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11.
We carried out the first observation of the intermediate state (IS) in the region of metamagnetic phase transition (MPT) in ErFeO3: an external magnetic field H∥c (H=0–4 kOe), the temperature range 2.15–1.6 K. The ranges of the IS existence and the domain structure (DS) features were determined. Likely mechanisms of the IS thermodynamic stabilization and conditions for its visualization in ErFeO3-plates with various crystallographic orientations were analyzed. The thermodynamic model of IS was offered: the intermediate state was stabilized by the mechanical stress that accompanies MPT. Excellent agreement with experiment was achieved. 相似文献
12.
13.
A low‐temperature, efficient and effective method was investigated for phytochemical hydroethanolic extraction of Nasturtium officinale (Brassicaceae). The phytocompounds of the selected plant leaves were identified by high‐performance liquid chromatography, gas chromatography with mass spectroscopy, Fourier transform infrared spectroscopy, and ultraviolet‐visible spectroscopy. Acetic acid, d ‐alanine, octodrine, decanoic acid, and cyclohexylethylamine were the major phytocompounds identified in N. officinale leaves with high similarity match and spectral purity. The reducing and stabilizing potential of the extracted phytochemicals was demonstrated by synthesizing the metal oxide nanoparticles (MoO3) by treating ammonium heptamolybdate tetrahydrate (H4MO7N6O24.4H2O) aqueous complex with bioactive compounds of the leaves. The bio‐synthesized MoO3 nanoparticles were characterized by ultraviolet‐visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, energy dispersive X‐ray spectroscopy, field emission‐scanning electron microscopy, and gas chromatography with mass spectroscopy. Gas chromatography‐mass spectroscopy identified acetic acid, d ‐alanine, and octodrine as stabilizing agents in the synthesis of MoO3 nanoparticles. 相似文献
14.
Sara Basile Natale Badalamenti Ornella Riccobono Salvatore Guarino Vincenzo Ilardi Maurizio Bruno Ezio Peri 《Molecules (Basel, Switzerland)》2022,27(3)
The problems of the environment and human health related to the use of synthetic and broad-spectrum insecticides have increasingly motivated scientific research on different alternatives and among these, the use of green systems, such as essential oils, have been explored. Several species of the Apiaceae and Asteraceae families, aromatic herbs rich in secondary bioactive metabolites, are used in the industrial field for pharmaceutical, cosmetic, and food purposes. Different essential oils extracted from some species of these families have shown acute toxicity and attractive and/or repellent effects towards different insects. In our work, we investigated the toxic potential of Calendula incana subsp. maritima and Laserpitium siler subsp. siculum essential oils against four insect species, Sitophilus oryzae, Lasioderma serricorne, Necrobia rufipes, and Rhyzoperta dominica, which are common pests of stored products. The composition of both oils, extracted by hydrodistillation from the aerial parts of the two plants, was evaluated by GC×GC-MS. Calendula incana subsp. maritima essential oil was rich in oxygenated sesquiterpenoids, such as cubebol (35.39%), 4-epi-cubebol (22.99%), and cubenol (12.77%), while the Laserpitium siler subsp. siculum essential oil was composed mainly of monoterpene hydrocarbons, such as β-phellandrene (42.16%), limonene (23.87%), and β-terpinene (11.80%). The toxicity Petri dish bioassays indicated that C. maritima oil killed a mean of 65.50% of S. oryzae and 44.00% of R. dominica adults, indicating a higher biocidal activity in comparison with L. siculum oil, while toward the other species, no significant differences in mortality were recorded. Calendula maritima oil could be, then, considered a promising candidate for further tests as an alternative biocide toward S. oryzae and R. dominica. The possibility that the relatively high content of oxygenated sesquiterpenoids in C. maritima essential oil determines its higher biocidal activity is discussed. 相似文献
15.
16.
M. Al Jaghoub 《The European Physical Journal A - Hadrons and Nuclei》2001,11(2):175-183
A relation linking the normalized s-wave scattering and the corresponding bound state wave functions at bound state poles is derived. This is done in the case
of a non-local, velocity-dependent Kisslinger potential. Using formal scattering theory, we present two analytical proofs
of the validity of the theorem. The first tackles the non-local potential directly, while the other transforms the potential
to an equivalent local but energy-dependent one. The theorem is tested both analytically and numerically by solving the Schr?dinger
equation exactly for the scattering and bound state wave functions when the Kisslinger potential has the form of a square
well. A first order approximation to the deviation from the theorem away from bound state poles is obtained analytically.
Furthermore, a proof of the analyticity of the Jost solutions in the presence of a non-local potential term is also given.
Received: 3 March 2001 / Accepted: 9 June 2001 相似文献
17.
We report spatially resolved linear laser-induced fluorescence (LIF) and planar laser-induced fluorescence (PLIF) measurements
of nitric oxide (NO) in a pre-heated, high-pressure (4.27 atm), lean direct-injection (LDI) spray flame. The feasibility of
using PLIF in lieu of LIF is assessed with respect to measuring NO concentrations in high-pressure LDI spray flames. NO is
excited via the resonant Q2(26.5) transition of the γ(0,0) band while a non-resonant wavelength is employed to subtract background interferences. LIF
detection is performed in a 2-nm region centered on the γ(0,1) band. PLIF detection is performed in a 68-nm window that captures
fluorescence from several vibrational bands. An in situ NO doping scheme for fluorescence calibration is successfully employed
to quantify the LIF signals. However, a similar calibration scheme for the reduction of PLIF images to quantitative field
measurements is plagued by the laser-excited background. Excitation scans and calibration comparisons have been performed
to assess the background contribution for PLIF detection. Quantitative radial NO profiles measured by LIF are presented and
analyzed so as to correct the PLIF measurements to within the accuracy bars of the LIF measurements via a single-point scaling
of the PLIF image.
Received: 23 November 1999 / Revised version: 17 January 2000 / Published online: 27 April 2000 相似文献
18.
This paper simulated the advection and diffusion behaviors of the moving magnetic fluid in the vessel in the high-gradient magnetic field using Navier–Stokes equations. The particles accumulation behavior and the streamlines and the contour of concentration are all affected by the susceptibility, intensity of magnetic field and its gradient, and the flow velocity and also by the difference in size of vessels. The typical accumulation behaves as a solid obstacle in the flow as result of the competing between magnetic and fluid drag forces, and gives rise to a rigidly bound core region followed by a wash away region near the vessel boundary under the condition of 10 mm vessel in width. While the vessel is near 1 mm in width, the magnetic force is exerted almost on the whole vessel area, the vortex is not seen, the wash away area disappears and the concentration changes in the whole vessel. The results of the analysis provide meaningful information on ferrofluid transport and stabilization for various magnetic drug targeting and the magnetic fluid sealing, and other use in industrial and medical fields. 相似文献
19.
A.S. Alexandrov 《Journal of Physics and Chemistry of Solids》2008,69(12):2971-2974
The electron-phonon interaction in cuprates with c-axis polarised optical phonons, which is roughly one order of magnitude stronger than superexchange, bounds holes into mobile bipolarons. Bipolarons pin the chemical potential within the charge-transfer gap of doped Mott insulators, accounting for unusual kinetics and thermodynamics of doped cuprates such as the Nernst and giant proximity effects, pseudo-gaps, and normal-state diamagnetism. We propose that “quasi-particle” peaks, “Fermi-arcs”, and high-energy “waterfalls” in the photoemission spectra of cuprates originate from the photo-ionization matrix elements of disorder-localised band-tails in the charge-transfer gap. 相似文献
20.
In this study, Pd based on 2-Aminopyrimidine and 1H-benzo[d]imidazol-2-amine functionalized Fe3O4 magnetic nanoparticles [(Pd-APM-PSi-Fe3O4) and (Pd-BIA-PSi-Fe3O4)] was designed and used for the synthesis of di aryl ether by Ulmann cross-coupling reactions. Ulmann reaction performed with mixing of the arylhalides and phenol derivatives in DMF solvent. The prepared catalysts were characterized with various analytical techniques such as FT-IR, XRD, TGA, SEM, TEM, EDX, ICP and VSM. Pd-APM-PSi-Fe3O4 and Pd-BIA-PSi-Fe3O4 catalysts demonstrated good to excellent yields catalytic efficiency for Ulmann reactions in comparison with to commercial palladium catalysts. The catalyst is easily recycled and reused without loss of the catalytic activity. The combined merits of reusable catalyst conditions make the condensation with safe operation, no leaching of pd into environment, low pollution, rapid access to products and simple workup. Also, these novel magnetic nanocatalysts are superior to the industry standard Pd in every relevant aspect. They feature a way higher initial activity, a much more convenient separation, better recycling, and less contamination of the products. Last but not least, they can be very easily prepared from commercially available Fe3O4 nanoparticles using standard laboratory equipment. 相似文献