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Ultrafine ordered L1_(2)-Pt-Co-Mn ternary intermetallic nanoparticles as high-performance oxygen-reduction electrocatalysts for practical fuel cells
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作者 Enping Wang Liuxuan Luo +12 位作者 Yong Feng Aiming Wu Huiyuan Li Xiashuang Luo Yangge Guo Zehao Tan Fengjuan Zhu Xiaohui Yan Qi Kang Zechao Zhuang Daihui Yang Shuiyun Shen Junliang Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第6期157-165,I0005,共10页
The long-range periodically ordered atomic structures in intermetallic nanoparticles(INPs)can significantly enhance both the electrocatalytic activity and electrochemical stability toward the oxygen reduction reaction... The long-range periodically ordered atomic structures in intermetallic nanoparticles(INPs)can significantly enhance both the electrocatalytic activity and electrochemical stability toward the oxygen reduction reaction(ORR)compared to the disordered atomic structures in ordinary solid-solution alloy NPs.Accordingly,through a facile and scalable synthetic method,a series of carbon-supported ultrafine Pt_3Co_(x)Mn_(1-x)ternary INPs are prepared in this work,which possess the"skin-like"ultrathin Pt shells,the ordered L1_(2) atomic structure,and the high-even dispersion on supports(L1_(2)-Pt_3Co_(x)Mn_(1-x)/~SPt INPs/C).Electrochemical results present that the composition-optimized L1_(2)-Pt_3Co_(0.7)Mn_(0.3)/~SPt INPs/C exhibits the highest electrocata lytic activity among the series,which are also much better than those of the pristine ultrafine Pt/C.Besides,it also has a greatly enhanced electrochemical stability.In addition,the effects of annealing temperature and time are further investigated.More importantly,such superior ORR electrocatalytic performance of L1_(2)-Pt_3Co_(0.7)Mn_(0.3)/~SPt INPs/C are also well demonstrated in practical fuel cells.Physicochemical characterization analyses further reveal the major origins of the greatly enhanced ORR electrocata lytic performance:the Pt-Co-Mn alloy-induced geometric and ligand effects as well as the extremely high L1_(2) atomic-ordering degree.This work not only successfully develops a highly active and stable ordered ternary intermetallic ORR electrocatalyst,but also elucidates the corresponding"structure-function"relationship,which can be further applied in designing other intermetallic(electro)catalysts. 展开更多
关键词 Platinum Cobalt Manganese Oxygen reduction reaction Ordered intermetallic l1_(2)atomic structure Proton-exchange membrane fuel cell
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Al-Cr-Fe-Mn-Ni高熵合金中的L2_(1)相的相稳定性及其性能研究
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作者 易慧 吴长军 +3 位作者 周琛 刘亚 陆晓旺 苏旭平 《材料导报》 EI CAS CSCD 北大核心 2024年第11期196-204,共9页
为开发兼具良好强度与塑性的BCC基高熵合金,可引入与基体共格的B2或L2_(1)相。L2_(1)相具有更好的抗蠕变性能,有望在高温环境中得到应用。但是,目前对BCC型高熵合金中L2_(1)相的存在规律、相稳定性及其对合金性能的影响还缺乏深入的研... 为开发兼具良好强度与塑性的BCC基高熵合金,可引入与基体共格的B2或L2_(1)相。L2_(1)相具有更好的抗蠕变性能,有望在高温环境中得到应用。但是,目前对BCC型高熵合金中L2_(1)相的存在规律、相稳定性及其对合金性能的影响还缺乏深入的研究。为此,本工作研究了电弧熔炼制备的铸态Al_(0.5)Cr_(2.5-x)FeMn_(x)Ni(x=0.5~1.75)、Al_(0.75)Cr_(2.25-y)FeMn_(y)Ni(y=0.25~1.5)、AlCr_(2-z)FeMn_(z)Ni(z=0.5~1.5)高熵合金的相组成,及800℃或1000℃真空退火120 h对合金组织和相组成的影响。研究表明,这些合金中L2_(1)相的成分特征由40%~50%(原子分数)Ni和15%~20%(原子分数)Al、Mn组成。L2_(1)相只存在于Al含量为10%~15%(原子分数)的合金中,且多以BCC+L2_(1)两相共存,获得的组织为编织网状的调幅分解组织。当Al含量达到20%(原子分数)后,合金则由BCC+B2两相构成。L2_(1)相的存在会使BCC型XRD特征峰出现明显的峰分裂。经过800℃或1000℃退火后,合金中L2_(1)相仍能稳定存在,合金显微组织发生粗化并会形成σ或FCC相。铸态合金的硬度随Mn含量的增加而降低,含L2_(1)相的合金的硬度在463HV~558HV范围内。800℃退火会使含5%~15%(原子分数)Mn的合金硬度降低70HV~100HV,但由于硬质σ相的析出,含20%~30%(原子分数)Mn的合金硬度提高200HV以上;1000℃退火后,由于软质FCC相的形成,合金的硬度略有降低,这些结果将为BCC型高熵合金的设计奠定基础。 展开更多
关键词 Al-Cr-Fe-Mn-Ni 高熵合金 L2_(1)相 硬度 相稳定性
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L1_(2)-γ′相共格析出强化Cu_(y)(Ni_(3/4)Al_(1/4))_(100-y)合金显微组织与性能研究
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作者 薛汪洋 刘桐 +1 位作者 胡小刚 利助民 《铜业工程》 CAS 2023年第5期70-78,共9页
纳米球状L1_(2)-γ′相(Pm~-3m,a=0.3572 nm)的共格析出强化Cu-Ni-Al合金兼具优异的力学性能及一定的导电性能,被广泛应用于轨道交通、海洋运输等领域。目前缺乏纳米球状L1_(2)-γ′相共格析出的Cu-Ni-Al显微组织演变及性能关联的系统... 纳米球状L1_(2)-γ′相(Pm~-3m,a=0.3572 nm)的共格析出强化Cu-Ni-Al合金兼具优异的力学性能及一定的导电性能,被广泛应用于轨道交通、海洋运输等领域。目前缺乏纳米球状L1_(2)-γ′相共格析出的Cu-Ni-Al显微组织演变及性能关联的系统研究。本文锁定Ni∶Al原子比3∶1,制备了系列Cu_(y)(Ni_(3/4)Al_(1/4))_(100-y) (y=75.00,80.00,85.71,90.00,93.75;原子分数)合金,并详细探讨了合金性能(硬度、电导率及软化温度)、合金成分及显微组织之间的关联。结果表明,低温时效后样品出现大量的退火孪晶并析出纳米球状L1_(2)-γ′相。低温时效后Cu-Ni-Al合金的强化机制包括细晶强化和析出强化,随着Cu含量增加(Ni+Al含量减少),退火孪晶含量减少且L1_(2)-γ′相的析出含量逐渐增加,合金硬度、屈服强度及极限抗拉强度也随之降低。而合金导电性能与固溶在Cu基体中的溶质含量相关。最后,通过软化温度测试衡量了合金在高温下的应用潜力。本研究为高性能Cu-Ni-Al合金成分设计提供了有效的实验及理论依据。 展开更多
关键词 Cu-Ni-Al合金 l1_(2)-γ′相 力学性能 软化温度 电导率
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血清hs-CRP、sCD40L、β_(2)GP1、ACA与急性脑梗死病情严重程度及预后的相关性
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作者 冉学兵 《贵州医药》 CAS 2024年第9期1359-1365,共7页
目的分析血清hs-CRP、sCD40L、β_(2)GP1、ACA与ACI患者病情严重程度及预后的相关性。方法采取回顾性研究,选择2021年6月至2023年6月医院收治的130例ACI患者临床资料作为研究对象。患者均接受阿替普酶静脉溶栓治疗,根据美国国立卫生研... 目的分析血清hs-CRP、sCD40L、β_(2)GP1、ACA与ACI患者病情严重程度及预后的相关性。方法采取回顾性研究,选择2021年6月至2023年6月医院收治的130例ACI患者临床资料作为研究对象。患者均接受阿替普酶静脉溶栓治疗,根据美国国立卫生研究院卒中量表评分(NIHSS)评估患者病情严重程度,将评分<16分患者临床资料纳入轻中组,将评分≥16分患者临床资料纳入重度组;治疗2周后,参照改良Rankin量表评分(mRS)评估患者预后,将评分<3分患者临床资料纳入预后良好组,将评分≥3分患者临床资料纳入预后不良组;统计患者基线资料,采用双变量相关性Pearson(N)分析,ACI患者血清hs-CRP、sCD40L、β_(2)GP1、ACA水平与认知功能的相关;采用二元Logistic回归分析血清hs-CRP、sCD40L、β_(2)GP1、ACA与急性脑梗死病情严重程度及预后的相关性;采用接受者操作特性曲线(ROC)分析血清hs-CRP、sCD40L、β_(2)GP1、ACA水平对ACI患者预后不良的预测价值。结果治疗后,ACI患者Fib、D-D低于治疗前(P<0.05);治疗后,ACI患者hs-CRP、sCD40L、β_(2)GP1、ACA低于治疗前(P<0.05);ACI患者治疗前的MoCA评分分低于治疗后(P<0.001);Pearson(N)分析结果显示,ACI患者血清hs-CRP、sCD40L、β_(2)GP1、ACA水平与MoCA评分呈负相关(r<0,P<0.05);重度组TOAST分型为心源性栓塞患者占比高于轻中度组,Fib、D-D、hs-CRP、sCD40L、β_(2)GP1、ACA水平高于轻中度组(P<0.05);二元Logistic回归分析结果显示,TOAST分型为心源性栓塞、其他原因/不明原因,血清Fib、D-D、hs-CRP、sCD40L、β_(2)GP1、ACA高表达是ACI患者病情为重度的危险因素(OR>1,P<0.05);预后不良组TOAST分型为心源性栓塞患者占比高于预后良好组,发病至溶栓时间长于预后良好组,Fib、D-D、hs-CRP、sCD40L、β_(2)GP1、ACA水平高于预后良好组(P<0.05);二元Logistic回归分析结果显示,TOAST分型为心源性栓塞,发病至溶栓时间长、血清Fib、D-D、hs-CRP、sCD40L、β_(2)GP1、ACA高表达是ACI患者预后不良的危险因素(OR>1,P<0.05);绘制ROC曲线结果显示,血清hs-CRP、sCD40L、β_(2)GP1、ACA水平及联合检测ACI患者预后不良的ACU均>0.70,有一定预测价值,其中联合检测最高。结论TOAST分型、血清Fib、D-D、hs-CRP、sCD40L、β_(2)GP1、ACA水平与ACI患者病情严重程度相关,同时在此基础上发病至溶栓时间与ACI患者预后关系密切。 展开更多
关键词 急性脑梗死 超敏C反应蛋白 可溶性CD40L β_(2)-糖蛋白1 抗心磷脂抗体 病情 预后
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PHASE DIAGRAM OF PrCl_3-SrCl_2-CaCl_2 SYSTEM
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作者 ZHENG Chaogui BAO Chenglin QIAO Zhiyu YE Yupu Peking University,Beijing,China 1 University of Science and Technology Beijing,Beijing,China Associate Professor,Department of Chemistry,Peking University,Beijing 100871,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1993年第7期46-51,共6页
Five fields corresponding to the primary crystallization of PrCl_3,Sr_3PrCl_9,α(SrCl_2, CaCl_2),α_1(CaCl_2,SrCl_2)and α_2(SrCl_2,CaCl_2)respectively,six univariant lines related to the secondary crystallization,one... Five fields corresponding to the primary crystallization of PrCl_3,Sr_3PrCl_9,α(SrCl_2, CaCl_2),α_1(CaCl_2,SrCl_2)and α_2(SrCl_2,CaCl_2)respectively,six univariant lines related to the secondary crystallization,one ternary eutectic(48.0 wt-% PrCl_3,23.5 wt-% SrCl_2; 590℃)and ternary peritectic point(45.5 wt-% PrCl_3,24.5 wt-% SrCl_2;614℃) were determined by DTA.Attempts were also made to explore the rule governing the alteration in the phase diagram containing rare earth chloride,formation of compound and its stability by means of polarization and counter-polarization. 展开更多
关键词 PrCl_3 PrCl-3-SrC1_2-CaCl_2 phase diagram rule of pihase diagram
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MAGNETIC PHASE DIAGRAM OF SmMn_2(Ge_(1-x)Si_x)_2 SYSTEM
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作者 Y.G. Wang F.M Yang +1 位作者 C.P. Chen, N Tang and Q.D. Wang (State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603,Beijing 100080, China)(Department of Materials Science and Engineering, Zheiang University Hangzhou 3 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1997年第1期61-64,共4页
The magnetic phase diagram (x,T) of the SmMn2(Ge1-xSix)2 system has been studied by susceptibility and magnetization measurement. With increasing silicon concentration the temperature region of ferromagnetic ordering ... The magnetic phase diagram (x,T) of the SmMn2(Ge1-xSix)2 system has been studied by susceptibility and magnetization measurement. With increasing silicon concentration the temperature region of ferromagnetic ordering decreases on the phaae diagram. 展开更多
关键词 magnetic phase diagram susceptibility and magnetization measurement X-ray diffraction SmMn_2(Ge_(1-x)Si_x)_2 system
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L1_(2)型Al_(67)Cu_(8)Ti_(25)细化剂的制备及其对铝合金组织的影响
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作者 陈旭 席卫国 +3 位作者 陈吉 程婧璠 蔡启舟 蒋文明 《特种铸造及有色合金》 CAS 北大核心 2024年第7期940-946,共7页
采用单质粉末通过高能球磨和真空烧结制备了L1_(2)型Al_(67)Cu_(8)Ti_(25)金属间化合物,并将其破碎后与Al粉进行混合制备了Al-25Al_(67)Cu_(8)Ti_(25)复合细化剂。研究了球磨时间、烧结温度对制备L1_(2)型Al_(67)Cu_(8)Ti_(25)金属间化... 采用单质粉末通过高能球磨和真空烧结制备了L1_(2)型Al_(67)Cu_(8)Ti_(25)金属间化合物,并将其破碎后与Al粉进行混合制备了Al-25Al_(67)Cu_(8)Ti_(25)复合细化剂。研究了球磨时间、烧结温度对制备L1_(2)型Al_(67)Cu_(8)Ti_(25)金属间化合物的影响。以纯铝和Al-5Cu-Mn铸造铝合金为对象,研究了复合细化剂对α-Al宏观和微观组织的影响及作用机制。结果表明,球磨粉末在600℃下烧结可制备单相的L1_(2)型Al_(67)Cu_(8)Ti_(25)化合物颗粒,随着球磨时间增加,烧结形成的化合物颗粒的平均尺寸减小至11μm,形貌趋于球形。Al-25Al_(67)Cu_(8)Ti_(25)复合细化剂对α-Al具有较好的细化效果,加入0.25%的Al_(67)Cu_(8)Ti_(25)细化剂后,纯铝及Al-5Cu-Mn合金的晶粒尺寸分别细化至224μm和137μm。L1_(2)型Al_(67)Cu_(8)Ti_(25)化合物是α-Al的有效形核质点,与α-Al的错配度为2.35%,相比于Al3Ti,其错配度更小,异质形核能力更强。 展开更多
关键词 l1_(2)型Al_(67)Cu_(8)Ti_(25)金属间化合物 显微组织 晶粒细化 异质形核
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Al_(67)Mn_8Ti_(25)合金的解理裂纹 被引量:2
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作者 文九巴 戎咏华 +1 位作者 陈世朴 胡赓祥 《中国有色金属学报》 EI CAS CSCD 北大核心 1999年第3期488-492,共5页
利用Stroh 位错塞积模型解释了L12 结构Al67 Mn8Ti25 合金室温解理裂纹的萌生。计算表明,位错塞积优先在与滑移面成35 .3°方向诱发微裂纹, 导致解理断裂。经室温弯曲断口解理面取向的电子背散射衍射(E... 利用Stroh 位错塞积模型解释了L12 结构Al67 Mn8Ti25 合金室温解理裂纹的萌生。计算表明,位错塞积优先在与滑移面成35 .3°方向诱发微裂纹, 导致解理断裂。经室温弯曲断口解理面取向的电子背散射衍射(EBSD) 测试结果验证表明,L12 结构Al67 Mn8Ti25 合金室温解理断裂裂纹优先在{110} 展开更多
关键词 l1_2结构Al_3Ti 解理断裂 电子背散射
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Machine Learning-Based Comprehensive Prediction Model for L12 Phase-Strengthened Fe-Co-Ni-Based High-Entropy Alloys
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作者 Xin Li Chenglei Wang +9 位作者 Laichang Zhang Shengfeng Zhou Jian Huang Mengyao Gao Chong Liu Mei Huang Yatao Zhu Hu Chen Jingya Zhang Zhujiang Tan 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2024年第11期1858-1874,共17页
L1_(2)phase-strengthened Fe-Co-Ni-based high-entropy alloys(HEAs)have attracted considerable attention due to their excellent mechanical properties.Improving the properties of HEAs through conventional experimental me... L1_(2)phase-strengthened Fe-Co-Ni-based high-entropy alloys(HEAs)have attracted considerable attention due to their excellent mechanical properties.Improving the properties of HEAs through conventional experimental methods is costly.Therefore,a new method is needed to predict the properties of alloys quickly and accurately.In this study,a comprehensive prediction model for L1_(2)phase-strengthened Fe-Co-Ni-based HEAs was developed.The existence of the L1_(2)phase in the HEAs was first predicted.A link was then established between the microstructure(L1_(2)phase volume fraction)and properties(hardness)of HEAs,and comprehensive prediction was performed.Finally,two mutually exclusive properties(strength and plasticity)of HEAs were coupled and co-optimized.The Shapley additive explained algorithm was also used to interpret the contribution of each model feature to the comprehensive properties of HEAs.The vast compositional and process search space of HEAs was progressively screened in three stages by applying different prediction models.Finally,four HEAs were screened from hundreds of thousands of possible candidate groups,and the prediction results were verified by experiments.In this work,L1_(2)phase-strengthened Fe-Co-Ni-based HEAs with high strength and plasticity were successfully designed.The new method presented herein has a great cost advantage over traditional experimental methods.It is also expected to be applied in the design of HEAs with various excellent properties or to explore the potential factors affecting the microstructure/properties of alloys. 展开更多
关键词 High-entropy alloy Machine learning l1_(2)phase Comprehensive prediction Shapley additive explanation(SHAP)
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Simultaneous enhancement of strength and ductility via microband formation and nanotwinning in an L1_(2)-strengthened alloy
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作者 Lu Yang Dingshan Liang +5 位作者 Zhuo Cheng Ranxi Duan Chuanxin Zhong Junhua Luan Zengbao Jiao Fuzeng Ren 《Fundamental Research》 CAS CSCD 2024年第1期147-157,共11页
Metallic alloys with high strength and large ductility are required for extreme structural applications.However,the achievement of ultrahigh strength often results in a substantially decreased ductility.Here,we report... Metallic alloys with high strength and large ductility are required for extreme structural applications.However,the achievement of ultrahigh strength often results in a substantially decreased ductility.Here,we report a strategy to achieve the strength-ductility synergy by tailoring the alloy composition to control the local stacking fault energy(SFE)of the face-centered-cubic(fcc)matrix in an L1_(2)-strengthened superlattice alloy.As a proof of concept,based on the thermodynamic calculations,we developed a non-equiatomic CoCrNi_(2)(Al_(0.2)Nb_(0.2))alloy using phase separation to create a near-equiatomic low SFE disordered CoCrNi medium-entropy alloy matrix with in situ formed high-content coherent Ni_(3)(Al,Nb)-type ordered nanoprecipitates(∼12 nm).The alloy achieves a high tensile strength up to 1.6 GPa and a uniform ductility of 33%.The low SFE of the fcc matrix promotes the formation of nanotwins and parallel microbands during plastic deformation which could remarkably enhance the strain hardening capacity.This work provides a strategy for developing ultrahigh-strength alloys with large uniform ductility. 展开更多
关键词 l1_(2)-strengthened superlattice alloy Stacking fault energy NANOTWINS MICROBANDS Strain hardening
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1,2-二苯基乙二胺及与脱氢乙酸缩合生成的席夫碱化合物对映体的高效液相色谱法拆分 被引量:1
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作者 张磊 谢宝竹 阮源萍 《色谱》 CAS CSCD 北大核心 2006年第5期531-532,共2页
关键词 高效液相色谱法(HPLC) 对映体分离(enantioseparation) l 2-二苯基乙二胺(1 2-diphenylethylenediamine) 手性固定相(chiral stationary phase)
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合金原子对L1_(2)型Al-Zr-X三元铝合金表面电偶腐蚀影响的第一性原理研究
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作者 张庆洲 范大伟 刘凌虹 《计算物理》 CSCD 北大核心 2023年第6期699-711,共13页
本文在AlZr二元合金的基础上,利用第一性原理计算方法,全面计算19种L1_(2)-Al_(x)Zr_(y)X_(z)(X=Pd、Pt、Au、K、Rb、Sr、Ba、Ca、Yb、La、Ce、Y、Er、Sc、Zr、Ti、Cd、Hf、In)三元析出相的(100)、(110)和(111)三种晶面作为表面时的功函... 本文在AlZr二元合金的基础上,利用第一性原理计算方法,全面计算19种L1_(2)-Al_(x)Zr_(y)X_(z)(X=Pd、Pt、Au、K、Rb、Sr、Ba、Ca、Yb、La、Ce、Y、Er、Sc、Zr、Ti、Cd、Hf、In)三元析出相的(100)、(110)和(111)三种晶面作为表面时的功函数,并分析其与掺杂原子电负性之间的关系,从电子层面阐明掺杂原子对L1_(2)型Al-Zr-X三元铝合金表面电偶腐蚀性能影响的根本原因。通过计算发现不同掺杂晶面暴露为表面时,由于功函数各异,与基体的本征电位差也各不相同。Hg、Cd、Zr、Ti和Hf等掺杂原子能增加析出相(100)表面的功函数,Hg、Cd、In、Ti和Hf等原子能增加析出相(110)面的功函数,而Pd、Pt、Au、In、Sc、Rb、Sr、Yb、Y、Er、K、Ba、La、Ce和Ca原子能降低(111)面的功函数,这些均导致析出相与铝基体的本征电位差进一步减小。此外,结果揭示了掺杂原子电负性与其化合物功函数之间的线性正相关规律。相较而言,电负性与Al接近且替代Al的In、Cd和Hg原子,以及电负性与Zr接近且替代Zr的Ti和Hf原子对析出相功函数影响较小,且其化合物与铝基体的电势差较小,对提升材料抗腐蚀能力有益,其他掺杂原子则对析出相功函数有较大影响。研究解释了部分耐蚀性实验结果,为优化合金成分设计、提升铝合金材料耐腐蚀性提供了理论参考。 展开更多
关键词 电偶腐蚀 铝合金 l1_(2)析出相 合金原子 第一性原理计算
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Mechanical properties of defective L1_(2)-Al_(3)X(X=Sc,Lu)phase:A first-principles study 被引量:2
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作者 Yu Wang Ya'nan Meng +2 位作者 Junsheng Wang Chi Zhang Houbing Huang 《Journal of Rare Earths》 SCIE EI CAS CSCD 2021年第2期217-224,共8页
The mechanical properties of Al_(3)X(X=Sc,Lu)were studied by density functional theory(DFT).The elastic constants and formation enthalpy indicate that the L1_(2)-Al_(3)X(X=Sc and Lu)are mechanically and thermodynamica... The mechanical properties of Al_(3)X(X=Sc,Lu)were studied by density functional theory(DFT).The elastic constants and formation enthalpy indicate that the L1_(2)-Al_(3)X(X=Sc and Lu)are mechanically and thermodynamically stable.The bulk moduli and shear moduli show that Al_(3)Sc has better resistance to volume and shape changes than AI3 Lu.However,the calculated results show that Al_(3)Lu has better plasticity than Al_(3)Sc.The properties of structural stability and elastic moduli of the crystal containing four major types of point defects in L1_(2)-Al_(3)X(X=Sc and Lu)were calculated.The mechanical properties of point defects show that point defects cause L1_(2)-Al_(3)X lattice distortion and change the corresponding elastic constants.Point defects reduce the Young’s,shear and bulk moduli but have little effects on the crystal brittleness and toughness of Al_(3)Sc and Al_(3)Lu.Therefore,we have found that Lu addition into aluminum alloys is a very good replacement for expensive Sc addition when the L1_(2)structures are desired for nucleation or strengthening precipitates in aluminum alloys. 展开更多
关键词 Density functional theory FIRST-PRINCIPLE l1_(2)-Al_(3)X Mechanical property Defects Rare earths
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Thermal Stability and Strengthening Effect of Coherent Precipitates in a (FeCoNi)_(92)Al_(2.5)Ti_(5.5) High Entropy Alloy
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作者 Yuqi Liu Feng Wang +5 位作者 Songyang Chen Hui Wang Zhiping Xiong Khurram Yaqoob Zhangwei Wang Min Song 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2024年第9期1491-1500,共10页
The coarsening behavior and strengthening effect of L1_(2)-Ni_(3)(Ti,Al)precipitates in a face-centered-cubic(FCC)(FeCoNi)_(92)Al_(2.5)Ti_(5.5) high entropy alloy have been systematically investigated.The coherent L1_... The coarsening behavior and strengthening effect of L1_(2)-Ni_(3)(Ti,Al)precipitates in a face-centered-cubic(FCC)(FeCoNi)_(92)Al_(2.5)Ti_(5.5) high entropy alloy have been systematically investigated.The coherent L1_(2) precipitates,uniformly distributed throughout the FCC matrix,consistently retain a spherical shape.The coarsening rate coefficient of precipitate is determined by employing the Philippe-Voorhees(PV)model,suggesting excellent thermal stability.Furthermore,the elemental partitioning and compositional evolution of the L1_(2) precipitates is analyzed by atom probe tomography,which identify aluminum(Al)as the slowest diffusion species during the coarsening process.In addition,the precipitation strengthening effect is quantified to ascertain the optimal size of the precipitates.Our study enhances the understanding of precipitate coarsening in high entropy alloys,presenting valuable insights into their thermal stability and mechanical properties. 展开更多
关键词 High entropy alloy l1_(2)precipitates Coarsening kinetics Precipitation hardening
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手性固定相法分离芳香醇及芳酯对映体 被引量:6
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作者 张雪君 徐秀珠 +3 位作者 邵保海 沈报春 潘春秀 陈娟娟 《分析化学》 SCIE EI CAS CSCD 北大核心 2005年第12期1717-1721,共5页
在自制的涂敷型CDMPC和P irkle型(S,S)-W helk-O 1、(R,R)-DNB-DPEDA两类手性柱上,对1-苯乙醇、1-苯-1-丙醇及2-苯基丙酸甲酯进行了对映体分离。分别考察了在流动相正己烷中不同极性醇类添加剂、醇的浓度对这些溶质手性分离的影响,并研... 在自制的涂敷型CDMPC和P irkle型(S,S)-W helk-O 1、(R,R)-DNB-DPEDA两类手性柱上,对1-苯乙醇、1-苯-1-丙醇及2-苯基丙酸甲酯进行了对映体分离。分别考察了在流动相正己烷中不同极性醇类添加剂、醇的浓度对这些溶质手性分离的影响,并研究了溶质的体积大小及立体结构因素对手性分离的影响,由此探讨了这两类手性柱对这些化合物手性识别的机理,发现在(S,S)-W helk-O 1和(R,R)-DNB-DPEDA柱上溶质与固定相之间主要是吸引作用,而CDMPC手性识别的关键是溶质的体积大小、尤其是空间结构在手性空腔中的空间适应性,氢键作用对于CDMPC手性固定相的手性识别并不重要。 展开更多
关键词 手性固定相 1-苯乙醇 1-苯-1-丙醇 2-苯基丙酸甲酯 对映体分离
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A Sharp Nonasymptotic Bound and Phase Diagram of L1/2 Regularization 被引量:1
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作者 Hai ZHANG Zong Ben XU +2 位作者 Yao WANG Xiang Yu CHANG Yong LIANG 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2014年第7期1242-1258,共17页
We derive a sharp nonasymptotic bound of parameter estimation of the L1/2 regularization. The bound shows that the solutions of the L1/2 regularization can achieve a loss within logarithmic factor of an ideal mean squ... We derive a sharp nonasymptotic bound of parameter estimation of the L1/2 regularization. The bound shows that the solutions of the L1/2 regularization can achieve a loss within logarithmic factor of an ideal mean squared error and therefore underlies the feasibility and effectiveness of the L1/2 regularization. Interestingly, when applied to compressive sensing, the L1/2 regularization scheme has exhibited a very promising capability of completed recovery from a much less sampling information. As compared with the Lp (0 〈 p 〈 1) penalty, it is appeared that the L1/2 penalty can always yield the most sparse solution among all the Lv penalty when 1/2 〈 p 〈 1, and when 0 〈 p 〈 1/2, the Lp penalty exhibits the similar properties as the L1/2 penalty. This suggests that the L1/2 regularization scheme can be accepted as the best and therefore the representative of all the Lp (0 〈 p 〈 1) regularization schemes. 展开更多
关键词 l1/2 regularization phase diagram compressive sensing
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Short‑Term Splitting and Long‑Term Stability of Cuboidal Nanoparticles in Ni_(44)Co_(22)Cr_(22)Al_(6)Nb_(6) Multi‑Principal Element Alloy
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作者 Yitong Yang Jingyu Pang +6 位作者 Hongwei Zhang Aimin Wang Zhengwang Zhu Hong Li Guangquan Tang Long Zhang Haifeng Zhang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2023年第6期999-1006,共8页
Multi-principal element alloys(MPEAs)composed of thermally stable high-density cuboidal nanoparticles have revealed great potential for high-temperature applications.In this work,we systematically studied the growth b... Multi-principal element alloys(MPEAs)composed of thermally stable high-density cuboidal nanoparticles have revealed great potential for high-temperature applications.In this work,we systematically studied the growth behavior and coarsening kinetics of the cuboidal nanoparticles in Ni_(44)Co_(22)Cr_(22)Al_(6)Nb_(6) MPEA.In the initial stage of isothermal aging,the nanoparticles exhibit growth and split behavior,resulting in the improvement of mechanical performance,then the cuboidal nanoparticles retain superior thermal and mechanical stability during long-term isothermal aging.The 288 kJ/mol activation energy of Ni_(44)Co_(22)Cr_(22)Al_(6)Nb_(6) MPEA,which is higher than that in Ni-based superalloys,reveals the obvious elemental sluggish diffusion in Ni_(44)Co_(22)Cr_(22)Al_(6)Nb_(6) MPEA.Meanwhile,coarsening rate constant determined by the volume diffusion mechanism in Ni_(44)Co_(22)Cr_(22)Al_(6)Nb_(6) MPEA is 1–2 orders of magnitude less than that of the traditional Ni-based superalloys.The shortterm regulation and long-term stability of the cuboidal nanoparticles endow the Ni_(44)Co_(22)Cr_(22)Al_(6)Nb_(6) MPEA with superior mechanical performance and thermal stability for high temperature applications. 展开更多
关键词 Multi-principal element alloy l1_(2)nanoparticles Thermal stability Coarsening kinetics
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Microscopic phase field study of the antisite defect of Ni_3 Al in binary Ni-Al alloys 被引量:3
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作者 ZHANG Jing ,CHEN Zheng,LU YanLi,ZHANG MingYi & WANG YongXin State Key Laboratory of Solidification Processing School of Material Science and Engineering,Northwestern Polytechnical University,Xi’an 710072,China 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2010年第11期2047-2053,共7页
The temporal evolution feature of a microscopic phase field model is utilized to study the antisite defects of L1 2-Ni 3 Al;this is quite different from other physicist’ interests.There are mainly two points in brief... The temporal evolution feature of a microscopic phase field model is utilized to study the antisite defects of L1 2-Ni 3 Al;this is quite different from other physicist’ interests.There are mainly two points in brief.Firstly,antisite defects Ni Al and Al Ni ,which are caused by the deviation from the stoichiometric Ni 3 Al,coexist in the Ni 3 Al phase.The surplus Ni atom in the Ni-rich side is prone to substitute Al thus producing the antisite defect Ni Al that maintains the stability of the L1 2 structure.In other case,the surplus Al atom in the Al-rich side is accommodated by a Ni sublattice consequently giving rise to antisite defect Al Ni .The calculated equilibrium occupancy probability of Ni Al is much higher than that of Al Ni .This point is generally in line with other theoretical and experimental works.Additionally,both Ni Al and Al Ni have a strong negative correlation to time step during the disorder-order transformation.Since the initial value of Ni Al and Al Ni on each site of the matrix is right at the concentration that we set,we can observe the decrease process of Ni Al and Al Ni from the initial disordered high anti-structure state to their respective equilibrium state,i.e.to the result of the ordering process further coarsening. 展开更多
关键词 antisite DEFECT l1 2 -Ni 3 AL temporal evolution MICROSCOPIC phase field model
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Al_(11.5)Cr_(16)Fe_(17)Ni_(51.5)V_(4)高熵合金中L1_(2)结构纳米共格相的析出行为及其对力学性能的影响
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作者 印家辉 林耀军 《金属热处理》 CAS 2024年第11期29-37,共9页
以Al_(11.5)Cr_(16)Fe_(17)Ni_(51.5)V_(4)高熵合金为研究对象,研究了固溶处理成单相固溶体的该合金在600℃时效不同时间后的微观组织和拉伸性能。结果表明,经1150℃保温7 min再结晶退火/固溶处理后,该合金组织为单相FCC固溶体。600℃... 以Al_(11.5)Cr_(16)Fe_(17)Ni_(51.5)V_(4)高熵合金为研究对象,研究了固溶处理成单相固溶体的该合金在600℃时效不同时间后的微观组织和拉伸性能。结果表明,经1150℃保温7 min再结晶退火/固溶处理后,该合金组织为单相FCC固溶体。600℃时效处理后,形成了具有L1_(2)结构的纳米尺寸球状富Ni、Al元素的γ′-Ni_(3)Al析出相。随时效时间延长,γ′析出相的尺寸和体积分数单调增加,晶粒尺寸轻微长大。合金的屈服强度从306 MPa增加到863 MPa,抗拉强度从560 MPa增加到1272 MPa,同时合金保持了良好的韧性(均匀延伸率34.1%~17.7%)。时效过程中,合金强度的增加,主要归因于γ′相的析出强化,其析出强化的机制为位错切过机制。γ′相析出强化效应随γ′相尺寸和体积分数的增加而增加。合金的良好韧性取决于γ′析出相的共格特征和极小的纳米尺寸,降低了析出相/基体界面的应力集中。 展开更多
关键词 高熵合金 时效处理 析出强化 l1_(2)结构γ′析出相 力学性能
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稳定表达人源GABA_(A)R-CHO细胞株的建立 被引量:1
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作者 张毅 王陈 +5 位作者 石晶晶 陈学军 张瑞华 靳倩 石童 李丽琴 《中国生物工程杂志》 CAS CSCD 北大核心 2022年第3期38-46,共9页
目的:构建α_(1)亚基诱导表达、β_(2)和γ_(2L)亚基稳定表达的人源α_(1)β_(2)γ_(2L)-GABA_(A)R-CHO(Chinese hamster ovary)细胞株。方法:从人cDNA文库中扩增α_(1)、β_(2)、γ_(2L)亚基编码基因,分别构建亚基表达载体;将三个亚基... 目的:构建α_(1)亚基诱导表达、β_(2)和γ_(2L)亚基稳定表达的人源α_(1)β_(2)γ_(2L)-GABA_(A)R-CHO(Chinese hamster ovary)细胞株。方法:从人cDNA文库中扩增α_(1)、β_(2)、γ_(2L)亚基编码基因,分别构建亚基表达载体;将三个亚基表达载体共转染CHO-K1细胞,通过抗性筛选、膜电位检测法进行稳定表达克隆筛选;通过qPCR、Western blot对亚基表达进行鉴定;以激动剂GABA、阳性变构调节剂地西泮(diazepam,Dia)、拮抗剂荷包牡丹碱(bicuculine)为工具药,采用全细胞膜片钳方法及膜电位检测法对稳定表达细胞的药理学功能进行鉴定。结果:经克隆筛选获得表达量较高的α_(1)β_(2)γ_(2L)-GABA_(A)R-CHO并对其亚基表达鉴定,结果显示该细胞稳定表达α_(1)、β_(2)、γ_(2L)亚基,构建的α_(1)β_(2)γ_(2L)-GABA_(A)R-CHO细胞仅在加入四环素(tetracyclin)诱导的情况下表达α_(1)亚基并与β_(2)、γ_(2L)组装成具有功能活性的α_(1)β_(2)γ_(2L)-GABA_(A)R;对其进行全细胞膜片钳检测研究发现,GABA可对其产生激动效应,引起α_(1)β_(2)γ_(2L)-GABA_(A)R-CHO细胞产生氯离子通道特征性电流变化,Dia可剂量依赖性地增强GABA对α_(1)β_(2)γ_(2L)-GABA_(A)R的激动效应;在膜电位检测研究中,获得GABA激动效应EC_(50)为(177.72±15.92)nmol/L,Dia变构效应EC_(50)为(3.63±0.52)μmol/L,拮抗剂Bicuculine拮抗效应IC50为(538.83±29.55)nmol/L。结论:通过采用诱导表达策略,成功构建了α_(1)β_(2)γ_(2L)-GABA_(A)R-CHO稳定表达细胞株,该细胞株具有对激动剂、阳性变构剂、拮抗剂特异性检测的药理学功能。 展开更多
关键词 α_(1)β_(2)γ_(2L)-GABA_(A)R-CHO 诱导表达 膜电位检测 GABA 地西泮
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