investigating and comparing microstructure and crystallographic texture of as-extruded Mg-14Li and Mg-14Li-6Zn-1Y(in wt%)alloys,the differences in their mechanical anisotropy were investigated.It revealed that the formation of I-phase(Mg3Zn6Y,icosahedral structure)can effectively refine grain size.Moreover,compared with Mg-14Li alloy,the texture type of Mg-14Li-6Zn-1Y alloy changed slightly,but its texture intensity decreased remarkably.As a result,the stronger texture contributed to the"normal"mechanical anisotropy of Mg-14Li alloy with higher tensile strength and a lower elongation ratio along transverse direction(TD)than those along extrusion direction(ED).However,for Mg-14Li-6Zn-1Y alloy,the zonal distribution of I-phase particles along ED caused"abnormal"mechanical anisotropy,i.e.higher tensile strength and better plasticity along ED.
基金Project(2007CB613702)supported by the National Basic Research Program of ChinaProject(CDJZR14130007)supported by the Fundamental Research Funds for the Central Universities,China
文摘Microstructures and mechanical properties of LZ83?xY alloys containingI-phase andW-phase were investigated by XRD, OM, SEM and EDS. The experimental results show that the content ofI-phase andW-phase changes by varying Zn/Y mass ratio in the LZ83?xY alloys. The cohesion ofI-phase/α-Mg eutectic pockets can enhance the strength in the as-cast LZ83?0.5Y and LZ83?1.0Y alloys, while theW-phase has no obvious strengthening effect on the LZ83?1.5Y alloy. In the extruded alloys, the I-phase andW-phase were extruded into the particles with nanoscale size in theβ-Li matrix phase. The dispersion strengthening of W-phase was more obvious because of the higher volume fraction. The ultimate tensile strength of extruded LZ83?1.5Y alloy is up to 238 MPa while the elongation is up to 20%.
基金the National Natural Science Foundation of China Projects under Grant[Nos.51871211,U21A2049,52071220,51701129 and 51971054]Liaoning Province’s project of"Revitalizing Liaoning Talents"(XLYC1907062)+10 种基金the Doctor Startup Fund of Natural Science Foundation Program of Liaoning Province(No.2019-BS-200)the Strategic New Industry Development Special Foundation of Shenzhen(JCYJ20170306141749970)the funds of International Joint Laboratory for Light AlloysLiaoning Bai Qian Wan Talents Programthe Domain Foundation of Equipment Advance Research of 13th Five-year Plan(61409220118)National Key Research and Development Program of China under Grant[Nos.2017YFB0702001 and 2016YFB0301105]the Innovation Fund of Institute of Metal Research(IMR)Chinese Academy of Sciences(CAS)the National Basic Research Program of China(973 Program)project under Grant No.2013CB632205the Fundamental Research Fund for the Central Universities under Grant[No.N2009006]Bintech-IMR R&D Program[No.GYY-JSBU-2022-009]。
文摘Through exploring the stress corrosion cracking(SCC)behaviors of the as-cast Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys in a 0.1 M NaCl solution,it revealed that the SCC susceptibility index(I_(SCC))of the Mg-8%Li alloy was 47%,whilst the I_(SCC)of the Mg-8%Li-6%Zn-1.2%Y alloy was 68%.Surface,cross-sectional and fractography observations indicated that for the Mg-8%Li alloy,theα-Mg/β-Li interfaces acted as the preferential crack initiation sites and propagation paths during the SCC process.With regard to the Mg-8%Li-6%Zn-1.2%Y alloy,the crack initiation sites included the I-phase and the interfaces of I-phase/β-Li andα-Mg/β-Li,and the preferential propagation paths were the I-phase/β-Li andα-Mg/β-Li interfaces.Moreover,the SCC of the two alloys was concerned with hydrogen embrittlement(HE)mechanism.
基金financially supported by the National Natural Science Foundation of China(Nos.51301082 and51464031)
文摘Microstructural evolution and age-hardening behavior of Mg-2 Dy-6 Zn(at%)alloy during solid-solution and aging treatment were investigated.The microstructure of as-cast alloy is composed of a-Mg,Mg3 DyZn6(Ⅰ)phase,Mg3 Dy2 Zn3(W)phase,Mg(Zn,Dy)phase and a small amount of Mg0.97Zn0.03 phases.After solid-solution treatment(480℃,12 h),all the I phases and most W phases dissolve into a-Mg matrix and the remainder W phases transform into Mg(Dy,Zn)phase and MgDy3 phase.During aging treatment,I phase and small amounts of W phases co-precipitate from α-Mg matrix,respectively.The alloy exhibits a peak hardness of HV 77.5 at 200 ℃ for 8 h.The excellent age-hardening behavior of alloy is mainly attributed to the co-precipitation strengthening of I and W phases.
基金supported by the National Natural Science Foundation of China Projects under Grant(Nos.52071220,U21A2049,51871211,51701129,and 51971054)China Postdoctoral Science Foundation(No.2023M733572)+7 种基金Liaoning Province’s project of“Revitalizing Liaoning Talents”(No.XLYC1907062)the Doctor Startup Fund of Natural Science Foundation Program of Liaoning Province(No.2019-BS-200)High level achievement construction project of Shenyang Ligong University(No.SYLUXM202105)Liaoning BaiQianWan Talents Program,the Domain Foundation of Equipment Advance Research of 13th Five-year Plan(No.61409220118)National Key Research and Development Program of China under Grant(Nos.2017YFB0702001 and 2016YFB0301105)the Innovation Fund of Institute of Metal Research(IMR),Chinese Academy of Sciences(CAS),the National Basic Research Program of China(973 Program)project under Grant No.2013CB632205the Fundamental Research Fund for the Central Universities under Grant(No.N2009006)Bintech-IMR R&D Program(No.GYY-JSBU-2022–009).
文摘The microstructure and mechanical performance of the unidirectionally and cross-directionally rolled Mg-8Li-6Zn-1Y(in wt.%)sheets have been investigated and compared.It reveals that after the unidirectional rolling(UR),the broken I-phase particles are aggregated at theα-Mg/β-Li phase interfaces.However,the cross-rolling(CR)process can not only severely break the bulk I-phase,but also cause the obviously uniform distribution of I-phase particles in the matrix phases.Moreover,the average grain size of the CR samples is 3.61μm and about 50%that of the UR samples.The maximum texture intensities ofα-Mg andβ-Li phases in the CR samples are slightly stronger than those in the UR samples.Tensile results demonstrate that the CR process can effectively enhance the tensile properties and remarkably reduce the mechanical anisotropy of the alloy.For the UR samples,the yield strength,ultimate tensile strength,and elongation ratio along the rolling direction(RD)are 164 MPa,198 MPa,and 16.4%,whereas those along the transverse direction(TD)are 157 MPa,185 MPa,and 22.0%,respectively.For the CR samples,their mechanical properties are basically the same and the mechanical anisotropy is almost eliminated.The yield strength,ultimate tensile strength,and elongation ratio along the cross-rolling direction 1(CRD1)and 2(CRD2)are respectively measured to be 181 MPa and 182 MPa,220 MPa and 218 MPa,20.6%and 20.7%.Failure analysis indicates that for the UR samples being tensile tested along the RD and TD,microcracks are preferentially initiated in the region of aggregated I-phase particles.For the CR samples being tensile tested along both two cross-rolling directions,the initiation of micro-cracks mainly occurs at the I-phase/matrix phase interfaces and in the interior of matrix phases.
基金Project supported by the National Natural Science Foundation of China and Hunan Educational Committee.
文摘Huwentoxin-I, a neurotoxic peptide from the spider Selenocosmia huwena, was synthesized by sol-id-phase method with Fluorenylmethoxycarbonyl amino acid pentafluorophenyl esters (Fmoc-AA-OPfp). The carboxyl and the hydroxy groups were protected by tBu; the side chains of Lys and His were protected by Roc; the guanidine group of Arg was protected by Mtr and the mercaptan group of Cys was protected by Trt. The solid-phase carrier was ethylene diamine-polyethylene-polystyrene (DEA-PEG-PS) resin. The synthetic peptide was cleaved from the resin and deprotected by a 90% TFA solution containing 5% thioanisole, 3% ethanedithiol and 2% anisole. The product was reduced with DTT and then incubated with GSSG and GSH to form the correct disulfide bond linkages. The syn-thetic peptide was purified by HPLC and then characterized by amino acid composition and sequence analysis, peptide mapping and NMR. The biological activity of the synthetic product was tested by electrophysiological method using the isolated mouse phrenic nerve diaphragm preparation. The results indicated that the synthetic huwentoxin-I has the same chemical and conformational structure and biological activity as those of the native huwentoxin-I from the spider.
