退火温度对Fe_(73.5)Co_(0.3)Cu_1Nb_3Si_(14.2)B_8合金带材磁性能的影响

用单辊法制备的宽为20 mm,厚为25μm的Fe_(73.5)Co_(0.3)Cu_1Nb_3Si_(14.2)B_8合金带材,绕制成外径为40 mm,内径为25 mm的环型磁芯,再将磁芯进行退火处理。分析了合金带材的晶化行为,研究了退火温度对合金磁芯磁性能的影响。结果表明,淬火态Fe_(73.5)Co_(0.3)Cu_1Nb_3Si_(14.2)B_8合金带材为非晶态,一级起始晶化温度T_(x1)为512.8℃,二级起始晶化温度T_(x2)为671.9℃,当退火温度升高到550℃,在非晶基体中析出Fe(Si)软磁相,形成了非晶和纳米晶双相共存结构。当退火温度低于550℃时,随着退火温度的升高,合金磁芯的初始磁导率μ_i和饱和磁感应强度Bs增大,矫顽力Hc减小;当测试频率f和最大磁感应强度Bm不变时,合金磁芯的有效幅值磁导率μ_a增大,比总损耗Ps和交流矫顽力Hc减小;当测试频率f不变时,合金磁芯的电感Ls和品质因数Q增大。     

高炉粉尘Fe和Zn非熔态分离工艺

开发一种高炉粉尘再资源化处理工艺,采用非熔态还原--磁选分离--Zn的回收、富集方法对典型高炉粉尘进行Fe、Zn非熔态分离研究.结果表明:在910～1 010℃,使用纯H2、CO为还原剂进行非熔态还原,同时实现粉尘中Fe2O3(s)→Fe(s)和ZnO(s)→Zn(g)的高度转变,金属化率达到90%以上,气化脱锌率达到99%以上,且还原过程未发生烧结.还原产物直接经磁选分离、富集得到TFe品位90%的富Fe物料;含锌挥发物经回收、富集得到ZnO含量92%的富Zn物料.成功地将高炉粉尘全部转化为MFe、ZnO等有价资源,实现了零排放,且分离过程不需高温熔融,过程能耗低,无环境污染.     

In vitro biological effects of magnetic nanoparticles

Magnetic nanoparticles (MNPs) have great potential for a wide use in various biomedical applications due to their unusual properties. It is critical for many applications that the biological effects of nanoparticles are studied in depth. To date, many disparate results can be found in the literature regarding nanoparticle-biological factors interactions. This review highlights recent developments in this field with particular focuses on in vitro MNPs-cell interactions. The effect of MNPs properties on cellular uptake and cytotoxicity evaluation of MNPs were discussed. Some employed methods are also included. Moreover, nanoparticle-cell interactions are mediated by the presence of proteins absorbed from biological fluids on the nanoparticle. Many questions remain on the effect of nanoparticle surface (in addition to nanoparticle size) on protein adsorption. We review papers related to this point too.     

Synthesis and characterization of bifunctional terbium complex-based nanoparticles

Novel bifunctional terbium complex-based nanoparticles were developed using a modified Stber method and a layer-by-layer assembly process. A magnetic core of Fe3O4 nanoparticles was coated with a silica shell to form the first layer. Then a ternary Tb3+ complex (TESPPA-Tb), which acted as a luminescent marker, was covalently bound to the silica surface by stable Si-O-Si bonds. The TESPPA monomer was synthesized by binding pyridine 2,6-dicarboxylic acid to 3-aminopropyltriethoxysilane, which was used as a ligand for coordination with the Tb3+ ions. An outer shell of silica was applied to the nanoparticles to allow for versatility with surface functionalization. The nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, ultravioletvisible spectroscopy, vibration sample magnetometer, and photoluminescence spectroscopy. The bifunctional nanoparticles exhibited favorable superparamagnetic behavior and photoluminescence properties of Tb3+. These nanoparticles have potential applications in biolabeling, bioseparation, immunoassays, and pathogenic diagnosis.     

难加工合金材料复杂曲面磁性磨料光整加工技术

磁性磨料光整加工技术是一种非常重要的光整加工技术,与低频振动和超声振动相结合,可实现高精度、高质量和高效率的光整加工。介绍了磁性磨料光整加工、振动辅助磁性磨料光整加工及超声辅助磁性磨料光整加工技术的原理和特点及相关的国内外研究现状。根据难加工合金材料复杂曲面的特点,提出实现复杂曲面磁性磨料光整加工,需要就以下问题开展进一步研究和探索:通过提高加工间隙的磁通量密度及磁能与其他能量复合来提高光整加工效率;建立复杂曲面磁性磨粒光整加工过程控制函数;探讨在磁极工具的空间几何约束作用下复杂曲面磁性磨料光整加工工艺的规划方法等。     

致密油储层CO2驱核磁共振实验研究

针对致密油储层动用困难问题本研究以CO_2为注入介质,对致密油注气开发效果进行评价,并借助核磁共振技术,从微观角度阐述了致密油储层注CO_2的驱替特征。实验结果表明,CO_2驱可以有效启动赋存在致密孔隙中的原油,非混相压力下(10 MPa),CO_2突破快,小孔隙中原油未动用,驱替后原油饱和度分布不均匀,驱替效率低;而在混相压力之上(24 MPa),CO_2突破明显变慢,驱替后原油饱和度均匀下降,大小孔隙中的原油均被启动,采出程度较高。此外从采出原油组成可以看出,高压下CO_2抽提作用非常明显,原油组分以C7~C29为主,几乎不合C30+组分,这表明CO_2会导致原油中重质组分在孔隙中沉积。     

空间光学敏感器/探测器荷电粒子屏蔽技术综述

空间光学敏感器/探测器是航天器的重要组成部分或重要类型,然而大量存在的空间荷电粒子会造成探测器件本底噪声及性能损伤,对空间探测任务产生不良影响。目前对空间荷电粒子的影响缺乏定量评估手段,广泛采用的质量屏蔽、磁偏转和反符合技术在空间荷电粒子屏蔽方面均存在局限性。在对上述方法进行综述的基础上,提出了基于电磁复合场的空间光学敏感器/探测器荷电粒子屏蔽装置的设计思路。     

聚乙烯醇基自形成磁性液体的零场粘滞特性

用共沉淀-酸蚀法,制得了稳定的自形成聚乙烯醇(PVA)基CoFezO4的磁性液体,测量了基液粘度随聚乙烯醇体积浓度(φs)的变化,磁性液体随磁性微粒体积浓度(φv)不变而φs变化和φs不变而φv变化下零磁场粘滞度．比较在不同条件下的实验结果,研究基液和磁性微粒体积分数φv对磁性液体粘滞特性的影响,并解释了实验所得到的η～φ关系．     

偏压自激微波自差机

根据体效应振荡器的变负载检波特性,提出了一种新体制的微波自差机——偏压自激微波脉冲自差机.其特点是振荡器为脉冲微波振荡,其偏压处于自激振荡状态,整机探测距离较大,且具有良好的抗干扰性能。文章较详细地分析了利用体效应振荡器的静态负微分电导产生偏压自激的过程,并讨论了该体制中的多卜勒信号的检测问题。     

遗传神经网络在GMI传感器设计中的应用

 巨磁阻抗（GMI）微磁传感器具有灵敏度高、响应速度快等突出优点,但其输出信号呈高度非线性特性。利用交流偏置方法产生非对称巨磁阻抗效应（AGMI）,对磁场传感器的线性度有一定改善,但仍存在线性范围小、线性误差较大的缺点。BP神经网络具有良好的自学习、自适应和非线性映射能力,但通常训练速度较慢、易陷入局部极小值;遗传算法有很强的全局寻优能力,但其局部搜索能力不足。为充分发挥二者优点,本研究提出一种基于遗传神经网络的传感器非线性误差校正方法,并针对所设计的GMI传感器,设计了适合本系统的遗传神经网络,可通过Matlab软件实现。结果表明,经过训练的网络输出结果有序,网络的非线性映射性能良好,能精确反映该传感器系统的函数关系。该方法运算快速、精度高,对智能GMI传感器的设计具有一定工程应用价值。