Search

The influence of modernized three-electrode ion-plasma sputtering of a complex Fe–Si–B– (Cu, Nb)/(Ni, Mo) target on the structure and properties of sputtered films was studied. The formation of amorphous and nanocrystalline phases in Fe73Si15.8B7.2-(Cu, Nb)4 and Fe78.5Si6B14-(Ni, Mo)1.5 films with a coherent scattering region size of 1.6 nm and 12 nm, respectively, was established as a result of a modernized three-electrode ion - plasma sputtering. The thermal stability of metastable states of films as well as electrical and magnetic properties of freshly prepared and heat-treated films has been investigated. The conditions for obtaining films with low values of the temperature coefficient of electrical resistance (−0.9∙10−5 K−1) and coercive force (HC ∼11 A/m) have been determined. [ABSTRACT FROM AUTHOR]

This paper reports on advanced instrumentation for high pressure research developed for the ESRF beamline ID12 which is dedicated to polarization-dependent X-ray absorption spectroscopy at photon energies from 2 to 15 keV. Emphasis is laid on X-ray optics, the design of diamond anvil cell adapted for tender X-ray range and compatible with low temperatures and with high magnetic field as well as a highly efficient X-ray fluorescence detection system. Several examples have been selected to illustrate the performance of the beamline and show what type of advanced spectroscopic techniques can be used to study the local electronic and magnetic properties of materials under pressure. [ABSTRACT FROM AUTHOR]

In the present study, we elucidate the behaviour of a suspension composed of magnetic disk-like particles that flow in a Hagen-Poiseuille flow in a gradient magnetic field and the trapping characteristics of the magnetic particles. To this end, we utilise multiple pairs of magnetic poles located outside the cylindrical system. Brownian dynamics simulations were performed in order to clarify the dependence of these characteristics on a variety of factors. It is seen that an increase in the magnetic field strength improves the trapping characteristics of disk-like particles if the influence of an applied magnetic field is sufficiently more dominant than that of a flow field and that of the magnetic particle-particle interaction. In the case of a strong magnetic particle-particle interaction, thin chain-like clusters are formed from an anchored particle trapped around a magnetic pole. If the two poles are sufficiently close to each other, an arch-type cluster is formed between them. We expect that this arch-type cluster may give rise to good trapping performance even in the presence of a strong flow field if the formation arises at a sufficiently large separation distance between the pair of magnetic poles. Highlights We have performed Brownian dynamics simulations for a magnetic disk-like particle suspension in a Hagen-Poiseuille flow. If the magnetic particle-particle interaction is sufficiently more dominant than the flow field, thin chain-like clusters are formed from an anchored particle. As the pole separation distance decreases, an arch-type configuration tends to be formed along the surface of the wall. This arch-type cluster that is formed between the pair of magnetic poles may be expected to improve the trapping characteristics depending on the pole separation distance. [ABSTRACT FROM AUTHOR]

The fastest growing modes in anisotropic rotating magnetoconvection (RMC) processes are presented. After reminding the state of the art, we present our new approach that applies to isotropic as well as anisotropic diffusivities' conditions. We describe three cases: T (only temperature perturbation is time dependent), Q (temperature and velocity field perturbations are time dependent, but magnetic field perturbation is time independent) and G (temperature, magnetic and velocity field perturbations are time dependent). Isotropies as well as anisotropies are further distinguished by values of molecular and turbulent diffusivities. We show that T case does not describe properly convection in the Earth's outer core conditions, because it implies too huge Ekman numbers for the transition between the RMC modes of weak and strong magnetic field types. In G case, the convection is usually much more facilitated than in the T case: instabilities may arise with much smaller values of Ekman number and, in general, all types of convections occur with values of the physical parameters of the Earth consistent with the most reliable estimations. We demonstrate (and indicate) that Q and G cases can be well suited for the magnetic field of the Earth (and for other planetary magnetic fields), but only G case may correspond to turbulent stay of the Earth's core. We prove that, analogously like in the marginal modes, the value of anisotropic parameter α (the ratio between horizontal and vertical diffusivities) crucially influences the convection. The cases of $ \alpha α < 1 ( $ \alpha >1 $ α > 1) strongly decrease (increase) the Ekman numbers at which the RMC modes of weak and strong magnetic field types change between each other. Finally, we show and stress that not all types of anisotropies in the fastest growing modes can be equally strong. More specifically, we show that a fixed Rayleigh number puts a constraint on the maximum value of α, but do not put any lower positive limit on the minimum value of α. This special constraint is given by the necessary positiveness of the growth rate of the fastest growing modes. Our RMC approach allows to easily deal with very huge wave numbers and Rayleigh numbers as well as with very small Ekman numbers, what is usually not possible in the standard geodynamo simulations. [ABSTRACT FROM AUTHOR]

Hybrid traps for the simultaneous confinement of neutrals and ions have recently emerged as versatile tools for studying interactions between these species at very low temperatures. Such traps rely on the combination of different types of external fields for the confinement of either species raising the question of interactions between the individual traps. Here, the influence of a strongly inhomogeneous magnetic field used for trapping neutrals on the trapping and laser cooling of a single $ \hbox {Ca}^+ $ Ca + ion in a radiofrequency ion trap is studied theoretically using molecular-dynamics simulations based on multilevel rate equations. The inhomogeneous magnetic field couples the different components of the ion motion and introduces position-dependent Zeeman splittings. Nonetheless, laser cooling is still found to work efficiently as the ion samples different magnetic field strengths and directions along its trajectory. Offsetting the centres of the two traps generates a linear magnetic-field gradient so that multiple lasers are required to address the resulting range of Zeeman splittings in order to ensure efficient cooling. The present study yields detailed insights into the ion cooling dynamics in combined magnetic and radiofrequency electric fields relevant for the characterisation and optimisation of hybrid trapping experiments. [ABSTRACT FROM AUTHOR]

In this paper, we report a density functional theory (DFT) calculation study based on the full potential linear augmented plane wave (FP-LAPW) to investigate the effect of Fe incorporation in hexagonal BaTiO3 with a high Fe content x = 0.5 : BaTi0.5Fe0.5O3.We discuss the structural, mechanical, electronic and magnetic properties as well as the spontaneous electrical polarisation P. The partial Fe substitution in BaTiO3 conserves and doubles its initial polarisation value from 0.12 to 0.25 C/m2. In contrast to nonmagnetic BaTiO3, we observe a net magnetic moment of 6.0 μB/formula unit. But, when the strong correlations among d electrons of Fe atoms are taken into account, the total magnetic is increasing and is equal to 10 μB/formula unit, due to a net increasing of magnetic moment of Fe atoms. Therefore, the coexistence of spontaneous electrical polarisation P along with a magnetic moment leads to a new and interesting multiferroic behaviour. We also observe a half-metallic behaviour in which spin down bands structure shows metallic character whereas spin up bands structure shows semi-conductor character with an energy gap of 1.48 eV. This reveals that the multiferroic BaTi0.5Fe0.5O3 could be potential candidate for spintronics devices. [ABSTRACT FROM AUTHOR]

The present research paper handles a 2D deformation in a homogeneous thermoelastic photothermal semiconducting medium subjected to a magnetic field and initial stress with an internal heat source. The problem is framed in the dimensionless form and resolved utilizing the normal mode analysis method. Based on a numerical study using the parameters of silicon as a target, the physical data were attained and tested. They presented the magnetic field and initial stress. It is observed that the magnetic field and initial stress exert some influence in the P-waves in a photothermal semiconducting medium due to internal heat source. The distribution of these quantities was represented graphically with and without the internal heat source, as well as the magnetic field and the initial stress. [ABSTRACT FROM AUTHOR]

Nickel-doped manganese dioxide nanoparticles (Ni = 0.025, 0.05, 0.075, 0.1 and 0.125 M) were prepared via a facile hydrothermal method. Their structural properties, surface morphology, functional groups and magnetic properties were studied by different techniques like X-ray diffraction, Scanning Electron Microscopy and vibrational spectroscopy. The XRD results revealed that the position of diffraction peaks agreed well with the reflection of a tetragonal structure. The crystallite size ranged from 9.2 to 27.61 nm. SEM images exhibited a smooth surface rod-shaped structure. FTIR studies showed slight shifting of the Mn-O band, which ensured the growth of nanorods. The cyclic voltammetry measurements of Ni-doped MnO2 nanoparticles exhibited an excellent capacitance performance than pure MnO2. At room temperature, the MnO2 nanoparticles exhibited paramagnetic behaviour, whereas Ni-doped MnO2 nanoparticles exhibited superparamagnetic behaviour. This work provides a pathway for the development of high-performance supercapacitors as well as the improvement of magnetic properties of the MnO2 nanomaterials. [ABSTRACT FROM AUTHOR]

In this study a 2D cubic chamber model filled with paraffin is analyzed with and without the inclusion of magnetic Fe3O4 nanoparticles at concentrations of 0.5, 1, 1.5 and 2 wt%, and an external magnetic field of intensities 0.005, 0.01, 0.015 and 0.02 T. It is ascertained that adding magnetic nanoparticles leads the horizontal temperature gradient to be reduced owing to increments in thermal conductivity. Additionally, this feature is found to be accelerated by applying an external magnetic field, which shapes highly conductive cluster formations of nanoparticles. However, since the increase in nanoparticle concentration and magnetic intensity increases the composite viscosity, there is an optimum configuration while applying both schemes. As such, the addition of 1 wt% nanoparticles provides the best results, as the melting time is reduced up to 25% compared to pure paraffin. Meanwhile, the melting time of a 1 wt% nanoparticle-containing phase change material (PCM) in the presence of an external magnetic field is improved up to 24% compared to the case with no external magnetic field. Also, the heat transfer coefficient of a 1 wt% nanoparticle-containing PCM both with and without an external magnetic field is also staggeringly enhanced compared to pure paraffin. Good correspondence with experimental data was achieved. [ABSTRACT FROM AUTHOR]

The preparation of antioxidant-coated magnetic nanoparticles (MNPs) has been studied to improve their biocompatibility, i.e. reducing negative side effects. The theoretical study was focused on the interaction of gallic acid (GA) with ionic iron at the surface of nanoparticles that increased reactivity and favors the uniform dispersion in water of magnetic nanoparticles and the interaction with other molecules of biomedical interest. Experimentally, we worked with an optimal method of coating the MNP with GA at 80°C which led to fine granulation highlighted by TEM, preservation of good crystallinity, proven by XRD as well as magnetic properties suitable for biomedical applications based on magnetically targeted guidance. The study of nanotoxicity was focused on the fate of MNPs eliminated in the biosphere, so the influence on photosynthesis in seedlings in early ontogenetic stages was sought. The small variation, with a positive trend, of the efficiency of photosynthesis was correlated with the balancing of the toxic effects, of ROS generation catalyzed by iron ions from the MNP surface by means of the antioxidant character of GA. [ABSTRACT FROM AUTHOR]

Traditionally, electroplating has involved the continuous deposition of a single layer of metal at constant current. However, electrodeposition of alternate layers can offer benefits such as reduced wear, improved corrosion resistance and higher tensile strength. The alternate layers can involve different morphology or thickness of metal, different metals or the alloy composition of layers with and without included particles. In the case of a single bath, electrocrystallisation is continuous but layers can be tailored to have different chemical composition, phase composition, morphology and microstructure. The composition of layers can also be systematically modified in a gradient fashion. The thickness of each metal layer can vary from >20 μm down to ≈1 nm; in the case of nanometre thick layers, up to 500 layers of 1 nm thick individual layers might be involved. Compact multilayer deposition from a single bath is often achieved by applying a potential waveform in the laboratory or pulsed current in industry. While multilayer electrodeposition is going through a phase of rediscovery, growth and diversification, the field can be traced back to a patent involving Cu–Ni multilayers, in 1905. Progress in multi-layered electrodeposition has made use of contemporary trends in electroplating research, including self-assembled layers, nanowire arrays and the use of deep eutectic solvents for electrolytes. The developing uses of multilayer deposits are seen to span industries as diverse as wear and corrosion resistant coatings, tool bits and heavy engineering. Speciality uses include electronic, optical and magnetic materials as well as catalytic electrode surfaces for electrochemical technology. Recommendations are made for topics which deserve further R & D. [ABSTRACT FROM AUTHOR]

The magnetic particles modified with silicon dioxide (SiO2) and amino groups (-NH2), as well as the magnetic particles modified with human serum albumin (HSA) were synthesized using the approaches we developed before and characterized by physico-chemical methods in this study. Plasminogen was chosen as a model protein since plasminogen plays a major role in the fibrinolytic system and plasminogen level correlates with different pathologies and conditions. For the first time it has been carried out qualitative and quantitative assessment of plasminogen nonspecific binding (noncovalent adsorption) by the particles in buffer and plasma solutions. The fibrinolytic activity of plasminogen on the surface of the particles has been measured by the aid of commercially available kits and appeared to be 28–30% of its initial value. Plasminogen desorption from the surface of particles was studied in phosphate buffer with NaCl and ε-aminocaproic acid. Despite nonspecific plasminogen binding is an undesirable process, the data obtained is valuable for further modification of particles for high-specific proteins extraction from biological fluids or transport of plasminogen by the particles. The perspectives of particles modified with SiO2 and –NH2, and particles modified with HSA for isolation of protein analytes and their quantitative assessment thereafter have been discussed. [ABSTRACT FROM AUTHOR]

The use of magnetic nanoparticles (MNPs) in biomedical applications has been wildly opted due to their unique properties. Here, we designed MNPs loaded with erlotinib (ERL/SPION-Val-PEG) and conjugated them with anti-mucin16 (MUC16) aptamer to introduce new image-guided nanoparticles (NPs) for targeted drug delivery as well as non-invasive magnetic resonance imaging (MRI) contrast agents. Also, the combination of our nanosystem (NS) along with L-Asparaginase (L-ASPN) led to synergistic effects in terms of reducing cell viability in ovarian cancer cells, which could suggest a novel combination therapy. The mean size of our NS was about 63.4 ± 3.4 nm evaluated by DLS analysis and its morphology was confirmed using TEM. Moreover, the functional groups, as well as magnetic properties of our NS, were examined by FT-IR and VSM tests, respectively. The loading efficacy of erlotinib on MNPs was about 80% and its release reached 70.85% over 7 days in the pH value of 5.4. The MR images and flow cytometry results revealed that the cellular uptake of ERL/SPION-Val-PEG-MUC16 NPs in cells with MUC16 overexpression was considerably higher than unarmed NPs. In addition, T2-weight MR images of ovarian cancer-bearing mice indicated significant signal intensity changes at the tumour site 4 h after intravenous injection compared to the non-target MNPs. Our data suggest ERL/SPION-Val-PEG NPs as an image-guided co-drug delivery system for ovarian cancer. [ABSTRACT FROM AUTHOR]

In the present study we have implemented a Brownian dynamics simulation of a Hagen-Poiseuille flow in a cylindrical vessel and have investigated the feasibility of multi-pairs of magnetic poles for exhibiting a good particle trapping performance. We have focused on two representative types of configuration consisting of two pairs of magnetic poles. The first is a vertical configuration of two pairs of poles arranged perpendicular to the direction of the flow field. The second is a parallel configuration, where each pair of magnetic poles is arranged along the surface of the vessel wall. In the case of the vertical pole arrangement, although densely-packed aggregates were formed between the poles, their location was unstable in the flow field and they tended to be carried away downstream. In contrast, a densely-packed cluster formed in the parallel arrangement tended locate in a more stable manner along the surface of the wall where the flow field is weaker. We conclude that under appropriate conditions of the magnetic particle-particle interaction strength, the applied magnetic field strength and the pole separation distance, the parallel arrangement of magnetic poles is the configuration of choice for giving rise to a superior trapping performance. [ABSTRACT FROM AUTHOR]

This article is concerned with the investigation of the generalized magneto-thermoelasticity in an orthotropic non-homogeneous continuum solid with a spherical cavity under thermal stresses. The material used is an elastic and has an inhomogeneity in the radial direction considering the effect of thermal stresses, magnetic field as well as thermal relaxation time. The boundary conditions have been applied for stresses and temperature. The solution for displacement, stress components, and temperature has been obtained by using an integral transform technique. Comparisons are presented to verify the accuracy of the present model with the results obtained previous by others. The effects of the inhomogeneity, relaxation time, and magnetic field on the temperature, stresses, and displacement are computed analytically and displayed by graphs. The results obtained indicate to the strong role for the external parameters in the thermal stresses phenomenon and agreement with the practical results. [ABSTRACT FROM AUTHOR]

Propagation of electro-magneto-thermoelastic disturbances produced by a thermal shock in a conducting elastic half-space investigated. The formulation applied to two-dimensional equations of the three-phase-lag model, Green–Naghdi theory without energy dissipation (G–N II) and Green–Naghdi theory with energy dissipation (G–N III). The normal mode analysis is used to obtain the analytical expressions of the considered variables. Comparisons are made with the results predicted by three theories in the absence and presence of a magnetic field as well as the two-temperature parameter. The results indicated that the effect of time, magnetic field, internal heat source, and two-temperature parameter are very pronounced. [ABSTRACT FROM AUTHOR]

The Ni-Cu-Zn ferrites are one of the most exciting spinel oxides so far because of its diverse applications. In the current study, the ratio of nickel and copper was varied keeping the concentration of zinc constant primarily aiming to examine its effect on cation distribution as well as structural and magnetic properties. The samples were synthesized via the conventional solid state sintering method at a temperature of 1050 °C then subjected to neutron diffraction studies. The magnetic properties were measured using a vibrating sample magnetometer (VSM) which complements the magnetic measurements from the neutron diffraction experiments. The ferromagnetic behaviors of these Ni-Cu-Zn ferrites were explained using the Y-K model and the canting of the magnetic moments were also measured. The lattice parameter 'a' was seen to reduce which results from the replacement of large Cu+ ions (0.73 A °) with the smaller ionic radius of Ni + (0.69 A ∘ ). To accommodate a large number of cations in the spinel lattice, the oxygen atoms restructure themselves as a result oxygen position parameter increased. The net magnetic moment per unit formula decreases as the Ni content is increased up to a level, after which the net moment increased. [ABSTRACT FROM AUTHOR]

We have elucidated the feasibility of trapping magnetic rod-like particles that flow in a cylindrical pipe in terms of a non-uniform magnetic field. We have performed Brownian dynamics (BD) simulations in order to clarify the influence that various factors have on the attachment or trapping characteristics of magnetic rod-like particles to the poles. The employment of a local linearisation approximation enables us to apply the BD method that was fully-developed for a simple shear flow to the present Hagen-Poiseuille flow. In the case of a sufficiently small magnetic interaction between the particles, numerous rod-like particles may attach to the magnetic poles if the influence of a non-uniform magnetic field is sufficiently more dominant than that of the flow field, otherwise, the particles flow away along the centreline of the cylindrical pipe. If the magnetic interactions are sufficiently more dominant than both the flow field and the non-uniform magnetic field, the particles aggregate to form densely-packed clusters that flow away along the centreline area of the pipe without being trapped at the poles. In the situation of insufficient magnetic interactions, thin chain-like clusters may be formed from several anchored particles trapped to the poles and incline in the downstream direction. [ABSTRACT FROM AUTHOR]

Today, the utilization of millisecond pulse laser drilling, despite the extensive applications in different fields, is accompanied by several limitations such as low penetration depth, high thickness of recast layer, and heat-affected zone. In order to overcome these limitations, different techniques such as applying magnetic field as well as utilizing ultrasonic vibrations have been proposed. Up to now, limited investigations have been conducted regarding the effect of simultaneous addition of magnetic field and ultrasonic vibration on microstructural characteristics; therefore, in this paper, the simultaneous effects of magnetic field (0.5 Tesla intensity) and ultrasonic vibrations (with the frequency of 28 kHz and amplitude of 15 μm) on the formed phases, recast layer and heat-affected zone thickness have been studied in laser drilling of Ti6Al4 V. According to the results, 23.53% and 6.31% reductions were obtained in diameter and depth of the drilled hole compared to conventional laser drilling, respectively. Moreover, the diameter of heat-affected zone, in the inlet of the drilled hole, was reduced by 30.33% in this hybrid process compared to conventional laser drilling. Besides, it was observed that the presence of ultrasonic vibrations prevents from the formation of acicular α structure in the recast region of Ti6Al4 V. [ABSTRACT FROM AUTHOR]

We establish magnetic improvements upon the classical Hardy inequality for two specific choices of singular magnetic fields. First, we consider the Aharonov-Bohm field in all dimensions and establish a sharp Hardy-type inequality that takes into account both the dimensional as well as the magnetic flux contributions. Second, in the three-dimensional Euclidean space, we derive a non-trivial magnetic Hardy inequality for a magnetic field that vanishes at infinity and diverges along a plane. [ABSTRACT FROM AUTHOR]

Magnetic Abrasive Finishing (MAF) process is an advanced finishing method involving a dry medium comprising iron and non-magnetic abrasive particles. When this mixture is brought in the magnetic field, it forms a very fine, multiple, and flexible abrasive brushes, which can be used for finishing the magnetic as well as non-magnetic materials such as aluminum. For performing finishing operation on aluminum shaft, novel finishing tool having the fixtures for holding the workpiece and other comprising part have been designed, developed and fabricated. These fixtures are attached to a Lathe machine and moved along the length of the rotating workpiece. The non-magnetic material, which is chosen as aluminum, and the finishing operation is performed on it. Minimum surface roughness 96 nm after the actual surface finish of 400 nm with the change in percentage Ra 76% is achieved using the novel finishing tool. [ABSTRACT FROM AUTHOR]

The compound Ca3Co2O6 undergoes a transition into a spin-density wave (SDW) state near 24 K. Below ∼10 K, this unstable SDW state coexists with a nearly- degenerate commensurate antiferromagnetic state as well as short-range magnetic order. Clear signatures of this strong magnetic disorder have been observed in the response of entropy to changing magnetic field and temperature. We performed a calorimetry study of Ca3Co2O6 and Ca3Co1.9Zn0.1O6 in order to compare their entropic responses at low temperature. Our results for Ca3Co2O6 reveal that ΔS(T, H) ≡ S(T, H)−S(T, H = 0) increases as either temperature or magnetic field increase. In contrast, ΔS data for Ca3Co1.9Zn0.1O6 were relatively unresponsive to changes in temperature or field, suggesting that Zn substitution may reduce the low-temperature magnetic disorder observed in Ca3Co2O6. These results are discussed within the context of two cases (Ca3Co2O6 under applied pressure and Ca2.75R0.25Co2O6 (R = Dy, Lu)) in which a single magnetic ground state is stabilised. [ABSTRACT FROM AUTHOR]

The ventriculus terminalis (VT) is a small ependyma-lined cavity within the conus medullaris that is in direct continuity with the central canal of the spinal cord. Cystic dilatation of the ventriculus terminalis on its own is an extremely rare pathological event in adults whose pathogenesis is uncertain. VT has been described in children as a normal developmental phenomenon. These lesions are often diagnosed incidentally during imaging and are in most cases asymptomatic, especially in children. Symptomatic dilatation of VT in adults is a rare condition with 61cases being reported to date. Symptomatic dilatation of VT in children has not been reported till now. We present a 5 year-old-boy with a sphincteric and walking disorder. The patient was assessed by clinical, electrophysiological and urodynamic investigations as well as magnetic resonance imaging (MRI) of the lumbar–sacral segment with and without gadolinium enhancement. Lumbar–sacral MRI demonstrated the presence of a cystic lesion containing cerebrospinal fluid (CSF), which did not enhance after gadolinium, compatible with the diagnosis of the ventriculus terminalis dilation.The patient underwent laminectomy and the cyst wall was fenestrated with a midline myelotomy. In 6-month of follow-up, urinary problems and gait disturbance improved. [ABSTRACT FROM AUTHOR]

Iron oxide nanoparticles have diverse applications in the fields of medicine, environmental area and analytical chemistry due to features such as a large special surface and simple separation with external field as well as magnetic properties. In this experiment, Fe3O4@SiO2 nanoparticles were synthesized by tetraethyl orethosilicate (TEOS), then modified by 3-aminopropyl trimethoxysilane (APTMS) and functionalized with 2,6-pyridine dicarboxylic acid (pydc). Then, the Fe3O4 and Fe3O4@SiO2-NH-pydc nanoparticles were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Differential thermal analysis (DTA), thermogravimetric analyses (TGA) and Derivative thermogravimetric (DTG). To investigate its magnetic properties vibrating sample magnetometer (VSM) was used. [ABSTRACT FROM AUTHOR]

Except for relatively few polarity reversals the magnitude of the magnetic dipole moment of the earth has remained constant since life first began, allowing evolutionary processes to integrate the geomagnetic field (GMF) into several biological functions. One of these, bearing the classical signature of an ion cyclotron resonance (ICR)-like interaction, results in biological change associated with enhanced proton transport. The wide range of cation masses over which this effect is found suggest a fundamental biological dependence on the GMF, one that functions equally well for electric as well as magnetic fields. Such generalization of ICR requires two things: transparency of tissues to the GMF and suitably tuned ELF resonant magnetic or electric fields. To complement the widely reported ICR responses to applied AC magnetic fields, we hypothesize the existence of weak endogenous ICR electric field oscillations within the cell. This equivalence implies that even in the absence of applied AC magnetic fields, biological systems will exhibit intrinsic GMF-dependent ion cyclotron resonance intracellular interactions. Many ICR effects that have been reported appear as antagonist pairs suggesting that the characteristics of the GMF have not only been incorporated into the genome but also appear to function in an endocrine-like manner. [ABSTRACT FROM AUTHOR]

Overhauser dynamic nuclear polarisation (DNP) represents a potentially outstanding tool to increase the sensitivity of solution and solid state NMR experiments, as well as of magnetic resonance imaging. DNP signal enhancements are strongly linked to the spin relaxation properties of the system under investigation, which must contain a paramagnetic molecule used as DNP polariser. In turn, nuclear spin relaxation can be monitored through NMR relaxometry, which reports on the field dependence of the nuclear relaxation rates, opening a route to understand the physical processes at the origin of the Overhauser DNP in solution. The contributions of dipole-dipole and Fermi-contact interactions to paramagnetic relaxation are here described and shown to be responsible to both the relaxometry profiles and the DNP enhancements, so that the experimental access to the former can allow for predictions of the latter. [ABSTRACT FROM AUTHOR]

Novel monobasic tridentate ONS donor ligand (HL) was synthesized from the condensation reaction of chromone-3-carboxaldehyde with S-benzyldithiocarbazate (SBDTC). Reaction of the ligand with the metal ions copper(II), nickel(II), cobalt(II), oxidovanadium(IV), cerium(III), manganese(II), zinc(II), and cadmium(II) afforded dimeric complexes with the general formula [ML(Y)m(H2O)x]2·(Y)m·nH2O·zCH3OH, Y = NO3 or Cl, m = 0–2, x = 0–2, n = 0–2, and z = 0–1 for all complexes except oxidovanadium(IV) complex which has the formula [VOL(H2O)]2(SO4). Structures of the ligand and its metal complexes were established through elemental, spectroscopic data (FT-IR, UV-Vis, and mass), thermal analyses, as well as conductivity and magnetic susceptibility measurements. The geometrical structures of the metal complexes are octahedral and square planar. The ligand and its complexes were subjected to in vitro bioassays against the gram-negative and gram-positive bacteria and the fungus strain with good results for some of these compounds. The antitumor activity of the ligand and its copper(II) and oxidovanadium(IV) complexes were investigated against HepG2 cell line. The molecular parameters of the ligand and its metal complexes have been calculated on the basis of DFT level implemented in the Gaussian 09 program, and computed data were correlated with the experimental results. The HOMO→LUMO electron transition potentially occurs from S-benzyldithiocarbazate to chromone moieties with 4.048 eV. The Mn(II) complex has the highest value of energy barrier, while Cu(II) complex has the lowest value among the complexes. All synthesized complexes have energy gap lower than free ligand and therefore these complexes are more reactive than the free ligand. [ABSTRACT FROM AUTHOR]

The new cyclodiphosph(V)azane derivatives (1,3-dimethyl-2,4-dioxo-2',4'-bis(2,4-bis(dimethylaminopropylimino)cyclodiphosph(V)azane (H2L1) (1,3-dimethyl-2,4-dioxo-2',4'-bis(2,4-bis(dimethylaminoethylimino)cyclodiphosph(V)azane (H2L2) and (1,3-dimethyl-2,4-dioxo-2'-(dimethylaminoethylimino)-4'-(dimethylaminopropyl-imino)cyclodiphosph(V)azane (H2L3) containing four active coordination centers (NNNN) and their Cu(II) complexes have been synthesized and characterized by elemental analyses, spectroscopic methods, molar conductance as well as thermal and magnetic measurements. The UV–Vis and mass spectra of the ligands and their Cu(II) complexes were also recorded. The copper(II) complexes were found to have magnetic moments of 1.58–1.69 B. M. corresponding to one unpaired electron. The possible geometries of the complexes were assigned on the basis of EPR, electronic, and infrared spectral studies. The absence of water molecules in all complexes was supported by thermal studies. All the thermal decomposition processes ended with the formation of CuO. The kinetic and thermodynamic parameters have been calculated. The ligand (H2L3) and its Cu(II) complexes were screened for their anticancer studies against human breast cancer cell lines MCF-7 and minimum inhibitory concentration was calculated. The screening was extended to the antibacterial activity using Kirby–Bauer single disk susceptibility test for all compounds. [ABSTRACT FROM AUTHOR]

We continue our study of a magnetic Schrödinger operator on a two-dimensional compact Riemannian manifold in the case when the minimal value of the module of the magnetic field is strictly positive. We analyze the case when the magnetic field has degenerate magnetic wells. The main result of the paper is an asymptotics of the groundstate energy of the operator in the semiclassical limit. The upper bounds are improved in the case when we have a localization by a miniwell effect of lowest order. These results are applied to prove the existence of an arbitrary large number of spectral gaps in the semiclassical limit in the corresponding periodic setting. [ABSTRACT FROM PUBLISHER]

We investigate analytically and numerically trapping of submicron aerosol particles in a three-dimensional quadrupole acoustic chamber having hyperbolical configuration. The particle trajectories are described by the Langevin equation accounting for particle random Brownian motion. The particle trapping efficiency is investigated for a range of acoustic field parameters and particle properties. It is shown that submicron diffusive particles can be trapped in a small region near the chamber center. The effect of Brownian motion is to broaden the trapping region. The dimensions of the trapping region can be reduced by increasing the acoustic strength parameter. [ABSTRACT FROM AUTHOR]

Atom chips use current flowing in lithographically patterned wires to produce microscopic magnetic traps for atoms. The density distribution of a trapped cold atom cloud reveals disorder in the trapping potential, which results from meandering current flow in the wire. Roughness in the edges of the wire is usually the main cause of this behaviour. Here, we point out that the edges of microfabricated wires normally exhibit self-affine roughness. We investigate the consequences of this for disorder in atom traps. In particular, we consider how closely the trap can approach the wire when there is a maximum allowable strength of the disorder. We comment on the role of roughness in future atom-surface interaction experiments. [ABSTRACT FROM AUTHOR]

We realize a combined trap for bosonic chromium ( 52 Cr) and rubidium ( 87 Rb) atoms. Initial experiments focus on exploring a suitable loading scheme for the combined trap and on studies of new trap loss mechanisms originating from simultaneous trapping of two species. By comparing the trap loss from the 87 Rb magneto-optical trap (MOT) in the absence and presence of magnetically trapped ground state 52 Cr atoms we determine the scattering cross-section of σ inel , RbCr = 5.0 ± 4.0 × 10 -18 m 2 for light-induced inelastic collisions between the two species. Studying the trap loss from the Rb magneto-optical trap induced by the Cr cooling-laser light, the photoionization cross-section of the excited 5P 3/1 state at an ionizing wavelength of 426 nm is measured to be σ p = 1.1 ± 0.3 × 10 -21 m 2 . [ABSTRACT FROM AUTHOR]

The structure of edge magnetic field lines of the l =2 Yamator (the region outside closed magnetic surfaces) is numerically analysed. Yamator is a new stellarator-type magnetic system, where a significant magnetic well can be formed at moderate values of basic magnetic surface characteristics. In comparison with a straight classical stellarator or a torsatron, this system has a double number of separatrix ribs (or so-called "X-points"). The present investigations give a general idea about the behavior of the edge magnetic field lines in the l =2 Yamator and give grounds to discuss a feasible concept of the divertor. [ABSTRACT FROM AUTHOR]

We report on cooling of an atomic caesium gas closely above an evanescent-wave atom mirror. At high densities, optical cooling based on inelastic reflections is found to be limited by a density-dependent excess temperature and trap loss due to ultracold collisions involving repulsive molecular states. Nevertheless, very good starting conditions for subsequent evaporative cooling are obtained. Our first evaporation experiments show a temperature reduction from 10μK down to 300nK along with a gain in phasespace density of almost two orders of magnitude. [ABSTRACT FROM AUTHOR]

The effect of the density gradient of filled traps on the Schottky barrier capacitance in thin films has been ascertained. Different cases have been considered for various values of L, the profile parameter, and n (n=n exp (-x/L), n being the density of filled traps). It is found that for n>N (N being the ionized donor density), the field distribution shows a minimum whereas a voltage maximum is obtained in the capacitance versus voltage curve. The effect of the density gradient of deep traps has been shown to modify the usual expression for the slope and the intercept of the 1/C versus V curve in the absence of such a gradient. Results of some experimental investigations have also been included to support the theoretical predictions. The experimental study of temperature dependence of capacitance yields an activation energy of 006 ev for coalescence of two deep lying traps to form a single new one. [ABSTRACT FROM AUTHOR]

The current decay process for the determination of trapping time, trap depth and the capture cross section for electrons in a semiconductor has been discussed. Because of the large number of unoccupied traps in the specimen of thin films the decay of current is mainly due to the capture of majority carriers by the trapping centers
The method uses a specimen of vapor-deposited thin film which is subjected to an elevated temperature and a step voltage is applied across the specimen. The density of majority carriers in the conduction band is thus increased by the injection process and the equilibrium is disturbed. Due to the large numbers of shallow traps available in such films, capture of these excess carriers starts taking place and the current decays with time. This decay is found to be double exponential in nature. The total decay is thus due to the trapping at at least two discrete levels.
From the study of this decay, evaluation of trap depths and capture cross sections has been made. The trap depths are found to be 0.06 ev and 0.08 ev and their corresponding capture cross sections are 0.4 x 10 cm and 0.04 x 10 cm respectively, which are in fair agreement with the results reported earlier.
In the present analysis, however, the specimen chosen is a vapor-deposited thin film of CdS with A1 as the electrodes. In thin films the density of trapping centers is likely to be large and at room temperature all but the shallowest traps are filled up. When a fixed biasing potential is applied across the specimen the number of majority carriers in the conduction band increases and the equilibrium is disturbed. The excess carriers are then trapped in these trapping centers and because of the elevated temperature the trapping by the shallow traps becomes predominant. The decay of current starts taking place and after some time an appreciable fall is observed. From an analysis of this character the trapping time, trap depth and... [ABSTRACT FROM AUTHOR]

A one-dimensional, transit-time analysis is carried out for a space-charge-limited solid-state device in the presence of traps. It is shown that the device yields a negative resistance under certain conditions. The trajectory equations, etc., are derived. The variation of the d.c. resistance with transit time, trap density, collision frequency, etc., is computed. The variation of the negative resistance with (transit angle--signal frequency multiplied by the transit time) for different values of the trap density and collision frequency is computed. It is found in general that the device has a negative resistance only for certain ranges of values of and that the value of the negative resistance reduces for larger values of . The value of the negative resistance increases with trap density, sample thickness and collision frequency. The value of the negative resistance is also increased with d.c. current density. Physical interpretations are given to explain the various results and a numerical example is given to compute the value of the negative resistance for a practical case. [ABSTRACT FROM AUTHOR]

In summary it appears that Christie et al.'s F Scale is not composed of two psychometrically opposite subscales, but rather of two independent subscales as is evidenced by the .08 correlation found by Klein (9) .` If one is interested in response sets, the measurement of which is dependent upon true reversals of the F + Scale, it is unlikely that they can be adequately measured with Christie a al.'s F Scale in undergraduate college samples. For ideologically sophisticated subjects the scales may be opposites, but they are not in the three regionally distinctive samples of undergraduates studied. For such samples one can expect no relationship between F + and F -. This was the finding reported by Christie et al. (6)-.10 correlation between the scales for undergraduates-but not given the critical scrutiny and replication it deserved. [ABSTRACT FROM AUTHOR]