Electromagnetic ion cyclotron (EMIC) waves can cause relativistic electron scattering and atmospheric precipitation, primarily via cyclotron resonant interactions in the Earth's radiation belts. However, the conventional quasilinear resonance theory suggests that the cyclotron resonance condition is not satisfied for 90° pitch angle (PA) electrons, which constitute the majority of electrons in the outer radiation belt, such that scattering mainly affects low‐PA electrons. In contrast to this theory, using test particle calculations, we demonstrate that even exactly 90° PA electrons can be significantly scattered by large‐amplitude EMIC waves. The finite wave force results in the parallel transport of 90° PA electrons away from the equator, corresponding to intrinsically nonresonant scattering. This can lead to parallel velocity that meets cyclotron resonance conditions as local PA deviates from 90°. Different types of resonance are identified depending on the wave normal angle, that is, first‐ and second‐order resonances for parallel and oblique waves, respectively.
Multilayer dielectric elastomer actuators have a wide range of potential applications, but their development and commercial implementation have been hindered by existing manufacturing processes. Existing processes are low-throughput, limited in area, and/or can only process a narrow range of elastomers. This study presents a novel fabrication paradigm that overcomes these challenges: instead of sequentially patterning electrodes directly onto successive elastomer layers, electrode stamps are patterned onto a carrier film in an independent batch-spray process and the electrodes are then stamp-transferred onto each elastomer layer. By modularizing the production and assembly of electrodes, a laboratory-scale implementation of the process achieves a throughput of 15 layers h −1 , a maximum electrode size of 300×300 mm, and tuning-free compatibility with a wide range of elastomers. The batch-spraying paradigm also provides the unique capability to evaluate and modify electrodes before they are assembled into a multilayer; a method of mechanically treating the electrodes is employed to increase the breakdown strength of Elastosil P7670 devices from 15.7 to 33.5 V µm −1 . The electrodes are conductive up to a strain of more than 200% and add negligible stiffness to the multilayer structure. The capabilities of this process to produce useful devices are demonstrated with a large-area loudspeaker and an actuator with 60 active layers.
Small-scale magnetic flux ropes (SMFRs) have been identified at a large range of heliospheric distances from the Sun. Their features are somewhat similar to those of larger-scale flux rope structures such as magnetic clouds (MCs), while their occurrence rate is far higher. In this work, we examined the orientations of a large number of SMFRs that were identified at 1 au by fitting to the force-free model. We find that, while most of the SMFRs lie mostly close to the ecliptic plane, as previously known, their azimuthal orientations relative to the Sun–Earth line are found largely at two specific angles (slightly less than 45° and 225°). This latter feature in turn leads to a strong statistical trend in which the axis of SMFRs lies at a large tilt angle relative to (most often nearly orthogonal to) the corresponding background interplanetary magnetic field directions in the ecliptic plane. This feature is different from previous reports on SMFRs—and in stark contrast to the cases of MCs. This is an important observational constraint that should be considered for understanding SMFR generation and propagation.
Brugmansia arborea L. (Solanaceae), common name angel's trumpet, is an evergreen shrub that ranges from 3 to 11 m in height. 1 This plant is commonly used for ornamental purposes as well as for analgesic, antirheumatic, vulnerary, decongestant, and antispasmodic materials. 2 Many alkaloids were isolated as active compounds from the whole parts of B. arborea. 3-5 However, to our knowledge, a phytochemical study of the flowers of B. arborea has not yet been performed. Thus, this study was launched to search for secondary metabolites from the flowers of B. arborea. Ultimately, two new benzonitrile glycosides were isolated and identified. The isolated single compounds were checked for cytotoxicity on human caucasian gastric adenocarcinoma cells (AGS) and human hepatocyte carcinoma cells (HepG2). This report gives an account of separation and identification for benzonitrile glycosides from the flowers of B. arborea and the potential for anti-cancer effects of the separated compounds.The B. arborea samples were treated with aqueous MeOH, and the extracts were fractionated into EtOAc, n-BuOH, H 2 O fractions (fr). The column chromatography (cc) of non-polar fr led to purification of new benzonitrile glucosides.Benzonitrile glucoside 1, an amorphous powder, gave a reddish brown spot in TLC plates after sprinkling with 10% H 2 SO 4 followed by baking. FT−IR data exhibited the absorption (cm −1 ) of hydroxy (3307), nitrile (2252), and aromatic C C (1602). The molecular formula of 1 was determined to be C 20 H 21 NO 7 from the molecular ion peak [M+H 2 O] − m/z 405.1412 in the HR-negative FABMS spectrum (calcd. for C 20 H 23 NO 8 , 405.1424), which also revealed the unsaturation degree to be 11. Based on the gHSQC spectra, the mentioned proton and carbon NMR data indicated that 1 was a diphenyl monoglycoside. Proton and carbon NMR data in conjunction with DEPT experiments delineated the presence of 20 carbon atoms, consisting of the following functional groups: two methylenes (sp 3 ), eight methines (sp 2 ), five methine (sp 3 ), and five quaternary carbons. The proton NMR displayed the signals of Note
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