NiZnCo铁氧体包覆铁填充碳纳米管的吸波性能

利用溶胶凝胶法制备了Ni0.5 Zn0.45 Co0.05 FezO4/铁填充碳纳米管复合粉末,实现了Ni0.5Zn0.45 Co0.05Fe2O4纳米颗粒对碳管的包覆.并用同轴法测量了纳米复合粉末与石蜡混合物的电磁参数,其中纳米复合粉末的添加量分别为30%和60%,根据电磁参数计算了材料的反射率.结果表明纳米复合粉末的主要吸波频段在2～6GHz,当纳米复合粉末添加量为60%(质量分数),厚度为2mm时,微波吸收峰值出现在大约4GHz处,达到5.8dB.与纯Ni0.5Zn0.45 Co0.05Fe2O4纳米粉末相比有了比较明显的提高.     

导电聚苯胺/ 羰基铁粉复合吸波材料

借助导电聚合物和软磁金属良好的电磁波吸收特性, 制备了导电聚苯胺/ 羰基铁粉复合材料。实验中把导电聚苯胺与羰基铁粉以2∶8 的比例制成复合粉, 然后再将复合粉与聚脲粘和剂以2∶8 的比例混合成吸波涂料。检测结果显示, 当聚苯胺电导率为10 -2 S/ cm、羰基铁粉平均颗粒尺寸为1～2μm, 在2～12 GHz 的频段范围可获得优于- 10 dB 的吸波性能。分析表明, 这类材料有望发展成宽频、强吸收、可人为设计特殊频段的优良吸波材料。     

聚苯胺复合薄膜的电磁屏蔽及吸波性能

电磁屏蔽和吸波是导电高聚物的重要应用领域之一.本文总结了目前聚苯胺复合薄膜的基本制备方法,如原位聚合法、共混法、层层自组装法,介绍了表征聚苯胺复合薄膜电磁屏蔽效能和吸波性能的方法,阐述了其在上述领域中的应用,指出了聚苯胺复合薄膜未来需要研究与解决的问题.     

铁氧体/石墨复合吸波涂层的微波吸收性能

本文将固相法制备的磁损耗型Ba0.9Sm0.1Co2Fe16O27铁氧体与电损耗型石墨相结合,通过测试两者的电磁参数,采用YRcomputor软件模拟计算了双层复合吸波涂层的反射率。结果表明：铁氧体/石墨复合吸波涂层在2～8 GHz频段有较好的吸波性能;其中,下层为含量80 wt%的Ba0.9Sm0.1Co2Fe16O27,厚度1.5 mm,上层为10 wt%的石墨,厚度1.5 mm时,该复合涂层表现出优良的微波吸收特性,反射率损耗RL〈-10 dB时,带宽约为3 GHz（3.5～6.5 GHz）,最大吸收值约为-27 dB。     

固相烧结法制备(LiFe)xZn1-2xFe2O4铁氧体材料的吸波性能研究

采用固相烧结法,按不同配方制备了吸波材料(LiFe)xZn1-2xFe2O4(x=0.1、0.2、0.3、0.4、0.45、0.5),研究了Cr2O3、Al2O3等掺杂对(LiFe)0.45Zn0.1Fe2O4吸波特性的影响。结果表明,(LiFe)0.45Zn0.1Fe2O4吸波性能较好,而在(LiFe)0.45Zn0.1Fe2O4中掺入1%的Al2O3对增加-10dB带宽很有帮助。     

吸波剂用量对雷达吸波涂层吸收性能的影响

采用铁氧体、电阻型和电介质型物质作为吸波剂,制备出了具有阻抗渐变结构的三层复合雷达吸波涂层,探讨了表层、中层和底层吸波剂用量对吸波性能的影响.实验结果表明:增加表层、中层或底层吸波剂含量,均能使吸波性能曲线向低频端方向移动,反之,吸波性能曲线向高频端方向移动;选择适当的吸波剂用量才能拓宽、加深涂层的吸波性能.制备的试样中反射损耗可达-18.78dB和-33.15dB,其小于-10dB的频宽分别为4.08GHz和2.68GHz.     

一种新型纳米羰基铁粉吸波涂层的研制

以纳米材料Fe（CO）5为新型损耗介质,研究了复合分散工艺、超声波分散时间、偶联剂对分散性的影响,测量了纳米吸波涂层的吸波性能。结果表明制备的纳米粉末优于其他一些常用的吸收材料。     

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.     

木基多孔炭/铁氧体复合吸波材料的制备与性能表征

以马尾松木材为原料,使用低温预处理、真空浸注和高温原位生长等手段制备了性能优异的木基多孔炭/铁氧体复合吸波材料(WPC/Fe3 O4),采用XRD、XPS、SEM、VNA等技术对复合材料的物相、成分、形貌和电磁特性等进行表征分析,初步阐述了其吸波机理.结果表明:制备的WPC/Fe3 O4具有优异的吸波性能,其反射损耗峰值达-35.6 dB,有效吸波频带宽超过5.6 GHz,并且在3～4.3 mm厚度范围内均可实现对全部Ku频段电磁波的有效吸收;WPC/Fe3 O4具有规则通直的孔隙结构和丰富的异质界面,高温下Fe3 O4纳米粒子均匀生长于木基多孔炭的孔隙和炭壁中;随着碳化温度的升高,WPC/Fe3 O4的介电常数显著增大而磁导率变化较小;WPC/Fe3 O4的电磁损耗机制主要为导电损耗、磁损耗和界面极化损耗.复合材料表现出对Ku频段电磁波的高效与宽频吸收,有望实现其在电子通讯或目标隐身等微波领域的应用.     

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．     

回流法制备纳米 NiZn铁氧体及成相机理研究

采用回流法合成了纳米级的尖晶石相NiZn铁氧体．通过XRD测试和回流液反应过程中pH值变化分析，确定了最佳的回流反应时间为6h，同时对回流反应的机理进行了初步的研究．透射电镜结果显示NiZn铁氧体的颗粒为10-30nm，高分辨透射电镜分析表明回流法合成的铁氧体为单一尖晶石相．用VSM研究了纳米NiZn铁氧体粉料的软磁特性．     

低热固相反应法制备CoFe_2O_4、ZnFe_2O_4和Co_(0.5)Zn_(0.5)Fe_2O_4纳米粉体研究

采用低温固相反应法合成了CoFe2O4、ZnFe2O4和Co0.5Zn0.5Fe2O4纳米粉体。以NH4HCO3和金属盐为原料,生成了前驱体碱式碳酸盐,通过研究不同焙烧温度,并在最佳焙烧温度下得到了CoFe2O4、ZnFe2O4和Co0.5Zn0.5Fe2O4纳米粉体。经X射线衍射(XRD)、热分析(TG-DSC)、透射电子显微镜(TEM)、振动样品磁强计(VSM)等测试手段的分析,结果表明:低温固相反应法能够合成出单相的CoFe2O4、ZnFe2O4和Co0.5Zn0.5Fe2O4纳米粉体。     

微波多元醇法制备单分散Ni1-xZnxFe2O4/MWCNTs与磁性能

以多壁碳纳米管(MWCNTs)为模板,三乙二醇(TREG)为溶剂,采用微波多元醇法制备MWC-NTs负载组成可控的Ni1-xZnxFe2O4(x=0.4、0.5、0.6)纳米复合材料Ni1-xZnxFe2O4/MWCNTs。其结构和形貌通过XRD、SEM、TEM和EDX进行表征,用VSM测试样品的磁性,并探讨了微波功率、微波时间对镍锌铁氧体负载的影响。结果表明立方系尖晶石结构的单分散Ni1-xZnxFe2O4磁性纳米粒子均匀负载在碳纳米管表面,平均粒径约为6nm;其磁性能与镍锌铁氧体的组成有关,随着Zn含量的增加,饱和磁化强度(Ms)先增大后减小,当x=0.5时Ms达到最大值。矫顽力(Hc)都比较小,在室温下表现为超顺磁性。     

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。     

移相器材料Zn、Ti、Sn替代锂铁氧体

为了研制高性能自动跟踪同步通信卫星相控天线阵中的移相器材料,采用普通陶瓷工艺,并加入微量杂质：Bi₂O₃、NiO、Co₂O₃和MnCO₃,且利用氧气氛烧结制备了目前尚未见报道的铁氧体Li_0．625Zn_0．1Ti_0．25Sn_0．1Fe_1．925O₄．结果表明,该材料具有较高的居里温度和较低的介电损耗.并对锂铁氧体Li_0.5（1-y）Zn_yFe_{2.5（1-0.2y）}O₄的微波特性进行了讨论.     

One-dimensional SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrite nanofibers and enhancement magnetic property

SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrite nanofibers of diameters about 100 nm with mass ratio 1:1 have been prepared by the electrospinning and calcination process. The SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrites are formed after calcined at 700 degrees C for 2 hours. The composite ferrite nanofibers are fabricated from nanosized Ni(0.5)Zn(0.5)Fe2O4 and SrFe12O19 ferrite grains with a uniform phase distribution. The ferrite grain size increases from about 11 to 36 nm for Ni(0.5)Zn(0.5)Fe12O4 and 24 to 56 nm for SrFe12O19 with the calcination temperature increasing from 700 to 1100 degrees C. With the ferrite grain size increasing, the coercivity (Hc) and remanence (Mr) for the SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrite nanofibers initially increase, reaching a maximum value of 118.4 kA/m and 31.5 Am2/kg at the grain size about 40 nm (SrFe12O19) and 24 nm (Ni(0.5)Zn(0.5)Fe2O4) respectively, and then show a reduction tendency with a further increase of the ferrite grain size. The specific saturation magnetization (Msh) of 63.2 Am2/kg for the SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrite nanofibers obtained at 900 degrees C for 2 hours locates between that for the single SrFe12O19 ferrite (48.5 Am2/kg) and the single Ni(0.5)Zn(0.5)Fe2O4 ferrite (69.3 Am2/kg). In particular, the Mr value 31.5 Am2/kg for the SrFe12O19/Ni(0.5)Zn(0.5)Fe2O4 composite ferrite nanofibers is much higher than that for the individual SrFe12O19 (25.9 Am2/kg) and Ni(0.5)Zn(0.5)Fe2O4 ferrite (11.2 Am2/kg). These enhanced magnetic properties for the composite ferrite nanofibers can be attributed to the exchange-coupling interaction in the composite.     

Preparation of a new nanosized As2O3/Mn0.5Zn0.5Fe2O4 thermosensitive magnetoliposome and its antitumor effect on MDA_MB_231 cells

The purpose of our research is to explore the preparation method of a new nanosized As2O3/Mn0.5Zn0.5Fe2O4 thermosensitive magnetoliposome and study its antitumor effect on MDA_MB_231 cells. The liposomes prepared by the method of rotatory film and high-pressure homogenization were detected by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), nano-particles detector, atom fluorescence spectrophotometer and differential scanning calorimetry (DSC). The therapeutic effects of the nanosized thermosensitive magnetoliposomes combined hyperthermia on human MDA_MB_231 cells in vitro were evaluated by MTT assay and flow cytometry assay. The results indicated that the nanosized As2O3/Mn0.5Zn0.5Fe2O4 thermosensitive magnetoliposomes were prepared successfully. The liposomes were spherical, and most of them were single-room. The exat average diameter of them was 103.8 nm. EDS showed each nanosized As2O3/Mn0.5Zn0.5Fe2O4 thermosensitive magnetoliposome contained P, Mn, Zn, Fe, and As elements, and this proved liposomes have successfully entrapped As2O3 and Mn0.5Zn0.5Fe2O4. The encapsulation ratio of As2O3 detected by atom fluorescence spectrophotometer was 82.16%. The result of heating test showed that Mn0.5Zn0.5Fe2O4 can serve as a heating source upon alternating magnetic field (AMF) exposure leading the nanosized thermosensitive liposomes to reach its phase transition temperature (42.52 degrees C) and release As2O3. MTT assay and flow cytometry assay revealed that the therapeutic effect of the nanosized As2O3/Mn0.5Zn0.5Fe2O4 thermosensitive magnetoliposomes combined with hyperthermia upon AMF on MDA_MB_231 cells was much better than other groups.     

SINCO陶瓷粉末吸波性的初步研究

对ＳＩＮＣＯ粉末的吸波性作了初步研究。对以氯硅烷为单体合成的聚硅氮烷，经裂解、球磨制得的黑色粉末进行了红外、相分析、元素分析及吸波性测试，并通过发迹单体配比，发迹粉末中Ｃ元素的含量，探究粉末吸波性的变化。实验结果表明，黑色粉末为硅的氮碳氧复合化合物，预相的ＳＩＮＣＯ陶瓷存在；ＳＩＮＣＯ粉末在３８．０￣３９．５ＧＨｚ高频带表现出较好吸波性，衰减大于１０ｄＢ；ＳＩＮＣＯ粉末与Ｆｅ３Ｏ４按一定比例复配后     

Ni0.5Zn0.5Nd0.02Fe1.98O4-聚苯胺纳米复合材料的制备及电磁性能（英文）

在Ni0.5Zn0.5Nd0.02Fe1.98O4纳米粒子表面原位聚合苯胺制备了Ni0.5Zn0.5Nd0.02Fe1.98O4-聚苯胺(PANI)纳米复合材料.铁氧体含量为0%、15%和30%样品的结构、形貌和电磁性能分别采用X射线衍射仪(XRD)、透射电子显微镜(TEM)和HB8510B网络分析仪进行了研究.结果表明,聚苯胺包覆层对Ni0.5Zn0.5Nd0.02Fe1.98O4的结晶度有一定影响.在X波段(8.2～12.4 GHz),复介电常数的实部随铁氧体含量的增加而减小,虚部随铁氧体含量的增加而增大.复磁导率的实部和虚部都随铁氧体含量的增加而增大.     

Synthesis, Characterization and Electromagnetic Studies on Nanocrystalline Nickel Zinc Ferrite by Polyacrylamide Gel

Nanocrystalline nickel zinc ferrite powders （Ni=Zn1-xFe2O4, A for x=0, B for x=0.2, C for x=0.5, D for x= 0.8 and E for x= 1） were synthesized by polyacrylamide gel method. X-ray diffraction （XRD）, transmission electron microscopy （TEM） and wave-guide were used to characterize the composition. The XRD results show that the dried gel powders are amorphous, and the characteristic peaks of the spinel Ni0.5Zn0.5Fe2O4 appear after the gel is calcined at 400℃ for 1 h. When the calcining temperatures are 600 and 800℃, the average grain sizes are identified by TEM to be 10 and 30 nm, respectively. The NixZn1-xFe2O4 powders have both dielectric loss and magnetic loss in the frequency range of 8.2-11.0GHz. With the increase of Ni^2＋ ions content, the dielectric parameters （ε′） and permeability （u′） of the NixZn1-xFe2O4 powders decrease while the dielectric loss （ε″）, magnetic loss （u″） and the reflection loss increase.