The Role of Radical Bridges in Polynuclear Single-Molecule Magnets

Employing radical bridges between anisotropic metal ions has been a viable route to achieve high-performance single-molecule magnets (SMMs). While the bridges have been mainly considered for their ability to promote exchange interactions, the crystal-field effect arising from them has not been taken into account explicitly. This lack of consideration may distort the understanding and limit the development of the entire family. To shed light on this aspect, herein we report a theoretical investigation of a series of N -radical-bridged diterbium complexes. It is found that while promoting strong exchange coupling between the terbium ions, the N -radical induces a crystal field that interferes destructively with that of the outer ligands, and thus reduces the overall SMM behavior. Based on the theoretical results, we conclude that the SMM behavior in this series could be further maximized if the crystal field of the outer ligands is designed to be collinear with that of the radical bridge. This conclusion can be generalized to all exchange-coupled SMMs.     

Versatile Near-Infrared Super-Resolution Imaging of Amyloid Fibrils with the Fluorogenic Probe CRANAD-2

CRANAD-2 is a fluorogenic curcumin derivative used for near-infrared detection and imaging in vivo of amyloid aggregates, which are involved in neurodegenerative diseases. We explore the performance of CRANAD-2 in two super-resolution imaging techniques, namely stimulated emission depletion (STED) and single-molecule localization microscopy (SMLM), with markedly different fluorophore requirements. By conveniently adapting the concentration of CRANAD-2, which transiently binds to amyloid fibrils, we show that it performs well in both techniques, achieving a resolution in the range of 45–55 nm. Correlation of SMLM with atomic force microscopy (AFM) validates the resolution of fine features in the reconstructed super-resolved image. The good performance and versatility of CRANAD-2 provides a powerful tool for near-infrared nanoscopic imaging of amyloids in vitro and in vivo.     

一种新的永久周期磁铁聚焦的高功率宽带放大器

 提出了一种新的高功率宽带放大器，它由速调管和自由电子脉塞组成，用永久周期磁铁聚焦。研究了这种器件的电子束聚焦、群聚和辐射。在速调管提供一阶调制系数为30%，波导管的半径1.51cm，摇摆器的磁场振幅0.16T，周期7.92cm，电子束的电压490kV，电流50A和半径0.368cm的条件下，预估这种器件的辐射波频率为11.4GHz，输出辐射功率为18MW，输出辐射带宽为44%。     

Measurement of the Distribution of Magnetic Field in Gyrotron of ECRH System on HL-2A Tokamak

In ECRH system of HL-2A tokamak, we chose a new type of gyrotron imported from Russia. We finished the installation and testing last year with the help of Russian experts. We got a lot of useful data and satisfying results after our experiments with the operating of gyrotron.     

Magnetic behavior of the bond random mixed compound FE(BR x I1−x )2(x = 0.9) with Mössbauer spectroscopy

The bond random mixed compound Fe(Br_0.9I_0.1)₂ has been studied by magnetization and Mössbauer measurements. Although the zero-field cooled and field-cooled magnetization variations are not like a typical spin glass one, the Mössbauer spectrum below Néel temperature shows a hyperfine field distribution. It implies that the 10% FeI₂ mixed in FeBr₂ can be induced by the bond random effect which causes the sample to exhibit a spin glass-like behavior.     

The driving torque of a rotating levitated cylindrical permanent magnet above a superconductor

Due to the Meissner effect, a permanent magnet is levitated, when released above a high temperature superconductor. When there is an inhomogeneous temperature field around the magnet, the magnet might start to oscillate with increasing amplitude until it remains in a continuous rotation. A mathematical model for the described effect is presented which couples heat transfer and electromagnetic forces with the equation of motion, yielding to a multiphysics task. In a detailed analysis it is found, that the torque which drives the rotation of the magnet, is explicitly given in terms of Bessel functions and the Fourier coefficients of order zero and one of the temperature field of the surrounding air.     

Magnetically rotational reactor for absorbing benzene emissions by ionic liquids

A magnetically rotational reactor （MRR） has been developed and used in absorbing benzene emissions. The MRR has a permanent magnet core and uses magnetic ionic liquid [bmim]FeCl4 as absorbent. Benzene emissions were carried by N2 into the MRR and were absorbed by the magnetic ionic liquid. The rotation of the permanent magnet core provided impetus for the agitation of the magnetic ionic liquid, enhancing mass transfer and making benzene better dispersed in the absorbent. 0.68 g benzene emissions could be absorbed by a gram of [bmim]FeCl4, 0.27 and 0.40 g/g higher than that by [bmim]PF6 and [bmim]BF4, respectively. The absorption rate increased with increasing rotation rate of the permanent magnet.     

THE FIRST EXPERIMENT OF A THz GYROTRON WITH A PULSE MAGNET

A THz gyrotron with a pulse magnet has been designed, constructed and operated in FIR FU. It is developed as one of high frequency gyrotrons included in Gyrotron FU Series. The gyrotron has already achieved the first experimental result for high frequency operations whose radiation frequency exceeds 1 THz. In this paper, the design detail and the operation test results for sub-terahertz to terahertz range are described. The second harmonic operation is confirmed experimentally at the expected frequency of 1.005 THz due to TE_6,11 cavity mode at the magnetic field intensity of 19.0 T.     

单分子光子源光子统计的非平衡探测

研究了在Hanbury Brown Twiss探测方式下，非平衡探测系统对光子统计测量的影响。通过记录2个单光子计数器响应的单分子光子源输出的每一个事件，分析具有泊松统计背景的实际单分子光子源的光子统计特性，讨论并给出了非平衡探测系统的单分子光子源Mandel参数。研究表明：非理想的50／50分束器、非理想的线性传输效率和非理想的探测器都会使单分子光子源Mandel参数的实际测量结果小于平衡系统的Mandel参数，最后给出了单分子光子源Mandel参数的非理想探测的校正表达式。     

Rigid nitronyl-nitroxide-labelled anchoring molecules: syntheses, structural and magnetic investigations

The syntheses of two rigid organic molecular rods bearing a nitronyl-nitroxide radical and a terminal nitrogen-based functionality like a pyridine or a cyano group are reported. Both new paramagnetic molecules are fully characterized, including crystal structure analysis. Furthermore their magnetic behaviours in the crystalline state are investigated and their spin concentration corroborate their excellent purity. While the pyridine functionalized rod is synthesized by converting the corresponding benzaldehyde to the phenyl-nitronyl-nitroxide radical, the synthesis of the cyano functionalized rod demonstrates the accessibility of highly sophisticated spin-labelled molecules via cross-coupling reaction with a meta-iodo-phenyl-nitronyl-nitroxide moiety.