BaFe_(12)O_(19)/SiO_2微晶玻璃陶瓷的柠檬酸盐Sol-Gel合成及其微波性能的研究

采用柠檬酸 Ｓoｌ－ｇｅｌ工艺合成了 ＢａＦｅ12Ｏ１９／ＳｉＯ２微晶玻璃陶瓷,并对其介电常数及其磁导率在１００ＭＨｚ～６ＧＨｚ下的变化规律进行了研究.结果表明,ＢａＦｅ１２Ｏ１９／ＳｉＯ２微晶玻璃陶瓷的合成与体系中 Ｆｅ／Ｂａ、烧结温度密切相关;其介电常数、磁导率基本都随测试频率的增加而下降;介电损耗值最大达到０．４０,磁损耗值较小．     

反应型纳米级磁核聚烯烃类磁性高分子材料的研究：Ⅲ.纳米级CrxFe3—x…

在磁性高分子材料的研究中，为了获得磁性能高、粒径小和稳定性好的纳米晶磁核，作者对ＣｒｘＦｅ３－ｘＯ４纳米晶磁性载体的制备和性能作了研究。通过化学共沉淀法制得的ＣｒｘＦｅ３－ｘＯ４纳米晶，具有２０－３０ｎｍ的粒径，比饱和磁化强度σｓ≥５０ｅｍｕ／ｇ，磁学性能Ｈｃ（矫顽力）近纯Ｆｅ３Ｏ４的３倍。     

反应型纳米级磁核聚烯烃类磁性高分子材料的研究Ⅲ．纳米级Cr_xFe_3－_xO_4磁性载体的制备和性能研究

在磁性高分子材料的研究中，为了获得磁性能高、粒径小和稳定性好的纳米晶磁核，作者对ＣｒｘＦｅ３－ｘＯ４纳米晶磁性载体的制备和性能作了研究。通过化学共沉淀法制得的ＣｒｘＦｅ３－ｘＯ４纳米晶，具有２０－３０ｎｍ的粒径，比饱和磁化强度σｓ≥５０ｅｍｕ／ｇ，磁学性能ＨＣ（矫顽力）近纯Ｆｅ３Ｏ４的３倍     

纳米LaFeO3湿敏特性的研究

用柠檬酸盐法制备纳米晶ＬａＦｅＯ３材料，平均粒径为１５ｎｍ，纳米ＬａＦｅＯ３湿敏元件的灵敏度高于陶瓷ＬａＦｅＯ３湿敏元件。在１０－９８％ＲＨ湿度范围电阻变化三个数量级。     

铁酸钴纳米晶体材料的制备

以ＦｅＳＯ４·７Ｈ２Ｏ和ＣｏＳＯ４·７Ｈ２Ｏ为原料,首先制备出晶粒细小的盐渍化碱式碳酸盐前驱体。在３００—７００℃焙烧１小时后,制备出ＣｏＦ２Ｏ４纳米晶体材料,经ＸＲＤ和ＴＥＭ检测,粒径为１０—４０ｎｍ,粒度均匀     

铁酸钴钠米晶体材料的制备

以ＦｅＳＯ４．７Ｈ２Ｏ和ＣｏＳＯ４．７Ｈ２Ｏ为原料,首先制备出晶粒细小的盐渍 化碱式碳酸盐前驱体。在３００－７００℃焙烧１小时后,制备出ＣｏＦ２Ｏ４纳米晶体材料,经ＸＲＤ和ＴＥＭ检测,粒径为１０－４０ｎｍ,粒度均匀。     

BaMnZnCoTi-W型铁氧体微波吸收剂的制备和特性研究

对用Ｃｏ２＋、Ｔｉ４＋部分置换Ｆｅ３＋的Ｂａ（ＭｎＺｎ）ａＣｏｂＦｅ１６－ｙＣｏ２＋０．５ｙＴｉ４＋０．５ｙＯ２７－Ｗ型平面六角晶系微波铁氧体吸收剂的制备和特性进行了研究,并对其复介电常数的实部ε′和虚部ε″、磁导率的实部μ′和虚部μ″、损耗随微波频率、Ｃｏ２＋、Ｔｉ４＋含量、涂层厚度的变化作了测试和分析,发现当ｙ＝１．０时铁氧体的吸收性能最佳,其最佳厚度为１．４０ｍｍ,吸收衰减最大达２７．５ｄＢ。     

Fe—47wt%Ni纳米晶粉芯磁谱及其压力效应

用蒸发冷凝法，制备成不同平均粒径的Ｆｅ－４７ｗｔ％／Ｎｉ纳米晶粉。将其压成小圆环，测其室温磁谱。结果表明，Ｆｅ４７ｗｔ％Ｎｉ纳主晶粉芯具有较好的高频特性。在（１－３００）ＭＨｚ频率范围内，其复数磁导率实部μ１〉１００，虚部μ２〈２０，损耗解正切ｔｇδ〈０．１，共振频率ｆｒ〉３００ＭＨｚ。当１ＭＨｚ〉ｆ〉４００ＭＨｚ时，μ２及ｔｇδ激剧上升。在（１－３００ＭＨｚ）范围，形成一个很宽的通频带。它有可能     

石英质红外材料的研制

超细石英粉经热压成型（ＨＰ）制成红外陶瓷材料，工艺简单，原料成本低，研究了材料的热膨胀性能，分析了ＳｉＯ２粒度及添加剂Ａｌ２Ｏ３，Ｆｅ２Ｏ３对材料８～２５μｍ的波红外发射率的影响。结果表明，红外材料在３００℃时的热膨胀率小于４×１０＾－６／℃，红外发射率大于８４％。     

碳弧法制备碳包铁纳米颗粒的研究

用直汉碳弧法制备碳包铁纳米颗粒,应用透射电镜（ＴＥＭ）、Ｘ射线衍射分析（ＸＲＤ）和穆斯堡尔谱学进行研究,结果表明,当阳极复合棒中为纯铁粉加石墨粉时,出现３种碳包铁纳米颗粒：α－Ｆｅ,渗碳体（Ｆｅ３Ｃ）和奥氏体;当阳极复合棒中为Ｆｅ２Ｏ３加石墨粉时,出现４种碳包铁纳米颗粒：α－Ｆｅ,渗碳体,奥氏体和ＦｅＯ。它们的尺寸大小在５～５０ｎｍ范围。     

生物型吸波微粒的制备

电磁波吸收微粒对于电磁防护和雷达波的吸收起着关键的作用.采用微生物作为模板,通过溶胶-凝胶处理,在微生物表面包覆了一层Fe3O4,制备了相应的生物吸波微粒,研究了产物的形貌、成份、微波磁参数.实验表明生物吸波微粒表面形成厚度<3μm的尖晶石型铁氧体Fe3O4.包覆铁氧体的螺旋形生物吸波微粒性能良好.采用硅橡胶作为粘结剂制备了1.2mm厚的参杂螺旋形生物吸波微粒的涂层,结果显示该涂层在10～16GHz内反射损失>-10dB.     

Polymer Bonded Ferrite Materials as EMC Components

Polymer bonded ferrites composed of a mixture of Mn‐Zn ferrites or Ni‐Zn ferrites in a polymer binder (PE, PA) were prepared and tested as electromagnetic‐wave absorbing materials. Test samples and cases were prepared by hot or injection molding. Permeability spectra show loss contributions in the frequency range 100‐1000 MHz. Absorption measurements of injection molded polymer‐ferrite cases display a 3‐5 dB better attenuation characteristics compared to graphite‐loaded polyamide housings.     

PAn/Fe3O4网状纳米复合物的合成表征及吸波性能

在十六烷基三甲基溴化胺（CTAB）存在下,采用原位化学氧化聚合法制备了聚苯胺／Fe3O4网状磁性纳米复合材料,通过改变Fe3O4纳米粒子在聚苯胺（PAn）中的含量获得了电磁性能可调的纳米复合物,采用FT—IR、XRD、SEM、TEM、电导和磁性能测试对复合物进行了表征,通过矢量网络分析仪获得了试样在2—18GHz范围的复介电常数和复磁导率,经计算获得微波反射损耗曲线,发现当样品中Fe3O4的含量为15．8wt％时,在9．0GHz处具有最大的反射损耗-17．1dB,损耗起．过-10dB的频宽为1GHz。     

Synthesis of covalently bonded reduced graphene oxide-Fe3O4 nanocomposites for efficient electromagnetic wave absorption

High-performance electromagnetic (EM) wave absorbers,covalently bonded reduced graphene oxide-Fe3O4 nanocomposites (rGO-Fe3O4),are synthesized via hydrothermal reaction,amidation reaction and reduction process.The microstructure,surface element composition and morphology of rGO-Fe3O4 nanocomposites are characterized and corresponding EM wave absorption properties are analyzed in great detail.It demonstrates that Fe3O4 nanoparticles are successfully covalently grafted onto graphene by amide bonds.When the mass ratio of rGO and Fe3O4 is 2∶1 (sample S2),the absorber exhibits the excellent EM wave absorption performance that the maximum reflection loss (RL) reaches up to-48.6 dB at 14.4 GHz,while the effective absorption bandwidth (RL＜-10 dB) is 6.32 GHz (11.68-18.0 GHz) with a matching thickness of 2.1 mm.Furthermore,radar cross section (RCS) simulation calculation is also adopted to evaluate the ability of absorbers to scatter EM waves,which proves again that the absorption performance of absorber S2 is optimal.The outstanding EM wave absorption performance is attributed to the synergistic effect between dielectric and magnetic loss,good attenuation ability and excellent impedance matching.Moreover,covalent bonds considered to be carrier channels can facilitate electron migration,adjust EM parameters and then enhance EM wave absorption performance.This work provides a possible method for preparing efficient EM wave absorbers.     

CdTe@Fe3O4磁性复合纳米粒子的合成与表征

本文通过层层自组装技术（1ayer-by—layer,LBL）成功制备了CdTe@Fe3O4磁性荧光复合纳米粒子,并对其特性和应用进行了讨论．首先,采用化学共沉淀法,以NaOH为沉淀剂,Fe^2＋和Fe^3＋物质的量的比为1：2．在50℃水相中电磁搅拌30min,制备出具有磁性的纳米Fe3O4,然后表面修饰1,6-己二胺．通过透射电镜（transmission electron microscopy,TEM）对其进行观察,粒径在10nm左右．核壳cdTe@Fe3O4复合功能纳米粒子的合成表明：Fe3O4和cdTc物质的量的比为1：3,pH=6．0,温度30℃,反应时间30min为其最佳合成条件．通过TEM、紫外和荧光光谱对合成的纳米粒子分别进行了表征．cdTe@Fe3O4粒径在12～15nm,最大发射波长从530nm红移到570nm,而最大吸收波长则从530nm红移到535mm．结果表明,磁性Fe3O4表面成功覆盖了CdTe壳层．核壳型CdTe@Fe3O4磁性荧光复合纳米粒子的应用能够实现对DNA进行简便快捷的标记、传感和分离．     

Preparation and characterization of TiO2 coated Fe nanofibers for electromagnetic wave absorber

Recently, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) have become serious problems due to the growth of electronic device and next generation telecommunication. It is necessary to develop new electromagnetic wave absorbing material to overcome the limitation of electromagnetic wave shielding materials. The EMI attenuation is normally related to magnetic loss and dielectric loss. Therefore, magnetic material coating dielectric materials are required in this reason. In this study, TiO2 coated Fe nanofibers were prepared to improve their properties for electromagnetic wave absorption. Poly(vinylpyrrolidone) (PVP) and Iron (III) nitrate nonahydrate (Fe(NO3)3 x 9H2O) were used as starting materials for the synthesis of Fe oxide nanofibers. Fe oxide nanofibers were prepared by electrospinning in an electric field and heat treatment. TiO2 layer was coated on the surface of Fe oxide nanofibers using sol-gel process. After the reduction of TiO2 coated Fe oxide nanofibers, Fe nanofibers with a TiO2 coating layer of about 10 nm were successfully obtained. The morphology and structure of fibers were characterized by SEM, TEM, and XRD. In addition, the absorption properties of TiO2 coated Fe nanofibers were measured by network analyzer.     

金属—PAN—S配合物的极谱研究——Ⅱ:Fe~(3+)—PAN—S—TEA—NH_3·H_2O—NH_4Cl体系配合吸附波

在NH_3·H_2O—NH_4Cl—三乙醇胺底液中Fe(Ⅲ)与PAN—S产生一灵敏的配合吸附波,峰电位在—0.50伏(vs.SCE)。峰电位与铁离子浓度在2.8×10~8～3.4×10~(-6)mol/L范围内线性良好,检出下限可达2.8×10~(-8)mol/L。该法用于乳粉、头发、血清等样品的测定,结果满意。     

化学镀Co—B合金对Fe3O4吸波性能的影响

采用化学共沉淀法制备纳米Fe3O4颗粒，通过胶体钯活化敏化一步法处理后，以KBH4为还原剂、C4H4O6Na2-2H2O为络合剂进行Co-B化学镀，对包覆前后的样品进行了XRD、SEM、TEM、电磁参数等表征以及吸波性能分析。结果表明：Fe3O4表面包覆的纤维状Co-B合金以无定形形式存在，Co-B包覆Fe3O4在2．0～18GHz具有良好的吸波效果．     

晶化温度对纳米镍锌铁氧体吸波性能的影响

本文通过水热法制备纳米Ni0.6Zn0.4Fe_2O_4,研究了晶化温度对样品纯度、粒度、形貌及电磁波吸收性能的影响。结果表明:当晶化温度为160℃时,粒子形貌不规则,并未完全形成Ni0.6Zn0.4Fe_2O_4;纯相Ni0.6Zn0.4Fe_2O_4的形成温度为180℃,粒子呈类球形结构,分布均匀,平均粒径约为20~25nm;但温度高于180℃时,尖晶石结构不稳定性增加,有杂相α-Fe2O3生成,粒子明显增大,团聚严重。晶化温度180℃,晶化时间8h制得的纯相纳米Ni0.6Zn0.4Fe_2O_4吸波性能最好,损耗因子在3.5GHz处达到最大值为1.08。利用共振损耗理论对纳米镍锌铁氧体的吸波机理进行分析,通过Helmholtz方程推导出纳米镍锌铁氧体本征振动频率的计算公式。     

Ni_(0.5)Zn_(0.5)Fe_2O_4铁氧体的制备及其电磁损耗性能

以Zn(NO3)2.6H2O、Ni(NO3)2.6H2O和Fe(NO3)3.9H2O及柠檬酸为原料,采用溶胶-凝胶法制备前驱体,在1 200℃下煅烧3 h合成ZnFe2O4和Ni0.5Zn0.5Fe2O4铁氧体粉体。利用差热分析、X射线衍射、扫描电镜、透射电镜和红外光谱等测试手段对产物进行分析和表征。结果表明:ZnFe2O4和Ni0.5Zn0.5Fe2O4属于立方晶系尖晶石结构,结晶完整,晶粒大小在100 nm左右。在0.2~1.8 GHz的频率下对产品进行了电磁损耗性能测试,发现Ni0.5Zn0.5Fe2O4具有较好的电磁损耗特性。