关于某变电站10kV电缆铁抱箍发热的分析

在一次红外测温时发现某变电站10kV电缆铁抱箍存在发热现象,每相电缆由一根单芯电缆和一根三芯电缆组成,单芯电缆铁抱箍温度比三芯电缆铁抱箍温度高很多。经分析认为,电缆中流过的交变电流在其周围产生交变磁场,铁抱箍处于交变磁场中,其内部产生涡流损耗及磁滞损耗导致铁片发热。单芯电缆周围的磁感应强度比三芯电缆的强,所以单芯电缆铁抱箍温度更高。将铁抱箍换成磁导率小的材料能很好地解决发热现象。     

合成草酸亚铁的反应时间对组成的影响

采用硫酸亚铁铵和草酸溶液在酸性介质条件下合成含有结晶水的草酸亚铁。通过优化实验条件、定性产物及组成的测定,实验结果表明,加热反应时间为120 min时,合成样品的结晶水的个数与理论值非常接近,即合成样品为FeC2O4·2.01H2O,且产率为97％其中样品中Fe3+的质量分数为0．28％。TG—DTA分析结果表明, 草酸亚铁分解是由脱水和分解两部分组成的,样品属于二水化合物。从200℃开始,草酸亚铁开始分解,到300℃完全分解为氧化亚铁、一氧化碳和二氧化碳,失重率达56．5％。这主要是由于在氧气中氧化亚铁不稳定,会有少量三氧化二铁生成。由此可见,自制的草酸亚铁可以作为合成磷酸亚铁锂的原材料,可满足其电化学性能的要求。     

热疗用磁流体的热磁稳定性研究

采用两步法制备了环糊精(β-Cyclodextrin)改性纳米四氧化三铁(Fe3O4)磁流体.通过在交变磁场下感应加热对其磁热稳定性进行了研究,在交变磁场下加热后悬浮裸磁颗粒或改性颗粒的磁性液体最高升温分别达到63℃和53℃,感应加热实验结果表明所制磁流体可用于肿瘤的热疗研究.     

磁性二氧化硅纳米粒子的制备及性能

为了克服磁性四氧化三铁纳米粒子易团聚、易氧化、耐酸性差等缺点,提高其在催化剂、靶向药物载体、生物分离、核磁共振成像、磁热疗等领域的利用效率,采用共沉淀法合成了四氧化三铁纳米粒子,然后以其为核用Stber法制备出二氧化硅包覆四氧化三铁的复合纳米粒子. 对包覆前及包覆后的磁性纳米粒子分别进行了X射线衍射、透射电子显微镜、振动样品磁强计的表征,并研究了二氧化硅的包覆对四氧化三铁纳米粒子磁性和耐酸性的影响. 实验结果表明:磁性四氧化三铁及磁性二氧化硅纳米粒子的粒径分别为约20 nm和40 nm;磁性四氧化三铁的磁饱和强度为5.7 emu/g,磁性二氧化硅纳米粒子的磁饱和强度也达到5.1 emu/g;此外,在稍微降低磁性的条件下,表面二氧化硅的包覆显著改善了四氧化三铁纳米粒子的分散性和耐酸性.     

Preparation and Evaluation of Dual Targeting Nanoparticles for Oral Cancer

A dual-receptor targeting delivery system based on acid-cleavage hydrazone bond was developed in the study. The characters of CMCS-hyd-CUR-EGFR-mAb were identified. The in vitro release studies revealed that this drug delivery system was acid-sensitive, and the self-assembled nanoparticles which were spherical. The in vitro results indicated that the dual-receptor targeting nanoparticles could be faster internalized into the Cal-27 cells via receptor-mediated endocytosis, which exhibited better antitumor activity than the one-receptor nanoparticles. The experimental results clearly reveal that CMCS-hyd-CUR-EGFR mAb provides a novel way for drug delivery in oral cancer treatment.     

Magnetic biliary stent targeting to treat hepatoma combining with magnetic nanoparticles

To evaluate the effect of targeting to hepatoma treated by magnetic biliary stent combining with magnetic nanoparticle containing 5-fluorouracil （5-FU）, thirty-two nude mice modes with transplanted hepatoma were divided equally into four groups randomly. Experimental group received magnetic biliary stent and magnetic nanoparticles containing 5-FU. The tumor volume and pathomorphology of all groups was measured. The tumor control rate of the experimental group provided magnetic biliary stent wires and magnetic nanoparticles containing 5-FU is remarkably higher than three other control groups, showing significant curative effect. More apoptosis of tumor cells could be detected easily in experimental group. There are more apoptotic bodies and phagotrophic magnetic particle in apoptosis cells of experimental group under electron microscope. Magnetic biliary stent combining with magnetic nanoparticle containing 5-FU could inhibit the growth of hepatoma, and its curative effect is more remarkable than the traditional methods based on external magnetic fields.     

Preparation of magnetic chitosan nanoparticles and immobilization of laccase

The magnetic chitosan nanoparticles were prepared by reversed-phase suspension method using Span-80 as an emulsifier, glutaraldehyde as cross-linking reagent. And the nanoparticles were characterized by TEM, FT-IR and hysteresis loop. The results show that the nanoparticles are spherical and almost superparamagnetic. The laccase was immobilized on nanoparticles by adsorption and subsequently by cross-linking with glutaraldehyde. The immobilization conditions and characterizations of the immobilized laccase were investigated. The optimal immobilization conditions were as follows: 10 mL of phosphate buffer (0.1 M, pH 7.0) containing 50 mg of magnetic chitosan nanoparticles, 1.0 mg · mL⁻1 of laccase and 1% (v/v) glutaraldehyde, immobilization temperature of 4°C and immobilization time of 4 h. The immobilized laccase exhibited an appreciable catalytic capability (480 units · g⁻¹ support) and had good storage stability and operation stability. The K _m of immobilized and free laccase for ABTS were 140.6 and 31.1 μM in phosphate buffer (0.1 M, pH 3.0) at 37 °C, respectively. The immobilized laccase is a good candidate for the research and development of biosensors based on laccase catalysis. Funded by Key Project of National Science Foundation of China (No. 60537050) and the National Science Foundation of China (No. 60377032)     

轴承内环感应加热拆卸器的研制及其有限元仿真

在理论分析的基础上,研制了基于工频感应加热技术的轴承内环感应拆卸器。通过ANSYS有限元软件,构建了感应拆卸器的基本模型。对感应加热过程中拆卸器内的电磁场和工件内的温度场进行了计算机仿真,得出了磁场强度和温度的分布规律及温度对时间历程的变化规律。仿真结果不仅证明了涡流集肤效应的存在,而且通过对拆卸器磁场和温度场的有限元耦合分析,获得了轴承内环拆卸器的设计参数。通过对轴承内环感应加热温度的测试实验,证明了计算机仿真的正确性。     

Synthesis and characterization of Fe3O4 magnetic nanoparticles and their heating effects under radiofrequency capacitive field

Fe₃O₄ magnetic nanoparticles with diameters varying from 10 to 426 nm were synthesized and characterized. Heating effects of Fe₃O₄ magnetic nanoparticles under radiofrequency capacitive field (RCF) with frequency of 27.12 MHz and power of 60–150 W were investigated. When the power of RCF is lower than 90 W, temperatures of Fe₃O₄ magnetic nanoparticles (75–150 mg/mL) can be raised and maximal temperatures are all lower than 50 °C. When the power of RCF is 90–150 W, temperatures of Fe₃O₄ magnetic nanoparticles can be quickly raised and are all obviously higher than those of normal saline and distilled water under the same conditions. Temperature of Fe₃O₄ magnetic nanoparticles can even reach 70.2 °C under 150 W RCF. Heating effects of Fe₃O₄ magnetic nanoparticles are related to RCF power, particle size and particle concentration.     

加热速率对硫精砂反应性的影响

通过中速加热的鼓泡流化床和低速加热的热重分析仪(Thermal Gravity Analysis,TGA)中,硫精砂反应性的对比,确定了加热速率对硫精砂反应性的影响机理.低加热速率情况下,硫精砂颗粒表面会在低温期生成较厚的致密的铁硫酸盐膜,这阻碍了氧气向硫精砂颗粒内部和生成的SO2或者硫蒸汽向主流的扩散,从而在降低反应物浓度和增加逆反应速度两方面降低了硫精砂颗粒的反应性,不利于脱硫率的提高.因此,避免硫精砂在焙烧制酸装置的给料过程中的低速升温是必需的.     

工业废料铁泥制备柠檬酸铁铵的研究

以铁泥为反应原料制备柠檬酸铁铵.通过对铁泥的预处理,将其中的铁转化为硫酸铁,硫酸铁与氨水反应得到氢氧化铁后与柠檬酸生成柠檬酸铁,加氨水后制得柠檬酸铁铵.考查氢氧化铁的制备、反应温度、反应时间和柠檬酸的加入量等条件对产品质量的影响,通过实验确定最佳条件为：反应温度为95℃,反应时间为2 h,柠檬酸加入量为16 g.用比色法测定柠檬酸铁铵中铁含量,结果表明在最佳条件下制备的柠檬酸铁铵符合国家化学纯标准.     

Simulation and control scheme of microstructure in magnetic fluids

By accounting for the external and internal force acting on the suspended magnetic nanoparticles and motion characteristics of the suspended magnetic nanoparticles in the magnetic fluids,the three-dimensional microstructure of magnetic fluids is investigated by means of the molecular dynamics simulation method. The distribu-tion of suspended magnetic nanoparticles and microstructure of the magnetic fluid are simulated in both absence and presence of an external magnetic field. The ef-fects of the nanoparticles volume fraction,the dipole-dipole interaction potential and the particle-field interaction potential on the microstructures of the magnetic fluids are discussed. The main results obtained here are summarized as follows. The suspended magnetic nanoparticles tend to aggregate and make the irregular distribution structure in the absence of an external magnetic field. When the mag-netic fluid is exposed to a magnetic field,the magnetic nanoparticles suspended in the carrier fluid tend to remain chained-alignment in the direction of the external magnetic field. The tendency of chain-alignment morphology of the suspended magnetic nanoparticles is enhanced with the nanoparticles volume fraction,the dipole-dipole interaction potential and the particle-field interaction potential.     

Magnetospirillumsp．AMB-1菌株培养及磁小体形成条件的研究

本文通过改变基础螺菌培养基中琥珀酸添加量、氮源、铁源种类及含量以及培养条件,观察各因素对Magnetospirillumsp．AMB-1生长量及磁小体形成量的影响．单因素实验结果表明：其最适生长温度为30℃,pH为6．9,250mL锥形瓶中装液量为70％,在添加0．80g琥珀酸、并以0．12gNaNO3为氮源、2．0μmol／L奎尼酸铁为铁源的基础螺菌培养基中按2％的接种量,静置培养4d后,趋磁细菌的吸光度可达0．853A,磁小体的形成量Cmag值为1．673．     

选区激光熔化3D打印钛合金及其复合材料研究进展

综述：生物医用铁基磁性纳米颗粒的制备研究进展

毛宇,李艳,顾宁

（东南大学 生物科学与医学工程学院,江苏省生物材料与器件重点实验室,生物电子学国家重点实验室,南京 210096）

摘要：磁性纳米材料具有独特的物理性能、化学性能以及生物效应,是一类重要的功能材料,可以应用于很多领域。在过去的几十年,铁基磁性纳米材料由于其优越的磁性能和巨大的生物医用潜力在生物医学领域引起了大量的关注。特别是具有诊断和治疗功能的磁性氧化铁纳米颗粒一直在生物医学领域发挥着重要作用。磁性氧化铁纳米颗粒是良性的、低毒的、生物相容且生物可降解的,是目前美国食品及药物管理局批准的唯一可用于临床的无机磁性纳米材料。本综述主要介绍了生物医用铁基纳米材料包括铁单质纳米颗粒、铁基合金纳米颗粒及磁性氧化铁纳米颗粒的制备研究进展,重点介绍了磁性氧化铁纳米颗粒的制备方法,并总结指出了磁性氧化铁纳米颗粒制备方法发展的重要性。

关键词: 铁基磁性纳米材料;生物医用;磁性氧化铁纳米颗粒;诊断和治疗功能;制备方法

     

Heating and melting mechanism of stainless steelmaking dust pellet in liquid slag

The heating and melting mechanisms of the pellets immersed in liquid slag were investigated, and the effect of the pellet heating and the melting conditions were studied. The results show that the dust component in the pellet is melted from the surface and no metallic elements are melted before the dust component, the time for the pellet completely melted is reduced as the iron powder content increases since the metallic iron has high thermal conductivity. These are four stages of heating and melting of pellet in liquid slag, they are the growth and melt of solid slag shell, penetration of liquid slag, dissolving of dust component and melting of reduced metals. The lifetime of the solid slag shell is in the range of 7-16 s and increasing the pre-heating temperature of the pellet and the slag temperature can shorten the slag shell lifetime. The time for the dust component in the pellet to be melted completely is in the range of 20-45 s and increasing the pre-heating temperature, especially in the range of 600-800 ℃, can obviously reduce the melting time. A higher slag temperature can also improve the pellet melting and the melting time is reduced by 10-15 s when the slag temperature is increased from 1 450 to 1 550 ℃. The pellet with higher content of iron powder is beneficial to the melting by improving the heat conductivity.     

载铁颗粒活性炭的制备及其表征

本文以废活性炭为原料,氧化铁为添加剂,通过高温煅烧的方法制备载铁颗粒活性炭（IOC-GAC）.结果表明,IOCGAC制备的最佳工艺参数为：煅烧终温为900℃,升温速率为6℃·min-1,m（氧化铁）/m（废活性炭）为4：6,恒温时间为0.5h,所得产品的比表面积达630.5m2·g-1,收率为50.9％.对其进行SEM,IR,XRD表征分析,结果表明活性炭的表面负载了一层致密的铁氧化物,且主要以α-Fe、Fe3O4或γ-Fe2 O3的形态存在,饱和磁化强度高达66.247 emu·g-1.     

Extracting indium and preparing ferric oxide for soft magnetic ferrite materials from zinc calcine reduction lixivium

A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material was developed.Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine as raw solution,copper and indium were firstly recovered by iron powder cementation and neutralization.The recovery ratios of Cu and In are 99% and 95%,respectively.Some harmful impurities that have negative influences on magnetic properties of soft magnetic ferrite material are deeply removed ...     

含荧光基团透明质酸衍生物的合成及其荧光性能

以透明质酸钠和7-羟基-4-甲基香豆素为原料,合成了具有荧光性能的透明质酸衍生物.通过模拟人体的生理环境,研究了浓度、pH和温度变化对透明质酸衍生物荧光性能的影响.结果表明,透明质酸衍生物荧光强度随浓度的增大而增强,随pH变化其荧光强度变化趋势不明显,较为稳定,随温度的变化其荧光强度基本保持稳定.为以后探索具有药物载体透明质酸在机体内的作用机理及其靶向作用提供良好的实验基础.     

Memory effect up to room-temperature in Ni/Ni2P core-shell structured nanoparticles

Memory effect has been studied in the system using magnetic nanoparticles with Ni nanocore encapsulated by non-magnetic and oxidation-resistant Ni2P nanoshell acquired through surface-phosphatizing Ni nanoparticles. The self-assembled array with interparticle spacing of about 6 nm shows memory effect up to 200 K below its average blocking temperature of 260 K. And reducing the interparticle spacing of the self-assembled array via annealing can further enlarge the temperature range of memory effect up to room-temperature. The memory effect can be understood based on the thermal relaxation theory of single-domain magnetic nanoparticles. Furthermore, the read-write magnetic coding is realized based on the temperature changes, using the memory effect up to room-temperature, which may be useful for future memory devices.