Our recent research achievements in the perpendicular magnetic anisotropy (PMA) properties of the CoFeB sand- wiched by MgO and tantalum layers are summarized. We found that the PMA behaviors of Ta/CoFeB/MgO and MgO/CoFeB/Ta thin films are different. The larger PMA in the latter film is related to the lower magnetization of CoFeB deposited on MgO. Furthermore, we have demonstrated a large anomalous Hall effect in perpendicular CoFeB thin fihn. Our results show large anomalous Hall resistivity, large longitudinal resistivity, and low switching field can be achieved, all at the same time, in the perpendicular CoFeB thin film. Anomalous Hall effect with high and linear sensitivity is also found in an MgO/CoFeBFFa thin film with a thick MgO layer, which opens a door tbr future device applications of perpendicular ferromagnetic thin films. 相似文献
Anisotropic microarchitectures with different physicochemical properties have been developed as advanced materials for challenging industrial and biomedical applications including switchable displays, multiplexed biosensors and bioassays, spatially‐controlled drug delivery systems, and tissue engineering scaffolds. In this study, anisotropic biohybrid microparticles (MPs) spatio‐selectively conjugated with two different antibodies (Abs) are first developed for fluorescence‐based, multiplexed sensing of biological molecules. Poly(acrylamide‐co‐acrylic acid) is chemically modified with maleimide‐ or acetylene groups to introduce different targeting biological moieties into each compartment of anisotropic MPs. Modified polymer solutions containing two different fluorescent dyes are separately used for electrohydrodynamic co‐jetting with side‐by‐side needle geometry. The anisotropic MPs are chemically stabilized by thermal imidization, followed by bioconjugation of two different sets of polyclonal Abs with two individual compartments via maleimide‐thiol coupling reaction and Huisgen 1,3‐dipolar cycloaddition. Finally, two compartments of the anisotropic biohybrid MPs are spatio‐selectively associated with the respective monoclonal Ab‐immobilized substrate in the presence of the antigen by sandwich‐type immunocomplex formation, resulting in their ordered orientation due to the spatio‐specific molecular interaction, as confirmed by confocal laser scanning microscopy. In conclusion, anisotropic biohybrid MPs capable of directional binding have great potential as a new fluorescence‐based multiplexing biosensing system.
Passive and active polarization elements were created by surface and bulk photo-alignment of LCs, reactive LCs, photo-sensitive LCP and photo-curable monomer/LC composites. The use of different photosensitive liquid crystalline materials for the development of highly anisotropic elements with high spatial resolution and stability or, alternatively, fast switch ability will be discussed. Photo-active and voltage tunable polarization and diffraction elements are presented. For active micro-optic application a photo-addressed patterned retarder was created. Electrically switchable diffraction gratings were generated by interference exposure of photo-curable LC composites at room temperature characterized by droplet free morphology. These polarization sensitive diffraction elements are characterized be excellent optical properties and low switching times. 相似文献
Four three‐ring compounds, consisting of two cyclohexyl rings and one mono‐ or difluorinated phenyl ring, were studied using dielectric spectroscopy methods over a broad frequency range (1 kHz–3 GHz). They exhibit a nematic phase in a broad temperature interval, enriched by a smectic B phase in one case. The static and dynamic dielectric properties were analysed. It was established that the bridging CH2CH2 group placed between cyclohexyl and phenyl rings considerably changes the reference frame of the molecule, unlike the situation when it links two cyclohexyl rings. In the nematic and smectic B phases the motion around the short axis is a Debye process, whereas the rotation around the long axis is split into two processes: independent rotation of the whole molecule and its fluorophenyl part. 相似文献
Five homologous series of 4-substituted phenyl 4′-(4″-alkoxy phenylazo) benzoates (Ina–?e) were prepared in which, within each homologous series, the length of the terminal alkoxy group varies between 8, 10, 12, 14 and 16 carbons, while the other terminal substituent, X, is a polar group that alternatively changed from CH3O, CH3, H, Br, and CN groups. Compounds prepared were characterised by infrared, mass, and H1-NMR spectroscopy and their mesophase behaviour investigated by differential scanning calorimetry (DSC) and polarised light microscopy (PLM). The results were discussed in terms of mesomeric and polarisability effects. Only for the lower group of compounds, I8a-e, that showed a nematic phase, the nematic-to-isotropic transition temperatures (TN–I) were successfully correlated to the polarisability anisotropy of bonds to the substituent X. A comparative study was made between the investigated compounds and two previously prepared isomeric groups. In the first group of isomers, 4-(4′alkoxy phenylazo) phenyl 4″-substituted benzoates (IIna–e), the ester groups are inverted. While in the second, 4-(4′-substituted phenylazo) phenyl 4″-alkoxy benzoates (IIIna–e), two modifications were made, inversion of the COO group, and exchange of the two wing substituents 相似文献