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Structure,room-temperature magnetic and optical properties of Mn-doped TiO_2 nano powders prepared by the sol-gel process
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作者 丁芃 刘发民 +4 位作者 周传仓 钟文武 张嬛 蔡鲁刚 曾乐贵 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第11期667-672,共6页
TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process, and were annealed at 500 ℃ and 800 ℃ in air for 2 hrs. X-ray diffraction (XRD) measurements indicate that the Mn-TiO... TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process, and were annealed at 500 ℃ and 800 ℃ in air for 2 hrs. X-ray diffraction (XRD) measurements indicate that the Mn-TiO2 nano powders with Mn concentration of 1 at% and 2 at% annealed at 500 and 800 ℃ are of pure anatase and rutile, respectively. The scanning electron microscope (SEM) observations reveal that the crystal grain size increases with the annealing temperature, and the high resolution transmission electron microscopy (HRTEM) investigations further indicate that the samples are well crystallized, confirming that Mn has doped into the TiO2 crystal lattice effectively. The room temperature ferromagnetism, which could be explained within the scope of the bound magnetic polaron (BMP) theory, is detected in the Mn-TiO2 samples with Mn concentration of 2 at%, and the magnetization of the powders annealed at 500 ℃ is stronger than that of the sample treated at 800 ℃. The UV-VIS diffuse reflectance spectra results demonstrate that the absorption of the TiO2 powders could be enlarged by the enhanced trapped electron absorption caused by Mn doping. 展开更多
关键词 mn-doped TiO2 nano powders sol-gel process room-temperature magnetic properties diffuse reflectance spectra
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Sonochemical synthesis,characterization,and magnetic properties of Mn-doped ZnO nanostructures
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作者 Nuengruethai Ekthammathat Anukorn Phuruangrat +5 位作者 Thirawit Phonkhokkong Wachiraporn Maisang Patcharanan Junploy Arrak Klinbumrung Somchai Thongtem Titipun Thongtem 《Rare Metals》 SCIE EI CAS CSCD 2021年第12期3561-3566,共6页
Mn-doped ZnO samples,Zn_(1-x)Mn_(x)O(x=0,0.01,0.03 and 0.05;mole fraction),were successfully synthesized by sonochemical method.The undoped and Mn-doped Zn O samples were characterized by X-ray diffraction(XRD),scanni... Mn-doped ZnO samples,Zn_(1-x)Mn_(x)O(x=0,0.01,0.03 and 0.05;mole fraction),were successfully synthesized by sonochemical method.The undoped and Mn-doped Zn O samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and Raman spectroscopy.XRD patterns of all products are identified to hexagonal wurtzite Zn O structure and their three main peaks shift toward lower diffraction angles due to the incorporation of Mn^(2+)into Zn O crystal lattice.The morphologies of Zn_(1-x)Mn_(x)O(x=0,0.01,0.03 and 0.05)were examined by SEM and TEM.The undoped Zn O sample shows large-scale uniform microflowers which are broken into nanorods and nanoparticles by Mn dopant.Their magnetic properties were investigated by a vibrating sample magnetometer at room temperature.The magnetization-applied field behavior of undoped Zn O defines its weak ferromagnetic behavior.The 3 mol%Mn-doped Zn O shows the highest saturation magnetization of 51.73910^(-3)m A·m^(2)·g^(-1),and the 5 mol%Mn-doped Zn O has suppressed ferromagnetic property due to the formation of Mn clusters inside. 展开更多
关键词 mn-doped ZnO XRD Electron microscopy Raman spectroscopy magnetic properties
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层状前体法制备锰掺杂钴铁氧体的性能 被引量:1
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作者 周小多 祁欣(指导) 李峰 《机械工程材料》 CAS CSCD 北大核心 2009年第7期87-90,共4页
采用层状前体法制备了锰掺杂钴铁氧体Co1-xMnxFe2O4(x分别取0.1,0.2,0.3,0.4),用X射线衍射仪分析了它的物相与结构,用振动样品磁强计测试了它的磁性能,采用自制设备研究了其对巴克豪森信号的接收特性。结果表明:该铁氧体均以单相尖晶石... 采用层状前体法制备了锰掺杂钴铁氧体Co1-xMnxFe2O4(x分别取0.1,0.2,0.3,0.4),用X射线衍射仪分析了它的物相与结构,用振动样品磁强计测试了它的磁性能,采用自制设备研究了其对巴克豪森信号的接收特性。结果表明:该铁氧体均以单相尖晶石结构存在;掺锰降低了材料的矫顽力,且锰含量越大,矫顽力越小;当x=0.1时材料的饱和磁化强度比钴铁氧体的要大,之后其值随锰含量的增加逐渐减小;Co1-xMnxFe2O4尖晶石铁氧体材料有望作为接收器件应用于巴克豪森磁弹传感器。 展开更多
关键词 层状前体 锰掺杂 磁性能 接收特性
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3.0T MRI评价脑白质高信号患者拓扑属性改变与认知功能的关系及预测意义
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作者 杨春 付成伟 《临床误诊误治》 CAS 2023年第9期89-94,107,共7页
目的 探究3.0T MRI评价脑白质高信号(WMH)患者拓扑属性改变与认知功能的关系及预测价值。方法 选取2019年8月—2022年8月95例WMH作为研究组,另选同期95例无WMH志愿者作为对照组。比较2组脑体积数据[深部脑白质高信号(DWMH)、室周脑白质... 目的 探究3.0T MRI评价脑白质高信号(WMH)患者拓扑属性改变与认知功能的关系及预测价值。方法 选取2019年8月—2022年8月95例WMH作为研究组,另选同期95例无WMH志愿者作为对照组。比较2组脑体积数据[深部脑白质高信号(DWMH)、室周脑白质高信号(PWMH)、总脑白质高信号(TWMH)]、脑白质网络拓扑全局属性指标[聚类系数、最短路径长度、全局效率、局部效率、“小世界”网络属性(γ、λ、δ)],分析拓扑全局属性指标与脑体积数据、病情程度、认知功能的相关性,受试者工作特征曲线评价拓扑全局属性指标预测WMH患者合并认知功能障碍的价值。结果 研究组DWMH体积、PWMH体积、TWMH体积、最短路径长度、γ、δ均高于对照组,全局效率、局部效率均低于对照组(P<0.01)。最短路径长度、γ、δ分别与DWMH体积、PWMH体积、TWMH体积、病情程度、认知功能呈正相关,局部效率、全局效率分别与DWMH体积、PWMH体积、TWMH体积、病情程度、认知功能呈负相关(P<0.01)。最短路径长度、全局效率、局部效率、γ、δ联合预测WMH合并认知功能障碍的曲线下面积为0.940,大于各指标单独预测的曲线下面积(P<0.05,P<0.01)。结论 3.0T MRI评价拓扑属性改变可用于评估WMH患者的病情程度及认知功能,临床可通过其早期预测WMH并发认知功能障碍,以针对性治疗,改善预后。 展开更多
关键词 脑白质高信号 大脑小血管疾病 磁共振成像 拓扑属性 认知障碍 脑网络 预测价值 受试者工作特征曲线
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