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Laser-optimized Pt-Y alloy nanoparticles embedded in Pt-Y oxide matrix for high stability and ORR electrocatalytic activity
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作者 Riccardo Brandiele Andrea Guadagnini +9 位作者 Mattia Parnigotto Federico Pini Vito Coviello Denis Badocco Paolo Pastore Gian Andrea Rizzi Andrea Vittadini Daniel Forrer Vincenzo Amendola Christian Durante 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期508-520,共13页
The development of active yet stable catalysts for oxygen reduction reaction(ORR)is still a major issue for the extensive permeation of fuel cells into everyday technology.While nanostructured Pt catalysts are to date... The development of active yet stable catalysts for oxygen reduction reaction(ORR)is still a major issue for the extensive permeation of fuel cells into everyday technology.While nanostructured Pt catalysts are to date the best available systems in terms of activity,the same is not true for stability,particularly under operating conditions.In this work,Pt_(Х)Y alloy nanoparticles are proposed as active and durable electrocatalysts for ORR.Pt_(Х)Y nanoalloys are synthesized and further optimized by laser ablation in liquid followed by laser fragmentation in liquid.The novel integrated laser-assisted methodology succeeded in producing Pt_(Х)Y nanoparticles with the ideal size(<10 nm)of commercial Pt catalysts,yet resulting remarkably more active with E_(1/2)=0.943 V vs.RHE,specific activity=1095μA cm^(-2) and mass activity>1000 A g^(-1).At the same time,the nanoalloys are embedded in a fine Pt oxide matrix,which allows a greater stability of the catalyst than the commercial Pt reference,as directly verified on a gas diffusion electrode. 展开更多
关键词 ELECTROCaTaLySIS GDE ORR Pt_(2)y Pt_(3)y LaL LFL Oxide support PTO NaNOaLLOyS
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Adaptive Window Based 3-D Feature Selection for Multispectral Image Classification Using Firefly Algorithm
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作者 M.Rajakani R.J.Kavitha A.Ramachandran 《Computer Systems Science & Engineering》 SCIE EI 2023年第1期265-280,共16页
Feature extraction is the most critical step in classification of multispectral image.The classification accuracy is mainly influenced by the feature sets that are selected to classify the image.In the past,handcrafte... Feature extraction is the most critical step in classification of multispectral image.The classification accuracy is mainly influenced by the feature sets that are selected to classify the image.In the past,handcrafted feature sets are used which are not adaptive for different image domains.To overcome this,an evolu-tionary learning method is developed to automatically learn the spatial-spectral features for classification.A modified Firefly Algorithm(FA)which achieves maximum classification accuracy with reduced size of feature set is proposed to gain the interest of feature selection for this purpose.For extracting the most effi-cient features from the data set,we have used 3-D discrete wavelet transform which decompose the multispectral image in all three dimensions.For selecting spatial and spectral features we have studied three different approaches namely overlapping window(OW-3DFS),non-overlapping window(NW-3DFS)adaptive window cube(AW-3DFS)and Pixel based technique.Fivefold Multiclass Support Vector Machine(MSVM)is used for classification purpose.Experiments con-ducted on Madurai LISS IV multispectral image exploited that the adaptive win-dow approach is used to increase the classification accuracy. 展开更多
关键词 Multispectral image modifiedfirefly algorithm 3-D feature extraction feature selection multiclass support vector machine CLaSSIFICaTION
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Effects of Y addition on structural and mechanical properties of CuZrAl bulk metallic glass 被引量:6
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作者 许宏伟 杜宇雷 邓昱 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第4期842-846,共5页
The effects of Y addition on the structural and mechanical properties of CuZrAl bulk metallic glass(BMG) were studied.The results show that the glass forming ability of CuZrAl system is improved by the addition of Y... The effects of Y addition on the structural and mechanical properties of CuZrAl bulk metallic glass(BMG) were studied.The results show that the glass forming ability of CuZrAl system is improved by the addition of Y and the fracture strength decreases with Y addition due to the reduction of binding energy induced by Y.The fracture surface is dominated by vein-like patterns in Cu45Zr48Al7 bulk metallic glass,and changes to smooth regions in Cu46Zr42Al7Y5 BMG.TEM observation shows that Cu45Zr48Al7 BMG has a composite microstructure of nanocrystalline phases dispersed in amorphous matrix.However,the Cu46Zr42Al7Y5 BMG shows a fully amorphous structure. 展开更多
关键词 bulk metallic glass Cu-based alloy y addition
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Influence of casting module on corrosion behavior of Mg-11Gd-3Y alloy 被引量:2
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作者 刘贤斌 单大勇 +2 位作者 宋影伟 陈荣石 韩恩厚 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第4期903-911,共9页
The influences of two kinds of casting modules of metal casting (MC) and expandable pattern casting (EPC) on the corrosion behavior of Mg-11Gd-3Y alloy were studied by electrochemical measurements, scanning electr... The influences of two kinds of casting modules of metal casting (MC) and expandable pattern casting (EPC) on the corrosion behavior of Mg-11Gd-3Y alloy were studied by electrochemical measurements, scanning electron microscopy (SEM) observation, X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. It is found that the quantity of the Mg 24 (Gd, Y) 5 phase in MC is more than that in EPC due to the cooling rate. There is more alloying element dissolved in the matrix compared with MC. For EPC, the galvanic corrosion effect between the matrix and the Mg 24 (Gd, Y) 5 phase decreases and the corrosion resistance increases compared with the MC. The chief corrosion mode for Mg-11Gd-3Y alloy is pitting corrosion because most of the alloying elements are transformed into intermetallic phases. The average corrosion rate of the MC alloy in the immersion test is five times higher than that of EPC alloy and yttrium is present in the product film, which will provide increased protection for Mg-11Gd-3Y alloy. The electrochemical measurements and immersion test show that the EPC process increases the corrosion resistance compared with the MC Mg-11Gd-3Y alloy. 展开更多
关键词 Mg-11Gd-3y alloy corrosion behavior casting module expandable pattern casting metal casting
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Approximate Well Width and Optical Gain Formulas of 1 .555μm In_(1-x-y )Ga_y Al_x As Compressively Strained Quantum- Well Laser 被引量:2
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作者 张冶金 陈维友 +2 位作者 蒋恒 刘彩霞 刘式墉 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2001年第1期11-17,共7页
Using Harrison's model and anisotropic parabolic approximation,the band structure of In1- x- y Gay Alx As compressively strained quantum wells is calculated.To design lasers with1.55μm wavelength,it is necessary... Using Harrison's model and anisotropic parabolic approximation,the band structure of In1- x- y Gay Alx As compressively strained quantum wells is calculated.To design lasers with1.55μm wavelength,it is necessary to an- alyze the well width,differential gain,transparency carrier density and the characteristic gain for an arbitrary com- position.Some useful empirical formulas are also presented. 展开更多
关键词 In1- x- y Gay alx as QW linear gain differential gai
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Effects of P2Y_1 receptor on glial fibrillary acidic protein and glial cell line-derived neurotrophic factor production of astrocytes under ischemic condition and the related signaling pathways 被引量:3
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作者 孙景军 刘颖 叶诸榕 《Neuroscience Bulletin》 SCIE CAS CSCD 2008年第4期231-243,共13页
Objective The present study aimed to explore the role of P2Y1 receptor in glial fibrillary acidic protein (GFAP) production and glial cell line-derived neurotrophic factor (GDNF) secretion of astrocytes under isch... Objective The present study aimed to explore the role of P2Y1 receptor in glial fibrillary acidic protein (GFAP) production and glial cell line-derived neurotrophic factor (GDNF) secretion of astrocytes under ischemic insult and the related signaling pathways. Methods Using transient right middle cerebral artery occlusion (tMCAO) and oxygen-glucose-serum deprivation for 2 h as the model of ischemic injury in vivo and in vitro, immunofluorescence, quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, enzyme linked immunosorbent assay (ELISA) were used to investigate location of P2Y1 receptor and GDNF, the expression of GFAP and GDNF, and the changes of signaling molecules. Results Blockage of P2Y1 receptor with the selective antagonist N^6-methyl-2′-deoxyadenosine 3′,5′-bisphosphate diammonium (MRS2179) reduced GFAP production and increased GDNF production in the antagonist group as compared with simple ischemic group both in vivo and in vitro. Oxygen-glucose-serum deprivation and blockage of P2Y1 receptor caused elevation of phosphorylated Akt and cAMP response element binding protein (CREB), and reduction of phosphorylated Janus kinase2 (JAK2) and signal transducer and activator of transcription3 (STAT3, Ser727). After blockage of P2Y1 receptor and deprivation of oxygen-glucose-serum, AG490 (inhibitor of JAK2) reduced phosphorylation of STAT3 (Ser727) as well as expression of GFAP; LY294002, an inhibitor of phosphatidylinositol 3-kinase (PI3-K), decreased phosphorylation of Akt and CREB; the inhibitor of mitogen-activated protein kinase kinase 1/2 (MEK 1/2) U0126, an important molecule of Ras/extracellular signal- regulated kinase (ERK) signaling pathway, decreased the phosphorylation of JAK2, STAT3 (Ser727), Akt and CREB. Conclusion These results suggest that P2Y1 receptor plays a role in the production of GFAP and GDNF in astrocytes under transient ischemic condition and the related signaling pathways may be JAK2/STAT3 and PI3-K/Akt/CREB, respectively, and that crosstalk probably exists between them. 展开更多
关键词 P2y1 receptor GLIOSIS glial fibrillary acidic protein glial cell line-derived neurotrophic factor PI3-K/akt/CREB JaK2/STaT3 Ras/ERK
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Effect of Y addition on microstructure and mechanical properties of Mg-Zn-Mn alloy 被引量:12
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作者 齐福刚 张丁非 +1 位作者 张孝华 潘复生 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第5期1352-1364,共13页
The effects of Y on the microstructure and mechanical properties of Mg-6Zn-lMn alloy were investigated. The results show that the addition of Y has significant effect on the phase composition, microstructure and mecha... The effects of Y on the microstructure and mechanical properties of Mg-6Zn-lMn alloy were investigated. The results show that the addition of Y has significant effect on the phase composition, microstructure and mechanical properties of Mg-6Zn-lMn alloy. Varied phases compositions, including Mg7Zn3, I-phase (Mg3YZn6), W-phase (Mg3Y2Zn3) and X-phase (MgI2YZn), are obtained by adjusting the Zn to Y mass ratio. Mn element exists as the fine Mn particles, which are well distributed in the alloy. Thermal analysis and microstructure observation reveal that the phase stability follows the trend of X〉W〉/〉MgTZn3. In addition, Y can improve the mechanical properties of Mg-Zn-Mn alloy significantly, and the alloy with Y content of 6.09% has the best mechanical properties. The high strength is mainly due to the strengthening by the grain size refinement, dispersion strengthening by fine Mn particles, and introduction of the Mg-Zn-Y ternary phases. 展开更多
关键词 Mg-Zn-Mn alloy y MICROSTRUCTURE mechanical property FRaCTURE
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Effects of Ce, Y and Gd additions on as-cast microstructure and mechanical properties of Mg-3Sn-2Sr magnesium alloy 被引量:5
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作者 杨明波 侯梦丹 +1 位作者 张佳 潘复生 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第8期2497-2506,共10页
The effects of Ce, Y and Gd additions on the as-cast microstructure and mechanical properties of Mg-3Sn-2Sr alloy were investigated and compared by scanning electron microscopy, X-ray diffraction, differential scannin... The effects of Ce, Y and Gd additions on the as-cast microstructure and mechanical properties of Mg-3Sn-2Sr alloy were investigated and compared by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry analysis, tensile and creep tests. The results indicate that the Mg-3Sn-2Sr ternary alloy is mainly composed ofα-Mg, primary and eutectic SrMgSn, and Mg2Sn phases. After the additions of 1.0%Ce, 1.0%Y and 1.0%Gd to the Mg-3Sn-2Sr alloy, the Mg12Ce, YMgSn, GdMgSn and/or Mg17Sr2 phases are formed, respectively. At the same time, the formation of the primary SrMgSn phase is suppressed and the coarse needle-like primary SrMgSn phase is modified and refined. In addition, the additions of 1.0% Ce, 1.0% Y and 1.0% Gd to the Mg-3Sn-2Sr alloy can simultaneously improve the tensile and creep properties of the alloy. Among the Ce-, Y-and Gd-containing alloys, the tensile properties of the Ce-containing alloy are relatively higher than those of the Y-and Gd-containing alloys. 展开更多
关键词 Mg-Sn-Sr alloys CE y GD SrMgSn phase
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Segregation and diffusion behavior of niobium in a highly alloyed nickel-base superalloy 被引量:3
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作者 潘晓林 于海燕 +2 位作者 涂赣峰 孙文儒 胡壮麒 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第11期2402-2407,共6页
The segregation during solidification and high temperature diffusion during homogenization of niobium in a highly alloyed nickel-base superalloy were investigated.Niobium is seriously segregated into the interdendriti... The segregation during solidification and high temperature diffusion during homogenization of niobium in a highly alloyed nickel-base superalloy were investigated.Niobium is seriously segregated into the interdendritic regions with segregation coefficient as high as 4.30.Various niobium-enriched phases including Laves phase,δ phase,(γ+γ') eutectic,MC and M6C types of carbides precipitated in the interdendritic regions.The soluble temperature of niobium-enriched phases and the degree of dendritic segregation were determined by differential thermal analysis and homogenization treatments at varied temperatures and times.The calculation of elemental diffusion indicates that the diffusion rate of niobium increases remarkably with the homogenization temperature increasing,so that the annealing time can be effectively reduced.A three-step homogenization treatment technology without incipient melting was established to eliminate the segregation of niobium and to obtain a uniform microstructure. 展开更多
关键词 GH742y superalloy NIOBIUM SEGREGaTION DIFFUSION
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Neuropeptide Y promotes TGF-β1 production in RAW264.7 cells by activating PI3K pathway via Y1 receptor 被引量:4
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作者 周江睿 徐拯 蒋春雷 《Neuroscience Bulletin》 SCIE CAS CSCD 2008年第3期155-159,共5页
Objective To examine the effect of neuropeptide Y (NPY) on TGF-β1 production in RAW264.7 macrophages. Methods Enzyme linked immunosorbent assay (ELISA) was used to detect TGF-β1 production. Cell counting kit 8 ... Objective To examine the effect of neuropeptide Y (NPY) on TGF-β1 production in RAW264.7 macrophages. Methods Enzyme linked immunosorbent assay (ELISA) was used to detect TGF-β1 production. Cell counting kit 8 (CCK-8) was used to assay the viability of RAW264.7 cells. Western blot was used to detect the phosphorylation of PI3K p85. Results NPY treatment could promote TGF-β1 production and rapid phosphorylation of PI3K p85 in RAW264.7 cells via Y1 receptor. The elevated TGF-β 1 production induced by NPY could be abolished by wortrnannin pretreatment. Conclusion NPY may elicit TGF-β production in RAW264.7 cells via Y1 receptor, and the activated PI3K pathway may account for this effect. 展开更多
关键词 neuropeptide y TGF-Β1 phosphoinositide-3 kinase RaW264.7 cells
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Effects of titanium on microstructure and mechanical properties of ZnAl4Y alloy 被引量:6
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作者 Wang Jianhua Wang Xiande +1 位作者 Tu Hao Su Xuping 《China Foundry》 SCIE CAS 2011年第4期397-400,共4页
The effect of Ti on the microstructure and mechanical properties of zinc-aluminum ZnAl4Y alloy has been investigated in this work. Small amount of Ti was added into ZnAl4Y alloy in the form of Al-10wt.%Ti alloy. The r... The effect of Ti on the microstructure and mechanical properties of zinc-aluminum ZnAl4Y alloy has been investigated in this work. Small amount of Ti was added into ZnAl4Y alloy in the form of Al-10wt.%Ti alloy. The results show that Ti addition into ZnAl4Y alloy refines the primary η-Zn phase and increases the amount of η-Zn + α-Al eutectic structure. There exists a ternary T phase in Zn-Al-Ti alloy. Fine TiAl3 particles and Ti-Zn compounds can serve as the nucleation sites of the α-Al and η-Zn phase, respectively, resulting in the refining of the microstructure of ZnAl4Y alloy. Ti addition changes the fracture characteristics of ZnAl4Y alloy. With 0.05wt%Ti, the fracture surface of the alloy shows a lot of dimples and tearing ridges connecting the microscopic dimples, which is mainly ductile fracture morphology. Ti addition into ZnAl4Y alloy also increases the mechanical properties of the alloy. When the content of Ti is 0.05wt.%, the ZnAl4Y alloy possesses the best comprehensive mechanical properties. 展开更多
关键词 TITaNIUM Znal4y alloy MICROSTRUCTURE mechanical properties
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Microstructure and corrosion behavior of as-homogenized and as-extruded Mg-xLi-3Al-2Zn-0.5Y alloys(x=4,8,12) 被引量:6
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作者 Xiang PENG Jia-wei SUN +2 位作者 Hong-jie LIU Guo-hua WU Wen-cai LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第1期134-146,共13页
The microstructure and corrosion behavior of the as-homogenized and as-extruded Mg-xLi-3Al-2Zn-0.5Y alloys(x=4,8,12,wt.%)were studied.The results show that as the Li content increases from 4%to 12%,the matrix transfer... The microstructure and corrosion behavior of the as-homogenized and as-extruded Mg-xLi-3Al-2Zn-0.5Y alloys(x=4,8,12,wt.%)were studied.The results show that as the Li content increases from 4%to 12%,the matrix transfers from singleα-Mg phase,(α-Mg+β-Li)dual phase to singleβ-Li phase.A mixed corrosion feature of intergranular corrosion and pitting corrosion occurs in the Mg-4Li-3Al-2Zn-0.5Y and Mg-12Li-3Al-2Zn-0.5Y alloys.The former is related to the precipitated AlLi phase along the grain boundaries,and the latter is related to the high potential difference between the second phase and the matrix.The corrosion resistance of the as-extruded alloys is better than that of the as-homogenized alloys.The superior corrosion resistance of the as-extruded Mg-8Li-3Al-2Zn-0.5Y alloy with the lowest corrosion rate(P_(W)=(0.63±0.26)mm/a)is attributed to the more uniform distribution of second phases,the protectiveα-Mg phase via sacrificing theβ-Li phase and the relatively integrated oxide film. 展开更多
关键词 Mg-xLi-3al-2Zn-0.5y alloys MICROSTRUCTURE corrosion behavior HOMOGENIZaTION extrusion second phase oxide film
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Growth morphology and evolution of quasicrystal in as-solidified Y-rich Mg-Zn-Y ternary alloys 被引量:4
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作者 WAN Diqing YANG Gencang CHEN Sulin ZHU Man ZHOU Yaohe 《Rare Metals》 SCIE EI CAS CSCD 2007年第5期435-439,共5页
A petal-like icosahedral quasicrystal with five branches,which is considered to be the representative morphology of the icosahedral quasicrystal,has been observed in the Y-rich Mg-Zn-Y ternary alloys. Moreover,the pol... A petal-like icosahedral quasicrystal with five branches,which is considered to be the representative morphology of the icosahedral quasicrystal,has been observed in the Y-rich Mg-Zn-Y ternary alloys. Moreover,the polygon-like morphology,another pattern of the icosahedral quasicrystal,has also been found in the Y-rich Mg-Zn-Y ternary alloys. The latter morphology results from the evolution of the former one. The growth mechanism of the petal-like morphology of the icosahedral quasicrystal was also discussed. Alloying composition,i.e.,Y element content,is a major factor inducing the morphology evolution of the icosahedral quasicrystal. 展开更多
关键词 Mg-Zn-y ternary alloys icosahedral quasicrystal morphology evolution y element
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MICROSTRUCTURES AND PROPERTIES OF RECIPROCATINGLY EXTRUDED Mg-6.4Zn-1.1Y ALLOYS 被引量:3
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作者 Z.M. Zhang C.J. Xu X.F. Guo 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2008年第1期37-42,共6页
An icosahedral Mg3 YZn6 quasicrystalline phase can be produced in Mg-Zn- Y system alloys when a proper amount of Zn and Y is contained, and it is feasible to prepare the quasicrystal phase-reinforced low-density magne... An icosahedral Mg3 YZn6 quasicrystalline phase can be produced in Mg-Zn- Y system alloys when a proper amount of Zn and Y is contained, and it is feasible to prepare the quasicrystal phase-reinforced low-density magnesium alloy. In this article, phase constituents and the effect of reciprocating extrusion on microstructures and properties of the as-cast Mg-6.4Zn-1.1 Y alloy are analyzed. The microstructure of the as-cast Mg-6.4Zn-1.1 Y alloy consists of the α-Mg solid solution, icosahedral Mg3YZn6 quasicrystal, and Mg3 Y2Zn3 and MgZn2 compounds. After the alloy was reciprocatingly extruded for four passes, grains were refined, Mg3 Y2 Zn3 and MgZn2 phases dissolved into the matrix, whereas, Mg3 YZn6 precipitated and distributed uniformly. The alloy possesses the best performance at this state; the tensile strength, yield strength, and elongation are 323.4 MPa, 258.2 MPa, and 19.7%, respectively. In comparison with that of the as-cast alloy, the tensile strength, yield strength, and elongation of the reciprocatingly extruded alloy increase by 258.3%, 397.5%, and 18 times, respectively. It is concluded that reciprocating extrusion can substantially improve the properties of the as-cast Mg-6.4Zn-1.1 Y alloy, particularly for elongation. The high performance of the Mg-6.4Zn-1.1 Y alloy after reciprocating extrusion can be attributed to dispersion strengthening and grain-refined microstructures. 展开更多
关键词 Reciprocating extrusion Mg-Zn- y alloy Icosahedral quasicrystal
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Hot tearing susceptibility of Mg-xZn-2Y alloys 被引量:3
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作者 Zhi WANG Yi-zhou LI +4 位作者 Feng WANG Yuan-ding HUANG Jiang-feng SONG Ping-li MAO Zheng LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第12期3115-3122,共8页
Effects of Zn content (0, 0.5%, 1.5% and 4.5%) on the hot tearing characteristics of Mg?2%Y alloy were studied in aconstrained rod casting (CRC) apparatus attached with a load cell and data acquisition system. The exp... Effects of Zn content (0, 0.5%, 1.5% and 4.5%) on the hot tearing characteristics of Mg?2%Y alloy were studied in aconstrained rod casting (CRC) apparatus attached with a load cell and data acquisition system. The experimental results indicate thatthe hot tearing susceptibility (HTS) is affected by the content of Zn. The Zn-free base alloy shows the lowest HTS. The HTS ofMg?xZn?2Y alloys increases with increasing Zn content, reaches the maximum at 1.5% Zn, and then decreases with further Znaddition. The high HTS observed in the alloy with 1.5% Zn is attributed to its high force release rate and large force drop duringsolidification. The hot cracks of casting are initiated and propagate along the dendritic or grain boundaries. The predictions of HTS ofMg?xZn?2Y alloys using ProCAST software are in good agreement with the results obtained by experimental measurements. 展开更多
关键词 Mg-xZn-2y alloy hot tearing susceptibility solidification contraction force numerical simulation
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Expression of Neuropeptide Y in Human Pituitary Adenoma 被引量:3
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作者 Laizhao Chen Jingjian Ma +1 位作者 Anchao Zheng Honggang Zheng 《Chinese Journal of Clinical Oncology》 CSCD 2006年第1期25-31,共7页
OBJECTIVE Neuropeptide Y (NPY) acts as a neuroendocrine modulator in the anterior pituitary, and NPY mRNA and NPY-immunoreactivity have been detected in normal human anterior pituitaries. However, only a few studies... OBJECTIVE Neuropeptide Y (NPY) acts as a neuroendocrine modulator in the anterior pituitary, and NPY mRNA and NPY-immunoreactivity have been detected in normal human anterior pituitaries. However, only a few studies of NPY expression in human pituitary adenomas have been published. Our study was conducted to determine whether or not adenomatous cells express NPY, to investigate the relationship between NPY expression and the subtypes of pituitary adenoma and to explore the clinical significance of NPY. METHODS The study included tissues from 58 patients with pituitary adenomas who underwent surgery because of their clinical diagnosis. Using a highly specific anti-NPY polyclonal antibody, immunohistochemical analysis was performed on the surgically removed pituitary adenomas. Six fresh specimens also were examined using immuno-electron microscopy. NPY was labeled with colloidal gold in order to study the distribution of NPY at the subcellular level. RESULTS The NPY expression level was significantly different among subgroups of pituitary adenomas (P〈0.05). NPY was immuno-detected in 58.6% of all adenomas, in 91.7% of gonadotrophic adenomas and in 14.3% of prolactinomas. NPY expression was slightly lower in invasive pituitary adenomas compared to noninvasive adenomas, but the difference was not significant (t=1.81, P〉0.05). Of particular interest was the finding that vascular endothelial cells showed positive NPY expression in some pituitary adenomas. Parts of strongly positive tumor cells were seen in channels formed without endothelial cells, but which contained some red blood cells in a formation similar to so-called vasculogenic mimicry. Immuno-electron microscopy demonstrated that 4 of the 6 fresh specimens displayed positive NPY staining with a high density of gold particles located mainly in the secretory granulas. In addition, gold particles were sparsely detected in the rough endoplasmic reticulum and cell matrix. CONCLUSION NPY exists in pituitary adenomas and its expression level was related to the types and biological characteristics of the pituitary adenomas. NPY may have a depressive effect on tumor cellular proliferation in pituitary adenomas. NPY possibly participates in modulating angiogenesis and hemodynamic changes in pituitary adenomas. 展开更多
关键词 neuropeptide y pituitary adenoma IMMUNOHISTOCHEMISTRy immuno-electron microscopy.
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Effect of bonding temperature and heat treatment on microstructure and mechanical property of Mg−6Gd−3Y alloy vacuum diffusion bonded joints 被引量:2
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作者 Ping-yi MA Xu CHEN +2 位作者 Xing HAN Zhi-qiang LUO He-li PENG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第7期2205-2215,共11页
Diffusion bonding of as-cast Mg−6Gd−3Y magnesium alloy was carried out at temperatures of 400−480℃ with bonding pressure of 6 MPa for 90 min.Diffusion bonded joints were solution treated at 495℃ for 14 h and then ag... Diffusion bonding of as-cast Mg−6Gd−3Y magnesium alloy was carried out at temperatures of 400−480℃ with bonding pressure of 6 MPa for 90 min.Diffusion bonded joints were solution treated at 495℃ for 14 h and then aged at 200℃ for 30 h.Microstructures and mechanical properties of joints were analyzed.The results showed that rare earth elements and their compounds gathering at bonding interface hindered the grain boundary migration crossing bonding interface.Tensile strength of as-bonded and as-solution treated joints increased firstly and then decreased with the bonding temperature increasing due to the combined effects of grain coarsening and solid-solution strengthening.As-bonded and solution-treated joints fractured at matrix except the joint bonded at 400℃,while aged joints fractured at bonding interface.The highest ultimate tensile strength of 279 MPa with elongation of 2.8%was found in joint bonded at 440℃ with solution treatment followed by aging treatment. 展开更多
关键词 Mg−Gd−y alloy vacuum diffusion bonding post-weld heat treatment bonding interface bonding strength
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The effect of traditional Chinese medicine──Tian Gui Recipeon obesity and anovulation in androgen-sterilized rats 被引量:7
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作者 俞瑾 孙斐 《生殖医学杂志》 CAS 2000年第S1期26-33,共8页
Objective: A traditional Chinese medicine Tian Gui Recipe (TGR) has been used to effectively treat clomiphene resistant anovulatory disease and obesity, especially in polycystic ovary syndrome (PCOS) cases with hyperi... Objective: A traditional Chinese medicine Tian Gui Recipe (TGR) has been used to effectively treat clomiphene resistant anovulatory disease and obesity, especially in polycystic ovary syndrome (PCOS) cases with hyperinsulinemia. The effect of TGR on obesity and anovulation was investigated in androgen-sterilized rats (ASR). Methods: Female SD rats at the age of 9 days were divided into 3 groups. Group ASR (n=15): anovulation was demonstrated at the age of 70 days by vaginal smear in rats while 1. 25 mg of testosterone propionate was injected subcutaneously on its 9th neonatal day. Group A+H (n = 25): TGR were administered to ASR at the age of 80 days for 3 weeks. Rats with regular estrous cycle and ovulation after herbal treatment were included in this group. Group C (n = 15): normal ovulated rats were recruited. Around the age of 112 days or on proestrous day, all rats were sacrificed under anesthesia. Serum leptin, testosterone (T), estrogen (E2), follicular stimulating hormone (FSH), luteinizing hormone (LH) levels were measured with radioimmunoassay (RIA). Double immunofluorescent staining combined with confocal laser scanning microscope and dual in situ hybridization were carried out on sections through areas of arcuate nucleus (ARC) to determine whether estrogen receptor (ER) immunoreactivity (IR) or long form of leptin receptor (OB-Rb) mRNA were expressed in neuropeptide Y (NPY) immuno-and mRNA-containing neurons, and its relationship to proopiomelanocortin (POMC) mRNA-containing neurons. Immunohistochemistry and in situ hybridization were used to observe the levels of ER, NPY, gonadotrophin releasing hormone (GnRH) and gene expression levels on NPY, OB-Rb, POMC. Meanwhile, the criteria of energy state, including daily food intake, retroperitoneal fat depot pad and body weight, were measured and evaluated. Values of immunohistochemistry and in situ hybridization were expressed in mean optic density (MOD). Results: Seventeen out of the 25 rats (68%) in Group A+H were ovulated after herbal treatment. ASR characterized with significantly high metabolic rate, energy imbalance and obesity (P<0. 01, P<0. 01, P<0. 01). The mean serum leptin, T, E2 levels of group ASR were significantly higher than those of Group C and Group A+H (P< 0. 01,P<0. 01 ), while FSH, LH levels were lower (P<0. 01, P<0. 01 ). ERs were proved to be distributing in NPY-containing neurons, OB-Rb coexpressed in NPY-syn- thesizing neurons, and both NPY and POMC mRNA expressing neurons overlapped in ARC. Compared to Group C, levels of NPY mRNA and NPY, POMC mRNA expressions were increased (P<0. 01, P<0. 01, P<0. 01 ), OB-Rb mRNA, ER and GnRH immunoreactive expression were decreased significantly in the hypothalamus of ASR (P<0. 01, P<0. 01, P<0. 01 ). These dramatic neuroendocrine changes became normal in ovulated ASR after the herbal treatment (all P>0. 05). Conclusion: The elevated peripheral E2 caused by high T and leptin levels in ASR may down-regulate their corresponding receptors oriented on hypothalamic NPY- containing neurons respectively, therefore challenge the NPY mRNA and NPY, POMC mRNA overexpressions. The overexpression, of NPY, POMC gene transcription and translation stimulate food intake, promote the deposit of adipocyte tissue, and inhibit GnRH expression and GnRH/FSH, LH release, which contribute to the occurrence of obesity and anovulation in ASR. TGR may reverse these abnormal neuroendocrine cascades by lowering the levels of T, E2 and leptin. 展开更多
关键词 androgen-sterilized rat Traditional Chinese medicine Neuropeptide y Leptin PROOPIOMELaNOCORTIN ESTROGEN Gonadotrophin releasing hormone Immunohistochemistry In situ hybridization mRNa This work was supported by a grant from the Planni
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Microstructural evolution and mechanical performance of cast Mg−3Nd−0.2Zn−0.5Zr alloy with Y additions 被引量:2
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作者 He XIE Guo-hua WU +4 位作者 Xiao-long ZHANG Zhong-quan LI Wen-cai LIU Liang ZHANG Bao-de SUN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第10期3222-3237,共16页
This work investigated the effects of different Y additions(0,1.5,3.0 and 4.5 wt.%)on the microstructural evolution and mechanical performance of cast Mg−3Nd−0.2Zn−0.5Zr alloy.The results show that as the Y content in... This work investigated the effects of different Y additions(0,1.5,3.0 and 4.5 wt.%)on the microstructural evolution and mechanical performance of cast Mg−3Nd−0.2Zn−0.5Zr alloy.The results show that as the Y content increases,the key secondary phases in as-cast alloys change from the Mg_(12)Nd type to the Mg_(24)Y_(5) type.Meanwhile,the number density of Zn−Zr particles in the grains of as-quenched alloys gradually decreases.HAADF-STEM observations of peak-aged samples reveal that element Y is greatly enriched in the globularβ¢precipitates,leading to a significantly increased volume fraction and promoted precipitation kinetics ofβ¢precipitates,resulting in enhanced strength of the alloy.Tensile tests reveal that,with the addition of 4.5 wt.%Y,the yield strength of the base alloy is substantially increased by 88 and 61 MPa after being aged at 200 and 225°C under peak-aged conditions,respectively. 展开更多
关键词 Mg−3Nd−0.2Zn−0.5Zr alloy y alloying age-hardening response microstructural evolution mechanical properties
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Corrosion behaviour of as-cast ZK40 with CaO and Y additions 被引量:1
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作者 Ricardo Henrique BUZOLIN Marta MOHEDANO +6 位作者 Chamini Lakshi MENDIS Beatriz MINGO Domonkos TOLNAI Carsten BLAWERT Karl Ulrich KAINER Haroldo PINTO Norbert HORT 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第3期427-439,共13页
The microstructures of as-cast ZK40,ZK40 with 2%(mass fraction)CaO and ZK40 with 1%(mass fraction)Y were investigated,and the intermetallic phase morphology and the distribution were characterised.By having discrete i... The microstructures of as-cast ZK40,ZK40 with 2%(mass fraction)CaO and ZK40 with 1%(mass fraction)Y were investigated,and the intermetallic phase morphology and the distribution were characterised.By having discrete intermetallic particles at the grain boundaries for the ZK40,the microstructure was modified to a semi-continuous network of intermetallic compounds along the grain boundaries for the ZK40 with CaO or Y additions.The CaO was not found in the microstructure.However,Ca was present in Ca2Mg6Zn3 intermetallic compounds which were formed during casting.Hydrogen evolution and electrochemical impedance spectroscopy tests revealed that the addition of CaO slightly enhanced the corrosion resistance whereas Y had a negative effect on the corrosion resistance of ZK40.Immersion tests showed that severe localised corrosion as well as corrosion along the intermetallic compounds played an important role in the corrosion process of ZK40-Y whereas the localised corrosion was not pronounced for ZK40 or ZK40?CaO alloys.Micro-segregation in theα-Mg matrix was notably higher for the ZK40 alloy compared with the modified alloys.The combination of this effect with a possible formation of a more stable corrosion layer for the ZK40-CaO was attributed as the main reason for an improved corrosion resistance for the ZK40-CaO alloy. 展开更多
关键词 Mg alloy ZK40 y addition CaO addition corrosion behaviour
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