Cobalt-iron cyanide hollow cubes: Three-dimensional self-assembly and magnetic properties

Cobalt-iron cyanide hollow cubes have been synthesized via a poly(vinylpyrrolidone) assisted solvothermal route. A unique formation process: self-assembly followed by Ostwald ripening process, has been put forward to take account for the construction of hollow cubes. The rod-like nanocrystals first assemble as porous cubes via an oriented attachment process. Then, the porous cubes undergo an Ostwald-ripening process, which create interior spaces and result in the formation of hollow cubes. The magnetic property investigation reveals that K_0.22Co_0.58Fe_2.2(CN)₆ hollow cubes exhibit a ferromagnetic behavior.     

PREPARATION OF POLYALKYLCYANOACRYLATE NANOPARTICLES WITH VARIOUS MORPHOLOGIES

The effects of various reaction conditions on the preparation of polyalkylcyanoacrylate(PACA)nanoparticles are studied. The PACA nanoparticles with different crosslinking degrees and morphology arc prepared. Addition of crosslinkers can not only adjust the particle size,but also change the morphology of PACA nanoparticles. Moreover,the loose network structure of the PACA nanoparticles with core/shell-like morphology is investigated by AFM and TEM in detail.     

稳恒磁场处理对聚乙烯/炭系填料复合材料电导特性的影响

在聚乙烯(PE)、低密度聚乙烯(LDPE)/炭黑、LDPE/石墨、LDPE/碳纳米管的热压成型过程中施加稳恒磁场,研究了磁场处理对聚乙烯/炭系填料复合材料电导特性的影响。研究结果表明:磁场处理能导致聚乙烯的结晶度提高,聚乙烯和LDPE/炭黑复合材料的体积电阻率增加;磁场在石墨片层内和碳纳米管中"诱导"形成感应磁矩,使得石墨片层和碳纳米管分别沿垂直于磁场方向和平行于磁场方向在LDPE中取向,从而导致LDPE/石墨复合材料沿平行于磁场方向的电导率减小,而LDPE/碳纳米管复合材料沿平行于磁场方向的电导率增加。     

Photocatalytic and magnetic properties of Zn1−xCrxO nanocomposites prepared by a co-precipitation method

Polyvinyl pyrrolidone (PVP) capped Zn_1−xCr_xO (0.000001≤x≤0.1) nanocomposites were successfully synthesized using a simple chemical co-precipitation technique. The synthesized nanostructures were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray fluorescence (EDXRF), Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy, photoluminescence (PL) and vibrating sample magnetometer (VSM) measurements. The structural characterization by XRD, TEM, FTIR and EDXRF confirmed the formation of wurtzite structure and incorporation of Cr in the ZnO lattice. The photocatalytic activities of as prepared nanocomposites were evaluated by degradation of methylene blue (MB) dye in aqueous solution under UV/sunlight light irradiation. The results demonstrated that Zn_1−xCr_xO (x=0.0001) nanocomposite effectively bleached out MB, showing as impressive photocatalytic enhancement over pure ZnO and ZnS nanoparticles. This enhanced photocatalytic activity at optimum concentration was attributed to increased absorption ability of light and high separation rate of photoinduced charge carriers on the nanocomposite photocatalyst surface. The VSM measurements showed significant ferromagnetism in Cr-doped ZnO nanostructures and the value of saturated magnetism was found to decrease with increase in Cr content.     

Endo/Lysosome‐Escapable Delivery Depot for Improving BBB Transcytosis and Neuron Targeted Therapy of Alzheimer's Disease

The effective treatment of Alzheimer's disease (AD) is hindered due to the hard blood–brain barrier (BBB) penetration and non‐selective distribution of drugs in the brain. Moreover, the complicated pathological mechanism of AD involves various pathway dysfunctions that limit the effectiveness of a single therapeutic drug. Herein, a dendrigraft poly‐l ‐lysines (DGL)‐based siRNA and D peptide (Dp) loaded nanoparticle is designed that could target and penetrate through the BBB, enter the brain parenchyma, and further accumulate at the AD lesion. In this system, T7 peptide, which specifically targets transferrin receptors on the BBB, is linked to DGL via acid‐cleavable long polyethylene glycol (PEG) to achieve high internalization, quick escape from endo/lysosome, and effective transcytosis. Then, the Tet1, which specifically targets diseased neurons, is modified onto DGL by short PEG. After being exposed, Tet1 could drive the nanoparticles to the AD lesion and release the drugs. As a result, the production of β amyloid plaques (Aβ) is inhibited. Neurotoxicity induced by Aβ plaques and tau proten phosphorylation (p‐tau) tangle is also alleviated, and the cognition of AD mice is significantly improved. Overall, this system programmatically targets BBB and neurons, thus, significantly enhances the intracephalic drug accumulation and AD treatment efficacy.     

Techniques and Apparatus for Measuring Rotational Core Losses of Soft Magnetic Materials

In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.     

Multifunctional Magnetic Optical Sensor Particles with Tunable Sizes for Monitoring Metabolic Parameters and as a Basis for Nanotherapeutics

Magnetic optical sensor particles with multifunctional cores and shells are synthesized via a facile nanoprecipitation method and the subsequent modification of the particle shell. The hydrophobic particle core includes optical oxygen indicators, a light harvesting system, photosensitizers, and magnetic nanoparticles. Further functionalities are introduced by modifying the shell with enzymes, antibodies, multiple layers of polyelectrolytes, stimuli‐responsive polymers, and luminescent indicator dyes. The hydrodynamic diameter is tunable by varying different precipitation parameters.     

磁敏二极管的数值模拟

本文首次实现了具有高复合表面的磁敏半导体器件的数值模拟;探讨了适合于数值模拟的磁敏半导体器件的边界条件及基本方程的定标方法。所得结果与实验数据基本相符,可以说明器件的内部机理,对磁敏器件的优化设计有指导意义。     

行波管中周期永磁聚焦系统的研究

主要讲述了电子注在周期永磁聚焦系统中的运动和磁场选择不当时电子注的脉动情况以及电子注流通率与磁场强度的关系.实验发现,磁场强度并不是越大越好,磁场只在一定范围内才能实现电子注的聚束,电子注流通率与磁场强度成抛物线关系,磁场范围的选取应根据实际情况选择合适的范围.