A novel high-frequency resistance coating by utilizing nano titania particle

In this paper, a liquid-phase hydrolization method to synthesize nanometer rutile titania directly without transformation from anatase is proposed. By utilizing this method, the particle size of the rutile titania nanoparticles can be controlled by adjusting the reaction conditions, e.g. the concentration of sodium hydroxide solution, reaction temperature, and calcining temperature of the powder. These titania nanoparticles have been used for the preparation of a novel composite insulation coating for magnet wires. First results showed that the lifetime of the modified nanomagnet wire in the inverter-fed motor could be prolonged to eight times compared with the non-modified wire.     

合肥光源储存环束流软慢加速控制

 合肥光源储存环为非满能量注入,束流以200MeV的能量注入到储存环后慢加速到800MeV。介绍了慢加速的理论依据及储存环主电源控制系统的硬件结构,详细描述了束流软慢加速方法中的慢加速表计算及慢加速过程控制。机器运行结果表明:软慢加速方法控制灵活,慢加速过程运行平稳,束流损失很少,能很好地满足合肥光源机器运行和研究的需要。     

SC-200质子加速器输运部磁体电源的输出纹波形成机理分析及其Simplorer仿真

介绍了质子治疗加速器输运部二极磁铁电流源的技术要求、主电路拓扑。该电源要求输出电流精度为25ppm，纹波小于25ppm。电源输出电流纹波由低频纹波和高频纹波组成。对电源输出电流纹波的形成机理进行了详细的理论分析和数学计算。得出了基于冲量控制原理的脉冲宽度调制(PWM)电流跟踪控制技术可以有效消除输入低频纹波对输出电流的影响。同时也对输出电流高频纹波采用两种方法进行了定量的数学分析，并得出量化的结论和计算公式。借助AnsoftSimplorer电路仿真软件构建模型，验证了纹波规律结论及计算公式的准确性，并且提出了相应的纹波抑制策略。     

Reduced exchange coupling and hysteresis loops in two-phased magnetic nanosystem

The reduced exchange coupling has been incorporated in our micromagnetic calculations for the hysteresis loops of Nd₂Fe₁₄B/α-Fe and Sm₄₀Fe₆₀/Ni₈₀Fe₂₀ multilayers. Analysis shows that nucleation and pinning fields are sensitive to the value of the interface coupling constant Jⁱ when the soft layer thickness L^s is small. Hysteresis loops have been obtained for a trilayer system with a soft α-Fe sandwiched between two Nd₂Fe₁₄B layers for different values of L^s and Jⁱ. As Jⁱ decreases, nucleation field decreases while the pinning field increases. In the meantime, the squareness of the loops is deteriorated, which results in smaller energy product. For thick soft layer the coercivity mechanism transforms from pinning to nucleation as the interface coupling decreases, and vice versa. The above calculations have been extended to a Sm₄₀Fe₆₀/Ni₈₀Fe₂₀ bilayer and compared with available experimental data. The theoretical loop is consistent with the experimental one when the value of Jⁱ is taken as 10% of the bulk one, demonstrating that the interface coupling in the experiment is far away from perfect coupling.     

Enhancement of the efficiency of magnetic targeting for drug delivery: Development and evaluation of magnet system

Deep magnetic capture and clinical application are the current trends for magnetic targeted drug delivery system. More promising and possible strategies are needed to overcome the current limitations and further improve the magnetic targeting technique. Recent advances in the development of targeting magnet system show promise in progressing this technology from the laboratory to the clinic. Starting from well-known basic concepts, current limitations of magnetic targeted drug delivery system are analyzed. Meanwhile, the design concepts and evaluations of some effective improvements in magnet system are discussed and reviewed with reference to (i) reasonable design of magnet system; (ii) control modes of magnet system used to generate dynamical magnetic fields; and (iii) magnetic field driving types.     

Spontaneously Blinking Rhodamine Dyes for Single-Molecule Localization Microscopy

Single-molecule localization microscopy (SMLM) has found extensive applications in various fields of biology and chemistry. As a vital component of SMLM, fluorophores play an essential role in obtaining super-resolution fluorescence images. Recent research on spontaneously blinking fluorophores has greatly simplified the experimental setups and extended the imaging duration of SMLM. To support this crucial development, this review provides a comprehensive overview of the development of spontaneously blinking rhodamines from 2014 to 2023, as well as the key mechanistic aspects of intramolecular spirocyclization reactions. We hope that by offering insightful design guidelines, this review will contribute to accelerating the advancement of super-resolution imaging technologies.     

Quantitative Single-Molecule Electrochemiluminescence Bioassay

A single-molecule electrochemiluminescence bioassay is developed here which allows imaging and direct quantification of single biomolecules. Imaging single biomolecules is realized by localizing the electrochemiluminescence events of the labeled molecules. Such an imaging system allows mapping the spatial distribution of biomolecules with electrochemiluminescence and contains quantitative single-molecule insights. We further quantify biomolecules by spatiotemporally merging the repeated reactions at one molecule site and then counting the clustered molecules. The proposed single-molecule electrochemiluminescence bioassay is used to detect carcinoembryonic antigen, showing a limit of detection of 67 attomole concentration which is 10 000 times better than conventional electrochemiluminescence bioassays. This spatial resolution and sensitivity enable single-molecule electrochemiluminescence bioassay a new toolbox for both specific bioimaging and ultrasensitive quantitative analysis.     

永磁微型磁共振成像仪的梯度线圈与图像质量

通过理论分析结合计算机仿真试验剖析了磁共振成像(MRI)中梯度场线性对图像质量影响的原理,在梯度场线性有缺陷的情况下,用实例和计算机模拟直观的展示了重建图像和模拟结果. 结合研发实践发现,在永磁微小口径、低场强用于鼠类等小动物成像情况下,对梯度场线性度的要求远高于文献中提出的指标. 依靠软件改进,图像没有本质的提高,尝试补偿技术耗时费力效果也不理想. 说明了对永磁微小口径成像仪研发线性度更好的梯度线圈是提高图像质量的关键技术之一. 揭示了在理想条件下普适的理论原理,在不同的实践条件下有不同的趋近理想条件要求. 将具有独立知识产权的高线性梯度线圈安装在自行研制的仪器上得到了较好的图像.     

制冷机冷却型超导磁体杜瓦的研制

介绍了带制冷机冷却的超导磁体系统杜瓦的设计、制作及实验结果分析。杜瓦采用 4 0 K、10 K双制冷屏结构 ,其室温磁场孔径为 75 mm,长 4 15 m m。试验结果为 :液氦蒸发率为 0 .6 9升 /天 (在 2 0天连续试验期内 ) ,优于合同规定的指标 (2 .4升 /天 )。双制冷屏由一台双级 G- M制冷机冷却 ,工作时一级冷屏温度为 35 K,二级冷屏温度为 7.0 K。磁体系统的磁场强度为 3T,满足了用户的使用要求     

A unilateral magnet with an extended constant magnetic field gradient

Unilateral magnetic resonance (UMR) has become, in different research areas, a powerful tool to interrogate samples of arbitrary size. Numerous designs have been suggested in the literature to produce the desired magnetic field distributions, including designs which feature constant magnetic field gradients suitable for diffusion and profiling experiments. This work presents a new approach which features extended constant magnetic field gradients with a three magnet array. Constant gradients of more than 3cm extent can be achieved in a very simple, compact and safe design. Diffusion measurements from different positions over the magnet are presented in addition to practical applications for reservoir core plug characterization. The idea of a solenoid as a probe for specific measurements in UMR is introduced. Simple profiling experiments are also presented.