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Mechanism and morphology evolution of the O phase transformation in Ti-22Al-25Nb alloy 被引量:4
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作者 Zong Yingying Wang Jiwei +2 位作者 Shao Bin Tang Wei Shan Debin 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第30期97-106,共10页
The phase transformation and microstructure in Ti-22Al-25Nb alloy are extremely complex.In this work,the morphology evolution of the O phase during the heating and cooling process was investigated by electron backscat... The phase transformation and microstructure in Ti-22Al-25Nb alloy are extremely complex.In this work,the morphology evolution of the O phase during the heating and cooling process was investigated by electron backscatter diffraction(EBSD)and first-principles calculations.The results show that the O→α_(2)phase transformation process during the heating process is as follows:spheroidization of the O phase occurs first,then theα_(2)phase nucleates in the spheroidized O phase,grows and replaces the O phase,completing the O→α_(2)phase transformation.In the meanwhile,the diffusion of Nb from Nb-poor O to Nb-rich B2 phases is a back-diffusion process.According to first-principles calculations,the driving force of the O→α_(2)phase transformation is the difference in the free energies of formation for the two phases(0.09 eV/atom).When the Nb content is greater than 15.625%,the lattice distortion of theα_(2)phase sharply increases,and the distortion energy drives the back-diffusion of Nb.During the cooling process,theα_(2)→O phase transformation is difficult and slow due to the difficult diffusion of Nb from the B2 toα_(2)phases.When holding for 60 min at 960℃,the coarseα_(2)phase gradually transforms to the O phase from the margin to the inside,forming a dispersed mixed structure of the O andα_(2)phases.During the B2→O transformation,the nucleation of the O phase induces a high stress region,in the range of approximately 200 nm. 展开更多
关键词 Ti-22Al-25Nb alloy phase transformation MICRoSTRUCTURE o phase FIRST-PRINCIPLES
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注凝成型反应烧结Si_(3)N_(4)-O′-Sialon复相陶瓷的显微结构和力学性能
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作者 张电 柴聪 +2 位作者 刘静 刘璇 刘一军 《宇航材料工艺》 北大核心 2025年第3期39-47,共9页
注凝成型反应烧结Si_(3)N_(4)基陶瓷具有优异的性能,被广泛应用于有色金属熔炼和铸造等领域的关键构件中,但其气密性、抗氧化性和强韧性存在不足。本文以Si粉和黏土为原料制备注凝成型反应烧结Si_(3)N_(4)-O′-Sialon复相陶瓷。结果表明... 注凝成型反应烧结Si_(3)N_(4)基陶瓷具有优异的性能,被广泛应用于有色金属熔炼和铸造等领域的关键构件中,但其气密性、抗氧化性和强韧性存在不足。本文以Si粉和黏土为原料制备注凝成型反应烧结Si_(3)N_(4)-O′-Sialon复相陶瓷。结果表明,黏土能大幅改善浆料、坯体和烧结等工艺性能;黏土高温液相产生的封闭开口气孔和烧结致密化作用能显著降低显气孔率并提高弯曲强度。高温液相的溶解和氮化反应能促进β-Si_(3)N_(4)和O′-Sialon从液相中析晶,随着氮化温度升高,O′-Sialon相由无定型细小颗粒,发育为结晶完整的针状、柱状和多面体状大尺寸晶体,产生强韧化作用。合理的Si含量为70%~80%、氮化温度为1500~1600℃,Si含量80%、温度1600℃试样的显气孔率、体积密度、弯曲强度、断裂功和临界应力强度因子分别为14.15%、2.22 g/cm^(3)、114.0 MPa、450.3 J/m^(2)和1.88 MPa·m^(1/2)。 展开更多
关键词 氮化硅 奥赛隆 复相陶瓷 反应烧结 力学性能
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Direct evidence for competition between metastable ω and equilibrium α phases in aged β-type Ti alloys 被引量:1
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作者 Shun Guo Qing-Kun Meng +1 位作者 Hong-Ping Li Xin-Qing Zhao 《Rare Metals》 SCIE EI CAS CSCD 2014年第4期390-393,共4页
Precipitation response of a recently developed β-type Ti-25Nb-2Mo-4Sn alloy (wt%) during aging was investigated in detail. Experimental results indicate that the metastable co or equilibrium α phase can form alter... Precipitation response of a recently developed β-type Ti-25Nb-2Mo-4Sn alloy (wt%) during aging was investigated in detail. Experimental results indicate that the metastable co or equilibrium α phase can form alternatively even under the same aging condition, depending on the condition prior to the aging, i.e., solution treatment or severe cold rolling. This provides, for the first time, the direct evidence for the competition between ω and α in aged β-type Ti alloys. This peculiar aging response is found to be closely related to high-density dislocations and grain boundaries which suppress the formation of ω but favor the precipitation of fine α phase. 展开更多
关键词 β-Type Ti alloy phase competition o~ phase at phase
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Growth of β-Ga_2O_3 Films on Sapphire by Hydride Vapor Phase Epitaxy 被引量:4
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作者 Ze-Ning XIONG Xiang-Qian XIU +7 位作者 Yue-Wen LI Xue-Mei HUA Zi-Li XIE Peng CHEN Bin LIU Ping HAN Rong ZHANG You-Dou ZHENG 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第5期141-143,共3页
Two-inch Ga_2O_3 films with(ˉ201)-orientation are grown on c-sapphire at 850–1050°C by hydride vapor phase epitaxy. High-resolution x-ray diffraction shows that pure β-Ga_2O_3 with a smooth surface has a hig... Two-inch Ga_2O_3 films with(ˉ201)-orientation are grown on c-sapphire at 850–1050°C by hydride vapor phase epitaxy. High-resolution x-ray diffraction shows that pure β-Ga_2O_3 with a smooth surface has a higher crystal quality, and the Raman spectra reveal a very small residual strain in β-Ga_2O_3 grown by hydride vapor phase epitaxy compared with bulk single crystal. The optical transmittance is higher than 80% in the visible and near-UV regions, and the optical bandgap energy is calculated to be 4.9 e V. 展开更多
关键词 Growth of Ga2o3 Films on Sapphire by Hydride Vapor phase Epitaxy XRD
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热处理中双尺寸O相的变体选择和析出行为 被引量:1
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作者 李宗泽 卫俊鑫 +4 位作者 高志荣 袁振豪 曹守臻 韩建超 贾燚 《塑性工程学报》 北大核心 2025年第1期218-227,共10页
为提高锻态Ti_(2)AlNb基合金后续热变形能力,对多向锻造后的Ti_(2)AlNb基合金进行了固溶+时效的热处理。研究分析了热处理前后的组织演变、力学性能以及O相的析出行为。结果表明:多向锻造后的空冷的Ti_(2)AlNb合金,组织内析出大量针状O... 为提高锻态Ti_(2)AlNb基合金后续热变形能力,对多向锻造后的Ti_(2)AlNb基合金进行了固溶+时效的热处理。研究分析了热处理前后的组织演变、力学性能以及O相的析出行为。结果表明:多向锻造后的空冷的Ti_(2)AlNb合金,组织内析出大量针状O相,位错密度高,晶粒尺寸大,导致其伸长率较低。经过热处理后形成了B2基体+双尺板条/针状O相组织,位错密度降低,α_(2)相以包析反应生成了rim-O相;晶粒内部的析出O相包含4种变体。O相在小角度晶界处沿两侧生长分布,而在大角度晶界处只沿单侧析出生长。热处理后的Ti_(2)AlNb合金表现出显著提高的伸长率,增加了后续热变形的稳定性。 展开更多
关键词 Ti_(2)AlNb合金 热处理 o相析出行为 显微组织 力学性能
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Subsolidus Phase Relations in the System MgO-SiO_2-Cr-O and Thermodynamic Properties of Related Cr^(2+)-Containing End-members
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作者 H.St.CO' Neill F.Seifert 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1996年第4期420-434,共15页
Subsolidus phase relations have been determined in the systems SiO2-Cr-O and MgO-SiO2-Cr-O in equilibrium with metallic Cr, at 1100 to 1500℃ and 0 to 2.88 GPa. The results show that there are no ternary phases in the... Subsolidus phase relations have been determined in the systems SiO2-Cr-O and MgO-SiO2-Cr-O in equilibrium with metallic Cr, at 1100 to 1500℃ and 0 to 2.88 GPa. The results show that there are no ternary phases in the SiO2-Cr-O system at these conditions, i.e., only the assemblage eskolaite-Cr-metal-quartz (or tridymite) is found. In the MgO-containing system, however, extensive substitution of Cr2+ for Mg is observed in (Mg, Cr2+)2SiO4 olivine, (Mg, Cr2+)2Si2O6 pyroxene, and (Mg, Cr2+)Cr2O4 spinel. Cr3+ levels in olivine and pyroxene are below detection limits. The pyroxene is orthohombic at XCrPx2+ < 0.2, monoclinic at higher XCrPx2+ . Thestructure of the spinels becomes tetragonally distorted at XCr2+Sp >0.2. The experimental datahave been fitted to a thermodynamic model, and the authors obtained the mixing parameter (W) of Mg-Cr2+ in olivine, pyroxene and spinel, and the relation between temperatures and free energies of formation for the end-members: Cr2+-olivine (Cr2SiO4), Cr2+-pyroxene (Cr2Si2O6) and Cr2+-spinel (Cr3O4). 展开更多
关键词 Mgo-Sio_2-Cr-o system phase equilibrium thermodynamic properties
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Thermodynamics and Phase Equilibrium of Cu-Ce-O,Cu-Ce-S,Cu-Ce-O-S Liquid Solutions
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作者 DU Ting LI Guo Dong 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 1995年第1期10-14,共4页
Thermodynamics of Cu-Ce-O,Cu-Ce-S and Cu-Ce-0-S solutions at 1200℃ were studied by using solid electrolyte cell and chemical equilibrium method.The equilibrium constant of deoxidation,desulfurization and deoxysulfuri... Thermodynamics of Cu-Ce-O,Cu-Ce-S and Cu-Ce-0-S solutions at 1200℃ were studied by using solid electrolyte cell and chemical equilibrium method.The equilibrium constant of deoxidation,desulfurization and deoxysulfurization by Ce,the Gibbs standard reaction free energies of the formation of Ce_2O_3,CeS and Ce_2O_2S in Cu-base solution,activity interaction coefficients of S and Ce,temperature dependence of standard reaction free energy of solution of Ce in Cu,self-interaction coefficients of Ce in liquid Cu have been obtained.The phase precipitation diagram for Cu-CeS-O system has been plotted.The thermodynamic condition of the existence of Ce_2O_3,CeS and Ce_2O_2S in liquid Cu has been determined.It provides the basis for predicting the sequence and the type of equilibrium inclusions of Ce formed in Cu-base solution. 展开更多
关键词 Cu liquid Ce o S thermodynamic property phase diagram
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Influence of Gd_2O_3 and Yb_2O_3 Co-doping on Phase Stability,Thermo-physical Properties and Sintering of 8YSZ 被引量:33
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作者 ZHANG Yanli GUO Lei +3 位作者 YANG Yongping GUO Hongbo ZHANG Hongju GONG Shengkai 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2012年第6期948-953,共6页
The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings (TBCs) materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3... The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings (TBCs) materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3 mol% Yb2O3 (GYb-YSZ) powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed. 展开更多
关键词 thermal barrier coatings (TBCs) Gd2o3 and Yb2o3 co-doped 8YSZ (GYb-YSZ) phase stability sintering ther-mo-physical properties
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Synthesis of diethers derived from furoin by phase transfer catalysis under microwave irradiation
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作者 Feng Zhang Ya Zhuo Li Da Wei Gao Ji Kui Sun Yu Min Zhang 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第7期791-794,共4页
A series of new diethers were obtained by alkylation of furoin under microwave irradiation (MWI) in phase transfer catalysis (PTC) conditions. The products of alkyl halides were synthesized in good yields (〉75%... A series of new diethers were obtained by alkylation of furoin under microwave irradiation (MWI) in phase transfer catalysis (PTC) conditions. The products of alkyl halides were synthesized in good yields (〉75%) within a few minutes, and the products of dihalides were synthesized in fair yields (about 45%). The yields are dramatically improved compared to conventional heating under the same conditions, in spite of similar profiles of rising in temperature. 展开更多
关键词 Microwave irradiation FURoIN phase transfer catalysis o-ALKYLATIoN
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Pressure-induced phase transition of B-type Y_2O_3
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作者 张倩 巫翔 秦善 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第9期114-118,共5页
The synthesized monoclinic(B-type) phase of Y2O3 has been investigated by in situ angle-dispersive x-ray diffraction in a diamond anvil cell up to 44 GPa at room temperature. A phase transition occurs from monoclini... The synthesized monoclinic(B-type) phase of Y2O3 has been investigated by in situ angle-dispersive x-ray diffraction in a diamond anvil cell up to 44 GPa at room temperature. A phase transition occurs from monoclinic(B-type) to hexagonal(A-type) phase at 23.5 GPa and these two phases coexist even at the highest pressure. Parameters of isothermal equation of state are V0= 69.0(1)A3, K0= 159(3) GPa, K0= 4(fixed) for the B-type phase and V0= 67.8(2) A3, K0= 156(3) GPa,K'0= 4fixed for the A-type phase. The structural anisotropy increases with increasing pressure for both phases. 展开更多
关键词 Y2o3 x-ray diffraction pressure-induced phase transition equation of state
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Efficient and Convenient Synthesis of Diethers from Furoin Under Ultrasound and Solid-liquid Phase Transfer Catalysis Conditions
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作者 ZHANG Feng LI Ya-zhuo +5 位作者 WANG Yun-xin GAO Da-wei SUN Ji-kui ZHANG Yu-min ZHAO Tian-qi CHEN Xiao-dong 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2007年第4期486-488,共3页
Compounds having an active hydroxy group, such as, acyloins can be easily alkylated by alkyl halides in the presence of a phase transfer catalyst (PTC). The reaction is usually carried out in the presence of con-cen... Compounds having an active hydroxy group, such as, acyloins can be easily alkylated by alkyl halides in the presence of a phase transfer catalyst (PTC). The reaction is usually carried out in the presence of con-centrated aqueous sodium or potassium hydroxide and a phase transfer catalyst, such as, quaternary ammonium salts^[1-3] species, miscible which facilitate the interphase transfer of making reactions between reagents in two im-phases possible. The reaction involves a series of equilibrium and mass-transfer steps. 展开更多
关键词 ULTRASoUND phase transfer catalysis Furoin o-ALKYLATIoN
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Fe-Al-O三元系热力学优化
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作者 丁叶晴 鲁晓刚 《上海金属》 2025年第5期97-102,共6页
对Fe-Al-O及其子二元体系热力学进行了系统评估。采用CALPHAD方法和缔合物模型描述液相,对Fe-Al、Fe-O、FeO-Al2 O3及Fe2 O3-Al2 O3体系进行了评估和优化。结果表明:优化的相图和热力学数据与试验结果相符,可作为现有冶金热力学数据库... 对Fe-Al-O及其子二元体系热力学进行了系统评估。采用CALPHAD方法和缔合物模型描述液相,对Fe-Al、Fe-O、FeO-Al2 O3及Fe2 O3-Al2 O3体系进行了评估和优化。结果表明:优化的相图和热力学数据与试验结果相符,可作为现有冶金热力学数据库的重要补充。 展开更多
关键词 CALPHAD 方法 Fe-Al-o 体系 相图 热力学优化
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固相体积分数对O型球阀空化特性的影响
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作者 周兆年 吴斌彬 +4 位作者 华霆锋 王照彤 金志江 李文庆 钱锦远 《过程工程学报》 北大核心 2025年第3期241-248,共8页
O型球阀是煤化工行业中重要的流体控制设备,在工作过程中,球阀内部容易发生空化现象。球阀工质为含有固相颗粒的流体,颗粒的体积分数会对空化产生影响但机制尚不明确。针对这一问题,使用数值模拟的手段,探究了不同阀球转角下,固相体积... O型球阀是煤化工行业中重要的流体控制设备,在工作过程中,球阀内部容易发生空化现象。球阀工质为含有固相颗粒的流体,颗粒的体积分数会对空化产生影响但机制尚不明确。针对这一问题,使用数值模拟的手段,探究了不同阀球转角下,固相体积分数对球阀内空化的影响。结果表明,当阀球转角为30°以及45°时,阀内并无空化发生;阀球转角为60°时,低浓度的颗粒会削弱阀内的空化程度,而浓度大于10%的颗粒会促进空化发生;阀球转角为75°时,不同浓度的颗粒均会促进阀内的空化。本工作揭示了固相体积分数对O型球阀空化特性的影响机理,对于控制O型球阀工作环境以及多相流仿真方面具有一定的指导作用。 展开更多
关键词 o型球阀 空化 固相体积 Mixture模型 空化数 多相流
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THERMODYNAMICS AND PHASE EQUILIBRIUM OF Cu-Y-O,Cu-Y-S,Cu-Y-O-S LIQUID SOLUTIONS
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作者 Ting, Du Guodong, Li 《中国有色金属学会会刊:英文版》 EI CSCD 1995年第3期16-20,共5页
THERMODYNAMICSANDPHASEEQUILIBRIUMOFCu-Y-O,Cu-Y-S,Cu-Y-O-SLIQUIDSOLUTIONS¥Du,Ting;Li,Guodong(CentralIronandSt... THERMODYNAMICSANDPHASEEQUILIBRIUMOFCu-Y-O,Cu-Y-S,Cu-Y-O-SLIQUIDSOLUTIONS¥Du,Ting;Li,Guodong(CentralIronandSteelResearchinstit... 展开更多
关键词 Y o S and CU LIQUID thermodynamic property phase DIAGRAM
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CHARACTERISTICS OF TROPICAL CYCLONE GENESIS IN THE WESTERN NORTH PACIFIC DURING THE DEVELOPING AND DECAYING PHASES OF TWO TYPES OF EL NIO
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作者 钟佩瑄 李天明 《Journal of Tropical Meteorology》 SCIE 2015年第1期14-22,共9页
During the developing phase of central Pacific El Nio(CPEN), more frequent TC genesis over the northwest quadrant of the western North Pacific(WNP) is attributed to the horizontal shift of environmental vorticity fi... During the developing phase of central Pacific El Nio(CPEN), more frequent TC genesis over the northwest quadrant of the western North Pacific(WNP) is attributed to the horizontal shift of environmental vorticity field.Such a northwestward shift resembles the La Nia composite, even though factors that cause the shift differ(in the La Nia case the relative humidity effect is crucial). Greater reduction of TC frequency over WNP happened during the decaying phase of eastern Pacific El Nio(EPEN) than CPEN, due to the difference of the anomalous Philippine Sea anticyclone strength. The TC genesis exhibits an upward(downward) trend over the northern(southern) part of the WNP,which is linked to SST and associated circulation changes through local and remote effects. 展开更多
关键词 tropical cyclone genesis western North Pacific two types of El Ni觡o growing and decaying phases gene-sis trends
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SYNTHESIS AND CHARACTERISTICS OF A CHELATING RESIN AS AN EXTRACTANT AND CHROMOGENIC REAGENT OF HEAVY METAL IONS IN SOLID PHASE EXTRACTION 被引量:4
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作者 张田林 Hui-min Ma +2 位作者 Jia-jia Wang Cai-yan Zhu Bing-bing Wang 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2013年第8期1108-1116,共9页
A new chelating resin (CPS-DMA-SABA) was synthesized with the chloromethylated crossqinked polystyrene porous beads (CPS) as raw materials, which were bonded with salicylidene-o-aminobenzoic acid (SABA) on the s... A new chelating resin (CPS-DMA-SABA) was synthesized with the chloromethylated crossqinked polystyrene porous beads (CPS) as raw materials, which were bonded with salicylidene-o-aminobenzoic acid (SABA) on the surface via a quaternary ammonium unit as a linker. The results showed that CPS-DMA-SABA would easily change into a zwitterionic chelating resin (CPS-DMA-SABZ) when washed with distilled water. CPS-DMA-SABA was characterized by elemental analysis, infrared spectra and thermo-gravimetric analysis. The ion sorption capacities of CPS-DMA-SABA were found to be 1916 μg/g for Zn2+ withpH at 4.5, 1620μg/g for Cu2+ with pH at 6.2, 1291 μg/g for Ni2+ withpH at 6.6 and 780 μg/g for Cr3+ withpH at 5.5, respectively. The experiments showed CPS-DMA-SABA also changed its color when meeting with the metal ion in the aqueous solution. As a consequence, CPS-DMA-SABA can not only be used as a solid phase extractant but also an indicator for confirming the heavy metal ion in solutions. 展开更多
关键词 Solid phase extractant Zwitterionic chelating resin Heavy metal ion o-Aminobenzoic acid Synthesis.
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The Metastable Phase Equilibria of the MeX-MgCl_2-H_2O Systems
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作者 ZENG Ying YU Xudong +1 位作者 MU Pengtao FENG Shan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期398-398,共1页
1 Introduction The Pingluoba brine,which characterized as high concentration with sodium,potassium,boron,lithium,and rubidium,possess great development value.The main composition of the brine can be summarized to the
关键词 CL The Metastable phase Equilibria of the MeX-MgCl2-H2o Systems
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IN-SITU HVEM STUDY ON PHASE TRANSITION OF YBa_2Cu_3O_(7-x) SUPERCONDUCTING COMPOUND IN PROCESS OF HEATING
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作者 王瑞坤 邸秀萱 +4 位作者 王振海 贺庆 俞定安 周和平 王英 《Journal of Rare Earths》 SCIE EI CAS CSCD 1990年第2期99-103,共5页
In-situ HVEM observation on phase transition of the YBa_2Cu_3O_(7-x) superconducting compound in pro- cess of heating was carried out,and high temperature X-ray diffraction analysis in air and X-ray diffraction phase ... In-situ HVEM observation on phase transition of the YBa_2Cu_3O_(7-x) superconducting compound in pro- cess of heating was carried out,and high temperature X-ray diffraction analysis in air and X-ray diffraction phase analysis for the sample treated in vacuum condition were made.The results showed that the temperature of phase transition is related to oxygen content in the sample and in general,is 100℃ to 120℃ lower in vacu- um condition than in air.At 320℃ to 350℃ twin bands begin to disappear,and some Cu_2O are formed on the surface of the sample and transit from orthorhombic YBa_2Cu_3O_(7-x) to arthorhombic Y_2BaCuO_5 compound. This transition was completed at about 500℃.Above 900℃,this compound consists of the Y_2BaCuO_5, BaCuO_2,Y_2O_3 and some other minor compounds.No phase transition was observed during cooling the sample. 展开更多
关键词 HVEM SUPERCoNDUCTING CoMPoUND IN PRoCESS oF HEATING IN-SITU HVEM STUDY oN phase TRANSITIoN oF YBa2Cu3o Cu
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材料成型过程O相(Ti_(2)AlNb)合金的组织与性能演化
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作者 谢志龙 李亚非 +2 位作者 高军 佟飞 向顺成 《大型铸锻件》 2025年第1期18-25,共8页
以有序O相为主要成分的Ti_(2)AlNb合金,物理、化学、力学性能优异,但成型工艺性能较差,合金组织、性能依赖于加工成型工艺参数。本综述以Ti_(2)AlNb合金的组织形貌、相组成、力学性能为对象,总结锻造、热处理、粉末热等静压等过程中组织... 以有序O相为主要成分的Ti_(2)AlNb合金,物理、化学、力学性能优异,但成型工艺性能较差,合金组织、性能依赖于加工成型工艺参数。本综述以Ti_(2)AlNb合金的组织形貌、相组成、力学性能为对象,总结锻造、热处理、粉末热等静压等过程中组织-性能演化规律:Ti_(2)AlNb合金的O相为强化强,且存在多种相变形式。通过改变O相含量与形貌、B_(2)相含量、α_(2)相含量与分布从而实现调控合金力学性能。 展开更多
关键词 Ti_(2)AlNb合金 o 成型工艺 显微组织
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Octa-<i>O</i>-Methoxy Resorcin [4] Arene Amberlite XAD-4 Polymeric Chelating Resin for Solid Phase Extraction, Preconcentration, Separation and Trace Determination of Ni(II), Cu(II), Zn(II) and Cd(II) Ions
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作者 Disha J. Vyas Bharat A. Makwana +1 位作者 Keyur D. Bhatt Vinod K. Jain 《American Journal of Analytical Chemistry》 2013年第5期238-251,共14页
Synthetic resin, Amberlite XAD-4 was linked covalently with the third generation supramolecule, octa-O-methoxy resorcin [4] arene through -N=N-group to form chelating resin, which has been characterized and effectivel... Synthetic resin, Amberlite XAD-4 was linked covalently with the third generation supramolecule, octa-O-methoxy resorcin [4] arene through -N=N-group to form chelating resin, which has been characterized and effectively used for the separation and preconcentration of metal ions such as Ni(II), Cu(II), Zn(II) and Cd(II). Critical parameters such as pH, flow rate, sorption capacity, breakthrough studies, distribution coefficient, preconcentration factor, concentration of eluting agents responsible for quantitative extraction of metal ions were optimized. The synthesized resin showed good binding affinity towards Ni(II), Cu(II), Zn(II) and Cd(II) under selective pH conditions. Good breakthrough capacity and fast exchange kinetics of the resin lead to effective separation of metal ions from their binary and ternary mixture by column method on the basis of pH and eluting agents. The resin could be reused for about 8 -10 cycles. The proposed method having the analytical data with the relative standard deviation (RSD) 2% and with recoveries of analytes higher than 98%, reflects upon the reproducibility and reliability of the method which has been successfully applied in the separation and determination of Ni(II), Cu(II), Zn(II) and Cd(II) ions in synthetic, natural and ground water samples. 展开更多
关键词 SEPARATIoN PRECoNCENTRATIoN Amberlite XAD-4 octa--o-Methoxy Resorcin [4] ARENE Solid phase Extraction
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