磁化水对水泥石强度的影响

主要研究了磁化水对水泥砂浆力学性能的影响.试验中研究的磁化参数包括磁化器的有效长度、水流通过磁水器的速度、水流循环次数和养护时间.结果显示:采用磁化水拌制的水泥砂浆的强度和基准空白试样相比有很大提高;当水流速度达到0.11m.s-1时,磁场强度800mT时强度提高最明显.同时对掺有粉煤灰的砂浆试件在合适的磁化条件下,其早期强度也可以有所提高.因此,用磁化水拌合混凝土具有较好的应用前景.     

磁化水处理技术在小化肥厂的应用

总结５年来在水处理技术上采用化学法和磁化法的经过，以详实的工况条件和水质背景条件，介绍磁化水在生产实际中的应用情况，并就化学法和磁法化作工厂成本分析比较。     

磁化处理煤油的空气/油/水界面张力影响初探

用吊环测张力法研究了煤油在0～80 mT、0～60 min、30～60℃磁化条件下,其空气/油/水界面张力的变化规律。结果表明:在60 mT、30 min和30℃条件下,油/水界面张力值降低了19.2%,煤油接近磁饱和,继续单一增加磁场强度和延长磁化时间对油/水界面张力影响小。空气/油界面张力值受磁化时间和磁化强度的影响小,但随磁化温度30～60℃的升高,磁化煤油空气/油界面张力值降低得较未磁化煤油的慢,磁化煤油的油/水界面张力值先升高后降低逐渐与未磁化煤油的值接近。     

基于水处理的磁分离技术研究进展

磁分离技术具有独特的分离原理,在水处理领域中具有较好的经济性和实用价值。随着超导磁材、等离子体技术、催化改性技术、生物技术等的发展,磁分离技术已在水处理领域获得广泛应用。对磁种、磁分离工艺的研究现状进行综述,并简述其在水处理行业的应用情况,探讨了磁分离技术未来的应用前景。     

磁分离技术在水污染治理中的应用

磁分离技术作为一种高效、环保的分离技术,本身具备了分离速率快、效率高、无二次污染等优点,在水处理领域备受关注和应用。随着超导高梯度磁分离技术以及磁分离器设计的进一步发展,磁分离技术在水处理领域逐渐显示出巨大的应用潜力。本文简述磁分离技术和磁种的种类,综述磁分离技术在水处理领域的应用,指出了磁分离技术在水处理领域亟待解决的问题。     

水系统的磁化处理技术及其应用

介绍了磁场用于工业水处理的历史.从水的微观结构上对水的磁化原理、有效磁化水的条件以及磁化处理后水质的变化做了介绍,分析了磁化水处理的有效性.另外还详细介绍了磁化水处理的装置,同时对磁化水的防垢除垢、防腐蚀原理以及杀菌机理进行了说明.最后探讨了我国因腐蚀产物、结垢造成的能源浪费和化学清洗造成的污染和经济损失,说明了磁化水处理技术的广阔应用前景.     

磁絮凝技术在水处理中的应用研究进展

系统综述了磁絮凝技术在水处理中的应用研究进展,具体介绍了磁絮凝技术的特点、影响因素、强化去除机理以及磁絮凝材料的制备和回收利用,最后从磁材料、磁分离技术、多工艺耦合等方面对磁絮凝的发展方向进行了展望,以期磁絮凝技术在水和废水的低成本、资源化处理中得到更加广阔的应用。     

磁絮凝技术在水处理中的应用研究进展

系统综述了磁絮凝技术在水处理中的应用研究进展,具体介绍了磁絮凝技术的特点、影响因素、强化去除机理以及磁絮凝材料的制备和回收利用,最后从磁材料、磁分离技术、多工艺耦合等方面对磁絮凝的发展方向进行了展望,以期磁絮凝技术在水和废水的低成本、资源化处理中得到更加广阔的应用。     

高效磁化器在水质处理中的应用

磁化技术是一门新兴的科学技术,将磁化技术应用于水的处理,是近年来的热门研究课题,本文分析了磁处理研究现状,及应用磁化器对饮用水的pH、流量、电位值进行了处理前后的对比,记录了七组数据,应用正交方法进行数据处理,得出最优组合。然后又进行了流量和浊度的实验,同样分别记录了七组数据,然后进行了数据分析,得出了磁化器处理水的一般规律。     

钡铁氧体垂直磁化薄膜的磁光特性研究

本文研究了钡铁氧体垂直磁化膜在垂直磁记录及磁光记录方面应用的基本磁及磁光特性。利用射频磁控溅射方法，采用正份及非正份陶瓷靶制备了钡铁氧体薄膜，在纯氧气氛下经不同退火温度晶化，制成钡铁氧体垂直磁化膜。在优化的溅射参数及最佳的退火工艺下，得到了性能良好的钡铁氧体垂直磁化膜。研究了薄膜的磁光记录应用特性，并讨论了溅射工艺参数及退火工艺对薄膜性能的影响     

Effect of magnetic field on surface properties of Bacillus cereus CrA and its Extracellular Polymeric Substances (EPS)

The effect of magnetic field on surface properties of Bacillus cereus CrA and its EPS was studied by zeta potential and FT-IR spectrum. The weak magnetic fields of 6.0–10.0 mT promoted the predominant strain B. cereus CrA to form EPS. The weak magnetic field of 2.4–10.0 mT could improve the bio-adsorption efficiency of anions by decreasing the negative charge of the intact strain, while the magnetic field of 17.4 mT could increase the negative charge of the strain’s EPS by 20% and be responsible for the bio-adsorption of cations. Magnetic field could affect the band intensity and the slight shifting of peaks and the fluctuation of the bacterial absorption capability depended on the magnetic density. The magnetic field energy could affect the hydroxyl group and carboxyl group by forming hydrogen bonding, which were responsible for the adsorption ability of the strain and its EPS.     

磁化水钢纤维再生混凝土早期强度研究

为研究磁化水和钢纤维对再生混凝土早期强度的影响,以C40强度为基准,研究分析不同磁场强度(0 mT、200 mT、260 mT、320 mT)的磁化水和不同体积掺量的钢纤维(0%、0.6%、1.2%)对再生混凝土立方体早期抗压强度和劈裂抗拉强度的影响,并对其微观结构进行观察分析。试验结果表明:钢纤维能够显著提高再生混凝土早期抗压强度和劈裂抗拉强度;磁化水对于再生混凝土抗压强度和劈裂抗拉强度均有不同程度的提升,其中劈裂抗拉强度增幅较小;在0.6%钢纤维掺量和260 mT磁场强度下再生混凝土早期抗压强度增幅较为明显。     

磁场活化水对水泥拌合物性能的影响

水流以一定的速度经过磁场装置处理后得到的水称为磁化水.本实验设计了不同的磁场强度(280 mT,450 mT,650 mT,800 mT)、水流速度(0.4 m/s,0.6 m/s,0.7 m/s,0.9 m/s,1.0 m/s)和水流循环次数等参数来研究磁活化水对水泥拌合物的性能影响.结果表明:磁化水的pH值都高于普通水,不同循环次数的磁化水在紫外区的吸光度也明显增大;当磁场强度为280 mT,水流速度为0.9～1.0 m/s时,磁化水拌和水泥浆有较好的流变性其流动度也增大;磁化水拌制的砂浆试块28 d后的抗压强度有很大提高.     

不锈钢粉尘磁选-还原实验研究

在分析不锈钢电弧炉冶炼粉尘物化性质的基础上,探索了磁选-还原工艺降低不锈钢粉尘中Ca, Mg, O等杂质含量的可能性. 结果表明,采用磁选-还原-磁选工艺处理不锈钢粉尘,磁性物质产率为37.39%,TFe品位达53.66%,主要杂质CaO和MgO总量为11.61%,添加一定量Fe粉和Cu粉后可作为铁基粉末冶金摩擦材料的原料. 综合考虑磁性物质产率、TFe品位和脱钙效果,合适的磁场强度范围为60~90 mT.     

Application of Magnetically Stabilized Fluidized Beds for Cell Suspension Filtration from Aqueous Solutions

Abstract

A magnetically stabilized fluidized bed (MSFBs) utilizing a transverse magnetic field was used to retain cells from cell suspension. The magnetic field permits bed expansion without mixing of the magnetic particles. The bed porosity increased by 75% when the magnetic field intensity increases to 110 mT. The effect of the magnetic field, suspension flow rate, bed height, initial concentration, and pH on the breakthrough curves was studied. According to the experimental results, increasing the initial concentration, flow rate, and pH leads to early breakthrough and inefficient deposition. Additionally, increasing the field intensity and bed height delays the breakthrough point.     

梯度磁场对被动式质子交换膜燃料电池性能的影响

氧气和水是质子交换膜燃料电池（proton exchange membrane fuel cell，PEMFC）电化学反应中的主要成分，梯度磁场能够对二者的物理、化学性质产生影响。通过性能测试实验台，研究了阳极侧加载480mT梯度磁场后，被动式质子交换膜燃料电池（air-breathing proton exchange membrane fuel cell，AB-PEMFC）的性能变化。在此基础上，测试了不同电池温度和氢气流量下电池的性能变化。实验结果表明，在相同环境变量下，于阳极侧加载480mT梯度磁场能够提升AB-PEMFC的电效率。在不同电池温度下，加载480mT梯度磁场的电池效率更优；在不同的氢气流量下，阳极侧加载480mT梯度磁场，能为低流量时AB-PEMFC的电效率提供更明显的增益效果。因此，当AB-PEMFC在低温、低氢流量环境下工作时，在其阳极侧加载480mT梯度磁场能够更好地提升电池性能。实验结果可为AB-PEMFC的性能提升提供一定的参考价值。     

Effect of a YIG nanoparticle additive on the magnetic properties of MnZn ferrites for MHz frequency applications

In this study, MnZn ferrites with added YIG nanoparticles were developed for MHz frequency applications. The effect of the magnetic YIG additive on the power loss, initial permeability, and cutoff frequency of MnZn ferrites was investigated. A small quantity of added YIG effectively reduces the power loss and concurrently increases the initial permeability. Compared to the results for the MnZn ferrite with no added YIG, the optimal MnZn ferrite with 600 ppm added YIG exhibits a reduction in the power loss at 25°C of 56.4% and 36.6% at 1 MHz/50 mT and 3 MHz/10 mT, respectively, and a 13.9% increase in the initial permeability. This sample also exhibits a good stability of the power loss against temperature. The power loss remains below 205 kW/m³ over temperatures ranging from 25 to 140°C. The effect mechanism of YIG addition on the magnetic properties of MnZn ferrites was studied. An analysis based on the equivalent circuit model showed that the reduction in the eddy current loss and power loss mainly results from the increase in the grain boundary resistance caused by the addition of highly resistive YIG.     

Enhanced field emission properties of films consisting of Fe-core carbon nanotubes prepared under magnetic field

Films consisting of carbon nanotubes containing iron (CNTs-Fe) were prepared on tungsten substrates for electron field emission. The films were prepared by drying the mixture of the CNTs-Fe with poly [3-octyl-thiophene] (P3OT) or toluene under a magnetic field using a permanent magnet of surface magnetic flux 340 mT. The field emission properties of the films were measured in comparison with the films prepared without the magnetic field. The films prepared under the magnetic field showed better field emission characteristics than those without the magnetic field, and the electric field to generate the required field emission current was significantly decreased by applying the magnetic field in the film preparation process. Microscopic analyses indicated that the magnetic field had the effect of forcing the CNTs-Fe to stand perpendicular to the substrate, which causes the enhanced field emission properties.     

Paramagnetic defects and exchange coupled spins in pristine ultrananocrystalline diamonds

Electron paramagnetic resonance (EPR) and magnetic susceptibility measurements were done on nanodiamond samples fabricated by the detonation method and purified by acids. Comprehensive acid treatment leads to the reduction of EPR signals of magnetic impurities and revealing two weak and narrow EPR lines with g₁ = 4.26, H_pp = 2.9 mT and g₂ = 4.00, H_pp = 1.4 mT at T = 4 K, separated by the distance of 10.4 mT. The origin of this new doublet EPR signal observed in the well purified sample is discussed. The magnetic susceptibility behavior and doublet EPR signal (g  4) suggest the weak antiferromagnetically exchange coupling of S = 1/2 paramagnetic defects as well as the presence of isolated dimers with S = 1.     

gp‐41 protein production by E. coli in unconventional bioreactor coupled with magnetic field generator

BACKGROUND: In this work recombinant gp‐41 protein production by E. coli in an unconventional bioreactor coupled with a magnetic field generator was studied. The submerged fermentation process was carried out by fed‐batch operation, recycling the culture medium externally through a stainless steel spiral U‐shape tube inserted on the inside of a magnetic field generator. The exposure time and magnetic field induction were varied in a range from 1 to 12 h and 10 to 100 mT, respectively, according to a central composite design with centered face. RESULTS: It was found that the inhibitory or stimulatory effect of magnetic field on cell growth and protein production depended on exposure time and magnetic field strength. The production of recombinant gp41 protein was 20% higher than the control. CONCLUSION The procedure here presented could be an easy‐to‐use approach to improve the efficiency of recombinant protein production by E. coli. Copyright © 2007 Society of Chemical Industry