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Influence of A-site doping barium on structure,magnetic and microwave absorption properties of LaFeO_(3)ceramics powders

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Journal of Rare Earths 2022年第7期40卷 1106-1117页

作者： Lei Huang lichun cheng Shunkang Pan Qingrong Yao Qianxin Long Man Wang Yucheng Chen Huaiying Zhou School of Materials Science and Engineering Guilin University of Electronic TechnologyGuilin 541004China Guangxi Key Laboratory of Information Materials Guilin University of Electronic TechnologyGuilin 541004China

In this paper,the effect of Ba^(2+)ions A-site doping LaFeO_(3)on structure,magnetic properties and microwave absorption properties was investigated by the sol-gel method.According to the TEM and FullProf refinement results,the structure of LaFeO_(3)changes from orthogonal(SG:Pnma)to cubic(SG:Pm-3 m)when the Ba doping amount is x=0.4.The SEM image shows that the particles size tends to decrease with the increase of Ba content.The production of weak ferromagnetism indicates that Ba doping has a significant effect on the magnetic properties of LaFeO_(3).The Neel temperature(TN)decreases significantly with the increase of Ba doping amount.An appropriate amount of Ba doping can effectively increase the dielectric and magnetic loss of LaFeO_(3)ceramics powders.The increase permittivity(ε’andε″)may be attributed to the hopping of the electrons between the Fe^(3+)and Fe^(4+)ions with the Ba^(2+)ions doping.The minimum reflection loss(RL_(min))of La_(0.9)Ba_(0.1)FeO_(3)at 6.72 GHz reaches-30.04 dB,its effective bandwidth(RL≤-10 dB)is 2.1 GHz,and the matching thickness is only 3.2 mm.These results indicate that Ba doping can effectively control the microwave absorption properties of LaFeO_(3),especially in the Cband.

关键词： LaFeO_(3)ceramics Crystal structure Magnetic Electromagnetic parameters Microwave absorption Rare earths

Electromagnetic and microwave absorption properties of Er-Ho-Fe alloys

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Journal of Rare Earths 2018年第7期36卷 715-720页

作者： Jialiang Luo Shunkang Pan lichun cheng Peihao Lin Yu He Junqing Chang School of Materials Science and Engineering Guilin University of Electronic Technology Guangxi Key Laboratory of Information Materials Guilin University of Electronic Technology School of Materials Science and Engineering Central South University

The ErxHo（2-x）Fe（17）（x = 0.0, 0.1,0.2, 0.3, 0.4） powders were prepared by arc melting and high energy ball milling method. The influence of the Er substitution on phase structure, morphology, saturation magnetization,electromagnetic parameters was investigated by X-ray diffraction（XRD）,scanning electron microscopy（SEM）, vibrating sample magnetometer（VSM） and vector network analyzer（VNA）,respectively. The results show that the saturation magnetization increases and the average particle size increases with the increase of Er content. The minimum absorption peak frequency shifts towards a lower frequency region with the increase of Er content. The ErxHo2-xFe17 powder can achieve the minimum RL of-24.07 dB at 6.96 GHz with a thickness of 2.0 mm and the minimum RL is less than-20 dB at the thickness range from 2.0 to 3.0 mm. The minimum RL of ErxHo2-xFe17 is-37.26 dB at5.68 GHz and the frequency bandwidth of R〈-10 dB reaches about 1.2 GHz with a thickness of 2.4 mm.And the microwave absorbing properties of the composite with different weight ratios of Er0.3Ho1.7Fe17/graphene were researched. The microwave absorbing peaks of the composite shift to lower frequency with the increase of graphene content. The values of the minimum RL of ErxHo2-xFe17/graphene are close to-10 dB with absorbing coating thicknesses increased.

关键词： ErxHo2-xFe17 alloys Reflection loss Electromagnetic parameters Magnetic properties Microwave absorbing properties Rare earths

miR-152-3p表达下调降低紫杉醇耐药人卵巢癌细胞A2780T对紫杉醇的耐药性

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中国药理学与毒理学杂志 2024年第1期38卷 22-30页

作者：张洋赵辰戈程荔春吕慧怡吴迪大连医科大学附属第二医院药学部辽宁大连116023 大连医科大学药学院辽宁大连116044 大连科翔生物科技有限公司辽宁大连116085

目的探讨miR-152-3p对紫杉醇耐药人卵巢癌细胞A2780T对紫杉醇耐药性的影响及机制。方法①紫杉醇(1.875,3.75,7.5,17和23μmol·L^(-1))与人卵巢癌A2780和A2780T细胞作用48 h,MTT法检测细胞存活率,计算抑制细胞存活半数抑制浓度(IC50)值... 详细信息

目的探讨miR-152-3p对紫杉醇耐药人卵巢癌细胞A2780T对紫杉醇耐药性的影响及机制。方法①紫杉醇(1.875,3.75,7.5,17和23μmol·L^(-1))与人卵巢癌A2780和A2780T细胞作用48 h,MTT法检测细胞存活率,计算抑制细胞存活半数抑制浓度(IC50)值和耐药指数(RI)。Western印迹法检测A2780和A2780T细胞耐药蛋白P-糖蛋白(P-gp)、多药耐药相关蛋白1(MRP1)和三磷酸腺苷结合转运蛋白G超家族成员2(ABCG2)蛋白表达。②实时荧光定量PCR(RT-qPCR)检测A2780和A2780T细胞miR-152-3p表达水平。脂质体瞬时转染技术转染miR-152-3p抑制物降低A2780T细胞中miR-152-3p表达(miR-152-3p抑制物组),同时设转染miR-152-3p阴性对照组,RT-qPCR检测转染效率,MTT法、划痕实验和流式细胞术分别检测转染miR-152-3p抑制物对A2780T细胞存活、迁移和凋亡的影响;Western印迹法检测转染miR-152-3p抑制物对A2780T细胞Bax和Bcl-2蛋白表达的影响。③用miRDB,Targetscan,miRWalk和Starbase数据库预测miR-152-3p的靶基因,并用Western印迹法检测转染miR-152-3p抑制物后A2780T细胞磷酸酯酶张力蛋白同源物(PTEN)蛋白表达的变化及RT-qPCR检测A2780和A2780T细胞PTEN mRNA表达水平予以验证。随后,脂质体瞬时转染技术转染PTEN siRNA沉默A2780T细胞中PTEN表达,同时设转染siRNA阴性对照组,RT-qPCR检测转染效率,MTT法检测沉默PTEN表达后A2780T细胞存活率和IC50值,Western印迹法检测P-gp,MRP1和ABCG2蛋白表达。结果①紫杉醇处理后A2780和A2780T细胞存活率均降低(P<0.01),A2780T细胞RI为2.8。与A2780细胞相比,A2780T细胞P-gp,MRP1和ABCG2蛋白高表达(P<0.05,P<0.01)。②与A2780细胞相比,A2780T细胞miR-152-3p明显高表达(P<0.01)。与转染miR-152-3p阴性对照组比较,转染miR-152-3p抑制物后A2780T细胞存活率(P<0.05,P<0.01)和细胞迁移能力(P<0.05)明显降低,细胞凋亡率升高(P<0.01);Bax蛋白表达增加(P<0.01),Bcl-2蛋白表达降低(P<0.05)。③生物信息学数据库分析结果提示,PTEN是miR-152-3p的一个靶基因;Western印迹法验证显示,转染miR-152-3p抑制物组A2780T细胞PTEN蛋白表达低于转染miR-152-3p阴性对照组(P<0.05);RT-qPCR结果显示,A2780T细胞PTEN mRNA表达水平高于A2780细胞(P<0.01)。转染PTEN siRNA沉默PTEN表达后,与转染siRNA阴性对照组相比,A2780T细胞存活率(P<0.05,P<0.01)和IC50值(P<0.01)显著降低,P-gp,MRP1和ABCG2蛋白表达降低(P<0.05,P<0.01)。结论miR-152-3p在A2780T细胞中高表达,其表达下调可抑制A2780T细胞增殖和迁移,促进细胞凋亡,降低A2780T细胞对紫杉醇的耐药性,该作用可能是通过降低其靶基因PTEN表达发挥的。

关键词：卵巢癌 miR-152-3p 紫杉醇耐药细胞增殖细胞凋亡

Deformation dependence of symmetry energy coefficients of nuclei

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Science China(Physics,Mechanics & Astronomy) 2015年第8期58卷 33-38页

作者： MO QiuHong LIU Min cheng lichun WANG Ning Department of Physics Guangxi Normal University School of Material Science and Engineering Guilin University of Electronic Technology

Based on the semi-classical Thomas-Fermi approximation together with the Skyrme energy-density functional, we study the deformation dependence of symmetry energy coefficients of finite nuclei. The symmetry energy coefficients of nuclei with mass number A = 40, 100, 150, 208 are extracted from two-parameter parabola fitting to the calculated energy per particle. We find that the symmetry energy coefficients decrease with the increase of nuclear quadrupole deformations, which is mainly due to the isospin dependence of the difference between the proton and neutron surface diffuseness. Large deformations of nuclei can cause the change of the symmetry energy coefficient by about 0.5 Me V and the influence of nuclear deformations on the symmetry energy coefficients is more evident for light and intermediate nuclei.

关键词：对称能原子核大变形能量密度抛物线拟合托马斯依赖性有限核

Microwave Absorbing Performance of RE-Fe Based Alloys

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Journal of Wuhan University of Technology(Materials Science) 2015年第3期30卷 607-610页

作者：刘星 PAN Shunkang cheng lichun 饶光辉 LIN Peihao Guangxi Key Laboratory of Information Materials Guilin University of Electronic Science and Technology

REI3Fes4Cr3（RE=Ce, Pr, Tb, Er） and Pr13_XFes4Cr3Ti（x=0, 2, 4, 6） alloy powders were prepared by are smelting method and high energy ball milling technique. The phase structure and the morphology of the alloy powders were investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM）, and their microwave absorbing properties were determined by a vector network analyzer. The results show that the alloys with light rare earths （Ce, Pr） have good low frequency absorbing property and those with heavy rare earths （Tb, Er） exhibit an improved high frequency absorbing property. The minimum refleetivity at the absorbing peak frequency of RE,FeuCr3（RE=Ce, Pr, Tb, Er） are -9.49 dB at 5.76 GHz, -22.38 dB at 7.92 GHz, -18.52 dB at 11.68 GHz and -17.59 dB at 10.24 GHz, respectively. The absorbing bandwidth under -10 dB of the Pr13FesaCr3 powder was widened from 1.91 GI-Iz to 3.89 GHz by adding 2% Ti, but the reflectivity of the alloy was increased from -22.38 dB to -14.91 riB.

关键词： RE-Fe based alloys microwave absorbing property reflectivity electromagneticparameter high energy ball milling

课程学习经历提升青少年社会参与素养:链式中介效应

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心理科学 2022年第2期45卷 323-330页

作者：张畅丁玉婷程立春陈宁上海师范大学心理系上海200234 上海市奉贤区曙光中学上海201411

运用基于学校的研究范式,以上海市某中学为样本学校,考察社会参与特色课程学习经历对青少年社会参与素养的影响机制。结果显示:(1)修学的特色课程门数(量)、情感体验(质)、公共服务动机和社会参与素养两两显著正相关;(2)情感体验和公共... 详细信息

运用基于学校的研究范式,以上海市某中学为样本学校,考察社会参与特色课程学习经历对青少年社会参与素养的影响机制。结果显示:(1)修学的特色课程门数(量)、情感体验(质)、公共服务动机和社会参与素养两两显著正相关;(2)情感体验和公共服务动机在课程学习数量和社会参与素养间发挥部分中介作用;(3)未发现基础课程成绩在链式中介中起调节作用。研究为通过加强课程情感体验进而提升青少年核心素养提供了积极启示。

关键词：社会参与素养课程学习经历情感体验公共服务动机基于学校的研究

Effect of rare earths on microwave absorbing properties of RE-Co alloys

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Journal of Rare Earths 2015年第3期33卷 271-276页

作者：何崇康潘顺康成丽春刘星吴亚军 School of Materials Science and Engineering Guilin University of Electronic Technology Hezhou Science and Technology Bureau School of Materials Science and Engineering Central South University

The powders of RE2Co17（RE=Y, Ce, Nd, Ho, Er） and Ho x Co100–x（x=6, 8, 10, 12） alloys were prepared by the arc melting method and high-energy ball mill process. The compositions and morphologies of the alloys were characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM）, and the microwave absorbing properties were studied by a vector network analyzer. The results showed that the alloy of Y2Co17 had better absorbing properties at low frequencies and its lowest reflectivity value was –9.5 d B at 3.8 GHz. The lowest reflectivity value of Ho2Co17 alloy was –13.7 d B at 7.02 GHz and it obtained large absorbing bandwidth. Reflectivity value less than –5 d B was from 5.1 to 10.2 GHz. When x=6 and x=8, the alloys of Ho x Co100–x consisted of Ho2Co17 phase and Co phase. They had good radar absorbing properties. With increase in Ho content, the minimum reflectivity value worsened and the absorbing peak frequency shifted toward higher frequencies. But when x=12, the absorbing peak frequency shifted toward lower frequencies but the minimum reflectivity value worsened.

关键词： RE2Co17 alloy microwave absorbing properties high energy ball milling Ho content rare earths

Effects of cobalt substitution on structure and microwave absorption properties of PrNi_5 alloy

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Journal of Rare Earths 2015年第12期33卷 1324-1328页

作者：潘顺康熊吉磊成丽春姚青荣饶光辉 School of Material Science and Engineering Guilin University of Electronic Technology Guangxi Key Laboratory of Information Materials Guilin University of Electronic Technology School of Materials Science and Engineering Central South University

The polycrystalline samples PrNi5_xCox （x=0.0, 0.1, 0.2, 0.3, 0.4） were synthesized by arc smelting and high energy ball milling method. The phase structure, morphology, saturation magnetization and electromagnetic parameters of the alloy powders were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, vibrating sample magnetomctry （VSM） and vector network analyzer （VNA）, respectively. The results revealed that the lattice parameter a and c and unit-cell volume V increased with the increasing amount of Co substitution. The saturation magnetization increased as Co content increased. The minimum absorp- tion peak frequency shifted towards lower frequency region with the increasing amount of Co substitution. And the minimum reflec- tion loss of the PrNi5 xCox powders increased first and then decreased with the increasing amount of Co substitution. The PrNisCox alloys possessed the excellent microwave absorbing properties. The minimum reflection loss of the PrNi4.gCo0,1 alloy all could reach 20.0 all3 with the coating thickness ranging from 1.8 to 3 ram. The minimum reflection loss of PrNi4.gCoo.l powders was -36.20 d13 at 7.76 GHz, and the frequency bandwidth ofR〈10 dB reached about 1.50 GHz with the best matching condition d=2.0 ram.

关键词： PrNi5 alloy Co substitution structure electromagnetic parameters microwave absorbing properties rare earths

Preparation and microwave absorption properties of NdFeB alloys

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Journal of Rare Earths 2015年第5期33卷 514-518页

作者：熊吉磊潘顺康成丽春刘星林培豪姚青荣 School of Material Science and Engineering Guilin University of Electronic Technology School of Materials Science and Engi-neering Central South University College of Chemistry and Life Sciences Hezhou University

In order to improve the microwave absorbing properties of NdFeB alloys, as-jet milled powders were further processed in a planetary mill. The phase structure, morphology and particle size of the alloy powders were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and laser diffraction-based particle size analyzer, respectively. The saturation magnetization and electromagnetic parameters of the powders were determined by a vibrating sample magnetometer （VSM） and a vector network ana-lyzer （VNA）, respectively. The results showed that the saturation magnetization decreased as the milling time increased. The mini-mum absorption peak frequency shifted towards the lower region and the reflection loss values increased with increasing the ball mill-ing time. The minimum absorption peak value of the powders milled for 15 h on the basis of jet milling reached–44.4 dB at 11.04 GHz, and the bandwidth of R〈–10 dB was 1.2 GHz with the best matching thickness of 1.8 mm.

关键词： jet milling ball milling NdFeB alloys magnetic properties microwave absorbing properties rare earths